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Sample records for epoxy coatings behavior

  1. Relationship between ion transport and the failure behavior of epoxy resin coatings

    International Nuclear Information System (INIS)

    Dong, Yuhua; Zhou, Qiong

    2014-01-01

    Highlights: •An epoxy resin-Q345 system with a sandwich structure was prepared. •Cl − ions permeated into epoxy resin coating prior to K + ions. •Free volume size and PAL increased when the coating was immersed into the solution. -- Abstract: An epoxy resin coating with a sandwich structure was prepared to investigate ion transport behavior in the coating. The macro- and micro- appearance of the coating immersed in 5 wt.% KCl solutions was observed by stereomicroscopy, scanning electron microscopy equipped with an energy dispersive spectrometer. The electrochemical property of the coating was characterized by electrochemical impedance spectroscopy, and change of free volume after immersion was characterized by positron annihilation lifetime spectroscopy. The results indicated that Cl − ions permeated into the coating prior to K + ions, the free volume size and positron annihilation lifetime of the coating increased during immersion

  2. Corrosion behavior of duplex polyaniline/epoxy coating on mild steel in 3% NaCl

    Directory of Open Access Journals (Sweden)

    Gvozdenović Milica M.

    2005-01-01

    Full Text Available The corrosion behavior and thermal stability of epoxy coatings electrodeposited on mild steel and on mild steel with electrochemically deposited polyaniline (PANI film were investigated by electrochemical impedance spectroscopy (EIS and thermo gravimetric analysis (TGA. The aim of the paper was to present new findings on the corrosion protection of mild steel by a duplex PANI/-epoxy coating in 3% NaCI solution and to determine the effect of thin PANI film on the protective properties of the coating. PANI film was deposited electrochemically on mild steel from an aqueous solution of 0.5 mol dm"3 sodium benzoate and 0.1 mol dm"3 aniline at a constant current density of 1.5 mA cm"2. Non-pigmented epoxy coatings on mild steel and on mild steel with PANI film were obtained by cathodic electrode position at constant voltage and stirring conditions. The resin concentration in the electrode position bath was 10 wt.% solid dispersion in water at pH 5.7. The applied voltage was 250 V, the temperature 26°C and the deposition time 3 min. It was shown that thin PANI film could be used to modify the surface of mild steel prior to epoxy coating deposition, due to the increased corrosion protection of a duplex PANI/epoxy coating comparing to an epoxy coating on mild steel in 3% NaCl solution.

  3. Degradation of modified carbon black/epoxy nanocomposite coatings under ultraviolet exposure

    International Nuclear Information System (INIS)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-01-01

    Graphical abstract: - Highlights: • Degradation behavior of modified Carbon Black (CB) epoxy coating was studied under UV irradiation using based on EIS technique. • By using SDS as a surfactant, nano particles of CB were uniformly dispersed in an epoxy matrix. • ATR-FTIR analysis showed that the CB coatings were degraded less than epoxy coating. • EIS results showed the coating with 2.5 wt% CB nanoparticles had higher corrosion resistance than neat epoxy. - Abstract: Degradation of epoxy coatings with and without Carbon Black (CB) nanoparticles under ultraviolet (UV) radiation were investigated using electrochemical impedance spectroscopy (EIS). Sodium dodecyl sulfate (SDS) was used to obtain a good dispersion of CB nanoparticles in a polymer matrix. TEM analysis proved a uniform dispersion of modified CB nanoparticles in epoxy coating. The coatings were subjected to UV radiation to study the degradation behavior and then immersed in 3.5 wt% NaCl. The results showed that the electrochemical behavior of neat epoxy coating was related to the formation and development of microcracks on the surface. The occurrence of microcracks on the surface of the coatings and consequently the penetration of ionic species reduced by adding CB nanoparticles into the formulation of the coatings. CB nanoparticles decreased degradation of CB coatings by absorbing UV irradiation. The ATR-FTIR results showed that decrease in the intensity of methyl group as main peak in presence of 2.5 wt% CB was lower than neat epoxy. In addition, the reduction in impedance of neat epoxy coating under corrosive environment was larger than CB coatings. The CB coating with 2.5 wt% nanoparticles had the highest impedance to corrosive media after 2000 h UV irradiation and 24 h immersion in 3.5 wt% NaCl.

  4. Degradation of modified carbon black/epoxy nanocomposite coatings under ultraviolet exposure

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi-Kahrizsangi, Ahmad, E-mail: ahmad_usk@yahoo.com [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Shariatpanahi, Homeira, E-mail: shariatpanahih@ripi.ir [Coating Research Center, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Neshati, Jaber [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Akbarinezhad, Esmaeil [Coating Research Center, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of)

    2015-10-30

    Graphical abstract: - Highlights: • Degradation behavior of modified Carbon Black (CB) epoxy coating was studied under UV irradiation using based on EIS technique. • By using SDS as a surfactant, nano particles of CB were uniformly dispersed in an epoxy matrix. • ATR-FTIR analysis showed that the CB coatings were degraded less than epoxy coating. • EIS results showed the coating with 2.5 wt% CB nanoparticles had higher corrosion resistance than neat epoxy. - Abstract: Degradation of epoxy coatings with and without Carbon Black (CB) nanoparticles under ultraviolet (UV) radiation were investigated using electrochemical impedance spectroscopy (EIS). Sodium dodecyl sulfate (SDS) was used to obtain a good dispersion of CB nanoparticles in a polymer matrix. TEM analysis proved a uniform dispersion of modified CB nanoparticles in epoxy coating. The coatings were subjected to UV radiation to study the degradation behavior and then immersed in 3.5 wt% NaCl. The results showed that the electrochemical behavior of neat epoxy coating was related to the formation and development of microcracks on the surface. The occurrence of microcracks on the surface of the coatings and consequently the penetration of ionic species reduced by adding CB nanoparticles into the formulation of the coatings. CB nanoparticles decreased degradation of CB coatings by absorbing UV irradiation. The ATR-FTIR results showed that decrease in the intensity of methyl group as main peak in presence of 2.5 wt% CB was lower than neat epoxy. In addition, the reduction in impedance of neat epoxy coating under corrosive environment was larger than CB coatings. The CB coating with 2.5 wt% nanoparticles had the highest impedance to corrosive media after 2000 h UV irradiation and 24 h immersion in 3.5 wt% NaCl.

  5. Friction and wear behavior of nanosilica-filled epoxy resin composite coatings

    International Nuclear Information System (INIS)

    Kang Yingke; Chen Xinhua; Song Shiyong; Yu Laigui; Zhang Pingyu

    2012-01-01

    Hydrophilic silica nanoparticles (abridged as nano-SiO 2 ) surface-capped with epoxide were dispersed in the solution of epoxy resin (abridged as EP) in tetrahydrofuran under magnetic stirring. Resultant suspension of nano-SiO 2 in EP was then coated onto the surface of glass slides and dried at 80 °C in a vacuum oven for 2 h, generating epoxy resin-nanosilica composite coatings (coded as EP/nano-SiO 2 ). EP coating without nano-SiO 2 was also prepared as a reference in the same manner. A water contact angle meter and a surface profiler were separately performed to measure the water contact angles and surface roughness of as-prepared EP/nano-SiO 2 composite coatings. The friction and wear behavior of as-prepared EP/nano-SiO 2 composite coatings sliding against steel in a ball-on-plate contact configuration under unlubricated condition was evaluated. Particularly, the effect of coating composition on the friction and wear behavior of the composite coatings was highlighted in relation to their microstructure and worn surface morphology examined by means of scanning electron microscopy. Results indicate that EP/nano-SiO 2 composite coatings have a higher surface roughness and water contact angle than EP coating. The EP-SiO 2 coatings doped with a proper amount of hydrophilic SiO 2 nanoparticles show lower friction coefficient than EP coating. However, the introduction of surface-capped nanosilica as the filler results in inconsistent change in the friction coefficient and wear rate of the filled EP-matrix composites; and it needs further study to achieve well balanced friction-reducing and antiwear abilities of the composite coatings for tribological applications.

  6. Mechanical behavior of nanocellulose coated jute/green epoxy composites

    Science.gov (United States)

    Jabbar, A.; Militký, J.; Ali, A.; Usman Javed, M.

    2017-10-01

    The present study was aimed to investigate the effect of nanocellulose coating on the mechanical behavior of jute/green epoxy composites. Cellulose was purified from waste jute fibers, converted to nanocellulose by acid hydrolysis and subsequently 3, 5 and 10 wt % of nanocellulose suspensions were coated over woven jute reinforcement. The composites were prepared by hand layup and compression molding technique. The surface topologies of treated jute fibers, jute cellulose nanofibrils (CNF), nanocellulose coated jute fabrics and fractured surfaces of composites were characterized by scanning electron microscopy (SEM). The prepared composites were evaluated for tensile, flexural, fatigue and fracture toughness properties. The results revealed the improvement in tensile modulus, flexural strength, flexural modulus, fatigue life and fracture toughness of composites with the increase in concentration of nanocellulose coating over jute reinforcement except the decrease in tensile strength.

  7. Degradation of modified carbon black/epoxy nanocomposite coatings under ultraviolet exposure

    Science.gov (United States)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-10-01

    Degradation of epoxy coatings with and without Carbon Black (CB) nanoparticles under ultraviolet (UV) radiation were investigated using electrochemical impedance spectroscopy (EIS). Sodium dodecyl sulfate (SDS) was used to obtain a good dispersion of CB nanoparticles in a polymer matrix. TEM analysis proved a uniform dispersion of modified CB nanoparticles in epoxy coating. The coatings were subjected to UV radiation to study the degradation behavior and then immersed in 3.5 wt% NaCl. The results showed that the electrochemical behavior of neat epoxy coating was related to the formation and development of microcracks on the surface. The occurrence of microcracks on the surface of the coatings and consequently the penetration of ionic species reduced by adding CB nanoparticles into the formulation of the coatings. CB nanoparticles decreased degradation of CB coatings by absorbing UV irradiation. The ATR-FTIR results showed that decrease in the intensity of methyl group as main peak in presence of 2.5 wt% CB was lower than neat epoxy. In addition, the reduction in impedance of neat epoxy coating under corrosive environment was larger than CB coatings. The CB coating with 2.5 wt% nanoparticles had the highest impedance to corrosive media after 2000 h UV irradiation and 24 h immersion in 3.5 wt% NaCl.

  8. Behavior of Epoxy-Coated Textured Reinforcing Bars

    Science.gov (United States)

    2018-04-01

    Cracking in bridge decks is a common but difficult problem to control. Both research and experience show that the use of epoxy-coated reinforcement, which is mandated by most state departments of transportation (DOTs) for bridge decks, increases c...

  9. The application of epoxy resin coating in grounding grid

    Science.gov (United States)

    Hu, Q.; Chen, Z. R.; Xi, L. J.; Wang, X. Y.; Wang, H. F.

    2018-01-01

    Epoxy resin anticorrosion coating is widely used in grounding grid corrosion protection because of its wide range of materials, good antiseptic effect and convenient processing. Based on the latest research progress, four kinds of epoxy anticorrosive coatings are introduced, which are structural modified epoxy coating, inorganic modified epoxy coating, organic modified epoxy coating and polyaniline / epoxy resin composite coating. In this paper, the current research progress of epoxy base coating is analyzed, and prospected the possible development direction of the anti-corrosion coating in the grounding grid, which provides a reference for coating corrosion prevention of grounding materials.

  10. Corrosion Protection of Steel by Epoxy-Organoclay Nanocomposite Coatings

    OpenAIRE

    Domna Merachtsaki; Panagiotis Xidas; Panagiotis Giannakoudakis; Konstantinos Triantafyllidis; Panagiotis Spathis

    2017-01-01

    The purpose of the present work was to study the corrosion behavior of steel coated with epoxy-(organo) clay nanocomposite films. The investigation was carried out using salt spray exposures, optical and scanning electron microscopy examination, open circuit potential, and electrochemical impedance measurements. The mechanical, thermomechanical, and barrier properties of pristine glassy epoxy polymer and epoxy-clay nanocomposites were examined. The degree of intercalation/exfoliation of clay ...

  11. Effect of pretreatments on electrodeposited epoxy coatings for electronic industries

    Directory of Open Access Journals (Sweden)

    Sironmani Palraj

    2016-02-01

    Full Text Available Waterborne epoxy coatings were prepared on aluminium (Al surfaces by cathodic electro-deposition on the pretreated surface of pickling, phosphating, chromating and anodizing. The electro-deposition experiments were done at two different voltages, 15 V and 25 V at room temperature in 10% epoxy coating formulations. Corrosion and thermal behavior of these coatings were investigated using electrochemical impedance spectroscopy (EIS and thermo gravimetric analysis (TGA. The coating exhibits better corrosion resistance in anodized Al surface than the other. But, TGA studies show that the thermal stability is higher in anodized and chromated Al surfaces. The surface morphology of these coatings were analyzed by SEM and AFM studies.

  12. Enhanced protective properties of epoxy/polyaniline-camphorsulfonate nanocomposite coating on an ultrafine-grained metallic surface

    International Nuclear Information System (INIS)

    Pour-Ali, Sadegh; Kiani-Rashid, Alireza; Babakhani, Abolfazl; Davoodi, Ali

    2016-01-01

    Highlights: • Preparing mild steel surface with ultrafine grains by wire brushing process. • Performance of a smart coating on micro- and nano-crystalline surfaces. • Corrosion evaluation, surface analysis and ac/dc electrochemical measurements. • Ultrafine surface grains improve protective behavior of epoxy/PANI-CSA coating. - Abstract: An ultrafine-grained surface layer on mild steel substrate with average grain size of 77 nm was produced through wire brushing process. Surface grain size was determined through transmission electron microscopy and X-ray diffraction methods. This substrate was coated with epoxy and an in situ synthesized epoxy/polyaniline-camphorsulfonate (epoxy/PANI-CSA) nanocomposite. The corrosion behavior was studied by open circuit potential, potentiodynamic polarization and impedance measurements. Results of electrochemical tests evidenced the enhanced protective properties of epoxy/PANI-CSA coating on the substrate with ultrafine-grained surface.

  13. Enhanced protective properties of epoxy/polyaniline-camphorsulfonate nanocomposite coating on an ultrafine-grained metallic surface

    Energy Technology Data Exchange (ETDEWEB)

    Pour-Ali, Sadegh, E-mail: pourali2020@ut.ac.ir; Kiani-Rashid, Alireza; Babakhani, Abolfazl; Davoodi, Ali

    2016-07-15

    Highlights: • Preparing mild steel surface with ultrafine grains by wire brushing process. • Performance of a smart coating on micro- and nano-crystalline surfaces. • Corrosion evaluation, surface analysis and ac/dc electrochemical measurements. • Ultrafine surface grains improve protective behavior of epoxy/PANI-CSA coating. - Abstract: An ultrafine-grained surface layer on mild steel substrate with average grain size of 77 nm was produced through wire brushing process. Surface grain size was determined through transmission electron microscopy and X-ray diffraction methods. This substrate was coated with epoxy and an in situ synthesized epoxy/polyaniline-camphorsulfonate (epoxy/PANI-CSA) nanocomposite. The corrosion behavior was studied by open circuit potential, potentiodynamic polarization and impedance measurements. Results of electrochemical tests evidenced the enhanced protective properties of epoxy/PANI-CSA coating on the substrate with ultrafine-grained surface.

  14. Adhesion between coating layers based on epoxy and silicone

    DEFF Research Database (Denmark)

    Svendsen, Jacob R.; Kontogeorgis, Georgios; Kiil, Søren

    2007-01-01

    The adhesion between a silicon tie-coat and epoxy primers, used in marine coating systems, has been studied in this work. Six epoxy coatings (with varying chain lengths of the epoxy resins), some of which have shown problems with adhesion to the tie-coat during service life, have been considered....... The experimental investigation includes measurements of the surface tension of the tie-coat and the critical surface tensions of the epoxies, topographic investigation of the surfaces of cured epoxy coatings via atomic force microscopy (AFM), and pull-off tests for investigating the strength of adhesion...... to the silicon/epoxy systems. Calculations for determining the roughness factor of the six epoxy coatings (based on the AFM topographies) and the theoretical work of adhesion have been carried out. The coating surfaces are also characterized based on the van Oss-Good theory. Previous studies on the modulus...

  15. Influence of Coating with Some Natural Based Materials on the Erosion Wear Behavior of Glass Fiber Reinforced Epoxy Resin

    OpenAIRE

    Aseel Basim Abdul Hussein; Emad Saadi AL-Hassani; Reem Alaa Mohamed

    2015-01-01

    In the present study, composites were prepared by Hand lay-up molding. The composites constituents were epoxy resin as a matrix, 6% volume fractions of glass fibers (G.F) as reinforcement and 3%, 6% volume fractions of preparation natural material (Rice Husk Ash, Carrot Powder, and Sawdust) as filler. Studied the erosion wear behavior and coating by natural wastes (Rice Husk Ash) with epoxy resin after erosion. The results showed the non – reinforced epoxy have lower resistance erosion than n...

  16. Characterization, optical properties and laser ablation behavior of epoxy resin coatings reinforced with high reflectivity ceramic particles

    Science.gov (United States)

    Li, Wenzhi; Kong, Jing; Wu, Taotao; Gao, Lihong; Ma, Zhuang; Liu, Yanbo; Wang, Fuchi; Wei, Chenghua; Wang, Lijun

    2018-04-01

    Thermal damage induced by high power energy, especially high power laser, significantly affects the lifetime and performance of equipment. High-reflectance coating/film has attracted considerable attention due to its good performance in the damage protection. Preparing a high-reflectance coating with high reaction endothermal enthalpy will effectively consume a large amount of incident energy and in turn protect the substrate from thermal damage. In this study, a low temperature process was used to prepare coatings onto substrate with complex shape and avoid thermal effect during molding. An advanced high reflection ceramic powder, La1‑xSrxTiO3+δ , was added in the epoxy adhesive matrix to improve the reflectivity of coating. The optical properties and laser ablation behaviors of coatings with different ceramic additive ratio of La1‑xSrxTiO3+δ and modified epoxy-La1‑xSrxTiO3+δ with ammonium polyphosphate coatings were investigated, respectively. We found that the reflectivity of coatings is extremely high due to mixed high-reflection La1‑xSrxTiO3+δ particles, up to 96% at 1070 nm, which can significantly improve the laser resistance. In addition, the ammonium polyphosphate modifies the residual carbon structure of epoxy resin from discontinuous fine particles structure to continuous and porous structure, which greatly enhances the thermal-insulation property of coating. Furthermore, the laser ablation threshold is improved obviously, which is from 800 W cm‑2 to 1000 W cm‑2.

  17. Corrosion protection of the reinforcing steels in chloride-laden concrete environment through epoxy/polyaniline–camphorsulfonate nanocomposite coating

    International Nuclear Information System (INIS)

    Pour-Ali, Sadegh; Dehghanian, Changiz; Kosari, Ali

    2015-01-01

    Highlights: • Epoxy/polyaniline–camphorsulfonate nanocomposite coating well protects steel rebar. • Coating performance is evaluated by impedance measurements up to 1 year. • Ultimate bond strength between the coated rebars and concrete is measured. • Self-compacting concrete shows better anticorrosive property compared to normal one. - Abstract: In this study, an epoxy/polyaniline–camphorsulfonate nanocomposite (epoxy/PANI–CSA) is employed to protect reinforcing steels in chloride-laden concrete environment. The synthesized nanocomposite was characterized using Fourier transform infrared spectroscopy and transmission electron microscopy. Bare, epoxy-coated and epoxy/PANI–CSA nanocomposite-coated steel rebars were embedded in normal and self-compacting concretes. To evaluate their corrosion behaviors, open circuit potential and impedance measurements were performed for the duration of 1 year. Ultimate bond strength of concrete with the reinforcement bars were measured in corroded and uncorroded conditions. It was found that epoxy/PANI–CSA coating provides good corrosion resistance and durable bond strength with concrete for steel rebars

  18. Enhanced protective properties of epoxy/polyaniline-camphorsulfonate nanocomposite coating on an ultrafine-grained metallic surface

    Science.gov (United States)

    Pour-Ali, Sadegh; Kiani-Rashid, Alireza; Babakhani, Abolfazl; Davoodi, Ali

    2016-07-01

    An ultrafine-grained surface layer on mild steel substrate with average grain size of 77 nm was produced through wire brushing process. Surface grain size was determined through transmission electron microscopy and X-ray diffraction methods. This substrate was coated with epoxy and an in situ synthesized epoxy/polyaniline-camphorsulfonate (epoxy/PANI-CSA) nanocomposite. The corrosion behavior was studied by open circuit potential, potentiodynamic polarization and impedance measurements. Results of electrochemical tests evidenced the enhanced protective properties of epoxy/PANI-CSA coating on the substrate with ultrafine-grained surface.

  19. Long-Term Atmospheric Corrosion Behavior of Epoxy Prime Coated Aluminum Alloy 7075-T6 in Coastal Environment

    Directory of Open Access Journals (Sweden)

    Sheng Zhang

    2018-06-01

    Full Text Available The atmospheric corrosion of epoxy prime coated aluminum alloy 7075-T6 exposed for 7, 12 and 20 years was investigated. The remaining thicknesses of epoxy prime coatings for macroscopically intact coating areas followed a normal distribution and decreased linearly. EIS results demonstrated that the corrosion resistance of the coating decreased with exposure time. After 20 years of exposure, the epoxy coating had lost its protection as cracks existed within the coating and exfoliation corrosion had occurred on the substrate. The substrate was sensitive to exfoliation corrosion through metallographic and TEM analysis. The corrosion products were mainly hydroxides of aluminum. The morphology and chemical compositions of the coating bubbling area and propagation characterizations of exfoliation corrosion were analyzed by SEM, EPMA and EDS. Cracks between the lumps of corrosion products provided the channels for the transmission of corrosion mediums. Furthermore, the mechanical model was proposed to analyze the propagation characterization of exfoliation corrosion.

  20. Epoxy-based broadband antireflection coating for millimeter-wave optics.

    Science.gov (United States)

    Rosen, Darin; Suzuki, Aritoki; Keating, Brian; Krantz, William; Lee, Adrian T; Quealy, Erin; Richards, Paul L; Siritanasak, Praween; Walker, William

    2013-11-20

    We have developed epoxy-based, broadband antireflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixing three types of epoxy and doping with strontium titanate powder required for the high dielectric mixtures. At 140 K, the band-integrated absorption loss in the coatings was suppressed to less than 1% for the two-layer coating, and below 10% for the three-layer coating.

  1. Stochastic estimation of acoustic impedance of glass-reinforced epoxy coating 128-134

    Energy Technology Data Exchange (ETDEWEB)

    Kim, No Hyu [School of MechatronicEngineering, Korea University of Technology and Education, Chunan (Korea, Republic of); Nah, Hwan Seon [Structural Engineering Lab., Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2014-04-15

    An epoxy coating applied to the concrete surface of a containment building deteriorates in hazardous environments such as those containing radiation, heat, and moisture. Unlike metals, the epoxy coating on a concrete liner absorbs and discharges moisture during the degradations process, so it has a different density and volume during service. In this study, acoustic impedance was adopted for characterizing the degradation of a glass-reinforced epoxy coating using the acoustic reflection coefficient (reflectance) on a rough epoxy coating. For estimating the acoustic reflectance on a wavy epoxy coating surface, a probabilistic model was developed to represent the multiple irregular reflections of the acoustic wave from the wavy surface on the basis of the simulated annealing technique. A number of epoxy-coated concrete specimens were prepared and exposed to accelerated aging conditions to induce an artificial aging degradation in them. The acoustic impedance of the degraded epoxy coating was estimated successfully by minimizing the error between a waveform calculated from the mathematical model and a waveform measured from the surface of the rough coating.

  2. Stochastic estimation of acoustic impedance of glass-reinforced epoxy coating 128-134

    International Nuclear Information System (INIS)

    Kim, No Hyu; Nah, Hwan Seon

    2014-01-01

    An epoxy coating applied to the concrete surface of a containment building deteriorates in hazardous environments such as those containing radiation, heat, and moisture. Unlike metals, the epoxy coating on a concrete liner absorbs and discharges moisture during the degradations process, so it has a different density and volume during service. In this study, acoustic impedance was adopted for characterizing the degradation of a glass-reinforced epoxy coating using the acoustic reflection coefficient (reflectance) on a rough epoxy coating. For estimating the acoustic reflectance on a wavy epoxy coating surface, a probabilistic model was developed to represent the multiple irregular reflections of the acoustic wave from the wavy surface on the basis of the simulated annealing technique. A number of epoxy-coated concrete specimens were prepared and exposed to accelerated aging conditions to induce an artificial aging degradation in them. The acoustic impedance of the degraded epoxy coating was estimated successfully by minimizing the error between a waveform calculated from the mathematical model and a waveform measured from the surface of the rough coating.

  3. Enhanced protective properties and UV stability of epoxy/graphene nanocomposite coating on stainless steel

    Directory of Open Access Journals (Sweden)

    H. Alhumade

    2016-12-01

    Full Text Available Epoxy-Graphene (E/G nanocomposites with different loading of graphene were prepared via in situ prepolymerization and evaluated as protective coating for Stainless Steel 304 (SS304. The prepolymer composites were spin coated on SS304 substrates and thermally cured. Transmission Electron Microscopy (TEM and Scanning Electron Microscopy (SEM were utilized to examine the dispersion of graphene in the epoxy matrix. Epoxy and E/G nanocomposites were characterized using X-ray diffraction (XRD and Fourier Transform Infrared (FTIR techniques and the thermal behavior of the prepared coatings is analyzed using Thermogravimetric analysis (TGA and Differential scanning calorimetry (DSC. The corrosion protection properties of the prepared coatings were evaluated using Electrochemical Impedance Spectroscopy (EIS and Cyclic Voltammetry (CV measurements. In addition to corrosion mitigation properties, the long-term adhesion performance of the coatings was evaluated by measuring the adhesion of the coatings to the SS304 substrate after 60 days of exposure to 3.5 wt% NaCl medium. The effects of graphene loading on the impact resistance, flexibility, and UV stability of the coating are analyzed and discussed. SEM was utilized to evaluate post adhesion and UV stability results. The results indicate that very low graphene loading up to 0.5 wt % significantly enhances the corrosion protection, UV stability, and impact resistance of epoxy coatings.

  4. Corrosion performance of epoxy-coated reinforcement in aggressive environments

    Science.gov (United States)

    Vaca Cortes, Enrique

    The objective of this research was to investigate the integrity and corrosion performance of epoxy-coated reinforcement in aggressive environments. A series of experimental studies were conducted: (a) hot water immersion and knife adhesion testing for assessment of coating adhesion; (b) materials and procedures for repairing coating damage; (c) degree of mechanical damage caused during concrete placement when using metal head and rubber head vibrators; (d) accelerated corrosion of coated bars embedded in macrocell and beam specimens placed in a corrosive environment for more than four years. The effects of coating condition and amount of damage, repaired vs. unrepaired damage, bar fabrication, and concrete cracking were studied. Regardless of coating condition, the performance of epoxy-coated bars was better than that of uncoated bars. Unlike black bars, coated bars did not exhibit deep pitting or substantial loss of cross section at crack locations. Damage to epoxy coating was the most significant factor affecting corrosion performance. Bars with coating in good condition, without any visible damage, performed best. The greater the size and frequency of damage, the more severe and extensive the amount of corrosion. The performance of bars that were fabricated or bent after coating was worse than that of coated straight bars. Mixing coated and uncoated bars in the same concrete member led to undesirable performance. Patching damaged coating reduced but did not prevent corrosion, particularly at bar ends. The most important factor in coating repair was the type and properties of the patching material. Surface preparation prior to coating had little effect. The absence of cracks in the concrete delayed, but did not prevent the onset of corrosion of coated bars. During consolidation of concrete, rubber head vibrators caused less damage to epoxy-coated reinforcement than did comparable metal heads. Hot water and adhesion tests were useful and practical for evaluating

  5. ETV Program Report: Coatings for Wastewater Collection Systems - Standard Cement Materials, Epoxy Coating 4553

    Science.gov (United States)

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Ma...

  6. Preparation and Properties of Epoxy Resin-Coated Micro-Sized Ferrosilicon Powder

    OpenAIRE

    Ku,Jiangang; Chen,Huihuang; He,Kui; Yan,Quanxiang

    2016-01-01

    Ferrosilicon powder surface coated with a dense epoxy resin membrane was prepared via coating precipitation methods using silane coupling agents as the modifier and epoxy resin as the coating agent. FTIR, FESEM, MPMS-XL, and TG-DSC were used to analyze the morphology, surface composition, magnetic property and thermostability of ferrosilicon powder before and after the modification and coating. The experimental results indicate that epoxy resin membranes of a certain thickness were successful...

  7. Adhesion of epoxy primer to hydrotalcite conversion coated AA2024

    Science.gov (United States)

    Leggat, Robert Benton, III

    Hydrotalcite-based (HT) conversion coatings are being developed as an environmentally benign alternative to chromate conversion coatings (CCC). Accelerated exposure tests were conducted on epoxy primed, HT-modified AA2024 to gauge service performance. HT-based conversion coatings did not perform as well as the CCC when used with an epoxy primer. The current HT chemistries are optimized for stand-alone corrosion protection, however additional research into the primer/HT interactions is necessary before they can be implemented within a coating scheme. The relative contribution of mechanical and physico-chemical interactions in controlling adhesion has been investigated in this study. Practical adhesion tests were used to assess the dry and wet bond strength of epoxy primer on HT coatings using the pull-off tensile strength (POTS) as the figure of merit. The practical adhesion of HT coated samples generally fell between that observed for the CCC and bare AA2024. Laboratory testing was done to assess the physical and chemical properties of HT coatings. Contact angle measurements were performed using powders representative of different HT chemistries to evaluate the dispersive and acid-base character of the surface. The wet POTS correlated with the electrodynamic (dipole + dispersive) parameter of the surface tension. The HT surfaces were found to be predominantly basic. Given the basicity of epoxy, these results indicate that increasing the acidic character of HT coatings may increase the adhesion performance. This was supported by electrokinetic measurements in which the dry POTS was found to increase with decreasing conversion coating iso-electric point. The correlations with the dry and wet state adhesion are interpreted as indicating that dry state adhesion is optimized by minimizing unfavorable polar interactions between the basic epoxy and HT interfaces. Wet state adhesion, where polar interactions are disrupted, is dictated by non-polar bonding. FTIR

  8. Synthesis of cuprous oxide epoxy nanocomposite as an environmentally antimicrobial coating.

    Science.gov (United States)

    M El Saeed, Ashraf; Abd El-Fattah, M; Azzam, Ahmed M; Dardir, M M; Bader, Magd M

    2016-08-01

    Cuprous oxide is commonly used as a pigment; paint manufacturers begin to employ cuprous oxide as booster biocides in their formulations, to replace the banned organotins as the principal antifouling compounds. Epoxy coating was reinforced with cuprous oxide nanoparticles (Cu2O NPs). The antibacterial as well as antifungal activity of Cu2O epoxy nanocomposite (Cu2O EN) coating films was investigated. Cu2O NPs were also experimented for antibiofilm and time-kill assay. The thermal stability and the mechanical properties of Cu2O EN coating films were also investigated. The antimicrobial activity results showed slowdown, the growth of organisms on the Cu2O EN coating surface. TGA results showed that incorporating Cu2O NPs into epoxy coating considerably enhanced the thermal stability and increased the char residue. The addition of Cu2O NPs at lower concentration into epoxy coating also led to an improvement in the mechanical resistance such as scratch and abrasion. Cu2O NPs purity was confirmed by XRD. The TEM photograph demonstrated that the synthesized Cu2O NPs were of cubic shape and the average diameter of the crystals was around 25nm. The resulting perfect dispersion of Cu2O NPs in epoxy coating revealed by SEM ensured white particles embedded in the epoxy matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Epoxy coatings for anticorrosion challenges: a link between chemistry and performance?

    Energy Technology Data Exchange (ETDEWEB)

    Sauvant-Moynot, Valerie; Schweitzer, Sylvie; Grenier, Jacky; Duval, Sebastien [Institut Francais du Petrole, 1 et 4 avenue Bois Preau, 92450 Rueil-Malmaison (France)

    2004-07-01

    Epoxy coatings have been used extensively for pipeline protection in the oil and gas industries over the past decades. Thank to their outstanding adhesive properties, epoxy resins are classically used for external coating of offshore pipelines although cathodic protection is applied. They provide corrosion protection while being used as neat coating or as primer layer in a three-layer coating. Protection of internal pipelines devoted to gas transport is another application of epoxy coatings. Whatever the case, the choice of the right epoxy formulation should be adapted to the service conditions, namely exposition medium and temperature, in order to provide efficient and sustainable corrosion protection. Epoxy resins constitute a wide family and classical formulations may not fulfill the requirements of today's challenges: as pipelines are require d to operate in more and more difficult conditions, coatings are expected to function in higher temperature conditions; additionally, practical conditions such as temporary injection of methanol make the environmental exposure of the epoxy coating harsher. Therefore, there is a need of a better knowledge of technical performance and limitations of high temperature epoxy resins. This paper examined the influence of the epoxy network architecture on their protection properties and durability while exposed to distilled / sea water at 110 deg. C and to methanol at room temperature. The objective was to investigate the link between resin chemistry and final performance with respect to anticorrosion applications. Five epoxy resin formulations mixed in stoichiometric proportions were cured and post-cured to infinite extent in order to achieve densely cross-linked networks exhibiting controlled and reproducible architectures. Gravimetric and pressurised differential scanning calorimetry (DSC) measurements were performed to evaluate the plasticization effect of both water and methanol on formulations under study. The related

  10. Failure behavior of nano-SiO2 fillers epoxy coating under hydrostatic pressure

    International Nuclear Information System (INIS)

    Liu Li; Cui Yu; Li Ying; Zhang Tao; Wang Fuhui

    2012-01-01

    The failure of organic coating (epoxy resin filled with 5 mass% nano-SiO 2 particles) on mild steel under high hydrostatic pressure (35 atm) has been studied compared with that under atmospheric pressure (1 atm), using impedance measurements, gravimetric testing, adhesion testing and scanning electron microscopy (SEM). The results show that high hydrostatic pressure accelerated the failure of the organic coating by promoting diffusion of water in the coating, which speeds up water spread and electrochemical reactions at the interface. The roughness of the coating and steel has been discussed from point of view of their respective fractal dimensions D fc and D fdl , as deduced from impedance measurements

  11. Preparation and Electrochemical Properties of Graphene/Epoxy Resin Composite Coating

    Science.gov (United States)

    Liao, Zijun; Zhang, Tianchi; Qiao, Sen; Zhang, Luyihang

    2017-11-01

    The multilayer graphene powder as filler, epoxy modified silicone resin as film-forming agent, anticorrosion composite coating has been created using sand dispersion method, the electrochemical performance was compared with different content of graphene composite coating and pure epoxy resin coating. The open circuit potential (OCP), potentiodynamic polarization curves (Tafel Plot) and electrochemical impedance spectroscopy (EIS) were tested. The test results showed that the anti-corrosion performance of multilayer graphene added has improved greatly, and the content of the 5% best corrosion performance of graphene composite coating.

  12. Thermal conductive epoxy enhanced by nanodiamond-coated carbon nanotubes

    Science.gov (United States)

    Zhao, Bo; Jiang, Guohua

    2017-11-01

    Nanodiamond (ND) particles were coated on the surface of carbon nanotubes (CNTs) by chemical reactions. Reliable bonding was formed by the combination of acyl chloride on NDs and amine group on CNTs. ND coated CNTs (CNT-ND) were dispersed into epoxy to fabricate thermal conductive resins. The results show that the surface energy of CNTs is decreased by the coated NDs, which is contributed to the excellent dispersion of CNT-NDs in the epoxy matrix. The heat-transfer channels were built by the venous CNTs cooperating with the coated NDs, which not only plays an effective role of heat conduction for CNTs and NDs, but also avoids the electrical leakage by the protection of NDs surrounding outside of CNTs. Electrical and thermal conductance measurements demonstrate that the influence of the CNT-ND incorporation on the electrical conductance is minor, however, the thermal conductivity is improved significantly for the epoxy filled with CNT-ND.[Figure not available: see fulltext.

  13. Electrochemical and anticorrosion behaviors of hybrid functionalized graphite nano-platelets/tripolyphosphate in epoxy-coated carbon steel

    International Nuclear Information System (INIS)

    Mohammadi, Somayeh; Shariatpanahi, Homeira; Taromi, Faramarz Afshar; Neshati, Jaber

    2016-01-01

    Highlights: • FGNP was combined with TPP to obtain a hybrid nano-particle. • TEM image showed uniform distribution of the hybrid nanoparticles in epoxy coating. • FGNP is a substrate for linking of TPP anions by hydrogen bonding. • FGNP as an accelerator, provides rapid iron phosphate passive film formation. • The hybrid nano-particle can provide long-term corrosion protection. - Abstract: Functionalized graphite nano-platelets (FGNP) were combined with tripolyphosphate (TPP) to gain a hybrid nano-particle (FGNP-TPP) with homogenous dispersion in epoxy, resulting in an excellent anti-corrosion coating for carbon steel substrate. Characterization analyses of the hybrid nano-particle were performed by FT-IR, SEM, XRD and TEM. TPP was linked to FGNP nano-particles by hydrogen bondings. Different epoxy coatings formulated with 1 wt.% of FGNP, FGNP-TPP and TPP were evaluated. Electrochemical investigations, salt spray and pull-off tests showed that the hybrid nano-particle can provide long-term corrosion protection compared to FGNP and TPP due to synergistic effect between FGNP as an accelerator and TPP as a corrosion inhibitor to produce a uniform and stable iron-phosphate passive film with high surface coverage.

  14. Electrochemical and anticorrosion behaviors of hybrid functionalized graphite nano-platelets/tripolyphosphate in epoxy-coated carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Somayeh, E-mail: somaye.mohammadi32@aut.ac.ir [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shariatpanahi, Homeira [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Taromi, Faramarz Afshar [Department of Polymer Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Neshati, Jaber [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of)

    2016-08-15

    Highlights: • FGNP was combined with TPP to obtain a hybrid nano-particle. • TEM image showed uniform distribution of the hybrid nanoparticles in epoxy coating. • FGNP is a substrate for linking of TPP anions by hydrogen bonding. • FGNP as an accelerator, provides rapid iron phosphate passive film formation. • The hybrid nano-particle can provide long-term corrosion protection. - Abstract: Functionalized graphite nano-platelets (FGNP) were combined with tripolyphosphate (TPP) to gain a hybrid nano-particle (FGNP-TPP) with homogenous dispersion in epoxy, resulting in an excellent anti-corrosion coating for carbon steel substrate. Characterization analyses of the hybrid nano-particle were performed by FT-IR, SEM, XRD and TEM. TPP was linked to FGNP nano-particles by hydrogen bondings. Different epoxy coatings formulated with 1 wt.% of FGNP, FGNP-TPP and TPP were evaluated. Electrochemical investigations, salt spray and pull-off tests showed that the hybrid nano-particle can provide long-term corrosion protection compared to FGNP and TPP due to synergistic effect between FGNP as an accelerator and TPP as a corrosion inhibitor to produce a uniform and stable iron-phosphate passive film with high surface coverage.

  15. Protection of Steel Rebar in Salt-Contaminated Cement Mortar Using Epoxy Nanocomposite Coatings

    Directory of Open Access Journals (Sweden)

    The Huu Nguyen

    2018-01-01

    Full Text Available Epoxy reinforced with two kinds of nanoparticles dealing with nano-SiO2 and nano-Fe2O3 was coated on steel rebar embedded in a chloride contaminated cement mortar. NaCl was added to the fresh Portland cement paste (at 0.3% and 0.5% by weight of cement to simulate the chloride contamination at the critical level. The effect of incorporating nanoparticles on the corrosion resistance of epoxy-coated steel rebar was investigated by linear potentiodynamic polarization and electrochemical impedance spectroscopy. For the 0.3 wt.% chloride mortars, the electrochemical monitoring of the coated steel rebars during immersion for 56 days in 0.1 M NaOH solutions suggested the beneficial role of nano-Fe2O3 particles in significantly improving the corrosion resistance of the epoxy-coated rebar. After 56 days of immersion, the nano-Fe2O3 reduced the corrosion current of epoxy-coated rebar by a factor of 7.9. When the chloride concentration in the cement mortar was 0.5 wt.%, the incorporation of nanoparticles into the epoxy matrix did not enhance the corrosion resistance of epoxy coating for the rebar. At this critical level, chloride ions initiated rebar corrosion through nanoparticles at the epoxy/rebar interface.

  16. Determination of Young's modulus of epoxy coated polyethylene micro-cantilever using phase-shift shadow moiré method

    Science.gov (United States)

    Lim, J. H.; Ratnam, M. M.; Azid, I. A.; Mutharasu, D.

    2011-11-01

    Young's moduli of various epoxy coated polyethylene terephthalate (PET) micro-cantilevers were determined from the deflection results obtained using the phase-shift shadow moiré (PSSM) method. The filler materials for epoxy coatings were aluminum and graphite powders that were mixed with epoxy at various percentages. Young's moduli were calculated from theory based on the deflection results. The PET micro-cantilever coated with aluminum-epoxy coating showed increasing value of Young's modulus when the ratios of the aluminum-epoxy were increased. The graphite-epoxy coating on the PET micro-cantilever also showed the same trend. The experimental results also show that Young's modulus of the graphite-epoxy coating is higher than aluminum-epoxy coating in comparison at the same mixing ratio.

  17. Preparations and applications in UV curing coatings of epoxy acrylates containing carboxyl

    International Nuclear Information System (INIS)

    Wu Yu Min

    1999-01-01

    This paper introduces preparations of epoxy acrylates containing carboxyl through the reactions of epoxy acrylates with butanedioic anhydride, pentanedioic anhydride, cis-butenedioic anhydride, phthalic anhydride, tetrabromophthalic anhydride and -tetrahydrophthalic anhydride. These epoxy acrylates containing carboxyl have been applied to UV-curing coatings and their effects on properties of UV-curing coatings have been studied

  18. Epoxy-based broadband anti-reflection coating for millimeter-wave optics

    OpenAIRE

    Rosen, Darin; Suzuki, Aritoki; Keating, Brian; Krantz, William; Lee, Adrian T.; Quealy, Erin; Richards, Paul L.; Siritanasak, Praween; Walker, William

    2013-01-01

    We have developed epoxy-based, broadband anti-reflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixin...

  19. Corrosion study of the graphene oxide and reduced graphene oxide-based epoxy coatings

    Science.gov (United States)

    Ghauri, Faizan Ali; Raza, Mohsin Ali; Saad Baig, Muhammad; Ibrahim, Shoaib

    2017-12-01

    This work aims to determine the effect of graphene oxide (GO) and reduced graphene oxide (rGO) incorporation as filler on the corrosion protection ability of epoxy coatings in saline media. GO was derived from graphite powder following modified Hummers’ method, whereas rGO was obtained after reduction of GO with hydrazine solution. About 1 wt.% of GO or rGO were incorporated in epoxy resin by solution mixing process followed by ball milling. GO and rGO-based epoxy composite coatings were coated on mild steel substrates using film coater. The coated samples were characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests after 1 and 24 h immersion in 3.5% NaCl. The results suggested that GO-based epoxy composite coatings showed high impedance and low corrosion rate.

  20. Velocity Measurement of ultrasonic for evaluation of aging epoxy coating in containment structure of nuclear power plant

    International Nuclear Information System (INIS)

    Eun, Gil Soo; Kim, Noh Yu; Nah, Hwan Seon; Song, Young Chol

    2001-01-01

    Relative variation of ultrasonic velocity in aging epoxy coating in nuclear plant is measured for evaluation of the degradation of the epoxy coating. Time delay for ultrasound to travel through the epoxy film due to change of ultrasonic velocity is measured indirectly using ultrasonic interferometry which compares two reflection waves from the same point of coating surface at two different distances. Magnitude of the difference of two waves increases or decreases depending on change of the time of flight of ultrasound in the epoxy film caused by heat damage in the epoxy coating. Based on the transfer functions of the wedge and the epoxy coating in frequency domain, the reflection wave is analyzed and related to the velocity of ultrasound in the epoxy coating. A specially designed conical wedge is adopted to minimize the waviness effect of the surface of the epoxy coating. Epoxy films are fabricated, degraded under the accelerated aging conditions and tested to evaluate the change of ultrasonic velocity in the films. The experimental results show that the method can be applied to evaluate quantitatively the sealing quality of the epoxy coating.

  1. Solid Particle Erosion Behaviors of Carbon-Fiber Epoxy Composite and Pure Titanium

    Science.gov (United States)

    Cai, Feng; Gao, Feng; Pant, Shashank; Huang, Xiao; Yang, Qi

    2016-01-01

    Rotor blades of Bell CH-146 Griffon helicopter experience excessive solid particle erosion at low altitudes in desert environment. The rotor blade is made of an advanced light-weight composite which, however, has a low resistance to solid particle erosion. Coatings have been developed and applied to protect the composite blade. However, due to the influence of coating process on composite material, the compatibility between coating and composite base, and the challenges of repairing damaged coatings as well as the inconsistency between the old and new coatings, replaceable thin metal shielding is an alternative approach; and titanium, due to its high-specific strength and better formability, is an ideal candidate. This work investigates solid particle erosion behaviors of carbon-fiber epoxy composite and titanium in order to assess the feasibility of titanium as a viable candidate for erosion shielding. Experiment results showed that carbon-fiber epoxy composite showed a brittle erosion behavior, whereas titanium showed a ductile erosion mode. The erosion rate on composite was 1.5 times of that on titanium at impingement angle 15° and increased to 5 times at impact angle 90°.

  2. Corrosion protection performance of waterborne epoxy coatings containing self-doped polyaniline nanofiber

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Shihui [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211 (China); Chen, Cheng; Cui, Mingjun [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Li, Wei [Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211 (China); Zhao, Haichao, E-mail: zhaohaichao@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China)

    2017-06-15

    Highlights: • Self-dopedpolyaniline (SPANi) with good conductivity and dispersibility in water was copolymerized by aniline and its derivative. • Environmental friendly SPANi/epoxy composite coating with remarkable anti-corrosion performance was prepared. • The corrosion product of pure epoxy or composite coating was characterized by X-ray diffraction pattern and scanning electron microscope (SEM). - Abstract: Self-doped sulfonated polyaniline (SPANi) nanofiber was synthesized by the copolymerization of 2-aminobenzenesulfonic acid (ASA) and aniline via a rapid mixing polymerization approach. The chemical structure of SPANi was investigated by the Fourier-transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV–vis spectra and X-ray diffraction (XRD) pattern. The as-prepared SPANi nanofibers had 45 nm average diameter and length up to 750 nm as measured by scanning electron microscope (SEM) and transmission electron microscope (TEM). The self-doped SPANi nanofiber possessed excellent aqueous solubility, good conductivity (0.11 S/cm) and reversible redox activity, making it suitable as a corrosion inhibitor for waterborne coatings. The prepared SPANi/waterborne epoxy composite coatings exhibited remarkably improved corrosion protection compared with pure waterborne epoxy coating as proved by the polarization curves and electrochemical impedance spectroscopy (EIS). The passivation effect of SPANi nanofiber and the corrosion products beneath the epoxy coatings immersed in 3.5% NaCl solution as a function of time were also investigated in this study.

  3. Corrosion protection performance of waterborne epoxy coatings containing self-doped polyaniline nanofiber

    International Nuclear Information System (INIS)

    Qiu, Shihui; Chen, Cheng; Cui, Mingjun; Li, Wei; Zhao, Haichao; Wang, Liping

    2017-01-01

    Highlights: • Self-dopedpolyaniline (SPANi) with good conductivity and dispersibility in water was copolymerized by aniline and its derivative. • Environmental friendly SPANi/epoxy composite coating with remarkable anti-corrosion performance was prepared. • The corrosion product of pure epoxy or composite coating was characterized by X-ray diffraction pattern and scanning electron microscope (SEM). - Abstract: Self-doped sulfonated polyaniline (SPANi) nanofiber was synthesized by the copolymerization of 2-aminobenzenesulfonic acid (ASA) and aniline via a rapid mixing polymerization approach. The chemical structure of SPANi was investigated by the Fourier-transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV–vis spectra and X-ray diffraction (XRD) pattern. The as-prepared SPANi nanofibers had 45 nm average diameter and length up to 750 nm as measured by scanning electron microscope (SEM) and transmission electron microscope (TEM). The self-doped SPANi nanofiber possessed excellent aqueous solubility, good conductivity (0.11 S/cm) and reversible redox activity, making it suitable as a corrosion inhibitor for waterborne coatings. The prepared SPANi/waterborne epoxy composite coatings exhibited remarkably improved corrosion protection compared with pure waterborne epoxy coating as proved by the polarization curves and electrochemical impedance spectroscopy (EIS). The passivation effect of SPANi nanofiber and the corrosion products beneath the epoxy coatings immersed in 3.5% NaCl solution as a function of time were also investigated in this study.

  4. Fault-tolerant epoxy-silane coating for corrosion protection of magnesium alloy AZ31

    NARCIS (Netherlands)

    Lamaka, S.V.; Xue, H.B.; Meis, N.N.A.H.; Esteves, A.C.C.; Ferreira, M.G.S.

    2015-01-01

    In this work, a hybrid epoxy-silane coating was developed for corrosion protection of magnesium alloy AZ31. The average thickness of the film produced by dip-coating procedure was 14 µm. The adhesion strength of the epoxy-silane coating to the Mg substrate was evaluated by pull-off tests and was

  5. Electron beam processed plasticized epoxy coatings for surface protection

    International Nuclear Information System (INIS)

    Ibrahim, Mervat S.; Mohamed, Heba A.; Kandile, Nadia G.; Said, Hossam M.; Mohamed, Issa M.

    2011-01-01

    Highlights: · Coating formulations with EA 70%, HD 20%, and castor oil 10% under 1 Mrad pass -1 irradiation dose showed the best adhesion and passed bending tests. · The prepared EP-SF-An adduct improve anti-corrosion properties of coatings without any significant effect on physical, mechanical and chemical properties of the cured film. The optimum amount of aniline adduct as corrosion inhibitor was found to be 0.4 g for 100 g of coating formulation. · The corrosion inhibition efficiency of the prepared adduct competed the commercial efficiency. - Abstract: Epoxy acrylate oligomer (EA) was plasticized by adding different plasticizers such as epoxidized soybean oil, glycerol and castor oil and cured by electron beam (EB). Different irradiation doses (1, 2.5 and 5 Mrad pass -1 ) were used in the curing process. The effect of both different irradiation doses and plasticizers on the end use performance properties of epoxy acrylate coating namely, pencil hardness, bending test, adhesion test, acid and alkali resistance test were studied. It was observed that incorporation of castor oil in epoxy acrylate diluted by 1,6-hexanediol diacrylate (HD) monomer with a ratio (EA 70%, HD 20%, castor oil 10%) under 1 Mrad pass -1 irradiation dose improved the physical, chemical and mechanical properties of cured films than the other plasticizer. Sunflower free fatty acid was epoxidized in situ under well established conditions. The epoxidized sunflower free fatty acids (ESFA) were subjected to react with aniline in sealed ampoules under inert atmosphere at 140 deg. C. The produced adducts were added at different concentrations to epoxy acrylate coatings under certain EB irradiation dose and then evaluated as corrosion inhibitors for carbon steel surfaces in terms of weight loss measurements and corrosion resistance tests. It was found that, addition of 0.4 g of aniline adduct to 100 g epoxy acrylate formula may give the best corrosion protection for carbon steel and compete the

  6. Monitoring underlying epoxy-coated St-37 corrosion via 8-hydroxyquinoline as a fluorescent indicator

    Science.gov (United States)

    Roshan, Shamim; Sarabi Dariani, Ali Asghar; Mokhtari, Javad

    2018-05-01

    In the present study, successful performance of 8-hydroxyquinoline (8-HQ) as a ferric ion sensitive indicator is described. 8-HQ was used in epoxy coating because of its desirable properties. It doesn't exhibit premature fluorescence when mixed with coating precursors. Additionally it shows fluorescence turn-on mechanism upon chelate formation with Fe2+/Fe3+ ions produced during anodic reaction. The effect of different concentrations of 8-HQ (0.05, 0.1, 0.5 and 1 wt.%) incorporated in the epoxy coating on corrosion detection as well as optical and electrochemical behavior of the applied coating were studied. The fluorescence property of 8-HQ/Fe3+ solutions was evaluated by using fluorometer. The UV-Visible spectroscopy was used to investigate the effect of 8-HQ presence in the coating on transparency of the free films of the samples. The corrosion detection was performed by fluorescence microscope and the anti-corrosion performance of coated samples containing different concentrations of 8-HQ was studied using salt spray standard test and electrochemical impedance spectroscopy (EIS). The results of UV-Visible spectroscopy demonstrated that increasing 8-HQ concentration causes a slight decrease in coating transparency. According to the results of electrochemical impedance spectroscopy (EIS) measurements, the polarization resistance of the coated St-37 sample containing 0.1 wt.% 8-HQ was about 109 Ohm cm2 after 6 weeks immersion in corrosive electrolyte, while St-37 plates coated with other 8-HQ concentrations showed decreased resistance levels of about 106 Ohm cm2, during the same immersion period. Based on fluorescence microscopic investigation, as a result of incorporating 8-HQ into the epoxy matrix, fluorescence could be observed in regions where Fe2+/Fe3+ ions were produced through anodic reactions. This method is capable of detecting corrosion in situ at early stages before the metal surface suffers serious damages.

  7. Tribological properties of epoxy composite coatings reinforced with functionalized C-BN and H-BN nanofillers

    Science.gov (United States)

    Yu, Jingjing; Zhao, Wenjie; Wu, Yinghao; Wang, Deliang; Feng, Ruotao

    2018-03-01

    A series of epoxy resin (EP) composite coatings reinforced with functionalized cubic boron nitride (FC-BN) and functionalized hexagonal boron nitride (FH-BN) were fabricated successfully on 316L stainless steel by hand lay-up technique. The structure properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The morphologies were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, UMT-3 tribometer and surface profiler were used to investigate tribological behaviors of as-prepared composite coatings under dry friction and seawater conditions respectively. The results demonstrated that the presence of FC-BN or FH-BN fillers could greatly decrease the friction coefficient (COF) and wear rate of epoxy, in addition, composite coatings possess better tribological properties under seawater condition which was attributed to the lubricating effect of seawater. Moreover, FC-BN endows the composite coatings the highest wear resistance, and FH-BN /EP composite coatings exhibited the best friction reduction performance which is attributed to the self-lubricating performance of lamella structure for FH-BN sheet.

  8. Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

    Science.gov (United States)

    Pham, Gia Vu; Truc Trinh, Anh; To, Thi Xuan Hang; Duong Nguyen, Thuy; Trang Nguyen, Thu; Hoan Nguyen, Xuan

    2014-09-01

    In this study Fe3O4/CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe3O4) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe3O4/CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe3O4/CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe3O4/CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe3O4/CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe3O4/CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe3O4/CNTs composite in the epoxy matrix.

  9. Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

    International Nuclear Information System (INIS)

    Pham, Gia Vu; Trinh, Anh Truc; Hang To, Thi Xuan; Nguyen, Thuy Duong; Nguyen, Thu Trang; Nguyen, Xuan Hoan

    2014-01-01

    In this study Fe 3 O 4 /CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe 3 O 4 ) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe 3 O 4 /CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe 3 O 4 /CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe 3 O 4 /CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe 3 O 4 /CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe 3 O 4 /CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe 3 O 4 /CNTs composite in the epoxy matrix. (paper)

  10. Assessment of integrity of containment coating (Epoxy) using beta radiometry and NDT techniques

    International Nuclear Information System (INIS)

    Pujala, Usha; Sujatha, P.N.; Kumar, Amit; Menaka, M.; Subramanian, V.; Sriniyas, C.V.; Baskaran, R.; Venkataraman, B.; Preetha, R.; Kumar, J. Ashok

    2018-01-01

    The inner sides of walls of reactor containments and other fuel handling areas are coated with paint made of epoxy resins mainly for ease of decontamination and protecting rebar from corrosion environment. In addition, this gives the advantage in terms of ensuring additional leak tightness of reactor containment building (RCB) during the hypothetical Core Disruptive Accident (CDA) of Sodium Cooled Fast Reactors (SFR). During CDA, RCB will be bottled-up with sodium aerosols along with fuel and fission product aerosols. Sodium aerosols undergo chemical changes with progress of time to form hydroxide, carbonate and bicarbonate species upon reaction with atmospheric constituents. Of which, hydroxide aerosols are highly corrosive due to alkaline nature and it can cause damages to the epoxy coating. In this context, experiments have been conducted at ATF to assess the integrity of epoxy coating under the alkaline atmospheric conditions. Plywood, ordinary concrete and zinc plates are coated with epoxy paint and integrity of the coating is checked by exposing to sodium aerosols using beta radiometry technique (BRT), NDT techniques and gravimetric analysis. The results are presented in this paper

  11. Effect of epoxy resin sealing on corrosion resistance of arc spraying aluminium coating using cathode electrophoresis method

    Science.gov (United States)

    Pang, Xuming; Wang, Runqiu; Wei, Qian; Zhou, Jianxin

    2018-01-01

    Arc-sprayed Al coating was sealed with epoxy resin using the cathode electrophoresis method. The anti-corrosion performance of the coatings sealed with epoxy resin was studied by means of a 3.5 wt.% NaCl solution test at 40 °C. For comparison, the anti-corrosion performance of Al coating sealed with boiling water was also performed under the same conditions. The results show that epoxy resin with a thickness of about 20 microns can entirely cover open pores and decreases the surface roughness of the as-sprayed Al coating, and the epoxy resin even permeates into the gaps among lamellar splats from open pores. After corrosion, the thickness of the epoxy resin layer is unchanged and can still cover the as-sprayed Al coating entirely. However, the thickness of Al coating sealed with boiling water decreases from 100 to 40 microns, which indicates that the arc-sprayed Al coating has much better corrosion resistance than the Al coating sealed with boiling water. Meanwhile, the content of substituted benzene ring in the epoxy resin increases, but aromatic ring decreases according to the fourier transform infrared spectra, which will cause the rigidity of the epoxy resin to increase, but the toughness slightly decreases after corrosion.

  12. Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Mingjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Ren, Siming [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Chen, Jia; Liu, Shuan [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhang, Guangan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao, Haichao, E-mail: zhaohaichao@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xue, Qunji, E-mail: qjxue@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2017-03-01

    Highlights: • Hexagonal boron nitride nanosheets were well dispersed by using water-soluble carboxylated aniline trimer as dispersant. • The best corrosion performance of waterborne epoxy coatings was achieved with the addition of 1 wt% h-BN. • The decrease of the pores and defects of coating matrix inhibits the diffusion and water absorption of corrosive medium in the coating. - Abstract: Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT{sup −}) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT{sup −}, as proved by Raman and UV–vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 10{sup 6} Ω cm{sup 2}) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

  13. Novel epoxy-benzoxazine water-based emulsions with reactive benzoxazine surfactants for coatings

    Directory of Open Access Journals (Sweden)

    M. Krajnc

    2014-08-01

    Full Text Available Novel epoxy-benzoxazine emulsions designed for water-based coatings were prepared and investigated. Bisphenol A-based epoxy resins with molar weights of 340, 377 and 1750 g/mol along with epoxidized soybean oil were emulsified using mono- and bi-functional benzoxazine surfactants, which are able to react with epoxy resins at their cure temperature. The structure of synthesized surfactants carrying one or two polyether chains was confirmed using Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance and differential scanning calorimetry. Stability of emulsions was verified by particle diameters measurements. Coatings, made directly from emulsions, were dried and cured at elevated temperature using 3,3'-dimetoxybenzidine as curing agent to ensure a highly cross-linked structure of thermosetting films. Curing process, thermal properties and hardness of cured films were investigated. It was found that benzoxazine molecules were well incorporated into the epoxy network upon curing, which ensures no void structure of cured copolymer and enhanced coating properties.

  14. Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

    Science.gov (United States)

    Cui, Mingjun; Ren, Siming; Chen, Jia; Liu, Shuan; Zhang, Guangan; Zhao, Haichao; Wang, Liping; Xue, Qunji

    2017-03-01

    Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT-) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT-, as proved by Raman and UV-vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 106 Ω cm2) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

  15. Effects of surface roughness, texture and polymer degradation on cathodic delamination of epoxy coated steel samples

    International Nuclear Information System (INIS)

    Khun, N.W.; Frankel, G.S.

    2013-01-01

    Highlights: ► Cathodic delamination of epoxy coated steel samples was studied using SKP. ► Delamination of the coating decreased with increased substrate surface roughness. ► Delamination of the coating was faster on the substrate with parallel surface scratches. ► Delamination of the coating exposed to weathering conditions increased with prolonged exposure. - Abstract: The Scanning Kelvin Probe (SKP) technique was used to investigate the effects of surface roughness, texture and polymer degradation on cathodic delamination of epoxy coated steel. The cathodic delamination rate of the epoxy coatings dramatically decreased with increased surface roughness of the underlying steel substrate. The surface texture of the steel substrates also had a significant effect in that samples with parallel abrasion lines exhibiting faster cathodic delamination in the direction of the lines compared to the direction perpendicular to the lines. The cathodic delamination kinetics of epoxy coatings previously exposed to weathering conditions increased with prolonged exposure due to pronounced polymer degradation. SEM observation confirmed that the cyclic exposure to UV radiation and water condensation caused severe deterioration in the polymer structures with surface cracking and erosion. The SKP results clearly showed that the cathodic delamination of the epoxy coatings was significantly influenced by the surface features of the underlying steel substrates and the degradation of the coatings.

  16. Effect of Montmorillonite Nanogel Composite Fillers on the Protection Performance of Epoxy Coatings on Steel Pipelines.

    Science.gov (United States)

    Atta, Ayman M; El-Saeed, Ashraf M; Al-Lohedan, Hamad A; Wahby, Mohamed

    2017-06-02

    Montmorillonite (MMT) clay mineral is widely used as filler for several organic coatings. Its activity is increased by exfoliation via chemical modification to produce nanomaterials. In the present work, the modification of MMT to form nanogel composites is proposed to increase the dispersion of MMT into epoxy matrices used to fill cracks and holes produced by the curing exotherms of epoxy resins. The dispersion of MMT in epoxy improved both the mechanical and anti-corrosion performance of epoxy coatings in aggressive marine environments. In this respect, the MMT surfaces were chemically modified with different types of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) nanogels using a surfactant-free dispersion polymerization technique. The effect of the chemical structure, nanogel content and the interaction with MMT surfaces on the surface morphology, surface charges and dispersion in the epoxy matrix were investigated for use as nano-filler for epoxy coatings. The modified MMT nanogel epoxy composites showed excellent resistance to mechanical damage and salt spray resistance up to 1000 h. The interaction of MMT nanogel composites with the epoxy matrix and good response of AMPS nanogel to sea water improve their ability to act as self-healing materials for epoxy coatings for steel.

  17. Cage and linear structured polysiloxane/epoxy hybrids for coatings: Surface property and film permeability.

    Science.gov (United States)

    Ma, Yanli; He, Ling; Jia, Mengjun; Zhao, Lingru; Zuo, Yanyan; Hu, Pingan

    2017-08-15

    Three polysiloxane/epoxy hybrids obtained by evolving cage- or linear-structured polysiloxane into poly glycidyl methacrylate (PGMA) matrix are compared used as coatings. One is the cage-structured hybrid of P(GMA/MA-POSS) copolymer obtained by GMA and methacrylisobutyl polyhedral oligomeric silsesquioxane (MA-POSS) via free radical polymerization, the other two are PGMA/NH 2 -POSS and PGMA/NH 2 -PDMS hybrids by cage-structured aminopropyllsobutyl POSS (NH 2 -POSS) or linear-structured diamino terminated poly(dimethylsiloxane) (NH 2 -PDMS) to cure PGMA. The effect of MA-POSS, NH 2 -POSS and NH 2 -PDMS on polysiloxane/epoxy hybrid films is characterized according to their surface morphology, transparency, permeability, adhesive strength and thermo-mechanical properties. Due to caged POSS tending to agglomerate onto the film surface, P(GMA/MA-POSS) and PGMA/NH 2 -POSS films exhibit much more heterogeneous surfaces than PGMA/NH 2 -PDMS film, but the well-compatibility between epoxy matrix and MA-POSS has provided P(GMA/MA-POSS) film with much higher transmittance (98%) than PGMA/NH 2 -POSS film (24%), PGMA/NH 2 -PDMS film (27%) and traditional epoxy resin film (5%). The introduction of polysiloxane into epoxy matrix is confirmed to create hybrids with strong adhesive strength (526-1113N) and high thermos-stability (T g =262-282°C), especially the cage-structured P(GMA/MA-POSS) hybrid (1113N and 282°C), but the flexible PDMS improves PGMA/NH 2 -PDMS hybrid with much higher storage modulus (519MPa) than PGMA/NH 2 -POSS (271MPa), which suggests that PDMS is advantage in improving the film stiffness than POSS cages. However, cage-structured P(GMA/MA-POSS) and PGMA/NH 2 -POSS indicate higher permeability than PGMA/NH 2 -PDMS and traditional epoxy resin. Comparatively, the cage-structured P(GMA/MA-POSS) hybrid is the best coating in transparency, permeability, adhesive strength and thermostability, but linear-structured PGMA/NH 2 -PDMS hybrid behaviors the best coating in

  18. An experimental study on moisture absorption for jute-epoxy composite with coatings exposed to different pH media

    Directory of Open Access Journals (Sweden)

    Radhika Londhe

    2016-09-01

    The purpose of this work is to study the moisture absorption and mechanical properties of jute-epoxy composites. Jute fibres are treated with NaOH before manufacturing of composite laminate in order to improve adhesion with epoxy material. Further jute-epoxy composite specimens were coated with epoxy resin and acrylic paint. Composite specimens with and without coatings are subjected to absorption in solutions of different pH media, for 28 days (666 h. The effect of coatings on reduction in moisture absorption for jute-epoxy composite is presented in this current work.

  19. Effects of surface treatment of aluminium alloy 1050 on the adhesion and anticorrosion properties of the epoxy coating

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi Golru, S., E-mail: samanesharifi@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413 Tehran (Iran, Islamic Republic of); Attar, M.M., E-mail: attar@aut.ac.ir [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 15875-4413 Tehran (Iran, Islamic Republic of); Ramezanzadeh, B. [Department of Surface Coating and Corrosion, Institute for Color Science and Technology, No. 59,Vafamanesh St, Hosainabad Sq, Lavizan, Tehran (Iran, Islamic Republic of)

    2015-08-01

    Highlights: • Aluminium alloy 1050 was treated by zirconium-based (Zr) conversion coating. • The surface morphology and surface free energy of the samples were obtained. • The adhesion properties of the epoxy coating was studied on the treated samples. • The corrosion resistance of the epoxy coating was enhanced on treated samples. - Abstract: The objective of this work is to investigate the effects of zirconium-based (Zr) conversion coating on the adhesion properties and corrosion resistance of an epoxy/polyamide coating applied on the aluminium alloy 1050 (AA1050). Field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectrum (EDS), atomic force microscope (AFM) and contact angle measuring device were employed in order to characterize the surface characteristics of the Zr treated AA1050 samples. The epoxy/polyamide coating was applied on the untreated and Zr treated samples. The epoxy coating adhesion to the aluminium substrate was evaluated by pull-off test before and after 30 days immersion in 3.5% w/w NaCl solution. In addition, the electrochemical impedance spectroscopy (EIS) and salt spray tests were employed to characterize the corrosion protection properties of the epoxy coating applied on the AA1050 samples. Results revealed that the surface treatment of AA1050 by zirconium conversion coating resulted in the increase of surface free energy and surface roughness. The dry and recovery (adhesion strength after 30 days immersion in the 3.5 wt% NaCl solution) adhesion strengths of the coatings applied on the Zr treated aluminium samples were greater than untreated sample. In addition, the adhesion loss of the coating applied on the Zr treated aluminium substrate was lower than other samples. Also, the results obtained from EIS and salt spray test clearly revealed that the Zr conversion coating could enhance the corrosion protective performance of the epoxy coating significantly.

  20. Effect of nitrogen-doped carbon dots on the anticorrosion properties of waterborne epoxy coatings

    Science.gov (United States)

    Ren, Siming; Cui, Mingjun; Zhao, Haichao; Wang, Liping

    2018-06-01

    In this work, nitrogen-doped carbon dots (NCDs) are prepared by solvothermal method and the effect of NCDs on the anticorrosion property of waterborne epoxy (EP) is investigated. Scanning probe microscopy results show that the size of the NCDs is about 4–6 nm. In addition, the anticorrosion property of NCD-incorporated waterborne epoxy coatings is investigated via electrochemical techniques and scanning electron microscopy. Electrochemical results demonstrate that the impedance modulus of 2.0% NCDs/EP is 364 times higher than that of blank EP after 800 h of immersion, indicating significant enhancement in the anticorrosion property of waterborne epoxy coating. The reason is that NCDs with lots of surface functional groups can connect with waterborne epoxy to suppress enlargement of the pores, and reduce the diffusion of oxygen in the coating, thus cutting off the connection between the substrate and oxygen, and delaying corrosion of the substrate.

  1. Comparative study on Ti/Zr/V and chromate conversion treated aluminum alloys: Anti-corrosion performance and epoxy coating adhesion properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wen; Li, Wenfang, E-mail: mewfli@163.com; Mu, Songlin; Fu, Nianqing; Liao, Zhongmiao

    2017-05-31

    Highlights: • The surface roughness and surface free energy of the AA6063 are significantly increased after TZVCC treatment. • The anti-corrosion performance of the AA6063 is effectively enhanced after TZVCC treatment. • Both the corrosion resistance and wet adhesion properties of the epoxy coating on the AA6063 are noticeably improved after TZVCC treatment. - Abstract: In this study, a Ti/Zr/V conversion coating (TZVCC) was deposited on the surface of aluminum alloy 6063 (AA6063) as an alternative of the chromate conversion coating (CCC). Both the TZVCC treated AA6063 (TZVCC/AA6063) and CCC treated AA6063 (CCC/AA6063) were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and contact angle measuring device. The anti-corrosion performance of the TZVCC/AA6063 and CCC/AA6063 was evaluated by electrochemical measurements and neutral salt spray tests. It showed that both the surface roughness and surface free energy of the AA6063 were significantly increased after TZVCC treatment. The anti-corrosion performance of TZVCC/AA6063 was superior to that of CCC/AA6063. In addition, the effects of the TZVCC and CCC on the adhesion properties and anti-corrosion performance of epoxy coating applied on samples were examined by pull-off tests and electrochemical impedance spectroscopy (EIS). The dry, wet and recovery adhesive strengths of the epoxy coating on TZVCC treated samples (epoxy coated TZVCC/AA6063) were very close to those of epoxy coating on CCC treated ones (epoxy coated CCC/AA6063). The epoxy coated TZVCC/AA6063 showed better corrosion resistance than the epoxy coated CCC/AA6063 and epoxy coated AA6063.

  2. Effect of titania particles on the microstructure and properties of the epoxy resin coatings on sintered NdFeB permanent magnets

    International Nuclear Information System (INIS)

    Xu, J.L.; Huang, Z.X.; Luo, J.M.; Zhong, Z.C.

    2014-01-01

    The nanometer titania particles enhanced epoxy resin composite coatings were prepared on the sintered NdFeB permanent magnets by cathodic electrophoretic deposition. The effects of titania particle concentrations on the microstructure and properties of the epoxy coatings were investigated by surface and cross-sectional morphologies observation, surface roughness and microhardness measurement, H 2 SO 4 solution immersion test, neutral salt spray test and magnetic properties measurement. The results showed that the thickness of epoxy coatings with and without the titania particles addition was about 40 μm. The titania particles could be uniformly dispersed and embedded in the epoxy matrix if the titania particles concentration was lower than 40 g/l. With increasing titania particle concentrations, the number of the particles embedded in the epoxy matrix increased and the surface roughness and microhardness of the composite coatings increased. At the same time, the weight loss of the coated samples immersed in H 2 SO 4 solution decreased and the neutral salt spray time of the coated samples prolonged. It could be concluded that the titania particles did not change the thickness of the epoxy coatings and did not deteriorate the magnetic properties of NdFeB substrates, but could greatly improve the microhardness and corrosion resistance of the epoxy coatings. - Highlights: • The titania particles enhanced epoxy resin coatings were prepared on sintered NdFeB by cathodic electrophoretic deposition. • The titania particles could be uniformly dispersed and embedded in the epoxy resin matrix. • With increasing titania concentrations, the surface roughness and the microhardness of composite coatings increased. • The addition of titania particles greatly improved the corrosion resistance of the epoxy coatings. • The composition coatings did not deteriorate the magnetic properties of NdFeB substrates

  3. Effect of titania particles on the microstructure and properties of the epoxy resin coatings on sintered NdFeB permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.L., E-mail: jlxu@nchu.edu.cn; Huang, Z.X.; Luo, J.M.; Zhong, Z.C., E-mail: zzhong.2006@yahoo.com.cn

    2014-04-15

    The nanometer titania particles enhanced epoxy resin composite coatings were prepared on the sintered NdFeB permanent magnets by cathodic electrophoretic deposition. The effects of titania particle concentrations on the microstructure and properties of the epoxy coatings were investigated by surface and cross-sectional morphologies observation, surface roughness and microhardness measurement, H{sub 2}SO{sub 4} solution immersion test, neutral salt spray test and magnetic properties measurement. The results showed that the thickness of epoxy coatings with and without the titania particles addition was about 40 μm. The titania particles could be uniformly dispersed and embedded in the epoxy matrix if the titania particles concentration was lower than 40 g/l. With increasing titania particle concentrations, the number of the particles embedded in the epoxy matrix increased and the surface roughness and microhardness of the composite coatings increased. At the same time, the weight loss of the coated samples immersed in H{sub 2}SO{sub 4} solution decreased and the neutral salt spray time of the coated samples prolonged. It could be concluded that the titania particles did not change the thickness of the epoxy coatings and did not deteriorate the magnetic properties of NdFeB substrates, but could greatly improve the microhardness and corrosion resistance of the epoxy coatings. - Highlights: • The titania particles enhanced epoxy resin coatings were prepared on sintered NdFeB by cathodic electrophoretic deposition. • The titania particles could be uniformly dispersed and embedded in the epoxy resin matrix. • With increasing titania concentrations, the surface roughness and the microhardness of composite coatings increased. • The addition of titania particles greatly improved the corrosion resistance of the epoxy coatings. • The composition coatings did not deteriorate the magnetic properties of NdFeB substrates.

  4. Corrosion Protection of Phenolic-Epoxy/Tetraglycidyl Metaxylediamine Composite Coatings in a Temperature-Controlled Borax Environment

    Science.gov (United States)

    Xu, Wenhua; Wang, Zhenyu; Han, En-Hou; Liu, Chunbo

    2017-12-01

    The failure behavior for two kinds of phenolic-epoxy/tetraglycidyl metaxylediamine composite coatings in 60 °C borax aqueous solution was evaluated using electrochemical methods (EIS) combined with scanning electron microscopy, confocal laser scanning microscope, water immersion test, and Raman spectrum. The main focus was on the effect of curing agent on the corrosion protection of coatings. Results revealed that the coating cured by phenolic modified aromatic amine possessed more compact cross-linked structure, better wet adhesion, lower water absorption (0.064 mg h-1 cm-2) and its impedance values was closed to 108 Ω cm2 after immersion for 576 h, while the coating cured by modified aromatic ring aliphatic amine was lower than 105 Ω cm2. The corrosion mechanism of the two coatings is discussed.

  5. Towards Washable Electrotextile UHF RFID Tags: Reliability Study of Epoxy-Coated Copper Fabric Antennas

    Directory of Open Access Journals (Sweden)

    Shiqi Wang

    2015-01-01

    Full Text Available We investigate the impact of washing on the performance of passive UHF RFID tags based on dipole antennas fabricated from copper fabric and coated with protective epoxy coating. Initially, the tags achieved read ranges of about 8 meters, under the European RFID emission regulation. To assess the impact of washing on the performance of the tags, they were washed repeatedly in a washing machine and measured after every washing cycle. Despite the reliability challenges related to mechanical stress, the used epoxy coating was found to be a promising coating for electrotextile tags in moist conditions.

  6. Steel Protective Coating Based on Plasticized Epoxy Acrylate Formulation Cured by Electron Beam Irradiation

    International Nuclear Information System (INIS)

    Ibrahim, M.S.; Said, H.M.; Mohamed, I.M.; Mohamed, H.A.; Kandile, N.G.

    2011-01-01

    Electron beam (EB) was used to cure coatings based on epoxy acrylate oligomer (EA) and different plasticizers such as epoxidized soybean oil, glycerol and castor oil. The effect of irradiation doses (10, 25, 50 kGy) on the curing epoxy acrylate formulations containing plasticizers was studied. In the addition, the effect of the different plasticizers on the end use performance properties of epoxy acrylate coatings such as hardness, bending, adhesion, acid and alkali resistance tests were investigated. It was observed that the incorporation of castor oil in epoxy acrylate, diluted by 1,6 hexandiol diacrylate monomer (HD) with a ratio (EA 70%, HD 20%, castor oil 10%) under the dose 10 kGy improved the physical, chemical and mechanical properties of cured films than the other plasticizers. On the other hand, sunflower free fatty acids were epoxidized in-situ under well established conditions and then was subjected to react with aniline in sealed ampoules under inert atmosphere at 140 degree C. The produced adduct was added at different concentrations to epoxy acrylate coatings under certain EB irradiation dose and then evaluated as corrosion inhibitors for carbon steel surfaces in terms of weight loss measurements and corrosion resistance tests. It was observed that the formula containing 0.4 gm of aniline adduct / 100 gm epoxy acrylate resin gave the best corrosion protection for carbon steel

  7. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    International Nuclear Information System (INIS)

    Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-01-01

    Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO 2 , ZrO 2 , V 2 O 5 , Al 2 O 3 , etc.), metal fluoride (ZrF 4 , AlF 3 , etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  8. Tensile strength of glass fibres with carbon nanotube–epoxy nanocomposite coating: Effects of CNT morphology and dispersion state

    OpenAIRE

    Siddiqui, Naveed A.; Li, Erin L.; Sham, Man-Lung; Tang, Ben Zhong; Gao, Shang Lin; Mäder, Edith; Kim, Jang-Kyo

    2010-01-01

    A study has been made of a concept of 'healing' coatings applied onto the brittle fibre surface to reduce the stress concentrations and thus to improve the reinforcing efficiency in a composite. Coatings made from neat epoxy and carbon nanotube (CNT) reinforced epoxy nanocomposite were applied onto the individual glass fibres as well as rovings. It is shown that the 0.3 wt.% CNT–epoxy nanocomposite coating gave rise to a significant increase in tensile strength of the single fibre for all gau...

  9. ELABORATION OF AN EPOXY COATING REINFORCED WITH ZIRCONIUM CARBIDE NANOSTRUCTURES

    Directory of Open Access Journals (Sweden)

    Lucia G. Díaz-Barriga

    2013-12-01

    Full Text Available This work shows the preparation of a transparent epoxy coating reinforced with 200 PPM of zirconium carbide nanostructures. The nanostructures of ZrC were prepared by mechanosynthesis. The additive characteristics analyzed by X-ray diffraction (XRD and scanning electron microscopy (SEM were presented. Epoxy coating adhesion on a steel plate was analyzed using MEB. Thermogravimetric analysis (TGA was performed to the reinforced paints between 20-700 °C. The reinforced enamel was compared with an enamel without nanostructures. There is not vaporization of reinforced enamel at a 95 y 100 °C with ZrC particles size of 10 µm y 120 nm respectively. The final enamel degradation is slower when there is a 14% by weight of the residue and 426 °C with 120nm diameter particles.

  10. Ultrasound-assisted synthesis of zinc molybdate nanocrystals and molybdate-doped epoxy/PDMS nanocomposite coatings for Mg alloy protection.

    Science.gov (United States)

    Eduok, Ubong; Szpunar, Jerzy

    2018-06-01

    Zinc molybdate (ZM) is a safer anticorrosive additive for cooling systems when compared with chromates and lead salts, due to its insolubility in aqueous media. For most molybdate pigments, their molybdate anion (MoO 4 -2 ) acts as an anionic inhibitor and its passivation capacity is comparable with chromate anion (CrO 4 -2 ). To alleviate the environmental concerns involving chromates-based industrial protective coatings, we have proposed new alternative in this work. We have synthesized ZM nanocrystals via ultrasound-assisted process and encapsulated them within an epoxy/PDMS coating towards corrosion protection. The surface morphology and mechanical properties of these ZM doped epoxy/PDMS nanocomposite coatings is exhaustively discussed to show the effect of ZM content on protective properties. The presence of ZM nanocrystals significantly contributed to the corrosion barrier performance of the coating while the amount of ZM nanocrystals needed to prepare an epoxy coating with optimum barrier performance was established. Beyond 2 wt% ZM concentration, the siloxane-structured epoxy coating network became saturated with ZM pigments. This further broadened inherent pores channels, leading to the percolation of corrosion chloride ions through the coating. SEM evidence has revealed proof of surface delamination on ZM3 coating. A model mechanism of corrosion resistance has been proposed for ZM doped epoxy/PDMS nanocomposite coatings from exhaustive surface morphological investigations and evidence. This coating matrix may have emerging applications in cooling systems as anticorrosive surface paints as well as create an avenue for environmental corrosion remediation. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wen; Li, Wenfang, E-mail: mewfli@scut.edu.cn; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-10-30

    Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO{sub 2}, ZrO{sub 2}, V{sub 2}O{sub 5}, Al{sub 2}O{sub 3}, etc.), metal fluoride (ZrF{sub 4}, AlF{sub 3}, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  12. Erosion protection of carbon-epoxy composites by plasma-sprayed coatings

    International Nuclear Information System (INIS)

    Alonso, F.; Fagoaga, I.; Oregui, P.

    1991-01-01

    This paper deals with the production of plasma-sprayed erosion-resistant coatings on carbon-fibre - epoxy composites, and the study of their erosion behaviour. The heat sensitivity of the composite substrate requires a specific spraying procedure in order to avoid its degradation. In addition, several bonding layers were studied to allow spraying of the protective coatings. Two different functional coatings were sprayed onto an aluminium-glass bonding layer, a WC-12Co cermet and an Al 2 O 3 ceramic oxide. The microstructure and properties of these coatings were studied and their erosion behaviour determined experimentally in an erosion-testing device. (orig.)

  13. Wear-resistant and electromagnetic absorbing behaviors of oleic acid post-modified ferrite-filled epoxy resin composite coating

    Science.gov (United States)

    Wang, Wenjie; Zang, Chongguang; Jiao, Qingjie

    2015-03-01

    The post-modified Mn-Zn ferrite was prepared by grafting oleic acid on the surface of Mn-Zn ferrite to inhibit magnetic nanoparticle aggregation. Fourier Transform Infrared (FT-IR) spectroscopy was used to characterize the particle surfaces. The friction and electromagnetic absorbing properties of a thin coating fabricated by dispersing ferrite into epoxy resin (EP) were investigated. The roughness of the coating and water contact angle were measured using the VEECO and water contact angle meter. Friction tests were conducted using a stainless-steel bearing ball and a Rockwell diamond tip, respectively. The complex permittivity and complex permeability of the composite coating were studied in the low frequency (10 MHz-1.5 GHz). Surface modified ferrites are found to improve magnetic particles dispersion in EP resulting in significant compatibility between inorganic and organic materials. Results also indicate that modified ferrite/EP coatings have a lower roughness average value and higher water contact angle than original ferrite/EP coatings. The enhanced tribological properties of the modified ferrite/EP coatings can be seen from the increased coefficient value. The composite coatings with modified ferrite are observed to exhibit better reflection loss compared with the coatings with original ferrite.

  14. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Science.gov (United States)

    Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-10-01

    An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO2, ZrO2, V2O5, Al2O3, etc.), metal fluoride (ZrF4, AlF3, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  15. The effects of addition of poly(vinyl) alcohol (PVA) as a green corrosion inhibitor to the phosphate conversion coating on the anticorrosion and adhesion properties of the epoxy coating on the steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir; Vakili, H.; Amini, R.

    2015-02-01

    Highlights: • Room temperature zinc phosphate coating was applied on the surface of steel sample. • Poly(vinyl) alcohol was added to the phosphating bath as a green corrosion inhibitor. • The adhesion and anticorrosion properties of the epoxy coating were investigated. • PVA decreased the phosphate crystal size and porosity. • PVA enhanced the corrosion protection and adhesion properties of the epoxy coating. - Abstract: Steel substrates were chemically treated by room temperature zinc phosphate conversion coating. Poly(vinyl) alcohol (PVA) was added to the phosphate solution as a green corrosion inhibitor. Finally, the epoxy/polyamide coating was applied on the untreated and surface treated steel samples. The effects of PVA on the morphological properties of the phosphate coating were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle measuring device. The adhesion properties of the epoxy coatings applied on the surface treated samples were investigated by pull-off and cathodic delamination tests. Also, the anticorrosion properties of the epoxy coatings were studied by electrochemical impedance spectroscopy (EIS). Results showed that addition of PVA to the phosphate coating increased the population density of the phosphate crystals and decreased the phosphate grain size. The contact angle of the steel surface treated by Zn-PVA was lower than Zn treated one. The corrosion resistance of the epoxy coating was considerably increased on the steel substrate treated by zinc phosphate conversion coating containing PVA. PVA also enhanced the adhesion properties of the epoxy coating to the steel surface and decreased the cathodic delamination significantly.

  16. Advanced Nanocomposite Coatings of Fusion Bonded Epoxy Reinforced with Amino-Functionalized Nanoparticles for Applications in Underwater Oil Pipelines

    OpenAIRE

    Patricia A. Saliba; Alexandra A. P. Mansur; Herman S. Mansur

    2016-01-01

    The performance of fusion-bonded epoxy coatings can be improved through advanced composite coatings reinforced with nanomaterials. Hence, in this study a novel organic-inorganic nanocomposite finish was designed, synthesized, and characterized, achieved by adding γ-aminopropyltriethoxysilane modified silica nanoparticles produced via sol-gel process in epoxy-based powder. After the curing process of the coating reinforced with nanoparticles, the formation of a homogenous novel nanocomposite w...

  17. Atmospheric corrosion resistance of epoxy duplex coated electrogalvanized steel exposed in marine, industrial and urban sites at pakistan

    International Nuclear Information System (INIS)

    Bano, H.; Kazmi, S.A.

    2017-01-01

    An epoxy based duplex coating system (Electrogalvanized Mild Steel/Etch Primer/Epoxy-Polyamide Primer/ Epoxy-Amine Topcoat System) embedded with iron oxide, zinc chromate and titanium dioxide pigments was studied to ascertain its corrosion resistant synergistic performance at various anthropogenic sites of Karachi coastal city while salt spray test was also executed for reference. Coating performance was ascertained by visual morphological inspection, gloss measurements, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) analysis and by Fourier Transform Infrared (FTIR) Spectroscopy. SEM and EDX results corroborated high degradation of epoxy coating at marine site experiment as substantial increment in oxygen/carbon ratio and high concentration of Ti at coating surface due to ex-corporation of pigments were noticed. Worst performance of epoxy coating at marine test site as compared to salt spray testing may be due to the salt-laden winds of Karachi coastal city and corrosive constituents incorporated in atmospheres from industrial and automobiles exhaust. General diminution trend in gloss value, depletion of morphological features witnessed through SEM micrographs, curtailment of aryl ether and aromatic nuclei signals in FTIR spectrum, and emergence of new peaks in the 1620-1800 cm-1 region correspond to formation of new oxidation products; concluded that an insignificant protection offered by the epoxy coating due to its outdoor aging which led to ex-capsulation of pigments under moist conditions. Appraisal of these results have furnished an average coating performance correlation of 547.5 hpy (hours of salt spray test equivalence per year exposure test) at marine test site and 528 hpy at industrial test site in terms of blistering while equivalence mean in terms of rusting were found 680 hpy and 567 hpy at marine and industrial test sites respectively. (author)

  18. Advanced Nanocomposite Coatings of Fusion Bonded Epoxy Reinforced with Amino-Functionalized Nanoparticles for Applications in Underwater Oil Pipelines

    Directory of Open Access Journals (Sweden)

    Patricia A. Saliba

    2016-01-01

    Full Text Available The performance of fusion-bonded epoxy coatings can be improved through advanced composite coatings reinforced with nanomaterials. Hence, in this study a novel organic-inorganic nanocomposite finish was designed, synthesized, and characterized, achieved by adding γ-aminopropyltriethoxysilane modified silica nanoparticles produced via sol-gel process in epoxy-based powder. After the curing process of the coating reinforced with nanoparticles, the formation of a homogenous novel nanocomposite with the development of interfacial reactions between organic-inorganic and inorganic-inorganic components was observed. These hybrid nanostructures produced better integration between nanoparticles and epoxy matrix and improved mechanical properties that are expected to enhance the overall performance of the system against underwater corrosion.

  19. SYNTHESIS AND STUDY OF CORROSION PERFORMANCE OF EPOXY COATING CONTAINING MULTI-WALLED CARBON NANOTUBE/ POLY ORTHO AMINOPHENOL NANOCOMPOSITE

    Directory of Open Access Journals (Sweden)

    N. Bahrami Panah

    2016-03-01

    Full Text Available The epoxy coatings containing multi-walled carbon nanotube/ poly ortho aminophenol nanocomposite were prepared and used as anticorrosive coatings. The nanocomposites with different contents of carbon nanotube were synthesized in a solution of sodium dodecyl sulfate and ammonium peroxy disulfate as a surfactant and an oxidant, respectively. The morphology and structural properties were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy methods. The mean size of nanocomposite particles was 20-35 nm determined by scanning electron microscopy. The epoxy coatings containing the nanocomposites were applied over mild steel panels and their corrosion performance was investigated using electrochemical impedance spectroscopy and potentiodynamic polarization measurements in a 3.5 % sodium chloride solution. The results showed that epoxy coatings consisting of nanocomposite with 1 wt.% multi-walled carbon nanotube exhibited higher anticorrosive properties than other prepared coatings of different carbon nanotube contents, which could be due to the strong interaction between the mild steel surface and the conjugated nanocomposite.

  20. Effect of the hardener to epoxy monomer ratio on the water absorption behavior of the DGEBA/TETA epoxy system

    Directory of Open Access Journals (Sweden)

    Ayrton Alef Castanheira Pereira

    2016-02-01

    Full Text Available Abstract The water absorption behavior of the DGEBA/TETA epoxy system was evaluated as a function of the epoxy monomer to amine hardener ratio. Weight gain versus immersion time curves were obtained and the experimental points were fitted using Fickian and Non-Fickian diffusion models. The results obtained showed that for all epoxy monomer to hardener ratios analyzed water diffusion followed non-Fickian behavior. It was possible to correlate the water absorption behavior to the macromolecular structure developed when the epoxy/ hardener ratio was varied. All epoxy/hardener ratios present a two-phase macromolecular structure, composed of regions with high crosslink density and regions with lower crosslinking. Epoxy rich systems have a more open macromolecular structure with a lower fraction of the dense phase than the amine rich systems, which present a more compact two-phase structure.

  1. Morphology and Properties of Geopolymer Coatings on Glass Fibre-Reinforced Epoxy (GRE pipe

    Directory of Open Access Journals (Sweden)

    Shahedan Noor Fifinatasha

    2016-01-01

    Full Text Available Geopolymer coatings were coated on glass fibre-reinforced epoxy (GRE pipe by using kaolin, white clay and silica sand as source materials and sodium hydroxide (NaOH and sodium silicate (Na2SiO3 as alkaline solution. The microstructure and mechanical property of geopolymer coating on GRE pipe were methodically investigated through morphology analysis, and flexural strength test. The result indicates the microstructure and interfacial layer between geopolymer coating and GRE pipe significantly influence the mechanical property of geopolymer coating. However, different source materials gave different microstructure and property in geopolymer coating.

  2. Hierarchically rough, mechanically durable and superhydrophobic epoxy coatings through rapid evaporation spray method

    International Nuclear Information System (INIS)

    Simovich, Tomer; Wu, Alex H.; Lamb, Robert N.

    2015-01-01

    A mechanically durable and scalable superhydrophobic coating was fabricated by combining the advantages of both bottom-up and top-down approaches into a one-pot, one-step application method. This is achieved by spray coating a solution consisting of silica nanoparticles, which are embedded within epoxy resin, onto a heated substrate to rapidly drive both solvent evaporation and curing simultaneously. By maintaining a high substrate temperature, the arrival of spray-delivered micrometer-sized droplets are rapidly cured onto the substrate to form surface microroughness, while simultaneously, rapid solvent evaporation within each droplet results in the formation of a nanoporous structure. SEM, dual-beam FIB, and cross-sectional TEM/EDAX elemental mapping were used to confirm both the chemistry and the requisite micro- and nano-porosity within the coating structure requisite for superhydrophobicity. The resultant coatings exhibit contact angles greater than 150° (153.8° ± 0.8°) and roll-off angles of 8° ± 2°, with a coating hardness of 6H on the pencil hardness scale, and a rating of 5 on an ASTM crosshatch test. - Highlights: • A highly superhydrophobic coating was fabricated utilizing epoxy and nanoparticles. • The coating was demonstrated to be very durable and abrasion resistant. • The fabrication involves a novel, scalable one-pot synthesis technique

  3. Hierarchically rough, mechanically durable and superhydrophobic epoxy coatings through rapid evaporation spray method

    Energy Technology Data Exchange (ETDEWEB)

    Simovich, Tomer; Wu, Alex H.; Lamb, Robert N., E-mail: rnlamb@unimelb.edu.au

    2015-08-31

    A mechanically durable and scalable superhydrophobic coating was fabricated by combining the advantages of both bottom-up and top-down approaches into a one-pot, one-step application method. This is achieved by spray coating a solution consisting of silica nanoparticles, which are embedded within epoxy resin, onto a heated substrate to rapidly drive both solvent evaporation and curing simultaneously. By maintaining a high substrate temperature, the arrival of spray-delivered micrometer-sized droplets are rapidly cured onto the substrate to form surface microroughness, while simultaneously, rapid solvent evaporation within each droplet results in the formation of a nanoporous structure. SEM, dual-beam FIB, and cross-sectional TEM/EDAX elemental mapping were used to confirm both the chemistry and the requisite micro- and nano-porosity within the coating structure requisite for superhydrophobicity. The resultant coatings exhibit contact angles greater than 150° (153.8° ± 0.8°) and roll-off angles of 8° ± 2°, with a coating hardness of 6H on the pencil hardness scale, and a rating of 5 on an ASTM crosshatch test. - Highlights: • A highly superhydrophobic coating was fabricated utilizing epoxy and nanoparticles. • The coating was demonstrated to be very durable and abrasion resistant. • The fabrication involves a novel, scalable one-pot synthesis technique.

  4. ‘Containers’ for self-healing epoxy composites and coating: Trends and advances

    Directory of Open Access Journals (Sweden)

    P. Vijayan

    2016-06-01

    Full Text Available The introduction of self-healing functionality into epoxy matrix is an important and challenging topic. Various micro/nano containers loaded self-healing agents are developed and incorporated into epoxy matrix to impart self-healing ability. The current report reviews the major findings in the area of self-healing epoxy composites and coatings with special emphasis on these containers. The preparation and use of polymer micro/nano capsules, polymer fibers, hollow glass fibers/bubbles, inorganic nanotubes, inorganic meso- and nano-porous materials, carbon nanotubes etc. as self-healing containers are outlined. The nature of the container and its response to the external stimulations greatly influence the self-healing performance. The self-healing mechanism associated with each type of container and the role of container parameters on self-healing performance of self-healing epoxy systems are reviewed. Comparison of the efficiency offered by different types of containers is introduced. Finally, the selection of containers to develop cost effective and green self-healing systems are mentioned.

  5. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Samad, Ubair Abdus [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Khan, Rawaiz [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Alam, Mohammad Asif [Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Al-Othman, Othman Y. [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Deanship of Graduate Studies, The Saudi Electric University, P. O. Box 93499, Riyadh 11673 (Saudi Arabia); Al-Zahrani, Saeed M. [Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); SABIC Polymer Research Center (SPRC) and department of chemical engineering, college of engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia)

    2015-05-22

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.

  6. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    International Nuclear Information System (INIS)

    Samad, Ubair Abdus; Khan, Rawaiz; Alam, Mohammad Asif; Al-Othman, Othman Y.; Al-Zahrani, Saeed M.

    2015-01-01

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale

  7. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    Science.gov (United States)

    Samad, Ubair Abdus; Khan, Rawaiz; Alam, Mohammad Asif; Al-Othman, Othman Y.; Al-Zahrani, Saeed M.

    2015-05-01

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.

  8. Corrosion protection of Mg-5Li alloy with epoxy coatings containing polyaniline

    International Nuclear Information System (INIS)

    Shao Yawei; Huang Hui; Zhang Tao; Meng Guozhe; Wang Fuhui

    2009-01-01

    The protective ability of epoxy coating containing polyaniline (PANI coating) on Mg-5Li alloy in 3.5% NaCl aqueous solution has been studied by means of EIS and electrochemical noise measurements (EN). The results of EN and EIS revealed that the PANI coating protected Mg-5Li alloy from corrosion perfectly. XPS results indicated that the presence of polyaniline changed the chemical structure of the corrosion film on the alloy surface. An analysis of the electrochemical noise data based on stochastic analysis indicated that the corrosion growth probability of Mg-5Li alloy beneath the coating was decreased by the addition of polyaniline.

  9. Protective Performance of Polyaniline-Sulfosalicylic Acid/Epoxy Coating for 5083 Aluminum

    Science.gov (United States)

    Liu, Suyun; Liu, Li; Meng, Fandi; Li, Ying; Wang, Fuhui

    2018-01-01

    Epoxy coatings incorporating different content of sulfosalicylic acid doped polyaniline (PANI-SSA) have been investigated for corrosion protection of 5083 aluminum alloy in 3.5% NaCl solution. The performance of the coatings is studied using a combination of electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), gravimetric tests, adhesion tests, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the content of PANI-SSA not only affects the coating compactness and the transportation of aggressive medium, but also has a significant influence on the-based aluminum. The coating with 2 wt. % PANI-SSA exhibits the best corrosion inhibition due to its good protective properties and the formation of a complete PANI-SSA induced oxide layer. PMID:29438304

  10. Interpretation of Mechanical and Thermal Properties of Heavy Duty Epoxy Based Floor Coating Doped by Nanosilica

    Science.gov (United States)

    Nikje, M. M. Alavi; Khanmohammadi, M.; Garmarudi, A. Bagheri

    Epoxy-nano silica composites were prepared using Bisphenol-A epoxy resin (Araldite® GY 6010) resin obtained from in situ polymerization or blending method. SiO2 nanoparticles were pretreated by a silan based coupling agent. Surface treated nano silica was dispersed excellently by mechanical and ultrasonic homogenizers. A dramatic increase in the interfacial area between fillers and polymer can significantly improve the properties of the epoxy coating product such as tensile, elongation, abrasion resistance, etc.

  11. The Effect of Substrate Contaminates on the Life of Epoxy Coatings Submerged in Sea Water

    Science.gov (United States)

    1991-03-01

    contaminants: coal tar, SovaPon, Mare Island and Aquapon . Aquapon is a clear (unpigmented) polyamide epoxy coating. While Aquapon is not normally used for...pigmented coatings. It was found that the Aquapon and coal tar coatings performed similarly, and blistered to the same extent, at the contamination levels...used in the test program. The Sovapon and Mare Island coatings were slightly more resistive to blistering when compared to Aquapon or coal tar but they

  12. A biomimetic approach to enhancing interfacial interactions: polydopamine-coated clay as reinforcement for epoxy resin.

    Science.gov (United States)

    Yang, Liping; Phua, Si Lei; Teo, Jun Kai Herman; Toh, Cher Ling; Lau, Soo Khim; Ma, Jan; Lu, Xuehong

    2011-08-01

    A facile biomimetic method was developed to enhance the interfacial interaction in polymer-layered silicate nanocomposites. By mimicking mussel adhesive proteins, a monolayer of polydopamine was constructed on clay surface by a controllable coating method. The modified clay (D-clay) was incorporated into an epoxy resin, it is found that the strong interfacial interactions brought by the polydopamine benefits not only the dispersion of the D-clay in the epoxy but also the effective interfacial stress transfer, leading to greatly improved thermomechanical properties at very low inorganic loadings. Rheological and infrared spectroscopic studies show that the interfacial interactions between the D-clay and epoxy are dominated by the hydrogen bonds between the catechol-enriched polydopamine and the epoxy.

  13. Corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by a sol-gel based silane coating filled with amino and isocyanate silane functionalized graphene oxide nanosheets

    Science.gov (United States)

    Parhizkar, Nafise; Ramezanzadeh, Bahram; Shahrabi, Taghi

    2018-05-01

    This research has focused on the effect of graphene oxide (GO) nano-fillers embedded in the sol-gel based silane coating on the corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by silane coatings. For this purpose, a mixture of Methyltriethoxysilane (MTES) and Tetraethylorthosilicate (TEOS) silane precursors was used for preparation of composite matrix and the GO nanosheets, which are covalently functionalized with 3-(Triethoxysilyl)propyl isocyanate (TEPI, IGO nano-fillers) and 3-aminopropyltriethoxysilane (APTES, AGO nano-fillers), were used as filler. The GO, AGO and IGO nanosheets were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible analysis and field emission-scanning electron microscopy techniques. The performance of the silane/epoxy coatings was investigated by pull-off adhesion, cathodic delamination, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results revealed that AGO and IGO nano-fillers significantly improved the corrosion resistance and adhesion properties of the top epoxy coating due to better compatibility with silane matrix, excellent barrier properties and the formation of covalent bonds with the top epoxy coating.

  14. The Effect of Nanoparticles Percentage on Mechanical Behavior of Silica-Epoxy Nanocomposites

    International Nuclear Information System (INIS)

    Islam, M.S.; Masoodi, R.; Rostami, H.

    2013-01-01

    Silica-epoxy nanocomposites are very common among nanocomposites, which makes them very important. Several researchers have studied the effect of nanoparticle’s size, shape, and loading on mechanical behavior of silica-epoxy nanocomposites. This paper reviews the most important research done on the effect of nanoparticle loading on mechanical properties of silica-epoxy nanocomposites. While the main focus is the tensile behavior of nanocomposite, the compressive behavior and flexural behavior were also reviewed. Finally, some of the published experimental data were combined in the graphs, using dimensionless parameters. Later, the best fitted curves were used to derive some empirical formulas for mechanical properties of silica-epoxy nanocomposites as functions of weight or volume fraction of nanoparticles.

  15. Three-dimensional (3D) plasma micro-nanotextured slides for high performance biomolecule microarrays: Comparison with epoxy-silane coated glass slides.

    Science.gov (United States)

    Tsougeni, Katerina; Ellinas, Kosmas; Koukouvinos, George; Petrou, Panagiota S; Tserepi, Angeliki; Kakabakos, Sotirios E; Gogolides, Evangelos

    2018-05-01

    Glass slides coated with a poly(methyl methacrylate) layer and plasma micro-nanotextured to acquire 3D topography (referred as 3D micro-nanotextured slides) were evaluated as substrates for biomolecule microarrays. Their performance is compared with that of epoxy-coated glass slides. We found that the proposed three-dimensional (3D) slides offered significant improvements in terms of spot intensity, homogeneity, and reproducibility. In particular, they provided higher spot intensity, by a factor of at least 1.5, and significantly improved spot homogeneity when compared to the epoxy-silane coated ones (intra-spot and between spot coefficients of variation ranging between 5 and 15% for the 3D micro-nanotextured slides and between 25 and 85% for the epoxy-silane coated ones). The latter was to a great extent the result of a strong "coffee-ring" effect observed for the spots created on the epoxy-coated slides; a phenomenon that was severely reduced in the 3D micro-nanotextured slides. The 3D micro-nanotextured slides offered in addition higher signal to noise ratio values over a wide range of protein probe concentrations and shelf-life over one year without requirement for specific storage conditions. Finally, the protocols employed for protein probe immobilization were extremely simple. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Fracture behavior of α-zirconium phosphate-based epoxy nanocomposites

    International Nuclear Information System (INIS)

    Sue, H.-J.; Gam, K.T.; Bestaoui, N.; Clearfield, A.; Miyamoto, M.; Miyatake, N.

    2004-01-01

    The fracture behaviors of α-zirconium phosphate (α-ZrP) based epoxy nanocomposites, with and without core-shell rubber (CSR) toughening, were investigated. The state of exfoliation and dispersion of α-ZrP nanofiller in epoxy were characterized using X-ray scattering and various microscopy tools. The level of enhancement in storage moduli of epoxy nanocomposite against neat epoxy is found to depend on the state of exfoliation of α-ZrP as well as the damping characteristics of the epoxy matrix. The fracture process in epoxy nanocomposite is dominated by preferred crack propagation along the weak intercalated α-ZrP interfaces, and the presence of α-ZrP does not alter the fracture toughness of the epoxy matrix. However, the toughening using CSR can significantly improve the fracture toughness of the nanocomposite. The fracture mechanisms responsible for such a toughening effect in CSR-toughened epoxy nanocomposite are rubber particle cavitation, followed by shear banding of epoxy matrix. The ductility and toughenability of epoxy do not appear to be affected by the incorporation of α-ZrP. Approaches for producing toughened high performance polymer nanocomposites are discussed

  17. Electrochemical corrosion behavior of carbon steel with bulk coating holidays

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    With epoxy coal tar as the coating material, the electrochemical corrosion behavior of Q235 with different kinds of bulk coating holidays has been investigated with EIS (Electrochemical Impedance Spectroscopy) in a 3.5vol% NaCl aqueous solution.The area ratio of bulk coating holiday to total coating area of steel is 4.91%. The experimental results showed that at free corrosionpotential, the corrosion of carbon steel with disbonded coating holiday is heavier than that with broken holiday and disbonded & broken holiday with time; Moreover, the effectiveness of Cathodic Protection (CP) of carbon steel with broken holiday is better than that with disbonded holiday and disbonded & broken holiday on CP potential -850 mV (vs CSE). Further analysis indicated that the two main reasons for corrosion are electrolyte solution slowly penetrating the coating, and crevice corrosion at steel/coating interface near holidays. The ratio of impedance amplitude (Z) of different frequency to minimum frequency is defined as K value. The change rate of K with frequency is related to the type of coating holiday.

  18. New method for determination of epichlorohydrin in epoxy-coated cans by oxolane derivatization and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Sung, Jun Hyun; Lee, Young Ja; Park, Hyun Jin

    2008-08-01

    A new method was developed for the determination of epichlorohydrin (ECH) in food contact surface of epoxy-coated cans. The oxolane derivative, which produced by reaction of epoxy moiety in ECH with cyclopentanone in the presence of borontrifluoride-diethyletherate, was analyzed by gas chromatography (GC)/mass spectrometry (MS). 1,2-Epoxyhexane was used as internal standard (IS), which produced an oxolane derivative under the same reaction mechanism as ECH. The developed method was validated with 1 ng ml(-1) of limit of detection (LOD, surface area related 20 ng dm(-2)), >0.999 of linearity. Good precision, which was tested both in terms of intra-day repeatability and inter-day reproducibility, and 97.3-102.7% of good recoveries were obtained on three spiked levels of 5.2, 40.3 and 149.1 ng ml(-1). The excellent validation data suggests that this method is more simple, quick and effective than the official method in European Committee for Standardization (CEN) to determine the residual amount of ECH in food contact materials for food law compliance test. The residual amount of ECH for 13 epoxy-coated can samples was analyzed, and none of the samples was found to be detectable levels of ECH in epoxy-coated cans.

  19. Investigation of parameters governing the corrosion protection efficacy of fusion bonded epoxy coatings

    OpenAIRE

    Ramniceanu, Andrei

    2007-01-01

    The primary cause of corrosion in transportation structures is due to chlorides which are applied to bridge decks as deicing salts. The direct cost of corrosion damage to the countryâ s infrastructure is approximately $8.3 billion per year. One of the most common corrosion abatement methods in the United States is the barrier protection implemented through the application of fusion bonded epoxy coatings. The purpose of this study was to investigate various coating and exposure param...

  20. Influence of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires

    Science.gov (United States)

    Asiry, Moshabab A.; AlShahrani, Ibrahim; Almoammar, Salem; Durgesh, Bangalore H.; Kheraif, Abdulaziz A. Al; Hashem, Mohamed I.

    2018-02-01

    Aim. To investigate the effect of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires Methods. Three different coated (Epoxy, polytetrafluoroethylene (PTFE) and rhodium) and one uncoated Ni-Ti archwires were evaluated in the present study. Surface roughness (Ra) was assessed using a non-contact surface profilometer. The mechanical properties (nano-hardness and elastic modulus) were measured using a nanoindenter. Bacterial adhesion assays were performed using Streptococcus mutans (MS) and streptococcus sobrinus (SS) in an in-vitro set up. The data obtained were analyzed using analyses of variance, Tukey’s post hoc test and Pearson’s correlation coefficient test. Result. The highest Ra values (1.29 ± 0.49) were obtained for epoxy coated wires and lowest Ra values (0.29 ± 0.16) were obtained for the uncoated wires. No significant differences in the Ra values were observed between the rhodium coated and uncoated archwires (P > 0.05). The highest nano-hardness (3.72 ± 0.24) and elastic modulus values (61.15 ± 2.59) were obtained for uncoated archwires and the lowest nano-hardness (0.18 ± 0.10) and elastic modulus values (4.84 ± 0.65) were observed for epoxy coated archwires. No significant differences in nano-hardness and elastic modulus values were observed between the coated archwires (P > 0.05). The adhesion of Streptococcus mutans (MS) to the wires was significantly greater than that of streptococcus sobrinus (SS). The epoxy coated wires demonstrated an increased adhesion of MS and SS and the uncoated wires demonstrated decreased biofilm adhesion. The Spearman correlation test showed that MS and SS adhesion was positively correlated with the surface roughness of the wires. Conclusion. The different surface coatings significantly influence the roughness, nano-mechanical properties and biofilm adhesion parameters of the archwires. The

  1. Thermomechanical Behavior of High Performance Epoxy/Organoclay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Artur Soares Cavalcanti Leal

    2014-01-01

    Full Text Available Nanocomposites of epoxy resin containing bentonite clay were fabricated to evaluate the thermomechanical behavior during heating. The epoxy resin system studied was prepared using bifunctional diglycidyl ether of bisphenol A (DGEBA, crosslinking agent diaminodiphenylsulfone (DDS, and diethylenetriamine (DETA. The purified bentonite organoclay (APOC was used in all experiments. The formation of nanocomposite was confirmed by X-ray diffraction analysis. Specimens of the fabricated nanocomposites were characterized by dynamic mechanical analysis (DMA. According to the DMA results a significant increase in glass transition temperature and storage modulus was evidenced when 1 phr of clay is added to epoxy resin.

  2. Evaluation of the corrosion resistance of an epoxy-polyamide coating containing different ratios of micaceous iron oxide/Al pigments

    International Nuclear Information System (INIS)

    Nikravesh, B.; Ramezanzadeh, B.; Sarabi, A.A.; Kasiriha, S.M.

    2011-01-01

    Research highlights: → The corrosion resistance of the coating was improved using MIO and Al pigments. → The greatest coating corrosion resistance was observed at MIO/Al ratio of 10/90. → The cathodic disbonded area of the coating was decreased using MIO and Al particles. → The lowest disbonded area was observed at MIO/Al ratio of 10/90. → Al particles had high capability of reacting with the OH - ions. - Abstract: The corrosion resistance of an epoxy coating reinforced with different ratios of MIO/Al pigments was studied. The coatings properties were investigated by an electrochemical impedance spectroscopy (EIS), salt spray test, cathodic disbonding and a scanning electron microscope (SEM). The corrosion resistance of the epoxy coating was improved using MIO (micaceous iron oxide) and Al pigments. The corrosion resistance of the purely Al pigmented coating was considerably greater than the purely MIO pigmented coating. The cathodic disbonded area of coating was decreased using MIO and Al pigments. The decrease in disbonded area was more pronounced in the presence of Al particles.

  3. MECHANICAL PROPERTIES AND CORROSION PROTECTION OF CARBON STEEL COATED WITH AN EPOXY BASED POWDER COATING CONTAINING MONTMORILONITE FUNCTIONALIZED WITH SILANE

    OpenAIRE

    Paula Tibola Bertuoli; Veronica Perozzo Frizzo; Diego Piazza; Lisete Cristine Scienza; Ademir José Zattera

    2014-01-01

    In the present work the MMT-Na+ clay was functionalized with 3-aminopropyltriethoxysilane (γ-APS) and incorporated in a commercial formulation epoxy-based powder coating in a proportion of 8 wt% and applied on 1008 carbon steel panels by electrostatic spray. Adhesion, flexibility, impact and corrosion performance in salt spray chamber tests were performed to evaluate the coatings. The presence of clay did not affect the mechanical properties of the film, however greater subcutaneo...

  4. Enhanced lifetime characteristics in flexible polymer light-emitting devices by encapsulation of epoxy/silica-coated gold nanoparticles resin (ESGR)

    International Nuclear Information System (INIS)

    Chiu, Pin-Hsiang; Huang, Chien-Jung; Yang, Cheng-Fu; Meen, Teen-Hang; Wang, Yeong-Her

    2010-01-01

    This paper reports the effects of a new multilayer encapsulation for the lifetime of flexible PLEDs on plastic substrate. The multilayer encapsulation consisted of a novel epoxy/silica-coated gold nanoparticles resin (ESGR) as the pre-encapsulation layer and a SiO 2 layer as the encapsulation cap. The ESGR was prepared by mixing UV-curable epoxy resin and powders of silica-coated gold nanoparticles. The silica-coated gold nanoparticles is a necessity because the epoxy resin is not a good moisture barrier. The flexible PLEDs with multilayer encapsulation exhibited no dark spots after being stored for over 300 h at 25 deg. C and 60% relative humidity. Also, the operational half-luminance decay time of device was 1360 h, seven times longer than that of a device without encapsulation. These results confirmed that the multilayer encapsulation, which restricted the moisture that penetrated into the devices, could be applied to the encapsulation of flexible PLEDs.

  5. Coating of carbon nanotube fibers: variation of tensile properties, failure behavior and adhesion strength

    Directory of Open Access Journals (Sweden)

    Edith eMäder

    2015-07-01

    Full Text Available An experimental study of the tensile properties of CNT fibers and their interphasial behavior in epoxy matrices is reported. One of the most promising applications of CNT fibers is their use as reinforcement in multifunctional composites. For this purpose, an increase of the tensile strength of the CNT fibers in unidirectional composites as well as strong interfacial adhesion strength is desirable. However, the mechanical performance of the CNT fiber composites manufactured so far is comparable to that of commercial fiber composites. The interfacial properties of CNT fiber/polymer composites have rarely been investigated and provided CNT fiber/epoxy interfacial shear strength of 14.4 MPa studied by the microbond test.In order to improve the mechanical performance of the CNT fibers, an epoxy compatible coating with nano-dispersed aqueous based polymeric film formers and low viscous epoxy resin, respectively, was applied. For impregnation of high homogeneity, low molecular weight epoxy film formers and polyurethane film formers were used. The aqueous based epoxy film formers were not crosslinked and able to interdiffuse with the matrix resin after impregnation. Due to good wetting of the individual CNT fibers by the film formers, the degree of activation of the fibers was improved leading to increased tensile strength and Young’s modulus. Cyclic tensile loading and simultaneous determination of electric resistance enabled to characterize the fiber’s durability in terms of elastic recovery and hysteresis.The pull-out tests and SEM study reveal different interfacial failure mechanisms in CNT fiber/epoxy systems for untreated and film former treated fibers, on the one hand, and epoxy resin treated ones, on the other hand. The epoxy resin penetrated between the CNT bundles in the reference or film former coated fiber, forming a relatively thick CNT/epoxy composite layer and thus shifting the fracture zone within the fiber. In contrast to this

  6. Properties of a epoxy-based powder coating containing modified montmorillonite with cerium

    International Nuclear Information System (INIS)

    Beux, A.R.D.; Piazza, D.; Zattera, A.J.; Ferreira, C.A.; Scienza, L.C.

    2014-01-01

    Organic coatings are widely used to prevent corrosion in metal structures. The incorporation of nanofiller the polymer matrix in order to obtain polymer nanocomposites has been arousing scientific and technological interest, because it provides significant improvements when incorporated into pure polymeric materials or conventional composites. In the present study were been developed epoxy-based powder coating with addition of different concentrations (2, 4 and 8% (w / w)) of the montmorillonite type Cloisite® 15A modified with cerium in the melt state on a double-screw extruder co-rotating. The coatings were characterized by average particle size, time (gel time) gel, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Coatings with intercalated structure was observed in the XRD analysis and confirmed by SEM to the observe an increase in the concentration of tactoids an increased filler content. (author)

  7. Silica Treatments: A Fire Retardant Strategy for Hemp Fabric/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Francesco Branda

    2016-08-01

    Full Text Available In this paper, for the first time, inexpensive waterglass solutions are exploited as a new, simple and ecofriendly chemical approach for promoting the formation of a silica-based coating on hemp fabrics, able to act as a thermal shield and to protect the latter from heat sources. Fourier Transform Infrared (FTIR and solid-state Nuclear Magnetic Resonance (NMR analysis confirm the formation of –C–O–Si– covalent bonds between the coating and the cellulosic substrate. The proposed waterglass treatment, which is resistant to washing, seems to be very effective for improving the fire behavior of hemp fabric/epoxy composites, also in combination with ammonium polyphosphate. In particular, the exploitation of hemp surface treatment and Ammonium Polyphosphate (APP addition to epoxy favors a remarkable decrease of the Heat Release Rate (HRR, Total Heat Release (THR, Total Smoke Release (TSR and Specific Extinction Area (SEA (respectively by 83%, 35%, 45% and 44% as compared to untreated hemp/epoxy composites, favoring the formation of a very stable char, as also assessed by Thermogravimetric Analysis (TGA. Because of the low interfacial adhesion between the fabrics and the epoxy matrix, the obtained composites show low strength and stiffness; however, the energy absorbed by the material is higher when using treated hemp. The presence of APP in the epoxy matrix does not affect the mechanical behavior of the composites.

  8. Cationic Reduced Graphene Oxide as Self-Aligned Nanofiller in the Epoxy Nanocomposite Coating with Excellent Anticorrosive Performance and Its High Antibacterial Activity.

    Science.gov (United States)

    Luo, Xiaohu; Zhong, Jiawen; Zhou, Qiulan; Du, Shuo; Yuan, Song; Liu, Yali

    2018-05-17

    The design and preparation of an excellent corrosion protection coating is still a grand challenge and is essential for large-scale practical application. Herein, a novel cationic reduced graphene oxide (denoted as RGO-ID + )-based epoxy coating was fabricated for corrosion protection. RGO-ID + was synthesized by in situ synthesis and salification reaction, which is stable dispersion in water and epoxy latex, and the self-aligned RGO-ID + -reinforced cathodic electrophoretic epoxy nanocomposite coating (denoted as RGO-ID + coating) at the surface of metal was prepared by electrodeposition. The self-alignment of RGO-ID + in the coatings is mainly attributed to the electric field force. The significantly enhanced anticorrosion performance of RGO-ID + coating is proved by a series of electrochemical measurements in different concentrated NaCl solutions and salt spray tests. This superior anticorrosion property benefits from the self-aligned RGO-ID + nanosheets and the quaternary-N groups present in the RGO-ID + nanocomposite coating. Interestingly, the RGO-ID + also exhibits a high antibacterial activity toward Escherichia coli with 83.4 ± 1.3% antibacterial efficiency, which is attributed to the synergetic effects of RGO-ID + and the electrostatic attraction and hydrogen bonding between RGO-ID + and E. coli. This work offers new opportunities for the successful development of effective corrosion protection and self-antibacterial coatings.

  9. Microwave electromagnetic properties of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coating

    International Nuclear Information System (INIS)

    Qing Yuchang; Zhou Wancheng; Luo Fa; Zhu Dongmei

    2010-01-01

    The electromagnetic characteristics of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coatings were studied. The reflection loss of the coatings exceeds -10 dB at 8-18 GHz and -9 dB at 2-18 GHz when the coating thickness is 1 and 3 mm, respectively. The dielectric and magnetic absorbers filled coatings possess excellent microwave absorption, which could be attributed to the proper incorporate of the multi-polarization mechanisms as well as strong natural resonance. It is feasible to develop the thin and wideband microwave absorbing coatings using carbonyl iron particles and Si/C/N nano-powder.

  10. Microwave electromagnetic properties of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coating

    Science.gov (United States)

    Qing, Yuchang; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

    2010-02-01

    The electromagnetic characteristics of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coatings were studied. The reflection loss of the coatings exceeds -10 dB at 8-18 GHz and -9 dB at 2-18 GHz when the coating thickness is 1 and 3 mm, respectively. The dielectric and magnetic absorbers filled coatings possess excellent microwave absorption, which could be attributed to the proper incorporate of the multi-polarization mechanisms as well as strong natural resonance. It is feasible to develop the thin and wideband microwave absorbing coatings using carbonyl iron particles and Si/C/N nano-powder.

  11. Nonlinear DC Conduction Behavior in Graphene Nanoplatelets/Epoxy Resin Composites

    Science.gov (United States)

    Yuan, Yang; Wang, Qingguo; Qu, Zhaoming

    2018-01-01

    Graphene nanoplatelets (GNPs)/Epoxy resin (ER) with a low percolation threshold were fabricated. Then the nonlinear DC conduction behavior of GNPs/ER composites was investigated, which indicates that dispersion, exfoliation level and conductivity of GNPs in specimens are closely related to the conduction of composites. Moreover, it could be seen that the modified graphene nanoplatelets made in this paper could be successfully used for increasing the electric conductivity of the epoxy resin, and the GNPs/ER composites with nonlinear conduction behavior have a good application prospects in the field of intelligent electromagnetic protection.

  12. Characterizations of biodegradable epoxy-coated cellulose nanofibrils (CNF) thin film for flexible microwave applications

    Science.gov (United States)

    Hongyi Mi; Chien-Hao Liu; Tzu-Husan Chang; Jung-Hun Seo; Huilong Zhang; Sang June Cho; Nader Behdad; Zhenqiang Ma; Chunhua Yao; Zhiyong Cai; Shaoqin Gong

    2016-01-01

    Wood pulp cellulose nanofibrils (CNF) thin film is a novel recyclable and biodegradable material. We investigated the microwave dielectric properties of the epoxy coated-CNF thin film for potential broad applications in flexible high speed electronics. The characterizations of dielectric properties were carried out in a frequency range of 1–10 GHz. The dielectric...

  13. MECHANICAL PROPERTIES AND CORROSION PROTECTION OF CARBON STEEL COATED WITH AN EPOXY BASED POWDER COATING CONTAINING MONTMORILONITE FUNCTIONALIZED WITH SILANE

    Directory of Open Access Journals (Sweden)

    Paula Tibola Bertuoli

    2014-06-01

    Full Text Available In the present work the MMT-Na+ clay was functionalized with 3-aminopropyltriethoxysilane (γ-APS and incorporated in a commercial formulation epoxy-based powder coating in a proportion of 8 wt% and applied on 1008 carbon steel panels by electrostatic spray. Adhesion, flexibility, impact and corrosion performance in salt spray chamber tests were performed to evaluate the coatings. The presence of clay did not affect the mechanical properties of the film, however greater subcutaneous migration was assessed after the completion of salt spray testing, which can compromise the use of paints obtained as primers.

  14. Synthesis of polyoxometalate-loaded epoxy composites

    Science.gov (United States)

    Anderson, Benjamin J

    2014-10-07

    The synthesis of a polyoxometalate-loaded epoxy uses a one-step cure by applying an external stimulus to release the acid from the polyoxometalate and thereby catalyze the cure reaction of the epoxy resin. Such polyoxometalate-loaded epoxy composites afford the cured epoxy unique properties imparted by the intrinsic properties of the polyoxometalate. For example, polyoxometalate-loaded epoxy composites can be used as corrosion resistant epoxy coatings, for encapsulation of electronics with improved dielectric properties, and for structural applications with improved mechanical properties.

  15. Preparation and performance evaluation of epoxy-based heat reflective coating for the pavement

    Science.gov (United States)

    Hu, B.; Liang, Y. H.; Guo, L. Y.; Jiang, T.

    2017-04-01

    According to the basic characteristics and composition of heat-reflective coating, combining with the functional requirements of road materials, the experiment selects the epoxy resin with good wear resistance and adhesive force as a film forming material, with TiO2, SiO2 and extinction powder as the main functional filler. The experiment gets a good formula with suitable viscosity, low glossiness and good cooling effect, optimizes by orthogonal experiment. The experiment evaluates the indoor and outdoor cooling effect of heat-reflective coating, and analyses the road performance of the coating. The results shows that the better heat-reflective coating formula included 12% of titanium dioxide, 4% of silica and 4% of extinction powder. When the dosage of coating is 0.8kg/m2, the indoor specimen of heat-reflective coating decrease the temperature of 12 ˜ 14°C, and the specimen under solar radiation can reduce the temperature of 7 ˜ 9°C. The pavement of heat-reflective coating has good wear resistance, but the road slip resistance partly declines. Therefore, it needs to add the anti-sliding particles to meet the safe driving requirements.

  16. Corrosion protection and delamination mechanism of epoxy/carbon black nanocomposite coating on AA2024-T3

    NARCIS (Netherlands)

    Foyet, A.; Wu, T.H.; Kodentsov, A.; Ven, van der L.G.J.; With, de G.; Benthem, van R.A.T.M.

    2013-01-01

    The barrier property of a nanocomposite epoxy coating containing 1 or 1.25 vol% of carbon black (CB) applied on AA2024-T3 was investigated by using electrochemical impedance spectroscopy. Micro-electrochemical impedance spectroscopy and optical microscopy were also used to investigate the

  17. Corrosion Behavior of Three Nanoclay Dispersion Methods of Epoxy/Organoclay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Wiwat Keyoonwong

    2012-01-01

    Full Text Available The aims of this study, firstly, to obtain high degree of clay exfoliation in the epoxy matrix by three dispersion methods such as normal mixing, shear mixing, and high-speed mixing and, secondly, to investigate corrosion behavior of epoxy/organoclay nanocomposite, immersion test, weight change, and penetration behavior were conducted. From the three mixing methods, the high-speed mixing method showed larger clay interlayer distance, smaller clay aggregate, and more homogeneity and expectedly resulted in high anticorrosive properties. Penetration depths of these nanocomposites showed a small difference; however, the most noticeable improvements in anticorrosion performance for epoxy/organoclay nanocomposites under high-speed mixing method were found to reduce penetration and weight uptake which are described via the model of nanoparticulate-filled structure and discussed in corrosion protection mechanism against environmental liquid penetration.

  18. Magnetoelectric behavior of carbonyl iron mixed Mn oxide-coated ferrite nanoparticles

    Science.gov (United States)

    Ahad, Faris B. Abdul; Lee, Shang-Fan; Hung, Dung-Shing; Yao, Yeong-Der; Yang, Ruey-Bin; Lin, Chung-Kwei; Tsay, Chien-Yie

    2010-05-01

    The dielectric and magnetic properties of manganese oxide-coated Fe3O4 nanoparticles (NPs) were measured by the cavity perturbation method at x-band microwave frequencies ranging from 7-12.5 GHz with controlled external magnetic field up to 2.2 kOe at room temperature. Different ratios (5%, 10%, and 20% by weight) of coated NPs were prepared by sol-gel method then mixed with carbonyl iron powder in epoxy matrix. The saturation magnetization is inversely proportional to the NPs ratio in the mixture between 150 and 180 emu/g. The real part of the permittivity decreased with increasing NPs concentration, but the permittivity change by magnetic field increased. The tunability behavior is explained by insulator-ferromagnetic interface magnetoelectricity and the large surface volume ratio for the NPs.

  19. The Effects of Thermophysical Properties and Environmental Conditions on Fire Performance of Intumescent Coatings on Glass Fibre-Reinforced Epoxy Composites.

    Science.gov (United States)

    Kandola, Baljinder K; Luangtriratana, Piyanuch; Duquesne, Sophie; Bourbigot, Serge

    2015-08-11

    Intumescent coatings are commonly used as passive fire protection systems for steel structures. The purpose of this work is to explore whether these can also be used effectively on glass fibre-reinforced epoxy (GRE) composites, considering the flammability of the composites compared to non-flammable steel substrate. The thermal barrier and reaction-to-fire properties of three commercial intumescent coatings on GRE composites have been studied using a cone calorimeter. Their thermophysical properties in terms of heating rate and/or temperature dependent char expansion ratios and thermal conductivities have been measured and correlated. It has been suggested that these two parameters can be used to design coatings to protect composite laminates of defined thicknesses for specified periods of time. The durability of the coatings to water absorption, peeling, impact, and flexural loading were also studied. A strong adhesion between all types of coatings and the substrate was observed. Water soaking had a little effect on the fire performance of epoxy based coatings. All types of 1 mm thick coatings on GRE helped in retaining ~90% of the flexural property after 2 min exposure to 50 kW/m² heat flux whereas the uncoated laminate underwent severe delamination and loss in structural integrity after 1 min.

  20. The Effects of Thermophysical Properties and Environmental Conditions on Fire Performance of Intumescent Coatings on Glass Fibre-Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Baljinder K. Kandola

    2015-08-01

    Full Text Available Intumescent coatings are commonly used as passive fire protection systems for steel structures. The purpose of this work is to explore whether these can also be used effectively on glass fibre-reinforced epoxy (GRE composites, considering the flammability of the composites compared to non-flammable steel substrate. The thermal barrier and reaction-to-fire properties of three commercial intumescent coatings on GRE composites have been studied using a cone calorimeter. Their thermophysical properties in terms of heating rate and/or temperature dependent char expansion ratios and thermal conductivities have been measured and correlated. It has been suggested that these two parameters can be used to design coatings to protect composite laminates of defined thicknesses for specified periods of time. The durability of the coatings to water absorption, peeling, impact, and flexural loading were also studied. A strong adhesion between all types of coatings and the substrate was observed. Water soaking had a little effect on the fire performance of epoxy based coatings. All types of 1 mm thick coatings on GRE helped in retaining ~90% of the flexural property after 2 min exposure to 50 kW/m2 heat flux whereas the uncoated laminate underwent severe delamination and loss in structural integrity after 1 min.

  1. Architectural optimization of an epoxy-based hybrid sol–gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Murillo-Gutiérrez, N.V., E-mail: murillo@chimie.ups-tlse.fr [Université de Toulouse UPS-INP-CNRS, Institut Carnot CIRIMAT, Toulouse (France); Ansart, F.; Bonino, J-P. [Université de Toulouse UPS-INP-CNRS, Institut Carnot CIRIMAT, Toulouse (France); Kunst, S.R.; Malfatti, C.F. [Universidade Federal do Rio grande do Sul, Laboratory of Corrosion Research (LAPEC), Porto Alegre (Brazil)

    2014-08-01

    An epoxy-based hybrid sol–gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol–gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol–gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

  2. Architectural optimization of an epoxy-based hybrid sol-gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    Science.gov (United States)

    Murillo-Gutiérrez, N. V.; Ansart, F.; Bonino, J.-P.; Kunst, S. R.; Malfatti, C. F.

    2014-08-01

    An epoxy-based hybrid sol-gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol-gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol-gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

  3. Architectural optimization of an epoxy-based hybrid sol–gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    International Nuclear Information System (INIS)

    Murillo-Gutiérrez, N.V.; Ansart, F.; Bonino, J-P.; Kunst, S.R.; Malfatti, C.F.

    2014-01-01

    An epoxy-based hybrid sol–gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol–gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol–gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

  4. Dual functions of imidazole-based polymeric ionic liquid (PIL) on the anticorrosive performance of graphene-based waterborne epoxy coatings

    Science.gov (United States)

    Liu, Chengbao; Du, Peng; Nan, Feng; Zhao, Haichao; Wang, Liping

    2018-06-01

    Dispersion of graphene nanosheets in a water and polymer matrix has been rarely achieved due to graphene’s hydrophobicity, which thus impedes its potential anticorrosive application. In this study, stable graphene aqueous dispersion was obtained by using imidazole-based polymeric ionic liquid (PIL) as the dispersant with ultrasonic vibration. Stacked graphene sheets were exfoliated to a few layers via cation-π interaction between PIL and graphene nanosheets. Electrochemical impedance measurements were taken to investigate the anticorrosion performance of epoxy coatings with or without polymeric ionic liquid–graphene (PIL–G) hybrids. Results indicated that the PIL–G hybrid significantly enhanced the long-term protective performance of epoxy coatings, which was attributed to the synergistic effects of the corrosion-inhibitive PIL and impermeable graphene nanosheets.

  5. Leveling coatings for reducing the atomic oxygen defect density in protected graphite fiber epoxy composites

    Science.gov (United States)

    Jaworske, D. A.; Degroh, Kim K.; Podojil, G.; McCollum, T.; Anzic, J.

    1992-11-01

    Pinholes or other defect sites in a protective oxide coating provide pathways for atomic oxygen in low Earth orbit to reach underlying material. One concept of enhancing the lifetime of materials in low Earth orbit is to apply a leveling coating to the material prior to applying any reflective and protective coatings. Using a surface tension leveling coating concept, a low viscosity epoxy was applied to the surface of several composite coupons. A protective layer of 1000 A of SiO2 was deposited on top of the leveling coating, and the coupons were exposed to an atomic oxygen environment in a plasma asher. Pinhole populations per unit area were estimated by counting the number of undercut sites observed by scanning electron microscopy. Defect density values of 180,000 defects/sq cm were reduced to about 1000 defects/sq cm as a result of the applied leveling coating. These improvements occur at a mass penalty of about 2.5 mg/sq cm.

  6. The novel silicon-containing epoxy/PEPA phosphate flame retardant for transparent intumescent fire resistant coating

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yanchao [School of Materials Science and Engineering, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Wang, Guojian, E-mail: wanggj@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, 4800 Cao' an Road, Shanghai 201804 (China)

    2016-11-01

    Highlights: • The novel halogen-free flame retardant containing silicon and caged bicyclic phosphate was synthesized. • A novel transparent intumescent fire resistant coating was developed by the P-Si synergistic flame retardant and melamine formaldehyde resin. • Excellent fire protection of the transparent intumescent fire resistant coating. • The P-Si synergistic flame retardant could improve the thermo-oxidation resistance of transparent fire resistant coating. - Abstract: A series of novel silicon-containing epoxy/PEPA phosphate flame retardants (EPPSi) were synthesized by polyphosphoric acid (PPA), caged bicyclic phosphate 1-oxo-4-hydroxymethyl-2,6,7-trioxa-L-phosphabicyclo [2.2.2] octane (PEPA), and different ratios of silicon-containing epoxy 1,1,3,3-tetramethyl-1,3-bis(3-(oxiran-2-ylmethoxy)propyl)disiloxane (TMSEP) to 1,4-butanediol diglycidyl ether (BDE). The chemical structure of EPPSi was confirmed by Fourier transform infrared spectroscopy (FTIR) and {sup 1}H nuclear magnetic resonance spectroscopy ({sup 1}H NMR). Afterwards, the transparent intumescent fire resistant coatings were prepared by mixing EPPSi and melamine formaldehyde resin. The influence of silicon on the fire protection of coatings was intensively investigated by fire protection test, intumescence ratio, scanning electron microscope (SEM), compressive strength test, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and real-time FTIR. It was found that the fire resistant coatings obtained the best fire protection when the ratio of TMESP/BDE was 20/100, while excessive TMSEP made the fire protection of coatings deceased sharply. The intumescence ratio, compressive strength test and SEM result showed that a synergistic effect existed between phosphorus and silicon, which improved the foam structure and compressive strength of the char layer significantly. XPS result proved the out-migration effect of silicon. The high concentration silicon on surface played

  7. Laboratory and gas-fired furnace performance tests of epoxy primers for intumescent coatings

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Catala, Pere

    2014-01-01

    , either to ensure adhesion of the intumescent coating to the steel or to provide corrosion resistance. It is essential to document the performance of the intumescent coating together with the primer to ensure the overall quality of coating system. In the present work, two epoxy primers were used...... to a gas-fired furnace following the ISO834 fire curve (a so-called cellulosic fire), one of the primers selected performed well and the other poorly. From tests in the electrically heated oven, it was found that both primers were sensitive to the film thickness employed and the presence of oxygen....... At oxygen-rich conditions, higher primer thicknesses gave weaker performance. In addition, a color change from red to black was observed in nitrogen, while the color remained red in the oxygen-nitrogen mixture. In summary, the results suggest that an adequate choice of primer, primer thickness...

  8. Graphene/Epoxy Coating as Multifunctional Material for Aircraft Structures

    Directory of Open Access Journals (Sweden)

    Tullio Monetta

    2015-06-01

    Full Text Available Recently, the use of graphene as a conductive nanofiller in the preparation of inorganic/polymer nanocomposites has attracted increasing interest in the aerospace field. The reason for this is the possibility of overcoming problems strictly connected to the aircraft structures, such as electrical conductivity and thus lightning strike protection. In addition, graphene is an ideal candidate to enhance the anti-corrosion properties of the resin, since it absorbs most of the light and provides hydrophobicity for repelling water. An important aspect of these multifunctional materials is that all these improvements can be realized even at very low filler loadings in the polymer matrix. In this work, graphene nanoflakes were incorporated into a water-based epoxy resin, and then the hybrid coating was applied to Al 2024-T3 samples. The addition of graphene considerably improved some physical properties of the hybrid coating as demonstrated by Electrochemical Impedance Spectroscopy (EIS analysis, ameliorating anti-corrosion performances of raw material. DSC measurements and Cross-cut Test showed that graphene did not affect the curing process or the adhesion properties. Moreover, an increment of water contact angle was displayed.

  9. Chloride-induced corrosion mechanism and rate of enamel- and epoxy-coated deformed steel bars embedded in mortar

    International Nuclear Information System (INIS)

    Tang, Fujian; Chen, Genda; Brow, Richard K.

    2016-01-01

    The chloride-induced corrosion mechanisms of uncoated, pure enamel (PE)-coated, mixed enamel (ME)-coated, double enamel (DE)-coated, and fusion bonded epoxy (FBE)-coated deformed steel bars embedded in mortar cylinders are investigated in 3.5 wt.% NaCl solution and compared through electrochemical tests and visual inspection. Corrosion initiated after 29 or 61 days of tests in all uncoated and enamel-coated steel bars, and after 244 days of tests in some FBE-coated steel bars. In active stage, DE- and FBE-coated steel bars are subjected to the highest and lowest corrosion rates, respectively. The uncoated and ME-coated steel bars revealed relatively uniform corrosion while the PE-, DE-, and FBE-coated steel bars experienced pitting corrosion around damaged coating areas. Due to the combined effect of ion diffusion and capillary suction, wet–dry cyclic immersion caused more severe corrosion than continuous immersion. Both exposure conditions affected the corrosion rate more significantly than the water–cement ratio in mortar design.

  10. Investigation of the Degradation Mechanisms of Particulate Reinforced Epoxy Coatings and Zinc-Rich Coatings Under an Erosion and Corrosion Environment for Oil and Gas Industry Applications

    Science.gov (United States)

    Wang, Dailin

    During oil and gas production and transportation, the presence of an oil-sand slurry, together with the presence of CO2, H2S, oxygen, and seawater, create an erosive/abrasive and corrosive environment for the interior surfaces of undersea pipelines transporting oil and gas from offshore platforms. Erosion/wear and corrosion are often synergic processes leading to a much greater material loss of pipeline cross-section than that caused by each individual process alone. Both organic coatings and metallic sacrificial coatings have been widely employed to provide protection to the pipeline steels against corrosion through barrier protection and cathodic protection, and these protection mechanisms have been well studied. However, coating performance under the synergic processes of erosion/wear and corrosion have been much less researched and coating degradation mechanisms when erosion/wear and corrosion are both going on has not been well elucidated. In the work presented in this dissertation, steel panels coated with filler reinforced epoxy coatings and carbon nanotubes (CNTs) reinforced zinc-rich coatings have been evaluated under erosion/wear followed by an exposure to a corrosive environment. Electrochemical tests and material characterization methods have been applied to study the degradation mechanisms of the coatings during the tests and coating degradation mechanisms have been proposed. While organic coatings with a lower amount of filler particles provided better protection in a corrosive environment alone and in solid particle impingement erosion testing alone, organic coatings with a higher amount of filler particles showed better performance during wear testing alone. A higher amount of filler particles was also beneficial in providing protection against wear and corrosion environment, and erosion and corrosion environment. Coating thickness played a significant role in the barrier properties of the coatings under both erosion and corrosion tests. When the

  11. A new strategy for improvement of the corrosion resistance of a green cerium conversion coating through thermal treatment procedure before and after application of epoxy coating

    Energy Technology Data Exchange (ETDEWEB)

    Mahidashti, Z. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Shahrabi, T., E-mail: tshahrabi34@modares.ac.ir [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), P.O. 16765-654, Tehran (Iran, Islamic Republic of)

    2016-12-30

    Highlights: • The Ce conversion coating was post-heated at various conditions. • The corrosion resistance of post-heated Ce films was evaluated. • A crack free and denser Ce film were obtained after post-heating. • The corrosion resistance of Ce film noticeably increased. • Post-heated Ce film resulted better protection performance of epoxy coating. - Abstract: The effect of post-heating of CeCC on its surface morphology and chemistry has been studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and contact angle (CA) measurements. The corrosion protection performance of the coatings was investigated by electrochemical impedance spectroscopy (EIS). The effect of thermal treatment of CeCC on the corrosion protection performance of epoxy coating was investigated by EIS. Results showed that the heat treatment of Ce film noticeably improved its corrosion resistance and adhesion properties compared to that of untreated samples. The CeCC deposited on the steel substrate at room temperature had a highly cracked structure, while the amount of micro-cracks significantly reduced after post-heating procedure. Results obtained from EIS analysis confirmed the effect of post-heating of CeCC on its corrosion protection performance enhancement. The increase of post-heating temperature and time up to 140 °C and 3 h led to better results.

  12. The impact of nano-coating on surface charge accumulation of epoxy resin insulator: characteristic and mechanism

    Science.gov (United States)

    Qi, Bo; Gao, Chunjia; Lv, Yuzhen; Li, Chengrong; Tu, Youping; Xiong, Jun

    2018-06-01

    The flashover phenomenon of the insulator is the main cause for insulating failure of GIS/GIL, and one of the most critical impacting factors is the accumulation of surface charge. The common methods to restrain the surface charge accumulation are reviewed in this paper. Through the reasonable comparison and analysis of these methods, nano-coatings for the insulator were selected as a way to restrain the surface charge accumulation. Based on this, six nano-coated epoxy resin samples with different concentrations of P25-TiO2 nanoparticles were produced. A high precision 3D surface charge measurement system was developed in this paper with a spatial resolution of 4.0 mm2 and a charge resolution of 0.01 µC (m2 · mV)‑1. The experimental results for the epoxy resin sample showed that with the concentration of nanoparticles of the coating material increasing, the surface charge density tended to first decrease and then increase. In the sample coated with 0.5% concentration of nanoparticles, the suppression effect is the optimum, leading to a 63.8% reduction of charge density under DC voltage. The application test for actual nano-coated GIS/GIL basin insulator indicated that the maximum suppression degree for the charge density under DC voltage could reach 48.3%, while it could reach 22.2% for switching impulse voltage and 12.5% for AC context. The control mechanism of nano-coatings on charge accumulation was proposed based on the analysis for surface morphology features and traps characteristics; the shallow traps dominate in the migration of charges while the deep traps operate on the charge accumulation. With the concentration of nanoparticles in nano-coating material mounting up, the density of shallow traps continuously increases, while for deep traps, it first decreases and then increases. For the sample with 0.5% concentration of nanoparticles coated, the competition between shallow traps and deep traps comes to the most balanced state, producing the most

  13. Occupational contact dermatitis caused by 1,3-benzenedimethanamine, N-(2-phenylethyl) derivatives in hardeners for epoxy paints and coatings.

    Science.gov (United States)

    Pesonen, Maria; Kuuliala, Outi; Suomela, Sari; Aalto-Korte, Kristiina

    2016-12-01

    Amines in epoxy hardeners are significant causes of occupational allergic contact dermatitis among workers who use epoxy resin systems. To describe a novel group of contact allergens: N-(2-phenylethyl) derivatives of the reactive amine 1,3-benzenedimethanamine (1,3-BDMA). We describe the clinical examinations and exposure of 6 patients with occupational contact allergy to derivatives of 1,3-BDMA. Of the 6 patients, 4 were spray painters who used epoxy paints, 1 was a floor layer who handled a variety of epoxy coatings, and 1 was a worker in epoxy hardener manufacture. We were able to confirm exposure to epoxy hardeners that contained derivatives of 1,3-BDMA in 5 of the 6 sensitized patients. Despite the close structural resemblance between derivatives of 1,3-BDMA and m-xylylenediamine (MXDA), only 3 patients reacted positively to MXDA. Concomitant contact allergy to diglycidyl ether of bisphenol A resin was seen in 2 of the 6 patients. Because of the lack of a commercially available patch test substance, the diagnosis of contact allergy to derivatives of 1,3-BDMA requires patch testing with either the epoxy hardener product or a hardener ingredient that contains the derivatives of 1,3-BDMA. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Improving the interfacial and mechanical properties of short glass fiber/epoxy composites by coating the glass fibers with cellulose nanocrystals

    Science.gov (United States)

    A. Asadi; M. Miller; Robert Moon; K. Kalaitzidou

    2016-01-01

    In this study, the interfacial and mechanical properties of cellulose nanocrystals (CNC) coated glass fiber/epoxy composites were investigated as a function of the CNC content on the surface of glass fibers (GF). Chopped GF rovings were coated with CNC by immersing the GF in CNC (0–5 wt%) aqueous suspensions. Single fiber fragmentation (SFF) tests showed that the...

  15. Characterization of Hybrid Epoxy Nanocomposites

    Science.gov (United States)

    Simcha, Shelly; Dotan, Ana; Kenig, Samuel; Dodiuk, Hanna

    2012-01-01

    This study focused on the effect of Multi Wall Carbon Nanotubes (MWCNT) content and its surface treatment on thermo-mechanical properties of epoxy nanocomposites. MWCNTs were surface treated and incorporated into two epoxy systems. MWCNT's surface treatments were based on: (a) Titania coating obtained by sol-gel process and (b) a nonionic surfactant. Thermo-mechanical properties improvement was obtained following incorporation of treated MWCNT. It was noticed that small amounts of titania coated MWCNT (0.05 wt %) led to an increase in the glass transition temperature and stiffness. The best performance was achieved adding 0.3 wt % titania coated MWCNT where an increase of 10 °C in the glass transition temperature and 30% in storage modulus were obtained. PMID:28348313

  16. Silane coupling agent for attaching fusion-bonded epoxy to steel.

    Science.gov (United States)

    Tchoquessi Diodjo, Madeleine R; Belec, Lénaïk; Aragon, Emmanuel; Joliff, Yoann; Lanarde, Lise; Perrin, François-Xavier

    2013-07-24

    We describe the possibility of using γ-aminopropyltriethoxysilane (γ-APS) to increase the durability of epoxy powder coating/steel joints. The curing temperature of epoxy powder coatings is frequently above 200 °C, which is seen so far as a major limitation for the use of the heat-sensitive aminosilane coupling agent. Despite this limitation, we demonstrate that aminosilane is a competitive alternative to traditional chromate conversion to enhance the durability of epoxy powder coatings/steel joints. Fourier-transform reflection-absorption infrared spectroscopy (FT-RAIRS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) were used to identify the silane deposition conditions that influence the adhesion of epoxy powder coatings on steel. We show that AFM analysis provides highly sensitive measurements of mechanical property development and, as such, the degree of condensation of the silane. The joint durability in water at 60 °C was lower when the pH of the γ-APS solution was controlled at 4.6 using formic acid, rather than that at natural pH (10.6). At the curing temperature of 220 °C, oxidation of the carbon adjacent to the amine headgroup of γ-APS gives amide species by a pseudofirst-order kinetics. However, a few amino functionalities remain to react with oxirane groups of epoxy resin and, thus, strengthen the epoxy/silane interphase. The formation of ammonium formate in the acidic silane inhibits the reaction between silane and epoxy, which consequently decreases the epoxy/silane interphase cohesion. We find that the nanoroughness of silane deposits increases with the cure temperature which is beneficial to the wet stability of the epoxy/steel joints, due to increased mechanical interlocking.

  17. Wear Behavior of Woven Roving Aramid / Epoxy Composite under Different Conditions

    Directory of Open Access Journals (Sweden)

    Asad A. Khalid

    2012-09-01

    Full Text Available Wear behavior studies of aramid woven roving /epoxy composite has been conducted. Sliding the material against smooth steel counter face under dry and  lubricated with oil conditions has been investigated. Powder of Silicon carbide has been mixed with the epoxy resin and tested also. The powder was mixed in a volumetric fraction of 10% with the epoxy resin. Four Laminates of six layers were fabricated by hand lay up  method. A pin on disc apparatus has been fabricated to conduct the sliding wear tests on specimens of (4 mm   4 mm   12 mm in size have been cut from the four laminates. The effect of sliding condition including dry, lubricated, dry with additives and lubricated with additives have been studied. Wear rate tests have been conducted at different sliding speeds and loads. Results show that the wear characteristics are influenced by the operating conditions and the construction of the composite material used. It was also found that the wear of aramid /epoxy composite onto the steel counter face were significantly reduced by using lubricant and additives but still took place.Keywords: Wear, Composite materials, Woven roving aramid, Epoxy, Additives, Lubricant.

  18. The study of a Mg-rich epoxy primer for protection of AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lu Xiangyu [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: zuoy@mail.buct.edu.c [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zhao Xuhui; Tang Yuming; Feng Xingguo [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-01-15

    Research highlights: {yields} A Mg-rich epoxy primer was prepared by adding pure magnesium particles in epoxy coating. Cross scratch testing results showed that in 3% NaCl solution the Mg-rich primer showed better protection for AZ91D magnesium alloy than the same epoxy primer without Mg addition. {yields} The open circuit potential of AZ91D alloy in NaCl solution decreased after coated with Mg-rich coating, suggesting that cathodic protection effect of the Mg-rich coating on AZ91D alloy was present. {yields} EIS studies showed that during the immersion tests of AZ91D alloy with Mg-rich coating the magnesium particles in coating dissolved with the charge-transfer resistance R{sub ct} at the magnesium particle/coating interface decreased and the double-layer capacitance Q{sub dl} increased. While the coating resistance remained stable for a long time and corrosion of the AZ91D alloy substrate was obviously delayed. - Abstract: A Mg-rich epoxy primer was prepared by adding pure magnesium particles to an epoxy coating. The coating properties were studied with electrochemical impedance spectroscopy (EIS), scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The Mg-rich primer showed better protection for AZ91D magnesium alloy than the same epoxy primer without Mg addition. The open circuit potential measurements showed cathodic protection effect of the Mg-rich primer on AZ91D alloy. Cross scratch testing showed that the Mg-rich primer provided better protection for the substrate than original epoxy coating. The precipitation of Mg(OH){sub 2} in the coating also provided some degree of barrier protection.

  19. The study of a Mg-rich epoxy primer for protection of AZ91D magnesium alloy

    International Nuclear Information System (INIS)

    Lu Xiangyu; Zuo Yu; Zhao Xuhui; Tang Yuming; Feng Xingguo

    2011-01-01

    Research highlights: → A Mg-rich epoxy primer was prepared by adding pure magnesium particles in epoxy coating. Cross scratch testing results showed that in 3% NaCl solution the Mg-rich primer showed better protection for AZ91D magnesium alloy than the same epoxy primer without Mg addition. → The open circuit potential of AZ91D alloy in NaCl solution decreased after coated with Mg-rich coating, suggesting that cathodic protection effect of the Mg-rich coating on AZ91D alloy was present. → EIS studies showed that during the immersion tests of AZ91D alloy with Mg-rich coating the magnesium particles in coating dissolved with the charge-transfer resistance R ct at the magnesium particle/coating interface decreased and the double-layer capacitance Q dl increased. While the coating resistance remained stable for a long time and corrosion of the AZ91D alloy substrate was obviously delayed. - Abstract: A Mg-rich epoxy primer was prepared by adding pure magnesium particles to an epoxy coating. The coating properties were studied with electrochemical impedance spectroscopy (EIS), scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The Mg-rich primer showed better protection for AZ91D magnesium alloy than the same epoxy primer without Mg addition. The open circuit potential measurements showed cathodic protection effect of the Mg-rich primer on AZ91D alloy. Cross scratch testing showed that the Mg-rich primer provided better protection for the substrate than original epoxy coating. The precipitation of Mg(OH) 2 in the coating also provided some degree of barrier protection.

  20. SYNTHESIS AND CORROSION PROTECTION BEHAVIOR OF EPOXYTiO2-MICACEOUS IRON OXIDE NANO - COMPOSITE COATING ON St-37

    Directory of Open Access Journals (Sweden)

    M. R. Khorram

    2016-03-01

    Full Text Available The micro layers micaceous iron oxide and nano-TiO 2 were incorporated into the epoxy resin by mechanical mixing and sonication process. Optical micrographs showed that the number and diameter size of nanoparticle agglomerates were decreased by sonication. The structure and composition of the nanocomposite was determined using transmission electron microscopy which showed the presence of dispersed nano-TiO 2 in the polymer matrix. The anticorrosive properties of the synthesized nano-composites coating were investigated using salt spray, electrochemical impedance spectroscopy and polarization measurement. The EIS results showed that coating resistance increased by addition of micaceous iron oxide micro layers and nano-TiO 2 particles to the epoxy coatings. It was observed that higher corrosion protection of nanocomposite coatings obtained by the addition of 3 %wt micaceous iron oxide and 4%wt nano-TiO 2 into epoxy resin.

  1. Thermoviscoelastic shape memory behavior for epoxy-shape memory polymer

    International Nuclear Information System (INIS)

    Chen, Jianguo; Liu, Liwu; Liu, Yanju; Leng, Jinsong

    2014-01-01

    There are various applications for shape memory polymer (SMP) in the smart materials and structures field due to its large recoverable strain and controllable driving method. The mechanical shape memory deformation mechanism is so obscure that many samples and test schemes have to be tried in order to verify a final design proposal for a smart structure system. This paper proposes a simple and very useful method to unambiguously analyze the thermoviscoelastic shape memory behavior of SMP smart structures. First, experiments under different temperature and loading conditions are performed to characterize the large deformation and thermoviscoelastic behavior of epoxy-SMP. Then, a rheological constitutive model, which is composed of a revised standard linear solid (SLS) element and a thermal expansion element, is proposed for epoxy-SMP. The thermomechanical coupling effect and nonlinear viscous flowing rules are considered in the model. Then, the model is used to predict the measured rubbery and time-dependent response of the material, and different thermomechanical loading histories are adopted to verify the shape memory behavior of the model. The results of the calculation agree with experiments satisfactorily. The proposed shape memory model is practical for the design of SMP smart structures. (paper)

  2. Plasma Treated Multi-Walled Carbon Nanotubes (MWCNTs for Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Jie Lian

    2011-12-01

    Full Text Available Plasma nanocoating of allylamine were deposited on the surfaces of multi-walled carbon nanotubes (MWCNTs to provide desirable functionalities and thus to tailor the surface characteristics of MWCNTs for improved dispersion and interfacial adhesion in epoxy matrices. Plasma nanocoated MWCNTs were characterized using scanning electron microscopy (SEM, high-resolution transmission electron microscopy (HR-TEM, surface contact angle, and pH change measurements. Mechanical testing results showed that epoxy reinforced with 1.0 wt % plasma coated MWCNTs increased the tensile strength by 54% as compared with the pure epoxy control, while epoxy reinforced with untreated MWCNTs have lower tensile strength than the pure epoxy control. Optical and electron microscopic images show enhanced dispersion of plasma coated MWCNTs in epoxy compared to untreated MWCNTs. Plasma nanocoatings from allylamine on MWCNTs could significantly enhance their dispersion and interfacial adhesion in epoxy matrices. Simulation results based on the shear-lag model derived from micromechanics also confirmed that plasma nanocoating on MWCNTs significantly improved the epoxy/fillers interface bonding and as a result the increased composite strength.

  3. A new approach for enhancement of the corrosion protection properties and interfacial adhesion bonds between the epoxy coating and steel substrate through surface treatment by covalently modified amino functionalized graphene oxide film

    International Nuclear Information System (INIS)

    Parhizkar, N.; Shahrabi, T.; Ramezanzadeh, B.

    2017-01-01

    Highlights: •The steel substrate was treated by a covalently modified amino functionalized graphene oxide (fGO) film. •Deposition of fGO film at the interface of steel and epoxy could effectively improve the adhesion strength and corrosion protection properties. •More stable and stronger interfacial bonds was obtained when treating the interface by fGO film. -- Abstract: This study introduces a novel surface treatment approach of steel substrate by covalent modification of graphene oxide (fGO) nanosheets with 3-aminopropyltriethoxysilane to improve the adhesion and corrosion protection properties of an epoxy coating. The effect of fGO film on the epoxy coating performance was studied by field-emission scanning electron microscopy (FE-SEM), X-Ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), Pull-off adhesion, salt spray and cathodic delamination tests. Results revealed that deposition of fGO film on steel surface can effectively improve the adhesion strength and corrosion protection properties and reduce the cathodic delamination rate of the epoxy coating.

  4. Electrochemical investigation of the properties of Co doped ZnO nanoparticle as a corrosion inhibitive pigment for modifying corrosion resistance of the epoxy coating

    International Nuclear Information System (INIS)

    Rostami, M.; Rasouli, S.; Ramezanzadeh, B.; Askari, A.

    2014-01-01

    Highlights: • Corrosion inhibitive pigment based on ZnOCo was synthesized through combustion method. • Doping ZnO nanoparticle with Co enhanced its inhibition properties considerably. • ZnOCo nanoparticle could enhance corrosion protective performance of epoxy coating. • Co doped ZnO nanoparticles behaved as efficient barrier and inhibitive pigment. - Abstract: Co doped ZnO nanoparticles were synthesized by combustion method. Then, the epoxy nanocomposites were prepared using various amounts of nanoparticles. Salt spray and electrochemical impedance spectroscopy (EIS) were used in order to investigate the corrosion inhibition effects of nanoparticles on the steel substrate. The morphology and composition of the films precipitated on the steel surface were investigated by scanning electron microscope (SEM) and energy dispersive spectroscopy. Results revealed that the corrosion inhibition properties of ZnO nanoparticle were significantly enhanced after doping with Co. Moreover, Co doped ZnO nanoparticles enhanced the corrosion resistance of the epoxy coating effectively

  5. Anti-corrosion mechanism of epoxy-resin and different content Fe2O3 coatings on magnesium alloy

    Science.gov (United States)

    Jin, Tao; Kong, Fan-mei; Bai, Rui-qin; Zhang, Ru-liang

    2016-12-01

    In this study, anti-corrosion coatings were prepared and coated successfully on magnesium alloy substrates by mixing nanopowders, solvent, curing agent with epoxy resin. The effect of the amount of iron trioxide (Fe2O3) on the adhesion strength and corrosion resistance on magnesium alloy was investigated with standard protocols, and electrochemical measurements were also made in 3.5 wt.% NaCl solutions. The surface morphology and corrosion mechanism after corrosion tests was characterized using FESEM analysis. Nanoparticles in matrix acted as filler, and interstitial cross-linked spaces and other coating artifacts regions (micro cracks and voids) would all affect the anti-corrosion properties of coating. The results showed the proper powder content not only provided adhesion strength to these coatings but also improved obviously their anticorrosion. Hydrogen bound to the amine nitrogen (1N) could take part in the curing process rather than hydrogen of the amide site due to the smaller Δ G and the more stable configuration.

  6. High-Performance Epoxy-Resin-Bonded Magnets Produced from the Sm2Fe17Nx Powders Coated by Copper and Zinc Metals

    Science.gov (United States)

    Noguchi, Kenji; Machida, Ken-ichi; Adachi, Gin-ya

    2001-04-01

    Fine powders of Sm2Fe17Nx coated with copper metal reduced from CuCl2 and/or zinc metal subsequently derived by photo-decomposition of diethylzinc [Zn(C2H5)2] were prepared, and their magnetic properties were characterized in addition to those of epoxy-resin-bonded magnets produced from the coated powders (Cu/Sm2Fe17Nx, Zn/Sm2Fe17Nx and Zn/Cu/Sm2Fe17Nx). The remanence (Br) and maximum energy product [(\\mathit{BH})max] of double metal-coated Zn/Cu/Sm2Fe17Nx powders were maintained at higher levels than those of single Zn metal-coated Sm2Fe17Nx ones (Zn/Sm2Fe17Nx) even after heat treatment at 673 K since the oxidation resistance and thermal stability were effectively improved by formation of the thick and uniform protection layer on the surface of Sm2Fe17Nx particles. Moreover, the epoxy-resin-bonded magnets produced from the Zn/Cu/Sm2Fe17Nx powders possessed good corrosion resistance in air at 393 K which it resulted in the smaller thermal irreversible flux loss than that of uncoated and single Zn metal-coated Sm2Fe17Nx powders in the temperature range of above 393 K.

  7. Comparison of the degradation behaviour of fusion-bonded epoxy powder coating systems under flowing and static immersion

    International Nuclear Information System (INIS)

    Wei, Y.H.; Zhang, L.X.; Ke, W.

    2006-01-01

    The degradation of three different fusion-bonded epoxy (FBE) powder coating systems under flowing and static immersion condition has been monitored using electrochemical impedance spectroscopy (EIS) when exposed to 3% NaCl aqueous solution at 60 o C. The aim of this project was to determine the impact of flowing condition on the degradation of the protective properties of polymer coatings during exposure to corrosive medium. Using a rotating cylinder apparatus, the immersion tests under the flowing condition were performed. The relative permittivity of coating, ε r =C c δε 0 A, where the coating capacitance C c was calculated from the high frequency data of impedance spectrum, was selected as the index to monitor property variation with immersion time. Experimental results showed that the flowing condition aggravated the deterioration of coatings. The results were interpreted in terms of a model in which flowing condition changes coating/solution interface state and then accelerates the ions to diffuse through the coating. The electrochemical results were in agreement with the final visual observation. The present investigation suggests that flowing test provides an effective accelerating way to evaluate the degradation of coating system

  8. Processing, properties and applications of composites using powder-coated epoxy towpreg technology

    Science.gov (United States)

    Bayha, T. D.; Osborne, P. P.; Thrasher, T. P.; Hartness, J. T.; Johnston, N. J.; Marchello, J. M.; Hugh, M. K.

    1993-01-01

    Composite manufacturing using the current prepregging technology of impregnating liquid resin into three-dimensionally reinforced textile preforms can be a costly and difficult operation. Alternatively, using polymer in the solid form, grinding it into a powder, and then depositing it onto a carbon fiber tow prior to making a textile preform is a viable method for the production of complex textile shapes. The powder-coated towpreg yarn is stable, needs no refrigeration, contains no solvents and is easy to process into various woven and braided preforms for later consolidation into composite structures. NASA's Advanced Composites Technology (ACT) program has provided an avenue for developing the technology by which advanced resins and their powder-coated preforms may be used in aircraft structures. Two-dimensional braiding and weaving studies using powder-coated towpreg have been conducted to determine the effect of resin content, towpreg size and twist on textile composite properties. Studies have been made to customize the towpreg to reduce friction and bulk factor. Processing parameters have been determined for three epoxy resin systems on eight-harness satin fabric, and on more advanced 3-D preform architectures for the downselected resin system. Processing effects and the resultant mechanical properties of these textile composites will be presented and compared.

  9. Synthesize and characterization of a novel anticorrosive cobalt ferrite nanoparticles dispersed in silica matrix (CoFe2O4-SiO2) to improve the corrosion protection performance of epoxy coating

    International Nuclear Information System (INIS)

    Gharagozlou, M.; Ramezanzadeh, B.; Baradaran, Z.

    2016-01-01

    Highlights: • An anticorrosive cobalt ferrite nanopigment dispersed in silica matrix was synthesized. • The nanopigment showed proper inhibition performance in solution study. • The nanopigment significantly improved the corrosion resistance of the epoxy coating. - Abstract: This study aimed at studying the effect of an anticorrosive nickel ferrite nanoparticle dispersed in silica matrix (NiFe 2 O 4 -SiO 2 ) on the corrosion protection properties of steel substrate. NiFe 2 O 4 and NiFe 2 O 4 -SiO 2 nanopigments were synthesized and then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). Then, 1 wt.% of nanopigments was dispersed in an epoxy coating and the resultant nanocomposites were applied on the steel substrates. The corrosion inhibition effects of nanopigments were tested by an electrochemical impedance spectroscopy (EIS) and salt spray test. Results revealed that dispersing nickel ferrite nanoparticles in a silica matrix (NiFe 2 O 4 -SiO 2 ) resulted in the enhancement of the nanopigment dispersion in the epoxy coating matrix. Inclusion of 1 wt.% of NiFe 2 O 4 -SiO 2 nanopigment into the epoxy coating enhanced its corrosion protection properties before and after scratching.

  10. The control mechanism of surface traps on surface charge behavior in alumina-filled epoxy composites

    International Nuclear Information System (INIS)

    Li, Chuanyang; Hu, Jun; Lin, Chuanjie; He, Jinliang

    2016-01-01

    To investigate the role surface traps play in the charge injection and transfer behavior of alumina-filled epoxy composites, surface traps with different trap levels are introduced by different surface modification methods which include dielectric barrier discharges plasma, direct fluorination, and Cr 2 O 3 coating. The resulting surface physicochemical characteristics of experimental samples were observed using atomic force microscopy, scanning electron microscopy and fourier transform infrared spectroscopy. The surface potential under dc voltage was detected and the trap level distribution was measured. The results suggest that the surface morphology of the experimental samples differs dramatically after treatment with different surface modification methods. Different surface trap distributions directly determine the charge injection and transfer property along the surface. Shallow traps with trap level of 1.03–1.11 eV and 1.06–1.13 eV introduced by plasma and fluorination modifications are conducive for charge transport along the insulating surface, and the surface potential can be modified, producing a smoother potential curve. The Cr 2 O 3 coating can introduce a large number of deep traps with energy levels ranging from 1.09 to 1.15 eV. These can prevent charge injection through the reversed electric field formed by intensive trapped charges in the Cr 2 O 3 coatings. (paper)

  11. Stronger Fire-Resistant Epoxies

    Science.gov (United States)

    Fohlen, George M.; Parker, John A.; Kumar, Devendra

    1988-01-01

    New curing agent improves mechanical properties and works at lower temperature. Use of aminophenoxycyclotriphosphazene curing agents yields stronger, more heat- and fire-resistant epoxy resins. Used with solvent if necessary for coating fabrics or casting films.

  12. Off-Axis Ratcheting Behavior of Unidirectional Carbon/Epoxy Laminate under Asymmetric Cyclic Loading at High Temperature

    Science.gov (United States)

    2011-11-01

    ply unidirectional carbon/epoxy laminates [0]12 were fabricated from the prepreg tape of P3252-20 (TORAY). They were laid up by hand and cured in...Off-Axis Ratcheting Behavior of Unidirectional Carbon/Epoxy Laminate under Asymmetric Cyclic Loading at High Temperature Takafumi Suzuki 1 and...Development of an engineering model for predicting the off-axis ratcheting behavior of a unidirectional CFRP laminate has been attempted. For this purpose

  13. The mechanism of cathodic electrodeposition of epoxy coatings and the corrosion behaviour of the electrodeposited

    Directory of Open Access Journals (Sweden)

    VESNA B. MISKOVIC-STANKOVIC

    2002-05-01

    Full Text Available The model of organic film growth on a cathode during electrodeposition process proposes the current density-time and film thickness-time relationships and enables the evaluation of the rate contants for the electrochemical reaction of OH– ion evolution and for the chemical reaction of organic film deposition. The dependences of film thickness and rate constants on the applied voltage, bath temperature and resin concentration in the electrodeposition bath have also been obtained. The deposition parameters have a great effect on the cathodic electrodeposition process and on the protective properties of the obtained electrodeposited coatings. From the time dependences of the pore resistance, coating capacitance and relative permittivity, obtained from impedance measurements, the effect of applied voltage, bath temperature and resin concentration on the protective properties of electrodeposited coatings has been shown. Using electrochemical impedance spectroscopy, thermogravimetric analysis, gravimetric liquid sorption experiments, differential scanning calorimetry and optical miscroscopy, the corrosion stability of epoxy coatings was investigated. A mechanism for the penetration of electrolyte through an organic coating has been suggested and the shape and dimensions of the conducting macropores have been determined. It was shown that conduction through a coating depends only on the conduction through the macropores, although the quantity of electrolyte in the micropores of the polymer net is about one order of magnitude greater than that inside the conducting macropores.

  14. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    Science.gov (United States)

    Jalili, M.; Rostami, M.; Ramezanzadeh, B.

    2015-02-01

    Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

  15. Study of the fire resistant behavior of unfilled and carbon nanofibers reinforced polybenzimidazole coating for structural applications

    OpenAIRE

    Iqbal, H.M.S.; Stec, A.A.; Patel, P.; Bhowmik, S.; Benedictus, R.

    2013-01-01

    With increasing interest in epoxy-based carbon fiber composites for structural applications, it is important to improve the fire resistant properties of these materials. The fire resistant performance of these materials can be improved either by using high performance epoxy resin for manufacturing carbon fiber composite or by protecting the previously used epoxy-based composite with some fire resistant coating. In this context, work is carried out to evaluate the fire resistance performance o...

  16. Effects of Surface Treatments of Montmorillonite Nanoclay on Cure Behavior of Diglycidyl Ether of Bisphenol A Epoxy Resin

    International Nuclear Information System (INIS)

    Tcherbi-Narteh, A.; Hosur, M.V.; Triggs, E.; Jelaani, S.

    2013-01-01

    Diglycidyl ether of Bisphenol A (DGEBA) based SC-15 epoxy resin was modified with three different commercially available montmorillonite (MMT) nanoclay: Nanomer I.28E and Cloisite 10A and 30B. Cure behavior of nanocomposites was studied using a variety of techniques. Primary focus of this study was to investigate influence of different surface modifications of MMT nanoclay on rheological properties and cure behavior of SC-15 epoxy resin. By adding MMT to SC-15 epoxy resin, chemistry of the epoxy is altered leading to changes in rheological properties and ultimately enthalpy and activation energy of reactions. Addition of Nanomer I.28E delayed gelation, while Cloisite 10A and 30B accelerated gelation, regardless of the curing temperature. Activation energy of reaction was lower with the addition of Nanomer I.28E and Cloisite 10A and higher for Cloisite 30B compared to neat SC-15 epoxy composite.

  17. Active corrosion protection performance of an epoxy coating applied on the mild steel modified with an eco-friendly sol-gel film impregnated with green corrosion inhibitor loaded nanocontainers

    Science.gov (United States)

    Izadi, M.; Shahrabi, T.; Ramezanzadeh, B.

    2018-05-01

    In this study the corrosion resistance, active protection, and cathodic disbonding performance of an epoxy coating were improved through surface modification of steel by a hybrid sol-gel system filled with green corrosion inhibitors loaded nanocontainer as intermediate layer on mild steel substrate. The green inhibitor loaded nanocontainers (GIN) were used to induce active inhibition performance in the protective coating system. The corrosion protection performance of the coated panels was investigated by electrochemical impedance spectroscopy (EIS), salt spray, and cathodic disbonding tests. It was observed that the corrosion inhibition performance of the coated mild steel panels was significantly improved by utilization of active multilayer coating system. The inhibitor release from nanocontainers at the epoxy-silane film/steel interface resulted in the anodic and cathodic reactions restriction, leading to the lower coating delamination from the substrate and corrosion products progress. Also, the active inhibition performance of the coating system was approved by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive X-ray (EDS) analysis on the panels with artificial defects. The inhibitive agents were released to the scratch region and blocked the active sites on the metal surface.

  18. Adhesion enhancement of Al coatings on carbon/epoxy composite surfaces by atmospheric plasma

    International Nuclear Information System (INIS)

    Coulon, J.F.; Tournerie, N.; Maillard, H.

    2013-01-01

    Adhesion strengths between aluminium thin film coatings and manufactured carbon/epoxy composite surfaces were measured by assessing fracture tensile strengths using pull-off tests. The effect of the substrate roughness (nm to μm) of these composite surfaces on adhesion was studied by examining the surface free energies and adhesion strengths. The adhesion strengths of the coatings varied significantly. To improve the coating adhesion, each composite surface was treated with atmospheric plasma prior to deposition, which resulted in an increase in the surface free energy from approximately 40 mJ/m 2 to 70 mJ/m 2 because the plasma pretreatment led to the formation of hydrophilic C-O and C=O bonds on the composite surfaces, as demonstrated by X-ray photoelectron spectroscopy analyses. The adhesion strengths of the coatings were enhanced for all surface roughnesses studied. In our study, the effect of mechanical adhesion due to roughness was separated from the effect of modifying the chemical bonds with plasma activation. The adhesion ability of the pure resin was relatively weak. Increasing the surface roughness largely improved the adhesion of the resin surface. Plasma treatment of the pure resin also increased the surface adhesion. Our study shows that plasma activation effectively enhances the adhesion of manufactured composites, even when the surface roughness is on the order of microns. The ageing of the surface activation was also investigated, and the results demonstrate that atmospheric plasma has potential for use in the pretreatment of composite materials.

  19. Experimental Investigation on Fatigue Behavior of Epoxy Resin under Load and Displacement Controls

    Directory of Open Access Journals (Sweden)

    Mahmood Mehrdad Shokrieh

    2014-12-01

    Full Text Available The mechanical properties of epoxy resin including tensile and flexural modulus, tensile and flexural strength for static conditions are currently studied. The frequency effect as significant parameter at room temperature is investigated and fatigue behavior of the epoxy resin in tension-tension loading conditions for different frequencies of 2, 3 and 5 Hz are obtained. The epoxy resin has been taken under flexural bending fatigue loading and fatigue life is investigated. The results of the experiments show the values of 2.5 and 3 GPa of tensile and flexural modules and 59.98 and 110.02 MPa of tensile and flexural strengths for the resin, respectively. To achieve a linear load-deflection relationship in a three-point bending experiment, a maximum allowable deflection of 5 mm is acquired. The relationship between the frequency and fatigue life shows higher frequency results in lower fatigue life. Loading with frequency of 2 Hz has provided 5.8 times more fatigue life compared with 5 Hz loading. For a tension-tension fatigue loading condition, the variation of tensile module of epoxy resin shows no noticeable change during the fatigue loading condition. This module decreases significantly only in the primary and failure cycles close to the fracture point. In further experiments, fatigue behavior of epoxy resin was tested under flexural bending fatigue loadings with controlled deflection at room temperature. Maximum applied normalized stresses versus the number of cycles to failure curve are illustrated and it can be performed in order to predict the number of cycles to failure for the resin in arbitrary applied normal stresses as well.

  20. Investigation of non-isocyanate urethane functional latexes and carbon nanofiller/epoxy coatings

    Science.gov (United States)

    Meng, Lei

    This dissertation consists of two parts. In the first part, a new class of non-isocyanate urethane methacrylates was synthesized and the effect of the new monomers on the urethane functional latex was investigated. The second part focused on a comparison of carbon nanofillers in inorganic/organic epoxy coating system for anticorrosive applications. A new class of non-isocyanate urethane methacrylates (UMAs) monomers was synthesized through an environmentally friendly non-isocyanate pathway. The kinetics of seeded semibatch emulsion polymerization of UMAs with methyl methacrylate (MMA) and butyl acrylate (BA) was monitored. The particle size and morphology were investigated by dynamic light scattering (DLS), ultrasound acoustic attenuation spectroscopy (UAAS) and transmission electron microscopy (TEM). The minimum film formation temperature (MFFT), mechanical and viscoelastic properties were studied. It was found that the emulsion polymerization processes all proceeded via Smith-Ewart control, leading to the uniform morphology and particle size. The glass transition temperature (Tg) and the mechanical properties of poly(MMA/BA/UMA) decreased with the increasing chain length of urethane methacrylate monomers due to the increasing flexibility of side chains. Without the effect of Tg, lower MFFT and improved mechanical properties were observed from urethane functional latexes. The improved mechanical properties were due to the increasing particle interaction by forming hydrogen bonding. Furthermore, the effect of urethane functionality in terms of the polymer composition, the location and the concentration was investigated by the batch, single-stage and two-stage semibatch polymerization of 2-[(butylcarbamoyl)oxy]ethyl methacrylate (BEM) with MMA and BA. The core-shell and homogeneous structures were evaluated by TEM, differential scanning calorimetry (DSC), and solid state nuclear magnetic resonance (SS-NMR). The compositional drift was observed from the batch

  1. The Role of interfacial layers on the performance of an epoxy / polyester powder coated Aluminium Alloy

    International Nuclear Information System (INIS)

    Mirabedini, M.; Moradian, S.; Scanteburg, D.; Thonpson, G.E.

    2002-01-01

    The influence of polyacrylic acid and a blend of polyacrylic acid with hexa fluorozirconic acid treatments on the performance of an epoxy/polyester powder coating on a 1050 Al substrate has been studied and compared to the performance of the same system using a so-called chromate/phosphate conversion coating. The chemical interactions between pretreatments and Al substrates were examined using FTIR spectroscopy and various accelerated test methods were also employed. Two mechanical adhesion measurement methods were used under wet and dry conditions, namely a vertical pull-off test in the dry state and the tape test under dry conditions. The water permeation of the differently pretreated powder coated samples was studied using a capacitance measurement method. FTIR results showed two modes of interaction; namely ionic and complex formation between COO - and Al 3+ Various experiments revealed that polyacrylic acid improved only the dry adhesion but as a standing alone treatment it did not provide an overall improvement in anti-corrosive performance. The water uptake measurements proved that pretreatment does not considerably affect the properties of the coatings during water permeation stage. The use of various techniques revealed that relatively good performance of powder coating is due to a high ohmic resistance of the coating prior to and after saturation with water, reasonably low water solubility and good adhesion to the substrate

  2. Effect of Surface Contaminants Remained on the Blasted Surface on Epoxy Coating Performance and Corrosion Resistance

    International Nuclear Information System (INIS)

    Baek, Kwang Ki; Park, Chung Seo; Kim, Ki Hong; Chung, Mong Kyu; Park, Jin Hwan

    2006-01-01

    One of the critical issues in the coating specification is the allowable limit of surface contaminant(s) - such as soluble salt(s), grit dust, and rust - after grit blasting. Yet, there is no universally accepted data supporting the relationship between the long-term coating performance and the amount of various surface contaminants allowed after grit blasting. In this study, it was attempted to prepare epoxy coatings applied on grit-blasted steel substrate dosed with controlled amount of surface contaminants - such as soluble salt(s), grit dust, and rust. Then, coating samples were subjected to 4,200 hours of cyclic test(NORSOK M-501), which were then evaluated in terms of resistance to rust creepage, blistering, chalking, rusting, cracking and adhesion strength. Additional investigations on the possible damage at the paint/steel interface were carried out using an Electrochemical Impedance Spectroscopy(EIS) and observations of under-film-corrosion. Test results suggested that the current industrial specifications were well matched with the allowable degree of rust, whereas the allowable amount of soluble salt and grit dust after grit blasting showed a certain deviation from the specifications currently employed for fabrication of marine vessels and offshore facilities

  3. Radiochemical ageing of epoxy coating for nuclear plants

    International Nuclear Information System (INIS)

    Queiroz, D.P.R.; Fraisse, F.; Fayolle, B.; Kuntz, M.; Verdu, J.

    2010-01-01

    The degradation of an epoxy-amine network exposed to gamma irradiation in oxygen atmosphere has been studied by using a variety of analytical methods, including infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and sol-gel analysis. Results show that the oxidation of epoxy systems grows with the irradiation dose. Hydroperoxides, which are species resulting from oxidation, were identified and quantified by DSC. As indicated by the sol-gel analysis, the mechanism of degradation of chain scission seems to be predominant over crosslinking. The modifications induced by irradiation reflect in a greater capacity of water absorption.

  4. Surface modification of carbon/epoxy prepreg using oxygen plasma and its effect on the delamination resistance behavior of carbon/epoxy composites

    International Nuclear Information System (INIS)

    Kim, M.H.; Rhee, K.Y.; Kim, H.J.; Jung, D.H.

    2007-01-01

    It was shown in previous study that the fracture toughness of carbon/epoxy laminated composites could be significantly improved by modifying the surface of the prepreg using Ar + irradiation in an oxygen environment. In this study, the surface of carbon/epoxy prepreg was modified using an oxygen plasma to improve the delamination resistance behavior of carbon/epoxy laminated composites. The variation of the contact angle on the prepreg surface was determined as a function of the modification time, in order to determine the optimal modification time. An XPS analysis was conducted to investigate the chemical changes on the surface of the prepreg caused by the plasma modification. Mode I delamination resistance curves of the composites with and without surface modification were plotted as a function of the delamination increment. The results showed that the contact angle varied from ∼64 o to ∼47 o depending on the modification time and reached a minimum for a modification time of 30 min. The XPS analysis showed that the hydrophilic carbonyl C=O group was formed by the oxygen plasma modification. The results also showed that the delamination resistance behavior was significantly improved by the plasma modification of the prepreg. This improvement was caused by the better layer-to-layer adhesion as well as increased interfacial strength between the fibers and matrix

  5. Transient thermal-mechanical behavior of cracked glass-cloth-reinforced epoxy laminates at low temperatures

    International Nuclear Information System (INIS)

    Shindo, Y.; Ueda, S.

    1997-01-01

    We consider the transient thermal-mechanical response of cracked G-10CR glass-cloth-reinforced epoxy laminates with temperature-dependent properties. The glass-cloth-reinforced epoxy laminates are suddenly cooled on the surfaces. A generalized plane strain finite element model is used to study the influence of warp angle and crack formation on the thermal shock behavior of two-layer woven laminates at low temperatures. Numerical calculations are carried out, and the transient temperature distribution and the thermal-mechanical stresses are shown graphically

  6. Fire performance, microstructure and thermal degradation of an epoxy based nano intumescent fire retardant coating for structural applications

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Hammad, E-mail: engr.hammad.aziz03@gmail.com; Ahmad, Faiz, E-mail: faizahmad@petronas.com.my; Yusoff, P. S. M. Megat; Zia-ul-Mustafa, M. [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh 31750, Perak (Malaysia)

    2015-07-22

    Intumescent fire retardant coating (IFRC) is a passive fire protection system which swells upon heating to form expanded multi-cellular char layer that protects the substrate from fire. In this research work, IFRC’s were developed using different flame retardants such as ammonium polyphosphate, expandable graphite, melamine and boric acid. These flame retardants were bound together with the help of epoxy binder and cured together using curing agent. IFRC was then reinforced with nano magnesium oxide and nano alumina as inorganic fillers to study their effect towards fire performance, microstructure and thermal degradation. Small scale fire test was conducted to investigate the thermal insulation of coating whereas fire performance was calculated using thermal margin value. Field emission scanning electron microscopy was used to examine the microstructure of char obtained after fire test. Thermogravimetric analysis was conducted to investigate the residual weight of coating. Results showed that the performance of the coating was enhanced by reinforcement with nano size fillers as compared to non-filler based coating. Comparing both nano size magnesium oxide and nano size alumina; nano size alumina gave better fire performance with improved microstructure of char and high residual weight.

  7. Influence of a microcomposite and a nanocomposite on the properties of an epoxy-based powder coating

    International Nuclear Information System (INIS)

    Piazza, Diego; Lorandi, Natalia P.; Pasqual, Charles I.; Scienza, Lisete C.; Zattera, Ademir J.

    2011-01-01

    Highlights: → New materials for using as protective coatings for metal surfaces. → Development of nanostructured powder paints. → Characterization of the new material in the powder and coating form. → Development of a new material for use in the automotive industry, industrial production of appliances, furniture industry. → Development of new material using the process of mixing using a twin-screw extruder, followed by sintering process on a metal plate. - Abstract: The incorporation of nanoclays into coatings has been considered to be commercially favorable due to the improvements obtained in the barrier, thermal, and anticorrosion properties, among others, leading to the development of a new segment in the area of clean technologies: the application of nanocomposites to powder coatings. In this study, in order to compare the performance of a powder coating with the addition of a conventional load (barium sulfate) and a montmorillonite clay (MMT), two mixtures of commercial epoxy-based powder coating were prepared in the melt state, with the addition of 2 and 4% (w/w) of MMT, or 2 and 4% (w/w) of barium sulfate (BaSO 4 ). The thermal properties were investigated through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to evaluate the load dispersion and the morphology of the systems formed. The physical and anticorrosion properties of the coatings were also investigated. The interaction of the MMT with the polymeric matrix, associated to the aspect ratio, resulted in better barrier properties, thermal stability, and adhesion to the metal substrate.

  8. Characterization of the flexural behavior of a reactive graphitic nanofibers reinforced epoxy using a non-linear damage model

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Soumen [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States); Zhong Weihong [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States)]. E-mail: Katie.zhong@ndsu.edu; Gan, Yong X. [Department of Mechanical Engineering, Albert Nerken School of Engineering, Cooper Union for the Advancement of Science and Art, 51 Astor Place, New York City, NY 10003 (United States)

    2007-02-15

    In our previous work, a nano-epoxy was developed based on the preparation of reactive graphitic nanofibers (r-GNFs). The objective of this work is to study the effect of the r-GNFs in an epoxy resin on the mechanical properties of the resulting nano-epoxy composites. Three-point bending tests were carried out for the pure epoxy and nano-epoxy materials with 0.15, 0.2, 0.3, 0.5 wt% r-GNFs to obtain the flexural behaviors. The nano-epoxy composite containing 0.3 wt% of r-GNFs showed the best flexural properties including highest flexural strength, modules and ductility values among all the tested materials. Non-linear fracture mechanics (NLFM) was applied to analyze the phenomena occurred during the bending tests. A non-linear damage model was used to interpret the flexural stress-strain relationships of the tested materials, which showed agreement with the testing results. The fracture surfaces of the nano-epoxy composites were examined with scanning electron microscopy (SEM), and the morphological features on the SEM images also reveals that the nano-epoxy composites are tougher than the pure epoxy resin.

  9. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Jalili, M. [Nanomaterials and Nanocoatings Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Surface Coatings and Corrosion Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Rostami, M. [Nanomaterials and Nanocoatings Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Surface Coatings and Corrosion Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of)

    2015-02-15

    Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

  10. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    International Nuclear Information System (INIS)

    Jalili, M.; Rostami, M.; Ramezanzadeh, B.

    2015-01-01

    Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties

  11. Effects of Different Montmorillonite Nanoclay Loading on Cure Behavior and Properties of Diglycidyl Ether of Bisphenol A Epoxy

    Directory of Open Access Journals (Sweden)

    Alfred Tcherbi-Narteh

    2016-01-01

    Full Text Available The primary focus of this study was to understand the effects of different amounts of montmorillonite nanoclay (MMT loading on viscosity, cure behavior, reaction mechanism, and properties of diglycidyl ether of bisphenol A (DGEBA epoxy composites. Influence of 1–3 wt.% MMT on rheological and subsequent cure behavior of SC-15 epoxy resin was studied using nonisothermal and isothermal rheometry and differential scanning calorimetry (DSC. Rheological properties were influenced by different amounts of MMT at lower shear rates prior to and during curing. Cure reaction mechanism was unaffected by different MMT concentration; however heat and activation energy of reactions increased with increasing MMT loading. Samples with 2 wt.% MMT showed highest reaction rate constant, indicative of catalytic behavior. X-ray diffraction (XRD and transmission electron microscope (TEM revealed mainly intercalated microstructure throughout the MMT infused epoxy composite samples irrespective of the percent loading.

  12. Treatment of high-latency microcapsules containing an aluminium complex with an epoxy-functionalised trialkoxysilane.

    Science.gov (United States)

    Kamiya, Kazunobu; Suzuki, Noboru

    2016-12-01

    Some aluminium complexes are excellent catalysts of cationic polymerisation and are used for low-temperature and fast-curing adhesive, used in electronic part mounting. Microencapsulation is a suitable technique for getting high latency of the catalysts and long shelf life of the adhesives. For the higher latency in a cycloaliphatic epoxy compound, the microcapsule surface which retained small amount of aluminium complex was coated with epoxy polymer and the effect was examined. From the X-ray photoelectron spectroscopic results, the surface was recognised to be sufficiently coated and the differential scanning calorimetric analyses showed that the coating did not significantly affect the low-temperature and fast-curing properties of adhesive. After storing the mixture of cycloaliphatic epoxy compound, coated microcapsules, triphenylsilanol and silane coupling agent for 48 h at room temperature, the increase in viscosity was only 0.01 Pa s, resulting in the excellent shelf life.

  13. Enhancing the Heat Transfer Efficiency in Graphene-Epoxy Nanocomposites Using a Magnesium Oxide-Graphene Hybrid Structure.

    Science.gov (United States)

    Du, Fei-Peng; Yang, Wen; Zhang, Fang; Tang, Chak-Yin; Liu, Sheng-Peng; Yin, Le; Law, Wing-Cheung

    2015-07-08

    Composite materials, such as organic matrices doped with inorganic fillers, can generate new properties that exhibit multiple functionalities. In this paper, an epoxy-based nanocomposite that has a high thermal conductivity and a low electrical conductivity, which are required for the use of a material as electronic packaging and insulation, was prepared. The performance of the epoxy was improved by incorporating a magnesium oxide-coated graphene (MgO@GR) nanomaterial into the epoxy matrix. We found that the addition of a MgO coating not only improved the dispersion of the graphene in the matrix and the interfacial bonding between the graphene and epoxy but also enhanced the thermal conductivity of the epoxy while preserving the electrical insulation. By adding 7 wt % MgO@GR, the thermal conductivity of the epoxy nanocomposites was enhanced by 76% compared with that of the neat epoxy, and the electrical resistivity was maintained at 8.66 × 10(14) Ω m.

  14. Coating degradation at tank bottomdue to settled water

    International Nuclear Information System (INIS)

    Majeed, U.; Rizvi, M.A.; Khan, I.H.

    2008-01-01

    In the present work, coating degradation as a result of settled water on fuel storage tank bottoms has been reported with the help of electrochemical impedance spectroscopy (EIS), blister analysis and gravimetric analysis (water uptake). Blistering occurs underneath the coating at the tank bottom due to direct contact with settled water. Degradation behavior of polyamide epoxy coatings on mild steel has been reported in term of coating resistance at the start of the experiments, after 96 hours and at the end of EIS experiments. Coating degradation in terms of shift in phase angle (theta) at high frequency as a function of exposure time has also been reported. The blister formation and gravimetric analysis data has also been reported in support of EIS result. (author)

  15. Multi function Finishing and Pigment Printing of UV Cured Cotton/Polyester Fabrics Coated with Plasticized Epoxy Resin/ZnO Formulation

    International Nuclear Information System (INIS)

    Hassan, M.S.; Mousaa, I.M.; Ali, N.M.

    2015-01-01

    Cotton/ Polyester fabrics were coated with epoxy acrylate (EA) formulations plasticized by castor oil (CO), in the presence of benzophenone as initiator, ZnO (antibacterial agent) and pigment printing. Ultra violet (UV) irradiation was used as a curing system. The effect of UV irradiation time and CO percentage on the mechanical and crease recovery properties were investigated. The effect of the coating process on the cross-section feature by using scanning electron microscope (SEM), the antibacterial properties, water retardance, colour difference and the durability for washing of the coated fabrics were also investigated. From the results, it was found that the crease recovery and antibacterial properties were enhanced. Also, the colour durability against multiple washing cycles gave adequate results after application of the investigated coating formulation. The most fitting castor oil per cent was found to be 45%, while the 3% ZnO recorded the best antibacterial and mechanical properties. The pigment per cent that gave the highest durability and adequate colour strength was 0.6%.

  16. Effects of graphene oxides on the cure behaviors of a tetrafunctional epoxy resin

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available The influence of graphene oxides (GOs on the cure behavior and thermal stability of a tetrafunctional tetraglycidyl-4,4’-diaminodiphenylmethane cured with 4,4’-diaminodiphenylsulfone was investigated by using dynamic differential scanning calorimetry (DSC and thermogravimetric analysis (TGA. The dynamic DSC results showed that the initial reaction temperature and exothermal peak temperature decreased with the increase of GO contents. Furthermore, the addition of GO increased the enthalpy of epoxy cure reaction. Results from activation energy method showed that activation energies of GO/epoxy nanocomposites greatly decreased with the GO content in the latter stage, indicating that GOs significantly hindered the occurrence of vitrification. The oxygen functionalities, such as hydroxyl and carboxyl groups, on the surface of GOs acted as catalysts and facilitated the curing reaction and the catalytic effect increased with the GO contents. TGA results revealed that the addition of GOs decreased the thermal stability of epoxy.

  17. Influence of a microcomposite and a nanocomposite on the properties of an epoxy-based powder coating

    Energy Technology Data Exchange (ETDEWEB)

    Piazza, Diego [Polymers Laboratory, Caxias do Sul University - Exact Science and Technology Center, Francisco Getulio Vargas Street, 1130, Petropolis, CEP 95070-560 Caxias do Sul, RS (Brazil); Lorandi, Natalia P. [Corrosion and Surface Protection Laboratory, Caxias do Sul University - Exact Science and Technology Center, Francisco Getulio Vargas Street, 1130, Petropolis, CEP 95070-560 Caxias do Sul, RS (Brazil); Pasqual, Charles I. [Polymers Laboratory, Caxias do Sul University - Exact Science and Technology Center, Francisco Getulio Vargas Street, 1130, Petropolis, CEP 95070-560 Caxias do Sul, RS (Brazil); Scienza, Lisete C. [Corrosion and Surface Protection Laboratory, Caxias do Sul University - Exact Science and Technology Center, Francisco Getulio Vargas Street, 1130, Petropolis, CEP 95070-560 Caxias do Sul, RS (Brazil); Zattera, Ademir J., E-mail: ajzattera@terra.com.br [Polymers Laboratory, Caxias do Sul University - Exact Science and Technology Center, Francisco Getulio Vargas Street, 1130, Petropolis, CEP 95070-560 Caxias do Sul, RS (Brazil)

    2011-08-25

    Highlights: {yields} New materials for using as protective coatings for metal surfaces. {yields} Development of nanostructured powder paints. {yields} Characterization of the new material in the powder and coating form. {yields} Development of a new material for use in the automotive industry, industrial production of appliances, furniture industry. {yields} Development of new material using the process of mixing using a twin-screw extruder, followed by sintering process on a metal plate. - Abstract: The incorporation of nanoclays into coatings has been considered to be commercially favorable due to the improvements obtained in the barrier, thermal, and anticorrosion properties, among others, leading to the development of a new segment in the area of clean technologies: the application of nanocomposites to powder coatings. In this study, in order to compare the performance of a powder coating with the addition of a conventional load (barium sulfate) and a montmorillonite clay (MMT), two mixtures of commercial epoxy-based powder coating were prepared in the melt state, with the addition of 2 and 4% (w/w) of MMT, or 2 and 4% (w/w) of barium sulfate (BaSO{sub 4}). The thermal properties were investigated through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to evaluate the load dispersion and the morphology of the systems formed. The physical and anticorrosion properties of the coatings were also investigated. The interaction of the MMT with the polymeric matrix, associated to the aspect ratio, resulted in better barrier properties, thermal stability, and adhesion to the metal substrate.

  18. Effect of Sonification Time on Synthesisi and Corrosion Resistance of Epoxy-Clay Nanocomposite

    Directory of Open Access Journals (Sweden)

    Niloufar Bahrami Panah

    2016-09-01

    Full Text Available In recent years many research works have been carried out on anti-corrosive nanocomposites coatings containing mineral reinforcements. The most important criteria in these attempts are polymerization method and the type of matrix and reinforcement of nanocomposites. In this regard, the physical and mechanical properties of the polymers in which a small amount of filler is used can be improved. In this research, an epoxy-clay nanocomposite was synthesized by in-situ polymerization method using a resin matrix based on bisphenol-A type epoxy and montmorillonite clay (Closite 15A. The treatment was used at different ultrasonic stirring times to disperse 1-4 weight percentages of clay particles into the matrix. The structure of synthesized epoxy-clay nanocomposite was studied by scanning electron microscopy and X-ray diffraction techniques. The average size of clay particles was determined by X-ray diffraction measurement. Then, anti-corrosion properties of epoxy-clay coatings, prepared under different ultrasonic durations and applied on carbon steel panels, were investigated by Tafel and electrochemical impedance spectroscopy techniques. For this purpose, the carbon steel panels coated with these coatings were immersed in 3.5% sodium chloride solution and tested at different immersion times. The results indicated that a nanocomposite containing 1% clay, synthesized, stirred 60 min ultrasonically, produced smaller particle size, lower corrosion current density and higher coating corrosion resistance than the other composite formulations. This nanocomposite provided superior protection against corrosion in sodium chloride solution.

  19. Influence of nano-AlN particles on thermal conductivity, thermal stability and cure behavior of cycloaliphatic epoxy/trimethacrylate system

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available We have prepared a series of nano-sized aluminium nitride (nano-AlN/cycloaliphatic epoxy/trimethacrylate (TMPTMA systems and investigated their morphology, thermal conductivity, thermal stability and curing behavior. Experimental results show that the thermal conductivity of composites increases with the nano-AlN filler content, the maximum value is up to 0.47 W/(m.K. Incorporation of a small amount of the nano-AlN filler into the epoxy/TMPTMA system improves the thermal stability. For instance, the thermal degradation temperature at 5% weight loss of nano-AlN/epoxy/TMPTMA system with only 1 wt% nano-AlN was improved by ~8ºC over the neat epoxy/TMPTMA system. The effect of nano-AlN particles on the cure behavior of epoxy/TMPTMA systems was studied by dynamic differential scanning calorimetry. The results showed that the addition of silane treated nano-AlN particles does not change the curing reaction mechanism and silane treated nano-AlN particles could bring positive effect on the processing of composite since it needs shorter pre-cure time and lower pre-temperature, meanwhile the increase of glass transition temperature of the nanocomposite improves the heat resistance.

  20. Toughening Mechanisms in Silica-Filled Epoxy Nanocomposites

    Science.gov (United States)

    Patel, Binay S.

    Epoxies are widely used as underfill resins throughout the microelectronics industry to mechanically couple and protect various components of flip-chip assemblies. Generally rigid materials largely surround underfill resins. Improving the mechanical and thermal properties of epoxy resins to better match those of their rigid counterparts can help extend the service lifetime of flip-chip assemblies. Recently, researchers have demonstrated that silica nanoparticles are effective toughening agents for lightly-crosslinked epoxies. Improvements in the fracture toughness of silica-filled epoxy nanocomposites have primarily been attributed to two toughening mechanisms: particle debonding with subsequent void growth and matrix shear banding. Various attempts have been made to model the contribution of these toughening mechanisms to the overall fracture energy observed in silica-filled epoxy nanocomposites. However, disparities still exist between experimental and modeled fracture energy results. In this dissertation, the thermal, rheological and mechanical behavior of eight different types of silica-filled epoxy nanocomposites was investigated. Each nanocomposite consisted of up to 10 vol% of silica nanoparticles with particle sizes ranging from 20 nm to 200 nm, with a variety of surface treatments and particle structures. Fractographical analysis was conducted with new experimental approaches in order to accurately identify morphological evidence for each proposed toughening mechanism. Overall, three major insights into the fracture behavior of real world silica-filled epoxy nanocomposites were established. First, microcracking was observed as an essential toughening mechanism in silica-filled epoxy nanocomposites. Microcracking was observed on the surface and subsurface of fractured samples in each type of silica-filled epoxy nanocomposite. The additional toughening contribution of microcracking to overall fracture energy yielded excellent agreement between experimental

  1. Investigation of the cure behaviour of an epoxy polyester powder coating

    International Nuclear Information System (INIS)

    Ishrat, S.; Nadeem, M.

    1993-01-01

    The epoxy polyester based thermo sets make attractive matrix materials for many industrial and commercial applications because of their excellent performance properties. These properties for example, dimensional stability, adhesion, chemical resistance, and thermal stability arise primarily from the formation of crosslinks during cure. While many factors, such as the reactivity and stoichiometry of the reactants can influence the course of the crosslinking reaction, the cure temperature and cure time ultimately govern the end use performance of the thermosetting systems of powder coatings. The interrelationship between the network formation process and performance properties makes cure process studies critically important in product development. A products end use performance properties can be correlated with the processing conditions by monitoring specific polymeric properties such as gel points, glass transition temperature (TgS,) and the kinetics of the crosslinking reaction. By plotting the change in these properties against cure time and or cure temperature, a 'profile' or degree of cure (DOC) curve can be formed. These profiles illustrate the progress of the crosslinking reaction and can be used to optimize thermo set handling, processing and cure process. (author)

  2. Development of palm oil-based UV-curable epoxy acrylate and urethane acrylate resins for wood coating application

    International Nuclear Information System (INIS)

    Rida Tajau; Nurulhuda Mohd Yunus; Mohd Hilmi Mahmood; Mek Zah Salleh; Nik Ghazali Nik Salleh

    2013-01-01

    Full-text: The trend of using renewable sources such as palm oil as raw material in radiation curing is growing due to the demand from the market to produce a more environmental friendly product. In this study, the radiation curable process was done using epoxy acrylate and urethane acrylate resins which are known as epoxidized palm olein acrylate (EPOLA) and palm oil based urethane acrylate (POBUA), respectively. The purpose of the study was to investigate curing properties and the application of this UV-curable palm oil resins for wood coating. Furthermore, the properties of palm oil based coatings are compared with the petrochemical-based compound such as ebecryl (EB) for example EB264 and EB830. From the experiment done, the resins from petrochemical-based compounds resulted higher degree of crosslinking (up to 80 %) than the palm oil based compounds (up to 70 %), where the different is around 10-15 %. The hardness property from this two type coatings can reached until 50 % at the lower percentage of the oligomer. However, the coatings from petrochemical-based have a high scratch resistance as it can withstand at least up to 3.0 Newton's (N) compared to the palm oil-based compounds which are difficult to withstand the load up to 1.0 N. Finally, the test on the rubber wood substrate showed that the coatings containing benzophenone photo initiator give higher adhesion property and their also showed a higher glossiness property on the glass substrate compared to the coatings containing irgacure-819 photo initiator. This study showed that the palm oil coatings can be a suitable for the replacement of petrochemicals compound for wood coating. The palm oil coatings can be more competitive in the market if the problems of using high percentage palm oil oligomer can be overcome as the palm oil price is cheap enough. (author)

  3. Development of palm oil-based UV-curable epoxy acrylate and urethane acrylate resins for wood coating application

    International Nuclear Information System (INIS)

    Tajau, Rida; Mahmood, Mohd Hilmi; Salleh, Mek Zah; Salleh, Nik Ghazali Nik; Ibrahim, Mohammad Izzat; Yunus, Nurulhuda Mohd

    2014-01-01

    The trend of using renewable sources such as palm oil as raw material in radiation curing is growing due to the demand from the market to produce a more environmental friendly product. In this study, the radiation curable process was done using epoxy acrylate and urethane acrylate resins which are known as epoxidised palm olein acrylate (EPOLA) and palm oil based urethane acrylate (POBUA), respectively. The purpose of the study was to investigate curing properties and the application of this UV-curable palm oil resins for wood coating. Furthermore, the properties of palm oil based coatings are compared with the petrochemical-based compound such as ebecryl (EB) i.e. EB264 and EB830. From the experiment done, the resins from petrochemical-based compounds resulted higher degree of crosslinking (up to 80%) than the palm oil based compounds (up to 70%), where the different is around 10-15%. The hardness property from this two type coatings can reached until 50% at the lower percentage of the oligomer. However, the coatings from petrochemical-based have a high scratch resistance as it can withstand at least up to 3.0 Newtons (N) compared to the palm oil-based compounds which are difficult to withstand the load up to 1.0 N. Finally, the test on the rubber wood substrate showed that the coatings containing benzophenone photoinitiator give higher adhesion property and their also showed a higher glosiness property on the glass substrate compared to the coatings containing irgacure-819 photoinitiator. This study showed that the palm oil coatings can be a suitable for the replacement of petrochemicals compound for wood coating. The palm oil coatings can be more competitive in the market if the problems of using high percentage palm oil oligomer can be overcome as the palm oil price is cheap enough

  4. Development of palm oil-based UV-curable epoxy acrylate and urethane acrylate resins for wood coating application

    Energy Technology Data Exchange (ETDEWEB)

    Tajau, Rida; Mahmood, Mohd Hilmi; Salleh, Mek Zah; Salleh, Nik Ghazali Nik [Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor (Malaysia); Ibrahim, Mohammad Izzat [Faculty of Science, University of Malaya (UM), 50603 Kuala Lumpur (Malaysia); Yunus, Nurulhuda Mohd [Faculty of Science and Technology, National University Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2014-02-12

    The trend of using renewable sources such as palm oil as raw material in radiation curing is growing due to the demand from the market to produce a more environmental friendly product. In this study, the radiation curable process was done using epoxy acrylate and urethane acrylate resins which are known as epoxidised palm olein acrylate (EPOLA) and palm oil based urethane acrylate (POBUA), respectively. The purpose of the study was to investigate curing properties and the application of this UV-curable palm oil resins for wood coating. Furthermore, the properties of palm oil based coatings are compared with the petrochemical-based compound such as ebecryl (EB) i.e. EB264 and EB830. From the experiment done, the resins from petrochemical-based compounds resulted higher degree of crosslinking (up to 80%) than the palm oil based compounds (up to 70%), where the different is around 10-15%. The hardness property from this two type coatings can reached until 50% at the lower percentage of the oligomer. However, the coatings from petrochemical-based have a high scratch resistance as it can withstand at least up to 3.0 Newtons (N) compared to the palm oil-based compounds which are difficult to withstand the load up to 1.0 N. Finally, the test on the rubber wood substrate showed that the coatings containing benzophenone photoinitiator give higher adhesion property and their also showed a higher glosiness property on the glass substrate compared to the coatings containing irgacure-819 photoinitiator. This study showed that the palm oil coatings can be a suitable for the replacement of petrochemicals compound for wood coating. The palm oil coatings can be more competitive in the market if the problems of using high percentage palm oil oligomer can be overcome as the palm oil price is cheap enough.

  5. Dry sliding wear behavior of epoxy composite reinforced with short palmyra fibers

    International Nuclear Information System (INIS)

    Biswal, Somen; Satapathy, Alok

    2016-01-01

    The present work explores the possibility of using palmyra fiber as a replacement for synthetic fiber in conventional polymer composites for application against wear. An attempt has been made in this work to improve the sliding wear resistance of neat epoxy by reinforcing it with short palmyra fibers (SPF). Epoxy composites with different proportions (0, 4, 8 and 12 wt. %) of SPF are fabricated by conventional hand lay-up technique. Dry sliding wear tests are performed on the composite samples using a pin-on-disc test rig as per ASTM G 99-05 standards under various operating parameters. Design of experiment approach based on Taguchi's L16 Orthogonal Arrays is used for the analysis of the wear. This parametric analysis reveals that the SPF content is the most significant factor affecting the wear process followed by the sliding velocity. The sliding wear behavior of these composites under an extensive range of test conditions is predicted by a model based on the artificial neural network (ANN). A well trained ANN has been used to predict the sliding wear response of epoxy based composites over a wide range. (paper)

  6. On-Chip Bondwire Magnetics with Ferrite-Epoxy Glob Coating for Power Systems on Chip

    Directory of Open Access Journals (Sweden)

    Jian Lu

    2008-01-01

    Full Text Available A novel concept of on-chip bondwire inductors and transformers with ferrite epoxy glob coating is proposed to offer a cost effective approach realizing power systems on chip (SOC. We have investigated the concept both experimentally and with finite element modeling. A Q factor of 30–40 is experimentally demonstrated for the bondwire inductors which represents an improvement by a factor of 3–30 over the state-of-the-art MEMS micromachined inductors. Transformer parameters including self- and mutual inductance and coupling factors are extracted from both modeled and measured S-parameters. More importantly, the bondwire magnetic components can be easily integrated into SOC manufacturing processes with minimal changes and open enormous possibilities for realizing cost-effective, high-current, high-efficiency power SOCs.

  7. The optimal structure-conductivity relation in epoxy-phthalocyanine nanocomposites.

    Science.gov (United States)

    Huijbregts, L J; Brom, H B; Brokken-Zijp, J C M; Kemerink, M; Chen, Z; Goeje, M P de; Yuan, M; Michels, M A J

    2006-11-23

    Phthalcon-11 (aquocyanophthalocyaninatocobalt (III)) forms semiconducting nanocrystals that can be dispersed in epoxy coatings to obtain a semiconducting material with a low percolation threshold. We investigated the structure-conductivity relation in this composite and the deviation from its optimal realization by combining two techniques. The real parts of the electrical conductivity of a Phthalcon-11/epoxy coating and of Phthalcon-11 powder were measured by dielectric spectroscopy as a function of frequency and temperature. Conducting atomic force microscopy (C-AFM) was applied to quantify the conductivity through the coating locally along the surface. This combination gives an excellent tool to visualize the particle network. We found that a large fraction of the crystals is organized in conducting channels of fractal building blocks. In this picture, a low percolation threshold automatically leads to a conductivity that is much lower than that of the filler. Since the structure-conductivity relation for the found network is almost optimal, a drastic increase in the conductivity of the coating cannot be achieved by changing the particle network, but only by using a filler with a higher conductivity level.

  8. Optical emission behavior and radiation resistance of epoxy resins

    International Nuclear Information System (INIS)

    Kawanishi, Shunichi; Udagawa, Akira; Hagiwara, Miyuki

    1987-11-01

    To make clear a mechanism of radiation resistance of epoxy resin systems, a role of energy trapping site induced in bisphenol A type epoxy resins cured with 4 kinds of aromatic amines (Φ N ) was studied in comparison with the case of aliphatic amine curing system through a measurement of optical emission. In the system of the epoxy resin cured with DETA, the optical emission from an excited state of bisphenol A unit of epoxy resin and a charge transfer complex was observed. On the other hand, the optical emission from Φ N was observed in the aromatic amine curing system. Their excitation spectrum consists of peaks of absorption spectrum of BA and those of Φ N , showing that the excited state of Φ N is formed through the excitation of both BA and Φ N . Therefore, the excited energy of BA transfers to the excited state of Φ N . Emission intensity of Φ N band was 20 ∼ 100 times as large as that of BA. These results indicate that the radiation energy is effectively released as an optical emission from excited state of Φ N in the epoxy resin when cured with aromatic amine. It can be concluded from the above results that aromatic amine hardeners contribute to enhancement of the radiation resistance of epoxy resin by acting as an energy transfer agent. (author)

  9. Influence of particle surface properties on the dielectric behavior of silica/epoxy nanocomposites

    International Nuclear Information System (INIS)

    Cheng Lihong; Zheng Liaoying; Li Guorong; Zeng Jiangtao; Yin Qingrui

    2008-01-01

    Silica/epoxy composites have been widely used in functional electric device applications. Silica nanoparticles, both unmodified and modified with the coupling agent KH-550, were used to prepare epoxy composites. Dielectric measurements showed that nanocomposites exhibit a higher dielectric constant than the control sample, and had more obvious dielectric relaxation characteristics. Results showed that particle surface properties have a profound effect on the dielectric behavior of the nanocomposites. These characteristics are attributed to the local ununiformity of the microstructure caused by the large interface area and the interaction between the filler and the matrix. This phenomenon is explained in terms of prolonging chemical chains created during the curing process. The mechanism is discussed with measurements of X-ray diffraction (XRD) and Fourier transform infrared (FTIR)

  10. Processing and properties of carbon nanofibers reinforced epoxy powder composites

    International Nuclear Information System (INIS)

    Palencia, C.; Mazo, M. A.; Nistal, A.; Rubio, F.; Rubio, J.; Oteo, J. L.

    2011-01-01

    Commercially available CNFs (diameter 30–300 nm) have been used to develop both bulk and coating epoxy nanocomposites by using a solvent-free epoxy matrix powder. Processing of both types of materials has been carried out by a double-step process consisting in an initial physical premix of all components followed by three consecutive extrusions. The extruded pellets were grinded into powder and sieved. Carbon nanofibers powder coatings were obtained by electrostatic painting of the extruded powder followed by a curing process based in a thermal treatment at 200 °C for 25 min. On the other hand, for obtaining bulk carbon nanofibers epoxy composites, a thermal curing process involving several steps was needed. Gloss and mechanical properties of both nanocomposite coatings and bulk nanocomposites were improved as a result of the processing process. FE-SEM fracture surface microphotographs corroborate these results. It has been assessed the key role played by the dispersion of CNFs in the matrix, and the highly important step that is the processing and curing of the nanocomposites. A processing stage consisted in three consecutive extrusions has reached to nanocomposites free of entanglements neither agglomerates. This process leads to nanocomposite coatings of enhanced properties, as it has been evidenced through gloss and mechanical properties. A dispersion limit of 1% has been determined for the studied system in which a given dispersion has been achieved, as the bending mechanical properties have been increased around 25% compared with the pristine epoxy resin. It has been also demonstrated the importance of the thickness in the nanocomposite, as it involves the curing stage. The complex curing treatment carried out in the case of bulk nanocomposites has reached to reagglomeration of CNFs.

  11. Processing and properties of carbon nanofibers reinforced epoxy powder composites

    Science.gov (United States)

    Palencia, C.; Mazo, M. A.; Nistal, A.; Rubio, F.; Rubio, J.; Oteo, J. L.

    2011-11-01

    Commercially available CNFs (diameter 30-300 nm) have been used to develop both bulk and coating epoxy nanocomposites by using a solvent-free epoxy matrix powder. Processing of both types of materials has been carried out by a double-step process consisting in an initial physical premix of all components followed by three consecutive extrusions. The extruded pellets were grinded into powder and sieved. Carbon nanofibers powder coatings were obtained by electrostatic painting of the extruded powder followed by a curing process based in a thermal treatment at 200 °C for 25 min. On the other hand, for obtaining bulk carbon nanofibers epoxy composites, a thermal curing process involving several steps was needed. Gloss and mechanical properties of both nanocomposite coatings and bulk nanocomposites were improved as a result of the processing process. FE-SEM fracture surface microphotographs corroborate these results. It has been assessed the key role played by the dispersion of CNFs in the matrix, and the highly important step that is the processing and curing of the nanocomposites. A processing stage consisted in three consecutive extrusions has reached to nanocomposites free of entanglements neither agglomerates. This process leads to nanocomposite coatings of enhanced properties, as it has been evidenced through gloss and mechanical properties. A dispersion limit of 1% has been determined for the studied system in which a given dispersion has been achieved, as the bending mechanical properties have been increased around 25% compared with the pristine epoxy resin. It has been also demonstrated the importance of the thickness in the nanocomposite, as it involves the curing stage. The complex curing treatment carried out in the case of bulk nanocomposites has reached to reagglomeration of CNFs.

  12. The role of the substrate in micro-scale scratching of epoxy-polyester films

    Science.gov (United States)

    Barletta, M.; Gisario, A.

    2011-02-01

    The present investigation analyzes the deformation response of electrostatically sprayed epoxy-polyester powder coatings by 'in situ' micro-mechanical tests. The characterization of the performance of the coatings was carried out by micro-scale scratching, by varying the indenter type, the applied load and the sliding speed. The tests were carried out on polymeric coatings deposited on as-received, micro and macro-corrugated AISI 304 stainless steel substrates and 'rigidly adhered' to them. Further tests were performed on 'free-standing' coatings, that is, on the as-received metal substrates pre-coated with an intermediate layer of silicon-based heat curable release coating. Experimental data allow us to evaluate the influence of the contact conditions between substrate and indenter and the role of the loading conditions on the scratch and penetration resistance of the epoxy-polyester coatings. The different responses of the polymeric coatings when deposited on untreated or pre-treated substrates as well as on an intermediate layer of release coating, contribute to a better understanding of the intrinsic roles of the polymeric material and substrate as well as the influence of the interfacial adhesion between coating and substrate.

  13. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Science.gov (United States)

    Periolatto, M.; Sangermano, M.; Spena, P. Russo

    2016-05-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  14. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Periolatto, M.; Spena, P. Russo [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano (Italy); Sangermano, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino (Italy)

    2016-05-18

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  15. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    International Nuclear Information System (INIS)

    Periolatto, M.; Spena, P. Russo; Sangermano, M.

    2016-01-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  16. Epoxy-coal hydraulic insulation for structures of the Nurek Hydroelectric Powerplant

    Energy Technology Data Exchange (ETDEWEB)

    Sakharov, V I; Segal, M S; Solov' ev, I N; Yazev, R E

    1978-03-01

    The design of the Nurek Powerplant exposed the base of the core of the dam to a head of 270 m. To avoid seepage, it was decided to construct an antiseepage screen. Given the total hydraulic insulation area required, 26,540 m/sup 2/, the use of a metal screen would be quite expensive. It was therefore decided to use an epoxy-coal material consisting of a primer, varnish and enamel based on epoxy resins modified by the addition of coal tar, a waste product from the dry distillation of coal. A typical hydraulic insulation layer consists of a coat of primer, three or four coats of varnish and a coat of enamel. Glass-reinforced fabric is used with the first through third coats of varnish to increase crack resistance. The coating thus produced is found to be resistant to overbearing soil pressure of up to 600 t/m/sup 2/, hydrostatic head of up to 300 m and constant shear forces of up to 100 t/m/sup 2/. The method also saves labor and expensive metal.

  17. The effect of strain-rate on the tensile and compressive behavior of graphene reinforced epoxy/nanocomposites

    International Nuclear Information System (INIS)

    Shadlou, Shahin; Ahmadi-Moghadam, Babak; Taheri, Farid

    2014-01-01

    Highlights: • The epoxy/graphene nanocomposites were studied at various strain rates. • The variations in constitutive stress–strain response were scrutinized. • Positive reinforcing attributes of graphene diminished at higher strain rates. • Graphene particles have higher efficiency under compression loading than tension. • A new modification factor for Halpin–Tsai model was proposed. - Abstract: The effect of strain rate on the mechanical behavior of epoxy reinforced with graphene nanoplatelets (GNPs) is investigated. Nanocomposites containing various amounts of GNP are prepared and tested at four different strain rates (0.01, 0.1, 1 and 10/s) under compressive and tensile loading regimes. The results show that incorporation of GNP highly affects the behavior of epoxy. The fracture surfaces of tensile specimens are also investigated using scanning electron microscopy (SEM) to discern the surface features and dispersion state of GNP. Finally, the predictive capability of some of the available models for evaluating the strength of nanocomposites are assessed and compared against the experimental results. Moreover, a modification factor to the widely used Halpin–Tsai model is proposed to improve the accuracy of the model when evaluating the Young’s modulus of nanocomposites at various strain rates

  18. Curing behavior and thermal properties of trifunctional epoxy resin cured by 4, 4’-diaminodiphenyl sulfone

    Directory of Open Access Journals (Sweden)

    2009-08-01

    Full Text Available A novel trifunctional epoxy resin 4-(3, 3-dihydro-7-hydroxy-2, 4, 4-trimethyl-2H-1-benzopyran-2-yl-1, 3-benzenediol glycidyl (shorted as TMBPBTH-EPOXY was synthesized in our lab to improve thermal performance. Its curing behavior and performance were studied by using 4, 4′-diaminodiphenyl sulfone (DDS as hardener with the mass ratio of 100:41 of TMBPBTH-EPOXY and DDS. The curing activation energy was investigated by differential scanning calorimetry (DSC to be 64.0 kJ/mol estimated by Kissinger’s method and 68.7 kJ/mol estimated by Flynn-Wall-Ozawa method respectively. Thermogravimetric analyzer (TGA was used to investigate the thermal decomposition of cured compounds. It was found that when curing temperature was lower than 180°C, the thermal decomposition temperature increased with the rise of curing temperature and curing time. On the other hand, when the curing temperature was higher than 180°C, the thermal decomposition temperature went down instead with the increase of curing time that might be the over-crosslinking of TMBPBTH-EPOXY and DDS hardener. The glass transition temperature (Tg of cured TMBPBTH-EPOXY/DDS compound determined by dynamic mechanical thermal analysis (DMTA is 290.1°C.

  19. Solid-state fractional capacitor using MWCNT-epoxy nanocomposite

    Science.gov (United States)

    John, Dina A.; Banerjee, Susanta; Bohannan, Gary W.; Biswas, Karabi

    2017-04-01

    Here, we propose the fabrication of a solid state fractional capacitor for which constant phase (CP) angles were attained in different frequency zones: 110 Hz-1.1 kHz, 10 kHz-118 kHz, and 230 kHz-20 MHz. The configuration makes use of epoxy resin as the matrix in which multi-walled carbon nanotubes (MWCNTs) are dispersed. Adhesive nature of the epoxy resin is utilized for binding the electrodes, which avoids the extra step for packaging. The fractional capacitive behavior is contributed by the distribution of time constants for the electron to travel from one electrode to the other. The distributive nature of the time constant is ensured by inserting a middle plate which is coated with a porous film of polymethyl-methacrylate in between the two electrodes. The phase angle trend for the configuration is studied in detail, and it is observed that as the % of carbon nanotubes (CNTs) loading increases, the CP angle increases from - 85 ° to - 45 ° in the frequency zones above 100 Hz. The developed device is compact and it can be easily integrated with the electronic circuits.

  20. Evaluation of Tritium Behavior in the Epoxy Painted Concrete Wall of ITER Hot Cell

    International Nuclear Information System (INIS)

    Nakamura, Hirofumi; Hayashi, Takumi; Kobayashi, Kazuhiro; Nishi, Masataka

    2005-01-01

    Tritium behavior released in the ITER hot cell has been investigated numerically using a combined analytical methods of a tritium transport analysis in the multi-layer wall (concrete and epoxy paint) with the one dimensional diffusion model and a tritium concentration analysis in the hot cell with the complete mixing model by the ventilation. As the results, it is revealed that tritium concentration decay and permeation issues are not serious problem in a viewpoint of safety, since it is expected that tritium concentration in the hot cell decrease rapidly within several days just after removing the tritium release source, and tritium permeation through the epoxy painted concrete wall will be negligible as long as the averaged realistic diffusion coefficient is ensured in the concrete wall. It is also revealed that the epoxy paint on the concrete wall prevents the tritium inventory increase in the concrete wall greatly (two orders of magnitudes), but still, the inventory in the wall is estimated to reach about 0.1 PBq for 20 years operation

  1. The study of epoxy polyamide and polyvinyl resins as corrosion ...

    African Journals Online (AJOL)

    The corrosion resistance of two commonly used protective coatings (epoxy polyamide and polyvinyl resins) in the Niger Delta area of Nigeria has been assessed. The coatings on low carbon steel were subjected to varying conditions of pH, temperature and exposure time and the corrosion rates calculated. At a pH of 2, 3, 4, ...

  2. The effect of carbon nanotube dimensions and dispersion on the fatigue behavior of epoxy nanocomposites

    International Nuclear Information System (INIS)

    Zhang, W; Picu, R C; Koratkar, N

    2008-01-01

    Fatigue is one of the primary reasons for failure in structural materials. It has been demonstrated that carbon nanotubes can suppress fatigue in polymer composites via crack-bridging and a frictional pull-out mechanism. However, a detailed study of the effects of nanotube dimensions and dispersion on the fatigue behavior of nanocomposites has not been performed. In this work, we show the strong effect of carbon nanotube dimensions (i.e. length, diameter) and dispersion quality on fatigue crack growth suppression in epoxy nanocomposites. We observe that the fatigue crack growth rates can be significantly reduced by (1) reducing the nanotube diameter, (2) increasing the nanotube length and (3) improving the nanotube dispersion. We qualitatively explain these observations by using a fracture mechanics model based on crack-bridging and pull-out of the nanotubes. By optimizing the above parameters (tube length, diameter and dispersion) we demonstrate an over 20-fold reduction in the fatigue crack propagation rate for the nanocomposite epoxy compared to the baseline (unfilled) epoxy

  3. Effect of hydrophobic paints coating for tritium reduction in concrete materials

    International Nuclear Information System (INIS)

    Edao, Y.; Fukada, S.; Nishimura, Y.; Katayama, K.; Takeishi, T.; Hatano, Y.; Taguchi, A.

    2012-01-01

    Highlights: ► Effects of hydrophobic paint coating in tritium transport are investigated. ► Two kinds of paints, acrylic-silicon resin and epoxy resin are used. ► The hydrophobic paints are effective to reduce tritium permeation. ► The effect of tritium reduction of epoxy paint is higher than that of silicon. - Abstract: The effects of hydrophobic paint coating on a concrete material of cement paste on the tritium transport are investigated. The cement paste is coated with two kinds of paints, acrylic-silicon resin paint and epoxy resin paint. We investigated the amount of tritium trapped in the samples exposed to tritiated water vapor by means of sorption and release. It was found that both the hydrophobic paints could reduce effectively tritium permeation during 50 days exposure of tritiated water vapor. The effect of tritium reduction of the epoxy paint was higher than that of silicon while the amount of tritium trapped in the epoxy paint was larger than that of silicon due to difference of the structure. Based on an analysis of a diffusion model, the rate-determining step of tritium migration through cement paste coated with the paints is diffusion through the paints respectively. It was found that tritium was easy to penetrate through silicon because there were many pores or voids in the silicon comparatively. In the case of tritium released from the epoxy paint, it is considered that tritium diffusion in epoxy is slow due to retardation by isotope exchange reaction to water included in epoxy paint.

  4. Investigation of Thermal Behavior for Natural Fibres Reinforced Epoxy using Thermogravimetric and Differential Scanning Calorimetric Analysis

    Directory of Open Access Journals (Sweden)

    Fauzi F.A.

    2016-01-01

    Full Text Available This paper presented the research works on the investigation of the thermal behavior of the natural fibres; i.e. pineapple leaf fibre, kenaf fibre and mengkuang fibres reinforced epoxy. The thermogravimetric analysis and differential scanning calorimetric analysis were used to measure the thermal behavior of the treated and untreated pineapple, kenaf and mengkuang fibres reinforced epoxy. The samples for both analysis were subjected to maximum temperature 600°C at the heating rate of 10°C/min. The results showed that the treated fibres show higher maximum peak temperature as compared to the untreated fibres. Additionally, the glass transition temperature showed a lower value for all treated fibre. It can be concluded that investigation of thermal properties of these natural fibres could improve the utilization of natural fibre composites in various applications i.e. sports applications.

  5. Behavior of an epoxy-polysulfide adhesive in wood joints exposed to moisture content changes

    Science.gov (United States)

    Gordon P. Krueger

    1965-01-01

    The mechanical behavior of a flexible epoxy-resin adhesive system was observed in joints of plywood to lumber. The joints were subjected to internal swelling stresses caused by an increase in moisture content. Previous experimental work at the U.S. Forest Products Laboratory has shown that this adhesive system acts as a strain-absorbing cushion and thus has a...

  6. The optimal structure-conductivity relation in epoxy-phthalocyanine nanocomposites

    NARCIS (Netherlands)

    Huijbregts, L.J.; Brom, H.B.; Brokken-Zijp, J.C.M.; Kemerink, M.; Chen, Z.; Goeje, de M.P.; Yuan, M.; Michels, M.A.J.

    2006-01-01

    Phthalcon-11 (aquocyanophthalocyaninatocobalt (III)) forms semiconducting nanocrystals that can be dispersed in epoxy coatings to obtain a semiconducting material with a low percolation threshold. We investigated the structure-cond. relation in this composite and the deviation from its optimal

  7. Stress Analysis in Polymeric Coating Layer Deposited on Rigid Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Soon Lee [Korea University of Technology and Education, School of Mechatronics Engineering, Chonan (Korea, Republic of)

    2015-08-15

    This paper presents an analysis of thermal stress induced along the interface between a polymeric coating layer and a steel substrate as a result of uniform temperature change. The epoxy layer is assumed to be a linear viscoelastic material and to be theromorheologically simple. The viscoelastic boundary element method is employed to investigate the behavior of interface stresses. The numerical results exhibit relaxation of interface stresses and large stress gradients, which are observed in the vicinity of the free surface. Since the exceedingly large stresses cannot be borne by the polymeric coating layer, local cracking or delamination can occur at the interface corner.

  8. Studies on preparation and properties of the multi-walled carbon nanotubes (MWNTs)/epoxy nanocomposites

    International Nuclear Information System (INIS)

    Deng Huayang; Cao Qi; Wang Xianyou; Chen Quanqi; Kuang Hao; Wang Xiaofeng

    2011-01-01

    Highlights: → We use the modified MWNTs as fillers fabricated epoxy nanocomposites. → The mechanical, thermal and dielectric properties of nanocomposites are measured. → The nanocomposites exhibited better mechanical and dielectric properties. - Abstract: The MWNTs were coated with polyaniline (PANI) by in situ chemical oxidation polymerization method. FTIR spectroscopy, scanning electron microscope (SEM) and X-ray diffraction (XRD) indicated that the MWNTs were coated with PANI. The MWNTs/epoxy nanocomposites were fabricated by using the solution blending method. Differential scanning calorimetry (DSC), tensile testing, HP 4294A impedance analyzer and SEM were used to investigate the properties of the nanocomposites. The results showed that the modified carbon nanotubes were well dispersed in the polymer matrix. The nanocomposites have enhancements in mechanical, thermal and dielectric properties compare with the neat epoxy resin. The nanocomposites were proven to be a good polymer dielectric material.

  9. UNDERWATER COATINGS FOR CONTAMINATION CONTROL

    International Nuclear Information System (INIS)

    Julia L. Tripp; Kip Archibald; Ann Marie Phillips; Joseph Campbell

    2004-01-01

    The Idaho National Laboratory (INL) deactivated several aging nuclear fuel storage basins. Planners for this effort were greatly concerned that radioactive contamination present on the basin walls could become airborne as the sides of the basins became exposed during deactivation and allowed to dry after water removal. One way to control this airborne contamination was to fix the contamination in place while the pool walls were still submerged. There are many underwater coatings available on the market for marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives were easily applied and adhered well to the substrates (pool wall materials) found in INL fuel pools. Lab-scale experiments were conducted by applying fourteen different commercial underwater coatings to four substrate materials representative of the storage basin construction materials, and evaluating their performance. The coupons included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The evaluation criteria included ease of application, adherence to the four surfaces of interest, no change on water clarity or chemistry, non-hazardous in final applied form and be proven in underwater applications. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates was selected from the underwater coatings tested for application to all four pools. Divers scrubbed loose contamination off the basin walls and floors using a ship hull scrubber and vacuumed up the sludge. The divers then applied the coating using a special powered roller with two separate heated hoses that allowed the epoxy to mix at the roller surface was used to eliminate pot time concerns. The walls were successfully coated and water was removed from the pools with no detectable airborne contamination releases

  10. Bio-Based Aromatic Epoxy Monomers for Thermoset Materials

    Directory of Open Access Journals (Sweden)

    Feifei Ng

    2017-01-01

    Full Text Available The synthesis of polymers from renewable resources is a burning issue that is actively investigated. Polyepoxide networks constitute a major class of thermosetting polymers and are extensively used as coatings, electronic materials, adhesives. Owing to their outstanding mechanical and electrical properties, chemical resistance, adhesion, and minimal shrinkage after curing, they are used in structural applications as well. Most of these thermosets are industrially manufactured from bisphenol A (BPA, a substance that was initially synthesized as a chemical estrogen. The awareness on BPA toxicity combined with the limited availability and volatile cost of fossil resources and the non-recyclability of thermosets implies necessary changes in the field of epoxy networks. Thus, substitution of BPA has witnessed an increasing number of studies both from the academic and industrial sides. This review proposes to give an overview of the reported aromatic multifunctional epoxide building blocks synthesized from biomass or from molecules that could be obtained from transformed biomass. After a reminder of the main glycidylation routes and mechanisms and the recent knowledge on BPA toxicity and legal issues, this review will provide a brief description of the main natural sources of aromatic molecules. The different epoxy prepolymers will then be organized from simple, mono-aromatic di-epoxy, to mono-aromatic poly-epoxy, to di-aromatic di-epoxy compounds, and finally to derivatives possessing numerous aromatic rings and epoxy groups.

  11. Evolution of microstructure of epoxy coating during UV degradation progress studied by slow positron annihilation spectroscopy and electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Liu, Fuwei; Yin, Mingxi; Xiong, Bangyun; Zheng, Feng; Mao, Wenfeng; Chen, Zhe; He, Chunqing; Zhao, Xipo; Fang, Pengfei

    2014-01-01

    Graphical abstract: - Highlights: • Decrements in S value and water uptake coefficient confirm the post-cure process. • Molecular chain scission leads to the formation of microporous structure. • The formation of an aged layer with high density is verified by EIS. - Abstract: Evolution of chemical functional groups, microstructure and water barrier properties of a polyamide-cured epoxy (diglycidyl ether of bisphenol-A epoxy resin, DGEBA) coating during ultraviolet A (UV-A) photo-oxidative aging is systematically investigated. At the early stage of aging, decrements of S parameter and water uptake coefficient indicate the formation of a more compact structure induced by the post-curing process. After 208 hours (h) of UV irradiation, a novel time constant at relatively high frequency (3.5 × 10 2 Hz) appears in the electrochemical impedance spectroscopy (EIS) spectra suggesting that a microporous layer generates near the surface of DGEBA film. With the increase in irradiation time, overlap of two time constants at frequencies around 18 Hz and 3.7 × 10 3 Hz is observed after 1.33 h of immersion, indicating that the micropores grow towards the bulk and form more characteristic layers with microporous structures. After irradiation for 399 h, a low S parameter region near the sample surface is observed, which implies that a surface layer with low free volume may have formed. With longer exposure, EIS results also reveal that the water barrier property of the coating can be improved, which confirms the formation of the denser surface layer near the surface as a result of radical recombination during UV-A treatment

  12. Hygrothermal influence on delamination behavior of graphite/epoxy laminates

    Science.gov (United States)

    Garg, A.; Ishai, O.

    1985-01-01

    The hygrothermal effect on the fracture behavior of graphite-epoxy laminates was investigated to develop a methodology for damage tolerance predictions in advanced composite materials. Several T300/934 laminates were tested using a number of specimen configurations to evaluate the effects of temperature and humidity on delamination fracture toughness under mode 1 and mode 2 loading. It is indicated that moisture has a slightly beneficial influence on fracture toughness or critical strain energy release rate during mode 1 delamination, but has a slightly deleterious effect on mode 2 delamination, and mode 1 transverse cracking. The failed specimens are examined by SEM and topographical differences due to fracture modes are identified. It is concluded that the effect of moisture on fracture topography can not be distinguished.

  13. Color stability of esthetic coatings applied to nickel-titanium archwires

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Neiva Nunes do REGO

    Full Text Available Abstract Introduction Color stability is an important feature to be considered when using esthetic coated archwires. Objective To evaluate color changes on the surface of esthetic nickel-titanium archwires coated with Teflon (Ortho Organizers, USA or epoxy resin (Tecnident, Brazil after immersion in staining solution. Material and method Twelve 20-mm-long wire segments were used for each type of coating, which were mounted as two test specimens with a width of 7 mm each. The buccal surface of the archwires was evaluated for fluorescence and color measurements both at baseline and after immersion in a staining solution for 21 days using the VITA Easyshade® Compact spectrophotometer (Model DEASYC220. Differences in total color change according to coating type were compared using an independent samples t-test (p<0.05. The surface characteristics of as-received coated archwires were assessed using scanning electron microscopy. Result Color changes were observed on the esthetic coatings, with a significant difference between the two brands analyzed. Surface analysis revealed flaws such as wear, pitting, elevations, lack of material, granulation, grooves, cracks, and lack of standardization in the coating process in all as-received archwires, but flaws were less evident in epoxy-resin coatings. Conclusion The two esthetic coatings did not show color stability, but Teflon coatings showed a more intense color change than epoxy-resin coatings.

  14. Numerical study on the thermal behavior of graphene nanoplatelets/epoxy composites

    Science.gov (United States)

    Xiao, Wenkai; Zhai, Xian; Ma, Pengfei; Fan, Taotao; Li, Xiaotuo

    2018-06-01

    A three-dimensional computational model was developed using the finite element method (FEM) to evaluate the thermal behavior of graphene nanoplatelets (GNPs)/epoxy composites based on continuum mechanics. The model was validated with experimental data. The effects of the ratio of radius to thickness (Rrt) of GNPs, the interfacial thermal conductivity between GNPs and the matrix (Cgm), the contact thermal conductivity between GNPs (Cgg) and the agglomeration degree of GNPs on the thermal conductivity of composites (Kc) were quantified using this model. The results show that a larger Rrt is beneficial to Kc. GNPs could increase Kc only when the Cgm is greater than a critical value. A percolation phenomenon will occur when Cgg is larger than 1.0E8 W/(m2k) in randomly distributed GNPs/epoxy composites. The percolation effects become more obvious with the increase of Cgg and the volume fraction of GNPs. The agglomeration of GNPs has negative effects on the Kc. The higher the agglomeration degree of GNPs is, the lower Kc is. This is attributed to less beneficial interfacial areas, more inefficient contact areas, smaller Rrt and less effective connection/contact between GNPs.

  15. Nanosilica reinforced epoxy floor coating composites: preparation and thermophysical characterization

    Directory of Open Access Journals (Sweden)

    Mir Mohammad Alavi Nikje

    2012-01-01

    Full Text Available In this study, flooring grade epoxy/nanoSiO2 nanocomposites were prepared by in-situ polymerization method. Nano silica was treated by coupling agent in order to surface treating and introducing of reactive functional groups to achieving adequate bonding between polar inorganic nano particles and epoxy organic polymer. γ-Aminopropyltriethoxysilane (Amino A-100 was used as an effective and commercially available coupling agent and nano silica treated in acetone media. SEM observations of cured samples revealed that the nano silica was completely dispersed into polymer matrix into nanoscale particles. Thermal and physical properties of prepared samples were investigated and data showed improvements in physical and mechanical properties of the flooring samples in comparison with unfilled resin.

  16. Fabrication, performance, and figure metrology of epoxy-replicated aluminum foils for hard x-ray focusing multilayer-coated segmented conical optics

    DEFF Research Database (Denmark)

    Jimenez-Garate, M.A.; Craig, W.W.; Hailey, C.J.

    2000-01-01

    We fabricated x-ray mirrors for hard x-ray (greater than or equal to 10 keV) telescopes using multilayer coatings and an improved epoxy-replicated aluminum foil (ERAF) nonvacuum technology. The ERAF optics have similar to1 arcmin axial figure half-power diameter (HPD) and passed environmental...... telescope HPD, we designed a figure metrology system and a new mounting technique. We describe a cylindrical metrology system built for fast axial and roundness figure measurement of hard x-ray conical optics. These developments lower cost and improve the optics performance of the HEFT (high-energy focusing...

  17. Adhesion and corrosion studies of a lithium based conversion coating film on the 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Castro, M.R.S.; Nogueira, J.C.; Thim, G.P.; Oliveira, M.A.S.

    2004-01-01

    AA2024-T3-aluminum alloy surfaces were coated using non-chromate and chromate conversion coatings. All coatings were painted with the 10P4-2-primer epoxy resin. Independent on the film formation process, films passed on the substrate/conversion coating wet tape adhesion test. However, only the chromate conversion coating passed on the conversion coating/primer epoxy resin adhesion test. Electrochemical corrosion measurements showed that non-chromate conversion coated surfaces present lower corrosion current density, bigger polarization resistance and less negative corrosion potential than chromate conversion coated surfaces

  18. Use of 2,5-dimethyl-2,5-hexane diamine as a curing agent for epoxy resins. [Patent application

    Science.gov (United States)

    Rinde, J.A.; Newey, H.A.

    Primary diamines are prepared for use as a curing agent for epoxy resins. These curing agents can be used to form epoxy resin mixtures useful in filament winding and preimpregnated fiber molding and in formulating film adhesives, powder coatings and molding powders. The epoxy mixtures form for such uses a room temperature non-reacting, intermediate stable state which has a latent cross-linking capability.

  19. Corrosion resistance of rigid bonded magnet MQP-0 (NdFeB compound) pre and post surface coating

    International Nuclear Information System (INIS)

    Purwanto, Setyo; Ihsan, M.; Mujamilah; Mashadi

    2002-01-01

    Rigid Bonded Magnet (RBM) MQP-0 (NdFeB magnetics material compound) has been created and done some treatment. It has been known that corrosion resistance of RBM with epoxy resin binder is higher than RBM with polyester binder (PE). Corrosion rate in variety solutions like water. Na CI, H 2 SO 4 , has proved the earlier statement. For corrosion testing of RBM in Na CI solution with concentrations 0.05 M and 0.10 M shows corrosion rate 0.18 milli inches/year (mpy) and 2.93 mpy for epoxy binder, and 4.10 mpy and 24.87 mpy for polyester binder. In order to enhance the corrosion resistance, coating of RBM with epoxy resin has been done. And it has been known that coating of RBM with epoxy resin decrease of corrosion rate almost 50%. Corrosion rate of RBM with epoxy coating in 0.15 M Na CI is 9.38 mpy, compared without coating 15.11 mpy

  20. Influence of nanoclay particles modification by polyester-amide hyperbranched polymer on the corrosion protective performance of the epoxy nanocomposite

    International Nuclear Information System (INIS)

    Ganjaee Sari, M.; Ramezanzadeh, B.; Shahbazi, M.; Pakdel, A.S.

    2015-01-01

    Highlights: • Nanoclay particles were modified with polyester-amide hyperbranched polymer. • Epoxy/clay nanocomposites were prepared using modified clay particles. • Surface modification enhanced the clay particles exfoliation properties. • Surface modified clay particles enhanced corrosion resistance of the epoxy coating. - Abstract: Surface modification of nanoclay particles was carried out by various amounts of polyester-amide hyperbranched polymer (HBP). Thermal gravimetric analysis and X-ray diffraction analysis were performed to estimate the efficiency of the HPB grafting on the clay particles. Epoxy/clay nanocomposites were prepared by addition of 1 wt.% unmodified and modified clays. The corrosion protection properties of the nanocomposites were evaluated by electrochemical impedance spectroscopy (EIS). Results revealed that surface modification of the clay particles by HBP caused significant enhancement of the epoxy coating corrosion resistance especially when the ‘polymer/clay’ ratios were 10/1 and 5/1

  1. Synthesis of Polyurethane/Silica Modified Epoxy Polymer Based on 1,3-Propanediol for Coating Application

    Directory of Open Access Journals (Sweden)

    Lutviasari Nuraini

    2017-11-01

    Full Text Available Studies on the synthesis of polyurethane/silica modified epoxy polymer using 1,3-propanediol has been conducted. Synthesis of polymers made by reaction of tolonate and 1,3-propanediol (ratio NCO/OH=2.5 as the building blocks of polyurethane with diglycidyl ether bisphenol A (DGEBA epoxy and catalyst dibutyltin dilaurate (DBTL.The total weight of the polyurethane used was 20% (w/w of the total epoxy. Based on Fourier Transform Infrared (FTIR and 1H-Nuclear Magnetic Resonance (1H-NMR spectra indicated the existence of a new bond that is formed from the reaction of isocyanate group and hydroxyl group, where the hydroxyl groups derived from epoxy and 1,3-propanediol. The addition of silica (5, 10, and 15% w/w to epoxy into the epoxy-modified polyurethane has been carried out through sol-gel reaction of tetraethyl orthosilicate (TEOS. The isocyanate conversion rate for the addition of silica 5, 10, and 15% are 95.69; 100, and 100%, respectively. The morphology and element identification by Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX, showed that Si element has been successfully added in the polymer. From the tensile strength and elongation analysis, also thermal stability analysis using Thermal Gravimetric Analyzer (TGA, the increase of silica amount into the polyurethane modified epoxy did not significantly affect to thermal properties, but decrease the tensile strength of the polymer.

  2. Formulation of eb-curable epoxy resin : some important parameters

    International Nuclear Information System (INIS)

    Dahlan bin Haji Mohd; Hosoi, Fumio; Sasaki, Takashi

    1989-01-01

    The works on the electron-beam curing of surface coatings using epoxy acrylic-based resins were discussed. The works covered among other things the effect of molecular weights of the resins on the physical properties of coatings and their physical and chemical characterizations. The emphasis was given to formulating the resins applicable to surface coatings. Curings were done on a low-energy electron beam accelerator operating at 250 kV. A number of parameters deemed important to formulations, such as the molecular weights of the oligomers and monomers, monomer ratios, and HEA additions were explored. It was found that one could modify the physical properties of the coatings by changing or adjusting those parameters. (author)

  3. Volume Resistivity and Mechanical Behavior of Epoxy Nanocomposite Materials

    Directory of Open Access Journals (Sweden)

    M. F. Abdelkarim

    2015-04-01

    Full Text Available Electrical and mechanical properties of polymer composite materials are investigated through the determination of resistivity and hardness for composites samples. Epoxy composite samples have been prepared with different concentrations of certain inorganic fillers such as; Titanium dioxide (TiO2 and Silica (SiO2, of various size (micro, nano and hybrid to study the electrical and mechanical behavior. The volume resistivity reaches 3.23×1014 ohm.cm for the micro silica composite. Surface of composite material has been mechanically examined by hardness test. The results show that the resistivity of microcomposites and nanocmposites are increased with the decrease of filler concentration. But the resistivity of hybrid composites is increased with the increase of filler concentration. Maximum hardness value was obtained from hybrid silica composite with 0.1% filler concentration.

  4. Tritium sorption on protective coatings for concrete

    International Nuclear Information System (INIS)

    Miller, J.M.; Senohrabek, J.A.; Allsop, P.A.

    1992-11-01

    Because of the high sorption level of tritium on unprotected concrete, a program to examine the effectiveness of various concrete coatings and sealants in reducing tritium sorption was undertaken, and various exposure conditions were examined. Coatings of epoxy, polyurethane, bituminous sealant, bituminous sealant covered with polyvinylidene chloride wrap, alkyd paint, and sodium silicate were investigated with tritium (HTO) vapor concentration, humidity and contact time being varied. An exposure to HT was also carried out, and the effect of humidity on the tritium desorption rate was investigated. The relative effectiveness of the coatings was in the order of bituminous sealant + wrap > bituminous sealant > solvent-based epoxy > 100%-solids epoxy > alkyd paint > sodium silicate. The commercially available coatings for concrete resulted in tritium sorption being reduced to less than 7% of unprotected concrete. This was improved to ∼0.1% with the use of the Saran wrap (polyvinylidene chloride). The amount of tritium sorbed was proportional to tritium concentration. The total tritium sorbed decreased with an increase in humidity. A saturation effect was observed with increasing exposure time for both the coated and unprotected samples. Under the test conditions, complete saturation was not achieved within the maximum 8-hour contact time, except for the solvent-based epoxy. The desorption rate increased with a higher-humidity air purge stream. HT desorbed more rapidly than HTO, but the amount sorbed was smaller. The experimental program showed that HTO sorption by concrete can be significantly reduced with the proper choice of coating. However, tritium sorption on concrete and proposed coatings will continue to be a concern until the effects of the various conditions that affect the adsorption and desorption of tritium are firmly established for both chronic and acute tritium release conditions. Material sorption characteristics must also be considered in

  5. Permeability of protective coatings to tritium

    International Nuclear Information System (INIS)

    Braun, J.M.

    1987-10-01

    The permeability of four protective coatings to tritium gas and tritiated water was investigated. The coatings, including two epoxies, one vinyl and one urethane, were selected for their suitability in CANDU plant service in Ontario Hydro. Sorption rates of tritium gas into the coatings were considerably larger than for tritiated water, by as much as three to four orders of magnitude. However, as a result of the very large solubility of tritiated water in the coatings, the overall permeability to tritium gas and tritiated water are comparable, being somewhat larger for HTO. Marked differences were also evident among the four coatings, the vinyl proving to be unique in behaviour and morphology. Because of a highly porous surface structure water condensation takes place at high relative humidities, leading to an abnormally high retention of free water. Desorption rates from the four coatings were otherwise quite similar. Of practical importance was the observation that more effective desorption of tritiated water could be carried out at relatively high humidities, in this case 60%. It was believed that isotopic exchange was responsible for this phenomenon. It appears that epoxy coatings having a high pigment-to-binder ratio are most suited for coating concrete in tritium handling facilities

  6. Underwater Coatings for Contamination Control

    International Nuclear Information System (INIS)

    Julia L. Tripp; Kip Archibald; Ann-Marie Phillips; Joseph Campbell

    2004-01-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is deactivating several fuel storage basins. Airborne contamination is a concern when the sides of the basins are exposed and allowed to dry during water removal. One way of controlling this airborne contamination is to fix the contamination in place while the pool walls are still submerged. There are many underwater coatings available on the market that are used in marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives are easily applied and adhere well to the substrates (pool wall materials) found in INEEL fuel pools. The four pools considered included (1) Test Area North (TAN-607) with epoxy painted concrete walls; (2) Idaho Nuclear Technology and Engineering Center (INTEC) (CPP-603) with bare concrete walls; (3) Materials Test Reactor (MTR) Canal with stainless steel lined concrete walls; and (4) Power Burst Facility (PBF-620) with stainless steel lined concrete walls on the bottom and epoxy painted carbon steel lined walls on the upper portions. Therefore, the four materials chosen for testing included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The typical water temperature of the pools varies from 55 F to 80 F dependent on the pool and the season. These tests were done at room temperature. The following criteria were used during this evaluation. The underwater coating must: (1) Be easy to apply; (2) Adhere well to the four surfaces of interest; (3) Not change or have a negative impact on water chemistry or clarity; (4) Not be hazardous in final applied form; and (5) Be proven in other underwater applications. In addition, it is desirable for the coating to have a high pigment or high cross-link density to prevent radiation from penetrating. This paper will detail the testing completed and the test results. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates

  7. Synthesis, structure and properties of novel epoxy and rubber-modified epoxy impregnated Y-Ba-Cu-O superconductors

    International Nuclear Information System (INIS)

    Low, I.M.; Lim, F.W.; Chisholm, W.

    1992-01-01

    This paper reports the synthesis, structure and properties of novel YBa 2 Cu 3 O 6+x (123) - polymer composites. The polymers used were epoxy and rubber-modified epoxy resins. Superconducting composites with good strength, toughness, hardness and chemical resistance have been successfully fabricated. The presence of polymer(s) does not appear to affect the superconducting (T c ) of about 90 K. Levitation experiments show that the height (z) of the levitating magnet depends on sample thickness, and mass and pole strength of the magnet. A simple image force model best describes the observed dependence of z on the mass and pole strength. Atomic absorption and pH measurements in the corrosion study show that the polymer coating provides an impermeable barrier to the ingress of solvents and a concomitant resistance to phase decomposition. 12 refs., 2 tabs., 5 figs

  8. Thermal shock behavior of platinum aluminide bond coat/electron beam-physical vapor deposited thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhenhua, E-mail: zhxuciac@163.com [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Dai, Jianwei [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Niu, Jing [Shenyang Liming Aero-engine (Group) Corporation Ltd., Institute of Metallurgical Technology, Technical Center, Shengyang 110043 (China); Li, Na; Huang, Guanghong; He, Limin [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China)

    2014-12-25

    Highlights: • TBCs of (Ni, Pt)Al bond coat with grit blasting process and YSZ ceramic coating. • Grain boundary ridges are the sites for spallation damage initiation in TBCs. • Ridges removed, cavities formation appeared and the damage initiation deteriorated. • Damage initiation and progression at interface lead to a buckling failure. - Abstract: Thermal barrier coating systems (TBCs) including of chemical vapor deposited (Ni, Pt)Al bond coat with grit blasting process and electron beam physical vapor deposited Y{sub 2}O{sub 3}-stabilized-ZrO{sub 2} (YSZ) ceramic coating were investigated. The phase structures, surface and cross-sectional morphologies, thermal shock behaviors and residual stresses of the coatings were studied in detail. Grain boundary ridges still remain on the surface of bond coat prior to the deposition of the ceramic coating, which are shown to be the major sites for spallation damage initiation in TBCs. When these ridges are mostly removed, they appear some of cavities formation and then the damage initiation mode is deteriorated. Damage initiation and progression occurs at the bond coat to thermally grown oxide (TGO) interface leading to a buckling failure behavior. A buckle failure once started may be arrested when it runs into a region of high bond coat to TGO interface toughness. Thus, complete failure requires further loss in toughness of the bond coat to TGO interface during cooling. The suppressed cavities formation, the removed ridges at the grain boundaries, the relative high TGO to bond coat interface toughness, the uniform growth behavior of TGO thickening and the lower of the residual stress are the primary factors for prolonging the lifetime of TBCs.

  9. Degradation of epoxy coatings under gamma irradiation

    International Nuclear Information System (INIS)

    Djouani, F.; Zahra, Y.; Fayolle, B.; Kuntz, M.; Verdu, J.

    2013-01-01

    Epoxy networks based on Diglycidyl ether of bisphenol A (DGEBA) and cured with Jeffamine® (POPA) or polyamidoamine (PAA) were gamma irradiated at 25 °C in air. Dose rates of 50, 200 or 2000 Gy h −1 for doses up 100 kGy were used. Structural changes were monitored by IR spectrophotometry, DSC and sol–gel analysis. Both networks display some common features: for I≥200 Gy h −1 , reaction products grow proportionally to time and the rate is a decreasing function of dose rate. The simplest explanation is that peroxy radicals are the main precursors of these products (in the dose rate domain under study), through a unimolecular rearrangement of which an hypothetical mechanism is proposed. DGEBA–POPA are more reactive then DGEBA–PAA networks (according to IR criteria), that can be attributed to the high reactivity of tertiary CH bands in polyoxypropylene segments. The oxidation of these sites leads to methyl ketones. A simple kinetic model in which methyl ketones result from rearrangements of tertiary peroxyls and from tertiary alkoxyls was proposed. It leads to an expression of the radiochemical yield of methyl ketones (G(MK)) of the form G(MK)=a+bI −1/2 where a and b are parameters depending of elementary rate constants. Experimental G(MK) values are reasonably well fitted by this equation. In DGEBA–PAA networks, a wide variety of oxidation products, among which amides predominate, can be observed. In these networks, chain scissions predominate over crosslinking, whereas a slight predominance of crosslinking was observed, at least for the lowest dose rate, in DGEBA–POPA. - Highlights: ► The effects of irradiation at three distinct dose rates have been studied on two epoxy networks. ► DGEBA–polyamidoamine networks appear more stable than DGEBA–polyoxypropylene diamine ones. ► A simple kinetic model involving methyl ketones is proposed.

  10. The effects of carbon nanotubes on electroactive shape-memory behaviors of hydro-epoxy/carbon black composite

    International Nuclear Information System (INIS)

    Wei, Kun; Zhu, Guangming; Tang, Yusheng; Liu, Tingting; Li, Ximin

    2012-01-01

    The objective of this work is to characterize the effect of multi-walled carbon nanotubes (MWCNTs) on the thermomechanical, electrical and shape-memory properties of hydro-epoxy/carbon black (CB) composite. The shape-memory hydro-epoxy composite is fabricated by adding MWCNTs and CB into shape-memory hydro-epoxy resin. The total amount of the fillers fixed at 1.9 wt%, five different composites are produced by varying the amount of MWCNTs between 0 and 0.8 wt% and the amount of CB between 1.1 and 1.9 wt%. The thermomechanical properties and shape-memory performance of the composites are studied. These results indicate that the glass transition temperature (Tg) and the storage modulus of the composites increases at first and then decreases as MWCNTs content increases. The shape recovery time decreases at first and then increases slightly as MWCNTs content increases. The composite presents good shape-memory behavior, and the shape recovery ratio is around 100%. Due to the synergic effect of CB and MWCNTs, the volume electrical resistivity of the composite could decrease by adding a small amount of MWCNTs. (paper)

  11. Study on epoxy/BaTiO3 composite embedded capacitor films (ECFs) for organic substrate applications

    International Nuclear Information System (INIS)

    Cho, Sung-Dong; Lee, Joo-Yeon; Hyun, Jin-Gul; Paik, Kyung-Wook

    2004-01-01

    Embedded capacitor films (ECFs) were newly designed for high dielectric constant and low capacitance tolerance (less than ±5%) embedded capacitor fabrication for organic substrates. ECFs are transferable and B-stage films which can be coated on a releasing film. In terms of materials formulation, ECFs are composed of high dielectric constant BaTiO 3 (BT) powder, specially formulated epoxy resin, and latent curing agent. And in terms of coating process, a roll coating method is used for obtaining film thickness uniformity in a large area. Differential scanning calorimeter (DSC) thermal analysis was conducted to determine the optimum amount of curing agent, curing temperature, and curing time. Changes in the dielectric constant of epoxy/BaTiO 3 composite ECFs with BT particle sizes and contents were investigated. Dielectric constant of 90 was obtained using two different size BaTiO 3 powders mixture. Typically, capacitors of 12 μm thick film with 8 nF/cm 2 with less than ±5% capacitance tolerance and low leakage current (less than 10 -7 A/cm 2 at 10 V) were successfully demonstrated on PCBs using epoxy/BaTiO 3 composite embedded capacitor films

  12. BEHAVIOR OF THERMAL SPRAY COATINGS AGAINST HYDROGEN ATTACK

    OpenAIRE

    Vargas, Fabio; Latorre, Guillermo; Uribe, Iván

    2003-01-01

    The behavior of nickel and chrome alloys applied as thermal spray coatings to be used as protection against embrittlement by hydrogen is studied. Coatings were applied on a carbon steel substrate, under conditions that allow obtain different crystalline structures and porosity levels, in order to determine the effect of these variables on the hydrogen permeation kinetics and as a protection means against embrittlement caused this element. In order to establish behaviors as barriers and protec...

  13. ETV Program Report: Coatings for Wastewater Collection ...

    Science.gov (United States)

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Material and Technology (CIGMAT) Laboratory at the University of Houston. Testing was conducted over a period of six months to evaluate the coating’s (1) chemical resistance and (2) bonding strength for infrastructure applications. For chemical resistance, coated concrete and clay bricks with holidays (holes created in the coating) were used to evaluate the chemical resistance of the coating/substrate bond under a corrosive environment. Twenty coated concrete (dry and wet) and 20 coated clay brick (dry and wet) specimens were exposed to DI water and sulfuric acid solution (pH=1), and the specimens were visually inspected and weight changes measured. Evaluation of the coating-to-substrate bonding strength was determined using two modified ASTM test methods – one to determine bond strength of the coating with two specimens sandwiched together using the coating, and the second to determine the bond strength by applying a tensile load to the coating applied to specimens of each substrate. Forty-eight bonding tests were performed over the six month evaluation. The tests resulted in the following conclusions about Standard Cement’s SEC 4553 coating: • After the six-month chemi

  14. Comparison of anti-corrosion properties of polyurethane based composite coatings with low infrared emissivity

    International Nuclear Information System (INIS)

    Wang Yajun; Xu Guoyue; Yu Huijuan; Hu Chen; Yan Xiaoxing; Guo Tengchao; Li Jiufen

    2011-01-01

    Four polyurethane resins, pure polyurethane (PU), epoxy modified polyurethane (EPU), fluorinated polyurethane (FPU) and epoxy modified fluorinated polyurethane (EFPU), with similar polyurethane backbone structure but different grafting group were used as organic adhesive for preparing low infrared emissivity coatings with an extremely low emissivity near 0.10 at 8-14 μm, respectively. By using these four resins, the effect of different resin matrics on the corrosion protection of the low infrared emissivity coatings was investigated in detail by using neutral salt spray test, SEM and FTIR. It was found that the emissivity of the coatings with different resin matrics changes significantly in corrosion media. And the results indicated that the coating using EFPU as organic adhesive exhibited excellent corrosion resistance property which was mainly attributed to the presence of epoxy group and atomic fluorine in binder simultaneously.

  15. Oxidation behavior of Ru–Al multilayer coatings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Zheng, Zhi-Ting; Kai, Wu; Huang, Yu-Ren

    2017-06-01

    Highlights: • Ru{sub 0.63}Al{sub 0.37} multilayer coatings were fabricated using cosputtering. • Oxidation behavior of Ru{sub 0.63}Al{sub 0.37} coatings in 1% O{sub 2}–99% Ar was studied. • Internal oxidation of Ru{sub 0.63}Al{sub 0.37} coatings at 400–600 °C was multi stage parabolic. • External oxidation of Ru{sub 0.63}Al{sub 0.37} was conducted after annealing at 700–800 °C. - Abstract: Ru{sub 0.63}Al{sub 0.37} coatings were deposited through a cyclical gradient concentration deposition at 400 °C with a substrate-holder rotation speed of 1 rpm by direct current magnetron cosputtering. Scanning electron microscopy revealed that the as-deposited coatings exhibited a multilayer structure along with the columnar structure. The oxidation behavior of the Ru{sub 0.63}Al{sub 0.37} coatings was examined through X-ray diffraction, Auger electron spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Oxidation kinetics was measured using a thermogravimetric analyzer. Internal oxidation was observed for Ru{sub 0.63}Al{sub 0.37} coatings annealed in a 1% O{sub 2}–99% Ar atmosphere at 400–600 °C accompanied with activation energies of 72–84 kJ/mol. By contrast, external oxidation was observed after annealing at 700–800 °C, resulting in the formation of a continuous alumina scale consisting of crystalline δ-Al{sub 2}O{sub 3} domains, which can be attributable to the outward diffusion of Al.

  16. Design and characterization of non-toxic nano-hybrid coatings for corrosion and fouling resistance

    Directory of Open Access Journals (Sweden)

    P. Saravanan

    2016-09-01

    Full Text Available Epoxy resin modified with nano scale fillers offers excellent combination of properties such as enhanced dimensional stability, mechanical and electrical properties, which make them ideally suitable for a wide range of applications. However, the studies about functionalized nano-hybrid for coating applications still require better insight. In the present work we have developed silane treated nanoparticles and to reinforce it with diglycidyl epoxy resin to fabricate surface functionalized nano-hybrid epoxy coatings. The effect of inorganic nano particles on the corrosion and fouling resistance properties was studied by various (1, 3, 5 and 7 wt% filler loading concentrations. Diglycidyl epoxy resin (DGEBA commonly was used for coating. 3-Aminopropyltriethoxysilane (APTES was used as a coupling agent to surface treats the TiO2 nanoparticles. The corrosion and fouling resistant properties of these coatings were evaluated by electrochemical impedance and static immersion tests, respectively. Nano-hybrid coating (3 wt% of APTES–TiO2 showed corrosion resistance up to 108 Ω cm2 after 30 days immersion in 3.5% NaCl solution indicating an excellent corrosion resistance. Static immersion test was carried out in Bay of Bengal (Muttukadu which has reflected good antifouling efficiency of the 3 wt% APTES–TiO2 loaded nano-hybrid coating up to 6 months.

  17. Studies on Fracture Behavior of Epoxy/DWNT Nanocomposites by Molecular Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    Shahin Shadlou

    2012-12-01

    Full Text Available The nanoscale fracture behavior of epoxy-based nanocomposites reinforced with double-walled carbon nanotube (DWNT was investigated by molecular dynamics (MD simulations technique. In order to prepare a nanocomposite model including polymer and DWNT, the exact atomic structure of epoxy was adopted as in previous experimental studies made by authors. Tersoff and Amber potential, which are well known potentials, were used for simulation of polymer and DWNT, respectively. Among different available methods to simulate the cross-linking process, a technique was adopted with closer similarity to what happens in real conditions. Therefore, when some especial atoms of monomer and hardener molecules were closer than a specific potential distance, the chemical bonds were created between them. To verify the prepared model, a pull-out simulation was carried out and the results were compared with those of previous studies. It was found that although a rather wide range for interface strength has been presented by different researchers and different techniques, the strength obtained in this study is in the middle of this range. In addition, the fracture energy obtained from the simulations for pure epoxy was compared with that of experimental results and good agreement was obtained. To evaluate the effect of nanocomposite structure at nanometer scale, DWNT was modeled in three different angles relative to the loading direction, including 0°, 45°and 90°. It was found that when DWNT is parallel with the loading direction (i.e. 90° it has the least impact on the fracture energy. The maximum fracture energy was obtained when MWNT was at 45° relative to loading direction. These results were compared with the theories provided for conventional composites.

  18. Microstructure and strain rate effects on the mechanical behavior of particle reinforced epoxy-based reactive materials

    Science.gov (United States)

    White, Bradley William

    The effects of reactive metal particles on the microstructure and mechanical properties of epoxy-based composites is investigated in this work. Particle reinforced polymer composites show promise as structural energetic materials that can provide structural strength while simultaneously being capable of releasing large amounts of chemical energy through highly exothermic reactions occurring between the particles and with the matrix. This advanced class of materials is advantageous due to the decreased amount of high density inert casings needed for typical energetic materials and for their ability to increase payload expectancy and decrease collateral damage. Structural energetic materials can be comprised of reactive particles that undergo thermite or intermetallic reactions. In this work nickel (Ni) and aluminum (Al) particles were chosen as reinforcing constituents due to their well characterized mechanical and energetic properties. Although, the reactivity of nickel and aluminum is well characterized, the effects of their particle size, volume fractions, and spatial distribution on the mechanical behavior of the epoxy matrix and composite, across a large range of strain rates, are not well understood. To examine these effects castings of epoxy reinforced with 20--40 vol.% Al and 0--10 vol.% Ni were prepared, while varying the aluminum nominal particle size from 5 to 50 mum and holding the nickel nominal particle size constant at 50 mum. Through these variations eight composite materials were produced, possessing unique microstructures exhibiting different particle spatial distributions and constituent makeup. In order to correlate the microstructure to the constitutive response of the composites, techniques such as nearest-neighbor distances, and multiscale analysis of area fractions (MSAAF) were used to quantitatively characterize the microstructures. The composites were investigated under quasi-static and dynamic compressive loading conditions to characterize

  19. Improved Metallography Of Thermal-Barrier Coatings

    Science.gov (United States)

    Brindley, William J.; Leonhardt, Todd A.

    1991-01-01

    New technique for preparation of metallographic samples makes interpretation of images of pores and microcracks more reliable. Involves use of vacuum epoxy infiltration and interference-film coating to reduce uncertainty. Developed for inspection of plasma-sprayed ceramic thermal-barrier coatings on metals but applicable to other porous, translucent materials, including many important ceramics.

  20. Corrosion behavior of ceramic-coated ZIRLO™ exposed to supercritical water

    Science.gov (United States)

    Mandapaka, Kiran K.; Cahyadi, Rico S.; Yalisove, Steven; Kuang, Wenjun; Sickafus, K.; Patel, Maulik K.; Was, Gary S.

    2018-01-01

    The corrosion behavior of ceramic coated ZIRLO™ tubing was evaluated in a supercritical water (SCW) environment to determine its behavior in high temperature water. Two coating architectures were analyzed; a 4 bi-layer TiAlN/TiN coating with Ti bond coat, and a TiN monolithic coating with Ti bond layer on ZIRLO™ tubes using cathodic arc physical vapor deposition (CA-PVD) technique. Femtosecond laser ablation was used to introduce reproducible defects in some of the coated tubes. On exposure to deaerated supercritical water at 542 °C for 48 h, coated tubes exhibited significantly higher weight gain compared to uncoated ZIRLO™. Examination revealed formation of a uniform ZrO2 layer beneath the coating of a thickness similar to that on the uncoated tube inner surface. The defects generated during the coating process acted as preferential paths for diffusion of oxygen resulting in the oxidation of substrate ZIRLO™. However, there was no delamination of the coating. There were insignificant differences in the oxidation weight gain between laser ablated and non-ablated tubes and the laser induced defects did not spread beyond their original size.

  1. Curing kinetics, mechanism and chemorheological behavior of methanol etherified amino/novolac epoxy systems

    Directory of Open Access Journals (Sweden)

    S. F. Zhao

    2014-02-01

    Full Text Available The curing kinetics and mechanism of epoxy novolac resin (DEN and modified epoxy novolac resin (MDEN with methanol etherified amino resin were studied by means of differential scanning calorimetry (DSC, Fourier transforminfrared (FT-IR spectroscopy and chemorheological analysis. Their kinetics parameters and models of the curing were examined utilizing isoconversional methods, Flynn-Wall-Ozawa and Friedman methods. For the DEN mixture, its average activation energy (Ea was 71.05 kJ/mol and the autocatalytic model was established to describe the curing reaction. The MDEN mixture exhibited three dominant curing processes, termed as reaction 1, reaction 2 and reaction 3; and their Ea were 70.05, 106.55 and 101.91 kJ/mol, respectively. Besides, Ea of reaction 1 was similar to that of DEN mixture, while Ea of reactions 2 and 3 corresponded to that of the etherification reaction between hydroxyl and epoxide group. Moreover, these three dominant reactions were nth order in nature. Furthermore, their curing mechanisms were proposed from the results of DSC and FTIR. The chemorheological behavior was also investigated to obtain better plastics products via optimizing the processing schedules.

  2. Adhesive strength of hydroxyl apatite(HA) coating and biomechanics behavior of HA-coated prosthesis:an experimental study

    OpenAIRE

    Tian-yang ZHANG; Yong-hong DUAN; Shu ZHU; Jin-yu ZHU; Qing-sheng ZHU

    2011-01-01

    Objective To explore the influence of adhesive strength of hydroxyapatite(HA) coating on the post-implantation stability of HA-coated prosthesis.Methods The adhesive strength and biomechanics behavior of HA coating were studied by histopathological observation,material parameters and biomechanical testing,the titanium(Ti)-coated prosthesis was employed as control.Results Scratch test showed that the adhesive strength of HA coating was significantly lower than that of Ti coating(P < 0.01).Hist...

  3. Fabrication and mechanical properties of multi-walled carbon nanotubes/epoxy nanocomposites

    International Nuclear Information System (INIS)

    Yeh, M.-K.; Hsieh, T.-H.; Tai, N.-H.

    2008-01-01

    Carbon nanotubes have better physical and mechanical behavior than the traditional materials. In this study, the multi-walled carbon nanotubes (MWNTs) were added to the epoxy resin as a reinforcement to fabricate MWNTs/epoxy nanocomposites. The pressure and temperature were applied to cure the MWNTs/epoxy compound by hot press method. Mechanical properties such as tensile strength, Young's modulus, and Poisson's ratio were measured. The effect of weight percentages of the MWNTs was investigated. Morphologies of the fracture surface of MWNTs/epoxy nanocomposites were observed by scanning electron microscope

  4. Studies on Mathematical Models of Wet Adhesion and Lifetime Prediction of Organic Coating/Steel by Grey System Theory.

    Science.gov (United States)

    Meng, Fandi; Liu, Ying; Liu, Li; Li, Ying; Wang, Fuhui

    2017-06-28

    A rapid degradation of wet adhesion is the key factor controlling coating lifetime, for the organic coatings under marine hydrostatic pressure. The mathematical models of wet adhesion have been studied by Grey System Theory (GST). Grey models (GM) (1, 1) of epoxy varnish (EV) coating/steel and epoxy glass flake (EGF) coating/steel have been established, and a lifetime prediction formula has been proposed on the basis of these models. The precision assessments indicate that the established models are accurate, and the prediction formula is capable of making precise lifetime forecasting of the coatings.

  5. Study on drilling induced delamination of woven kenaf fiber reinforced epoxy composite using carbide drills

    Science.gov (United States)

    Suhaily, M.; Hassan, C. H. Che; Jaharah, A. G.; Azmi, H.; Afifah, M. A.; Khairusshima, M. K. Nor

    2018-04-01

    In this research study, it presents the influences of drilling parameters on the delamination factor during the drilling of woven kenaf fiber reinforced epoxy composite laminates when using the carbide drill bits. The purpose of this study is to investigate the influence of drilling parameters such as cutting speed, feed rate and drill sizes on the delamination produced when drilling woven kenaf reinforced epoxy composite using the non-coated carbide drill bits. The damage generated on the woven kenaf reinforced epoxy composite laminates were observed both at the entrance and exit surface during the drilling operation. The experiments were conducted according to the Box Behnken experimental designs. The results indicated that the drill diameter has a significant influence on the delamination when drilling the woven kenaf fiber reinforced epoxy composites.

  6. Epoxy cracking in the epoxy-impregnated superconducting winding: nonuniform dissipation of stress energy in a wire-epoxy matrix model

    International Nuclear Information System (INIS)

    Tsukamoto, O.; Iwasa, Y.

    1985-01-01

    The authors present the epoxy-crack-induced temperature data of copper wires imbedded in wire-epoxy resin composite model at 4.2 K. The experimental results show that the epoxy-crackinduced temperature rise is higher in the copper wires than in the epoxy matrix, indicating that in stress-induced wire-epoxy failure, stress energy stored in the wire-epoxy matrix is preferrentially dissipated in the wire. A plausible mechanism of the nonuniform dissipation is presented

  7. Fusion bonded epoxy mainline and field joint coatings performance from the X100 field trial - A case study

    Energy Technology Data Exchange (ETDEWEB)

    Jadoon, A.N.K., E-mail: ammer.jadoon@bp.com [BP Exploration and Production Technology, Chertsey Road, Sunbury TW16-7LN (United Kingdom); Thompson, I. [GL Industrial Services UK, Holywell Park, Loughborough LE11-3GR (United Kingdom)

    2012-04-15

    Operating and distribution companies are potentially interested in the use of high and ultra-high strength steels for the transportation of high pressure gas. The ultra-high strength X100 grade steel was commercially developed as a potential option to meet this. However, there has been limited industry wide use of X100 to date. BP carried out a 2 year field trial to demonstrate the operational capacity and integrity of a large diameter (48 inch/1219 mm) high pressure pipeline constructed from X100 grade steel. The 800 m pipeline was buried in a clay backfill and exposed to wet ground conditions associated with the North of England. Flow pressure cycling was carried out, using water, to simulate 40 years of operational service. A 200 m section of the pipeline was exposed to three different potential (cathodic protection) zones for the duration of the trial: zero potential, intermediate potential (-850 to -950 mV) and high potential (-1200 to -1300 mV). This section also had damage and defects induced which are typically associated with bad installation and commissioning. An area of potential concern is the degradation of the mechanical properties (strain ageing) due to the external coating application temperature. Thus, a low coating application temperature is deemed desirable. The mainline and field joint coatings employed for the trial were fusion bonded epoxy (FBE). Both of these have been used in other BP projects, with a good track record. They were applied at a lower application temperature of 220 Degree-Sign C, compared to the more typical 230-240 Degree-Sign C. The lower application temperature was within the manufacturers approved application and curing temperature range. The lower temperature was used to assess the ultimate performance properties of the mainline and field joint FBE coatings. Mainline and field joint coating samples were taken from the three different potential zones and extensive testing and characterisation carried out. This paper

  8. Reduction of cathodic delamination rates of anticorrosive coatings using free radical scavengers

    DEFF Research Database (Denmark)

    Sørensen, Per Aggerholm; Weinell, C. E.; Dam-Johansen, Kim

    2010-01-01

    Cathodic delamination is one of the major modes of failure for anticorrosive coatings subjected to a physical damage and immersed in seawater. The cause of cathodic delamination has been reported to be the result of a chemical attack at the coating-steel interface by free radicals and peroxides...... formed as intermediates in the cathodic reaction during the corrosion process. In this study, antioxidants (i.e., free radical scavengers and peroxide decomposers) have been incorporated into various generic types of coatings to investigate the effect of antioxidants on the rate of cathodic delamination...... of epoxy coatings on cold rolled steel. The addition of free radical scavengers to epoxy coatings improved the resistance toward cathodic delamination by up to 50% during seawater immersion, while peroxide decomposers had a limited effect. Testing using substrates prepared from stainless steel...

  9. Preparation and optical properties of indium tin oxide/epoxy nanocomposites with polyglycidyl methacrylate grafted nanoparticles.

    Science.gov (United States)

    Tao, Peng; Viswanath, Anand; Schadler, Linda S; Benicewicz, Brian C; Siegel, Richard W

    2011-09-01

    Visibly highly transparent indium tin oxide (ITO)/epoxy nanocomposites were prepared by dispersing polyglycidyl methacrylate (PGMA) grafted ITO nanoparticles into a commercial epoxy resin. The oleic acid stabilized, highly crystalline, and near monodisperse ITO nanoparticles were synthesized via a nonaqueous synthetic route with multigram batch quantities. An azido-phosphate ligand was synthesized and used to exchange with oleic acid on the ITO surface. The azide terminal group allows for the grafting of epoxy resin compatible PGMA polymer chains via Cu(I) catalyzed alkyne-azide "click" chemistry. Transmission electron microscopy (TEM) observation shows that PGMA grafted ITO particles were homogeneously dispersed within the epoxy matrix. Optical properties of ITO/epoxy nanocomposites with different ITO concentrations were studied with an ultraviolet-visible-near-infrared (UV-vis-NIR) spectrometer. All the ITO/epoxy nanocomposites show more than 90% optical transparency in the visible light range and absorption of UV light from 300 to 400 nm. In the near-infrared region, ITO/epoxy nanocomposites demonstrate low transmittance and the infrared (IR) transmission cutoff wavelength of the composites shifts toward the lower wavelength with increased ITO concentration. The ITO/epoxy nanocomposites were applied onto both glass and plastic substrates as visibly transparent and UV/IR opaque optical coatings.

  10. Studies of decontamination using easy removable coatings technique

    International Nuclear Information System (INIS)

    Oglaza, J.; Nowak, Z.

    1991-01-01

    The usefulness of removable coatings for decontamination of steel and epoxy-resin painted surfaces was examined. Natural latex, Revultex, butadiene-styrene latex as well as mixtures of latex with complexing agents and surfactants were used as decontaminating coats. The best decontamination was obtained by removable coatings of natural latex with EDTA additive for all surfaces and radionuclides tested. (author). 16 refs, 5 tabs

  11. Corrosion-Protection Coatings for Aluminum

    Science.gov (United States)

    Higgins, R. H.

    1983-01-01

    Study investigates 21 combinatios of surface treatments, primers and topcoats. Study considers several types of coatings, including primers, enamels, chlorinated rubbers, alkyds, epoxies, vinyls, polyurethanes, waterbased paints, and antifouling paints. 20-page report summarizes the study.

  12. Fracture behaviour of a self-healing microcapsule-loaded epoxy system

    Directory of Open Access Journals (Sweden)

    2011-03-01

    Full Text Available The effect of temperature on the fracture behaviour of a microcapsule-loaded epoxy matrix was investigated. Microencapsulated epoxy and mercaptan-derivative healing agents were incorporated into an epoxy matrix to produce a polymer composite capable of self-healing. Maximum fracture loads were measured using the double-torsion method. Thermal aging at 55 and 110°C for 17 hours [hrs] was applied to heal the pre-cracked samples. The addition of microcapsules appeared to increase significantly the load carrying capacity of the epoxy after healing. Once healed, the composites achieved as much as 93–171% of its virgin maximum fracture load at 18, 55 and 110°C. The fracture behavior of the microcapsule- loaded epoxy matrix was influenced by the healing temperature. The high self-healing efficiency may be attributed to the result of the subsurface micro-crack pinning or deviation, and to a stronger microencapsulated epoxy and mercaptanderivative binder than that of the bulk epoxy. The results show that the healing temperature has a significant effect on recovery of load transferring capability after fracture.

  13. Gold Nanospheres Dispersed Light Responsive Epoxy Vitrimers

    Directory of Open Access Journals (Sweden)

    Zhenhua Wang

    2018-01-01

    Full Text Available Vitrimers represent a new class of smart materials. They are covalently crosslinked like thermosets, yet they can be reprocessed like thermoplastics. The underlying mechanism is the rapid exchange reactions which form new bonds while breaking the old ones. So far, heating is the most widely used stimulus to activate the exchange reaction. Compared to heating, light not only is much more convenient to achieve remote and regional control, but can also offer fast healing. Gold nanospheres are excellent photothermal agents, but they are difficult to disperse into vitrimers as they easily aggregate. In this paper, we use polydopamine to prepare gold nanospheres. The resultant polydopamine-coated gold nanospheres (GNS can be well dispersed into epoxy vitrimers, endowing epoxy vitrimers with light responsivity. The composites can be reshaped permanently and temporarily with light at different intensity. Efficient surface patterning and healing are also demonstrated.

  14. Prediction of energy absorption characteristics of aligned carbon nanotube/epoxy nanocomposites

    International Nuclear Information System (INIS)

    Weidt, D; Figiel, Ł; Buggy, M

    2012-01-01

    This research aims ultimately at improving the impact performance of laminates by applying a coating of epoxy containing carbon nanotubes (CNTs). Here, 2D and 3D computational modelling was carried out to predict energy absorption characteristics of aligned CNT/epoxy nanocomposites subjected to macroscopic compression under different strain rates (quasi-static and impact rates). The influence of the rate-dependent matrix behaviour, CNT aspect ratio and CNT volume fraction on the energy absorption characteristics of the nanocomposites was evaluated. A strong correlation between those parameters was found, which provides an insight into a rate-dependent behaviour of the nanocomposites, and can help to tune their energy absorption characteristics.

  15. Effect of coating thickness on interfacial shear behavior of zirconia-coated sapphire fibers in a polycrystalline alumina matrix

    International Nuclear Information System (INIS)

    Hellmann, J.R.; Chou, Y.S.

    1995-01-01

    The effect of zirconia (ZrO 2 ) interfacial coatings on the interfacial shear behavior in sapphire reinforced alumina was examined in this study. Zirconia coatings of thicknesses ranging from 0.15 to 1.45 μm were applied to single crystal sapphire (Saphikon) fibers using a particulate loaded sol dipping technique. After calcining at 1,100 C in air, the coated fibers were incorporated into a polycrystalline alumina matrix via hot pressing. Interfacial shear strength and sliding behavior of the coated fibers was examined using thin-slice indentation fiber pushout and pushback techniques. In all cases, debonding and sliding occurred at the interface between the fibers and the coating. The coatings exhibited a dense microstructure and led to a higher interfacial shear strength (> 240 MPa) and interfacial sliding stress (> 75 MPa) relative to previous studies on the effect of a porous interphase on interfacial properties. The interfacial shear strength decreased with increasing fiber coating thickness (from 389 ± 59 to 241 ± 43 MPa for 0.15 to 1.45 microm thick coatings, respectively). Sliding behavior exhibited load modulation with increasing displacement during fiber sliding which is characteristic of fiber roughness-induced stick-slip. The high interfacial shear strengths and sliding stresses measured in this study, as well as the potentially strength degrading surface reconstruction observed on the coated fibers after hot pressing and heat treatment, indicate that dense zirconia coatings are not suitable candidates for optimizing composite toughness and strength in the sapphire fiber reinforced alumina system

  16. Manufacturing of REBCO coils strongly bonded to cooling members with epoxy resin aimed at its application to Maglev

    Science.gov (United States)

    Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi

    2014-11-01

    The REBCO coated conductor has been attracted attention because of its high current density in the presence of high magnetic field. If the coated conductor is applied to Maglev, the operational temperature of the on-board magnets will be over 40 K and energy consumption of cryocoolers will be reduced. That high operational temperature also means the absence of liquid helium. Therefore, reliable thermal coupling is desirable for cooling the coils. We propose an epoxy impregnated REBCO coil co-wound with PTFE tape. While the PTFE tape prevents the performance degradation of the coil, the epoxy resin bonds the coil to cooling members. We carried out three experiments to confirm that the coil structure which we propose has robust thermal coupling without the degradation. First, thermal resistances of paraffin and epoxy were measured varying the temperature from room temperature to 10 K. The measurement result indicates that paraffin has a risk of losing thermal coupling during cooling down. In another experiment, PTFE (polytetrafluoroethylene) tape insulator prevented performance degradation of a small epoxy impregnated REBCO coil, while another REBCO coil with polyimide tape showed clear performance degradation. Finally, we produced a racetrack REBCO coil with the same outer dimension as a Maglev on-board magnet coil. Although the racetrack coil was installed in a GFRP coil case and tightly bonded to the case by epoxy impregnation, any performance degradation was not observed.

  17. Organo-Aluminate Polymeric Materials as Advanced Erosion/Corrosion Resistant Thin Film Coatings

    National Research Council Canada - National Science Library

    Cook, Ronald

    1997-01-01

    ...) and hazardous air pollutants (HAPs). The coating system is based on the development of carboxylato- alumoxane precursors for fabrication of corrosion resistant oxide barrier layers and alumoxane-epoxy based primer coats...

  18. Influence of Silane modified nano silica on the corrosion protection of zinc rich coating

    International Nuclear Information System (INIS)

    Nguyen Thuy Duong; To Thi Xuan Hang; Trinh Anh Truc; Pham Gia Vu; Bui Van Truoc; Thai Hoang

    2015-01-01

    Zinc rich coatings are the best effective primers for corrosion protection of carbon steel in aggressive conditions. For traditional zinc rich primer the zinc content is very high, more than 90 wt.%. The coating adhesion is decreased with the increase of zinc content, so that it is necessary to decrease the zinc content by using additives. In this study the nano silica modified by N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane was prepared and incorporated in zinc rich epoxy coatings containing 85 wt.% zinc powder. The corrosion protection performance of coatings was evaluated by electrochemical impedance spectroscopy. The results obtained show that the presence of nano silica improved corrosion protection of zinc rich epoxy coating and the best protection was obtained with 3 wt.% nano silica. (author)

  19. Curing behaviors and properties of an extrinsic toughened epoxy/anhydride system and an intrinsic toughened epoxy/anhydride system

    International Nuclear Information System (INIS)

    Fan, Mengjin; Liu, Jialin; Li, Xiangyuan; Cheng, Jue; Zhang, Junying

    2013-01-01

    Highlights: ► Two curing systems (ETRS and ITRS) with similar chemical composite were prepared. ► The curing kinetics of the ETRS and the novel ITRS were comparatively studied. ► Crosslinking density can affect the kinetic schemes of the two curing systems. ► Their mechanical properties and thermal stabilities were also comparatively studied. ► Crosslinking density may play an influential role in mechanical properties. - Abstract: The curing kinetics of an extrinsic toughened epoxy (mixture of diglycidyl ether of bisphenol-A and 1,4-butanediol epoxy resin, DGEBA/DGEBD) and an intrinsic toughened epoxy (ethoxylated bisphenol-A epoxy resin with two oxyethylene units, DGEBAEO-2) using hexahydrophthalic anhydride (HHPA) as curing agent and tris-(dimethylaminomethyl) phenol (DMP-30) as accelerator were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TGA, respectively. The results showed that Šesták–Berggren model can generally simulate well the reaction rates of these two systems. The activation energy of DGEBA/DGEBD/HHPA/DMP-30 at high fractional conversion changed much higher than that of DGEBAEO-2/HHPA/DMP-30, indicating the increased steric hindrance mainly affected the reaction kinetic scheme of DGEBA/DGEBD/HHPA/DMP-30. The T g and storage moduli of cured DGEBAEO-2/HHPA/DMP-30 were lower than those of cured DGEBA/DGEBD/HHPA/DMP-30 according to DMTA while TGA showed that the thermal stabilities of these two cured systems were similar

  20. Curing behaviors and properties of an extrinsic toughened epoxy/anhydride system and an intrinsic toughened epoxy/anhydride system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Mengjin; Liu, Jialin; Li, Xiangyuan [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Cheng, Jue, E-mail: chengjue@mail.buct.edu.cn [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Junying, E-mail: zjybuct@gmail.com [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)

    2013-02-20

    Highlights: ► Two curing systems (ETRS and ITRS) with similar chemical composite were prepared. ► The curing kinetics of the ETRS and the novel ITRS were comparatively studied. ► Crosslinking density can affect the kinetic schemes of the two curing systems. ► Their mechanical properties and thermal stabilities were also comparatively studied. ► Crosslinking density may play an influential role in mechanical properties. - Abstract: The curing kinetics of an extrinsic toughened epoxy (mixture of diglycidyl ether of bisphenol-A and 1,4-butanediol epoxy resin, DGEBA/DGEBD) and an intrinsic toughened epoxy (ethoxylated bisphenol-A epoxy resin with two oxyethylene units, DGEBAEO-2) using hexahydrophthalic anhydride (HHPA) as curing agent and tris-(dimethylaminomethyl) phenol (DMP-30) as accelerator were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TGA, respectively. The results showed that Šesták–Berggren model can generally simulate well the reaction rates of these two systems. The activation energy of DGEBA/DGEBD/HHPA/DMP-30 at high fractional conversion changed much higher than that of DGEBAEO-2/HHPA/DMP-30, indicating the increased steric hindrance mainly affected the reaction kinetic scheme of DGEBA/DGEBD/HHPA/DMP-30. The T{sub g} and storage moduli of cured DGEBAEO-2/HHPA/DMP-30 were lower than those of cured DGEBA/DGEBD/HHPA/DMP-30 according to DMTA while TGA showed that the thermal stabilities of these two cured systems were similar.

  1. Laser-based coatings removal

    International Nuclear Information System (INIS)

    Freiwald, J.G.; Freiwald, D.A.

    1995-01-01

    Over the years as building and equipment surfaces became contaminated with low levels of uranium or plutonium dust, coats of paint were applied to stabilize the contaminants in place. Most of the earlier paint used was lead-based paint. More recently, various non-lead-based paints, such as two-part epoxy, are used. For D ampersand D (decontamination and decommissioning), it is desirable to remove the paints or other coatings rather than having to tear down and dispose of the entire building. This report describes the use of pulse-repetetion laser systems for the removal of paints and coatings

  2. Laser-based coatings removal

    Energy Technology Data Exchange (ETDEWEB)

    Freiwald, J.G.; Freiwald, D.A. [F2 Associates, Inc., Albuquerque, NM (United States)

    1995-10-01

    Over the years as building and equipment surfaces became contaminated with low levels of uranium or plutonium dust, coats of paint were applied to stabilize the contaminants in place. Most of the earlier paint used was lead-based paint. More recently, various non-lead-based paints, such as two-part epoxy, are used. For D&D (decontamination and decommissioning), it is desirable to remove the paints or other coatings rather than having to tear down and dispose of the entire building. This report describes the use of pulse-repetetion laser systems for the removal of paints and coatings.

  3. Novel Formulations of Phase Change Materials—Epoxy Composites for Thermal Energy Storage

    OpenAIRE

    Maria Elena Arce; Miguel Angel Alvarez Feijoo; Andres Suarez Garcia; Claudia C. Luhrs

    2018-01-01

    This research aimed to evaluate the thermal properties of new formulations of phase change materials (PCMs)-epoxy composites, containing a thickening agent and a thermally conductive phase. The composite specimens produced consisted of composites fabricated using (a) inorganic PCMs (hydrated salts), epoxy resins and aluminum particulates or (b) organic PCM (paraffin), epoxy resins, and copper particles. Differential Scanning Calorimetry (DSC) was used to analyze the thermal behavior of the sa...

  4. Evaluation of Nanomaterial Approaches to Damping in Epoxy Resin and Carbon Fiber/Epoxy Composite Structures by Dynamic Mechanical Analysis

    Science.gov (United States)

    Miller, G.; Heimann, Paula J.; Scheiman, Daniel A.; Duffy, Kirsten P.; Johnston, J. Chris; Roberts, Gary D.

    2013-01-01

    Vibration mitigation in composite structures has been demonstrated through widely varying methods which include both active and passive damping. Recently, nanomaterials have been investigated as a viable approach to composite vibration damping due to the large surface available to generate energy dissipation through friction. This work evaluates the influence of dispersed nanoparticles on the damping ratio of an epoxy matrix. Limited benefit was observed through dispersion methods, however nanoparticle application as a coating resulting in up to a three-fold increase in damping.

  5. Superhydrophobic ceramic coating: Fabrication by solution precursor plasma spray and investigation of wetting behavior.

    Science.gov (United States)

    Xu, Pengyun; Coyle, Thomas W; Pershin, Larry; Mostaghimi, Javad

    2018-03-16

    Superhydrophobic surfaces are often created by fabricating suitable surface structures from low-surface-energy organic materials using processes that are not suitable for large-scale fabrication. Rare earth oxides (REO) exhibit hydrophobic behavior that is unusual among oxides. Solution precursor plasma spray (SPPS) deposition is a rapid, one-step process that can produce ceramic coatings with fine scale columnar structures. Manipulation of the structure of REO coatings through variation in deposition conditions may allow the wetting behavior to be controlled. Yb 2 O 3 coatings were fabricated via SPPS. Coating structure was investigated by scanning electron microscopy, digital optical microscopy, and x-ray diffraction. The static water contact angle and roll-off angle were measured, and the dynamic impact of water droplets on the coating surface recorded. Superhydrophobic behavior was observed; the best coating exhibited a water contact angle of ∼163°, a roll-off angle of ∼6°, and complete droplet rebound behavior. All coatings were crystalline Yb 2 O 3 , with a nano-scale roughness superimposed on a micron-scale columnar structure. The wetting behaviors of coatings deposited at different standoff distances were correlated with the coating microstructures and surface topographies. The self-cleaning, water flushing and water jetting tests were conducted and further demonstrated the excellent and durable hydrophobicity of the coatings. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Evaluation of several corrosion protective coating systems on aluminum

    Science.gov (United States)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  7. Facile fabrication of superhydrophobic films with fractal structures using epoxy resin microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Yun-Yun; Zhang, Li-Zhi, E-mail: lzzhang@scut.edu.cn

    2014-02-15

    A simple method has been developed to fabricate superhydrophobic surfaces with fractal structures with epoxy resin microspheres (ERMs). The ERMs is produced by phase separation in an epoxy-amine curing system with a silica sol (SS) dispersant. The transparent epoxy solution becomes cloudy and turns into epoxy suspension (ES) in this process. The fractal structure (two tier structure) generated by synthetic epoxy resin microspheres (ERMs) and deposited nanoincrutations on the surfaces of these ERMs, which have been observed by scanning electron microscope (SEM). The curing time of ES is an important condition to obtain films with good comprehensive performances. Superhydrophobic films can be prepared by adding extra SS into ES with a curing time longer than 5 h. The optimal curing time is 10 h to fabricate a film with good mechanical stability and high superhydrophobicity. In addition, a surface with anti-wetting property of impacting microdroplets can be fabricated by prolonging the curing time of ES to 24 h. The gradually decreased hydrophilic groups resulted from a longer curing time enable the surface to have smaller surface adhesions to water droplets, which is the main reason to keep its superhydrophobicity under impacting conditions. The coated surface is highly hydrophobic and the impacting water droplets are bounced off from the surface.

  8. Facile fabrication of superhydrophobic films with fractal structures using epoxy resin microspheres

    Science.gov (United States)

    Quan, Yun-Yun; Zhang, Li-Zhi

    2014-02-01

    A simple method has been developed to fabricate superhydrophobic surfaces with fractal structures with epoxy resin microspheres (ERMs). The ERMs is produced by phase separation in an epoxy-amine curing system with a silica sol (SS) dispersant. The transparent epoxy solution becomes cloudy and turns into epoxy suspension (ES) in this process. The fractal structure (two tier structure) generated by synthetic epoxy resin microspheres (ERMs) and deposited nanoincrutations on the surfaces of these ERMs, which have been observed by scanning electron microscope (SEM). The curing time of ES is an important condition to obtain films with good comprehensive performances. Superhydrophobic films can be prepared by adding extra SS into ES with a curing time longer than 5 h. The optimal curing time is 10 h to fabricate a film with good mechanical stability and high superhydrophobicity. In addition, a surface with anti-wetting property of impacting microdroplets can be fabricated by prolonging the curing time of ES to 24 h. The gradually decreased hydrophilic groups resulted from a longer curing time enable the surface to have smaller surface adhesions to water droplets, which is the main reason to keep its superhydrophobicity under impacting conditions. The coated surface is highly hydrophobic and the impacting water droplets are bounced off from the surface.

  9. Magnetic properties of permalloy-coated organic tubules

    Science.gov (United States)

    Krebs, J. J.; Rubinstein, M.; Lubitz, P.; Harford, M. Z.; Baral, S.; Shashidar, R.; Ho, Y. S.; Chow, G. M.; Qadri, S.

    1991-11-01

    An initial investigation is presented of the ferromagnetic properties of a novel type of magnetic composite, viz., permalloy-coated submicron diameter hollow cylinders or tubules. The tubules form spontaneously from an organic material, a diacetylenic phosopholipid, and were used as templates on which the ferromagnetic material was deposited by electroless deposition. The permalloy-coated tubules were dispersed in an epoxy matrix to measure the magnetization and ferromagnetic resonance (FMR) properties of individual tubules. The nature of the magnetic anisotropy and the FMR spectra observed confirmed that the tubules are well aligned by a magnetic field during the epoxy curing. The FMR spectra are interpreted in terms of a powder pattern distribution of thin-film spectra consistent with the large diameter-to-thickness ratio.

  10. Fusion bonded epoxy mainline and field joint coatings performance from the X100 field trial – A case study

    International Nuclear Information System (INIS)

    Jadoon, A.N.K.; Thompson, I.

    2012-01-01

    Operating and distribution companies are potentially interested in the use of high and ultra-high strength steels for the transportation of high pressure gas. The ultra-high strength X100 grade steel was commercially developed as a potential option to meet this. However, there has been limited industry wide use of X100 to date. BP carried out a 2 year field trial to demonstrate the operational capacity and integrity of a large diameter (48 inch/1219 mm) high pressure pipeline constructed from X100 grade steel. The 800 m pipeline was buried in a clay backfill and exposed to wet ground conditions associated with the North of England. Flow pressure cycling was carried out, using water, to simulate 40 years of operational service. A 200 m section of the pipeline was exposed to three different potential (cathodic protection) zones for the duration of the trial: zero potential, intermediate potential (−850 to −950 mV) and high potential (−1200 to −1300 mV). This section also had damage and defects induced which are typically associated with bad installation and commissioning. An area of potential concern is the degradation of the mechanical properties (strain ageing) due to the external coating application temperature. Thus, a low coating application temperature is deemed desirable. The mainline and field joint coatings employed for the trial were fusion bonded epoxy (FBE). Both of these have been used in other BP projects, with a good track record. They were applied at a lower application temperature of 220 °C, compared to the more typical 230–240 °C. The lower application temperature was within the manufacturers approved application and curing temperature range. The lower temperature was used to assess the ultimate performance properties of the mainline and field joint FBE coatings. Mainline and field joint coating samples were taken from the three different potential zones and extensive testing and characterisation carried out. This paper presents and

  11. A novel fabrication of a high performance SiO(2)-graphene oxide (GO) nanohybrids: Characterization of thermal properties of epoxy nanocomposites filled with SiO(2)-GO nanohybrids.

    Science.gov (United States)

    Haeri, S Z; Ramezanzadeh, B; Asghari, M

    2017-05-01

    In this study it has been aimed to enhance the thermal resistance of epoxy coating through incorporation of SiO 2 -GO nanohybrids. SiO 2 -GO nanohybrids were synthesized through one-step sol-gel route using a mixture of Tetraethylorthosilane (TEOS) and 3-Aminopropyl triethoxysilane (APTES) silanes. The SiO 2 -GO nanohybrids were prepared at various hydrolysis times of 24, 48 and 72h. Then 0.2wt.% of GO and SiO 2 -GO nanohybrids were separately incorporated into the epoxy coating. Results revealed that amino functionalized SiO 2 nanoparticles with particle size around 20-30nm successfully synthesized on the basal plane of GO. Results showed significant improvement of dispersion and interfacial interactions between nanohybrids and epoxy composite arising from covalent bonding between the SiO 2 -GO and the epoxy matrix. It was found that the thermal resistance of SiO 2 -GO nanohybrids and SiO 2 -GO/Epoxy nanocomposite was noticeably higher than GO and epoxy matrix, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. In vitro corrosion behavior of bioceramic, metallic, and bioceramic-metallic coated stainless steel dental implants.

    Science.gov (United States)

    Fathi, M H; Salehi, M; Saatchi, A; Mortazavi, V; Moosavi, S B

    2003-05-01

    The most common metals and alloys used in dentistry may be exposed to a process of corrosion in vivo that make them cytotoxic. The biocompatibility of dental alloys is primarily related to their corrosion behavior. The aim of this work was to evaluate the corrosion behavior and thus the biocompatibility of the uncoated and coated stainless steels and compare the effect of type of coatings on corrosion behavior. Three types of coatings, hydroxyapatite (HA), titanium (Ti), and a double-layer HA/Ti on AISI 316L stainless steel were made. HA coating was produced using plasma-spraying technique and Ti coating was made using physical vapor deposition process. In order to perform a novel double-layer composite coating, a top layer of HA was plasma-sprayed over a physical vapor deposited Ti layer on AISI 316L stainless steel. Structural characterization techniques including XRD, SEM and EDX were used to investigate the microstructure, morphology and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility. Double-layer HA/Ti coating on AISI 316L SS had a positive effect on improvement of corrosion behavior. The decrease in corrosion current densities was significant for these coated specimens and was much lower than the values obtained for uncoated and single HA coated specimens. Ti coating on AISI 316L SS also has a beneficial effect on corrosion behavior. The results were compared with the results of corrosion behavior of HA coated commercially pure titanium (cpTi) and uncoated cpTi. These results demonstrated that the double-layer HA/Ti coated 316L SS can be used as an endodontic implant and two goals including improvement of corrosion resistance and bone osteointegration can be obtained simultaneously.

  13. Flexural creep behavior of epoxy/cotton composite materials before and after saline absorption for orthopedics applications

    Science.gov (United States)

    Kontaxis, L. C.; Georgali, A.; Portan, D. V.; Papanicolaou, G. C.

    2018-02-01

    In the present study, epoxy resin-non-woven cotton fibers fabric composite plates were manufactured by using the vacuum infusion technique. Next, flexural creep-recovery experiments were performed in order to study the viscoelastic behavior of both the neat resin and the composite material manufactured under both dry and wet conditions. A low cost, mechanically operated flexural creep testing machine was designed and manufactured according to ASTM standards, for providing an economical means of performing flexural creep experiments. Initially, specimens were immersed in physiological saline for different periods of time at constant temperature of 37°C and subsequently tested under flexural creep conditions in order to study the effect of saline absorption on the creep-recovery behavior of the composites. The specific environmental conditions were chosen such as to simulate the real conditions existed into the human body. The combined effect of applied stress, time of immersion, creep time and amount of saline absorbed on the overall flexural viscoelastic behavior of composites was studied. The maximum amount of saline absorbed by the composites was 3.2%, which is double the saline intake of pure resin. It is believed that the 1.5% extra saline was absorbed into the now formed interphase between the matrix and the hydrophobic cotton fibers. It was observed that the creep strain increases as the immersion time increases. This is believed to occur because of the cumulative effect of absorbed saline from the fibers, the matrix, as well as from the fiber-matrix interphase resulting in the fiber matrix debonding and easier relaxation of the macromolecules at higher moisture contents leading to larger deformations at longer times. However, it should be noted that the strain levels of the epoxy resin/cotton fibers fabric composites, never surpassed those of the pure resin, indicating that the fabric successfully reinforces the composite even under the immersion of the

  14. Erosion behavior of W-Ta coatings in plasmas of stationary mirror penning discharges

    International Nuclear Information System (INIS)

    Belous, V.A.; Bondarenko, M.N.; Glazunov, G.P.; Ilchenko, A.V.; Kuprin, A.S.; Konotopskiy, A.L.; Lunyov, V.M.; Ovcharenko, V.D.

    2016-01-01

    Investigations had been carried out of the influence of Ta alloying (2...16 wt.%) in W-coatings on their erosion behavior in steady state plasmas of Penning discharges in different gases: argon, nitrogen, and hydrogen. The coatings were deposited on stainless steel substrates by argon ion sputtering of targets made from appropriate metals. For comparison the erosion behavior had been examined of pure W and Ta coatings obtained by the same method. It was shown the essential decrease of an erosion rate after Ta addition in W coatings. The possible physical mechanism is suggested to explain such erosion behavior

  15. Manufacturing of REBCO coils strongly bonded to cooling members with epoxy resin aimed at its application to Maglev

    International Nuclear Information System (INIS)

    Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi

    2014-01-01

    Highlights: • Paraffin has a risk of losing thermal coupling during cooling down. • We propose an epoxy impregnated REBCO coil co-wound with PTFE tape. • The coil is tightly bonded to cooling members by epoxy resin without the degradation. • We made a REBCO racetrack coil with the same outer dimension as the Maglev magnet. - Abstract: The REBCO coated conductor has been attracted attention because of its high current density in the presence of high magnetic field. If the coated conductor is applied to Maglev, the operational temperature of the on-board magnets will be over 40 K and energy consumption of cryocoolers will be reduced. That high operational temperature also means the absence of liquid helium. Therefore, reliable thermal coupling is desirable for cooling the coils. We propose an epoxy impregnated REBCO coil co-wound with PTFE tape. While the PTFE tape prevents the performance degradation of the coil, the epoxy resin bonds the coil to cooling members. We carried out three experiments to confirm that the coil structure which we propose has robust thermal coupling without the degradation. First, thermal resistances of paraffin and epoxy were measured varying the temperature from room temperature to 10 K. The measurement result indicates that paraffin has a risk of losing thermal coupling during cooling down. In another experiment, PTFE (polytetrafluoroethylene) tape insulator prevented performance degradation of a small epoxy impregnated REBCO coil, while another REBCO coil with polyimide tape showed clear performance degradation. Finally, we produced a racetrack REBCO coil with the same outer dimension as a Maglev on-board magnet coil. Although the racetrack coil was installed in a GFRP coil case and tightly bonded to the case by epoxy impregnation, any performance degradation was not observed

  16. Manufacturing of REBCO coils strongly bonded to cooling members with epoxy resin aimed at its application to Maglev

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, Katsutoshi, E-mail: mizuno.katsutoshi.14@rtri.or.jp; Ogata, Masafumi; Hasegawa, Hitoshi

    2014-11-15

    Highlights: • Paraffin has a risk of losing thermal coupling during cooling down. • We propose an epoxy impregnated REBCO coil co-wound with PTFE tape. • The coil is tightly bonded to cooling members by epoxy resin without the degradation. • We made a REBCO racetrack coil with the same outer dimension as the Maglev magnet. - Abstract: The REBCO coated conductor has been attracted attention because of its high current density in the presence of high magnetic field. If the coated conductor is applied to Maglev, the operational temperature of the on-board magnets will be over 40 K and energy consumption of cryocoolers will be reduced. That high operational temperature also means the absence of liquid helium. Therefore, reliable thermal coupling is desirable for cooling the coils. We propose an epoxy impregnated REBCO coil co-wound with PTFE tape. While the PTFE tape prevents the performance degradation of the coil, the epoxy resin bonds the coil to cooling members. We carried out three experiments to confirm that the coil structure which we propose has robust thermal coupling without the degradation. First, thermal resistances of paraffin and epoxy were measured varying the temperature from room temperature to 10 K. The measurement result indicates that paraffin has a risk of losing thermal coupling during cooling down. In another experiment, PTFE (polytetrafluoroethylene) tape insulator prevented performance degradation of a small epoxy impregnated REBCO coil, while another REBCO coil with polyimide tape showed clear performance degradation. Finally, we produced a racetrack REBCO coil with the same outer dimension as a Maglev on-board magnet coil. Although the racetrack coil was installed in a GFRP coil case and tightly bonded to the case by epoxy impregnation, any performance degradation was not observed.

  17. Molecular Modeling of Aerospace Polymer Matrices Including Carbon Nanotube-Enhanced Epoxy

    Science.gov (United States)

    Radue, Matthew S.

    Carbon fiber (CF) composites are increasingly replacing metals used in major structural parts of aircraft, spacecraft, and automobiles. The current limitations of carbon fiber composites are addressed through computational material design by modeling the salient aerospace matrix materials. Molecular Dynamics (MD) models of epoxies with and without carbon nanotube (CNT) reinforcement and models of pure bismaleimides (BMIs) were developed to elucidate structure-property relationships for improved selection and tailoring of matrices. The influence of monomer functionality on the mechanical properties of epoxies is studied using the Reax Force Field (ReaxFF). From deformation simulations, the Young's modulus, yield point, and Poisson's ratio are calculated and analyzed. The results demonstrate an increase in stiffness and yield strength with increasing resin functionality. Comparison between the network structures of distinct epoxies is further advanced by the Monomeric Degree Index (MDI). Experimental validation demonstrates the MD results correctly predict the relationship in Young's moduli for all epoxies modeled. Therefore, the ReaxFF is confirmed to be a useful tool for studying the mechanical behavior of epoxies. While epoxies have been well-studied using MD, there has been no concerted effort to model cured BMI polymers due to the complexity of the network-forming reactions. A novel, adaptable crosslinking framework is developed for implementing 5 distinct cure reactions of Matrimid-5292 (a BMI resin) and investigating the network structure using MD simulations. The influence of different cure reactions and extent of curing are analyzed on the several thermo-mechanical properties such as mass density, glass transition temperature, coefficient of thermal expansion, elastic moduli, and thermal conductivity. The developed crosslinked models correctly predict experimentally observed trends for various properties. Finally, the epoxies modeled (di-, tri-, and tetra

  18. Wear resistance and electrical properties of functionally graded epoxy-resin/silica composites

    International Nuclear Information System (INIS)

    Rihan, Y. A.; Abd El-Bary, B.

    2012-12-01

    In this paper graded Silica/Epoxy composite fabricated by controlled mold filling to obtain a stepwise graded structure. The generated graded structure was controlled by the w 1% content of silica particulates of size range from (45 μm-250 μm). Microstructural characterization was conducted using Scanning Electron Microscope (SEM). Electrical properties were conducted in High Voltage-Lab using Sphere-Plate Electrode System and Insulating resistance equipment s. Wear characteristics were studied using Block-on-Ring wear testing machine for the different layers of the graded silica/epoxy composites, The prepared materials are used as coating materials for the floors of chemical laboratories. (Author)

  19. Laser-based coatings removal

    International Nuclear Information System (INIS)

    Freiwald, J.G.; Freiwald, D.

    1995-01-01

    Over the years as building and equipment surfaces became contaminated with low levels of uranium or plutonium dust, coats of paint were applied to stabilize the contaminants in place. Most of the earlier paint used was lead-based paint. More recently, various non-lead-based paints, such as two-part epoxy, are used. For D ampersand D (decontamination and decommissioning), it is desirable to remove the paints or other coatings rather than having to tear down and dispose of the entire building

  20. Effect of Cross-linking Density on Creep and Recovery Behavior in Epoxy-Based Shape Memory Polymers (SMEPs) for Structural Applications

    Science.gov (United States)

    Rao, Kavitha V.; Ananthapadmanabha, G. S.; Dayananda, G. N.

    2016-12-01

    Epoxy-based shape memory polymers (SMEPs) are gaining importance in the area of aerospace structures due to their high strength and stiffness which is a primary requirement for an SMEP in structural applications. The understanding of viscoelastic behavior of SMEPs is very essential to assess their shape memory effect. In the present work, three types of SMEPs with varying cross-linking densities were developed by curing an aromatic epoxy resin with aliphatic amines. Glass transition temperature ( T g) was measured for these SMEPs using advanced rheometric expansion system, and from the T g measurements, a range of temperatures from glassy to rubbery regimes were chosen. At selected temperatures, creep-recovery tests were performed in order to evaluate the viscoelastic behavior of SMEPs and also to investigate the effect of temperature on creep-recovery. Further, a three-parameter viscoelastic model (Zener) was used to fit the data obtained from experiments. Model parameters like moduli of the springs and viscosity of the dashpot were evaluated by curve fitting. Results revealed that Zener model was well suited to describe the viscoelastic behavior of SMEPs as a function of test temperatures.

  1. The effect of cerium-based conversion treatment on the cathodic delamination and corrosion protection performance of carbon steel-fusion-bonded epoxy coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanzadeh, B., E-mail: ramezanzadeh@aut.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), 16765-654, Tehran (Iran, Islamic Republic of); Rostami, M. [Department of Nanomaterials and Nanocoatings, Institute for Color Science and Technology (ICST), 16765-654, Tehran (Iran, Islamic Republic of)

    2017-01-15

    Highlights: • Steel surface was treated by Ce and acid phosphoric solutions. • Ce treatment considerably enhanced the surface energy and produce nanoscale roughness. • Ce treated samples showed enhanced adhesion to FBE coating. • Ce treatment of steel significantly reduced the FBE cathodic delamination rate. • Ce treated sample showed enhanced corrosion resistance. - Abstract: The effect of surface pre-treatment of pipe surface by green cerium compound and phosphoric acid solution on the fusion-bonded epoxy (FBE) coating performance was studied. The composition and surface morphology of the steel samples treated by acid and Ce solutions were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), equipped with energy dispersive spectroscopy (EDS). Also, the surface free energy was evaluated on these samples through contact angle measurements. In addition, the effect of Ce and acid washing procedures on the adhesion properties and corrosion protection performance of the FBE was examined by pull-off, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results showed that compared to acid washing, the chemical treatment by Ce solution noticeably increased the surface free energy of steel, improved the adhesion properties of FBE, decreased the cathodic delamination rate of FBE, and enhanced the coating corrosion resistance compared to the acid washed samples.

  2. Development of an environmentally benign anticorrosion coating for aluminum alloy using green pigments and organofunctional silanes

    Science.gov (United States)

    Yin, Zhangzhang

    Aerospace aluminum alloys such as Al alloy 2024-T3 and 7075-T6 are subject to localized corrosion due the existence of intermetallics containing Cu, Mg or Zn. Current protection measurement employs substantial use of chromate and high VOC organics, both of which are identified as environment and health hazards. The approach of this study is to utilize a combination of organofunctional silanes and a compatible inhibitor integrated into high-performance waterborne resins. First, an extensive pigment screening has been done to find replacements for chromates using the testing methodology for fast corrosion inhibition evaluation and pigment. Zinc phosphate and calcium zinc phosphomolybdate were found to have the best overall performance on Al alloys. Some new corrosion inhibitors were synthesized by chemical methods or modified by plasma polymerization for use in the coatings. Low-VOC, chromate-free primers (superprimer) were developed using these pigments with silane and acrylic-epoxy resins. The developed superprimer demonstrated good corrosion inhibition on aluminum substrates. The functions of inhibitor and silane in the coating were investigated. Both silane and inhibitor are critical for the performance of the superprimer. Silane was found to improve the adhesion of the coating to the substrate and also facilitate corrosion prevention. Addition of zinc phosphate to the coating improved the resistance of a scratched area against corrosion. The microstructure of the acrylic-epoxy superprimer coating was studied. SEM/EDAX revealed that the superprimer has a self-assembled stratified double-layer structure which accounts for the strong anti-corrosion performance of the zinc phosphate pigment. Zinc phosphate leaches out from the coating to actively protect the scratched area. The leaching of pigment was confirmed in the ICP-MS analysis and the leaching rate was measured. Coating-metal interface and the scribe of coated panels subjected to corrosion test was studied

  3. Influence on the anticorrosive properties of the use of erbium (III) trifluoromethanesulfonate as initiator in an epoxy powder clearcoat

    International Nuclear Information System (INIS)

    Garcia, S.J.; Suay, J.

    2007-01-01

    New low curing temperature epoxy powder coatings cured cationically by the use of erbium (III) trifluoromethanesulfonate as initiator have been formulated. Their curing kinetics and anticorrosive properties have been studied and compared with a system commonly used in industry (o-tolylbiguanide/epoxy resin). Three different tests of anticorrosive properties (EIS, AC/DC/AC, and salt fog spray) have been used together with an adherence test, in order to establish the optimal system. Results show that a system employing 1 phr of erbium triflate presents good anticorrosive properties. The technique AC/DC/AC has shown its ability to evaluate properly, much faster, and in accordance to anticorrosive properties results' of powder coatings obtained by other techniques

  4. Influence on the anticorrosive properties of the use of erbium (III) trifluoromethanesulfonate as initiator in an epoxy powder clearcoat

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, S.J. [Centro de Biomateriales, Universitat Politecnica de Valencia, Camino de Vera s/n, E-46071 Valencia (Spain)]. E-mail: sangares@upvnet.upv.es; Suay, J. [Centro de Biomateriales, Universitat Politecnica de Valencia, Camino de Vera s/n, E-46071 Valencia (Spain)

    2007-08-15

    New low curing temperature epoxy powder coatings cured cationically by the use of erbium (III) trifluoromethanesulfonate as initiator have been formulated. Their curing kinetics and anticorrosive properties have been studied and compared with a system commonly used in industry (o-tolylbiguanide/epoxy resin). Three different tests of anticorrosive properties (EIS, AC/DC/AC, and salt fog spray) have been used together with an adherence test, in order to establish the optimal system. Results show that a system employing 1 phr of erbium triflate presents good anticorrosive properties. The technique AC/DC/AC has shown its ability to evaluate properly, much faster, and in accordance to anticorrosive properties results' of powder coatings obtained by other techniques.

  5. Electrically Conductive Epoxy Adhesives

    Directory of Open Access Journals (Sweden)

    Lan Bai

    2011-02-01

    Full Text Available Conductive adhesives are widely used in electronic packaging applications such as die attachment and solderless interconnections, component repair, display interconnections, and heat dissipation. The effects of film thickness as functions of filler volume fraction, conductive filler size, shape, as well as uncured adhesive matrix viscosity on the electrical conduction behavior of epoxy-based adhesives are presented in this work. For this purpose, epoxy-based adhesives were prepared using conductive fillers of different size, shape, and types, including Ni powder, flakes, and filaments, Ag powder, and Cu powder. The filaments were 20 μm in diameter, and 160 or 260 μm in length. HCl and H3PO4 acid solutions were used to etch and remove the surface oxide layers from the fillers. The plane resistance of filled adhesive films was measured using the four-point method. In all cases of conductive filler addition, the planar resistivity levels for the composite adhesive films increased when the film thickness was reduced. The shape of resistivity-thickness curves was negative exponential decaying type and was modeled using a mathematical relation. The relationships between the conductive film resistivities and the filler volume fractions were also derived mathematically based on the experimental data. Thus, the effects of surface treatment of filler particles, the type, size, shape of fillers, and the uncured epoxy viscosity could be included empirically by using these mathematical relations based on the experimental data. By utilizing the relations we proposed to model thickness-dependent and volume fraction-dependent conduction behaviors separately, we were able to describe the combined and coupled volume fraction-film thickness relationship mathematically based on our experimental data.

  6. Experimental use of Line-X coated steel pipe piles, Clay Hill Bridge (#2157) replacement project over the Mousam River, Route 9/Western Avenue, Kennebunk, Maine.

    Science.gov (United States)

    2013-02-01

    Steel pipe piles used by MaineDOT for bridge construction are typically coated with a fusion-bonded epoxy (FBE). FBE is a powder-based coating with properties similar to traditional : epoxies. Its name is derived from the process by which it adheres ...

  7. The Relationship Between Coat Color and Aggressive Behaviors in the Domestic Cat.

    Science.gov (United States)

    Stelow, Elizabeth A; Bain, Melissa J; Kass, Philip H

    2016-01-01

    The authors explored a possible relationship between coat color and aggressive behaviors in the domestic cat. This study used an Internet-based survey to collect information on coat color, affiliative behaviors toward cats/humans, agonistic behaviors toward cats/humans, other "problem" behaviors, and cat and guardian demographic data. A total of 1,432 cat guardians completed the online survey; after exclusions based on study protocol, data analysis included 1,274 completed surveys. Guardians reported sex-linked orange female (tortoiseshells, calicos, and "torbies"), black-and-white, and gray-and-white cats to be more frequently aggressive toward humans in 3 settings: during everyday interactions, during handling, and during veterinary visits. Kruskal-Wallis 1-way analysis of variance was used to compare possible differences between the 2 sexes and among different coat colors. Analyses of aggression due to handling, as well as aggression displayed during veterinarian visits, showed little difference among coat colors in these settings.

  8. Effects of Conformal Nanoscale Coatings on Thermal Performance of Vertically Aligned Carbon Nanotubes.

    Science.gov (United States)

    Silvestri, Cinzia; Riccio, Michele; Poelma, René H; Jovic, Aleksandar; Morana, Bruno; Vollebregt, Sten; Irace, Andrea; Zhang, Guo Qi; Sarro, Pasqualina M

    2018-04-17

    The high aspect ratio and the porous nature of spatially oriented forest-like carbon nanotube (CNT) structures represent a unique opportunity to engineer a novel class of nanoscale assemblies. By combining CNTs and conformal coatings, a 3D lightweight scaffold with tailored behavior can be achieved. The effect of nanoscale coatings, aluminum oxide (Al 2 O 3 ) and nonstoichiometric amorphous silicon carbide (a-SiC), on the thermal transport efficiency of high aspect ratio vertically aligned CNTs, is reported herein. The thermal performance of the CNT-based nanostructure strongly depends on the achieved porosity, the coating material and its infiltration within the nanotube network. An unprecedented enhancement in terms of effective thermal conductivity in a-SiC coated CNTs has been obtained: 181% compared to the as-grown CNTs and Al 2 O 3 coated CNTs. Furthermore, the integration of coated high aspect ratio CNTs in an epoxy molding compound demonstrates that, next to the required thermal conductivity, the mechanical compliance for thermal interface applications can also be achieved through coating infiltration into foam-like CNT forests. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Novel Formulations of Phase Change Materials—Epoxy Composites for Thermal Energy Storage

    Science.gov (United States)

    Alvarez Feijoo, Miguel Angel

    2018-01-01

    This research aimed to evaluate the thermal properties of new formulations of phase change materials (PCMs)-epoxy composites, containing a thickening agent and a thermally conductive phase. The composite specimens produced consisted of composites fabricated using (a) inorganic PCMs (hydrated salts), epoxy resins and aluminum particulates or (b) organic PCM (paraffin), epoxy resins, and copper particles. Differential Scanning Calorimetry (DSC) was used to analyze the thermal behavior of the samples, while hardness measurements were used to determine changes in mechanical properties at diverse PCM and conductive phase loading values. The results indicate that the epoxy matrix can act as a container for the PCM phase without hindering the heat-absorbing behavior of the PCMs employed. Organic PCMs presented reversible phase transformations over multiple cycles, an advantage that was lacking in their inorganic counterparts. The enthalpy of the organic PCM-epoxy specimens increased linearly with the PCM content in the matrix. The use of thickening agents prevented phase segregation issues and allowed the fabrication of specimens containing up to 40% PCM, a loading significantly higher than others reported. The conductive phase seemed to improve the heat transfer and the mechanical properties of the composites when present in low percentages (phase combination (PCM + epoxy resin + hardener + thickening agent) presents great potential as a heat-absorbing material at the temperatures employed. PMID:29373538

  10. The Relationship Between Coat Color and Aggressive Behaviors in the Domestic Cat

    OpenAIRE

    Stelow, EA; Bain, MJ; Kass, PH

    2015-01-01

    © 2016 Taylor & Francis. The authors explored a possible relationship between coat color and aggressive behaviors in the domestic cat. This study used an Internet-based survey to collect information on coat color, affiliative behaviors toward cats/humans, agonistic behaviors toward cats/humans, other “problem” behaviors, and cat and guardian demographic data. A total of 1,432 cat guardians completed the online survey; after exclusions based on study protocol, data analysis included 1,274 co...

  11. Multifunctionality in epoxy/glass fibers composites with graphene interphase

    OpenAIRE

    Mahmood, Haroon

    2017-01-01

    In this project, the synergetic effect of a graphene interphase in epoxy/glass fibers composites was investigated by coating glass fibers (GF) with graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets by an electrophoretic deposition (EPD) technique. Graphite oxide was prepared using modified Hummers method in which raw graphite powder was oxidized using potassium permanganate (KMnO4) in acidic solution. Using ultrasonic technique, the graphite oxide was dispersed homogenously in w...

  12. Thermoset coatings from epoxidized sucrose soyate and blocked, bio-based dicarboxylic acids.

    Science.gov (United States)

    Kovash, Curtiss S; Pavlacky, Erin; Selvakumar, Sermadurai; Sibi, Mukund P; Webster, Dean C

    2014-08-01

    A new 100% bio-based thermosetting coating system was developed from epoxidized sucrose soyate crosslinked with blocked bio-based dicarboxylic acids. A solvent-free, green method was used to block the carboxylic acid groups and render the acids miscible with the epoxy resin. The thermal reversibility of this blocking allowed for the formulation of epoxy-acid thermoset coatings that are 100% bio-based. This was possible due to the volatility of the vinyl ethers under curing conditions. These systems have good adhesion to metal substrates and perform well under chemical and physical stress. Additionally, the hardness of the coating system is dependent on the chain length of the diacid used, making it tunable. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Improving Mechanical Properties of Thermoset Biocomposites by Fiber Coating or Organic Oil Addition

    Directory of Open Access Journals (Sweden)

    Truc T. Ngo

    2015-01-01

    Full Text Available Two different thermoset biocomposite systems are experimented in this study with the hope to improve their mechanical properties. Fiberglass and hemp, in form of fabrics, are used to reinforce the thermoset polymer matrix, which includes a traditional epoxy resin and a linseed oil-based bioresin (UVL. The fiber/polymer matrix interface is modified using two different approaches: adding a plant-based oil (pine or linseed to the polymer matrix or coating the fibers with 3-(aminopropyltriethoxysilane (APTES prior to integrating them into the polymer matrix. Epoxy resin is cured using an amine-based initiator, whereas UVL resin is cured under ultraviolet light. Results show that hemp fibers with APTES prime coat used in either epoxy or UVL matrix exhibit some potential improvements in the composite’s mechanical properties including tensile strength, modulus of elasticity, and ductility. It is also found that adding oil to the epoxy matrix reinforced with fiberglass mostly improves the material’s modulus of elasticity while maintaining its tensile strength and ductility. However, adding oil to the epoxy matrix reinforced with hemp doubles the material’s ductility while slightly reducing its tensile strength and modulus of elasticity.

  14. Role of Interphase in the Mechanical Behavior of Silica/Epoxy Resin Nanocomposites

    Directory of Open Access Journals (Sweden)

    Yi Hua

    2015-06-01

    Full Text Available A nanoscale representative volume element has been developed to investigate the effect of interphase geometry and property on the mechanical behavior of silica/epoxy resin nanocomposites. The role of interphase–matrix bonding was also examined. Results suggested that interphase modulus and interfacial bonding conditions had significant influence on the effective stiffness of nanocomposites, while its sensitivities with respect to both the thickness and the gradient property of the interphase was minimal. The stiffer interphase demonstrated a higher load-sharing capacity, which also increased the stress distribution uniformity within the resin nanocomposites. Under the condition of imperfect interfacial bonding, the effective stiffness of nanocomposites was much lower, which was in good agreement with the documented experimental observations. This work could shed some light on the design and manufacturing of resin nanocomposites.

  15. Electrosprayed core–shell solid dispersions of acyclovir fabricated using an epoxy-coated concentric spray head

    Science.gov (United States)

    Liu, Zhe-Peng; Cui, Lei; Yu, Deng-Guang; Zhao, Zhuan-Xia; Chen, Lan

    2014-01-01

    A novel structural solid dispersion (SD) taking the form of core–shell microparticles for poorly water-soluble drugs is reported for the first time. Using polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix, the SDs were fabricated using coaxial electrospraying (characterized by an epoxy-coated concentric spray head), although the core fluids were unprocessable using one-fluid electrospraying. Through manipulating the flow rates of the core drug-loaded solutions, two types of core–shell microparticles with tunable drug contents were prepared. They had average diameters of 1.36±0.67 and 1.74±0.58 μm, and were essentially a combination of nanocomposites with the active ingredient acyclovir (ACY) distributed in the inner core, and the sweeter sucralose and transmembrane enhancer sodium dodecyl sulfate localized in the outer shell. Differential scanning calorimetry and X-ray diffraction results demonstrated that ACY, sodium dodecyl sulfate, and sucralose were well distributed in the PVP matrix in an amorphous state because of favorable second-order interactions. In vitro dissolution and permeation studies showed that the core–shell microparticle SDs rapidly freed ACY within 1 minute and promoted nearly eightfold increases in permeation rate across the sublingual mucosa compared with raw ACY powders. PMID:24790437

  16. Characterization of red mud-epoxy intumescent char using surface imaging and micro analysis

    Energy Technology Data Exchange (ETDEWEB)

    Arogundade, A. I., E-mail: ajiunolorioba@gmail.com; Megat-Yusoff, P. S. M., E-mail: puteris@petronas.com.my; Faiz, A. [Department of Mechanical Engineering, Universiti Tecknologi Petronas (Malaysia); Bhat, A. H. [Department of Fundamental and Applied Science, Universiti Tecknologi Petronas (Malaysia)

    2015-07-22

    In this study, red mud (RM), an oxide waste was proposed as reinforcing, synergistic filler for the traditional epoxy intumescent coating (IC). 5.5 wt% of acid-modified and unmodified red mud were introduced into the basic intumescent formulation of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL). In order to predict effect of modification on its suitability, Field emission electron scanning microscopy and Fourier transform infra red were used to obtain detailed characteristics such as the cell size, pore distribution, homogeneity and chemical composition of the red mud-epoxy carbonaceous char. Both acid-modified and unmodified RM-filled ICs produced chars with smaller and more closely packed cells compared to chars from the unfilled coating. Both coating types had hard carbonaceous metal phosphate coverings that could act as heat barriers. The unmodified red mud was found to be antagonistic to the intumescent action with an expansion of only 2 times the initial thickness. The leached, low iron-red mud produced an expansion of 15 times the initial thickness, but possessed a hollow interior. From these findings, it may be deduced that while acid leaching of red mud may improve intumescent expansion, it would be necessary to optimize the percent filler loading to improve residual mass.

  17. Metallographic techniques for evaluation of thermal barrier coatings

    Science.gov (United States)

    Brindley, William J.; Leonhardt, Todd A.

    1990-01-01

    The performance of ceramic thermal barrier coatings is strongly dependent on the amount and shape of the porosity in the coating. Current metallographic techniques do not provide polished surfaces that are adequate for a repeatable interpretation of the coating structures. A technique recently developed at NASA-Lewis for preparation of thermal barrier coating sections combines epoxy impregnation, careful sectioning and polishing, and interference layering to provide previously unobtainable information on processing-induced porosity. In fact, increased contrast and less ambiguous structure developed by the method make automatic quantitative metallography a viable option for characterizing thermal barrier coating structures.

  18. Thermo-structural analysis and electrical conductivity behavior of epoxy/metals composites

    Science.gov (United States)

    Boumedienne, N.; Faska, Y.; Maaroufi, A.; Pinto, G.; Vicente, L.; Benavente, R.

    2017-05-01

    This paper reports on the elaboration and characterization of epoxy resin filled with metallic particles powder (aluminum, tin and zinc) composites. The scanning electron microscopy (SEM) pictures, density measurements and x-ray diffraction analysis (DRX) showed a homogeneous phase of obtained composites. The differential scanning calorimetry revealed a good adherence at matrix-filler interfaces, confirming the SEM observations. The measured glass transition temperatures depend on composites fillers' nature. Afterwards, the electrical conductivity of composites versus their fillers' contents has been investigated. The obtained results depict a nonlinear behavior, indicating an insulator to conductor phase transition at a conduction threshold; with high contrast of ten decades. Hence, the elaborated materials give a possibility to obtain dielectric or electrically conducting phases, which can to be interesting in the choice of desired applications. Finally, the obtained results have been successfully simulated on the basis of different percolation models approach combined with structural characterization inferences.

  19. Hybrid Ultra-Low VOC and Non-HAP Rain Erosion Coatings

    Science.gov (United States)

    2018-01-12

    provide excellent rain erosion resistance, superior mechanical properties, good adhesion to the substrate and meet a host of other metrics outlined in MIL... common urethane and/or epoxy topcoat systems based on their high impact energy and erosive nature. Specialty formulations are thus required to...in films having excellent performance properties. The most common high performance two-component coatings are epoxy systems and isocyanate based

  20. Coating Performance in Duluth Superior Harbor. Part 2

    Science.gov (United States)

    2012-10-01

    tures in fresh water , and nine coatings were evaluated for corrosion protection of CS coupons and I-beams around DSH after 46 and 35 months...following coatings were selected for this evaluation: 1 Aquapure HR* 2 Chevron Phillips 1ZSMV 3 Standard epoxy 4 HumidurML* 5 Wasser MC-zinc/MC-tar* 6...one option for protection of extensive structures in fresh water , and nine coatings were evaluated for corrosion protection of CS coupons and I-beams

  1. Creep behavior of an epoxy resin and an epoxy-based FRP in condition of simultaneous supply of radiation and stress at cryogenic temperatures

    International Nuclear Information System (INIS)

    Nishiura, Tetsuya; Nishijima, Shigehiro; Okada, Toichi

    1995-01-01

    Creep tests of an epoxy resin and an epoxy-based FRP in bending under irradiation condition have been carried out, to investigate the synergistic effects of radiation and stress on mechanical properties of FRP. Simultaneous supply of stress and irradiation on the epoxy resin and the FRP enhanced creep rates in comparison with that supply of the stress on a post-irradiated one did. ESR spectra measurement was also carried out to study the change of molecule of the resin irradiated. Increase of molecular weight between crosslinks was found out to be enhanced by the synergistic effect of radiation and stress. The mechanism of increased damage of FRP induced by the effects of simultaneous stress and irradiation is discussed. (author)

  2. How PE tape performs under concrete coating

    International Nuclear Information System (INIS)

    Dritt, H.J.

    1984-01-01

    The program objectives were to evaluate the performance of polyethylene tape plant coating and fusion bonded epoxy powder systems with particular respect to the following: 1. Concrete coating application procedures; 2. The shear resistance during laying and retrieving operations of the coating at the various interfaces (a) Pipe and anti-corrosion coating; (b) Anti-corrosion coating and outerwrap; (c) Overlap areas of the anti-corrosion and outerwrap layers; (d) Between concrete and the various corrosion coatings during laying and retrieving operations. 3. Resistance to damage of the coating as a consequence of cracking or slippage of the concrete weight coating. 4. Ability of various coatings to withstand the damage during concrete application by both impact and compression methods; 5. Evaluation of tape and shrink sleeve joint coatings at the cut-back area as well as performance of tape under hot asphalt coating

  3. Colorless triphenylamine-based aliphatic thermoset epoxy for multicolored and near-infrared electrochromic applications.

    Science.gov (United States)

    Chuang, Ya-Wen; Yen, Hung-Ju; Wu, Jia-Hao; Liou, Guey-Sheng

    2014-03-12

    In this study, two novel colorless thermoset epoxy resins with anodically electrochromism were prepared from the thermal curing of two triphenylamine-based diamine monomers, 4,4'-diamino-4″-methoxytriphenylamine (1) and N,N'-bis(4-aminophenyl)-N,N'-di(4-methoxylphenyl)-1,4-phenylenediamine (2) with aliphatic epoxy triglycidyl isocyanurate, respectively. The resulting thermoset epoxy resins showed excellent softening temperature (Ts, 270 and 280 °C) due to the rigid structure and highly crosslinking density. In addition, novel colorless epoxy resin films revealed good reversible electrochemical oxidation and interesting multi-electrochromic behavior with high contrast ratio both in visible and near-infrared regions. The aliphatic thermoset epoxy resins also exhibited high transparency in visible region as colorless and great potential for practical electrochromic applications.

  4. Microstructure and Corrosion Behavior of Ni-Alloy/CrN Nanolayered Coatings

    Directory of Open Access Journals (Sweden)

    Hao-Hsiang Huang

    2011-01-01

    Full Text Available The Ni-alloy/CrN nanolayered coatings, Ni-Al/CrN and Ni-P/CrN, were deposited on (100 silicon wafer and AISI 420 stainless steel substrates by dual-gun sputtering technique. The influences of the layer microstructure on corrosion behavior of the nanolayered thin films were investigated. The bilayer thickness was controlled approximately 10 nm with a total coating thickness of 1m. The single-layer Ni-alloy and CrN coatings deposited at 350∘C were also evaluated for comparison. Through phase identification, phases of Ni-P and Ni-Al compounds were observed in the single Ni-alloy layers. On the other hand, the nanolayered Ni-P/CrN and Ni-Al/CrN coatings showed an amorphous/nanocrystalline microstructure. The precipitation of Ni-Al and Ni-P intermetallic compounds was suppressed by the nanolayered configuration of Ni-alloy/CrN coatings. Through Tafel analysis, the corr and corr values ranged from –0.64 to –0.33 V and 1.42×10−5 to 1.14×10−6 A/cm2, respectively, were deduced for various coating assemblies. The corrosion mechanisms and related behaviors of the coatings were compared. The coatings with a nanolayered Ni-alloy/CrN configuration exhibited a superior corrosion resistance to single-layer alloy or nitride coatings.

  5. Novel Formulations of Phase Change Materials-Epoxy Composites for Thermal Energy Storage.

    Science.gov (United States)

    Arce, Maria Elena; Alvarez Feijoo, Miguel Angel; Suarez Garcia, Andres; Luhrs, Claudia C

    2018-01-26

    This research aimed to evaluate the thermal properties of new formulations of phase change materials (PCMs)-epoxy composites, containing a thickening agent and a thermally conductive phase. The composite specimens produced consisted of composites fabricated using (a) inorganic PCMs (hydrated salts), epoxy resins and aluminum particulates or (b) organic PCM (paraffin), epoxy resins, and copper particles. Differential Scanning Calorimetry (DSC) was used to analyze the thermal behavior of the samples, while hardness measurements were used to determine changes in mechanical properties at diverse PCM and conductive phase loading values. The results indicate that the epoxy matrix can act as a container for the PCM phase without hindering the heat-absorbing behavior of the PCMs employed. Organic PCMs presented reversible phase transformations over multiple cycles, an advantage that was lacking in their inorganic counterparts. The enthalpy of the organic PCM-epoxy specimens increased linearly with the PCM content in the matrix. The use of thickening agents prevented phase segregation issues and allowed the fabrication of specimens containing up to 40% PCM, a loading significantly higher than others reported. The conductive phase seemed to improve the heat transfer and the mechanical properties of the composites when present in low percentages (material at the temperatures employed.

  6. Strand Burner Results of AFP-001 Propellant with Inert Coating for Temperature Compensation

    Science.gov (United States)

    2015-10-01

    there were 4 different configurations: baseline, a C-100 coated, an SC-11 coated, and a urethane acrylate (UA) coated. C-100 is a polyurea based...coating, SC-11 is an epoxy-based coating, and UA is a urethane- acrylate -based coating. These coatings were chosen to target a specific strength...Ignition was achieved by running current through a nichrome wire placed on top of the sample. Events were recorded with a Phantom high-speed camera

  7. Novel Formulations of Phase Change Materials—Epoxy Composites for Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Maria Elena Arce

    2018-01-01

    Full Text Available This research aimed to evaluate the thermal properties of new formulations of phase change materials (PCMs-epoxy composites, containing a thickening agent and a thermally conductive phase. The composite specimens produced consisted of composites fabricated using (a inorganic PCMs (hydrated salts, epoxy resins and aluminum particulates or (b organic PCM (paraffin, epoxy resins, and copper particles. Differential Scanning Calorimetry (DSC was used to analyze the thermal behavior of the samples, while hardness measurements were used to determine changes in mechanical properties at diverse PCM and conductive phase loading values. The results indicate that the epoxy matrix can act as a container for the PCM phase without hindering the heat-absorbing behavior of the PCMs employed. Organic PCMs presented reversible phase transformations over multiple cycles, an advantage that was lacking in their inorganic counterparts. The enthalpy of the organic PCM-epoxy specimens increased linearly with the PCM content in the matrix. The use of thickening agents prevented phase segregation issues and allowed the fabrication of specimens containing up to 40% PCM, a loading significantly higher than others reported. The conductive phase seemed to improve the heat transfer and the mechanical properties of the composites when present in low percentages (<10 wt %; however, given its mass, the enthalpy detected in the composites was reduced as their loading further increased. The conductive phase combination (PCM + epoxy resin + hardener + thickening agent presents great potential as a heat-absorbing material at the temperatures employed.

  8. Dual stimuli responsive self-reporting material for chemical reservoir coating

    Science.gov (United States)

    Lee, Tae Hee; Song, Young Kyu; Park, Sun Hee; Park, Young Il; Noh, Seung Man; Kim, Jin Chul

    2018-03-01

    In this study, we introduce a novel dual stimuli responsive self-reporting thiol-epoxy thermoset (DSRTET) coatings which can detect both crack occurrence and pH variation. For crack detection, microcapsule containing tetraphenylethylene (TPE) which exhibits aggregation induced emission (AIE) effect was prepared via multi-step emulsion polymerization and dispersed in DSRTET coatings. For pH variation detection, commercial thymol blue as a pH indicator was added into the polymer matrix. The effect of microcapsule contents in DSRTET on their curing behavior, material properties, and crack sensitivity was characterized using an oscillatory rheology, rigid body pendulum test (RPT), nano-indentation test (NST), universal test machine (UTM) and scratch tester. It was revealed that crack sensitivity of DSRTET coatings was greatly influenced by material properties as well as microcapsule content. The color transition of DSRTET coatings in response to acid or base solution were quantitatively investigated using a multi-angle spectrophotometer after simple acid and base solution drop tests. The color of DSRTET coatings changed from a pale green to red for acidic solution and to blue for basic solution. Finally, The DSRTET used in this study was applied to laboratory scale chemical reservoirs in order to verify the potential as a dual stimuli response self-reporting coating which can detect both crack in coating material and chemical spill caused by the leakage or breakage of the reservoir part.

  9. Enhanced microwave absorption performance of lightweight absorber based on reduced graphene oxide and Ag-coated hollow glass spheres/epoxy composite

    International Nuclear Information System (INIS)

    Wang, Junpeng; Sun, Yu; Chen, Wei; Wang, Tao; Xu, Renxin; Wang, Jun

    2015-01-01

    Using a combination of Ag-coated hollow glass spheres (HGS@Ag) and a small quantity of graphene sheets within the epoxy matrix, we have prepared a novel lightweight high efficiency microwave absorption composite. Compared with pure HGS@Ag and graphene composite, the −10 dB absorption bandwidth and the minimum reflection loss of the novel composite are improved. Reflection loss exceeding −20 dB is obtained for composites in a wide frequency range and the minimum reflection loss reaches −46 dB while bandwidth less than −10 dB can reach up to 4.1 GHz when an appropriate absorber thickness between 2 and 3.5 mm is chosen. The enhanced microwave absorption performance of the novel composite is due to the enhanced dielectric response, enhanced conductivity, and the trap of electromagnetic radiation with increased propagation paths by multiple reflections

  10. Oxidation and thermal shock behavior of thermal barrier coated 18/10CrNi alloy with coating modifications

    Energy Technology Data Exchange (ETDEWEB)

    Guergen, Selim [Vocational School of Transportation, Anadolu University, Eskisehir (Turkmenistan); Diltemiz, Seyid Fehmi [Turkish Air Force1st Air Supply and Maintenance Center Command, Eskisehir (Turkmenistan); Kushan, Melih Cemal [Dept. of Mechanical Engineering, Eskisehir Osmangazi University, Eskisehir (Turkmenistan)

    2017-01-15

    In this study, substrates of 18/10CrNi alloy plates were initially sprayed with a Ni-21Cr-10Al-1Y bond coat and then with an yttria stabilized zirconia top coat by plasma spraying. Subsequently, plasma-sprayed Thermal barrier coatings (TBCs) were treated with two different modification methods, namely, vacuum heat treatment and laser glazing. The effects of modifications on the oxidation and thermal shock behavior of the coatings were evaluated. The effect of coat thickness on the bond strength of the coats was also investigated. Results showed enhancement of the oxidation resistance and thermal shock resistance of TBCs following modifications. Although vacuum heat treatment and laser glazing exhibited comparable results as per oxidation resistance, the former generated the best improvement in the thermal shock resistance of the TBCs. Bond strength also decreased as coat thickness increased.

  11. Role of interfacial effects in carbon nanotube/epoxy nanocomposite behavior.

    Science.gov (United States)

    Pécastaings, G; Delhaès, P; Derré, A; Saadaoui, H; Carmona, F; Cui, S

    2004-09-01

    The interfacial effects are critical to understand the nanocomposite behavior based on polymer matrices. These effects are dependent upon the morphology of carbon nanotubes, the type of used polymer and the processing technique. Indeed, we show that the different parameters, as the eventual surfactant use, the ultrasonic treatment and shear mixing have to be carefully examined, in particular, for nanotube dispersion and their possible alignment. A series of multiwalled nanotubes (MWNT) have been mixed with a regular epoxy resin under a controlled way to prepare nanocomposites. The influence of nanotube content is examined through helium bulk density, glass transition temperature of the matrix and direct current electrical conductivity measurements. These results, including the value of the percolation threshold, are analyzed in relationship with the mesostructural organization of these nanotubes, which is observed by standard and conductive probe atomic force microscopy (AFM) measurements. The wrapping effect of the organic matrix along the nanotubes is evidenced and analyzed to get a better understanding of the final composite characteristics, in particular, for eventually reinforcing the matrix without covalent bonding.

  12. Corrosion electrochemical behaviors of silane coating coated magnesium alloy in NaCl solution containing cerium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Luo, F.; Li, Q.; Zhong, X.K.; Gao, H.; Dai, Y.; Chen, F.N. [School of Chemistry and Chemical Engineering, Southwest University Chongqing (China)

    2012-02-15

    Sol-gel coatings cannot provide adequate corrosion protection for metal/alloys in the corrosive environments due to their high crack-forming potential. This paper demonstrates the possibility to employ cerium nitrate as inhibitor to decrease the corrosion development of sol-gel-based silane coating on the magnesium alloy in NaCl solution. Cerium nitrate was added into the NaCl solution where the silane coating coated magnesium alloy was immersed. Scanning electron microscopy (SEM) was used to examine surface morphology of the silane coating coated magnesium alloy immersed in NaCl solutions doped and undoped with cerium nitrate. The corrosion electrochemical behaviors were investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The results showed that the introduction of cerium nitrate into NaCl solution could effectively inhibit the corrosion of the silane coating coated magnesium alloy. Moreover, the influence of concentration of cerium nitrate on the corrosion inhibition and the possible inhibiting mechanism were also discussed in detail. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Study by dynamic light scattering of an o/w emulsion of an epoxi resin dispersed in water by means of a triblock copolymer of type PEO-PPO-PEO

    International Nuclear Information System (INIS)

    Uscanga, E. H.; Rio, J. M. del; Avendano-Gomez, J. R.

    2009-01-01

    The curing epoxy resins are widely used in various fields of chemical industry, such as adhesives, automotive, coatings, etc. The process operation consisting of flow and mixing of epoxy resins become difficult due to their high viscosity. One solution is to dissolve the epoxy resin in volatile organic solvents (VOS) such as toluene, xylene or benzene. However, the use of VOS is not only expensive but harmful to the environment. (Author)

  14. Sliding wear behavior of E-glass-epoxy/MWCNT composites: An experimental assessment

    Directory of Open Access Journals (Sweden)

    Ravindranadh Bobbili

    2016-03-01

    Full Text Available This investigation has evaluated the sliding wear properties of E-glass-epoxy/MWCNT (multiwalled carbon nanotube composite and Epoxy/MWCNT composite. Four different reinforcements (0, 0.5,1 and 1.5 wt % of MWCNTs are dispersed into an epoxy resin. Design of experiments (DOE and Analysis of variance (ANOVA are employed to understand the relationship between control factors (Percentage of reinforcement, Sliding distance, Sliding velocity and Normal load and response measures (specific wear rate and friction coefficient. The control variables such as sliding distance (300, 600, 900 and 1200 m and normal loads of 10, 15, 20 and 25 N and at sliding velocities of 1, 2, 3 and 4 m/s are chosen for this study. It is observed that that the specific wear rate and friction coefficient can be reduced by the addition of MWCNTs. Scanning electron microscopy (SEM is used to observe the worn surfaces of the samples. Compared with neat epoxy, the composites with MWCNTs showed a lower mass loss, friction coefficient and wear rate and these parameters decreased with the increase of MWCNT percentage. Microscopic investigation of worn out sample fracture surface has revealed that fiber debonding happens when the stresses at the fiber matrix interface exceeds the interfacial strength, causing the fiber to debond from the matrix. The optimum control variables have been derived to reduce both wear and friction coefficient of composites.

  15. Characterization and tribocorrosion behavior of sputtered NiTi coatings

    Energy Technology Data Exchange (ETDEWEB)

    Jin, XiaoMin; Gao, Lizhen [Taiyuan University of Technology (China). College of Environmental Science and Engineering; Wang, Hefeng [Taiyuan University of Technology (China). College of Mechanics; Liu, Erqiang [Taiyuan University of Technology (China). Inst. of Applied Mechanics and Biomedical Engineering

    2016-02-15

    In this study, NiTi coatings were deposited onto AISI 316L stainless steel substrates by closed field unbalanced magnetron sputtering. The microstructure and properties of the coatings were characterized by means of X-ray diffraction, scanning electron microscopy, and nano-indentation. The tribocorrosion resistance and corrosion behavior of the stainless steel substrates and NiTi coatings were investigated in Hanks' solution. The experimental results indicated the NiTi coatings show higher corrosion polarization resistance and a more stable corrosion potential in the Hanks' solution than the uncoated stainless steel substrate. The NiTi coatings also exhibited excellent wear resistance and chemical stability in sliding tests with an Si{sub 3}N{sub 4} ball in the Hanks' solution. The tested samples showed different wear mechanisms in the sliding tests. Compared to the SS substrates, the NiTi coatings were more compatible with the Si{sub 3}N{sub 4} ball.

  16. Preparation and characterization of ultra-thin amphiphobic coatings on silicon wafers

    International Nuclear Information System (INIS)

    Mou, Chun-Yueh; Yuan, Wei-Li; Shih, Chih-Hsin

    2013-01-01

    Fluorine-based amphiphobic coatings have been widely used in commercial domestic utensils and textiles to repel water and oil contaminants. However, few reports from the literature survey have discussed the effects on amphiphobicity of the nano- to micro-scale surface features of such a coating. In this research thin amphiphobic epoxy coatings based on a mixture of bisphenol A diglycidyl ether, tetraethylorthosilicate (TEOS), and a particular alkoxy silane with fluorinated side chains (F-silane) are deposited on silicon wafers. Film amphiphobicity is characterized by the measurement of water and oil contact angles of the coating. Film morphology is revealed in the scanned images using atomic force microscopy. The deposited films free of F-silane are about 10 nm thick. When a small amount of F-silane was firstly added, the water and oil contact angles of the deposited films jumped up to 107° and 69° respectively and then flattened out with increased F-silane. Water droplets gave an average plateau contact angle about 110°, while vegetable oil ones, 40°. It was noted that there is a dramatic decrease in the lyophobicity causing a reduction in contact angles. However, surface lyophobicity also depends on sub-microscopic surface structures. In addition, by increasing TEOS, it was shown that the formed silica sols or granules were helpful in enhancing the mechanical strength along with retaining the lyophobicity of the film. - Highlights: • Epoxy ultrathin films about 10 nm thick deposited on silicon wafer. • Nominal fluorinated silane added to epoxy coatings for amphiphobicity. • Surface lyophobicity retained by sub-micrometer granules in ultrathin coatings. • Film hardness improved by adding tetraethylorthosilicate

  17. Preparation and characterization of ultra-thin amphiphobic coatings on silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Chun-Yueh, E-mail: cymou165@gmail.com; Yuan, Wei-Li; Shih, Chih-Hsin

    2013-06-30

    Fluorine-based amphiphobic coatings have been widely used in commercial domestic utensils and textiles to repel water and oil contaminants. However, few reports from the literature survey have discussed the effects on amphiphobicity of the nano- to micro-scale surface features of such a coating. In this research thin amphiphobic epoxy coatings based on a mixture of bisphenol A diglycidyl ether, tetraethylorthosilicate (TEOS), and a particular alkoxy silane with fluorinated side chains (F-silane) are deposited on silicon wafers. Film amphiphobicity is characterized by the measurement of water and oil contact angles of the coating. Film morphology is revealed in the scanned images using atomic force microscopy. The deposited films free of F-silane are about 10 nm thick. When a small amount of F-silane was firstly added, the water and oil contact angles of the deposited films jumped up to 107° and 69° respectively and then flattened out with increased F-silane. Water droplets gave an average plateau contact angle about 110°, while vegetable oil ones, 40°. It was noted that there is a dramatic decrease in the lyophobicity causing a reduction in contact angles. However, surface lyophobicity also depends on sub-microscopic surface structures. In addition, by increasing TEOS, it was shown that the formed silica sols or granules were helpful in enhancing the mechanical strength along with retaining the lyophobicity of the film. - Highlights: • Epoxy ultrathin films about 10 nm thick deposited on silicon wafer. • Nominal fluorinated silane added to epoxy coatings for amphiphobicity. • Surface lyophobicity retained by sub-micrometer granules in ultrathin coatings. • Film hardness improved by adding tetraethylorthosilicate.

  18. Tribological behavior of duplex coating improved by ion implantation

    International Nuclear Information System (INIS)

    Kakas, D.; Skoric, B.; Rakita, M.

    2004-01-01

    In the present paper the tribological behavior of the coatings are discussed. Duplex coatings were applied on cold working steel 100Cr6. Samples were plasma nitrided at different thickness of plasma surface layers. TiN was deposited with a classic BALZERS PVD equipment and subsequent ion implantation. Ion implantation was provided with N 5+ ions. The other samples were produced with IBAD technology in DANFYSIK chamber. Wear resistance and exchanges of friction coefficient were measured with on-line test using special designed tribology equipment. Following the tests, the wear zone morphology and characteristics of surface layer structure as well as important properties were investigated by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Scratch adhesion testing was performed using commercially available equipment. Energy dispersive X-ray analysis (EDAX) of the wear-scars on pins provided essential information on the wear characteristics. In this paper some results related to influence of duplex coating production methodology on tribological behavior for cold working steel was presented

  19. Effects of Nanofillers on the Thermo-Mechanical Properties and Chemical Resistivity of Epoxy Nanocomposites.

    Science.gov (United States)

    Atchudan, Raji; Pandurangan, Arumugam; Joo, Jin

    2015-06-01

    MWCNTs was synthesized using Ni-Cr/MgO by CVD method and were purified. The purified MWCNT was used as a filler material for the fabrication of epoxy nanocomposites. The epoxy nanocomposites with different amount (wt% = 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0) of nanofillers (CB, SiO2 and MWCNTs) were prepared by casting method. The effects of nanofillers on the properties of neat epoxy matrix were well studied. The thermal properties of nanocomposites were studied using DSC, TGA and flame retardant, and also the mechanical properties such as tensile strength, flexural strength, compressive strength, impact strength, determination of hardness and chemical resistance were studied extensively. Based on the experiment's results, 2 wt% MWCNTs loading in epoxy resin showed the highest improvement in tensile strength, as compared to neat epoxy and to other epoxy systems (CB/epoxy, SiO2/epoxy). Improvements in tensile strength, glass transition temperature and decomposition temperature were observed by the addition of MWCNTs. The mechanical properties of the epoxy nanocomposites were improved due to the interfacial bonding between the MWCNTs and epoxy resin. Strain hardening behavior was higher for MWCNT/epoxy nanocomposites compared with CB/epoxy and SiO2/epoxy nanocomposites. The investigation of thermal and mechanical properties reveals that the incorporation of MWCNTs into the epoxy nanocomposites increases its thermal stability to a great extent. Discrete increase of glass transition temperature of nanocomposites is linearly dependent on MWCNTs content. Due to strong interfacial bonding between MWCNTs and epoxy resin, the chemical resistivity of MWCNT/epoxy nanocomposites is superior to neat epoxy and other epoxy systems.

  20. Coating material composition

    International Nuclear Information System (INIS)

    Kimura, Tadashi; Ozeki, Takao; Kobayashi, Juichi; Nakamoto, Hideo; Maeda, Yutaka.

    1969-01-01

    A coating material composition is provided which can easily be cross-linked by irradiation with active energy, particularly electron beams and ultraviolet light, using a mixture of a prepolymer (a) with an addition reaction product (b). Such compositions have coating properties as good as thermosetting acrylic or amino alkyd resins. The prepolymer (a) is produced by primarily reacting at least 0.1 mol of saturated cyclocarboxylic acid anhydrides and/or alpha-, beta-ethylene unsaturated carboxylic acid anhydrides by addition reaction with one mol of hydroxyl radicals of a basic polymer having a molecular weight of 1,000 to 100,000, the basic polymer being obtained from 1%-40% of a hydroxyl radical containing vinyl monomer and at least 30% of (meth)acrylate monomer. One mol of the sum of hydroxyl radicals and carboxyl radicals of the primary reaction product undergoes a secondary addition reaction with at least 0.1 mol of an epoxy radical-containing vinyl monomer to form the prepolymer(a). The addition reaction product(b) is produced by reacting an epoxy radical-containing vinyl monomer with alpha-, beta-ethylene unsaturated carboxylic acids or their anhydrides. The coating material composition contains a majority of a mixture consisting of 10%-90% of (a) and 90%-10% of (b) above by weight. Four examples of the production of basic polymers, seven examples of the production of prepolymers, seven examples of the production of oligomers, and five examples of applications are given. (Iwakiri, K.)

  1. Thermal Conductivity and Wear Behavior of HVOF-Sprayed Fe-Based Amorphous Coatings

    Directory of Open Access Journals (Sweden)

    Haihua Yao

    2017-10-01

    Full Text Available To protect aluminum parts in vehicle engines, metal-based thermal barrier coatings in the form of Fe59Cr12Nb5B20Si4 amorphous coatings were prepared by high velocity oxygen fuel (HVOF spraying under two different conditions. The microstructure, thermal transport behavior, and wear behavior of the coatings were characterized simultaneously. As a result, this alloy shows high process robustness during spraying. Both Fe-based coatings present dense, layered structure with porosities below 0.9%. Due to higher amorphous phase content, the coating H-1 exhibits a relatively low thermal conductivity, reaching 2.66 W/(m·K, two times lower than the reference stainless steel coating (5.85 W/(m·K, indicating a good thermal barrier property. Meanwhile, the thermal diffusivity of amorphous coatings display a limited increase with temperature up to 500 °C, which guarantees a steady and wide usage on aluminum alloy. Furthermore, the amorphous coating shows better wear resistance compared to high carbon martensitic GCr15 steel at different temperatures. The increased temperature accelerating the tribological reaction, leads to the friction coefficient and wear rate of coating increasing at 200 °C and decreasing at 400 °C.

  2. High Tg and fast curing epoxy-based anisotropic conductive paste for electronic packaging

    Science.gov (United States)

    Keeratitham, Waralee; Somwangthanaroj, Anongnat

    2016-03-01

    Herein, our main objective is to prepare the fast curing epoxy system with high glass transition temperature (Tg) by incorporating the multifunctional epoxy resin into the mixture of diglycidyl ether of bisphenol A (DGEBA) as a major epoxy component and aromatic diamine as a hardener. Furthermore, the curing behavior as well as thermal and thermomechanical properties were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA). It was found that Tg obtained from tan δ of DGEBA/aromatic diamine system increased from 100 °C to 205 °C with the presence of 30 percentage by weight of multifunctional epoxy resin. Additionally, the isothermal DSC results showed that the multifunctional epoxy resin can accelerate the curing reaction of DGEBA/aromatic diamine system. Namely, a high degree of curing (˜90%) was achieved after a few minutes of curing at low temperature of 130 °C, owing to a large number of epoxy ring of multifunctional epoxy resin towards the active hydrogen atoms of aromatic diamine.

  3. Hardness and electrochemical behavior of ceramic coatings on Inconel

    Directory of Open Access Journals (Sweden)

    C. SUJAYA

    2012-03-01

    Full Text Available Thin films of ceramic materials like alumina and silicon carbide are deposited on Inconel substrate by pulsed laser deposition technique using Q-switched Nd: YAG laser. Deposited films are characterized using UV-visible spectrophotometry and X-ray diffraction. Composite microhardness of ceramic coated Inconel system is measured using Knoop indenter and its film hardness is separated using a mathematical model based on area-law of mixture. It is then compared with values obtained using nanoindentation method. Film hardness of the ceramic coating is found to be high compared to the substrates. Corrosion behavior of substrates after ceramic coating is studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The Nyquist and the Bode plots obtained from the EIS data are fitted by appropriate equivalent circuits. The pore resistance, the charge transfer resistance, the coating capacitance and the double layer capacitance of the coatings are obtained from the equivalent circuit. Experimental results show an increase in corrosion resistance of Inconel after ceramic coating. Alumina coated Inconel showed higher corrosion resistance than silicon carbide coated Inconel. After the corrosion testing, the surface topography of the uncoated and the coated systems are examined by scanning electron microscopy.

  4. Temperature dependence of creep compliance of highly cross-linked epoxy: A molecular simulation study

    International Nuclear Information System (INIS)

    Khabaz, Fardin; Khare, Ketan S.; Khare, Rajesh

    2014-01-01

    We have used molecular dynamics (MD) simulations to study the effect of temperature on the creep compliance of neat cross-linked epoxy. Experimental studies of mechanical behavior of cross-linked epoxy in literature commonly report creep compliance values, whereas molecular simulations of these systems have primarily focused on the Young’s modulus. In this work, in order to obtain a more direct comparison between experiments and simulations, atomistically detailed models of the cross-linked epoxy are used to study their creep compliance as a function of temperature using MD simulations. The creep tests are performed by applying a constant tensile stress and monitoring the resulting strain in the system. Our results show that simulated values of creep compliance increase with an increase in both time and temperature. We believe that such calculations of the creep compliance, along with the use of time temperature superposition, hold great promise in connecting the molecular insight obtained from molecular simulation at small length- and time-scales with the experimental behavior of such materials. To the best of our knowledge, this work is the first reported effort that investigates the creep compliance behavior of cross-linked epoxy using MD simulations

  5. Effect of Layer-Graded Bond Coats on Edge Stress Concentration and Oxidation Behavior of Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Ghosn, Louis J.; Miller, Robert A.

    1998-01-01

    Thermal barrier coating (TBC) durability is closely related to design, processing and microstructure of the coating Z, tn systems. Two important issues that must be considered during the design of a thermal barrier coating are thermal expansion and modulus mismatch between the substrate and the ceramic layer, and substrate oxidation. In many cases, both of these issues may be best addressed through the selection of an appropriate bond coat system. In this study, a low thermal expansion and layer-graded bond coat system, that consists of plasma-sprayed FeCoNiCrAl and FeCrAlY coatings, and a high velocity oxyfuel (HVOF) sprayed FeCrAlY coating, is developed to minimize the thermal stresses and provide oxidation resistance. The thermal expansion and oxidation behavior of the coating system are also characterized, and the strain isolation effect of the bond coat system is analyzed using the finite element method (FEM). Experiments and finite element results show that the layer-graded bond coat system possesses lower interfacial stresses. better strain isolation and excellent oxidation resistance. thus significantly improving the coating performance and durability.

  6. Cerium-loaded algae exoskeletons for active corrosion protection of coated AA2024-T3

    International Nuclear Information System (INIS)

    Denissen, Paul J.; Garcia, Santiago J.

    2017-01-01

    Highlights: •Nanoporous diatom algae exoskeletons allow for local inhibitor loading. •Cerium loaded exoskeletons show diffusion controlled release from coatings. •In-situ opto-electrochemical analysis allows for accurate corrosion evaluation. •Raman spectroscopy allows for precise identification of Ce at IMs in a scribe. •High levels of protection were obtained with the Ce-diatom coatings. -- Abstract: The use of micron sized nanoporous diatom algae exoskeletons for inhibitor storage and sustained corrosion protection of coated aluminium structures upon damage is presented. In this concept the algae exoskeleton allows local inhibitor loading, limits the interaction between the cerium and the epoxy/amine coating and allows for diffusion-controlled release of the inhibitor when needed. The inhibitor release and corrosion protection by loaded exoskeletons was evaluated by UV/Vis spectrometry, a home-built optical-electrochemical setup, and Raman spectroscopy. Although this concept has been proven for a cerium-epoxy-aluminium alloy system the main underlying principle can be extrapolated to other inhibitor-coating-metal systems.

  7. Iron-based soft magnetic composites with Mn–Zn ferrite nanoparticles coating obtained by sol–gel method

    International Nuclear Information System (INIS)

    Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zhang, Qian; Zhai, Fuqiang; Logan, Philip; Volinsky, Alex A.

    2012-01-01

    This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn–Zn ferrite nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm, were obtained via the sol–gel method. Scanning electron microscopy, energy dispersive X-ray spectroscopy and distribution maps show that the iron particle surface is covered with a thin layer of Mn–Zn ferrites. Mn–Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced imaginary permeability, increased electrical resistivity and a higher operating frequency of the synthesized magnets. Mn–Zn ferrite coated samples have higher permeability and lower magnetic loss when compared with the non-magnetic epoxy resin coated compacts. The real part of permeability increases by 33.5% when compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature on crystalline phase formation and on the magnetic properties of the Mn–Zn ferrite were investigated via X-ray diffraction and a vibrating sample magnetometer. Ferrites decomposed to FeO and MnO after annealing above 400 °C in nitrogen; thus it is the optimum annealing temperature to attain the desired permeability. - Highlights: ► Uniformly coated Mn–Zn ferrite powder increased the operating frequency of SMCs. ► Compared with epoxy coated, the permeability of SMCs increased by 33.5% at 10 kHz. ► 400 °C is the optimum annealing temperature to attain the desired permeability.

  8. Formulation parameters influencing self-stratification of coatings

    NARCIS (Netherlands)

    Vink, P.; Bots, T.L.

    1996-01-01

    Research was carried out aimed at the development of self-stratifying paints for steel which after application during film formation spontaneously form two well established layers of primer and top coat. The parameters affecting stratification were investigated for combinations of epoxy resins and

  9. Analysis and modeling of delamination factor in drilling of woven kenaf fiber reinforced epoxy using Box Behnken experimental design

    Science.gov (United States)

    Suhaily, M.; Che Hassan, C. H.; Jaharah, A. G.; Afifah, M. A.; Nor Khairusshima, M. K.

    2018-01-01

    In this research study, it presents a comprehensive mathematical model for correlating the influences of drilling parameters on the delamination factor during the drilling of woven kenaf fiber reinforced epoxy composite laminates using the Box Behnken experimental design. The purpose of this study is to investigate the influence of drilling parameters such as cutting speed, feed rate and drill sizes on the delamination produced when drilling woven kenaf reinforced epoxy composite using the non-coated HSS drill bits. The damage generated on the woven kenaf reinforced epoxy composite laminates were observed both at the entrance and exit surface during the drilling operation. The experiments were conducted according to the Box Behnken experimental designs.

  10. Silver nanosheet-coated copper nanowire/epoxy resin nanocomposites with enhanced electrical conductivity and wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Ningning; Ma, Jingyi; Zhang, Yujuan; Yang, Guangbin; Zhang, Shengmao, E-mail: zsm@henu.edu.cn; Zhang, Pingyu [Henan University, Engineering Research Center for Nanomaterials (China)

    2017-03-15

    Silver (Ag) nanosheet-coated Cu nanowires (denoted as Cu@AgNWs) were prepared with a facile transmetalation reaction method. The effect of reaction conditions on the morphology and microstructure of the as-prepared Cu@AgNWs was investigated, and the thermal stability of Cu@AgNWs was evaluated by thermogravimetric analysis. In the meantime, the as-prepared Cu@AgNWs were used as the nanofillers of epoxy resin (EP), and their effect on the electrical conductivity and wear resistance of the EP-matrix composites was examined. Results indicate that the as-prepared Cu@AgNWs consist of CuNW core and Ag nanosheet shell. The Ag nanosheet shell can well inhibit the oxidation of the CuNW core, thereby providing the as-prepared Cu@AgNWs with good thermal stability even at an elevated temperature of 230 °C. The reaction temperature, Cu/Ag molar ratio, Cu dispersion concentration, and the dropping speed of silver ammonia reagent are suggested to be 40 °C, 5:1, 1% (mass fraction), and poured directly, respectively. Resultant Cu@AgNWs exhibit desired morphology and performance and can effectively increase the electrical conductivity and wear resistance of EP. This could make it feasible for the Cu@AgNW-EP composite to be applied as an electrostatic conductive material.

  11. Structure and Corrosion Behavior of Arc-Sprayed Zn-Al Coatings on Ductile Iron Substrate

    Science.gov (United States)

    Bonabi, Salar Fatoureh; Ashrafizadeh, Fakhreddin; Sanati, Alireza; Nahvi, Saied Mehran

    2018-02-01

    In this research, four coatings including pure zinc, pure aluminum, a double-layered coating of zinc and aluminum, and a coating produced by simultaneous deposition of zinc and aluminum were deposited on a cast iron substrate using electric arc-spraying technique. The coatings were characterized by XRD, SEM and EDS map and spot analyses. Adhesion strength of the coatings was evaluated by three-point bending tests, where double-layered coating indicated the lowest bending angle among the specimens, with detection of cracks at the coating-substrate interface. Coatings produced by simultaneous deposition of zinc and aluminum possessed a relatively uniform distribution of both metals. In order to evaluate the corrosion behavior of the coatings, cyclic polarization and salt spray tests were conducted. Accordingly, pure aluminum coating showed susceptibility to pitting corrosion and other coatings underwent uniform corrosion. For double-layered coating, SEM micrographs revealed zinc corrosion products as flaky particles in the pores formed by pitting on the surface, an indication of penetration of corrosion products from the lower layer (zinc) to the top layer (aluminum). All coatings experienced higher negative corrosion potentials than the iron substrate, indicative of their sacrificial behavior.

  12. Static vs dynamic settlement and adhesion of diatoms to ship hull coatings.

    Science.gov (United States)

    Zargiel, Kelli A; Swain, Geoffrey W

    2014-01-01

    Many experiments utilize static immersion tests to evaluate the performance of ship hull coatings. These provide valuable data; however, they do not accurately represent the conditions both the hull and fouling organisms encounter while a ship is underway. This study investigated the effect of static and dynamic immersion on the adhesion and settlement of diatoms to one antifouling coating (BRA 640), four fouling-release coatings (Intersleek(®) 700, Intersleek(®) 900, Hempasil X3, and Dow Corning 3140) and one standard surface (Intergard(®) 240 Epoxy). Differences in community composition were observed between the static and dynamic treatments. Achnanthes longipes was present on all coatings under static immersion, but was not present under dynamic immersion. This was also found for diatoms in the genera Bacillaria and Gyrosigma. Melosira moniformis was the only diatom present under dynamic conditions, but not static conditions. Several common fouling diatom genera were present on panels regardless of treatment: Amphora, Cocconeis, Entomoneis Cylindrotheca, Licmophora, Navicula, Nitzschia, Plagiotropis, and Synedra. Biofilm adhesion, diatom abundance and diatom diversity were found to be significantly different between static and dynamic treatments; however, the difference was dependent on coating and sampling date. Several coatings (Epoxy, DC 3140 and IS 700) had significantly higher biofilm adhesion on dynamically treated panels on at least one of the four sampling dates, while all coatings had significantly higher diatom abundance on at least one sampling date. Diversity was significantly greater on static panels than dynamic panels for Epoxy, IS 700 and HX3 at least once during the sampling period. The results demonstrate how hydrodynamic stress will significantly influence the microfouling community. Dynamic immersion testing is required to fully understand how antifouling surfaces will respond to biofilm formation when subjected to the stresses experienced

  13. Graphene-epoxy flexible transparent capacitor obtained by graphene-polymer transfer and UV-induced bonding.

    Science.gov (United States)

    Sangermano, Marco; Chiolerio, Alessandro; Veronese, Giulio Paolo; Ortolani, Luca; Rizzoli, Rita; Mancarella, Fulvio; Morandi, Vittorio

    2014-02-01

    A new approach is reported for the preparation of a graphene-epoxy flexible transparent capacitor obtained by graphene-polymer transfer and UV-induced bonding. SU8 resin is employed for realizing a well-adherent, transparent, and flexible supporting layer. The achieved transparent graphene/SU8 membrane presents two distinct surfaces: one homogeneous conductive surface containing a graphene layer and one dielectric surface typical of the epoxy polymer. Two graphene/SU8 layers are bonded together by using an epoxy photocurable formulation based on epoxy resin. The obtained material showed a stable and clear capacitive behavior. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. A facile dip-coating process for preparing highly durable superhydrophobic surface with multi-scale structures on paint films.

    Science.gov (United States)

    Cui, Zhe; Yin, Long; Wang, Qingjun; Ding, Jianfu; Chen, Qingmin

    2009-09-15

    Superhydrophobic surfaces with multi-scale nano/microstructures have been prepared on epoxy paint surfaces using a feasible dip-coating process. The microstructures with 5-10 microm protuberances were first prepared on epoxy paint surface by sandblast. Then the nanostructures were introduced on the microstructure surface by anchoring 50-100 nm SiO(2) particles (nano-SiO(2)) onto the sandblasted paint surface, which was completed by dip-coating with a nano-SiO(2)/epoxy adhesive solution (M1). At last the surface was further modified for enhancing hydrophobicity by another dip-coating with a solution of a low surface energy polymer, aminopropyl terminated polydimethylsiloxane (ATPS) modified epoxy adhesive (M2). The water contact angle of the as-prepared samples reached as high as 167.8 degrees and the sliding angle was 7 degrees. The prepared superhydrophobic surface exhibited excellent durability to the high speed scouring test and high stability in neutral and basic aqueous solutions and some common organic solvents. In addition, this method can be adopted to fabricate large scale samples with a good homogeneity of the whole surface at very low cost.

  15. Low cycle fatigue behavior of titanium carbide coated molybdenum

    International Nuclear Information System (INIS)

    Nishi, Hiroshi; Oku, Tatsuo; Kodaira, Tsuneo; Kikuyama, Toshihiko

    1985-09-01

    Sintered molybdenum coated by TiC is used for the first wall such as a troidal fixed limiter and a magnetic limiter plate in JT-60, that is being operated at JAERI presently. This report describes the low cycle fatigue behavior of sintered molybdenum and the influence of TiC coating on fatigue strength. The low cycle fatigue test was conducted at room temperature and 500 0 C. The test results was also analyzed by fractographic observation, metallography and element analysis using EPMA. The low cycle fatigue strength of the molybdenum coated by TiC at 500 0 C is decreased compared with the one at room temperature. (author)

  16. Impact behavior of basalt/epoxy composite: Comparison between flat and twill fabric

    Science.gov (United States)

    Papa, I.; Ricciardi, M. R.; Antonucci, V.; Langella, A.; Lopresto, V.

    2018-05-01

    Two types of basalt fibre reinforced epoxy laminates were realized by overlapping flat and twill woven basalt fabrics by resin infusion. Rectangular specimens, cut from the panels were impacted at penetration and at increasing energy values, to investigate the damage onset and propagation. A non-destructive technique, Ultrasound testing (UT), was adopted to investigate the internal damage. Despite the difficulties to obtain information by UT method due to the high amount of signal absorbed, the technique, properly calibrated, proved to be very useful in providing information about the presence, the shape and the extent of the delaminations. The results were compared at the aim to investigate the effect of the fiber architecture (textile). The experimental results indicate a similar impact behavior between basalt flat and twill composites but in the case of the twill a minor delaminated area was detected, even if a higher absorbed energy was recorded

  17. Effects of moisture, elevated temperature, and fatigue loading on the behavior of graphite/epoxy buffer strip panels with center cracks

    Science.gov (United States)

    Bigelow, C. A.

    1988-01-01

    The effects of fatigue loading combined with moisture and heat on the behavior of graphite epoxy panels with either Kevlar-49 or S-glass buffer strips were studied. Buffer strip panels, that had a slit in the center to represent damage, were moisture conditioned or heated, fatigue loaded, and then tested in tension to measure their residual strength. The buffer strips were parallel to the loading direction and were made by replacing narrow strips of the 0 deg graphite plies with Kevlar-49 epoxy or S-glass epoxy on a 1-for-1 basis. The panels were subjected to a fatigue loading spectrum. One group of panels was preconditioned by soaking in 60 C water to produce a 1 percent weight gain then tested at room temperature. One group was heated to 82 C during the fatigue loading. Another group was moisture conditioned and then tested at 82 C. The residual strengths of the buffer panels were not highly affected by the fatigue loading, the number of repetitions of the loading spectrum, or the maximum strain level. The moisture conditioning reduced the residual strengths of the S-glass buffer strip panel by 10 to 15 percent below the ambient results. The moisture conditioning did not have a large effect on the Kevlar-49 panels.

  18. Propriedades Mecânicas de Epóxis Utilizadas no Recobrimento Interno de Oleodutos e Gasodutos Mechanical Properties of Epoxy for Internal Coatings of Pipelines

    Directory of Open Access Journals (Sweden)

    Marysilvia Ferreira

    2002-01-01

    Full Text Available Propriedades mecânicas de recobrimentos a base de epóxi para aplicação in situ em dutos de transporte na indústria petrolífera foram avaliadas. Os recobrimentos foram aplicados sobre substratos de aço carbono submetidos a dois diferentes padrões de tratamento superficial (ST3 e SA2½ e avaliou-se a influência do mesmo em propriedades tais como adesão, impacto, dureza e desgaste do material. Observou-se que a falha de adesão ocorre por diferentes mecanismos dependendo do material do recobrimento e da preparação da superfície. Desgaste ocorre basicamente por mecanismo abrasivo embora se tenha observado desgaste adesivo significativo em alguns casos, dependendo do material e do padrão de tratamento da superfície. Resultados de microdureza indicaram, como esperado, ser esta uma propriedade inerente ao material, não sendo afetada pelo padrão de limpeza da superfícieMechanical properties of epoxy based coating materials suitable for in-situ internal application in gas/oil pipelines were studied. Coatings were applied on carbon steel substrates submitted to two different surface preparation procedures (ST3 and SA2½ and the effect from surface treatment on coating adhesion, impact, hardness and wear was evaluated. It was found that adhesion failure occurs through distinct mechanisms depending on coating material and surface preparation. Wear occurs mostly by abrasive mechanism, although adhesive wear was found to be significant in some cases also depending on material and surface. Microhardness, as expected, was found to be a coating property not unaffected by surface treatment.

  19. Adhesive strength of hydroxyl apatite(HA coating and biomechanics behavior of HA-coated prosthesis:an experimental study

    Directory of Open Access Journals (Sweden)

    Tian-yang ZHANG

    2011-05-01

    Full Text Available Objective To explore the influence of adhesive strength of hydroxyapatite(HA coating on the post-implantation stability of HA-coated prosthesis.Methods The adhesive strength and biomechanics behavior of HA coating were studied by histopathological observation,material parameters and biomechanical testing,the titanium(Ti-coated prosthesis was employed as control.Results Scratch test showed that the adhesive strength of HA coating was significantly lower than that of Ti coating(P < 0.01.Histopathological examination and bone morphometry showed that,at the early stage of prosthesis implantation,the bony growth around HA-coated prosthesis was significantly higher than that around Ti-coated prosthesis(P < 0.01,but the ultimate shear strength of HA-coated prosthesis was much lower than that of Ti-coated prosthesis(P < 0.01.After the push-out test with prosthesis,histopathological observation showed that there were accumulations of clump-and strip-like granular residues on the surface of bones that newly grew around the HA-coated prosthesis,and surface energy-dispersive X-ray spectroscopy(EDX analysis also confirmed that the shear stress induced HA decohesion from the substrate of prosthesis.Conclusions Although HA coating showed a satisfactory effect on early bone formation and prosthetic stability,due to the deficiencies of adhesive strength,the early stability of prosthesis may be gradually destroyed by the shear loads of human body and coating degradation.

  20. Corrosion behavior of zinc-nickel alloy electrodeposited coatings

    Energy Technology Data Exchange (ETDEWEB)

    Fabri Miranda, F.J. [USIMINAS, Ipatinga, Minas Gerais (Brazil); Margarit, I.C.P.; Mattos, O.R.; Barcia, O.E. [UFRJ, Rio de Janeiro (Brazil); Wiart, R. [Univ. Pierre et M. Curie, Paris (France)

    1999-08-01

    Various types of zinc-electrocoated steel sheets are used to improve the durability of car bodies. Among these coatings, the Zn-Ni alloy has higher corrosion resistance than pure Zn, as well as better welding and painting properties. The corrosion mechanism of the Zn-Ni alloy has been investigated mainly on the basis of accelerated tests and electrochemical measurements. There are few data about long-term corrosion tests. In the present study, the behavior of unpainted Zn-Ni alloy coated steel was studied during 3 years of exposure in industrial and marine environments. Electrochemical impedance spectroscopy (EIS) and surface analysis (scanning electron microscopy [SEM] and Auger electron spectroscopy [AES]) were the experimental techniques used. Long-term atmospheric corrosion mechanism of Zn-Ni coatings was discussed and compared with that proposed based on short-term tests.

  1. Fluidization bed coating of copper bars with epoxy powder

    OpenAIRE

    Soh, Chiaw Min

    2014-01-01

    Fluidized bed coating (FBC) is a process where preheated material is dipped into a flowing liquid bed of powder. Although FBC has existed for more than half a century, however there is little knowledge about the fluidized bed design that gives excellent fluidization quality as well as reducing powder entrainment. The objectives of this thesis are to investigate the effect of two different types of distributor with different pressure drop on powder coating, hydrodynamics of fluidized bed coati...

  2. Influence of elastomeric seal plate surface chemistry on interface integrity in biofouling-prone systems: Evaluation of a hydrophobic "easy-release" silicone-epoxy coating for maintaining water seal integrity of a sliding neoprene/steel interface

    Science.gov (United States)

    Andolina, Vincent L.

    The scientific hypothesis of this work is that modulation of the properties of hard materials to exhibit abrasion-reducing and low-energy surfaces will extend the functional lifetimes of elastomeric seals pressed against them in abrasive underwater systems. The initial motivation of this work was to correct a problem noted in the leaking of seals at major hydropower generating facilities subject to fouling by abrasive zebra mussel shells and extensive corrosion. Similar biofouling-influenced problems can develop at seals in medical devices and appliances from regulators in anesthetic machines and SCUBA diving oxygen supply units to autoclave door seals, injection syringe gaskets, medical pumps, drug delivery components, and feeding devices, as well as in food handling equipment like pasteurizers and transfer lines. Maritime and many other heavy industrial seal interfaces could also benefit from this coating system. Little prior work has been done to elucidate the relationship of seal plate surface properties to the friction and wear of elastomeric seals during sliding contacts of these articulating materials, or to examine the secondary influence of mineralized debris within the contacting interfaces. This investigation utilized the seal materials relevant to the hydropower application---neoprene elastomer against carbon steel---with and without the application of a silicone-epoxy coating (WearlonRTM 2020.98) selected for its wear-resistance, hydrophobicity, and "easy-release" capabilities against biological fouling debris present in actual field use. Analytical techniques applied to these materials before and after wear-producing processes included comprehensive Contact Angle measurements for Critical Surface Tension (CA-CST) determination, Scanning Electron Microscopic inspections, together with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and X-Ray Fluorescence (XRF) measurements for determination of surface texture and inorganic composition, Multiple

  3. Improvement of Mechanical and Dielectric Properties of Epoxy Resin Using CNTs/ZnO Nanocomposite.

    Science.gov (United States)

    Vu, Pham Gia; Truc, Trinh Anh; Chinh, Nguyen Thuy; Tham, Do Quang; Trung, Tran Huu; Oanh, Vu Ke; Hang, To Thi Xuan; Olivier, Marjorie; Hoang, Thai

    2018-04-01

    In this study, carbon nanotubes (CNTs)/ZnO composites had been prepared using the sol-gel method and then incorporated into an epoxy resin for reinforcement of mechanical and electrical properties. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) Field Emission Scanning Electron Microscope (FE-SEM) analyses show that the ZnO nanoparticles deposited on CNTs were crystallized in a hexagonal wurtzite structure. Average particle size of ZnO deposited on the CNT was about 8 nm. The mechanical and dielectric properties of epoxy containing CNTs/ZnO were investigated in comparison to epoxy resin and epoxy resin containing only CNT or ZnO nanoparticles. The results indicated that tensile strength and elongation at break of the nanocomposite were substantially improved with the presence of CNTs/ZnO at the equal volume. The DSC analysis associate with the dielectric results shows that the behavior of epoxy/CNTs/ZnO is identical to epoxy/ZnO composite, and the CNTs is essential to the distributed arrangement of ZnO in the epoxy resin.

  4. A strategy for prediction of the elastic properties of epoxy-cellulose nanocrystal-reinforced fiber networks

    Science.gov (United States)

    Johnathan E. Goodsell; Robert J. Moon; Alionso Huizar; R. Byron Pipes

    2014-01-01

    The reinforcement potential of cellulose nanocrystal (CNC) additions on an idealized 2-dirmensional (2-D) fiber network structure consisting of micron sized fiber elements was investigated. The reinforcement mechanism considered in this study was through the stiffening of the micron sized fiber elements via a CNC-epoxy coating. A hierarchical analytical modeling...

  5. Crystallization and deuterium permeation behaviors of yttrium oxide coating prepared by metal organic decomposition

    Directory of Open Access Journals (Sweden)

    Takumi Chikada

    2016-12-01

    Full Text Available Yttrium oxide coatings were fabricated on reduced activation ferritic/martensitic steels by metal organic decomposition with a dip-coating technique, and their deuterium permeation behaviors were investigated. The microstructure of the coatings varied with heat-treatment temperature: amorphous at 670ºC (amorphous coating and crystallized at 700ºC (crystallized coating. Deuterium permeation flux of the amorphous coating was lower than the uncoated steel by a factor of 5 at 500ºC, while that of the crystallized coating was lower by a factor of around 100 at 400‒550ºC. The permeation fluxes of both coatings were drastically decreased during the measurements at higher temperatures by a factor of up to 790 for the amorphous coating and 1000 for the crystallized one, indicating a microstructure modification occurred by an effect of test temperature with hydrogen flux. Temperature dependence of deuterium diffusivity in the coatings suggests that the decrease of the permeation flux has been derived from a decrease of the diffusivity. Characteristic permeation behaviors were observed with different annealing conditions; however, they can be interpreted using the permeation mechanism clarified in the previous erbium oxide coating studies.

  6. Scratch Behaviors of Cr-Coated Zr-Based Fuel Claddings for Accident-Tolerant Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Ho; Kim, Il-Hyun; Kim, Hyun-Gil; Kim, Hyung-Kyu; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    As the progression of Fukushima accident is worsened by the runaway reaction at a high temperature above 1200 .deg. C, it is essential to ensure the stabilities of coating layers on conventional Zr-based alloys during normal operations as well as severe accident conditions. This is because the failures of coating layer result in galvanic corrosion phenomenon by potential difference between coating layer and Zr alloy. Also, it is possible to damage the coating layer during handling and manufacturing process by contacting structural components of a fuel assembly. So, adhesion strength is one of the key factors determining the reliability of the coating layer on conventional Zr-based alloy. In this study, two kinds of Cr-coated Zr-based claddings were prepared using arc ion plating (AIP) and direct laser (DL) coating methods. The objective is to evaluate the scratch deformation behaviors of each coating layers on Zr alloys. Large area spallation below normal load of about 15 N appeared to be the predominant mode of failure in the AIP coating during scratch test. However, no tensile crack were found in entire stroke length. In DL coating, small plastic deformation and grooving behavior are more dominant scratching results. It was observed that the change of the slope of the COF curve did not coincide with the failure of coating layer.

  7. Thickness dependence of the poling and current-voltage characteristics of paint films made up of lead zirconate titanate ceramic powder and epoxy resin

    Science.gov (United States)

    Egusa, Shigenori; Iwasawa, Naozumi

    1995-11-01

    A specially prepared paint made up of lead zirconate titanate (PZT) ceramic powder and epoxy resin was coated on an aluminum plate and was cured at room temperature, thus forming the paint film of 25-300 μm thickness with a PZT volume fraction of 53%. The paint film was then poled at room temperature, and the poling behavior was determined by measuring the piezoelectric activity as a function of poling field. The poling behavior shows that the piezoelectric activity obtained at a given poling field increases with an increase in the film thickness from 25 to 300 μm. The current-voltage characteristic of the paint film, on the other hand, shows that the increase in the film thickness leads not only to an increase in the magnitude of the current density at a given electric field but also to an increase in the critical electric field at which the transition from the ohmic to space-charge-limited conduction takes place. This fact indicates that the amount of the space charge of electrons injected into the paint film decreases as the film thickness increases. Furthermore, comparison of the current-voltage characteristic of the paint film with that of a pure epoxy film reveals that the space charge is accumulated largely at the interface between the PZT and epoxy phases in the paint film. On the basis of this finding, a model is developed for the poling behavior of the paint film by taking into account a possible effect of the space-charge accumulation and a broad distribution of the electric field in the PZT phase. This model is shown to give an excellent fit to the experimental data of the piezoelectric activity obtained here as a function of poling field and film thickness.

  8. Three-Dimensional Graphene Foam Induces Multifunctionality in Epoxy Nanocomposites by Simultaneous Improvement in Mechanical, Thermal, and Electrical Properties.

    Science.gov (United States)

    Embrey, Leslie; Nautiyal, Pranjal; Loganathan, Archana; Idowu, Adeyinka; Boesl, Benjamin; Agarwal, Arvind

    2017-11-15

    Three-dimensional (3D) macroporous graphene foam based multifunctional epoxy composites are developed in this study. Facile dip-coating and mold-casting techniques are employed to engineer microstructures with tailorable thermal, mechanical, and electrical properties. These processing techniques allow capillarity-induced equilibrium filling of graphene foam branches, creating epoxy/graphene interfaces with minimal separation. Addition of 2 wt % graphene foam enhances the glass transition temperature of epoxy from 106 to 162 °C, improving the thermal stability of the polymer composite. Graphene foam aids in load-bearing, increasing the ultimate tensile strength by 12% by merely 0.13 wt % graphene foam in an epoxy matrix. Digital image correlation (DIC) analysis revealed that the graphene foam cells restrict and confine the deformation of the polymer matrix, thereby enhancing the load-bearing capability of the composite. Addition of 0.6 wt % graphene foam also enhances the flexural strength of the pure epoxy by 10%. A 3D network of graphene branches is found to suppress and deflect the cracks, arresting mechanical failure. Dynamic mechanical analysis (DMA) of the composites demonstrated their vibration damping capability, as the loss tangent (tan δ) jumps from 0.1 for the pure epoxy to 0.24 for ∼2 wt % graphene foam-epoxy composite. Graphene foam branches also provide seamless pathways for electron transfer, which induces electrical conductivity exceeding 450 S/m in an otherwise insulator epoxy matrix. The epoxy-graphene foam composite exhibits a gauge factor as high as 4.1, which is twice the typical gauge factor for the most common metals. Simultaneous improvement in thermal, mechanical, and electrical properties of epoxy due to 3D graphene foam makes epoxy-graphene foam composite a promising lightweight and multifunctional material for aiding load-bearing, electrical transport, and motion sensing in aerospace, automotive, robotics, and smart device structures.

  9. Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

    Energy Technology Data Exchange (ETDEWEB)

    Amir, N., E-mail: norlailiamir@petronas.com.my; Othman, W. M. S. W., E-mail: wamosa@gmail.com; Ahmad, F., E-mail: faizahmad@petronas.com.my [Mechanical Engineering Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

  10. Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

    International Nuclear Information System (INIS)

    Amir, N.; Othman, W. M. S. W.; Ahmad, F.

    2015-01-01

    This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating

  11. Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

    Science.gov (United States)

    Amir, N.; Othman, W. M. S. W.; Ahmad, F.

    2015-07-01

    This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

  12. Interactions between the glass fiber coating and oxidized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ku-Herrera, J.J., E-mail: jesuskuh@live.com.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Nistal, A. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Cauich-Rodríguez, J.V. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Rubio, F.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Bartolo-Pérez, P. [Departamento de Física Aplicada, Cinvestav, Unidad Mérida, C.P., 97310 Mérida, Yucatán (Mexico)

    2015-03-01

    Graphical abstract: - Highlights: • Oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto E-glass fibers. • The role of the fiber coating on the deposition of MWCNTs on the fibers is studied. • A rather homogeneous deposition of MWCNTs is achieved if the coating is maintained. • Multiple oxygen-containing groups were found in the analysis of the fiber coating. • Evidence of chemical interaction between MWCNTs and the fiber coating was found. - Abstract: Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as “sizing”), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

  13. Interactions between the glass fiber coating and oxidized carbon nanotubes

    International Nuclear Information System (INIS)

    Ku-Herrera, J.J.; Avilés, F.; Nistal, A.; Cauich-Rodríguez, J.V.; Rubio, F.; Rubio, J.; Bartolo-Pérez, P.

    2015-01-01

    Graphical abstract: - Highlights: • Oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto E-glass fibers. • The role of the fiber coating on the deposition of MWCNTs on the fibers is studied. • A rather homogeneous deposition of MWCNTs is achieved if the coating is maintained. • Multiple oxygen-containing groups were found in the analysis of the fiber coating. • Evidence of chemical interaction between MWCNTs and the fiber coating was found. - Abstract: Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as “sizing”), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible

  14. Structural Analysis of Polyhedral Oligomeric Silsesquioxane Coated SiC Nanoparticles and Their Applications in Thermoset Polymers

    International Nuclear Information System (INIS)

    Reza-E-Rabby, M.; Jeelani, Sh.; Rangari, V. K.

    2015-01-01

    The SiC nanoparticles (NPs) were sonochemically coated with Octa Isobutyl (OI) polyhedral oligomeric silsesquioxane (POSS) to create a compatible interface between particle and thermoset polymer. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques were used to analyze the structure of OI-POSS coated SiC nanoparticles. These results revealed the formation of a covalent bonding between SiC and OI-POSS. The transmission electron microscopy (TEM) analysis of OI-POSS coated SiC nanoparticles has also shown the indication of attachment between these two nanoparticles. The OI-POSS coated SiC nanoparticles were further reinforced into a thermoset resin system in order to evaluate mechanical and thermal properties of nano composites. The flexural strength, modulus, and glass transition temperature were found to be enhanced while SiC and OI-POSS coated SiC were infused into epoxy system compared to those properties of neat epoxy resin

  15. Structural Analysis of Polyhedral Oligomeric Silsesquioxane Coated SiC Nanoparticles and Their Applications in Thermoset Polymers

    Directory of Open Access Journals (Sweden)

    Md. Reza-E-Rabby

    2015-01-01

    Full Text Available The SiC nanoparticles (NPs were sonochemically coated with OctaIsobutyl (OI polyhedral oligomeric silsesquioxane (POSS to create a compatible interface between particle and thermoset polymer. X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FTIR, and X-ray diffraction (XRD techniques were used to analyze the structure of OI-POSS coated SiC nanoparticles. These results revealed the formation of a covalent bonding between SiC and OI-POSS. The transmission electron microscopy (TEM analysis of OI-POSS coated SiC nanoparticles has also shown the indication of attachment between these two nanoparticles. The OI-POSS coated SiC nanoparticles were further reinforced into a thermoset resin system in order to evaluate mechanical and thermal properties of nanocomposites. The flexural strength, modulus, and glass transition temperature were found to be enhanced while SiC and OI-POSS coated SiC were infused into epoxy system compared to those properties of neat epoxy resin.

  16. Enhancing Mechanical and Thermal Properties of Epoxy Nanocomposites via Alignment of Magnetized SiC Whiskers.

    Science.gov (United States)

    Townsend, James; Burtovyy, Ruslan; Aprelev, Pavel; Kornev, Konstantin G; Luzinov, Igor

    2017-07-12

    This research is focused on the fabrication and properties of epoxy nanocomposites containing magnetized SiC whiskers (MSiCWs). To this end, we report an original strategy for fabrication of magnetically active SiCWs by decorating the whiskers with magnetic (iron oxide) nanoparticles via polymer-polymer (poly(acrylic acid)/poly(2-vinyl pyridine)) complexation. The obtained whiskers demonstrated a substantial magnetic response in the polymerizing epoxy resin, with application of only a 20 mT (200 G) magnetic field. We also found that the whiskers chemically reacted with the epoxy resin, causing formation of an extended interphase near the boundary of the whiskers. The SiC whiskers oriented with the magnetic field demonstrated positive effects on the behavior of epoxy-based nanocomposites. Namely, the aligned MSiCWs enhanced the thermomechanical properties of the materials significantly above that of the neat epoxy and epoxy nanocomposite, with randomly oriented whiskers.

  17. Thermal expansion of epoxy-fiberglass composite specimens

    International Nuclear Information System (INIS)

    McElroy, D.L.; Weaver, F.J.; Bridgman, C.

    1986-01-01

    The thermal expansion behavior of three epoxy-fiberglass composite specimens was measured from 20 to 120 0 C (70 to 250 0 F) using a fused quartz push-rod dilatometer. Billets produced by vacuum impregnating layers of two types of fiberglass cloth with an epoxy resin were core-drilled to produce cylindrical specimens. These were used to study expansion perpendicular and parallel to the fiberglass layers. The dilatometer is held at a preselected temperature until steady-state is indicated by stable length and temperature data. Before testing the composite specimens, a reliability check of the dilatometer was performed using a copper secondary standard. This indicated thermal expansion coefficient (α) values within +-2% of expected values from 20 to 200 0 C

  18. Fracture and flaking off behavior of coated layer of DyBCO coated conductor under applied tensile strain

    International Nuclear Information System (INIS)

    Arai, T.; Shin, J.K.; Matsubayashi, H.; Ochiai, S.; Okuda, H.; Osamura, K.; Prusseit, W.

    2009-01-01

    The tensile behavior of the DyBa 2 Cu 3 O 7-δ (DyBCO) coated conductor with MgO buffer layer deposited on the Hastelloy C-276 substrate by inclined substrate deposition (ISD) was studied. The tensile stress-strain curve showed a flat region, characterized by the discontinuous yielding of the substrate due to the Lueders band extension from the gripped portions of the sample. In the area where the Lueders band had passed, the coating layer showed severe multiple transverse cracking due to the localized plastic deformation of the substrate. The flaking off of the coating layers took place at high applied strain, due to the buckling fracture of the coated layers in the sample width direction, accompanied by the interfacial debonding.

  19. Effects of alumina nanoparticles on dynamic impact responses of carbon fiber reinforced epoxy matrix nanocomposites

    OpenAIRE

    Halil B. Kaybal; Hasan Ulus; Okan Demir; Ömer S. Şahin; Ahmet Avcı

    2018-01-01

    The influence of alumina (Al2O3) nanoparticles addition upon low-velocity impact behaviors of carbon fiber (CF) reinforced laminated epoxy nanocomposites have been investigated. For this purpose, different amounts of Al2O3 nanoparticles ranging from 1 to 5 wt% were added to the epoxy resin in order to observe the effect of nanoparticle loadings. CF reinforced epoxy based laminated nanocomposites were produced using Vacuum Assisted Resin Infusion Method (VARIM). The low velocity impact (LVI) t...

  20. Indentation creep behavior of cold sprayed aluminum amorphous/nano-crystalline coatings

    Energy Technology Data Exchange (ETDEWEB)

    Babu, P. Suresh [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Hyderabad 500005, Andhra Pradesh (India); Nanomechanics and Nanotribology Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Jha, R.; Guzman, M. [Nanomechanics and Nanotribology Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Sundararajan, G. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Hyderabad 500005, Andhra Pradesh (India); Agarwal, Arvind, E-mail: agarwala@fiu.edu [Nanomechanics and Nanotribology Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States)

    2016-03-21

    In this study, we report room temperature creep properties of cold sprayed aluminum amorphous/nanocrystalline coating using nanoindentation technique. Creep experiments were also performed on heat treated coatings to study the structural stability and its influence on the creep behavior. The peak load and holding time were varied from 1000 to 4000 µN and 0 to 240 s respectively. Stress exponent value (n) vary from 5.6 to 2.3 in as-sprayed (AS) coatings and 7.2–4.8 in heat treated (HT) coatings at peak load of 1000–4000 µN at 240 s hold time. Higher stress exponent value indicates heat treated coatings have more resistance to creep deformation than as-sprayed coatings. Relaxed, partially crystallized structure with less porosity, and stronger inter-splat boundaries restrict the deformation in heat treated coatings as compared to greater free volume generation in amorphous as-sprayed coatings. The computed activation volume of heat treated coatings is twice of as-sprayed coatings indicating greater number of atom participation in shear band formation in heat treated coatings. The proposed mechanism was found to be consistent with the stress exponent values.

  1. Thermal fatigue behavior of thermal barrier coatings by air plasma spray

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Sang; Kim, Eui Hyun [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Lee, Jung Hyuk [Korea Plant Service and Engineering Co. Ltd., Incheon (Korea, Republic of)

    2008-06-15

    Effects of top coat morphology and thickness on thermal fatigue behavior of Thermal Barrier Coatings (TBC) were investigated in this study. Thermal fatigue tests were conducted on three coating specimens with different top coat morphology and thickness, and then the test data were compared via microstructures, cycles to failure, and fracture surfaces. In the air plasma spray specimens (APS1, APS2), top coat were 200 and 300 {mu}m respectively. The thickness of top coat was about 700 {mu}m in the Perpendicular Cracked Specimen (PCS). Under thermal fatigue condition at 1,100 .deg. C, the cycles to top coat failure of APS1, APS2, and PCS were 350, 560 and 480 cycles, respectively. The cracks were initiated at the interface of top coat and Thermally Grown Oxide (TGO) and propagated into TGO or top coat as the number of thermal fatigue cycles increased. For the PCS specimen, additive cracks were initiated and propagated at the starting points of perpendicular cracks in the top coat. Also, the thickness of TGO and the decrease of aluminium concentration in bond coat do not affect the cycles to failure.

  2. Preparation, Characterization, and Modeling of Carbon Nanofiber/Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Lan-Hui Sun

    2011-01-01

    Full Text Available There is a lack of systematic investigations on both mechanical and electrical properties of carbon nanofiber (CNF-reinforced epoxy matrix nanocomposites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nanocomposites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nanocomposites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nanocomposite with a 1.0 wt% CNFs. The alternate-current (AC electrical properties of the CNF/epoxy nanocomposites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt% (0.058 vol% CNFs and by ten orders of magnitude for nanocomposites with CNF volume fractions higher than 1.0 wt% (0.578 vol%. The percolation threshold (i.e., the critical CNF volume fraction is found to be at 0.057 vol%.

  3. Effect of Graphene Oxide Mixed Epoxy on Mechanical Properties of Carbon Fiber/Acrylonitrile-Butadiene-Styrene Composites.

    Science.gov (United States)

    Wang, Cuicui; Ge, Heyi; Ma, Xiaolong; Liu, Zhifang; Wang, Ting; Zhang, Jingyi

    2018-04-01

    In this study, the watersoluble epoxy resin was prepared via the ring-opening reaction between diethanolamine and epoxy resin. The modified resin mixed with graphene oxide (GO) as a sizing agent was coated onto carbon fiber (CF) and then the GO-CF reinforced acrylonitrile-butadienestyrene (ABS) composites were prepared. The influences of the different contents of GO on CF and CF/ABS composite were explored. The combination among epoxy, GO sheets and maleic anhydride grafted ABS (ABSMA) showed a synergistic effect on improving the properties of GO-CF and GO-CF/ABS composite. The GO-CF had higher single tensile strength than the commercial CF. The maximum ILSS of GO-CF/ABS composite obtained 19.2% improvement as compared with that of the commercial CF/ABS composite. Such multiscale enhancement method and the synergistic reinforced GO-CF/ABS composite show good prospective applications in many industry areas.

  4. Bacterial colonization on coated and uncoated orthodontic wires: A prospective clinical trial.

    Science.gov (United States)

    Raji, Seyed Hamid; Shojaei, Hasan; Ghorani, Parinaz Saeidi; Rafiei, Elahe

    2014-11-01

    The advantages of coated orthodontic wires such as esthetic and their effects on reduced friction, corrosion and allergic reaction and the significant consequences of plaque accumulation on oral health encouraged us to assess bacterial colonization on these wires. A total of 18 (9 upper and 9 lower) epoxy resin coated 16 × 22 nickel-titanium wires (Spectra, GAC, USA) and 18 (9 upper and 9 lower) non-coated 16 × 22 nickel-titanium wires (Sentalloy, GAC, USA) with isolated packages were selected and sterilized before application. The samples were divided randomly between upper and lower arches in 18 patients and hence that every patient received one coated and one uncoated wire at the same time. Samples were removed and cut in equal lengths after 3 weeks and placed in phosphate buffered saline buffer. After separation of bacteria in trypsin and ethylenediaminetetraacetic acid solution, the diluted solution was cultured in blood agar and bacterial colony forming units were counted. Finally, the data was analyzed using the paired t-test and the significance was set at 0.05. Mean of bacterial colonization on uncoated wires was more than that of coated wires (P < 0.001). Bacterial plaque accumulation on epoxy resin coated nickel-titanium orthodontic wires is significantly lower than uncoated nickel-titanium wires.

  5. Improvement in electrical, thermal and mechanical properties of epoxy by filling carbon nanotube

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CNTs reinforced Epon 862 epoxy have been evaluated. Firstly, 0.1, 0.2, 0.3, and 0.4 wt% CNT were infused into epoxy through a high intensity ultrasonic liquid processor and then mixed with EpiCure curing agent W using a high speed mechanical agitator. Electric conductivity, dynamic mechanical analysis (DMA, three point bending tests and fracture tests were then performed on unfilled, CNT-filled epoxy to identify the loading effect on the properties of materials. Experimental results show significant improvement in electric conductivity. The resistivity of epoxy decreased from 1014 Ω•m of neat epoxy to 10 Ω•m with 0.4% CNT. The experimental results also indicate that the frequency dependent behavior of CNT/epoxy nanocomposite can be modeled by R-C circuit, permittivity of material increase with increasing of CNT content. DMA studies revealed that filling the carbon nanotube into epoxy can produce a 90% enhancement in storage modulus and a 17°C increase in Tg. Mechanical test results showed that modulus increased with higher CNT loading percentages, but the 0.3 wt% CNT-infusion system showed the maximum strength and fracture toughness enhancement. The decrease in strength and fracture toughness in 0.4% CNT/epoxy was attributed to poor dispersions of nanotubes in the composite.

  6. Enhanced microwave absorption property of epoxy nanocomposites based on PANI@Fe3O4@CNFs nanoparticles with three-phase heterostructure

    Science.gov (United States)

    Yang, Lingfeng; Cai, Haopeng; Zhang, Bin; Huo, Siqi; Chen, Xi

    2018-02-01

    Novel electromagnetic functionalized carbon nanofibers (CNFs) have been synthesized by coating with Fe3O4 magnetite nanoparticles and conducting polymers polyaniline (PANI) on CNFs through a layer by layer assembly. The Fe3O4@CNFs were first prepared by coating nano-Fe3O4 particles on CNFs via co-precipitation method; Then the PANI was coated on Fe3O4@CNFs using an in situ polymerization process to obtain PANI@Fe3O4@CNFs nanoparticles. The prepared PANI@Fe3O4@CNFs nanoparticles were dispersed in the epoxy matrix to fabricate microwave absorbing nanocomposites. Compared with the Fe3O4@CNFs/epoxy nanocomposites, the PANI@Fe3O4@CNFs/epoxy nanocomposites exhibit better microwave absorbing properties. The composite containing 15 wt% of PANI@Fe3O4@CNFs with the thickness of 2 mm showed a minimum reflection loss (RL) value of -23.7 dB with an effective absorption bandwidth which is about 3.7 GHz (11.9-15.6 GHz) in the frequency range of 1-18 GHz, indicating that it is an attractive candidate for efficient microwave absorber. A potential absorption mechanism was proposed for enhancement of the impedance-matching condition and electromagnetic wave-attenuation characteristic of materials. Specifically, the impedance-matching condition was improved by the combination of conductive polymers and magnetic nanoparticles with CNFs. The electromagnetic wave attenuation characteristic was enhanced by multiple reflections, due to the increased propagation paths.

  7. Structural and functional characterization of barium zirconium titanate / epoxy composites

    Directory of Open Access Journals (Sweden)

    Filiberto González Garcia

    2011-12-01

    Full Text Available The dielectric behavior of composite materials (barium zirconium titanate / epoxy system was analyzed as a function of ceramic concentration. Structure and morphologic behavior of the composites was investigated by X-ray Diffraction (XRD, Fourier transformed infrared spectroscopy (FT-IR, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM and transmission electron microscopy (TEM analyses. Composites were prepared by mixing the components and pouring them into suitable moulds. It was demonstrated that the amount of inorganic phase affects the morphology of the presented composites. XRD revealed the presence of a single phase while Raman scattering confirmed structural transitions as a function of ceramic concentration. Changes in the ceramic concentration affected Raman modes and the distribution of particles along into in epoxy matrix. Dielectric permittivity and dielectric losses were influenced by filler concentration.

  8. High T{sub g} and fast curing epoxy-based anisotropic conductive paste for electronic packaging

    Energy Technology Data Exchange (ETDEWEB)

    Keeratitham, Waralee, E-mail: waralee.ke@student.chula.ac.th; Somwangthanaroj, Anongnat, E-mail: anongnat.s@chula.ac.th [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330 (Thailand)

    2016-03-09

    Herein, our main objective is to prepare the fast curing epoxy system with high glass transition temperature (T{sub g}) by incorporating the multifunctional epoxy resin into the mixture of diglycidyl ether of bisphenol A (DGEBA) as a major epoxy component and aromatic diamine as a hardener. Furthermore, the curing behavior as well as thermal and thermomechanical properties were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA). It was found that T{sub g} obtained from tan δ of DGEBA/aromatic diamine system increased from 100 °C to 205 °C with the presence of 30 percentage by weight of multifunctional epoxy resin. Additionally, the isothermal DSC results showed that the multifunctional epoxy resin can accelerate the curing reaction of DGEBA/aromatic diamine system. Namely, a high degree of curing (∼90%) was achieved after a few minutes of curing at low temperature of 130 °C, owing to a large number of epoxy ring of multifunctional epoxy resin towards the active hydrogen atoms of aromatic diamine.

  9. Quantitative Mapping of Mechanisms for Photoinitiated Coating Degradation

    DEFF Research Database (Denmark)

    Kiil, Søren

    2015-01-01

    be used toimplement the various effects of water on the degradation mechanisms of cross-linked coatings is also presented and experiments to test the approach are suggested. Additionally, simulations with an existing degradation model for an epoxy–amine coating are used to map the influence of model......This work concerns the mathematical modeling of photoinitiated coating degradation. Using experimental evidence available, some of the most importantassumptions underlying existing models for the rmoset coatings are analyzed and suggestions for further work provided. A modeling approach that can...... parameters on the lag time (i.e., the time passing prior to the onset of erosion) and the stable erosion rate. The simulation results can be used in the optimization of UV radiation-induced intercoat adhesion losses, which are often observed in multilayer coating systems based on top coated epoxy coatings...

  10. Crack propagation behavior of TiN coatings by laser thermal shock experiments

    International Nuclear Information System (INIS)

    Choi, Youngkue; Jeon, Seol; Jeon, Min-seok; Shin, Hyun-Gyoo; Chun, Ho Hwan; Lee, Youn-seoung; Lee, Heesoo

    2012-01-01

    Highlights: ► The crack propagation behavior of TiN coating after laser thermal shock experiment was observed by using FIB and TEM. ► Intercolumnar cracks between TiN columnar grains were predominant cracking mode after laser thermal shock. ► Cracks were propagated from the coating surface to the substrate at low laser pulse energy and cracks were originated at coating-substrate interface at high laser pulse energy. ► The cracks from the interface spread out transversely through the weak region of the columnar grains by repetitive laser shock. - Abstract: The crack propagation behavior of TiN coatings, deposited onto 304 stainless steel substrates by arc ion plating technique, related to a laser thermal shock experiment has been investigated using focused ion beam (FIB) and transmission electron microscopy (TEM). The ablated regions of TiN coatings by laser ablation system have been investigated under various conditions of pulse energies and number of laser pulses. The intercolumnar cracks were predominant cracking mode following laser thermal shock tests and the cracks initiated at coating surface and propagated in a direction perpendicular to the substrate under low loads conditions. Over and above those cracks, the cracks originated from coating-substrate interface began to appear with increasing laser pulse energy. The cracks from the interface also spread out transversely through the weak region of the columnar grains by repetitive laser shock.

  11. Effect of Mixing Condition on Rheological Behavior of Epoxy-Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Gholamhossein Sodeifian

    2012-12-01

    Full Text Available The effect of mixing on rheological behavior of 6% wt epoxy-clay nanocomposites was studied. The mixing processes were carried out by low shear mixer, homogenizer and ultrasonic and combination of different mixing techniques at medium and maximum power. All these methods led to intercalated structure. The XRD results showed that the ultrasonic has the best effect on dispersion while a low shear mixer has the least positive effect. Opposite to an ultrasonic mixing method, the homogenization process through maximum power does not change the dispersion state significantly. The best condition would be to use an ultrasonic mixer after a homogenizer, otherwise the reverse process may result in lower dispersion. Small amplitude oscillatory measurements were carried out on linear regime over 0.1-100 Hz. According to the fact that rheological responses are very sensitive to polymerparticle interactions and accessible surface area, the slope of storage modulus and shear thinning exponent of viscosity are proportional to the level of dispersion. This implies that more increases in intergallary height may lead to less terminal slope. The continuous relaxation profile and zero shear viscosity were generated by experimental data via computer software based on neural network approach. To check the validity of software, the experimental data were recovered with very low deviation using relaxation spectrum. The experimental observations showed that a solid-like behavior, as a result of better dispersion, can prevent the profile from falling especially at longertimes.

  12. Effect of Alkyl Phenol from Cashew Nutshell Liquid on Mechanical and Dry Sliding Wear Behavior of Epoxy Resin

    Directory of Open Access Journals (Sweden)

    Rajesh Panda

    2015-05-01

    Full Text Available A phenalkamine made from the reaction of alkyl phenol from cashew nutshell liquid (CSNL and polyamine was added at three different weight percentages (30%, 40%, and 50% as a diglycidyl ether of bisphenol A (DGEBA epoxy hardener. This curing agent was compared to a traditional polyamine epoxy hardener. It was observed that an increase in phenalkamine concentration resulted in considerable improvement to impact strength and elongation, which ultimately translated to better wear resistance of the cured epoxy compound. Lancaster–Ratner correlations between mechanical and wear resistance properties were found to be linear. Optical microscope observations were used to understand the wear mechanisms of the cured epoxy materials.

  13. Modification of the Interfacial Interaction between Carbon Fiber and Epoxy with Carbon Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Kejing Yu

    2016-05-01

    Full Text Available The mechanical properties of the hybrid materials and epoxy and carbon fiber (CF composites were improved significantly as compared to the CF composites made from unmodified epoxy. The reasons could be attributed to the strong interfacial interaction between the CF and the epoxy composites for the existence of carbon nanomaterials. The microstructure and dispersion of carbon nanomaterials were characterized by transmission electron microscopy (TEM and optical microscopy (OM. The results showed that the dispersion of the hybrid materials in the polymer was superior to other carbon nanomaterials. The high viscosity and shear stress characterized by a rheometer and the high interfacial friction and damping behavior characterized by dynamic mechanical analysis (DMA indicated that the strong interfacial interaction was greatly improved between fibers and epoxy composites. Remarkably, the tensile tests presented that the CF composites with hybrid materials and epoxy composites have a better reinforcing and toughening effect on CF, which further verified the strong interfacial interaction between epoxy and CF for special structural hybrid materials.

  14. Coated Glass Slides TACAS Are Applicable to Heat-Assisted Immunostaining and In Situ Hybridization at the Electron Microscopy Level

    International Nuclear Information System (INIS)

    Matsui, Takahiro; Onouchi, Takanori; Shiogama, Kazuya; Mizutani, Yasuyoshi; Inada, Ken-ichi; Yu, Fuxun; Hayasaka, Daisuke; Morita, Koichi; Ogawa, Hirohisa; Mahara, Fumihiko; Tsutsumi, Yutaka

    2015-01-01

    We performed pre-embedding electron microscopic study for visualizing the antigen and genome of severe fever with thrombocytopenia syndrome (SFTS) virus in the cytoplasm of macrophages of the human splenic red pulp, both requesting preheating treatment of sections. To pursue this, coated glass slides with unique characteristics are needed. Namely, during staining they must prevent detaching off sections, but after staining the sections must be transferred to epoxy resin. Aminopropyltriexoxysilane-coated glass slides, widely used for immunostaining, were resistant to transfer to epoxy resin. In contrast, coated glass slides designated as Thinlayer Advanced Cytology Assay System (TACAS) were suitable for this purpose. The technique is also applicable to the coated glass slide-requiring cytology practice, in which immunocytochemical evaluation is needed after cell transfer to another glass slide

  15. BLISTERING AND DEGRADATION OF POLYURETHANE COATINGS UNDER DIFFERENT ACCELERATED WEATHERING TESTS. (R828081E01)

    Science.gov (United States)

    An epoxy primer with a high gloss polyurethane topcoat coating system was exposed either only in a QUV chamber or exposed in a QUV chamber and a Prohesion chamber, alternatively, in this study. AFM studies found that micro blisters formed on the coating surface after both expo...

  16. Electrochemical behaviors of wax-coated Li powder/Li 4Ti 5O 12 cells

    Science.gov (United States)

    Park, Han Eol; Seong, Il Won; Yoon, Woo Young

    The wax-coated Li powder specimen was effectively synthesized using the drop emulsion technique (DET). The wax layer on the powder was verified by SEM, Focused Ion Beam (FIB), EDX and XPS. The porosity of a sintered wax-coated Li electrode was measured by linear sweep voltammetry (LSV) and compared with that of a bare, i.e., un-coated Li electrode. The electrochemical behavior of the wax-coated Li powder anode cell was examined by the impedance analysis and cyclic testing methods. The cyclic behavior of the wax-coated Li powder anode with the Li 4Ti 5O 12 (LTO) cathode cell was examined at a constant current density of 0.35 mA cm -2 with the cut-off voltages of 1.2-2.0 V at 25 °C. Over 90% of the initial capacity of the cell remained even after the 300th cycle. The wax-coated Li powder was confirmed to be a stable anode material.

  17. Influence of Nanoclay Dispersion Methods on the Mechanical Behavior of E-Glass/Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Mahesh V. Hosur

    2013-08-01

    Full Text Available Common dispersion methods such as ultrasonic sonication, planetary centrifugal mixing and magnetic dispersion have been used extensively to achieve moderate exfoliation of nanoparticles in polymer matrix. In this study, the effect of adding three roll milling to these three dispersion methods for nanoclay dispersion into epoxy matrix was investigated. A combination of each of these mixing methods with three roll milling showed varying results relative to the unmodified polymer laminate. A significant exfoliation of the nanoparticles in the polymer structure was obtained by dispersing the nanoclay combining three roll milling to magnetic and planetary centrifugal mixing methods. This exfoliation promoted a stronger interfacial bond between the matrix and the fiber, which increased the final properties of the E-glass/epoxy nanocomposite. However, a combination of ultrasound sonication and three roll milling on the other hand, resulted in poor clay exfoliation; the sonication process degraded the polymer network, which adversely affected the nanocomposite final properties relative to the unmodified E-glass/epoxy polymer.

  18. Annealing effects on magnetic properties of silicone-coated iron-based soft magnetic composites

    International Nuclear Information System (INIS)

    Wu Shen; Sun Aizhi; Zhai Fuqiang; Wang Jin; Zhang Qian; Xu Wenhuan; Logan, Philip; Volinsky, Alex A.

    2012-01-01

    This paper focuses on novel iron-based soft magnetic composites synthesis utilizing high thermal stability silicone resin to coat iron powder. The effect of an annealing treatment on the magnetic properties of synthesized magnets was investigated. The coated silicone insulating layer was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Silicone uniformly coated the powder surface, resulting in a reduction of the imaginary part of the permeability, thereby increasing the electrical resistivity and the operating frequency of the synthesized magnets. The annealing treatment increased the initial permeability, the maximum permeability, and the magnetic induction, and decreased the coercivity. Annealing at 580 °C increased the maximum permeability by 72.5%. The result of annealing at 580 °C shows that the ferromagnetic resonance frequency increased from 2 kHz for conventional epoxy resin coated samples to 80 kHz for the silicone resin insulated composites. - Highlights: ► Silicone uniformly coated the powder, increased the operating frequency of SMCs. ► The annealing treatment increased the DC properties of SMCs. ► Annealing at 580 °C increased the maximum permeability by 72.5%. ► Compared with epoxy coated, the SMCs had higher resistivity annealing at 580 °C.

  19. Surface coating affects behavior of metallic nanoparticles in a biological environment

    Directory of Open Access Journals (Sweden)

    Darija Domazet Jurašin

    2016-02-01

    Full Text Available Silver (AgNPs and maghemite, i.e., superparamagnetic iron oxide nanoparticles (SPIONs are promising candidates for new medical applications, which implies the need for strict information regarding their physicochemical characteristics and behavior in a biological environment. The currently developed AgNPs and SPIONs encompass a myriad of sizes and surface coatings, which affect NPs properties and may improve their biocompatibility. This study is aimed to evaluate the effects of surface coating on colloidal stability and behavior of AgNPs and SPIONs in modelled biological environments using dynamic and electrophoretic light scattering techniques, as well as transmission electron microscopy to visualize the behavior of the NP. Three dispersion media were investigated: ultrapure water (UW, biological cell culture medium without addition of protein (BM, and BM supplemented with common serum protein (BMP. The obtained results showed that different coating agents on AgNPs and SPIONs produced different stabilities in the same biological media. The combination of negative charge and high adsorption strength of coating agents proved to be important for achieving good stability of metallic NPs in electrolyte-rich fluids. Most importantly, the presence of proteins provided colloidal stabilization to metallic NPs in biological fluids regardless of their chemical composition, surface structure and surface charge. In addition, an assessment of AgNP and SPION behavior in real biological fluids, rat whole blood (WhBl and blood plasma (BlPl, revealed that the composition of a biological medium is crucial for the colloidal stability and type of metallic NP transformation. Our results highlight the importance of physicochemical characterization and stability evaluation of metallic NPs in a variety of biological systems including as many NP properties as possible.

  20. Aging of Organic Matrices, Epoxy Resins; Causas de envejecimiento de matrices organicas. Resinas epoxidicas

    Energy Technology Data Exchange (ETDEWEB)

    Pazos, M.; Prendes, P.; Varela, M.; Paz, S. [Departamento de I mas D de Gairesa, La Coruna (Spain)

    1997-09-01

    Epoxy resins are very important polymers widely used in advance materials. Approximately 200.000 Tns/year are used in different fields such as coating, floor and paving, adhesives, composites, etc. Due to the importance of these polymers, aging studies are necessary. In this work most important aging-factors are described. We have observed that the water plays a very important role in the degradation-process. (Author)

  1. High temperature oxidation behavior of SiC coating in TRISO coated particles

    International Nuclear Information System (INIS)

    Liu, Rongzheng; Liu, Bing; Zhang, Kaihong; Liu, Malin; Shao, Youlin; Tang, Chunhe

    2014-01-01

    Highlights: • High temperature oxidation tests of SiC coating in TRISO particles were carried out. • The dynamic oxidation process was established. • Oxidation mechanisms were proposed. • The existence of silicon oxycarbides at the SiO 2 /SiC interface was demonstrated. • Carbon was detected at the interface at high temperatures and long oxidation time. - Abstract: High temperature oxidation behavior of SiC coatings in tristructural-isotropic (TRISO) coated particles is crucial to the in-pile safety of fuel particles for a high temperature gas cooled reactor (HTGR). The postulated accident condition of air ingress was taken into account in evaluating the reliability of the SiC layer. Oxidation tests of SiC coatings were carried out in the ranges of temperature between 800 and 1600 °C and time between 1 and 48 h in air atmosphere. Based on the microstructure evolution of the oxide layer, the mechanisms and kinetics of the oxidation process were proposed. The existence of silicon oxycarbides (SiO x C y ) at the SiO 2 /SiC interface was demonstrated by X-ray photospectroscopy (XPS) analysis. Carbon was detected by Raman spectroscopy at the interface under conditions of very high temperatures and long oxidation time. From oxidation kinetics calculation, activation energies were 145 kJ/mol and 352 kJ/mol for the temperature ranges of 1200–1500 °C and 1550–1600 °C, respectively

  2. Preliminary study of mechanical behavior for Cr coated Zr-4 Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do-Hyoung; Kim, Hak-Sung [Hanyang Univ., Seoul (Korea, Republic of); Kim, Hyo-Chan; Yang, Yong-Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    To decrease the oxidation rate of Zr-based alloy components, many concepts of accident tolerant fuel (ATF) such as Mo-Zr cladding, SiC/SiCf cladding and iron-based alloy cladding are under development. One of the promised concept is the coated cladding which can remarkably increase the corrosion and wear resistance. Recently, KAERI is developing the Cr coated Zircaloy cladding as accident tolerance cladding. To coat the Cr powder on the Zircaloy, 3D laser coating technology has been employed because it is possible to make a coated layer on the tubular cladding surface by controlling the 3-diminational axis. Therefore, for this work, the mechanical integrity of Cr coated Zircaloy should be evaluated to predict the safety of fuel cladding during the operating or accident of nuclear reactor. In this work, the mechanical behavior of the Cr coated Zircaloy cladding has been studied by using finite element analysis (FEA). The ring compression test (RCT) of fuel cladding was simulated to evaluate the validity of mechanical properties of Zr-4 and Cr, which were referred from the literatures and experimental reports. In this work, the mechanical behavior of the Cr coated Zircaloy cladding has been studied by using finite element analysis (FEA). The ring compression test (RCT) of fuel cladding was simulated to evaluate the validity of mechanical properties of Zr-4 and Cr. The pellet-clad mechanical interaction (PCMI) properties of Cr coated Zr-4 cladding were investigated by thermo-mechanical finite element analysis (FEA) simulation. The mechanical properties of Zr-4 and Cr was validated by simulation of ring compression test (RCT) of fuel cladding.

  3. WEATHERING DEGRADATION OF A POLYURETHANE COATING. (R828081E01)

    Science.gov (United States)

    The degradation of polyurethane topcoat over a chromate pigmented epoxy primer was examined by atomic force microscopy (AFM), scanning electronic microscopy (SEM), X-ray photo-electron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR) after the coated pane...

  4. Epoxy-based carbon nanotubes reinforced composites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2011-04-01

    Full Text Available of the three major epoxy resin producers worldwide [May, 1987]. Epoxy resin is most commonly used as a matrix for advanced composites due to their superior thermal, mechanical and electrical properties; dimensional stability and chemical resistance. Epoxy... and modifiers to create products with an almost unlimited range and variety of performance properties [The epoxy book, 2000]. Epoxy resins are widely used as high-grade synthetic resins, for example, in the electronics, aeronautics and astronautic industries...

  5. Interaction of water with epoxy.

    Energy Technology Data Exchange (ETDEWEB)

    Powers, Dana Auburn

    2009-07-01

    The chemistries of reactants, plasticizers, solvents and additives in an epoxy paint are discussed. Polyamide additives may play an important role in the absorption of molecular iodine by epoxy paints. It is recommended that the unsaturation of the polyamide additive in the epoxy cure be determined. Experimental studies of water absorption by epoxy resins are discussed. These studies show that absorption can disrupt hydrogen bonds among segments of the polymers and cause swelling of the polymer. The water absorption increases the diffusion coefficient of water within the polymer. Permanent damage to the polymer can result if water causes hydrolysis of ether linkages. Water desorption studies are recommended to ascertain how water absorption affects epoxy paint.

  6. Effection of UV-LED Illuminant on the Curation of Photolatent-amidine Mixed with Bisphenol A Epoxy Acrylate under Printing Conditions

    Directory of Open Access Journals (Sweden)

    Duan Huawei

    2016-01-01

    Full Text Available In order to make photocuring ink or coating cured by UV-LED illuminant, we synthesized (4-((hexahydropyrrolo[1,2-a]pyrimidin-1 (2H-ylmethylphenyl(phenylmethanone(PL -DBN and (4-((octahydropyrimido[1,2-a]azepin-1(2H-ylmethylphenyl(phenylmet hanone(PL -DBU as photoinitiators. Different mass fraction of the photoinitiators was mixed with bisphenol A epoxy acrylate, cured by different wavelengths and power of UV-LED illuminant,and investigated the curing effects of photoinitiators on bisphenol A epoxy acrylate. The results show that the conversion of C=C double bonds of bisphenol A epoxy acrylate will increase as the mass fraction of the photoinitiators or the power of UV-LED illuminant increase. In the same conditions, the curing effect of using 365nm UV-LED illuminant on bisphenol A epoxy acrylate is better than using 395nm UV-LED illuminant. PL-DBU has a better curing effect on the bisphenol A epoxy acrylate rather than PL-DBN. When using the 8W/cm2 of 365nm UV-LED illuminant to cure a mixture of 3% PL-DBU and 97% bisphenol A epoxy acrylate, it will be dry completely in 2 seconds, moreover, the conversion reach 79%.

  7. Deflection and Flexural Strength Effects on the Roughness of Aesthetic-Coated Orthodontic Wires

    OpenAIRE

    Albuquerque, Cibele Gonçalves de; Correr, Américo Bortolazzo; Venezian, Giovana Cherubini; Santamaria Jr, Milton; Tubel, Carlos Alberto; Vedovello, Silvia Amélia Scudeler

    2017-01-01

    Abstract The aim was to evaluate the flexural strength and the effects of deflection on the surface roughness of esthetic orthodontic wires. The sample consisted of 70 archwire 0.014-inch: polytetrafluorethylene (PTFE)-coated Nickel-Titanium (Niti) archwires (Titanol Cosmetic-TC, Flexy Super Elastic Esthetic-FSE, esthetic Nickel Titanium Wire-ANT); epoxy resin-coated Niti archwires (Spectra-S, Niticosmetic-TEC); gold and rhodium coated Niti (Sentalloy-STC) and a control group (superelastic Ni...

  8. Allergic contact dermatitis from resin hardeners during the manufacture of thermosetting coating paints.

    Science.gov (United States)

    Foulds, I S; Koh, D

    1992-02-01

    5 production operators from 2 factories manufacturing thermosetting coating paint developed work-related skin disorders within 12 months of the introduction of a new powdered paint product. All 5 workers were found to have allergic contact dermatitis from 2 epoxy resin hardeners, both of which were commercial preparations of triglycidyl isocyanurate (TGIC). 2 of the workers had concomitant sensitization to epoxy resin in the standard series and several of the epoxy resin preparations at the workplace. TGIC has been reported as a contact sensitizer both in persons producing the chemical and among end-users of TGIC-containing products. These 5 reported cases document allergic contact dermatitis from commercial TGIC among exposed workers during an intermediate process of powdered paint manufacture. The possibility of substituting this epoxy resin hardener with less sensitizing alternatives should be explored.

  9. Emerging Nanotechnology-based Corrosion Control Coatings

    Science.gov (United States)

    2009-02-01

    Carbon black Calcium carbonate Carbon nanotubes Cerium oxide Dendrimers, hyperbranched and supramolecules Indium... Microcapsule with Bisphenol A epoxy Microcapsule with Ketimine O O O O O O O H O n Selected SEM images of various microcapsules SEM and optical...microscopy images of cross-section of self-healing coating Microcapsule rupture and healing agent release is triggered by: T> Tm

  10. Self-constructed tree-shape high thermal conductivity nanosilver networks in epoxy.

    Science.gov (United States)

    Pashayi, Kamyar; Fard, Hafez Raeisi; Lai, Fengyuan; Iruvanti, Sushumna; Plawsky, Joel; Borca-Tasciuc, Theodorian

    2014-04-21

    We report the formation of high aspect ratio nanoscale tree-shape silver networks in epoxy, at low temperatures (thermal conductivity (κ) of the nanocomposite compared to the polymer matrix. The networks form through a three-step process comprising of self-assembly by diffusion limited aggregation of polyvinylpyrrolidone (PVP) coated nanoparticles, removal of PVP coating from the surface, and sintering of silver nanoparticles in high aspect ratio networked structures. Controlling self-assembly and sintering by carefully designed multistep temperature and time processing leads to κ of our silver nanocomposites that are up to 300% of the present state of the art polymer nanocomposites at similar volume fractions. Our investigation of the κ enhancements enabled by tree-shaped network nanocomposites provides a basis for the development of new polymer nanocomposites for thermal transport and storage applications.

  11. Improved anti-stiction coating of SU-8 molds

    DEFF Research Database (Denmark)

    Lange, Jacob Moresco; Clausen, Casper Hyttel; Svendsen, Winnie Edith

    2010-01-01

    of the epoxy groups by oxygen plasma or sulfuric acid improves the deposition of FDTS. The deposition of FDTS on acid-activated and untreated SU-8 gave an identical well performing anti-stiction coating, as opposed to oxygen plasma activated surface which resulted in a poor FDTS coverage. In this paper...

  12. Contact allergy to epoxy resin

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil

    2012-01-01

    Background. Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown...... in an educational programme. Conclusion. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required....

  13. Corrosion behavior of niobium coated 304 stainless steel in acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Pan, T.J., E-mail: tjpan@cczu.edu.cn [School of Material Science and Engineering, Jiangsu Collaborative Innovation Center for Photovolatic Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Material Surface Technology, Changzhou 213164 (China); Chen, Y.; Zhang, B. [School of Material Science and Engineering, Jiangsu Collaborative Innovation Center for Photovolatic Science and Engineering, Changzhou University, Changzhou 213164 (China); Hu, J. [School of Material Science and Engineering, Jiangsu Collaborative Innovation Center for Photovolatic Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Material Surface Technology, Changzhou 213164 (China); Li, C. [Light Industry College of Liaoning University, Shenyang 110036 (China)

    2016-04-30

    Highlights: • The Nb coating produced by HEMAA offers good protection for 304SS in acid solution. • The coating increases corrosion potential and induces decrease of corrosion rate. • The protection of coating is ascribed to the stability of Nb in acid solution. - Abstract: The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

  14. Corrosion behavior of niobium coated 304 stainless steel in acid solution

    International Nuclear Information System (INIS)

    Pan, T.J.; Chen, Y.; Zhang, B.; Hu, J.; Li, C.

    2016-01-01

    Highlights: • The Nb coating produced by HEMAA offers good protection for 304SS in acid solution. • The coating increases corrosion potential and induces decrease of corrosion rate. • The protection of coating is ascribed to the stability of Nb in acid solution. - Abstract: The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

  15. Bacterial colonization on coated and uncoated orthodontic wires: A prospective clinical trial

    OpenAIRE

    Seyed Hamid Raji; Hasan Shojaei; Parinaz Saeidi Ghorani; Elahe Rafiei

    2014-01-01

    Background: The advantages of coated orthodontic wires such as esthetic and their effects on reduced friction, corrosion and allergic reaction and the significant consequences of plaque accumulation on oral health encouraged us to assess bacterial colonization on these wires. Materials and Methods: A total of 18 (9 upper and 9 lower) epoxy resin coated 16 × 22 nickel-titanium wires (Spectra, GAC, USA) and 18 (9 upper and 9 lower) non-coated 16 × 22 nickel-titanium wires (Sentalloy, GAC, U...

  16. Characterization of Bovine Serum Albumin Blocking Efficiency on Epoxy-Functionalized Substrates for Microarray Applications.

    Science.gov (United States)

    Sun, Yung-Shin; Zhu, Xiangdong

    2016-10-01

    Microarrays provide a platform for high-throughput characterization of biomolecular interactions. To increase the sensitivity and specificity of microarrays, surface blocking is required to minimize the nonspecific interactions between analytes and unprinted yet functionalized surfaces. To block amine- or epoxy-functionalized substrates, bovine serum albumin (BSA) is one of the most commonly used blocking reagents because it is cheap and easy to use. Based on standard protocols from microarray manufactories, a BSA concentration of 1% (10 mg/mL or 200 μM) and reaction time of at least 30 min are required to efficiently block epoxy-coated slides. In this paper, we used both fluorescent and label-free methods to characterize the BSA blocking efficiency on epoxy-functionalized substrates. The blocking efficiency of BSA was characterized using a fluorescent scanner and a label-free oblique-incidence reflectivity difference (OI-RD) microscope. We found that (1) a BSA concentration of 0.05% (0.5 mg/mL or 10 μM) could give a blocking efficiency of 98%, and (2) the BSA blocking step took only about 5 min to be complete. Also, from real-time and in situ measurements, we were able to calculate the conformational properties (thickness, mass density, and number density) of BSA molecules deposited on the epoxy surface. © 2015 Society for Laboratory Automation and Screening.

  17. Studies on the structural changes during curing of epoxy and its blend with CTBN

    Science.gov (United States)

    Srivastava, Kavita; Rathore, Ashwani Kumar; Srivastava, Deepak

    2018-01-01

    Cashew nut shell liquid (CNSL), an agricultural renewable resource material, produces natural phenolic distillates such as cardanol. Cardanol condenses with formaldehyde at the ortho- and para-position of the phenolic ring under acidic or alkaline condition to yield a series of polymers of novolac- or resol-type phenolic resins. These phenolic resins may further be modified by epoxidation with epichlorohydrin to duplicate the performance of such phenolic-type novolacs (CFN). The structural changes during curing of blend samples of epoxy and carboxyl terminated poly (butadiene-co-acrylonitrile) (CTBN) were studies by Fourier-transform infrared (FTIR) spectrophotometer. The epoxy samples were synthesized by biomass material, cardanol. Blend sample was prepared by physical mixing of CTBN ranging between 0 and 20 weight percent CTBN liquid rubber into cardanol-based epoxidized novolac (CEN) resin. The FTIR spectrum of uncured blend sample clearly indicated that there appeared a band in the region of 3200-3500 cm- 1 which might be due to the presence of phenolic hydroxyl group and sbnd OH group of the opened epoxide. Pure epoxy resin showed peaks near 856 cm- 1 which might be due to oxirane functionality of the epoxidized novolac resin. Both epoxy and its blend sample was cured with polyamine. The cure temperature of CEN resin was found to be decreased by the incorporation of CTBN. The decomposition behavior was also studied by thermogravimetric analyzer (TGA). Two-step decomposition behavior was observed in both epoxy and its blend samples.

  18. Tribological behavior of dual-layer electroless-plated Ag–carbon nanotube coatings

    International Nuclear Information System (INIS)

    Lee, Hyun-Dai; Penkov, Oleksiy V.; Kim, Dae-Eun

    2013-01-01

    The tribological behavior of electroless Ag-plated carbon nanotube (CNT) dual-layer coatings was assessed and compared to that of the pure CNT coating. The motivation was to protect the surface of CNT coatings from wear by depositing a thin, soft Ag coating. The methods used for coating CNTs and Ag were spin coating and electroless plating, respectively. These coating methods were selected based on their simplicity and cost effectiveness. Wear tests were conducted by sliding the coatings against a stainless steel ball under a 10–30 mN applied load. Results showed that the wear rate of the dual-layer coating was strongly dependent on the thickness of the Ag layer as well as the applied load. At a 10 mN load and an Ag thickness of 65 nm, the wear rate of the dual-layer coating was about 10 times less than that of the pure CNT coating. However, when the thickness of the Ag was decreased to 11.5 nm, the wear rate was significantly higher. Also, the steady-state friction coefficients of the CNT and the dual-layer Ag–CNT coatings were in the range of 0.65–0.73 for all loads. A model of the wear reduction mechanism of the dual-layer Ag–CNT coating was proposed. - Highlights: ► Dual-layer Ag–carbon nanotube (CNT) coatings were deposited on silicon wafer. ► Friction coefficient of the Ag–CNT coatings was about 0.65. ► Wear of Ag–CNT coatings depended on the thickness of Ag layer and the applied load. ► Wear rate of the Ag–CNT coating was 10-fold less than that of the pure CNT coating

  19. Effect of Filler Content on the Performance of Epoxy/PTW Composites

    Directory of Open Access Journals (Sweden)

    Mudradi Sudheer

    2014-01-01

    Full Text Available This paper presents the mechanical and tribological characteristics of potassium titanate whisker (PTW reinforced epoxy composites. The effect of various test variables and material parameters on the friction and wear behavior of epoxy/PTW composites has been studied systematically. Tribological tests were conducted on a pin-on-disc apparatus under dry sliding conditions. Addition of PTW was found to improve the wear resistance of the composites and 15 wt% PTW filled epoxy exhibited lowest specific wear rate and highest friction coefficient compared to other test samples. PTW additions showed beneficiary effect on density, hardness, and stiffness properties of composites; however, strength properties and ductility were found to decrease with the increasing content of PTW. Scanning electron microscope (SEM images of tensile fractured surfaces and worn-out surfaces of selected samples revealed different fracture mechanisms.

  20. ANALISIS ARAH DAN PERLAKUAN SERAT TAPIS SERTA RASIO EPOXY HARDENER TERHADAP SIFAT FISIS DAN MEKANIS KOMPOSIT TAPIS/EPOXY

    Directory of Open Access Journals (Sweden)

    Putu Lokantara

    2012-11-01

    Full Text Available Tapis kelapa (Coconut filter as natural fiber, in this time its resources very copius but no longer be exploited and thrown off hand as waste though in fact its used for other material dissimilar inovatif and high economic valuable that is as one of natural fiber alternative to be composite. The objective of this research is to investigate the behavior changing of physical and mechanical properties of composite tapis kelapa as reinforcement and epoxy 7120 with hardener Versamid 140 as matrix. The fiber is treated with the chemical NaOH and KMnO4 with percentage 0.5%, 1%, and 2% in weight, respectively. The ratio of epoxy and hardener is 7:3 and 6:4, and fiber orientation 0o, 45o, dan 90o. For testing of the speciment in tensile test with ASTM standard D3039 and three point bending test with ASTM standard D790. The result of this research obtained that fiber treatment with KMnO4 give the better effect to machine properties compared to NaOH. Variation of percentage 0.5%, 1%, and 2% NaOH and KMnO4 give the effect in fiber surface which higher percentage make the cleaner of surface, decrease of wax contain, and roughness of fiber surface so that stronger of linkage of fiber and matrix and increase of tensile strength, bending strength, and bending modulus of the composite. The highest tensile strength, modulus of elasticity and bending strength are 70.23 MPa, 446.24 GPa and 97.81 MPa respectively reached at composite with ratio epoxy/hardener 7:3; by 2% KMnO4 and fiber orientation 45o. While the highest modulus of elasticity is 385.48 GPa reached at composite with the ratio epoxy/hardener 6:4; 2% KMnO4 and fiber orientation 90o. Keywords: Tensile Strength, bending strength, ratio of epoxy/hardener, NaOH, KMnO4

  1. The use of Electronic Speckle Pattern Interferometry (ESPI) in the crack propagation analysis of epoxy resins

    Science.gov (United States)

    Herbert, D. P.; Al-Hassani, A. H. M.; Richardson, M. O. W.

    The ESPI (electronic speckle pattern interferometry) technique at high magnification levels is demonstrated to be of considerable value in interpreting the fracture behaviour of epoxy resins. The fracture toughness of powder coating system at different thicknesses has been measured using a TDCB (tapered double cantilever beam) technique and the deformation zone at the tip of the moving crack monitored. Initial indications are that a mechanistic changeover occurs at a critical bond (coating) thickness and that this is synonymous with the occurence of a fracture toughness maximum, which in turn is associated with a deformation zone of specific diameter.

  2. Self-assembly of a superparamagnetic raspberry-like silica/iron oxide nanocomposite using epoxy-amine coupling chemistry.

    Science.gov (United States)

    Cano, Manuel; de la Cueva-Méndez, Guillermo

    2015-02-28

    The fabrication of colloidal nanocomposites would benefit from controlled hetero-assembly of ready-made particles through covalent bonding. Here we used epoxy-amine coupling chemistry to promote the self-assembly of superparamagnetic raspberry-like nanocomposites. This adaptable method induced the covalent attachment of iron oxide nanoparticles sparsely coated with amine groups onto epoxylated silica cores in the absence of other reactants.

  3. Nonlinear Stress-Strain Behavior of Plasma Sprayed Ceramic Coatings

    Czech Academy of Sciences Publication Activity Database

    Nohava, Jiří; Kroupa, František

    2005-01-01

    Roč. 50, č. 3 (2005), s. 251-262 ISSN 0001-7043 R&D Projects: GA AV ČR KSK1010104 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * ceramic coatings * Young’s modulus * nonlinear behavior * microcracks Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  4. Structure and wear behavior of AlCrSiN-based coatings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yun [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Chengdu Tool Research Institute Co., Ltd., Chengdu 610500 (China); Du, Hao [School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065 (China); Chen, Ming, E-mail: mchen@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Yang, Jun [Chengdu Tool Research Institute Co., Ltd., Chengdu 610500 (China); Xiong, Ji [School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065 (China); Zhao, Haibo [The Analysis and Testing Centre, Sichuan University, Chengdu 610065 (China)

    2016-05-01

    Graphical abstract: - Highlights: • AlCrSiN based coating showed amorphous structure. • AlCrSiN/Me{sub x}N coatings obtained better wear resistance. • Molybdenum and niobium increased the coating hardness and wear resistance. - Abstract: AlCrN, AlCrSiCN, AlCrSiN/MoN, and AlCrSiN/NbN coatings have been deposited on high-polished WC–Co cemented carbide substrate and tools by mid-frequency magnetron sputtering in Ar/N{sub 2} mixtures. Al{sub 0.6}Cr{sub 0.4}, Al{sub 0.6}Cr{sub 0.3}Si{sub 0.1}, and C/Mo/Nb targets were used during the deposition. The microstructure and mechanical properties of as-deposited coatings were investigated. Investigations of the wear behaviors of coated tools were also performed. The results showed that cubic structure was formed in the coatings. Broader CrAlN (1 1 1) and (2 0 0) peaks without SiN{sub x} peak were formed in the AlCrSiN/Me{sub x}N coatings, which showed a nanocomposited structure. Meanwhile, according to SEM micrographs, AlCrN exhibited a columnar structure, while, AlCrSiCN, AlCrSiN/MoN, and AlCrSiN/NbN coatings showed nanocrystalline morphology. The nano-multilayered coatings performed higher hardness, H/E, and H{sup 3}/E{sup 2} ratios compared with AlCrN coating. Through the Rockwell adhesion test, all the coatings exhibited adhesion strength quality HF1. After turning Inconel 718 under dry condition, the nano-multilyered coatings showed better wear resistance than AlCrN coating. Due to the molybdenum and niobium in the coating, AlCrSiN/MoN and AlCrSiN/NbN coatings showed the best wear resistance.

  5. Foil Bearing Coating Behavior in CO2

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Matthew [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Pasch, James Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fleming, Darryn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-08-01

    The Sandia S-CO2 Recompression Closed Brayton Cycle (RCBC) utilizes a series of gas foil bearings in its turbine-alternator-compressors. At high shaft rotational speed these bearings allow the shaft to ride on a cushion of air. Conversely, during startup and shutdown, the shaft rides along the foil bearing surface. Low-friction coatings are used on bearing surfaces in order to facilitate rotation during these periods. An experimental program was initiated to elucidate the behavior of coated bearing foils in the harsh environments of this system. A test configuration was developed enabling long duration exposure tests, followed by a range of analyses relevant to their performance in a bearing. This report provides a detailed overview of this work. The results contained herein provide valuable information in selecting appropriate coatings for more advanced future bearing-rig tests at the newly established test facility in Sandia-NM.

  6. Improved HgCdTe detectors with novel antireflection coating

    Science.gov (United States)

    Babu, Sachi R.; Hu, Kelley; Manthripragada, Sridhar; Martineau, Robert J.; Kotecki, C. A.; Peters, F. A.; Burgess, A. S.; Krebs, Danny J.; Mott, David B.; Ewin, Audrey J.; Miles, A.; Nguyen, Trang L.; Shu, Peter K.

    1996-10-01

    The composite infrared spctrometer (CIRS) is an important instrument for the upcoming Cassini mission for sensing infrared (IR) radiation from the Saturanian planetary system. We have delivered a linear, ten element, mercury cadmium telluride (HgCdTe) photoconductive detector array for use on focal plane 3 (FP3), which is responsible for detecting radiation from the 9.1 micrometer to 16.6 micrometer wavelength range. Reliable HgCdTe detectors require robust passivation, a low-stress zinc sulfide (ZnS) anti-reflection (AR) coating with good adhesion, and a proper optical cavity design to smooth out the resonance in the detector spectral response. During the development of CIRS flight array, we have demonstrated the potential of using an in-situ interfacial layer, such as SiN(subscript x), between ZnS and the anodic oxide. Such an interfacial layer drastically improves the adhesion between the ZnS and oxide, without degrading the minority carrier lifetime. We have also demonstrated the feasibility of applying a SiN(subscript x) 'rain coat' layer over the ZnS to prevent moisture and other chemicals from attacking the AR coating, thus improving the long term reliability. This also enables device operation in a hazardous environment. The alumina/epoxy/HgCdTe/oxide/ZnS structure is a complicated multi-cavity optical system. We have developed an extensive device simulation, which enables us to make the optimal choice of individual cavity thickness for minimizing the resonance and maximizing the quantum efficiency. We have also used 0.05 micrometer alumina powder loaded epoxy to minimize the reflections at the epoxy/HgCdTe interface, thus minimizing the resonance.

  7. Corrosion behavior of biodegradable material AZ31 coated with beeswax-colophony resin

    Science.gov (United States)

    Gumelar, Muhammad Dikdik; Putri, Nur Ajrina; Anggaravidya, Mahendra; Anawati, Anawati

    2018-05-01

    Magnesium (Mg) and its alloys are potential candidates for biodegradable implant materials owing to their ability to degrade spontaneously in a physiological environment. However, the degradation rate is still considered too fast in human body solution. A coating is typically applied to slowdown corrosion rate of Mg alloys. In this work, an organic coating of mixture beeswax-colophony with ratios of 40-60, 50-50, and 60-40 in wt% was synthesized and applied on commercial magnesium alloyAZ31. The coated specimens were then characterized with SEM and XRF. The corrosion behavior of the coated specimens was evaluated by immersion test in 0.9 wt% NaCl solution at 37°C for 14 days. The results indicated that the coating material improved the corrosion resistance of the AZ31 alloy.

  8. Electrochemical behavior of monolayer and bilayer graphene.

    Science.gov (United States)

    Valota, Anna T; Kinloch, Ian A; Novoselov, Kostya S; Casiraghi, Cinzia; Eckmann, Axel; Hill, Ernie W; Dryfe, Robert A W

    2011-11-22

    Results of a study on the electrochemical properties of exfoliated single and multilayer graphene flakes are presented. Graphene flakes were deposited on silicon/silicon oxide wafers to enable fast and accurate characterization by optical microscopy and Raman spectroscopy. Conductive silver paint and silver wires were used to fabricate contacts; epoxy resin was employed as a masking coating in order to expose a stable, well-defined area of graphene. Both multilayer and monolayer graphene microelectrodes showed quasi-reversible behavior during voltammetric measurements in potassium ferricyanide. However, the standard heterogeneous charge transfer rate constant, k°, was estimated to be higher for monolayer graphene flakes. © 2011 American Chemical Society

  9. Scheming of microwave shielding effectiveness for X band considering functionalized MWNTs/epoxy composites

    Science.gov (United States)

    Bal, S.; Saha, S.

    2016-02-01

    Present typescript encompasses anextraordinary electrical and mechanical behaviors of carboxylic (-COOH) functionalized multiwall carbon nanotube (MWNTs)/epoxy composites at low wt.% (0,5, 0,75, 1wt.%). Functionalization on the surface of the nanotube assists MWNTs in dispersing it into epoxy polymer in a respectable manner, Fabricated composites are exposed to different characterization techniques in order to examine the overall physical properties, Microwave shielding effectiveness (SE) for X band (8-12 GHz) and the flexural properties have been premeditated to predict the electrical and mechanical performances. It was found that the total SE of the nanocomposites was increased with the positive gradient of MWNT contents, The best result was recorded for 1 wt.% MWNT loading (SE of about 51,72 dB).In addition, incorporation of nanofillers enhanced the flexural modulus, flexural strength and micro-hardness of the resulting composites while comparing with neat epoxy, Nanocomposites with 0,75 wt,% MWNT loading demonstrated an incrementof 101% in modulus than that of neat epoxy, Theincrement in mechanical properties was due to achievement of good dispersion quality, effective bonding between MWNTs and epoxy polymer analyzed by micrographs of fracture surfaces

  10. Scheming of microwave shielding effectiveness for X band considering functionalized MWNTs/epoxy composites

    International Nuclear Information System (INIS)

    Bal, S; Saha, S

    2016-01-01

    Present typescript encompasses anextraordinary electrical and mechanical behaviors of carboxylic (-COOH) functionalized multiwall carbon nanotube (MWNTs)/epoxy composites at low wt.% (0,5, 0,75, 1wt.%). Functionalization on the surface of the nanotube assists MWNTs in dispersing it into epoxy polymer in a respectable manner, Fabricated composites are exposed to different characterization techniques in order to examine the overall physical properties, Microwave shielding effectiveness (SE) for X band (8-12 GHz) and the flexural properties have been premeditated to predict the electrical and mechanical performances. It was found that the total SE of the nanocomposites was increased with the positive gradient of MWNT contents, The best result was recorded for 1 wt.% MWNT loading (SE of about 51,72 dB).In addition, incorporation of nanofillers enhanced the flexural modulus, flexural strength and micro-hardness of the resulting composites while comparing with neat epoxy, Nanocomposites with 0,75 wt,% MWNT loading demonstrated an incrementof 101% in modulus than that of neat epoxy, Theincrement in mechanical properties was due to achievement of good dispersion quality, effective bonding between MWNTs and epoxy polymer analyzed by micrographs of fracture surfaces (paper)

  11. Wettability of nano-epoxies to UHMWPE fibers.

    Science.gov (United States)

    Neema, S; Salehi-Khojin, A; Zhamu, A; Zhong, W H; Jana, S; Gan, Y X

    2006-07-01

    Ultra high molecular weight polyethylene (UHMWPE) fibers have a unique combination of outstanding mechanical, physical, and chemical properties. However, as reinforcements for manufacturing high performance composite materials, UHMWPE fibers have poor wettability with most polymers. As a result, the interfacial bonding strength between the fibers and polymer matrices is very low. Recently, developing so-called nano-matrices containing reactive graphitic nanofibers (r-GNFs) has been proposed to promote the wetting of such matrices to certain types of fiber reinforcements. In this work, the wettability of UHMWPE fibers with different epoxy matrices including a nano-epoxy, and a pure epoxy was investigated. Systematic experimental work was conducted to determine the viscosity of the epoxies, the contact angle between the epoxies and the fibers. Also obtained are the surface energy of the fibers and the epoxies. The experimental results show that the wettability of the UHMWPE fibers with the nano-epoxy is much better than that of the UHMWPE fibers with the pure epoxy.

  12. Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

    Directory of Open Access Journals (Sweden)

    Ungyu Paik

    2013-08-01

    Full Text Available The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF and low-pressure plasma spray (LPPS methods showed a partial cracking (and/or delamination and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50% after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF.

  13. Surface chemical functionalisation of epoxy photoresist-based microcantilevers with organic-coated TiO2 nanocrystals

    DEFF Research Database (Denmark)

    Ingrosso, C.; Sardella, E.; Keller, S. S.

    2012-01-01

    In this Letter, a solution-based approach has been used for chemically immobilising oleic acid (OLEA)-capped TiO2 nanocrystals (NCs) on the surface of microcantilevers formed of SU-8, a negative tone epoxy photoresist. The immobilisation has been carried out at room temperature, under visible lig...

  14. Electrically conductive, black thermal control coatings for spacecraft applications. III - Plasma-deposited ceramic matrix

    Science.gov (United States)

    Hribar, V. F.; Bauer, J. L.; O'Donnell, T. P.

    1987-01-01

    Five black, electrically-conductive thermal control coatings have been formulated and tested for application on the Galileo spacecraft. The coatings consist of both organic and inorganic systems applied on titanium, aluminum, and glass/epoxy composite surfaces. The coatings were tested under simulated space environment conditions. Coated specimens were subjected to thermal radiation, convective and combustive heating, and cryogenic conditions over a temperature range between -196 C and 538 C. Mechanical, physical, thermal, electrical, and thermooptical properties are presented for one of these coatings. This paper describes the preparation, characteristics, and spraying of iron titanate on titanium and aluminum, and presents performance results.

  15. Preparation, Characterization, and Modeling of Carbon Nano fiber/Epoxy Nano composites

    International Nuclear Information System (INIS)

    Sun, L.H.; Yang, Z.G.; Ounaies, Z.; Whalen, C.A.; Gao, X.L.

    2011-01-01

    There is a lack of systematic investigations on both mechanical and electrical properties of carbon nano fiber (CNF)-reinforced epoxy matrix nano composites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nano composites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nano composites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nano composite with a 1.0 wt % CNFs. The alternate-current (AC) electrical properties of the CNF/epoxy nano composites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt % (0.058 vol %) CNFs and by ten orders of magnitude for nano composites with CNF volume fractions higher than 1.0 wt % (0.578 vol %). The percolation threshold (i.e., the critical CNF volume fraction) is found to be at 0.057 vol %.

  16. Effect of nanoclay on thermal, mechanical and liquid absorption properties of epoxy-clay nanocomposite

    International Nuclear Information System (INIS)

    Nguyen Cong Quyen; Nguyen Pham Duy Linh; Bui Chuong; Doan Thi Yen Oanh

    2015-01-01

    Composite materials based on epoxy DER 331 hot cured by MHHPA with several contents of nanoclay I28E were prepared and characterized by TEM and SEM. Results showed that the nanostructures were created in two levels: intercalated structure and nanoparticles (cluster). The interaction between nanoclay and epoxy matrix was evaluated by properties such as: liquid absorption, TGA and DMA. It was shown that nanostructures of cluster, as well as the hydrophobic behavior of material with the presence of nanoclay have dominant effect to liquid absorption. Otherwise, the thermal stability was affected mainly by intercalation structure. Results of DMA showed that the interaction of epoxy-clay was strongly destroyed at the temperature higher than material Tg. (author)

  17. Delamination R-curve as a material property of unidirectional glass/epoxy composites

    International Nuclear Information System (INIS)

    Shokrieh, M.M.; Heidari-Rarani, M.; Ayatollahi, M.R.

    2012-01-01

    Highlights: → The R-curve behavior of a unidirectional laminate as a material property is investigated. → Effect of initial crack length and thickness on R-curve is experimentally shown. → A mathematical relation is proposed to model the R-curve behavior of any unidirectional laminated composite. -- Abstract: It is still questionable to think of delamination resistance of a double cantilever beam (DCB) as a material property independent of the specimen size and geometry. In this research, the effects of initial crack length and DCB specimen thickness on the mode I delamination resistance curve (R-curve) behavior of different unidirectional glass/epoxy DCB specimens are experimentally investigated. It is observed that the magnitudes of initiation and propagation delamination toughness (G Ic-init and G Ic-prop ) as well as the fiber bridging length are constant in a specific range of the initial crack length to the DCB specimen thickness ratios of 8.5 0 /h < 19. Finally, a mathematical relationship is proposed for prediction of mode I delamination behavior (from the initiation to propagation) of E-glass/epoxy DCB specimens.

  18. Degradation and failure characteristics of NPP containment protective coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.

    2000-03-30

    A research program to investigate the performance and potential for failure of Service Level 1 coating systems used in nuclear power plant containment is in progress. The research activities are aligned to address phenomena important to cause failure as identified by the industry coatings expert panel. The period of interest for performance covers the time from application of the coating through 40 years of service, followed by a medium-to-large break loss-of-coolant accident scenario, which is a design basis accident (DBA) scenario. The interactive program elements are discussed in this report and the application of these elements to the System 5 coating system (polyamide epoxy primer, carbon steel substrate) is used to evaluate performance.

  19. Degradation and failure characteristics of NPP containment protective coating systems

    International Nuclear Information System (INIS)

    Sindelar, R.L.

    2000-01-01

    A research program to investigate the performance and potential for failure of Service Level 1 coating systems used in nuclear power plant containment is in progress. The research activities are aligned to address phenomena important to cause failure as identified by the industry coatings expert panel. The period of interest for performance covers the time from application of the coating through 40 years of service, followed by a medium-to-large break loss-of-coolant accident scenario, which is a design basis accident (DBA) scenario. The interactive program elements are discussed in this report and the application of these elements to the System 5 coating system (polyamide epoxy primer, carbon steel substrate) is used to evaluate performance

  20. Epoxy-based carbon nanotubes reinforced composites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2011-04-01

    Full Text Available of the three major epoxy resin producers worldwide [May, 1987]. Epoxy resin is most commonly used as a matrix for advanced composites due to their superior thermal, mechanical and electrical properties; dimensional stability and chemical resistance. Epoxy... are electrical insulators, and the widespread use of the epoxy resins for many high-performance applications is constrained because of their inherent brittleness, delamination and fracture toughness limitations. There were quite a few approaches to enhance...

  1. Silica coating of nanoparticles by the sonogel process.

    Science.gov (United States)

    Chen, Quan; Boothroyd, Chris; Tan, Gim Hong; Sutanto, Nelvi; Soutar, Andrew McIntosh; Zeng, Xian Ting

    2008-02-05

    A modified aqueous sol-gel route was developed using ultrasonic power for the silica coating of indium tin oxide (ITO) nanoparticles. In this approach, organosilane with an amino functional group was first used to cover the surface of as-received nanoparticles. Subsequent silica coating was initiated and sustained under power ultrasound irradiation in an aqueous mixture of surface-treated particles and epoxy silane. This process resulted in a thin but homogeneous coverage of silica on the particle surface. Particles coated with a layer of silica show better dispersability in aqueous and organic media compared with the untreated powder. Samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and the zeta potential.

  2. Fabrication and properties of iron-based soft magnetic composites coated with parylene via chemical vapor deposition polymerization

    International Nuclear Information System (INIS)

    Wu, Shen; Sun, Aizhi; Lu, Zhenwen; Cheng, Chuan

    2015-01-01

    This paper focuses on novel iron-based soft magnetic composites synthesis utilizing low friction factor parylene C films to coat iron powder via chemical vapor deposition polymerization. The morphology, magnetic properties, density, and chemical stability of parylene insulated iron particles were investigated. The coated parylene insulating layer was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The thickness of parylene C film is averagely 300 nm according to the results of transmission electron microscopy. Parylene C film uniformly coated the powder surface resulting in reducing the permeability imaginary part, increasing electrical resistivity and increasing the operating frequency of the synthesized magnets. It was shown that the parylene C coated compacts exhibited noticeably higher density compared to the epoxy resin coated compacts at the same pressure, suppress at 800 MPa increased the density by 17.02%. The result of Tafel curves indicated that the resistance of the iron particles to corrosion by NaCl solution is obviously improved after being insulated with parylene C film. - Highlights: • Parylene C uniformly coated the powder, increased the operating frequency of SMCs. • Compared with epoxy coated, the density of SMCs increased by 17.02% at 800 MPa. • The resistance of the iron particles is obviously improved with parylene film insulated

  3. Drastic modification of the piezoresistive behavior of polymer nanocomposites by using conductive polymer coatings

    KAUST Repository

    Ventura, Isaac Aguilar; Zhou, Jian; Lubineau, Gilles

    2015-01-01

    We obtained highly conductive nanocomposites by adding conductive polymer poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS)-coated carbon nanotubes (CNTs) to pristine insulating Polycarbonate. Because the PEDOT/PSS ensures efficient charge transfer both along and between the CNTs, we could attribute the improvement in electrical conductivity to coating. In addition to improving the electrical conductivity, the coating also modified the piezoresistive behavior of the nanocomposites compared to the material with pristine uncoated CNTs: whereas CNT/Polycarbonate samples exhibited a very strong piezoresistive effect, PEDOT/PSS-coated MWCNT/Polycarbonate samples exhibited very little piezoresistivity. We studied this change in piezoresistive behavior in detail by investigating various configurations of filler content. We investigated how this observation could be explained by changes in the microstructure and in the conduction mechanism in the interfacial regions between the nanofillers. Our study suggests that tailoring the piezoresistive response to specific application requirements is possible.

  4. Drastic modification of the piezoresistive behavior of polymer nanocomposites by using conductive polymer coatings

    KAUST Repository

    Ventura, Isaac Aguilar

    2015-07-21

    We obtained highly conductive nanocomposites by adding conductive polymer poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS)-coated carbon nanotubes (CNTs) to pristine insulating Polycarbonate. Because the PEDOT/PSS ensures efficient charge transfer both along and between the CNTs, we could attribute the improvement in electrical conductivity to coating. In addition to improving the electrical conductivity, the coating also modified the piezoresistive behavior of the nanocomposites compared to the material with pristine uncoated CNTs: whereas CNT/Polycarbonate samples exhibited a very strong piezoresistive effect, PEDOT/PSS-coated MWCNT/Polycarbonate samples exhibited very little piezoresistivity. We studied this change in piezoresistive behavior in detail by investigating various configurations of filler content. We investigated how this observation could be explained by changes in the microstructure and in the conduction mechanism in the interfacial regions between the nanofillers. Our study suggests that tailoring the piezoresistive response to specific application requirements is possible.

  5. Tribological Behavior of Plasma-Sprayed Al2O3-20 wt.%TiO2 Coating

    Science.gov (United States)

    Cui, Shiyu; Miao, Qiang; Liang, Wenping; Zhang, Zhigang; Xu, Yi; Ren, Beilei

    2017-05-01

    Al2O3-20 wt.% TiO2 ceramic coatings were deposited on the surface of Grade D steel by plasma spraying of commercially available powders. The phases and the microstructures of the coatings were investigated by x-ray diffraction and scanning electron microscopy, respectively. The Al2O3-20 wt.% TiO2 composite coating exhibited a typical inter-lamellar structure consisting of the γ-Al2O3 and the Al2TiO5 phases. The dry sliding wear behavior of the coating was examined at 20 °C using a ball-on-disk wear tester. The plasma-sprayed coating showed a low wear rate ( 4.5 × 10-6 mm3 N-1 m-1), which was matrix ( 283.3 × 10-6 mm3 N-1 m-1), under a load of 15 N. In addition, the tribological behavior of the plasma-sprayed coating was analyzed by examining the microstructure after the wear tests. It was found that delamination of the Al2TiO5 phase was the main cause of the wear during the sliding wear tests. A suitable model was used to simulate the wear mechanism of the coating.

  6. Iron-based soft magnetic composites with Mn-Zn ferrite nanoparticles coating obtained by sol-gel method

    Science.gov (United States)

    Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zhang, Qian; Zhai, Fuqiang; Logan, Philip; Volinsky, Alex A.

    2012-11-01

    This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn-Zn ferrite nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm, were obtained via the sol-gel method. Scanning electron microscopy, energy dispersive X-ray spectroscopy and distribution maps show that the iron particle surface is covered with a thin layer of Mn-Zn ferrites. Mn-Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced imaginary permeability, increased electrical resistivity and a higher operating frequency of the synthesized magnets. Mn-Zn ferrite coated samples have higher permeability and lower magnetic loss when compared with the non-magnetic epoxy resin coated compacts. The real part of permeability increases by 33.5% when compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature on crystalline phase formation and on the magnetic properties of the Mn-Zn ferrite were investigated via X-ray diffraction and a vibrating sample magnetometer. Ferrites decomposed to FeO and MnO after annealing above 400 °C in nitrogen; thus it is the optimum annealing temperature to attain the desired permeability.

  7. Thermally activated, single component epoxy systems

    KAUST Repository

    Unruh, David A.; Pastine, Stefan J.; Moreton, Jessica C.; Frechet, Jean

    2011-01-01

    A single component epoxy system in which the resin and hardener components found in many two-component epoxies are combined onto the same molecule is described. The single molecule precursor to the epoxy resin contains both multiple epoxide moieties and a diamine held latent by thermally degradable carbamate linkages. These bis-carbamate "single molecule epoxies" have an essentially infinite shelf life and access a significant range in curing temperatures related to the structure of the carbamate linkages used. © 2011 American Chemical Society.

  8. Thermally activated, single component epoxy systems

    KAUST Repository

    Unruh, David A.

    2011-08-23

    A single component epoxy system in which the resin and hardener components found in many two-component epoxies are combined onto the same molecule is described. The single molecule precursor to the epoxy resin contains both multiple epoxide moieties and a diamine held latent by thermally degradable carbamate linkages. These bis-carbamate "single molecule epoxies" have an essentially infinite shelf life and access a significant range in curing temperatures related to the structure of the carbamate linkages used. © 2011 American Chemical Society.

  9. Tuning the adhesion between polyimide substrate and MWCNTs/epoxy nanocomposite by surface treatment

    Science.gov (United States)

    Bouhamed, Ayda; Kia, Alireza Mohammadian; Naifar, Slim; Dzhagan, Volodymyr; Müller, Christian; Zahn, Dietrich R. T.; Choura, Slim; Kanoun, Olfa

    2017-11-01

    MWCNTs/epoxy nanocomposite thin films are coated on the polyimide (PI) flexible substrate, to be used as a strain sensor. Previous studies showed that the adhesion between polyimide and other materials are very poor. In this work, two approaches, oxygen plasma cleaning and simple solvent cleaning are performed for activation of the polyimide surface. In order to understand the impact of both cleaning techniques, the physicochemical properties of PI are measured and characterized using contact angle measurements (CAMs), X-ray photoelectron spectroscopy(XPS), and atomic force microscopy (AFM). In addition, the adhesion properties of PI/[MWCNTs/epoxy] systems by varying surface treatment time are investigated and evaluated using force-distance measurements by AFM. The results illustrate that the activated surface exhibits higher surface energy for oxygen plasma cleaning in comparison with the solvent cleaning method. The improvement can be related to the increase of oxygen concentration, which is accompanied by the enhancement of the polar component to 53.79 mN/m due to the formation of functional groups on the surface and the change of the substrate surface roughness from 1.72 nm to 15.5 nm. As a result, improved adhesion was observed from force-distance measurement between PI/[MWCNTs/epoxy] systems due to oxygen plasma effects.

  10. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Cuiqin [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Julin, E-mail: julinwang@126.com [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Tao [Beijing Institute of Ancient Architecture, Beijing 100050 (China)

    2014-12-01

    Graphical abstract: - Highlights: • COOH-CNTs can react with sizing agent, and the optimum reaction ratio was 1:20. • Carbon fibers were dipped into the mixture bath of CNTs and sizing agent. • SEM results indicate that fibers surfaces were coated with CNTs and sizing agent. • ILSS was increased by 67.01% for the composites after the mixture coating process. • Single fibers tensile strength was maintained after the deposited process. - Abstract: The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer.

  11. Mitigating Localized Corrosion Using Thermally Sprayed Aluminum (TSA) Coatings on Welded 25% Cr Superduplex Stainless Steel

    Science.gov (United States)

    Paul, S.; Lu, Q.; Harvey, M. D. F.

    2015-04-01

    Thermally sprayed aluminum (TSA) coating has been increasingly used for the protection of carbon steel offshore structures, topside equipment, and flowlines/pipelines exposed to both marine atmospheres and seawater immersion conditions. In this paper, the effectiveness of TSA coatings in preventing localized corrosion, such as pitting and crevice corrosion of 25% Cr superduplex stainless steel (SDSS) in subsea applications, has been investigated. Welded 25% Cr SDSS (coated and uncoated) with and without defects, and surfaces coated with epoxy paint were also examined. Pitting and crevice corrosion tests, on welded 25% Cr SDSS specimens with and without TSA/epoxy coatings, were conducted in recirculated, aerated, and synthetic seawater at 90 °C for 90 days. The tests were carried out at both the free corrosion potentials and an applied cathodic potential of -1100 mV saturated calomel electrode. The acidity (pH) of the test solution was monitored daily and adjusted to between pH 7.5 and 8.1, using dilute HCl solution or dilute NaOH, depending on the pH of the solution measured during the test. The test results demonstrated that TSA prevented pitting and crevice corrosion of 25% Cr SDSS in artificial seawater at 90 °C, even when 10-mm-diameter coating defect exposing the underlying steel was present.

  12. Comparative study on structure, corrosion properties and tribological behavior of pure Zn and different Zn-Ni alloy coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tafreshi, M. [Department of Metallurgy and Materials Engineering, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Allahkaram, S.R., E-mail: akaram@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O.Box: 11155-4563, Tehran (Iran, Islamic Republic of); Farhangi, H. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O.Box: 11155-4563, Tehran (Iran, Islamic Republic of)

    2016-11-01

    Zn and Zn-Ni alloy coatings were electrodeposited from sulfate based electrolytes. The effect of alloys Ni content on morphology, microstructure, corrosion properties, microhardness and tribological behavior of these coatings were investigated and the results were compared with Zn film. According to X-ray diffraction patterns, different intermediate phases (η-Ni{sub 3}Zn{sub 22}, γ-Ni{sub 5}Zn{sub 21}, β-Zn-Ni) were formed by increasing the coatings Ni content from 11 to 17 wt%. Polarization and EIS results revealed that all the alloy coatings had better corrosion resistance than the Zn film. Zn-14 wt%Ni coating had the least corrosion current density and maximum polarization resistance between all the samples. Microhardness of the coatings was improved by increasing their Ni percentage to 17%. However, Zn-14 wt%Ni coating had the lowest wear loss and friction coefficient, while Zn film had the worst wear resistance between all the coatings. - Highlights: • Effect of Ni alloying element on morphology and structure of Zn electrodeposits. • Comparing corrosion behavior of Zn and Zn-Ni coatings. • Influence of Ni content on hardness of Zn-Ni films. • A comparison of tribological behavior of Zn and different Zn-Ni electrodeposits.

  13. Synthesis and electrical characterization of low-temperature thermal-cured epoxy resin/functionalized silica hybrid-thin films for application as gate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Na, Moonkyong, E-mail: nmk@keri.re.kr [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); System on Chip Chemical Process Research Center, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 (Korea, Republic of); Kang, Young Taec [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Department of Polymer Science and Engineering, Pusan National University, Busan, 609-735 (Korea, Republic of); Kim, Sang Cheol [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Kim, Eun Dong [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of)

    2013-07-31

    Thermal-cured hybrid materials were synthesized from homogenous hybrid sols of epoxy resins and organoalkoxysilane-functionalized silica. The chemical structures of raw materials and obtained hybrid materials were characterized using Fourier transform infrared spectroscopy. The thermal resistance of the hybrids was enhanced by hybridization. The interaction between epoxy matrix and the silica particles, which caused hydrogen bonding and van der Waals force was strengthened by organoalkoxysilane. The degradation temperature of the hybrids was improved by approximately 30 °C over that of the parent epoxy material. The hybrid materials were formed into uniformly coated thin films of about 50 nm-thick using a spin coater. An optimum mixing ratio was used to form smooth-surfaced hybrid films. The electrical property of the hybrid film was characterized, and the leakage current was found to be well below 10{sup −6} A cm{sup −2}. - Highlights: • Preparation of thermal-curable hybrid materials using epoxy resin and silica. • The thermal stability was enhanced through hybridization. • The insulation property of hybrid film was investigated as gate dielectrics.

  14. Remarkable weakness against cleavage stress for YBCO-coated conductors and its effect on the YBCO coil performance

    International Nuclear Information System (INIS)

    Yanagisawa, Y.; Nakagome, H.; Takematsu, T.; Takao, T.; Sato, N.; Takahashi, M.; Maeda, H.

    2011-01-01

    Cleavage strength for YBCO-coated conductor is extremely low, typically 0.5 MPa. The remarkable weakness is due to cracks on the slit edge of the conductor. The cleavage stress appears on YBCO double pancake coils impregnated with epoxy. The cleavage stress should be avoided in the coil winding. Cleavage strength for an YBCO-coated conductor at 77 K was investigated with a model experiment. The nominal cleavage strength for an YBCO-coated conductor is extremely low, typically 0.5 MPa. This low nominal cleavage strength is due to stress concentration on a small part of the YBCO-coated conductor in cleavage fracture. Debonding by the cleavage stress occurs at the interface between the buffer layer and the Hastelloy substrate. The nominal cleavage strength for a slit edge of the conductor is 2.5-times lower than that for the original edge of the conductor; cracks and micro-peel existing over the slit edge reduce the cleavage strength for the slit edge. Cleavage stress and peel stress should be avoided in coil winding, as they easily delaminate the YBCO-coated conductor, resulting in substantial degradation of coil performance. These problems are especially important for epoxy impregnated YBCO-coated conductor coils. It appears that effect of cleavage stress and peel stress are mostly negligible for paraffin impregnated YBCO-coated conductor coils or dry wound YBCO-coated conductor coils.

  15. Rate-dependent mode I interlaminar crack growth mechanisms in graphite/epoxy and graphite/PEEK

    Science.gov (United States)

    Gillespie, J. W., Jr.; Carlsson, L. A.; Smiley, A. J.

    1987-01-01

    In this paper the mode I fracture behavior of graphite/epoxy and graphite/PEEK composites is examined over four decades of crosshead rates (0.25-250 mm/min). Straight-sided double-cantilever-beam specimens consisting of unidirectional laminates were tested at room temperature. For graphite/epoxy the load-deflection response was linear to fracture, and stable slow crack growth initiating at the highest load level was observed for all rates tested. In contrast, mode I crack growth in the graphite/PEEK material was often unstable and showed stick-slip behavior. Subcritical crack growth occurring prior to the onset of fracture was observed at intermediate displacement rates. A mechanism for the fracture behavior of the graphite/PEEK material (based on viscoelastic, plastic, and microcrack coalescence in the process zone) is proposed and related to the observed rate-dependent phenomena.

  16. Mechanical Properties of Graphene Nanoplatelet/Carbon Fiber/Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, C. M.; Klimek-McDonald, D. R.; Pineda, E. J.; King, J. A.; Reichanadter, A. M.; Miskioglu, I.; Gowtham, S.; Odegard, G. M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  17. Mechanical Properties of Graphene Nanoplatelet Carbon Fiber Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, Cameron M.; Klimek-McDonald, Danielle R.; Pineda, Evan J.; King, Julie A.; Reichanadter, Alex M.; Miskioglu, Ibrahim; Gowtham, S.; Odegard, Gregory M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  18. Improved Dielectric Properties and Energy Storage Density of Poly(vinylidene fluoride-co-hexafluoropropylene) Nanocomposite with Hydantoin Epoxy Resin Coated BaTiO3.

    Science.gov (United States)

    Luo, Hang; Zhang, Dou; Jiang, Chao; Yuan, Xi; Chen, Chao; Zhou, Kechao

    2015-04-22

    Energy storage materials are urgently demanded in modern electric power supply and renewable energy systems. The introduction of inorganic fillers to polymer matrix represents a promising avenue for the development of high energy density storage materials, which combines the high dielectric constant of inorganic fillers with supernal dielectric strength of polymer matrix. However, agglomeration and phase separation of inorganic fillers in the polymer matrix remain the key barriers to promoting the practical applications of the composites for energy storage. Here, we developed a low-cost and environmentally friendly route to modifying BaTiO3 (BT) nanoparticles by a kind of water-soluble hydantoin epoxy resin. The modified BT nanoparticles exhibited homogeneous dispersion in the ferroelectric polymer poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix and strong interfacial adhesion with the polymer matrix. The dielectric constants of the nanocomposites increased significantly with the increase of the coated BT loading, while the dielectric loss of the nanocomposites was still as low as that of the pure P(VDF-HFP). The energy storage density of the nanocomposites was largely enhanced with the coated BT loading at the same electric field. The nanocomposite with 20 vol % BT exhibited an estimated maximum energy density of 8.13 J cm(-3), which was much higher than that of pure P(VDF-HFP) and other dielectric polymers. The findings of this research could provide a feasible approach to produce high energy density materials for practical application in energy storage.

  19. AC and DC electrical behavior of MWCNT/epoxy nanocomposite near percolation threshold: Equivalent circuits and percolation limits

    Science.gov (United States)

    Alizadeh Sahraei, Abolfazl; Ayati, Moosa; Baniassadi, Majid; Rodrigue, Denis; Baghani, Mostafa; Abdi, Yaser

    2018-03-01

    This study attempts to comprehensively investigate the effects of multi-walled carbon nanotubes (MWCNTs) on the AC and DC electrical conductivity of epoxy nanocomposites. The samples (0.2, 0.3, and 0.5 wt. % MWCNT) were produced using a combination of ultrason and shear mixing methods. DC measurements were performed by continuous measurement of the current-voltage response and the results were analyzed via a numerical percolation approach, while for the AC behavior, the frequency response was studied by analyzing phase difference and impedance in the 10 Hz to 0.2 MHz frequency range. The results showed that the dielectric parameters, including relative permittivity, impedance phase, and magnitude, present completely different behaviors for the frequency range and MWCNT weight fractions studied. To better understand the nanocomposites electrical behavior, equivalent electric circuits were also built for both DC and AC modes. The DC equivalent networks were developed based on the current-voltage curves, while the AC equivalent circuits were proposed by using an optimization problem according to the impedance magnitude and phase at different frequencies. The obtained equivalent electrical circuits were found to be highly useful tools to understand the physical mechanisms involved in MWCNT filled polymer nanocomposites.

  20. Correlation between Mechanical Properties with Specific Wear Rate and the Coefficient of Friction of Graphite/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Mahdi Alajmi

    2015-07-01

    Full Text Available The correlation between the mechanical properties of Fillers/Epoxy composites and their tribological behavior was investigated. Tensile, hardness, wear, and friction tests were conducted for Neat Epoxy (NE, Graphite/Epoxy composites (GE, and Data Palm Fiber/Epoxy with or without Graphite composites (GFE and FE. The correlation was made between the tensile strength, the modulus of elasticity, elongation at the break, and the hardness, as an individual or a combined factor, with the specific wear rate (SWR and coefficient of friction (COF of composites. In general, graphite as an additive to polymeric composite has had an eclectic effect on mechanical properties, whereas it has led to a positive effect on tribological properties, whilst date palm fibers (DPFs, as reinforcement for polymeric composite, promoted a mechanical performance with a slight improvement to the tribological performance. Statistically, this study reveals that there is no strong confirmation of any marked correlation between the mechanical and the specific wear rate of filler/Epoxy composites. There is, however, a remarkable correlation between the mechanical properties and the friction coefficient of filler/Epoxy composites.

  1. Correlation between Mechanical Properties with Specific Wear Rate and the Coefficient of Friction of Graphite/Epoxy Composites.

    Science.gov (United States)

    Alajmi, Mahdi; Shalwan, Abdullah

    2015-07-08

    The correlation between the mechanical properties of Fillers/Epoxy composites and their tribological behavior was investigated. Tensile, hardness, wear, and friction tests were conducted for Neat Epoxy (NE), Graphite/Epoxy composites (GE), and Data Palm Fiber/Epoxy with or without Graphite composites (GFE and FE). The correlation was made between the tensile strength, the modulus of elasticity, elongation at the break, and the hardness, as an individual or a combined factor, with the specific wear rate (SWR) and coefficient of friction (COF) of composites. In general, graphite as an additive to polymeric composite has had an eclectic effect on mechanical properties, whereas it has led to a positive effect on tribological properties, whilst date palm fibers (DPFs), as reinforcement for polymeric composite, promoted a mechanical performance with a slight improvement to the tribological performance. Statistically, this study reveals that there is no strong confirmation of any marked correlation between the mechanical and the specific wear rate of filler/Epoxy composites. There is, however, a remarkable correlation between the mechanical properties and the friction coefficient of filler/Epoxy composites.

  2. Steady-shear rheological properties of graphene-reinforced epoxy resin for manufacturing of aerospace composite films

    Science.gov (United States)

    Clausi, Marialaura; Santonicola, M. Gabriella; Laurenzi, Susanna

    2016-05-01

    The aim of this work is to analyze the steady-shear rheological behavior and the absolute viscosity of epoxy matrix reinforced with graphene nanoplatelets (xGnP) before cure. Three different grades of xGnP (grades C, M and H) were dispersed homogenously at different weight percentages (wt%) into the epoxy matrix, ranging from 0.5 to 5 wt%. It is found that nanocomposite fluids with xGnP-C exhibit a Newtonian behavior at shear rate in the range 0.1-100 s-1, conversely, nanocomposite fluids with xGnP of grade M and H exhibit a shear-thinning behavior with the increase of nanoplatelet loading. Results from this analysis indicate how the steady shear rheological properties of the nano-reinforced polymer fluids depend on the geometrical characteristics of the graphene nanoplatelets.

  3. Effects of molybdenum dithiocarbamate and zinc dialkyl dithiophosphate additives on tribological behaviors of hydrogenated diamond-like carbon coatings

    International Nuclear Information System (INIS)

    Yue, Wen; Liu, Chunyue; Fu, Zhiqiang; Wang, Chengbiao; Huang, Haipeng; Liu, Jiajun

    2014-01-01

    Highlights: • For MoDTC, DLC coating showed better anti-friction and worse anti-wear behaviors. • The improved anti-friction property was due to graphitization and MoS 2 . • Formation of MoO x resulted in a high wear volume. • For ZDDP, DLC coating showed the best anti-wear and the worst anti-friction behaviors. • Absence of friction reducing product and graphitized layer resulted in a higher friction. - Abstract: The tribological behaviors of hydrogenated diamond-like carbon (DLC) coatings under varied load conditions lubricated with polyalpha olefin (PAO), molybdenum dithiocarbamate (MoDTC) and zinc dialkyl dithiophosphate (ZDDP) additives were investigated in this paper. Hydrogenated DLC coatings were synthesized through the decomposition of acetylene by the ion source. The tribological performances were measured on a SRV tribometer. The morphologies and chemical structures of the DLC coatings were investigated by the scanning electron microscope (SEM), Raman spectrometer (Raman) and X-ray photoelectron spectroscope (XPS). It was shown that the low friction and high wear were achieved on the hydrogenated DLC coating under MoDTC lubrication, while low wear was found on the hydrogenated DLC coating lubricated by ZDDP. The primary reason was attributed to different tribofilms formed on the contact area and the formation of graphitic layer. Both factors working together leaded to quite different tribological behaviors

  4. Degradation Behavior of Epoxy Resins in Fibre Metal Laminates Under Thermal Conditions

    NARCIS (Netherlands)

    Zhu, G.; Xiao, Y.; Yang, Y.; Wang, J.; Sun, B.; Boom, R.

    2012-01-01

    GLARE (glass fibre/epoxy reinforced aluminum laminate) is a member of the fiber metal laminate (FML) family, and is built up of alternating metal and fiber layers. About 500m2 GLARE is employed in each Airbus A380 because of the superior mechanical properties over the monolithic aluminum alloys,

  5. Zirconium tungstate/epoxy nanocomposites: effect of nanoparticle morphology and negative thermal expansivity.

    Science.gov (United States)

    Wu, Hongchao; Rogalski, Mark; Kessler, Michael R

    2013-10-09

    The ability to tailor the coefficient of thermal expansion (CTE) of a polymer is essential for mitigating thermal residual stress and reducing microcracks caused by CTE mismatch of different components in electronic applications. This work studies the effect of morphology and thermal expansivity of zirconium tungstate nanoparticles on the rheological, thermo-mechanical, dynamic-mechanical, and dielectric properties of ZrW2O8/epoxy nanocomposites. Three types of ZrW2O8 nanoparticles were synthesized under different hydrothermal conditions and their distinct properties were characterized, including morphology, particle size, aspect ratio, surface area, and CTE. Nanoparticles with a smaller particle size and larger surface area led to a more significant reduction in gel-time and glass transition temperature of the epoxy nanocomposites, while a higher initial viscosity and significant shear thinning behavior was found in prepolymer suspensions containing ZrW2O8 with larger particle sizes and aspect ratios. The thermo- and dynamic-mechanical properties of epoxy-based nanocomposites improved with increasing loadings of the three types of ZrW2O8 nanoparticles. In addition, the introduced ZrW2O8 nanoparticles did not negatively affect the dielectric constant or the breakdown strength of the epoxy resin, suggesting potential applications of ZrW2O8/epoxy nanocomposites in the microelectronic insulation industry.

  6. High Temperature Epoxy Foam: Optimization of Process Parameters

    Directory of Open Access Journals (Sweden)

    Samira El Gazzani

    2016-06-01

    Full Text Available For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

  7. Anticoagulation and endothelial cell behaviors of heparin-loaded graphene oxide coating on titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Chang-Jiang, E-mail: panchangjiang@hyit.edu.cn [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China); Pang, Li-Qun [Department of General Surgery, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an 223300 (China); Gao, Fei [Zhejiang Zylox Medical Devices Co., Ltd., Hangzhou 310000 (China); Wang, Ya-Nan; Liu, Tao; Ye, Wei; Hou, Yan-Hua [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China)

    2016-06-01

    Owing to its unique physical and chemical properties, graphene oxide (GO) has attracted tremendous interest in many fields including biomaterials and biomedicine. The purpose of the present study is to investigate the endothelial cell behaviors and anticoagulation of heparin-loaded GO coating on the titanium surface. To this end, the titanium surface was firstly covered by the polydopamine coating followed by the deposition of the GO coating. Heparin was finally loaded on the GO coating to improve the blood compatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that the heparin-loaded GO coating was successfully created on the titanium surface. The scanning electron microscopy (SEM) images indicated that a relative uniform GO coating consisting of multilayer GO sheets was formed on the substrate. The hydrophilicity of the titanium surface was enhanced after the deposition of GO and further improved significantly by the loading heparin. The GO coating can enhance the endothelial cell adhesion and proliferation as compared with polydopamine coating and the blank titanium. Loading heparin on the GO coating can significantly reduce the platelet adhesion and prolong the activated partial thromboplastin time (APTT) while not influence the endothelial cell adhesion and proliferation. Therefore, the heparin-loaded GO coating can simultaneously enhance the cytocompatibility to endothelial cells and blood compatibility of biomaterials. Because the polydopamine coating can be easily prepared on most of biomaterials including polymer, ceramics and metal, thus the approach of the present study may open up a new window of promising an effective and efficient way to promote endothelialization and improve the blood compatibility of blood-contact biomedical devices such as intravascular stents. - Highlights: • Heparin-loaded graphene oxide coating was

  8. Development of radioactive standards in epoxy matrix for the control of quality of activimeters; Desenvolvimento de padroes radioativos em matriz epoxi para controle da qualidade de ativimetros

    Energy Technology Data Exchange (ETDEWEB)

    Fragoso, Maria da Conceicao de Farias; Monteiro, Luciane Carollyne de Oliveira Reis; Oliveira, Marcia Liane de, E-mail: mcfragoso@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE), Recife, PE (Brazil)

    2016-07-01

    In the present study, a new approach for development of the standards for positron emitting radionuclides in epoxy matrix is presented. Different formulations were prepared using epoxy resin (bisphenol A diglycidyl ether - DGEBA) and curing agents, to immobilize the radioactive material. The efficiency curve and standard sample methods were applied for activity determination of a long-lived positron emitter ({sup 22}Na). Satisfactory results were obtained in the 3{sup rd} combination. Thus, these radioactive standards can be used to evaluate the metrological behavior of the systems used for the measurement of the radiopharmaceuticals (activimeters) in the production centers and in nuclear medicine services. (author)

  9. Characterization of Epoxy Functionalized Graphite Nanoparticles and the Physical Properties of Epoxy Matrix Nanocomposites

    Science.gov (United States)

    Miller, Sandi G.; Bauer, Jonathan L.; Maryanski, Michael J.; Heimann, Paula J.; Barlow, Jeremy P.; Gosau, Jan-Michael; Allred, Ronald E.

    2010-01-01

    This work presents a novel approach to the functionalization of graphite nanoparticles. The technique provides a mechanism for covalent bonding between the filler and matrix, with minimal disruption to the sp2 hybridization of the pristine graphene sheet. Functionalization proceeded by covalently bonding an epoxy monomer to the surface of expanded graphite, via a coupling agent, such that the epoxy concentration was measured as approximately 4 wt.%. The impact of dispersing this material into an epoxy resin was evaluated with respect to the mechanical properties and electrical conductivity of the graphite-epoxy nanocomposite. At a loading as low as 0.5 wt.%, the electrical conductivity was increased by five orders of magnitude relative to the base resin. The material yield strength was increased by 30% and Young s modulus by 50%. These results were realized without compromise to the resin toughness.

  10. Simultaneous acid exposure and erosive particle wear of thermoset coatings

    DEFF Research Database (Denmark)

    Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria

    2018-01-01

    , similar to the erosion/corrosion-type phenomena found in metals. A vinyl ester-based coating was the most resistant to the simultaneous erosive/acidic exposure, with a maximum polishing rate of 3.24±0.61 μm/week, while novolac epoxy and polyurethane coatings showed high polishing rates of 11.7±1.50 and 13.4±0......Handling acidic chemicals is a challenge in the chemical industry, requiring a careful choice of contact material. Certain thermoset organic coatings are applicable in low pH environments, but when particulate erosion is also present the performance demand is increased. This is the case in, e...

  11. Electrochemical behavior of single layer CrN, TiN, TiAlN coatings and nanolayered TiAlN/CrN multilayer coatings prepared by reactive direct current magnetron sputtering

    International Nuclear Information System (INIS)

    William Grips, V.K.; Barshilia, Harish C.; Selvi, V. Ezhil; Kalavati; Rajam, K.S.

    2006-01-01

    The corrosion behaviors of single layer TiN, CrN, TiAlN and multilayer TiAlN/CrN coatings, deposited on steel substrate using a multi-target reactive direct current magnetron sputtering process, were studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The total thickness of the coatings was about 1.5 μm. About 0.5 μm thick chromium interlayer was used for improved adhesion of the coatings. The potentiodynamic polarization measurements showed that for all the coatings the corrosion potential shifted to higher values as compared to the uncoated substrate. Similarly, the corrosion current density decreased for coated samples, indicating better corrosion resistance of the coated samples. The multilayer coatings of TiAlN/CrN exhibited superior corrosion behavior as compared to the single layer coatings. The Nyquist and the Bode plots obtained from the EIS measurements were fitted by appropriate equivalent circuits to calculate the pore resistance, the charge transfer resistance and the capacitance. These studies revealed that the pore resistance was lowest for TiN coatings, which increased for TiAlN coatings. TiAlN/CrN multilayer coatings exhibited highest pore resistance. No significant change in the capacitive behavior of the coatings was observed, suggesting minimal morphological changes as a result of immersion in the electrolyte. This could be attributed to shorter immersion durations. These studies were confirmed by examining the corroded samples under scanning electron microscope. Preliminary experiments conducted with additional interlayer of electroless nickel (5.0 μm thick) have shown significant improvement in the corrosion resistance of the coatings

  12. Microstructure and Wear Behavior of Atmospheric Plasma-Sprayed AlCoCrFeNiTi High-Entropy Alloy Coating

    Science.gov (United States)

    Tian, Li-Hui; Xiong, Wei; Liu, Chuan; Lu, Sheng; Fu, Ming

    2016-12-01

    Due to the advantages such as high strength, high hardness and good wear resistance, high-entropy alloys (HEAs) attracted more and more attentions in recent decades. However, most reports on HEAs were limited to bulk materials. Although a few of studies on atmospheric plasma-sprayed (APS) HEA coatings were carried out, the wear behavior, especially the high-temperature wear behavior of those coatings has not been investigated till now. Therefore, in this study, APS was employed to deposit AlCoCrFeNiTi high-entropy alloy coating using mechanically alloyed AlCoCrFeNiTi powder as the feedstock. The phase structure of the initial powder, the feedstock powder and the as-sprayed coating was examined by an x-ray diffractometer. The surface morphology of the feedstock powder and the microstructure of the as-sprayed coating were analyzed by field emission scanning electron microscopy and energy-dispersive spectroscopy. The bonding strength and the microhardness of the as-sprayed coating were tested. The wear behavior of the coating at 25, 500, 700 and 900 °C was investigated by analysis of the wear surface morphology and measurements of the volume wear rate and the coefficient of friction.

  13. Cathodic disbonding of organic coatings on submerged steel

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Ole oeystein

    1998-12-31

    In offshore oil production, submerged steel structures are commonly protected by an organic coating in combination with cathodic protection. The main advantage is that the coating decreases the current demand for cathodic protection. But the coating degrades with time. This thesis studies one of the most important mechanisms for coating degradation in seawater, cathodic disbonding. Seven commercial coatings and two model coatings with various pigmentations have been studied. Parameter studies, microscopy and studies of free films were used in the mechanism investigations. Exposure to simulated North Sea conditions was used in the performance studies. The effect of aluminium and glass barrier pigments on cathodic disbonding was investigated. The mechanism for the effect of the aluminium pigments on cathodic disbonding was also investigated. The transport of charge and oxygen to the steel/coating interface during cathodic disbonding was studied for two epoxy coatings. Cathodic disbonding, blistering and current demand for cathodic protection was measured for nine commercial coatings for submerged steel structures, using the ASTM-G8 standard test and a long term test under simulated North Sea conditions. The relevance of the ASTM-G8 test as a prequalification test was evaluated. 171 refs., 40 figs., 6 tabs.

  14. Oxidation behavior of Hf-modified platinum aluminide coatings during thermal cycling

    Directory of Open Access Journals (Sweden)

    Liya Ye

    2018-02-01

    Full Text Available Platinum aluminide coatings with different Hf contents were fabricated by using HfCl4. The oxidation kinetics and the rumpling behavior of oxide scale were investigated. After thermal cycling, the coating with 0.46 wt% Hf showed least weight gain. With the increase of Hf content, rumpling extent of the scale decreased. Meanwhile, HfO2 preferentially formed in the scale resulting in the increase of scale thickness. The oxidation of excessive Hf even caused the spallation of the scale. The results in the present study indicate that although Hf plays an important role in decreasing rumpling extent of TGO, the oxidation of Hf decreases the adhesion of the scale. Keywords: Pt-Al coating, Hf, Oxidation, Rumpling

  15. Assessment of Automotive Coatings Used on Different Metallic Substrates

    Directory of Open Access Journals (Sweden)

    W. Bensalah

    2014-01-01

    Full Text Available Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of different coating systems were conducted using pin on disc machine. Immersion tests were carried out in 5% NaCl and immersion tests in 3% NaOH solutions. Results showed which of the coating systems is more suitable for each substrate in terms of mechanical, tribological, and anticorrosive performance.

  16. Comparison of Corrosion Behavior of Electrochemically Deposited Nano-Cobalt-Coated Ni Sheet

    Directory of Open Access Journals (Sweden)

    Nasser Al-Aqeeli

    2013-01-01

    Full Text Available Corrosion behavior of nano-coblat-coated Ni sheet was compared with pure Ni and 20% Fe-Ni alloy sheet using potentiodynamic polarization and linear polarization technique in 0.1 M NaCl solution at room temperature. Results showed that corrosion resistance properties of nano-Co-coated Ni sheet were almost same as that of pure Ni sheet, however corrosion resistance of 20% Fe-Ni sheet was decreased significantly. Pitting potential of 20% Fe-Ni sheet was subsequently decreased as compared to pure Ni sheet as well as nano-cobalt-coated Ni sheet. SEM/EDS analysis of the corroded surfaces showed that both pure Ni and nano-coblat-coated Ni sheet did not show any appreciable corrosion however significant corrosion was observed in the case of 20% Fe-Ni sheet.

  17. Oxidation Behavior of Titanium Carbonitride Coating Deposited by Atmospheric Plasma Spray Synthesis

    Science.gov (United States)

    Zhu, Lin; He, Jining; Yan, Dianran; Liao, Hanlin; Zhang, Nannan

    2017-10-01

    As a high-hardness and anti-frictional material, titanium carbonitride (TiCN) thick coatings or thin films are increasingly being used in many industrial fields. In the present study, TiCN coatings were obtained by atmospheric plasma spray synthesis or reactive plasma spray. In order to promote the reaction between the Ti particles and reactive gases, a home-made gas tunnel was mounted on a conventional plasma gun to perform the spray process. The oxidation behavior of the TiCN coatings under different temperatures in static air was carefully investigated. As a result, when the temperature was over 700 °C, the coatings suffered from serious oxidation, and finally they were entirely oxidized to the TiO2 phase at 1100 °C. The principal oxidation mechanism was clarified, indicating that the oxygen can permeate into the defects and react with TiCN at high temperatures. In addition, concerning the use of a TiCN coating in high-temperature conditions, the microhardness of the oxidized coatings at different treatment temperatures was also evaluated.

  18. Corrosion and Wear Behaviors of Cr-Doped Diamond-Like Carbon Coatings

    Science.gov (United States)

    Viswanathan, S.; Mohan, L.; Bera, Parthasarathi; Kumar, V. Praveen; Barshilia, Harish C.; Anandan, C.

    2017-08-01

    A combination of plasma-enhanced chemical vapor deposition and magnetron sputtering techniques has been employed to deposit chromium-doped diamond-like carbon (DLC) coatings on stainless steel, silicon and glass substrates. The concentrations of Cr in the coatings are varied by changing the parameters of the bipolar pulsed power supply and the argon/acetylene gas composition. The coatings have been studied for composition, morphology, surface nature, nanohardness, corrosion resistance and wear resistance properties. The changes in I D / I G ratio with Cr concentrations have been obtained from Raman spectroscopy studies. Ratio decreases with an increase in Cr concentration, and it has been found to increase at higher Cr concentration, indicating the disorder in the coating. Carbide is formed in Cr-doped DLC coatings as observed from XPS studies. There is a decrease in sp 3/ sp 2 ratios with an increase in Cr concentration, and it increases again at higher Cr concentration. Nanohardness studies show no clear dependence of hardness on Cr concentration. DLC coatings with lower Cr contents have demonstrated better corrosion resistance with better passive behavior in 3.5% NaCl solution, and corrosion potential is observed to move toward nobler (more positive) values. A low coefficient of friction (0.15) at different loads is observed from reciprocating wear studies. Lower wear volume is found at all loads on the Cr-doped DLC coatings. Wear mechanism changes from abrasive wear on the substrate to adhesive wear on the coating.

  19. Ablation behavior of rare earth La-modified ZrC coating for SiC-coated carbon/carbon composites under an oxyacetylene torch

    International Nuclear Information System (INIS)

    Jia, Yujun; Li, Hejun; Feng, Lei; Sun, Jiajia; Li, Kezhi; Fu, Qiangang

    2016-01-01

    Highlights: • La-modified ZrC coating was prepared by supersonic atmosphere plasma spraying. • The oxyacetylene ablation behavior of La-modified ZrC/SiC coating was evaluated. • The coating shows a good ablation resistance under heat flux of 2.4 MW/m"2. • La promotes the liquid phase sintering of ZrO_2 and the formation of a compact scale. • The protection of the scale results in retaining elemental C in its inner layer. - Abstract: To improve the ablation resistance of carbon/carbon (C/C) composites at ultra-high temperature, La-modified ZrC coating was prepared on SiC-coated C/C composites by supersonic atmosphere plasma spraying. The coating shows a significant improvement on the ablation resistance compared with ZrC coating and could protect C/C composites for more than 120 s under heat flux of 2.4 MW/m"2. La acted as a role in promoting the liquid phase sintering of ZrO_2 and forming a compact scale with high thermal stability, improving the ablation resistance of C/C composites.

  20. Corrosion Performance of Nano-ZrO₂ Modified Coatings in Hot Mixed Acid Solutions.

    Science.gov (United States)

    Xu, Wenhua; Wang, Zhenyu; Han, En-Hou; Wang, Shuai; Liu, Qian

    2018-06-01

    A nano-ZrO₂ modified coating system was prepared by incorporation of nano-ZrO₂ concentrates into phenolic-epoxy resin. The corrosion performance of the coatings was evaluated in hot mixed acid solution, using electrochemical methods combined with surface characterization, and the effects of nano-ZrO₂ content were specially focused on. The results showed that 1% and 3% nano-ZrO₂ addition enhanced the corrosion resistance of the coatings, while 5% nano-ZrO₂ addition declined it. The coating with 3% nano-ZrO₂ presented the minimum amount of species diffusion, the lowest average roughness (5.94 nm), and the highest C/O ratio (4.55) and coating resistance, and it demonstrated the best corrosion performance among the coating specimens.

  1. Carbon black reinforced C8 ether linked bismaleimide toughened electrically conducting epoxy nanocomposites

    International Nuclear Information System (INIS)

    Mandhakini, M.; Chandramohan, A.; Jayanthi, K.; Alagar, M.

    2014-01-01

    Highlight: • The toughness of the epoxy is improved with C8e-BMI. • Conduction through ohmic contact chain takes the leading mechanism for electrical conduction instead of tunneling with 5 wt% CB. • The phase segregation between epoxy/C8 e-BMI improves the toughness of the nanocomposite. • Both toughening and flexibilization effect is responsible for improvement in impact strength. • The largest challenge of appropriate balance between the electrical conductivity and mechanical behavior is attained in a cost effective manner. - Abstract: The present work deals with the toughening of brittle epoxy matrix with C8 ether linked bismaleimide (C8 e-BMI) and then study the reinforcing effect of carbon black (CB) in enhancing the conducting properties of insulating epoxy matrix. The Fourier transform infrared spectroscopy (FTIR) and Raman analysis indicate the formation of strong covalent bonds between CB and C8 e-BMI/epoxy matrix. The X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) analysis indicate the event of phase separation in 5 wt% CB loaded epoxy C8 e-BMI nanocomposites. The impact strength increased up to 5 wt% of CB loading with particle pull and crack deflection to be driving mechanism for enhancing the toughness of the nanocomposite and beyond 5 wt% the impact strength started to decrease due to aggregation of CB. The dynamic mechanical analysis (DMA) also indicates the toughness of the nanocomposites was improved with 5 wt% of CB loading due to the phase segregation between epoxy and C8 e-BMI in the presence of CB. The electrical conductivity was also increased with 5 wt% of CB due to classical conduction by ohmic chain contact

  2. Novel coating compositions

    International Nuclear Information System (INIS)

    Kimura, Tadashi; Kobayashi, Juichi; Nakamoto, Hideo.

    1969-01-01

    An acrylic coating composition rapidly hardenable by irradiating with ionizing radiations or light beams is given using hydroxyl group-containing vinyl monomers, polycarboxylic acid anhydrides, epoxy group-containing vinyl monomers and an organic solvent having a boiling point of at least 120 0 C. The process comprises the steps of first and second reactions. The first reaction takes place between one mol of a hydroxyl group of a basic polymer and at least 0.1 mol of polycarboxylic acid anhydride, wherein the basic polymer has a molecular weight ranging from 5,000 to 100,000 and consists of 1-40% by weight of vinyl monomer containing hydroxyl group, at least 30% of (meth)acrylic monomer and other vinyl monomers if required. The second reaction takes place between one mol of hydroxyl plus a carboxyl group of the thus obtained basic polymer and at least 0.1 mol of an epoxy group-containing vinyl monomer to produce a prepolymer. The prepolymer is mixed with a solvent such as ethyl benzene to produce the coating material. The electron beam accelerator energy level may be 0.1-2.0 MeV. In light beam polymerization, benzoin is particularly utilized as an intensifying substance. In one example, a basic polymer is produced by reacting 39 parts of styrene, 37 parts of ethyl acrylate, 24 parts of 2-hydroxyl ethyl acrylate, 4 parts of dimethyl amino ethyl methacrylate and others. A prepolymer is produced by reacting this basic polymer with 30 parts of glycidyl acrylate and others. (Iwakiri, K.)

  3. Influence of the reaction stoichiometry on the mechanical and thermal properties of SWCNT-modified epoxy composites

    International Nuclear Information System (INIS)

    Ashrafi, Behnam; Johnston, Andrew; Martinez-Rubi, Yadienka; Kingston, Christopher T; Simard, Benoit; Khoun, Lolei; Yourdkhani, Mostafa; Hubert, Pascal

    2013-01-01

    Previous studies suggest that carbon nanotubes (CNTs) have a considerable influence on the curing behavior and crosslink density of epoxy resins. This invariably has an important effect on different thermal and mechanical properties of the epoxy network. This work focuses on the important role of the epoxy/hardener mixing ratio on the mechanical and thermal properties of a high temperature aerospace-grade epoxy (MY0510 Araldite as an epoxy and 4,4′-diaminodiphenylsulfone as an aromatic hardener) modified with single-walled carbon nanotubes (SWCNTs). The effects of three different stoichiometries (stoichiometric and off-stoichiometric) on various mechanical and thermal properties (fracture toughness, tensile properties, glass transition temperature) of the epoxy resin and its SWCNT-modified composites were obtained. The results were also supported by Raman spectroscopy and scanning electron microscopy (SEM). For the neat resin, it was found that an epoxy/hardener molar ratio of 1:0.8 provides the best overall properties. In contrast, the pattern in property changes with the reaction stoichiometry was considerably different for composites reinforced with unfunctionalized SWCNTs and reduced SWCNTs. A comparison among composites suggests that a 1:1 molar ratio considerably outperforms the other two ratios examined in this work (1:0.8 and 1:1.1). This composition at 0.2 wt% SWCNT loading provides the highest overall mechanical properties by improving fracture toughness, ultimate tensile strength and ultimate tensile strain of the epoxy resin by 40%, 34%, 54%, respectively. (paper)

  4. Tribological Behavior of Coating Cr Layer on 40Cr after Surface Electron Beam Pretreatment

    Science.gov (United States)

    Hu, J. J.; Wang, J.; Jiang, P.; Xu, H. B.; Li, H.; Hou, T. F.

    2017-12-01

    In this study,the friction and wear behavior of PVD coatings which were treated by 5 different processes,based on gear material-40Cr. Analyzing the effects of treating the gear material with electron beam in combination with magnetron sputtering on it,for dry friction and wear properties.The result showed that the electron beam pretreated substrate was useful to improve the tribological performance of coating material.Furthermore, the surface roughness of coating, the bonding force between substrate and coating as well as the load are the main factors affecting the tribological performance of this coating. Most importantly, the contribution of plowing effect on friction coefficient should be considered when the surface roughness is high.

  5. A study of tribological behaviors of the phenolic composite coating reinforced with carbon fibers

    International Nuclear Information System (INIS)

    Song Haojie; Zhang Zhaozhu; Luo Zhuangzhu

    2007-01-01

    The nitric acid treatment was used as a method to bind acidic oxygen functional groups on carbon fiber surfaces, thereafter these fibers (CFO) and unmodified carbon fibers (CF) were incorporated into the phenolic composite coating for wear investigations. Surface analyses of the carbon fibers before and after treatments were performed by FTIR, X-ray photoelectron spectrometer (XPS). Tribological behaviors of carbon fibers filled phenolic coatings were investigated using a ring on block wear tests under dry friction condition, and the worn surfaces and the transfer films formed on the surface of counterpart ring were, respectively, studied by SEM and optical microscope. The results show that the additions of carbon fibers were able to reduce the friction coefficient of the phenolic coating and enhance the wear life of it, especially, the wear life of the phenolic coating was the best when content of carbon fibers is at 10 wt.%. Moreover, we found that the friction and wear behaviors of the phenolic coating reinforced with 10 wt.% CFO were better than those of the coating reinforced with 10 wt.% CF. FTIR and XPS analyses indicated that the oxygen functional groups, such as -OH, O-C=O, C=O, and C-O, were attached on the carbon fiber surfaces after the oxidated treatment. In both cases, appropriate treatments could effectively improve the mechanical and tribological properties in the phenolic composite coating due to the enhanced fiber-matrix interfacial bonding

  6. Flexural behavior of reinforced concrete beam with polymer coated pumice

    Science.gov (United States)

    Nainggolan, Christin Remayanti; Wijatmiko, Indradi; Wibowo, Ari

    2017-09-01

    Sustainable development has become an important issue due to the increasing consideration of preserving the nature. Many alternative for coarse aggregate replacement have been investigated ranging from natural and fabricated aggregates. In this study, natural aggregate pumice was investigated since it offers lower density that give paramount benefit in reducing total building weight and hence reducing the earthquake excitation effect and optimizing the structural dimension. However, the characteristic of porous surfaces of pumice causes excessive water absorption during concrete mixing process. Therefore, to reduce the additional water, the pumice aggregates were coated with polymer. The tested specimens consisted of normal concrete beams (NCB), uncoated pumice aggregate concrete beam (UPA) and polymer coated pumice aggregate concrete beam (PCP). The objective of the research was to obtain the effect of coating on the pumice aggregate to the flexural behavior of concrete beams. The lateral load-displacement behavior, ductility and collapse mechanism were studied. The results showed that there were only marginal drop on the load-carrying capacity of the pumice aggregate beam compared to those of normal beam. Additionally, the ductility coefficient of specimens UPA and PCP decreased of 11,97% and 14,03% respectively compared to NCB, and the ultimate load capacity decreased less than 1%. Overall, the pumice aggregate showed good characteristic for replacing normal coarse aggregate.

  7. Stress transfer in microdroplet tensile test: PVC-coated and uncoated Kevlar-29 single fiber

    Science.gov (United States)

    Zhenkun, Lei; Quan, Wang; Yilan, Kang; Wei, Qiu; Xuemin, Pan

    2010-11-01

    The single fiber/microdroplet tensile test is applied for evaluating the interfacial mechanics between a fiber and a resin substrate. It is used to investigate the influence of a polymer coating on a Kevlar-29 fiber surface, specifically the stress transfer between the fiber and epoxy resin in a microdroplet. Unlike usual tests, this new test ensures a symmetrical axial stress on the embedded fiber and reduces the stress singularity that appears at the embedded fiber entry. Using a homemade loading device, symmetrical tensile tests are performed on a Kevlar-29 fiber with or without polyvinylchloride (PVC) coating, the surface of which is in contact with two epoxy resin microdroplets during curing. Raman spectra on the embedded fiber are recorded by micro-Raman Spectroscopy under different strain levels. Then they are transformed to the distributions of fiber axis stress based on the relationship between stress and Raman shift. The Raman results reveal that the fiber axial stresses increase with the applied loads, and the antisymmetric interfacial shear stresses, obtained by a straightforward balance of shear-to-axial forces argument, lead to the appearance of shear stress concentrations at a distance to the embedded fiber entry. The load is transferred from the outer fiber to the embedded fiber in the epoxy microdroplet. As is observed by scanning electronic microscopy (SEM), the existence of a flexible polymer coating on the fiber surface reduces the stress transfer efficiency.

  8. Evaluation of bond strength of isothermally aged plasma sprayed thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Jin; Lee, Dong Hoon; Koo, Jae Mean; Song, Sung Jin; Seok, Chang Sung [Sungkyunkwan University, Suwon (Korea, Republic of); Kim, Mun Young [Korea Plant Service and Engineering Co., Ltd., Seongnam (Korea, Republic of)

    2008-07-15

    In this study, disk type of thermal barrier coating system for gas turbine blade was isothermally aged in the furnace changing exposure time and temperature. For each aging condition, bond tests for three samples were conducted for evaluating degradation of adhesive or cohesive strength of thermal barrier coating system. For as-sprayed condition, the location of fracture in the bond test was in the middle of epoxy which have bond strength of 57 MPa. As specimens are degraded by thermal aging, bond strength gradually decreased and the location of failure was also changed from within top coat at the earlier stage of thermal aging to the interface between top coat and TGO at the later stage due to the delamination in the coating.

  9. Surface treated fly ash filled modified epoxy composites

    Directory of Open Access Journals (Sweden)

    Uma Dharmalingam

    2015-01-01

    Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

  10. A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

    International Nuclear Information System (INIS)

    Thakur, Lalit; Arora, Navneet

    2013-01-01

    WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.

  11. A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Lalit; Arora, Navneet [Indian Institute of Technology Roorkee, Roorkee (India)

    2013-05-15

    WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.

  12. On the Electrochemical Behavior of PVD Ti-Coated AISI 304 Stainless Steel in Borate Buffer Solution

    Science.gov (United States)

    Fattah-alhosseini, Arash; Elmkhah, Hassan; Attarzadeh, Farid Reza

    2017-04-01

    This work aims at studying the electrochemical behavior of annealed pure titanium (Ti) and nano-structured (NS) Ti coating in borate buffer solutions. Cathodic arc evaporation was successfully applied to deposit NS Ti coating. Samples were characterized by means of scanning electron microscope and x-ray diffraction. Potentiodynamic polarization tests, electrochemical impedance spectroscopy, and Mott-Schottky analysis were employed to discuss the electrochemical behavior of samples thoroughly. Electrochemical measurements showed that the deposited NS Ti coating offers a superior passivity in borate buffer solutions of pH 9.0 and 9.5. Mott-Schottky analysis revealed that all passive films are of n-type semiconducting nature in these alkaline solutions and the deposition process did not alter the semiconducting type of passive films formed on samples. Additionally, this analysis showed that the NS Ti coating possessed lower levels of donor densities. Finally, all electrochemical tests showed that passive behavior of the NS Ti samples was superior, mainly due to the formation of thicker and less defective passive films.

  13. Cure and mechanical behaviors of cycloaliphatic/DGEBA epoxy blend system using electron-beam technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.R.; Heo, G.Y.; Park, S.J. [Korea Research Institute of Chemical Technology, Taejeon (Korea)

    2002-05-01

    4-Vinyl-1- cyclohexene diepoxide (VCE)/ diglycidyl ether of bisphenol -A(DGEBA) epoxy blends with benzylquinoxalinium hexafluoroanti-monate were cured using an electron-beam technique. the effect of DGEBA content to VCE on cure behavior, thermal stabilities, and mechanical properties was investigated. The composition of VCE/DGEBA blend system varied within 100:0, 80:20, 60:40. 40:60 20:80, and 0:100wt%. The cure behavior and thermal stability of the cured specimens was monited by near-infrared spectroscopy and thermogravimetric analysis, respectively. Also, the critical stress intensity factor (K{sub 1C}) test of the cured specimens was performed to study the mechanical interfacial properties. As a result, the decreases of short side-chide structure and chain scission were observed in NIR measurements as the DGEBA content increases, resulting in varying the hydroxyl and carbonyl groups. And, the initial decomposition temperature (IDT), temperature of maximum weight loss (T{sub max}), and decomposition activation energy (E{sub d}) as thermal stability factors were increased with increasing the DGEBA content. These results could be explained by mean of decreasing viscosity, stable aromatic ring structure, and grafted interpenetrating polymer network with increasing of DGEBA content. Also, the maximum K{sub 1C} value showed at mixing ratio of 40:60 wt% in this blend system. (author). 22 refs., 2 tabs., 6 figs.

  14. Contact allergy to epoxy (meth)acrylates.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Jungewelter, Soile; Henriks-Eckerman, Maj-Len; Kuuliala, Outi; Jolanki, Riitta

    2009-07-01

    Contact allergy to epoxy (meth)acrylates, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA), 2,2-bis[4-(2-hydroxy-3-acryloxypropoxy)phenyl]-propane (bis-GA), 2,2-bis[4-(methacryl-oxyethoxy)phenyl] propane (bis-EMA), 2,2-bis[4-(methacryloxy)phenyl]-propane (bis-MA), and glycidyl methacrylate (GMA) is often manifested together with contact allergy to diglycidyl ether of bisphenol A (DGEBA) epoxy resin. To analyse patterns of concomitant allergic reactions to the five epoxy (meth)acrylates in relation to exposure. We reviewed the 1994-2008 patch test files at the Finnish Institute of Occupational Health (FIOH) for reactions to the five epoxy (meth)acrylates, and examined the patients' medical records for exposure. Twenty-four patients had an allergic reaction to at least one of the studied epoxy (meth)acrylates, but specific exposure was found only in five patients: two bis-GMA allergies from dental products, two bis-GA allergies from UV-curable printing inks, and one bis-GA allergy from an anaerobic glue. Only 25% of the patients were negative to DGEBA epoxy resin. The great majority of allergic patch test reactions to bis-GMA, bis-GA, GMA and bis-EMA were not associated with specific exposure, and cross-allergy to DGEBA epoxy resin remained a probable explanation. However, independent reactions to bis-GA indicated specific exposure. Anaerobic sealants may induce sensitization not only to aliphatic (meth)acrylates but also to aromatic bis-GA.

  15. Effect of elastic-plastic behavior of coating layer on drawability and frictional characteristic of galvannealed steel sheets

    International Nuclear Information System (INIS)

    Lee, Seong Won; Lee, Jung Min; Joun, Man Soo; Kim, Dong Hwan

    2016-01-01

    During a galvannealed sheet metal forming, the failures of coating layers (powdering, flaking and cracking) frequently affect the strain state of sheets and deteriorate the frictional characteristic between sheets and tools. Two FE-models in this study were suggested to investigate the effects of the mechanical behavior of coating layers on the formability and friction of the coated steel sheets in FE analysis; the first is one-layer model to express the coated sheet as one stress-strain curve and the second is a multiple-layer model which is composed of substrates and coating layers, separately. First, the frictional properties and the formability of the coated sheets were experimentally investigated using a cup deep-drawing trial. After, the drawing process was simulated by FE analysis of the two models. In the multiplelayer model, the mechanical behavior of the coating is defined as a stress-strain curve which was determined using the nanoindentation test of the coating, its FE analysis and artificial neural network method. The result showed that the multiple-layer model provides more accuracy predictions of drawing loads than the one-layer model in the FE analysis, compared to the actual cup drawing test.

  16. Effect of elastic-plastic behavior of coating layer on drawability and frictional characteristic of galvannealed steel sheets

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Won; Lee, Jung Min [Korea Institute of Industrial Technology, Jinju (Korea, Republic of); Joun, Man Soo [Gyeongsang National University, Jinju (Korea, Republic of); Kim, Dong Hwan [International University of Korea, Jinju (Korea, Republic of)

    2016-07-15

    During a galvannealed sheet metal forming, the failures of coating layers (powdering, flaking and cracking) frequently affect the strain state of sheets and deteriorate the frictional characteristic between sheets and tools. Two FE-models in this study were suggested to investigate the effects of the mechanical behavior of coating layers on the formability and friction of the coated steel sheets in FE analysis; the first is one-layer model to express the coated sheet as one stress-strain curve and the second is a multiple-layer model which is composed of substrates and coating layers, separately. First, the frictional properties and the formability of the coated sheets were experimentally investigated using a cup deep-drawing trial. After, the drawing process was simulated by FE analysis of the two models. In the multiplelayer model, the mechanical behavior of the coating is defined as a stress-strain curve which was determined using the nanoindentation test of the coating, its FE analysis and artificial neural network method. The result showed that the multiple-layer model provides more accuracy predictions of drawing loads than the one-layer model in the FE analysis, compared to the actual cup drawing test.

  17. Design of carbon nanofiber embedded conducting epoxy resin

    International Nuclear Information System (INIS)

    Gantayat, Subhra; Sarkar, Niladri; Rout, Dibyaranjan; Swain, Sarat K.

    2017-01-01

    Acid treated carbon nanofiber (t-CNF) reinforced epoxy nanocomposites were fabricated by hand lay-up method with various wt % of t-CNF loadings. Pristine or unmodified carbon nano fibers (u-CNFs) were made compatible with epoxy matrix by means of mixed acid treatment. Fabricated nanocomposites were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) study, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Mechanical and thermal properties of the nanocomposites were measured as a function of t-CNF content. Effect of acid treated CNFs on to the mechanical properties of epoxy nanocomposites was justified by comparing the mechanical properties of epoxy/t-CNF and epoxy/u-CNF nanocomposites with same loading level. The electrical conductivity was achieved by epoxy resin with a threshold at 1 wt % of t-CNF. Substantial improvement in thermal, mechanical and electrical properties of the synthesized epoxy/t-CNF nanocomposites may be suitable for fabricating electronic devices. - Highlights: • Epoxy/t-CNF nanocomposites are characterized by XRD, FTIR, SEM, AFM and TEM. • Electrical conductivity was achieved by epoxy with a threshold at 1 wt% of t-CNF. • Tensile strength is enhanced by 40% due to dispersion of t-CNF. • Synthesized nanocomposites are suitable for fabricating electronic devises.

  18. Design of carbon nanofiber embedded conducting epoxy resin

    Energy Technology Data Exchange (ETDEWEB)

    Gantayat, Subhra [Department of Chemistry, Veer Surendra Sai University of Technology, Burla, Sambalpur 768018, Odisha (India); School of Applied Sciences, KIIT University, Bhubaneswar 751024, Odisha (India); Sarkar, Niladri [Department of Chemistry, Veer Surendra Sai University of Technology, Burla, Sambalpur 768018, Odisha (India); Rout, Dibyaranjan [School of Applied Sciences, KIIT University, Bhubaneswar 751024, Odisha (India); Swain, Sarat K., E-mail: swainsk2@yahoo.co.in [Department of Chemistry, Veer Surendra Sai University of Technology, Burla, Sambalpur 768018, Odisha (India)

    2017-01-15

    Acid treated carbon nanofiber (t-CNF) reinforced epoxy nanocomposites were fabricated by hand lay-up method with various wt % of t-CNF loadings. Pristine or unmodified carbon nano fibers (u-CNFs) were made compatible with epoxy matrix by means of mixed acid treatment. Fabricated nanocomposites were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) study, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Mechanical and thermal properties of the nanocomposites were measured as a function of t-CNF content. Effect of acid treated CNFs on to the mechanical properties of epoxy nanocomposites was justified by comparing the mechanical properties of epoxy/t-CNF and epoxy/u-CNF nanocomposites with same loading level. The electrical conductivity was achieved by epoxy resin with a threshold at 1 wt % of t-CNF. Substantial improvement in thermal, mechanical and electrical properties of the synthesized epoxy/t-CNF nanocomposites may be suitable for fabricating electronic devices. - Highlights: • Epoxy/t-CNF nanocomposites are characterized by XRD, FTIR, SEM, AFM and TEM. • Electrical conductivity was achieved by epoxy with a threshold at 1 wt% of t-CNF. • Tensile strength is enhanced by 40% due to dispersion of t-CNF. • Synthesized nanocomposites are suitable for fabricating electronic devises.

  19. Thermo-curable epoxy systems for nanoimprint lithography

    International Nuclear Information System (INIS)

    Wu, Chun-Chang; Hsu, Steve Lien-Chung

    2010-01-01

    In this work, we have used solvent-free thermo-curable epoxy systems for low-pressure and moderate-temperature nanoimprint lithography (NIL). The curing kinetic parameters and conversion of diglycidyl ether of bisphenol A (DGEBA) resin with different ambient-cure 930 and 954 hardeners were studied by the isothermal DSC technique. They are useful for the study of epoxy resins in the imprinting application. The DGEBA/930 and DGEBA/954 epoxy resists can be imprinted to obtain high-density nano- and micro-scale patterns on a flexible indium tin oxide/poly(ethylene terephthalate) (ITO/PET) substrate. The DGEBA/930 epoxy resin is not only suitable for resist material, but also for plastic mold material. Highly dense nanometer patterns can be successfully imprinted using a UV-curable resist from the DGEBA/930 epoxy mold. Using the replicated DGEBA/930 epoxy mold instead of the expensive master can prevent brittle failure of the silicon molds in the NIL

  20. Hydrogen transport behavior of metal coatings for plasma-facing components

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R. (Idaho National Engineering Lab., Idaho Falls (USA))

    1990-12-01

    Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3 keV D{sub 3}{sup +} ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates of tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 to 825 K and implanting particle fluxes of approximately 5x10{sup 19} D/m{sup 2} s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs. (orig.).

  1. Hydrogen transport behavior of metal coatings for plasma-facing components

    Science.gov (United States)

    Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

    1990-12-01

    Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3 keV D +3 ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates for tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 to 825 K and implanting particle fluxes of approximately 5 × 10 19 D/m 2 s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs.

  2. Hydrogen transport behavior of metal coatings for plasma facing components

    International Nuclear Information System (INIS)

    Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

    1990-01-01

    Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3-keV D 3 + ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates for tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 K to 825 K and implanting particle fluxes of approximately 5 x 10 19 D/m 2 s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs. 18 refs., 3 figs., 3 tabs

  3. Fatigue life extension of epoxy materials using ultrafast epoxy-SbF5 healing system introduced by manual infiltration

    Directory of Open Access Journals (Sweden)

    X. J. Ye

    2015-03-01

    Full Text Available The present paper is devoted to the verification of the capability of epoxy-SbF5 system as a healing chemistry for rapidly retarding and/or arresting fatigue cracks in epoxy materials at room temperature. Owing to the very fast curing speed of epoxy catalyzed by SbF5, epoxy monomer and the hardener (ethanol solution of SbF5–ethanol complex are successively infiltrated into the fracture plane under cyclic loading during the tension-tension fatigue test. As a result, the mechanisms including hydrodynamic pressure crack tip shielding, polymeric wedge and adhesive bonding of the healing agent are revealed. It is found that the healing agent forms solidified wedge at the crack tip within 20 s after start of polymerization of the epoxy monomer, so that the highest healing effect is offered at the moment. The epoxy-SbF5 system proves to be effective in rapidly obstructing fatigue crack propagation (despite that its cured version has lower fracture toughness than the matrix, and satisfies the requirement of constructing fast self-healing polymeric materials.

  4. Mechanical Properties Analysis Of Composite Magnetic Base On hexa ferrite And Polyester Or Epoxy Matrix With Silane Additive Addition

    International Nuclear Information System (INIS)

    Sudirman; Ridwan; Mujamilah; K K, Aloma; Rembulan, Marisa; Fitriyanti

    2003-01-01

    Application of composite magnetic especially hexa ferrite magnet for industry and home industry in Indonesia has been used. Research purposes were making composite magnetic by mixing hexa ferrite powder with polyester or epoxy and studying the effect of coupling agent 3-aminopropyltriethoxysilane (3-APE) addition on mechanical properties of composite magnetic. The coupling agent may increase bonding properties between magnetic powder and matrix polymer, so that tensile strength of magnetic composite will increase without decreasing the magnetic properties. Magnetic powder (SrM or BaM) wich be coated by coupling agent were added to matrix polyester and mekpo or epoxy and versamid, mixed until homogen then pressing into to the dumbbell form molding. For epoxy matrix, pressing was done in hot press at 70 deg. C and 150 kg/cm 2 following by cooling in cold press, while for polyester matrix pressing was done in hydraulic press and following by curing at 70 deg. C in an oven for 1 hour. The composition of magnetic powder were varied to 30, 40 and 50% volume fraction and coupling agent were varied to 5, 10 and 15 ml for every volume fraction. The result showed that 10 ml added of coupling agent was give best mechanical properties both polyester and epoxy matrix. However generally, increasing of magnetic powder content decreased the tensile strength of magnetic composite. The properties of magnetic composite SrM was better than BaM either in polyester or epoxy matrix

  5. Mechanical properties and environmental effects of epoxy resins in the neat state and in composites

    International Nuclear Information System (INIS)

    Yang, C.M.P.

    1984-01-01

    The dynamic mechanical properties of graphite fiber reinforced, epoxy matrix composite laminates subjected to loading perpendicular to the plane of lamination and of neat epoxy resin are reported. The centrosymmetric deformation (CSD) test geometry provides an accurate and convenient test mode for the study of the viscoelastic behavior of very stiff graphite-epoxy laminates. It is found that the in-phase and out-of-phase stiffness superpose to form master curves covering a frequency range of 12 decades. By a suitable scaling procedure of the master curves, it is found that the in-phase stiffness has the same shape and the out-of-phase has the same dispersion for all laminates irrespective of the stacking sequence. The dispersion characteristics of in-situ and neat resin epoxy were nearly identical, but with the neat resin having a lower glass-transition temperature. The graphite/epoxy composites and neat resin epoxy have been shown to be sensitive to hygrothermal environment. For postcured specimens the plasticization and inhomogeneous swelling effects due to the moisture absorbed are found to be reversible, in the sense that the initially dry properties of the laminate are recovered after redrying the wet specimen. On the other hand, for as cured specimens, the plasticization and inhomogeneous swelling effects are found to be irreversible under the same hygrothermal environment

  6. Coating for the fixation of superficial contamination of materials

    International Nuclear Information System (INIS)

    Brambilla, G.; Monari, D.; Pellicano, G.

    1984-01-01

    Low cost, commercially available and easy to apply coatings are examined to prevent metal corrosion and to limit cement dust formation during power reactor dismantling. Epoxy compounds are selected because of anticorrosive properties, ease of application on any support, even without preparation and they are efficient for 1 to 5 years. Containment and radiation resistance up to 600 Mrads are studied on samples coated with one or two layers. For application the airless system is the more appropriate. An equipment is concerned and for highly radioactive environment automation and remote operation with a modified commercial robot is studied

  7. Engineering model for intumescent coating behavior in a pilot-scale gas-fired furnace

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2016-01-01

    placed behind the substrate. A mathematical model, describing the intumescent coating behavior and temperatures in the furnace using a single overall reaction was developed and validated against experimental data. By including a decomposition front movement through the char, a good qualitative agreement...... was obtained. After further validation against experiments with other coating formulations, it has potential to become a practical engineering tool. This article is protected by copyright. All rights reserved....

  8. Characterization of the corrosion behavior of an austenitic stainless steel for biomedical applications coated with Ti N, Ti CN And DLC PVD coatings

    International Nuclear Information System (INIS)

    Antunes, Renato Altobelli

    2006-01-01

    Metallic biomaterials must present a combination of properties such as corrosion resistance, biocompatibility and mechanical resistance. Austenitic stainless steels, especially AISI 316L combine these properties with the easy of fabrication at low cost. However, they are prone to corrosion in physiological solutions. Furthermore, their corrosion products may lead to infectious ou allergenic reactions in the tissues around the implant device. In the present work, coatings produced by physical vapour deposition (PVD) methods have been applied on the surface of a 316L stainless steel to increase its corrosion resistance and biocompatibility. Three thin films were tested: titanium nitride (TiN), titanium carbonitride (TiCN) and diamond-like carbon (DLC). These materials present high hardness, wear resistance and intrinsic biocompatibility that are key features when considering biomedical applications. The characterization of the electrochemical behavior of the stainless steel coated with the three different films showed that the presence of surface defects are deleterious to the corrosion resistance of the substrate. These defects were observed using scanning electron microscopy. The evolution of the electrochemical behavior of the coated steel was explained through a mechanism based on the experimental results obtained using electrochemical impedance spectroscopy. Two different passivation treatments were carried out on the stainless steel surface, either in sulfuric or nitric acid solutions, to increase its corrosion resistance. The results suggested que these treatments were not efficient, but may be modified to improve its performance. The electronic properties of the passive films of the non-passivated and passivated stainless steel were studied using the Mott-Schottky approach. The films presented a duplex character. Below the flat band potential the behavior is typical of a highly doped type-p semiconductor. Above the flat band potential is typical of a highly

  9. Design and Analysis of Drive Shaft using Kevlar/Epoxy and Glass/Epoxy as a Composite Material

    Science.gov (United States)

    Karthikeyan, P.; Gobinath, R.; Kumar, L. Ajith; Jenish, D. Xavier

    2017-05-01

    In automobile industry drive shaft is one of the most important components to transmit power form the engine to rear wheel through the differential gear. Generally steel drive shaft is used in automobile industry, nowadays they are more interested to replace steel drive shaft with that of composite drive shaft. The overall objective of this paper is to analyze the composite drive shaft using to find out the best replacement for conventional steel drive shaft. The uses of advanced composite materials such as Kevlar, Graphite, Carbon and Glass with proper resins ware resulted in remarkable achievements in automobile industry because of its greater specific strength and specific modulus, improved fatigue and corrosion resistances and reduction in energy requirements due to reduction in weight as compared to steel shaft. This paper is to presents, the modeling and analysis of drive shaft using Kevlar/Epoxy and Glass/Epoxy as a composite material and to find best replacement for conventional steel drive shafts with an Kevlar/epoxy or Glass/Epoxy resin composite drive shaft. Modeling is done using CATIA software and Analysis is carried out by using ANSYS 10.0 software for easy understanding. The composite drive shaft reduces the weight by 81.67 % for Kevlar/Epoxy and 72.66% for Glass/Epoxy when compared with conventional steel drive shaft.

  10. Comparison of structural health assessment capabilities in epoxy – carbon black and epoxy – carbon nanotube nanocomposites

    Directory of Open Access Journals (Sweden)

    F. Inam

    2014-01-01

    Full Text Available A novel method for comparing structural health of different types of brittle epoxy nanocomposites filled with carbon nanostructured fillers is presented. Epoxy – 0.2 vol% carbon black (CB and epoxy – 0.2 vol% carbon nanotube (CNT nanocomposite bars were prepared by calendering and thermal curing. Nanocomposite bars were subjected to Vickers diamond indentation to produce sub-surface damage. Electrical conductivities were analysed by 4-point method to estimate the structural damage caused by indentation. For comprehensive comparison, fracture toughness and percolation threshold were analysed as well. Because of the systematically induced indentation damage, a sharp decrease of 89% was observed in the electrical conductivity of epoxy – CNT nanocomposite as compared to 25% in the electrical conductivity of epoxy – CB nanocomposite. CNTs impart superior damage sensing capability in brittle nanocomposite structures, in comparison to CB, due to their high aspect ratio (fibrous nature and high electrical conductivity.

  11. ADHESION OF BIOCOMPATIBLE TiNb COATING

    Directory of Open Access Journals (Sweden)

    Tomas Kolegar

    2017-06-01

    Full Text Available Preparation of a coating with a high quality requires good adhesion of the film to the substrate. The paper deals with the adhesion of biocompatible TiNb coating with different base materials. Several materials such as titanium CP grade 2, titanium alloys Ti6Al4V and stainless steel AISI 316L were measured. Testing samples were made in the shape of small discs. Those samples were coated with a TiNb layer by using the PVD method (magnetron sputtering. Onto the measured layer of TiNb an assistant cylinder was stuck using a high strength epoxy adhesive E1100S. The sample with the assistant cylinder was fixed into a special fixture and the whole assembly underwent pull-off testing for adhesion. The main result of this experiment was determining the strength needed to peel the layer and morphology and size of the breakaway. As a result, we will be able to determine the best base material and conditions where the coating will be remain intact with the base material.

  12. Inhibition of microbial concrete corrosion by Acidithiobacillus thiooxidans with functionalised zeolite-A coating.

    Science.gov (United States)

    Haile, Tesfaalem; Nakhla, George

    2009-01-01

    The inhibition of the corrosive action of Acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-A containing 14% zinc and 5% silver by weight was studied. Uncoated concrete specimens, epoxy-coated concrete specimens (EP), and functionalised zeolite-A coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (Z1), 2:2 (Z2) and 1:3 (Z3) were studied. Specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy for the identification of corrosion products and morphological changes. Biomass growth at the conclusion of the 32-day experiments was 4, 179 and 193 mg volatile suspended solids g(-1) sulphur for the uncoated, EP and Z1 specimens, whereas that of Z2 and Z3 were negligible. In the uncoated, EP and Z1 specimens, sulphate production rates were 0.83, 9.1 and 8.8 mM SO(4)(2-) day(-1) and the specific growth rates, mu, were 0.14, 0.57 and 0.47 day(-1), respectively. The corresponding values for Z2 and Z3 were negligible due to their bacterial inhibition characteristics.

  13. Fatigue of graphite/epoxy buffer strip panels with center cracks

    Science.gov (United States)

    Bigelow, C. A.

    1985-01-01

    The effects of fatigue loading on the behavior of graphite/epoxy panels with either S-Glass or Kevlar-49 buffer strips is studied. Buffer strip panels are fatigued and tested in tension to measure their residual strength with crack-like damage. Panels are made with 45/0/-45/90 sub 2s layup with either S-Glass or Kevlar-49 buffer strip material. The buffer strips are parallel to the loading direction and made by replacing narrow strips of the 0-degree graphite plies with strips of either 0-degree S-Glass/epoxy or Kevlar-49/epoxy on a one-for-one basis. The panels are subjected to a fatigue loading spectrum MINITWIST, the shortened version of the standardized load program for the wing lower surface of a transport aircraft. Two levels of maximum strain are used in the spectrum with three durations of the fatigue spectrum. One group of panels is preloaded prior to the application of the fatigue cycling. The preload consists of statistically loading the spectrum in tension until the crack-tip damage zone reaches the ajacent buffer strips. After fatigue loading, all specimens are statistically loaded in tension to failure to determine their residual strengths.

  14. In-situ phosphatizing coatings for aerospace, OEM and coil coating applications

    Science.gov (United States)

    Neuder, Heather Aurelia

    The current metal coating process is a multi-step process. The surface is cleaned, primered, dried and then painted. The process is labor intensive and time consuming. The wash primer is a conversion coating, which prepares metal surface for better paint adhesion. The wash primers currently used often contain hexavalent chromium (Cr6+), which seals the pores in the conversion coating. The presence of hexavalent chromium, a known carcinogen, and volatile organic compounds (VOCs) make waste disposal expensive and pose dangers to workers. The novel technique of in-situ phosphatizing coating (ISPC) is a single-step, chrome-free alternative to the present coating practice. Formulation of an ISPC involves predispersal of an in-situ phosphatizing reagent (ISPR) into the paint system to form a stable formulation. The ISPR reacts with the metal surface and bonds with the paint film simultaneously, which eliminates the need for a conversion coating. In acid catalyzed paint systems, such as polyester-melamine paints, the ISPR also catalyzes cross-linking reactions between the melamine and the polyester polyols. ISPCs are formulated using commercially available coating systems including: polyester-melamine, two-component epoxy, polyurethane and high-hydroxy content polyester-melamine coil coating. The ISPCs are applied to metal substrates and their performances are evaluated using electrochemical, thermal and standard American Society for Testing and Materials (ASTM) testing methods. In addition, ISPCs were designed and formulated based on: (1) phosphate chemistry, (2) polymer chemistry, (3) sol-gel chemistry, and (4) the ion-exchange principle. Organo-functionalized silanes, which serve as excellent coupling and dispersion agents, are incorporated into the optimized ISPC formula and evaluated using standard ASTM testing methods and electrochemical spectroscopy. Also, an ion-exchange pigment, which leads to better adhesion by forming a mixed metal silicate surface, is

  15. Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Raman P. Singh

    2010-01-01

    Full Text Available This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

  16. Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

    International Nuclear Information System (INIS)

    Singh, R.P.; Zunjarrao, S.C.; Pandey, G.; Khait, M.; Korach, C.S.

    2010-01-01

    This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

  17. Electrochemical behavior and microstructural characterization of 1026 Ni-B coated steel

    International Nuclear Information System (INIS)

    Contreras, A.; Leon, C.; Jimenez, O.; Sosa, E.; Perez, R.

    2006-01-01

    Ni-B coatings have been deposited on the surfaces of commercial steels (SAE-1026). The depositions were carried out using the electroless plating technique employing a nickel chloride solution with borane-dimethylamine as the reducing agent. These specimens were subsequently heat treated at different temperatures (300-500 deg. C) and different periods of time. The obtained coating thickness was in the order of approximately 1.5 μm. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to characterize the structure and superficial morphology of the coatings. Phases like Ni, Ni 3 B and Ni 4 B 3 were observed through X-ray diffraction and confirmed by differential scanning calorimeter (DSC) studies. Some of the precipitated phases have been structurally characterized. The corrosion behavior of the coated surfaces was carried out by electrochemical impedance spectroscopy (EIS) using electrolytic sodium chlorine solutions with pH 2 and 7. The EIS results showed an active corrosion mechanism in acid solution while diffusion-reaction phenomena are predominant in neutral solution

  18. Occupational exposure to epoxy resins

    NARCIS (Netherlands)

    Terwoert, J.; Kersting, K.

    2014-01-01

    Products based on epoxy resins as a binder have become popular in various settings, among which the construction industry and in windmill blade production, as a result of their excellent technical properties. However, due to the same properties epoxy products are a notorious cause of allergic skin

  19. Fretting and wear behaviors of Ni/nano-WC composite coatings in dry and wet conditions

    International Nuclear Information System (INIS)

    Benea, Lidia; Başa, Sorin-Bogdan; Dănăilă, Eliza; Caron, Nadège; Raquet, Olivier; Ponthiaux, Pierre; Celis, Jean-Pierre

    2015-01-01

    Highlights: • The friction and wear properties of Ni/nano-WC composite were studied. • Nano-WC reinforcement decreased friction coefficient in dry and wet conditions. • Nano-WC reinforcement fraction was seen to be 12 wt.%. • Nanohardness increased by 27% compared to nickel without WC reinforcements. • Ennoblement of OCP corresponding to the Ni/nano-WC composite coating. - Abstract: The fretting and wear behaviors of Ni/nano-WC composite coatings were studied by considering the effect of fretting frequency of 1 Hz during 10,000 cycles, at different applied loads in dry or wet conditions. The studies were performed on a ball-on-disk tribometer and the results were compared with pure Ni coating. The nanohardness of pure Ni and Ni/nano-WC composite coatings was tested by nanoindentation technique. To evaluate the wet wear (tribocorrosion) behavior the open circuit potential (OCP) was measured before, during and after the fretting tests at room temperature in the solution that simulates the primary water circuit of Pressurized Water Reactors (PWRs). The results show that Ni/nano-WC composite coatings exhibited a low friction coefficient, high nanohardness and wear resistance compared with pure Ni coatings under similar experimental conditions. Ni/nano-WC composite coatings were obtained on stainless steel support by electrochemical codeposition of nano-sized WC particles (diameter size of ∼60 nm) with nickel, from a standard nickel Watts plating bath. The surface morphology and the composition of the coatings were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) respectively

  20. Analyzing FTIR spectra using high sensitivity compare function of FTIR software for 2-pack epoxy paints

    Science.gov (United States)

    Saaid, Farish Irfal; Chan, Chin Han; Ong, Max Chong Hup; Winie, Tan; Harun, Mohamad Kamal

    2015-08-01

    The existing problem of oil and gas companies faced for on-site jobs of polymeric coatings on steel pipelines is that the quality of polymeric coatings varies from job to job for the same product brand from the same supplier or paint manufacturer. This can be due to the inherent problem of the reformulation of polymeric coatings or in other words adulterated polymeric coatings are supplied, where the quality of the coatings deviates from the submitted specifications for prequalification and tender purpose. Major oil and gas companies in Malaysia are calling for Coating Fingerprinting Certificate for the supply of polymeric coatings from local paint manufactures as quality assurance requirement of the coatings supplied. This will reduce the possibility of failures of the polymeric coatings, which lead to the corrosion of steel pipelines resulting in leakage of crude oil and gas to the environment. In this case, Fourier-transform infrared (FTIR) is a simple and reliable tool for coating fingerprinting. In this study, we conclude that, revelation of possible components of the 2-pack epoxy paints by carrying out extensive FTIR libraries search on FTIR spectra seems to be extremely challenging. Estimation of correlation of the sample spectrum to that of the reference spectrum using Compare function from one FTIR manufacturer, even the FTIR spectra are collected by different FTIR spectrometers from different FTIR manufacturers, can be made. The results of the correlation are reproducible.