The Structure of the Silumin Coat on Alloy Cast Steels

Directory of Open Access Journals (Sweden)

T. Szymczak

2012-04-01

Full Text Available The work presents the analysis results of the structure of the coat obtained by dipping in silumin AlSi5 of two grades of alloy cast steel: GX6CrNiTi18-10 (LH18N9T and GX39Cr13 (LH14. The temperature of the silumin bath was 750±5°C, and the hold-up time of the cast steel element τ = 180 s. The absolute thickness of the coat obtained in the given conditions was g = 104 μm on cast steel GX6CrNiTi18-10 and g = 132 μm on GX39Cr13. The obtained coat consisted of three layers of different phase structure. The first layer from the base “g1`” was constructed of the phase AlFe including Si and alloy additives of the tested cast steel grades: Cr and Ni (GX6CrNiTi18-10 and Cr (GX39Cr13. The second layer “g1``” of intermetallic phases AlFe which also contains Si and Cr crystallizes on it. The last, external layer “g2” of the coat consists of the silumin containing the intermetallic phases AlFeSi which additionally can contain alloy additives of the cast steel. It was shown that there were no carbides on the coat of the tested cast steels which are the component of their microstructure, as it took place in the case of the coat on the high speed steels.

Influence of the cooling method on the structure of 55AlZn coatings

Energy Technology Data Exchange (ETDEWEB)

Mendala, J, E-mail: jacek.mendala@polsl.pl [Department of Materials Technology, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

2011-05-15

In metallization processes, metals or metal alloys are used which have a low melting point and good anticorrosion properties. Moreover, they must form durable intermetallic compounds with iron or its alloys. The most common hot-dip metallization technology involves galvanizing, however, molten multi-component metal alloys are used as well. An addition of aluminium to the zinc bath causes an increase in corrosion resistance of the obtained coatings. The article presents results of tests of obtaining coatings by the batch hot-dip method in an 55AlZn bath. Kinetics of the coating growth in the tested alloys were determined in the changeable conditions of bath temperature, dip time and type of cooling. The structure of coatings and their phase composition were revealed. As a result of the tests performed, it has been found that an increase in total thickness of the coatings as a function of the dipping time at a constant temperature is almost of a parabolic nature, whereas an increase in the transient layer is of a linear nature. The structure was identified by the XRD analysis and the morphology of the coatings was tested by means of SEM. It has been found that the cooling process with the use of higher rates of cooling causes a size reduction of the structure in the outer layer and a reduction of thickness of both the intermediate diffusion layer and the whole coating by ca. 25 %.

D. C. plasma-sprayed coatings of nano-structured alumina-titania-silica

International Nuclear Information System (INIS)

Jiang Xianliang

2002-01-01

nano-crystalline powders of ω(Al 2 O 3 ) = 95%, ω(TiO 2 ) = 3%, and ω(SiO 2 ) = 2%, were reprocessed into agglomerated particles for plasma spraying, by using consecutive steps of ball milling, slurry forming, spray drying, and heat treatment. D.C. plasma was used to spray the agglomerated nano-crystalline powders, and resultant coatings were deposited on the substrate of stainless steel. Scanning electron microscopy (SEM) was used to examine the morphology of the agglomerated powders and the cross section of the alumina-titania-silica coatings. Experimental results show that the agglomerated nano-crystalline particles are spherical, with a size from (10-90) μm. The flow ability of the nano-crystalline powders is greatly improved after the reprocessing. The coatings deposited by the plasma spraying are mainly of nano-structure. Unlike conventional plasma-sprayed coatings, no laminar layer could be found in the nano-structured coatings. Although the nano-structured coatings have a lower microhardness than conventional microstructured coatings, the toughness of the nano-structured ceramic coatings is significantly improved

Accelerated life assessment of coating on the radar structure components in coastal environment.

Science.gov (United States)

Liu, Zhe; Ming, ZhiMao

2016-07-04

This paper aimed to build an accelerated life test scheme and carry out quantitative analysis between accelerated life test in the laboratory and actual service for the coating composed of epoxy primer and polyurethane paint on structure components of some kind of radar served in the coastal environment of South China Sea. The accelerated life test scheme was built based on the service environment and failure analysis of the coating. The quantitative analysis between accelerated life test and actual service was conducted by comparing the gloss loss, discoloration, chalking, blistering, cracking and electrochemical impedance spectroscopy of the coating. The main factors leading to the coating failure were ultraviolet radiation, temperature, moisture, salt fog and loads, the accelerated life test included ultraviolet radiation, damp heat, thermal shock, fatigue and salt spray. The quantitative relationship was that one cycle of the accelerated life test was equal to actual service for one year. It was established that one cycle of the accelerated life test was equal to actual service for one year. It provided a precise way to predict actual service life of newly developed coatings for the manufacturer.

Ag-Ti(C, N)-based coatings for biomedical applications: influence of silver content on the structural properties

International Nuclear Information System (INIS)

Manninen, N K; Carvalho, S; Galindo, R Escobar; Benito, N; Palacio, C; Figueiredo, N M; Cavaleiro, A

2011-01-01

Ag-TiCN coatings were deposited by dc reactive magnetron sputtering and their structural and morphological properties were evaluated. Compositional analysis showed the existence of Ag-TiCN coatings with different Ag/Ti atomic ratios (ranging from 0 to 1.49). The structural and morphological properties are well correlated with the evolution of Ag/Ti atomic ratio. For the samples with low Ag/Ti atomic ratio (below 0.20) the coatings crystallize in a B1-NaCl crystal structure typical of TiC 0.3 N 0.7 . The increase in Ag/Ti atomic ratio promoted the formation of Ag crystalline phases as well as amorphous CN x phases detected in both x-ray photoelectron spectroscopy and Raman spectroscopy analysis. Simultaneously to the formation of Ag crystalline phases and amorphous carbon-based phases, a decrease in TiC 0.3 N 0.7 grain size was observed as well as the densification of coatings.

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.

The structure and properties of single-layer and gradient-layered coatings of the Ti–Al–Si–Cr–Mo–S–N system

Energy Technology Data Exchange (ETDEWEB)

Ovchinnikov, Stanislav, E-mail: ovm@spti.tsu.ru; Pinzhin, Yurii, E-mail: pinzhin@phys.tsu.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

2015-10-27

Using the method of microprobe analysis and transmission electron microscopy, the influence of obtaining conditions upon particular elemental composition and growth structure coatings of Ti–Al–Si–Mo–S–N system was studied. The possibility of formation and characteristics of the structural and elastic-stress state single-layer coatings with nanoscale columnar or equiaxed grains and gradient-layered, combining two types of selected structure, was defined. On the basis of hardness, tribological properties and coating hardness, a conclusion was made about the relative prospects of its use as wear-resistant coatings with a nanocrystalline structure.

Topology optimization of coated structures and material interface problems

DEFF Research Database (Denmark)

Clausen, Anders; Aage, Niels; Sigmund, Ole

2015-01-01

This paper presents a novel method for including coated structures and prescribed material interface properties into the minimum compliance topology optimization problem. Several elements of the method are applicable to a broader range of interface problems. The approach extends the standard SIMP......-step filtering/projection approach. The modeled coating thickness is derived analytically, and the coating is shown to be accurately controlled and applied in a highly uniform manner over the structure. An alternative interpretation of the model is to perform single-material design for additive manufacturing...

Mechanical Properties and Structures of Pyrolytic Carbon Coating Layer in HTR Coated Particle Fuel

International Nuclear Information System (INIS)

Lee, Young Woo; Kim, Young Min; Kim, Woong Ki; Cho, Moon Sung

2009-01-01

The TRISO(tri-isotropic)-coated fuel particle for a HTR(High Temperature gas-cooled Reactor) has a diameter of about 1 mm, composed of a nuclear fuel kernel and four different outer coating layers, consisting of a buffer PyC (pyrolytic carbon) layer, inner PyC layer, SiC layer, and outer PyC layer with different coating thicknesses following a specific fuel design. While the fuel kernel is a source for a heat generation by a nuclear fission of fissile uranium, each of the four coating layers acts as a different role in view of retaining the generated fission products and the other interactions during an in-reactor service. Among these coating layers, PyC properties are scarcely in agreement among various investigators and the dependency of their changes upon the deposition condition is comparatively large due to their additional anisotropic properties. Although a recent review work has contributed to an establishment of relationship between the material properties and QC measurements, the data on the mechanical properties and structural parameters of PyC coating layers remain still unclearly evaluated. A review work on dimensional changes of PyC by neutron irradiation was one of re-evaluative works recently attempted by the authors. In this work, an attempt was made to analyze and re-evaluate the existing data of the experimental results of the mechanical properties, i.e., Young's modulus and fracture stress, in relation with the coating conditions, density and the BAF (Bacon Anisotropy Factor), an important structural parameter, of PyC coating layers obtained from various experiments performed in the early periods of the HTR coated particle development

Laminated structure in internally oxidized Ru-Ta coatings

Energy Technology Data Exchange (ETDEWEB)

Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw

2012-12-01

During the development of refractory alloy coatings for protective purposes at high temperature under oxygen-containing atmospheres, previous studies noted and examined the internal oxidation phenomenon for Mo-Ru and Ru-Ta coatings. The internally oxidized zone shows a laminated structure, consisting of alternating oxygen-rich and deficient layers stacked with a general orientation. Previous studies proposed a forming mechanism. To investigate in detail, Ru-Ta coatings were prepared with various rotating speeds of a substrate-holder. The coatings were annealed at 600 Degree-Sign C in an atmosphere continuously purged with 1% O{sub 2}-99% Ar mixed gas for 30 min. Transmission electron microscopy was used to examine the laminated-layer periods. Auger electron spectroscopy depth profiles certified the periodical variation of the related constituents. X-ray photoelectron spectroscopy proved the valence variation of Ta in the near surface, accompanied by the introduction of oxygen ions. The inward diffusion of oxygen was dominated by lattice diffusion. - Highlights: Black-Right-Pointing-Pointer Laminated Ru-Ta coatings consisted of a cyclical gradient concentration. Black-Right-Pointing-Pointer The as-deposited coatings showed a laminated structure with a period of 4-34 nm. Black-Right-Pointing-Pointer Internal oxidation of Ru-Ta coatings executed after annealing in 1% O{sub 2}-Ar atmosphere. Black-Right-Pointing-Pointer Oxygen inward diffusion was dominated by lattice diffusion.

Growth Structure and Properties of Gradient Nanocrystalline Coatings of the Ti-Al-Si-Cu-N System

Science.gov (United States)

Ovchinnikov, S. V.; Pinzhin, Yu. P.

2016-10-01

Methods of electron microprobe analysis, X-ray structure analysis and electron microscopy were used to study the element composition and features of the structure-phase, elastic stress state of nanocrystalline coatings of the Ti- Al- Si- Cu- N system with gradient of copper concentration across their thickness. The authors established the effects of element composition modification, non-monotonous behavior of the lattice constant of alloyed nitride and rise in the bending-torsion value of the crystalline lattice in individual nanocrystals to values of around 400 degrees/μm with increase in copper concentration, whereas the sizes of alloyed nitride crystals remained practically unchanged. Mechanical (hardness), adhesion and tribological properties of coatings were examined. Comparative analysis demonstrates higher values of adhesion characteristics in the case of gradient coatings of the Ti- Al- Si- Cu- N system than in the case of single-layer (with constant element concentration) analogues.

The Influence of Coating Structure on Micromachine Stiction

Energy Technology Data Exchange (ETDEWEB)

Kushmerick, J.G.; Hankins, M.G.; De Boer, M.P.; Clews, P.J.; Carpick, R.W.; Bunker, B.C.

2000-10-03

We have clearly shown that the film morphology dictates the anti-stiction properties of FDTS coatings. Release stiction is not observed when ideal monolayer films are present but can be extensive when thicker aggregate structures are present. This finding is significant because it indicates that agglomerate formation during processing is a major source of irreproducible behavior when FDTS coatings are used to release micromachined parts. The results could also help explain why coatings that are aged at high. humidity start to stick to each other. (AFM results show that humid environments promote the formation of aggregates from monolayer films.) The reason why aggregate structures promote stiction is currently unknown. However, it appears that aggregates interfere with the ability of FDTS to form dense, well-ordered coatings under microstructures, leading to surfaces that are sufficiently hydrophilic to allow for release stiction via an attractive Laplace force during drying.

Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

Energy Technology Data Exchange (ETDEWEB)

Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C., E-mail: weber@ikv-aachen.de [Institute of Plastics Processing (IKV) at RWTH Aachen University (Germany); Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T. [Surface Engineering Institute (IOT), RWTH Aachen University, Aachen (Germany); Steger, M. [Fraunhofer Institute for Laser Technology (ILT), Aachen (Germany)

2015-05-22

Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

Mechanical analysis of surface-coated zircaloy cladding

Energy Technology Data Exchange (ETDEWEB)

Lee, You Ho; Lee, Jeong Ik; No, Hee Cheon [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2017-08-15

A structural model for stress distributions of coated Zircaloy subjected to realistic incore pressure difference, thermal expansion, irradiation-induced axial growth, and creep has been developed in this study. In normal operation, the structural integrity of coating layers is anticipated to be significantly challenged with increasing burnup. Strain mismatch between the zircaloy and the coated layer, due to their different irradiation-induced axial growth, and creep deformation are found to be the most dominant causes of stress. This study suggests that the compatibility of the high temperature irradiation-induced strains (axial growth and creep) between zircaloy and the coating layer and the capability to undergo plastic strain should be taken as key metrics, along with the traditional focus on chemical protectiveness.

Prediction of protein-protein interactions in dengue virus coat proteins guided by low resolution cryoEM structures

Directory of Open Access Journals (Sweden)

Srinivasan Narayanaswamy

2010-06-01

Full Text Available Abstract Background Dengue virus along with the other members of the flaviviridae family has reemerged as deadly human pathogens. Understanding the mechanistic details of these infections can be highly rewarding in developing effective antivirals. During maturation of the virus inside the host cell, the coat proteins E and M undergo conformational changes, altering the morphology of the viral coat. However, due to low resolution nature of the available 3-D structures of viral assemblies, the atomic details of these changes are still elusive. Results In the present analysis, starting from Cα positions of low resolution cryo electron microscopic structures the residue level details of protein-protein interaction interfaces of dengue virus coat proteins have been predicted. By comparing the preexisting structures of virus in different phases of life cycle, the changes taking place in these predicted protein-protein interaction interfaces were followed as a function of maturation process of the virus. Besides changing the current notion about the presence of only homodimers in the mature viral coat, the present analysis indicated presence of a proline-rich motif at the protein-protein interaction interface of the coat protein. Investigating the conservation status of these seemingly functionally crucial residues across other members of flaviviridae family enabled dissecting common mechanisms used for infections by these viruses. Conclusions Thus, using computational approach the present analysis has provided better insights into the preexisting low resolution structures of virus assemblies, the findings of which can be made use of in designing effective antivirals against these deadly human pathogens.

Nanostructured and nanolayer coatings based on nitrides of the metals structure study and structure and composition standard samples set development

Directory of Open Access Journals (Sweden)

E. B. Chabina

2014-01-01

Full Text Available Researches by methods of analytical microscopy and the x-ray analysis have allowed to develop a set of standard samples of composition and structure of the strengthening nanostructured and nanolayer coatings for control of the strengthening nanostructured and nanolayer coatings based on nitrides of the metals used to protect critical parts of the compressor of the gas turbine engine from dust erosion, corrosion and oxidation.

Protective properties and structure of amorphous alumosilicophosphate coatings for niobium alloys

International Nuclear Information System (INIS)

Sichinava, M.A.; Kobyakov, V.P.; Sedmale, G.P.

2000-01-01

Results of thermal tests of niobium alloy samples with a protective coating in gas media with different content of oxygen are presented. Microhardness of the metal under the coating and of the coating as such prior to and after thermal testing was studied. Near the contact areas of the metal and coating were studied using electron microscopy, X-ray diffraction microprobe and X-ray phase analyses. Information on the structure, elementary and phase compositions of the near the contact areas was obtained. The processes occurring during formation and subsequent long-term annealing of the coating, which give rise to structural changes in the coating providing its adhesion to substrate and high protective efficiency, were interpreted [ru

D. C. plasma-sprayed coatings of nano-structured alumina-titania-silica

CERN Document Server

Jiang Xian Liang

2002-01-01

nano-crystalline powders of omega(Al sub 2 O sub 3) = 95%, omega(TiO sub 2) = 3%, and omega(SiO sub 2) = 2%, were reprocessed into agglomerated particles for plasma spraying, by using consecutive steps of ball milling, slurry forming, spray drying, and heat treatment. D.C. plasma was used to spray the agglomerated nano-crystalline powders, and resultant coatings were deposited on the substrate of stainless steel. Scanning electron microscopy (SEM) was used to examine the morphology of the agglomerated powders and the cross section of the alumina-titania-silica coatings. Experimental results show that the agglomerated nano-crystalline particles are spherical, with a size from (10-90) mu m. The flow ability of the nano-crystalline powders is greatly improved after the reprocessing. The coatings deposited by the plasma spraying are mainly of nano-structure. Unlike conventional plasma-sprayed coatings, no laminar layer could be found in the nano-structured coatings. Although the nano-structured coatings have a lo...

Quality control of fireproof coatings for reinforced concrete structures

Science.gov (United States)

Gravit, Marina; Dmitriev, Ivan; Ishkov, Alexander

2017-10-01

The article analyzes methods of quality inspection of fireproof coatings (work flow, measuring, laboratory, etc.). In modern construction there is a problem of lack of distinct monitoring for the fire protection testing. There is a description of this testing for reinforced concrete structures. The article shows the results of calculation quality control of hatches as an example of fireproof coating for reinforced concrete structures.

Oxidation resistance coating for niobium base structural composites

International Nuclear Information System (INIS)

Tabaru, T.; Shobu, K.; Kim, J.H.; Hirai, H.; Hanada, S.

2003-01-01

Oxidation behavior of Al-rich Mo(Si,Al) 2 base alloys, which is a candidate material for the oxidation resistance coating on Nb base structural composites, were investigated by thermogravimetry. The Mo(Si,Al) 2 base alloys containing Mo 5 (Si,Al) 3 up to about 10 vol% exhibits excellent oxidation resistance at temperatures ranging from 780 to 1580 K, particularly at 1580 K due to continuous Al 2 O 3 layer development. To evaluate the applicability of the Mo(Si,Al) 2 base coating, plasma spraying on Nb base composites were undertaken. However, interface reaction layer was found to form during the following heat treatment. Preparation of Mo(Si,Al) 2 /Al 2 O 3 /Nb layered structures via powder metallurgical process was attempted to preclude diffusion reaction between coating and substrate. (orig.)

The structure of the COPII transport-vesicle coat assembled on membranes.

Science.gov (United States)

Zanetti, Giulia; Prinz, Simone; Daum, Sebastian; Meister, Annette; Schekman, Randy; Bacia, Kirsten; Briggs, John A G

2013-09-17

Coat protein complex II (COPII) mediates formation of the membrane vesicles that export newly synthesised proteins from the endoplasmic reticulum. The inner COPII proteins bind to cargo and membrane, linking them to the outer COPII components that form a cage around the vesicle. Regulated flexibility in coat architecture is essential for transport of a variety of differently sized cargoes, but structural data on the assembled coat has not been available. We have used cryo-electron tomography and subtomogram averaging to determine the structure of the complete, membrane-assembled COPII coat. We describe a novel arrangement of the outer coat and find that the inner coat can assemble into regular lattices. The data reveal how coat subunits interact with one another and with the membrane, suggesting how coordinated assembly of inner and outer coats can mediate and regulate packaging of vesicles ranging from small spheres to large tubular carriers. DOI:http://dx.doi.org/10.7554/eLife.00951.001.

Analysis of pellet coating uniformity using a computer scanner.

Science.gov (United States)

Šibanc, Rok; Luštrik, Matevž; Dreu, Rok

2017-11-30

A fast method for pellet coating uniformity analysis, using a commercial computer scanner was developed. The analysis of the individual particle coating thicknesses was based on using a transparent orange colored coating layer deposited on white pellet cores. Besides the analysis of the coating thickness the information of pellet size and shape was obtained as well. Particle size dependent coating thickness and particle size independent coating variability was calculated by combining the information of coating thickness and pellet size. Decoupling coating thickness variation sources is unique to presented method. For each coating experiment around 10000 pellets were analyzed, giving results with a high statistical confidence. Proposed method was employed for the performance evaluation of classical Wurster and swirl enhanced Wurster coater operated at different gap settings and air flow rates. Copyright © 2017 Elsevier B.V. All rights reserved.

Biomimetic electroactive polyimide with rose petal-like surface structure for anticorrosive coating application

Directory of Open Access Journals (Sweden)

W. F. Ji

2017-08-01

Full Text Available In this work, an electroactive polyimide (EPI coating with biomimetic surface structure of rose petal used in anticorrosion application was first presented. First of all, amino-capped aniline trimer (ACAT was synthesized by oxidative coupling reaction, followed by characterized through Fourier transform infrared spectroscooy (FTIR, liquid chromatography – mass spcerometry (LC-MS and proton nuclear magnetic resonance (1H-NMR spectroscopy. Subsequently, as-prepared ACAT was reacted with isopropylidenediphenoxy-bis(phthalic anhydride (BPADA to give electroactive poly(amic acid (EPAA. Moreover, poly(dimethylsiloxane (PDMS was used to be the soft negative template for pattern transfer from the surface of rose petal to the surface of polymer coating. The EPI coating with biomimetic structure was obtained by programmed heating the EPAA slurry casting onto the negative PDMS template. The anticorrosive performance of as-prepared biomimetic EPI coating was demonstrated by performing a series of electrochemical measurements (Tafel, Nyquist, and Bode plots upon cold-rolled steel (CRS electrode in a NaCl aqueous solution. It should be noted that the biomimetic EPI coating with rose petal-like structure was found to exhibit better anticorrosion than that of EPI without biomimetic structure. Moreover, the surface contact angle of water droplets for biomimetic EPI coating was found to be ~150°, which is significantly higher than that of EPI coating with smooth structure (~87°, indicating that the EPI coating with biomimetic structure reveals better hydrophobicity. The apparent mechanism for improved anticorrosive properties is twofold: (1 the biomimetic structure of EPI coating can repel water droplets. (2 electroactivity of EPI coating promotes the formation of densely passive layer of metal oxide on metallic surface.

Multispectral Image Analysis for Astaxanthin Coating Classification

DEFF Research Database (Denmark)

Ljungqvist, Martin Georg; Ersbøll, Bjarne Kjær; Nielsen, Michael Engelbrecht

2012-01-01

Industrial quality inspection using image analysis on astaxanthin coating in aquaculture feed pellets is of great importance for automatic production control. The pellets were divided into two groups: one with pellets coated using synthetic astaxanthin in fish oil and the other with pellets coated...

Atomic structure of a peptide coated gold nanocluster identified using theoretical and experimental studies

Science.gov (United States)

Wang, Hui; Li, Xu; Gao, Liang; Zhai, Jiao; Liu, Ru; Gao, Xueyun; Wang, Dongqi; Zhao, Lina

2016-06-01

Peptide coated gold nanoclusters (AuNCs) have a precise molecular formula and atomic structure, which are critical for their unique applications in targeting specific proteins either for protein analysis or drug design. To date, a study of the crystal structure of peptide coated AuNCs is absent primarily due to the difficulty of obtaining their crystalline phases in an experiment. Here we study a typical peptide coated AuNC (Au24Peptide8, Peptide = H2N-CCYKKKKQAGDV-COOH, Anal. Chem., 2015, 87, 2546) to figure out its atomic structure and electronic structure using a theoretical method for the first time. In this work, we identify the explicit configuration of the essential structure of Au24Peptide8, Au24(Cys-Cys)8, using density functional theory (DFT) computations and optical spectroscopic experiments, where Cys denotes cysteine without H bonded to S. As the first multidentate ligand binding AuNC, Au24(Cys-Cys)8 is characterized as a distorted Au13 core with Oh symmetry covered by two Au(Cys-Cys) and three Au3(Cys-Cys)2 staple motifs in its atomic structure. The most stable configuration of Au24(Cys-Cys)8 is confirmed by comparing its UV-vis absorption spectrum from time-dependent density-functional theory (TDDFT) calculations with optical absorption measurements, and these results are consistent with each other. Furthermore, we carry out frontier molecular orbital (FMO) calculations to elucidate that the electronic structure of Au24(Cys-Cys)8 is different from that of Au24(SR)20 as they have a different Au/S ratio, where SR represents alkylthiolate. Importantly, the different ligand coatings, Cys-Cys and SR, in Au24(Cys-Cys)8 and Au24(SR)20 cause the different Au/S ratios in the coated Au24. The reason is that the Au/S ratio is crucial in determining the size of the Au core of the ligand protected AuNC, and the size of the Au core corresponds to a specific electronic structure. By the adjustment of ligand coatings from alkylthiolate to peptide, the Au/S ratio

Structure of NiCrAlY coatings deposited on single-crystal alloy turbine blade material by laser cladding

International Nuclear Information System (INIS)

Vilar, R.; Santos, E.C.; Ferreira, P.N.; Franco, N.; Silva, R.C. da

2009-01-01

In the present work single and multiple layer NiCrAlY coatings were produced by laser cladding on (100) single-crystalline substrates of SRR99 Ni-based superalloy. Detailed structural characterisation and texture analysis by optical microscopy, scanning electron microscopy, X-ray diffraction and Rutherford backscattering showed that the NiCrAlY coatings consisted essentially of γ phase with yttrium oxide (Y 2 O 3 ) and a small proportion of yttrium-aluminum garnet (Al 5 Y 3 O 12 ) precipitated in the interdendritic regions. The coatings presented a columnar dendritic structure grown by epitaxial solidification on the substrate and inherited the single-crystalline nature and the orientation of the substrate. The coating material also showed a mosaicity and a defect density similar to those of the substrate. It can be expected that the protective effect of these coatings against oxidation is greatly enhanced compared with polycrystalline coatings because high diffusivity paths, such as grain boundaries, are eliminated in single-crystalline coatings, thus reducing mass transport through the coating.

The adhesion and tribology analysis of polycrystalline diamond coated on Si3N4 substrate

International Nuclear Information System (INIS)

Hamzah, E.; Purniawan, A.

2007-01-01

Cauliflower and octahedral structure of polycrystalline diamond was deposited on silicon nitride (Si 3 N 4 ) substrate by microwave plasma assisted chemical vapor deposition (MPACVD). In our earlier work, the effects of deposition parameters namely, % Methane (CH 4 ) diluted in hydrogen (H 2 ), microwave power and chamber pressure on surface morphology were studied. In the present work the polycrystalline diamond coating adhesion and tribology behaviour were investigated. Rockwell C hardness tester and pin-on-disk tribometer were used to determine the adhesion and tribology properties on diamond coating, respectively. The morphology of the diamond before and after indentation was observed using field emission scanning electron microscopy (FESEM). Based on the adhesion analysis results, it was found that octahedral morphology has better adhesion than cauliflower structure. It was indicated by few cracks and less peel-off than cauliflower structure of polycrystalline diamond after indentation. Based on tribology analysis, polycrystalline diamond coated on substrate has better tribology properties than uncoated substrate. (author)

Fine Structure Study of the Plasma Coatings B4C-Ni-P

Science.gov (United States)

Kornienko, E. E.; Bezrukova, V. A.; Kuz'min, V. I.; Lozhkin, V. S.; Tutunkova, M. K.

2017-12-01

The article considers structure of coatings formed of the B4C-Ni-P powder. The coatings were deposited using air-plasma spraying with the unit for annular injection of powder. The pipes from steel 20 (0.2 % C) were used as a substrate. The structure and phase composition of the coatings were studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. It is shown that high-density composite coatings consisting of boron carbide particles distributed in the nickel boride metal matrix are formed using air-plasma spraying. The areas with round inclusions characterized by the increased amount of nickel, phosphorus and boron are located around the boron carbide particles. Boron oxides and nickel oxides are also present in the coatings. Thin interlayers with amorphous-crystalline structure are formed around the boron carbide particles. The thickness of these interlayers does not exceed 1 μm. The metal matrix material represents areas with nanocrystalline structure and columnar crystals.

Structure and properties of hybrid coatings

International Nuclear Information System (INIS)

Pogrebnjak, A.D.; Vasilyuk, V.V.; Kravchenko, Yu.A.; Tyurin, Yu.N.; Alontseva, D.L.; Ponaryadov, V.V.; Ruzimov, Sh.M.

2004-01-01

Full text: This review report presents both the results obtained by the authors and those of other authors concerning investigations of structure and properties of hybrid coatings. Examples of such coatings as Al 2 O 3 /Cr/TiN/steel, TiC; TiN/Ti-V-Al; NiCr/steel; CrNiBSi/steel and others before and after electron beam irradiation had been considered. In these coatings the thickest layer was deposited using the high-velocity pulsed plasma jet, all others being deposited in vacuum by the vacuum-arc source or implanter. Advantages of the high-velocity pulsed plasma jet in comparison with other technologies had been demonstrated. A wide spectrum of analyzing methods had been applied for analyses: TEM, SEM with EDS, RBS, NRA, SIMS, XRD, tests for corrosion, wear, adhesion and hardness. The works had been funded by the Project 2M/03 54-2003 of the Ministry of Science and Education of Ukraine and STCU Project N3078

Design and optimization of coating structure for the thermal barrier coatings fabricated by atmospheric plasma spraying via finite element method

Directory of Open Access Journals (Sweden)

L. Wang

2014-06-01

Full Text Available The first prerequisite for fabricating the thermal barrier coatings (TBCs with excellent performance is to find an optimized coating structure with high thermal insulation effect and low residual stress. This paper discusses the design and optimization of a suitable coating structure for the TBCs prepared by atmospheric plasma spraying (APS using the finite element method. The design and optimization processes comply with the rules step by step, as the structure develops from a simple to a complex one. The research results indicate that the suitable thicknesses of the bond-coating and top-coating are 60–120 μm and 300–420 μm, respectively, for the single ceramic layer YSZ/NiCoCrAlY APS-TBC. The embedded interlayer (50 wt.%YSZ + 50 wt.%NiCoCrAlY will further reduce the residual stress without sacrificing the thermal insulation effect. The double ceramic layer was further considered which was based on the single ceramic layer TBC. The embedded interlayer and the upper additional ceramic layer will have a best match between the low residual stress and high thermal insulation effect. Finally, the optimized coating structure was obtained, i.e., the La2Ce2O7(LC/YSZ/Interlayer/NiCoCrAlY coating structure with appropriate layer thickness is the best choice. The effective thermal conductivity of this optimized LC/YSZ/IL/BL TBC is 13.2% lower than that of the typical single ceramic layer YSZ/BL TBC.

Structure and properties of bulk amorphous magnetically soft coatings prepared by plasma spraying

International Nuclear Information System (INIS)

Kalita, V.I.; Kekalo, I.B.; Komlev, D.I.; Taranichev, V.E.

1995-01-01

Co-Ni-Fe-Si-B composition plasma coatings consisting of amorphous disk-shaped particles forming the bulk of a coating, of crystalline particles and of a threshold space, were studied. Iron and metalloid distribution heterogeneous by the thickness represents a peculiar feature for coating amorphous particles. Structure of coatings and their magnetic properties depend on some technological parameters. Conclusion is made that at annealing the variation of magnetic properties is determined by the processes of directed ordering and stratification of amorphous phase, while the low level of the initial magnetic properties of coatings is caused alongside with structure peculiarities, by occurrence of independent fine-dispersive domain structure in each disk-shaped amorphous phase. 14 refs., 8 figs., 6 tabs

Diamond coating in accelerator structure

International Nuclear Information System (INIS)

Lin, X.E.

1998-08-01

The future accelerators with 1 GeV/m gradient will give rise to hundreds of degrees instantaneous temperature rise on the copper surface. Due to its extraordinary thermal and electric properties, diamond coating on the surface is suggested to remedy this problem. Multi-layer structure, with the promise of even more temperature reduction, is also discussed, and a proof of principle experiment is being carried out

Spin coated versus dip coated electrochromic tungsten oxide films: Structure, morphology, optical and electrochemical properties

International Nuclear Information System (INIS)

Deepa, M.; Saxena, T.K.; Singh, D.P.; Sood, K.N.; Agnihotry, S.A.

2006-01-01

A sol-gel derived acetylated peroxotungstic acid sol encompassing 4 wt.% of oxalic acid dihydrate (OAD) has been employed for the deposition of tungsten oxide (WO 3 ) films by spin coating and dip coating techniques, in view of smart window applications. The morphological and structural evolution of the as-deposited spin and dip coated films as a function of annealing temperature (250 and 500 o C) has been examined and compared by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). A conspicuous feature of the dip coated film (annealed at 250 o C) is that its electrochromic and electrochemical properties ameliorate with cycling without degradation in contrast to the spin coated film for which these properties deteriorate under repetitive cycling. A comparative study of spin and dip coated nanostructured thin films (annealed at 250 o C) revealed a superior performance for the cycled dip coated film in terms of higher transmission modulation and coloration efficiency in solar and photopic regions, faster switching speed, higher electrochemical activity as well as charge storage capacity. While the dip coated film could endure 2500 color-bleach cycles, the spin coated film could sustain only a 1000 cycles. The better cycling stability of the dip coated film which is a repercussion of a balance between optimal water content, porosity and grain size hints at its potential for electrochromic window applications

Phase and structural transformations in annealed copper coatings in relation to oxide whisker growth

Energy Technology Data Exchange (ETDEWEB)

Dorogov, M.V.; Priezzheva, A.N. [Togliatti State University, Belorusskaya 14, 445667 Togliatti (Russian Federation); Vlassov, S., E-mail: vlassovs@ut.ee [Institute of Solid State Physics, University of Latvia, Kengaraga 8, LV-1063 Riga (Latvia); Kink, I.; Shulga, E. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Dorogin, L.M. [Togliatti State University, Belorusskaya 14, 445667 Togliatti (Russian Federation); Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); ITMO University, Kronverkskiy 49, 197101 Saint Petersburg (Russian Federation); Lõhmus, R. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Tyurkov, M.N.; Vikarchuk, A.A. [Togliatti State University, Belorusskaya 14, 445667 Togliatti (Russian Federation); Romanov, A.E. [Togliatti State University, Belorusskaya 14, 445667 Togliatti (Russian Federation); Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); ITMO University, Kronverkskiy 49, 197101 Saint Petersburg (Russian Federation); Ioffe Physical Technical Institute, RAS, Polytechnicheskaya 26, 194021 Saint Petersburg (Russian Federation)

2015-08-15

Highlights: • Coatings prepared by Cu microparticle electrodeposition. • Structural and phase transformation in Cu coatings annealed at 400 °C. • Annealing is accompanied by intensive growth of CuO whiskers. • Layered oxide phases (Cu{sub 2}O and CuO) in the coating are characterized. • Formation of volumetric defects in the coating is demonstrated. - Abstract: We describe structural and phase transformation in copper coatings made of microparticles during heating and annealing in air in the temperature range up to 400 °C. Such thermal treatment is accompanied by intensive CuO nanowhisker growth on the coating surface and the formation of the layered oxide phases (Cu{sub 2}O and CuO) in the coating interior. X-ray diffraction and focused ion beam (FIB) are employed to characterize the multilayer structure of annealed copper coatings. Formation of volumetric defects such as voids and cracks in the coating is demonstrated.

A comparison of models for measurable deterioration: An application to coatings on steel structures

Energy Technology Data Exchange (ETDEWEB)

Nicolai, Robin P. [Econometric Institute and Tinbergen Institute, Erasmus University Rotterdam, P.O. Box 1738, NL-3000 DR Rotterdam (Netherlands)]. E-mail: rnicolai@few.eur.nl; Dekker, Rommert [Econometric Institute, Erasmus University Rotterdam, P.O. Box 1738, NL-3000 DR Rotterdam (Netherlands); Noortwijk, Jan M. van [HKV Consultants, P.O. Box 2120, NL-8203 AC Lelystad (Netherlands); Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, P.O. Box 5031, NL-2600 GA Delft (Netherlands)

2007-12-15

Steel structures like bridges, tanks and pylons are exposed to outdoor weathering conditions. In order to prevent them from corrosion they are protected by organic coating systems. This paper focuses on modelling the deterioration of the organic coating layer that protects steel structures from corrosion. Only if there is sufficient knowledge of the condition of the coating on these structures, maintenance actions can be done in the most efficient way. Therefore the course of the deterioration of the coating system and its lifetime, which is also of importance for doing maintenance, have to be assessed accurately. In this paper, three different stochastic processes, viz. Brownian motion with non-linear drift, the non-stationary gamma process and a two-stage hit-and-grow physical process, are fitted to two real data sets. In this way we are the first who compare the three stochastic processes empirically on criteria such as goodness-of-fit, computational convenience and ease of implementation. The first data set is based on expert judgement; the second consists of inspection results. In the first case the model parameters are obtained by a least-squares approach, in the second case by the method of maximum likelihood. A meta-analysis is performed on the two-stage hit-and-grow model by means of fitting Brownian motion and gamma process to the outcomes of this model.

A comparison of models for measurable deterioration: An application to coatings on steel structures

International Nuclear Information System (INIS)

Nicolai, Robin P.; Dekker, Rommert; Noortwijk, Jan M. van

2007-01-01

Steel structures like bridges, tanks and pylons are exposed to outdoor weathering conditions. In order to prevent them from corrosion they are protected by organic coating systems. This paper focuses on modelling the deterioration of the organic coating layer that protects steel structures from corrosion. Only if there is sufficient knowledge of the condition of the coating on these structures, maintenance actions can be done in the most efficient way. Therefore the course of the deterioration of the coating system and its lifetime, which is also of importance for doing maintenance, have to be assessed accurately. In this paper, three different stochastic processes, viz. Brownian motion with non-linear drift, the non-stationary gamma process and a two-stage hit-and-grow physical process, are fitted to two real data sets. In this way we are the first who compare the three stochastic processes empirically on criteria such as goodness-of-fit, computational convenience and ease of implementation. The first data set is based on expert judgement; the second consists of inspection results. In the first case the model parameters are obtained by a least-squares approach, in the second case by the method of maximum likelihood. A meta-analysis is performed on the two-stage hit-and-grow model by means of fitting Brownian motion and gamma process to the outcomes of this model

Preparation and Application of Conductive Textile Coatings Filled with Honeycomb Structured Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Filip Govaert

2014-01-01

Full Text Available Electrical conductive textile coatings with variable amounts of carbon nanotubes (CNTs are presented. Formulations of textile coatings were prepared with up to 15 wt % of CNT, based on the solid weight of the binder. The binders are water based polyacrylate dispersions. The CNTs were mixed into the binder dispersion starting from a commercially available aqueous CNT dispersion that is compatible with the binder dispersion. Coating formulations with variable CNT concentrations were applied on polyester and cotton woven and knitted fabrics by different textile coating techniques: direct coating, transfer coating, and screen printing. The coatings showed increasing electrical conductivity with increasing CNT concentration. The coatings can be regarded to be electrically conductive (sheet resistivity<103 Ohm/sq starting at 3 wt% CNT. The degree of dispersion of the carbon nanotubes particles inside the coating was visualized by scanning electron microscopy. The CNT particles form honeycomb structured networks in the coatings, proving a high degree of dispersion. This honeycomb structure of CNT particles is forming a conductive network in the coating leading to low resistivity values.

Morphological and Structural Analysis of Nano-hydroxyapatite (n-hap) Coatings Electrodeposited on Titanium Substrate : Effect of Deposition Solution Concentration

International Nuclear Information System (INIS)

Nik Norziehana Che Isa; Norjanah Yury; Yusairie Mohd

2011-01-01

Various concentration of deposition solutions containing CaCl 2 and NH 4 H 2 PO 4 (with Ca/P ratio equal to 1.67) were used to study the effect of deposition solution concentration on the surface morphology and structure of Hydroxyapatite (HAp) coatings. Each HAp coating was deposited onto Ti substrate by applying a constant potential of 1.5 V (vs Ag/ AgCl) at 80 degree Celsius. The formation of HAp coatings was confirmed by FTIR and XRD analyses. Various morphologies consisting of HAp nanoparticles were produced from different deposition solutions as observed by SEM. The concentration of deposition solution has significantly affected the morphology of n-HAp coatings. (author)

Refractory Coated/Lined Low Density Structures, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This project addresses the development of refractory coated or lined low density structures applicable for advanced future propulsion system technologies. The...

Structure, properties and wear behaviour of multilayer coatings consisting of metallic and covalent hard materials, prepared by magnetron sputtering

International Nuclear Information System (INIS)

Schier, V.

1995-12-01

Novel multilayer coatings with metallic and covalent layer materials were prepared by magnetron sputtering and characterised concerning structure, properties and application behaviour. At first single layer coatings were deposited for the determination of the material properties. To evaluate relations between structure and properties of the multilayer coatings, different multilayer concepts were realised: - coatings consisting of at most 7 layers of metallic hard materials, - 100-layer coatings consisting of metallic and covalent hard materials, - TiN-TiC multilayer coatings with different numbers of layers (between 10 and 1000), - 150-layer coatings, based on TiN-TiC multilayers, with thin ( 4 C, AlN, SiC, a:C, Si 3 N 4 , SiAlON). X-rays and electron microscopic analysis indicate in spite of nonstoichiometric compositions single phase crystalline structures for nonreactively and reactively sputtered metastable single layer Ti(B,C)-, Ti(B,N)- and Ti(B,C,N)-coatings. These single layer coatings show excellent mechanical properties (e.g. hardness values up to 6000 HV0,05), caused by lattice stresses as well as by atomic bonding conditions similar to those in c:BN and B 4 C. The good tribological properties shown in pin-on-disk-tests can be attributed to the very high hardness of the coatings. The coatings consisting of at most 7 layers of metallic hard materials show good results mainly for the cutting of steel Ck45, due to the improved mechanical properties (e.g. hardness, toughness) of the multilayers compared to the single layer coatings. This improvement is caused by inserting the hard layer materials and the coherent reinforcement of the coatings. (orig.)

Improved irradiation tolerance of reactive gas pulse sputtered TiN coatings with a hybrid architecture of multilayered and compositionally graded structures

Science.gov (United States)

Liang, Wei; Yang, Jijun; Zhang, Feifei; Lu, Chenyang; Wang, Lumin; Liao, Jiali; Yang, Yuanyou; Liu, Ning

2018-04-01

This study investigates the improved irradiation tolerance of reactive gas pulse (RGP) sputtered TiN coatings which has hybrid architecture of multilayered and compositionally graded structures. The multilayered RGP-TiN coating is composed of hexagonal close-packed Ti phase and face-centred cubic TiN phase sublayers, where the former sublayer has a compositionally graded structure and the latter one maintains constant stoichiometric atomic ratio of Ti:N. After 100 keV He ion irradiation, the RGP-TiN coating exhibits improved irradiation resistance compared with its single layered (SL) counterpart. The size and density of He bubbles are smaller in the RGP-TiN coating than in the SL-TiN coating. The irradiation-induced surface blistering of the coatings shows a similar tendency. Meanwhile, the irradiation hardening and adhesion strength of the RGP-TiN coatings were not greatly affected by He irradiation. Moreover, the irradiation damage tolerance of the coatings can be well tuned by changing the undulation period number of N2 gas flow rate. Detailed analysis suggested that this improved irradiation tolerance could be related to the combined contribution of the multilayered and compositionally graded structures.

Structural and corrosion characterization of hydroxyapatite/zirconium nitride-coated AZ91 magnesium alloy by ion beam sputtering

Energy Technology Data Exchange (ETDEWEB)

Kiahosseini, Seyed Rahim, E-mail: rkiahoseyni@yahoo.com [Young Researchers and Elite Club, Damghan Branch, Islamic Azad University, Damghan (Iran, Islamic Republic of); Afshar, Abdollah [Department of Material Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mojtahedzadeh Larijani, Majid [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Yousefpour, Mardali [Faculty of Materials and Metallurgical Engineering, Semnan University, Semnan, 35131-19111 (Iran, Islamic Republic of)

2017-04-15

Highlights: • The thickness of HA coatings increase by ion beam sputtering time. • The residual strain in HA structure decrease by deposition time increment. • Crystallite size of HA coatings increase by deposition time increment. • The best corrosion resistance occurs at intermediate deposition time. - Abstract: The adhesion of hydroxyapatite (HA) as a coating for the AZ91 magnesium alloy substrate can be improved by using the sputtering method and an intermediate layer, such as ZrN. In this study, HA coatings were applied on ZrN intermediate layers at a temperature of 300 °C for 180, 240, 300, 360, and 420 min by ion beam sputtering. A profilometer device was used to study the HA coating thickness, which changed from 2 μm for the 180-min deposition to 4.7 μm for 420-min deposition. The grazing incidence X-ray diffraction analysis method and the Williamson–Hall analysis were used for structural investigation. As the deposition time increased, the crystalline size increased from 50 nm to 690 nm. However, given sufficient time for stress relief on the coating structure, the lattice strain values were close to zero. Energy-dispersive X-ray spectroscopy results showed that the Ca/P ratio ranged from 1.73 to 1.81. The external indentation method was used to evaluate the coating adhesion to the substrate. The slope of curve for applied force changes versus the radius of cracks in the coating (dP/dr) varied in the range of 0.2–0.07 by the deposition time, indicating that the adhesion increased with the increase in coating thickness. The potentiodynamic polarization technique was used to study the corrosion behavior. With increasing deposition time, the corrosion potential of samples did not show a significant change, and the corrosion potential of all samples (coated and uncoated substrates) was more positive than approximately 55 mV. When the deposition time increased to 360 min, the corrosion current density decreased from 5.5 μA/cm{sup 2} to 0.33 �

Fabrication and characterization of SiC and ZrC composite coating on TRISO coated particle

Energy Technology Data Exchange (ETDEWEB)

Lee, H. G.; Lee, S. H.; Kim, D. J.; Park, J. Y.; Kim, W. J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

SiC coating is widely suggested as structural materials for nuclear application due to its excellent high irradiation resistance properties and high temperature mechanical properties. SiC coating on TRistructural-ISOtropic (TRISO) coated fuel particles plays an important role as a protective layer from radioactive fission gas and a mechanical structural layer. TRISO coating layer was deposited on a spherical particle by a FBCVD method. The ZrO{sub 2} spherical particles were used as a simulant kernel. TRISO coating layers consisting of a porous buffer layer, an inner PyC layer were sequentially deposited before depositing SiC or ZrC coating layer. In order investigate the phase of each composite coating layer, Raman analysis was conducted. SiC, ZrC coating and SiC/ZrC composite coating on spherical particle were successfully deposited via FBCVD method by adjusting source gas flow rate. In the SiC and ZrC composite coating, SiC phase and ZrC phase were observed by XRD and SEM analysis. In the condition of 100 sccm of ZrCl{sub 4}, 25 sccm of CH{sub 4}, and 30 sccm of MTS, only two phases of SiC and ZrC were observed and two phases are located with clean grain boundary.

The chemistry and structure of nickel–tungsten coatings obtained by pulse galvanostatic electrodeposition

International Nuclear Information System (INIS)

Argañaraz, M.P. Quiroga; Ribotta, S.B.; Folquer, M.E.; Zelaya, E.; Llorente, C.; Ramallo-López, J.M.; Benítez, G.; Rubert, A.; Gassa, L.M.; Vela, M.E.; Salvarezza, R.C.

2012-01-01

A detailed characterization of electrodeposited Ni-W coatings prepared by pulse electrodeposition on steel and copper substrates is presented. The coatings were obtained at high current pulse frequency and show high microhardness and absence of brittleness. The surface of the coating consists of nanometer sized crystals forming a cauliflower-like structure protected by a mixture of nickel and tungsten oxides. The cauliflower structure is preserved into the bulk coating that exhibits an average composition ≈70 at% Ni-30 at% W. Different phases are observed in the bulk structure: a W-rich amorphous phase (≈40%) and Ni-rich crystalline phases (≈60%). The crystalline phases consist of crystalline domains ≈7 nm in size of Ni(W) (fcc) solid solution (12 at% W content) and a minor Ni 4 W component (less than 10%). The amorphous phase exhibits a less compact Ni-W structure where some amount of C could also be present. Oxidized W species cannot be detected in the bulk coating, thus discarding the presence of significant amounts of tungsten carbide, tungstates or citrate–tungsten complexes. Our results shed light on controversial points related to the chemical composition and demonstrate the complex structure of this system.

Dry rotary swaging with structured and coated tools

Science.gov (United States)

Herrmann, Marius; Schenck, Christian; Kuhfuss, Bernd

2018-05-01

Rotary swaging is a cold bulk forming process for manufacturing of complex bar and tube profiles like axles and gear shafts in the automotive industry. Conventional rotary swaging is carried out under intense use of lubricant usually based on mineral oil. Besides lubrication the lubricant fulfills necessary functions like lubrication, flushing and cooling, but generates costs for recycling, replacement and cleaning of the workpieces. Hence, the development of a dry process design is highly desirable, both under economic and ecological points of view. Therefore, it is necessary to substitute the functions of the lubricant. This was realized by the combination of newly developed a-C:H:W coating systems on the tools to minimize the friction and to avoid adhesion effects. With the application of a deterministic structure in the forging zone of the tools the friction conditions are modified to control the axial process forces. In this study infeed rotary swaging with functionalized tools was experimentally investigated. Therefore, steel and aluminum tubes were formed with and without lubricant. Different structures which were coated and uncoated were implemented in the reduction zone of the tools. The antagonistic effects of coating and structuring were characterized by measuring the axial process force and the produced workpiece quality in terms of roundness and surface roughness. Thus, the presented results allow for further developments towards a dry rotary swaging process.

Environmentally Preferable Coatings for Structural Steel Project

Science.gov (United States)

Lewis, Pattie L. (Editor)

2014-01-01

The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described a the "launch support and infrastructure modernization program" in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the objective of this project is to determine the feasibility of environmentally friendly corrosion resistant coatings for launch facilities and ground support equipment. The focus of the project is corrosion resistance and survivability with the goal to reduce the amount of maintenance required to preserve the performance of launch facilities while reducing mission risk. Number of facilities/structures with metallic structural and non-structural components in a highly corrosive environment. Metals require periodic maintenance activity to guard against the insidious effects of corrosion and thus ensure that structures meet or exceed design or performance life. The standard practice for protecting metallic substrates in atmospheric environments is the application of corrosion protective coating system.

Chemical and structural analyses of subsurface crevices formed during spontaneous deposition of cerium-based conversion coatings

Energy Technology Data Exchange (ETDEWEB)

Heller, Daimon K, E-mail: dkheller@mmm.com; Fahrenholtz, William G., E-mail: billf@mst.edu; O' Keefe, Matthew J., E-mail: mjokeefe@mst.edu

2011-11-15

Subsurface crevices formed during the deposition of cerium-based conversion coatings were analyzed in cross-section to assess the effect of deposition and post-treatment on the structure and chemistry of phases present. An Al-O containing phase, believed to be amorphous Al(OH){sub 3}, was formed in crevices during coating deposition. Analysis by energy dispersive X-ray spectroscopy revealed the presence of up to 1.6 at.% chlorine within the Al-O phase, which was likely a product of soluble chlorides that were present in the coating solution. Cerium was not detected within crevices. After post-treatment in an 85 deg. C aqueous phosphate solution, the chloride concentration was reduced to {<=} 0.30 at.% and electron diffraction of the Al-O phase produced ring patterns, indicating it had crystallized. Some diffraction patterns could be indexed to gibbsite (Al(OH){sub 3}), but others are believed to be a combination of hydrated aluminum hydroxides and/or oxides. Aluminum phosphate was not identified. Separately from its effect on cerium-based conversion coatings, phosphate post-treatment improved the corrosion resistance of Al 2024-T3 substrates by acting to crystallize Al(OH){sub 3} present on interior surfaces of crevices and by reducing the chloride concentration in this phase. - Highlights: {yields} Analysis of subsurface crevices formed during deposition of Ce-based conversion coatings. {yields} Phosphate post-treatment improved corrosion protection in salt spray testing. {yields} Post-treatment affected the composition and structure of regions within crevices. {yields} Crystallized Al(OH){sub 3} within crevices acted as a more effective barrier to chloride ions.

Near-edge X-ray absorption fine structure studies of Cr{sub 1−x}M{sub x}N coatings

Energy Technology Data Exchange (ETDEWEB)

Mahbubur Rahman, M. [School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150 (Australia); Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh); Duan, Alex [School of Chemistry, The University of Melbourne, Parkville, VIC 3010 (Australia); Jiang, Zhong-Tao, E-mail: Z.Jiang@murdoch.edu.au [School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150 (Australia); Xie, Zonghan [School of Mechanical Engineering, University of Adelaide, SA 5005 (Australia); School of Engineering, Edith Cowan University, WA 6027 (Australia); Wu, Alex [School of Chemistry, The University of Melbourne, Parkville, VIC 3010 (Australia); Amri, Amun [Department of Chemical Engineering, Riau University, Pekanbaru (Indonesia); Cowie, Bruce [Australian Synchrotron, 800 Blackburn Rd., Clayton, VIC 3168 (Australia); Yin, Chun-Yang [Chemical and Analytical Sciences, Murdoch University, Murdoch, WA 6150 (Australia)

2013-11-25

Highlights: •Al or Si is doped on CrN and AlN coatings using magnetron sputtering system. •NEXAFS analysis is conducted to measure the Al and Si K-edges, and chromium L-edge. •Structural evolution of CrN matrix with addition of Al or Si element is investigated. -- Abstract: Cr{sub 1−x}M{sub x}N coatings, with doping concentrations (Si or Al) varying from 14.3 to 28.5 at.%, were prepared on AISI M2 tool steel substrates using a TEER UDP 650/4 closed field unbalanced magnetron sputtering system. Near-edge X-ray absorption fine structure (NEXAFS) characterization was carried out to measure the aluminum and silicon K-edges, as well as chromium L-edge, in the coatings. Two soft X-ray techniques, Auger electron yield (AEY) and total fluorescence yield (TFY), were employed to investigate the surface and inner structural properties of the materials in order to understand the structural evolution of CrN matrix with addition of Al (or Si) elements. Investigations on the local bonding states and grain boundaries of the coatings, using NEXAFS technique, provide significant information which facilitates understanding of the local electronic structure of the atoms and shed light on the origins of the high mechanical strength and oxidation resistance of these technologically important coatings.

Model for electromagnetic field analysis of superconducting power transmission cable comprising spiraled coated conductors

International Nuclear Information System (INIS)

Takeuchi, Katsutoku; Amemiya, Naoyuki; Nakamura, Taketsune; Maruyama, Osamu; Ohkuma, Takeshi

2011-01-01

Since the superconductor layers of YBCO-coated conductors are very thin, the ac loss of coated conductors is dominated by the magnetic flux density normal to the conductor face. In cables, most of the normal magnetic flux component is generated near gaps between coated conductors. Although the effects of gaps are significant, there are few reports on the electromagnetic field analysis of cables with spiral structures carried out while taking the gap effect into consideration. In a finitely long cable with a spiral structure, the electromagnetic field is naturally periodic along the cable axis. In a two-layer cable, the simplest period along the cable axis is the least common multiple of the spiral pitches in the inner and outer layers. However, we verified that there is a shorter period, and the same electromagnetic field distribution appears in all conductors of the same layer. Using these periodicities, we developed a three-dimensional model for the analysis of two-layer cables with a spiral structure. Current distributions of cables were analyzed using this model, and ac losses were calculated. In addition, these results were compared with ac losses calculated by two-dimensional analysis performed on the cross section of a cable. It was verified that the ac loss in a cable is correctly calculated by the 2D model when the spiral pitch is long enough. However, in the case of a tightly twisted cable, the ac losses calculated by the 2D model include some errors caused by an approximation in which the spiral structure is ignored.

The fabrication, nano/micro-structure, heat- and wear-resistance of the superhydrophobic PPS/PTFE composite coatings.

Science.gov (United States)

Wang, Huaiyuan; Zhao, Jingyan; Zhu, Youzhuang; Meng, Yang; Zhu, Yanji

2013-07-15

A simple engineering method was used to fabricate stability and wear-resistance of superhydrophobic PPS-based PPS/PTFE surfaces through nano/micro-structure design and modification of the lowest surface energy groups (-CF2-), which was inspired by the biomimic lotus leaves. The hydrophobic properties and wear-resistance of the coatings were measured by a contact angle meter and evaluated on a pin-on-disk friction and wear tester, respectively. Moreover, the surfaces of the PPS/PTFE composite coatings were investigated by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and thermogravimetry (TG) analysis. Results showed that the highest contact angle of the PPS/PTFE surface, with papillae-like randomly distributed double-scale structure, could reach up to 162°. When 1 wt.% PDMS was added, the highest contact angle could hold is 172°. The coatings also retained superhydrophobicity, even under high temperature environment. The investigation also indicated that the coatings were not only superhydrophobic but also oleophobic behavior at room temperature, such as the crude oil, glycerol, and oil-water mixture. The PPS/45%PTFE coatings had more stable friction coefficient and excellent wear-resistance (331,407 cycles) compared with those with less than 45% of PTFE. Copyright © 2012 Elsevier Inc. All rights reserved.

Growth and structure of hyperthin SiO2 coatings on polymers

International Nuclear Information System (INIS)

Dennler, G.; Houdayer, A.; Segui, Y.; Wertheimer, M.R.

2001-01-01

Transparent inorganic oxide coatings on polymers are playing an increasingly important role in pharmaceutical, food, and beverage packaging, and more recently in encapsulation of organic, light-emitting display devices. Such coatings are being prepared by physical or by chemical vacuum-deposition methods. They possess barrier properties against permeation of gases or vapors when they are thicker than a certain critical thickness, d c ; for d c , the 'oxygen transmission rate' (in standard cm 3 /m 2 /day/bar), for example, is roughly the same as that of the uncoated polymer. This fact is commonly attributed in the literature to a 'nucleation' phase of the coating's growth, during which it is thought to present an island-like structure. In order to test this hypothesis, we have deposited hyperthin SiO 2 coatings on various flexible polymeric substrates using plasma-enhanced chemical vapor deposition. The film thicknesses investigated here, well below d c (typically in the range 1-10 nm), were determined by Rutherford backscattering spectroscopy, which allows us to determine the surface concentration of silicon. This was found to be a linear function of the deposition time, t, for t≥0.5 s. Then, combining reactive ion etching in oxygen plasma with scanning electron and optical microscopy, we have been able to characterize the structure of the coatings: even for d≤2 nm, no island structure has been observed. Instead, we found continuous coatings which contain large concentrations, n, of tiny pinhole defects (with typical radii in the range of tens of nanometers), where n increases with decreasing d. These assertions are confirmed by grazing angle (80 deg. ) angle-resolved x-ray photoelectron spectroscopy, which shows that even for d=2 nm, the structural features of the polymer substrate cannot be detected

Structural changes of polymer-coated microgranules and excipients on tableting investigated by microtomography using synchrotron X-ray radiation.

Science.gov (United States)

Kajihara, Ryusuke; Noguchi, Shuji; Iwao, Yasunori; Suzuki, Yoshio; Terada, Yasuko; Uesugi, Kentaro; Itai, Shigeru

2015-03-15

Multiple-unit tablets consisting of polymer-coated microgranules and excipients have a number of advantageous pharmaceutical properties. Polymer-coated microgranules are known to often lose their functionality because of damage to the polymer coating caused by tableting, and the mechanism of polymer coating damage as well as the structural changes of excipients upon tableting had been investigated but without in-situ visualization and quantitative analysis. To elucidate the mechanism of coating damage, the internal structures of multiple-unit tablets were investigated by X-ray computed microtomography using synchrotron X-rays. Cross sectional images of the tablets with sub-micron spatial resolution clearly revealed that void spaces remained around the compressed excipient particles in the tablets containing an excipient composed of cellulose and lactose (Cellactose(®) 80), whereas much smaller void spaces remained in the tablets containing an excipient made of sorbitol (Parteck(®) SI 150). The relationships between the void spaces and the physical properties of the tablets such as hardness and disintegration were investigated. Damage to the polymer coating in tablets was found mainly where polymer-coated microgranules were in direct contact with each other in both types of tablets, which could be attributed to the difference in hardness of excipient particles and the core of the polymer-coated microgranules. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of Polydimethylsiloxane-Modified Polyurethane and the Structure and Properties of Its Antifouling Coatings

Directory of Open Access Journals (Sweden)

Zhan-Ping Zhang

2018-04-01

Full Text Available Polydimethylsiloxane (PDMS could be used to improve the antifouling properties of the fouling release coatings based on polyurethane (PU. A series of polydimethylsiloxane-modified polyurethane coatings were synthesized with various PDMS contents, using the solvent-free method. The effects of PDMS content and seawater immersion on the chain structure and surface morphology were investigated by confocal laser scanning microscopy (CLSM, atomic force microscopy (AFM, Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA and X-ray diffraction (XRD. Based on the measurements of contact angles of deionized water and diiodomethane, surface free energies of the coatings were estimated according to the Owens two-liquid method. The PDMS-modified polyurethane exhibited lower surface free energy and a lower glass transition temperature than polyurethane. The presence of PDMS increased the degree of microphase separation, and enhanced the water resistance of the coatings. The optimum amount of PDMS reduced the elastic modulus and increased the ductility of the coating. The presence of PDMS benefited the removal of weakly attached organisms. Panel tests in the Yellow Sea demonstrated the antifouling activity of the PDMS-modified polyurethane.

Ion Beam Analysis, structure and corrosion studies of nc-TiN/a-Si{sub 3}N{sub 4} nanocomposite coatings deposited by sputtering on AISI 316L

Energy Technology Data Exchange (ETDEWEB)

García, J. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jal. 45101 (Mexico); Canto, C.E. [Instituto de Física, UNAM, Avenida de la Investigación S/N, Coyoacán, México, D.F. 04510 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jal. 45101 (Mexico); Andrade, E., E-mail: andrade@fisica.unam.mx [Instituto de Física, UNAM, Avenida de la Investigación S/N, Coyoacán, México, D.F. 04510 (Mexico); Rodríguez, E.; Jiménez, O. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jal. 45101 (Mexico); Solis, C.; Lucio, O.G. de [Instituto de Física, UNAM, Avenida de la Investigación S/N, Coyoacán, México, D.F. 04510 (Mexico); Rocha, M.F. [ESIME-Z, Instituto Politécnico Nacional, ALM Zacatenco, México, D.F. 07738 (Mexico)

2014-07-15

In this work, nanocomposite coatings of nc-TiN/a-Si{sub 3}N{sub 4}, were deposited on AISI 316L stainless steel substrate by a DC and RF reactive magnetron co-sputtering technique using an Ar–N{sub 2} plasma. The structure of the coatings was characterized by means of XRD (X-ray Diffraction). The substrate and coating corrosion resistance were evaluated by potentiodynamic polarization using a Ringer solution as electrolyte. Corrosion tests were conducted with the purpose to evaluate the potential of this coating to be used on biomedical alloys. IBA (Ion Beam Analysis) techniques were applied to measure the elemental composition profiles of the films and, XPS (X-ray Photoelectron Spectroscopy) were used as a complementary technique to obtain information about the compounds present in the films. The nanocomposite coatings of nc-TiN/a-Si{sub 3}N{sub 4} show crystalline (TiN) and amorphous (Si{sub 3}N{sub 4}) phases which confer a better protection against the corrosion effects compared with that of the AISI 316L.

Comparative Study of Micro- and Nano-structured Coatings for High-Temperature Oxidation in Steam Atmospheres

OpenAIRE

Pérez, F.J.; Castañeda, I.; Hierro, M.P.; Escobar Galindo, R.; Sánchez-López, J.C.; Mato, S.

2014-01-01

For many high-temperature applications, coatings are applied in order to protect structural materials against a wide range of different environments: oxidation, metal dusting, sulphidation, molten salts, steam, etc. The resistance achieved by the use of different kind of coatings, such as functionally graded material coatings, has been optimized with the latest designs. In the case of supercritical steam turbines, many attempts have been made in terms of micro-structural coatings design, main...

Development and characterization of nano structured hard coatings for high performance tools by using PVD technique

International Nuclear Information System (INIS)

Irfan, M.; Alam, S.; Hassan, Z.; Iftikhar, F.; Khadim, S.

2006-01-01

No doubt hard coatings nave major applications in high performance cutting tools in order to improve tribological and mechanical properties of these tools since last years. The actual top development in this regard is the development of PVD based AlTiN coatings and their supplementation with nano. layers. In present these nano coatings are replaced by nano composites along with an additional development of Multilayer Nano structured coatings. This PVD based nano structured coating development optimized by process parameters, crystalline structure and deposition in multilayer. These coating are definitely produced by combination of ARC and Sputtering with filtration of arc droplets. It is studied that the properties like oxidation resistance, wear resistance and resistance against chemical reaction may be obtained by alloying additions of different elements. This paper presents different development stages and Process parameters for- producing high performance Nanostructure coatings and including adhesion test by using Kalomax system for determination of adhesion strength of these coatings and coating thickness measurements by using image analyzer system. Results and conclusions are showing the optimum values for better coatings for different applications. (author)

9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments.

Science.gov (United States)

Dodonova, Svetlana O; Aderhold, Patrick; Kopp, Juergen; Ganeva, Iva; Röhling, Simone; Hagen, Wim J H; Sinning, Irmgard; Wieland, Felix; Briggs, John A G

2017-06-16

COPI coated vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 Å resolution. We also obtained a 2.57 Å resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate vesicle assembly while others regulate coat disassembly.

Anti-wetting Cu/Cr coating with micro-posts array structure fabricated by electrochemical approaches

International Nuclear Information System (INIS)

Zhou, Yufeng; Hang, Tao; Li, Feng; Li, Ming

2013-01-01

Microposts structured Cu/Cr multilayer coating was prepared by a simple two-step approach combining electroless and electro deposition. Surface morphologies of the as-prepared Cu/Cr multilayer coating characterized by field emission scanning electron microscopy show that this multilayer coating exhibits micro-posts arrayed structure with a layer of Cr uniformly covering the circular conical surface of Cu micro-cones array. The wettability test shows that the contact angle of Cu/Cr multilayer surface with water drop can be greater than 140° by optimizing the electrodeposition time of Cr. The mechanism of hydrophobicity of both the micro-cones arrayed and micro-posts arrayed structures was briefly discussed by comparing two different wetting modes. Due to its good anti-wetting property and unique structure, the micro-posts arrayed Cu/Cr multilayer coating is expected for extensive practical applications.

Structure and phase composition of titanium nitride coating on austenitic steel

International Nuclear Information System (INIS)

Dubovitskaya, N.V.; Kolenchenko, L.D.; Larikov, L.N.

1989-01-01

Structure and phase composition of titanium nitride coating deposited on 08Kh18N10T steel substrate using ''Bulat'' device are studied. Use of complex investigation methods permitted despite small coating thickness (1μm) to aquire information on hardness, porosity, to study phase composition in all coating thickness. The surface layer (∼0.1 μm) consists of ε-Ti 2 N, TiN 0.6 , TiC 0.35 , that is formed with carbon participation from oil vacuum. In more deeper layers beside ε-Ti 2 N TiC 0.14 N 0.77 is present. Effect of carbon diffusion from substrate to forming coating is stated. Gradient of element concentrations in the substrate-coating interface causes recrystallization of austenite

A MICROPOROUS COATING OR STRUCTURE AND A PROCESS FOR PRODUCING IT

DEFF Research Database (Denmark)

2008-01-01

A microporous coating or structure is established as a thin metallic layer by deposition of one or more alloys on a metallic substrate, each of said alloys consisting of two or more phases, one of which can be selectively dissolved in a solution that will not significantly attack the other phase...... or phases. Such microporous coatings or structures are useful in the production of various product types, such as fuel cells, catalysts, microfilters, heat exchangers, micro-components and heat transfer devices....

How Does Amino Acid Ligand Modulate Au Core Structure and Characteristics in Peptide Coated Au Nanocluster?

Science.gov (United States)

Li, Nan; Li, Xu; Zhao, Hongkang; Zhao, Lina

2018-03-01

The atomic structures and the corresponding physicochemical properties of peptide coated Au nanoclusters determine their distinctive biological targeting applications. To learn the modulation of amino acid ligand on the atomic structure and electronic characteristics of coated Au core is the fundamental knowledge for peptide coated Au nanocluster design and construction. Based on our recent coated Au nanocluster configuration study (Nanoscale, 2016, 8, 11454), we built the typically simplified Au13(Cys-Au-Cys) system to more clearly learn the basic modulation information of amino acid ligand on Au core by the density functional theory (DFT) calculations. There are two isomers as ligand adjacent bonding (Iso1) and diagonal bonding (Iso2) to Au13 cores. The geometry optimizations indicate the adjacent bonding Iso1 is more stable than Iso2. More important, the Au13 core of Iso1 distorts much more significantly than that of Iso2 by Cys-Au-Cys bonding through the root-mean-square deviation (RMSD) analysis, which modulate their electronic characteristics in different ways. In addition, the frontier molecular orbital results of Au13(Cys-Au-Cys) isomers confirm that the Au cores mainly determine the blue shifts of Au13(Cys-Au-Cys) systems versus the original Au13 core in their UV-visible absorption spectrum studies. The configuration of Au13 core performs deformation under Cys-Au-Cys ligand modulation to reach new stability with distinct atomic structure and electronic properties, which could be the theory basis for peptide coated AuNCs design and construction.

Topology optimization for coated structures

DEFF Research Database (Denmark)

Clausen, Anders; Andreassen, Erik; Sigmund, Ole

2015-01-01

This paper presents new results within the design of three-dimensional (3D) coated structures using topology optimization.The work is an extension of a recently published two-dimensional (2D) method for including coatedstructures into the minimum compliance topology optimization problem. The high...... level of control over key parameters demonstrated for the 2D model can likewise be achieved in 3D. The effectiveness of the approach isdemonstrated with numerical examples, which for the 3D problems have been solved using a parallel topology optimization implementation based on the PETSc toolkit....

Multipactor suppression by micro-structured gold/silver coatings for space applications

Energy Technology Data Exchange (ETDEWEB)

Nistor, Valentin, E-mail: valentin.nistor@uam.es [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); González, Luis A. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Aguilera, Lydya; Montero, Isabel [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Galán, Luis [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Wochner, Ulrich [Tesat Spacecom GmbH and Co. KG,Gerberstr. 49, D-71522 Backnang (Germany); Raboso, David [European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), 2200 AG Noordwijk (Netherlands)

2014-10-01

Highlights: • Total suppression of the multipactor effect was achieved for a specific configuration of a high RF power K{sub u}-band waveguide. • Secondary emission of electrons was decreased by surfaces of high aspect ratio. • Simple techniques were used in the manufacturing of metallic microscopical rough coatings. • Surface analysis of the treatment was performed. • The RF insertion losses were improved with respect to Alodine, the standard coating for space applications. - Abstract: The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of K{sub u}-band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4–6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were

Multipactor suppression by micro-structured gold/silver coatings for space applications

International Nuclear Information System (INIS)

Nistor, Valentin; González, Luis A.; Aguilera, Lydya; Montero, Isabel; Galán, Luis; Wochner, Ulrich; Raboso, David

2014-01-01

Highlights: • Total suppression of the multipactor effect was achieved for a specific configuration of a high RF power K u -band waveguide. • Secondary emission of electrons was decreased by surfaces of high aspect ratio. • Simple techniques were used in the manufacturing of metallic microscopical rough coatings. • Surface analysis of the treatment was performed. • The RF insertion losses were improved with respect to Alodine, the standard coating for space applications. - Abstract: The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of K u -band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4–6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were

Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying

Science.gov (United States)

Nosenko, Valentyna; Strutynska, Nataliia; Vorona, Igor; Zatovsky, Igor; Dzhagan, Volodymyr; Lemishko, Sergiy; Epple, Matthias; Prymak, Oleg; Baran, Nikolai; Ishchenko, Stanislav; Slobodyanik, Nikolai; Prylutskyy, Yuriy; Klyui, Nickolai; Temchenko, Volodymyr

2015-12-01

Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The tetracalcium phosphate phase was homogeneous; the apatite phase contained defects localized on the sixfold axis and consisted of hydroxyapatite and oxyapatite. Technological factors contributing to the transformation of hydroxyapatite powder structure during coating formation by detonation spraying are discussed.

Protective coatings on structural materials for energy conversion systems

International Nuclear Information System (INIS)

John, J.T.; De, P.K.; Srinivasa, R.S.

2000-01-01

Full text: Structural Materials and Components used in coal fired energy conversion systems, crude oil refineries and coal gasification plants are subjected to degradation due to oxidation, sulfidation, carbonization and halogenation. Suitable protective coatings can significantly enhance their life. Protective coatings work by forming a highly stable, self-healing and slow growing protective scale at the operating temperatures. These scales act as barriers between the corrosive environment and the alloy and prevent degradation of the substitute. Three types of scales that provide such protection are based on Al 2 O 3 , Cr 2 O 3 and SiO 2 . Aluminide coatings are major alumina forming protecting coatings, applied on nickel, cobalt and iron base alloys. Aluminide coatings are prepared by enriching the surface of a component by aluminum. In this paper the formation of aluminide coatings of nickel, IN738, Alloy 800, Zircaloy-2 and pure iron by chemical vapor deposition has been described. In this technique, Aluminum chloride vapors from bath kept at 353-373 K are carried in a stream of hydrogen gas into a Hot Walled CVD chamber kept at 1173-1373 K. The AlCl 3 vapors were allowed to react with pure aluminum whereby aluminum sub-chlorides like AlCl and AlCl 2 are produced which deposit aluminum on the substrates. At the high temperature of the deposition, aluminum diffuses into the substrate and forms the aluminide coating. The process can be represented by the reaction Al (i) + AlCl 3(g) AlCl 2(s) + AlCl 2 (g) . XRD and optical microscopic studies have characterized the coatings. On pure nickel and Alloy 800 the coating consists of Ni 2 Al 3 and NiAl respectively. On pure iron the coatings consisted of FeAl. On Zircaloy-2, ZrAl 2 was also detected. The CVD coating process, XRD and optical microscopy data will be discussed further

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.

Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

International Nuclear Information System (INIS)

Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław; Brytan, Zbigniew

2016-01-01

Highlights: • Prediction of the properties of PVD/CVD coatings with the use of (FEM) analysis. • Stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N coatings. • The experimental values of stresses were determined on X-ray diffraction patterns. • An FEM model was established for the purpose of building a computer simulation. - Abstract: The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were

Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

Energy Technology Data Exchange (ETDEWEB)

Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław, E-mail: miroslaw.bonek@polsl.pl; Brytan, Zbigniew

2016-12-01

Highlights: • Prediction of the properties of PVD/CVD coatings with the use of (FEM) analysis. • Stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N coatings. • The experimental values of stresses were determined on X-ray diffraction patterns. • An FEM model was established for the purpose of building a computer simulation. - Abstract: The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were

Fabrication and excellent conductive performance of antimony-doped tin oxide-coated diatomite with porous structure

International Nuclear Information System (INIS)

Du Yucheng; Yan Jing; Meng Qi; Wang Jinshu; Dai Hongxing

2012-01-01

Graphical abstract: Antimony-doped tin oxide (ATO)-coated diatomite with porous structures are fabricated using the co-precipitation method. The porous ATO-coated diatomite material shows excellent conductive performance. Highlights: ► Sb-doped SnO 2 (ATO)-coated diatomite materials with porous structures are prepared. ► Sn/Sb ratio, ATO coating amount, pH value, and temperature influence resistivity. ► Porous ATO-coated diatomite materials show excellent conductive performance. ► The lowest resistivity of the porous ATO-coated diatomite sample is 10 Ω cm. - Abstract: Diatomite materials coated with antimony-doped tin oxide (ATO) were prepared by the co-precipitation method, and characterized by means of the techniques, such as X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, selected-area electron diffraction, X-ray fluorescence spectroscopy, and N 2 adsorption–desorption measurement. It was shown that the coated ATO possessed a tetragonal rutile crystal structure, and the ATO-coated diatomite materials had a multi-pore (micro- meso-, and macropores) architecture. The porous ATO-coated diatomite materials exhibited excellent electrical conductive behaviors. The best conductive performance (volume resistivity = 10 Ω cm) was achieved for the sample that was prepared under the conditions of Sn/Sb molar ratio = 5.2, Sn/Sb coating amount = 45 wt%, pH = 1.0, and reaction temperature = 50 °C. Such a conductive porous material is useful for the applications in physical and chemical fields.

Surface analysis of DLC coating on cam-tappet system

OpenAIRE

FOUVRY, Siegfried; PAGNOUX, Geoffrey; PEIGNEY, Michael; DELATTRE, Benoit; MERMAT-ROLLET, Guillaume

2013-01-01

Tribomechanical properties of diamond-like carbon (DLC) coatings make them particularly interesting for numerous applications, like automotive ones. But although DLC coatings show a generally high wear resistance, they sometimes can exhibit severe multiple wear. In this study, a surface analysis of worn coated tappets is performed, leading to a complete coupled wear scenario.

Structural ceramic coatings in composite microtruss cellular materials

International Nuclear Information System (INIS)

Bele, E.; Bouwhuis, B.A.; Codd, C.; Hibbard, G.D.

2011-01-01

Graphical abstract: The compressive strength increase per unit sleeve thickness of Al cores reinforced with Al 2 O 3 sleeves is lower than the corresponding strength increase when the same cores are reinforced with nanocrystalline Ni (n-Ni) sleeves (left). However, because anodizing is a transformative surface treatment, the Al 2 O 3 coating was able to achieve this performance increase with little overall weight penalty (right). Display Omitted Highlights: → A new type of metal/ceramic microtruss cellular composite has been created. → Reinforcing sleeves of Al 2 O 3 were deposited on low density Al microtruss cores. → Significant compressive strength increases were seen at virtually no weight penalty. → Failure mechanisms were studied by electron microscopy and finite element analysis. → Buckling, sleeve wrinkling, and coating fracture dictated the compressive strength. - Abstract: In the present study, anodizing was used to produce Al 2 O 3 coatings in a conventional 3003 aluminum alloy microtruss core; a 38.5 μm thick anodic coating provided a 143% increase in compressive strength. Finite-element analyses were used to illustrate the dependence of the compressive strength and failure mechanism on the thickness of the anodic coating. At low thicknesses the microtruss strength is dictated by global bucking of the internal struts. However, at higher thicknesses the compressive strength is controlled by coating fracture and local deformation in the hinge region of the struts. Regardless of the failure mechanism, the compressive strength of the composite microtruss increased with increasing anodic coating thickness, with very little corresponding weight penalty.

Evolution of self-organization in nano-structured PVD coatings under extreme tribological conditions

Energy Technology Data Exchange (ETDEWEB)

Fox-Rabinovich, G., E-mail: gfox@mcmaster.ca [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada); Kovalev, A. [Surface Phenomena Researches Group, CNIICHERMET, 9/23, 2-nd Baumanskaya Street, Moscow 105005 (Russian Federation); Aguirre, M.H. [Laboratory of Advanced Microscopy, Institute of Nanoscience of Aragón, University of Zaragoza, 50018 Zaragoza (Spain); Yamamoto, K. [Materials Research Laboratory, Kobe Steel Ltd, 1-5-5 Takatsuda-dai, Nishi-ku, Kobe 651-2271, Hyogo (Japan); Veldhuis, S. [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada); Gershman, I. [All-Russian Railway Research Institute, 10 Third Mytishchinskaya Street, Moscow 29851 (Russian Federation); Rashkovskiy, A. [Surface Phenomena Researches Group, CNIICHERMET, 9/23, 2-nd Baumanskaya Street, Moscow 105005 (Russian Federation); Endrino, J.L. [Albengoa Research, Energia Solar 1, Palmas Altas, Seville 41014 (Spain); Beake, B. [Micro Materials Limited, Willow House, Yale Business Village, Ellice Way, Wrexham LL13 7YL (United Kingdom); Dosbaeva, G. [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada); Wainstein, D. [Surface Phenomena Researches Group, CNIICHERMET, 9/23, 2-nd Baumanskaya Street, Moscow 105005 (Russian Federation); Yuan, Junifeng; Bunting, J.W. [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada)

2014-04-01

Highlights: • The evolution of self-organization under extreme frictional conditions has been studied. • Comprehensive characterization of the tribo-films was made using various surface analytical techniques. • During the running-in stage, mullite tribo-ceramics predominate on the surface of the nano-multilayer coating, establishing a functional hierarchy within the layer of tribo-films. • It is possible to control tribo-film evolution during self-organization by means of an increase in structural complexity and the non-equilibrium state of the surface engineered layer. - Abstract: The evolution of the self-organization process where dissipative structures are formed under the extreme frictional conditions associated with high performance dry machining of hardened steels has been studied in detail. The emphasis was on the progressive studies of surface transformations within multilayer and monolayer TiAlCrSiYN-based PVD coatings during the running-in stage of wear when self-organization process occurs. The coating layer was characterized by high resolution electron energy-loss spectroscopy (HREELS). It is shown that the nano-multilayer coating possesses higher non-equilibrium structure in comparison to the monolayer. Comprehensive studies of the tribo-films (dissipative structures) formed on the friction surface were made using a number of advanced surface characterization techniques such as X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES). The data obtained for the tribo-films was combined with the detailed TEM studies of the structural and phase transformations within the underlying coating layer. This data was related to the micro-mechanical characteristics of the coating layer and its wear resistance. It was demonstrated that the evolution of the self-organization process is strongly controlled by the characteristics of the tribo-films formed at different stages of the wear process. Within running-in stage (after

Structural characteristics of porous hydroxyapatite coating on CaO-SiO{sub 2} system glass

Energy Technology Data Exchange (ETDEWEB)

Zhang Hongquan; Yan Yuhua; Li Shipu [Wuhan Univ. of Technology (China). Biomedical and Engineering Research Center

2001-07-01

Hydroxyapatite(HA) coated CaO-SiO{sub 2} system glass composites were prepared successfully by the hydrothermal coating method at the temperature of 250 to 350 C and at pH of 7 to 9. The microstructure and phase composition were identified by XRD, FT-IR, SEM, EPMA and TEM. It is shown that HA coating possessed a porous gradient construction in the interface; HA coating and glass substrate were tightly bonded by an obvious transition. HA coating had a well-distributed porous construction on the surface layer. The interface structure, phase composition and the stability of HA coated glass composites were related with its forming process. These kinds of structure will benefit to the interface bonging strength and bone bonding strength. (orig.)

The structure of the alphinizing coat on alloy steels

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-12-01

Full Text Available In this paper results of the structure of the coat alphinizing in AlSi5 silumin on alloy steels: acid-proof 1H18N9T (X6CrNiTi18-10 and high speed SW18 (HS18-0-1 were presented. The temperature of the alphinizing bath was amounts to750±5°C, and immersion time of the element τ = 180s. It was shown, that there is the different “g” coat thickness on testing steels. On the 1H18N9T steel it amounts to g = 52μm, and on the SW18 steel – g = 203μm. Regardless of a grade of testing alloy steels the coat consist of three layers with diversified phasic structure. There is different chemical composition of coat layers on testing steels. The first layer from the base consist of AlFe phase containing alloy addictions of steels: Cr and Ni (1H18N9T and W, V and Cr (SW18. On this layer crystallize the second layer of intermetallic phases. It is the phase containing the main alloy addiction of steels: AlFeCr (1H18N9T and AlFeW (SW18. The last, outside layer consist of silumin containing AlFeNi intermetallic phases on the 1H18N9T steel and AlFeW on the SW18 steel. Regardless of the grade of testing steels there is Si element in all layers of the coat. There are morphological differences in tested layers. The second layer (AlFeW phase inside the coat on the SW18 steel consist of faced crystals growing into in outside silumin layer. On the 1H18N9T steel a boundary between transient and outside layer is more uniform. Free separations of intermetallic phases inside silumin layer on the 1H18N9T steel have lamellar and on the SW18 steel – faced form.

Quantitative analysis of silica aerogel-based thermal insulation coatings

DEFF Research Database (Denmark)

Kiil, Søren

2015-01-01

containing intact hollow glass or polymer spheres showed that silica aerogel particles are more efficient in an insulation coating than hollow spheres. In a practical (non-ideal) comparison, the ranking most likely cannot be generalized. A parameter study demonstrates how the model can be used, qualitatively......A mathematical heat transfer model for a silica aerogel-based thermal insulation coating was developed. The model can estimate the thermal conductivity of a two-component (binder-aerogel) coating with potential binder intrusion into the nano-porous aerogel structure. The latter is modelled using...... a so-called core–shell structure representation. Data from several previous experimental investigations with silica aerogels in various binder matrices were used for model validation. For some relevant cases with binder intrusion, it was possible to obtain a very good agreement between simulations...

Surface analysis of thin film coatings on container glass

Energy Technology Data Exchange (ETDEWEB)

Bhargava, A. [GCC Pty Ltd., Jindalee, QLD (Australia); Wood, B. [The University of Queensland, Brisbane, QLD (Australia). Department of Chemistry

1999-12-01

Full text: Container glass is generally coated with a tin oxide layer followed by a coating of polymer. These coatings are believed to improve the mechanical properties of container glass as well as aid in the application of advertising labels to glass. The tin oxide layer on commercial beer bottles has a total thickness of about 15-20nm which consists of an interfacial layer comprising 70-85% of the total thickness. The polymer coating is about 2-5nm thick and also possesses an interfacial layer with tin oxide. A PHI Model 560 XPS/ SAM/ SIMS multi-technique system Is used to estimate concentration profiles of Sn, O, C, Si, Ca, Na and O. A combination of XPS, AES and SIMS is necessary to describe the coatings. Instrumental conditions and sample preparation methods are developed to optimize the analysis of thin films on glass. The coating comprises of three areas, namely (A) where polymer and tin co-exist (B) a pure tin oxide layer and (C) where tin co-exists with glass. By varying the chemical source of tin, it is possible to systematically vary the thickness of the interface and the concentration profile of Sn. Using XRD, crystalline phase(s) could be detected in tin oxide films as thin as 15nm. While the principle phase is cassiterite, a second phase is also detected which is believed to originate from the interface. Using a UMIS 2000 nanoindentor system, instrumental parameters are optimized for measurement of elastic modulus of films at varying depths, i.e. from surface of coating to the bulk of the glass. A sharp rise is observed at depth corresponding to the interface which is indicative of the significance of the interfacial layer. Samples are prepared by systematic ion-milling which are representative of various regions of the coating, namely (A), (B) and (C). These samples are analyzed by XRD and TEM. Based on these studies, a structural model of tin oxide layer and interface is presented to explain increase in elastic modulus at the interface. Copyright

Surface analysis of thin film coatings on container glass

International Nuclear Information System (INIS)

Bhargava, A.; Wood, B.

1999-01-01

Full text: Container glass is generally coated with a tin oxide layer followed by a coating of polymer. These coatings are believed to improve the mechanical properties of container glass as well as aid in the application of advertising labels to glass. The tin oxide layer on commercial beer bottles has a total thickness of about 15-20nm which consists of an interfacial layer comprising 70-85% of the total thickness. The polymer coating is about 2-5nm thick and also possesses an interfacial layer with tin oxide. A PHI Model 560 XPS/ SAM/ SIMS multi-technique system Is used to estimate concentration profiles of Sn, O, C, Si, Ca, Na and O. A combination of XPS, AES and SIMS is necessary to describe the coatings. Instrumental conditions and sample preparation methods are developed to optimize the analysis of thin films on glass. The coating comprises of three areas, namely (A) where polymer and tin co-exist (B) a pure tin oxide layer and (C) where tin co-exists with glass. By varying the chemical source of tin, it is possible to systematically vary the thickness of the interface and the concentration profile of Sn. Using XRD, crystalline phase(s) could be detected in tin oxide films as thin as 15nm. While the principle phase is cassiterite, a second phase is also detected which is believed to originate from the interface. Using a UMIS 2000 nanoindentor system, instrumental parameters are optimized for measurement of elastic modulus of films at varying depths, i.e. from surface of coating to the bulk of the glass. A sharp rise is observed at depth corresponding to the interface which is indicative of the significance of the interfacial layer. Samples are prepared by systematic ion-milling which are representative of various regions of the coating, namely (A), (B) and (C). These samples are analyzed by XRD and TEM. Based on these studies, a structural model of tin oxide layer and interface is presented to explain increase in elastic modulus at the interface. Copyright

Investigation of the Influence of Ni Doping on the Structure and Hardness of Ti-Ni-C Coatings

Directory of Open Access Journals (Sweden)

J. Daniel

2017-01-01

Full Text Available Nanocomposite nc-TiC/a-C:H thin films exhibit unique combination of mechanical properties, high hardness, low friction, and wear. Selective doping by weak-carbide forming element can be used in order to specifically design the physical and chemical properties of nc-TiC/a-C:H coatings. In this paper we report on an effect of nickel addition on structure and hardness of the nc-TiC/a-C:H coatings. The effect of Ni alloying on the coating structure under conditions of DCMS and HiPIMS depositions was studied. The coating structure was correlated with the coating hardness. The grain size, the grain carbon vacancy concentration, and the mean grain separation were found to be the key parameters determining the coating hardness. Ni doping proved to have a significant effect on the coating microstructure which resulted in changes of the hardness of the deposited coatings.

Fabrication and excellent conductive performance of antimony-doped tin oxide-coated diatomite with porous structure

Energy Technology Data Exchange (ETDEWEB)

Du Yucheng, E-mail: ychengdu@bjut.edu.cn [Key Lab of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Yan Jing; Meng Qi; Wang Jinshu [Key Lab of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Dai Hongxing, E-mail: hxdai@bjut.edu.cn [Laboratory of Catalysis Chemistry and Nanoscience, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

2012-04-16

Graphical abstract: Antimony-doped tin oxide (ATO)-coated diatomite with porous structures are fabricated using the co-precipitation method. The porous ATO-coated diatomite material shows excellent conductive performance. Highlights: Black-Right-Pointing-Pointer Sb-doped SnO{sub 2} (ATO)-coated diatomite materials with porous structures are prepared. Black-Right-Pointing-Pointer Sn/Sb ratio, ATO coating amount, pH value, and temperature influence resistivity. Black-Right-Pointing-Pointer Porous ATO-coated diatomite materials show excellent conductive performance. Black-Right-Pointing-Pointer The lowest resistivity of the porous ATO-coated diatomite sample is 10 {Omega} cm. - Abstract: Diatomite materials coated with antimony-doped tin oxide (ATO) were prepared by the co-precipitation method, and characterized by means of the techniques, such as X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, selected-area electron diffraction, X-ray fluorescence spectroscopy, and N{sub 2} adsorption-desorption measurement. It was shown that the coated ATO possessed a tetragonal rutile crystal structure, and the ATO-coated diatomite materials had a multi-pore (micro- meso-, and macropores) architecture. The porous ATO-coated diatomite materials exhibited excellent electrical conductive behaviors. The best conductive performance (volume resistivity = 10 {Omega} cm) was achieved for the sample that was prepared under the conditions of Sn/Sb molar ratio = 5.2, Sn/Sb coating amount = 45 wt%, pH = 1.0, and reaction temperature = 50 Degree-Sign C. Such a conductive porous material is useful for the applications in physical and chemical fields.

Development of a hard nano-structured multi-component ceramic coating by laser cladding

International Nuclear Information System (INIS)

Masanta, Manoj; Ganesh, P.; Kaul, Rakesh; Nath, A.K.; Roy Choudhury, A.

2009-01-01

The present paper reports laser-assisted synthesis of a multi-component ceramic composite coating consisting of aluminum oxide, titanium di-boride and titanium carbide (Al 2 O 3 -TiB 2 -TiC). A pre-placed powder mixture of aluminum (Al), titanium oxide (TiO 2 ) and boron carbide (B 4 C) was made to undergo self-propagating high-temperature synthesis (SHS) by laser triggering. Laser subsequently effected cladding of the products of SHS on the substrate. The effect of laser scanning speed on the hardness, microstructure and phase composition of the composite coating was investigated. The coating exhibited an increase in hardness and a decrease in grain size with increase in laser scanning speed. A maximum micro-hardness of 2500 HV 0.025 was obtained. X-ray diffraction (XRD) of the top surface of the coating revealed the presence of aluminum oxide (Al 2 O 3 ), titanium di-boride (TiB 2 ) and titanium carbide (TiC) along with some non-stoichiometric products of the Ti-Al-B-C-O system. Field emission gun scanning electron microscopy (FESEM) and high-resolution transmission electron microscopic (HRTEM) analysis revealed some nano-structured TiB 2 and Al 2 O 3 , which are discussed in detail.

Structural ceramic coatings in composite microtruss cellular materials

Energy Technology Data Exchange (ETDEWEB)

Bele, E.; Bouwhuis, B.A.; Codd, C. [Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario (Canada); Hibbard, G.D., E-mail: glenn.hibbard@utoronto.ca [Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario (Canada)

2011-09-15

Graphical abstract: The compressive strength increase per unit sleeve thickness of Al cores reinforced with Al{sub 2}O{sub 3} sleeves is lower than the corresponding strength increase when the same cores are reinforced with nanocrystalline Ni (n-Ni) sleeves (left). However, because anodizing is a transformative surface treatment, the Al{sub 2}O{sub 3} coating was able to achieve this performance increase with little overall weight penalty (right). Display Omitted Highlights: {yields} A new type of metal/ceramic microtruss cellular composite has been created. {yields} Reinforcing sleeves of Al{sub 2}O{sub 3} were deposited on low density Al microtruss cores. {yields} Significant compressive strength increases were seen at virtually no weight penalty. {yields} Failure mechanisms were studied by electron microscopy and finite element analysis. {yields} Buckling, sleeve wrinkling, and coating fracture dictated the compressive strength. - Abstract: In the present study, anodizing was used to produce Al{sub 2}O{sub 3} coatings in a conventional 3003 aluminum alloy microtruss core; a 38.5 {mu}m thick anodic coating provided a 143% increase in compressive strength. Finite-element analyses were used to illustrate the dependence of the compressive strength and failure mechanism on the thickness of the anodic coating. At low thicknesses the microtruss strength is dictated by global bucking of the internal struts. However, at higher thicknesses the compressive strength is controlled by coating fracture and local deformation in the hinge region of the struts. Regardless of the failure mechanism, the compressive strength of the composite microtruss increased with increasing anodic coating thickness, with very little corresponding weight penalty.

In vitro analysis of biopolymer coating with glycidoxypropyltrimethoxysilane on hernia meshes.

Science.gov (United States)

Metzler, Steffen; Zankovych, Sergiy; Rauchfuß, Falk; Dittmar, Yves; Jandt, Karin; Jandt, Klaus D; Settmacher, Utz; Scheuerlein, Hubert

2017-07-01

Certain coatings may improve the biocompatibility of hernia meshes. The coating with self-assembled monolayers, such as glycidoxypropyltrimethoxysilane (GOPS) can also improve the materials characteristics of implants. This approach was not yet explored in hernia meshes. It was the aim of this work to clarify if and how hernia meshes with their three-dimensional structure can be coated with GOPS and with which technique this coating can be best characterized. Commercially available meshes made from polypropylene (PP), polyester (PE), and expanded polytetrafluorethylene (ePTFE) have been coated with GOPS. The coatings were analyzed via X-ray photoelectron spectroscopy (XPS), confocal laser scanning microscopy (CLSM), and cell proliferation test (mouse fibroblasts). Cell viability and cytotoxicity were tested by MTT test. With the GOPS surface modification, the adherence of mouse fibroblasts on polyester meshes and the proliferation on ePTFE meshes were increased compared to noncoated meshes. Both XPS and CLSM are limited in their applicability and validity due to the three-dimensional mesh structure while CLSM was overall more suitable. In the MTT test, no negative effects of the GOPS coating on the cells were detected after 24 h. The present results show that GOPS coating of hernia meshes is feasible and effective. GOPS coating can be achieved in a fast and cost-efficient way. Further investigations are necessary with respect to coating quality and adverse effects before such a coating may be used in the clinical routine. In conclusion, GOPS is a promising material that warrants further research as coating of medical implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1083-1090, 2017. © 2016 Wiley Periodicals, Inc.

Stress analysis of aspherical coated particle with inner pressure

Energy Technology Data Exchange (ETDEWEB)

Liu Bing, E-mail: bingliu@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Yang Lin; Liang Tongxiang; Tang Chunhe [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

2012-10-15

Coated particles used in HTR fuel element sustain the inner pressure during irradiation as a pressure vessel. In actually the coated particle is not real spherical but with some asphericity, the stress distribution in the vessel is not uniform, coated layer in aspherical particle sustain more additional stress due to the asphericity. In this paper, the geometric shape distribution is summarized based on actual coated particle statistic. A mechanical analysis model is proposed for SiC layer by geometric combinations, and stress distribution of coated particle with a flat is calculated. The results show that the local maximum stress of aspherical particle increased two times than that of ideal spherical coated particle, which increase the failure probability under irradiation and high temperature.

Crack monitoring method based on Cu coating sensor and electrical potential technique for metal structure

Directory of Open Access Journals (Sweden)

Hou Bo

2015-06-01

Full Text Available Advanced crack monitoring technique is the cornerstone of aircraft structural health monitoring. To achieve real-time crack monitoring of aircraft metal structures in the course of service, a new crack monitoring method is proposed based on Cu coating sensor and electrical potential difference principle. Firstly, insulation treatment process was used to prepare a dielectric layer on structural substrate, such as an anodizing layer on 2A12-T4 aluminum alloy substrate, and then a Cu coating crack monitoring sensor was deposited on the structure fatigue critical parts by pulsed bias arc ion plating technology. Secondly, the damage consistency of the Cu coating sensor and 2A12-T4 aluminum alloy substrate was investigated by static tensile experiment and fatigue test. The results show that strain values of the coating sensor and the 2A12-T4 aluminum alloy substrate measured by strain gauges are highly coincident in static tensile experiment and the sensor has excellent fatigue damage consistency with the substrate. Thirdly, the fatigue performance discrepancy between samples with the coating sensor and original samples was investigated. The result shows that there is no obvious negative influence on the fatigue performance of the 2A12-T4 aluminum alloy after preparing the Cu coating sensor on its surface. Finally, crack monitoring experiment was carried out with the Cu coating sensor. The experimental results indicate that the sensor is sensitive to crack, and crack origination and propagation can be monitored effectively through analyzing the change of electrical potential values of the coating sensor.

Micro/Nano Structural Tantalum Coating for Enhanced Osteogenic Differentiation of Human Bone Marrow Stem Cells.

Science.gov (United States)

Ding, Ding; Xie, Youtao; Li, Kai; Huang, Liping; Zheng, Xuebin

2018-04-03

Recently, tantalum has been attracting much attention for its anticorrosion resistance and biocompatibility, and it has been widely used in surface modification for implant applications. To improve its osteogenic differentiation of human bone marrow stem cells (hBMSCs), a micro/nano structure has been fabricated on the tantalum coating surface through the combination of anodic oxidation and plasma spraying method. The morphology, composition, and microstructure of the modified coating were comprehensively studied by employing scanning electron microscopy (SEM), X-ray diffraction (XRD) as well as transmission electron microscopy (TEM). The effects of hierarchical structures as well as micro-porous structure of tantalum coating on the behavior for human bone marrow stem cells (hBMSCs) were evaluated and compared at both cellular and molecular levels in vitro. The experimental results show that a hierarchical micro/nano structure with Ta₂O₅ nanotubes spread onto a micro-scale tantalum coating has been fabricated successfully, which is confirmed to promote cell adhesion and spreading. Besides, the hierarchical micro/nano tantalum coating can provide 1.5~2.1 times improvement in gene expression, compared with the micro-porous tantalum coating. It demonstrates that it can effectively enhance the proliferation and differentiation of hBMSCs in vitro.

Micro/Nano Structural Tantalum Coating for Enhanced Osteogenic Differentiation of Human Bone Marrow Stem Cells

Directory of Open Access Journals (Sweden)

Ding Ding

2018-04-01

Full Text Available Recently, tantalum has been attracting much attention for its anticorrosion resistance and biocompatibility, and it has been widely used in surface modification for implant applications. To improve its osteogenic differentiation of human bone marrow stem cells (hBMSCs, a micro/nano structure has been fabricated on the tantalum coating surface through the combination of anodic oxidation and plasma spraying method. The morphology, composition, and microstructure of the modified coating were comprehensively studied by employing scanning electron microscopy (SEM, X-ray diffraction (XRD as well as transmission electron microscopy (TEM. The effects of hierarchical structures as well as micro-porous structure of tantalum coating on the behavior for human bone marrow stem cells (hBMSCs were evaluated and compared at both cellular and molecular levels in vitro. The experimental results show that a hierarchical micro/nano structure with Ta2O5 nanotubes spread onto a micro-scale tantalum coating has been fabricated successfully, which is confirmed to promote cell adhesion and spreading. Besides, the hierarchical micro/nano tantalum coating can provide 1.5~2.1 times improvement in gene expression, compared with the micro-porous tantalum coating. It demonstrates that it can effectively enhance the proliferation and differentiation of hBMSCs in vitro.

Structure and properties of Hardox 450 steel with arc welded coatings

Science.gov (United States)

Ivanov, Yu. F.; Konovalov, S. V.; Kormyshev, V. E.; Gromov, V. E.; Teresov, A. D.; Semina, O. A.

2017-12-01

The paper reports on a study of the surface structure, phase composition, and microhardness of Hardox 450 steel with coatings deposited by arc welding of powder wires differing in chemical composition. The study shows that to a depth of 6-8 mm, the microhardness of the thus formed coatings is more than two times the microhardness of the base metal and that their higher mechanical properties are provided by martensite structure containing Nb2C and NbC carbides and Fe2B borides as eutectic lamellae with a transverse size of 30-70 nm; their volume reveals a net-like dislocation substructure with a scalar dislocation density of 1011 cm-2. The highest surface hardness is found for the steel coated with boron-containing wire material. Some ideas are suggested on possible mechanisms and temperature for the formation of Nb and B carbides during the process.

High temperature glass thermal control structure and coating. [for application to spacecraft reusable heat shielding

Science.gov (United States)

Stewart, D. A.; Goldstein, H. E.; Leiser, D. B. (Inventor)

1983-01-01

A high temperature stable and solar radiation stable thermal control coating is described which is useful either as such, applied directly to a member to be protected, or applied as a coating on a re-usable surface insulation (RSI). It has a base coat layer and an overlay glass layer. The base coat layer has a high emittance, and the overlay layer is formed from discrete, but sintered together glass particles to give the overlay layer a high scattering coefficient. The resulting two-layer space and thermal control coating has an absorptivity-to-emissivity ratio of less than or equal to 0.4 at room temperature, with an emittance of 0.8 at 1200 F. It is capable of exposure to either solar radiation or temperatures as high as 2000 F without significant degradation. When used as a coating on a silica substrate to give an RSI structure, the coatings of this invention show significantly less reduction in emittance after long term convective heating and less residual strain than prior art coatings for RSI structures.

Thermal Conductivity Analysis and Lifetime Testing of Suspension Plasma-Sprayed Thermal Barrier Coatings

Directory of Open Access Journals (Sweden)

Nicholas Curry

2014-08-01

Full Text Available Suspension plasma spraying (SPS has become an interesting method for the production of thermal barrier coatings for gas turbine components. The development of the SPS process has led to structures with segmented vertical cracks or column-like structures that can imitate strain-tolerant air plasma spraying (APS or electron beam physical vapor deposition (EB-PVD coatings. Additionally, SPS coatings can have lower thermal conductivity than EB-PVD coatings, while also being easier to produce. The combination of similar or improved properties with a potential for lower production costs makes SPS of great interest to the gas turbine industry. This study compares a number of SPS thermal barrier coatings (TBCs with vertical cracks or column-like structures with the reference of segmented APS coatings. The primary focus has been on lifetime testing of these new coating systems. Samples were tested in thermo-cyclic fatigue at temperatures of 1100 °C for 1 h cycles. Additional testing was performed to assess thermal shock performance and erosion resistance. Thermal conductivity was also assessed for samples in their as-sprayed state, and the microstructures were investigated using SEM.

Experimental Research on the Dynamic Response of Floating Structures with Coatings Subjected to Underwater Explosion

Directory of Open Access Journals (Sweden)

Feng Xiao

2014-01-01

Full Text Available This paper presents an experimental investigation into the dynamic response of three free floating stiffened metal boxes with protective coatings subjected to underwater explosion (UNDEX. One box was kept intact while the other two were, respectively, covered with monolithic coatings and chiral honeycomb coatings. Three groups of live fire tests with different attack angles and stand-off distances were conducted. The acceleration on the stiffener and strain peak on the bottom hull were selected as the major comparative criterions. Test results show that the impulse transmitted to the structure at the initial stage can be reduced, owing to the coating flexibility and fluid-structure interaction mechanism. Consequently, the acceleration peaks induced by both shock wave and bubble pulse were reduced. The shock environment can be more effectively improved by honeycomb coating when compared with monolithic coating. Most of the strain peaks decreased to a certain extent, but some of them were notably manifested, especially for honeycomb coating. The test affirms the fact that soft coating can cause stress concentration on the shell that is in direct contact with the coating due to the impedance mismatch between the interfaces of materials. A softer rubber coating induces a greater magnitude of strain.

Performance of a dual-process PVD/PS tungsten coating structure under deuterium ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyunmyung; Lee, Ho Jung; Kim, Sung Hwan [Department of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of); Song, Jae-Min [Department of Nuclear Engineering, Seoul National University, Seoul (Korea, Republic of); Jang, Changheui, E-mail: chjang@kaist.ac.kr [Department of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of)

2016-11-01

Highlights: • D{sup +} irradiation performance of a dual-process PVD/PS W coating was evaluated. • Low-energy plasmas exposure of 100 eV D{sup +} with 1.17 × 10{sup 21} D/s{sup −1} m{sup 2} flux was applied. • After D ion irradiation, flakes were observed on the surface of the simple PS coating. • While, sub-μm size protrusions were observed for dual-process PVD/PS W coating. • Height of D spike in depth profile was lower for dual-process PVD/PS W coating. - Abstract: A dual-process coating structure was developed on a graphite substrate to improve the performance of the coating structure under anticipated operating condition of fusion devices. A thin multilayer W/Mo coating (6 μm) was deposited by physical vapor deposition (PVD) method with a variation of Mo interlayer thickness on plasma spray (PS) W coating (160 μm) of a graphite substrate panel. The dual-process PVD/PS W coatings then were exposed to 3.08 × 10{sup 24} D m{sup −2} of 100 eV D ions with a flux of 1.71 × 10{sup 21} D m{sup −2} s{sup −1} in an electron cyclotron resonance (ECR) chamber. After irradiation, surface morphology and D depth profiles of the dual-process coating were analyzed and compared to those of the simple PS W coating. Both changes in surface morphology and D retention were strongly dependent on the microstructure of surface coating. Meanwhile, the existence of Mo interlayer seemed to have no significant effect on the retention of deuterium.

X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis

Science.gov (United States)

Roine, J.; Tenho, M.; Murtomaa, M.; Lehto, V.-P.; Kansanaho, R.

2007-10-01

The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers.

Structure and photoluminescence properties of Ag-coated ZnO nano-needles

Energy Technology Data Exchange (ETDEWEB)

Li Xiaozhu, E-mail: Lixiaozhu1019@21cn.com [Department of Physics, Shaoguan University, Shaoguan, Guangdong 512005 (China) and Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education, Wuhan University, Wuhan, Hubei 430072 (China); Wang Yongqian [Engineering Research Center of Nano-Geomaterials of Ministry of Education (China University of Geosciences), Wuhan, Hubei 430074 (China)

2011-05-12

Highlights: > ZnO nano-needles were synthesized by thermal oxidation. > Their surfaces were coated with Ag by pulse electro-deposition technique. > The uncoated and coated ZnO nano-needles were characterized. > The results showed that the prepared ZnO nano-needles have been coated with Ag successfully. > The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the Ag-coated ZnO nano-needles can increase the absorption of UV light. - Abstract: A large number of zinc oxide (ZnO) nano-needles were synthesized by thermal oxidation of pure zinc. The surfaces of ZnO nano-needles were coated with a layer of Ag by pulse electro-deposition technique. The uncoated and coated ZnO nano-needles were characterized by using the X-ray diffraction and the scanning electron microscope (SEM). The results showed that the uncoated samples were close-packed hexagonal structure, which showed needle-like morphology. Their average diameter is about 40 nm, lengths up to 5 {mu}m. At the same time we observed that the prepared ZnO nano-needles have been coated with Ag successfully. The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the uncoated ZnO nano-needles have two fluorescence peaks at 388 nm and 470.8 nm, respectively, the relative intensity of 143.4 and 93.61; and the Ag-coated ZnO nano-needles showed a pair of strong peaks at 387.4 nm and 405.2 nm, the relative intensity of 1366 and 1305, respectively, indicating that the Ag-coated ZnO nano-needles can increase the absorption of UV light.

Paint coating characterization for thermoelastic stress analysis of metallic materials

International Nuclear Information System (INIS)

Robinson, A F; Dulieu-Barton, J M; Quinn, S; Burguete, R L

2010-01-01

In thermoelastic stress analysis (TSA) it is normal practice to coat metallic specimens with black paint to enhance and standardize the surface emissivity. It is assumed that the paint coating has no effect on the thermal emission from the specimen, but it is well known that the response is sensitive to paint coating thickness, particularly at higher frequencies. In this paper the effects of loading frequency and paint coating thickness on the thermoelastic response are investigated. The thermoelastic response is compared to theory, and optimum test conditions and coating characteristics are suggested. The motivation for the work is to develop a TSA-based means of residual stress assessment, where the measurement of much smaller temperature changes than those that are resolved in standard TSA is required; therefore the analysis is much more sensitive to the effects of the paint coating. However, the work presented in this paper is relevant to a wide range of TSA investigations and presents data that will be of interest to all practitioners of TSA

Iridium Coating Deposited by Double Glow Plasma Technique — Effect of Glow Plasma on Structure of Coating at Single Substrate Edge

International Nuclear Information System (INIS)

Wu Wangping; Chen Zhaofeng; Liu Yong

2012-01-01

Double glow plasma technique has a high deposition rate for preparing iridium coating. However, the glow plasma can influence the structure of the coating at the single substrate edge. In this study, the iridium coating was prepared by double glow plasma on the surface of single niobium substrate. The microstructure of iridium coating at the substrate edge was observed by scanning electron microscopy. The composition of the coating was confirmed by energy dispersive spectroscopy and X-ray diffraction. There was a boundary between the coating and the substrate edge. The covered area for the iridium coating at the substrate edge became fewer and fewer from the inner area to the outer flange-area. The bamboo sprout-like particles on the surface of the substrate edge were composed of elemental niobium. The substrate edge was composed of the Nb coating and there was a transition zone between the Ir coating and the Nb coating. The interesting phenomenon of the substrate edge could be attributed to the effects of the bias voltages and the plasma cloud in the deposition chamber. The substrate edge effect could be mitigated or eliminated by adding lots of small niobium plates around the substrate in a deposition process. (plasma technology)

Development of a hard nano-structured multi-component ceramic coating by laser cladding

Energy Technology Data Exchange (ETDEWEB)

Masanta, Manoj [Department of Mechanical Engineering, IIT Kharagpur, West Bengal 721302 (India); Ganesh, P.; Kaul, Rakesh [Laser Material Processing Division, Raja Ramanna Centre for Advanced Technology, Indore (India); Nath, A.K. [Department of Mechanical Engineering, IIT Kharagpur, West Bengal 721302 (India); Roy Choudhury, A., E-mail: roychoudhuryasimava@gmail.com [Department of Mechanical Engineering, IIT Kharagpur, West Bengal 721302 (India)

2009-05-20

The present paper reports laser-assisted synthesis of a multi-component ceramic composite coating consisting of aluminum oxide, titanium di-boride and titanium carbide (Al{sub 2}O{sub 3}-TiB{sub 2}-TiC). A pre-placed powder mixture of aluminum (Al), titanium oxide (TiO{sub 2}) and boron carbide (B{sub 4}C) was made to undergo self-propagating high-temperature synthesis (SHS) by laser triggering. Laser subsequently effected cladding of the products of SHS on the substrate. The effect of laser scanning speed on the hardness, microstructure and phase composition of the composite coating was investigated. The coating exhibited an increase in hardness and a decrease in grain size with increase in laser scanning speed. A maximum micro-hardness of 2500 HV{sub 0.025} was obtained. X-ray diffraction (XRD) of the top surface of the coating revealed the presence of aluminum oxide (Al{sub 2}O{sub 3}), titanium di-boride (TiB{sub 2}) and titanium carbide (TiC) along with some non-stoichiometric products of the Ti-Al-B-C-O system. Field emission gun scanning electron microscopy (FESEM) and high-resolution transmission electron microscopic (HRTEM) analysis revealed some nano-structured TiB{sub 2} and Al{sub 2}O{sub 3}, which are discussed in detail.

Core/Shell Structure of TiO2-Coated MWCNTs for Thermal Protection for High-Temperature Processing of Metal Matrix Composites

Directory of Open Access Journals (Sweden)

Laura Angélica Ardila Rodriguez

2018-01-01

Full Text Available The production of metal matrix composites with elevated mechanical properties depends largely on the reinforcing phase properties. Due to the poor oxidation resistance of multiwalled carbon nanotubes (MWCNTs as well as their high reactivity with molten metal, the processing conditions for the production of MWCNT-reinforced metal matrix composites may be an obstacle to their successful use as reinforcement. Coating MWCNTs with a ceramic material that acts as a thermal protection would be an alternative to improve oxidation stability. In this work, MWCNTs previously functionalized were coated with titanium dioxide (TiO2 layers of different thicknesses, producing a core-shell structure. Heat treatments at three different temperatures (500°C, 750°C, and 1000°C were performed on coated nanotubes in order to form a stable metal oxide structure. The MWCNT/TiO2 hybrids produced were evaluated in terms of thermal stability. Thermogravimetric analysis (TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy (RS, and X-ray photoelectron spectroscopy (XPS were performed in order to investigate TiO2-coated MWCNT structure and thermal stability under oxidative atmosphere. It was found that the thermal stability of the TiO2-coated MWCNTs was dependent of the TiO2 layer morphology that in turn depends on the heat treatment temperature.

Tool life of the edges coated with the c-BN+h-BN coatings with different structures during hard machinable steel machining

Directory of Open Access Journals (Sweden)

Kupczyk, M.

2005-12-01

Full Text Available In the presented paper the experimental results concerning the functional quality (durability during steel machining of thin, superhard coatings produced on the cutting edges are described. Differences among mentioned properties of coatings mainly result from a coating structure. But the structure of coatings results from deposition parameters Superhard boron nitride coatings were deposited on insert cutting edges made of cemented carbides by the pulse-plasma method applying different values of the discharge voltage. The comparative investigations of mentioned coatings have been concerned of tool life of edges during hard machinable material machining (nitriding steel hardened in oil. In these investigations for the purpose of additional increase of coatings adhesion to substrates an interfacial layers were applied.

En este trabajo se describen los resultados experimentales referentes a la calidad funcional (durabilidad durante el mecanizado del acero de recubrimientos delgados, de elevada dureza del filo de corte. Las diferencias en las propiedades de los recubrimientos se deben, principalmente, a la estructura del recubrimiento. No obstante, la estructura del recubrimiento está relacionada con los parámetros de la deposición. Recubrimientos de nitruro de boro de elevada dureza se depositaron sobre filos de corte insertados, fabricados con carburos cementados mediante el método de pulsos de plasma aplicando diferentes valores de voltaje de descarga. Las investigaciones comparativas de los mencionados recubrimientos han relacionado la vida del filo de la herramienta durante el mecanizado del material (acero nitrurado endurecido en aceite. En estas investigaciones se aplicaron capas interfaciales para aumentar la adherencia del recubrimiento.

Structure And Properties Of PVD Coatings Deposited On Cermets

Directory of Open Access Journals (Sweden)

Żukowska L.

2015-06-01

Full Text Available The main aim of the research is the investigation of the structure and properties of single-layer and gradient coatings of the type (Ti,AlN and Ti(C,N deposited by physical vapour deposition technology (PVD on the cermets substrate.

PIT Coating Requirements Analysis

International Nuclear Information System (INIS)

MINTEER, D.J.

2000-01-01

This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products

PIT Coating Requirements Analysis

Energy Technology Data Exchange (ETDEWEB)

MINTEER, D.J.

2000-10-20

This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

Structure and photoluminescence properties of Ag-coated ZnO nano-needles

International Nuclear Information System (INIS)

Li Xiaozhu; Wang Yongqian

2011-01-01

Highlights: → ZnO nano-needles were synthesized by thermal oxidation. → Their surfaces were coated with Ag by pulse electro-deposition technique. → The uncoated and coated ZnO nano-needles were characterized. → The results showed that the prepared ZnO nano-needles have been coated with Ag successfully. → The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the Ag-coated ZnO nano-needles can increase the absorption of UV light. - Abstract: A large number of zinc oxide (ZnO) nano-needles were synthesized by thermal oxidation of pure zinc. The surfaces of ZnO nano-needles were coated with a layer of Ag by pulse electro-deposition technique. The uncoated and coated ZnO nano-needles were characterized by using the X-ray diffraction and the scanning electron microscope (SEM). The results showed that the uncoated samples were close-packed hexagonal structure, which showed needle-like morphology. Their average diameter is about 40 nm, lengths up to 5 μm. At the same time we observed that the prepared ZnO nano-needles have been coated with Ag successfully. The photoluminescence spectrums of ZnO nano-needles with Ag-coated and uncoated were analyzed, finding that the uncoated ZnO nano-needles have two fluorescence peaks at 388 nm and 470.8 nm, respectively, the relative intensity of 143.4 and 93.61; and the Ag-coated ZnO nano-needles showed a pair of strong peaks at 387.4 nm and 405.2 nm, the relative intensity of 1366 and 1305, respectively, indicating that the Ag-coated ZnO nano-needles can increase the absorption of UV light.

Fracture toughness of esthetic dental coating systems by nanoindentation and FIB sectional analysis.

Science.gov (United States)

Pecnik, Christina Martina; Courty, Diana; Muff, Daniel; Spolenak, Ralph

2015-07-01

Improving the esthetics of Ti-based dental implants is the last challenge remaining in the optimization process. The optical issues were recently solved by the application of highly and selectively reflective coatings on Ti implants. This work focuses on the mechanical durability of these esthetic ceramic based coating systems (with and without adhesion layers). The coating systems (Ti-ZrO2, Ti-Al-ZrO2, Ti-Ti-Al-ZrO2, Ti-Ag-ZrO2, Ti-Ti-Ag-ZrO2, Ti-Bragg and Ti-TiO2-Bragg) were subjected to nanoindentation experiments and examined using scanning electron microscopy and focused ion beam cross sectional analysis. Three coating systems contained adhesion layers (10nm of Ti or 60nm of TiO2 layers). The fracture toughness of selected samples was assessed applying two different models from literature, a classical for bulk materials and an energy-based model, which was further developed and adjusted. The ZrO2 based coating systems (total film thickness<200nm) followed a circumferential cracking behavior in contrast to Bragg coated samples (total film thickness around 1.5μm), which showed radial cracking emanating from the indent corners. For Ti-ZrO2 samples, a fracture toughness between 2.70 and 3.70MPam(1/2) was calculated using an energy-based model. The classical model was applied to Bragg coated samples and their fracture toughness ranged between 0.70 and 0.80MPam(1/2). Furthermore, coating systems containing an additional layer (Ti-Ti-Al-ZrO2, Ti-Ti-Ag-ZrO2 and Ti-TiO2-Bragg) showed an improved adhesion between the substrate and the coating. The addition of a Ti or TiO2 layer improved the adhesion between substrate and coating. The validity of the models for the assessment of the fracture toughness depended on the layer structure and fracture profile of the samples investigated here (classical model for thick coatings and energy-based model for thin coatings). Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of weathering on performance of intumescent coatings for structure fire protection in the wildland-urban interface

Science.gov (United States)

Bahrani, Babak

The objective of this study was to investigate the effects of weathering on the performance of intumescent fire-retardant coatings on wooden products. The weathering effects included primary (solar irradiation, moisture, and temperature) and secondary (environmental contaminants) parameters at various time intervals. Wildland urban interface (WUI) fires have been an increasing threat to lives and properties. Existing solutions to mitigate the damages caused by WUI fires include protecting the structures from ignition and minimizing the fire spread from one structure to another. These solutions can be divided into two general categories: active fire protection systems and passive fire protection systems. Passive systems are either using pre-applied wetting agents (water, gel, or foam) or adding an extra layer (composite wraps or coatings). Fire-retardant coating treatment methods can be divided into impregnated (penetrant) and intumescent categories. Intumescent coatings are easy to apply, economical, and have a better appearance in comparison to other passive fire protection methods, and are the main focus of this study. There have been limited studies conducted on the application of intumescent coatings on wooden structures and their performance after long-term weathering exposure. The main concerns of weathering effects are: 1) the reduction of ignition resistance of the coating layer after weathering; and 2) the fire properties of coatings after weathering since coatings might contribute as a combustible fuel and assist the fire growth after ignition. Three intumescent coatings were selected and exposed to natural weathering conditions in three different time intervals. Two types of tests were performed on the specimens: a combustibility test consisted of a bench-scale performance evaluation using a Cone Calorimeter, and a thermal decomposition test using Simultaneous Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) method (also known

Exploring Polymer-Modified Concrete and Cementitious Coating with High-Durability for Roadside Structures in Xinjiang, China

Directory of Open Access Journals (Sweden)

Yinchuan Guo

2017-01-01

Full Text Available The concrete roadside structures in Xinjiang, China, such as roadside barriers, bridge rails, and drainage holes, are severely damaged by the coupled effect of seasonal freeze-thaw cycles and deicer salts. To solve the corrosion problems of roadside structures, polymer-modified concrete was recommended for the future construction of roadside structures and polymer-modified cementitious coating was suggested for the protection of the current corroded ones. In this study, air-entraining agent and carboxylated styrene-butadiene latex were added for concrete modification and the corresponding performance tests were conducted. In addition, the performances of six types of readily available coating materials, including the acrylic latex modified cementitious coating designed in this study, were tested in freeze-thaw condition with the presence of chloride ions. The results show that 0.013% of the air-entraining agent and 10% of the carboxylated styrene-butadiene latex were appropriate dosage rates for the modification of Portland cement concrete, in terms of the improvement of the freeze-thaw resistance, compressive strength, and chloride impermeability. For the protection of the current corroded roadside structures, the acrylic-modified cementitious coating material demonstrated a good performance and the field monitoring confirmed that the coating is suitable for the protection of the roadside structures in Xinjiang.

Identification and Structural Characterization of Unidentified Impurity in Bisoprolol Film-Coated Tablets

Directory of Open Access Journals (Sweden)

Ivana Mitrevska

2017-01-01

Full Text Available The aim of this study is the identification, structural characterization, and qualification of a degradation impurity of bisoprolol labeled as Impurity RRT 0.95. This degradation product is considered as a principal thermal degradation impurity identified in bisoprolol film-coated tablets. The impurity has been observed in the stress thermal degradation study of the drug product. Using HPLC/DAD/ESI-MS method, a tentative structure was assigned and afterwards confirmed by detailed structural characterization using NMR spectroscopy. The structure of the target Impurity RRT 0.95 was elucidated as phosphomonoester of bisoprolol, having relative molecular mass of 406 (positive ionization mode. The structural characterization was followed by qualification of Impurity RRT 0.95 using several different in silico methodologies. From the results obtained, it can be concluded that no new structural alerts have been generated for Impurity RRT 0.95 relative to the parent compound bisoprolol. The current study presents an in-depth analysis of the full characterization and qualification of an unidentified impurity in a drug product with the purpose of properly defining the quality specification of the product.

Analysis of polypyrrole-coated stainless steel electrodes

Indian Academy of Sciences (India)

Analysis of polypyrrole-coated stainless steel electrodes - Estimation of specific ... is carried out on stainless steel electrodes using -toluene sulphonic acid. ... The feasibility of the electrode for supercapacitor applications is investigated.

Structural characterisation of oxygen diffusion hardened alpha-tantalum PVD-coatings on titanium.

Science.gov (United States)

Hertl, C; Koll, L; Schmitz, T; Werner, E; Gbureck, U

2014-08-01

Titanium substrates were coated with tantalum layers of 5 μm thickness using physical vapour deposition (PVD). The tantalum layers showed a (110)-preferred orientation. The coated samples were hardened by oxygen diffusion. Using X-ray diffraction the crystallographic structure of the tantalum coatings was characterised, comparing untreated and diffusion hardened specimen conditions. Oxygen depth profiles were determined by glow discharge spectrometry. The hardening effect of the heat treatment was examined by Vickers microhardness testing. The increase of surface hardness caused by oxygen diffusion was at least 50%. Copyright © 2014 Elsevier B.V. All rights reserved.

Structure and properties of composite iron-based coatings obtained by the electromechanical technique

Science.gov (United States)

Dubinskii, N. A.

2007-09-01

The influence of the electrolyte temperature and current density on the content of inclusions of powder particles in composite coatings obtained by the electrochemical technique has been investigated. It has been found that the wear resistance of iron coatings with inclusions of powder particles of aluminum, kaolin, and calcium silicate increases from 5 to 10 times compared to coating without inclusions of disperse particles, and the friction coefficient therewith decreases from 0.097 to 0.026. It has been shown that the mechanical properties of iron obtained by the method of electrochemical deposition depend on their fine structure. The regimes of deposition of iron-based coatings have been optimized.

Suppressing Structural Colors of Photocatalytic Optical Coatings on Glass: The Critical Role of SiO2.

Science.gov (United States)

Li, Ronghua; Boudot, Mickael; Boissière, Cédric; Grosso, David; Faustini, Marco

2017-04-26

The appearance of structural colors on coated-glass is a critical esthetical drawback toward industrialization of photocatalytic coatings on windows for architecture or automobile. Herein we describe a rational approach to suppress the structural color of mesoporous TiO 2 -based coatings preserving photoactivity and mechanical stiffness. Addition of SiO 2 as third component is discussed. Ti x Si (1-x) O 2 mesoporous coatings were fabricated by one-step liquid deposition process through the evaporation induced self-assembling and characterized by GI-SAXS, GI-WAXS, electron microscopies, and in situ Environmental Ellipsometry Porosimetry. Guided by optical simulation, we investigated the critical role of SiO 2 on the optical responses of the films but also on the structural, mechanical, and photocatalytic properties, important requirements to go toward real applications. We demonstrate that adding SiO 2 to porous TiO 2 allows tuning and suppression of structural colors through refractive index matching and up to 160% increase in mechanical stiffening of the films. This study leads us to demonstrate an example of "invisible" coating, in which the light reflection is angle- and thickness-independent, and exhibiting high porosity, mechanical stiffness, and photoactivity.

Application of X-ray micro-CT for micro-structural characterization of APCVD deposited SiC coatings on graphite conduit.

Science.gov (United States)

Agrawal, A K; Sarkar, P S; Singh, B; Kashyap, Y S; Rao, P T; Sinha, A

2016-02-01

SiC coatings are commonly used as oxidation protective materials in high-temperature applications. The operational performance of the coating depends on its microstructure and uniformity. This study explores the feasibility of applying tabletop X-ray micro-CT for the micro-structural characterization of SiC coating. The coating is deposited over the internal surface of pipe structured graphite fuel tube, which is a prototype of potential components of compact high-temperature reactor (CHTR). The coating is deposited using atmospheric pressure chemical vapor deposition (APCVD) and properties such as morphology, porosity, thickness variation are evaluated. Micro-structural differences in the coating caused by substrate distance from precursor inlet in a CVD reactor are also studied. The study finds micro-CT a potential tool for characterization of SiC coating during its future course of engineering. We show that depletion of reactants at larger distances causes development of larger pores in the coating, which affects its morphology, density and thickness. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation on cored-eutectic structure in Ni60/WC composite coatings fabricated by wide-band laser cladding

Energy Technology Data Exchange (ETDEWEB)

Ma, Qunshuang, E-mail: maqunshuang@126.com; Li, Yajiang, E-mail: yajli@sdu.edu.cn; Wang, Juan, E-mail: jwang@sdu.edu.cn; Liu, Kun, E-mail: liu_kun@163.com

2015-10-05

Highlights: • Perfect composite coatings were fabricated using wide-band laser cladding. • Special cored-eutectic structure was synthesized in Ni60/WC composite coatings. • Cored-eutectic consists of hard carbide compounds and fine lamellar eutectic of M{sub 23}C{sub 6} carbides and γ-Ni(Fe). • Wear resistance of coating layer was significantly improved due to precipitation of M{sub 23}C{sub 6} carbides. - Abstract: Ni60 composite coatings reinforced with WC particles were fabricated on the surface of Q550 steel using LDF4000-100 fiber laser device. The wide-band laser and circular beam laser used in laser cladding were obtained by optical lens. Microstructure, elemental distribution, phase constitution and wear properties of different composite coatings were investigated. The results showed that WC particles were partly dissolved under the effect of wide-band fiber laser irradiation. A special cored-eutectic structure was synthesized due to dissolution of WC particles. According to EDS and XRD results, the inside cores were confirmed as carbides of M{sub 23}C{sub 6} enriched in Cr, W and Fe. These complex carbides were primarily separated out in the molten metal when solidification started. Eutectic structure composed of M{sub 23}C{sub 6} carbides and γ-Ni(Fe) grew around carbides when cooling. Element content of Cr and W is lower at the bottom of cladding layer. In consequence, the eutectic structure formed in this region did not have inside carbides. The coatings made by circular laser beam were composed of dendritic matrix and interdendritic eutectic carbides, lacking of block carbides. Compared to coatings made by circular laser spot, the cored-eutectic structure formed in wide-band coatings had advantages of well-distribution and tight binding with matrix. The uniform power density and energy distribution and the weak liquid convection in molten pool lead to the unique microstructure evolution in composite coatings made by wide-band laser

THE STRUCTURE AND MECHANICAL PROPERTIES OF NiCrBSi COATINGS PREPARED BY LASER BEAM CLADDING

Directory of Open Access Journals (Sweden)

Zita Iždinská

2010-03-01

Full Text Available In this work, the influence of processing conditions on the microstructure and abrasive wear behavior of a NiCrBSi laser clad coating is analyzed. The powder was applied onto a mild steel substrate (Fe–0.17% C by different laser powers and cladding speeds providing 0.7 – 1.2 mm thick coatings. The microstructure of coatings was analyzed by scanning electron microscopy (SEM. Energy-dispersive X-ray spectroscopy (EDX was applied for chemical analysis and tribological properties of coatings were evaluated by pin-on-disc wear test. EDX analysis reveals the influence of cladding speed on dilution of iron from the substrate into the coating. Higher iron content matches with lower hardness and wear resistance of appropriate coatings. Obtained results indicate that laser cladding is suitable technique for manufacturing NiCrBSi abrasive wear coatings and that it is possible to find out proper parameters in order to optimize tribological behavior of these coatings.

Formation and properties of chromium nitride coatings on martensitic steels

International Nuclear Information System (INIS)

Mendala, B.; Swadzba, L.; Hetmanczyk, M.

1999-01-01

In this paper the results of investigation of coatings obtained by ARC-PVD method on martensitic E1961 (13H12NWMFA) steel, which is used on compressor blades in the aircraft engines, were presented. The chemical composition of E1961 was given. The PVT-550 device was used for coating. The protective chromium nitride coatings were tested. The influence of ARC-PVD method parameters for example: bias, pressure and flow rate of reactive gases on the structure and properties of the CrN coatings in corrosion tests were investigated. Technical parameters of obtained CrN coatings were given. The phase analysis of chromium nitride coatings obtained with different technical parameters were tested. The results of phase analysis are given. The pitting corrosion resistance tests in 10% FeCl 3 solution was conducted. The corrosion rate for CrN coated samples were defined. It was found that 50 V and 100 V bias, about 0.5 and 0.7 Pa pressure and 140 sccm (standard cubic centimeter) flow rate of nitride during coating favour the CrN monophase structure while increasing bias to 150 V, decreasing the pressure to about 0.5 Pa and 0.3 Pa and increasing the flow rate of nitride to 160 - 180 sccm favour the CrN+Cr 2 N diphase structure. On the basis of corrosion investigations for CrN coatings obtained with different ARC-PVD parameters the best corrosion resistance in 10% FeCl 3 solution for CrN+Cr 2 N diphase structure was found. (author)

Control over Coating Structure during Electromagnetic Welding and Application of HighSpeed Steel Powder

Directory of Open Access Journals (Sweden)

L. M. Kozhuro

2004-01-01

Full Text Available The paper considers peculiar features concerning coating formation in the process of electromagnetic welding of high-speed steel powder. The paper reveals how to control coating structure that ensures the required operational properties of working surfaces of machine parts. 

Thermal analysis of the effect of thick thermal barrier coatings on diesel engine performance

International Nuclear Information System (INIS)

Hoag, K.L.; Frisch, S.R.; Yonushonis, T.M.

1986-01-01

The reduction of heat rejection from the diesel engine combustion chamber has been the subject of a great deal of focus in recent years. In the pursuit of this goal, Cummins Engine Company has received a contract from the Department of Energy for the development of thick thermal barrier coatings for combustion chamber surfaces. This contract involves the analysis of the impact of coatings on diesel engine performance, bench test evaluation of various coating designs, and single cylinder engine tests. The efforts reported in this paper center on the analysis of the effects of coatings on engine performance and heat rejection. For this analysis the conventional water cooled engine was compared with an engine having limited oil cooling, and utilizing zirocnia coated cylinder had firedecks and piston crowns. The analysis showed little or no benefits of similarly coating the valves or cylinder liner

Structure-function relationship of viral coat proteins : a site-directed spectroscopic study of M13 coat protein

NARCIS (Netherlands)

Stopar, D.

1997-01-01

This thesis describes the results of a spectroscopic study of the major coat protein of bacteriophage M13. During the infection process this protein is incorporated into the cytoplasmic membrane of Escherichia coli host cells. To specifically monitor the local structural changes

Ion assisted deposition of refractory oxide thin film coatings for improved optical and structural properties

International Nuclear Information System (INIS)

Sahoo, N.K.; Thakur, S.; Bhattacharyya, D.; Das, N.C.

1999-03-01

Ion assisted deposition technique (IAD) has emerged as a powerful tool to control the optical and structural properties of thin film coatings. Keeping in view the complexity of the interaction of ions with the films being deposited, sophisticated ion sources have been developed that cater to the need of modern optical coatings with stringent spectral and environmental specifications. In the present work, the results of ion assisted deposition (IAD) of two commonly used refractory oxides, namely TiO 2 and ZrO 2 , using cold cathode ion source (CC-102R) are presented. Through successive feedback and calibration techniques, various ion beams as well as deposition parameters have been optimized to achieve the best optical and structural film properties in the prevalent deposition geometry of the coating system. It has been possible to eliminate the unwanted optical and structural inhomogeneities from these films using and optimized set of process parameters. Interference modulated spectrophotometric and phase modulated ellipsometric techniques have been very successfully utilized to analyze the optical and structural parameters of the films. Several precision multilayer coatings have been developed and are being used for laser and spectroscopic applications. (author)

Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate.

Science.gov (United States)

Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun

2013-05-01

Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate.

Structure and properties of combined coatings on C (graphite)/Al/Al2O3 base after Ti ion implantation with subsequent electron beam irradiation

International Nuclear Information System (INIS)

Pogrebnjak, A.D.; Pogrebnjak, N.A.; Gritsenko, B.P.; Kylyshkanov, M.K.; Ruzimov, Sh.M.

2004-01-01

Full text: The presented report deals with new results on deposition of combined coatings using Al metallization (by a plasma jet) and micro-arc (discharge) Al oxidation. After this, the coating was implanted by Ti ions with 5·10 I7 cm -2 dose (60 and 90 kV and about 200 μs duration). One series of samples with such coatings was irradiated using the accelerator Y-112 by an electron beam in melting regime (two regimes). Analysis of the structure and element composition was performed using SIMS, RBS, SEM with micro-analysis (WDS), XRD as well as measurements of microhardness, wear and adhesion. It had been demonstrated that the coating was able to sustain very high temperatures and oxidation medium. However, after electron beam irradiation temperature resistance decreased because the oxide coating was melted almost to the graphite surface. The work was funded by the Project of NANU 'Nanosystems, nanomaterials and nanotechnology'

A combined histology and transcriptome analysis unravels novel questions on Medicago truncatula seed coat

Science.gov (United States)

Abirached-Darmency, Mona

2013-01-01

The seed coat is involved in the determination of seed quality traits such as seed size, seed composition, seed permeability, and hormonal regulation. Understanding seed coat structure is therefore a prerequisite to deciphering the genetic mechanisms that govern seed coat functions. By combining histological and transcriptomic data analyses, cellular and molecular events occurring during Medicago truncatula seed coat development were dissected in order to relate structure to function and pinpoint target genes potentially involved in seed coat traits controlling final seed quality traits. The analyses revealed the complexity of the seed coat transcriptome, which contains >30 000 genes. In parallel, a set of genes showing a preferential expression in seed coat that may be involved in more specific functions was identified. The study describes how seed coat anatomy and morphological changes affect final seed quality such as seed size, seed composition, seed permeability, and hormonal regulation. Putative regulator genes of different processes have been identified as potential candidates for further functional genomic studies to improve agronomical seed traits. The study also raises new questions concerning the implication of seed coat endopolyploidy in cell expansion and the participation of the seed coat in de novo abscisic acid biosynthesis at early seed filling. PMID:23125357

Demonstration of Thermally Sprayed Metal and Polymer Coatings for Steel Structures at Fort Bragg, NC

Science.gov (United States)

2017-09-01

ER D C/ CE RL T R- 17 -3 0 DoD Corrosion Prevention and Control Program Demonstration of Thermally Sprayed Metal and Polymer Coatings...and Polymer Coatings for Steel Structures at Fort Bragg, NC Final Report on Project F07-AR10 Larry D. Stephenson, Alfred D. Beitelman, Richard G...5 2.1.2 Thermoplastic polymer coating (flame spray

Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

Science.gov (United States)

Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław; Brytan, Zbigniew

2016-12-01

The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were recorded during the modelling process.

High performance sandwich structured Si thin film anodes with LiPON coating

Science.gov (United States)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-04-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solidelectrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Formation of SiO2/polytetrafluoroethylene hybrid superhydrophobic coating

International Nuclear Information System (INIS)

Zheng Yansheng; He Yi; Qing Yongquan; Zhuo Zhihao; Mo Qian

2012-01-01

Highlights: ► The coating showed the water contact angle of 165° and the water sliding angle of 6°. ► The hierarchical structure with the low surface energy leads to surface superhydrophobicity. ► We demonstrated a simple yet efficient approach to preparing superhydrophobic surface. - Abstract: Superhydrophobic coating has been fabricated on the glass substrates with modified SiO 2 sol and polytetrafluoroethylene emulsion through a sol–gel process. SiO 2 sol was modified with γ-glycidoxypropyl trimethoxysilane. The coatings were characterized by water contact angle measurement, Scanning electron microscope, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy and thermal synthetic analysis. The experimental results show that coatings exhibited superhydrophobic and heat-resistant property with a water average contact angle of 156° and sliding angle of 6°, coating has a rough surface with both micro- and nanoscale structures, γ-glycidoxypropyl trimethoxysilane enhanced the hydrophobicity of the coatings. Low surface energy of polymer and special structure of the coatings were responsible for the hydrophobic of the surfaces.

Adhesive Strength of dry Adhesive Structures Depending on the Thickness of Metal Coating

International Nuclear Information System (INIS)

Kim, Gyu Hye; Kwon, Da Som; Kim, Mi Jung; Kim, Su Hee; Yoon, Ji Won; An, Tea Chang; Hwang, Hui Yun

2016-01-01

Recently, engineering applications have started to adopt solutions inspired by nature. The peculiar adhesive properties of gecko skin are an example, as they allow the animal to move freely on vertical walls and even on ceilings. The high adhesive forces between gecko feet and walls are due to the hierarchical microscopical structure of the skin. In this study, the effect of metal coatings on the adhesive strength of synthetic, hierarchically structured, dry adhesives was investigated. Synthetic dry adhesives were fabricated using PDMS micro-molds prepared by photolithography. Metal coatings on synthetic dry adhesives were formed by plasma sputtering. Adhesive strength was measured by pure shear tests. The highest adhesion strengths were found with coatings composed of 4 nm thick layers of Indium, 8 nm thick layers of Zinc and 6 nm thick layers of Gold, respectively

Adhesive Strength of dry Adhesive Structures Depending on the Thickness of Metal Coating

Energy Technology Data Exchange (ETDEWEB)

Kim, Gyu Hye; Kwon, Da Som; Kim, Mi Jung; Kim, Su Hee; Yoon, Ji Won; An, Tea Chang; Hwang, Hui Yun [Andong National Univ., Andong (Korea, Republic of)

2016-07-15

Recently, engineering applications have started to adopt solutions inspired by nature. The peculiar adhesive properties of gecko skin are an example, as they allow the animal to move freely on vertical walls and even on ceilings. The high adhesive forces between gecko feet and walls are due to the hierarchical microscopical structure of the skin. In this study, the effect of metal coatings on the adhesive strength of synthetic, hierarchically structured, dry adhesives was investigated. Synthetic dry adhesives were fabricated using PDMS micro-molds prepared by photolithography. Metal coatings on synthetic dry adhesives were formed by plasma sputtering. Adhesive strength was measured by pure shear tests. The highest adhesion strengths were found with coatings composed of 4 nm thick layers of Indium, 8 nm thick layers of Zinc and 6 nm thick layers of Gold, respectively.

Phase transformations of nanostructured Zr-Y-O coatings under loading

Science.gov (United States)

Fedorischeva, M. V.; Kalashnikov, M. P.; Bozhko, I. A.; Mironov, Yu. P.; Sergeev, V. P.

2017-12-01

The deposition of nanostructured Zr-Y-O/Si-Al-N-based coatings was implemented by the pulse magnetron methods. The structural-phase state of the nanostructured coatings was studied with TEM and X-ray analysis. The phase transformation in Zr-Y-O layer was observed with the X-ray diffraction analysis in the "in-situ" mode under loading in conditions of free and constrained volumes. It was found, that there were martensitic phase transformations at certain deformation levels under the conditions of the free volume and martensitic phase transformations in the local regions of the coating layer with the structure fining in constrained volume.

Quantitation of Surface Coating on Nanoparticles Using Thermogravimetric Analysis.

Science.gov (United States)

Dongargaonkar, Alpana A; Clogston, Jeffrey D

2018-01-01

Nanoparticles are critical components in nanomedicine and nanotherapeutic applications. Some nanoparticles, such as metallic nanoparticles, consist of a surface coating or surface modification to aid in its dispersion and stability. This surface coating may affect the behavior of nanoparticles in a biological environment, thus it is important to measure. Thermogravimetric analysis (TGA) can be used to determine the amount of coating on the surface of the nanoparticle. TGA experiments run under inert atmosphere can also be used to determine residual metal content present in the sample. In this chapter, the TGA technique and experimental method are described.

Impact of structure and morphology of nanostructured ceria coating on AISI 304 oxidation kinetics

International Nuclear Information System (INIS)

Aadhavan, R.; Suresh Babu, K.

2017-01-01

Highlights: • Ceria coating reduced the oxidation kinetics of AISI304 by 3–4 orders. • Lower deposition rate (0.1 Å/s) resulted in dense and uniform coating. • Substrate temperature of 100 °C provided coating with smaller crystallite size. • Surface morphology of the coating has strong influence in oxidation protection. - Abstract: Nanostructured ceria-based coatings are shown to be protective against high-temperature oxidation of AISI 304 due to the dynamics of oxidation state and associated defects. However, the processing parameters of deposition have a strong influence in determining the structural and morphological aspects of ceria. The present work focuses on the effect of variation in substrate temperature (50–300 °C) and deposition rate (0.1–50 Å/s) of ceria in electron beam physical vapour evaporation method and correlates the changes in structure and morphology to high-temperature oxidation protection. Unlike deposition rate, substrate temperature exhibited a profound influence on crystallite size (7–18 nm) and oxygen vacancy concentration. Upon isothermal oxidation at 1243 K for 24 h, bare AISI 304 exhibited a linear mass gain with a rate constant of 3.0 ± 0.03 × 10"−"3 kg"2 m"−"4 s"−"1 while ceria coating lowered the kinetics by 3–4 orders. Though the thickness of the coating was kept constant at 2 μm, higher deposition rate offered one order lower protection due to the porous nature of the coating. Variation in the substrate temperature modulated the porosity as well as oxygen vacancy concentration and displayed the best protection for coatings deposited at moderate substrate temperature. The present work demonstrates the significance of selecting appropriate processing parameters to obtain the required morphology for efficient high-temperature oxidation protection.

Impact of structure and morphology of nanostructured ceria coating on AISI 304 oxidation kinetics

Energy Technology Data Exchange (ETDEWEB)

Aadhavan, R.; Suresh Babu, K., E-mail: sureshbabu.nst@pondiuni.edu.in

2017-07-31

Highlights: • Ceria coating reduced the oxidation kinetics of AISI304 by 3–4 orders. • Lower deposition rate (0.1 Å/s) resulted in dense and uniform coating. • Substrate temperature of 100 °C provided coating with smaller crystallite size. • Surface morphology of the coating has strong influence in oxidation protection. - Abstract: Nanostructured ceria-based coatings are shown to be protective against high-temperature oxidation of AISI 304 due to the dynamics of oxidation state and associated defects. However, the processing parameters of deposition have a strong influence in determining the structural and morphological aspects of ceria. The present work focuses on the effect of variation in substrate temperature (50–300 °C) and deposition rate (0.1–50 Å/s) of ceria in electron beam physical vapour evaporation method and correlates the changes in structure and morphology to high-temperature oxidation protection. Unlike deposition rate, substrate temperature exhibited a profound influence on crystallite size (7–18 nm) and oxygen vacancy concentration. Upon isothermal oxidation at 1243 K for 24 h, bare AISI 304 exhibited a linear mass gain with a rate constant of 3.0 ± 0.03 × 10{sup −3} kg{sup 2} m{sup −4} s{sup −1} while ceria coating lowered the kinetics by 3–4 orders. Though the thickness of the coating was kept constant at 2 μm, higher deposition rate offered one order lower protection due to the porous nature of the coating. Variation in the substrate temperature modulated the porosity as well as oxygen vacancy concentration and displayed the best protection for coatings deposited at moderate substrate temperature. The present work demonstrates the significance of selecting appropriate processing parameters to obtain the required morphology for efficient high-temperature oxidation protection.

Synchrotron radiation total reflection x-ray fluorescence analysis; of polymer coated silicon wafers

International Nuclear Information System (INIS)

Brehm, L.; Kregsamer, P.; Pianetta, P.

2000-01-01

It is well known that total reflection x-ray fluorescence (TXRF) provides an efficient method for analyzing trace metal contamination on silicon wafer surfaces. New polymeric materials used as interlayer dielectrics in microprocessors are applied to the surface of silicon wafers by a spin-coating process. Analysis of these polymer coated wafers present a new challenge for TXRF analysis. Polymer solutions are typically analyzed for bulk metal contamination prior to application on the wafer using inductively coupled plasma mass spectrometry (ICP-MS). Questions have arisen about how to relate results of surface contamination analysis (TXRF) of a polymer coated wafer to bulk trace analysis (ICP-MS) of the polymer solutions. Experiments were done to explore this issue using synchrotron radiation (SR) TXRF. Polymer solutions were spiked with several different concentrations of metals. These solutions were applied to silicon wafers using the normal spin-coating process. The polymer coated wafers were then measured using the SR-TXRF instrument set-up at the Stanford Synchrotron Radiation Laboratory (SSRL). Several methods of quantitation were evaluated. The best results were obtained by developing calibration curves (intensity versus ppb) using the spiked polymer coated wafers as standards. Conversion of SR-TXRF surface analysis results (atoms/cm 2 ) to a volume related concentration was also investigated. (author)

Nanoparticle Structures with (Un-)Hydrogenated Castor Oil as Hydrophobic Paper Coating.

Science.gov (United States)

Samyn, Pieter; Vonck, Leo; Stanssens, Dirk; Abbeele, Henk Van den

2018-05-01

The encapsulation of vegetable oils within an aqueous dispersion of polymer nanoparticles provides an alternative route to create functional paper coatings from renewable resources, by combining the presentation of hydrophobic moieties together with variations in roughness at the paper surface. The effects of two selected vegetable oil types, i.e., castor oil and hydrogenated castor oil (wax), are compared in terms of nanoparticle synthesis, coating hydrophobicity and surface gloss. The nanoparticles were synthesized by adding 50 wt.-% oil during imidization of poly(styrene-co-maleic anhydride) with ammonium hydroxide. From evaluation of the thermal properties, the nanoparticles have a high glass transition temperature that is suppressed in presence of oil. The nanoparticles with hydrogenated castor oil have higher imide content and better thermal stability compared to castor oil, in parallel with lower chemical reactivity of the hydrogenated oil and less interference with the imidization reaction. After deposition as a coating on paper, the physical coating properties are discussed in parallel with the coating chemistry and morphology or roughness at different scale lengths. The nanoparticle coatings with hydrogenated oil provides a multi-scale roughness with an open, porous nanoparticles structures and presentation of some amount free oil augmenting hydrophobicity towards a water contact angle of 128° (static contact angle) or 138° (advancing contact angle). The differences in surface coverage of coated papers in terms of imide and oil contents are confirmed by chemical Raman mapping. The differences in surface roughness are confirmed by non-contact profilometry, laser interferometry and atomic force microscopy.

Analysis of Crystal Structure of Fe3O4 Thin Films Based on Iron Sand Growth by Spin Coating Method

Science.gov (United States)

Rianto, D.; Yulfriska, N.; Murti, F.; Hidayati, H.; Ramli, R.

2018-04-01

Recently, iron sand used as one of base materials in the steel industry. However, the content of iron sand can be used as starting materials in sensor technology in the form of thin films. In this paper, we report the analysis of crystal structure of magnetite thin film based on iron sand from Tiram’s Beach. The magnetic content of sand separated by a permanent magnet, then it was milled at 30 hours milling time. In order to increase the purity of magnetite, it washed after milling using aquades under magnetic separation by a magnet permanent. The thin film has been prepared using iron (III) nitrate by sol–gel technique. The precursor is resulted by dissolving magnetite in oxalic acid and nitric acid. Then, solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. The X-Ray Diffraction is operated thin film characterization. The structure of magnetite has been studied based on X-Ray Peaks that correspond to magnetite content of thin films.

Laminated composite based on polyester geotextile fibers and polyurethane resin for coating wood structures

Directory of Open Access Journals (Sweden)

Yuri Andrey Olivato Assagra

2013-01-01

Full Text Available New environmental laws have restricted the use of hardwood trees in overhead power lines structures, such as, poles and cross-arms, leading companies to seek alternative materials. Reforested wood coated with polymeric resin has been proposed as an environmental friendly solution, with improved electrical properties and protection against external agents, e.g. moisture, ultraviolet radiation and fungi. However, the single thin layer of resin, normally applied on such structures reveal to be inefficient, due to be easily damage during handling. In this paper, we present a composite coating, based on geotextile fibers and polyurethane resin that is suitable for wooden structures. Results obtained from two different tree species (from managed and reforested areas coated with the composite reveal that the additional layer not only provided a stronger adhesion between wood and ccoating layer but also a further improvement in the electrical properties and better protection against abrasion and moisture.

Application of Nano-Structured Coatings for Mitigation of Flow-Accelerated Corrosion in Secondary Pipe Systems of Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Hyun; Kim, Jong Jin; Yoo, Seung Chang; Huh, Jae Hoon; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2014-05-15

Flow-accelerated corrosion (FAC) is a complex corrosion process combined with mechanical reaction with fluid. There were lots of research to mitigate FAC such as controlling temperature or water chemistry but in this research, we adopt active coating techniques especially nano-particle reinforced coatings. One of the general characteristics of FAC and its mitigation is that surface friction due to surface morphology makes a significant effect on FAC. Therefore to form a uniform coating layers, nano-particles including TiO2, SiC, Fe-Cr-W and Graphene were utilized. Those materials are known as greatly improve the corrosion resistance of substrates such as carbon steels but their effects on mitigation of FAC are not revealed clearly. Therefore in this research, the FAC resistive performance of nano-structured coatings were tested by electrochemical impedance spectroscopy (EIS) in room temperature 15 wt% sulfuric acid. As the flow-accelerated corrosion inhibitors in secondary piping system of nuclear power plants, various kinds of nano-structured coatings were prepared and tested in room-temperature electrochemical cells. SHS7740 with two types of Densifiers, electroless nickel plating with TiO2 are prepared. Electropolarization curves shows the outstanding corrosion mitigation performance of SHS7740 but EIS results shows the promising potential of Ni-P and Ni-P-TiO2 electroless nickel plating. For future work, high-temperature electrochemical analysis system will be constructed and in secondary water chemistry will be simulated.

Surface Coating Technique of Northern Black Polished Ware by the Microscopic Analysis

Directory of Open Access Journals (Sweden)

Dilruba Sharmin

2012-12-01

Full Text Available An organic substance has been identified in the top layer of Northern Black Polished Ware (NBPW excavated from the Wari-Boteshwar and Mahasthangarh sites in Bangladesh. NBPW is the most distinctive ceramic of Early Historic period and the technique of its surface gloss acquired numerous theories. This particular paper is an analytical study of collected NBPW sherds from these two sites including surface observations using binocular and scanning electron microscopes and Thin Section Analysis of potsherds. Thin section analysis identified two different layers of coating on the surface of the NBPW. One layer is a ‘slip’ (ground coat and the other is a ‘top layer or top coat ’. The slip was made from refined clay and the top layer was derived from organic substance. Microscopic analysis confirmed the solid and non-clayey characteristics of the top coat.

Analysis of Capillary Coating Die Flow in an Optical Fiber Coating Applicator

OpenAIRE

Kyoungjin Kim

2011-01-01

Viscous heating becomes significant in the high speed resin coating process of glass fibers for optical fiber manufacturing. This study focuses on the coating resin flows inside the capillary coating die of optical fiber coating applicator and they are numerically simulated to examine the effects of viscous heating and subsequent temperature increase in coating resin. Resin flows are driven by fast moving glass fiber and the pressurization at the coating die inlet, while ...

Multi-spectral Image Analysis for Astaxanthin Coating Classification

DEFF Research Database (Denmark)

Ljungqvist, Martin Georg; Ersbøll, Bjarne Kjær; Nielsen, Michael Engelbrecht

2011-01-01

Industrial quality inspection using image analysis on astaxanthin coating in aquaculture feed pellets is of great importance for automatic production control. In this study multi-spectral image analysis of pellets was performed using LDA, QDA, SNV and PCA on pixel level and mean value of pixels...

THE STRUCTURE AND PROPERTIES OF COMPOSITE LASER CLAD COATINGS WITH Ni BASED MATRIX WITH WC PARTICLES

Directory of Open Access Journals (Sweden)

Zita Iždinská

2010-09-01

Full Text Available In this work, the influence of the processing conditions on the microstructure and abrasive wear behavior of composite laser clad coatings with Ni based matrix reinforced with 50% WC particles is analyzed. Composite powder was applied in the form of coatings onto a mild steel substrate (Fe–0.17% C by different laser powers and cladding speeds. The microstructure of the coatings was analyzed by scanning electron microscopy (SEM. Tribological properties of coatings were evaluated by pin-on-disc wear test. It appeared that the hardness of the matrix of composite coatings decreases with increasing cladding speed. However, wear resistance of composite coatings with decreasing hardness of Ni based matrix increases. Significantly enhanced wear resistance of WC composite coatings in comparison with Ni based coatings is attributed to the hard phase structures in composite coatings.

Using Bonding Enamel-Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures

Science.gov (United States)

2010-02-01

Initial tests with enameled metal straps cracked all the test cylinders and straps would not pull out BUILDING STRONG® New Strong Durable Ties...BUILDING STRONG® Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures Principal Investigator: Steven C...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry

Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure and method of processing

Science.gov (United States)

Brown, Jr., Jesse J.; Hirschfeld, Deidre A.; Li, Tingkai

1993-12-07

Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)

2015-02-23

Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs.

Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

International Nuclear Information System (INIS)

Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke

2015-01-01

Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs

Evolution processes of the corrosion behavior and structural characteristics of plasma electrolytic oxidation coatings on AZ31 magnesium alloy

Science.gov (United States)

Chen, Dong; Wang, Ruiqiang; Huang, Zhiquan; Wu, Yekang; Zhang, Yi; Wu, Guorui; Li, Dalong; Guo, Changhong; Jiang, Guirong; Yu, Shengxue; Shen, Dejiu; Nash, Philip

2018-03-01

Evolution processes of the corrosion behavior and structural characteristics of the plasma electrolytic oxidation (PEO) coated AZ31 magnesium alloy were investigated by using scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), potentio-dynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Detached coating samples were fabricated by an electrochemical method and more details of the internal micro-structure of coatings were clearly observed on the fractured cross-section morphologies of the samples compared to general polished cross-section morphologies. Evolution mechanisms of the coating corrosion behavior in relation to the evolution of micro-structural characteristics were discussed in detail.

Investigation of DC magnetron-sputtered TiO2 coatings: Effect of coating thickness, structure, and morphology on photocatalytic activity

DEFF Research Database (Denmark)

Daviðsdóttir, Svava; Shabadi, Rajashekhara; Galca, Aurelian Catalin

2014-01-01

The photocatalytic performance of magnetron-sputtered titanium dioxide (TiO2) coatings of different thickness in anatase crystalline structure deposited on aluminium 1050 alloy substrates was investigated using a combination of photo-electrochemistry, methylene blue decomposition, and microscopic...

Structure and in vitro bioactivity of ceramic coatings on magnesium alloys by microarc oxidation

Science.gov (United States)

Yu, Huijun; Dong, Qing; Dou, Jinhe; Pan, Yaokun; Chen, Chuanzhong

2016-12-01

Magnesium and its alloys have the potential to serve as lightweight, degradable, biocompatible and bioactive orthopedic implants for load-bearing applications. However, severe local corrosion attack and high corrosion rate have prevented their further clinical use. Micro-arc oxidation (MAO) is proved to be a simple, controllable and efficient electrochemistry technique that can prepare protective ceramic coatings on magnesium alloys. In this paper, electrolyte containing silicate salts was used for microarc oxidation to form ceramic bioactive coatings on the ZK61 alloy substrate. The structure characteristics and element distributions of the coating were investigated by XRD, TEM, SEM and EPMA. The MAO samples were immersed in simulated body fluid (SBF) for 7 and 14 days, respectively. The surface characteristic of the immersed coatings was investigated by Fourier-transform infrared (FTIR) spectroscopy. The results show that these MAO coatings have low crystallinity and are mainly composed of MgO, Mg2SiO4 and Mg2Si2O6. The coating surface is porous. During the SBF immersion period, the nucleation and precipitation of bone-like apatites occur on the MAO coating surface. The corrosion resistance of the substrate is improved by the MAO coatings.

Structure and corrosion properties of PVD Cr-N coatings

International Nuclear Information System (INIS)

Liu, C.; Bi, Q.; Ziegele, H.; Leyland, A.; Matthews, A.

2002-01-01

PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, thicknesses, and surface roughnesses, by changing the N 2 flow rate, applying multilayering techniques and changing the substrate finish prior to coating. The microstructure of such coatings is investigated by various analytical techniques such as glancing angle x-ray diffraction and scanning electron microscopy, which are also correlated with the corrosion performance of the coated steel. Both dc polarization and ac impedance spectroscopy were employed to investigate the corrosion resistance of Cr-N coated steel in a 0.5N NaCl solution. It has been found that the N 2 flow rate during reactive deposition strongly determines the microstructure of Cr-N coatings (due to the changing nitrogen content in the film) and can thus affect the corrosion resistance of coated systems. The surface finish of the steel substrate also affects the uniformity and coverage of PVD coatings; grooves and inclusions on the original substrate can raise the susceptibility of coated

Coating and functionalization of high density ion track structures by atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Mättö, Laura [Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 (Finland); Szilágyi, Imre M., E-mail: imre.szilagyi@mail.bme.hu [Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, Budapest H-1111 (Hungary); MTA-BME Technical Analytical Research Group, Szent Gellért tér 4, Budapest H-1111 (Hungary); Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014 (Finland); Laitinen, Mikko [Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 (Finland); Ritala, Mikko; Leskelä, Markku [Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FI-00014 (Finland); Sajavaara, Timo [Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 (Finland)

2016-10-01

In this study flexible TiO{sub 2} coated porous Kapton membranes are presented having electron multiplication properties. 800 nm crossing pores were fabricated into 50 μm thick Kapton membranes using ion track technology and chemical etching. Consecutively, 50 nm TiO{sub 2} films were deposited into the pores of the Kapton membranes by atomic layer deposition using Ti({sup i}OPr){sub 4} and water as precursors at 250 °C. The TiO{sub 2} films and coated membranes were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray reflectometry (XRR). Au metal electrode fabrication onto both sides of the coated foils was achieved by electron beam evaporation. The electron multipliers were obtained by joining two coated membranes separated by a conductive spacer. The results show that electron multiplication can be achieved using ALD-coated flexible ion track polymer foils. - Highlights: • Porous Kapton membranes were obtained by ion track technology and chemical etching. • TiO{sub 2} films were deposited by ALD into the pores of the Kapton membranes. • TiO{sub 2} nanotube array was prepared by removing the polymer core. • MCP structures were obtained from the coated membranes. • Electron multiplication was achieved using the ALD-coated Kapton foils.

Mechanical and Thermal Analysis of Classical Functionally Graded Coated Beam

Directory of Open Access Journals (Sweden)

Toudehdehghan Abdolreza

2018-01-01

Full Text Available The governing equation of a classical rectangular coated beam made of two layers subjected to thermal and uniformly distributed mechanical loads are derived by using the principle of virtual displacements and based on Euler-Bernoulli deformation beam theory (EBT. The aim of this paper was to analyze the static behavior of clamped-clamped thin coated beam under thermo-mechanical load using MATLAB. Two models were considered for composite coated. The first model was consisting of ceramic layer as a coated and substrate which was metal (HC model. The second model was consisting of Functionally Graded Material (FGM as a coated layer and metal substrate (FGC model. From the result it was apparent that the superiority of the FGC composite against conventional coated composite has been demonstrated. From the analysis, the stress level throughout the thickness at the interface of the coated beam for the FGC was reduced. Yet, the deflection in return was observed to increase. Therefore, this could cater to various new engineering applications where warrant the utilization of material that has properties that are well-beyond the capabilities of the conventional or yesteryears materials.

Properties of nano structured Ag-TiO{sub 2} composite coating on stainless steel using RF sputtering method

Energy Technology Data Exchange (ETDEWEB)

Bakar, S. Abu; Jamuna-Thevi, K.; Abu, N.; Mohd Toff, M. R. [Advanced Materials Research Centre (AMREC), SIRIM Berhad, Lot 34, Jalan Hi- Tech 2/3, Kulim Hi-Tech Park, 09000 Kulim (Malaysia)

2012-07-02

RF Sputtering system is one of the Physical Vapour Deposition (PVD) methods that have been widely used to produce hard coating. This technique is used to deposit thin layers of metallic substrates such as stainless steel (SS). From this process, a good adhesiveness and wear resistance coating can be produced for biomedical applications. In this study, RF sputtering method was used to deposit TiO{sub 2}-Ag composite coatings via various deposition parameters. The parameters are RF power of 350W, gas composition (Ar: O{sub 2}) 50:5 and deposition time at 1, 2, 4 and 6 hours. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Raman spectroscopy were used to characterize surface area of coated samples. The formation of nanocrystalline thin film and the surface morphology were examined using SEM. The crystallite size of TiO{sub 2}-Ag composite coatings were estimated between 20-60 nm based on XRD analysis using Scherer equation and SEM evaluation. The Raman and XRD results suggested that the structure of the TiO{sub 2}-Ag consist of anatase and rutile phases. It also showed that the intensity of anatase peaks increased after samples undergone annealing process at 500 Degree-Sign C.

Development of a FE Model for the Stress Analysis of HTGR TRISO-coated particle fuel

International Nuclear Information System (INIS)

Cho, Moon Sung; Lee, Y. W.; Jeong, K. C.; Kim, Y. K.; Oh, S. C.; Chang, J. H.

2005-12-01

Finite element modelling of the stresses in TRISO-coated fuel particle under normal operating conditions was carried out with use of the structural analysis computer code ABAQUS. The FE model took into account the irradiation induced swelling and the creep of the PyC layers, the internal fission gas pressure that builds up during irradiation and the constant external ambient pressure. All of the inputs such as particle dimensions, swelling rates and creep rates of PyC layers and other mechanical properties used in these calculations were adopted from Miller's publication published in 1993. The FE model was verified against Miller's solution. Results of this model were found to be in good agreement with Miller's results. With use of the FE model, the static behavior of the TRISO-coated fuel particle, such as load shares, stress contours, stress variations as a function of fluence and shape changes of the TRISO -coated layers were investigated

Quantitative analysis and metallic coating thickness measurements by X-ray fluorescence

International Nuclear Information System (INIS)

Negrea, Denis; Ducu, Catalin; Malinovschi, Viorel; Moga, Sorin; Boicea, Niculae

2009-01-01

This work deals with the use of X-ray fluorescence (XRF) for determining the concentration and the coating thickness on metallic samples. The analysis method presented here may also be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF, such as the absorption coefficient of the system, primary radiation, fluorescent radiation and type of detection. For the coating thickness measurement it was used the substrate-line attenuation method and an algorithm was developed. Its advantage relies in the fact that no special calibration with standard samples having different layer thickness is needed. The samples used for evaluation were metallic pieces of iron with zinc-nickel coatings of different thickness obtained by electrochemical deposition. (authors)

Structure and corrosion properties of PVD Cr-N coatings

CERN Document Server

Liu, C; Ziegele, H; Leyland, A; Matthews, A

2002-01-01

PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, t...

Biocompatibility of Niobium Coatings

Directory of Open Access Journals (Sweden)

René Olivares-Navarrete

2011-09-01

Full Text Available Niobium coatings deposited by magnetron sputtering were evaluated as a possible surface modification for stainless steel (SS substrates in biomedical implants. The Nb coatings were deposited on 15 mm diameter stainless steel substrates having an average surface roughness of 2 mm. To evaluate the biocompatibility of the coatings three different in vitro tests, using human alveolar bone derived cells, were performed: cellular adhesion, proliferation and viability. Stainless steel substrates and tissue culture plastic were also studied, in order to give comparative information. No toxic response was observed for any of the surfaces, indicating that the Nb coatings act as a biocompatible, bioinert material. Cell morphology was also studied by immune-fluorescence and the results confirmed the healthy state of the cells on the Nb surface. X-ray diffraction analysis of the coating shows that the film is polycrystalline with a body centered cubic structure. The surface composition and corrosion resistance of both the substrate and the Nb coating were also studied by X-ray photoelectron spectroscopy and potentiodynamic tests. Water contact angle measurements showed that the Nb surface is more hydrophobic than the SS substrate.

Influence of silane on the structure of polystyrene prepared by sol-gel coatings via UV curing

Directory of Open Access Journals (Sweden)

Balbay Senay

2017-01-01

Full Text Available Light, heat, oxygen, moisture, ozone, atmospheric pollution and biological effects are the most important effectives wreak to chemical degradation in the polymer structure. In result of chemical degradation on the polymer consist of problems such as discoloration, brittleness, surface cracks, perspiration, crumbling, smell, surface acidity. In this work, it is aimed to improve the problem of the polystyrene (PS material against chemical degradation. For this reason, PS is coated with silica sol-gel hybrid coating. Silica sol-gel was synthesized by using vinyltrimethoxysilane (VTMS as a cross-linker and tetraethylorthosilicate (TEOS as a silica source. Firstly, four different pre-treatment technique (oven, vacuum oven, lyophilizer and freezing was studied to determine the most suitable pre-treatment technique for coating on PS substrate of sol-gel prepared with initial formulation (S1. A freezing technique gave the best results for coating sample. The change of surface colour of coated PS was measured by CIE L*a*b* methods. Secondly, the most suitable curing agent (Irgacure 184, Irgacure 819, Darocur 1173 and TiO2 as crystalline anatase phase was determined to coat the sol-gel on PS. It was determined to the lowest yellowing of PS surface hybrid coated as UV curing of TEOS sol modified by VTMS and TiO2 as photo-initiators. Finally, the chemical and morphological structure of the coated PS samples was determined by FT-IR and SEM instruments, respectively.

Crystal structure of the bacteriophage Qβ coat protein in complex with the RNA operator of the replicase gene.

Science.gov (United States)

Rumnieks, Janis; Tars, Kaspars

2014-03-06

The coat proteins of single-stranded RNA bacteriophages specifically recognize and bind to a hairpin structure in their genome at the beginning of the replicase gene. The interaction serves to repress the synthesis of the replicase enzyme late in infection and contributes to the specific encapsidation of phage RNA. While this mechanism is conserved throughout the Leviviridae family, the coat protein and operator sequences from different phages show remarkable variation, serving as prime examples for the co-evolution of protein and RNA structure. To better understand the protein-RNA interactions in this virus family, we have determined the three-dimensional structure of the coat protein from bacteriophage Qβ bound to its cognate translational operator. The RNA binding mode of Qβ coat protein shares several features with that of the widely studied phage MS2, but only one nucleotide base in the hairpin loop makes sequence-specific contacts with the protein. Unlike in other RNA phages, the Qβ coat protein does not utilize an adenine-recognition pocket for binding a bulged adenine base in the hairpin stem but instead uses a stacking interaction with a tyrosine side chain to accommodate the base. The extended loop between β strands E and F of Qβ coat protein makes contacts with the lower part of the RNA stem, explaining the greater length dependence of the RNA helix for optimal binding to the protein. Consequently, the complex structure allows the proposal of a mechanism by which the Qβ coat protein recognizes and discriminates in favor of its cognate RNA. © 2013.

AlSiTiN and AlSiCrN multilayer coatings: Effects of structure and surface composition on tribological behavior under dry and lubricated conditions

International Nuclear Information System (INIS)

Faga, Maria Giulia; Gautier, Giovanna; Cartasegna, Federico; Priarone, Paolo C.; Settineri, Luca

2016-01-01

Graphical abstract: - Highlights: • The demand for high performance nanostructured coatings has been increasing. • AlSiTiN and AlSiCrN nanocomposite coatings were deposited by PVD technique. • Coatings were analyzed in terms of structure, hardness and adhesion. • Tribological properties under dry and lubricated conditions were studied. • The effects of surface and bulk properties on friction evolution were assessed. - Abstract: Nanocomposite coatings have been widely studied over the last years because of their high potential in several applications. The increased interest for these coatings prompted the authors to study the tribological properties of two nanocomposites under dry and lubricated conditions (applying typical MQL media), in order to assess the influence of the surface and bulk properties on friction evolution. To this purpose, multilayer and nanocomposite AlSiTiN and AlSiCrN coatings were deposited onto tungsten carbide-cobalt (WC-Co) samples. Uncoated WC-Co materials were used as reference. Coatings were analyzed in terms of hardness and adhesion. The structure of the samples was assessed by X-ray diffraction (XRD), while the surface composition was studied by XPS analysis. Friction tests were carried out under both dry and lubricated conditions using an inox ball as counterpart. Both coatings showed high hardness and good adhesion to the substrate. As far as the friction properties are concerned, in dry conditions the surface properties affect the sliding contact at the early beginning, while bulk structure and tribolayer formation determine the main behavior. Only AlSiTiN coating shows a low and stable coefficient of friction (COF) under dry condition, while the use of MQL media results in a rapid stabilization of the COF for all the materials.

Surface structure of Cr0.5 Ti0.5N coatings after heavy ions irradiation and annealing

International Nuclear Information System (INIS)

Kislitsin, Sergey; Gorlachev, Igor; Uglov, Vladimir

2015-01-01

Results of surface structure investigations of TiCrN coating on carbon steel after irradiation by helium, krypton and xenon heavy ions are reported in the present publication. The series of Cr50Ti50N coatings on carbon steel with thickness of 50,..., 300 nm were formed by vacuum arc deposition techniques. Specimens with TiCrN coating on carbon steel were irradiated by low energy 4 He +1 (22 keV) and 4 He +2 (40 keV) ions and high energy Xe +18 and Kr +14 ions with energy of 1.5 MeV/nucleon. Fluence of He ions was 1.0x10 17 ion.cm -2 , fluence of Xe and Kr ions was 5x10 14 -1.0x10 15 ion.cm -2 , irradiation temperature did not exceed 150 deg. C. Study of surface structure was performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Methods of Roentgen diffractometry and Rutherford backscattering was applied for determination of structure and thickness of coating. In case of irradiation with Xe +18 and Kr +14 ions an investigation of surface morphology and structure was done after successive two hours vacuum annealing of irradiated samples at temperatures 400 deg. C, 500 deg. C and 600 deg. C. It was shown that after irradiation by Xe and Kr ions on the surface of coating convexities appear, surface density of which correlates with ion flux. In the case of Xe, ions irradiation generated convexities of spherical and elongated shape with dimensions ranging from ten to hundreds nm. In the case of Kr ions, only spherical globules were generated, dimensions of which are 10-30 nm. The most likely explanation of observed surface damage is that: convexities on the surface are generated at ion bombardment of specimens with coating. Convexities are the traces of ions passing through coating and they are due to structural reconstruction at energy release along a trajectory of ions braking. Convexities of elongated shape represent overlapping traces from two passing ions. When the projective range of Xe and Kr ions exceeds coating thickness, damage

Quantitative analysis and metallic coating thickness measurements by X-ray fluorescence

International Nuclear Information System (INIS)

Negrea, Denis; Ducu, Catalin; Malinovschi, Viorel; Moga, Sorin; Boicea, Niculae

2009-01-01

Full text: This paperwork covers the use of X-ray fluorescence (XRF) for determining the concentration and the coating thickness on metallic samples. The analysis method presented here may also be applicable to other coatings, providing that the elemental nature of the coating and substrate are compatible with the technical aspects of XRF, such as the absorption coefficient of the system, primary radiation, fluorescent radiation and type of detection. For the coating thickness measurement it was used the substrate-line attenuation method and a computing algorithm was developed. Its advantage relies in the fact that no special calibration with standard samples having different layer thickness is needed. The samples used for evaluation were metallic pieces of iron with zinc-nickel coatings of different thickness obtained by electrochemical deposition. (authors)

Titanium Nitride and Nitrogen Ion Implanted Coated Dental Materials

Directory of Open Access Journals (Sweden)

David W. Berzins

2012-07-01

Full Text Available Titanium nitride and/or nitrogen ion implanted coated dental materials have been investigated since the mid-1980s and considered in various applications in dentistry such as implants, abutments, orthodontic wires, endodontic files, periodontal/oral hygiene instruments, and casting alloys for fixed restorations. Multiple methodologies have been employed to create the coatings, but detailed structural analysis of the coatings is generally lacking in the dental literature. Depending on application, the purpose of the coating is to provide increased surface hardness, abrasion/wear resistance, esthetics, and corrosion resistance, lower friction, as well as greater beneficial interaction with adjacent biological and material substrates. While many studies have reported on the achievement of these properties, a consensus is not always clear. Additionally, few studies have been conducted to assess the efficacy of the coatings in a clinical setting. Overall, titanium nitride and/or nitrogen ion implanted coated dental materials potentially offer advantages over uncoated counterparts, but more investigation is needed to document the structure of the coatings and their clinical effectiveness.

Performance Analysis of Functionally Graded Coatings in Contact with Cylindrical Rollers

Directory of Open Access Journals (Sweden)

Reza Jahedi

2015-01-01

Full Text Available This work presents finite element analysis (FEA and results for rolling contact of a cylindrical roller on an elastic substrate coated by functionally graded material (FGM. The rolling process and the graded coating material property and layers arrangement are modeled using finite element codes which lead to a new methodology. This novel methodology provides a trend in determining surface contact stresses, deformations, contact zones, and energy dissipation through the contact area. Effects of stiffness ratio, friction, and exponentially variation of material property on the contact stresses and deformations are studied. Some of the results are verified with analytical solutions. The study results may be beneficial in graded coated cylindrical components analysis against rolling contact failure and wear.

The properties of electrodeposited Zn-Co coatings

Science.gov (United States)

Mahieu, J.; de Wit, K.; de Cooman, B. C.; de Boeck, A.

1999-10-01

The possibility of increasing the corrosion resistance of automotive sheet steel by electrodepositing with Zn-Co alloy coatings was investigated. Process variables during electrodeposition such as current density, electrolyte flow rate, and pH were varied in order to examine their influence on the electroplating process. Cobalt contents varying from 0.2 to 7 wt% were easily obtained. The influence of these process parameters on the characteristics of the coating could be related to the hydroxide suppression mechanism for anomalous codeposition. The structure and the morphology of the coatings were determined using SEM and XRD analysis. Application properties important for coating systems used in the automotive industry, such as friction behavior, adhesion, and corrosion behavior, were investigated on coatings with varying cobalt content. The corrosion resistance of the Zn-Co alloy layers was found to be better than that of pure zinc coatings.

Structure and Construction Assessment of the Surface Layer of Hardfaced Coating after Friction

Directory of Open Access Journals (Sweden)

Krzysztof Dziedzic

2017-09-01

Full Text Available The paper presents an analysis of the surface layer of Fe-Mn-C-B-Si-Ni-Cr alloy coating after friction with C45 steel. The coatings were obtained by arc welding (GMA. Flux-cored wires were used as a welding material. The flux-cored wires had a diameter of 2,4 mm. The tribological assessment was performed with the Amsler tribotester under dry friction conditions at unit pressures 10 MPa. The use of XPS spectroscopy allowed deep profile analysis of the surface layer. Based on the obtained results developed model of the surface layer for friction couple, hardfaced coating obtained from Fe-Mn-C-B-Si-Ni-Cr alloy – C45 steel. It was observed that the operational surface layer (OSL of hardfaced coatings contained oxides (B2O3, SiO2, NiO, Cr2O3, FeO, Fe3O4, Fe2O3, carbides (Fe3C, Cr7C3 and borides (FeB, Fe2B.

Computational image analysis of Suspension Plasma Sprayed YSZ coatings

Directory of Open Access Journals (Sweden)

Michalak Monika

2017-01-01

Full Text Available The paper presents the computational studies of microstructure- and topography- related features of suspension plasma sprayed (SPS coatings of yttria-stabilized zirconia (YSZ. The study mainly covers the porosity assessment, provided by ImageJ software analysis. The influence of boundary conditions, defined by: (i circularity and (ii size limits, on the computed values of porosity is also investigated. Additionally, the digital topography evaluation is performed: confocal laser scanning microscope (CLSM and scanning electron microscope (SEM operating in Shape from Shading (SFS mode measure surface roughness of deposited coatings. Computed values of porosity and roughness are referred to the variables of the spraying process, which influence the morphology of coatings and determines the possible fields of their applications.

Microstructure analysis of zirconium carbide layer on pyrocarbon-coated particles prepared by zirconium chloride vapor method

International Nuclear Information System (INIS)

Zhao Hongsheng; Liu Bing; Zhang Kaihong; Tang Chunhe

2012-01-01

Zirconium carbide (ZrC) layer on pyrocarbon-coated particles was successfully prepared in a fluidized bed coater furnace by chemical vapor deposition using a zirconium chloride (ZrCl 4 ) vapor method and quantitative controlling of the Zr-source through a ZrCl 4 powder feeder. The crystal phase, microstructure and chemical composition of ZrC-coating layer were analyzed using X-ray diffraction (XRD), optical metallographical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HR-TEM) and X-ray photoelectron spectroscopy (XPS). The results show that the deposited ZrC-coating layer has smooth and compact surface, no obvious holes, clear interface with dense pyrocarbon layer, and a thickness of 35 μm. The main phase of ZrC-coating layer is fcc-ZrC crystal, which is composed of small grains with the size of 20–50 nm. The grain size increases monotonously with the deposition temperature increasing. The main elements of ZrC-coating layer are Zr and C, and the Zr/C molar ratio is close to 1:1. The analysis of composition and crystal structure suggest that a stoichiometric fcc-ZrC crystal was obtained and no obvious preferred orientation of the grains was found.

Fabrication of Gold-coated 3-D Woodpile Structures for Mid-IR Thermal Emitters

Science.gov (United States)

Li, Shengkai; Moridani, Amir; Kothari, Rohit; Lee, Jae-Hwang; Watkins, James

3-D metallic woodpile nanostructures possess enhancements in thermal radiation that are both wavelength and polarization specific and are promising for thermal-optical devices for various applications including thermal photovoltaics, self-cooling devices, and chemical and bio-sensors. However, current fabrication techniques for such structures are limited by slow speed, small area capability, the need for expensive facilities and, in general, are not suitable for high-throughput mass production. Here we demonstrate a new strategy for the fabrication of 3D metallic woodpile structures. Well-defined TiO2 woodpile structures were fabricated using a layer-by-layer nanoimprint method using TiO2 nanoparticle ink dispersions. The TiO2 woodpile was then coated with a high purity, conformal gold film via reactive deposition in supercritical carbon dioxide. The final gold-coated woodpile structures exhibit strong spectral and polarization specific thermal emission enhancements. The fabrication method demonstrated here is promising for high-throughput, low-cost preparation of 3D metallic woodpile structures and other 3D nanostructures. Center for Hierarchical Manufacturing, NSF.

Finite element analysis of interface stress between neutron absorption coating and chop disk

International Nuclear Information System (INIS)

Tang Changliang; Zhang Xiaozhang; Jiang Lei; Dai Xingjian

2012-01-01

The performance of disk chopper is directly affected by bond strength between neutron absorption coating and chop disk. Based on the finite element analysis software ANSYS, the interface stress distribution under high speed centrifugal load was calculated, which was to investigate the effects of coating's elastic modulus, poisson ratio and coating thickness on the interfacial stress distribution. The results show that soft and tough coating can reduce the peak stress effectively, and coating thickness reducing is helpful to avoid the plastic failure of opening in the disk under high speed centrifugal load. (authors)

Structure and Properties of the Aluminide Coatings on the Inconel 625 Superalloy

Science.gov (United States)

Adamiak, Stanisław; Bochnowski, Wojciech; Dziedzic, Andrzej; Filip, Ryszard; Szeregij, Eugeniusz

2016-01-01

The research samples used in this study were based on the Inconel 625 alloy; the examined samples were coated with aluminide films deposited in a low-activity chemical vapor deposition (CVD) process. The samples' microstructure was investigated with optical and electron microscopy and energy dispersive X-ray spectroscopy analysis. Hardness measurements were performed using Vickers and Berkovich test methods. The adhesion of the aluminide coating was determined by fractography. It was shown that the fracture mechanism was different for the respective zones of the aluminide coating and the substrate material. The outer zone of the aluminide coating is characterized by an intercrystalline fracture, with a small contribution of transcrystalline fracture within individual grains (large crystallites in the bottom of the zone, composed of smaller crystallites, also show an intercrystalline fracture). The substrate material exhibited a ductile intercrystalline fracture. Based on this investigation, an increase of the microhardness of the material occurring at loads below 0.2 N was observed. When determining microhardness of aluminide coating it is necessary to take into account the optimal choice of the indentation tip.

Coherent gradient sensing method for measuring thermal stress field of thermal barrier coating structures

Directory of Open Access Journals (Sweden)

Kang Ma

2017-01-01

Full Text Available Coherent gradient sensing (CGS method can be used to measure the slope of a reflective surface, and has the merits of full-field, non-contact, and real-time measurement. In this study, the thermal stress field of thermal barrier coating (TBC structures is measured by CGS method. Two kinds of powders were sprayed onto Ni-based alloy using a plasma spraying method to obtain two groups of film–substrate specimens. The specimens were then heated with an oxy-acetylene flame. The resulting thermal mismatch between the film and substrate led to out-of-plane deformation of the specimen. The deformation was measured by the reflective CGS method and the thermal stress field of the structure was obtained through calibration with the help of finite element analysis. Both the experiment and numerical results showed that the thermal stress field of TBC structures can be successfully measured by CGS method.

Coating adherence in galvanized steel assessed by acoustic emission wavelet analysis

International Nuclear Information System (INIS)

Gallego, Antolino; Gil, Jose F.; Vico, Juan M.; Ruzzante, Jose E.; Piotrkowski, Rosa

2005-01-01

Coating-substrate adherence in galvanized steel is evaluated by acoustic emission wavelet analysis in scratch tests on hot-dip galvanized samples. The acoustic emission results are compared with optical and electron microscopy observations in order to understand coating features related to adherence and to establish criteria aimed at improving the manufacture process

The adhesion characteristics of protective coating materials for the containment structure in nuclear power plants

International Nuclear Information System (INIS)

Lee, Sang-Kook; Shin, Jae-Chul

2003-01-01

Protective coating materials used in the containment structures should be durable for the designed 30 to 40 year lifetime of a nuclear power plant. At the present, these materials have not yet been developed. Therefore it is very important to keep the durability of the protective coating materials through persistent maintenance, and in order to achieve this, understanding the adhesion characteristics of the coating materials is of utmost importance. Therefore, this study attempts to find any methods for durability maintenance of these protective coating materials. To accomplish these aims, this study applied an experimental deterioration environment condition relevant to Loss of Coolant Accident (LOCA) and Main Steam Line Break (MSLB), categorized as of Design Basis Accident (DBA), onto steel liner plate specimens covered with protective coating materials. Adhesion tests were performed on these deteriorated coating materials to characterize the physical properties and through these tests, the quantitative adhesion characteristics according to the history of deterioration environment were found

Structure and magnetic properties of iron-based soft magnetic composite with Ni-Cu-Zn ferrite-silicone insulation coating

Science.gov (United States)

Li, Wangchang; Wang, Wei; Lv, Junjun; Ying, Yao; Yu, Jing; Zheng, Jingwu; Qiao, Liang; Che, Shenglei

2018-06-01

This paper investigates the structure and magnetic properties of Ni-Cu-Zn ferrite-silicone coated iron-based soft magnetic composites (SMCs). Scanning electron microscopy coupled with a energy-dispersive spectroscopy (EDS) analysis revealed that the Ni-Cu-Zn ferrite and silicone resin were uniformly coated on the surface of iron powders. By controlling the composition of the coating layer, low total core loss of 97.7 mW/cm3 (eddy current loss of 48 mW/cm3, hysteresis loss of 49.7 mW/cm3, measured at 100 kHz and 0.02 T) and relatively high effective permeability of 72.5 (measured at 100 kHz) were achieved. In addition, the as-prepared SMCs displayed higher electrical resistivity, good magnetic characteristics over a wide range of frequencies (20-200 kHz) and ideal the D-C bias properties (more than 75% at H = 50 Oe). Furthermore, higher elastic modulus and hardness of SMCs, which means that the coating layer has good mechanical properties and is not easily damaged during the pressing process, were obtained in this paper. The results of this work indicate that the Ni-Cu-Zn ferrite-silicone coated SMCs have desirable properties which would make them suitable for application in the fields of the electric-magnetic switching devices, such as inductance coils, transformer cores, synchronous electric motors and resonant inductors.

Physicochemical characterization and failure analysis of military coating systems

Science.gov (United States)

Keene, Lionel Thomas

Modern military coating systems, as fielded by all branches of the U.S. military, generally consist of a diverse array of organic and inorganic components that can complicate their physicochemical analysis. These coating systems consist of VOC-solvent/waterborne automotive grade polyurethane matrix containing a variety of inorganic pigments and flattening agents. The research presented here was designed to overcome the practical difficulties regarding the study of such systems through the combined application of several cross-disciplinary techniques, including vibrational spectroscopy, electron microscopy, microtomy, ultra-fast laser ablation and optical interferometry. The goal of this research has been to determine the degree and spatial progression of weathering-induced alteration of military coating systems as a whole, as well as to determine the failure modes involved, and characterizing the impact of these failures on the physical barrier performance of the coatings. Transmission-mode Fourier Transform Infrared (FTIR) spectroscopy has been applied to cross-sections of both baseline and artificially weathered samples to elucidate weathering-induced spatial gradients to the baseline chemistry of the coatings. A large discrepancy in physical durability (as indicated by the spatial progression of these gradients) has been found between older and newer generation coatings. Data will be shown implicating silica fillers (previously considered inert) as the probable cause for this behavioral divergence. A case study is presented wherein the application of the aforementioned FTIR technique fails to predict the durability of the coating system as a whole. The exploitation of the ultra-fast optical phenomenon of femtosecond (10-15S) laser ablation is studied as a potential tool to facilitate spectroscopic depth profiling of composite materials. Finally, the interferometric technique of Phase Shifting was evaluated as a potential high-sensitivity technique applied to the

Tribological properties of coating films for core structure of HTGR

International Nuclear Information System (INIS)

Ozawa, Kenji; Kikuchi, Akiyoshi; Kawakami, Haruo

1985-01-01

The tribological properties of the various coating films used for the in-core structures of a high temperature gas-cooled experimental reactor were examined. When the explosion sprayed films of chrome carbide were applied for preventing galling in core restraining mechanism, the hardness of substrate materials exerted influence on the strength of the coating films. Also the effect of the surface roughness of the plasma sprayed films of zirconia on the sliding characteristics of the zirconia films and PGX graphite used for support plates was clarified. The coefficient of friction and the dependence of the amount of wear on surface pressure of these materials were examined. These results have been effectively utilized for the design of the test bodies of HENDEL-T2. In helium atmosphere, oxide film is hard to be formed on metal surface, especially on the contact surface of metals exposed to high temperature, there is the possibility to cause adhesion due to mutual diffusion and galling in sliding. As the means to prevent those, ceramic coating has been attempted. Sliding test, high pressure joining test, thermal cycle test and corrosion test in helium were carried out to evaluate the properties. (Koko, I.)

Impact of structure and morphology of nanostructured ceria coating on AISI 304 oxidation kinetics

Science.gov (United States)

Aadhavan, R.; Suresh Babu, K.

2017-07-01

Nanostructured ceria-based coatings are shown to be protective against high-temperature oxidation of AISI 304 due to the dynamics of oxidation state and associated defects. However, the processing parameters of deposition have a strong influence in determining the structural and morphological aspects of ceria. The present work focuses on the effect of variation in substrate temperature (50-300 °C) and deposition rate (0.1-50 Å/s) of ceria in electron beam physical vapour evaporation method and correlates the changes in structure and morphology to high-temperature oxidation protection. Unlike deposition rate, substrate temperature exhibited a profound influence on crystallite size (7-18 nm) and oxygen vacancy concentration. Upon isothermal oxidation at 1243 K for 24 h, bare AISI 304 exhibited a linear mass gain with a rate constant of 3.0 ± 0.03 × 10-3 kg2 m-4 s-1 while ceria coating lowered the kinetics by 3-4 orders. Though the thickness of the coating was kept constant at 2 μm, higher deposition rate offered one order lower protection due to the porous nature of the coating. Variation in the substrate temperature modulated the porosity as well as oxygen vacancy concentration and displayed the best protection for coatings deposited at moderate substrate temperature. The present work demonstrates the significance of selecting appropriate processing parameters to obtain the required morphology for efficient high-temperature oxidation protection.

Alfinated coating structure on HS6-5-2 (SW7M high speed steel

Directory of Open Access Journals (Sweden)

T. Szymczak

2010-10-01

Full Text Available The paper presents the results of immersion alfinated coating structure in AlSi5 silumin on HS6-5-2 (SW7M high speed steel. Alfinating bath temperature was 750 ± 5 ° C, time of sample immersion was τ = 180s. Thickness of obtained coating under specified conditions was g = 150μm. Manufactured coating consists of three layers of different construction phase. The first layer from the substrate „g1`” constructed with a AlFe phase consist of alloy additives constituents of HS6-5-2 (SW7M steel: W, Mo, V, Cr and Si. On it crystallizes the second layer „g1``” of AlFeWMoCr intermetallic phases also containing Si and small amount of V. Last, the outer layer „g2” of the coating is composed with silumin including AlFeWMoCrVSi intermetallic phases. Within all layers of the coating occurs carbides. Penetration of carbides to individual coating layers is mainly due to steel surface partial melting and crystallizing layers „g1`” and „g1``” by alfinating liquid and shifting into her of carbides as well as partial carbides rejection by crystallization front of intermetallic phases occurs in coating.

Determination of nanoparticle surface coatings and nanoparticle purity using microscale thermogravimetric analysis.

Science.gov (United States)

Mansfield, Elisabeth; Tyner, Katherine M; Poling, Christopher M; Blacklock, Jenifer L

2014-02-04

The use of nanoparticles in some applications (i.e., nanomedical, nanofiltration, or nanoelectronic) requires small samples with well-known purities and composition. In addition, when nanoparticles are introduced into complex environments (e.g., biological fluids), the particles may become coated with matter, such as proteins or lipid layers. Many of today's analytical techniques are not able to address small-scale samples of nanoparticles to determine purity and the presence of surface coatings. Through the use of an elevated-temperature quartz crystal microbalance (QCM) method we call microscale thermogravimetric analysis, or μ-TGA, the nanoparticle purity, as well as the presence of any surface coatings of nanomaterials, can be measured. Microscale thermogravimetric analysis is used to determine the presence and amount of surface-bound ligand coverage on gold nanoparticles and confirm the presence of a poly(ethylene glycol) coating on SiO2 nanoparticles. Results are compared to traditional analytical techniques to demonstrate reproducibility and validity of μ-TGA for determining the presence of nanoparticle surface coatings. Carbon nanotube samples are also analyzed and compared to conventional TGA. The results demonstrate μ-TGA is a valid method for quantitative determination of the coatings on nanoparticles, and in some cases, can provide purity and compositional data of the nanoparticles themselves.

Influence of coating defects on the corrosion behavior of cold sprayed refractory metals

International Nuclear Information System (INIS)

Kumar, S.; Rao, A. Arjuna

2017-01-01

Highlights: • Long duration immersion tests reveal inhomogeneous weight losses. • The weight loss for different coatings are well corroborated with the coating defects. • Chemical and micro structural analysis elucidates the reason behind the in homogeneous performance of different type of cold sprayed coatings. • In cold sprayed titanium, formation of oxide along the inter-splat boundary hinders the aggressive attack of the medium. - Abstract: The defects in the cold sprayed coatings are critical in the case of corrosion performances of the coatings in aggressive conditions. To understand the influence of coating defects on corrosion, immersion tests have been carried out in HF solution for the cold sprayed and heat treated Titanium, Tantalum and Niobium coatings. Long duration immersion tests reveal inhomogeneous weight losses of the samples prepared at different heat treatment conditions. The weight loss for different coatings has been well corroborated with the coating defects and microstructures. Chemical and micro structural analysis elucidates the reason behind the inhomogeneous performance of different type of cold sprayed coatings in corrosion medium. In the case of cold sprayed titanium, formation of stable oxide along the inter-splat boundary hinders the aggressive attack of the corrosion medium which is not so in other cases.

Porous Organic Nanolayers for Coating of Solid-state Devices

Science.gov (United States)

2011-01-01

Background Highly hydrophobic surfaces can have very low surface energy and such low surface energy biological interfaces can be obtained using fluorinated coatings on surfaces. Deposition of biocompatible organic films on solid-state surfaces is attained with techniques like plasma polymerization, biomineralization and chemical vapor deposition. All these require special equipment or harsh chemicals. This paper presents a simple vapor-phase approach to directly coat solid-state surfaces with biocompatible films without any harsh chemical or plasma treatment. Hydrophilic and hydrophobic monomers were used for reaction and deposition of nanolayer films. The monomers were characterized and showed a very consistent coating of 3D micropore structures. Results The coating showed nano-textured surface morphology which can aid cell growth and provide rich molecular functionalization. The surface properties of the obtained film were regulated by varying monomer concentrations, reaction time and the vacuum pressure in a simple reaction chamber. Films were characterized by contact angle analysis for surface energy and with profilometer to measure the thickness. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the chemical composition of the coated films. Variations in the FTIR results with respect to different concentrations of monomers showed the chemical composition of the resulting films. Conclusion The presented approach of vapor-phase coating of solid-state structures is important and applicable in many areas of bio-nano interface development. The exposure of coatings to the solutions of different pH showed the stability of the coatings in chemical surroundings. The organic nanocoating of films can be used in bio-implants and many medical devices. PMID:21569579

Porous Organic Nanolayers for Coating of Solid-state Devices

Directory of Open Access Journals (Sweden)

Asghar Waseem

2011-05-01

Full Text Available Abstract Background Highly hydrophobic surfaces can have very low surface energy and such low surface energy biological interfaces can be obtained using fluorinated coatings on surfaces. Deposition of biocompatible organic films on solid-state surfaces is attained with techniques like plasma polymerization, biomineralization and chemical vapor deposition. All these require special equipment or harsh chemicals. This paper presents a simple vapor-phase approach to directly coat solid-state surfaces with biocompatible films without any harsh chemical or plasma treatment. Hydrophilic and hydrophobic monomers were used for reaction and deposition of nanolayer films. The monomers were characterized and showed a very consistent coating of 3D micropore structures. Results The coating showed nano-textured surface morphology which can aid cell growth and provide rich molecular functionalization. The surface properties of the obtained film were regulated by varying monomer concentrations, reaction time and the vacuum pressure in a simple reaction chamber. Films were characterized by contact angle analysis for surface energy and with profilometer to measure the thickness. Fourier Transform Infrared Spectroscopy (FTIR analysis revealed the chemical composition of the coated films. Variations in the FTIR results with respect to different concentrations of monomers showed the chemical composition of the resulting films. Conclusion The presented approach of vapor-phase coating of solid-state structures is important and applicable in many areas of bio-nano interface development. The exposure of coatings to the solutions of different pH showed the stability of the coatings in chemical surroundings. The organic nanocoating of films can be used in bio-implants and many medical devices.

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)

Tribological and corrosion behaviour of electroless Ni-B coating possessing a blackberry like structure

Science.gov (United States)

Bülbül, Ferhat; Altun, Hikmet; Küçük, Özkan; Ezirmik, Vefa

2012-08-01

This study aims to evaluate the tribological and corrosion properties of the electroless Ni-B coating deposited on AISI 304 stainless steels. The microstructure of the coating was characterized using x-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). XRD analysis revealed that the prepared coating possessed an amorphous character. SEM-EDS investigation also indicated that a non-stoichiometric Ni-B coating was deposited with a columnar growth mechanism on the stainless steel substrate and the morphology of the growth surface was blackberry-like. The hardness and tribological properties were characterized by microhardness and a pin-on-disc wear test. The electroless Ni-B coated sample had a higher degree of hardness, a lower friction coefficient and a lower wear rate than the uncoated substrate. The electrochemical potentiodynamic polarization method was used to evaluate the corrosion resistance of the coating. The electroless Ni-B coating offered cathodic protection on the substrate by acting as a sacrificial anode although it was electrochemically more reactive than the stainless steel substrate.

Au{sup 3+} ion implantation on FTO coated glasses: Effect on structural, electrical, optical and phonon properties

Energy Technology Data Exchange (ETDEWEB)

Sahu, Bindu; Dey, Ranajit; Bajpai, P.K., E-mail: bajpai.pk1@gmail.com

2017-06-01

Highlights: • Effects of 11.00 MeV Au{sup 3+} ions implanted in FTO coated (thickness ≈300 nm) silicate glasses at varying fluence. • Metal clustering near the surface and subsurface region below glass-FTO interface changes electrical and optical properties significantly. • Ion implantation does not affect the crystalline structure of the coated films; however, the tetragonal distortion increases with increasing ion fluence. • Significant surface reconstruction takes place with ion beam fluence; The average roughness also decreases with increasing fluence. • The sheet resistivity increases with increasing fluence. • Raman analysis also corroborates the re-crystallization process inducing due to ion implantation. • Optical properties of the implanted surfaces changes significantly. - Abstract: Effects of 11.00 MeV Au{sup 3+} ions implanted in FTO coated (thickness ≈300 nm) silicate glasses on structural, electrical optical and phonon behavior have been explored. It has been observed that metal clustering near the surface and sub-surface region below glass-FTO interface changes electrical and optical properties significantly. Ion implantation does not affect the crystalline structure of the coated films; however, the unit cell volume decreases with increase in fluence and the tetragonal distortion (c/a ratio) also decreases systematically in the implanted samples. The sheet resistivity of the films increases from 11 × 10{sup −5} ohm-cm (in pristine) to 7.5 × 10{sup −4} ohm-cm for highest ion beam fluence ≈10{sup 15} ions/cm{sup 2}. The optical absorption decreases with increasing fluence whereas, the optical transmittance as well as reflectance increases with increasing fluence. The Raman spectra are observed at ∼530 cm{sup −1} and ∼1103 cm{sup −1} in pristine sample. The broad band at 530 cm{sup −1} shifts towards higher wave number in the irradiated samples. This may be correlated with increased disorder and strain relaxation in

Structure, phases, and mechanical response of Ti-alloy bioactive glass composite coatings

Energy Technology Data Exchange (ETDEWEB)

Nelson, G.M.; Nychka, J.A. [Department of Chemical and Materials Engineering, University of Alberta, 7th Floor, Electrical and Computer Engineering Research Facility, Edmonton, Alberta T6G 2V4 (Canada); McDonald, A.G., E-mail: andre2@ualberta.ca [Department of Mechanical Engineering, University of Alberta, 4-9 Mechanical Engineering Building, Edmonton, Alberta T6G 2G8 (Canada)

2014-03-01

Porous titanium alloy-bioactive glass composite coatings were manufactured via the flame spray deposition process. The porous coatings, targeted for orthodontic and bone-fixation applications, were made from bioactive glass (45S5) powder blended with either commercially pure titanium (Cp-Ti) or Ti-6Al-4V alloy powder. Two sets of spray conditions, two metallic particle size distributions, and two glass particle size distributions were used for this study. Negative control coatings consisting of pure Ti-6Al-4V alloy or Cp-Ti were sprayed under both conditions. The as-sprayed coatings were characterized through quantitative optical cross-sectional metallography, X-ray diffraction (XRD), and ASTM Standard C633 tensile adhesion testing. Determination of the porosity and glassy phase distribution was achieved by using image analysis in accordance with ASTM Standard E2109. Theoretical thermodynamic and heat transfer modeling was conducted to explain experimental observations. Thermodynamic modeling was performed to estimate the flame temperature and chemical environment for each spray condition and a lumped capacitance heat transfer model was developed to estimate the temperatures attained by each particle. These models were used to establish trends among the choice of alloy, spray condition, and particle size distribution. The deposition parameters, alloy composition, and alteration of the feedstock powder size distribution had a significant effect on the coating microstructure, porosity, phases present, mechanical response, and theoretical particle temperatures that were attained. The most promising coatings were the Ti-6Al-4V-based composite coatings, which had bond strength of 20 ± 2 MPa (n = 5) and received reinforcement and strengthening from the inclusion of a glassy phase. It was shown that the use of the Ti-6Al-4V-bioactive glass composite coatings may be a superior choice due to the possible osteoproductivity from the bioactive glass, the potential ability to

Chemical state analysis of conversion coatings by SR-XPS and TEY-XANES

CERN Document Server

Noro, H; Nagoshi, M

2002-01-01

Chromate coatings on galvanized steel have been studied by Synchrotron Radiation (SR) based techniques that include X-ray Photoelectron Spectroscopy (XPS) and Total-Electron-Yield X-ray Absorption Near Edge Structure (TEY-XANES). Non-destructive depth profiling of the coatings by SR-XPS reveals the enhancement of Cr sup 6 sup + in the outer surface. TEY-XANES spectroscopy based on simple specimen current measurement is demonstrated as an effective technique for analyzing chemical states of conversion coatings on general bulk substrates. The sampling depth of this technique, which exceeds several tens of nanometer, is determined by the penetration length of Auger electrons excited by X-ray and the inelastic mean free path of secondary electrons excited by inelastically scattered Auger electrons. The chemical states of phosphoric acid added chromate coatings are studied using this technique. The phosphoric acid is taken into the chromate coatings as partially changed into zinc and chromium phosphates, and the r...

Protective silicon coating for nanodiamonds using atomic layer deposition

International Nuclear Information System (INIS)

Lu, J.; Wang, Y.H.; Zang, J.B.; Li, Y.N.

2007-01-01

Ultrathin silicon coating was deposited on nanodiamonds using atomic layer deposition (ALD) from gaseous monosilane (SiH 4 ). The coating was performed by sequential reaction of SiH 4 saturated adsorption and in situ decomposition. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to investigate the structural and morphological properties of the coating. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to compare the thermal stability of nanodiamonds before and after silicon coating. The results confirmed that the deposited cubic phase silicon coating was even and continuous. The protective silicon coating could effectively improve the oxidation resistance of nanodiamonds in air flow, which facilitates the applications of nanodiamonds that are commonly hampered by their poor thermal stability

Protective silicon coating for nanodiamonds using atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Lu, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Wang, Y.H. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Zang, J.B. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China) and College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China)]. E-mail: diamondzjb@163.com; Li, Y.N. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China)

2007-01-30

Ultrathin silicon coating was deposited on nanodiamonds using atomic layer deposition (ALD) from gaseous monosilane (SiH{sub 4}). The coating was performed by sequential reaction of SiH{sub 4} saturated adsorption and in situ decomposition. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to investigate the structural and morphological properties of the coating. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to compare the thermal stability of nanodiamonds before and after silicon coating. The results confirmed that the deposited cubic phase silicon coating was even and continuous. The protective silicon coating could effectively improve the oxidation resistance of nanodiamonds in air flow, which facilitates the applications of nanodiamonds that are commonly hampered by their poor thermal stability.

Multipactor suppression by micro-structured gold/silver coatings for space applications

Science.gov (United States)

Nistor, Valentin; González, Luis A.; Aguilera, Lydya; Montero, Isabel; Galán, Luis; Wochner, Ulrich; Raboso, David

2014-10-01

The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of Ku-band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4-6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were diminished by 25% with respect to the values attained in the tests of the standard anti-multipactor coating, Alodine.

Hydrolysis and stability of thin pulsed plasma polymerised maleic anhydride coatings

DEFF Research Database (Denmark)

Drews, Joanna Maria; Launay, Héléne; Hansen, Charles M.

2008-01-01

Abstract The stability of plasma polymerised layers has become important because of their widespread use. This study explored the hydrolysis and degradation stability of coatings of plasma polymerised maleic anhydride. Coatings made with different plasma parameters were exposed to aqueous media...... of different pH as a function of time. ATR-FTIR was used for structure analysis and a toluidine blue staining method allowed quantitative analysis of the hydrolysis of anhydride groups to acid groups. Coatings with constant thickness were obtained at different plasma powers and layers with varying thickness...

Nanofilm-coated long-period fiber grating humidity sensors for corrosion detection in structural health monitoring

Science.gov (United States)

Zheng, Shijie; Zhu, Yinian; Krishnaswamy, Sridhar

2011-04-01

Long-period gratings (LPGs) have shown their significant promising applications in sensors owing to the attractive features that they posses such as small size, immunity for electromagnetic interference, geometric versatility, multiplexing capability, and resistance to corrosive and hazardous environments. Recent researches have revealed that LPGs written on the standard optical fibers could be used as a powerful sensing platform for structural health monitoring. In this work, we inscribe LPGs into SMF-28 optical fiber by focused-beam CO2 laser, demonstrating as a refractive index sensor for nondestructive chemical detections in the civil infrastructures. Although evanescent-field based LPG sensors have been applied in quantitatively monitoring chemical analytes including moisture, chloride, and corrosion by-product, etc., the sensitivity, selectivity, and response time as well as thermo-stability of such sensors are still the issues for some special purposes. In order to improve those characteristics of the sensors, we propose two types of nano-film to be coated in grating region by electrostatic self-assembly (ESA) deposition processing. The primary coating does not affect on LPG transmission parameters such as resonance wavelength and its intensity that can be used for sensing, but it increases the sensitivity to refractive index change of surrounding material. The secondary coating is for selectively absorption of analyte molecule of interest. Response time of the nanofilm-coated LPG sensor is dependent on the analyte absorption and de-absorption rates as well as the thicknesses of the coating materials, which is also investigated. Multi-channel sensor system is being designed to monitor different analytes simultaneously, which is continuing to further explore the monitoring of structural health conditions through in situ measurements of corrosion in the concrete structures.

The development of chemically vapor deposited mullite coatings for the corrosion protection of SiC

Energy Technology Data Exchange (ETDEWEB)

Auger, M.; Hou, P.; Sengupta, A.; Basu, S.; Sarin, V. [Boston Univ., MA (United States)

1998-05-01

Crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance the corrosion and oxidation resistance of the substrate. Current research has been divided into three distinct areas: (1) Development of the deposition processing conditions for increased control over coating`s growth rate, microstructure, and morphology; (2) Analysis of the coating`s crystal structure and stability; (3) The corrosion resistance of the CVD mullite coating on SiC.

Thermal interaction between WC-Co coating and steel substrate in process of HVOF spraying

International Nuclear Information System (INIS)

Guilemany, J.M.; Sobolev, V.V.; Nutting, J.; Dong, Z.; Calero, J.A.

1994-01-01

The WC-Co powders can be used to produce good adhesive and wear resistant HVOF thermal spray coatings on steel and light alloys substrates. In order to understand the properties of this kind of coating, the phases which are present in the coatings and structure changes during post heat treatments have been investigated. Although the coating properties depend very much on the structure developed in the substrate-coating interfacial region it has not been yet investigated in detail. The present study is devoted to the experimental and theoretical analysis of this interfacial region. The structure characterization has been performed mainly through the use of transmission electron microscopy. To provide a theoretical investigation a realistic prediction model of the process has been developed and on its base the mathematical simulation of the substrate-coating thermal interaction has been undertaken

Coatings for transport industry

Directory of Open Access Journals (Sweden)

Krzysztof LUKASZKOWICZ

2014-09-01

Full Text Available The investigations concerned structural analysis, as well as mechanical properties and wear resistant of MeN/DLC double-layer coating deposited by hybrid PVD/PACVD method. In sliding dry friction conditions, after the break-in time, the friction coefficient for the investigated elements is set in the range between 0.03-0.06.

Structural, photoluminescent and photocatalytic properties of TiO{sub 2}:Eu{sup 3+} coatings formed by plasma electrolytic oxidation

Energy Technology Data Exchange (ETDEWEB)

Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs [University of Belgrade, Faculty of Physics, Studentski trg 12–16, Belgrade 11000 (Serbia); Radić, Nenad; Grbić, Boško [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade 11000 (Serbia); Maletić, Slavica [University of Belgrade, Faculty of Physics, Studentski trg 12–16, Belgrade 11000 (Serbia); Stefanov, Plamen [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Pačevski, Aleksandar [University of Belgrade, Faculty of Mining and Geology, Đušina 7, 11000 Belgrade (Serbia); Vasilić, Rastko [University of Belgrade, Faculty of Physics, Studentski trg 12–16, Belgrade 11000 (Serbia)

2016-05-01

Graphical abstract: - Highlights: • TiO{sub 2}:Eu{sup 3+} coatings are formed by plasma electrolytic oxidation (PEO). • Photoluminescence is related to transitions of Eu{sup 3+} from level {sup 5}D{sub 0} to levels {sup 7}F{sub J}. • Eu{sup 3+} ions occupy non-inversion symmetry sites in the coatings. • PEO time is an important factor affecting photocatalytic activity. - Abstract: In this paper, we used plasma electrolytic oxidation (PEO) of titanium in water solution containing 10 g/L Na{sub 3}PO{sub 4}·12H{sub 2}O + 2 g/L Eu{sub 2}O{sub 3} powder for preparation of TiO{sub 2}:Eu{sup 3+} coatings. The surfaces of obtained coatings exhibit a typical PEO porous structure. The energy dispersive X-ray spectroscopy analysis showed that the coatings are mainly composed of Ti, O, P, and Eu; it is observed that Eu content in the coatings increases with PEO time. The X-ray diffraction analysis indicated that the coatings are crystallized and composed of anatase and rutile TiO{sub 2} phases, with anatase being the dominant one. X-ray photoelectron spectroscopy revealed that Ti 2p spin-orbit components of TiO{sub 2}:Eu{sup 3+} coatings are shifted towards higher binding energy, with respect to pure TiO{sub 2} coatings, suggesting that Eu{sup 3+} ions are incorporated into TiO{sub 2} lattice. Diffuse reflectance spectroscopy showed that TiO{sub 2}:Eu{sup 3+} coatings exhibit evident red shift with respect to the pure TiO{sub 2} coatings. Photoluminescence (PL) emission spectra of TiO{sub 2}:Eu{sup 3+} coatings are characterized by sharp emission bands in orange–red region ascribed to f–f transitions of Eu{sup 3+} ions from excited level {sup 5}D{sub 0} to lower levels {sup 7}F{sub J} (J = 0, 1, 2, 3, and 4). The excitation PL spectra of TiO{sub 2}:Eu{sup 3+} coatings can be divided into two regions: the broad band region from 250 nm to 350 nm associated with charge transfer state of Eu{sup 3+} and the series of sharp peaks in the range from 350 nm to 550 nm

Application of Genetic Algorithm to the Design Optimization of Complex Energy Saving Glass Coating Structure

Science.gov (United States)

Johar, F. M.; Azmin, F. A.; Shibghatullah, A. S.; Suaidi, M. K.; Ahmad, B. H.; Abd Aziz, M. Z. A.; Salleh, S. N.; Shukor, M. Md

2014-04-01

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

Application of genetic algorithm to the design optimization of complex energy saving glass coating structure

International Nuclear Information System (INIS)

Johar, F M; Azmin, F A; Suaidi, M K; Ahmad, B H; Aziz, M Z A Abd; Salleh, S N; Shukor, M Md; Shibghatullah, A S

2014-01-01

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

CONDENSED MATTER: STRUCTURE, THERMAL AND MECHANICAL PROPERTIES: Pair interaction of bilayer-coated nanoscopic particles

Science.gov (United States)

Zhang, Qi-Yi

2009-02-01

The pair interaction between bilayer membrane-coated nanosized particles has been explored by using the self-consistent field (SCF) theory. The bilayer membranes are composed of amphiphilic polymers. For different system parameters, the pair-interaction free energies are obtained. Particular emphasis is placed on the analysis of a sequence of structural transformations of bilayers on spherical particles, which occur during their approaching processes. For different head fractions of amphiphiles, the asymmetrical morphologies between bilayers on two particles and the inverted micellar intermediates have been found in the membrane fusion pathway. These results can benefit the fabrication of vesicles as encapsulation vectors for drug and gene delivery.

In Vivo Electrochemical Analysis of a PEDOT/MWCNT Neural Electrode Coating

Directory of Open Access Journals (Sweden)

Nicolas A. Alba

2015-10-01

Full Text Available Neural electrodes hold tremendous potential for improving understanding of brain function and restoring lost neurological functions. Multi-walled carbon nanotube (MWCNT and dexamethasone (Dex-doped poly(3,4-ethylenedioxythiophene (PEDOT coatings have shown promise to improve chronic neural electrode performance. Here, we employ electrochemical techniques to characterize the coating in vivo. Coated and uncoated electrode arrays were implanted into rat visual cortex and subjected to daily cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS for 11 days. Coated electrodes experienced a significant decrease in 1 kHz impedance within the first two days of implantation followed by an increase between days 4 and 7. Equivalent circuit analysis showed that the impedance increase is the result of surface capacitance reduction, likely due to protein and cellular processes encapsulating the porous coating. Coating’s charge storage capacity remained consistently higher than uncoated electrodes, demonstrating its in vivo electrochemical stability. To decouple the PEDOT/MWCNT material property changes from the tissue response, in vitro characterization was conducted by soaking the coated electrodes in PBS for 11 days. Some coated electrodes exhibited steady impedance while others exhibiting large increases associated with large decreases in charge storage capacity suggesting delamination in PBS. This was not observed in vivo, as scanning electron microscopy of explants verified the integrity of the coating with no sign of delamination or cracking. Despite the impedance increase, coated electrodes successfully recorded neural activity throughout the implantation period.

The system of quantum structures coated with the diamond-like carbon for silicon solar cells

International Nuclear Information System (INIS)

Efimov, V.P.; Abyzov, A.S.; Luchaninov, A.A.; Omarov, A.O.; Strel'nitskij, V.E.

2010-01-01

The peculiarity of the process of amorphous diamond-like carbon coating deposition on the surface of Si photoelectric cell with quantum filaments, which was irradiated by the electrons and heavy multi-charge ions, have been investigated. The experimental results on the investigations of the optical characteristics of the nitrogen doped hydrogenated diamond-like carbon a-C:(H,N) coatings were presented. The parameters of the process of a-C:(H,N) coating deposition on the surfaces of disordered Si semiconductors structures were optimized for the purpose of minimizing optical reflection coefficient from the front surface of the crystal and supplying its mechanical durability.

Structurally Integrated Coatings for Wear and Corrosion

Energy Technology Data Exchange (ETDEWEB)

Beardsley, M. Brad; Sebright, Jason L.

2008-11-18

Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

THE INVESTIGATION OF INFLUENCE OF LASER RADIATION ON THE STRUCTURE AND MECHANICAL PROPERTIES OF COMPOSITE ELECTROLYTIC NICKEL COATING

Directory of Open Access Journals (Sweden)

V. A. Zabludovsky

2013-09-01

Full Text Available Purpose. Investigation of laser radiation effect on the structure and mechanical properties of electrodeposited nickel composite coatings containing ultrafine diamonds. Methodology. Electrodeposition of nickel films was carried out with the addition of a standard solution of ultrafine diamonds (UFD on laser-electrolytic installation, built on the basis of the gas-discharge CO2 laser. Mechanical testing the durability of coatings were performed on a machine with reciprocating samples in conditions of dry friction against steel. The spectral microanalysis of the elemental composition of the film - substrate was performed on REMMA-102-02. Findings. Research of nickel coatings and modified ultrafine diamond electrodeposited under external stimulation laser demonstrated the dependence of the structure and mechanical properties of composite electrolytic coating (CEC, and the qualitative and quantitative distribution of nanodiamond coprecipitated from an electrodeposition method. Originality. The effect of laser light on the process of co-precipitation of the UFD, which increases the micro-hardness and wear resistance of electrolytic nickel coatings was determined. Practical value. The test method of laser-stimulated composite electrolytic nickel electrodeposition coating is an effective method of local increase in wear resistance of metal coatings, which provides durability save performance (functional properties of the surface.

Synthesis of Polyhydroxybutyrate Particles with Micro-to-Nanosized Structures and Application as Protective Coating for Packaging Papers

Directory of Open Access Journals (Sweden)

Vibhore Kumar Rastogi

2016-12-01

Full Text Available This study reports on the development of bio-based hydrophobic coatings for packaging papers through deposition of polyhydroxybutyrate (PHB particles in combination with nanofibrillated cellulose (NFC and plant wax. In the first approach, PHB particles in the micrometer range (PHB-MP were prepared through a phase-separation technique providing internally-nanosized structures. The particles were transferred as a coating by dip-coating filter papers in the particle suspension, followed by sizing with a carnauba wax solution. This approach allowed partial to almost full surface coverage of PHB-MP over the paper surface, resulting in static water contact angles of 105°–122° and 129°–144° after additional wax coating. In the second approach, PHB particles with submicron sizes (PHB-SP were synthesized by an oil-in-water emulsion (o/w solvent evaporation method and mixed in aqueous suspensions with 0–7 wt % NFC. After dip-coating filter papers in PHB-SP/NFC suspensions and sizing with a carnauba wax solution, static water contact angles of 112°–152° were obtained. The intrinsic properties of the particles were analyzed by scanning electron microscopy, thermal analysis and infrared spectroscopy, indicating higher crystallinity for PHB-SP than PHB-MP. The chemical interactions between the more amorphous PHB-MP particles and paper fibers were identified as an esterification reaction, while the morphology of the NFC fibrillar network was playing a key role as the binding agent in the retention of more crystalline PHB-SP at the paper surface, hence contributing to higher hydrophobicity.

Synthesis of Polyhydroxybutyrate Particles with Micro-to-Nanosized Structures and Application as Protective Coating for Packaging Papers.

Science.gov (United States)

Rastogi, Vibhore Kumar; Samyn, Pieter

2016-12-30

This study reports on the development of bio-based hydrophobic coatings for packaging papers through deposition of polyhydroxybutyrate (PHB) particles in combination with nanofibrillated cellulose (NFC) and plant wax. In the first approach, PHB particles in the micrometer range (PHB-MP) were prepared through a phase-separation technique providing internally-nanosized structures. The particles were transferred as a coating by dip-coating filter papers in the particle suspension, followed by sizing with a carnauba wax solution. This approach allowed partial to almost full surface coverage of PHB-MP over the paper surface, resulting in static water contact angles of 105°-122° and 129°-144° after additional wax coating. In the second approach, PHB particles with submicron sizes (PHB-SP) were synthesized by an oil-in-water emulsion (o/w) solvent evaporation method and mixed in aqueous suspensions with 0-7 wt % NFC. After dip-coating filter papers in PHB-SP/NFC suspensions and sizing with a carnauba wax solution, static water contact angles of 112°-152° were obtained. The intrinsic properties of the particles were analyzed by scanning electron microscopy, thermal analysis and infrared spectroscopy, indicating higher crystallinity for PHB-SP than PHB-MP. The chemical interactions between the more amorphous PHB-MP particles and paper fibers were identified as an esterification reaction, while the morphology of the NFC fibrillar network was playing a key role as the binding agent in the retention of more crystalline PHB-SP at the paper surface, hence contributing to higher hydrophobicity.

Synthesis of Polyhydroxybutyrate Particles with Micro-to-Nanosized Structures and Application as Protective Coating for Packaging Papers

Science.gov (United States)

Rastogi, Vibhore Kumar; Samyn, Pieter

2016-01-01

This study reports on the development of bio-based hydrophobic coatings for packaging papers through deposition of polyhydroxybutyrate (PHB) particles in combination with nanofibrillated cellulose (NFC) and plant wax. In the first approach, PHB particles in the micrometer range (PHB-MP) were prepared through a phase-separation technique providing internally-nanosized structures. The particles were transferred as a coating by dip-coating filter papers in the particle suspension, followed by sizing with a carnauba wax solution. This approach allowed partial to almost full surface coverage of PHB-MP over the paper surface, resulting in static water contact angles of 105°–122° and 129°–144° after additional wax coating. In the second approach, PHB particles with submicron sizes (PHB-SP) were synthesized by an oil-in-water emulsion (o/w) solvent evaporation method and mixed in aqueous suspensions with 0–7 wt % NFC. After dip-coating filter papers in PHB-SP/NFC suspensions and sizing with a carnauba wax solution, static water contact angles of 112°–152° were obtained. The intrinsic properties of the particles were analyzed by scanning electron microscopy, thermal analysis and infrared spectroscopy, indicating higher crystallinity for PHB-SP than PHB-MP. The chemical interactions between the more amorphous PHB-MP particles and paper fibers were identified as an esterification reaction, while the morphology of the NFC fibrillar network was playing a key role as the binding agent in the retention of more crystalline PHB-SP at the paper surface, hence contributing to higher hydrophobicity. PMID:28336839

Effect of substrate bias on structure and properties of the TiN coatings obtained in the PVD process

International Nuclear Information System (INIS)

Dobrzanski, L.A.; Kwasny, W.

2003-01-01

The paper presents investigation results of the field of deposition parameters on structure and mechanical properties of the TiN coatings obtained by magnetron sputtering in the vacuum furnace onto the ASP 30 sintered high speed steel. Effect of sputtering parameters on chemical and phase composition, thickness, microhardness and roughness parameter. The characteristic structure and surface topography of the analyzed coatings are presented. (author)

Structural features of spin-coated thin films of binary AsxS100−x chalcogenide glass system

International Nuclear Information System (INIS)

Cook, J.; Slang, S.; Golovchak, R.; Jain, H.; Vlcek, M.; Kovalskiy, A.

2015-01-01

Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As x S 100−x (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic–inorganic interface. - Highlights: • As–S spin-coated chalcogenide thin films with different As/S were fabricated. • XPS measurements support the cluster-like structure of spin-coated films. • As 2 O 3 was confirmed as the composition of precipitate formed during dissolution. • Lack of As–As bonds explains the observed photostability of the thin films

Bimetallic low thermal-expansion panels of Co-base and silicide-coated Nb-base alloys for high-temperature structural applications

International Nuclear Information System (INIS)

Rhein, R.K.; Novak, M.D.; Levi, C.G.; Pollock, T.M.

2011-01-01

Research highlights: → Low net thermal expansion bimetallic structural lattice constructed. → Temperatures on the order of 1000 deg. C reached. → Improved silicide coating for niobium alloy developed. - Abstract: The fabrication and high temperature performance of low thermal expansion bimetallic lattices composed of Co-base and Nb-base alloys have been investigated. A 2D sheet lattice with a coefficient of thermal expansion (CTE) lower than the constituent materials of construction was designed for thermal cycling to 1000 deg. C with the use of elastic-plastic finite element analyses. The low CTE lattice consisted of a continuous network of the Nb-base alloy C-103 with inserts of high CTE Co-base alloy Haynes 188. A new coating approach wherein submicron alumina particles were incorporated into (Nb, Cr, Fe) silicide coatings was employed for oxidation protection of the Nb-base alloy. Thermal gravimetric analysis results indicate that the addition of submicron alumina particles reduced the oxidative mass gain by a factor of four during thermal cycling, increasing lifetime. Bimetallic cells with net expansion of 6 x 10 -6 /deg. C and 1 x 10 -6 /deg. C at 1000 deg. C were demonstrated and their measured thermal expansion characteristics were consistent with analytical models and finite element analysis predictions.

Analysis of the epitope structure of Plum pox virus coat protein.

Science.gov (United States)

Candresse, Thierry; Saenz, Pilar; García, Juan Antonio; Boscia, Donato; Navratil, Milan; Gorris, Maria Teresa; Cambra, Mariano

2011-05-01

Typing of the particular Plum pox virus (PPV) strain responsible in an outbreak has important practical implications and is frequently performed using strain-specific monoclonal antibodies (MAbs). Analysis in Western blots of the reactivity of 24 MAbs to a 112-amino-acid N-terminal fragment of the PPV coat protein (CP) expressed in Escherichia coli showed that 21 of the 24 MAbs recognized linear or denaturation-insensitive epitopes. A series of eight C-truncated CP fragments allowed the mapping of the epitopes recognized by the MAbs. In all, 14 of them reacted to the N-terminal hypervariable region, defining a minimum of six epitopes, while 7 reacted to the beginning of the core region, defining a minimum of three epitopes. Sequence comparisons allowed the more precise positioning of regions recognized by several MAbs, including those recognized by the 5B-IVIA universal MAb (amino acids 94 to 100) and by the 4DG5 and 4DG11 D serogroup-specific MAbs (amino acids 43 to 64). A similar approach coupled with infectious cDNA clone mutagenesis showed that a V74T mutation in the N-terminus of the CP abolished the binding of the M serogroup-specific AL MAb. Taken together, these results provide a detailed positioning of the epitopes recognized by the most widely used PPV detection and typing MAbs.

Influence of monomer on structure, processing and application characteristics of UV curable urethane acrylate composite coatings

International Nuclear Information System (INIS)

Grigale-Sorocina, Z; Kalnins, M; Gross, K A

2016-01-01

Increased interest in the esthetical natural nail coatings have encouraged more in-depth studies particularly of UV curable coatings: their formation, processing, structure, characteristics and removing. Typical requirement for nail coatings is good adhesion, but preferably for the short time of functioning (usual 2-4 weeks). This study investigated the impact of four different monomers (tertiobutyl cyclohexyl acrylate (TBCHA), ethylene glycol dimethacrylate (EGDMA), tetrahydrofurfuryl acrylate (THFA), hydroxypropyl methacrylate (HPMA)) to viscosity of uncured mixture and degree of conversion, mechanical properties, surface gloss, micro hardness and adhesion loss for cured films. Specific coating application requires comparatively high coating flexibility and stability of deformation characteristics. This can be achieved with composition containing 30% of monomer TBCHA, what shows ultimate elongation ε B = 0,23 - 0,24, modulus of elasticity E = 670-710 MPa and comparatively constant properties in 72 hours (ΔE = 1.3%, Δε B =6.0%). A composition with 40% of TBCHA shows the fastest coating destruction achieving adhesion loss within 3 min. (paper)

Effect of surface topological structure and chemical modification of flame sprayed aluminum coatings on the colonization of Cylindrotheca closterium on their surfaces

Science.gov (United States)

Chen, Xiuyong; He, Xiaoyan; Suo, Xinkun; Huang, Jing; Gong, Yongfeng; Liu, Yi; Li, Hua

2016-12-01

Biofouling is one of the major problems for the coatings used for protecting marine infrastructures during their long-term services. Regulation in surface structure and local chemistry is usually the key for adjusting antifouling performances of the coatings. In this study, flame sprayed multi-layered aluminum coatings with micropatterned surfaces were constructed and the effects of their surface structure and chemistry on the settlement of typical marine diatoms were investigated. Micropatterned topographical morphology of the coatings was constructed by employing steel mesh as a shielding plate during the coating deposition. A silicone elastomer layer for sealing and interconnection was further brush-coated on the micropatterned coatings. Additional surface modification was made using zwitterionic molecules via DOPA linkage. The surface-modified coatings resist effectively colonization of Cylindrotheca closterium. This is explained by the quantitative examination of a simplified conditioning layer that deteriorated adsorption of bovine calf serum proteins on the zwitterionic molecule-treated samples is revealed. The colonization behaviors of the marine diatoms are markedly influenced by the micropatterned topographical morphology. Either the surface micropatterning or the surface modification by zwitterionic molecules enhances antimicrobial ability of the coatings. However, the combined micropatterned structure and zwitterionic modification do not show synergistic effect. The results give insight into anti-corrosion/fouling applications of the modified aluminum coatings in the marine environment.

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.

Highly transparent, stable, and superhydrophobic coatings based on gradient structure design and fast regeneration from physical damage

International Nuclear Information System (INIS)

Chen, Zao; Liu, Xiaojiang; Wang, Yan; Li, Jun; Guan, Zisheng

2015-01-01

Graphical abstract: - Highlights: • Highly transparent, stable, and superhydrophobic PET film was fabricated by dip-coating way. • The gradient structure is beneficial to both hydrophobicity and transparency. • The superhydrophobic PET film after physical damage can quickly regain by one-step spary. • The fabrication method is available for various substrates and large-scale production. - Abstract: Optical transparency, mechanical flexibility, and fast regeneration are important factors to expand the application of superhydrophobic surfaces. Herein, we fabricated highly transparent, stable, and superhydrophobic coatings through a novel gradient structure design by versatile dip-coating of silica colloid particles (SCPs) and diethoxydimethysiliane cross-linked silica nanoparticles (DDS-SNPs) on polyethylene terephthalate (PET) film and glass, followed by the modification of octadecyltrichlorosiliane (OTCS). When the DDS concentration reached 5 wt%, the modified SCPs/DDS-SNPs coating exhibited a water contact angle (WCA) of 153° and a sliding angle (SA) <5°. Besides, the average transmittance of this superhydrophobic coating on PET film and glass was increased by 2.7% and 1% in the visible wavelength, respectively. This superhydrophobic coating also showed good robustness and stability against water dropping impact, ultrasonic damage, and acid solution. Moreover, the superhydrophobic PET film after physical damage can quickly regain the superhydrophobicity by one-step spray regenerative solution of dodecyltrichlorosilane (DTCS) modified silica nanoparticles at room temperature. The demonstrated method for the preparation and regeneration of superhydrophobic coating is available for different substrates and large-scale production at room temperature.

Seed coat development in Velloziaceae: primary homology assessment and insights on seed coat evolution.

Science.gov (United States)

Sousa-Baena, Mariane S; de Menezes, Nanuza L

2014-09-01

• Seed coat characteristics have historically been used to infer taxonomic relationships and are a potential source of characters for phylogenetic reconstruction. In particular, seed coat morphoanatomy has never been studied in detail in Velloziaceae. One character based on seed surface microsculpture has been used in phylogenies, but was excluded from recent studies owing to problems in primary homology. This work aimed to clarify the origin and general composition of seed coat cell layers in Velloziaceae and to propose hypotheses of primary homology among seed characters.• Seed coat development of 24 Velloziaceae species, comprising nine genera, and one species of Pandanaceae (outgroup) was studied using standard anatomical methods. Developmental data were interpreted in the light of a recently published phylogeny.• Eight types of seed coat were identified. Whereas the most common type has four distinct cell layers (two-layered tegmen and testa), we encountered much more variation in seed coat composition than previously reported, the analysis of which revealed some potential synapomorphies. For instance, an exotesta with spiral thickenings may be a synapomorphy of Barbacenia.• Our results showed that the character states previously used in phylogenies are not based on homologous layers and that the same state was misattributed to species exhibiting quite different seed coats. This study is a first step toward a better understanding of seed coat structure evolution in Velloziaceae. © 2014 Botanical Society of America, Inc.

Improvement of structural and electrochemical properties of commercial LiCoO2 by coating with LaF3

International Nuclear Information System (INIS)

Yang Zhanxu; Qiao Qingdong; Yang Wensheng

2011-01-01

Highlights: → LaF 3 has been introduced as a new coating material for the LiCoO 2 cathode. → The LaF 3 -coated LiCoO 2 showed an excellent overcharge tolerance and structure stability. → The thermal stability of the LaF 3 -coated cathode is significantly enhanced. Therefore, LaF 3 is a probably potential coating material. - Abstract: Commercial LiCoO 2 has been modified with LaF 3 as a new coating material. The surface modified materials were characterized by X-ray diffraction (XRD), transmission electronic microscopy (TEM), field emission scanning electron microscopy (FE-SEM), auger electron spectroscopy (AES) and galvanostatic charge-discharge cycling. The LaF 3 -coated LiCoO 2 had an initial discharge specific capacity of 177.4 mAh g -1 within the potential ranges 2.75-4.5 V (vs. Li/Li + ), and showed a good capacity retention of 90.9% after 50 cycles. It was found that the overcharge tolerance of the coated cathode was significantly better than that of the pristine LiCoO 2 under the same conditions - the capacity retention of the pristine LiCoO 2 was 62.3% after 50 cycles. The improvement could be attributed to the LaF 3 coating layer that hinders interaction between LiCoO 2 and electrolyte and stabilizes the structure of LiCoO 2 . Moreover, DSC showed that the coated LiCoO 2 had a higher thermal stability than the pristine LiCoO 2 .

Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

Science.gov (United States)

Tang, Fujian

This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

Micro/Nano Structural Tantalum Coating for Enhanced Osteogenic Differentiation of Human Bone Marrow Stem Cells

OpenAIRE

Ding Ding; Youtao Xie; Kai Li; Liping Huang; Xuebin Zheng

2018-01-01

Recently, tantalum has been attracting much attention for its anticorrosion resistance and biocompatibility, and it has been widely used in surface modification for implant applications. To improve its osteogenic differentiation of human bone marrow stem cells (hBMSCs), a micro/nano structure has been fabricated on the tantalum coating surface through the combination of anodic oxidation and plasma spraying method. The morphology, composition, and microstructure of the modified coating were co...

The preparation and corrosion behaviors of MAO coating on AZ91D with rare earth conversion precursor film

Energy Technology Data Exchange (ETDEWEB)

Cai Jingshun [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); Cao Fahe, E-mail: nelson_cao@zju.edu.cn [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); Chang Linrong; Zheng Junjun [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); Zhang Jianqing; Cao Chunan [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016 (China)

2011-02-01

A novel kind of micro-arc oxidation (MAO) coating was prepared on magnesium alloy surface coated with rare earth conversion film (RE-film) in an alkaline aluminum oxidation electrolyte by AC power source. Inspection of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy, the structure and composition of MAO coating formed on AZ91D with RE-film under different applied voltages were investigated and the performance of the optimized MAO coating compared with the MAO coating directly formed on magnesium alloy. As the pretreatment of magnesium alloy with RE-film, the cerium oxides can be incorporated into the MAO coatings, reduce porosity of the MAO coating surface and enhance the thickness of MAO coating. These structure features and the cerium oxides incorporated into the MAO coating result in greatly improved corrosion resistance. Base on electrochemistry impedance spectroscopy (EIS) measurement, the electronic structure and composition analysis of the MAO coating, a double-layer structure, with a compact inner layer and a porous outer layer, of the coating was proposed for understanding its corrosion process.

The preparation and corrosion behaviors of MAO coating on AZ91D with rare earth conversion precursor film

International Nuclear Information System (INIS)

Cai Jingshun; Cao Fahe; Chang Linrong; Zheng Junjun; Zhang Jianqing; Cao Chunan

2011-01-01

A novel kind of micro-arc oxidation (MAO) coating was prepared on magnesium alloy surface coated with rare earth conversion film (RE-film) in an alkaline aluminum oxidation electrolyte by AC power source. Inspection of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy, the structure and composition of MAO coating formed on AZ91D with RE-film under different applied voltages were investigated and the performance of the optimized MAO coating compared with the MAO coating directly formed on magnesium alloy. As the pretreatment of magnesium alloy with RE-film, the cerium oxides can be incorporated into the MAO coatings, reduce porosity of the MAO coating surface and enhance the thickness of MAO coating. These structure features and the cerium oxides incorporated into the MAO coating result in greatly improved corrosion resistance. Base on electrochemistry impedance spectroscopy (EIS) measurement, the electronic structure and composition analysis of the MAO coating, a double-layer structure, with a compact inner layer and a porous outer layer, of the coating was proposed for understanding its corrosion process.

Composite Ni-Co-fly ash coatings on 5083 aluminium alloy

Energy Technology Data Exchange (ETDEWEB)

Panagopoulos, C.N., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Georgiou, E.P.; Tsopani, A.; Piperi, L. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece)

2011-03-15

Ni-Co-fly ash coatings were deposited on zincate treated 5083 wrought aluminium alloy substrates with the aid of the electrodeposition technique. Structural and chemical characterization of the produced composite coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-Co-fly ash coatings were found to consist of a crystalline Ni-Co solid solution with dispersed fly ash particles. In addition, chemical analysis of the Ni-Co matrix showed that it consisted of 80 wt.% Ni and 20 wt.% Co. The co-deposition of fly ash particles leads to a significant increase of the microhardness of the coating. The corrosion behaviour of the Ni-Co-fly ash/zincate coated aluminium alloy, in a 0.3 M NaCl solution (pH = 3.5), was studied by means of potentiodynamic corrosion experiments.

Terahertz pulsed imaging as an advanced characterisation tool for film coatings--a review

DEFF Research Database (Denmark)

Haaser, Miriam; Gordon, Keith C; Strachan, Clare J

2013-01-01

spectroscopy. In this review TPI is introduced and various applications of the technique in pharmaceutical coating analysis are discussed. These include evaluation of coating thickness, uniformity, surface morphology, density, defects and buried structures as well as correlation between TPI measurements...

The Effect of Rare Earth on the Structure and Performance of Laser Clad Coatings

Science.gov (United States)

Bao, Ruiliang; Yu, Huijun; Chen, Chuanzhong; Dong, Qing

Laser cladding is one kind of advanced surface modification technology and has the abroad prospect in making the wear-resistant coating on metal substrates. However, the application of laser cladding technology does not achieve the people's expectation in the practical production because of many defects such as cracks, pores and so on. The addiction of rare earth can effectively reduce the number of cracks in the clad coating and enhance the coating wear-resistance. In the paper, the effects of rare earth on metallurgical quality, microstructure, phase structure and wear-resistance are analyzed in turns. The preliminary discussion is also carried out on the effect mechanism of rare earth. At last, the development tendency of rare earth in the laser cladding has been briefly elaborated.

Structural, mechanical and tribocorrosion behaviour in artificial seawater of CrN/AlN nano-multilayer coatings on F690 steel substrates

Science.gov (United States)

Ma, Fuliang; Li, Jinlong; Zeng, Zhixiang; Gao, Yimin

2018-01-01

The CrN monolayer and CrN/AlN nano-multilayer coating were successfully fabricated by reactive magnetron sputtering on F690 steel. The results show that CrN monolayer exhibits a face centered cubic crystalline structure with (111) preferred orientation and CrN/AlN nano-multilayer coating has a (200) preferred orientation. This design of the nano-multilayer can interrupt the continuous growth of columnar crystals making the coating denser. The CrN/AlN nano-multilayer coating has a better wear resistance and corrosion resistance compared with the CrN monolayer coating. The tribocorrosion tests reveal that the evolution of potential and current density of F690 steel and CrN monolayer or CrN/AlN nano-multilayer coating see an opposite trend under the simultaneous action of wear and corrosion, which is attributed to that F690 steel is a non-passive material and PVD coatings is a passive material. The nano-multilayer structure has a good ;Pore Sealing Effect;, and the corrosive solution is difficult to pass through the coating to corrode the substrate.

Biomimetic hierarchical growth and self-assembly of hydroxyapatite/titania nanocomposite coatings and their biomedical applications

International Nuclear Information System (INIS)

Nathanael, A. Joseph; Im, Young Min; Oh, Tae Hwan; Yuvakkumar, R.; Mangalaraj, D.

2015-01-01

Graphical abstract: - Highlights: • Novel ‘bowtie’ like biomimetic HA/TiO 2 nanocomposite coatings were prepared. • Simple sol–gel method was used to achieve this novel structure. • Details analysis confirms the formation of bowtie like structure in many ways. • Their functional analysis showed their enhanced activity for biomedical application. - Abstract: This article describes a systematic study of the biomimetic hierarchical growth of hydroxyapatite (HA)/titania (TiO 2 ) nanocomposite layered coatings applied by a simple sol–gel dip coating method. Highly stable HA and TiO 2 sols were prepared prior to inducing biomimetic hierarchical growth. Initially, the samples formed a small leaf like structure; however, increasing the dipping cycle resulted in formation of an elongated seed-like structure. Increasing the number of dipping cycles further resulted in a ‘bowtie’ or straw-bale like nanowire structure with a length of 500 nm and a width of 100 nm. Each nanowire like structure had a width of very few nanometers. The crystalline structures, micro/nano structures and surface properties of the coatings were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy respectively. In vitro cellular assays revealed that the growth of the cells in the ‘bowtie’ like structure improved over other samples

Biomimetic hierarchical growth and self-assembly of hydroxyapatite/titania nanocomposite coatings and their biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Nathanael, A. Joseph, E-mail: ajosephnc@yahoo.com [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan (Korea, Republic of); Im, Young Min [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan (Korea, Republic of); Oh, Tae Hwan, E-mail: taehwanoh@ynu.ac.kr [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan (Korea, Republic of); Yuvakkumar, R. [Department of Nanomaterials Engineering, Chungnam National University, Daejeon (Korea, Republic of); Mangalaraj, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore (India)

2015-03-30

Graphical abstract: - Highlights: • Novel ‘bowtie’ like biomimetic HA/TiO{sub 2} nanocomposite coatings were prepared. • Simple sol–gel method was used to achieve this novel structure. • Details analysis confirms the formation of bowtie like structure in many ways. • Their functional analysis showed their enhanced activity for biomedical application. - Abstract: This article describes a systematic study of the biomimetic hierarchical growth of hydroxyapatite (HA)/titania (TiO{sub 2}) nanocomposite layered coatings applied by a simple sol–gel dip coating method. Highly stable HA and TiO{sub 2} sols were prepared prior to inducing biomimetic hierarchical growth. Initially, the samples formed a small leaf like structure; however, increasing the dipping cycle resulted in formation of an elongated seed-like structure. Increasing the number of dipping cycles further resulted in a ‘bowtie’ or straw-bale like nanowire structure with a length of 500 nm and a width of 100 nm. Each nanowire like structure had a width of very few nanometers. The crystalline structures, micro/nano structures and surface properties of the coatings were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy respectively. In vitro cellular assays revealed that the growth of the cells in the ‘bowtie’ like structure improved over other samples.

Structure and mechanical properties of Ti-Si-C coatings deposited by magnetron sputtering

International Nuclear Information System (INIS)

Koutzaki, S.H.; Krzanowski, J.E.; Nainaparampril, J.J.

2001-01-01

Nanostructured coatings consisting of mixed carbide phases can provide a potential means to developing superhard coatings. Heterogeneous nanostructured coatings can be obtained by either deposition of multilayer structures or by depositing film compositions that undergo a natural phase separation due to thermodynamic immiscibility. In the present work, we have taken the latter approach, and deposited films by radio frequency cosputtering from dual carbide targets. We have examined a number of ternary carbide systems, and here we report the results obtained on Ti-Si-C films with a nominal (Ti 1-x Si x )C stoichiometry and with x≤0.31. It was found that the nanoindentation hardness increased with Si content, and the maximum hardness achieved was nearly twice that of sputter-deposited TiC. We further analyzed these films using high-resolution transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction. Since cubic SiC has an x-ray pattern almost identical to that of TiC, the extent of phase separation could not be determined by that method. However, XRD did demonstrate a general disordering of the films with increasing SiC content. In addition, a mottled structure was observed in high-resolution TEM images of the Si-containing films, confirming microstructural effects due to the Si additions

THE RESEARCH TECHNIQUES FOR ANALYSIS OF MECHANICAL AND TRIBOLOGICAL PROPERTIES OF COATING-SUBSTRATE SYSTEMS

Directory of Open Access Journals (Sweden)

Kinga CHRONOWSKA-PRZYWARA

2014-06-01

Full Text Available The article presents research techniques for the analysis of both mechanical and tribological properties of thin coatings applied on highly loaded machine elements. In the Institute of Machine Design and Exploitation, AGH University of Science and Technology students of the second level of Mechanical Engineering study tribology attending laboratory class. Students learn on techniques for mechanical and tribological testing of thin, hard coatings deposited by PVD and CVD technologies. The program of laboratories contains micro-, nanohardness and Young's modulus measurements by instrumental indentations and analysys of coating to substrate adhesion by scratch testing. The tribological properties of the coating-substrate systems are studied using various techniques, mainly in point contact load conditions with ball-on-disc and block-on-ring tribomiters as well as using ball cratering method in strongly abrasive suspensions.

Factors affecting the hot-dip zinc coatings structure

International Nuclear Information System (INIS)

Sere, P.R.; Cuclcasi, J.D.; Elsner, C.I.; Sarli, A.R.

1997-01-01

Coating solidification during hot-dip galvanizing is a very complex process due to Al-Fe, Al-Fe-Zn and Fe-Zn intermetallic compounds development . Fe-Zn intermetallics are brittle and detrimental for the coating ductility, while the diffusion towards the surface of a segregated insoluble alloying such as antimonium causes the sheet darkness. Steel of different roughness were hot-dip galvanized under different operation conditions using a laboratory scale simulator. The effect of steel roughness and process parameters upon coating characteristics were analysed. Experimental results showed that the steel roughness affects the coating thickness, zinc grain size and texture as well as the out-bursts development, while the process parameters affects the Fe 2 Al 5 morphology and antimonium segregation. (Author) 11 refs

Pressure analysis in the fabrication process of TRISO UO2-coated fuel particle

International Nuclear Information System (INIS)

Liu Malin; Shao Youlin; Liu Bing

2012-01-01

Highlights: ► The pressure signals during the real TRISO UO2-coated fuel particle fabrication process. ► A new relationship about the pressure drop change and the coated fuel particles properties. ► The proposed relationship is validated by experimental results during successive coating. ► A convenient method for monitoring the fluidized state during coating process. - Abstract: The pressure signals in the coating furnace are obtained experimentally from the TRISO UO 2 -coated fuel particle fabrication process. The pressure signals during the coating process are analyzed and a simplified relationship about the pressure drop change due to the coated layer is proposed based on the spouted bed hydrodynamics. The change of pressure drop is found to be consistent with the change of the combination factor about particle density, bed density, particle diameter and static bed height, during the successive coating process of the buffer PyC, IPyC, SiC and OPyC layer. The newly proposed relationship is validated by the experimental values. Based on this relationship, a convenient method is proposed for real-time monitoring the fluidized state of the particles in a high-temperature coating process in the spouted bed. It can be found that the pressure signals analysis is an effective method to monitor the fluidized state on-line in the coating process at high temperature up to 1600 °C.

Thermal performance of glass fiber reinforced intumescent fire retardant coating for structural applications

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Faiz, E-mail: faizahmad@petronas.com.my; Ullah, Sami; Aziz, Hammad, E-mail: engr.hammad.aziz03@gmail.com; Omar, Nor Sharifah [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh 31750 Perak (Malaysia)

2015-07-22

The results of influence of glass fiber addition into the basic intumescent coating formulation towards the enhancement of its thermal insulation properties are presented. The intumescent coatings were formulated from expandable graphite, ammonium polyphosphate, melamine, boric acid, bisphenol A epoxy resin BE-188, polyamide amine H-2310 hardener and fiberglass (FG) of length 3.0 mm. Eight intumescent formulations were developed and the samples were tested for their fire performance by burning them at 450°C, 650°C and 850°C in the furnace for two hours. The effects of each fire test at different temperatures; low and high temperature were evaluated. Scanning Electron Microscope, X-Ray Diffraction technique and Thermo Gravimetric Analysis were conducted on the samples to study the morphology, the chemical components of char and the residual weight of the coatings. The formulation, FG08 containing 7.0 wt% glass fiber provided better results with enhanced thermal insulation properties of the coatings.

Corrosion Protection Performance of Polyester-Melamine Coating with Natural Wood Fiber Using EIS Analysis

Energy Technology Data Exchange (ETDEWEB)

Shin, PyongHwa; Shon, MinYoung [Pukyong National University, Busan (Korea, Republic of); Jo, DuHwan [POSCO, Gwangyang (Korea, Republic of)

2016-04-15

In the present study, polyester-melamine coating systems with natural wood fiber (NWF) were prepared and the effects of NWF on the corrosion protectiveness of the polyester-melamine coating were examined using EIS analysis. From the results, higher average surface roughness was observed with increase of NWF content. Water diffusivity and water uptake into the polyester-melamine coatings with NWF were much higher than that into the pure polyester-melamine coating. The decrease in the impedance modulus |Z| was associated with the localized corrosion on carbon steel, confirming that corrosion protection of the polyester-melamine coatings with NWF well agrees with its water transport behavior.

Analysis of irradiation-induced stresses in coating layers of coated fuel particles for the High Temperature Engineering Test Reactor (HTTR)

International Nuclear Information System (INIS)

Hayashi, Kimio; Kikuchi, Teruo; Fukuda, Kousaku; Sato, Sadao; Toyota, Junji; Shiozawa, Shusaku; Sawa, Kazuhiro; Kashimura, Satoru.

1991-07-01

Irradiation-induced stresses in coating layers of coated fuel particles were analyzed by the MICROS-2 code for the fuels of the High Temperature Engineering Test Reactor (HTTR) under its operating conditions. The analyses were made on the standard core fuel (A-type) and the test fuels comprising the advanced SiC-coated particle fuel (B-1 type) and the ZrC-coated particle fuel (B-2 type). For the B-1 type fuel, the stresses were relieved due to the thicker buffer and SiC layers than for the A type fuel. The slightly decreased thickness of the fourth layer for the B-1 type than for the A type fuel had no significant effect on the stresses. As for the B-2 type fuel, almost the same results as for the B-1 type were obtained under an assumption that the ZrC layer as well as the SiC layer undergoes negligible dimension change within the analysis conditions. The obtained results indicated that the B-1 and B-2 type fuels are better than the A type fuel in terms of integrity against the irradiation-induced stresses. Finally, research subjects for development of the analysis code on the fuel behavior are discussed. (author)

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

Tensile toughness test and high temperature fracture analysis of thermal barrier coatings

International Nuclear Information System (INIS)

Qian, G.; Nakamura, T.; Berndt, C.C.; Leigh, S.H.

1997-01-01

In this paper, an effective fracture toughness test which uses interface fracture mechanics theory is introduced. This method is ideally suited for determining fracture resistance of multilayered thermal barrier coatings (TBCs) consisting of ceramic and bond layers and, unlike other fracture experiments, requires minimal set-up over a simple tensile adhesion test. Furthermore, while other test methods usually use edge cracked specimens, the present test models a crack embedded within the coatings, which is more consistent with actual TBCs where failure initiates from internal voids or defects. The results of combined computational and experimental analysis show that any defects located within the ceramic coating can significantly weaken a TBC, whereas the debonding resistances of the bond coating and its interfaces are found to be much higher. In a separate analysis, the authors have studied fracture behavior of TBCs subjected to thermal loading in a high temperature environment. The computed fracture parameters reveal that when the embedded crack size is on order of the coating thickness, the fracture driving force is comparable to the fracture resistance of the coating found in the toughness test. In addition, the major driving force for fracture derives from the thermal insulating effect across the crack faces rather than the mismatch in the coefficients of thermal expansion. The authors have also investigated the effects of functionally graded material (FGM) within TBCs and found its influences on the fracture parameters to be small. This result implies that the FGM may not contribute toward enhancing the fracture toughness of the TBCs considered here

Vacuum Plasma Spraying W-coated Reduced Activation Structural Steels for Fusion Plasma Facing Components

Energy Technology Data Exchange (ETDEWEB)

Noh, Sanghoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

Tungsten (W) and its alloys are considered as candidate materials for plasma facing materials of the first wall and diverter components in fusion reactor systems because of high sputtering resistance and low tritium retention in a fusion environment. Therefore, it is considered that the joining between W and reduced activation structural steels, and its evaluation, are critical issues for the development of fusion reactors. However, the joining between these materials is a very challenging process because of significant differences in their physical properties, particularly the mismatch of coefficients of thermal expansion (CTE). For instance, the CTE of pure W is known to be about 4.3Χ10{sup -6}K{sup -1}; however, that of martensitic steels reaches over three times, about 12-14Χ10{sup -6}K{sup -1} at room temperature even up to 373K. Nevertheless, several joining techniques have been developed for joining between W and structural steels, such as a vapor deposition method, brazing and diffusion bonding. Meanwhile, vacuum plasma spraying (VPS) is supposed to be one of the prospective methods to fabricate a sufficient W layer on the steel substrates because of the coating of a large area with a relatively high fabricating rate. In this study, the VPS method of W powders on reduced activation steels was employed, and its microstructure and hardness distribution were investigated. ODS ferritic steels and F82H steel were coated by VPS-W, and the microstructure and hardness distribution were investigated. A microstructure analysis revealed that pure W was successfully coated on steel substrates by the VPS process without an intermediate layer, in spite of a mismatch of the CTE between dissimilar materials. After neutron irradiation, irradiation hardening significantly occurred in the VPSW. However, the hardening of VPS-W was lesser than that of bulk W irradiated HFIR at 773K. Substrate materials, ODS ferritic steels, and F82H steel, did not show irradiation hardening

Structural coloration of chitosan coated cellulose fabrics by electrostatic self-assembled poly (styrene-methyl methacrylate-acrylic acid) photonic crystals.

Science.gov (United States)

Yavuz, Gönül; Zille, Andrea; Seventekin, Necdet; Souto, Antonio P

2018-08-01

The structural coloration of a chitosan-coated woven cotton fabric obtained by glutaraldehyde-stabilized deposition of electrostatic self-assembled monodisperse and spherically uniform (250 nm) poly (styrene-methyl methacrylate-acrylic acid) photonic crystal nanospheres (P(St-MMA-AA)) was investigated. Bright iridescent coatings displaying different colors in function of the viewing angle were obtained. The SEM, diffuse reflectance spectroscopy, TGA, DSC and FTIR analyses confirm the presence of structural color and the glutaraldehyde and chitosan ability to provide durable chemical bonding between cotton fabric and photonic crystal (PCs) coating with the highest degradation temperature and the lowest enthalpy. The coatings are characterized by a mixture of face-centered cubic and hexagonal close-packed arrays alternating random packing regions. For the first time a cost-efficient structural coloration with high washing and light fastness using self-assembled P(St-MMA-AA) photonic crystals was successfully developed onto woven cotton fabric using chitosan and/or glutaraldehyde as stabilizing agent opening new strategies for the development of dye-free coloration of textiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Error Analysis of Ceramographic Sample Preparation for Coating Thickness Measurement of Coated Fuel Particles

International Nuclear Information System (INIS)

Liu Xiaoxue; Li Ziqiang; Zhao Hongsheng; Zhang Kaihong; Tang Chunhe

2014-01-01

The thicknesses of four coatings of HTR coated fuel particle are very important parameters. It is indispensable to control the thickness of four coatings of coated fuel particles for the safety of HTR. A measurement method, ceramographic sample-microanalysis method, to analyze the thickness of coatings was developed. During the process of ceramographic sample-microanalysis, there are two main errors, including ceramographic sample preparation error and thickness measurement error. With the development of microscopic techniques, thickness measurement error can be easily controlled to meet the design requirements. While, due to the coated particles are spherical particles of different diameters ranged from 850 to 1000μm, the sample preparation process will introduce an error. And this error is different from one sample to another. It’s also different from one particle to another in the same sample. In this article, the error of the ceramographic sample preparation was calculated and analyzed. Results show that the error introduced by sample preparation is minor. The minor error of sample preparation guarantees the high accuracy of the mentioned method, which indicates this method is a proper method to measure the thickness of four coatings of coated particles. (author)

Glial cell adhesion and protein adsorption on SAM coated semiconductor and glass surfaces of a microfluidic structure

Science.gov (United States)

Sasaki, Darryl Y.; Cox, Jimmy D.; Follstaedt, Susan C.; Curry, Mark S.; Skirboll, Steven K.; Gourley, Paul L.

2001-05-01

The development of microsystems that merge biological materials with microfabricated structures is highly dependent on the successful interfacial interactions between these innately incompatible materials. Surface passivation of semiconductor and glass surfaces with thin organic films can attenuate the adhesion of proteins and cells that lead to biofilm formation and biofouling of fluidic structures. We have examined the adhesion of glial cells and serum albumin proteins to microfabricated glass and semiconductor surfaces coated with self-assembled monolayers of octadecyltrimethoxysilane and N-(triethoxysilylpropyl)-O- polyethylene oxide urethane, to evaluate the biocompatibility and surface passivation those coatings provide.

Influence of sodium silicate concentration on structural and tribological properties of microarc oxidation coatings on 2017A aluminum alloy substrate

International Nuclear Information System (INIS)

Polat, Aytekin; Makaraci, Murat; Usta, Metin

2010-01-01

In this paper, thick and hard oxide coatings resistant to wear were produced on 2017A-T6 Al alloy by the microarc oxidation (MAO) technique in an alkali electrolyte consisting of different sodium silicate concentrations (0-8 g/l). The coatings were characterized by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and surface profilometry. Microhardness, scratch adhesion and pin-on-disk sliding wear tests were also performed to evaluate the tribological properties of the coatings. The influence of sodium silicate concentration on the structural and tribological properties of the MAO coatings was discussed. Results reveal that increasing sodium silicate concentration from 0 to 8 g/l in the electrolyte caused an increase in the electrolyte conductivity (from 7.71 to 18.1 mS/cm) and a decrease in positive final voltage (from 627 to 590 V) in the MAO process. In response to the increase in sodium silicate concentration, the thickness, surface roughness (R a ) and critical load (L c ) corresponding to adhesive failure of the coatings were increased simultaneously from 74 to 144 μm, and 4.4 to 6.58 μm, and 127.76 to 198.54 N, respectively. At the same time, the phase structure and composition of the coatings also varied by the participation of silicate ions in the reactions and their incorporation into the coating structure. Moreover, it was observed that the coating formed in the low sodium silicate concentration (4 g/l) had higher surface hardness (2020 HV) and improved wear resistance than the one (1800 HV) formed in the high sodium silicate concentration (8 g/l). The coatings produced in three different electrolytic solutions provided an excellent wear resistance and a load carrying capacity compared to the uncoated aluminum alloy.

Biological effects of rAAV-caAlk2 coating on structural allograft healing

DEFF Research Database (Denmark)

Koefoed, Mette; Ito, Hiromu; Gromov, Kirill

2005-01-01

Structural bone allografts often fracture due to their lack of osteogenic and remodeling potential. To overcome these limitations, we utilized allografts coated with recombinant adeno-associated virus (rAAV) that mediate in vivo gene transfer. Using beta-galactosidase as a reporter gene, we show...

X-ray Diffraction Studies of the Structure and Thermochemistry of Alkaline-Earth Oxide-Coated Thermionic Cathodes

Science.gov (United States)

Karikari, E. K.; Bassey, E.; Wintucky, Edwin G.

1998-01-01

NASA LeRC has a broad, active cathode technology development program in which both experimental and theoretical studies are being employed to further development of thermionic cathodes for use as electron sources in vacuum devices for communications and other space applications. One important type of thermionic cathode under development is the alkaline-earth oxide-coated (BaO, SrO, CaO) cathode. Significant improvements in the emission characteristics of this cathode have been obtained through modification of the chemical composition and morphology of the oxide coating, with the best result thus far coming from the addition of In2O3 and Sc2O3. Whereas the In2O3 produces a finer, more uniform particle structure, the exact chemical state and role of the Sc2O3 in the emission enhancement is unknown. The purpose of this cooperative agreement is to combine the studies of the surface chemistry and electron emission at NASA LeRC of chemically modified oxide coatings with a study of the thermochemistry and crystal structure using X-ray diffraction equipment and expertise at Clark Atlanta University (CAU). The study at CAU is intended to provide the description and understanding of the structure and thermochemistry needed for further improvement and optimization of the modified coatings. A description of the experimental procedure, preliminary X-ray diffraction test results, together with the design of an ultrahigh vacuum chamber necessary for high temperature thermochemistry studies will be presented.

Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

Directory of Open Access Journals (Sweden)

Eitvydas GRUZDYS

2011-07-01

Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

Correlation of optical properties with the fractal microstructure of black molybdenum coatings

Energy Technology Data Exchange (ETDEWEB)

Barrera, Enrique; Gonzalez, Federico [Area de Energia, Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, Mexico, D.F. 09340 (Mexico); Rodriguez, Eduardo [Area de Computacion y Sistemas, Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, Mexico, D.F. 09340 (Mexico); Alvarez-Ramirez, Jose, E-mail: jjar@xanum.uam.mx [Area de Energia, Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, Mexico, D.F. 09340 (Mexico)

2010-01-01

Coating is commonly used for improving the optical properties of surfaces for solar collector applications. The coating morphology depends on the deposition conditions, and this determines the final optical characteristics. Coating morphologies are irregular and of fractal nature, so a suitable approach for its characterization should use methods borrowed from fractal analysis. The aim of this work is to study the fractal characteristics of black molybdenum coatings on copper and to relate the fractal parameters to the optical properties. To this end, coating surfaces were prepared via immersion in a solution of ammonium paramolybdate for different deposition periods. The fractal analysis was carried out for SEM and AFM images of the coating surface and the fractal properties were obtained with a recently developed high-dimensional extension of the well-known detrended fluctuation analysis (DFA). The most salient parameter drawn from the application of the DFA is the Hurst index, a parameter related to the roughness of the coating surface, and the multifractality index, which is related to the non-linearity features of the coating morphology. The results showed that optical properties, including absorptance and emittance, are decreasing functions of the Hurst and multifractality indices. This suggests that coating surfaces with high absorptance and emittance values are related to complex coating morphologies conformed within a non-linear structure.

Novel Thiol-Ene Hybrid Coating for Metal Protection

Directory of Open Access Journals (Sweden)

Mona Taghavikish

2016-04-01

Full Text Available A novel hybrid anticorrosion coating with dual network of inorganic (Si–O–Si and organic bonds (C–S–C was prepared on metal through an in situ sol-gel and thiol-ene click reaction. This novel interfacial thin film coating incorporates (3-mercaptopropyl trimethoxysilane (MPTS and 1,4-di(vinylimidazolium butane bisbromide based polymerizable ionic liquid (PIL to form a thiol-ene based photo-polymerized film, which on subsequent sol-gel reaction forms a thin hybrid interfacial layer on metal surface. On top of this PIL hybrid film, a self-assembled nanophase particle (SNAP coating was employed to prepare a multilayer thin film coating for better corrosion protection and barrier performance. The novel PIL hybrid film was characterised for structure and properties using Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, and thermogravimetric analysis (TGA. The corrosion protection performance of the multilayer coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. The results reveal that this novel double layer coating on metal offers excellent protection against corrosion and has remarkably improved the barrier effect of the coating.

Thermal-Fatigue Analysis of W-coated Ferritic-Martensitic Steel Mockup for Fusion Reactor Components

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Won; Kim, Suk Kwon; Park, Seong Dae; Kim, Dong Jun [KAERI, Daejeon (Korea, Republic of); Moon, Se Yeon; Hong, Bong Guen [Chonbuk University, Jeonju (Korea, Republic of)

2016-05-15

In this study, commercial ANSYS-CFX for thermalhydraulic analysis and ANSYS-mechanical for the thermo-mechanical analysis are used to evaluate the thermal-lifetime of the mockup to determine the test conditions. Also, the Korea Heat Load Test facility with an Electron Beam (KoHLT-EB) will be used and its water cooling system is considered to perform the thermal-hydraulic analysis especially for considering the two-phase analysis with a higher heat flux conditions. Through the ITER blanket first wall (BFW) development project in Korea, the joining methods were developed with a beryllium (Be) layer as a plasma-facing material, a copper alloy (CuCrZr) layer as a heat sink, and type 316L austenitic stainless steel (SS316L) as a structural material. And joining methods were developed such as Be as an armor and FMS as a structural material, or W as an armor and FMS as a structural material were developed through the test blanket module (TBM) program. As a candidate of PFC for DEMO, a new W/FMS joining methods, W coating with plasma torch, have been developed. The HHF test conditions are found by performing a thermal-hydraulic and thermo-mechanical analysis with the conventional codes such as ANSYSCFX and .mechanical especially for considering the two-phase condition in cooling tube.

Structural evolution of plasma-sprayed nanoscale 3 mol% and 5 mol% yttria-stabilized zirconia coatings during sintering

Science.gov (United States)

Zhao, Yan; Gao, Yang

2017-12-01

The microstructure of plasma-sprayed nanostructured yttria-stabilized zirconia (YSZ) coatings may change during high-temperature exposure, which would influence the coating performance and service lifetime. In this study, the phase structure and the microstructural evolution of 3YSZ (zirconia-3 mol% yttria) and 5YSZ (zirconia-5 mol% yttria) nanostructured coatings were investigated by means of sintering at 1400 °C for 50-100 h. The microhardness, elastic moduli, and thermal shock cycles of the 3YSZ and 5YSZ nanostructured coatings were also investigated. The results showed that the redistribution of yttrium ions at 1400 °C caused the continuous increase of monoclinic-phase zirconia, but no obvious inter-splat cracking formed at the cross-sections, even after 100 h. Large voids appeared around the nanoporous zone because of the sintering of nanoscale granules upon high-temperature exposure. The microhardness and elastic moduli of the nanostructured coatings first increased and then decreased with increasing sintering times. The growth rate of the nanograins in the 3YSZ coating was lower than that in 5YSZ, which slowed the changes in 3YSZ coating porosity during sintering. Although the 3YSZ coating was prone to monoclinic phase transition, the experimental results showed that the thermal shock resistance of the 3YSZ coating was better than that of the 5YSZ coating.

Nano-enabled tribological thin film coatings: global patent scenario.

Science.gov (United States)

Sivudu, Kurva S; Mahajan, Yashwant R; Joshi, Shrikant V

2014-01-01

The aim of this paper is to present current status and future prospects of nano-enabled tribological thin film coatings based on worldwide patent landscape analysis. The study also presents an overview of technological trends by carrying out state-of-the-art literature analysis, including survey of corporate websites. Nanostructured tribological coatings encompass a wide spectrum of nanoscale microstructures, including nanocrystalline, nanolayered, nano-multilayered, nanocomposite, nanogradient structures or their unique combinations, which are composed of single or multi-component phases. The distinct microstructural features of the coatings impart outstanding tribological properties combined with multifunctional attributes to the coated components. Their unique combination of remarkable properties make them ideal candidates for a wide range of applications in diverse fields such as cutting and metalworking tools, biomedical devices, automotive engine components, wear parts, hard disc drives etc. The patent landscape analysis has revealed that nano-enabled tribological thin film coatings have significant potential for commercial applications in view of the lion's share of corporate industry in patenting activity. The largest patent portfolio is held by Japan followed by USA, Germany, Sweden and China. The prominent players involved in this field are Mitsubishi Materials Corp., Sandvik Aktiebolag, Hitachi Ltd., Sumitomo Electric Industries Ltd., OC Oerlikon Corp., and so on. The outstanding potential of nanostructured thin film tribological coatings is yet to be fully unravelled and, therefore, immense opportunities are available in future for microstructurally engineered novel coatings to enhance their performance and functionality by many folds.

Demonstration and Validation of Two Coat High Performance Coating System for Steel Structures in Corrosive Environments

Science.gov (United States)

2016-12-01

Many of these steel buildings and equipment are tradi- tionally painted with an alkyd enamel or waterborne coating for a top coat. These paint systems...bridging minor cracks or for surfaces that have vi- bration and/or movement. These qualities are necessary in a barrier coat- ing primer for it to remain

Analysis of Electrochemical Porosity of Phosphatized Coatings on Galvanized Steel Substrate

Directory of Open Access Journals (Sweden)

Ponte Haroldo de Araújo

2002-01-01

Full Text Available This work refers to the application of a Voltammetric Anodic Dissolution (VAD Technique in the analysis of coating discontinuities, focusing on pores and cracks that exposed the substrate. An evaluation was made of the influence of several parameters, such as the concentration of the passivation solution and sweep rate (SR, on the substrate passivation process and on the porosity indexes of tricationic phosphate coatings of Fe/Zn/Mn. The phosphatization process used was a commercial tricationic Fe/Zn/Mn phosphate bath applied on a galvanized steel (GS substrate. Once the best experimental conditions for the use of the VAD technique had been defined, the grain size and layer weight were related to porosity indexes. The porosity was found to show a tendency to decrease with increasing grain size. The VAD technique consists of the anodic polarization of the substrate/coating system and measurement of the charge density involved in the substrate passivation process. A quantitative porosity index was obtained by comparing the passivation charge density of the substrate without coating (standard passivation charge density and the passivation charge of the coated substrate.

Chemical bath deposited and dip coating deposited CuS thin films - Structure, Raman spectroscopy and surface study

Science.gov (United States)

Tailor, Jiten P.; Khimani, Ankurkumar J.; Chaki, Sunil H.

2018-05-01

The crystal structure, Raman spectroscopy and surface microtopography study on as-deposited CuS thin films were carried out. Thin films deposited by two techniques of solution growth were studied. The thin films used in the present study were deposited by chemical bath deposition (CBD) and dip coating deposition techniques. The X-ray diffraction (XRD) analysis of both the as-deposited thin films showed that both the films possess covellite phase of CuS and hexagonal unit cell structure. The determined lattice parameters of both the films are in agreement with the standard JCPDS as well as reported data. The crystallite size determined by Scherrer's equation and Hall-Williamsons relation using XRD data for both the as-deposited thin films showed that the respective values were in agreement with each other. The ambient Raman spectroscopy of both the as-deposited thin films showed major emission peaks at 474 cm-1 and a minor emmision peaks at 265 cm-1. The observed Raman peaks matched with the covellite phase of CuS. The atomic force microscopy of both the as-deposited thin films surfaces showed dip coating thin film to be less rough compared to CBD deposited thin film. All the obtained results are presented and deliberated in details.

Quantitative analysis of thermal insulation coatings

DEFF Research Database (Denmark)

Kiil, Søren

2014-01-01

This work concerns the development of simulation tools for mapping of insulation properties of thermal insulation coatings based on selected functional filler materials. A mathematical model, which includes the underlying physics (i.e. thermal conductivity of a heterogeneous two-component coating...

Contrasting evolutionary patterns of spore coat proteins in two Bacillus species groups are linked to a difference in cellular structure

Science.gov (United States)

2013-01-01

Background The Bacillus subtilis-group and the Bacillus cereus-group are two well-studied groups of species in the genus Bacillus. Bacteria in this genus can produce a highly resistant cell type, the spore, which is encased in a complex protective protein shell called the coat. Spores in the B. cereus-group contain an additional outer layer, the exosporium, which encircles the coat. The coat in B. subtilis spores possesses inner and outer layers. The aim of this study is to investigate whether differences in the spore structures influenced the divergence of the coat protein genes during the evolution of these two Bacillus species groups. Results We designed and implemented a computational framework to compare the evolutionary histories of coat proteins. We curated a list of B. subtilis coat proteins and identified their orthologs in 11 Bacillus species based on phylogenetic congruence. Phylogenetic profiles of these coat proteins show that they can be divided into conserved and labile ones. Coat proteins comprising the B. subtilis inner coat are significantly more conserved than those comprising the outer coat. We then performed genome-wide comparisons of the nonsynonymous/synonymous substitution rate ratio, dN/dS, and found contrasting patterns: Coat proteins have significantly higher dN/dS in the B. subtilis-group genomes, but not in the B. cereus-group genomes. We further corroborated this contrast by examining changes of dN/dS within gene trees, and found that some coat protein gene trees have significantly different dN/dS between the B subtilis-clade and the B. cereus-clade. Conclusions Coat proteins in the B. subtilis- and B. cereus-group species are under contrasting selective pressures. We speculate that the absence of the exosporium in the B. subtilis spore coat effectively lifted a structural constraint that has led to relaxed negative selection pressure on the outer coat. PMID:24283940

Metallic amorphous electrodeposited molybdenum coating from aqueous electrolyte: Structural, electrical and morphological properties under current density

Energy Technology Data Exchange (ETDEWEB)

Nemla, Fatima [LEPCM, Department of Physics, University of Batna (Algeria); Cherrad, Djellal, E-mail: cherradphisic@yahoo.fr [Laboratory for Developing New Materials and Their Characterizations, University of Setif (Algeria)

2016-07-01

Graphical abstract: - Highlights: • Although difficulties related to electrodeposition of Mo films, we have successfully coated onto a cooper substrate. • A good formation of bcc Mo phase and lattice parameter was very accurate. • It seems that electrical properties of our samples are good and suitable as back contact for thin film solar cells. • It seems that grain size, microstrain and dislocation density are all managed and correlated to retain the resistivity to a considerable minimum value. - Abstract: Molybdenum coatings are extensively utilized as back contact for CIGS-based solar cells. However, their electrodeposition from aqueous electrolyte still sophisticates, since long time, owing to the high reactivity with oxygen. In this study, we present a successful 30 min electrodeposition experiment of somewhat thick (∼0.98–2.9 μm) and of moderate surface roughness RMS (∼47–58 nm), metallic bright Mo coating from aqueous electrolyte containing molybdate ions. XRD analysis and Hall Effect measurements have been used to confirm the presence of Mo. The crystal structure of deposits was slightly amorphous in nature to body centred cubic structure (bcc) Mo (110), (211) and (220) face. Lattice parameters exhibit some weak fluctuated tensile stress when compared to the reference lattice parameter. Additionally, our calculated lattice parameters are in good agreement with some previous works from literature. Discussions on the grain growth prove that they are constrained by grain boundary energy not the thickness effect. Further discussions were made on the electrical resistivity and surface morphology. Resonance scattering of Fermi electrons are expected to contribute towards the variation in the film resistivity through the carrier mobility limitation. However, studied samples might be qualified as candidates for solar cell application.

Doctor Blade-Coated Polymer Solar Cells

KAUST Repository

Cho, Nam Chul

2016-10-25

In this work, we report polymer solar cells based on blade-coated P3HT:PC71BM and PBDTTT-EFT:PC71BM bulk heterojunction photoactive layers. Enhanced power conversion efficiency of 2.75 (conventional structure) and 3.03% (inverted structure) with improved reproducibility was obtained from blade-coated P3HT:PC71BM solar cells, compared to spin-coated ones. Furthermore, by demonstrating 3.10% efficiency flexible solar cells using blade-coated PBDTTT-EFT:PC71BM films on the plastic substrates, we suggest the potential applicability of blade coating technique to the high throughput roll-to-roll fabrication systems.

Growth, structure, and tribological behavior of atomic layer-deposited tungsten disulphide solid lubricant coatings with applications to MEMS

International Nuclear Information System (INIS)

Scharf, T.W.; Prasad, S.V.; Dugger, M.T.; Kotula, P.G.; Goeke, R.S.; Grubbs, R.K.

2006-01-01

This paper describes the synthesis, structure, and tribological behavior of nanocomposite tungsten disulphide (WS 2 ) solid lubricant films grown by atomic layer deposition. A new catalytic route, incorporating a diethyl zinc catalyst, was established to promote the adsorption and growth of WS 2 . The films were grown down to 8 nm in thickness by sequential exposures of WF 6 and H 2 S gases in a viscous flow reactor on Si, SiO 2 , stainless steel, and polycrystalline Si and electroplated Ni microelectromechanical systems structures. Films were studied by cross-sectional transmission electron microscopy (XTEM) with Automated eXpert Spectral Image Analysis (AXSIA) software for X-ray spectral images and X-ray diffraction to determine the coating conformality and crystallinity. The coatings exhibited a hexagonal layered structure with predominant preferentially orientated (0 0 2) basal planes. Regardless of orientation to the substrate surface, these basal planes when sheared imparted low friction with a steady-state friction coefficient as low as 0.008 to 50,000 cycles in a dry nitrogen environment. The formation of smooth transfer films during wear provided low interfacial shear stresses during sliding thus achieving low friction and wear. The XTEM combined with AXSIA of the wear tracks identified this mechanism and the effects of vapor phase reaction by-product etching on insulating and native polycrystalline Si and Ni surfaces

Liquid Impact Erosion Mechanism and Theoretical Stress Analysis in TiN-Coated Turbine Blade

International Nuclear Information System (INIS)

Lee, M. K.; Kim, W. W.; Kim, S. J.; Rhee, C. K.; Kim, Y. S.

2000-01-01

Coating of TiN film was done by reactive magnetron sputter ion plating to improve the liquid impact erosion resistance of steam turbine blade materials, 12Cr steel and Stellite 6B, for nuclear power plant application. TiN coated blade materials were initially deformed with depressions due to plastic deformation of the ductile substrate. The increase in the curvature in the depressions induced stress concentration with increasing number of impacts, followed by circumferential fracture of the TiN coating due to the circular propagation of cracks. The liquid impact erosion resistance of the blade materials was greatly improved by TiN coating done with the optimum ion plating condition. Damage decreased with increasing TiN coating thickness. According to the theoretical analysis of stresses generated by liquid impact, TiN coating alleviated the impact stress of 12Cr steel and Stellite 6B due to stress attenuation and stress wave reactions such as reflection and transmission at the coating substrate interface

Preparation and Characterization of Pyrotechnics Binder-Coated Nano-Aluminum Composite Particles

Science.gov (United States)

Ye, Mingquan; Zhang, Shuting; Liu, Songsong; Han, Aijun; Chen, Xin

2017-07-01

The aim of this article is to protect the activity of nano-aluminum (Al) particles in solid rocket propellants and pyrotechnics. The morphology, structure, active aluminum content, and thermal and catalytic properties of the coated samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry-differential scanning calorimetry (TG-DSC), and oxidation-reduction titration methods. The results indicated that nano-Al particles could be effectively coated with phenolic resin (PF), fluororubber (Viton B), and shellac through a solvent/nonsolvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 5-15 nm. Analysis of the active Al content revealed that Viton B coating had a much better protective effect. The TG-DSC results showed that the energy amount and energy release rate of PF-, Viton B-, and shellac-coated Al particles were larger than those of the raw nano-Al particles. The catalytic effects of coated Al particles on the thermal decomposition of ammonium perchlorate (AP) were better than those of raw nano-Al particles, and the effect of shellac-coated Al particles was significantly better than that of Viton B-coated Al particles.

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.

Structural Modification of Egyptian Kaolinite for Paper Coating

International Nuclear Information System (INIS)

Mohamed, H.F.; Hassan, M.S.; Morsy, F.A.; El-Sherbiny, S.

2013-01-01

The aim of this work is surface modification of Egyptian kaolinite for paper coating. Kaolinite < 2 fraction (KF) obtained using sedimentation and centrifuging techniques. Organo-kaolinite was prepared via inserting Urea (NH 2 CO NH 2 ) within the gallery of kaolinite using grinding technique for different times. Nano kaolinite was prepared from dispersion of organo-kaolinite in paper coating. The kaolinite (K), kaolinite /urea (KU) and kaolinite urea with binder (KU/Binder) were characterized using X-ray diffractometry (XRD), Infrared spectroscopy (IR) and Scanning Electron Microscopy (SEM). XRD studies revealed shifting of basal space of kaolinite from 0.714 to 1.11 nm upon grinding of kaolinite with urea for 5 h. On the other hand, the characteristic peak of kaolinite completely disappeared during dispersion of KU in paper coating suspension, which revealed the exfoliation of organo-kaolinite layers through the binder. Meanwhile, IR spectra show that NH-CO molecule exists in the intercalated kaolinite. The SEM images of KU revealed that kaolinite is intercalated U and fully exfoliation of KU achieved in KU/Binder and revealed by thin flakes with particle size ranged from 500 nm and 300 nm respectively. The modified kaolinite for paper coating increased the optical properties in terms of ISO brightness, opacity and gloss of the coated paper. There was a significant decrease in coated paper roughness compared to untreated kaolinite. Air permeance of the KF decreased in comparison with K sample, but increased sharply by intercalation of kaolinite (KU). Burst strength also started to increase with untreated kaolinite but decreased sharply with urea KU.

High speed PVD thermal barrier coatings

Energy Technology Data Exchange (ETDEWEB)

Beele, W. [Sulzer Metco Coatings BV (Netherlands); Eschendorff, G. [Sulzer Metco Coatings BV (Netherlands); Eldim BV (Netherlands)

2006-07-15

The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

High speed PVD thermal barrier coatings

International Nuclear Information System (INIS)

Beele, W.; Eschendorff, G.

2006-01-01

The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Calcium phosphate coatings modified with zinc- or copper- incorporation on Ti-40Nb alloy

Science.gov (United States)

Komarova, E. G.; Sedelnikova, M. B.; Sharkeev, Yu P.; Kazakbaeva, A. A.; Glukhov, I. A.; Khimich, M. A.

2017-05-01

The influence of the microarc oxidation parameters and electrolyte composition on the structure, properties and composition of CaP coatings modified with Zn- or Cu- incorporation on the Ti-40mas.%Nb (Ti-40Nb) alloy was investigated. The linear growth of thickness, roughness, and size of structural elements with process voltage increasing has been revealed. It was shown that the CaP coatings have the low contact angles with liquids and, consequently, high free surface energy. This indicates a high hydrophilicity of the coatings. X-ray diffraction analysis showed that the coatings have X-ray amorphous structure. The increase of the process voltage leads to the formation of such crystalline phases as CaHPO4 and β-Ca2P2O7 in the coatings. The maximum Ca/P atomic ratio was equal to 0.4, and Zn or Cu contents was equal to 0.3 or 0.2 at.%, respectively.

Spore coat protein of Bacillus subtilis. Structure and precursor synthesis.

Science.gov (United States)

Munoz, L; Sadaie, Y; Doi, R H

1978-10-10

The coat protein of Bacillus subtilis spores comprises about 10% of the total dry weight of spores and 25% of the total spore protein. One protein with a molecular weight of 13,000 to 15,000 comprises a major portion of the spore coat. This mature spore coat protein has histidine at its NH2 terminus and is relatively rich in hydrophobic amino acids. Netropsin, and antibiotic which binds to A-T-rich regions of DNA and inhibits sporulation, but not growth, decreased the synthesis of this spore coat protein by 75%. A precursor spore coat protein with a molecular weight of 25,000 is made initially at t1 of sporulation and is converted to the mature spore coat protein with a molecular weight of 13,500 at t2 - t3. These data indicate that the spore coat protein gene is expressed very early in sporulation prior to the modifications of RNA polymerase which have been noted.

Coating compositions comprising bismuth-alloyed zinc

DEFF Research Database (Denmark)

2008-01-01

The present application discloses (i) a coating composition comprising a particulate zinc-based alloyed material, said material comprising 0.05-0.7% by weight of bismuth (Bi), the D50 of the particulate material being in the range of 2.5-30 µm; (ii) a coated structure comprising a metal structure...... having a first coating of the zinc-containing coating composition applied onto at least a part of the metal structure in a dry film thickness of 5-100 µm; and an outer coating applied onto said zinc-containing coating in a dry film thickness of 30-200 µm; (iii) a particulate zinc-based alloyed material......, wherein the material comprises 0.05-0.7%(w/w) of bismuth (Bi), and wherein the D50 of the particulate material is in the range of 2.5-30 µm; (iv) a composite powder consisting of at least 25%(w/w) of the particulate zinc-based alloyed material, the rest being a particulate material consisting of zinc...

Cold-Sprayed AZ91D Coating and SiC/AZ91D Composite Coatings

Directory of Open Access Journals (Sweden)

Yingying Wang

2018-03-01

Full Text Available As an emerging coating building technique, cold spraying has many advantages to elaborate Mg alloy workpieces. In this study, AZ91D coatings and AZ91D-based composite coatings were deposited using cold spraying. Coatings were prepared using different gas temperatures to obtain the available main gas temperature. Compressed air was used as the accelerating gas, and although magnesium alloy is oxidation-sensitive, AZ91D coatings with good performance were obtained. The results show that dense coatings can be fabricated until the gas temperature is higher than 500 °C. The deposition efficiency increases greatly with the gas temperature, but it is lower than 10% for all coating specimens. To analyze the effects of compressed air on AZ91D powder particles and the effects of gas temperature on coatings, the phase composition, porosity, cross-sectional microstructure, and microhardness of coatings were characterized. X-ray diffraction and oxygen content analysis clarified that no phase transformation or oxidation occurred on AZ91D powder particles during cold spraying processes with compressed air. The porosity of AZ91D coatings remained between 3.6% and 3.9%. Impact melting was found on deformed AZ91D particles when the gas temperature increased to 550 °C. As-sprayed coatings exhibit much higher microhardness than as-casted bulk magnesium, demonstrating the dense structure of cold-sprayed coatings. To study the effects of ceramic particles on cold-sprayed AZ91D coatings, 15 vol % SiC powder particles were added into the feedstock powder. Lower SiC content in the coating than in the feedstock powder means that the deposition efficiency of the SiC powder particles is lower than the deposition efficiency of AZ91D particles. The addition of SiC particles reduces the porosity and increases the microhardness of cold-sprayed AZ91D coatings. The corrosion behavior of AZ91D coating and SiC reinforced AZ91D composite coating were examined. The Si

DETERMINATION OF PHASE COMPOSITION OF SEALING COATING BASED ON APC (ALUMINOPHOSPHATE COMPOUNDS

Directory of Open Access Journals (Sweden)

BOLSHAKOV V. I.

2017-02-01

Full Text Available Summary. Goal. To investigate the phase composition of the obtained sealing coatings based on aluminophosphate compound (APC and the impact of temperature rise on it. Methods. Qualitative X-ray phase analysis (XRPA and differential thermal analysis (DTA are used as the methods of research. Roentgenograms for structural analysis were obtained on a DRON-4-07 using filtered copper radiation in the secondary beam. Registration and initial processing of diffraction patterns was performed using the software package PDOS with the output of the diffraction patterns on the screen. Using the "loupe" option allowed to identify weak interference lines, which increased the accuracy of the method of qualitative XRPA. The thermograms for DTA received on the device type Termoskan-2. The results. It is revealed that base of coating is X-ray amorphous phase. There are following crystalline phases: Al, AlPO4, Al (PO3 3, BN found in the coating. It is revealed that annealing doesn’t make a significant influence on the phase composition of the crystalline phases and the coating doesn’t lose properties after annealing during repeated thermal stress. Scientific novelty. The phase composition of the proposed sealing coatings based on APC and produced by plasma spraying, and the effect of annealing on the phase composition of the coating are investigated. The reaction of synthesis of primary material forming on the basis of APC for coating is offered. Practical significance. The results can be used in aviation technology in the development of gas turbine engines (GTE and the design of the compressors. The sealing coating may be used to improve the reliability of the compressor and to increase the efficiency ratio of turbine engine. During the operation the compressor’s blades touch the sealing coating of compressor’s stator and grooves it without causing locking and destruction of the rotor. Therefore, the development of new sealing coating compositions that

Optimization of cardiovascular stent against restenosis: factorial design-based statistical analysis of polymer coating conditions.

Directory of Open Access Journals (Sweden)

Gayathri Acharya

Full Text Available The objective of this study was to optimize the physicodynamic conditions of polymeric system as a coating substrate for drug eluting stents against restenosis. As Nitric Oxide (NO has multifunctional activities, such as regulating blood flow and pressure, and influencing thrombus formation, a continuous and spatiotemporal delivery of NO loaded in the polymer based nanoparticles could be a viable option to reduce and prevent restenosis. To identify the most suitable carrier for S-Nitrosoglutathione (GSNO, a NO prodrug, stents were coated with various polymers, such as poly (lactic-co-glycolic acid (PLGA, polyethylene glycol (PEG and polycaprolactone (PCL, using solvent evaporation technique. Full factorial design was used to evaluate the effects of the formulation variables in polymer-based stent coatings on the GSNO release rate and weight loss rate. The least square regression model was used for data analysis in the optimization process. The polymer-coated stents were further assessed with Differential scanning calorimetry (DSC, Fourier transform infrared spectroscopy analysis (FTIR, Scanning electron microscopy (SEM images and platelet adhesion studies. Stents coated with PCL matrix displayed more sustained and controlled drug release profiles than those coated with PLGA and PEG. Stents coated with PCL matrix showed the least platelet adhesion rate. Subsequently, stents coated with PCL matrix were subjected to the further optimization processes for improvement of surface morphology and enhancement of the drug release duration. The results of this study demonstrated that PCL matrix containing GSNO is a promising system for stent surface coating against restenosis.

Development of a process for the removal of radioactively contaminated coatings from concrete and steel structures, when shutting down nuclear plant

International Nuclear Information System (INIS)

Klopfer, H.; Engelfried, R.; Ricken, D.; Schmidt, R.

1986-02-01

Considerable cooling (removal of heat) of materials leads to contractions and embrittlement. This permits a commutation of substances to be achieved. Through the application of very cold media on coated surfaces of concrete, screed, plaster and steel, such a considerable amount of heat is to be removed, that the arising inherent stresses lead to a separation of substrate in the coating. A carryout of radioactively contaminated components through arising primary and secondary waste must not occur here. Test specimens were produced with practical system structures, from substrate and coating. Using a specially constructed experimental plant, liquid nitrogen was applied to the coating surfaces. Under certain circumstances, it is possible to separate clods of coating from the substrate. Fine dusts or thaw water, which could cause a carryout of the radioactivity, were not observed. Application on an item, must be preceded by clarification of various influence, e.g. diffusion of stress in the compound system during nitrogen application, coating structure optimisation. (orig./HP) With 5 refs., 10 tabs., 25 figs [de

Comparative analysis of electrophysical properties of ceramic tantalum pentoxide coatings, deposited by electron beam evaporation and magnetron sputtering methods

Science.gov (United States)

Donkov, N.; Mateev, E.; Safonov, V.; Zykova, A.; Yakovin, S.; Kolesnikov, D.; Sudzhanskaya, I.; Goncharov, I.; Georgieva, V.

2014-12-01

Ta2O5 ceramic coatings have been deposited on glass substrates by e-beam evaporation and magnetron sputtering methods. For the magnetron sputtering process Ta target was used. X-ray diffraction measurements show that these coatings are amorphous. XPS survey spectra of the ceramic Ta2O5 coatings were obtained. All spectra consist of well-defined XPS lines of Ta 4f, 4d, 4p and 4s; O 1s; C 1s. Ta 4f doublets are typical for Ta2O5 coatings with two main peaks. Scanning electron microscopy and atomic force microscopy images of the e-beam evaporated and magnetron sputtered Ta2O5 ceramic coatings have revealed a relatively flat surface with no cracks. The dielectric properties of the tantalum pentoxide coatings have been investigated in the frequency range of 100 Hz to 1 MHz. The electrical behaviour of e-beam evaporated and magnetron sputtered Ta2O5 ceramic coatings have also been compared. The deposition process conditions principally effect the structure parameters and electrical properties of Ta2O5 ceramic coatings. The coatings deposited by different methods demonstrate the range of dielectric parameters due to the structural and stoichiometric composition changes

Acoustic Emission Analysis of Damage Progression in Thermal Barrier Coatings Under Thermal Cyclic Conditions

Science.gov (United States)

Appleby, Matthew; Zhu, Dongming; Morscher, Gregory

2015-01-01

Damage evolution of electron beam-physical vapor deposited (EBVD-PVD) ZrO2-7 wt.% Y2O3 thermal barrier coatings (TBCs) under thermal cyclic conditions was monitored using an acoustic emission (AE) technique. The coatings were heated using a laser heat flux technique that yields a high reproducibility in thermal loading. Along with AE, real-time thermal conductivity measurements were also taken using infrared thermography. Tests were performed on samples with induced stress concentrations, as well as calcium-magnesium-alumino-silicate (CMAS) exposure, for comparison of damage mechanisms and AE response to the baseline (as-produced) coating. Analysis of acoustic waveforms was used to investigate damage development by comparing when events occurred, AE event frequency, energy content and location. The test results have shown that AE accumulation correlates well with thermal conductivity changes and that AE waveform analysis could be a valuable tool for monitoring coating degradation and provide insight on specific damage mechanisms.

Damage-resistant brittle coatings

Energy Technology Data Exchange (ETDEWEB)

Lawn, B.R.; Lee, K.S. [National Inst. of Stand. and Technol., Gaithersburg, MD (United States). Mater. Sci. and Eng. Lab.; Chai, H. [Tel Aviv Univ. (Israel). Faculty of Engineering; Pajares, A. [Universidad de Extremadura, Badajoz (Spain). Dept. de Fisica; Kim, D.K. [Korea Advanced Inst. of Science and Technolgy, Taejon (Korea). Dept. of Materials Science and Engineering; Wuttiphan, S. [National Metal and Materials Technology Center, Bangkok (Thailand); Peterson, I.M. [Corning Inc., NY (United States); Hu Xiaozhi [Western Australia Univ., Nedlands, WA (Australia). Dept. of Mechanical and Materials Engineering

2000-11-01

Laminate structures consisting of hard, brittle coatings and soft, tough substrates are important in a wide variety of engineering applications, biological structures, and traditional pottery. In this study the authors introduce a new approach to the design of damage-resistant brittle coatings, based on a combination of new and existing relations for crack initiation in well-defined contact-induced stress fields. (orig.)

Can deformation of a polymer film with a rigid coating model geophysical processes?

Science.gov (United States)

Volynskii, A. L.; Bazhenov, S. L.

2007-12-01

The structural and mechanical behavior of polymer films with a thin rigid coating is analyzed. The behavior of such systems under applied stress is accompanied by the formation of a regular wavy surface relief and by regular fragmentation of the coating. The above phenomena are shown to be universal. Both phenomena (stress-induced development of a regular wavy surface relief and regular fragmentation of the coating) are provided by the specific features of mechanical stress transfer from a compliant soft support to a rigid thin coating. The above phenomena are associated with a specific structure of the system, which is referred to as “a rigid coating on a soft substratum” system (RCSS). Surface microrelief in RCSS systems is similar to the ocean floor relief in the vicinity of mid-oceanic ridges. Thus, the complex system composed of a young oceanic crust and upper Earth's mantle may be considered as typically “a solid coating on a soft substratum” system. Specific features of the ocean floor relief are analyzed in terms of the approach advanced for the description of the structural mechanical behavior of polymer films with a rigid coating. This analysis allowed to estimate the strength of an ocean floor.

The Effect of Cerium Ions on the Structure, Porosity and Electrochemical Properties of Si/Zr-Based Hybrid Sol-Gel Coatings Deposited on Aluminum

Directory of Open Access Journals (Sweden)

Peter Rodič

2018-04-01

Full Text Available This study was focused on the synthesis and characterization of Si/Zr-based hybrid sol-gel coatings with and without the addition of cerium(III ions. The coatings were deposited on aluminum aiming to act as an effective and ecologically harmless alternative to toxic chromate coatings. The chemical composition, structure, thermal properties and porosity of the non-doped and Ce-doped coatings containing various Zr contents were examined by Raman spectroscopy and photothermal beam deflection spectroscopy. The corrosion properties of the coated aluminum substrates were studied using AC and DC electrochemical methods in 0.1 M NaCl electrolyte solution. Barrier and protecting properties of the coatings were monitored upon long-term immersion in chloride solution using electrochemical impedance spectroscopy. The effect of cerium ions was two-fold: on the formation of a more condensed Si−O−Zr network structure and on the formation of Ce-based deposits, which diminish the rate of cathodic reaction at the coating/metal interface. These effects acted synergistically and resulted in the creation of the coatings with effective barrier and active corrosion protection.

Effect of Tungsten Nanolayer Coating on Si Electrode in Lithium-ion Battery

Science.gov (United States)

Son, Byung Dae; Lee, Jun Kyu; Yoon, Woo Young

2018-02-01

Tungsten (W) was coated onto a silicon (Si) anode at the nanoscale via the physical vaporization deposition method (PVD) to enhance its electrochemical properties. The characteristics of the electrode were identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis, and electron probe X-ray microanalysis. With the electrochemical property analysis, the first charge capacities of the W-coated and uncoated electrode cells were 2558 mAh g- 1 and 1912 mAh g- 1, respectively. By the 50th cycle, the capacity ratios were 61.1 and 25.5%, respectively. Morphology changes in the W-coated Si anode during cycling were observed using SEM and TEM, and electrochemical characteristics were examined through impedance analysis. Owing to its conductivity and mechanical properties from the atomic W layer coating through PVD, the electrode improved its cyclability and preserved its structure from volumetric demolition.

Optical Coating Performance and Thermal Structure Design for Heat Reflectors of JWST Electronic Control Unit

Science.gov (United States)

Quijada, Manuel A.; Threat, Felix; Garrison, Matt; Perrygo, Chuck; Bousquet, Robert; Rashford, Robert

2008-01-01

The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling system.

Analytical Modeling of Hard-Coating Cantilever Composite Plate considering the Material Nonlinearity of Hard Coating

Directory of Open Access Journals (Sweden)

Wei Sun

2015-01-01

Full Text Available Due to the material nonlinearity of hard coating, the coated structure produces the nonlinear dynamical behaviors of variable stiffness and damping, which make the modeling of hard-coating composite structure become a challenging task. In this study, the polynomial was adopted to characterize this material nonlinearity and an analytical modeling method was developed for the hard-coating composite plate. Firstly, to relate the hard-coating material parameters obtained by test and the analytical model, the expression of equivalent strain of composite plate was derived. Then, the analytical model of hard-coating composite plate was created by energy method considering the material nonlinearity of hard coating. Next, using the Newton-Raphson method to solve the vibration response and resonant frequencies of composite plate and a specific calculation procedure was also proposed. Finally, a cantilever plate coated with MgO + Al2O3 hard coating was chosen as study case; the vibration response and resonant frequencies of composite plate were calculated using the proposed method. The calculation results were compared with the experiment and general linear calculation, and the correctness of the created model was verified. The study shows the proposed method can still maintain an acceptable precision when the material nonlinearity of hard coating is stronger.

New method for characterizing paper coating structures using argon ion beam milling and field emission scanning electron microscopy.

Science.gov (United States)

Dahlström, C; Allem, R; Uesaka, T

2011-02-01

We have developed a new method for characterizing microstructures of paper coating using argon ion beam milling technique and field emission scanning electron microscopy. The combination of these two techniques produces extremely high-quality images with very few artefacts, which are particularly suited for quantitative analyses of coating structures. A new evaluation method has been developed by using marker-controlled watershed segmentation technique of the secondary electron images. The high-quality secondary electron images with well-defined pores makes it possible to use this semi-automatic segmentation method. One advantage of using secondary electron images instead of backscattered electron images is being able to avoid possible overestimation of the porosity because of the signal depth. A comparison was made between the new method and the conventional method using greyscale histogram thresholding of backscattered electron images. The results showed that the conventional method overestimated the pore area by 20% and detected around 5% more pores than the new method. As examples of the application of the new method, we have investigated the distributions of coating binders, and the relationship between local coating porosity and base sheet structures. The technique revealed, for the first time with direct evidence, the long-suspected coating non-uniformity, i.e. binder migration, and the correlation between coating porosity versus base sheet mass density, in a straightforward way. © 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.

Pedigree analysis in the Austrian Noriker draught horse: genetic diversity and the impact of breeding for coat colour on population structure.

Science.gov (United States)

Druml, T; Baumung, R; Sölkner, J

2009-10-01

The pedigree of the current Austrian Noriker draught horse population comprising 2808 horses was traced back to the animals considered as founders of this breed. In total, the number of founders was 1991, the maximum pedigree length was 31 generations, with an average of 12.3 complete generations. Population structure in this autochthonous Austrian draught horse breed is defined by seven breeding regions (Carinthia, Lower Austria, Salzburg, Styria, Tyrol, Upper Austria and Vorarlberg) or through six coat colour groups (Bay, Black, Chestnut, Roan, Leopard, Tobiano). Average inbreeding coefficients within the breeding regions ranged from 4.5% to 5.5%; for the colour groups, the coefficients varied from 3.5% to 5.9%. Other measures of genetic variability like the effective number of founders, ancestors and founder genomes revealed a slightly different genetic background of the subpopulations. Average co-ancestries between and within breeding areas showed that the Salzburg population may be considered as the nucleus or original stock whereas all other subpopulations showed high relationship to horses from Salzburg. The target of draught horse breeding in the 21st century does not meet the breeding concept of maximizing genetic gains any more. Stabilizing selection takes place. In this study, we show that demographic factors as well as structure given by different coat colours helped to maintain genetic diversity in this endangered horse breed.

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.

Electrophoretic deposition of hydroxyapatite-hexagonal boron nitride composite coatings on Ti substrate.

Science.gov (United States)

Göncü, Yapıncak; Geçgin, Merve; Bakan, Feray; Ay, Nuran

2017-10-01

In this study, commercial pure titanium samples were coated with nano hydroxyapatite-nano hexagonal boron nitride (nano HA-nano hBN) composite by electrophoretic deposition (EPD). The effect of process parameters (applied voltage, deposition time and solid concentration) on the coating morphology, thickness and the adhesion behavior were studied systematically and crack free nano hBN-nano HA composite coating production was achieved for developing bioactive coatings on titanium substrates for orthopedic applications. For the examination of structural and morphological characteristics of the coating surfaces, various complementary analysis methods were performed. For the structural characterization, XRD and Raman Spectroscopy were used while, Scanning Electron Microscopy (SEM) equipped with an energy dispersive spectrometer (EDS) and Transmission Electron Microscopy (TEM) techniques were carried out for revealing the morphological characterization. The results showed that nano HA-nano hBN were successfully deposited on Ti surface with uniform, crack-free coating by EPD. The amounts of hBN in suspension are considered to have no effect on coating thickness. By adding hBN into HA, the morphology of HA did not change and hBN has no significant effect on porous structure. These nanostructured surfaces are expected to be suitable for proliferation of cells and have high potential for bioactive materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Multispectral Image Analysis for Robust Prediction of Astaxanthin Coating

DEFF Research Database (Denmark)

Ljungqvist, Martin Georg; Frosch, Stina; Nielsen, Michael Engelbrecht

2013-01-01

The aim of this study was to investigate the possibility of predicting the type and concentration level of astaxanthin coating of aquaculture feed pellets using multispectral image analysis. We used both natural and synthetic astaxanthin, and we used several different concentration levels...... of synthetic astaxanthin in combination with four different recipes of feed pellets. We used a VideometerLab with 20 spectral bands in the range of 385-1050 nm. We used linear discriminant analysis and sparse linear discriminant analysis for classification and variable selection. We used partial least squares...

Transcriptome Analysis of a New Peanut Seed Coat Mutant for the Physiological Regulatory Mechanism Involved in Seed Coat Cracking and Pigmentation.

Science.gov (United States)

Wan, Liyun; Li, Bei; Pandey, Manish K; Wu, Yanshan; Lei, Yong; Yan, Liying; Dai, Xiaofeng; Jiang, Huifang; Zhang, Juncheng; Wei, Guo; Varshney, Rajeev K; Liao, Boshou

2016-01-01

Seed-coat cracking and undesirable color of seed coat highly affects external appearance and commercial value of peanuts ( Arachis hypogaea L.). With an objective to find genetic solution to the above problems, a peanut mutant with cracking and brown colored seed coat (testa) was identified from an EMS treated mutant population and designated as "peanut seed coat crack and brown color mutant line ( pscb )." The seed coat weight of the mutant was almost twice of the wild type, and the germination time was significantly shorter than wild type. Further, the mutant had lower level of lignin, anthocyanin, proanthocyanidin content, and highly increased level of melanin content as compared to wild type. Using RNA-Seq, we examined the seed coat transcriptome in three stages of seed development in the wild type and the pscb mutant. The RNA-Seq analysis revealed presence of highly differentially expressed phenylpropanoid and flavonoid pathway genes in all the three seed development stages, especially at 40 days after flowering (DAF40). Also, the expression of polyphenol oxidases and peroxidase were found to be activated significantly especially in the late seed developmental stage. The genome-wide comparative study of the expression profiles revealed 62 differentially expressed genes common across all the three stages. By analyzing the expression patterns and the sequences of the common differentially expressed genes of the three stages, three candidate genes namely c36498_g1 (CCoAOMT1), c40902_g2 (kinesin) , and c33560_g1 (MYB3) were identified responsible for seed-coat cracking and brown color phenotype. Therefore, this study not only provided candidate genes but also provided greater insights and molecular genetic control of peanut seed-coat cracking and color variation. The information generated in this study will facilitate further identification of causal gene and diagnostic markers for breeding improved peanut varieties with smooth and desirable seed coat color.

Nano-structured yttria-stabilized zirconia coating by electrophoretic deposition

Energy Technology Data Exchange (ETDEWEB)

Maleki-Ghaleh, H., E-mail: H_Maleki@sut.ac.ir [Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Rekabeslami, M. [Faculty of Mechanical Engineering, Materials Science and Engineering Division, K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Shakeri, M.S. [Materials and Energy Research Center, Karaj (Iran, Islamic Republic of); Siadati, M.H. [Faculty of Mechanical Engineering, Materials Science and Engineering Division, K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Javidi, M. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Talebian, S.H. [Faculty of Petroleum Engineering, Universiti Technologi Petronas, Perak (Malaysia); Aghajani, H. [Department of Materials Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2013-09-01

The most important role of thermal barrier coatings is to reduce the temperature of the substrate in high temperature applications. Nanoparticle zirconia might be a suitable choice for improving the efficiency of thermal barrier coatings. Nanostructured coatings have lower thermal conduction, higher thermal expansion and lower dimensional variations at higher temperatures in comparison with the microstructured coatings. Electrophoretic deposition has been preferred for thermal barrier coatings due to its simplicity, controllability and low cost. In the present study, three different suspensions of ZrO{sub 2}–8 wt%Y{sub 2}O{sub 3} (40 nm) made with ethanol, acetone and acetyl acetone were used. Electrophoretic deposition was conducted at a fixed voltage of 60 V for 120 s on aluminized Inconel 738-LC, and then heat treated at 1100{sup o}C for 4 h in air atmosphere. The coating morphology and elemental distribution were studied using scanning electron microscopy. It was observed that suspension media have an important effect on the quality of the final product. Acetyl acetone showed better dispersion of particles than the other two media. Consequently, deposition from acetyl acetone resulted in uniform and crack-free layers while those from ethanol and acetone were completely non-uniform due to agglomeration and low viscosity, respectively.

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.

Enhanced corrosion protective PANI-PAA/PEI multilayer composite coatings for 316SS by spin coating technique

Energy Technology Data Exchange (ETDEWEB)

Syed, Junaid Ali; Lu, Hongbin; Tang, Shaochun; Meng, Xiangkang, E-mail: mengxk@nju.edu.cn

2015-01-15

Highlights: • PANI-PAA/PEI multilayers with controllable thickness were fabricated by spin assembly. • PAA matrix results in the homogeneous dispersion of PANI in the composite coatings. • Spin coating combined with heating assures the linear increase in thickness with n. • The corrosion protection property of PANI-PAA/PEI coatings were optimized at n = 20. • Enhanced protection owing to multilayer structure that lengthens the diffusion pathway of ions. - Abstract: In the present study, polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) composite coatings with a multilayer structure for corrosion protection of 316 stainless steels (316SS) were prepared by an alternate deposition. Spin coating combined with heating assists removal of residual water that result in a linear increase in thickness with layer number (n). The combination of PANI-PAA composite with PEI and their multilayer structure provides a synergistic enhancement of corrosion resistance properties as determined by electrochemical measurements in 3.5% NaCl solution. Importantly, the PANI-PAA/PEI coating with an optimized layer number of n = 20 shows improved corrosion protection. The superior performance was attributed to the formation of an interfacial oxide layer as well as the multilayer structure that extend the diffusion pathway of corrosive ions.

Application of nano-structured coatings to mitigate flow-accelerated corrosion in secondary pipe systems of nuclear power plants

International Nuclear Information System (INIS)

Kim, Seung Hyun; Kim, Jong Jin; Yoo, Seung Chang; Kim, Ji Hyun

2014-01-01

Carbon steel is widely used as a structural material in secondary pipe systems. However, the passivity of carbon steel is not sufficient for protection in secondary water chemistry with a very fast-flowing fluid because of the dissolution of ferrous and magnetite ions and surface friction at the interface of the coolant and pipe surface. There have been many efforts to mitigate flow-accelerated corrosion through adoption of advanced water chemistries such as optimized dissolve oxygen (DO) concentration and temperature, as well as usage of new additives such as monoethanol amine (ETA) to adjust pH. However, these mitigation techniques pose certain challenges relating to the compatibility of new water chemistries with the steam generator, the thermal efficiency of the secondary side, etc. In this study, to improve the passivity of carbon steel, nanostructured coatings especially nanoparticle-enhanced surface coatings were adopted to improve resistance to corrosion and wear. Nanoparticles in the coating matrix help decrease the electrochemical potential compared coatings without nanoparticles, and thus help improve the mechanical properties, especially hardness, through precipitation. In other words, nanoparticle-enhanced surface coatings have the potential to mitigate flow-accelerated corrosion in secondary pipe systems. As candidate coatings, TiO 2 - and SiC-enhanced electrolytic and electroless nickel plating and Fe-Cr-W amorphous metallic coatings (AMC) were selected by acquiring the Pourbaix diagram with thermodynamic calculations. Both TiO 2 and SiC show a stable state in secondary water chemistry, and it is estimated that Fe-Cr-W can be applied to secondary water chemistry because it has a similar chemical composition to carbon steel. Electron microscopic analysis results with scanning electron microscopy (SEM) and tunneling electron microscopy (TEM) show the distribution of TiO 2 nanoparticles in the nickel matrix coating layer, whereas the SiC nanoparticles

Porous SiO_2 nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

International Nuclear Information System (INIS)

Das, Indranee; De, Goutam; Hupa, Leena; Vallittu, Pekka K.

2016-01-01

A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO_2 nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

Structural and optical characteristics of nano-sized structure of Zn0.5Cd0.5S thin films prepared by dip-coating method

International Nuclear Information System (INIS)

Rafea, M. Abdel; Farag, A.A.M.; Roushdy, N.

2009-01-01

In this work, a stoichiometry Zn 0.5 Cd 0.5 S nano-structured powder was synthesized. Thin films of different thicknesses of Zn 0.5 Cd 0.5 S were prepared by dip-coating method onto glass substrates. The X-ray diffraction analysis of the prepared powder and films were performed to investigate the crystalline structure. Some structural parameters such as the mean crystallite size and the internal lattice strain were calculated. The composition analysis was made by the energy dispersive X-ray technique, EDX. Scanning electron micrographs, SEM showed that the prepared films are nearly homogeneous and consists of nearly parallel surfaces and the thickness was determined by the cross section imaging. The transmission spectra, T(λ), of the films at normal incidence of light were obtained in the spectral region 190-1100 nm. The optical constants of Zn 0.5 Cd 0.5 S films were determined using the interference maxima and minima of the transmission spectrum. The dispersion of refractive index was discussed in terms of the single-oscillator model and the important oscillating parameters were determined. The dependence of absorption coefficient on the photon energy was determined and the analysis of the result showed that the optical transition in Zn 0.5 Cd 0.5 S is allowed and indirect. The thickness dependence of the obtained optical parameters was also considered.

Structural analysis of a coating of TiN over a Cu-Ti-Cr alloy: Study of the Cu-Ti interphase

International Nuclear Information System (INIS)

Villegas Vejar, C; Suazo, A; Radtk, H; Carrasco, C

2004-01-01

The crystalline structure of a thin film of TiN deposited by DC planar magnetron sputtering over a ternary copper alloy was studied. A fine film of titanium was deposited between the coating and the substrate for better adherence. The samples were analyzed with a transmission electron microscope to determine the structure of each of the components as well as the network distortion in the Cu-Ti interphase. The results were complemented with previous X-ray diffraction analyses to identify the network parameter for each of the study components and the respective residual tensions. This study shows the agreement between the network distortion and the residual tensions that were measured, and also relates the theory of crystalline coherence with the experimentally calculated break down by electron diffraction in the Cu-Ti interphase (CW)

Economic Analysis Of Radiation Surface Coating Of Parquet Flooring

International Nuclear Information System (INIS)

Danu, S.

1989-01-01

The surface coating of mosaic parquet flooring has been done using electron beam and UV irradiation in a pilot scale and technically successful. Economic analysis of the coating process will be discussed in this paper. Four kinds of irradiated parquet flooring were used for comparing costs and important factors on the analysis such as capital, production cost, selling price, break-event point, payout time and internal rate of return. The results showed there the higher quality of the products, the higher are its production cost and selling price. The selling price of irradiated parquet flooring per m2 for process A, B, C and D were Rp. 20,700; Rp. 23,900; Rp. 24,500; and Rp. 25,000 at the lowest profit level of 10% and RP. 25,500; Rp. 34,700; Rp. 35,500; and Rp. 36,400 at the highest profit level of 150% of the fixed capital. The total capital required were Rp. 1.9 billion up to 3.3 billion. (author). 5 refs, 9 tabs

Stability analysis of SiO2/SiC multilayer coatings

International Nuclear Information System (INIS)

Fu Zhiqiang; Jean-Charles, R.

2006-01-01

The stability behaviours of SiC coatings and SiO 2 /SiC coatings in helium with little impurities are studied by HSC Chemistry 4.1, the software for analysis of Chemical reaction and equilibrium in multi-component complex system. It is found that in helium with a low partial pressure of oxidative impurities under different total pressure, the key influence factor controlling T cp of SiC depends is the partial pressure of oxidative impurities; T cp of SiC increases with the partial pressure of oxidative impurities. In helium with a low partial pressure of different impurities, the key influence factor of T cs of SiO 2 are both the partial pressure of impurities and the amount of impurities for l mol SiO 2 ; T cs of SiO 2 increases with the partial pressure of oxidative impurities at the same amount of the impurities for 1 mol SiO 2 while it decreases with the amount of the impurities for 1 mm SiO 2 at the same partial pressure of the impurities. The influence of other impurities on T cp of SiC in He-O 2 is studied and it is found that CO 2 , H 2 O and N-2 increase T cp of SiC in He-O 2 while H 2 , CO and CH 4 decrease T cp of SiC He-O 2 . When there exist both oxidative impurities and reductive impurities, their effect on T cs of SiO 2 can be suppressed by the other. In HTR-10 operation atmosphere, SiO 2 /SiC coatings can keep stable status at higher temperature than SiC coatings, so SiO 2 /SiC coatings is more suitable to improve the oxidation resistance of graphite in HTR-10 operation atmosphere compared with SiC coatings. (authors)

Physicochemical and Biological Investigation of Different Structures of Carbon Coatings Deposited onto Polyurethane

Directory of Open Access Journals (Sweden)

Witold Kaczorowski

2016-01-01

Full Text Available The aim of this study was to examine the thrombogenic properties of polyurethane that was surface modified with carbon coatings. Physicochemical properties of manufactured coatings were investigated using transmission electron microscopy (TEM, atomic force microscopy (AFM, X-ray Photoelectron Spectroscopy (XPS, Raman spectroscopy and contact angle measurement methods. Samples were examined by the Impact-R method evaluating the level of platelets activation and adhesion of particular blood cell elements. The analysis of antimicrobial resistance against E. coli colonization and viability of endothelial cells showed that polyurethane modified with use of carbon layers constituted an interesting solution for biomedical application.

Hydroxyapatite coatings for biomedical applications

CERN Document Server

Zhang, Sam

2013-01-01

Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characteri

Isothermal and dynamic oxidation behaviour of Mo-W doped carbon-based coating

Science.gov (United States)

Mandal, Paranjayee; Ehiasarian, Arutiun P.; Hovsepian, Papken Eh.

2015-10-01

The oxidation behaviour of Mo-W doped carbon-based coating (Mo-W-C) is investigated in elevated temperature (400-1000 °C). Strong metallurgical bond between Mo-W-C coating and substrate prevents any sort of delamination during heat-treatment. Isothermal oxidation tests show initial growth of metal oxides at 500 °C, however graphitic nature of the as-deposited coating is preserved. The oxidation progresses with further rise in temperature and the substrate is eventually exposed at 700 °C. The performance of Mo-W-C coating is compared with a state-of-the-art DLC(Cr/Cr-WC/W:C-H/a:C-H) coating, which shows preliminary oxidation at 400 °C and local delamination of the coating at 500 °C leading to substrate exposure. The graphitisation starts at 400 °C and the diamond-like structure is completely converted into the graphite-like structure at 500 °C. Dynamic oxidation behaviour of both the coatings is investigated using Thermo-gravimetric analysis carried out with a slow heating rate of 1 °C/min from ambient temperature to 1000 °C. Mo-W-C coating resists oxidation up to ˜800 °C whereas delamination of DLC(Cr/Cr-WC/W:C-H/a:C-H) coating is observed beyond ˜380 °C. In summary, Mo-W-C coating provides improved oxidation resistance at elevated temperature compared to DLC(Cr/Cr-WC/W:C-H/a:C-H) coating.

Stress Analysis of a TRISO Coated Particle Fuel by Using ABAQUS Finite Element Visco-Elastoplastic Solutions

International Nuclear Information System (INIS)

Cho, Moon Sung; Kim, Y. M.; Lee, Y. W.

2006-01-01

The fundamental design for a gas-cooled reactor relies on an understanding of the behavior of a coated particle fuel. KAERI, which has been carrying out the Korean VHTR (Very High Temperature modular gas cooled Reactor) Project since 2004, is developing a fuel performance analysis code for a VHTR named COPA (COated Particle fuel Analysis). A validation of COPA was attempted by comparing its benchmark results with the visco-elastic solutions obtained from the ABAQUS code calculations for the IAEA-CRP-6 TRISO coated particle benchmark problems involving a creep, swelling, and pressure. However, the ABAQUS finite element model used for the above-mentioned analysis did not consider the material nonlinearity of the SiC coating layer that showed stress levels higher than the assumed yield point of the material. In this study, a consideration of the material nonlinearity is included in the ABAQUS model to obtain the visco-elastoplastic solutions and the results are compared with the visco-elastic solutions obtained from the previous ABAQUS model

Structure and properties of a duplex coating combining micro-arc oxidation and baking layer on AZ91D Mg alloy

Science.gov (United States)

Cui, Xue-Jun; Li, Ming-Tian; Yang, Rui-Song; Yu, Zu-Xiao

2016-02-01

A duplex coating (called MAOB coating) was fabricated on AZ91D Mg alloy by combining the process of micro-arc oxidation (MAO) with baking coating (B-coating). The structure, composition, corrosion resistance, and tribological behaviour of the coatings were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrochemical and long-term immersion test, and ball-on-disc friction test. The results show that a dense 92 μm thick B-coating was tightly deposited onto the MAO-coated Mg alloy and exhibited a good mechanical interlock along the rough interface. Compared with the MAO-coated sample, the corrosion current density of the MAOB-coated Mg alloy decreased by two or three orders of magnitude and no corrosion phenomenon was observed during a long-term immersion test of about 500 h (severe corrosion pits were found for MAO-treated samples after about 168 h of immersion). The frictional coefficient values of the MAOB coating were similar to those of the MAO coating using dry sliding tests, while the B-coating on the MAO-coated surface significantly improved the wear resistance of the AZ91D Mg alloy. All of these results indicate that a B-coating can be used to further protect Mg alloys from corrosion and wear by providing a thick, dense barrier.

Ductile electroless Ni-P coating onto flexible printed circuit board

Science.gov (United States)

Wang, Wenchang; Zhang, Weiwei; Wang, Yurong; Mitsuzak, Naotoshi; Chen, Zhidong

2016-03-01

In this study, a ductile electroless Ni-P coating on the flexible printed circuit board (FPCB) was prepared in an acidic nickel plating bath. The addition of dipropylamine (DPA) in electroless plating not only improves the ductility of the Ni-P coating, but also enhances the corrosion resistance. The further analysis reveals that the ductility improvement and enhancement of corrosion resistance for the Ni-P coating may be due to the fact that the addition of DPA significantly refines the volume of columnar nodule and reduce the porosity, thus leading to the released internal stress. In addition, it was found that the nodule within the Ni-P coating grew into a columnar structure, which may be also contribute to the improvement of ductility.

Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

International Nuclear Information System (INIS)

Asoh, Hidetaka; Uchibori, Kota; Ono, Sachiko

2009-01-01

The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

Structural features of anodic oxide films formed on aluminum substrate coated with self-assembled microspheres

Energy Technology Data Exchange (ETDEWEB)

Asoh, Hidetaka [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)], E-mail: asoh@cc.kogakuin.ac.jp; Uchibori, Kota; Ono, Sachiko [Department of Applied Chemistry, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 (Japan)

2009-07-15

The structural features of anodic oxide films formed on an aluminum substrate coated with self-assembled microspheres were investigated by scanning electron microscopy and atomic force microscopy. In the first anodization in neutral solution, the growth of a barrier-type film was partially suppressed in the contact area between the spheres and the underlying aluminum substrate, resulting in the formation of ordered dimple arrays in an anodic oxide film. After the subsequent second anodization in acid solution at a voltage lower than that of the first anodization, nanopores were generated only within each dimple. The nanoporous region could be removed selectively by post-chemical etching using the difference in structural dimensions between the porous region and the surrounding barrier region. The mechanism of anodic oxide growth on the aluminum substrate coated with microspheres through multistep anodization is discussed.

Carbon nanotube based functional superhydrophobic coatings

Science.gov (United States)

Sethi, Sunny

The main objective of this dissertation is synthesis of carbon nanotube (CNT) based superhydrophobic materials. The materials were designed such that electrical and mechanical properties of CNTs could be combined with superhydrophobicity to create materials with unique properties, such as self-cleaning adhesives, miniature flotation devices, ice-repellant coatings, and coatings for heat transfer furnaces. The coatings were divided into two broad categories based on CNT structure: Vertically aligned CNT arrays (VA coatings) and mesh-like (non-aligned) carbon nanotube arrays (NA coatings). VA coatings were used to create self-cleaning adhesives and flexible field emission devices. Coatings with self cleaning property along with high adhesiveness were inspired from structure found on gecko foot. Gecko foot is covered with thousands of microscopic hairs called setae; these setae are further divided into hundreds of nanometer sized hairs called spatulas. When gecko presses its foot against any surface, these hairs bend and conform to the topology of the surface resulting into very large area of contact. Such large area of intimate contact allows geckos to adhere to surfaces using van der Waals (vdW) interactions alone. VA-CNTs adhere to a variety of surfaces using a similar mechanism. CNTs of suitable diameter could withstand four times higher adhesion force than gecko foot. We found that upon soiling these CNT based adhesives (gecko tape) could be cleaned using a water droplet (lotus effect) or by applying vibrations. These materials could be used for applications requiring reversible adhesion. VA coatings were also used for developing field emission devices. A single CNT can emit electrons at very low threshold voltages. Achieving efficient electron emission on large scale has a lot of challenges such as screening effect, pull-off and lower current efficiency. We have explored the use of polymer-CNT composite structures to overcome these challenges in this work. NA

Structural features of spin-coated thin films of binary As{sub x}S{sub 100−x} chalcogenide glass system

Energy Technology Data Exchange (ETDEWEB)

Cook, J. [Austin Peay State University, Clarksville, TN 37075 (United States); Slang, S. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Golovchak, R. [Austin Peay State University, Clarksville, TN 37075 (United States); Jain, H. [International Materials Institute for New Functionality in Glass, Lehigh University, Bethlehem, PA 18015 (United States); Vlcek, M. [Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Kovalskiy, A., E-mail: kovalskyya@apsu.edu [Austin Peay State University, Clarksville, TN 37075 (United States)

2015-08-31

Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As{sub x}S{sub 100−x} (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic–inorganic interface. - Highlights: • As–S spin-coated chalcogenide thin films with different As/S were fabricated. • XPS measurements support the cluster-like structure of spin-coated films. • As{sub 2}O{sub 3} was confirmed as the composition of precipitate formed during dissolution. • Lack of As–As bonds explains the observed photostability of the thin films.

Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces

Science.gov (United States)

Dussinger, Peter M.; Lindemuth, James E.

1997-01-01

The principal objective of this Phase 2 SBIR program was to develop and demonstrate a practically insoluble coating for nickel-based superalloys for Stirling engine heat pipe applications. Specific technical objectives of the program were: (1) Determine the solubility corrosion rates for Nickel 200, Inconel 718, and Udimet 72OLI in a simulated Stirling engine heat pipe environment, (2) Develop coating processes and techniques for capillary groove and screen wick structures, (3) Evaluate the durability and solubility corrosion rates for capillary groove and screen wick structures coated with an insoluble coating in cylindrical heat pipes operating under Stirling engine conditions, and (4) Design and fabricate a coated full-scale, partial segment of the current Stirling engine heat pipe for the Stirling Space Power Convertor program. The work effort successfully demonstrated a two-step nickel aluminide coating process for groove wick structures and interior wall surfaces in contact with liquid metals; demonstrated a one-step nickel aluminide coating process for nickel screen wick structures; and developed and demonstrated a two-step aluminum-to-nickel aluminide coating process for nickel screen wick structures. In addition, the full-scale, partial segment was fabricated and the interior surfaces and wick structures were coated. The heat pipe was charged with sodium, processed, and scheduled to be life tested for up to ten years as a Phase 3 effort.

Laminated composite based on polyester geotextile fibers and polyurethane resin for coating wood structures

OpenAIRE

Assagra,Yuri Andrey Olivato; Altafim,Ruy Alberto Pisani; Silva,José Francisco Resende da; Basso,Heitor Cury; Lahr,Francisco Antonio Rocco; Altafim,Ruy Alberto Corrêa

2013-01-01

New environmental laws have restricted the use of hardwood trees in overhead power lines structures, such as, poles and cross-arms, leading companies to seek alternative materials. Reforested wood coated with polymeric resin has been proposed as an environmental friendly solution, with improved electrical properties and protection against external agents, e.g. moisture, ultraviolet radiation and fungi. However, the single thin layer of resin, normally applied on such structures reveal to be i...

Microstructural analysis and mechanical characterization of aluminum matrix nanocomposites reinforced with uncoated and Cu-coated alumina particles

Energy Technology Data Exchange (ETDEWEB)

Beygi, H., E-mail: hossein.beygi@stu-mail.um.ac.ir; Sajjadi, S.A.; Zebarjad, S.M.

2014-06-01

Aluminum matrix composites used in the aerospace, military and automotive industries are typically fabricated by a stir casting method. However, when nanoparticles are used for reinforcement, fabrication of composite materials by this method leads to the formation of a large number of structural defects. In this study, copper coating of alumina reinforcement particles is investigated as a technique for improving the structure of Al-Al{sub 2}O{sub 3} composites. Microstructural investigations by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersion spectroscopy (EDS) and transmission electron microscopy (TEM) showed that the alumina particles were coated uniformly with copper shells. Copper coating of the reinforcing particles significantly increased their wettability in the molten aluminum alloy, strengthened the matrix-particle interfaces and improved the distribution of reinforcing particles within the matrix. Due to these microstructural improvements, the hardness, compressive strength, yield stress, tensile strength and elongation of the composites were enhanced by copper coating of the alumina particles.

Microstructural analysis and mechanical characterization of aluminum matrix nanocomposites reinforced with uncoated and Cu-coated alumina particles

International Nuclear Information System (INIS)

Beygi, H.; Sajjadi, S.A.; Zebarjad, S.M.

2014-01-01

Aluminum matrix composites used in the aerospace, military and automotive industries are typically fabricated by a stir casting method. However, when nanoparticles are used for reinforcement, fabrication of composite materials by this method leads to the formation of a large number of structural defects. In this study, copper coating of alumina reinforcement particles is investigated as a technique for improving the structure of Al-Al 2 O 3 composites. Microstructural investigations by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersion spectroscopy (EDS) and transmission electron microscopy (TEM) showed that the alumina particles were coated uniformly with copper shells. Copper coating of the reinforcing particles significantly increased their wettability in the molten aluminum alloy, strengthened the matrix-particle interfaces and improved the distribution of reinforcing particles within the matrix. Due to these microstructural improvements, the hardness, compressive strength, yield stress, tensile strength and elongation of the composites were enhanced by copper coating of the alumina particles

Effect of structure and deposition technology on tribological properties of DLC coatings alloyed with VIA group metals

Science.gov (United States)

Khrushchov, M.; Levin, I.; Marchenko, E.; Avdyukhina, V.; Petrzhik, M.

2016-07-01

The results of a comprehensive research on atomic structure, phase composition, micromechanical and tribological characteristics of alloyed DLC coatings have been presented. The coatings have been deposited by reactive magnetron sputtering in acetylene-nitrogen gas mixtures of different compositions (a-C:H:Cr), by plasma-assisted chemical vapor deposition in atmospheres of silicone-organic precursor gases (a-C:H:Mo:Si), and by nonreactive magnetron sputtering of a composite target (a-C:H:W).

The effects to the structure and electrochemical behavior of zinc phosphate conversion coatings with ethanolamine on magnesium alloy AZ91D

International Nuclear Information System (INIS)

Li Qing; Xu Shuqiang; Hu Junying; Zhang Shiyan; Zhong Xiankang; Yang Xiaokui

2010-01-01

This paper discussed a zinc phosphate conversion coating formed on magnesium alloy AZ91D from the phosphating bath with varying amounts of ethanolamine (MEA). The effects of MEA on the form, structure, phase composition and electrochemical behavior of the phosphate coatings were examined using an scanning electron microscopy (SEM), X-ray diffraction (XRD) potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Interpretations of the electrical elements of the equivalent circuit were obtained from the SEM structure of the coatings, assumed to be formed of two layers: an outer porous crystal layer and an inner flat amorphous layer. The result showed that adding MEA refined the microstructure of the crystal layer and that the phosphate coating, derived at the optimal content of 1.2 g/L, with the most uniform and compact outer crystal layer provided the best corrosion protection.

Electrodeposition of Ni–W–Al{sub 2}O{sub 3} nanocomposite coating with functionally graded microstructure

Energy Technology Data Exchange (ETDEWEB)

Allahyarzadeh, M.H.; Aliofkhazraei, M., E-mail: maliofkh@gmail.com; Rouhaghdam, A.R. Sabour; Torabinejad, V.

2016-05-05

Electrodeposition of functionally graded (FG) Ni–W–Al{sub 2}O{sub 3} nanocomposite coatings is investigated in current research. These types of coatings were applied in a way that alumina content was increased from the substrate towards the surface of the coating; hence, Ni–W would possess improved wear and corrosion resistance properties. FG-coatings were developed by the variation of duty cycle and frequency. The microstructure and elemental analysis of the coating as a function of thickness was investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis, respectively. The corrosion resistance of the FG-coatings was evaluated using potentiodynamic polarization and the wear behavior was also studied using pin-on-disk wear tests. In order to investigate hardness properties of the coating, microhardness measurements were carried out on cross-section of coatings. Results revealed that the alumina content and the microhardness increased towards the surface. Results also showed the corrosion and wear resistance of FG-coatings were significantly improved by addition of α-Al{sub 2}O{sub 3} nanoparticles. Profilometery and AFM results also revealed that surface roughness was influenced by pulse plating parameters. - Highlights: • Functionally graded structures have been synthesized using adjusting pulse parameters. • Al{sub 2}O{sub 3} and W contents increases gradually as a function of coating thickness. • Alumina increased the corrosion resistance by moderating i{sub corr} and E{sub corr}. • Wear behavior has been enhanced in functionally graded structure.

Structure, MC3T3-E1 cell response, and osseointegration of macroporous titanium implants covered by a bioactive microarc oxidation coating with microporous structure.

Science.gov (United States)

Zhou, Rui; Wei, Daqing; Cheng, Su; Feng, Wei; Du, Qing; Yang, Haoyue; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu

2014-04-09

Macroporous Ti with macropores of 50-400 μm size is prepared by sintering Ti microbeads with different diameters of 100, 200, 400, and 600 μm. Bioactive microarc oxidation (MAO) coatings with micropores of 2-5 μm size are prepared on the macroporous Ti. The MAO coatings are composed of a few TiO2 nanocrystals and lots of amorphous phases with Si, Ca, Ti, Na, and O elements. Compared to compact Ti, the MC3T3-E1 cell attachment is prolonged on macroporous Ti without and with MAO coatings; however, the cell proliferation number increases. These results are contributed to the effects of the space structure of macroporous Ti and the surface chemical feature and element dissolution of the MAO coatings during the cell culture. Macroporous Ti both without and with MAO coatings does not cause any adverse effects in vivo. The new bone grows well into the macropores and micropores of macroporous Ti with MAO coatings, showing good mechanical properties in vivo compared to Ti, MAO-treated Ti, and macroporous Ti because of its excellent osseointegration. Moreover, the MAO coatings not only show a high interface bonding strength with new bones but also connect well with macroporous Ti. Furthermore, the pushing out force for macroporous Ti with MAO coatings increases significantly with increasing microbead diameter.

Tablet coating by injection molding technology - Optimization of coating formulation attributes and coating process parameters.

Science.gov (United States)

Desai, Parind M; Puri, Vibha; Brancazio, David; Halkude, Bhakti S; Hartman, Jeremy E; Wahane, Aniket V; Martinez, Alexander R; Jensen, Keith D; Harinath, Eranda; Braatz, Richard D; Chun, Jung-Hoon; Trout, Bernhardt L

2018-01-01

We developed and evaluated a solvent-free injection molding (IM) coating technology that could be suitable for continuous manufacturing via incorporation with IM tableting. Coating formulations (coating polymers and plasticizers) were prepared using hot-melt extrusion and screened via stress-strain analysis employing a universal testing machine. Selected coating formulations were studied for their melt flow characteristics. Tablets were coated using a vertical injection molding unit. Process parameters like softening temperature, injection pressure, and cooling temperature played a very important role in IM coating processing. IM coating employing polyethylene oxide (PEO) based formulations required sufficient room humidity (>30% RH) to avoid immediate cracks, whereas other formulations were insensitive to the room humidity. Tested formulations based on Eudrajit E PO and Kollicoat IR had unsuitable mechanical properties. Three coating formulations based on hydroxypropyl pea starch, PEO 1,000,000 and Opadry had favorable mechanical (35% elongation, >95×10 4 J/m 3 toughness) and melt flow (>0.4g/min) characteristics, that rendered acceptable IM coats. These three formulations increased the dissolution time by 10, 15 and 35min, respectively (75% drug release), compared to the uncoated tablets (15min). Coated tablets stored in several environmental conditions remained stable to cracking for the evaluated 8-week time period. Copyright © 2017 Elsevier B.V. All rights reserved.

Friction surfaced Stellite6 coatings

International Nuclear Information System (INIS)

Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

2012-01-01

Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: ► Stellite6 used as coating material for friction surfacing. ► Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. ► Finer and uniformly distributed carbides in friction surfaced coatings. ► Absence of melting results compositional homogeneity in FS Stellite6 coatings.

Investigation of stand-off distance effect on structure, adhesion and hardness of copper coatings obtained by the APS technique

Science.gov (United States)

Masoumeh, Goudarzi; Shahrooz, Saviz; Mahmood, Ghoranneviss; Ahmad, Salar Elahi

2018-03-01

The outbreak of the disease and infection in the hospital environment and medical equipment is one of the concerns of modern life. One of the effective ways for preventing and reducing the complications of infections is modification of the surface. Here, the handmade atmospheric plasma spray system is used for accumulating copper as an antibacterial agent on the 316L stainless steel substrate, which applies to hospital environment and medical equipment. As a durable coating with proper adhesion is needed on the substrate, the effect of stand-off distance (SOD) which is an important parameter of the spray on the microstructure, the hardness and adhesion of the copper coating on the 316L stainless steel were investigated. The structure and phase composition of copper depositions were investigated using scanning electron microscopy and X-ray diffraction. The adhesion and hardness of depositions are evidenced using the cross cut tester and Vickers hardness tester, respectively. The findings confirm that the voids in the coatings increase with increasing SOD, which leads to decreasing the hardness of coatings and also the adhesion strength between depositions and substrate. In addition, by increasing the SOD, the oxygen content and the size of grains in the lamellae (fine structure) of coatings also increase.

Silicon effects on formation of EPO oxide coatings on aluminum alloys

International Nuclear Information System (INIS)

Wang, L.; Nie, X.

2006-01-01

Electrolytic plasma processes (EPP) can be used for cleaning, metal-coating, carburizing, nitriding, and oxidizing. Electrolytic plasma oxidizing (EPO) is an advanced technique to deposit thick and hard ceramic coatings on a number of aluminum alloys. However, the EPO treatment on Al-Si alloys with a high Si content has rarely been reported. In this research, an investigation was conducted to clarify the effects of silicon contents on the EPO coating formation, morphology, and composition. Cast hypereutectic 390 alloys (∼ 17% Si) and hypoeutectic 319 alloys (∼ 7% Si) were chosen as substrates. The coating morphology, composition, and microstructure of the EPO coatings on those substrates were investigated using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). A stylus roughness tester was used for surface roughness measurement. It was found that the EPO process had four stages where each stage was corresponding to various coating surface morphology, composition, and phase structures, characterised by different coating growth mechanisms

Porous SiO{sub 2} nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

Energy Technology Data Exchange (ETDEWEB)

Das, Indranee [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); De, Goutam, E-mail: gde@cgcri.res.in [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Hupa, Leena [Johan Gadolin Process Chemistry Centre, Åbo Akademi University, FI-20500 Åbo (Finland); Vallittu, Pekka K. [Turku Clinical Biomaterials Centre—TCBC, University of Turku, FI-20520 Turku (Finland); Institute of Dentistry, University of Turku, Department of Biomaterials Science and City of Turku, Welfare Division, Turku (Finland)

2016-05-01

A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO{sub 2} nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

Highly transparent, stable, and superhydrophobic coatings based on gradient structure design and fast regeneration from physical damage

Science.gov (United States)

Chen, Zao; Liu, Xiaojiang; Wang, Yan; Li, Jun; Guan, Zisheng

2015-12-01

Optical transparency, mechanical flexibility, and fast regeneration are important factors to expand the application of superhydrophobic surfaces. Herein, we fabricated highly transparent, stable, and superhydrophobic coatings through a novel gradient structure design by versatile dip-coating of silica colloid particles (SCPs) and diethoxydimethysiliane cross-linked silica nanoparticles (DDS-SNPs) on polyethylene terephthalate (PET) film and glass, followed by the modification of octadecyltrichlorosiliane (OTCS). When the DDS concentration reached 5 wt%, the modified SCPs/DDS-SNPs coating exhibited a water contact angle (WCA) of 153° and a sliding angle (SA) glass was increased by 2.7% and 1% in the visible wavelength, respectively. This superhydrophobic coating also showed good robustness and stability against water dropping impact, ultrasonic damage, and acid solution. Moreover, the superhydrophobic PET film after physical damage can quickly regain the superhydrophobicity by one-step spray regenerative solution of dodecyltrichlorosilane (DTCS) modified silica nanoparticles at room temperature. The demonstrated method for the preparation and regeneration of superhydrophobic coating is available for different substrates and large-scale production at room temperature.

Histologic analysis of a retrieved hydroxyapatite-coated femoral prosthesis

DEFF Research Database (Denmark)

Søballe, K; Gotfredsen, K; Brockstedt-Rasmussen, H

1991-01-01

A hydroxyapatite-coated hip hemi-prosthesis was retrieved from a 98-year-old osteoporotic woman 12 weeks after implantation. Histologic analysis revealed bone and fibrous tissue almost evenly distributed around the surface of the implant circumference. Quantitative histologic analysis showed...... that 48% of the hydroxyapatite surface was covered by bone. Fibrous tissue covered 30% of the prosthetic surface, and 20% of the surface had no tissue coverage. Scanning electron microscopy showed direct contact without any clear boundary between the newly formed bone and the hydroxyapatite ceramic....

Transcriptome Analysis of a New Peanut Seed Coat Mutant for the Physiological Regulatory Mechanism Involved in Seed Coat Cracking and Pigmentation

Science.gov (United States)

Wan, Liyun; Li, Bei; Pandey, Manish K.; Wu, Yanshan; Lei, Yong; Yan, Liying; Dai, Xiaofeng; Jiang, Huifang; Zhang, Juncheng; Wei, Guo; Varshney, Rajeev K.; Liao, Boshou

2016-01-01

Seed-coat cracking and undesirable color of seed coat highly affects external appearance and commercial value of peanuts (Arachis hypogaea L.). With an objective to find genetic solution to the above problems, a peanut mutant with cracking and brown colored seed coat (testa) was identified from an EMS treated mutant population and designated as “peanut seed coat crack and brown color mutant line (pscb).” The seed coat weight of the mutant was almost twice of the wild type, and the germination time was significantly shorter than wild type. Further, the mutant had lower level of lignin, anthocyanin, proanthocyanidin content, and highly increased level of melanin content as compared to wild type. Using RNA-Seq, we examined the seed coat transcriptome in three stages of seed development in the wild type and the pscb mutant. The RNA-Seq analysis revealed presence of highly differentially expressed phenylpropanoid and flavonoid pathway genes in all the three seed development stages, especially at 40 days after flowering (DAF40). Also, the expression of polyphenol oxidases and peroxidase were found to be activated significantly especially in the late seed developmental stage. The genome-wide comparative study of the expression profiles revealed 62 differentially expressed genes common across all the three stages. By analyzing the expression patterns and the sequences of the common differentially expressed genes of the three stages, three candidate genes namely c36498_g1 (CCoAOMT1), c40902_g2 (kinesin), and c33560_g1 (MYB3) were identified responsible for seed-coat cracking and brown color phenotype. Therefore, this study not only provided candidate genes but also provided greater insights and molecular genetic control of peanut seed-coat cracking and color variation. The information generated in this study will facilitate further identification of causal gene and diagnostic markers for breeding improved peanut varieties with smooth and desirable seed coat color. PMID

Superhydrophobic silica coating by dip coating method

International Nuclear Information System (INIS)

Mahadik, Satish A.; Parale, Vinayak; Vhatkara, Rajiv S.; Mahadik, Dinesh B.; Kavale, Mahendra S.; Wagh, Pratap B.; Gupta, Satish; Gurav, Jyoti

2013-01-01

Herein, we report a simple and low cost method for the fabrication of superhydrophobic coating surface on quartz substrates via sol-gel dip coating method at room temperature. Desired surface chemistry and texture growth for superhydrophobicity developed under double step sol–gel process at room temperature. The resultant superhydrophobic surfaces were characterized by Field-emission scanning electron microscopy (FE-SEM), Atomic force microscopy (AFM), water contact angle (WCA) measurement, differential thermal gravimetric analysis-differential thermal analysis (TGA-DTA) calorimetry and optical spectrometer. Coating shows the ultra high water contact angle about 168 ± 2° and water sliding angle 3 ± 1° and superoleophilic with petroleum oils. This approach allows a simple strategy for the fabrication process of superhydrophilic–superhydrophobic on same surfaces with high thermal stability of superhydrophobicity up to 560 °C. Thus, durability, special wettability and thermal stability of superhydrophobicity expand their application fields.

Development of antimicrobial coating by later-by-layer dip coating of chlorhexidine-loaded micelles.

Science.gov (United States)

Tambunlertchai, Supreeda; Srisang, Siriwan; Nasongkla, Norased

2017-06-01

Layer-by-layer (LbL) dip coating, accompanying with the use of micelle structure, allows hydrophobic molecules to be coated on medical devices' surface via hydrogen bonding interaction. In addition, micelle structure also allows control release of encapsulated compound. In this research, we investigated methods to coat and maximize the amount of chlorhexidine (CHX) on silicone surface through LbL dip coating method utilizing hydrogen bonding interaction between PEG on micelle corona and PAA. The number of coated cycles was varied in the process and 90 coating cycles provided the maximum amount of CHX loaded onto the surface. In addition, pre-coating the surface with PAA enhanced the amount of coated CHX by 20%. Scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to validate and characterize the coating. For control release aspect, the coated film tended to disrupt at physiological condition; hence chemical crosslinking was performed to minimize the disruption and maximize the release time. Chemical crosslinking at pH 2.5 and 4.5 were performed in the process. It was found that chemical crosslinking could help extend the release period up to 18 days. This was significantly longer when compared to the non-crosslinking silicone tube that could only prolong the release for 5 days. In addition, chemical crosslinking at pH 2.5 gave higher and better initial burst release, release period and antimicrobial properties than that of pH 4.5 or the normal used pH for chemical crosslinking process.

Architecture and assembly of the Bacillus subtilis spore coat.

Science.gov (United States)

Plomp, Marco; Carroll, Alicia Monroe; Setlow, Peter; Malkin, Alexander J

2014-01-01

Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of "nanodot" particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization

Architecture and Assembly of the Bacillus subtilis Spore Coat

Science.gov (United States)

Plomp, Marco; Carroll, Alicia Monroe; Setlow, Peter; Malkin, Alexander J.

2014-01-01

Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of “nanodot” particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization

CVD diamond coatings on titanium : Characterisation by XRD techniques

Energy Technology Data Exchange (ETDEWEB)

Cappuccio, G [CNR, Frascati, Rome (Italy). Istituto di Strutturistica Chimica; [INFN-LNF, Frascati, Rome (Italy). Laboratorio Dafne Luce

1996-09-01

Here, the authors report an analysis carried out on diamond coatings on titanium substrates to show the potentially of x-ray diffraction techniques in the structural characterisation both of diamond thin films and of the other phases (TiC and TiH{sub 2}) present in the interfacial layer. It should be noted that the composition and microstructure of the interface layers strongly affect the characteristics of the diamond films, particularly adhesion, which is one of the most important elements determining the final quality of the coating.

Electroless nickel – phosphorus coating on crab shell particles and its characterization

Energy Technology Data Exchange (ETDEWEB)

Arulvel, S., E-mail: gs.arulvel.research@gmail.com; Elayaperumal, A.; Jagatheeshwaran, M.S.

2017-04-15

Being hydrophilic material, crab shell particles have only a limited number of applications. It is, therefore, necessary to modify the surface of the crab shell particles. To make them useful ever for the applications, the main theme we proposed in this article is to utilize crab shell particles (CSP) with the core coated with nickel phosphorus (NiP) as a shell using the electroless coating process. For dealing with serious environmental problems, utilization of waste bio-shells is always an important factor to be considered. Chelating ability of crab shell particles eliminates the surface activation in this work proceeding to the coating process. The functional group, phase structure, microstructure, chemical composition and thermal analysis of CSP and NiP/CSP were characterized using Fourier transform infra-red spectroscopy (FTIR), x-ray diffraction analyzer (XRD), scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The combination of an amorphous and crystalline structure was exhibited by CSP and NiP/CSP. NiP/CSP has shown a better thermal stability when compared to uncoated CSP. Stability test, adsorption test, and conductivity test were conducted for the study of adsorption behavior and conductivity of the particles. CSP presented a hydrophilic property in contrast to hydrophobic NiP/CSP. NiP/CSP presented a conductivity of about 44% greater compared to the CSP without any fluctuations. - Highlights: • Utilization of crab shell waste is focused on. • NiP coating on crab shell particle is fabricated using electroless process. • Thermal analysis, stability test, adsorption test and conductivity test were done. • Organic matrix of crab shell particle favors the coating process. • Results demonstrate the characterization of CSP core – NiP shell structure.

Behaviour of plasma spray coatings under disruption simulation

International Nuclear Information System (INIS)

Brossa, F.; Rigon, G.; Looman, B.

1988-01-01

The behaviour of metallic and ceramic protective coatings under disruption simulations was studied correlating the damage with their physical and structural parameters. Plasma Spray (PS) and Vacuum Plasma Spray (VPS) were the techniques used for the production of the coatings. W-5% Re was selected for divertor plates, and TiC, TiO 2 , Al 2 O 3 , low-Z ceramic materials for the first wall protection on 316 SS, Cu and Al as substrates. An electron beam gun was used to simulate the plasma disruptions. The tests were carried out from 0.6 to 6 MJ/m 2 . The thermal effects were studied by metallographic and EDXA analysis. The damage was observed comparing the degree of protection provided by each coating to discover the minimum thickness necessary to prevent the underlying material from melting. Good protective coatings must have a high melting point, great porosity and low thermal conductivity. Such coatings act as thermal barriers, increasing the surface temperature and radiating back large parts of the energy. (orig.)

Wannier–Stark electro-optical effect, quasi-guided and photonic modes in 2D macroporous silicon structures with SiO_2 coatings

International Nuclear Information System (INIS)

Karachevtseva, L.; Goltviansky, Yu.; Sapelnikova, O.; Lytvynenko, O.; Stronska, O.; Bo, Wang; Kartel, M.

2016-01-01

Highlights: • The IR absorption spectra of oxidized macroporous silicon were studied. • The Wannier–Stark electro-optical effect on Si-SiO_2 boundary was confirmed. • An additional electric field of quasi-guided optical modes was evaluated. • The photonic modes and band gaps were measured as peculiarities in absorption spectra. - Abstract: Opportunities to enhance the properties of structured surfaces were demonstrated on 2D macroporous silicon structures with SiO_2 coatings. We investigated the IR light absorption oscillations in macroporous silicon structures with SiO2 coatings 0–800 nm thick. The Wannier–Stark electro-optical effect due to strong electric field on Si-SiO_2boundary and an additional electric field of quasi-guided optical modes were taken into account. The photonic modes and band gaps were also considered as peculiarities in absorbance spectra of macroporous silicon structures with a thick SiO_2 coating. The photonic modes do not coincide with the quasi-guided modes in the silicon matrix and do not appear in absorption spectra of 2D macroporous silicon structures with surface nanocrystals.

Structure and properties of a duplex coating combining micro-arc oxidation and baking layer on AZ91D Mg alloy

Energy Technology Data Exchange (ETDEWEB)

Cui, Xue-Jun; Li, Ming-Tian; Yang, Rui-Song; Yu, Zu-Xiao [Material Corrosion and Protection Key Laboratory of Sichuan province, Sichuan University of Science and Engineering, Zigong 643000 (China); College of Materials and Chemical Engineering, Sichuan University of Science and Engineering, Zigong 643000 (China)

2016-02-15

Graphical abstract: - Highlights: • A duplex coating was fabricated through combining MAO and baking layer. • A baking coating with a thickness of 92 μm was created on MAO-coated Mg alloy. • The duplex coating noticeably improved the corrosion resistance of Mg alloy. • The related corrosion and wear mechanisms were investigated. - Abstract: A duplex coating (called MAOB coating) was fabricated on AZ91D Mg alloy by combining the process of micro-arc oxidation (MAO) with baking coating (B-coating). The structure, composition, corrosion resistance, and tribological behaviour of the coatings were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrochemical and long-term immersion test, and ball-on-disc friction test. The results show that a dense 92 μm thick B-coating was tightly deposited onto the MAO-coated Mg alloy and exhibited a good mechanical interlock along the rough interface. Compared with the MAO-coated sample, the corrosion current density of the MAOB-coated Mg alloy decreased by two or three orders of magnitude and no corrosion phenomenon was observed during a long-term immersion test of about 500 h (severe corrosion pits were found for MAO-treated samples after about 168 h of immersion). The frictional coefficient values of the MAOB coating were similar to those of the MAO coating using dry sliding tests, while the B-coating on the MAO-coated surface significantly improved the wear resistance of the AZ91D Mg alloy. All of these results indicate that a B-coating can be used to further protect Mg alloys from corrosion and wear by providing a thick, dense barrier.

Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

KAUST Repository

Wilke, Marcus

2011-12-01

In the last years, glow discharge optical emission spectrometry (GDOES) gained more and more acceptance in the analysis of functional coatings. GDOES thereby represents an interesting alternative to common depth profiling techniques like AES and SIMS, based on its unique combination of high erosion rates and erosion depths, sensitivity, analysis of nonconductive layers and easy quantification even for light elements such as C, N, O and H. Starting with the fundamentals of GDOES, a short overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings and thin films. Results illustrating the high depth resolution, confirmation of stoichiometry, the detection of light elements in coatings as well as contamination on the surface or interfaces will be demonstrated by measurements of: a multilayer system Cr/Ti on silicon, interface contamination on silicon during deposition of aluminum, Al2O3-nanoparticle containing conversion coatings on zinc for corrosion resistance, Ti3SiC2 MAX-phase coatings by pulsed laser deposition and hydrogen detection in a V/Fe multilayer system. The selected examples illustrate that GDOES can be successfully adopted as an analytical tool in the development of new materials and coatings. A discussion of the results as well as of the limitations of GDOES is presented. © 2011 Elsevier B.V.

Effect of Ti content on structure and properties of Al2CrFeNiCoCuTix high-entropy alloy coatings

International Nuclear Information System (INIS)

Qiu, X.W.; Zhang, Y.P.; Liu, C.G.

2014-01-01

Highlights: • Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. • Al 2 CrFeNiCoCuTi x coatings show excellent corrosion resistance and wear resistance. • Al 2 CrFeNiCoCuTi x coatings play a good protective effect on Q235 steel. • Ti element promotes the formation of a BCC structure in a certain extent. -- Abstract: The Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. The structure, hardness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al 2 CrFeNiCoCuTi x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combination; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings is reduced by 1–2 orders of magnitude, the free-corrosion potential is more “positive”. With the increasing of Ti content, the corrosion resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings enhanced in 0.5 mol/L HNO 3 solution. Compared with Q235 steel, the relative wear resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti 0.0 high-entropy alloy is a kind of soft magnetic materials

Improving the Corrosion Resistance of Biodegradable Magnesium Alloys by Diffusion Coating Process

Science.gov (United States)

Levy, Galit Katarivas; Aghion, Eli

Magnesium alloys suffer from accelerated corrosion in physiological environment and hence their use as a structural material for biodegradable implants is limited. The present study focuses on a diffusion coating treatment that amplifies the beneficial effect of Neodymium on the corrosion resistance of magnesium alloys. The diffusion coating layer was obtained by applying 1 µm Nd coating on EW10X04 magnesium alloy using Electron-gun evaporator and PVD process. The coated alloy was heat treated at 350°C for 3 hours in a protective atmosphere of N2+0.2%SF6. The micro structure characteristics were evaluated by SEM, XRD, and XPS; the corrosion resistance was examined by potentiodynamic polarization and EIS analysis. The corrosion resistance of the diffusion coated alloy was significantly improved compared to the uncoated material. This was related to: (i) formation of Nd2O3 in the outer scale, (ii) integration of Nd in the MgO oxide layer, and (iii) formation of secondary phase Mg41Nd5 along the grain boundaries of α-Mg.

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications

Science.gov (United States)

Eliaz, Noam; Metoki, Noah

2017-01-01

Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs. PMID:28772697

Model-based analysis of thermal insulation coatings

DEFF Research Database (Denmark)

Kiil, Søren

2014-01-01

Thermal insulation properties of coatings based on selected functional filler materials are investigated. The underlying physics, thermal conductivity of a heterogeneous two-component coating, and porosity and thermal conductivity of hollow spheres (HS) are quantified and a mathematical model for...

Tribological Performance Optimization of Electroless Ni-P-W Coating Using Weighted Principal Component Analysis

Directory of Open Access Journals (Sweden)

S. Roy

2013-12-01

Full Text Available The present investigation is an experimental approach to deposit electroless Ni-P-W coating on mild steel substrate and find out the optimum combination of various tribological performances on the basis of minimum friction and wear, using weighted principal component analysis (WPCA. In this study three main tribological parameters are chosen viz. load (A, speed (B and time(C. The responses are coefficient of friction and wear depth. Here Weighted Principal Component Analysis (WPCA method is adopted to convert the multi-responses into single performance index called multiple performance index (MPI and Taguchi L27 orthogonal array is used to design the experiment and to find the optimum combination of tribological parameters for minimum coefficient of friction and wear depth. ANOVA is performed to find the significance of the each tribological process parameters and their interactions. The EDX analysis, SEM and XRD are performed to study the composition and structural aspects.

Structure of clathrin-coated vesicles from small-angle scattering experiments

DEFF Research Database (Denmark)

Pedersen, J.S.

1993-01-01

Previously published small-angle neutron and X-ray scattering data from coated vesicles, reassembled coats, and stripped vesicles have been analyzed in terms of one common model. The neutron data sets include contrast variation measurements at three different D2O solvent concentrations. The model...... used for interpreting the data has spherical symmetry and explicitly takes into account polydispersity, which is described by a Gaussian distribution. A constant thickness of the clathrin coats is assumed. The fitting of the model shows that the coated vesicles consist of a low-density outer protein....... Thus, the membrane and the high-density protein shell overlap in space, which shows that the lipid membrane contains protein. The molecular mass of the average particle is 27 x 10(6) Da. The coated vesicles consist, on average, of approximately 85% protein and 15% lipids. About 40% of the protein mass...

The effects of phase transformation on the structure and mechanical properties of TiSiCN nanocomposite coatings deposited by PECVD method

Science.gov (United States)

Abedi, Mohammad; Abdollah-zadeh, Amir; Bestetti, Massimiliano; Vicenzo, Antonello; Serafini, Andrea; Movassagh-Alanagh, Farid

2018-06-01

In the present study, the effects of phase transformations on the structure and mechanical properties of TiSiCN coatings were investigated. TiSiCN nanocomposite coatings were deposited on AISI H13 hot-work tool steel by a pulsed direct current plasma-enhanced chemical vapor deposition process at 350 or 500 °C, using TiCl4 and SiCl4 as the precursors of Ti and Si, respectively, in a CH4/N2/H2/Ar plasma as the source of carbon and nitrogen and reducing environment. Some samples deposited at 350 °C were subsequently annealed at 500 °C under Ar atmosphere. Super hard self-lubricant TiSiCN coatings, having nanocomposite structure consisting of TiCN nanocrystals and amorphous carbon particles embedded in an amorphous SiCNx matrix, formed through spinodal decomposition in the specimens deposited or annealed at 500 °C. In addition, it was revealed that either uncomplete or relatively coarse phase segregation of titanium compounds was achieved during deposition at 350 °C and 500 °C, respectively. On the contrary, by deposition at 350 °C followed by annealing at 500 °C, a finer structure was obtained with a sensible improvement of the mechanical properties of coatings. Accordingly, the main finding of this work is that significant enhancement in key properties of TiSiCN coatings, such as hardness, adhesion and friction coefficient, can be obtained by deposition at low temperature and subsequent annealing at higher temperature, thanks to the formation of a fine grained nanocomposite structure.

Effect of H2O and Y(O on Oxidation Behavior of NiCoCrAl Coating Within Thermal Barrier Coating

Directory of Open Access Journals (Sweden)

WANG Yi-qun

2017-04-01

Full Text Available NiCoCrAl coatings containing Y and Y oxide were made using vacuum plasma deposition and high-velocity oxygen fuel respectively, high temperature oxidation dynamics and cross-section microstructures of NiCoCrAl+Y and NiCoCrAl+Y(O coatings in Ar-16.7%O2, Ar-3.3%H2O and Ar-0.2%H2-0.9%H2O at 1100℃ were investigated by differential thermal analysis (DTA and optical and electron microscope. The influencing mechanism of Y oxide on the oxidation of coatings at different atmosphere was compared by computation using First-Principles. The results show that Al2O3 layer on NiCoCrAl+Y coatings has more holes for internal oxidation on account of the element Y diffusion and enrichment on the interface. In addition, steam can promote the internal oxidation. While a thinner and uniform alumina form on NiCoCrAl+Y(O coatings because element Y is pinned by oxygen atoms during the preparation of coatings. Water vapor has less influence on protective alumina formation on the NiCoCrAl+Y(O coating. Therefore, oxidation behavior of NiCoCrAl coatings vary in composition and structure in different oxidizing atmosphere. Besides, Y and Y-enrichment oxides have key influences on the microstructure and the growth rate.

Porous SiO2 nanofiber grafted novel bioactive glass-ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant.

Science.gov (United States)

Das, Indranee; De, Goutam; Hupa, Leena; Vallittu, Pekka K

2016-05-01

A composite bioactive glass-ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of Annealing Temperature and Spin Coating Speed on Mn-Doped ZnS Nanocrystals Thin Film by Spin Coating

Directory of Open Access Journals (Sweden)

Noor Azie Azura Mohd Arif

2017-01-01

Full Text Available ZnS:Mn nanocrystals thin film was fabricated at 300°C and 500°C via the spin coating method. Its sol-gel was spin coated for 20 s at 3000 rpm and 4000 rpm with metal tape being used to mold the shape of the thin film. A different combination of these parameters was used to investigate their influences on the fabrication of the film. Optical and structural characterizations have been performed. Optical characterization was analyzed using UV-visible spectroscopy and photoluminescence spectrophotometer while the structural and compositional analysis of films was measured via field emission scanning electron microscopy and energy dispersive X-ray. From UV-vis spectra, the wavelength of the ZnS:Mn was 250 nm and the band gap was within the range 4.43 eV–4.60 eV. In room temperature PL spectra, there were two emission peaks centered at 460 nm and 590 nm. Under higher annealing temperature and higher speed used in spin coating, an increase of 0.05 eV was observed. It was concluded that the spin coating process is able to synthesize high quality spherical ZnS:Mn nanocrystals. This conventional process can replace other high technology methods due to its synthesis cost.

Silane based coating of aluminium mold

DEFF Research Database (Denmark)

2013-01-01

having at least one closed cavity is provided, at least one surface of the at least one cavity being an aluminium surface coated with a silane based coating layer. The silane based anti-stiction coating improves the anti-stiction properties of the mold which may allow for molding and demolding...... of structures which would otherwise be difficult to mold. The resistance of the coated aluminium mold is significantly improved by applying a silane-based coating layer....

Polyelectrolyte coatings prevent interferences from charged nanoparticles in SPME speciation analysis

International Nuclear Information System (INIS)

Zielińska, Katarzyna; Leeuwen, Herman P. van

2014-01-01

Highlights: • For the first time SPME fiber is coated with polyelectrolyte layer. • Sorption of nanoparticles on the solid phase surface is prevented. • Polyelectrolyte-modified fiber enables extraction of free analyte in presence of sorbing nanoparticles. - Abstract: In this work we present a new approach for protection of the fiber in solid phase microextraction (SPME) from interfering charged particles present in the sample medium. It involves coating of commercial poly(dimethylsiloxane) extraction phase with polyelectrolyte layer composed of poly(diallyldimethylammonium chloride), and poly(sodium 4-styrenesulfonate). The modified fiber provides reproducible, convenient and fast extraction capabilities toward the model analyte, triclosan (TCS). A negatively charged polyelectrolyte coating prevents sorbing oxidic nanoparticles from both partitioning into the PDMS phase and aggregation at its surface. The results for the TCS/nanoparticle sample show that the polyelectrolyte layer-modified solid phase extracts just the free form of the organic compound and enables dynamic speciation analysis of the nanoparticulate target analyte complex

Single layer and multilayer vacuum-arc coatings based on the nitride TiAlSiYN: composition, structure, properties

International Nuclear Information System (INIS)

Beresnev, V.M.; Litovchenko, S.V.; Nemchenko, U.S.; Srebnyuk, P.A.; Mazilin, B.A.; Sobol, O.V.; Mejlekhov, A.A.; Barmin, A.E.; Serenko, TA.; Pogrebnyak, A.D.; Ivanov, O.N.; Kritsyna, E.V.; Stolbovoj, V.A.; Novikov, V.Yu.; Malikov, L.V.

2017-01-01

Using high-technological vacuum-arc evaporation in the atmosphere of nitrogen with ion bombardment, single- and multilayer coatings based on TiAlSiYN with high mechanical characteristics were obtained: hardness of the coatings reached 49.5 GPa, resistance to wear, with the value of the critical point L_C_5 reaching 184.92 N. The peculiarities of radiation-induced effect at applying bias potential U_b were found: formation of nitride coatings based on fcc metallic lattice with the preferred orientation of crystallites with the texture axis [111], as well as simultaneous growth of hardness. Hardness of both single- and multilayer coatings increases by 40...50% at the increase of U_b from 50 to 200 V. Formation of silicon-containing layers of TiAlSiYN during the deposition contributes to reaching increased hardness, which, in the case of single-layer coating obtained at U_b = -200 V is 49.5 GPa, which corresponds to superhard state. The mechanisms of structure formation, defining the resulting mechanical characteristics of single- and multi-layer coatings based on TiAlSiYN nitride have been discussed.

Analysis of flavor and perfume using an internally cooled coated fiber device.

Science.gov (United States)

Chen, Yong; Begnaud, Frédéric; Chaintreau, Alain; Pawliszyn, Janusz

2007-05-01

A miniaturized internally cooled coated fiber device was applied for the analysis of flavors and fragrances from various matrices. Its integration with a CTC CombiPAL autosampler enabled high throughput for the analysis of analytes in complex matrices that required simultaneous heating of the matrices and cooling of the fiber coating to achieve high extraction efficiency. It was found that up to ten times increase of extraction efficiencies was observed when the device was used to extract flavor compounds in water, even when limited sample temperatures were used to preserve the integrity of target compounds. The extraction of the flavor compounds in water with the device was reproducible, with RSD not larger than 15%. The lower limits of the linear ranges were in the low ppb range, which was about one order of magnitude smaller than those obtained with the commercialized 100 microm PDMS fibers. Exhaustive extraction of some perfume ingredients from a complex matrix (shampoo) was realized. All achieved recoveries were not less than 80%. The repeatability of the extraction of the perfume compounds from shampoo was better than 10%. The linear ranges were about 1-3000 microg/g, and the LOD was about 0.2-1 microg/g. The automated internally cooled coated fiber device was demonstrated to be a powerful sample preparation tool in flavor and fragrance analysis.

Fracture of niobium-base silicide coated alloy

International Nuclear Information System (INIS)

Davydova, A.D.; Zotov, Yu.P.; Ivashchenko, O.V.; Kushnareva, N.P.; Yarosh, I.P.

1990-01-01

Mechanical properties and character of fracture of Nb-W-Mo-Zr-C alloy composition with complex by composition and structure silicide coating under different states of stage-by-stage coating are studied. Structural features, character of fracture from ductile to quasibrittle transcrystalline one and, respectively, the composition plasticity level are defined by interrelation of fracture processes in coating, matrix plastic flow and possibility and way of stress relaxation on their boundary

Reflection/suppression coatings for 900 - 1200 A radiation

Science.gov (United States)

Edelstein, Jerry

1989-01-01

The design and performance of multiple-layer, selective-reflection, selective-suppression coatings for the 900 - 1200 A band are described. These coatings are designed to optimize both high reflectivity at a desirable wavelength and low reflectivity at an undesirable wavelength. The minimum structure for a selective coating consists of a thin metal or metal oxide layer (50 - 150 A thickness) over an aluminum substrate protected with a semi-transparent dielectric (100 - 1000 A thickness). Predicted coating performance is strongly effected by varying the layer combination and thickness. A graphical method of optimizing the coating layer structure is developed. Aluminum, silicon, their oxides, and gold have been investigated as coating layer materials. A very simple coating with a 1026 to 1216 A reflectivity ratio greater than 100 was fabricated. Such reflection/suppression coatings may be of great utility to spaceborne EUV spectrographs.

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

Plasma spraying of hard magnetic coatings based on Sm-Co alloys

International Nuclear Information System (INIS)

KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F. Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Saunin, V N; KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F. Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Telegin, S V

2015-01-01

Our research is focused on the formation of hard magnetic coatings by plasma spraying an arc-melted Sm-Co powder. We have studied basic magnetic characteristics depending on the components ratio in the alloy. A sample with a 40 wt.% Sm coating exhibits the highest coercive force (63 kOe) as compared to near-to-zero coercive force in the starting powder. X-ray structure analysis of the starting alloy and the coating reveals that the amount of SmCo 5 phase in the sprayed coating increases occupying up to 2/3 of the sample. We have also studied temperature dependence of the coating and have been able to obtain plasma sprayed permanent magnets operating within the temperature range from -100 to +500 °C. The technique used does not involve any additional thermal treatment and allows a coating to be formed right on the magnetic conductor surface irrespective of the conductor geometry

Structure and properties of the combined protective coatings on the basis of nickel deposited substrates of steel

International Nuclear Information System (INIS)

Ruzimov, Sh.M.; Pogrebnjak, A.D.; Kuroda, S.; Alonseva, D.L.; Kolisnichenko, O.V.

2006-01-01

Full text: Recently alongside with traditional technologies of surface hardenings like, chemical-technical processing and other highly concentrated sources of heating as plasma jet and electronic beam are more actively used. One of the most perspective and modern methods of reception of materials are the combined methods of processing of materials. The results of structure and element composition of the coatings researches conducted the plasma-detonation method on a substrate from steel are submitted. In practice plasma powder coatings from nickel alloys are widely applied. As coatings from a powder on the basis of nickel: PG-10 N-01 (Ni- the base; Cr -14-20%; Fe -7%; Si - 4,3%; B - 3,3%; C -0,8%;), PGAN-33 (Ni-the base; Cr -24%; Mo -4%; Si -2%; B -2%; W -1%) and PG-19 N-01 (Ni- the base; Cr-8-14%; Fe-5%; Si-1,2-3,2%; B-2,3%; C-0,5%;) are used. After drawing coatings from powders PG-10 N-01 and PGAN-33 a part of samples have melted off high-current electron beam in two modes: soft and rigid. Under high-temperature influence electron melting plastic inter metalloid connections Cr 3 Ni 2 and Cr B are formed in a surface of a coating. Coatings from PG-19 N-01 are deposited either preliminary heated, or as taken a cold substrate for some passes. Repeated melting of coating surfaces was conducted by a pulse plasma jet without adding of a powder in it. In this work to study coating surfaces and their transversal cross sections, we applied XRD and SEM with a microanalysis. Also we measured micro-hardness and wear. The studies demonstrated that the plasma-detonation technology could provide the formation of the coatings with a dense adhesion to a substrate. It is shown that additional processing of a coating by a plasma jet result in change of a shape of a surface, redistribution of elements to reduction the size of grains. In turn it considerably changes mechanical properties of coatings. (author)

Preparation of aluminide coatings on the inner surface of tubes by heat treatment of Al coatings electrodeposited from an ionic liquid

International Nuclear Information System (INIS)

Xue, Dongpeng; Chen, Yimin; Ling, Guoping; Liu, Kezhao; Chen, Chang’an; Zhang, Guikai

2015-01-01

Highlights: • Al coating is prepared on the inner surface of one-meter tube. • Al coating shows good adherence to the substrate. • The thickness of Al coating is uniform along the tube. • Aluminide coating is obtained by heat treating Al coating. • Structure of aluminide coating is regulated by different thickness of Al coating. - Abstract: Aluminide coatings were prepared on the inner surface of 316L stainless steel tubes with size of Ø 12 mm × 1000 mm by heat-treating Al coatings electrodeposited from AlCl 3 -1-ethyl-3-methyl-imidazolium chloride (AlCl 3 –EMIC) ionic liquid at room temperature. Studies on the electrolytic etching pretreatment of stainless tubes before Al coating electrodeposition were carried out. The Al coating showed good adherence to the substrate after electrolytic etching at 10 mA/cm 2 for 10 min. The thickness of Al coatings was uniform along the tube. The structure of prepared aluminide coatings can be regulated by different thickness of Al coating. The outer layer of aluminide coatings was FeAl, Fe 2 Al 5 and FeAl 3 for the samples of 1-μm, 5-μm and 10-μm thick Al coatings, respectively.

Flame retardancy and thermal degradation of cotton textiles based on UV-curable flame retardant coatings

Energy Technology Data Exchange (ETDEWEB)

Xing, Weiyi [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China); Jie, Ganxin [State Key Laboratory of Environmental Adaptability for Industrial Products, China National Electric Apparatus Research Institute, Guangzhou 510300 (China); Song, Lei; Hu, Shuang; Lv, Xiaoqi; Wang, Xin [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzai Road, Hefei, Anhui 230026 (China); Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China)

2011-01-20

The flame retardant coatings were prepared through UV-curable technique using tri(acryloyloxyethyl) phosphate (TAEP) and triglycidyl isocyanurate acrylate (TGICA). Results from FTIR-ATR spectroscopy and scanning electron microscopy (SEM) showed that flame retardant coatings were successfully coated onto the surface of cotton fabrics. The flame retardancy of the treated fabrics was studied by Micro-scale Combustion Calorimeter (MCC) and limited oxygen index (LOI). The cottons coated flame retardant coatings had the lower peak heat release rate (PHRR), heat release capacity (HRC), total heat of combustion (THC) and higher LOI value compared with untreated cotton. The results from TGA test showed that the flame retardant coatings lowered the decomposition temperature of treated fabric. The thermal decomposition of cottons was monitored by real time FTIR analysis and thermogravimetric analysis/infrared spectrometry (TGA-IR). The enhanced flame retardant action might be caused by thermal decomposition of TAEP structure, producing acidic intermediates, which could react with fabrics to alter its thermal decomposition process.

The structure and the photocatalytic activity of titania based nanotube and nanofiber coatings

Energy Technology Data Exchange (ETDEWEB)

Radtke, A., E-mail: aradtke@umk.pl [Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, 87-100 Toruń (Poland); Piszczek, P.; Topolski, A.; Lewandowska, Ż. [Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, 87-100 Toruń (Poland); Talik, E. [A. Chełkowski Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Andersen, I. Hald; Nielsen, L. Pleth [Tribology Centre, Danish Technological Institute, Kongsvang Allé 29, 8000 Aarhus C (Denmark); Heikkilä, M.; Leskelä, M. [Centre of Excellence, Laboratory of Inorganic Chemistry, Chemistry Department, Faculty of Science, University of Helsinki, A.I. Virtasen aukio 1, FI-00014 (Finland)

2016-04-15

Graphical abstract: - Highlights: • The photoactivity of TNT and TNF has been quantified by two different methods. • The influence of the TNT and TNF structure on their photoactivity was studied. • The photoactivity comparison of TNT and TNF was carried out. • TNF coatings show higher photoactivity in comparison to TNT. - Abstract: The photocatalytic activity of TiO{sub 2} based nanotube (TNT) and nanofiber (TNF) coatings has been investigated, in correlation to their structure, morphology, specific surface area, acidity and the amount of surface H{sub 2}O molecules and −OH groups. Characterization of these materials was carried out using grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The photocatalytic activity has been quantified by two different methods, based on the photodegradation of methylene blue (the pattern of water-soluble organic pollutant) and acetone (the pattern of volatile organic pollutant), respectively. Results of our investigations revealed that TNF coatings were significantly more active in case of both photodegradation processes in air and water, as compared to TNT, even if the specific surface area of TNF films was smaller than the adequate surface area of TNT. The microstructure of produced materials, the amount of adsorbed −OH groups and H{sub 2}O molecules located on the surface of materials, and the acidity of the surface, were the main factors which affect their photoactivity. Photocatalytic properties of tubular and porous TiO{sub 2}-based materials are the resultant of the compilation of individual factors impact and any of them cannot be neglected.

The structure and the photocatalytic activity of titania based nanotube and nanofiber coatings

International Nuclear Information System (INIS)

Radtke, A.; Piszczek, P.; Topolski, A.; Lewandowska, Ż.; Talik, E.; Andersen, I. Hald; Nielsen, L. Pleth; Heikkilä, M.; Leskelä, M.

2016-01-01

Graphical abstract: - Highlights: • The photoactivity of TNT and TNF has been quantified by two different methods. • The influence of the TNT and TNF structure on their photoactivity was studied. • The photoactivity comparison of TNT and TNF was carried out. • TNF coatings show higher photoactivity in comparison to TNT. - Abstract: The photocatalytic activity of TiO_2 based nanotube (TNT) and nanofiber (TNF) coatings has been investigated, in correlation to their structure, morphology, specific surface area, acidity and the amount of surface H_2O molecules and −OH groups. Characterization of these materials was carried out using grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The photocatalytic activity has been quantified by two different methods, based on the photodegradation of methylene blue (the pattern of water-soluble organic pollutant) and acetone (the pattern of volatile organic pollutant), respectively. Results of our investigations revealed that TNF coatings were significantly more active in case of both photodegradation processes in air and water, as compared to TNT, even if the specific surface area of TNF films was smaller than the adequate surface area of TNT. The microstructure of produced materials, the amount of adsorbed −OH groups and H_2O molecules located on the surface of materials, and the acidity of the surface, were the main factors which affect their photoactivity. Photocatalytic properties of tubular and porous TiO_2-based materials are the resultant of the compilation of individual factors impact and any of them cannot be neglected.

Simulation of the coating film appearance for spray application

OpenAIRE

Seeler, Fabian; Hager, Christian; Schneider, Matthias; Tiedje, Oliver

2015-01-01

The coating film topography depends on the substrate structure, the application parameters and the coating material’s levelling properties. Substrates consisting of several materials with different surface structures and differently inclined areas make a homogenous coating film structure difficult. By means of simulations, the paint film structure is intended to be controlled so that the theoretical optimum is reached and the experimental effort can be reduced. The focus is on spray applicati...

The structurally effect of surface coated rhamnogalacturonan I on response of the osteoblast-like cell line SaOS-2

DEFF Research Database (Denmark)

Svava, Rikke; Gurzawska, Katarzyna; Yihau, Yu

2014-01-01

Osseointegration is important when implants are inserted into the bone and can be improved by biochemical surface coating of the implant. In this paper enzymatically modified rhamnogalacturonan I (RG-I) from apple and lupin was used for biochemical coating of aminated surfaces and the importance...... remove small fragments of galacturonic acid (GalA) and binding studies showed that the purity of the RG-I molecules was important for the quality of the coating. The structure of RG-I and osteoblast-like cells' viability were positively correlated so that high content of 1,4-linked galactose (Gal...

Study of Plasma Electrolytic Oxidation Coatings on Aluminum Composites

Directory of Open Access Journals (Sweden)

Leonid Agureev

2018-06-01

Full Text Available Coatings, with a thickness of up to 75 µm, were formed by plasma electrolytic oxidation (PEO under the alternating current electrical mode in a silicate-alkaline electrolyte on aluminum composites without additives and alloyed with copper (1–4.5%. The coatings’ structure was analyzed by scanning electron microscopy, X-ray microanalysis, X-ray photoelectron spectroscopy, nuclear backscattering spectrometry, and XRD analysis. The coatings formed for 60 min were characterized by excessive aluminum content and the presence of low-temperature modifications of alumina γ-Al2O3 and η-Al2O3. The coatings formed for 180 min additionally contained high-temperature corundum α-Al2O3, and aluminum inclusions were absent. The electrochemical behavior of coated composites and uncoated ones in 3% NaCl was studied. Alloyage of aluminum composites with copper increased the corrosion current density. Plasma electrolytic oxidation reduced it several times.

In situ synthesis of hydroxyapatite coating by laser cladding.

Science.gov (United States)

Wang, D G; Chen, C Z; Ma, J; Zhang, G

2008-10-15

HA bioceramic coatings were synthesized on titanium substrate by laser cladding using cheap calcium carbonate and calcium hydrogen phosphate. The thermodynamic condition for synthesizing HA was calculated by software Matlab 5.0, the microstructure and phase analysis of laser clad HA bioceramic coatings were studied by electron probe microanalyser (EPMA), X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The theoretical results show that the Gibbs free enthalpy for the synthesis of HA phase is satisfied, and the presence of HA phase in the clad coatings was then further verified by XRD and the selected area diffraction patterns. When the laser power is 600W and the scanning speed is 3.5mm/s, the compact HA bioceramic coatings were obtained, which have cellular dendritic structure and consist of the phases of HA, alpha-Ca(2)P(2)O(7), CaO and CaTiO(3).

Composite structure of ZnO films coated with reduced graphene oxide: structural, electrical and electrochemical properties

Science.gov (United States)

Shuai, Weiqiang; Hu, Yuehui; Chen, Yichuan; Hu, Keyan; Zhang, Xiaohua; Zhu, Wenjun; Tong, Fan; Lao, Zixuan

2018-02-01

ZnO films coated with reduced graphene oxide (RGO-ZnO) were prepared by a simple chemical approach. The graphene oxide (GO) films transferred onto ZnO films by spin coating were reduced to RGO films by two steps (exposed to hydrazine vapor for 12 h and annealed at 600 °C). The crystal structures, electrical and photoluminescence properties of RGO-ZnO films on quartz substrates were systematically studied. The SEM images illustrated that RGO layers have successfully been coated on the ZnO films very tightly. The PL properties of RGO-ZnO were studied. PL spectra show two sharp peaks at 390 nm and a broad visible emission around 490 nm. The resistivity of RGO-ZnO films was measured by a Hall measurement system, RGO as nanofiller considerably decrease the resistivity of ZnO films. An electrode was fabricated, using RGO-ZnO films deposited on Si substrate as active materials, for super capacitor application. By comparison of different results, we conclude that the RGO-ZnO composite material couples possess the properties of super capacitor. Project supported by the National Natural Science Foundation of China (Nos. 61464005, 51562015), the Natural Science Foundation of Jiangxi Province (Nos. 20143ACB21004, 20151BAB212008, 20171BAB216015), the Jiangxi Province Foreign Cooperation Projects, China (No. 20151BDH80031), the Leader Training Object Project of Major Disciplines Academic and Technical of Jiangxi Province (No. 20123BCB22002), and the Key Technology R & D Program of the Jiangxi Provine of Science and Technology (No. 20171BBE50053).

Application of neutron activation analysis to the corrosion study of gold coated studs used for piercing ears

International Nuclear Information System (INIS)

Saiki, M.; Rogero, S.O.; Costa, I.; Correa, O.V.; Higa, O.Z.

1998-01-01

Complete text of publication follows. Gold is known as a metal having little or no toxicity and it has been widely used for coating studs for ear piercing. However, for some people gold coated studs have caused serious allergy and inflammation problems. After piercing, the studs are usually kept in the ear lobes for at least one week, and during this period the stud surfaces in contact with the body fluids have caused swelling, pain and redness of the skin. Consequently, it is of great interest to evaluate if elements from the metallic substrate underneath the gold coatings migrate to the body fluids due to the corrosion and the presence of defects in gold coatings. The solutions for corrosion test were obtained by placing the gold coated studs in contact with the solutions of NaCl and of culture medium. Elemental analyses of these solutions by radioanalytical method of neutron activation analysis indicated the occurrence of substrate corrosion since the elements Cr, Fe, Ni and Zn were found in these solutions. These elements are substrate material components of alloys used to make the studs and they were quantified by X-ray fluorescence analysis. The defects of the coatings were also detected by scanning electron microscopy and energy dispersive spectroscopy analysis of the gold coated studs before and after the corrosion tests. Cytotoxicity studies indicated that after corrosion test the solution used was toxic in the culture cell assay. Among the elements quantified in the test solutions, Ni is considered responsible for most of allergic reactions. Results obtained in this work indicated the necessity to improve quality control of the coating process of studs and in the appropriate choice of material used as substrate

Microstructural Analysis of TiAl x N y O z Coatings Fabricated by DC Reactive Sputtering

Science.gov (United States)

García-González, L.; Hernández-Torres, J.; Flores-Ramírez, N.; Martínez-Castillo, J.; García-Ramírez, P. J.; Muñoz-Saldaña, J.; Espinoza-Beltrán, F. J.

2009-02-01

TiAl x N y O z coatings were prepared by DC reactive sputtering on AISI D2 tool steel substrates, using a target of Ti-Al-O fabricated from a mixture of powders of Ti (22.60 wt.%), Al (24.77 wt.%), and O (52.63 wt.%). The coatings were deposited on substrates at room temperature in a reactive atmosphere of nitrogen and argon under a pressure of 8.5 × 10-3 mbar. X-ray diffraction, electron dispersive spectroscopy, Raman scattering, and nanoindentation techniques were employed to investigate the coatings. The results show that the increment in the nitrogen flow affects the structure and the mechanical properties of the coatings. The sample with the lowest nitrogen flow presented the highest hardness (10.5 GPa) and the Young’s modulus (179.5 GPa). The hardness of the coatings TiAl x N y O z as a function of crystalline grain size shows a behavior consistent with the Hall-Petch relation.

Neutron irradiation and high temperature effects on amorphous Fe-based nano-coatings on steel - A macroscopic assessment

Science.gov (United States)