WorldWideScience

Sample records for spray-fused powder coatings

  1. Low Temperature Powder Coating

    Science.gov (United States)

    2011-02-09

    of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) • Legacy primers contain hexavalent chrome • Conventional powder coatings...coatings both in laboratory and field service evaluations • LTCPC allows environmental cost reductions through VOC/HAP elimination and hexavalent ... chrome reduction. • The LTCPC process greatly shortens the coating operation (LTCPC cures much more rapidly then conventional wet coatings) resulting in

  2. POWDER COAT APPLICATIONS

    Science.gov (United States)

    The report discusses an investigation of critical factors that affect the use of powder coatings on the environment, cost, quality, and production. The investigation involved a small business representative working with the National Defense Center for Environmental Excellence (ND...

  3. Dry and coating of powders

    International Nuclear Information System (INIS)

    Alonso, M.; Alguacil, F. J.

    1999-01-01

    This paper presents a review on the mixing and coating of powders by dry processes. The reviews surveys fundamental works on mixture characterization (mixing index definitions and sampling techniques), mixing mechanisms and models, segregation with especial emphasis on free-surface segregation, mixing of cohesive powders and interparticle forces, ordered mixing (dry coating) including mechanism, model and applications and mixing equipment selection. (Author) 180 refs

  4. Coating of ceramic powders by chemical vapor deposition techniques (CVD)

    International Nuclear Information System (INIS)

    Haubner, R.; Lux, B.

    1997-01-01

    New ceramic materials with selected advanced properties can be designed by coating of ceramic powders prior to sintering. By variation of the core and coating material a large number of various powders and ceramic materials can be produced. Powders which react with the binder phase during sintering can be coated with stable materials. Thermal expansion of the ceramic materials can be adjusted by varying the coating thickness (ratio core/layer). Electrical and wear resistant properties can be optimized for electrical contacts. A fluidized bed reactor will be designed which allow the deposition of various coatings on ceramic powders. (author)

  5. Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

    International Nuclear Information System (INIS)

    Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

    1979-01-01

    Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

  6. Fluidization bed coating of copper bars with epoxy powder

    OpenAIRE

    Soh, Chiaw Min

    2014-01-01

    Fluidized bed coating (FBC) is a process where preheated material is dipped into a flowing liquid bed of powder. Although FBC has existed for more than half a century, however there is little knowledge about the fluidized bed design that gives excellent fluidization quality as well as reducing powder entrainment. The objectives of this thesis are to investigate the effect of two different types of distributor with different pressure drop on powder coating, hydrodynamics of fluidized bed coati...

  7. Tuning roughness and gloss of powder coating paint by encapsulating the coating particles with thin Al

    NARCIS (Netherlands)

    Valdesueiro, David; Hettinga, Hans; Drijfhout, Jan Pieter; Lips, Priscilla; Meesters, G.M.H.; Kreutzer, M.T.; van Ommen, J.R.

    2017-01-01

    In this work, we report a method to change the surface finish of a standard polyester-based powder coating paint, from gloss to matt, by depositing ultrathin films of Al2O3 on the powder coating particles. The coating experiments were performed in a fluidized bed reactor at

  8. Corrosion issues of powder coated AA6060 aluminium profiles

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl

    2015-01-01

    In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

  9. Effect of surface coating with magnesium stearate via mechanical dry powder coating approach on the aerosol performance of micronized drug powders from dry powder inhalers.

    Science.gov (United States)

    Zhou, Qi Tony; Qu, Li; Gengenbach, Thomas; Larson, Ian; Stewart, Peter J; Morton, David A V

    2013-03-01

    The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency.

  10. Gas-thermal coating of powdered materials. Communication 2

    International Nuclear Information System (INIS)

    Ermakov, S.S.

    1986-01-01

    This paper investigates the microstructure, microhardness, chemical composition of the transition zone, and also the strength characteristics of gas-thermal coatings including their adhesive power to the substrate (iron brand NC 100.24) and the residual stresses in the coatings. The microstructure of the transition zone was investigated; it was established that on the side of the substrate its density is greater than the mean density of both types of coating. It is shown that the porosity of the substrate has a competing effect on the thermal interaction of materials. Discovered regularities lead to the conclusion that the process of gas-thermal coating of powdered materials is more effective than when compact materials are coated; most effective is the combination of gas-thermal coating with processes of heat treatment of powder-metallurgy products

  11. Powder ink coatings in nuclear medicine and nuclear technology

    International Nuclear Information System (INIS)

    Kunze, S.; Schlautek, H.

    1996-01-01

    Powder ink coatings are being used more and more frequently to protect the surfaces of movable objects of metal, such as machines, equipment, furniture, shelves, because this solvent-free coating technique, which produces almost no residues, helps to keep the environment clean. The white and grey baking coatings so far tested for decontaminability are presented in the article. Powder ink coatings of different shades and with different binders were tested for their ability to meet future standards. All systems under examination demonstrated excellent decontaminability before and after gamma exposure to 0.3 MGy. The same performance was obtained also after exposure to 3 MGy (ten times the level required for coatings in nuclear installations according to DIN 55991 Part 1), with the exception of one polyester metallic coating. After having been exposed to chemicals and decontamination solutions, all specimens showed only permissible discoloration. (orig.) [de

  12. Suspension plasma sprayed composite coating using amorphous powder feedstock

    International Nuclear Information System (INIS)

    Chen Dianying; Jordan, Eric H.; Gell, Maurice

    2009-01-01

    Al 2 O 3 -ZrO 2 composite coatings were deposited by the suspension plasma spray process using molecularly mixed amorphous powders. X-ray diffraction (XRD) analysis shows that the as-sprayed coating is composed of α-Al 2 O 3 and tetragonal ZrO 2 phases with grain sizes of 26 nm and 18 nm, respectively. The as-sprayed coating has 93% density with a hardness of 9.9 GPa. Heat treatment of the as-sprayed coating reveals that the Al 2 O 3 and ZrO 2 phases are homogeneously distributed in the composite coating

  13. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    Energy Technology Data Exchange (ETDEWEB)

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  14. A dual response surface optimization methodology for achieving uniform coating thickness in powder coating process

    Directory of Open Access Journals (Sweden)

    Boby John

    2015-09-01

    Full Text Available The powder coating is an economic, technologically superior and environment friendly painting technique compared with other conventional painting methods. However large variation in coating thickness can reduce the attractiveness of powder coated products. The coating thickness variation can also adversely affect the surface appearance and corrosion resistivity of the product. This can eventually lead to customer dissatisfaction and loss of market share. In this paper, the author discusses a dual response surface optimization methodology to minimize the thickness variation around the target value of powder coated industrial enclosures. The industrial enclosures are cabinets used for mounting the electrical and electronic equipment. The proposed methodology consists of establishing the relationship between the coating thickness & the powder coating process parameters and developing models for the mean and variance of coating thickness. Then the powder coating process is optimized by minimizing the standard deviation of coating thickness subject to the constraint that the thickness mean would be very close to the target. The study resulted in achieving a coating thickness mean of 80.0199 microns for industrial enclosures, which is very close to the target value of 80 microns. A comparison of the results of the proposed approach with that of existing methodologies showed that the suggested method is equally good or even better than the existing methodologies. The result of the study is also validated with a new batch of industrial enclosures.

  15. Electrochemical behaviors of wax-coated Li powder/Li 4Ti 5O 12 cells

    Science.gov (United States)

    Park, Han Eol; Seong, Il Won; Yoon, Woo Young

    The wax-coated Li powder specimen was effectively synthesized using the drop emulsion technique (DET). The wax layer on the powder was verified by SEM, Focused Ion Beam (FIB), EDX and XPS. The porosity of a sintered wax-coated Li electrode was measured by linear sweep voltammetry (LSV) and compared with that of a bare, i.e., un-coated Li electrode. The electrochemical behavior of the wax-coated Li powder anode cell was examined by the impedance analysis and cyclic testing methods. The cyclic behavior of the wax-coated Li powder anode with the Li 4Ti 5O 12 (LTO) cathode cell was examined at a constant current density of 0.35 mA cm -2 with the cut-off voltages of 1.2-2.0 V at 25 °C. Over 90% of the initial capacity of the cell remained even after the 300th cycle. The wax-coated Li powder was confirmed to be a stable anode material.

  16. Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

    Energy Technology Data Exchange (ETDEWEB)

    Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

    2018-02-06

    The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance against corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.

  17. Advanced Powder Coating Systems for Military Applications

    Science.gov (United States)

    2011-05-01

    UVCPC • Conclusions • DoD spends billions of dollars annually on protective organic coatings – Hexavalent chrome primer use still widespread – Contains...Elimination of Hazardous Air Pollutants (HAP) • Reduction/Elimination of ESOH Concerns – Elimination of hexavalent chromium – Elimination of free...production and release; hexavalent chromium; free isocyanates; up to 72 hrs “dry to fly” time Longer cure times than traditional primers and

  18. Preparation of sustained release capsules by electrostatic dry powder coating, using traditional dip coating as reference.

    Science.gov (United States)

    Yang, Yan; Shen, Lian; Yuan, Feng; Fu, Hui; Shan, Weiguang

    2018-05-30

    Lately, a great deal of attention is being paid to capsule coating, since the coat protects active pharmaceutical ingredients (APIs) from damage, as is in the case of tablet and pellet. However, moisture and heat sensitivity of gelatin shells make it challenging to coat capsules using the conventional aqueous coating techniques. In an effort to overcome this challenge, the present study aims to coat capsules using two different coating techniques: electrostatic dry powder coating (EDPC) and dip coating (DC). Both capsule coatings and free films were prepared by these two coating techniques, and the effects of coating formulations and processing conditions on the film quality were investigated. The corresponding drug in vitro release and mechanisms were characterized and compared. The results of dissolution tests demonstrated that the drug release behavior of both EDPC and DC coated capsules could be optimized to a sustained release of 24 h, following the Fick's diffusion law. The results of this study suggest that EDPC method is better than DC method for coating capsules, with respect to the higher production efficiency and better stability, indicating that this dry coating technology has promised in gelatin capsule coating applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Laser fabrication nanocrystalline coatings using simultaneous powders/wire feed

    Science.gov (United States)

    Li, Jianing; Zhai, Tongguang; Zhang, Yuanbin; Shan, Feihu; Liu, Peng; Ren, Guocheng

    2016-07-01

    Laser melting deposition (LMD) fabrication is used to investigate feasibilty of simultaneously feeding TC17 wire and the Stellite 20-Si3N4-TiC-Sb mixed powders in order to increase the utilization ratio of materials and also quality of LMD composite coatings on the TA1 substrate. SEM images indicated that such LMD coating with metallurgical joint to substrate was formed free of the obvious defects. Lots of the ultrafine nanocrystals (UNs) were produced, which distributed uniformly in some coating matrix location, retarding growth of the ceramics in a certain extent; UNs were intertwined with amorphous, leading the yarn-shape materials to be produced. Compared with substrate, an improvement of wear resistance was achieved for such LMD coating.

  20. Energy efficiency opportunities within the powder coating industry

    Energy Technology Data Exchange (ETDEWEB)

    Osbeck, Sofie; Bergek, Charlotte; Klaessbo, Anders (Swerea IVF AB, Moelndal (Sweden)), e-mail: anders.klassbo@swerea.se; Thollander, Patrik; Rohdin, Patrik (Dept. of Management and Engineering, Linkoeping Univeristy, Linkoeping (Sweden)); Harvey, Simon (Dept. of Energy and Environment, Chalmers Univ. of Technology, Goeteborg (Sweden))

    2011-06-15

    A new challenge to reduce energy usage has emerged in Swedish industry because of increasing energy costs. Energy usage in the Swedish powder coating industry is about 525 GWh annually. This industry has a long and successful record of working towards reduced environmental impact. However, they have not given priority to energy saving investments. Electricity and LPG, for which end-user prices are predicted to increase by as much as 50 - 60% by 2020, are the main energy carriers used in the plants. This paper presents the results of two detailed industrial energy audits conducted with the aim of quantifying the energy efficiency potential for the Swedish powder coating industry. Energy auditing and pinch analysis methods were used to identify possible energy housekeeping measures and heat exchanging opportunities. The biggest users of energy within the plants are the cure oven, drying oven and pre-treatment units. The energy use reduction by the housekeeping measures is 8 - 19% and by thermal heat recovery an additional 8 - 13%. These measures result in an average energy cost saving of 25% and reduction of carbon dioxide emissions of 30%. The results indicate that the powder coating industry has a total energy efficiency potential of at least 20%

  1. Electrostatic powder coatings of pristine graphene: A new approach for coating of granular and fibril substrates

    Science.gov (United States)

    Nine, Md J.; Kabiri, Shervin; Tung, Tran Thanh; Tran, Diana N. H.; Losic, Dusan

    2018-05-01

    The use of pristine graphene (pG) based on solution processed coating technologies is often limited by their poor dispersibility in water and organic solvents which prevents to achieve the best performing properties of pG in coating applications. To address these limitations, we developed a dispersant-free coating approach of pG based on their intrinsic solid-lubricity and interlayer electrostatic interactions. The "rotating drum" method was established to provide suitable conditions for electrostatic deposition of pG-powder which is demonstrated on two model substrates with granular and fibril morphologies (urea and acrylic fibers) to improve their physical and electrical properties. The results showed that the pG coating enables to minimize moisture induced caking tendency of commercial urea prills at a relative humidity (RH) of 85% (higher than critical humidity) exhibiting greater moisture rejection ability (∼2 times higher than uncoated urea) and to improve their anti-abrasive properties. The pG-powder coating applied on nonconductive acrylic fibers provides a stable conductive layer (∼0.8 ± 0.1 kΩ/sq) which made them suitable for using in wearable electronics, sensors and electromagnetic interference (EMI) shielding. The developed coating method for pG-powder based on "rotating drum" is generic, simple, eco-friendly, low-cost, and scalable for broad range of coating applications.

  2. Tough-coated hard powders for hardmetals of novel properties

    International Nuclear Information System (INIS)

    Toth, R.E.; Smid, I.; Kladler, G.; Korb, G.; Sherman, A.; Ettmayer, P.

    2001-01-01

    The properties and performance of conventional materials and composites are constrained by solubility limits, diffusion coefficients, and compatibility of physical and chemical constituent properties in their phase equilibria. To escape these limits, ingenious ways of combining strength, toughness, and wear resistance by way of various coatings and laminations have been devised. These coated tools are systematically discarded after only about 10 % of their wear tolerance has been used. Tough-coated hard powders (TCHP), patented by EnDurAloy (USA), are hard refractory particles CVD coated with nanolayers of WC and Co. Consolidation of TCHP creates an engineered homogeneous cellular structure whose interconnected tough WC-Co 'shells' each contain a wear-resistant core (e.g., TiN). In TCHP's, the coating is throughout the tool, not only on the surface, combining the strength, heat resistance, and toughness of cemented carbides with the chemical and abrasion wear resistance of harder materials. As wear progresses, new wear-resistant material continuously replaces the working surfaces and edges of the tool until its geometry reaches its maximum limits. TCHP tools are then reusable many times. Specific coating and consolidation processes, characterization of compacts, and test comparisons with conventional materials are discussed. (author)

  3. Evaluation of the Commercial off-the-shelf (COTS) Low Temperature Powder Coating (LTPC)

    Science.gov (United States)

    2017-11-15

    CONTRACT NUMBER: FA8532-17-C-0008 (CDRL A001) Evaluation of the Commercial off- the-shelf (COTS) Low Temperature Powder Coating (LTPC...3 Evaluation of the COTS LTPC (CDRL A001) BATTELLE 1 1.0 Introduction...primers in traditional coating systems is costly, time consuming , and represents a risk to health, safety, and the environment. Powder coatings

  4. Preparation and microwave shielding property of silver-coated carbonyl iron powder

    International Nuclear Information System (INIS)

    Cao, Xiao Guo; Ren, Hao; Zhang, Hai Yan

    2015-01-01

    Highlights: • The silver-coated carbonyl iron powder is prepared by the electroless plating process. • The silver-coated carbonyl iron powder is a new kind of conductive filler. • The reflection and absorption dominate the shielding mechanism of the prepared powder. • Increasing the thickness of electroconductive adhesive will increase the SE. - Abstract: Electroless silver coating of carbonyl iron powder is demonstrated in the present investigation. The carbonyl iron powders are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the coating process. The relatively uniform and continuous silver coating is obtained under the given coating conditions. In this paper, the electromagnetic interference (EMI) shielding mechanism of the silver-coated carbonyl iron powder is suggested. The reflection of silver coating and absorption of carbonyl iron powder dominate the shielding mechanism of the silver-coated carbonyl iron powder. The silver-coated carbonyl iron powders are used as conductive filler in electroconductive adhesive for electromagnetic interference shielding applications. The effect of the thickness of electroconductive adhesive on the shielding effectiveness (SE) is investigated. The results indicate that the SE increases obviously with the increase of the thickness of electroconductive adhesive. The SE of the electroconductive adhesive with 0.35 mm thickness is above 38 dB across the tested frequency range

  5. Powder addition assessment of manganese residue ceramic matrix coating

    International Nuclear Information System (INIS)

    Conceicao, A.C.R. da; Santos, O.C.; Leao, M.A.

    2016-01-01

    The use of recycled materials in the composition of new products follows the production's worldwide trending, meeting new technological requirements and environmental concerns. This work aims to utilize the residue of manganese dust on ceramic mass for the production of ceramic coating. The raw materials were characterized by both x-ray fluorescence and diffraction. The powder residue added to clay in the percentage of 0%, 5%, 10% and 15% (measured in weight) was compressed by a uniaxial pressing of 30MPa and the sintering temperatures were 900°, 1000° and 1100°. The samples were analysed in relation to flexural strength, bulk density, water absorption and linear shrinkage. The microstructural variation was also analysed by x-ray diffraction and electron microscopy. The results showed that there is a viability for the production of porcelain ceramic coating (A3 and A4 formulations) and stoneware (A2 formulation) according to the specification of technical standards. author)

  6. Characterization for coating processes of imidazole powders using an ultrasonic atomizer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Sik; Kim, Jun Ki [Korea Institute of Industrial Technology, Incheon (Korea, Republic of); Kim, Mok Soon [Inha University, Incheon (Korea, Republic of); Lee, Jong Hyun [Seoul National University, Seoul (Korea, Republic of)

    2010-01-15

    Imidazole-curing accelerator powders were coated with stearic acid to increase the pot life of anisotropic conductive adhesive (ACA) formulations. To accomplish an efficient coating process, the coating was tested using an ultrasonic atomizer after mixing imidazole powders with a molten coating agent. Design of experiments analysis was organized to elucidate the effect of process parameters and to determine the most crucial parameter. The final formulation incorporating well-processed imidazole loaded powders indicated longer pot life, higher shear strength, and excellent highly accelerated stress test (HAST) reliability. Results show that the coating process using an ultrasonic atomizer is effective in increasing the pot life of ACA formulations

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

    OpenAIRE

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

    2016-01-01

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

  8. Influence of the Addition of Montmorillonite in an Epoxy Powder Coating Applied on Carbon Steel

    OpenAIRE

    Piazza,Diego; Baldissera,Alessandra Fiorini; Kunst,Sandra Raquel; Rieder,Ester Schmidt; Scienza,Lisete Cristine; Ferreira,Carlos Arthur; Zattera,Ademir José

    2015-01-01

    AbstractPolymer coatings have been used for the corrosion protection of metal surfaces acting as a physical barrier against several corroding media. In spite of the good efficiency of these coatings their resistance is limited due to the presence of localized defects which give place to localized corrosion. Aiming to improve the barrier properties of these coatings this work has proposed the use of nanocomposites as powder coatings based on a standard formulation of a commercial powder varnis...

  9. Synthesis and Characterization of Calcium Phosphate Powders for Biomedical Applications by Plasma Spray Coating

    OpenAIRE

    Sasidharan Pillai, Rahul

    2015-01-01

    This PhD work mainly focus on the synthesis and characterization of calcium phosphate powders for plasma spray coating. The preparation of high temperature phase stabilized βTCP and HA/βTCP powders for plasma spray coating applications has been the topic of investigation. Nowadays plasma sprayed coatings are widely used for biomedical applications especially in the dental and orthopaedic implantation field. Previously Ti based alloys were widely used for the orthopaedic and dental implant ap...

  10. Liquid coated melt-spun Nd-Fe-B powders for bonded magnets

    Science.gov (United States)

    Li, D.; Gaiffi, S.; Kirk, D.; Young, K.; Herchenroeder, J.; Berwald, T.

    1999-04-01

    The liquid coating (LC) has been employed to apply epoxy and lubricant over the surface of rapidly solidified Nd-Fe-B powder particles. The LC led to an improvement of physical and magnetic properties for the powders and magnets compared to the dry blending and the encapsulation methods. The LC powders have excellent flowability and can be used for bonded magnets requiring very close tolerances; further bonded magnets made using this powder posses higher strength.

  11. Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

    Directory of Open Access Journals (Sweden)

    Ivan Stojanović

    2018-03-01

    Full Text Available Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispensable solvent emission reduction is the application of powder coatings. This study evaluates the corrosion performance and surface morphology of polyester and epoxy–polyester powder coatings. Electrochemical impedance spectroscopy (EIS, open circuit potential (OCP measurement, salt spray chamber and humidity chamber testing followed by adhesion testing were used to investigate the protective properties of powder coatings. Scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDX was used to analyse the surface morphology and chemical composition, whereas the microstructure and coating uniformity were determined by optical microscope examination. The research revealed a negative influence of coating surface texture on coating thickness and consequently a lack of barrier and adhesion properties. The epoxy–polyester powder coating showed a better performance than the polyester coating. All tested coatings showed uniform structure.

  12. Synthesis of Cu-coated Graphite Powders Using a Chemical Reaction Process

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jun-Ho; Park, Hyun-Kuk; Oh, Ik-Hyun [Korea Institute of Industrial Technology (KITECH), Gwangju (Korea, Republic of); Lim, Jae-Won [Chonbuk National University, Jeonju (Korea, Republic of)

    2017-05-15

    In this paper, Cu-coated graphite powders for a low thermal expansion coefficient and a high thermal conductivity are fabricated using a chemical reaction process. The Cu particles adhere to the irregular graphite powders and they homogeneously disperse in the graphite matrix. Cu-coated graphite powders are coarser at approximately 3-4 μm than the initial graphite powders; furthermore, their XRD patterns exhibit a low intensity in the oxide peak with low Zn powder content. For the passivation powders, the transposition solvent content has low values, and the XRD pattern of the oxide peaks is almost non-existent, but the high transposition solvent content does not exhibit a difference to the non-passivation treated powders.

  13. Assessment of properties thermal sprayed coatings realised using cermet blend powder

    Directory of Open Access Journals (Sweden)

    J. Brezinová

    2014-10-01

    Full Text Available The article deals with the assessment of selected properties of plasma sprayed coatings based on ZrSiO4 doped with different volume fractions of metal dopant (Ni. Mixed powders are cermet blends. Aim of the work consists of verificating the possibility to replace the application of Ni interlayer by adding Ni directly to the ceramic powder and apply them together in a single technological operation. The coatings were studied from point of view of their structure, porosity, adhesion of the coatings in relation to the volume of dopant added and wear resistance. The best properties reached composite coating doped with 12 % Ni.

  14. Direct Iron Coating onto Nd-Fe-B Powder by Thermal Decomposition of Iron Pentacarbonyl

    International Nuclear Information System (INIS)

    Yamamuro, S; Okano, M; Tanaka, T; Sumiyama, K; Nozawa, N; Nishiuchi, T; Hirosawa, S; Ohkubo, T

    2011-01-01

    Iron-coated Nd-Fe-B composite powder was prepared by thermal decomposition of iron pentacarbonyl in an inert organic solvent in the presence of alkylamine. Though this method is based on a modified solution-phase process to synthesize highly size-controlled iron nanoparticles, it is in turn featured by a suppressed formation of iron nanoparticles to achieve an efficient iron coating solely onto the surfaces of rare-earth magnet powder. The Nd-Fe-B magnetic powder was successfully coated by iron shells whose thicknesses were of the order of submicrometer to micrometer, being tuneable by the amount of initially loaded iron pentacarbonyl in a reaction flask. The amount of the coated iron reached to more than 10 wt.% of the initial Nd-Fe-B magnetic powder, which is practically sufficient to fabricate Nd-Fe-B/α-Fe nanocomposite permanent magnets.

  15. Synthesis and densification of Cu-coated Ni-based amorphous composite powders

    International Nuclear Information System (INIS)

    Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

    2007-01-01

    Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

  16. Ultrasound-assisted powder-coating technique to improve content uniformity of low-dose solid dosage forms

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Antikainen, Osmo

    2010-01-01

    An ultrasound-assisted powder-coating technique was used to produce a homogeneous powder formulation of a low-dose active pharmaceutical ingredient (API). The powdered particles of microcrystalline cellulose (MCC; Avicel® PH-200) were coated with a 4% m/V aqueous solution of riboflavin sodium...

  17. Thin-coating as an alternative approach to improve flow properties of ibuprofen powder

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Ehlers, Henrik

    2010-01-01

    In the present study, thin-coating as a potential method for improving flow properties of cohesive ibuprofen powder was introduced. Briefly, the technique was based on the successive deposition of ultrasound-assisted fine polymer mist onto the surface of the powdered active pharmaceutical...... ingredient (API), producing individual particles with a hydrophilic thin-coat. A 0.15% m/V aqueous solution of hydroxypropyl methylcellulose (HPMC) was used. Particle size and surface analysis revealed a decrease in the cohesiveness of ibuprofen powder and an increase in the homogeneity of particle surfaces...

  18. 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. 

  19. Characterisation of WC-12Co thermal spray powders and HPHVOF wear resistant coatings

    CSIR Research Space (South Africa)

    Lovelock, HDL

    1998-01-01

    Full Text Available were selected for the deposition of thermal spray coatings using the JP 5000 high pressure high velocity oxyfuel (HPHVOF) system. Dry sand rubber wheel abrasion tests were performed on the coatings in order to determine the effect of powder...

  20. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    Science.gov (United States)

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

  1. Behaviour of CaO coating of gas atomized Mg powders using mechanical milling process

    International Nuclear Information System (INIS)

    Kim, Sun-Mi; Kim, Yong Hwan; Kim, Young Do; Kim, Taek-Soo

    2011-01-01

    Highlights: → This work is very new, since behaviour of CaO coating with milling time as desulfurizer is not frequently reported. → The manuscript reports the new manner of Mg powders desulfurizer development by the innovative process. - Abstract: In order to synthesize a thermally stable Mg powder as a desulfurizer of iron, pure Mg was gas atomized to powders and coated by CaO powders, to produce a thermally stable desulfurizer using a mechanical milling process. Since the effect of desulfurization is dependent on the degree of surface modification, coating behaviours such as the size, morphology and layer thickness were investigated as a function of milling condition. As the milling conducted from 10 min to 30 min, 1 h, 3 h, 6 h, 12 h, CaO particles began to stick on the surface of Mg powders. The layer of CaO formed from 1 h milling was about 17 μm thick and gradually thickened to be 28 μm, 32 μm and 37 μm with increasing the milling time to 3 h, 6 h and 12 h, respectively. The shape of coated powder became more spherical after 1 h milling, being mostly spherical after 6 h. Desulfurization rate and uniformity were evaluated for the various thickness of the coating layer.

  2. Coated powder for electrolyte matrix for carbonate fuel cell

    International Nuclear Information System (INIS)

    Iacovangelo, C.D.; Browall, K.W.

    1985-01-01

    A plurality of electrolyte carbonate-coated ceramic particle which does not differ significantly in size from that of the ceramic particle and wherein no significant portion of the ceramic particle is exposed is fabricated into a porous tape comprised of said coated-ceramic particles bonded together by the coating for use in a molten carbonate fuel cell

  3. Wear Resistant Thermal Sprayed Composite Coatings Based on Iron Self-Fluxing Alloy and Recycled Cermet Powders

    Directory of Open Access Journals (Sweden)

    Heikki SARJAS

    2012-03-01

    Full Text Available Thermal spray and WC-Co based coatings are widely used in areas subjected to abrasive wear. Commercial  cermet thermal spray powders for HVOF are relatively expensive. Therefore applying these powders in cost-sensitive areas like mining and agriculture are hindered. Nowadays, the use of cheap iron based self-fluxing alloy powders for thermal spray is limited. The aim of this research was to study properties of composite powders based on self-fluxing alloys and recycled cermets and to examine the properties of thermally sprayed (HVOF coatings from composite powders based on iron self-fluxing alloy and recycled cermet powders (Cr3C2-Ni and WC-Co. To estimate the properties of  recycled cermet powders, the sieving analysis, laser granulometry and morphology were conducted. For deposition of coatings High Velocity Oxy-Fuel spray was used. The structure and composition of powders and coatings were estimated by SEM and XRD methods. Abrasive wear performance of coatings was determined and compared with wear resistance of coatings from commercial powders. The wear resistance of thermal sprayed coatings from self-fluxing alloy and recycled cermet powders at abrasion is comparable with wear resistance of coatings from commercial expensive spray powders and may be an alternative in tribological applications in cost-sensitive areas.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1338

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

    OpenAIRE

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

    2014-01-01

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

  5. Material Evaluation and Process Optimization of CNT-Coated Polymer Powders for Selective Laser Sintering

    Directory of Open Access Journals (Sweden)

    Shangqin Yuan

    2016-10-01

    Full Text Available Multi-walled carbon nanotubes (CNTs as nano-reinforcements were introduced to facilitate the laser sintering process and enhance the thermal and mechanical properties of polymeric composites. A dual experimental-theoretical method was proposed to evaluate the processability and predict the process parameters of newly developed CNT-coated polyamide 12 (CNTs/PA12 powders. The thermal conductivity, melt viscosity, phase transition and temperature-dependent density and heat capacity of PA12 and CNTs/PA12 powders were characterized for material evaluation. The composite powders exhibited improved heat conduction and heat absorption compared with virgin polymer powders, and the stable sintering range of composite powders was extended and found to be favourable for the sintering process. The microstructures of sintered composites revealed that the CNTs remained at the powder boundaries and formed network architectures, which instantaneously induced the significant enhancements in tensile strength, elongation at break and toughness without sacrificing tensile modulus.

  6. Electrochemical investigation of powder coatings and their application to magnesium-rich primers for corrosion protection

    Science.gov (United States)

    Orgon, Casey Roy

    Corrosion is the decomposition of metal and metal alloys which threatens the integrity of man-made structures. One of the more efficient methods of delaying the corrosion process in metals is by coatings. In this work, the durability of two polyester powder coatings were investigated for corrosion protection of AA-2024-T3. Polyester powder coatings crosslinked by either triglycidyl isocyanurate (TGIC) or beta-hydroxyalkyl amide (HAA) compounds were prepared and investigated for barrier protection of metal substrates by electrochemical impedance spectroscopy (EIS). Polyester-TGIC coatings were found to provide better long-term protection, which can be attributed to the increased mechanical strength and higher concentration of crosslinking in the coating films. Additionally, the polyester powder coatings, along with a fusion bonded epoxy (FBE) were investigated for their compatibility as a topcoat for magnesium-rich primers (MgRP). Under proper application conditions, powder topcoats were successfully applied to cured MgRP while corrosion protection mechanisms of each system were maintained.

  7. Influence of additives on melt viscosity, surface tension, and film formation of dry powder coatings.

    Science.gov (United States)

    Sauer, Dorothea; McGinity, James W

    2009-06-01

    Limited information on thermally cured dry-powder coatings used for solid dosage forms has been available in the literature. The aim of this study was to characterize the film formation process of Eudragit L 100-55 dry-powder coatings and to investigate the influence of film additives on melt viscosity and surface tension. The coating process employed no liquids and the plasticizer was combined with the polymer using hot melt extrusion. Thermoanalytical methods including differential scanning calorimetry and thermogravimetric analysis (TGA) were used to investigate the thermal properties of the dry-coating formulations. The rheological behavior of the coating formulations were characterized with the extrusion torque, and the surface energy parameters were determined from contact angle measurements. The influence of the level of triethyl citrate (TEC) as plasticizer and polyethylene glycol (PEG) 3350 in the polymer film on film formation was investigated using a digital force tester. TGA confirmed thermal stability of all coating excipients at the investigated curing conditions. Increasing TEC levels and the addition of PEG 3350 as a low melting excipient in the coating reduced the viscosity of the polymer. Plasticization of the polymer with TEC increased the surface free energy, whereas the admixture of 10% PEG 3350 did not affect the surface free energy of Eudragit L 100-55. The spreading coefficient of the polymers over two sample tablet formulations was reduced with increasing surface free energy. During the curing process, puncture strength, and elongation of powder-cast films increased. The effect of curing time on the mechanical properties was dependent on the plasticizer content. The incorporation of TEC and PEG 3350 into the Eudragit L 100-55 powder coating formulation improved film formation. Mechanical testing of powder-cast films showed an increase of both elongation and puncture strength over the curing process as criterion for polymer particle fusion

  8. The Effectiveness of a NiCrY-Coating on a Powder Metallurgy Disk Superalloy

    Science.gov (United States)

    Gabb, Timothy P.; Miller, Robert A.; Nesbitt, James A.; Draper, Susan L.; Rogers, Richard B.; Telesman, Jack

    2018-01-01

    Protective ductile coatings could be necessary to mitigate oxidation and corrosion attack on superalloy disks in some turbine engine applications. However, the effects of coatings on fatigue life of the disk during service are an important concern. The objective of this study was to investigate how such a coating could perform after varied post-coating processing. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, preparation treated, exposed, and then subjected to fatigue at high temperature. The effects of varied shot peening, preparation treatment, and exposures on fatigue life with and without the coating were compared. Each of these variables and several of their interactions significantly influenced fatigue life.

  9. Electrodeposition fabrication of Co-based superhydrophobic powder coatings in non-aqueous electrolyte

    Science.gov (United States)

    Chen, Zhi; Hao, Limei; Duan, Mengmeng; Chen, Changle

    2013-05-01

    A rapid, facile, one-step process was developed to fabricate Co-based superhydrophobic powder coatings on the stainless steel surfaces with a nonaqueous electrolyte by the electrodeposition method. The structure and composition of the superhydrophobic surfaces were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and contact angle measurement. The results show that the special hierarchical structures along with the low surface energy lead to the high superhydrophobicity of the substrate surface. The shortest process of constructing the superhydrophobic surface is only 30 seconds, the high contact angle is greater than 160°, and the rolling angle is less than 2°. The method can be used to fabricate the superhydrophobic powder coatings at any conductive cathodic surface, and the as-prepared superhydrophobic powder coatings have advantages of transferability, repairability, and durability. It is expected that this facile method will accelerate the large-scale production of superhydrophobic material.

  10. Evaluation of a Low Temperature Cure Powder Coating

    Science.gov (United States)

    2008-05-01

    4”x6”x1/4” Al 2024-T3 panels were chromate conversion coated by NDCEE per MIL-DTL-5514F Type 1 Class A  Reserved for LTCPC  27 – 4”x6”x1/4” Al...2024-T3 panels were chromate conversion coated by FRC Southeast per MIL-DTL- 5514F Type 1 Class A  Reserved for baseline coating JSEM - May...conducted under contract W74V8H- 04-D-0005 Task 427. DISCLAIMER: The contents of this document are not to be used for advertising , publication, or

  11. Study of Velocity and Materials on Tribocharging of Polymer Powders for Powder Coating Applications

    Science.gov (United States)

    Biris, Alex S.; Trigwell, Steve; Sims, Robert A.; Mazumder, Malay K.

    2005-01-01

    Electrostatic powder deposition is widely used in a plethora of industrial-applications ranging from the pharmaceutical and food.industries, to farm equipment and automotive applications. The disadvantages of this technique are possible back corona (pin-like formations) onset and the Faraday penetration limitation (when the powder does not penetrate in some recessed areas). A possible solution to overcome these problems is to use tribochargers to electrostatically charge the powder. Tribocharging, or contact charging while two materials are in contact, is related to the work function difference between the contacting materials and generates bipolarly charged particles. The generation of an ion-free powder cloud by tribocharging with high bipolar charge and an overall charge density of almost zero, provides a better coverage of the recessed areas. In this study, acrylic and epoxy powders were fluidized and charged by passing through stainless steel, copper, aluminum, and polycarbonate static mixers, respectively. The particle velocity was varied to determine its effect on the net charge-to-mass ratio (QIM) acquired by the powders. In general, the Q/M increases rapidly when the velocity was increased from 1.5 to 2.5 m/s, remaining almost constant for higher velocities. Charge separation experiments showed bipolar charging for all chargers.

  12. Nano powders, components and coatings by plasma technique

    Science.gov (United States)

    McKechnie, Timothy N. (Inventor); Antony, Leo V. M. (Inventor); O'Dell, Scott (Inventor); Power, Chris (Inventor); Tabor, Terry (Inventor)

    2009-01-01

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  13. Nano powders, components and coatings by plasma technique

    Science.gov (United States)

    McKechnie, Timothy N [Brownsboro, AL; Antony, Leo V. M. [Huntsville, AL; O'Dell, Scott [Arab, AL; Power, Chris [Guntersville, AL; Tabor, Terry [Huntsville, AL

    2009-11-10

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  14. Residual Stresses in a NiCrY-Coated Powder Metallurgy Disk Superalloy

    Science.gov (United States)

    Gabb, Timothy P.; Rogers, Richard B.; Nesbitt, James A.; Puleo, Bernadette J.; Miller, Robert A.; Telesman, Ignacy; Draper, Susan L.; Locci, Ivan E.

    2017-01-01

    Protective ductile coatings will be necessary to mitigate oxidation and corrosion attack on superalloy disks exposed to increasing operating temperatures in some turbine engine environments. However, such coatings must be resistant to harmful surface cracking during service. The objective of this study was to investigate how residual stresses evolve in such coatings. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, and then subjected to fatigue in air at room and high temperatures. The effects of shot peening and fatigue cycling on average residual stresses and other aspects of the coating were assessed. Shot peening did induce beneficial compressive residual stresses in the coating and substrate. However, these stresses became more tensile in the coating with subsequent heating and contributed to cracking of the coating in long intervals of cycling at 760 C. Substantial compressive residual stresses remained in the substrate adjacent to the coating, sufficient to suppress fatigue cracking. The coating continued to protect the substrate from hot corrosion pitting, even after fatigue cracks initiated in the coating.

  15. Cobalt and cerium coated Ni powder as a new candidate cathode material for MCFC

    International Nuclear Information System (INIS)

    Kim, Min Hyuk; Hong, Ming Zi; Kim, Young-Suk; Park, Eunjoo; Lee, Hyunsuk; Ha, Hyung-Wook; Kim, Keon

    2006-01-01

    The dissolution of nickel oxide cathode in the electrolyte is one of the major technical obstacles to the commercialization of molten carbonate fuel cell (MCFC). To improve the MCFC cathode stability, the alternative cathode material for MCFC was prepared, which was made of Co/Ce-coated on the surface of Ni powder using a polymeric precursor based on the Pechini method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) were employed in characterization of the alternative cathode materials. The Co/Ce-coated Ni cathode prepared by the tape-casting technique. The solubility of the Co/Ce-coated Ni cathode was about 80% lower when compare to that of pure Ni cathode under CO 2 :O 2 (66.7:33.3%) atmosphere at 650 deg. C. Consequently, the fine Co/Ce-coated Ni powder could be confirmed as a new alternative cathode material for MCFC

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  17. Ultraviolet Curable Powder Coatings with Robotic Curing for Aerospace Applications

    Science.gov (United States)

    2012-05-01

    millions of dollars annually on solvent- based coatings  Hexavalent chrome primer use still very widespread  Contains or requires volatile solvent...functionality can be added  Various advanced non- chrome corrosion inhibitors DISTRIBUTION A. Approved for public release; distribution unlimited. Case

  18. The pigmentation of powder coatings with the use of block copolymer dispersants

    NARCIS (Netherlands)

    Duivenvoorde, F.L.; Nostrum, van C.F.; Linde, van der R.

    1999-01-01

    The dispersing of pigments in powder coatings is a difficult and complicated process. The incomplete dispersion under standard extrusion conditions can be attributed to a combination of poor pigment wetting and insufficient disruption of the pigment agglomerates, as a result of the rheological

  19. INFLUENCE OF REPAINTING ON THE MECHANICAL PROPERTIES, SURFACE TOPOGRAPHY AND MICROSTRUCTURE OF POLYESTER POWDER COATINGS

    Directory of Open Access Journals (Sweden)

    Mirosław Szala

    2017-06-01

    This study examined three different electrostatic spray epoxy coatings with matt, silk gloss and fine structure-matt finish. Test panels were prepared as single- and double-layer paint coatings on the aluminum alloy 6060 substrate. Hence, six test sets of coatings were deposited. Each set contained six samples. The microstructure of the cross section of coating was investigated by scanning electron microscopy (SEM and light optical microscopy (metallographic and stereoscopy microscope. The chemical composition of coating was analyzed by the SEM-EDS method. The 2D surface roughness of single- and double-layer coatings and 3D surface topography maps were examined using a profile measurement gauge. The mechanical properties of coatings were measured by cupping, bending, impact, adhesion to substrate tests run according to standard procedures. As a result, the influence of repainting of polyester powder coatings on their properties was determined. The results demonstrate that repainting has no effect on the microstructure and coating adhesion to substrate as well as the bending test results and roughness of matt and silk gloss coatings. It has been found that repainting affects the results of impact and cupping tests as well as the roughness of samples with fine structure surface finish.

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

    Directory of Open Access Journals (Sweden)

    Paula Tibola Bertuoli

    2014-06-01

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

  1. Electrochemical and anticorrosion performances of zinc-rich and polyaniline powder coatings

    International Nuclear Information System (INIS)

    Meroufel, A.; Deslouis, C.; Touzain, S.

    2008-01-01

    In this work, hydrochloride polyaniline (PANI-Cl) powder was incorporated as a conductive pigment into powder zinc-rich primer (ZRP) formulations in order to enhance the electronic conduction paths between zinc particles inside the coating and the steel substrate (i.e. percolation). Coatings were applied onto steel substrates and immersed in a 3% NaCl solution at ambient temperature. The protective properties and electrochemical behaviour of coatings were investigated by monitoring the free corrosion potential versus time and by using EIS. It was found that corrosion potential remains cathodic and constant for a long time up to 100 days of immersion. From EIS results, it was shown that the coatings exhibit larger impedance values than those observed with liquid or other zinc-rich powder formulations containing carbon black. From Raman spectroscopy results, it may be proposed that zinc particles in contact with PANI-Cl pigments were passivated. Other zinc particles remain still active which ensures the cathodic protection of the substrate. Moreover, coatings exhibit good barrier properties

  2. Stainless steel coatings produced through atmospheric plasma spraying study of in flight powder behavior and coating structure

    International Nuclear Information System (INIS)

    Denoirjean, A.; Denoirjean, P.; Fauchais, P.; Labbe, J.C.; Khan, A.A.

    2005-01-01

    The Stainless Steel coatings deposited through Atmospheric Plasma Spraying over mild steel surface present an interest from commercial point of view, especially for the applications where corrosion resistance or inertness towards severe environment is required. Atmospheric Plasma Spraying is fast and relatively less expensive choice as compared to Vacuum Plasma Spraying, the only limitation being the extremely reactive nature of metallic powders used. A study of the behaviour of metallic powders within an Atmospheric Plasma Jet is presented in view of better understanding and eventual improvement in coating properties. Metallic powder particles show very interesting features when individual particles are collected after passing them through a DC Blown Arc Thermal Plasma Jet under Atmospheric Pressure. The spraying was carried out under air which makes the significance of these results even more interesting from the industrial point of view. Proper control of Spraying Parameters can help produce Stainless Steel coatings of reasonably low porosity and a typical lamellar microstructure. The results of SEM, AFM and XRD are discussed. A strange oxidation phenomenon under highly non equilibrium conditions is observed. (author)

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

    International Nuclear Information System (INIS)

    Qing Yuchang; Zhou Wancheng; Luo Fa; Zhu Dongmei

    2010-01-01

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

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

    Science.gov (United States)

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

    2010-02-01

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

  5. Titania-polymeric powder coatings with nano-topography support enhanced human mesenchymal cell responses.

    Science.gov (United States)

    Mozumder, Mohammad Sayem; Zhu, Jesse; Perinpanayagam, Hiran

    2012-10-01

    Titanium implant osseointegration is dependent on the cellular response to surface modifications and coatings. Titania-enriched nanocomposite polymeric resin coatings were prepared through the application of advanced ultrafine powder coating technology. Their surfaces were readily modified to create nano-rough (topographies that supported human embryonic palatal mesenchymal cell responses. Energy dispersive x-ray spectroscopy confirmed continuous and homogenous coatings with a similar composition and even distribution of titanium. Scanning electron microscopy (SEM) showed complex micro-topographies, and atomic force microscopy revealed intricate nanofeatures and surface roughness. Cell counts, mitochondrial enzyme activity reduction of yellow 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to dark purple, SEM, and inverted fluorescence microscopy showed a marked increase in cell attachment, spreading, proliferation, and metabolic activity on the nanostructured surfaces. Reverse Transcription- Polymerase Chain Reaction (RT-PCR) analysis showed that type I collagen and Runx2 expression were induced, and Alizarin red staining showed that mineral deposits were abundant in the cell cultures grown on nanosurfaces. This enhancement in human mesenchymal cell attachment, growth, and osteogenesis were attributed to the nanosized surface topographies, roughness, and moderate wetting characteristics of the coatings. Their dimensional similarity to naturally occurring matrix proteins and crystals, coupled with their increased surface area for protein adsorption, may have facilitated the response. Therefore, this application of ultrafine powder coating technology affords highly biocompatible surfaces that can be readily modified to accentuate the cellular response. Copyright © 2012 Wiley Periodicals, Inc.

  6. Synthesis, characterization and electrochemical performance of core/shell structured carbon coated silicon powders for lithium ion battery negative electrodes

    Directory of Open Access Journals (Sweden)

    Tuğrul Çetinkaya

    2017-06-01

    Full Text Available Surface of nano silicon powders were coated with amorphous carbon by pyrolysis of polyacronitrile (PAN polymer. Microstructural characterization of amorphous carbon coated silicon powders (Si-C were carried out using scanning electron microscopy (SEM and thickness of carbon coating is defined by transmission electron microscopy (TEM. Elemental analyses of Si-C powders were performed using energy dispersive X-ray spectroscopy (EDS. Structural and phase characterization of Si-C composite powders were investigated using X-ray diffractometer (XRD and Raman spectroscopy. Produced Si-C powders were prepared as an electrode on the copper current collector and electrochemical tests were carried out using CR2016 button cells at 200 mA/g constant current density. According to electrochemical test results, carbon coating process enhanced the electrochemical performance by reducing the problems stem from volume change and showed 770 mAh/g discharge capacity after 30 cycles.

  7. Effects of Rare Earth Elements on Properties of Ni-Base Superalloy Powders and Coatings

    Directory of Open Access Journals (Sweden)

    Chunlian Hu

    2017-02-01

    Full Text Available NiCrMoY alloy powders were prepared using inert gas atomization by incorporation of rare earth elements, such as Mo, Nb, and Y into Ni60A powders, the coatings were sprayed by oxy-acetylene flame spray and then remelted with high-frequency induction. The morphologies, hollow particle ratio, particle-size distribution, apparent density, flowability, and the oxygen content of the NiCrMoY alloy powders were investigated, and the microstructure and hardness of the coatings were evaluated by optical microscopy (OM. Due to incorporation of the rare earth elements of Mo, Nb, or Y, the majority of the NiCrMoY alloy particles are near-spherical, the minority of which have small satellites, the surface of the particles is smoother and hollow particles are fewer, the particles exhibit larger apparent density and lower flowability than those of particles without incorporation, i.e., Ni60A powders, and particle-size distribution exhibits a single peak and fits normal distribution. The microstructure of the NiCrMoY alloy coatings exhibits finer structure and Rockwell hardness HRC of 60–63 in which the bulk- and needle-like hard phases are formed.

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

    Science.gov (United States)

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

    1993-01-01

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

  9. Magnetic and microstructural properties of Fe{sub 3}O{sub 4}-coated Fe powder soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Jo Sunday, Katie [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States); Hanejko, Francis G. [Hoeganaes Corporation, Cinnaminson, NJ08077 (United States); Taheri, Mitra L., E-mail: mtaheri@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States)

    2017-02-01

    Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and possess high melting temperatures, thus providing adequate electrical barriers between metallic particles. In this work, iron powder was coated with Fe{sub 3}O{sub 4} particles via mechanical milling, then compacted and cured in an inert gas environment. We find density and coercivity to improve with increasing temperatures; however, core loss greatly increases, which is attributed to the formation of a more conductive iron-oxide phase and less resistive Fe volume. Our work begins to exemplify the unique qualities and potential for ferrite-based coatings using traditional powder metallurgy techniques and higher curing temperatures for electromagnetic devices. - Highlights: • Fe{sub 3}O{sub 4}-coated Fe powder was produced via mechanical milling, then compacted and cured into composite form. • SEM/EDS confirm Fe particles are individually isolated with iron-oxide coating material. • Larger particle sizes show improved core loss and coercivity measurements. • We report good magnetic properties for compaction at 800 MPa and a curing temperature of 700 °C.

  10. Characterization of boride-based powders and detonation gun sprayed cermet coatings

    International Nuclear Information System (INIS)

    Keraenen, J.; Stenberg, T.; Maentylae, T.

    1995-01-01

    Detonation gun sprayed (DGS) cermet coatings containing complex ternary transition metal boride as hard particles dispersed in a stainless steel or nickel based superalloy matrix have been characterized. Microstructure of the coatings, as well as powders, were studied with optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and analytical transmission electron microscopy (AEM). X-ray microanalysis of the coatings were carried out using energy dispersive X-ray spectrometer (EDS) attached to the SEM and AEM. Moreover, abrasion wear resistance of the coatings was evaluated with a rubber wheel abrasion test equipment. The general microstructure of studied coatings appeared to be heterogeneous in the terms of the distribution, size and crystallographic nature of the phases. Nonetheless, very low porosities were obtained and in the coatings the oxide phase as well as the unmelted particles and the formation of oxide phase were avoided by optimization of DGS parameters. So far the abrasive wear resistance of boride-based cermet coatings is not so good as that of the WC-12Co coatings

  11. Tungsten oxide coatings deposited by plasma spray using powder and solution precursor for detection of nitrogen dioxide gas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao, E-mail: zhangc@yzu.edu.cn [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); Wang, Jie [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); Geng, Xin [College of Mechanical Engineering, Yangzhou University, Yangzhou 225127 (China); College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China)

    2016-05-25

    Increasing attention has been paid on preparation methods for resistive-type gas sensors based on semiconductor metal oxides. In this work, tungsten oxide (WO{sub 3}) coatings were prepared on alumina substrates and used as gas sensitive layers. The coatings were deposited by atmospheric plasma spray using powder, solution precursor, or a combination of both. Tungsten oxide powder through a powder port and ammonium tungstate aqueous solution through a liquid port were injected into plasma stream respectively or together to deposit WO{sub 3} coatings. Phase structures in the coatings were characterized by X-ray diffraction analyzer. The field-emission scanning electron microscopy images confirmed that the coatings were in microstructure, nanostructure or micro-nanostructure. The sensing properties of the sensors based on the coatings exposed to 1 ppm nitrogen dioxide gas were characterized in a home-made instrument. Sensing properties of the coatings were compared and discussed. The influences of gas humidity and working temperature on the sensor responses were further studied. - Highlights: • Porous gas sensitive coatings were deposited by plasma spray using powder and solution precursor. • Crystallized WO{sub 3} were obtained through hybrid plasma spray plus a pre-conditioned step. • Plasma power had an important influence on coating microstructure. • The particle size of atmospheric plasma-sprayed microstructured coating was stable. • Solution precursor plasma-sprayed WO{sub 3} coatings had nanostructure and showed good responses to 1 ppm NO{sub 2}.

  12. 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)

  13. ELASTO-PLASTIC DEFORMATION OF COMPOSITE POWDERS WITH LAYERED CARBON AND CARBIDE-FORMING ELEMENT COATING

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2012-01-01

    Full Text Available Coating structure formation under magnetron spraying of titanium and carbon cathodes and combined cathodes, namely cobalt (EP 131 – nickel, tungsten – carbon have been investigated under conditions of carbide separate synthesis within the temperature range of 650–1200 °C. Usage of cobalt and nickel particles as matrix material leads to their rapid thermal expansion under heating during sintering process in the dilatometer. Subsequent plastic deformation of sintered samples provides obtaining a composite powder material that is a composite with framing structure of cobalt, titanium and tungsten carbides in the coatings.

  14. Properties of polyester based powder coating containing Cloisite®30B modified with silane 3-aminopropyltriethoxysilane

    International Nuclear Information System (INIS)

    Bertuoli, P.T.; Frizzo, V.P.; Zattera, A.J.; Scienza, L.C.

    2014-01-01

    The incorporation of clay into a polymer matrix results in nanocomposites with mechanical strength, thermal and barrier properties superior to the free filler matrix. With the aim to obtain a powder coating with better thermal properties than the coating free of filler, the organoclay Cloisite®30B was modified with 3-aminopropyltriethoxysilane (APS) and incorporated to a polyester based powder coating, on proportions of 2 to 8 wt% in the melt state. The powder coatings were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The powder coating containing clay showed no alteration in the basal spacing compared to that basal spacing of the clay. Compared to the powder coating free of the clay, powder coatings containing clay had lower thermal stability due to the presence of the organic modifier. The presence of clay reduced the crosslinking temperature and the incorporation of 2 wt% of the clay caused the increase in the energy released in the crosslinking process. (author)

  15. Assesment of (Mn,Co)3O4 powders for possible coating material for SOFC/SOEC interconnects

    DEFF Research Database (Denmark)

    Szymczewska, D.; Molin, Sebastian; Venkatachalam, Vinothini

    2015-01-01

    In this work (Mn,Co)3O4 spinel powders with different Mn:Co ratio (1:1 and 1:2) and from different commercial suppliers are evaluated for possible powder for production of interconnect coatings. Sinterability of the powders is evaluated on pressed pellets sintered in oxidizing and in reducing/oxidizing...... that with appropriate powder it is possible to produce adherent protective coating with a well-controlled thickness....... atmospheres. For selected powder, coatings are then prepared by the electrophoretic deposition method on Crofer 22 APU stainless steel coupons. Effects of dispersant/iodine content and deposition voltage and times are evaluated. Thickness as a function of deposition parameters is described. Results show...

  16. Assesment of (Mn,Co)33O4 powders for possible coating material for SOFC/SOEC interconnects

    International Nuclear Information System (INIS)

    Szymczewska, D.; Jasinski, P.; Molin, S.; Venkatachalam, V.; Chen, M.; Hendriksen, P.V.

    2016-01-01

    In this work (Mn,Co) 3 O 4 spinel powders with different Mn:Co ratio (1:1 and 1:2) and from different commercial suppliers are evaluated for possible powder for production of interconnect coatings. Sinterability of the powders is evaluated on pressed pellets sintered in oxidizing and in reducing/oxidizing atmospheres. For selected powder, coatings are then prepared by the electrophoretic deposition method on Crofer 22 APU stainless steel coupons. Effects of dispersant/iodine content and deposition voltage and times are evaluated. Thickness as a function of deposition parameters is described. Results show that with appropriate powder it is possible to produce adherent protective coating with a well-controlled thickness

  17. The effect of YBa2Cu3O7-x powder characteristics on thick coatings prepared by atmospheric plasma spraying

    International Nuclear Information System (INIS)

    Georgiopoulos, E.; Tsetsekou, A.

    2000-01-01

    The development of superconducting YBa 2 Cu 3 O 7-x plasma sprayed coatings on metal substrates can be very useful for applications such as targets for thin-film deposition techniques (sputtering, laser ablation, ion assisted deposition) or magnetic shielding, due to the brittle nature of bulk superconductors. The plasma spraying technique is very flexible and can be used for manufacturing components with a large variety of geometries. This technique requires the use of powders with good rheological characteristics. In this study, YBa 2 Cu 3 O 7-x powders were produced by using the conventional solid-state reaction route and also by spray drying a solution of nitrate precursors. Both powders, as well as mixtures of them, were plasma sprayed to develop coatings on stainless-steel substrates, with the aim of studying the effect of the feedstock powder characteristics on the coating properties. It was found that by optimizing the plasma spraying conditions, good quality coatings could be obtained. However, the powder morphology and homogeneity significantly affect the coating quality. More homogeneous powders lead to better results, the spray-dried powder being the best because of its enhanced rheological properties and good morphology. (author)

  18. EXPLOSIVE COMPACTION OF CLAD GRAPHITE POWDERS AND OBTAINING OF COATINGS ON THEIR BASE

    Energy Technology Data Exchange (ETDEWEB)

    A. B. PEIKRISHIVILI; ET AL

    2000-11-01

    In order to consolidate graphite based powders and in order to obtain coatings with density values near to the theoretical ones clad graphite powders of the C{sub graphite} - Ni (C{sub g} - Ni) compositions were explosively compacted under different loading conditions. Theoretical calculations revealed that for assessing the stress-deformed state of C{sub g} - Ni compositions and computing the normal and tangent stress components (when V{sub D} < C{sub longitudinal} and V{sub D} < C{sub transversal}) it is recommended to apply the dynamic problem's solution model while the pressure impulse P = f(x) is being uniformly spread with constant rate along the boundary of a semi-infinite elastic body. The results of our experiments showed that it is possible to obtain high dense coatings from C{sub g}-Ni compositions bonded by an intermediate layer to the substrate material. The structure and properties of the coatings depends on the intensity of the shock loading and temperature. The effect of the shock loading conditions (temperature, loading intensity) on the structure, properties and structure/properties relationships for the C{sub g} - Ni coatings are discussed.

  19. Fabrication of dendritic silver-coated copper powders by galvanic displacement reaction and their thermal stability against oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yu-Seon [School of Chemical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Farad Materials Co., Ltd., Suwon 16419 (Korea, Republic of); An, Chang Yong; Kannan, Padmanathan Karthick; Seo, Nary [School of Chemical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Zhuo, Kai [School of Chemical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Farad Materials Co., Ltd., Suwon 16419 (Korea, Republic of); Yoo, Tae Kyong [School of Chemical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Chung, Chan-Hwa, E-mail: chchung@skku.edu [School of Chemical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Farad Materials Co., Ltd., Suwon 16419 (Korea, Republic of)

    2016-12-15

    Highlights: • The dendritic silver-coated copper powders with high specific surface area have been prepared using a simple wet chemical reduction process at room temperature. • It is found that the Cu starts to be oxidized into Cu{sub 2}O followed by CuO at elevated temperatures. • The more amount of Ag-coating provides the less oxidation, which confirms that the Ag-shell prevents the Cu-core from oxidation. • The resistivity of dendritic 33.27 wt.% Ag-coated Cu powders was measured to 25.67 μΩ cm after the annealing at 150 °C for 30 min. - Abstract: Two steps of wet chemical processes have been developed for the preparation of core-shell nanostructures of copper and silver, which is a facile and low cost method for the production of large quantity of dendritic powders. First step involves a galvanic displacement reaction with hydrogen evolution which is the motive force of spontaneous electrochemical reaction. To achieve the core-shell structure, silver has been coated on the dendritic copper using the galvanic displacement reaction. The dendritic silver-coated copper powders exhibit high surface-area, excellent conductivity, and good oxidation resistance. It has been found that silver-coated copper powders maintain the electrical conductivity even after annealing at 150 °C for several to tens of minutes, thus it is a promising material and an alternative to pure silver powders in printed electronics application.

  20. Fabrication of dendritic silver-coated copper powders by galvanic displacement reaction and their thermal stability against oxidation

    International Nuclear Information System (INIS)

    Park, Yu-Seon; An, Chang Yong; Kannan, Padmanathan Karthick; Seo, Nary; Zhuo, Kai; Yoo, Tae Kyong; Chung, Chan-Hwa

    2016-01-01

    Highlights: • The dendritic silver-coated copper powders with high specific surface area have been prepared using a simple wet chemical reduction process at room temperature. • It is found that the Cu starts to be oxidized into Cu_2O followed by CuO at elevated temperatures. • The more amount of Ag-coating provides the less oxidation, which confirms that the Ag-shell prevents the Cu-core from oxidation. • The resistivity of dendritic 33.27 wt.% Ag-coated Cu powders was measured to 25.67 μΩ cm after the annealing at 150 °C for 30 min. - Abstract: Two steps of wet chemical processes have been developed for the preparation of core-shell nanostructures of copper and silver, which is a facile and low cost method for the production of large quantity of dendritic powders. First step involves a galvanic displacement reaction with hydrogen evolution which is the motive force of spontaneous electrochemical reaction. To achieve the core-shell structure, silver has been coated on the dendritic copper using the galvanic displacement reaction. The dendritic silver-coated copper powders exhibit high surface-area, excellent conductivity, and good oxidation resistance. It has been found that silver-coated copper powders maintain the electrical conductivity even after annealing at 150 °C for several to tens of minutes, thus it is a promising material and an alternative to pure silver powders in printed electronics application.

  1. Anti-carburizing Coating for Resin Sand Casting of Low Carbon Steel Based on Composite Silicate Powder Containing Zirconium

    Directory of Open Access Journals (Sweden)

    Zhan Chunyi

    2018-01-01

    Full Text Available This paper studied the structure and properties of anticarburizing coating based on composite silicate powder containing zirconium by X-ray diffraction analyzer, thermal expansion tester, digital microscope and other equipment. It is introduced that the application example of the coating in the resin-sand casting of ZG1Cr18Ni9Ti stainless steel impeller. The anti-carburizing effect of the coating on the surface layer of the cast is studied by using direct reading spectrometer and spectrum analyzer. The change of the micro-structure of the coating after casting and cooling is observed by scanning electron microscope. The analysis of anti-carburizing mechanism of the coating is presented. The results indicate that the coating possesses excellent suspension property, brush ability, permeability, levelling property and crackresistance. The coating exhibits high strength and low gas evolution. Most of the coating could be automatically stripped off flakily when the casting was shaken out. The casting possesses excellent surface finish and antimetal penetration effect. The carburizing layer thickness of the stainless steel impeller casting with respect to allowable upper limit of carbon content is about 1mm and maximum carburizing rate is 23.6%. The anticarburizing effect of casting surface is greatly improved than that of zircon powder coating whose maximum carburizing rate is 67.9% and the carburizing layer thickness with respect to allowable upper limit of carbon content is greater than 2mm. The composite silicate powder containing zirconium coating substantially reduces the zircon powder which is expensive and radioactive and mainly dependent on imports. The coating can be used instead of pure zircon powder coating to effectively prevent metal-penetration and carburizing of resin-sand-casting surface of low carbon steel, significantly improve the foundry production environment and reduce the production costs.

  2. A Novel Approach for Dry Powder Coating of Pellets with Ethylcellulose. Part II: Evaluation of Caffeine Release.

    Science.gov (United States)

    Albertini, Beatrice; Melegari, Cecilia; Bertoni, Serena; Dolci, Luisa Stella; Passerini, Nadia

    2018-04-01

    The objective of this study was to assess the efficacy and the capability of a novel ethylcellulose-based dry-coating system to obtain prolonged and stable release profiles of caffeine-loaded pellets. Lauric and oleic acids at a suitable proportion were used to plasticize ethylcellulose. The effect of coating level, percentage of drug loading, inert core particle size, and composition of the coating formulation including the anti-sticking agent on the drug release profile were fully investigated. A coating level of 15% w/w was the maximum layered amount which could modify the drug release. The best controlled drug release was obtained by atomizing talc (2.5% w/w) together with the solid plasticizer during the dry powder-coating process. SEM pictures revealed a substantial drug re-crystallization on the pellet surface, and the release studies evidenced that caffeine diffused through the plasticized polymer acting as pore former. Therefore, the phenomenon of caffeine migration across the coating layer had a strong influence on the permeability of the coating membrane. Comparing dry powder-coated pellets to aqueous film-coated ones, drug migration happened during storage, though more sustained release profiles were obtained. The developed dry powder-coating process enabled the production of stable caffeine sustained release pellets. Surprisingly, the release properties of the dry-coated pellets were mainly influenced by the way of addition of talc into the dry powder-coating blend and by the drug nature and affinity to the coating components. It would be interesting to study the efficacy of novel coating system using a different API.

  3. Obtention of polyester-montmorillonite (MMT) nanocomposites applied to powder coating - part 1: nanocomposites characterization

    International Nuclear Information System (INIS)

    Piazza, Diego; Zattera, Ademir J.; Silveira, Debora S.; Lorandi, Natalia P.; Birriel, Eliena J.; Scienza, Lisete C.

    2009-01-01

    The development and obtention of polymeric nanocomposites in the nanotechnology and nanoscience field have attracted great attention due to diversity of potential applications and significant property improvement when compared to conventional composites. In this work, commercial formulations of polyester-based powder coating with 0, 2 and 4% (w/w) of montmorillonite (MMT) were obtained by incorporation in the melting state and characterized by TEM, SEM, DSC, TGA and XRD. The nanocoatings were applied on the mild carbon steel panels by electrostatic paint. The microscopy analysis showed MMT in the coating film, predominantly in the exfoliated form, corroborated by XRD results. Some tactoid structures and a surface film with some defects and porous were also revealed. Progressive reduction of crosslinking temperature and thermal stability was observed in thermal analysis. The best clay dispersion in the coating and a higher quality film were achieved at 2% MMT concentration. (author)

  4. Analysis and experimental investigation of ceramic powder coating on aluminium piston

    Science.gov (United States)

    Pal, S.; Deore, A.; Choudhary, A.; Madhwani, V.; Vijapuri, D.

    2017-11-01

    Energy conservation and efficiency have always been the quest of engineers concerned with internal combustion engines. The diesel engine generally offers better fuel economy than its counterpart petrol engine. Even the diesel engine rejects about two thirds of the heat energy of the fuel, one-third to the coolant, and one third to the exhaust, leaving only about one-third as useful power output. Theoretically if the heat rejected could be reduced, then the thermal efficiency would be improved, at least up to the limit set by the second law of thermodynamics. Low Heat Rejection engines aim to do this by reducing the heat lost to the coolant. Thermal Barrier Coatings (TBCs) in diesel engines lead to advantages including higher power density, fuel efficiency, and multifuel capacity due to higher combustion chamber temperature. Using TBC can increase engine power by 8%, decrease the specific fuel consumption by 15-20% and increase the exhaust gas temperature by 200K. Although several systems have been used as TBC for different purposes, yttria stabilized zirconia with 7-8 wt.% yttria has received the most attention. Several factors playing important role in TBC life include thermal conductivity, thermo chemical stability at the service temperature, high thermo mechanical stability to the maximum service temperature and thermal expansion coefficient (TEC). This work mainly concentrates on the behaviour of three TBC powders under the same diesel engine conditions. This work finds out the best powder among yttria, alumina and zirconia to be used as a piston coating material i.e., the one resulting in lowest heat flux and low side skirt and bottom temperature has been chosen for the coating purpose. This work then analyses the coated sample for its surface properties such as hardness, roughness, corrosion resistance and microstructural study. This work aims at making it easier for the manufacturers choose the coating material for engine coating purposes and surface

  5. Mullite and Mullite/ZrO2-7wt.%Y2O3 Powders for Thermal Spraying of Environmental Barrier Coatings

    Science.gov (United States)

    Garcia, E.; Mesquita-Guimarães, J.; Miranzo, P.; Osendi, M. I.; Wang, Y.; Lima, R. S.; Moreau, C.

    2010-01-01

    Mullite and mullite/ZrO2-7wt.%Y2O3 coatings could be thought among the main protective layers for environment barrier coatings (EBCs) to protect Si-based substrates in future gas turbine engines. Considering that feedstock of the compound powder is not commercially available, two powder processing routes Spray Drying (SD) and Flame Spheroidization (FS) were implemented for both types of powders. For each method the particle size, the morphology, and microstructure of the powder particles was determined. In addition, the effect of the heat treatment on the powder crystallinity and microstructure of FS powders was also investigated. To evaluate their suitability as feedstock materials, the powders were plasma sprayed and their in-flight particle characteristics monitored for coatings production. The powder morphology was correlated to the in-flight particle characteristics and splat morphology to gain insight about into the influence of powder characteristics on the coating formation.

  6. Synthesis of mullite-based coatings from alumina and zircon powder mixtures by plasma spraying and laser remelting

    International Nuclear Information System (INIS)

    Hazra, S.; Das, J.; Bandyopadhyay, P.P.

    2015-01-01

    A mechanical mixture of alumina and pulverized zircon sand in 3:2 M ratio has been plasma sprayed to obtain mullite coating. Thereafter, the top layer of the coating has been remelted using laser. The presence of a mullite phase in the as-sprayed and laser remelted coatings has been confirmed qualitatively using X-ray diffraction. Both as-sprayed and laser remelted coatings have been characterized for their microstructure, hardness and porosity. The ultrafine grain structure of the coating produced by rapid quenching has been analyzed using transmission electron microscope. Presence of a mullite phase in the coatings has also been confirmed using small angle electron diffraction. Laser remelting has resulted in an appreciable reduction in porosity and increase in hardness in the coatings. - Highlights: • Mullite has been produced by plasma spraying of alumina–zircon powder mixture. • As sprayed coating shows good integrity. • Laser remelting reduced porosity and increased coating hardness

  7. Synthesis of mullite-based coatings from alumina and zircon powder mixtures by plasma spraying and laser remelting

    Energy Technology Data Exchange (ETDEWEB)

    Hazra, S. [Integrated Test Range, Chandipur, Balasore, Odisha 756025 (India); Das, J. [Department of Metallurgical and Materials Engineering, IIT Kharagpur, 721302 (India); Bandyopadhyay, P.P., E-mail: ppb@mech.iitkgp.ernet.in [Department of Mechanical Engineering, IIT Kharagpur, 721302 (India)

    2015-03-15

    A mechanical mixture of alumina and pulverized zircon sand in 3:2 M ratio has been plasma sprayed to obtain mullite coating. Thereafter, the top layer of the coating has been remelted using laser. The presence of a mullite phase in the as-sprayed and laser remelted coatings has been confirmed qualitatively using X-ray diffraction. Both as-sprayed and laser remelted coatings have been characterized for their microstructure, hardness and porosity. The ultrafine grain structure of the coating produced by rapid quenching has been analyzed using transmission electron microscope. Presence of a mullite phase in the coatings has also been confirmed using small angle electron diffraction. Laser remelting has resulted in an appreciable reduction in porosity and increase in hardness in the coatings. - Highlights: • Mullite has been produced by plasma spraying of alumina–zircon powder mixture. • As sprayed coating shows good integrity. • Laser remelting reduced porosity and increased coating hardness.

  8. Optimization of a Wcl6 CVD System to Coat UO2 Powder with Tungsten

    Science.gov (United States)

    Belancik, Grace A.; Barnes, Marvin W.; Mireles, Omar; Hickman, Robert

    2015-01-01

    In order to achieve deep space exploration via Nuclear Thermal Propulsion (NTP), Marshall Space Flight Center (MSFC) is developing W-UO2 CERMET fuel elements, with focus on fabrication, testing, and process optimization. A risk of fuel loss is present due to the CTE mismatch between tungsten and UO2 in the W-60vol%UO2 fuel element, leading to high thermal stresses. This fuel loss can be reduced by coating the spherical UO2 particles with tungsten via H2/WCl6 reduction in a fluidized bed CVD system. Since the latest incarnation of the inverted reactor was completed, various minor modifications to the system design were completed, including an inverted frit sublimer. In order to optimize the parameters to achieve the desired tungsten coating thickness, a number of trials using surrogate HfO2 powder were performed. The furnace temperature was varied between 930 C and 1000degC, and the sublimer temperature was varied between 140 C and 200 C. Each trial lasted 73-82 minutes, with one lasting 205 minutes. A total of 13 trials were performed over the course of three months, two of which were re-coatings of previous trials. The powder samples were weighed before and after coating to roughly determine mass gain, and Scanning Electron Microscope (SEM) data was also obtained. Initial mass results indicated that the rate of layer deposition was lower than desired in all of the trials. SEM confirmed that while a uniform coating was obtained, the average coating thickness was 9.1% of the goal. The two re-coating trials did increase the thickness of the tungsten layer, but only to an average 14.3% of the goal. Therefore, the number of CVD runs required to fully coat one batch of material with the current configuration is not feasible for high production rates. Therefore, the system will be modified to operate with a negative pressure environment. This will allow for better gas mixing and more efficient heating of the substrate material, yielding greater tungsten coating per trial.

  9. A comparative physico-chemical study of chlorapatite and hydroxyapatite: from powders to plasma sprayed thin coatings.

    Science.gov (United States)

    Demnati, I; Grossin, D; Combes, C; Parco, M; Braceras, I; Rey, C

    2012-10-01

    Due to their bioactivity and osteoconductivity, hydroxyapatite (HA) plasma sprayed coatings have been widely developed for orthopedic uses. However, the thermodynamic instability of HA leads frequently to a mixture of phases which limit the functional durability of the coating. This study investigates the plasma spraying of chlorapatite (ClA) powder, known to melt without decomposition, onto pure titanium substrates using a low energy plasma spray system (LEPS). Pure ClA powder was prepared by a solid gas reaction at 950 °C and thermogravimetric analysis showed the good thermal stability of ClA powder in the range 30-1400 °C compared to that of the HA powder. Characterization of ClA coating showed that ClA had a very high crystalline ratio and no other crystalline phase was detected in the coating. HA and ClA coatings composition, microstructure and in vitro bioactivity potential were studied, compared and discussed. In vitro SBF test on HA and ClA coatings revealed the formation of a poorly crystalline apatite on the coating surface suggesting that we could expect a good osteoconductivity especially for the ClA coating prepared by the LEPS system.

  10. Optimizing Compliance and Thermal Conductivity of Plasma Sprayed Thermal Barrier Coatings via Controlled Powders and Processing Strategies

    Science.gov (United States)

    Tan, Yang; Srinivasan, Vasudevan; Nakamura, Toshio; Sampath, Sanjay; Bertrand, Pierre; Bertrand, Ghislaine

    2012-09-01

    The properties and performance of plasma-sprayed thermal barrier coatings (TBCs) are strongly dependent on the microstructural defects, which are affected by starting powder morphology and processing conditions. Of particular interest is the use of hollow powders which not only allow for efficient melting of zirconia ceramics but also produce lower conductivity and more compliant coatings. Typical industrial hollow spray powders have an assortment of densities resulting in masking potential advantages of the hollow morphology. In this study, we have conducted process mapping strategies using a novel uniform shell thickness hollow powder to control the defect microstructure and properties. Correlations among coating properties, microstructure, and processing reveal feasibility to produce highly compliant and low conductivity TBC through a combination of optimized feedstock and processing conditions. The results are presented through the framework of process maps establishing correlations among process, microstructure, and properties and providing opportunities for optimization of TBCs.

  11. Influence of powder and spray parameters on erosion and corrosion properties of HVOF sprayed WC-Co-Cr coatings

    Energy Technology Data Exchange (ETDEWEB)

    Berget, John

    1998-07-01

    Thermal spraying is a generic term including various processes used to deposit coatings on surfaces. The coating material is in the form of powder or a wire and is melted or softened by means of a heat source. A gas stream accelerates the material towards a prepared surface and deposits it there to form the coating. Examples of components being maintained by application of thermal spray coatings are gate valves and ball valves for the offshore industry and turbine blades in power generations installations. Recent investigation has shown that the commonly used coating material WC-Co is not corrosion resistant. But it can be improved by the addition of Cr. The main objective of this thesis is to study the influence of spray process control variables and powder characteristics on the erosion and erosion-corrosion properties of the coatings. Spray process variables investigated include energy input, powder feed rate and spray distance. Powder characteristics studied are average size of the WC particles, relative proportions of Co and Cr in the metal phase and powder grain size distribution.

  12. Sliding friction and wear behaviors of surface-coated natural serpentine mineral powders as lubricant additive

    International Nuclear Information System (INIS)

    Zhang Baosen; Xu Yi; Gao Fei; Shi Peijing; Xu Binshi; Wu Yixiong

    2011-01-01

    This work aims to investigate the friction and wear properties of surface-coated natural serpentine powders (SP) suspended in diesel engine oil using an Optimal SRV oscillating friction and wear tester. The worn surface was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Results indicated that the additives can improve the wear resistance and decrease friction coefficient of carbon steel friction couples. The 0.5 wt% content of serpentine powders is found most efficient in reducing friction and wear at the load of 50 N. The SEM and XPS analysis results demonstrate that a tribofilm forms on the worn surface, which is responsible for the decrease in friction and wear, mainly with iron oxides, silicon oxides, graphite and organic compounds.

  13. Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate.

    Science.gov (United States)

    Qu, Li; Zhou, Qi Tony; Gengenbach, Thomas; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Gamlen, Michael; Morton, David A V

    2015-05-01

    Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate.

  14. Applicability of Al-powder-alloy coating to corrosion barriers of 316SS in liquid lead-bismuth eutectic

    International Nuclear Information System (INIS)

    Kurata, Yuji; Sato, Hidetomo; Yokota, Hitoshi; Suzuki, Tetsuya

    2011-01-01

    A new Al-alloy coating method using Al, Ti and Fe powders has been applied to 316SS in order to develop corrosion resistant coating in liquid lead-bismuth eutectic (LBE). The 316SS plates with coating layers of different Al concentrations were exposed to liquid LBE with controlled oxygen concentrations of 10 -6 to 10 -4 mass% at 823 K for 3600 ks. While surface oxidation and grain boundary corrosion accompanied by liquid LBE penetration are observed in 316SS without Al-alloy coating, the Al-alloy coating is effective to protect such severe corrosion attacks in liquid LBE. Although the coating layer containing 2.8 mass% Al does not always keep sufficient corrosion resistance, good corrosion resistance is obtained through the Al-oxide film formed in liquid LBE in the coating layer where the average Al concentration is 4.2 mass%. Cracks are formed in the coating layer containing 17.8 mass% Al during the coating process. The Al-powder-alloy coating applied to 316SS is promising as a corrosion resistant coating method in liquid LBE environment. (author)

  15. Influence of hydroxyapatite coating thickness and powder particle size on corrosion performance of MA8M magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sonmez, S. [Hakkari University, Dept. of Biomedical Eng., 30000 Hakkari (Turkey); Aksakal, B., E-mail: baksakal@yildiz.edu.tr [Yildiz Technical University, Chemical Metallurgy Faculty, Dept. of Metall and Mater Eng., Istanbul (Turkey); Dikici, B. [Yuzuncu Yil University, Dept. of Mechanical Eng., 65080 Van (Turkey)

    2014-05-01

    Graphical abstract: The corrosion resistance of magnesium alloys is the primary concern in biomedical applications. Micron and nano-scale hydroxyapatite (HA) was coated successfully on MA8M magnesium alloy substrates by using a sol–gel deposition. In this study, the effects of coating thicknesses and HA powder particle sizes on the adhesion strength and corrosion behavior were investigated. Potentiodynamic polarization tests were performed in a Ringer solution. The coatings before and after corrosion tests were characterized by adhesion tests, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The micro-scale-HA coated Mg substrates were more corrosion resistant than the nano-scale-HA coatings. The anodic activity of the micro-scale-HA coatings increased with increased coating thickness and the corrosion resistance of Mg substrates decreased. Corrosion susceptibilities of the nano-scale-HA coated samples were affected inversely. The coated film provided good barrier characteristics and achieved good corrosion protection for Mg substrates when compared to substrates without coatings. For micro-scale-HA coatings, anodic and cathodic activities were more intense for thicker films. When HA coatings are compared to nano-scale HA coatings, the micro-scale-HA coatings produced better current density values. Overall, as shown in Fig. 1, the best corrosion behavior of the Mg alloys was achieved using micro-scale HA powders at 30 μm coating thickness. - Highlights: • Nano and micro-scale-HA coatings provided good anti-corrosion performance compared to the uncoated ones. • The micro-scale-HA coated Mg substrates were more corrosion resistant than the nano-scale-HA coatings. • The best corrosion behavior was achieved for the micro-scale HA powders at 30 μm coating thickness. • Anodic activity decrease and cathodic activity increase with increasing film thickness. - Abstract: To improve the corrosion resistance of MA8M magnesium alloy, sol

  16. Improvement of Surface Properties of Inconel718 by HVOF Coating with WC-Metal Powder and by Laser Heat Treatment of the Coating

    Directory of Open Access Journals (Sweden)

    Hui Gon Chun

    2015-01-01

    Full Text Available High-velocity oxygen-fuel (HVOF thermal spray coating with WC-metal powder was carried out by using optimal coating process on an Inconel718 surface for improvement of the surface properties, friction, wear, and corrosion resistance. Binder metals such as Cr and Ni were completely melted and WC was decomposed partially to W2C and graphite during the high temperature (up to 3500°C thermal spraying. The melted metals were bonded with WC and other carbides and were formed as WC-metal coating. The graphite and excessively sprayed oxygen formed carbon oxide gases, and these gases formed porous coating by evolution of the gases. The surface properties were improved by HVOF coating and were improved further by CO2 laser heat treatment (LH. Wear resistance of In718 surface was improved by coating and LH at 25°C and an elevated temperature of 450°C, resulting in reduction of wear trace traces, and was further improved by LH of the coating in reducing wear depth. Corrosion resistance due to coating in sea water was improved by LH. HVOF coating of WC-metal powder on a metal surface and a LH of the coating were highly recommended for the improvement of In718 surface properties, the friction behavior, and wear resistance.

  17. Influences of Processing and Fatigue Cycling on Residual Stresses in a NiCrY-Coated Powder Metallurgy Disk Superalloy

    Science.gov (United States)

    Gabb, T. P.; Rogers, R. B.; Nesbitt, J. A.; Miller, R. A.; Puleo, B. J.; Johnson, D.; Telesman, J.; Draper, S. L.; Locci, I. E.

    2017-11-01

    Oxidation and corrosion can attack superalloy disk surfaces exposed to increasing operating temperatures in some turbine engine environments. Any potential protective coatings must also be resistant to harmful fatigue cracking during service. The objective of this study was to investigate how residual stresses evolve in one such coating. Fatigue specimens of a powder metallurgy-processed disk superalloy were coated with a NiCrY coating, shot peened, and then subjected to fatigue in air at room and high temperatures. The effects of this processing and fatigue cycling on axial residual stresses and other aspects of the coating were assessed. While shot peening did induce beneficial compressive residual stresses in the coating and substrate, these stresses relaxed in the coating with subsequent heating. Several cast alloys having compositions near the coating were subjected to thermal expansion and tensile stress relaxation tests to help explain this response of residual stresses in the coating. For the coated fatigue specimens, this response contributed to earlier cracking of the coating than for the uncoated surface during long intervals of cycling at 760 °C. Yet, substantial compressive residual stresses still remained in the substrate adjacent to the coating, which were sufficient to suppress fatigue cracking there. The coating continued to protect the substrate from hot corrosion pitting, even after fatigue cracks initiated in the coating.

  18. Preparation and properties of thermal insulation coatings with a sodium stearate-modified shell powder as a filler

    Science.gov (United States)

    Tang, Qiang; Zhang, Ya-mei; Zhang, Pei-gen; Shi, Jin-jie; Tian, Wu-bian; Sun, Zheng-ming

    2017-10-01

    Waste shell stacking with odor and toxicity is a serious hazard to our living environment. To make effective use of the natural resources, the shell powder was applied as a filler of outdoor thermal insulation coatings. Sodium stearate (SS) was used to modify the properties of shell powder to reduce its agglomeration and to increase its compatibility with the emulsion. The oil absorption rate and the spectrum reflectance of the shell powder show that the optimized content of SS as a modifier is 1.5wt%. The total spectrum reflectance of the coating made with the shell powder that is modified at this optimum SS content is 9.33% higher than that without any modification. At the optimum SS content of 1.5wt%, the thermal insulation of the coatings is improved by 1.0°C for the cement mortar board and 1.6°C for the steel plate, respectively. The scouring resistance of the coating with the 1.5wt% SS-modified shell powder is three times that of the coating without modification.

  19. An analytical methodology to predict the coating characteristics of plasma-sprayed ceramic powders

    International Nuclear Information System (INIS)

    Varacalle, D.J. Jr.

    1990-01-01

    Experimental and analytical studies have been conducted at the Idaho National Engineering Laboratory (INEL) to investigate gas, particle, and coating dynamics in the plasma spray process. Nine experiments were conducted using a Taguchi statistical parametric approach. The thermal plasma produced by the commercial plasma spray torch and the related plasma/particle interaction were then numerically modeled from the cathode tip to varied standoff distances in the free plume for the nine experiments, which ranged in power from 28 to 43 kW. The flow and temperature fields in the plasma were solved using the governing conservation equations with suitable boundary conditions. This information was then used as boundary conditions to solve the plasma/particle interaction problem for the nine experiments. The particle dynamics (10- to 75-μm particles) for a yttria-stabilized zirconia powder were then simulated by computer. Particle morphology is discussed with respect to the changes in the process parameters. The predicted temperature and velocity of the zirconia particles were then used as initial conditions to a coating dynamics code. The code predicts the thickness and porosity of the zirconia coatings for the specific process parameters. The predicted coating characteristics exhibit reasonable correlation with the actual characteristics obtained from the Taguchi experimental studies. 12 refs., 7 figs., 6 tabs

  20. Influence of a powder feed rate on the properties of the plasma sprayed chromium carbide- 25% nickel chromium coating

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2014-04-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 The plasma spray process is a leading technology of powder depositing in the production of coatings widely used in the aerospace industry for the protection of new parts and for the repair of worn ones. Cermet 75Cr3C2 - 25Ni(Cr coatings based on Cr3C2 carbides are widely used to protect parts as they retain high values of hardness, strength and resistance to wear up to a temperature of 850°C. This paper discusses the influence of the parameters of the plasma spray deposition of 75Cr3C2 - 25Ni(Cr powder on the structure and mechanical properties of the coating. The powder is deposited using plasma spraying at atmospheric pressure (APS. The plasma gas is He, which is an inert gas and does not react with the powder; it produces dense plasma with lower heat content and less incorporated ambient air in the plasma jet thus reducing temperature decomposition and decarburization of Cr3C2 carbide.. In this study, three groups of coatings were deposited with three different powder feed rates of: 30, 45 and 60 g/min. The  coating with the best properties was deposited on the inlet flange parts of the turbo - jet engine TV2-117A to reduce the influence of vibrations and wear. The structures and the mechanical properties of 75Cr3C2 - 25Ni(Cr coatings are analyzed in accordance with the Pratt & Whitney standard. Studies have shown that powder feed rates have an important influence on the mechanical properties and structures of 75Cr3C2 - 25Ni(Cr coatings

  1. Dry coating of micronized API powders for improved dissolution of directly compacted tablets with high drug loading.

    Science.gov (United States)

    Han, Xi; Ghoroi, Chinmay; Davé, Rajesh

    2013-02-14

    Motivated by our recent study showing improved flow and dissolution rate of the active pharmaceutical ingredient (API) powders (20 μm) produced via simultaneous micronization and surface modification through continuous fluid energy milling (FEM) process, the performance of blends and direct compacted tablets with high drug loading is examined. Performance of 50 μm API powders dry coated without micronization is also considered for comparison. Blends of micronized, non-micronized, dry coated or uncoated API powders at 30, 60 and 70% drug loading, are examined. The results show that the blends containing dry coated API powders, even micronized ones, have excellent flowability and high bulk density compared to the blends containing uncoated API, which are required for direct compaction. As the drug loading increases, the difference between dry coated and uncoated blends is more pronounced, as seen in the proposed bulk density-FFC phase map. Dry coating led to improved tablet compactibility profiles, corresponding with the improvements in blend compressibility. The most significant advantage is in tablet dissolution where for all drug loadings, the t(80) for the tablets with dry coated APIs was well under 5 min, indicating that this approach can produce nearly instant release direct compacted tablets at high drug loadings. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. TiO2-enriched polymeric powder coatings support human mesenchymal cell spreading and osteogenic differentiation

    International Nuclear Information System (INIS)

    Mozumder, Mohammad Sayem; Zhu, Jesse; Perinpanayagam, Hiran

    2011-01-01

    Novel polymeric powder coatings (PPC) were prepared by ultrafine powder coating technology and shown to support human mesenchymal cell attachment and growth. PPC surfaces enriched with nano-TiO 2 (nTiO 2 ) showed enhanced cellular responses, and were compared to commercially pure titanium (cpTi). After cell attachment and growth, osteogenic differentiation and bone matrix formation ensures osseointegration for implantable biomaterials. Therefore, the objective of this study was to determine if mesenchymal cells grown on PPC could undergo osteogenic differentiation by inducing Runx2 and bone matrix proteins, and then initiate mineralization. Atomic force microscopy revealed intricate three-dimensional micro-topographies, and the measures of nano-roughness and porosity were similar for all PPC surfaces. Scanning electron microscopy showed that the cells attached and spread out over all of the surfaces. After 1 week in osteogenic media, RT-PCR analysis showed the induction of Runx2, the up-regulation of type I collagen, and the initial detection of alkaline phosphatase and bone sialoprotein. After 4 weeks, Alizarin Red staining showed mineral deposition. However, cell spreading and osteogenic differentiation were significantly (P 2 additives may enhance their performance.

  3. Synthesis of Yttria-stabilized zirconia nanoparticles by decomposition of metal nitrates coated on carbon powder

    International Nuclear Information System (INIS)

    Jiang, S.; Stangle, G.C.; Amarakoon, V.R.; Schulze, W.A.

    1996-01-01

    Weakly agglomerated nanoparticles of yttria-stabilized zirconia (YSZ) were synthesized by a novel process which involved the decomposition of metal nitrates that had been coated on ultrafine carbon black powder, after which the carbon black was gasified. The use of ultrafine, high-surface-area carbon black powder apparently allowed the nanocrystalline oxide particles to form and remain separate from each other, after which the carbon black was gasified at a somewhat higher temperature. As a result, the degree of agglomeration was shown to be relatively low. The average crystallite size and the specific surface area of the as-synthesized YSZ nanoparticles were 5∼6 nm and 130 m 2 /g, respectively, for powder synthesized at 650 degree C. The as-synthesized YSZ nanoparticles had a light brown color and were translucent, which differs distinctly from conventional YSZ particles which are typically white and opaque. The mechanism of the synthesis process was investigated, and indicated that the gasification temperature had a direct effect on the crystallite size of the as-synthesized YSZ nanoparticles. High-density and ultrafine-grained YSZ ceramic articles were prepared by fast-firing, using a dwell temperature of 1250 degree C and a dwell time of two minutes or less. copyright 1996 Materials Research Society

  4. Multi-layered electroless Ni-P coatings on powder-sintered Nd-Fe-B permanent magnet

    International Nuclear Information System (INIS)

    Chen Zhong; Ng, Alice; Yi Jianzhang; Chen Xingfu

    2006-01-01

    This paper has shown a successful protective coating scheme for powder-sintered Nd-Fe-B permanent magnet using multi-layered electroless nickel (EN) deposition. A low-phosphorus nickel layer is plated with an alkaline EN solution first, followed by a high-phosphorus nickel layer plated with an acidic solution. An additional topcoat by medium-phosphorus nickel on the high-phosphorus coating is also explored. It is shown that the high-phosphorus nickel layer coated in acidic solution provides the best corrosion protection because of its dense amorphous structure. The medium phosphorus topcoat is also dense and is able to provide reasonable corrosion resistance. The low-phosphorus layer itself does not have enough corrosion resistance; its main role is to provide an intermediate coating on the powder-sintered magnet. X-ray diffraction measurement shows that the low-phosphorus coating consists of nano-crystallines, and the high- and the medium-phosphorus coatings are dominated by amorphous structure. Microscopic observation and scratch test on these composite coatings demonstrate good adhesion between the magnet and the coatings. Remanence and coercivity of the plated magnet decrease with the applied coatings, but measured values are still very attractive for practical applications among known hard magnets

  5. Wear-resistance investigation of electro-screen coatings obtained using electroerosive powders of micro and nanofractions

    Science.gov (United States)

    Ageev, E. V.; Altukhov, A. Yu; Malneva, Yu V.; Novikov, A. N.

    2018-03-01

    The results of the wear resistance investigation of electro sparking coatings, applied using electrode material from electroerosive powders of hard alloy VK-8 (90%) with the addition of powder of high-speed steel of grade R6M5 (10%), are presented. Electro spark coatings were formed on samples of 30KhGSA steel using these electrodes and installation UR-121. The coefficient of friction and the wear rate of the surface of the sample and counterbody were measured on an automated friction machine “Tribometer” (CSM Instruments, Switzerland), controlled by a computer, according to the standard “ball-disk” test scheme.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-25

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

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  8. The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

    International Nuclear Information System (INIS)

    Jegdic, B.V.; Bajat, J.B.; Popic, J.P.; Stevanovic, S.I.; Miskovic-Stankovic, V.B.

    2011-01-01

    Highlights: → The effect of NaNO 2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO 2 . → EIS results and microscopic examinations correlate well with adhesion measurements. - Abstract: The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO 2 as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM). The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO 2 -free bath.

  9. Sustained release vancomycin-coated titanium alloy using a novel electrostatic dry powder coating technique may be a potential strategy to reduce implant-related infection.

    Science.gov (United States)

    Han, Jing; Yang, Yi; Lu, Junren; Wang, Chenzhong; Xie, Youtao; Zheng, Xuebin; Yao, Zhenjun; Zhang, Chi

    2017-07-24

    In order to tackle the implant-related infection, a novel way was developed in this study to coat vancomycin particles mixed with controlled release coating materials onto the surface of titanium alloy by using an electrostatic dry powder coating technique. To characterize this sustained release antibacterial coating, surface morphology, in vitro and in vivo drug release were sequentially evaluated. In vitro cytotoxicity was tested by Cell Counting Kit-8 (CCK-8) assay and cytological changes were observed by inverted microscope. The antibacterial properties against MRSA, including a bacterial growth inhibition assay and a colony-counting test by spread plate method were performed. Results indicated that the vancomycin-coated sample was biocompatible for Human osteoblast cell line MG-63 and displayed effective antibacterial ability against MRSA. The coating film was revealed uniform by scanning electron microscopy. Both the in vitro and in vivo drug release kinetics showed an initially high release rate, followed by an extended period of sustained drug release over 7 days. These results suggest that with good biocompatibility and antibacterial ability, the sustained release antibacterial coating of titanium alloy using our novel electrostatic dry powder coating process may provide a promising candidate for the treatment of orthopedic implant-related infection.

  10. Evaluating impacts of organizational intelligence in creating competitive strategy in companies producing powder coating

    Directory of Open Access Journals (Sweden)

    Somaye Nasiri

    2013-03-01

    Full Text Available Organizational intelligence (OI plays an important role on creating competitive strategy. This paper measure the effect of OI differentiation through value chain of organizational activities. The proposed study is applied in companies, which are active in the field of producing powder coating. Literature and background of research was reviewed to compile theoretical framework of the research model and after conducting library studies and performing exploratory interviews, important factors influencing OI on various sectors of the organization were extracted. In the same direction, these components were assessed through survey research and questionnaire tool. The proposed study uses structural equation modeling is implemented to study the effects of various factors and the validity of relationship among components was confirmed through a conceptual model.

  11. A novel approach using powder metallurgy for strengthened RABiTS composite substrates for coated superconductors

    International Nuclear Information System (INIS)

    Suo Hongli; Zhao Yue; Liu Min; Ye Shuai; Zhu YongHua; He Dong; Ma Lingji; Ji Yuan; Zhou Meiling

    2008-01-01

    We report on the development of mechanically strengthened, highly textured Ni-5 at.%W/Ni-12 at.%W composite materials prepared by a powder metallurgical approach as promising weakly magnetic substrates for coated superconductors. The key configuration of this composite substrate consists of a thin, sharp cubic textured Ni-5 at.%W layer on a Ni-12 at.%W alloy core, thus providing a mechanical reinforcement while decreasing the saturation magnetization of the whole substrate. The composite substrates have a sharp cubic texture at the top Ni-5 at.%W outer layer and their yield strength reaches 272 MPa, exceeding that of the commercially used Ni5W substrates by a factor of 1.6. The saturation magnetization of the composite substrate Ni5W/Ni12W/Ni5W is substantially reduced when compared to that of pure Ni and Ni-5 at.%W substrates, respectively

  12. Superhydrophobic photocatalytic PTFE – Titania coatings deposited by reactive pDC magnetron sputtering from a blended powder target

    Energy Technology Data Exchange (ETDEWEB)

    Ratova, Marina, E-mail: marina_ratova@hotmail.com; Kelly, Peter J.; West, Glen T.

    2017-04-01

    The production of photocatalytic coatings with superhydrophobic properties, as opposed to the conventional hydrophilic properties, is desirable for the prevention of adhesion of contaminants to photocatalytic surfaces with subsequent deterioration of photocatalytic properties. In this work polytetrafluoroethylene (PTFE) – TiO{sub 2} composite thin films were deposited using a novel method of reactive pulsed direct current (pDC) magnetron sputtering of a blended PTFE – titanium oxide powder target. The surface characteristics and photocatalytic properties of the deposited composite coatings were studied. The as-deposited coatings were annealed at 523 K in air and analysed with Raman spectroscopy, optical profilometry and scanning electron microscopy. Hydrophobicity was assessed though measurements of water contact angles, and photocatalytic properties were studied via methylene blue dye degradation under UV irradiation. It was found that variations of gas flow and, hence, process pressures allowed deposition of samples combining superhydrophobicity with stable photocatalytic efficiency under UV light irradiation. Reversible wettability behaviour was observed with the alternation of light-dark cycles. - Highlights: • PTFE-TiO{sub 2} coatings were deposited by pDC reactive magnetron sputtering. • Blended powder target was used for coatings deposition. • Deposited coatings combined superhydrophobic and photocatalytic properties. • Under UV irradiation coatings exhibited reversible wettability.

  13. Preparation of TiO2 Nanocrystallite Powders Coated with 9 mol% ZnO for Cosmetic Applications in Sunscreens

    Directory of Open Access Journals (Sweden)

    Moo-Chin Wang

    2012-02-01

    Full Text Available The preparation of TiO2 nanocrystallite powders coated with and without 9 mol% ZnO has been studied for cosmetic applications in sunscreens by a co-precipitation process using TiCl4 and Zn(NO32·6H2O as starting materials. XRD results show that the phases of anatase TiO2 and rutile TiO2 coexist for precursor powders without added ZnO (T-0Z and calcined at 523 to 973 K for 2 h. When the T-0Z precursor powders are calcined at 1273 K for 2 h, only the rutile TiO2 appears. In addition, when the TiO2 precursor powders contain 9 mol% ZnO (T-9Z are calcined at 873 to 973 K for 2 h, the crystallized samples are composed of the major phase of rutile TiO2 and the minor phases of anatase TiO2 and Zn2Ti3O8. The analyses of UV/VIS/NIR spectra reveal that the absorption of the T-9Z precursor powders after being calcined has a red-shift effect in the UV range with increasing calcination temperature. Therefore, the TiO2 nanocrystallite powders coated with 9 mol% ZnO can be used as the attenuate agent in the UV-A region for cosmetic applications in sunscreens.

  14. Study on microstructure change of Uranium nitride coated U-7wt%Mo powder by heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Woo Hyoung; Park, Jae Soon; Lee, Hae In; Kim, Woo Jeong; Yang, Jae Ho; Park, Jong Man [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    Uranium-molybdenum alloy particle dispersion fuel in an aluminum matrix with a high uranium density has been developed for a high performance research reactor in the RERTR program. In order to retard the fuel-matrix interaction in U-Mo/Al dispersion fuel in which the U-Mo fuel particles were dispersed in Al matrix, nitride layer coated U-Mo fuel particle has been designed and techniques to fabricate nitride-layer coated U-7wt%Mo particles have been developed in our lab. In this study, uranium nitride coated U-Mo particle has heat treatment for several times and degree. And we suggested for interaction layer remedy in U-Mo dispersion fuel. We investigate effect of heat treatment interaction layer evolution on uranium nitride coated U-Mo powder. The EDS and XRD analysis to investigate the phase evolution in uranium nitride coated layer is also a part of the present work

  15. Development of Nitride Coating Using Atomic Layer Deposition for Low-Enriched Uranium Fuel Powder

    Science.gov (United States)

    Bhattacharya, Sumit

    High-performance research reactors require fuel that operates at high specific power and can withstand high fission density, but at relatively low temperatures. The design of the research reactor fuels is done for efficient heat emission, and consists of assemblies of thin-plates cladding made from aluminum alloy. The low-enriched fuels (LEU) were developed for replacing high-enriched fuels (HEU) for these reactors necessitates a significantly increased uranium density in the fuel to counterbalance the decrease in enrichment. One of the most promising new fuel candidate is U-Mo alloy, in a U-Mo/Al dispersion fuel form, due to its high uranium loading as well as excellent irradiation resistance performance, is being developed extensively to convert from HEU fuel to LEU fuel for high-performance research reactors. However, the formation of an interaction layer (IL) between U-Mo particles and the Al matrix, and the associated pore formation, under high heat flux and high burnup conditions, degrade the irradiation performance of the U-Mo/Al dispersion fuel. From the recent tests results accumulated from the surface engineering of low enriched uranium fuel (SELENIUM) and MIR reactor displayed that a surface barrier coating like physical vapor deposited (PVD) zirconium nitride (ZrN) can significantly reduce the interaction layer. The barrier coating performed well at low burn up but above a fluence rate of 5x 1021 ions/cm2 the swelling reappeared due to formation interaction layer. With this result in mind the objective of this research was to develop an ultrathin ZrN coating over particulate uranium-molybdenum nuclear fuel using a modified savannah 200 atomic layer deposition (ALD) system. This is done in support of the US Department of Energy's (DOE) effort to slow down the interaction at fluence rate and reach higher burn up for high power research reactor. The low-pressure Savannah 200 ALD system is modified to be designed as a batch powder coating system using the

  16. Influence of Metal-Coated Graphite Powders on Microstructure and Properties of the Bronze-Matrix/Graphite Composites

    Science.gov (United States)

    Zhao, Jian-hua; Li, Pu; Tang, Qi; Zhang, Yan-qing; He, Jian-sheng; He, Ke

    2017-02-01

    In this study, the bronze-matrix/x-graphite (x = 0, 1, 3 and 5%) composites were fabricated by powder metallurgy route by using Cu-coated graphite, Ni-coated graphite and pure graphite, respectively. The microstructure, mechanical properties and corrosive behaviors of bronze/Cu-coated-graphite (BCG), bronze/Ni-coated-graphite (BNG) and bronze/pure-graphite (BPG) were characterized and investigated. Results show that the Cu-coated and Ni-coated graphite could definitely increase the bonding quality between the bronze matrix and graphite. In general, with the increase in graphite content in bronze-matrix/graphite composites, the friction coefficients, ultimate density and wear rates of BPG, BCG and BNG composites all went down. However, the Vickers microhardness of the BNG composite would increase as the graphite content increased, which was contrary to the BPG and BCG composites. When the graphite content was 3%, the friction coefficient of BNG composite was more stable than that of BCG and BPG composites, indicating that BNG composite had a better tribological performance than the others. Under all the values of applied loads (10, 20, 40 and 60N), the BCG and BNG composites exhibited a lower wear rate than BPG composite. What is more, the existence of nickel in graphite powders could effectively improve the corrosion resistance of the BNG composite.

  17. Improvement of deposition efficiency and control of hardness for cold-sprayed coatings using high carbon steel/mild steel mixture powder

    International Nuclear Information System (INIS)

    Ogawa, Kazuhiro; Amao, Satoshi; Yokoyama, Nobuyuki; Ootaki, Kousuke

    2011-01-01

    In this study, in order to make high carbon steel coating by cold spray technique, spray conditions such as carrier gas temperature and pressure etc. were investigated. And also, in order to improve deposition efficiency and control coating hardness of cold-sprayed high carbon steel, high carbon and mild steel mixed powder and its mechanical milled powder were developed and were optimized. By using the cold-spray technique, particle deposition of a high carbon steel was successful. Moreover, by applying mixed and mechanical milled powders, the porosity ratio was decreased and deposition efficiency was improved. Furthermore, using these powders, it is possible to control the hardness value. Especially, when using mechanical milled powder, it is very difficult to identify the interface between the coating and the substrate. The bonding between the coating and the substrate is thus considered to be excellent. (author)

  18. Effect of powders refinement on the tribological behavior of Ni-based composite coatings by laser cladding

    International Nuclear Information System (INIS)

    Wang Lingqian; Zhou Jiansong; Yu Youjun; Guo Chun; Chen Jianmin

    2012-01-01

    NiCr + Cr 3 C 2 + Ag + BaF 2 /CaF 2 composite coatings were produced on stainless steel (1Cr18Ni9Ti) substrates by laser cladding. Corresponding powders were prepared by high-energy ball milling technique. The friction and wear behavior at room temperature was investigated through sliding against the Si 3 N 4 ball. The morphologies of the wear debris, worn surfaces of both samples and the Si 3 N 4 ball were analyzed by scanning electron microscopy and three dimensional non-contact surface mapping. Results showed that milling time had a great effect on the size, morphology, uniformity of the powders as well as the microstructure and properties of laser cladding coatings. The wear mechanism of the coatings is dominated by abrasive wear, plastic deformation and slight adhesive wear. The consecutive evolution trend of friction coefficient, wear rate as well as microhardness of the serials of coatings produced with powders of different sizes was presented.

  19. Effect of powders refinement on the tribological behavior of Ni-based composite coatings by laser cladding

    Science.gov (United States)

    Wang, Lingqian; Zhou, Jiansong; Yu, Youjun; Guo, Chun; Chen, Jianmin

    2012-06-01

    NiCr + Cr3C2 + Ag + BaF2/CaF2 composite coatings were produced on stainless steel (1Cr18Ni9Ti) substrates by laser cladding. Corresponding powders were prepared by high-energy ball milling technique. The friction and wear behavior at room temperature was investigated through sliding against the Si3N4 ball. The morphologies of the wear debris, worn surfaces of both samples and the Si3N4 ball were analyzed by scanning electron microscopy and three dimensional non-contact surface mapping. Results showed that milling time had a great effect on the size, morphology, uniformity of the powders as well as the microstructure and properties of laser cladding coatings. The wear mechanism of the coatings is dominated by abrasive wear, plastic deformation and slight adhesive wear. The consecutive evolution trend of friction coefficient, wear rate as well as microhardness of the serials of coatings produced with powders of different sizes was presented.

  20. Effect of powders refinement on the tribological behavior of Ni-based composite coatings by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lingqian [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong, E-mail: jszhou@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yu Youjun; Guo Chun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2012-06-15

    NiCr + Cr{sub 3}C{sub 2} + Ag + BaF{sub 2}/CaF{sub 2} composite coatings were produced on stainless steel (1Cr18Ni9Ti) substrates by laser cladding. Corresponding powders were prepared by high-energy ball milling technique. The friction and wear behavior at room temperature was investigated through sliding against the Si{sub 3}N{sub 4} ball. The morphologies of the wear debris, worn surfaces of both samples and the Si{sub 3}N{sub 4} ball were analyzed by scanning electron microscopy and three dimensional non-contact surface mapping. Results showed that milling time had a great effect on the size, morphology, uniformity of the powders as well as the microstructure and properties of laser cladding coatings. The wear mechanism of the coatings is dominated by abrasive wear, plastic deformation and slight adhesive wear. The consecutive evolution trend of friction coefficient, wear rate as well as microhardness of the serials of coatings produced with powders of different sizes was presented.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  2. Wear and Adhesive Failure of Al2O3 Powder Coating Sprayed onto AISI H13 Tool Steel Substrate

    Science.gov (United States)

    Amanov, Auezhan; Pyun, Young-Sik

    2016-07-01

    In this study, an alumina (Al2O3) ceramic powder was sprayed onto an AISI H13 hot-work tool steel substrate that was subjected to sanding and ultrasonic nanocrystalline surface modification (UNSM) treatment processes. The significance of the UNSM technique on the adhesive failure of the Al2O3 coating and on the hardness of the substrate was investigated. The adhesive failure of the coating sprayed onto sanded and UNSM-treated substrates was investigated by a micro-scratch tester at an incremental load. It was found, based on the obtained results, that the coating sprayed onto the UNSM-treated substrate exhibited a better resistance to adhesive failure in comparison with that of the coating sprayed onto the sanded substrate. Dry friction and wear property of the coatings sprayed onto the sanded and UNSM-treated substrates were assessed by means of a ball-on-disk tribometer against an AISI 52100 steel ball. It was demonstrated that the UNSM technique controllably improved the adhesive failure of the Al2O3 coating, where the critical load was improved by about 31%. Thus, it is expected that the application of the UNSM technique to an AISI H13 tool steel substrate prior to coating may delay the adhesive failure and improve the sticking between the coating and the substrate thanks to the modified and hardened surface.

  3. Effects of Coating Materials and Processing Conditions on Flow Enhancement of Cohesive Acetaminophen Powders by High-Shear Processing With Pharmaceutical Lubricants.

    Science.gov (United States)

    Wei, Guoguang; Mangal, Sharad; Denman, John; Gengenbach, Thomas; Lee Bonar, Kevin; Khan, Rubayat I; Qu, Li; Li, Tonglei; Zhou, Qi Tony

    2017-10-01

    This study has investigated the surface coating efficiency and powder flow improvement of a model cohesive acetaminophen powder by high-shear processing with pharmaceutical lubricants through 2 common equipment, conical comil and high-shear mixer. Effects of coating materials and processing parameters on powder flow and surface coating coverage were evaluated. Both Carr's index and shear cell data indicated that processing with the lubricants using comil or high-shear mixer substantially improved the flow of the cohesive acetaminophen powder. Flow improvement was most pronounced for those processed with 1% wt/wt magnesium stearate, from "cohesive" for the V-blended sample to "easy flowing" for the optimally coated sample. Qualitative and quantitative characterizations demonstrated a greater degree of surface coverage for high-shear mixing compared with comilling; nevertheless, flow properties of the samples at the corresponding optimized conditions were comparable between 2 techniques. Scanning electron microscopy images demonstrated different coating mechanisms with magnesium stearate or l-leucine (magnesium stearate forms a coating layer and leucine coating increases surface roughness). Furthermore, surface coating with hydrophobic magnesium stearate did not retard the dissolution kinetics of acetaminophen. Future studies are warranted to evaluate tableting behavior of such dry-coated pharmaceutical powders. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  4. Finite element modelling of process-integrated powder coating by radial axial rolling of rings

    International Nuclear Information System (INIS)

    Frischkorn, J.; Kebriaei, R.; Reese, S.; Moll, H.; Theisen, W.; Husmann, T.; Meier, H.

    2011-01-01

    The process-integrated powder coating by radial axial rolling of rings represents a new hybrid production technique applied in the manufacturing of large ring-shaped work pieces with functional layers. It is thought to break some limitations that come along with the hot isostatic pressing (HIP) which is used nowadays to apply the powdery layer material onto the rolled substrate ring. Within the new process the compaction of the layer material is integrated into the ring rolling and HIP becomes dispensable. Following this approach the rolling of such compound rings brings up some new challenges. The volume of a solid ring stays nearly constant during the rolling. This behaviour can be exploited to determine the infeed of the rollers needed to reach the desired ring shape. Since volume consistency cannot be guaranteed for the rolling of a compound ring the choice of appropriate infeed of the rollers is still an open question. This paper deals with the finite element (FE) simulation of this new process. First, the material model that is used to describe the compaction of the layer material is shortly reviewed. The main focus of the paper is then put on a parameterized FE ring rolling model that incorporates a control system in order to stabilize the process. Also the differences in the behaviour during the rolling stage between a compound and a solid ring will be discussed by means of simulation results.

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

    International Nuclear Information System (INIS)

    Ishrat, S.; Nadeem, M.

    1993-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-22

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-05-01

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

  9. Microencapsulation of anthocyanin-rich black soybean coat extract by spray drying using maltodextrin, gum Arabic and skimmed milk powder.

    Science.gov (United States)

    Kalušević, Ana; Lević, Steva; Čalija, Bojan; Pantić, Milena; Belović, Miona; Pavlović, Vladimir; Bugarski, Branko; Milić, Jela; Žilić, Slađana; Nedović, Viktor

    2017-08-01

    Black soybean coat is insufficiently valorised food production waste rich in anthocyanins. The goal of the study was to examine physicochemical properties of spray dried extract of black soybean coat in regard to carrier materials: maltodextrin, gum Arabic, and skimmed milk powder. Maltodextrin and gum Arabic-based microparticles were spherical and non-porous while skimmed milk powder-based were irregularly shaped. Low water activity of microparticles (0.31-0.33), good powders characteristics, high solubility (80.3-94.3%) and encapsulation yields (63.7-77.0%) were determined. All microparticles exhibited significant antioxidant capacity (243-386 μmolTE/g), good colour stability after three months of storage and antimicrobial activity. High content of total anthocyanins, with cyanidin-3-glucoside as predominant, were achieved. In vitro release of anthocyanins from microparticles was sustained, particularly from gum Arabic-based. These findings suggest that proposed simple eco-friendly extraction and microencapsulation procedures could serve as valuable tools for valorisation and conversion of black soybean coat into highly functional and stable food colourant.

  10. Design of sustained release fine particles using two-step mechanical powder processing: particle shape modification of drug crystals and dry particle coating with polymer nanoparticle agglomerate.

    Science.gov (United States)

    Kondo, Keita; Ito, Natsuki; Niwa, Toshiyuki; Danjo, Kazumi

    2013-09-10

    We attempted to prepare sustained release fine particles using a two-step mechanical powder processing method; particle-shape modification and dry particle coating. First, particle shape of bulk drug was modified by mechanical treatment to yield drug crystals suitable for the coating process. Drug crystals became more rounded with increasing rotation speed, which demonstrates that powerful mechanical stress yields spherical drug crystals with narrow size distribution. This process is the result of destruction, granulation and refinement of drug crystals. Second, the modified drug particles and polymer coating powder were mechanically treated to prepare composite particles. Polymer nanoparticle agglomerate obtained by drying poly(meth)acrylate aqueous dispersion was used as a coating powder. The porous nanoparticle agglomerate has superior coating performance, because it is completely deagglomerated under mechanical stress to form fine fragments that act as guest particles. As a result, spherical drug crystals treated with porous agglomerate were effectively coated by poly(meth)acrylate powder, showing sustained release after curing. From these findings, particle-shape modification of drug crystals and dry particle coating with nanoparticle agglomerate using a mechanical powder processor is expected as an innovative technique for preparing controlled-release coated particles having high drug content and size smaller than 100 μm. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Production of nanocrystalline cermet thermal spray powders for wear resistant coatings by high-energy milling

    International Nuclear Information System (INIS)

    Eigen, N.; Klassen, T.; Aust, E.; Bormann, R.; Gaertner, F.

    2003-01-01

    TiC-Ni based nanocrystalline cermet powders for thermal spraying were produced by high-energy milling. Milling experiments were performed in an attrition mill and a vibration mill in kilogram scale, and powder morphologies and microstructures were characterized using scanning electron microscopy, X-ray diffraction, and laser scattering for particle size analysis. Milling time and powder input were optimized with respect to the desired microstructure and particle sizes, and the results using both types of mill were compared. Powders with homogeneously dispersed hard phase particles below 300 nm could be produced in both mills. Additional processes for the refinement of powder morphology and particle size distribution are discussed

  12. Influence of powder particle injection velocity on the microstructure of Al-12Si/SiCp coatings produced by laser cladding

    NARCIS (Netherlands)

    Anandkumar, R.; Almeida, A.; Vilar, R.; Ocelik, V.; De Hosson, J. Th M.

    2009-01-01

    The influence of powder particle injection velocity on the microstructure of coatings consisting of an Al-Si matrix reinforced with SiC particles prepared by laser cladding from mixtures of powders of Al-12 wt.% Si alloy and SiC was investigated both experimentally and by modeling. At low injection

  13. Chitosan-coated liposome dry-powder formulations loaded with ghrelin for nose-to-brain delivery.

    Science.gov (United States)

    Salade, Laurent; Wauthoz, Nathalie; Vermeersch, Marjorie; Amighi, Karim; Goole, Jonathan

    2018-06-11

    The nose-to-brain delivery of ghrelin loaded in liposomes is a promising approach for the management of cachexia. It could limit the plasmatic degradation of ghrelin and provide direct access to the brain, where ghrelin's specific receptors are located. Anionic liposomes coated with chitosan in either a liquid or a dry-powder formulation were compared. The powder formulation showed stronger adhesion to mucins (89 ± 4% vs 61 ± 4%), higher ghrelin entrapment efficiency (64 ± 2% vs 55 ± 4%), higher enzymatic protection against trypsin (26 ± 2% vs 20 ± 3%) and lower ghrelin storage degradation at 25°C (2.67 ± 1.1% vs 95.64 ± 0.85% after 4 weeks). The powder formulation was also placed in unit-dose system devices that were able to generate an appropriate aerosol characterized by a Dv50 of 38 ± 6 µm, a limited percentage of particles smaller than 10 µm of 4 ± 1% and a reproducible mass delivery (CV: 1.49%). In addition, the device was able to deposit a large amount of powder (52.04% w/w) in the olfactory zone of a 3D-printed nasal cast. The evaluated combination of the powder formulation and the device could provide a promising treatment for cachexia. Copyright © 2018. Published by Elsevier B.V.

  14. Microstructure of bonding zones in laser-clad Ni-alloy-based composite coatings reinforced with various ceramic powders

    International Nuclear Information System (INIS)

    Pei, Y.T.; Ouyang, J.H.; Lei, T.C.

    1996-01-01

    Microstructure of the bonding zones (BZs) between laser-clad Ni-alloy-based composite coatings and steel substrates was studied by means of scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. Observations indicate that for pure Ni-alloy coating the laser parameters selected for good interface fusion have no effect on the microstructure of the BZ except for its thickness. However, the addition of ceramic particles (TiN, SiC, or ZrO 2 ) to the Ni alloy varies the compositional or constitutional undercooling of the melt near the solid/liquid interface and consequently leads to the observed changes of microstructure of the BZs. For TiN/Ni-alloy coating the morphology of γ-Ni solid solution in the BZ changes from dendritic to planar form with increasing scanning speed. A colony structure of eutectic is found in the BZ of SiC/Ni-alloy coating in which complete dissolution of SiC particles takes place during laser cladding. The immiscible melting of ZrO 2 and Ni-alloy powders induces the stratification of ZrO 2 /Ni-alloy coating which consists of a pure ZrO 2 layer fin the upper region and a BZ composed mainly of γ-Ni dendrites adjacent to the substrate. All the BZs studied in this investigation have good metallurgical characteristics between the coatings and the substrates

  15. Single-step laser deposition of functionally graded coating by dual ‘wire powder’ or ‘powder powder’ feeding—A comparative study

    Science.gov (United States)

    Syed, Waheed Ul Haq; Pinkerton, Andrew J.; Liu, Zhu; Li, Lin

    2007-07-01

    The creation of iron-copper (Fe-Cu) alloys has practical application in improving the surface heat conduction and corrosion resistance of, for example, conformal cooling channels in steel moulds, but is difficult to achieve because the elements have got low inter-solubility and are prone to solidification cracking. Previous work by these authors has reported a method to produce a graded iron-nickel-copper coating in a single-step by direct diode laser deposition (DLD) of nickel wire and copper powder as a combined feedstock. This work investigates whether dual powder feeds can be used in that process to afford greater geometric flexibility and compares attributes of the 'nickel wire and copper powder' and 'nickel powder and copper powder' processes for deposition on a H13 tool steel substrate. In wire-powder deposition, a higher temperature developed in the melt pool causing a clad with a smooth gradient structure. The nickel powder in powder-powder deposition did not impart much heat into the melt pool so the melt pool solidified with sharp composition boundaries due to single metal melting in some parts. In wire-powder experiments, a graded structure was obtained by varying the flow rates of wire and powder. However, a graded structure was not realised in powder-powder experiments by varying either the feed or the directions. Reasons for the differences and flow patterns in the melt pools and their effect on final part properties of parts produced are discussed.

  16. Wear of Flame-Sprayed Ni-Cr-B-Si Powder Coating on Journal for Seal Contact

    Directory of Open Access Journals (Sweden)

    Hu Sheng-Yen

    2016-01-01

    Full Text Available Flame-sprayed techniques is used in this paper to coat Ni-Cr-B-Si powder on low-carbon steel or bearing steel materials of the journal surface. The wear tester is used to explore material properties of the binding capability, surface hardness, wear and friction within each layer depth. The normal force is applied in addition to the cladding layer by not only using bearing ball but also oil seal pieces, to explore rubber material of oil seal contact journal. In experiments to explore the material and processing conditions affect the microstructure and hardness of the cladding layer, and at the same hardness, surface roughness to affect the performance of the mill run.The results showed that spraying Ni-Cr-B-Si alloy powder in mild steel sheet to melt and run, cladding layer and the substrate has a uniform distribution of fine abrasive particles and binding effect, causing the substrate surface hardness (HRC about promotion 10 times. While, if sprayed Ni-Cr-B-Si alloy powder to steel panels bearing surface because the surface coated compact structure, can reduce the surface roughness and the coefficient of friction, and more improve the wear resistance of the cladding layer.

  17. The influence of concentration of Nd-Fe-B powder in composite coating of optical fiber to the sensibility to external magnetic field

    Directory of Open Access Journals (Sweden)

    Radojević Vesna J.

    2005-01-01

    Full Text Available Multi-mode optical fiber with magnetic composite coating was investigated as an optical fiber sensor element (OFMSE for magnetic field sensing The composite coating was formed with dispersions of permanent magnet powder of Nd-Fe-B in poly (ethylene-co-vinyl acetate-EVA solutions in toluene. The influence of the applied external magnetic field on the change of intensity of the light signal propagate trough developed optical fibers sensor element was investigated. In this paper the influence of the content of magnetic powder in the composite coating on the optical propagation characteristics of optical fiber were particularly investigated.

  18. Effect of nano Cu coating on porous Si prepared by acid etching Al-Si alloy powder

    International Nuclear Information System (INIS)

    Li, Chunli; Zhang, Ping; Jiang, Zhiyu

    2015-01-01

    As a promising anode material for lithium ion battery, nano-Cu coated porous Si powder was fabricated through two stages: first, preparation of porous nano Si fibers by acid-etching Al-Si alloy powder; second, modified by nano-Cu particles using an electroless plating method. The nano-Cu particles on the surface of nano-Si fibers, not only increase the conductivity of material, but also inhibit the fuse process between nano Si fibers during charge/discharge cycling process, resulting in increased cycling stability of the material. In 1 M LiPF 6 /EC: DMC (1:1) + 1.5 wt% VC solution at current density of 200 mA g −1 , the 150th discharge capacity of nano-Cu coated porous Si electrode was 1651 mAh g −1 with coulombic efficiency of 99%. As anode material for lithium ion battery, nano-Cu coated porous Si nano fiber material is easier to prepare, costs less, and produces higher performance, representing a promising approach for high energy lithium ion battery application

  19. Influence of polymeric subcoats on the drug release properties of tablets powder-coated with pre-plasticized Eudragit L 100-55.

    Science.gov (United States)

    Sauer, Dorothea; Watts, Alan B; Coots, Lonique B; Zheng, Weijia C; McGinity, James W

    2009-02-09

    The aim of the study was to investigate the properties of sodium valproate tablets that were dry powder-coated with pre-plasticized Eudragit L 100-55. Polyethylene glycol 3350 (PEG 3350) was used as primer to facilitate initial coating powder adhesion. Solubility parameters were employed to determine the wetting properties of the PEG 3350 primer. Additional PEG 3350 within the powder coating formulation was required to enable powder adhesion to the tablet cores. The application of a subcoat of either Eudragit E PO or Eudragit RL PO facilitated adhesion of the enteric polymer to the tablet cores and reduced the amount PEG 3350 required in the coating formulation. Since reduction of the PEG 3350 content produced less water-vapor permeable films, the enteric coating level necessary to control the drug release was decreased. PEG 3350 and Methocel K4M were incorporated in both Eudragit E PO and Eudragit RL PO subcoating formulations as pore forming agents. The influence of the pore forming excipients on physicochemical properties of free powder-cast films was investigated. The miscibility of the PEG 3350 and Methocel K4M in the film coating was correlated with their ability to function as pore forming agent.

  20. Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

    Science.gov (United States)

    Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-09-10

    In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Solventless dry powder coating for sustained drug release using mechanochemical treatment based on the tri-component system of acetaminophen, carnauba wax and glidant.

    Science.gov (United States)

    Hoashi, Yohei; Tozuka, Yuichi; Takeuchi, Hirofumi

    2013-02-01

    Solventless dry powder coating methods have many advantages compared to solvent-based methods: they are more economical, simpler, safer, more environmentally friendly and easier to scale up. The purpose of this study was to investigate a highly effective dry powder coating method using the mechanofusion system, a mechanochemical treatment equipped with high compressive and shearing force. Acetaminophen (AAP) and carnauba wax (CW) were selected as core particles of the model drug and coating material, respectively. Mixtures of AAP and CW with and without talc were processed using the mechanofusion system. Sustained AAP release was observed by selecting appropriate processing conditions for the rotation speed and the slit size. The dissolution rate of AAP processed with CW substantially decreased with an increase in talc content up to 40% of the amount of CW loaded. Increasing the coating amount by two-step addition of CW led to more effective coating and extended drug release. Scanning electron micrographs indicated that CW adhered and showed satisfactory coverage of the surface of AAP particles. Effective CW coating onto the AAP surface was successfully achieved by strictly controlling the processing conditions and the composition of core particles, coating material and glidant. Our mechanochemical dry powder coating method using the mechanofusion system is a simple and promising means of solventless pharmaceutical coating.

  2. High Thermal Dissipation of Al Heat Sink When Inserting Ceramic Powders by Ultrasonic Mechanical Coating and Armoring.

    Science.gov (United States)

    Tsai, Wei-Yu; Huang, Guan-Rong; Wang, Kuang-Kuo; Chen, Chin-Fu; Huang, J C

    2017-04-26

    Aluminum alloys, which serve as heat sink in light-emitting diode (LED) lighting, are often inherent with a high thermal conductivity, but poor thermal total emissivity. Thus, high emissive coatings on the Al substrate can enhance the thermal dissipation efficiency of radiation. In this study, the ultrasonic mechanical coating and armoring (UMCA) technique was used to insert various ceramic combinations, such as Al₂O₃, SiO₂, or graphite, to enhance thermal dissipation. Analytic models have been established to couple the thermal radiation and convection on the sample surface through heat flow equations. A promising match has been reached between the theoretical predictions and experimental measurements. With the adequate insertion of ceramic powders, the temperature of the Al heat sinks can be lowered by 5-11 °C, which is highly favorable for applications requiring cooling components.

  3. Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

    OpenAIRE

    Ivan Stojanović; Vinko Šimunović; Vesna Alar; Frankica Kapor

    2018-01-01

    Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC) content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispens...

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

    Science.gov (United States)

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

    2001-04-01

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

  5. Silicone-acrylic hybrid aqueous dispersions of core–shell particle structure and corresponding silicone-acrylic nanopowders designed for modification of powder coatings and plastics. Part III: Effect of modification with selected silicone-acrylic nanopowders on properties of polyurethane powder coatings

    Czech Academy of Sciences Publication Activity Database

    Pilch-Pitera, B.; Kozakiewicz, J.; Ofat, I.; Trzaskowska, J.; Špírková, Milena

    2015-01-01

    Roč. 78, January (2015), s. 429-436 ISSN 0300-9440 Institutional support: RVO:61389013 Keywords : polyurethanes * powder coatings * blocked polyisocyanates Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.632, year: 2015

  6. Improved 3-omega measurement of thermal conductivity in liquid, gases, and powders using a metal-coated optical fiber.

    Science.gov (United States)

    Schiffres, Scott N; Malen, Jonathan A

    2011-06-01

    A novel 3ω thermal conductivity measurement technique called metal-coated 3ω is introduced for use with liquids, gases, powders, and aerogels. This technique employs a micron-scale metal-coated glass fiber as a heater/thermometer that is suspended within the sample. Metal-coated 3ω exceeds alternate 3ω based fluid sensing techniques in a number of key metrics enabling rapid measurements of small samples of materials with very low thermal effusivity (gases), using smaller temperature oscillations with lower parasitic conduction losses. Its advantages relative to existing fluid measurement techniques, including transient hot-wire, steady-state methods, and solid-wire 3ω are discussed. A generalized n-layer concentric cylindrical periodic heating solution that accounts for thermal boundary resistance is presented. Improved sensitivity to boundary conductance is recognized through this model. Metal-coated 3ω was successfully validated through a benchmark study of gases and liquids spanning two-orders of magnitude in thermal conductivity. © 2011 American Institute of Physics

  7. Detonation wear-resistant coatings, alloy powders based on Cr-Si

    Directory of Open Access Journals (Sweden)

    А.Г. Довгаль

    2009-03-01

    Full Text Available  Coatings from composition material Cr-Si-B on steel by detonation spraying method are obtained. Composition, structure and tribotechnical characteristics of coatings in comparison with traditional materials on the basis of Ni-Cr and alloy of tungsten and cobalt are investigated.

  8. Microstructural and Mechanical Study of Inconel 625 – Tungsten Carbide Composite Coatings Obtained by Powder Laser Cladding

    Directory of Open Access Journals (Sweden)

    Huebner J.

    2017-06-01

    Full Text Available This study focuses on the investigation of fine (~0.54 μm tungsten carbide particles effect on structural and mechanical properties of laser cladded Inconel 625-WC composite. Three powder mixtures with different Inconel 625 – WC weight ratio (10, 20 and 30 weight % of WC were prepared. Coatings were made using following process parameters: laser beam diameter ø ≈ 500 μm, powder feeder rotation speed – 7 m/min, scanning velocity – 10 m/min, laser power – 220 W changed to 320 W, distance between tracks – 1 mm changed to 0.8 mm. Microstructure and hardness were investigated. Coatings produced by laser cladding were crack and pore free, chemically and structurally homogenous. High cooling rate during cladding process resulted in fine microstructure of material. Hardness improved with addition of WC from 396.3 ±10.5 HV for pure Inconel 625, to 469.9 ±24.9 HV for 30 weight % of WC. Tungsten carbide dissolved in Inconel 625 which allowed formation of intergranular eutectic that contains TCP phases.

  9. MICROSTRUCTURE AND WEAR PROPERTIES OF COMPOSITE COATINGS PRODUCED BY LASER CLADDING OF Ti-6Al-4V WITH GRAPHITE AND SILICON MIXED POWDERS

    OpenAIRE

    Y. S. TIAN; C. Z. CHEN; D. Y. WANG; Q. H. HUO; T. Q. LEI

    2005-01-01

    Composite coatings are fabricated by laser cladding of titanium alloy Ti-6Al-4V with graphite and silicon mixed powders. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) indicate that the coatings mainly consist of pre-eutectic TiC and eutectic Ti5Si3 compounds. Test results show that the coatings exhibit a higher microhardness and a lower friction coefficient compared with the as-received sample. EPMA micrographs show that the compounds' morphology in the top zone of the coat...

  10. The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

    International Nuclear Information System (INIS)

    Emamian, Ali; Corbin, Stephen F.; Khajepour, Amir

    2012-01-01

    Highlights: ► The novel idea was to develop Fe-TiC containing high volume fraction of TiC. ► Increased TiC volume fraction enhanced clad hardness profile. ► Both, laser conditions and fed powder compositions affected the clad microstructure. ► Hardness and TiC volume fraction was maximized by control over melt pool composition. ► Hardness/TiC volume fraction was maximized by controlling of laser parameters. - Abstract: In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an Fe-Ti-based composition to an Fe-C-based one. Fe percentages of 70, 60, 50 and 10 wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45 at% to 55 at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.

  11. The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

    Energy Technology Data Exchange (ETDEWEB)

    Emamian, Ali, E-mail: aemamian@uwaterloo.ca [Research Associate and Postdoctoral fellow in the Department of Mechanics and Mechatronics, University of Waterloo, 200 University West, Waterloo, N2L 4 3G1 (Canada); Corbin, Stephen F. [Professor and Canada Research Chair in the Department of Civil and Resource Engineering, Dalhousie University, Halifax, Nova Scotia, P.O. Box 15000, B3H 5 4R2 (Canada); Khajepour, Amir [Professor and Canada Research Chair in the Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The novel idea was to develop Fe-TiC containing high volume fraction of TiC. Black-Right-Pointing-Pointer Increased TiC volume fraction enhanced clad hardness profile. Black-Right-Pointing-Pointer Both, laser conditions and fed powder compositions affected the clad microstructure. Black-Right-Pointing-Pointer Hardness and TiC volume fraction was maximized by control over melt pool composition. Black-Right-Pointing-Pointer Hardness/TiC volume fraction was maximized by controlling of laser parameters. - Abstract: In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an Fe-Ti-based composition to an Fe-C-based one. Fe percentages of 70, 60, 50 and 10 wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45 at% to 55 at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.

  12. High-performance characteristics of the bonded magnets produced from the Sm2 Fe17 Nx powder stabilized by photo-induced zinc metal coatings

    International Nuclear Information System (INIS)

    Machida, K.; Izumi, H.; Shiomi, A.; Iguchi, M.; Adachi, G.

    1996-01-01

    Finely and uniformly ground powders of Sm 2 Fe 17 N x were stabilized by surface-coating with the zinc metal produced from Zn (C 2 H 5 ) 2 . The epoxy resin-bonded magnets produced from the Zn/Sm 2 Fe 17 N x composite powder provided high-performance permanent magnetic characteristics: (BH)max=∼ 176 kJm -3 . (author)

  13. TiO{sub 2}-enriched polymeric powder coatings support human mesenchymal cell spreading and osteogenic differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Mozumder, Mohammad Sayem; Zhu, Jesse [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9 (Canada); Perinpanayagam, Hiran, E-mail: Hiran.Perinpanayagam@schulich.uwo.ca [Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1 (Canada)

    2011-06-15

    Novel polymeric powder coatings (PPC) were prepared by ultrafine powder coating technology and shown to support human mesenchymal cell attachment and growth. PPC surfaces enriched with nano-TiO{sub 2} (nTiO{sub 2}) showed enhanced cellular responses, and were compared to commercially pure titanium (cpTi). After cell attachment and growth, osteogenic differentiation and bone matrix formation ensures osseointegration for implantable biomaterials. Therefore, the objective of this study was to determine if mesenchymal cells grown on PPC could undergo osteogenic differentiation by inducing Runx2 and bone matrix proteins, and then initiate mineralization. Atomic force microscopy revealed intricate three-dimensional micro-topographies, and the measures of nano-roughness and porosity were similar for all PPC surfaces. Scanning electron microscopy showed that the cells attached and spread out over all of the surfaces. After 1 week in osteogenic media, RT-PCR analysis showed the induction of Runx2, the up-regulation of type I collagen, and the initial detection of alkaline phosphatase and bone sialoprotein. After 4 weeks, Alizarin Red staining showed mineral deposition. However, cell spreading and osteogenic differentiation were significantly (P < 0.05) higher on the cpTi controls than on the PPC surfaces. Furthermore, spreading and differentiation were consistently higher on the titanium-enriched PPC-2, -3 and -4 than on the titanium-free PPC-1. Therefore, despite the presence of complex micro-topographies and nano-features, titanium-enrichment enhanced the cellular response, and pure titanium still provided the best substrate. These findings confirm the cytocompatibility of these novel polymeric coatings and suggest that titanium-enrichment and nTiO{sub 2} additives may enhance their performance.

  14. Microwave absorption properties of a wave-absorbing coating employing carbonyl-iron powder and carbon black

    International Nuclear Information System (INIS)

    Liu Lidong; Duan Yuping; Ma Lixin; Liu Shunhua; Yu Zhen

    2010-01-01

    To prevent serious electromagnetic interference, a single-layer wave-absorbing coating employing complex absorbents composed of carbonyl-iron powder (CIP) and carbon black (CB) with epoxy resin as matrix was prepared. The morphologies of CIP and CB were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. The electromagnetic parameters of CIP and CB were measured in the frequency range of 2-18 GHz by transmission/reflection technology, and the electromagnetic loss mechanisms of the two particles were discussed, respectively. The microwave absorption properties of the coatings were investigated by measuring reflection loss (RL) using arch method. The effects of CIP ratio, CB content and thickness on the microwave absorption properties were discussed, respectively. The results showed that the higher thickness, CIP or CB content could make the absorption band shift towards the lower frequency range. Significantly, the wave-absorbing coating could be applied in different frequency ranges according to actual demand by controlling the content of CIP or CB in composites.

  15. Microwave absorption properties of a wave-absorbing coating employing carbonyl-iron powder and carbon black

    Science.gov (United States)

    Liu, Lidong; Duan, Yuping; Ma, Lixin; Liu, Shunhua; Yu, Zhen

    2010-11-01

    To prevent serious electromagnetic interference, a single-layer wave-absorbing coating employing complex absorbents composed of carbonyl-iron powder (CIP) and carbon black (CB) with epoxy resin as matrix was prepared. The morphologies of CIP and CB were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. The electromagnetic parameters of CIP and CB were measured in the frequency range of 2-18 GHz by transmission/reflection technology, and the electromagnetic loss mechanisms of the two particles were discussed, respectively. The microwave absorption properties of the coatings were investigated by measuring reflection loss (RL) using arch method. The effects of CIP ratio, CB content and thickness on the microwave absorption properties were discussed, respectively. The results showed that the higher thickness, CIP or CB content could make the absorption band shift towards the lower frequency range. Significantly, the wave-absorbing coating could be applied in different frequency ranges according to actual demand by controlling the content of CIP or CB in composites.

  16. Influence of Feedstock Powder Modification by Heat Treatments on the Properties of APS-Sprayed Al2O3-40% TiO2 Coatings

    Science.gov (United States)

    Berger, Lutz-Michael; Sempf, Kerstin; Sohn, Yoo Jung; Vaßen, Robert

    2018-04-01

    The formation and decomposition of aluminum titanate (Al2TiO5, tialite) in feedstock powders and coatings of the binary Al2O3-TiO2 system are so far poorly understood. A commercial fused and crushed Al2O3-40%TiO2 powder was selected as the feedstock for the experimental series presented in this paper, as the composition is close to that of Al2TiO5. Part of that powder was heat-treated in air at 1150 and 1500 °C in order to modify the phase composition, while not influencing the particle size distribution and processability. The powders were analyzed by thermal analysis, XRD and FESEM including EDS of metallographically prepared cross sections. Only a maximum content of about 45 wt.% Al2TiO5 was possible to obtain with the heat treatment at 1500 °C due to inhomogeneous distribution of Al and Ti in the original powder. Coatings were prepared by plasma spraying using a TriplexPro-210 (Oerlikon Metco) with Ar-H2 and Ar-He plasma gas mixtures at plasma power levels of 41 and 48 kW. Coatings were studied by XRD, SEM including EDS linescans of metallographically prepared cross sections, and microhardness HV1. With the exception of the powder heat-treated at 1500 °C an Al2TiO5-Ti3O5 (tialite-anosovite) solid solution Al2- x Ti1+ x O5 instead of Al2TiO5 existed in the initial powder and the coatings.

  17. Optimization of laser cladding of cold spray coatings with B4C and Ni powders

    Science.gov (United States)

    Fomin, V. M.; Golyshev, A. A.; Malikov, A. G.; Orishich, A. M.; Filippov, A. A.; Ryashin, N. S.

    2017-12-01

    In the present work, a combined method is considered for the production of a metal-matrix composite coating based on Ni and B4C. The coating is created by consistently applied methods: cold spray and laser cladding. The conditions of obtaining cermet layers are investigated depending on the parameters of laser cladding and cold spray. It is shown that the laser track structure significantly changes in accordance to the size of ceramic particles ranging 3-75 µm and its concentration. It is shown that the most perspective layers for additive manufacturing could be obtain from cold spray coatings with ceramic concentrations more than 50% by weight treated in the heat-conductivity laser mode.

  18. About properties of ZrO2 thermal protective coatings obtained from spherical powder mixtures

    Science.gov (United States)

    Berdnik, O. B.; Tsareva, I. N.; Tarasenko, Yu P.

    2017-05-01

    It is developed the technology of high-energy plasma spraying of the zirconium dioxide (ZrO2) thermal protective coating on the basis of ZrO2 tetragonal and cubic phases with the spheroidal grain shape and the columnar substructure, with the total porosity P = 4 %, the hardness HV = 12 GPa, the roughness parameter R a ˜ 6 μm, the thickness 0.3-3 mm. As a sublayer it is used the heat-resistant coating of “Ni-Co-Cr-Al-Y” system with an intermetallic phase composition and the layered microstructure of the grains.

  19. Design of conveyor utilization monitoring system: a case study of powder coating line in sheet metal fabrication

    Science.gov (United States)

    Prasetyo, Hoedi; Sugiarto, Yohanes; Nur Rosyidi, Cucuk

    2018-03-01

    Conveyor is a very useful equipment to replace manpower in transporting the goods. It highly influences the productivity, production capacity utilization and eventually the production cost. This paper proposes a system to monitor the utilization of conveyor at a low cost through a case study at powder coating process line in a sheet metal fabrication. Preliminary observation was conducted to identify the problems. The monitoring system was then built and executed. The system consists of two sub systems. First is sub system for collecting and transmitting the required data and the second is sub system for displaying the data. The system utilizes sensors, wireless data transfer and windows-based application. The test results showed that the whole system works properly. By this system, the productivity and status of the conveyor can be monitored in real time. This research enriches the development of conveyor monitoring system especially for implementation in small and medium enterprises.

  20. Influence of manganite powder grain size and Ag-particle coating on the magnetocaloric effect and the active magnetic regenerator performance

    DEFF Research Database (Denmark)

    Turcaud, J.A.; Neves Bez, Henrique; Ruiz-Trejo, E.

    2015-01-01

    The magnetocaloric performance of La0.67Ca0.27Sr0.06Mn1.05O3 is investigated as a function of the powder grain size and also as a function of decoration of grains with highly conductive silver particulates as a coating layer. We demonstrate that the thermal and electrical conductivities can be si...

  1. Supercritical CO2-Assisted Spray Drying of Strawberry-Like Gold-Coated Magnetite Nanocomposites in Chitosan Powders for Inhalation

    Directory of Open Access Journals (Sweden)

    Marta C. Silva

    2017-01-01

    Full Text Available Lung cancer is one of the leading causes of death worldwide. Therefore, it is of extreme importance to develop new systems that can deliver anticancer drugs into the site of action when initiating a treatment. Recently, the use of nanotechnology and particle engineering has enabled the development of new drug delivery platforms for pulmonary delivery. In this work, POXylated strawberry-like gold-coated magnetite nanocomposites and ibuprofen (IBP were encapsulated into a chitosan matrix using Supercritical Assisted Spray Drying (SASD. The dry powder formulations showed adequate morphology and aerodynamic performances (fine particle fraction 48%–55% and aerodynamic diameter of 2.6–2.8 µm for deep lung deposition through the pulmonary route. Moreover, the release kinetics of IBP was also investigated showing a faster release of the drug at pH 6.8, the pH of lung cancer. POXylated strawberry-like gold-coated magnetite nanocomposites proved to have suitable sizes for cellular internalization and their fluorescent capabilities enable their future use in in vitro cell based assays. As a proof-of-concept, the reported results show that these nano-in-micro formulations could be potential drug vehicles for pulmonary administration.

  2. Surface coatings of mixed hard alloy powder metals sintered-on in vacuo

    International Nuclear Information System (INIS)

    Knotek, O.; Reimann, H.

    1980-01-01

    No technological difficulties are to be encountered in the processing of pseudo hard alloys in the form of powder compounds of conventional nickel base hard alloys with carbides. There is a great alloy influence on the resulting structures of the surface layers. Under some processing conditions the tungsten carbide is completely dissolved from molten matrix alloy. Hard phases on chromium carbide basis resulted upon cooling. Induced chromium carbide Cr 3 C 2 retains its structure while absorbing large amounts of iron into its grid. It can be concluded that not only alloying properties, but also eminently structural criterions are decisive for the stability of the applied supplementary hard phases. (orig.) [de

  3. Microstructural Evolution of AlCoCrFeNiSi High-Entropy Alloy Powder during Mechanical Alloying and Its Coating Performance.

    Science.gov (United States)

    Tian, Lihui; Fu, Ming; Xiong, Wei

    2018-02-23

    High-entropy alloys (HEAs) are promising structural materials due to their excellent comprehensive performances. The use of mechanically alloyed powders to deposit HEA coatings through atmospheric plasma spraying (APS) is an effective approach that can broaden the application areas of the HEAs. In this paper, a ductility-brittleness AlCoCrFeNiSi system was chosen as an object of study, and the detailed evolution of the surface morphology, particle size distribution, and microstructure of the powder during mechanical alloying was investigated. An AlCoCrFeNiSi HEA coating was deposited using powder milled for 10 h, which can be used as an ideal feedstock for APS. The surface morphology, microstructure, microhardness, and wear behavior of the coating at room temperature were investigated. The results showed that as the milling time increased, the particle size first increased, and then decreased. At the milling time of 10 h, simple body-centered cubic (BCC) and face-centered cubic (FCC) solid solution phases were formed. After spraying, the lamellar structure inside a single particle disappeared. An ordered BCC phase was detected, and the diffraction peaks of the Si element also disappeared, which indicates that phase transformation occurred during plasma spraying. A transmission electron microscopy analysis showed that nanometer crystalline grains with a grain size of about 30 nm existed in the APS coating. For the coating, an average microhardness of 612 ± 41 HV was obtained. Adhesive wear, tribo-oxidation wear, and slight abrasion wear took place during the wear test. The coating showed good wear resistance, with a volume wear rate of 0.38 ± 0.08 × 10 -4 mm³·N -1 ·m -1 , which makes it a promising coating for use in abrasive environments.

  4. Microstructure and wear resistance of laser cladded composite coatings prepared from pre-alloyed WC-NiCrMo powder with different laser spots

    Science.gov (United States)

    Yao, Jianhua; Zhang, Jie; Wu, Guolong; Wang, Liang; Zhang, Qunli; Liu, Rong

    2018-05-01

    The distribution of WC particles in laser cladded composite coatings can significantly affect the wear resistance of the coatings under aggressive environments. In this study, pre-alloyed WC-NiCrMo powder is deposited on SS316L via laser cladding with circular spot and wide-band spot, respectively. The microstructure and WC distribution of the coatings are investigated with optical microscope (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). The wear behavior of the coatings is investigated under dry sliding-wear test. The experimental results show that the partially dissolved WC particles are uniformly distributed in both coatings produced with circular spot and wide-band spot, respectively, and the microstructures consist of WC and M23C6 carbides and γ-(Ni, Fe) solid solution matrix. However, due to Fe dilution, the two coatings have different microstructural characteristics, resulting in different hardness and wear resistance. The wide-band spot laser prepared coating shows better performance than the circular spot laser prepared coating.

  5. Application of the whole powder pattern decomposition procedure in the residual stress analysis of layers and coatings

    International Nuclear Information System (INIS)

    Schoderböck, Peter; Brechbühl, Jens

    2015-01-01

    The X-ray investigation of stress states in materials, based on the determination of elastic lattice strains which are converted to stresses by means of theory of elasticity, is a necessity in quality control of thin layers and coatings for optimizing manufacturing steps and process parameters. This work introduces the evaluation of residual stress from complex and overlapping diffraction patterns using a whole-powder pattern decomposition procedure defining a 2θ-offset caused by residual stresses. Furthermore corrections for sample displacement and refraction are directly implemented in the calculation procedure. The correlation matrices of the least square fitting routines have been analyzed for parameter interactions and obvious interdependencies have been decoupled by the introduction of an internal standard within the diffraction experiment. This decomposition based evaluation has been developed on tungsten as a model material system and its efficiency was demonstrated by X-ray diffraction analysis of a solid oxide fuel cell multilayer system. The results are compared with those obtained by the classical sin 2 Ψ-method. - Highlights: • Analysis of complex multiphase diffraction patterns with respect to residual stress • Stress-gradient determination with in situ correction of displacement and refraction • Consideration of the elastic anisotropy within the refinement

  6. Properties of polyester based powder coating containing Cloisite®30B modified with silane 3-aminopropyltriethoxysilane; Propriedades da tinta em po base poliester contendo Cloisite®30B modificada com 3-aminopropiltrietoxisilano

    Energy Technology Data Exchange (ETDEWEB)

    Bertuoli, P.T.; Frizzo, V.P.; Zattera, A.J., E-mail: paulabertuoli@hotmail.com [Universidade de Caxias do Sul (UCS), RS (Brazil). Programa de Pos-Graduacao em Engenharia de Processos e Tecnologias; Scienza, L.C. [Universidade Federal do Rio Grande do Sul (UFRGS), RS (Brazil). Departamento de Materiais

    2014-07-01

    The incorporation of clay into a polymer matrix results in nanocomposites with mechanical strength, thermal and barrier properties superior to the free filler matrix. With the aim to obtain a powder coating with better thermal properties than the coating free of filler, the organoclay Cloisite®30B was modified with 3-aminopropyltriethoxysilane (APS) and incorporated to a polyester based powder coating, on proportions of 2 to 8 wt% in the melt state. The powder coatings were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The powder coating containing clay showed no alteration in the basal spacing compared to that basal spacing of the clay. Compared to the powder coating free of the clay, powder coatings containing clay had lower thermal stability due to the presence of the organic modifier. The presence of clay reduced the crosslinking temperature and the incorporation of 2 wt% of the clay caused the increase in the energy released in the crosslinking process. (author)

  7. Low power loss and field-insensitive permeability of Fe-6.5%Si powder cores with manganese oxide-coated particles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Junnan, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Wang, Xian; Xu, Xiaojun; Gong, Rongzhou, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Feng, Zekun [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Yajie; Harris, V. G. [Department of Electrical and Computer Engineering, Center for Microwave Magnetic Materials and Integrated Circuits, Northeastern University, Boston, Massachusetts 02115 (United States)

    2015-05-07

    Fe-6.5%Si alloy powders coated with manganese oxides using an innovative in situ process were investigated. The in-situ coating of the insulating oxides was realized with a KMnO{sub 4} solution by a chemical process. The insulating manganese oxides with mixed valance state were verified by X-ray photoelectron spectroscopy analysis. The thickness of the insulating layer on alloy particles was determined to be in a range of 20–210 nm, depending upon the KMnO{sub 4} concentration. The powder core loss and the change in permeability under a DC-bias field were measured at frequencies ranging from 50 to 100 kHz. The experiments indicated that the Fe-6.5%Si powder cores with a 210 nm-thick manganese oxide layer not only showed a low core loss of 459 mW/cm{sup 3} at 100 kHz but also showed a small reduction in permeability (μ(H)/μ(0) = 85% for μ = 42) at a DC-bias field of 80 Oe. This work has defined a novel pathway to realizing low core loss and field-insensitive permeability for Fe-Si powder cores.

  8. Low-temperature densification and excellent thermal properties of W–Cu thermal-management composites prepared from copper-coated tungsten powders

    International Nuclear Information System (INIS)

    Zhang, Lianmeng; Chen, Wenshu; Luo, Guoqiang; Chen, Pingan; Shen, Qiang; Wang, Chuanbin

    2014-01-01

    Highlights: • High-density (98.4%) W–20 wt.%Cu composites were low-temperature fabricated. • A highly pure Cu network and a homogenous microstructure formed in the composites. • The interfaces between W and Cu are well bonded with no spaces. • The composites have excellent thermal properties. -- Abstract: High-density W–20 wt.%Cu composites containing a Cu-network structure and exhibiting good thermal properties were fabricated by low-temperature hot-press sintering from high-purity copper-coated tungsten powders. The relative density of W–20 wt.%Cu composites sintered at 950 °C–100 MPa–2 h was 98.4%. The low-temperature densification of W–Cu composites occurs because the sintering mode of the coated particles involves only sintering of Cu to Cu, rather than both Cu to W and Cu to Cu, as required for conventional powder particles. The microstructure shows that a network of high-purity Cu extends throughout the composites, and that the W is distributed homogeneously; the interfaces between W and Cu show good contact. The composites have excellent thermal conductivity (239 W/(m K)) and a relatively low coefficient of thermal expansion (7.4 × 10 −6 /K), giving them some of the best properties reported to date for thermal-management materials. The excellent performance is mainly because of their structure, which arises from the characteristics of the high-purity copper-coated tungsten powders

  9. An assessment of thermal spray coating technologies for high temperature corrosion protection

    International Nuclear Information System (INIS)

    Heath, G.R.; Heimgartner, P.; Gustafsson, S.; Irons, G.; Miller, R.

    1997-01-01

    The use of thermally sprayed coatings in combating high temperature corrosion continues to grow in the major industries of chemical, waste incineration, power generation and pulp and paper. This has been driven partially by the development of corrosion resistant alloys, improved knowledge and quality in the thermal spray industry and continued innovation in thermal spray equipment. There exists today an extensive range of thermal spray process options, often with the same alloy solution. In demanding corrosion applications it is not sufficient to just specify alloy and coating method. For the production of reliable coatings the whole coating production envelope needs to be considered, including alloy selection, spray parameters, surface preparation, base metal properties, heat input etc. Combustion, arc-wire, plasma, HVOF and spray+fuse techniques are reviewed and compared in terms of their strengths and limitations to provide cost-effective solutions for high temperature corrosion protection. Arc wire spraying, HP/HVOF and spray+fuse are emerging as the most promising techniques to optimise both coating properties and economic/practical aspects. (orig.)

  10. C18-coated stir bar sorptive extraction combined with high performance liquid chromatography-electrospray tandem mass spectrometry for the analysis of sulfonamides in milk and milk powder.

    Science.gov (United States)

    Yu, Chunhe; Hu, Bin

    2012-02-15

    A simple, rapid, sensitive, inexpensive and less sample consuming method of C(18)-stir bar sorptive extraction (SBSE)-high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) was proposed for the determination of six sulfonamides in milk and milk powder samples. C(18) silica particles coated stir bar was prepared by adhesion method, and two kinds of adhesive glue, polydimethylsiloxane (PDMS) sol and epoxy glue were tried. It was found that the C(18)-coated stir bar prepared by PDMS sol as adhesive glue is more robust than that prepared by epoxy glue when liquid desorption was employed, in terms of both lifetime and organic solvent tolerance. The preparation of C(18) stir bar was simple with good mechanic strength and the stir bar could be reused for more than 20 times. Granular coating has relatively high specific surface area and is propitious to sorptive extraction based process. Compared to conventional PDMS SBSE coating, C(18) coating shows good affinity to the target polar/weak polar sulfonamides. To achieve optimum SBSE extraction performance, several parameters including extraction and desorption time, ionic strength, sample pH and stirring speed were investigated. The detection limits of the proposed method for six sulfonamides were in the range of 0.9-10.5 μg/L for milk and 2.7-31.5 μg/kg for milk powder. Good linearities were obtained for sulfonamides with the correlation coefficients (R) above 0.9922. Finally, the proposed method was successfully applied to the determination of sulfonamides in milk and milk powder samples and satisfied recoveries of spiked target compounds in real samples were obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Zn2+ in-situ substitution behavior during the formation of BaTiO3 coatings from plasma-sprayed powders collected in liquid nitrogen

    Science.gov (United States)

    Liu, Zhe; Xing, Zhiguo; Wang, Haidou; Xue, Zifan; Chen, Shuying; Cui, Xiufang; Jin, Guo

    2018-04-01

    The dielectric performance of BaTiO3 ceramic coatings is enhanced significantly by the addition of ZnO. In this study, the maximum relative permittivity value (εr ≈ 923) was measured in BaTiO3 coatings with ZnO added at 6 wt%. The Curie temperature (Tc) was in the range of 111 °C-121 °C for all of the ZnO-modified BaTiO3 coatings. Tc shifted to low temperatures as the ZnO content increased. Detailed analyses were performed to determine the phase composition and optical band gaps of powders collected in liquid nitrogen, which showed that the Zn2+ ions were incorporated into the BaTiO3 lattice where they substituted into the Ti4+ sites, and the composite powders (BaTiO3 + 6 wt% ZnO) tolerated high temperatures in the plasma beam. In addition, some residual Zn accumulated in the grain boundary in the form of ZnO. X-ray diffraction and Raman spectroscopy showed that the substitution led to changes in the compositional and structural properties. The red shift in the optical band gap of BaTiO3 indicated that the ZnTi'' defects caused by the dopants acted as carriers in the doped BaTiO3 coatings.

  12. In Situ Fabrication of AlN Coating by Reactive Plasma Spraying of Al/AlN Powder

    Directory of Open Access Journals (Sweden)

    Mohammed Shahien

    2011-10-01

    Full Text Available Reactive plasma spraying is a promising technology for the in situ formation of aluminum nitride (AlN coatings. Recently, it became possible to fabricate cubic-AlN-(c-AlN based coatings through reactive plasma spraying of Al powder in an ambient atmosphere. However, it was difficult to fabricate a coating with high AlN content and suitable thickness due to the coalescence of the Al particles. In this study, the influence of using AlN additive (h-AlN to increase the AlN content of the coating and improve the reaction process was investigated. The simple mixing of Al and AlN powders was not suitable for fabricating AlN coatings through reactive plasma spraying. However, it was possible to prepare a homogenously mixed, agglomerated and dispersed Al/AlN mixture (which enabled in-flight interaction between the powder and the surrounding plasma by wet-mixing in a planetary mill. Increasing the AlN content in the mixture prevented coalescence and increased the nitride content gradually. Using 30 to 40 wt% AlN was sufficient to fabricate a thick (more than 200 µm AlN coating with high hardness (approximately 1000 Hv. The AlN additive prevented the coalescence of Al metal and enhanced post-deposition nitriding through N2 plasma irradiation by allowing the nitriding species in the plasma to impinge on a larger Al surface area. Using AlN as a feedstock additive was found to be a suitable method for fabricating AlN coatings by reactive plasma spraying. Moreover, the fabricated coatings consist of hexagonal (h-AlN, c-AlN (rock-salt and zinc-blend phases and certain oxides: aluminum oxynitride (Al5O6N, cubic sphalerite Al23O27N5 (ALON and Al2O3. The zinc-blend c-AlN and ALON phases were attributed to the transformation of the h-AlN feedstock during the reactive plasma spraying. Thus, the zinc-blend c

  13. Superfine powdered activated carbon (S-PAC) coatings on microfiltration membranes: Effects of milling time on contaminant removal and flux.

    Science.gov (United States)

    Amaral, Pauline; Partlan, Erin; Li, Mengfei; Lapolli, Flavio; Mefford, O Thompson; Karanfil, Tanju; Ladner, David A

    2016-09-01

    In microfiltration processes for drinking water treatment, one method of removing trace contaminants is to add powdered activated carbon (PAC). Recently, a version of PAC called superfine PAC (S-PAC) has been under development. S-PAC has a smaller particle size and thus faster adsorption kinetics than conventionally sized PAC. Membrane coating performance of various S-PAC samples was evaluated by measuring adsorption of atrazine, a model micropollutant. S-PACs were created in-house from PACs of three different materials: coal, wood, and coconut shell. Milling time was varied to produce S-PACs pulverized with different amounts of energy. These had different particles sizes, but other properties (e.g. oxygen content), also differed. In pure water the coal based S-PACs showed superior atrazine adsorption; all milled carbons had over 90% removal while the PAC had only 45% removal. With addition of calcium and/or NOM, removal rates decreased, but milled carbons still removed more atrazine than PAC. Oxygen content and specific external surface area (both of which increased with longer milling times) were the most significant predictors of atrazine removal. S-PAC coatings resulted in loss of filtration flux compared to an uncoated membrane and smaller particles caused more flux decline than larger particles; however, the data suggest that NOM fouling is still more of a concern than S-PAC fouling. The addition of calcium improved the flux, especially for the longer-milled carbons. Overall the data show that when milling S-PAC with different levels of energy there is a tradeoff: smaller particles adsorb contaminants better, but cause greater flux decline. Fortunately, an acceptable balance may be possible; for example, in these experiments the coal-based S-PAC after 30 min of milling achieved a fairly high atrazine removal (overall 80%) with a fairly low flux reduction (under 30%) even in the presence of NOM. This suggests that relatively short duration (low energy

  14. A new titanium based alloy Ti-27Nb-13Zr produced by powder metallurgy with biomimetic coating for use as a biomaterial.

    Science.gov (United States)

    Mendes, Marcio W D; Ágreda, Carola G; Bressiani, Ana H A; Bressiani, José C

    2016-06-01

    Titanium alloys are widely used in biomedical applications due to their excellent properties such as high strength, good corrosion resistance and biocompatibility. Titanium alloys with alloying elements such as Nb and Zr are biocompatible and have Young's modulus close to that of human bone. To increase the bioactivity of titanium alloy surfaces is used chemical treatment with NaOH followed by immersion in simulated body fluid (SBF). The purpose of this study was to produce the alloy Ti-27Nb-13Zr with low Young's modulus by powder metallurgy using powders produced by the HDH process. The formation of biomimetic coatings on samples immersed in SBF for 3, 7, 11 and 15 days was evaluated. Characterization of the coating was performed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and scanning electron microscope. The microstructure and composition of the alloy were determined using SEM and XRD, while the mechanical properties were evaluated by determining the elastic modulus and the Vickers microhardness. The sintered alloys were composed of α and β phases, equiaxed grains and with density around 97.8% of its theoretical density. The Vickers microhardness and elasticity modulus of the alloy were determined and their values indicate that this alloy can be used as a biomaterial. Analysis of the coating revealed the presence of calcium phosphate layers on samples immersed for >3 days in the SBF solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Influence of steam-based pre-treatment using acidic chemistries on the adhesion performance of powder coated aluminium alloy AA6060

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Nikogeorgos, Nikolaos; Jellesen, Morten Stendahl

    2017-01-01

    In this study, the adhesion of a commercially applied powder coating on a steam treated AA6060 surface withpure steam and steam with citric and phosphoric acid chemistries has been investigated. Contact angle,roughness, and nanoscale pull off forces were determined as a function of the steam trea...... with citric and phosphoric acid resulted in poor penetration of th eadhesive over the intermetallic particles, and the interface showed mixed (cohesive/adhesive) fracture during interface indentation, while the pure steam treated surface showed dominant cohesive fracture....

  16. Superhydrophobic powder additives to enhance chemical agent resistant coating systems for military equipment for the U.S. Marine Corps (USMC) Corrosion Prevention and Control (CPAC) Program

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Haynes, James A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    The primary goal of the CPAC program at ORNL was to explore the feasibility of introducing various silica-based superhydrophobic (SH) powder additives as a way to improve the corrosion resistance of US Department of Defense (DOD) military-grade chemical agent resistant coating (CARC) systems. ORNL had previously developed and patented several SH technologies of interest to the USMC, and one of the objectives of this program was to identify methods to incorporate these technologies into the USMC’s corrosion-resistance strategy. This report discusses findings of the CPAC and their application.

  17. Powder addition assessment of manganese residue ceramic matrix coating; Avaliacao da adicao do po de residuo de manganes em matriz ceramica para revestimento

    Energy Technology Data Exchange (ETDEWEB)

    Conceicao, A.C.R. da; Santos, O.C.; Leao, M.A., E-mail: arangel-ma@hotmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia (IFBA), BA (Brazil)

    2016-07-01

    The use of recycled materials in the composition of new products follows the production's worldwide trending, meeting new technological requirements and environmental concerns. This work aims to utilize the residue of manganese dust on ceramic mass for the production of ceramic coating. The raw materials were characterized by both x-ray fluorescence and diffraction. The powder residue added to clay in the percentage of 0%, 5%, 10% and 15% (measured in weight) was compressed by a uniaxial pressing of 30MPa and the sintering temperatures were 900°, 1000° and 1100°. The samples were analysed in relation to flexural strength, bulk density, water absorption and linear shrinkage. The microstructural variation was also analysed by x-ray diffraction and electron microscopy. The results showed that there is a viability for the production of porcelain ceramic coating (A3 and A4 formulations) and stoneware (A2 formulation) according to the specification of technical standards. author)

  18. Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

    Energy Technology Data Exchange (ETDEWEB)

    Jakupi, P. [Western University, Dept. of Chemistry, London Ontario, N6A 3K7 (Canada); Keech, P.G. [Nuclear Waste Management Organization, 22 St. Clair Ave. E., Toronto Ontario, M4T 2S3 (Canada); Barker, I. [Western University, Dept. of Earth Sciences, London Ontario, N6A 3K7 (Canada); Ramamurthy, S.; Jacklin, R.L. [Western University, Surface Science Western, 999 Collip Circle, LL31 (Lower), London, Ontario, N6G OJ3 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.ca [Western University, Surface Science Western, 999 Collip Circle, LL31 (Lower), London, Ontario, N6G OJ3 (Canada); Moser, D.E. [Western University, Dept. of Earth Sciences, London Ontario, N6A 3K7 (Canada)

    2015-11-15

    Copper coated steel containers are being developed for the disposal of high level nuclear waste using processes such as cold spray and electrodeposition. Electron Back-Scatter Diffraction has been used to determine the microstructural properties and the quality of the steel-copper coating interface. The influence of the nature of the cold-spray carrier gas as well as its temperature and pressure (velocity) on the coating's plastic strain and recrystallization behaviour have been investigated, and one commercially-produced electrodeposited coating characterized. The quality of the coatings was assessed using the coincident site lattice model to analyse the properties of the grain boundaries. For cold spray coatings the grain size and number of coincident site lattice grain boundaries increased, and plastic strain decreased, with carrier gas velocity. In all cases annealing improved the quality of the coatings by increasing texture and coincidence site-lattices, but also increased the number of physical voids, especially when a low temperature cold spray carrier gas was used. Comparatively, the average grain size and number of coincident site-lattices was considerably larger for the strongly textured electrodeposited coating. Tensile testing showed the electrodeposited coating was much more strongly adherent to the steel substrate.

  19. Mathematical modeling of the gas and powder flow in the (HVOF) systems to optimize their coatings quality

    Science.gov (United States)

    Tawfik, Hazem H.

    1996-01-01

    Thermally sprayed coatings have been extensively used to enhance materials properties and provide surface protection against their working environments in a number of industrial applications. Thermal barrier coatings (TBC) are used to reduce the thermal conductivity of aerospace turbine blades and improve the turbine overall thermal efficiency. TBC allows higher gas operating temperatures and lower blade material temperatures due to the thermal insulation provided by these ceramic coatings. In the automotive industry, coatings are currently applied to a number of moving parts that are subjected to friction and wear inside the engine such as pistons, cylinder liners, valves and crankshafts to enhance their wear resistance and prolong their useful operation and lifetime.

  20. Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

    Science.gov (United States)

    Jakupi, P.; Keech, P. G.; Barker, I.; Ramamurthy, S.; Jacklin, R. L.; Shoesmith, D. W.; Moser, D. E.

    2015-11-01

    Copper coated steel containers are being developed for the disposal of high level nuclear waste using processes such as cold spray and electrodeposition. Electron Back-Scatter Diffraction has been used to determine the microstructural properties and the quality of the steel-copper coating interface. The influence of the nature of the cold-spray carrier gas as well as its temperature and pressure (velocity) on the coating's plastic strain and recrystallization behaviour have been investigated, and one commercially-produced electrodeposited coating characterized. The quality of the coatings was assessed using the coincident site lattice model to analyse the properties of the grain boundaries. For cold spray coatings the grain size and number of coincident site lattice grain boundaries increased, and plastic strain decreased, with carrier gas velocity. In all cases annealing improved the quality of the coatings by increasing texture and coincidence site-lattices, but also increased the number of physical voids, especially when a low temperature cold spray carrier gas was used. Comparatively, the average grain size and number of coincident site-lattices was considerably larger for the strongly textured electrodeposited coating. Tensile testing showed the electrodeposited coating was much more strongly adherent to the steel substrate.

  1. Application of Pre-coated Microfiltration Ceramic Membrane with Powdered Activated Carbon for Natural Organic Matter Removal from Secondary Wastewater Effluent

    KAUST Repository

    Kurniasari, Novita

    2012-12-01

    Ceramic membranes offer more advantageous performances than conventional polymeric membranes. However, membrane fouling caused by Natural Organic Matters (NOM) contained in the feed water is still become a major problem for operational efficiency. A new method of ceramic membrane pre-coating with Powdered Activated Carbon (PAC), which allows extremely contact time for adsorbing aquatic contaminants, has been studied as a pre-treatment prior to ceramic microfiltration membrane. This bench scale study evaluated five different types of PAC (SA Super, G 60, KCU 6, KCU 8 and KCU 12,). The results showed that KCU 6 with larger pore size was performed better compared to other PAC when pre-coated on membrane surface. PAC pre-coating on the ceramic membrane with KCU 6 was significantly enhance NOM removal, reduced membrane fouling and improved membrane performance. Increase of total membrane resistance was suppressed to 96%. The removal of NOM components up to 92%, 58% and 56% for biopolymers, humic substances and building blocks, respectively was achieved at pre-coating dose of 30 mg/l. Adsorption was found to be the major removal mechanism of NOM. Results obtained showed that biopolymers removal are potentially correlated with enhanced membrane performance.

  2. The Level of SGOT and SGPT after The Administration of Powdered Colorant Pigment Isolated from Kesumba Keling’s (Bixa Orellana Seed Coats An experimental study in Balb/C Mice

    Directory of Open Access Journals (Sweden)

    Suparmi Suparmi

    2011-06-01

    Design and Methods: The research is an experimental research with Factorial Design with 2 factors. Food Colorant Powder was made from bixin, norbixin, and crude extract pigment isolated from B. orellana seed coat’s. A total of 60 male mice were divided into 10 treatment groups. Powdered colorant solution at the concentration of 0% (control, 1%, 5%, and 10% were orally administered using gavage as much as 1 ml a day for 30 days. Results: Kruskal Wallis test results shows a not significant difference SGOT and SGPT level among the groups (p > 0.05, thus consumption of colorant powder of bixin, norbixin, and the crude extract with various concentrations did not affect the SGOT and SGPT. Conclusion: Colorant powder isolated from B. orellana seed coat’s has been shown to have no effect on the liver function, so it is safe as food colorant (Sains Medika, 3(1:69-77.

  3. A new titanium based alloy Ti–27Nb–13Zr produced by powder metallurgy with biomimetic coating for use as a biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Marcio W.D., E-mail: mwdmendes@ipen.com; Ágreda, Carola G.; Bressiani, Ana H.A.; Bressiani, José C.

    2016-06-01

    Titanium alloys are widely used in biomedical applications due to their excellent properties such as high strength, good corrosion resistance and biocompatibility. Titanium alloys with alloying elements such as Nb and Zr are biocompatible and have Young's modulus close to that of human bone. To increase the bioactivity of titanium alloy surfaces is used chemical treatment with NaOH followed by immersion in simulated body fluid (SBF). The purpose of this study was to produce the alloy Ti–27Nb–13Zr with low Young's modulus by powder metallurgy using powders produced by the HDH process. The formation of biomimetic coatings on samples immersed in SBF for 3, 7, 11 and 15 days was evaluated. Characterization of the coating was performed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and scanning electron microscope. The microstructure and composition of the alloy were determined using SEM and XRD, while the mechanical properties were evaluated by determining the elastic modulus and the Vickers microhardness. The sintered alloys were composed of α and β phases, equiaxed grains and with density around 97.8% of its theoretical density. The Vickers microhardness and elasticity modulus of the alloy were determined and their values indicate that this alloy can be used as a biomaterial. Analysis of the coating revealed the presence of calcium phosphate layers on samples immersed for > 3 days in the SBF solution. - Highlights: • The alloy is classified as α + β and the milling time influences the formation of these phases. • Dissolution of Nb is related to the mechanical properties of the alloy. • It's possible to form apatite on all samples immersed in SBF from 3 days. • The alloy can be used in orthopedic applications or in dental applications.

  4. Eddy-current testing of fatigue degradation upon contact fatigue loading of gas powder laser clad NiCrBSi-Cr3C2 composite coating

    Science.gov (United States)

    Savrai, R. A.; Makarov, A. V.; Gorkunov, E. S.; Soboleva, N. N.; Kogan, L. Kh.; Malygina, I. Yu.; Osintseva, A. L.; Davydova, N. A.

    2017-12-01

    The possibilities of the eddy-current method for testing the fatigue degradation under contact loading of gas powder laser clad NiCrBSi-Cr3C2 composite coating with 15 wt.% of Cr3C2 additive have been investigated. It is shown that the eddy-current testing of the fatigue degradation under contact loading of the NiCrBSi-15%Cr3C2 composite coating can be performed at high excitation frequencies 72-120 kHz of the eddy-current transducer. At that, the dependences of the eddy-current instrument readings on the number of loading cycles have both downward and upward branches, with the boundary between the branches being 3×105 cycles in the given loading conditions. This is caused, on the one hand, by cracking, and, on the other hand, by cohesive spalling and compaction of the composite coating, which affect oppositely the material resistivity and, correspondingly, the eddy-current instrument readings. The downward branch can be used to monitor the processes of crack formation and growth, the upward branch - to monitor the degree of cohesive spalling, while taking into account in the testing methodology an ambiguous character of the dependences of the eddy-current instrument readings on the number of loading cycles.

  5. Mathematical modelling of powder material motion and transportation in high-temperature flow core during plasma coatings application

    Science.gov (United States)

    Bogdanovich, V. I.; Giorbelidze, M. G.

    2018-03-01

    A problem of mathematical modelling of powder material motion and transportation in gas thermal flow core has been addressed. Undertaken studies indicate significant impact on dynamics of motion of sprayed particles of phenomenological law for drag coefficient and accounting momentum loss of a plasma jet upon acceleration of these particles and their diameter. It is determined that at great dispersion of spraying particles, they reach detail surface at different velocity and significant particles separation takes place at spraying spot. According to the results of mathematical modelling, requirements for admissible dispersion of diameters of particles used for spraying have been formulated. Research has also allowed reducing separation of particles at the spraying spot due to the selection of the method of powder feed to the anode channel of the plasma torch.

  6. Enhanced oral bioavailability of novel mucoadhesive pellets containing valsartan prepared by a dry powder-coating technique

    DEFF Research Database (Denmark)

    Cao, Qing-Ri; Liu, Yan; Xu, Wei-Juan

    2012-01-01

    The aim of this study was to develop novel mucoadhesive pellets containing valsartan (VAL) with enhanced oral bioavailability. Two types of VAL loaded core pellets were prepared by an extrusion/spheronization method, and further dry-coated with a mixture of hydroxypropylmethylcellulose (HPMC...

  7. Chip-based molecularly imprinted monolithic capillary array columns coated GO/SiO2 for selective extraction and sensitive determination of rhodamine B in chili powder.

    Science.gov (United States)

    Zhai, Haiyun; Huang, Lu; Chen, Zuanguang; Su, Zihao; Yuan, Kaisong; Liang, Guohuan; Pan, Yufang

    2017-01-01

    A novel solid-phase extraction chip embedded with array columns of molecularly imprinted polymer-coated silanized graphene oxide (GO/SiO2-MISPE) was established to detect trace rhodamine B (RB) in chili powder. GO/SiO2-MISPE monolithic columns for RB detection were prepared by optimizing the supporting substrate, template, and polymerizing monomer under mild water bath conditions. Adsorption capacity and specificity, which are critical properties for the application of the GO/SiO2-MISPE monolithic column, were investigated. GO/SiO2-MIP was examined by scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy. The recovery and the intraday and interday relative standard deviations for RB ranged from 83.7% to 88.4% and 2.5% to 4.0% and the enrichment factors were higher than 110-fold. The chip-based array columns effectively eliminated impurities in chili powder, indicating that the chip-based GO/SiO2-MISPE method was reliable for RB detection in food samples using high-performance liquid chromatography. Accordingly, this method has direct applications for monitoring potentially harmful dyes in processed food. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Synthesis of Y{sub 2}O{sub 3}:(Li,Eu) films using phosphor powders coated with SiO{sub 2} nano particles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In-Gyu; Park, Sangmoon [Center for Green Fusion Technology and Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Kang, Seong-Gu [Department of Chemical Engineering, Hoseo University, Chungnam 336-795 (Korea, Republic of); Park, Jung-Chul, E-mail: parkjc@silla.ac.k [Center for Green Fusion Technology and Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of)

    2010-08-15

    Y{sub 1.9-x}Li{sub 0.1}Eu{sub x}O{sub 3} (x=0.02, 0.05, 0.08, and 0.12) films were fabricated by spin-coating method. A colloidal silica suspension with Y{sub 1.9-x}Li{sub 0.1}Eu{sub x}O{sub 3} phosphor powder was exploited to obtain the highly stable and effective luminescent films onto the glass substrate. After heating as-prepared Y{sub 1.9-x}Li{sub 0.1}Eu{sub x}O{sub 3} films at 700 {sup o}C for 1 h, the phosphor films exhibit a high luminescent brightness as well as a strong adhesiveness on the glass substrate. The emission spectra of spin-coated and pulse-laser deposited Y{sub 1.82}Li{sub 0.1}Eu{sub 0.08}O{sub 3} films were compared. The cathodoluminescence of the phosphor films was carried out at the anode voltage 1 kV.

  9. Synthesis of silicon carbide coating on diamond by microwave heating of diamond and silicon powder: A heteroepitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Leparoux, S. [Empa, Department of Materials Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)], E-mail: susanne.leparoux@empa.ch; Diot, C. [Consultant, allee de Mozart 10, F-92300 Chatillon (France); Dubach, A. [Empa, Department of Materials Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Vaucher, S. [Empa, Department of Materials Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)

    2007-10-15

    When a powder mixture of diamond and silicon is heated by microwaves, heteroepitaxial growth of SiC is observed on the (1 1 1) as well as on the (1 0 0) faces of the diamond. The SiC over-layer was characterized by X-ray diffraction and scanning electron microscopy. High-resolution scanning electron microscopy shows the presence of triangular silicon carbide on the (1 1 1) faces of diamond while prismatic crystals are found on the (1 0 0) faces. The crystal growth seems to be favored in the plane parallel to the face (1 1 1)

  10. Synthesis of silicon carbide coating on diamond by microwave heating of diamond and silicon powder: A heteroepitaxial growth

    International Nuclear Information System (INIS)

    Leparoux, S.; Diot, C.; Dubach, A.; Vaucher, S.

    2007-01-01

    When a powder mixture of diamond and silicon is heated by microwaves, heteroepitaxial growth of SiC is observed on the (1 1 1) as well as on the (1 0 0) faces of the diamond. The SiC over-layer was characterized by X-ray diffraction and scanning electron microscopy. High-resolution scanning electron microscopy shows the presence of triangular silicon carbide on the (1 1 1) faces of diamond while prismatic crystals are found on the (1 0 0) faces. The crystal growth seems to be favored in the plane parallel to the face (1 1 1)

  11. Application of laser in powder metallurgy

    International Nuclear Information System (INIS)

    Tolochko, N.K.

    1995-01-01

    Modern status of works in the field of laser application in powder metallurgy (powders preparation, sintering, coatings formation, powder materials processing) is considered. The attention is paid to the new promising direction in powder products shape-formation technology - laser layer-by-layer selective powders sintering and bulk sintering of packaged layered profiles produced by laser cutting of powder-based sheet blanks. 67 refs

  12. Uticaj brzine depozicije praha na mehaničke karakteristike i strukturu APS-NiCr/Al prevlake / Effect of the powder deposition rate on the mechanical properties and the structure of the APS-NiCr/Al coating

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2010-10-01

    Full Text Available U radu su prikazani rezultati ispitivanja atmosferskih plazma-sprej prevlaka APS-NiCr/Al. Kompozitni prah NiCr/Al koji se sastoji od NiCr čestica obloženih finim česticama Al u procesu depozicije omogućuje egzotermnu reakciju. Reakcija ovih metala dovodi do formiranja samovezujućih NiCrAl prevlaka koje poseduju jedinstvene kombinacije osobina. Radi dobijanja najboljih strukturnih i mehaničkih karakteristika izvršena je optimizacija parametara depozicije. U ovom istraživanju urađene su tri grupe uzoraka prevlake NiCrAl sa različitim brzinama depozicije praha da bi se dobili depoziti velike čvrstoće i žilavosti. Kod prve grupe uzoraka brzina depozicije praha bila je 50 g/min, kod druge 40 g/min, a kod treće 30 g/min. Procena osobina depozita rađena je ispitivanjem mikrotvrdoće metodom HV0.3 i čvrstoće spoja ispitivanjem na zatezanje. Metalografska procena strukture rađena je tehnikom svetlosne mikroskopije. Verifikovane prevlake primenjene su za zaštitu i revitalizaciju delova turbomlaznih motora izloženih oksidaciji na povišenim temperaturama. / The paper presents the results of the examination of atmospheric plasma spraying of APS-NiCr/Al coatings. Composite NiCr/Al powders, composed of NiCr particles coated with fine Al particles, enable an exothermic reaction during the deposition process. The exothermic reaction of these metals results in the formation of selfbonding NiCrAl coatings with a unique combination of properties. For the purpose of obtaining excellent structural and mechanical properties, the deposition parameters were optimized. In this study, three groups of NiCrAl coating samples with different powder deposition rate were made to get deposits of greater strength and toughness. In the first group of samples, the deposition rate was 50g/min, in the second group the powder deposition rate was 40 g/ min. while in the third group it was 30 g/min. The assessment of the properties of deposits was made by the HV0

  13. Matrix-compatible sorbent coatings based on structurally-tuned polymeric ionic liquids for the determination of acrylamide in brewed coffee and coffee powder using solid-phase microextraction.

    Science.gov (United States)

    Cagliero, Cecilia; Nan, He; Bicchi, Carlo; Anderson, Jared L

    2016-08-12

    Nine crosslinked polymeric ionic liquid (PIL)-based SPME sorbent coatings were designed and screened in this study for the trace level determination of acrylamide in brewed coffee and coffee powder using gas chromatography-mass spectrometry (GC-MS). The structure of the ionic liquid (IL) monomer was tailored by introducing different functional groups to the cation and the nature of the IL crosslinker was designed by altering both the structure of the cation as well as counteranions. The extraction efficiency of the new PIL coatings towards acrylamide was investigated and compared to a previously reported PIL sorbent coating. All PIL fibers exhibited excellent analytical precision and linearity. The PIL fiber coating consisting of 50% 1,12-di(3-vinylbenzylbenzimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide as IL crosslinker in 1-vinyl-3-(10-hydroxydecyl)imidazolium bis[(trifluoromethyl)sulfonyl]imide IL monomer resulted in a limit of quantitation of 0.5μgL(-1) with in-solution SPME sampling. The hydroxyl moiety appended to the IL cation was observed to significantly increase the sensitivity of the PIL coating toward acrylamide. The quantitation of acrylamide in brewed coffee and coffee powder was performed using the different PIL-based fibers by the method of standard addition after a quenching reaction using ninhydrin to inhibit the formation of interfering acrylamide in the GC inlet, mainly by asparagine thermal degradation. Excellent repeatability with relative standard deviations below 10% were obtained on the real coffee samples and the structure of the coatings appeared intact by scanning electron microscopy after coffee sampling proving the matrix-compatibility of the PIL sorbent coatings. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. C, N co-doped TiO_2/TiC_0_._7N_0_._3 composite coatings prepared from TiC_0_._7N_0_._3 powder using ball milling followed by oxidation

    International Nuclear Information System (INIS)

    Hao, Liang; Wang, Zhenwei; Zheng, Yaoqing; Li, Qianqian; Guan, Sujun; Zhao, Qian; Cheng, Lijun; Lu, Yun; Liu, Jizi

    2017-01-01

    Highlights: • TiO_2/TiC_0_._7N_0_._3 coatings were prepared by ball milling followed by oxidation. • In situ co-doping of C and N with simultaneous TiO_2 formation was observed. • Improved photocatalytic activity under UV/visible light was noticed. • Synergism in co-doping and heterojunction formation promoted carrier separation. - Abstract: Ball milling followed by heat oxidation was used to prepared C, N co-doped TiO_2 coatings on the surfaces of Al_2O_3 balls from TiC_0_._7N_0_._3 powder. The as-prepared coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrophotometer (UV–vis). The results show that continuous TiC_0_._7N_0_._3 coatings were formed after ball milling. C, N co-doped TiO_2/TiC_0_._7N_0_._3 composite coatings were prepared after the direct oxidization of TiC_0_._7N_0_._3 coatings in the atmosphere. However, TiO_2 was hardly formed in the surface layer of TiC_0_._7N_0_._3 coatings within a depth less than 10 nm during the heat oxidation of TiC_0_._7N_0_._3 coatings in carbon powder. Meanwhile, the photocatalytic activity evaluation of these coatings was conducted under the irradiation of UV and visible light. All the coatings showed photocatalytic activity in the degradation of MB no matter under the irradiation of UV or visible light. The C, N co-doped TiO_2/TiC_0_._7N_0_._3 composite coatings showed the most excellent performance. The enhancement under visible light irradiation should attribute to the co-doping of carbon and nitrogen, which enhances the absorption of visible light. The improvement of photocatalytic activity under UV irradiation should attribute to the synergistic effect of C, N co-doping, the formation of rutile-anatase mixed phases and the TiO_2/TiC_0_._7N_0_._3 composite microstructure.

  15. Electrochemical Characteristics of a Diamond-Like-Carbon-Coated LiV3O8 Cathode When Used in a Li-Metal Battery with a Li-Powder Anode

    Science.gov (United States)

    Lee, Jae Ha; Lee, Jun Kyu; Yoon, Woo Young

    2013-10-01

    A diamond-like-carbon (DLC)-coated LiV3O8 cathode was synthesized for use in a rechargeable 2032-coin-type cell with a Li-powder electrode (LPE) as the anode. The LPE anode was produced using the droplet emulsion technique and was compacted by pressing. The initial discharge capacity of the LPE/DLC-coated LiV3O8 (LVO) cell was 238 mAh g-1 at a C-rate of 0.5, while that of a LPE/bare-LVO cell was 236 mAh g-1. After 50 cycles, the capacity retention rate of the DLC-coated-electrode-containing cell (92%) was higher than that of the uncoated-electrode-containing cell (77%). Results of electron probe microanalysis and Raman spectroscopy confirmed that the electrode had been coated with DLC. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to determine the sequence of formation of byproducts on the electrode after charging/discharging and to determine its surface composition. The voltage profile and impedance of the DLC-coated-electrode-containing cell were analyzed to determine the electrochemical characteristics of the DLC-coated cathode.

  16. Synthesis and characterization of Yb and Er based monosilicate powders and durability of plasma sprayed Yb2SiO5 coatings on C/C–SiC composites

    International Nuclear Information System (INIS)

    Khan, Zuhair S.; Zou Binglin; Huang Wenzhi; Fan Xizhi; Gu Lijian; Chen Xiaolong; Zeng Shuibing; Wang Chunjie; Cao Xueqiang

    2012-01-01

    Highlights: ► Ultra-pure rare-earth monosilicate powders based on Er and Yb have been fabricated by solid-state reaction. ► Spray-drying treatment results in powders with free flowing characteristics and rounded surface morphologies. ► CTEs are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 . ► Plasma spraying has been used to deposit Yb 2 SiO 5 coatings on C/C–SiC substrate. ► Coatings remain strongly intact with the substrate on thermal cycling between ∼400 °C and 1500 °C in gas burner rig experiment. - Abstract: Rare-earth silicates such as Yb 2 SiO 5 and Er 2 SiO 5 are promising environmental barrier coating materials for ceramic matrix composites. In this work, Yb 2 SiO 5 and Er 2 SiO 5 ceramic powders have been synthesized by solid-state reaction using Yb 2 O 3 , Er 2 O 3 and SiO 2 as starting materials. The fabricated powders were subjected to spray drying treatment for subsequent synthesis of coatings by plasma spraying. The spray drying resulted in well-dispersed and spherical powder particles with good flowability. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry and differential scanning calorimetry (TGA/DSC) and dilatometry were applied to study the microstructural and thermal characteristics of the powders. Ultra-high purity monosilicate powders formed as a result of heating treatments at 1400 °C in a box furnace for 20 h. TG/DSC revealed the genesis temperatures of the silicate formation (low temperature polymorphs) and also showed that the solid-state reactions to form Yb and Er based monosilicates proceeded without any weight-loss in the tested temperature range. The values of coefficients of thermal expansion (CTE) of the fabricated compounds are found to be 7.1 ppm/°C for Yb 2 SiO 5 and 7.5 ppm/°C for Er 2 SiO 5 by dilatometric measurements. Besides these studies, coating formation by plasma spraying of spray-dried Yb 2 SiO 5 powders on the ceramic

  17. Peculiar features of metallurgical processes at plasma-arc spraying of coatings, made of steel wire with powder fillers B4C and B4C+ZrO2

    Directory of Open Access Journals (Sweden)

    Георгій Михайлович Григоренко

    2016-11-01

    Full Text Available The interaction of metallurgical processes occurring in plasma-arc spraying between the steel shell and the carbide fillers of B4C and B4C cored wires with the addition of nanocrystalline ZrO2 powder has been analyzed. Iron-boron compounds alloyed with carbon are formed in ingots as a result of ferritiс coating of wire interacrion with fillers while the ferritic matrix contains boride and carboboride eutectics. Average microhardness of the carboboride compounds and the matrix is high – 17,78; 16,40 and 8,69; 9,95 GPa for the ingots with с B4C and B4C+ZrO2 respectively. The best quality coatings with low porosity (~1%, lamellar structure consisting of ferrite matrix reinforced with dispersed Fe borides, were obtained at a higher heat input (plasmatron current 240-250 A. The average amount of oxides in the coatings makes 15%. 0,5% addition of nanopowder ZrO2 accelerates dispersed iron-boron compounds forming, promotes their uniform distribution in the structure and improves coating microhardness up to 7,0 GPa. Application of the differential thermal analysis method to simulate the interaction processes between the steel shell and the filler during the heating of wire in the shielding gas makes it possible to promote formation of new phases (borides and carboborides of iron and to predict the phase composition of the coatings

  18. In situ synthesis of Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite by vacuum sintering mechanically alloyed TiAl powder coated with CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin (China); Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Nash, Philip [Thermal Processing Technology Center, Illinois Institute of Technology, IL (United States); Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2013-11-25

    Highlights: •Using zwitterionic surfactant to enhance the dispersion of the CNTs on the powder surface. •CNTs as carbon source decreased the formation temperature of Ti{sub 2}AlC. •Al{sub 2}O{sub 3} was generated in situ from the oxygen atoms introduced in the drying procedure. •Nanosized Ti{sub 3}Al was precipitated at 1250 °C and distribute in the TiAl matrix homogeneously. •Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite was synthesized in situ by sintering pre-alloy Ti–Al coated with CNTs. -- Abstract: Bulk Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were in situ synthesized by vacuum sintering mechanically alloyed Ti–50 at.% Al powders coated with carbon nanotubes (CNTs). The pre-alloyed Ti–50 at.% Al powder was obtained by ball milling Ti and Al powders. The multi-walled carbon nanotubes as the carbon resource were covered on the surface of the pre-alloyed powders by immersing them into a water solution containing the CNTs. A zwitterionic surfactant was used to enhance the dispersion of the CNTs on the powder surface. The samples were cold pressed and sintered in vacuum at temperatures from 950 to 1250 °C, respectively. The results show that the reaction of forming Ti{sub 2}AlC can be achieved below 950 °C, which is 150 °C lower than in the Ti–Al–TiC system and 250 °C lower than for the Ti–Al–C system due to the addition of CNTs. Additionally, the reinforcement of Al{sub 2}O{sub 3} particles was introduced in situ in Ti{sub 2}AlC/TiAl by the drying process and subsequent sintering of the composite powders. Dense Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were obtained by sintering at 1250 °C and exhibited a homogeneous distribution of Ti{sub 2}AlC, Al{sub 2}O{sub 3} and precipitated Ti{sub 3}Al particles and a resulting high hardness.

  19. Low Temperature Cure Powder Coatings

    Science.gov (United States)

    2013-05-01

    operations Minimize worker exposure to VOCs, HAPs, and hexavalent chrome Passed objective AF Engr Qual Plan = Air Force Engineer Quality Plan MIL-PRF...Inconclusive • Inconclusive • Not applicable (N/A) • Passed criteria Reduction of hexavalent chromium use • Passed objective Reduction of hazardous...compliance. The implementation of the OSHA Final Rule designating the permissible exposure limit (PEL) for hexavalent chromium is a significant

  20. Investigation of passive and active silica-tin oxide nanostructured optical fibers fabricated by " inverse dip-coating " and " powder in tube " method based on the chemical sol-gel process and laser emission

    OpenAIRE

    Granger , Geoffroy; Restoin , Christine; Roy , Philippe; Jamier , Raphaël; Rougier , Sébastien; Duclere , Jean-René; Lecomte , André; Dauliat , Romain; Blondy , Jean-Marc

    2015-01-01

    International audience; This paper presents a study of original nanostructured optical fibers based on the SiO 2-SnO 2-(Yb 3+) system. Two different processes have been developed and compared: the sol-gel chemical method associated to the " inverse dip-coating " (IDC) and the " powder in tube " (PIT) process. The microstructural and optical properties of the fibers are studied according to the concentration of SnO 2. X-Ray Diffraction as well as Transmission Electron Microscopy studies show t...

  1. THE INFLUENCE OF THE TEMPERATURE PARAMETER AND ITS DURATION ON THE THICKNESS OF ZINC COATING, ITS STRUCTURE WHILE THERMAL DIFFUSION GALVANIZING IN POWDER-BASED ENVIRONMENTS ZINC-CONTAINING WASTE – GARTTSINKA

    Directory of Open Access Journals (Sweden)

    N. I. Urbanowich

    2013-01-01

    Full Text Available It is showed that an increase of temperature and duration of holding time at termodiffuznom galvanizing in powder medium garttsink–Al2O3 leads to the layer thickness and the size of the samples growth. Coating thickness increases due to δ1k-compact phase having a fine crystalline structure, is in the range of 400–500 °C, with the most intensive growth of layer inside the sample due to the increase of δ1k-compact phase after 3 h-exposure.

  2. Investigation on the parameter optimization and performance of laser cladding a gradient composite coating by a mixed powder of Co50 and Ni/WC on 20CrMnTi low carbon alloy steel

    Science.gov (United States)

    Shi, Yan; Li, Yunfeng; Liu, Jia; Yuan, Zhenyu

    2018-02-01

    In this study, a gradient composite coating was manufactured on 20CrMnTi alloy steel by laser cladding. The laser power, cladding scan velocity and powder flow rate were selected as influencing factors of the orthogonal cladding experiments. The influencing factors were optimized by the comprehensive analysis of Taguchi OA and TOPSIS method. The high significant parameters and the predicted results were confirmed by the ANOVA method. The macromorphology and microstructures are characterized by using laser microscope, SEM, XRD and microhardness tester. Comparison tests of wear resistance of gradient composite coating, 20CrMnTi cemented quenching sample and the 20CrMnTi sample were conducted on the friction-wear tester. The results show that the phases are γ-Co solid solution, Co3B, M23C6 and etc. The interlayers and wear-resisting layer also contain new hard phases as WC, W2C. The microhardness of the gradient coating was increased to 3 times as compared with that of the 20CrMnTi substrate. The wear resistance of the gradient composite coating and 20CrMnTi cemented quenching sample was enhanced to 36.4 and 15.9 times as compared with that of the 20CrMnTi.

  3. Study of the Adherence Mechanism Between the Metal and Inorganic Coating with Mill Addition of Li2Ni8O10 Nano Powder

    Institute of Scientific and Technical Information of China (English)

    QIAN Hui-chun; JIANG Wei-zhong

    2009-01-01

    The adherence strength between the metal and the inorganic coating can be greatly increased by mill addition of Li2Ni8O10,. The interface structure between metal and the inorganic coating with excellent adherence has been studied by investigating the chemical composition and the microstructure as well as elements valence bond on the interface with the help of scanning electron microscope (SEM), electron microprobe, and Auger electron spectroscope (AES). The results show that there is a non-stoichiometrical transitional layer on the interface between metal and the inorganic coating with excellent adherence, the adherence between metal and the non-stoichiometrical transitional layer is achieved by the metallic bond and the adherence between the non-stoichiometrical transitional layer and the inorganic coating is produced by ionic and covalent bond. The non-stoichiometrical transitional layer results in the strong adherence.

  4. Prospects for the Development of Innovative Technology of Supersonic Gas-Powder Surfacing Coatings from Alloys of the System Ni-Cr-B-Si

    Science.gov (United States)

    Radchenko, Mikhail V.; Kiselev, Vadim S.; Shevtsov, Yuri O.; Radchenko, Tatyana B.

    2017-10-01

    The article is devoted to the research and development of technological recommendations of supersonic gas-powder surfacing, an example of the practical use of the developed technology is given. Market research indicates that demand for these products is stable due to the growing quality requirements of components and parts produced by the largest machine-building enterprises of Russia.

  5. (YSZ) powders

    Indian Academy of Sciences (India)

    Unknown

    109–114. © Indian Academy of Sciences. 109 ... Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085, India .... pensions of 900°C calcined YSZ powders. .... The sintered density data of the compacts (sintered at.

  6. Powder Metallurgy Reconditioning of Food and Processing Equipment Components

    Science.gov (United States)

    Nafikov, M. Z.; Aipov, R. S.; Konnov, A. Yu.

    2017-12-01

    A powder metallurgy method is developed to recondition the worn surfaces of food and processing equipment components. A combined additive is composed to minimize the powder losses in sintering. A technique is constructed to determine the powder consumption as a function of the required metallic coating thickness. A rapid method is developed to determine the porosity of the coating. The proposed technology is used to fabricate a wear-resistant defectless metallic coating with favorable residual stresses, and the adhesive strength of this coating is equal to the strength of the base metal.

  7. Powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Hart, M.

    1995-12-31

    the importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940`s, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments.

  8. Powder diffraction

    International Nuclear Information System (INIS)

    Hart, M.

    1995-01-01

    The importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940's, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments

  9. Powder diffractometry

    International Nuclear Information System (INIS)

    Doucet, J.

    1983-01-01

    The new possibilities openned by the synchrotron radiation in the powder diffractometry techniques are presented. This technique is described in a general manner and some aspects which can be developed with the use of the synchrotron radiation are analyzed. (L.C.) [pt

  10. Research into properties of wear resistant ceramic metal plasma coatings

    Science.gov (United States)

    Ivancivsky, V. V.; Skeeba, V. Yu; Zverev, E. A.; Vakhrushev, N. V.; Parts, K. A.

    2018-03-01

    The study considers one of the promising ways to improve the quality of wear resistant plasma ceramic coatings by implementing various powder mixtures. The authors present the study results of the nickel-ceramic and cobalt-ceramic coating properties and describe the specific character of the investigated coatings composition. The paper presents the results of the coating microhardness, chemical and adhesive strength studies. The authors conducted wear resistance tests of composite coatings in comparison with the plasma coatings of initial powder components.

  11. Synthesis of Silver-Doped Titanium TiO2 Powder-Coated Surfaces and Its Ability to Inactivate Pseudomonas aeruginosa and Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Saman Khan

    2013-01-01

    Full Text Available Hard, nonporous environmental surfaces in daily life are now receiving due recognition for their role in reducing the spread of several nosocomial infections. In this work, we established the photokilling effects of 1% silver-doped titanium dioxide TiO2. The nanoparticles synthesized by liquid impregnation method were characterized using X-ray diffraction (XRD, energy dispersive spectroscopy (EDS, and scanning electron microscopy (SEM. The Ag-TiO2 nanoparticle coatings that have been applied on glass and venetian blind surfaces were effective in generating a loss of viability of two bacteria (Pseudomonas aeruginosa and Bacillus subtilis after two hours of illumination under normal light in the visible spectrum. Such surfaces can be applicable to medical and other facilities where the potential for infection should be controlled.

  12. Synthesis of Silver-Doped Titanium TiO2 Powder-Coated Surfaces and Its Ability to Inactivate Pseudomonas aeruginosa and Bacillus subtilis

    International Nuclear Information System (INIS)

    Khan, S.; Qazi, I.A.; Hashmi, I.; Awan, M.A.; Zaidi, N.S.S.

    2013-01-01

    Hard, non porous environmental surfaces in daily life are now receiving due recognition for their role in reducing the spread of several nosocomial infections. In this work, we established the photo killing effects of 1% silver-doped titanium dioxide TiO 2 . The nanoparticles synthesized by liquid impregnation method were characterized using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The Ag-TiO 2 nanoparticle coatings that have been applied on glass and venetian blind surfaces were effective in generating a loss of viability of two bacteria (Pseudomonas aeruginosa and Bacillus subtilis) after two hours of illumination under normal light in the visible spectrum. Such surfaces can be applicable to medical and other facilities where the potential for infection should be controlled

  13. Recobrimentos de poli (tereftalato de etileno depositados em aço por aspersão térmica a partir de pós obtidos em diferentes condições de moagem Thermally sprayed coated carbon steel produced using PET powder obtained in different grinding conditions

    Directory of Open Access Journals (Sweden)

    Luciana Tavares Duarte

    2003-07-01

    Full Text Available Neste trabalho foram analisados recobrimentos de poli(tereftalato de etileno, PET, depositados em aço carbono através da técnica de aspersão térmica à combustão, e produzidos a partir de pós oriundos de processos de moagem, em moinho de bolas e de facas, de garrafas de PET pós-consumo. Algumas condições de moagem foram testadas, tendo-se obtido pós com diferentes características morfológicas. As características morfológicas dos pós e dos recobrimentos foram avaliadas por microscopia óptica e eletrônica, tendo-se observado que o recobrimento apresentava bolhas, provavelmente devido à degradação do polímero. Além disto, os recobrimentos produzidos, bem como as amostras de pó, foram caracterizados por espectroscopia na região do infravermelho, por calorimetria exploratória diferencial e através da determinação de viscosidade intrínseca em solução. Os resultados obtidos mostraram que é possível a produção de aço carbono recoberto com PET através da técnica de aspersão térmica, sendo que o grau de degradação, a morfologia e a distribuição granulométrica dos pós utilizados influenciaram significativamente as características e propriedades dos recobrimentos formados.The main purpose of this work was to study the production of a thermal spray coated poly(ethyleneterephthalate steel. Poly(ethylene terephthalate coatings were made of a thin grinding waste produced by a PET recycling company, and of a PET powder, which was obtained by grinding post-consumer beverage bottles. Some grinding conditions, using a ceramic ball mill, were studied. Scanning Electronic Microscopy (SEM and optical microscopy (OM were used in the study of powder and coating morphologies, and this analysis showed that PET coating presents bubbles due to polymer degradation. PET powder and coating characteristics were investigated using Differential Scanning Calorimetry (DSC and measurements of intrinsic viscosity. It was observed that

  14. Powder technology

    International Nuclear Information System (INIS)

    Agueda, Horacio

    1989-01-01

    Powder technology is experiencing nowadays a great development and has broad application in different fields: nuclear energy, medicine, new energy sources, industrial and home artifacts, etc. Ceramic materials are of daily use as tableware and also in the building industry (bricks, tiles, etc.). However, in machine construction its utilization is not so common. The same happens with metals: powder metallurgy is employed less than traditional metal forming techniques. Both cases deal with powder technology and the forming techniques as far as the final consolidation through sintering processes are very similar. There are many different methods and techniques in the forming stage: cold-pressing, slip casting, injection molding, extrusion molding, isostatic pressing, hot-pressing (which involves also the final consolidation step), etc. This variety allows to obtain almost any desired form no matter how complex it could be. Some applications are very specific as in the case of UO 2 pellets (used as nuclear fuels) but with the same technique and other materials, it is possible to manufacture a great number of different products. This work shows the characteristics and behaviour of two magnetic ceramic materials (ferrites) fabricated in the laboratory of the Applied Research Division of the Bariloche Atomic Center for different purposes. Other materials and products made with the same method are also mentioned. Likewise, densities and shrinkage obtained by different methods of forming (cold-pressing, injection molding, slip casting and extrusion molding) using high-purity alumina (99.5% Al 2 O 3 ). Finally, different applications of such methods are given. (Author) [es

  15. C, N co-doped TiO{sub 2}/TiC{sub 0.7}N{sub 0.3} composite coatings prepared from TiC{sub 0.7}N{sub 0.3} powder using ball milling followed by oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Liang, E-mail: haoliang@tust.edu.cn [Tianjin Key Lab of Integrated Design and On-line Monitoring for Light Industry & Food Machinery and Equipment, Tianjin (China); College of Mechanical Engineering, Tianjin University of Science & Technology, No. 1038 Dagu Nanlu, Hexi District, Tianjin 300222 (China); Wang, Zhenwei, E-mail: 1004329228@qq.com [School of Naval Architecture and Ocean Engineering, Harbin Institute of Technology, Weihai, No. 2, Wenhua West Road, Weihai 264209 (China); Zheng, Yaoqing, E-mail: 13612177268@163.com [College of Mechanical Engineering, Tianjin University of Science & Technology, No. 1038 Dagu Nanlu, Hexi District, Tianjin 300222 (China); Li, Qianqian, E-mail: 1482471595@qq.com [College of Mechanical Engineering, Tianjin University of Science & Technology, No. 1038 Dagu Nanlu, Hexi District, Tianjin 300222 (China); Guan, Sujun, E-mail: sujunguan1221@gmail.com [College of Mechanical Engineering & Graduate School, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Zhao, Qian, E-mail: zhaoqian@tust.edu.cn [Tianjin Key Lab of Integrated Design and On-line Monitoring for Light Industry & Food Machinery and Equipment, Tianjin (China); College of Mechanical Engineering, Tianjin University of Science & Technology, No. 1038 Dagu Nanlu, Hexi District, Tianjin 300222 (China); Cheng, Lijun, E-mail: chenglijun@tust.edu.cn [Tianjin Key Lab of Integrated Design and On-line Monitoring for Light Industry & Food Machinery and Equipment, Tianjin (China); College of Mechanical Engineering, Tianjin University of Science & Technology, No. 1038 Dagu Nanlu, Hexi District, Tianjin 300222 (China); Lu, Yun, E-mail: luyun@faculty.chiba-u.jp [College of Mechanical Engineering & Graduate School, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Liu, Jizi, E-mail: jzliu@njust.edu.cn [Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, No. 200, Xiaolingwei Street, Nanjing 210094 (China)

    2017-01-01

    Highlights: • TiO{sub 2}/TiC{sub 0.7}N{sub 0.3} coatings were prepared by ball milling followed by oxidation. • In situ co-doping of C and N with simultaneous TiO{sub 2} formation was observed. • Improved photocatalytic activity under UV/visible light was noticed. • Synergism in co-doping and heterojunction formation promoted carrier separation. - Abstract: Ball milling followed by heat oxidation was used to prepared C, N co-doped TiO{sub 2} coatings on the surfaces of Al{sub 2}O{sub 3} balls from TiC{sub 0.7}N{sub 0.3} powder. The as-prepared coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrophotometer (UV–vis). The results show that continuous TiC{sub 0.7}N{sub 0.3} coatings were formed after ball milling. C, N co-doped TiO{sub 2}/TiC{sub 0.7}N{sub 0.3} composite coatings were prepared after the direct oxidization of TiC{sub 0.7}N{sub 0.3} coatings in the atmosphere. However, TiO{sub 2} was hardly formed in the surface layer of TiC{sub 0.7}N{sub 0.3} coatings within a depth less than 10 nm during the heat oxidation of TiC{sub 0.7}N{sub 0.3} coatings in carbon powder. Meanwhile, the photocatalytic activity evaluation of these coatings was conducted under the irradiation of UV and visible light. All the coatings showed photocatalytic activity in the degradation of MB no matter under the irradiation of UV or visible light. The C, N co-doped TiO{sub 2}/TiC{sub 0.7}N{sub 0.3} composite coatings showed the most excellent performance. The enhancement under visible light irradiation should attribute to the co-doping of carbon and nitrogen, which enhances the absorption of visible light. The improvement of photocatalytic activity under UV irradiation should attribute to the synergistic effect of C, N co-doping, the formation of rutile-anatase mixed phases and the TiO{sub 2}/TiC{sub 0.7}N{sub 0.3} composite microstructure.

  16. Effect of low current density and low frequency on oxidation resistant and coating activity of coated FeCrAl substrate by γ-Al2O3 powder

    Science.gov (United States)

    Leman, A. M.; Feriyanto, Dafit; Zakaria, Supaat; Sebayang, D.; Rahman, Fakhrurrazi; Jajuli, Afiqah

    2017-09-01

    High oxidation resistant is the needed material properties for material that operates in high temperature such as catalytic converter material. FeCrAl alloy acts as metallic material and is used as substrate material that is coated by ceramic material i.e. γ-Al2O3. The main purpose of this research is to increase oxidation resistant of metallic material as it will help improve the life time of metallic catalytic converter. Ultrasonic technique (UB) and Nickel electroplating technique (EL) were used to achieve the objective. UB was carried out using various time of 1, 1.5, 2, 2.5 and 3 h, in low frequency of 35 kHz and ethanol as the electrolyte. Meanwhile, EL was conducted using various times of 15, 30, 45, 60 and 75 minutes, DC power supply was 1.28A and sulphamate type as the solution. The characterization and analysis were carried out using Scanning Electron Microscopy (SEM) and box furnace at various temperature of 1000, 1100 and 1200 °C. SEM analysis shows the surface morphology of treated and untreated samples. Untreated samples shows finer surface structure as compared to UB and EL samples. It was caused by γ-Al2O3 which was embedded during UB and EL process on the surface of FeCrAl substrate to develop protective oxide layer. The layer was used to protect the substrate from extreme environment condition and temperature operation. Oxidation resistant analysis shows that treated samples had lower mass change as compared to untreated samples. Lowest mass change of treated samples were located at UB 1.5 h and EL at 30 minute with 0.00475 g and 0.00243 g for temperature of 1000 °C, 0.00495 g and 000284 g for temperature of 1100 °C and 0.00519 g and 0.00304 g for temperature 1200 °C, Based on the overall results, it can be concluded that EL 30 minute samples was the appropriate parameter to coat FeCrAl by γ-Al2O3 to develop metallic catalytic converter that is high oxidation resistant in high temperature operation.

  17. Plasma spheroidization and cladding of powders

    Energy Technology Data Exchange (ETDEWEB)

    Petrunichev, V.A.; Averin, V.V.; Sorokin, L.M.; Koroleva, E.B.

    1987-02-01

    With reference to experimental results for nickel and chromium alloys, it is shown that complex alloy powders can be spheroidized in plasma discharges using an argon plasma with hydrogen. The spheroidizing process is accompanied by the reduction of surface oxides, with uniform element distribution within the particles; the granulometric composition of the particles is preserved. It is also shown that plasma technology can be used for producing metal-clad oxide and carbide powders, which improve the performance of cermets and coatings.

  18. Coating and Characterization of Mock and Explosive Materials

    Directory of Open Access Journals (Sweden)

    Emily M. Hunt

    2012-01-01

    Full Text Available This project develops a method of manufacturing plastic-bonded explosives by using use precision control of agglomeration and coating of energetic powders. The energetic material coating process entails suspending either wet or dry energetic powders in a stream of inert gas and contacting the energetic powder with atomized droplets of a lacquer composed of binder and organic solvent. By using a high-velocity air stream to pneumatically convey the energetic powders and droplets of lacquer, the energetic powders are efficiently wetted while agglomerate drying begins almost immediately. The result is an energetic powder uniformly coated with binder, that is, a PBX, with a high bulk density suitable for pressing. Experiments have been conducted using mock explosive materials to examine coating effectiveness and density. Energetic materials are now being coated and will be tested both mechanically and thermally. This allows for a comprehensive comparison of the morphology and reactivity of the newly coated materials to previously manufactured materials.

  19. Next Generation Thermal Barrier Coatings for the Gas Turbine Industry

    Science.gov (United States)

    Curry, Nicholas; Markocsan, Nicolaie; Li, Xin-Hai; Tricoire, Aurélien; Dorfman, Mitch

    2011-01-01

    The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.

  20. Net Shape Rapid Manufacturing Using Nano Encapsulated Powders, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this STTR is to determine the capability of Net Shape LENS processing with Nano-coated powders. The unique composites produced using regualr...

  1. Electrostatic coating technologies for food processing.

    Science.gov (United States)

    Barringer, Sheryl A; Sumonsiri, Nutsuda

    2015-01-01

    The application of electrostatics in both powder and liquid coating can improve the quality of food, such as its appearance, aroma, taste, and shelf life. Coatings can be found most commonly in the snack food industry, as well as in confectionery, bakery, meat and cheese processing. In electrostatic powder coating, the most important factors influencing coating quality are powder particle size, density, flowability, charge, and resistivity, as well as the surface properties and characteristics of the target. The most important factors during electrostatic liquid coating, also known as electrohydrodynamic coating, include applied voltage and electrical resistivity and viscosity of the liquid. A good understanding of these factors is needed for the design of optimal coating systems for food processing.

  2. Low Temperature Cure Powder Coatings (LTCPC)

    Science.gov (United States)

    2010-10-01

    Dr. Glen Merfeld, General Electric Global Research evaluated and optimized the formulation, and cure and performance parameters of candidate LTCPC...Unacceptable test result = Marginal test result = Acceptable test result 80 therefore suffer from brittleness at extremely low temperatures. NASA’s

  3. Metallography of powder metallurgy materials

    International Nuclear Information System (INIS)

    Lawley, Alan; Murphy, Thomas F.

    2003-01-01

    The primary distinction between the microstructure of an ingot metallurgy/wrought material and one fabricated by the powder metallurgy route of pressing followed by sintering is the presence of porosity in the latter. In its various morphologies, porosity affects the mechanical, physical, chemical, electrical and thermal properties of the material. Thus, it is important to be able to characterize quantitatively the microstructure of powder metallurgy parts and components. Metallographic procedures necessary for the reliable characterization of microstructures in powder metallurgy materials are reviewed, with emphasis on the intrinsic challenges presented by the presence of porosity. To illustrate the utility of these techniques, five case studies are presented involving powder metallurgy materials. These case studies demonstrate problem solving via metallography in diverse situations: failure of a tungsten carbide-coated precipitation hardening stainless steel, failure of a steel pump gear, quantification of the degree of sinter (DOS), simulation of performance of a porous filter using automated image analysis, and analysis of failure in a sinter brazed part assembly

  4. Foundations of powder metallurgy

    International Nuclear Information System (INIS)

    Libenson, G.A.

    1987-01-01

    Consideration is being given to physicochemical foundations and technology of metal powders, moulding and sintering of bars, made of them or their mixtures with nonmetal powders. Data on he design of basic equipment used in the processes of powder metallurgy and its servicing are presented. General requirements of safety engineering when fabricating metal powders and products of them are mentioned

  5. Fundamentals of powder metallurgy

    International Nuclear Information System (INIS)

    Khan, I.H.; Qureshi, K.A.; Minhas, J.I.

    1988-01-01

    This book is being presented to introduce the fundamentals of technology of powder metallurgy. An attempt has been made to present an overall view of powder metallurgy technology in the first chapter, whereas chapter 2 to 8 deal with the production of metal powders. The basic commercial methods of powder production are briefly described with illustrations. Chapter 9 to 12 describes briefly metal powder characteristics and principles of testing, mixing, blending, conditioning, compaction and sintering. (orig./A.B.)

  6. How PE tape performs under concrete coating

    International Nuclear Information System (INIS)

    Dritt, H.J.

    1984-01-01

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

  7. 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

  8. Effects of Bond Coating on NiCrBSi-Mo Composite Functional Coating Properties in Plasma Spraying NiCrBSi-Mo/Ni Coating

    OpenAIRE

    DU Ji-yu; LI Fang-yi; LU Hai-yang; SHANG Jian-tong; LI Zhen

    2017-01-01

    Nickel-based bond coating and composite functional coating were sprayed on leaf blade steel material FV520B successively by using air plasma spraying system. NiCrBSi-Mo powder deposition rate, coating porosity, bonding strength and surface hardness were tested. The results indicate that, for the NiCrBSi-Mo/Ni coating, bond coating with 180-220μm thickness can improve NiCrBSi-Mo powder deposition rate while the surface coating with lower porosity, higher bonding strength and high hardness is p...

  9. Multi-Layered Effects of Fe on EMI Shielding of Sn-Al Hotel Architectural Powder

    OpenAIRE

    Hung Fei-Shuo

    2016-01-01

    No evident effect in shielding efficiency is observed when the electromagnetic wave-absorbing coating materials were applied in single layers because of the dispersing nature of the powder. When increased to two-layer coating, shielding effects were evident at both high and low frequencies, with greater shielding efficiency at low frequencies over high frequencies. It is worth noting that when increased to three-layer coating, as the weight percentage of powdered Fe increased from 5% to 8% , ...

  10. Aluminum powder metallurgy processing

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  11. Electrical conductivity of metal powders under pressure

    Science.gov (United States)

    Montes, J. M.; Cuevas, F. G.; Cintas, J.; Urban, P.

    2011-12-01

    A model for calculating the electrical conductivity of a compressed powder mass consisting of oxide-coated metal particles has been derived. A theoretical tool previously developed by the authors, the so-called `equivalent simple cubic system', was used in the model deduction. This tool is based on relating the actual powder system to an equivalent one consisting of deforming spheres packed in a simple cubic lattice, which is much easier to examine. The proposed model relates the effective electrical conductivity of the powder mass under compression to its level of porosity. Other physically measurable parameters in the model are the conductivities of the metal and oxide constituting the powder particles, their radii, the mean thickness of the oxide layer and the tap porosity of the powder. Two additional parameters controlling the effect of the descaling of the particle oxide layer were empirically introduced. The proposed model was experimentally verified by measurements of the electrical conductivity of aluminium, bronze, iron, nickel and titanium powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

  12. Spherical rhenium metal powder

    International Nuclear Information System (INIS)

    Leonhardt, T.; Moore, N.; Hamister, M.

    2001-01-01

    The development of a high-density, spherical rhenium powder (SReP) possessing excellent flow characteristics has enabled the use of advanced processing techniques for the manufacture of rhenium components. The techniques that were investigated were vacuum plasma spraying (VPS), direct-hot isostatic pressing (D-HIP), and various other traditional powder metallurgy processing methods of forming rhenium powder into near-net shaped components. The principal disadvantages of standard rhenium metal powder (RMP) for advanced consolidation applications include: poor flow characteristics; high oxygen content; and low and varying packing densities. SReP will lower costs, reduce processing times, and improve yields when manufacturing powder metallurgy rhenium components. The results of the powder characterization of spherical rhenium powder and the consolidation of the SReP are further discussed. (author)

  13. Porous Structure Characterization in Titanium Coating for Surgical Implants

    Directory of Open Access Journals (Sweden)

    M.V. Oliveira

    2002-09-01

    Full Text Available Powder metallurgy techniques have been used to produce controlled porous structures, such as the porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface improving fixation. This work presents the processing and characterization of titanium porous coatings of different porosity levels, processed through powder metallurgy techniques. Pure titanium sponge powders were used for coating and Ti-6Al7Nb powder metallurgy rods were used as substrates. Characterization was made through quantitative metallographic image analysis using optical light microscope for coating porosity data and SEM analysis for evaluation of the coating/substrate interface integrity. The results allowed optimization of the processing parameters in order to obtain porous coatings that meet the requirements for use as implants.

  14. Sealed glass coating of high temperature ceramic superconductors

    Science.gov (United States)

    Wu, Weite; Chu, Cha Y.; Goretta, Kenneth C.; Routbort, Jules L.

    1995-01-01

    A method and article of manufacture of a lead oxide based glass coating on a high temperature superconductor. The method includes preparing a dispersion of glass powders in a solution, applying the dispersion to the superconductor, drying the dispersion before applying another coating and heating the glass powder dispersion at temperatures below oxygen diffusion onset and above the glass melting point to form a continuous glass coating on the superconductor to establish compressive stresses which enhance the fracture strength of the superconductor.

  15. Fe-based nanocrystalline powder cores with ultra-low core loss

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiangyue, E-mail: wangxiangyue1986@163.com [China Iron and Steel Research Institute Group, Beijing 100081 (China); Center of Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Lu, Zhichao; Lu, Caowei; Li, Deren [China Iron and Steel Research Institute Group, Beijing 100081 (China); Center of Advanced Technology and Materials Co., Ltd., Beijing 100081 (China)

    2013-12-15

    Melt-spun amorphous Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 15.5}B{sub 7} alloy strip was crushed to make flake-shaped fine powders. The passivated powders by phosphoric acid were mixed with organic and inorganic binder, followed by cold compaction to form toroid-shaped bonded powder-metallurgical magnets. The powder cores were heat-treated to crystallize the amorphous structure and to control the nano-grain structure. Well-coated phosphate-oxide insulation layer on the powder surface decreased the the core loss with the insulation of each powder. FeCuNbSiB nanocrystalline alloy powder core prepared from the powder having phosphate-oxide layer exhibits a stable permeability up to high frequency range over 2 MHz. Especially, the core loss could be reduced remarkably. At the other hand, the softened inorganic binder in the annealing process could effectively improve the intensity of powder cores. - Highlights: • Fe-based nanocrystalline powder cores were prepared with low core loss. • Well-coated phosphate-oxide insulation layer on the powder surface decreased the core loss. • Fe-based nanocrystalline powder cores exhibited a stable permeability up to high frequency range over 2 MHz. • The softened inorganic binder in the annealing process could effectively improve the intensity of powder cores.

  16. SAF line powder operations

    International Nuclear Information System (INIS)

    Frederickson, J.R.; Horgos, R.M.

    1983-10-01

    An automated nuclear fuel fabrication line is being designed for installation in the Fuels and Materials Examination Facility (FMEF) near Richland, Washington. The fabrication line will consist of seven major process systems: Receiving and Powder Preparation; Powder Conditioning; Pressing and Boat Loading; Debinding, Sintering, and Property Adjustment; Boat Transport; Pellet Inspection and Finishing; and Pin Operations. Fuel powder processing through pellet pressing will be discussed in this paper

  17. Two layer powder pressing

    International Nuclear Information System (INIS)

    Schreiner, H.

    1979-01-01

    First, significance and advantages of sintered materials consisting of two layers are pointed out. By means of the two layer powder pressing technique metal powders are formed resulting in compacts with high accuracy of shape and mass. Attributes of basic powders, different filling methods and pressing techniques are discussed. The described technique is supposed to find further applications in the field of two layer compacts in the near future

  18. Operation whey powder

    International Nuclear Information System (INIS)

    Brunner, E.

    1987-01-01

    The odyssey of the contaminated whey powder finally has come to an end, and the 5000 tonnes of whey now are designated for decontamination by means of an ion exchange technique. The article throws light upon the political and economic reasons that sent the whey powder off on a chaotic journey. It is worth mentioning in this context that the natural radioactivity of inorganic fertilizers is much higher than that of the whey powder in question. (HP) [de

  19. Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying

    OpenAIRE

    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

    2015-01-01

    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 t...

  20. Pharmaceutical powder compaction technology

    National Research Council Canada - National Science Library

    Çelik, Metin

    2011-01-01

    ... through the compaction formulation process and application. Compaction of powder constituents both active ingredient and excipients is examined to ensure consistent and reproducible disintegration and dispersion profiles...

  1. Process for applying a superconductive powder to a wide variety of substrates

    Science.gov (United States)

    Hooker, Matthew W.; Wise, Stephanie A.; Tran, Sang Q.

    1992-12-01

    A fine superconducting powder such as YBa2Cu3O(7-x), wherein x is less than one, is blended into a liquid mixture comprising an epoxy resin and a thinner. This liquid mixture with the blended superconducting powder is coated onto a substrate. Next, the thinner is evaporated and the remaining coating cured, resulting in a coating of cured epoxy resin having superconducting powder suspended therein. This coating exhibits the Meissner effect, i.e., it expels a magnetic flux which protects the substrate from external magnetic interference. Since the coated substrate need only be heated for evaporation and curing at relatively low temperatures compared to firing, the superconducting coating can be applied to a wide variety of different materials.

  2. Biaxially textured articles formed by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-05

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100} orientation texture; and further having a Curie temperature less than that of pure Ni.

  3. 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.

  4. Synthesis and characterization of nanocrystalline Cu-Al coatings

    International Nuclear Information System (INIS)

    Lau, M.L.; He, J.; Schweinfest, R.; Ruehle, M.; Levi, C.G.; Lavernia, E.J.

    2003-01-01

    Commercially pure Cu and Al powders were blended in a 90:10 ratio by weight and then mechanically milled in methanol or in liquid nitrogen. The milled powders, as well as as-blended (non-milled) powder, were deposited as coatings using high velocity oxygen fuel thermal spraying. Scanning and transmission electron microscopy techniques were used to investigate the microstructure of the powders and coatings. The results showed that milling of the powders in methanol induced the conversion of most of the Al into amorphous Al 2 O 3 , precluding the desired mechanical alloying. This experimental observation was consistent with available thermodynamic data. In contrast, cryomilling exhibited no significant oxidation and induced mechanical alloying of the powders, albeit incomplete. The non-milled powder generated a coating with a bimodal grain structure consisting of fine Cu grains and coarse Al grains. Amorphous oxide regions and coarse Al grains were observed intermixed with the finer Cu matrix in the coatings sprayed using the powders milled in methanol. Coatings based on cryomilled powders consisted primarily of equiaxed Cu grains and twinned martensite regions, with occasional inclusion of elongated amorphous Al 2 O 3 regions

  5. Mixed zirconia calcium phosphate coatings for dental implants: Tailoring coating stability and bioactivity potential

    International Nuclear Information System (INIS)

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Destri, Giovanni Li; Marletta, Giovanni; Rezwan, Kurosch

    2015-01-01

    Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants. - Highlights: • Different ratios of zirconia (TZ) and calcium phosphate (CP) were deposited on zirconia substrates. • Enhancement of TZ content in mixed coatings increased coating stability. • Enhancement of CP content in mixed coatings increased bioactivity. • All tested coating compositions were non-toxic

  6. Mixed zirconia calcium phosphate coatings for dental implants: Tailoring coating stability and bioactivity potential

    Energy Technology Data Exchange (ETDEWEB)

    Pardun, Karoline [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Treccani, Laura, E-mail: treccani@uni-bremen.de [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Volkmann, Eike [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany); Streckbein, Philipp [University Hospital, Justus-Liebig-University Giessen, Department of Cranio-Maxillo-Facial Surgery, Klinikstrasse 33, 35385 Giessen (Germany); Heiss, Christian [University Hospital of Giessen-Marburg, Department of Trauma Surgery, Rudolf-Buchheim-Strasse 7, 35385 Giessen, Germany, (Germany); Laboratory of Experimental Surgery, Kerkraderstrasse 9, 35392 Giessen (Germany); Destri, Giovanni Li; Marletta, Giovanni [Laboratory for Molecular Surfaces and Nanotechnology (LAMSUN), Department of Chemistry, University of Catania and CSGI, Viale A. Doria 6, 95125 Catania (Italy); Rezwan, Kurosch [University of Bremen, Advanced Ceramics, Am Biologischen Garten 2, 28359 Bremen (Germany)

    2015-03-01

    Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants. - Highlights: • Different ratios of zirconia (TZ) and calcium phosphate (CP) were deposited on zirconia substrates. • Enhancement of TZ content in mixed coatings increased coating stability. • Enhancement of CP content in mixed coatings increased bioactivity. • All tested coating compositions were non-toxic.

  7. Sintered aluminium powders

    International Nuclear Information System (INIS)

    Stepanova, M.G.; Matveev, B.I.

    1974-01-01

    The mechanical and physical properties of aluminium powder alloys and the various methods employed to produce them are considered. Data are given on the hardening of the alloys SAP and SPAK-4, as well as the powder-alloy system Al-Cr-Zr. (L.M.)

  8. A new high temperature resistant glass–ceramic coating for gas ...

    Indian Academy of Sciences (India)

    Unknown

    resultant coatings showed presence of a number of microcrystalline phases. SEM micrographs ... processing of two novel glass–ceramic coating materials, ... stainless steel tray to yield frit (a friable glassy material). .... Frit (– 20 mesh) powder.

  9. Self-Healing anticorrosive coatings

    DEFF Research Database (Denmark)

    Nesterova, Tatyana

    %. The number is lower than anticipated and needs to be confirmed. Finally, a 3-D model, based on Monte-Carlo simulations, has been developed for prediction of healing efficiency of a microcapsule-based anticorrosive coating. Two kinds of cracks were considered: cracks accommodated within the bulk coating...... associated with development and testing of this type of coating. A laboratory investigation, to identify the most suitable method for production of mechanically stable (filled with industrially relevant core materials) and forming a free-flowing powder upon drying microcapsules, has been performed. Four...... reduces the intensity of crack formation (both in number and length) compared to filler-containing coatings and prevents the coating from flaking upon damage. Based on specular gloss measurements, a preliminary critical pigment (microcapsule) concentration (CPVC) value was estimated to about 30 vol...

  10. Thermal Spray Coating of Tungsten for Tokamak Device

    International Nuclear Information System (INIS)

    Jiang Xianliang; Gitzhofer, F; Boulos, M I

    2006-01-01

    Thermal spray, such as direct current (d.c.) plasma spray or radio frequency induced plasma spray, was used to deposit tungsten coatings on the copper electrodes of a tokamak device. The tungsten coating on the outer surface of one copper electrode was formed directly through d.c. plasma spraying of fine tungsten powder. The tungsten coating/lining on the inner surface of another copper electrode could be formed indirectly through induced plasma spraying of coarse tungsten powder. Scanning electron microscopy (SEM) was used to examine the cross section and the interface of the tungsten coating. Energy Dispersive Analysis of X-ray (EDAX) was used to analyze the metallic elements attached to a separated interface. The influence of the particle size of the tungsten powder on the density, cracking behavior and adhesion of the coating is discussed. It is found that the coarse tungsten powder with the particle size of 45 ∼ 75 μm can be melted and the coating can be formed only by using induced plasma. The coating deposited from the coarse powder has much higher cohesive strength, adhesive strength and crack resistance than the coating made from the fine powder with a particle size of 5 μm

  11. The choice of the conditions to receive the electrolytic zinc powders for metal-rich compositions

    Directory of Open Access Journals (Sweden)

    A. V. Patrushev

    2015-03-01

    Full Text Available In the work a method of obtaining highly dispersed zinc powders by electrolysis and comparison of the properties of zinc-rich compositions prepared using as a pigment zinc powders obtained by different methods is provided. Conducted measurements have shown that the electrical conductivity of zinc-rich coatings comprising electrolytic zinc powder does not inferior to the conductivity of the film with PZHD-0 powder obtained by the  evaporation-condensation method, despite the significant difference in the amount of zinc pigment. On the basis of the received data one can conclude that the use of electrolytic zinc powder as a pigment will significantly save zinc.

  12. Measurement of loose powder density

    International Nuclear Information System (INIS)

    Akhtar, S.; Ali, A.; Haider, A.; Farooque, M.

    2011-01-01

    Powder metallurgy is a conventional technique for making engineering articles from powders. Main objective is to produce final products with the highest possible uniform density, which depends on the initial loose powder characteristics. Producing, handling, characterizing and compacting materials in loose powder form are part of the manufacturing processes. Density of loose metallic or ceramic powder is an important parameter for die design. Loose powder density is required for calculating the exact mass of powder to fill the die cavity for producing intended green density of the powder compact. To fulfill this requirement of powder metallurgical processing, a loose powder density meter as per ASTM standards is designed and fabricated for measurement of density. The density of free flowing metallic powders can be determined using Hall flow meter funnel and density cup of 25 cm/sup 3/ volume. Density of metal powders like cobalt, manganese, spherical bronze and pure iron is measured and results are obtained with 99.9% accuracy. (author)

  13. Coating Properties of WC-Ni Cold Spray Coating for the Application in Secondary Piping System of Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, JeongWon; Kim, Seunghyun; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2015-10-15

    As a result of FAC(flow accelerated corrosion), severe accidents, failure of carbon steel like a Mihama Unit-3 occurred. Chemical composition change of carbon steel or coating to inner surface is one of methods to improve corrosion properties. Among them, thermal spray coating is convenient solution to apply at industry. Powder is melted at blast furnace and ejected to substrate. After adhesion, substrate and coating layer is cooled down and coated layer protects steel from corrosion finally. However high thermal energy is transferred to substrate and coating layer so it leads high thermal residual stress in coating procedure. Besides, high temperature for melting powder makes unexpected chemical reaction of powder like an oxidation or carburization. Whereas, cold spray uses low temperature comparing with other thermal spray. Thermal energy is used for not melting powder but high kinetic energy of powder and plastic deformation during collision. Therefore, fuel such as oxygen-acetylene gas is not needed. It needs carrier gas, compressed air, nitrogen or helium, to increase kinetic energy of powder and move powder to substrate. Comparing cold spray with high velocity oxy fuel (HVOF), one of thermal spray, cold spray coating layer contains only WC and Co. One of other problem about WC is brittleness during coating. To improve deformability of WC, binder metal is added. For example, Co, Cr, Ni, Cu, Al, Fe or etc. Additionally, binder metal lowering melting temperature of composite powder increases coating properties. Among them, Co which is widely used as binder metal maintains mechanical properties like a hardness and improves corrosion properties. Therefore Co is not suitable for binder metal of WC coating. In contrast, Ni has better corrosion resistance to alkaline environment and makes lower melting temperature. Moreover, in a view of cold spray, FCC structure has better deformability than BCC or HCP, and BCC has lowest deformability. WC is BCC structure so it

  14. OIL SOLUTIONS POWDER

    Science.gov (United States)

    Technical product bulletin: aka OIL SOLUTIONS POWDER, SPILL GREEN LS, this miscellaneous oil spill control agent used in cleanups initially behaves like a synthetic sorbent, then as a solidifier as the molecular microencapsulating process occurs.

  15. Preparation of copper and silicon/copper powders by a gas ...

    Indian Academy of Sciences (India)

    Pure and silicon-coated metal copper nano to submicron-sized powders were prepared by gas evaporation and condensation. This powder was synthesized by using an industrial electron accelerator, ELV-6, with Ar as the carrier gas. Vapour from the liquefied metal surface was transferred to the cold zone by the carrier ...

  16. Experimental study of the polymer powder film thickness uniformity produced by the corona discharge

    Science.gov (United States)

    Fazlyyyakhmatov, Marsel

    2017-01-01

    The results of an experimental study of the polymer powder film thickness uniformity are presented. Polymer powder films are produced by the electrostatic field of corona discharge. Epoxy and epoxy-polyester powder films with thickness in the range of 30-120 microns are studied. Experimentally confirmed possibility of using these coatings as protective matching layer of piezoceramic transducers at frequencies of 0.5-15 MHz.

  17. Magnetically responsive enzyme powders

    Energy Technology Data Exchange (ETDEWEB)

    Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

    2015-04-15

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

  18. Characteristics of Inconel Powders for Powder-Bed Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Quy Bau Nguyen

    2017-10-01

    Full Text Available In this study, the flow characteristics and behaviors of virgin and recycled Inconel powder for powder-bed additive manufacturing (AM were studied using different powder characterization techniques. The results revealed that the particle size distribution (PSD for the selective laser melting (SLM process is typically in the range from 15 μm to 63 μm. The flow rate of virgin Inconel powder is around 28 s·(50 g−1. In addition, the packing density was found to be 60%. The rheological test results indicate that the virgin powder has reasonably good flowability compared with the recycled powder. The inter-relation between the powder characteristics is discussed herein. A propeller was successfully printed using the powder. The results suggest that Inconel powder is suitable for AM and can be a good reference for researchers who attempt to produce AM powders.

  19. Biaxially textured articles formed by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100} orientation texture; and further having a Curie temperature less than that of pure Ni.

  20. Electroplasma coatings based on silicon-containing hydroxyapatite: Technology and properties

    Science.gov (United States)

    Lyasnikova, A. V.; Markelova, O. A.

    2016-09-01

    IR analysis and the plasma deposition of silicon-containing hydroxyapatite powder have been carried out. It has been shown that the coating exhibits developed morphology and consists of molten powder (including nanosize) particles uniformly distributed over the entire surface. The adhesion characteristics have been calculated and scanning electron microscope images of the resultant coating have been analyzed.

  1. Powder neutron diffractometers HRPT and DMCG

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P; Doenni, A; Staub, U; Zolliker, M [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    Basic properties and applications of SINQ powder neutron diffractometers are described. For optimum use of the continuous neutron beams these instruments are equipped with position sensitive detectors, and both high-intensity and high-resolution modes of operation are possible. HRPT attaining resolutions {delta}d/d{<=}10{sup -3}, d=lattice spacing, at a thermal neutron channel of the target station and DMCG at a cold neutron guide coated with m=2 supermirrors, are complementary concerning the applications: the former will be mainly used for structural studies and the latter to investigate magnetic ordering phenomena. (author) figs., tabs., refs.

  2. Demonstration of pharmaceutical tablet coating process by injection molding technology.

    Science.gov (United States)

    Puri, Vibha; Brancazio, David; Harinath, Eranda; Martinez, Alexander R; Desai, Parind M; Jensen, Keith D; Chun, Jung-Hoon; Braatz, Richard D; Myerson, Allan S; Trout, Bernhardt L

    2018-01-15

    We demonstrate the coating of tablets using an injection molding (IM) process that has advantage of being solvent free and can provide precision coat features. The selected core tablets comprising 10% w/w griseofulvin were prepared by an integrated hot melt extrusion-injection molding (HME-IM) process. Coating trials were conducted on a vertical injection mold machine. Polyethylene glycol and polyethylene oxide based hot melt extruded coat compositions were used. Tablet coating process feasibility was successfully demonstrated using different coating mold designs (with both overlapping and non-overlapping coatings at the weld) and coat thicknesses of 150 and 300 μm. The resultant coated tablets had acceptable appearance, seal at the weld, and immediate drug release profile (with an acceptable lag time). Since IM is a continuous process, this study opens opportunities to develop HME-IM continuous processes for transforming powder to coated tablets. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Ultrafine hydrogen storage powders

    Science.gov (United States)

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  4. Plasma spheroidizing and cladding of powders

    International Nuclear Information System (INIS)

    Petrunichev, V.A.; Averin, V.V.; Sorokin, L.M.; Koroleva, E.B.

    1987-01-01

    Arc and high-frequency plasmatrons are used for spheroidizing nickel and chromium-base alloy particles. Different plasma-forming medium compositions are used in the arc variant and the effect of these media on the plasma treatment product is demonstrated. For a high-frequency plasmatron, a long time of plasma contact with the powder leads to the transfer of the part of the material from the treated particles into vaporous state with subsequent condensation at the outlet from the discharge zone. Results of investigations into the formation of metal coatings on oxide and carbide particles during plasma-arc action are also presented. Representative data on the output of particles with coating are obtained and factors, providing for the optimal particle cladding conditions, are indicated

  5. Weighing fluidized powder

    International Nuclear Information System (INIS)

    Adomitis, J.T.; Larson, R.I.

    1980-01-01

    Fluidized powder is discharged from a fluidizing vessel into a container. Accurate metering is achieved by opening and closing the valve to discharge the powder in a series of short-duration periods until a predetermined weight is measured by a load cell. The duration of the discharge period may be increased in inverse proportion to the amount of powder in the vessel. Preferably the container is weighed between the discharge periods to prevent fluctuations resulting from dynamic effects. The gas discharged into the container causes the pressures in the vessel and container to equalize thereby decreasing the rate of discharge and increasing the accuracy of metering as the weight reaches the predetermined value. (author)

  6. Baking Powder Wars

    OpenAIRE

    Civitello, Linda

    2017-01-01

    How did a mid-nineteenth century American invention, baking powder, replace yeast as a leavening agent and create a culinary revolution as profound as the use of yeast thousands of years ago?The approach was two-pronged and gendered: business archives, U.S. government records and lawsuits revealed how baking powder was created, marketed, and regulated. Women’s diaries and cookbooks—personal, corporate, community, ethnic—from the eighteenth century to internet blogs showed the use women made o...

  7. Powdering of Hot-dip Galvannealed steel using Finite Element Analysis

    International Nuclear Information System (INIS)

    Kim, D. W.; Jang, Y. C.; Lee, Y. S.; Kim, S. I.

    2007-01-01

    Demand for hot-dip galvannealed steel has been increased due to it high corrosion resistance, paintability, and formability in automotive industry. Coating of Hot-dip galvannealed steel consists of various Fe-Zn intermetallic compounds. Since the coating is hard and therefore it is very brittle, the surface of steel sheet is easy to be ruptured during second manufacturing processing. This is called as powdering. Hence, various research have been carried out to prohibit powdering for improving the quality of GA steel during second manufacturing processing. This paper performed finite element analysis to evaluate local powdering and compared FEA results with V-bending test. The effects of punch radius and coating strength on the powdering was examined

  8. Plasma sprayed alumina-titania coatings

    International Nuclear Information System (INIS)

    Steeper, T.J.; Rotolico, A.J.; Nerz, J.E.; Riggs, W.L. II; Varacalle, D.J. Jr.; Wilson, G.C.

    1992-01-01

    This paper presents an experimental study of the air plasma spraying (APS) of alumina-titania powder using argon-hydrogen working gases. This powder system is being used in the fabrication of heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic testing. Experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical spray parameters in a systematic design of experiments in order to display the range of plasma processing conditions and their effect on the resultant coatings. The coatings were characterized by hardness and electrical tests, surface profilometry, image analysis, optical metallography, and x-ray diffraction. Coating qualities are discussed with respect to dielectric strength, hardness, porosity, surface roughness, deposition efficiency, and microstructure. attempts are made to correlate the features of the coatings with the changes in operating parameters

  9. Mechanical particle coating using polymethacrylate nanoparticle agglomerates for the preparation of controlled release fine particles: The relationship between coating performance and the characteristics of various polymethacrylates.

    Science.gov (United States)

    Kondo, Keita; Kato, Shinsuke; Niwa, Toshiyuki

    2017-10-30

    We aimed to understand the factors controlling mechanical particle coating using polymethacrylate. The relationship between coating performance and the characteristics of polymethacrylate powders was investigated. First, theophylline crystals were treated using a mechanical powder processor to obtain theophylline spheres (grindability of the agglomerates were attributed to differences in particle structure, resulting from consolidation between colloidal particles. High-grindability agglomerates exhibited higher pulverization as their glass transition temperature (T g ) increased and the further pulverization promoted coating. We therefore conclude that the minimization of polymethacrylate powder by pulverization is an important factor in mechanical particle coating using polymethacrylate with low deformability. Meanwhile, when product temperature during coating approaches T g of polymer, polymethacrylate was soften to show high coating performance by plastic deformation. The effective coating by this mechanism may be accomplished by adjusting the temperature in the processor to the T g . Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Characterization of ceramic powder compacts

    International Nuclear Information System (INIS)

    Yanai, K.; Ishimoto, S.; Kubo, T.; Ito, K.; Ishikawa, T.; Hayashi, H.

    1995-01-01

    UO 2 and Al 2 O 3 powder packing structures in cylindrical powder compacts are observed by scanning electron microscopy using polished cross sections of compacts fixed by low viscosity epoxy resin. Hard aggregates which are not destroyed during powder compaction are observed in some of the UO 2 powder compacts. A technique to measure local density in powder compacts is developed based on counting characteristic X-ray intensity by energy dispersive X-ray analysis (EDX). The local density of the corner portion of the powder compact fabricated by double-acting dry press is higher than that of the inner portion. ((orig.))

  11. Magnetically responsive enzyme powders

    Czech Academy of Sciences Publication Activity Database

    Pospišková, K.; Šafařík, Ivo

    2015-01-01

    Roč. 380, APR 2015 (2015), s. 197-200 ISSN 0304-8853 R&D Projects: GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : enzyme powders * cross-linking * magnetic modification * magnetic separation * magnetic iron oxides particles * microwave-assisted synthesis Subject RIV: CE - Biochemistry Impact factor: 2.357, year: 2015

  12. Powder neutron diffractometers

    International Nuclear Information System (INIS)

    Adib, M.

    2002-01-01

    Basic properties and applications of powder neutron Diffractometers are described for optimum use of the continuous neutron beams. These instruments are equipped with position sensitive detectors, neutron guide tubes, and both high intensity and high resolution modes of operation are possible .The principles of both direct and Fourier reverse time-of-flight neutron Diffractometers are also given

  13. Laser cladding with powder

    NARCIS (Netherlands)

    Schneider, M.F.; Schneider, Marcel Fredrik

    1998-01-01

    This thesis is directed to laser cladding with powder and a CO2 laser as heat source. The laser beam intensity profile turned out to be an important pa6 Summary rameter in laser cladding. A numerical model was developed that allows the prediction of the surface temperature distribution that is

  14. Chemical Processing of Nanostructured Coatings

    Science.gov (United States)

    2000-01-01

    in the literature ranging from IR imaging to anti-scratch to smart windows and waveguides. Uhlmann and Towee have taken a survey of the sol-gel...Proteins and enzymes can be encapsulated in silica glass (12), while still retaining their activity. Sol-gel coatings (13,14) of hydroxyapatite should also...Technology, 13, 261-65. 14. Lolpatin, C. M. Pizziloni, V., Alford, T. L., and Lawsaon, T (1998) Hydroxyapatite powders ad thin films prepared by sol

  15. Stochastic Computer Simulation of Cermet Coatings Formation

    OpenAIRE

    Solonenko, Oleg P.; Jordan, Vladimir I.; Blednov, Vitaly A.

    2015-01-01

    An approach to the modeling of the process of the formation of thermal coatings lamellar structure, including plasma coatings, at the spraying of cermet powders is proposed. The approach based on the theoretical fundamentals developed which could be used for rapid and sufficiently accurate prediction of thickness and diameter of cermet splats as well as temperature at interface “flattening quasi-liquid cermet particle-substrate” depending on the key physical parameters (KPPs): temperature, ve...

  16. Laser cladding of bioactive glass coatings.

    Science.gov (United States)

    Comesaña, R; Quintero, F; Lusquiños, F; Pascual, M J; Boutinguiza, M; Durán, A; Pou, J

    2010-03-01

    Laser cladding by powder injection has been used to produce bioactive glass coatings on titanium alloy (Ti6Al4V) substrates. Bioactive glass compositions alternative to 45S5 Bioglass were demonstrated to exhibit a gradual wetting angle-temperature evolution and therefore a more homogeneous deposition of the coating over the substrate was achieved. Among the different compositions studied, the S520 bioactive glass showed smoother wetting angle-temperature behavior and was successfully used as precursor material to produce bioactive coatings. Coatings processed using a Nd:YAG laser presented calcium silicate crystallization at the surface, with a uniform composition along the coating cross-section, and no significant dilution of the titanium alloy was observed. These coatings maintain similar bioactivity to that of the precursor material as demonstrated by immersion in simulated body fluid. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. A major advance in powder metallurgy

    Science.gov (United States)

    Williams, Brian E.; Stiglich, Jacob J., Jr.; Kaplan, Richard B.; Tuffias, Robert H.

    1991-01-01

    Ultramet has developed a process which promises to significantly increase the mechanical properties of powder metallurgy (PM) parts. Current PM technology uses mixed powders of various constituents prior to compaction. The homogeneity and flaw distribution in PM parts depends on the uniformity of mixing and the maintenance of uniformity during compaction. Conventional PM fabrication processes typically result in non-uniform distribution of the matrix, flaw generation due to particle-particle contact when one of the constituents is a brittle material, and grain growth caused by high temperature, long duration compaction processes. Additionally, a significant amount of matrix material is usually necessary to fill voids and create 100 percent dense parts. In Ultramet's process, each individual particle is coated with the matrix material, and compaction is performed by solid state processing. In this program, Ultramet coated 12-micron tungsten particles with approximately 5 wt percent nickel/iron. After compaction, flexure strengths were measured 50 percent higher than those achieved in conventional liquid phase sintered parts (10 wt percent Ni/Fe). Further results and other material combinations are discussed.

  18. Method to blend separator powders

    Science.gov (United States)

    Guidotti, Ronald A.; Andazola, Arthur H.; Reinhardt, Frederick W.

    2007-12-04

    A method for making a blended powder mixture, whereby two or more powders are mixed in a container with a liquid selected from nitrogen or short-chain alcohols, where at least one of the powders has an angle of repose greater than approximately 50 degrees. The method is useful in preparing blended powders of Li halides and MgO for use in the preparation of thermal battery separators.

  19. Fluoropolymer - TiO2 coatings and their superhydrophilicity

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob; Jepsen, Henrik

    In this work the superhydrophilicity of coatings on fluoropolymer were investigated. The different coatings were prepared by help of P25 Degussa TiO2 powder, titaniumisopropoxide, Lumiflon® and two different curing agents (BL 3175 and Cymel 303). The investigations were performed by help of a sta...

  20. Plasma technology for powder particles

    Energy Technology Data Exchange (ETDEWEB)

    Kranz, E. (Technische Hochschule, Ilmenau (German Democratic Republic))

    1983-03-01

    A survey is given of principles and applications of plasma spraying and of powder transformation and generation in plasma considering spheroidization, grain size transformation, powder particle formation, powder reduction, and melting within the power range of 10/sup 3/ to 10/sup 7/ W. The products are applied in many industrial fields such as nuclear engineering, hard metal production, metallurgy, catalysis, and semiconductor techniques.

  1. Application of Coating Technology for Accident Tolerant Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Gil; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jeong-Yong; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    To commercialize the ATF cladding concepts, various factors are considered, such as safety under normal and accident conditions, economy for the fuel cycle, and developing development challenges, and schedule. From the proposed concepts, it is known that the cladding coating, FeCrAl alloy, and Zr-Mo claddings are considered as a near/mid-term application, whereas the SiC material is considered as a long-term application. Among them, the benefit of cladding coating on Zr-based alloys is the fuel cycle economy regarding the manufacturing, neutron cross section, and high tritium permeation characteristics. However, the challenge of cladding coating on Zr-based alloys is the lower oxidation resistance and mechanical strength at high-temperature than other concepts. Another important point is the adhesion property between the Zr-based alloy and coating materials. As an improved coating technology compared to a previous study, a 3D laser coating technology supplied with Cr powders is considered to make a coated cladding because it is possible to make a coated layer on the tubular cladding surface by controlling the 3-diminational axis. We are systematically studying the laser beam power, inert gas flow, cooling of the cladding tube, and powder control as key points to develop 3D laser coating technology. After Cr-coating on the Zr-based cladding, ring compression and ring tensile tests were performed to evaluate the adhesion property between a coated layer and Zr-based alloy tube at room temperature (RT), and a high-temperature oxidation test was conducted to evaluate the oxidation behavior at 1200 .deg. C of the coated tube samples. A 3D laser coating method supplied with Cr powders was developed to decrease the high-temperature oxidation rate in a steam environment through a systematic study for various coating parameters, and a Cr-coated Zircaloy-4 cladding tube of 100 mm in length to the axial direction can be successfully manufactured.

  2. Gas-Phase Combustion Synthesis of Aluminum Nitride Powder

    Science.gov (United States)

    Axelbaum, R. L.; Lottes, C. R.; Huertas, J. I.; Rosen, L. J.

    1996-01-01

    Due to its combined properties of high electrical resistivity and high thermal conductivity aluminum nitride (AlN) is a highly desirable material for electronics applications. Methods are being sought for synthesis of unagglomerated, nanometer-sized powders of this material, prepared in such a way that they can be consolidated into solid compacts having minimal oxygen content. A procedure for synthesizing these powders through gas-phase combustion is described. This novel approach involves reacting AlCl3, NH3, and Na vapors. Equilibrium thermodynamic calculations show that 100% yields can be obtained for these reactants with the products being AlN, NaCl, and H2. The NaCl by-product is used to coat the AlN particles in situ. The coating allows for control of AlN agglomeration and protects the powders from hydrolysis during post-flame handling. On the basis of thermodynamic and kinetic considerations, two different approaches were employed to produce the powder, in co-flow diffusion flame configurations. In the first approach, the three reactants were supplied in separate streams. In the second, the AlCl3 and NH3 were premixed with HCl and then reacted with Na vapor. X-ray diffraction (XRD) spectra of as-produced powders show only NaCl for the first case and NaCl and AlN for the second. After annealing at 775 C tinder dynamic vacuum, the salt was removed and XRD spectra of powders from both approaches show only AlN. Aluminum metal was also produced in the co-flow flame by reacting AlCl3 with Na. XRD spectra of as-produced powders show the products to be only NaCl and elemental aluminum.

  3. Synthesis of Uranium nitride powders using metal uranium powders

    International Nuclear Information System (INIS)

    Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik

    2012-01-01

    Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N 15 gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work

  4. Dispersing powders in liquids

    CERN Document Server

    Nelson, RD

    1988-01-01

    This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica

  5. Laser cladding of wear resistant metal matrix composite coatings

    International Nuclear Information System (INIS)

    Yakovlev, A.; Bertrand, Ph.; Smurov, I.

    2004-01-01

    A number of coatings with wear-resistant properties as well as with a low friction coefficient are produced by laser cladding. The structure of these coatings is determined by required performance and realized as metal matrix composite (MMC), where solid lubricant serves as a ductile matrix (e.g. CuSn), reinforced by appropriate ceramic phase (e.g. WC/Co). One of the engineered coating with functionally graded material (FGM) structure has a dry friction coefficient 0.12. Coatings were produced by coaxial injection of powder blend into the zone of laser beam action. Metallographic and tribological examinations were carried out confirming the advanced performance of engineered coatings

  6. Container for nuclear fuel powders

    International Nuclear Information System (INIS)

    Etheredge, B.F.; Larson, R.I.

    1982-01-01

    A critically safe container is disclosed for the storage and rapid discharge of enriched nuclear fuel material in powder form is disclosed. The container has a hollow, slab-shaped container body that has one critically safe dimension. A powder inlet is provided on one side wall of the body adjacent to a corner thereof and a powder discharge port is provided at another corner of the body approximately diagonal the powder inlet. Gas plenum for moving the powder during discharge are located along the side walls of the container adjacent the discharge port

  7. Recycled hydroxyapatite coatings on 316L stainless steel substrates

    International Nuclear Information System (INIS)

    Mendes Filho, Antonio Alves; Pereira, Renato Alves; Araujo, Fernando Gabriel da Silva; Sousa, Camila Mateus de

    2010-01-01

    In this work were evaluated recycled hydroxyapatite coatings on 316L stainless steel substrates by plasma thermal aspersion. The hydroxyapatite used was obtained from bovine bone by the hydrothermal method. The samples of hydroxyapatite powders were divided according to their particle size distribution. The adhesion of the powders coating to the substrate was evaluated by assay scratch. The X-ray diffraction techniques and scanning electron microscopy were also used. The results of scratch resistance were between 46N and 63N. Analysis by scanning electron microscopy and x-ray diffraction showed no cracks coatings, single-phase and with few fused particles. (author)

  8. Laser cladding of Zr-based coating on AZ91D magnesium alloy for ...

    Indian Academy of Sciences (India)

    based coating made of Zr powder was fabricated on AZ91D magnesium alloy by laser cladding. The microstructure of the coating was characterized by XRD, SEM and TEM techniques. The wear resistance of the coating was evaluated under dry ...

  9. MICROSTRUCTURE OF CR2O3 COATINGS ON STEEL AND THE EFFECT OF SILICON

    NARCIS (Netherlands)

    VANDENBURG, M; DEHOSSON, JTM; Burg, M. van den

    This paper concentrates on the microstructural features of steel containing 22 wt.% Cr, coated with Cr2O3 by laser processing. It turned out that after laser coating the Cr2O3 powder has completely transformed to Fe0.3Cr2.7O4 having the tetragonal distorted spinel structure. Dispersed in the coating

  10. Design and performance evaluation of the functional coating for air purification under indoor conditions

    NARCIS (Netherlands)

    Lorencik, S.; Yu, Q.L.; Brouwers, H.J.H.

    2015-01-01

    The present work aims to develop a photocatalytic coating for the improvement of indoor air quality. Two types of visible-light responsive photocatalysts (powder and suspension form) were applied into a water-based acrylic coating. The applied materials were characterized and the developed coatings

  11. Nickel and titanium nanoboride composite coating

    International Nuclear Information System (INIS)

    Efimova, K A; Galevsky, G V; Rudneva, V V; Kozyrev, N A; Orshanskaya, E G

    2015-01-01

    Electrodeposition conditions, structural-physical and mechanical properties (microhardness, cohesion with a base, wear resistance, corrosion currents) of electroplated composite coatings on the base of nickel with nano and micro-powders of titanium boride are investigated. It has been found out that electro-crystallization of nickel with boride nanoparticles is the cause of coating formation with structural fragments of small sizes, low porosity and improved physical and mechanical properties. Titanium nano-boride is a component of composite coating, as well as an effective modifier of nickel matrix. Nano-boride of the electrolyte improves efficiency of the latter due to increased permissible upper limit of the cathodic current density. (paper)

  12. Preparation of superconductor precursor powders

    Science.gov (United States)

    Bhattacharya, Raghunath

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  13. Microscopic analysis of nanostructured plasma coatings

    Science.gov (United States)

    Ageev, E. V.; Altukhov, A. Yu; Ageeva, E. V.; Khardikov, S. V.

    2018-03-01

    In the course of the study, it was found that plasma nanocomposite coating obtained from a mixture of powders of BRS, VK8 and nichrome with a portable plasma device “ALPES-02M” has high performance properties, which significantly expands the scope of its application.

  14. Study on Metal Microfilter Coated with Ceramics by Using Plasma Thermal Spray Method

    International Nuclear Information System (INIS)

    Song, In Gyu; Shin, Hyun Myung; Choi, Hae Woon; Lee, Young Min

    2011-01-01

    This research was performed on a microfilter made of a hybrid material (ceramic + metal) that was coated with ceramics on the metal-filter surface by using the thermal spray method. The ceramic powders used were Al 2 O 3 +40TiO 2 powder with a particle size of 20 μm and Al 2 O 3 (98%+)powder with a particle size of 45 μm. The metal filters were filter-grade 20 μm, 30 μm, and 50 μm sintered metal powder filters (SIKA-R 20 IS, 30 IS, 50 IS: Sinter Metals Filters) and filter-grade 75 μm sintered mesh filter with five layers. Ceramic-coated filters that were coated using the thermal spray method had a great influence on powder material, particle size, and coating thickness. However, these filters showed a fine performance when used as micro-filters

  15. Correlation of microstructure and wear resistance of molybdenum blend coatings fabricated by atmospheric plasma spraying

    International Nuclear Information System (INIS)

    Hwang, Byoungchul; Lee, Sunghak; Ahn, Jeehoon

    2004-01-01

    The correlation of microstructure and wear resistance of various molybdenum blend coatings applicable to automotive parts was investigated in this study. Five types of spray powders, one of which was pure molybdenum powder and the others were blends of brass, bronze, and aluminum alloy powders with molybdenum powder, were deposited on a low-carbon steel substrate by atmospheric plasma spraying (APS). Microstructural analysis of the coatings showed that they consisted of a curved lamellar structure formed by elongated splats, with hard phases that formed during spraying being homogeneously distributed in the molybdenum matrix. The wear test results revealed that the blend coatings showed better wear resistance than the pure molybdenum coating because they contained a number of hard phases. In particular, the molybdenum coating blended with bronze and aluminum alloy powders and the counterpart material showed an excellent wear resistance due to the presence of hard phases, such as CuAl 2 and Cu 9 Al 4 . In order to improve overall wear properties for the coating and the counterpart material, appropriate spray powders should be blended with molybdenum powders to form hard phases in the coatings

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2011-11-01

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

  18. Diffraction. Powder, amorphous, liquid

    International Nuclear Information System (INIS)

    Sosnowska, I.M.

    1999-01-01

    Neutron powder diffraction is a unique tool to observe all possible diffraction effects appearing in crystal. High-resolution neutron diffractometers have to be used in this study. Analysis of the magnetic structure of polycrystalline materials requires the use of high-resolution neutron diffraction in the range of large interplanar distances. As distinguished from the double axis diffractometers (DAS), which show high resolution only at small interplanar distances, TOF (time-of-flight) diffractometry offers the best resolution at large interplanar distances. (K.A.)

  19. LARC powder prepreg system

    Science.gov (United States)

    Baucom, Robert M.; Marchello, Joseph M.

    1990-01-01

    Thermoplastic prepregs of LARC-TPI have been produced in a fluidized bed unit on spread continuous fiber tows. The powders are melted on the fibers by radiant heating to adhere the polymer to the fiber. This process produces tow prepreg uniformly without imposing severe stress on the fibers or requiring long high temperature residence times for the polymer. Unit design theory and operating correlations have been developed to provide the basis for scale up to commercial operation. Special features of the operation are the pneumatic tow spreader, fluidized bed and resin feed systems.

  20. Novel Fe-based nanocrystalline powder cores with excellent magnetic properties produced using gas-atomized powder

    Science.gov (United States)

    Chang, Liang; Xie, Lei; Liu, Min; Li, Qiang; Dong, Yaqiang; Chang, Chuntao; Wang, Xin-Min; Inoue, Akihisa

    2018-04-01

    FeSiBPNbCu nanocrystalline powder cores (NPCs) with excellent magnetic properties were fabricated by cold-compaction of the gas-atomized amorphous powder. Upon annealing at the optimum temperature, the NPCs showed excellent magnetic properties, including high initial permeability of 88, high frequency stability up to 1 MHz with a constant value of 85, low core loss of 265 mW/cm3 at 100 kHz for Bm = 0.05 T, and superior DC-bias permeability of 60% at a bias field of 100 Oe. The excellent magnetic properties of the present NPCs could be attributed to the ultrafine α-Fe(Si) phase precipitated in the amorphous matrix and the use of gas-atomized powder coated with a uniform insulation layer.

  1. Computational Simulation on a Coaxial Substream Powder Feeding Laval Nozzle of Cold Spraying

    Directory of Open Access Journals (Sweden)

    Guosheng HUANG

    2014-09-01

    Full Text Available In this paper, a substream coaxial powder feeding nozzle was investigated for use in cold spraying. The relationship between nozzle structure and gas flow, the acceleration behavior of copper particles were examined by computational simulation method. Also, one of the nozzle was used to spray copper coating on steel substrate. The simulation results indicate that: the velocity of gas at the center of the nozzle is lower than that of the conventional nozzle. Powders are well restrained near the central line of the nozzle, no collision occurred between the nozzle wall and the powders. This type of nozzle with expansion 3.25 can successfully deposit copper coating on steel substrate, the copper coating has low porosity about 3.1 % – 3.8 % and high bonding strength about 23.5 MPa – 26.8 MPa. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4244

  2. Plasma sprayed coatings on crankshaft used steels

    Science.gov (United States)

    Mahu, G.; Munteanu, C.; Istrate, B.; Benchea, M.

    2017-08-01

    Plasma spray coatings may be an alternative to conventional heat treatment of main journals and crankpins of the crankshaft. The applications of plasma coatings are various and present multiple advantages compared to electric arc wire spraying or flame spraying. The study examines the layers sprayed with the following powders: Cr3C2- 25(Ni 20Cr), Al2O3- 13TiO2, Cr2O3-SiO2- TiO2 on the surface of steels used in the construction of a crankshaft (C45). The plasma spray coatings were made with the Spray wizard 9MCE facility at atmospheric pressure. The samples were analyzed in terms of micro and morphological using optical microscopy, scanning electron microscopy and X-ray diffraction. Wear tests on samples that have undergone simulates extreme working conditions of the crankshafts. In order to emphasize adherence to the base material sprayed layer, were carried out tests of microscratches and micro-indentation. Results have showed a relatively compact morphological aspect given by the successive coatings with splat-like specific structures. Following the microscratch analysis it can be concluded that Al2O3-13TiO2 coating has a higher purpose in terms of hardness compared to Cr3C2-(Ni 20Cr) and Cr2O3-SiO2- TiO2 powders. Thermal coatings of the deposited powders have increased the mechanical properties of the material. The results stand to confirm that plasma sprayed Al2O3-13TiO2 powder is in fact a efficient solution for preventing mechanical wear, even with a faulty lubrication system.

  3. NMR study of nanophase Al/Al-oxide powder and consolidated composites

    International Nuclear Information System (INIS)

    Suits, B.H.; Apte, P.; Wilken, D.E.; Siegel, R.W.

    1994-10-01

    27 Al Nuclear Magnetic Resonance (NMR) measurements from aluminum powders and consolidated nanophase aluminum made from those powders are presented. The signals from the metal and surface oxidation are easily separated and are compared before and after consolidation. The results presented indicate that the oxide coating becomes the interface region within the nanophase composite material and that during consolidation the metal has undergone a deformation equivalent to that seen for bulk material under a compressive strain of between 4% and 8%

  4. Investigation of a thermoplastic-powder metallurgy process for the fabrication of porous niobium rods

    International Nuclear Information System (INIS)

    Nordin, D.R.

    1978-06-01

    The feasibility of using a thermoplastic-powder metallurgy technique for the fabrication of porous niobium rods was investigated. Some early problems were overcome to successfully extrude the polymer coated niobium powder into long lengths. The effects of certain process variables were investigated. Residual porosity and extrusion pressure were found to be regulated by the polymer fraction. The procedures for taking the extruded polystyrene--niobium rods through the heat treatments to the final, tin infiltrated stage are explained

  5. Nano-scale analysis of titanium dioxide fingerprint-development powders

    International Nuclear Information System (INIS)

    Reynolds, A J; Jones, B J; Sears, V; Bowman, V

    2008-01-01

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO 2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO 2 particles and efficacy of print development.

  6. Multi-Layered Effects of Fe on EMI Shielding of Sn-Al Hotel Architectural Powder

    Directory of Open Access Journals (Sweden)

    Hung Fei-Shuo

    2016-01-01

    Full Text Available No evident effect in shielding efficiency is observed when the electromagnetic wave-absorbing coating materials were applied in single layers because of the dispersing nature of the powder. When increased to two-layer coating, shielding effects were evident at both high and low frequencies, with greater shielding efficiency at low frequencies over high frequencies. It is worth noting that when increased to three-layer coating, as the weight percentage of powdered Fe increased from 5% to 8% , the shielding efficiency of the powdered-Fe composite material was raised to −35 dB This shows that, as the weight percentage gets higher, the powder shows the resonance phenomenon of permeability spectrum, and at high frequencies, the electromagnetic wave shielding efficiency of the composite materials were greatly increased. As the weight percentage of the powered Fe were increased to 8% , we were unable to spread the powder evenly in the epoxy because of the dispersing characteristic in the electromagnetic properties of Fe and the anisotropic and heterogeneous nature of a powered composite material. During production, the powder aggregates often resulted in greater heterogeneity in the materials and consequently, lowered shielding efficiency at 3GHz.

  7. Nano-scale analysis of titanium dioxide fingerprint-development powders

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A J; Jones, B J [Experimental Techniques Centre, Brunei University, Kingston Lane, Uxbridge, Middlesex, UB8 3PH (United Kingdom); Sears, V; Bowman, V [Fingerprint and Footwear Forensics, Home Office Scientific Development Branch, Sandridge, St Albans, Hertfordshire, AL4 9HQ (United Kingdom)], E-mail: b.j.jones@physics.org

    2008-08-15

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO{sub 2} particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO{sub 2} particles and efficacy of print development.

  8. Characterisation of Suspension Precipitated Nanocrystalline Hydroxyapatite Powders

    International Nuclear Information System (INIS)

    Mallik, P K; Swain, P.K.; Patnaik, S.C

    2016-01-01

    Hydroxyapatite (HA) is a well-known biomaterial for coating on femoral implants, filling of dental cavity and scaffold for tissue replacement. Hydroxyapatite possess limited load bearing capacity due to their brittleness. In this paper, the synthesis of nanocrystalline hydroxyapatite powders was prepared by dissolving calcium oxide in phosphoric acid, followed by addition of ammonia liquor in a beaker. The prepared solution was stirred by using magnetic stirrer operated at temperature of 80°C for an hour. This leads to the formation of hydroxyapatite precipitate. The precipitate was dried in oven for overnight at 100°C. The dried agglomerated precipitate was calcined at 800°C in conventional furnace for an hour. The influence of calcium oxide concentration and pH on the resulting precipitates was studied using BET, XRD and SEM. As result, a well-defined sub-rounded morphology of powders size of ∼41 nm was obtained with a salt concentration of 0.02 M. Finally, it can be concluded that small changes in the reaction conditions led to large changes in final size, shape and degree of aggregation of the hydroxyapatite particles. (paper)

  9. TOF powder diffractometer on a reactor source

    International Nuclear Information System (INIS)

    Bleif, H.J.; Wechsler, D.; Mezei, F.

    1999-01-01

    Complete text of publication follows. The performance of time-of-flight (TOF) methods on Long Pulse Spallation Sources can be studied at a reactor source. For this purpose a prototype TOF monochromator instrument will be installed at the KFKI reactor in Budapest. The initial setup will be a powder diffractometer with a resolution of δd/d down to 2 x 10 -3 at a wavelength of 1 A. The instrument uses choppers to produce neutron pulses of down to 10 μs FWHM. The optimal neutron source for a chopper instrument is a Long Pulse Spallation Source, but even on a continuous source simulations have shown that this instrument outperforms a conventional crystal monochromator powder diffractometer at high resolution. The main components of the TOF instrument are one double chopper defining the time resolution and two single choppers to select the wavelength range and to prevent frame overlap. For inelastic experiments a further chopper can be added in front of the sample. The neutron guide has a super-mirror coating and a curvature of 3500m. The total flight path is 20m and there are 24 single detectors in backscattering geometry. (author)

  10. Tricky choices in pipe coatings can end with epoxy powder

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, B

    1982-03-01

    A brief overview of the economic and social impact of development of the resources of Newfoundland is presented. Currently, the thrust of governmental efforts is to promote the development of the countries resources in the fields of hydrocarbons, hydroelectric, fish, tourism, etc., rather than to permit exploitation and exportation of these resources. In this development, the past problems of ice-locked harbors is now seen as having been solved. (BLM)

  11. Powder-based synthesis of nanocrystalline material components for structural application. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ilyuschenko, A.F.; Ivashko, V.S.; Okovity, V.A. [Powder Metallurgy Research Inst., Minsk (Belarus)] [and others

    1998-12-01

    Hydroxiapate spray coatings and substrates for implant production as well as multilayered metal ceramic coatings from nanocrystalline materials are a subject of the investigation. The work aims at the improvement of quality of said objects. This study has investigated the processes of hydroxiapatite powder production. Sizes, shapes and relief of initial HA powder surface are analyzed using SEM and TEM. Modes of HA plasma spraying on a substrate from titanium and associated compositions of traditional and nanocrystalline structure are optimized. The quality of the sprayed samples are studied using X-ray phase analysis and metallographic analysis. The results of investigations of bioceramic coating spraying on titanium are theoretically generalized, taking into account obtained experimental data. The results of investigations of ion-beam technology are presented for spraying multilayered coatings consisting of alternating metal-ceramic layers of nanocrystalline structure.

  12. Nuclear fuel powder transfer device

    International Nuclear Information System (INIS)

    Komono, Akira

    1998-01-01

    A pair of parallel rails are laid between a receiving portion to a molding portion of a nuclear fuel powder transfer device. The rails are disposed to the upper portion of a plurality of parallel support columns at the same height. A powder container is disposed while being tilted in the inside of the vessel main body of a transfer device, and rotational shafts equipped with wheels are secured to right and left external walls. A nuclear powder to be mixed, together with additives, is supplied to the powder container of the transfer device. The transfer device engaged with the rails on the receiving side is transferred toward the molding portion. The wheels are rotated along the rails, and the rotational shafts, the vessel main body and the powder container are rotated. The nuclear powder in the tilted powder container disposed is rotated right and left and up and down by the rotation, and the powder is mixed satisfactory when it reaches the molding portion. (I.N.)

  13. Superconductors by powder metallurgy techniques

    International Nuclear Information System (INIS)

    Pickus, M.R.; Wang, J.L.F.

    1976-05-01

    Fabrication methods for Nb 3 Sn type compounds are described. Information is included on the Bell Telephone process, the General Electric tape process, superconductor stability, the bronze process, powder metallurgy multifilamentary tapes and wires, and current assessment of powder metallurgy superconducting wire

  14. Pin Wire Coating Trip Report

    International Nuclear Information System (INIS)

    Spellman, G P

    2004-01-01

    A meeting to discuss the current pin wire coating problems was held at the Reynolds plant in Los Angeles on 2MAR04. The attendance list for Reynolds personnel is attached. there was an initial presentation which gave a brief history and the current status of pin wire coating at Reynolds. There was a presentation by Lori Primus on the requirements and issues for the coating. There was a presentation by Jim Smith of LANL on the chemistry and to some extent process development done to date. There was a long session covering what steps should be taken in the short term and, to a lesser extent, the long term. The coating currently being used is a blend of two polymers, polyethersulfone and polyparabanic acid (PPA) and some TiO2 filler. This system was accepted and put into production when the pin wire coating was outsourced to another company in 1974. When that company no longer was interested, the wire coating was brought in-house to Reynolds. At that time polyparabanic acid was actually a commercial product available from Exxon under the trade name Tradlon. However, it appears that the material used at Reynolds was synthesized locally. Also, it appears that a single large batch was synthesized in that time period and used up to 1997 when the supply ran out. The reason for the inclusion of TiO2 is not known although it does act as a rheological thickener. However, a more controlled thickening can be obtained with materials such as fumed silica. This material would have less likelihood of causing point imperfections in the coatings. Also, the mixing technique being used for all stages of the process is a relatively low shear ball mill process and the author recommends a high shear process such as a three roll paint mill, at least for the final mixing. Since solvent is added to the powder at Reynolds, it may be that they need to have the paint mill there

  15. Hard coatings

    International Nuclear Information System (INIS)

    Dan, J.P.; Boving, H.J.; Hintermann, H.E.

    1993-01-01

    Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many processes have been developed which are variations and/or combinations of the basic CVD and PVD methods. The main difference between these two families of deposition techniques is that the CVD is an elevated temperature process (≥ 700 C), while the PVD on the contrary, is rather a low temperature process (≤ 500 C); this of course influences the choice of substrates and properties of the coating/substrate systems. Fundamental aspects of the vapor phase deposition techniques and some of their influences on coating properties will be discussed, as well as the very important interactions between deposit and substrate: diffusions, internal stress, etc. Advantages and limitations of CVD and PVD respectively will briefly be reviewed and examples of applications of the layers will be given. Parallel to the development and permanent updating of surface modification technologies, an effort was made to create novel characterisation methods. A close look will be given to the coating adherence control by means of the scratch test, at the coating hardness measurement by means of nanoindentation, at the coating wear resistance by means of a pin-on-disc tribometer, and at the surface quality evaluation by Atomic Force Microscopy (AFM). Finally, main important trends will be highlighted. (orig.)

  16. Testing of electroformed deposited iridium/powder metallurgy rhenium rockets

    Science.gov (United States)

    Reed, Brian D.; Dickerson, Robert

    1996-01-01

    High-temperature, oxidation-resistant chamber materials offer the thermal margin for high performance and extended lifetimes for radiation-cooled rockets. Rhenium (Re) coated with iridium (Ir) allow hours of operation at 2200 C on Earth-storable propellants. One process for manufacturing Ir/Re rocket chambers is the fabrication of Re substrates by powder metallurgy (PM) and the application of Ir coatings by using electroformed deposition (ED). ED Ir coatings, however, have been found to be porous and poorly adherent. The integrity of ED Ir coatings could be improved by densification after the electroforming process. This report summarizes the testing of two 22-N, ED Ir/PM Re rocket chambers that were subjected to post-deposition treatments in an effort to densify the Ir coating. One chamber was vacuum annealed, while the other chamber was subjected to hot isostatic pressure (HIP). The chambers were tested on gaseous oxygen/gaseous hydrogen propellants, at mixture ratios that simulated the oxidizing environments of Earth-storable propellants. ne annealed ED Ir/PM Re chamber was tested for a total of 24 firings and 4.58 hr at a mixture ratio of 4.2. After only 9 firings, the annealed ED Ir coating began to blister and spall upstream of the throat. The blistering and spalling were similar to what had been experienced with unannealed, as-deposited ED Ir coatings. The HIP ED Ir/PM Re chamber was tested for a total of 91 firings and 11.45 hr at mixture ratios of 3.2 and 4.2. The HIP ED Ir coating remained adherent to the Re substrate throughout testing; there were no visible signs of coating degradation. Metallography revealed, however, thinning of the HIP Ir coating and occasional pores in the Re layer upstream of the throat. Pinholes in the Ir coating may have provided a path for oxidation of the Re substrate at these locations. The HIP ED Ir coating proved to be more effective than vacuum annealed and as-deposited ED Ir. Further densification is still required to

  17. Review on the Photocatalyst Coatings of TiO2: Fabrication by Mechanical Coating Technique and Its Application

    Directory of Open Access Journals (Sweden)

    Yun Lu

    2015-07-01

    Full Text Available This review presents the latest results of studies directed at photocatalyst coatings of titanium dioxide (TiO2 prepared by mechanical coating technique (MCT and its application. Compared with traditional coating techniques, MCT is a simple, low cost and useful coating formation process, which is proposed and developed based on mechanical frictional wear and impacts between substrate materials and metal powder particles in the bowl of planetary ball mill. The formation process of the metal coatings in MCT includes four stages: The nucleation by adhesion, the formation and coalescence of discrete islands, formation and thickening of continuous coatings, exfoliation of continuous coatings. Further, two-step MCT was developed based on the MCT concept for preparing composite coatings on alumina (Al2O3 balls. This review also discusses the influence on the fabrication of photocatalyst coatings after MCT and improvement of its photocatalytic activity: oxidation conditions, coating materials, melt salt treatment. In this review, the oxidation conditions had been studied on the oxidation temperature of 573 K, 673 K, 773 K, 873 K, 973 K, 1173 K and 1273 K, the oxidation time of 0.5 h, 1 h, 3 h, 10 h, 15 h, 20 h, 30 h, 40 h, and 50 h. The photocatalyst coatings showed the highest photocatalytic activity with the oxidation condition of 1073 K for 15 h. The metal powder of Ti, Ni and Cr had been used as the coating materials. The composite metal powder could affect the surface structure and photocatalytic activity. On the other hand, the melt salt treatment with KNO3 is an effective method to form the nano-size structure and enhance photocatalytic activity, especially under visible light.

  18. 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.

  19. Light extinction in metallic powder beds: Correlation with powder structure

    International Nuclear Information System (INIS)

    Rombouts, M.; Froyen, L.; Gusarov, A.V.; Bentefour, E.H.; Glorieux, C.

    2005-01-01

    A theoretical correlation between the effective extinction coefficient, the specific surface area, and the chord length distribution of powder beds is verified experimentally. The investigated powder beds consist of metallic particles of several tens of microns. The effective extinction coefficients are measured by a light-transmission technique at a wavelength of 540 nm. The powder structure is characterized by a quantitative image analysis of powder bed cross sections resulting in two-point correlation functions and chord length distributions. The specific surface area of the powders is estimated by laser-diffraction particle-size analysis and by the two-point correlation function. The theoretically predicted tendency of increasing extinction coefficient with specific surface area per unit void volume is confirmed by the experiments. However, a significant quantitative discrepancy is found for several powders. No clear correlation of the extinction coefficient with the powder material and particle size, and morphology is revealed, which is in line with the assumption of geometrical optics

  20. Testing of Flame Sprayed Al2O3 Matrix Coatings Containing TiO2

    Directory of Open Access Journals (Sweden)

    Czupryński A.

    2016-09-01

    Full Text Available The paper presents the results of the properties of flame sprayed ceramic coatings using oxide ceramic materials coating of a powdered aluminium oxide (Al2O3 matrix with 3% titanium oxide (TiO2 applied to unalloyed S235JR grade structural steel. A primer consisting of a metallic Ni-Al-Mo based powder has been applied to plates with dimensions of 5×200×300 mm and front surfaces of Ø40×50 mm cylinders. Flame spraying of primer coating was made using a RotoTec 80 torch, and an external coating was made with a CastoDyn DS 8000 torch. Evaluation of the coating properties was conducted using metallographic testing, phase composition research, measurement of microhardness, substrate coating adhesion (acc. to EN 582:1996 standard, erosion wear resistance (acc. to ASTM G76-95 standard, and abrasive wear resistance (acc. to ASTM G65 standard and thermal impact. The testing performed has demonstrated that flame spraying with 97% Al2O3 powder containing 3% TiO2 performed in a range of parameters allows for obtaining high-quality ceramic coatings with thickness up to ca. 500 µm on a steel base. Spray coating possesses a structure consisting mainly of aluminium oxide and a small amount of NiAl10O16 and NiAl32O49 phases. The bonding primer coat sprayed with the Ni-Al-Mo powder to the steel substrate and external coating sprayed with the 97% Al2O3 powder with 3% TiO2 addition demonstrates mechanical bonding characteristics. The coating is characterized by a high adhesion to the base amounting to 6.5 MPa. Average hardness of the external coating is ca. 780 HV. The obtained coatings are characterized by high erosion and abrasive wear resistance and the resistance to effects of cyclic thermal shock.

  1. Microstructural and mechanical evaluation of laser-assisted cold sprayed bio-ceramic coatings: potential use for biomedical applications

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-02-01

    Full Text Available Bio-composite coatings of 20 wt.%, HAP and 80 wt.%, HAP were synthesized on Ti-6Al-4V substrates using LACS technique. The coatings were produced with a laser power of 2.5 kW, powder-laser spot trailing by 5 s. The coatings were analyzed...

  2. Preparation and Properties of Polyester-Based Nanocomposite Gel Coat System

    Directory of Open Access Journals (Sweden)

    P. Jawahar

    2006-01-01

    Full Text Available Nanocomposite gel coat system is prepared using unsaturated polyester resin with aerosil powder, CaCO3, and organoclay. The influence of organoclay addition on mechanical and water barrier properties of gel coat system is studied for different amount (1, 2, and 3 wt % of organoclay. The nanolevel incorporation of organoclay improves the mechanical and water barrier properties of nanocomposite gel coat system. The nanocomposite gel coat system exhibits 55% improvement in tensile modulus and 25% improvement in flexural modulus. There is a 30% improvement in impact property of nanocomposite gel coat system. The dynamic mechanical analysis shows a slight increase in glass transition temperature for nanocomposite gel coat system.

  3. Protective Coatings

    Science.gov (United States)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  4. Black powder in gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Sherik, Abdelmounam [Saudi Aramco, Dhahran (Saudi Arabia)

    2009-07-01

    Despite its common occurrence in the gas industry, black powder is a problem that is not well understood across the industry, in terms of its chemical and physical properties, source, formation, prevention or management of its impacts. In order to prevent or effectively manage the impacts of black powder, it is essential to have knowledge of its chemical and physical properties, formation mechanisms and sources. The present paper is divided into three parts. The first part of this paper is a synopsis of published literature. The second part reviews the recent laboratory and field work conducted at Saudi Aramco Research and Development Center to determine the compositions, properties, sources and formation mechanisms of black powder in gas transmission systems. Microhardness, nano-indentation, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) techniques were used to analyze a large number of black powder samples collected from the field. Our findings showed that black powder is generated inside pipelines due to internal corrosion and that the composition of black powder is dependent on the composition of transported gas. The final part presents a summary and brief discussion of various black powder management methods. (author)

  5. Hardness and Elastic Modulus of Titanium Nitride Coatings Prepared by Pirac Method

    Science.gov (United States)

    Wu, Siyuan; Wu, Shoujun; Zhang, Guoyun; Zhang, Weiguo

    In the present work, hardness and elastic modulus of a titanium nitride coatings prepared on Ti6Al4V by powder immersion reaction-assisted coating (PIRAC) are tested and comparatively studied with a physical vapor deposition (PVD) TiN coating. Surface hardness of the PIRAC coatings is about 11GPa, much lower than that of PVD coating of 22GPa. The hardness distribution profile from surface to substrate of the PVD coatings is steeply decreased from ˜22GPa to ˜4.5GPa of the Ti6Al4V substrate. The PIRAC coatings show a gradually decreasing hardness distribution profile. Elastic modulus of the PVD coating is about 426GPa. The PIRAC coatings show adjustable elastic modulus. Elastic modulus of the PIRAC coatings prepared at 750∘C for 24h and that at 800∘C for 8h is about 234 and 293GPa, respectively.

  6. (TECTONA GRANDIS LEAF POWDER

    Directory of Open Access Journals (Sweden)

    Yash Mishra

    2015-01-01

    Full Text Available In this study, the adsorption potential of Teak (Tectona grandis leaf powder (TLP toremove Methylene blue (MB and Malachite Green (MG dye molecules from aqueoussolution was investigated. Batch experiments were conducted to evaluate the influenceof operational parameters such as, pH (2−9, adsorbent dosage (1−7 g/L, contact time(15−150 minutes and initial dye concentration (20−120 mg/L at stirring speed of 150rpm for the adsorption of MB and MG on TLP. Maximum removal efficiency of 98.4%and 95.1% was achieved for MB and MG dye, respectively. The experimentalequilibrium data were analysed using Langmuir, Freundlich and Temkin isothermmodels and it was found that, it fitted well to the Freundlich isotherm model. Thesurface structure and morphology of the adsorbent was characterized using scanningelectron microscopy (SEM and the presence of functional groups and its interactionwith the dye molecules were analysed using Fourier transform infrared spectroscopy(FTIR. Based on the investigation, it has been demonstrated that the teak leaf powderhas good potential for effective adsorption of methylene blue and malachite green dye.

  7. Low pressure powder injection moulding of stainless steel powders

    Energy Technology Data Exchange (ETDEWEB)

    Zampieron, J.V.; Soares, J.P.; Mathias, F.; Rossi, J.L. [Powder Processing Center CCP, Inst. de Pesquisas Energeticas e Nucleares, Sao Paulo, SP (Brazil); Filho, F.A. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

    2001-07-01

    Low-pressure powder injection moulding was used to obtain AISI 316L stainless steel parts. A rheological study was undertaken using gas-atomised powders and binders. The binders used were based on carnauba wax, paraffin, low density polyethylene and microcrystalline wax. The metal powders were characterised in terms of morphology, particle size distribution and specific surface area. These results were correlated to the rheological behaviour. The mixture was injected in the shape of square bar specimens to evaluate the performance of the injection process in the green state, and after sintering. The parameters such as injection pressure, viscosity and temperature were analysed for process optimisation. The binders were thermally removed in low vacuum with the assistance of alumina powders. Debinding and sintering were performed in a single step. This procedure shortened considerably the debinding and sintering time. (orig.)

  8. Characteristics and heat treatment of cold-sprayed Al-Sn binary alloy coatings

    International Nuclear Information System (INIS)

    Ning, Xian-Jin; Kim, Jin-Hong; Kim, Hyung-Jun; Lee, Changhee

    2009-01-01

    In this study, Al-Sn binary alloy coatings were prepared with Al-5 wt.% Sn (Al-5Sn) and Al-10 wt.% Sn (Al-10Sn) gas atomized powders by low pressure and high pressure cold spray process. The microstructure and microhardness of the coatings were characterized. To understand the coarsening of tin in the coating, the as-sprayed coatings were annealed at 150, 200, 250 and 300 o C for 1 h, respectively. The effect of annealing on microstructure and the bond strength of the coatings were investigated. The results show that Al-5Sn coating can be deposited by high pressure cold spray with nitrogen while Al-10Sn can only be deposited by low pressure cold spray with helium gas. Both Al-5Sn and Al-10Sn coatings present dense structures. The fraction of Sn in as-sprayed coatings is consistent with that in feed stock powders. The coarsening and/or migration of Sn phase in the coatings were observed when the annealing temperature exceeds 200 deg. C. Furthermore, the microhardness of the coatings decreased significantly at the annealing temperature of 250 deg. C. EDXA analysis shows that the heat treatment has no significant effect on fraction of Sn phase in Al-5Sn coatings. Bonding strength of as-sprayed Al-10Sn coating is slightly higher than that of Al-5Sn coating. Annealing at 200 o C can increase the bonding strength of Al-5Sn coatings.

  9. Effect of Ni content on microwave absorbing properties of MnAl powder

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen-zhong; Lin, Pei-hao, E-mail: gllph2002@163.com; Huang, Wei-chao; Pan, Shun-kang; Liu, Ye; Wang, Lei

    2016-09-01

    MnAlNi powder was prepared by the process of vacuum levitation melting and high-energy ball milling, The morphology and phase structure of the powder were analyzed by Scanning Electron Microscope(SEM), X-ray diffraction(XRD) and the effect of the Ni content on microwave absorbing properties of MnAl powder was investigated by an vector network analyzer. The addition of Ni, which improved the microwave absorbing properties of MnAl powder but not changed the composition of Al{sub 8}Mn{sub 5} alloy. The minimum reflectivity of (Al{sub 8}Mn{sub 5}){sub 0.95}Ni{sub 0.05} powder with a coating thickness (d) of 1.8 mm was about −40.8 dB and has better bandwidth effect, the absorbing mechanism of AlMnNi powders on the electromagnetic was related to the electromagnetic loss within the absorbing coatings and the effect of coating thickness on the interference loss of electromagnetic wave. - Highlights: • The grain size and cell volume of Al{sub 8}Mn{sub 5} alloy phase were decreased with the increasing of Ni. • ε″ and μ″ of powder moves toward low frequency region at the beginning then moves high. • The minimum reflectivity of (Al{sub 8}Mn{sub 5}){sub 0.95}Ni{sub 0.05} powder was −40.8 dB with 1.8 mm thickness. • The lowest reflection loss peak of (Al{sub 8}Mn{sub 5}){sub 0.95}Ni{sub 0.05} was −46.3 dB with 2.2 mm thickness.

  10. Shock compaction of molybdenum powder

    Science.gov (United States)

    Ahrens, T. J.; Kostka, D.; Vreeland, T., Jr.; Schwarz, R. B.; Kasiraj, P.

    1983-01-01

    Shock recovery experiments which were carried out in the 9 to 12 GPa range on 1.4 distension Mo and appear adequate to compact to full density ( 45 (SIGMA)m) powders were examined. The stress levels, however, are below those calculated to be from 100 to approx. 22 GPa which a frictional heating model predicts are required to consolidate approx. 10 to 50 (SIGMA)m particles. The model predicts that powders that have a distension of m=1.6 shock pressures of 14 to 72 GPa are required to consolidate Mo powders in the 50 to 10 (SIGMA)m range.

  11. A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

    International Nuclear Information System (INIS)

    Thakur, Lalit; Arora, Navneet

    2013-01-01

    WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.

  12. A study on erosive wear behavior of HVOF sprayed nanostructured WC-CoCr coatings

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Lalit; Arora, Navneet [Indian Institute of Technology Roorkee, Roorkee (India)

    2013-05-15

    WC-CoCr cermet coatings were deposited on stainless steel substrate using high-velocity oxy-fuel (HVOF) thermal spray process. The coatings were developed with two different thermal spray powders: one has WC grains of conventional micron size and the other is composed of nanosized (near-nanostructured) grains. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control the process parameters that have resulted in quality coatings. Cavitation erosion testing was performed using a vibratory test apparatus based on ASTM standard G32-98. Surface morphology of powders and coatings was examined using the FESEM images, and phase identification was performed by XRD analysis. The erosion behavior of coatings and mechanism of material removal was discussed by examining the microstructure images of worn-out surfaces. WC-CoCr cermet coating deposited with nanosized WC grains exhibited higher cavitation erosion resistance as compared to conventional coating.

  13. Thermal stability of double-ceramic-layer thermal barrier coatings with various coating thickness

    International Nuclear Information System (INIS)

    Dai Hui; Zhong Xinghua; Li Jiayan; Zhang Yanfei; Meng Jian; Cao Xueqiang

    2006-01-01

    Double-ceramic-layer (DCL) coatings with various thickness ratios composed of YSZ (6-8 wt.% Y 2 O 3 + ZrO 2 ) and lanthanum zirconate (LZ, La 2 Zr 2 O 7 ) were produced by the atmospheric plasma spraying. Chemical stability of LZ in contact with YSZ in DCL coatings was investigated by calcining powder blends at different temperatures. No obvious reaction was observed when the calcination temperature was lower than 1250 deg. C, implying that LZ and YSZ had good chemical applicability for producing DCL coating. The thermal cycling test indicate that the cycling lives of the DCL coatings are strongly dependent on the thickness ratio of LZ and YSZ, and the coatings with YSZ thickness between 150 and 200 μm have even longer lives than the single-layer YSZ coating. When the YSZ layer is thinner than 100 μm, the DCL coatings failed in the LZ layer close to the interface of YSZ layer and LZ layer. For the coatings with the YSZ thickness above 150 μm, the failure mainly occurs at the interface of the YSZ layer and the bond coat

  14. An electrothermal chemical technology for thermal spray coatings

    International Nuclear Information System (INIS)

    Wald, S.; Appelbaum, G.; Alimi, R.; Rabani, L.; Zoler, D.; Zhitomirsky, V.; Factor, M.; Roman, I.

    1998-01-01

    A new spray technology for producing hard-coatings, has been developed at the SOREQ Nuclear Research Center. The concept is based on the extensive experience accumulated at SOREQ in the course of the development of Electrothermal (ET), Electrothermal-Chemical (ETC) and Solid-Propellant Electrothermal-Chemical (SPETC) guns(r). High quality coatings may be obtained by thermal spraying powder particles onto a variety of substrates. Mature state-of-the-art technologies such as plasma spray, high velocity oxy fuel (HVOF) and detonation gun (D-Gun) are widely used for many applications. As each method has its own drawbacks there is a need for a combination of several parameters which cannot be achieved by any existing individual commercial technology. The method presented is oriented toward a high-quality, multi-step, high-throughput, easily programmable continuous coating process and relatively inexpensive technology. The combustion products of a solid or liquid propellant accelerate the powder particles of the coating material. A pulsed-plasma jet, provided by a confined capillary discharge, ignites the propellant and controls the combustion process. The powder particles are accelerated to velocities over 1000 m/s. Due to the very high carrier gas density, high velocity, high throughput and high powder consumption efficiency are obtained. The plasma jet enables control of the gas temperature and consequently influences the powder temperature

  15. Scratch induced failure of plasma sprayed alumina based coatings

    International Nuclear Information System (INIS)

    Hazra, S; Bandyopadhyay, P.P.

    2012-01-01

    Highlights: ► Scratch induced failure of alumina based coatings including nanostructured is reported. ► Ceramic is deposited on bond coat instead of steel, emulating a realistic situation. ► Lateral force data is supplemented with microscopy to observe coating failure. ► The failure mechanism during scratching has been identified. ► Critical load of failure has been calculated for each bond-top coat combination. -- Abstract: A set of plasma sprayed coatings were obtained from three alumina based top coat and two bond coat powders. Scratch test was undertaken on these coatings, under constant and linearly varying load. Test results include the lateral force data and scanning electron microscope (SEM) images. Failure occurred by large area spallation of the top coat and in most cases tensile cracks appeared on the exposed bond coat. The lateral force showed an increasing trend with an increase in normal load up to a certain point and beyond this, it assumed a steady average value. The locations of coating spallation and occurrence of maximum lateral force did not coincide. A bond coat did not show a significant role in determining the scratch adhesion strength.

  16. Nanostructured glass–ceramic coatings for orthopaedic applications

    Science.gov (United States)

    Wang, Guocheng; Lu, Zufu; Liu, Xuanyong; Zhou, Xiaming; Ding, Chuanxian; Zreiqat, Hala

    2011-01-01

    Glass–ceramics have attracted much attention in the biomedical field, as they provide great possibilities to manipulate their properties by post-treatments, including strength, degradation rate and coefficient of thermal expansion. In this work, hardystonite (HT; Ca2ZnSi2O7) and sphene (SP; CaTiSiO5) glass–ceramic coatings with nanostructures were prepared by a plasma spray technique using conventional powders. The bonding strength and Vickers hardness for HT and SP coatings are higher than the reported values for plasma-sprayed hydroxyapatite coatings. Both types of coatings release bioactive calcium (Ca) and silicon (Si) ions into the surrounding environment. Mineralization test in cell-free culture medium showed that many mushroom-like Ca and phosphorus compounds formed on the HT coatings after 5 h, suggesting its high acellular mineralization ability. Primary human osteoblasts attach, spread and proliferate well on both types of coatings. Higher proliferation rate was observed on the HT coatings compared with the SP coatings and uncoated Ti-6Al-4V alloy, probably due to the zinc ions released from the HT coatings. Higher expression levels of Runx2, osteopontin and type I collagen were observed on both types of coatings compared with Ti-6Al-4V alloy, possibly due to the Ca and Si released from the coatings. Results of this study point to the potential use of HT and SP coatings for orthopaedic applications. PMID:21292725

  17. Development of Ferrite-Coated Soft Magnetic Composites: Correlation of Microstructure to Magnetic Properties

    Science.gov (United States)

    Sunday, Katie Jo

    Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and boast high melting temperatures, thus providing adequate electrical barriers between metallic particles. These insulating layers are necessary for reducing eddy current losses by increasing resistivity in order to improve the overall magnetic efficiency and subsequent frequency range. The goals of this work are to correlate ferrite-coated Fe powder composites microstructure for the coating and core powder to magnetic properties such as permeability, coercivity, and core loss. We first explore the relevant concepts of SMC materials from their composition to processing steps to pertinent properties. This thesis employs a suite of characterization techniques for powder and composite properties. We use X-ray diffraction, scanning electron microscopy, and transmission electron microscopy to provide a complete understanding of the effect of processing conditions on ferrite-coated Fe-based SMCs. Magnetic, mechanical, and electrical properties are then analyzed to correlate microstructural features and determine their effect on such properties. In the second part of this thesis, we present a proof of concept study on Al2O3- and Al2O3- Fe3O4-coated Fe powder composites, illustrating magnetization is highly dependent on ferromagnetic volume. We then expand on previous work to compare an ideal, crystalline state using Fe3O 4-Fe thin film heterostructures to a highly strained state using bulk powder studies. Fe3O4-coated Fe composites are produced via mechanical

  18. Preparation and properties of silicone fouling release coatings with long-life afterglow fluorescent

    Directory of Open Access Journals (Sweden)

    Zhang Zhanping

    2017-01-01

    Full Text Available Based on polydimethylsiloxane, three-component coatings were prepared with different content of luminescence powder. The results showed that the illuminance of coatings increases with the content of luminescence powder, decays exponentially with the afterglow time, increases exponentially with the increase of exposure time. The afterglow illuminance augments with irradiated light illuminance. All coatings are hydrophobic and oleophilic. Surface free energy decreases with the increase of luminescence powder. They have highest impact-resistance and bend flexibility. The luminescence powder does not change obviously the shore hardness, tensile breaking strength, breaking elongation rate, elastic modular and roughness of coatings. The static test panels in sea generally could be covered obviously by biofouling including sponges, bryophytes and mussels, hydra, kelp, green algae after 2 months of immersion during growing season. But it never found that the barnacle attached on the coating surface during 4 years of immersion test. The static anti-fouling ability of the coatings is very limited. In addition, the sea creatures attached on the coating surface can be easily removed; even attached organisms will fall off and expose again the smooth coating surface. Consequently, all coatings with long-life afterglow fluorescent have a significant effect on preventing adhesion of barnacle and fouling-release performance.

  19. Method of making highly sinterable lanthanum chromite powder

    Science.gov (United States)

    Richards, Von L.; Singhal, Subhash C.

    1992-01-01

    A highly sinterable powder consisting essentially of LaCrO.sub.3, containing from 5 weight % to 20 weight % of a chromite of dopant Ca, Sr, Co, Ba, or Mg and a coating of a chromate of dopant Ca, Sr, Co, Ba, or Mg; is made by (1) forming a solution of La, Cr, and dopant; (2) heating their solutions; (3) forming a combined solution having a desired ratio of La, Cr, and dopant and heating to reduce solvent; (4) forming a foamed mass under vacuum; (5) burning off organic components and forming a charred material; (6) grinding the charred material; (7) heating the char at from 590.degree. C. to 950 C. in inert gas containing up to 50,000 ppm O.sub.2 to provide high specific surface area particles; (8) adding that material to a mixture of a nitrate of Cr and dopant to form a slurry; (9) grinding the particles in the slurry; (10) freeze or spray drying the slurry to provide a coating of nitrates on the particles; and (11) heating the coated particles to convert the nitrate coating to a chromate coating and provide a highly sinterable material having a high specific surface area of over 7 m.sup.2 /g.

  20. Laser shock wave consolidation of nanodiamond powders on aluminum 319

    Energy Technology Data Exchange (ETDEWEB)

    Molian, Pal [Laboratory for Lasers, MEMS, and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)], E-mail: molian@iastate.edu; Molian, Raathai; Nair, Rajeev [Laboratory for Lasers, MEMS, and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)

    2009-01-01

    A novel coating approach, based on laser shock wave generation, was employed to induce compressive pressures up to 5 GPa and compact nanodiamond (ND) powders (4-8 nm) on aluminum 319 substrate. Raman scattering indicated that the coating consisted of amorphous carbon and nanocrystalline graphite with peaks at 1360 cm{sup -1} and 1600 cm{sup -1} respectively. Scanning electron microscopy revealed a wavy, non-uniform coating with an average thickness of 40 {mu}m and absence of thermal effect on the surrounding material. The phase transition from nanodiamond to other phases of carbon is responsible for the increased coating thickness. Vicker's microhardness test showed hardness in excess of 1000 kg{sub f}/mm{sup 2} (10 GPa) while nanoindentation test indicated much lower hardness in the range of 20 MPa to 2 GPa. Optical surface profilometry traces displayed slightly uneven surfaces compared to the bare aluminum with an average surface roughness (R{sub a}) in the range of 1.5-4 {mu}m depending on the shock wave pressure and type of confining medium. Ball-on-disc tribometer tests showed that the coefficient of friction and wear rate were substantially lower than the smoother, bare aluminum sample. Laser shock wave process has thus aided in the generation of a strong, wear resistant, durable carbon composite coating on aluminum 319 substrate.

  1. Fabrication and evaluation of atmospheric plasma spraying WC-Co-Cu-MoS2 composite coatings

    International Nuclear Information System (INIS)

    Yuan Jianhui; Zhu Yingchun; Zheng Xuebing; Ji Heng; Yang Tao

    2011-01-01

    Research highlights: → Protective WC-Co-based coatings containing solid lubricant Cu and MoS 2 used in wear applications were investigated in this study. → It was found that the MoS 2 composition in the feed powder was kept in WC-Co-Cu-MoS 2 coatings, and the decomposition and decarburization of WC in APS process were improved. → Combining the wear resistance of WC with the lubricating properties of Cu and MoS 2 has an extremely beneficial effect on improving the tribological performance of the resulting coating. - Abstract: Protective WC-Co-based coatings containing solid lubricant Cu and MoS 2 used in wear applications were investigated in this study. These coatings were deposited on mild steel substrates by atmospheric plasma spraying (APS). The feedstock powders were prepared by mechanically mixing the solid lubricant powders and WC-Co powder, followed by sintering and crushing the mixtures to avoid different particle flighting trajectories at plasma. The tribological properties of the coatings against stainless steel balls were examined by ball-on-disk (BOD) tribometer under normal atmospheric condition. The microstructure of the coatings was studied by optical microscope, scanning electron microscope and X-ray diffraction. It was found that the MoS 2 composition in the feed powder was kept in WC-Co-Cu-MoS 2 coatings, and the decomposition and decarburization of WC in APS process were improved, which were attributed to the protection of Cu around them. The friction and wear behaviors of all the WC-Co-Cu-MoS 2 coatings were superior to that of WC-Co coating. Such behavior was associated to different wear mechanisms operating for WC-Co coating and the WC-Co-Cu-MoS 2 coatings.

  2. Ultrasonic wave propagation in powders

    Science.gov (United States)

    Al-Lashi, R. S.; Povey, M. J. W.; Watson, N. J.

    2018-05-01

    Powder clumps (cakes) has a significant effect on the flowability and stability of powders. Powder caking is mainly caused by moisture migration due to wetting and environmental (temperature and humidity) changes. The process of moisture migration caking involves creating liquid bridges between the particles during condensation which subsequently harden to form solid bridges. Therefore, an effective and reliable technique is required to quantitatively and non-invasively monitor caking kinetics and effective stiffness. This paper describes two ultrasonic instruments (ultrasonic velocity pulse and airborne ultrasound systems) that have been used to monitor the caking phenomenon. Also, it discusses the relationship between the ultrasonic velocity and attenuation measurements and tracking caking kinetics and the effective stiffness of powders.

  3. Neutron Powder Diffraction in Sweden

    International Nuclear Information System (INIS)

    Tellgren, R.

    1986-01-01

    Neutron powder diffraction in Sweden has developed around the research reactor R2 in Studsvik. The article describes this facility and presents a historical review of research results obtained. It also gives some ideas of plans for future development

  4. Powder metallurgy - some economic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, M.E.

    1982-01-01

    As a forming process powder metallurgy offers reductions in material and energy consumption. The engineering prerequisites and economics are discussed in relation to several industrial applications including automobile parts. 14 refs.

  5. Powder metallurgy of refractory metals

    International Nuclear Information System (INIS)

    Eck, R.

    1979-01-01

    This paper reports on the powder metallurgical methods for the production of high-melting materials, such as pure metals and their alloys, compound materials with a tungsten base and hard metals from liquid phase sintered carbides. (author)

  6. Pressurized Anneal of Consolidated Powders

    Science.gov (United States)

    Nemir, David Charles (Inventor); Rubio, Edward S. (Inventor); Beck, Jan Bastian (Inventor)

    2017-01-01

    Systems and methods for producing a dense, well bonded solid material from a powder may include consolidating the powder utilizing any suitable consolidation method, such as explosive shockwave consolidation. The systems and methods may also include a post-processing thermal treatment that exploits a mismatch between the coefficients of thermal expansion between the consolidated material and the container. Due to the mismatch in the coefficients, internal pressure on the consolidated material during the heat treatment may be increased.

  7. Adhesion property and high-temperature oxidation behavior of Cr-coated Zircaloy-4 cladding tube prepared by 3D laser coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Gil, E-mail: hgkim@kaeri.re.kr; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jeong-Yong; Koo, Yang-Hyun

    2015-10-15

    A 3D laser coating technology using Cr powder was developed for Zr-based alloys considering parameters such as: the laser beam power, inert gas flow, cooling of Zr-based alloys, and Cr powder control. This technology was then applied to Zr cladding tube samples to study the effect of Cr coating on the high-temperature oxidation of Zr-based alloys in a steam environment of 1200 °C for 2000s. It was revealed that the oxide layer thickness formed on the Cr-coated tube surface was about 25-times lower than that formed on a Zircaloy-4 tube surface. In addition, both the ring compression and the tensile tests were performed to evaluate the adhesion properties of the Cr-coated sample. Although some cracks were formed on the Cr-coated layer, the Cr-coated layer had not peeled off after the two tests.

  8. Investigation of machining damage and tool wear resulting from drilling powder metal aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fell, H.A. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)

    1997-05-01

    This report documents the cutting of aluminum powder metallurgy (PM) parts for the North Carolina Manufacturing Extension Partnership. The parts, an aluminum powder metal formulation, were supplied by Sinter Metals Inc., of Conover, North Carolina. The intended use of the alloy is for automotive components. Machining tests were conducted at Y-12 in the machine shop of the Skills Demonstration Center in Building 9737. Testing was done on June 2 and June 3, 1997. The powder metal alloy tested is very abrasive and tends to wear craters and produce erosion effects on the chip washed face of the drills used. It also resulted in huge amounts of flank wear and degraded performance on the part of most drills. Anti-wear coatings on drills seemed to have an effect. Drills with the coating showed less wear for the same amount of cutting. The usefulness of coolants and lubricants in reducing tool wear and chipping/breakout was not investigated.

  9. Passivation process for superfine aluminum powders obtained by electrical explosion of wires

    International Nuclear Information System (INIS)

    Kwon, Young-Soon; Gromov, Alexander A.; Ilyin, Alexander P.; Rim, Geun-Hie

    2003-01-01

    The process of passivation of superfine aluminum powders (SFAPs) (a s ≤100 nm), obtained with the electrical explosion of wires (EEW) method, has been studied. The passivation coatings of different nature (oxides, stearic acid and aluminum diboride) were covered on the particle surface. The process of passivation and analysis of passivated powders was studied by X-ray photoelectron spectroscopy (XPS), XRD, TEM, infrared spectroscopy (IR), mass spectrometry (MS), thermocouple method and bomb calorimetry. After the comprehensive testing of coatings, a model of stabilization of the superfine aluminum particles was suggested, explaining the anomalous high content of aluminum metal in the electroexplosive powders. The main characteristic of the model is a formation of charged structures, which prevent metal oxidation

  10. Performance improvement by alumina coatings on Y

    NARCIS (Netherlands)

    Zhou, Z.; Zhou, Nan; Lu, Xiangyang; ten Kate, O.M.; Valdesueiro Gonzalez, D.; van Ommen, J.R.; Hintzen, H.T.J.M.

    2016-01-01

    To improve the thermal stability, Al2O3 has been successfully coated on a Y3Al5O12:Ce3+ (YAG:Ce) phosphor powder host by using the Atomic Layer Deposition (ALD) approach in a fluidized bed reactor. Transmission Electron Microscopy

  11. Structure and friction properties of cermet and oxide explosion coatings

    International Nuclear Information System (INIS)

    RGrigorov, A.I.; Semenov, A.P.; Fed'ko, Yu.P.; Shtejn, L.M.

    1977-01-01

    Conditions have been specified for spraying explosion coatings of cermets over Kh18N10T stainless steel and an aluminum alloy. A mixture of WC and CO powders served as a material for spraying. The method of micro-X-ray spectrum analysis has been used to study the structure of the transition zone between the coating and the substrate and to establish the mechanism responsible for the formation of a cermet layer

  12. Polymer powder adhesion to metallic surface improvement with plasma

    International Nuclear Information System (INIS)

    Hladik, J.; Pichal, J.; Spatenka, P.; Pichal, J.; Spatenka, P.

    2008-01-01

    Useful method for corrosion prevention is coating of a base material with a suitable substance. It performs a barrier between the base material and its environment. Great attractions in this field have found polymers, among them polyethylenes (PE). Due to the low adhesion grade of unmodified polymer powder or granules the application of any modification process increasing the adhesion grade is crucial. At present there is no universal approach to polymer adhesion improvement and there have been employed various quite different techniques. Our research employed the PE adhesion improvement by plasma modification. There were used two plasma reactors - the microwave low pressure reactor and the atmospheric reactor employing dielectric barrier discharge (DBD). The adhesion of the powder was determined by measurement of strength force demanded for displacement of the PE-metal joint

  13. Development of Bioactive Ceramic Coating on Titanium Alloy substrate for Biomedical Application Using Dip Coating Method

    Science.gov (United States)

    Asmawi, R.; Ibrahim, M. H. I.; Amin, A. M.; Mustafa, N.; Noranai, Z.

    2017-08-01

    Bioactive apatite, such as hydroxyapatite ceramic (HA), [Ca10(PO4)6(OH)2] has been extensively investigated for biomedical applications due to its excellent biocompatibility and tissue bioactivity properties. Its bioactivity provides direct bonding to the bone tissue. Because of its similarity in chemical composition to the inorganic matrix of bone, HA is widely used as implant materials for bone. Unfortunately, because of its poor mechanical properties,. this bioactive material is not suitable for load bearing applications. In this study, by the assistance of dip-coating technique, HA coatings were deposited on titanium alloy substrates by employing hydrothermal derived HA powder. The produced coatings then were oven-dried at 130°C for 1 hour and calcined at various temperature over the range of 200-800°C for 1 hour. XRD measurement showed that HA was the only phase present in the coatings. However coatings calcined at 800°C comprised a mixture of HA and tri-calcium phosphate (TCP). FTIR measurement showed the existence of hydroxyl, phosphate, and carbonate bands. PO4 - band became sharper and narrower with the increased of calcination temperature. FESEM observation showed that the coating is polycrystalline with individual particles of nano to submicron size and has an average particle size of 35 nm. The thickness of the coating are direcly propotional with the viscosity of coating slurry. It was shown that the more viscous coating slurry would produce a thicker ceramic coating. Mechanical properties of the coating were measured in term of adhesion strength using a Micro Materials Nano Test microscratch testing machine. The result revealed that the coating had a good adhesion to the titanium alloy substrate.

  14. Hydroxyapatite coatings of fracture fixation plates for orthopedic applications

    International Nuclear Information System (INIS)

    Omar, M.A.; Abdullah, N.S.; Yahya, N.M.; Subuki, I.; Hassan, N.; Mohamad, S.M.

    2007-01-01

    The plasma sprayed hydroxyapatite (HA) coatings are used on metallic implants to improve their adhesion to bone. The present study investigates the plasma sprayed process of HA on the fracture fixation plates fabricated by metal injection moulding process. The phase and microstructure of the coatings were studied and their microhardness measured. The phase composition of coatings was analyzed by the use of X-ray diffraction method. The homogeneity of the deposit and coating thickness were evaluated using scanning electron microscope (SEM). The results suggest that the nature of the coating morphology, phase and crystallinity changes with respect to the plasma sprayed processing parameters. The XRD revealed the presence of both amorphous and crystalline phases. In addition, the powder particles also melt partially in some region and coating microstructure varied from a porous structure to a smooth glassy structure or a typical lamellar structure. (author)

  15. Microstructure and bonding strength of Ni-based alloy coating

    Directory of Open Access Journals (Sweden)

    LIU Qing

    2006-05-01

    Full Text Available A Ni-Cr-B-Si coating technique was developed and successfully applied on austenite grey iron substrate in a conventional resistance furnace under graphite powder protection. The microstructure, phase distribution, chemical composition profile and microhardness along the coating layer depth were investigated. Shear strength of the coating was also tested. Microanalysis shows that the coating is consist of γ-Ni solution and γ-Ni+Ni3B lamellar eutectic, as well as small amount of Cr5B3 particles. Diffusion induced metallurgical bonding occurs at the coating/substrate interfaces, and the higher the temperature, the more sufficient elements diffused, the broader interfusion region and the larger bonding strength, but it has an optimum value. And the bonding strength at the interface can be enable to reach 250-270 MPa, which is nearly the same as that of processed by flame spray. The microhardness along the coating layer depth shows a gradient distribution manner.

  16. 21 CFR 73.1647 - Copper powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Copper powder. 73.1647 Section 73.1647 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing metallic powder prepared from virgin electrolytic copper. It...

  17. Waterborne UV coating for industrial applications

    International Nuclear Information System (INIS)

    Bhattacharya, I.N.

    2007-01-01

    (Full Text): Solvent borne industrial coatings are being replaced by environment friendly coatings like Ultra Violet (UV) or Electron Beam (Eb) cured coatings, Powder coatings and Waterborne coatings. Waterborne systems enjoy the biggest share from this shift. UV and EB coatings provide the advantages of instant cure at room temperature, high scratch and abrasion resistance combined with excellent chemical resistance. Polyurethane (PU) chemistry is the dominant chemistry in Industrial coatings as they provide a very high level of performance. Most PU coatings are solvent based 2-component systems comprising of a resin and a cross linker. Polyurethane dispersions (PUD) in water in single pack are available but mainly addresses the Do It Yourself (DIY) market because of their slow drying speeds. Performance of PUD in most cases is inferior to solvent borne 2-component PU systems.Therefore the combination of PU dispersion and UV/EB curable technology has led to new innovative waterborne polymers called UV curable polyurethane dispersions (UVPUD). UVPUD are zero VOC systems as they are coalescent free. They are higher in molecular weight than standard UV curable products resulting in lower shrinkage coatings and provide good adhesion to substrates. Their low-viscosity makes them suitable for application by spray, curtain coater and even roller coater, without having to use monomers. UVPUD display superior chemical and mechanical properties necessary to protect high quality surface from the challenging usage conditions. UVPUD resins are therefore tailor-made to address performance needs like excellence in outdoor durability, scratch resistance, stain resistance, adhesion etc. UVPUD technology is now growing rapidly in industrial coatings for applications such as resilient flooring, wooden parquet flooring, automotive interior plastics, mobile phones etc. (Author)

  18. Thermal failure of nanostructured thermal barrier coatings with cold sprayed nanostructured NiCrAlY bond coat

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q.; Li, Y.; Zhang, S.L.; Wang, X.R.; Yang, G.J.; Li, C.X.; Li, C.J. [Xi' an Jiaotong Univ., Xi' an (China)

    2008-07-01

    Nanostructured YSZ is expected to exhibit a high strain tolerability due to its low Young's modulus and consequently high durability. In this study, a porous YSZ as the thermal barrier coating was deposited by plasma spraying using an agglomerated nanostructured YSZ powder on a Ni-based superalloy Inconel 738 substrate with a cold-sprayed nanostructured NiCrAlY as the bond coat. The heat treatment in Ar atmosphere was applied to the cold-sprayed bond coat before deposition of YSZ. The isothermal oxidation and thermal cycling tests were applied to examine failure modes of plasma-sprayed nanostructured YSZ. The results showed that YSZ coating was deposited by partially melted YSZ particles. The nonmelted fraction of spray particles retains the porous nanostructure of the starting powder into the deposit. YSZ coating exhibits a bimodal microstructure consisting of nanosized particles retained from the powder and micro-columnar grains formed through the solidification of the melted fraction in spray particles. The oxidation of the bond coat occurs during the heat treatment in Ar atmosphere. The uniform oxide at the interface between the bond coat and YSZ can be formed during isothermal test. The cracks were observed at the interface between TGO/BC or TGO/YSZ after thermal cyclic test. However, the failure of TBCs mainly occurred through spalling of YSZ within YSZ coating. The failure characteristics of plasma-sprayed nanostructured YSZ are discussed based on the coating microstructure and formation of TGO on the bond coat surface. (orig.)

  19. In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

    Science.gov (United States)

    Ning, C Q; Zhou, Y

    2002-07-01

    Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.

  20. Electroless silver coating of rod-like glass particles.

    Science.gov (United States)

    Moon, Jee Hyun; Kim, Kyung Hwan; Choi, Hyung Wook; Lee, Sang Wha; Park, Sang Joon

    2008-09-01

    An electroless silver coating of rod-like glass particles was performed and silver glass composite powders were prepared to impart electrical conductivity to these non-conducting glass particles. The low density Ag-coated glass particles may be utilized for manufacturing conducting inorganic materials for electromagnetic interference (EMI) shielding applications and the techniques for controlling the uniform thickness of silver coating can be employed in preparation of biosensor materials. For the surface pretreatment, Sn sensitization was performed and the coating powders were characterized by scanning electron microscopy (SEM), focused ion beam microscopy (FIB), and atomic force microscopy (AFM) along with the surface resistant measurements. In particular, the use of FIB technique for determining directly the Ag-coating thickness was very effective on obtaining the optimum conditions for coating. The surface sensitization and initial silver loading for electroless silver coating could be found and the uniform and smooth silver-coated layer with thickness of 46 nm was prepared at 2 mol/l of Sn and 20% silver loading.

  1. 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.

  2. Review of Research Work on Ti-BASED Composite Coatings

    Science.gov (United States)

    Gabbitas, Brian; Salman, Asma; Zhang, Deliang; Cao, Peng

    The service life of industrial components is limited predominantly by Chemical corrosion/mechanical wear. The project is concerned with the investigation of the capability of Ti(Al,O)/Al2O3 coatings to improve the service life of tool steel (H13) used for dies in aluminium high pressure die casting. This paper gives a general review on the research work conducted at the University of Waikato on producing and evaluating the titanium/alumina based composite coatings. The powder feedstocks for making the composite coatings were produced by high energy mechanical milling of a mixture of Al and TiO2 powders in two different molar ratios followed by a thermal reaction process. The feedstocks were then thermally sprayed using a high velocity air-fuel (HVAF) technique on H13 steel substrates to produce a Ti(Al,O)/Al2O3 composite coatings. The performance of the coating was assessed in terms of thermal shock resistance and reaction kinetics with molten aluminium. The composite powders and coatings were characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD).

  3. Microstructural evolution of aluminide coatings on Eurofer during heat treatments

    International Nuclear Information System (INIS)

    Bhanumurthy, K.; Krauss, W.; Konys, J.

    2011-01-01

    Development of ceramic coatings are essential for the realization of Demo fusion reactor beyond ITER. These functional coatings have to be stable at high temperatures, provide insulating coatings to reduce MHD effects and also act as corrosion barriers to reduce tritium permeation. Some of important development of high temperature coatings are CVD process, powder slurry coatings, hot-dip aluminization and plasma detonation jet processes. Recently Galvono-Al (ECA) process is being used for depositing Al from organic electrolyte, where Al is existing as an toluol-based Al(C x H y ) complex. The deposit is performed under Ar cover gas at 100 deg C with a deposit rate of 10-12 μm/hr. This process is suitable for coating large and complex shaped assemblies and is a well established industrial process for coating Al for wide range of applications including automobile industry. In order to study the effect of high temperature on these coatings, few Al coated on Eurofer specimens were obtained from M/s. Rasant-Alcotec, Germany. The thickness of these coating is around 20 μm. The objective of the presents studies is to subject these coatings to standard heat treatment schedule of Eurofer and study the evolution of microchemistry and microstructure

  4. Porosity and wear resistance of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermal-sprayed coatings offer practical and economical solutions for corrosion and wear protection of components or tools. To improve the coating properties, heat treatment such as preheat is applied. The selection of coating and substrate materials is a key factor in improving the quality of the coating morphology after the heat treatment. This paper presents the experimental results regarding the effect of preheat temperatures, i.e. 200°C, 300°C and 400°C, on porosity and wear resistance of tungsten carbide (WC) coating sprayed by flame thermal coating. The powders and coatings morphology were analyzed by a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectrometry (FE-SEM/EDS), whereas the phase identification was performed by X-Ray diffraction technique (XRD). In order to evaluate the quality of the flame spray obtained coatings, the porosity, micro-hardness and wear rate of the specimens was determined. The results showed that WC coating gives a higher surface hardness from 1391 HVN up to 1541 HVN compared to that of the non-coating. Moreover, the wear rate increased from 0.072 mm3/min. to 0.082 mm3/min. when preheat temperature was increased. Preheat on H13 steel substrate can reduce the percentage of porosity level from 10.24 % to 3.94% on the thermal spray coatings.

  5. Study on synthesis of ultrafine Cu–Ag core–shell powders with high electrical conductivity

    International Nuclear Information System (INIS)

    Peng Yuhsien; Yang Chihhao; Chen Kuanting; Popuri, Srinivasa R.; Lee, Ching-Hwa; Tang, Bo-Shin

    2012-01-01

    Highlights: ► This synthesis method is relatively facile, novel and eco-friendly. ► Toxic agents were not used for chelating agent, reductant or dispersant in our method. ► The reaction can under room temperature for energy saving purpose. ► Cu–Ag core–shell powders with homogeneous cover-silver layer. ► The resistivity of Cu–Ag core–shell powders has the same value as the pure silver. - Abstract: Cu–Ag composite powders with high electrical conductivity were synthesized by electroless plating of silver sulfate, copper powders with eco-friendly sodium citrate as reducing agent, dispersant and chelating agent in an aqueous system. The influences of sodium citrate/Ag ratio on Ag coatings of Cu powders were investigated. Ag was formed a dense coating on the surface of Cu powders at a molar ratio of sodium citrate/Ag = 0.07/1. SEM showed an uniformity of Ag coatings on Cu powders. SEM-EDX also revealed that Cu cores were covered by Ag shells on the whole. The surface composition analysis by XPS indicated that without Cu or Ag atoms in the surface were oxidized. The resistivity measurements of Cu–Ag paste shows that they have closer resistivity as the pure silver paste's after 250 °C for 30 min heat-treatment (2.55 × 10 −4 Ω cm) and 350 °C for 30 min heat-treatment (1.425 × 10 −4 Ω cm).

  6. Low Temperature Metal Coating Method Final Report CRADA No. TSB-1155-95

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sang-Wook [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gabel, Howard [Innovative Technology, Inc., Santa Barbara, CA (United States)

    2018-01-19

    A new metal coating method, cidled KEM (kinetic energy metal.lization), demonstrated in the laboratory by lnovati, utilized fast-moving solid particIes entrained in a gas that are caused to fiow through a nozzIe to effect particle deposition on metal surfaces at room temperature conditions. This method (US Patent 5,795,626) was an attractive and viabIe alternative to the currentIy available high-temperature coating methods avaiIabIe. Since it differs significantly from existing metal coating technologies, a brief description of the method is incIuded here. The proposed method, KEM, achieves cohesive and adhesive metallurgical bonding through the high-speed coUision of powder with a substrate and the subsequent discharge of electrical charge at the substrate. Such coating is effected by entraining metal powder in a gas and accelerating this mixture through a supersonic nozzle. The gas/powder is directed towards the substrate to be coated. Collisions occur, initiaIly between the powder and the substrate, and, as the first Iayer of the coating forms, between the powder and the coating. During these collisions the powder is rapidly deformed, causing the exposure of fresh (oxide free) active metal surface. When these’active surfaces contact one another, they agglomerate and form true metaIIurgicaI bonds. The resultant coating has Iow porosity and high adhesive and cohesive strength. The formation of metaIIurgicaI bonds is potentiated by the discharge of electrical energy. This electrical energy is the result of triboeIectric charging of the particIes during acceleration and transit to the nozzIe. An advantage of the method is that it does not raise the temperature of the powder being appLiedor that of the substrate. Consequently, materials sensitive to high temperature may be applied without changing Me properties of the materkd or substrate.

  7. Plasma sprayed rutile titania-nanosilver antibacterial coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Jinjin [Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhao, Chengjian [National Key Laboratory of Human Factors Engineering, Department of ECLSS, China Astronaut Researching and Training Center, Beijing, 100094 (China); Zhou, Jingfang [Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA, 5095 (Australia); Li, Chunxia [National Key Laboratory of Human Factors Engineering, Department of ECLSS, China Astronaut Researching and Training Center, Beijing, 100094 (China); Shao, Yiran; Shi, Chao [Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhu, Yingchun, E-mail: yzhu@mail.sic.ac.cn [Key Lab of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2015-11-15

    Graphical abstract: - Highlights: • TiO{sub 2}/Ag feedstock powders containing 1–10,000 ppm silver nanoparticles were double sintered and deposited by plasma spray. • TiO{sub 2}/Ag coatings were composed of pure rutile phase and homogeneously-distributed metallic silver. • TiO{sub 2}/Ag coatings with more than 10 ppm silver nanoparticles exhibited strong antibacterial activity against E. coli and S. aureus. - Abstract: Rutile titania (TiO{sub 2}) coatings have superior mechanical properties and excellent stability that make them preferential candidates for various applications. In order to prevent infection arising from bacteria, significant efforts have been focused on antibacterial TiO{sub 2} coatings. In the study, titania-nanosilver (TiO{sub 2}/Ag) coatings with five different kinds of weight percentages of silver nanoparticles (AgNPs) were prepared by plasma spray. The feedstock powders, which had a composition of rutile TiO{sub 2} powders containing 1–10,000 ppm AgNPs, were double sintered and deposited on stainless steel substrates with optimized spraying parameters. X-Ray diffraction and scanning electron microscopy were used to analysize the phase composition and surface morphology of TiO{sub 2}/Ag powders and coatings. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were employed to examine the antibacterial activity of the as-prepared coatings by bacterial counting method. The results showed that silver existed homogeneously in the TiO{sub 2}/Ag coatings and no crystalline changed happened in the TiO{sub 2} structure. The reduction ratios on the TiO{sub 2}/Ag coatings with 10 ppm AgNPs were as high as 94.8% and 95.6% for E. coli and S. aureus, respectively, and the TiO{sub 2}/Ag coatings with 100–1000 ppm AgNPs exhibited 100% bactericidal activity against E. coli and S. aureus, which indicated the TiO{sub 2}/Ag coatings with more than 10 ppm AgNPs had strong antibacterial activity. Moreover, the main factors influencing the

  8. Plasma sprayed rutile titania-nanosilver antibacterial coatings

    International Nuclear Information System (INIS)

    Gao, Jinjin; Zhao, Chengjian; Zhou, Jingfang; Li, Chunxia; Shao, Yiran; Shi, Chao; Zhu, Yingchun

    2015-01-01

    Graphical abstract: - Highlights: • TiO_2/Ag feedstock powders containing 1–10,000 ppm silver nanoparticles were double sintered and deposited by plasma spray. • TiO_2/Ag coatings were composed of pure rutile phase and homogeneously-distributed metallic silver. • TiO_2/Ag coatings with more than 10 ppm silver nanoparticles exhibited strong antibacterial activity against E. coli and S. aureus. - Abstract: Rutile titania (TiO_2) coatings have superior mechanical properties and excellent stability that make them preferential candidates for various applications. In order to prevent infection arising from bacteria, significant efforts have been focused on antibacterial TiO_2 coatings. In the study, titania-nanosilver (TiO_2/Ag) coatings with five different kinds of weight percentages of silver nanoparticles (AgNPs) were prepared by plasma spray. The feedstock powders, which had a composition of rutile TiO_2 powders containing 1–10,000 ppm AgNPs, were double sintered and deposited on stainless steel substrates with optimized spraying parameters. X-Ray diffraction and scanning electron microscopy were used to analysize the phase composition and surface morphology of TiO_2/Ag powders and coatings. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were employed to examine the antibacterial activity of the as-prepared coatings by bacterial counting method. The results showed that silver existed homogeneously in the TiO_2/Ag coatings and no crystalline changed happened in the TiO_2 structure. The reduction ratios on the TiO_2/Ag coatings with 10 ppm AgNPs were as high as 94.8% and 95.6% for E. coli and S. aureus, respectively, and the TiO_2/Ag coatings with 100–1000 ppm AgNPs exhibited 100% bactericidal activity against E. coli and S. aureus, which indicated the TiO_2/Ag coatings with more than 10 ppm AgNPs had strong antibacterial activity. Moreover, the main factors influencing the antibacterial properties of TiO_2/Ag coatings were discussed with

  9. 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

  10. Turbostratic boron nitride coated on high-surface area metal oxide templates

    DEFF Research Database (Denmark)

    Klitgaard, Søren Kegnæs; Egeblad, Kresten; Brorson, M.

    2007-01-01

    Boron nitride coatings on high-surface area MgAl2O4 and Al2O3 have been synthesized and characterized by transmission electron microscopy and by X-ray powder diffraction. The metal oxide templates were coated with boron nitride using a simple nitridation in a flow of ammonia starting from ammonium...

  11. Laser cladding of Al-Si/SiC composite coatings : Microstructure and abrasive wear behavior

    NARCIS (Netherlands)

    Anandkumar, R.; Almeida, A.; Vilar, R.; Ocelik, V.; De Hosson, J.Th.M.

    2007-01-01

    Surface coatings of an Al-Si-SiC composite were produced on UNS A03560 cast Al-alloy substrates by laser cladding using a mixture of powders of Al-12 wt.% Si alloy and SiC. The microstructure of the coatings depends considerably on the processing parameters. For a specific energy of 26 MJ/m2 the

  12. Shock diffraction in alumina powder

    International Nuclear Information System (INIS)

    Venz, G.; Killen, P.D.; Page, N.W.

    1996-01-01

    In order to produce complex shaped components by dynamic compaction of ceramic powders detailed knowledge of their response under shock loading conditions is required. This work attempts to provide data on release effects and shock attenuation in 1 μm and 5 μm α-alumina powders which were compacted to between 85 % and 95 % of the solid phase density by the impact of high velocity steel projectiles. As in previous work, the powder was loaded into large cylindrical dies with horizontal marker layers of a contrasting coloured powder to provide a record of powder displacement in the recovered specimens. After recovery and infiltration with a thermosetting resin the specimens were sectioned and polished to reveal the structure formed by the passage of the projectile and shock wave. Results indicate that the shock pressures generated were of the order of 0.5 to 1.4 GPa and higher, with shock velocities and sound speeds in the ranges 650 to 800 m/s and 350 to 400 m/s respectively

  13. A Study on the Manufacturing Properties of Crack Self-Healing Capsules Using Cement Powder for Addition to Cement Composites

    OpenAIRE

    Choi, Yun-Wang; Oh, Sung-Rok; Choi, Byung-Keol

    2017-01-01

    We fabricated crack self-healing capsules using cement powder for mixing into cement composites and evaluated the properties of the capsule manufacturing process in this study. The manufacture of the self-healing capsules is divided into core production processing of granulating cement in powder form and a coating process for creating a wall on the surfaces of the granulated cement particles. The produced capsules contain unhardened cement and can be mixed directly with the cement composite m...

  14. Novel Nanocrystalline Intermetallic Coatings for Metal Alloys in Coal-fired Environments

    Energy Technology Data Exchange (ETDEWEB)

    Z. Zak Fang; H. Y. Sohn

    2009-08-31

    Intermetallic coatings (iron aluminide and nickel aluminide) were prepared by a novel reaction process. In the process, the aluminide coating is formed by an in-situ reaction between the aluminum powder fed through a plasma transferred arc (PTA) torch and the metal substrate (steel or Ni-base alloy). Subjected to the high temperature within an argon plasma zone, aluminum powder and the surface of the substrate melt and react to form the aluminide coatings. The prepared coatings were found to be aluminide phases that are porosity-free and metallurgically bonded to the substrate. The coatings also exhibit excellent high-temperature corrosion resistance under the conditions which simulate the steam-side and fire-side environments in coal-fired boilers. It is expected that the principle demonstrated in this process can be applied to the preparation of other intermetallic and alloy coatings.

  15. 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

  16. Mikrostruktur dan Karakterisasi Sifat Mekanik Lapisan Cr3C2-NiAl-Al2O3 Hasil Deposisi Dengan Menggunakan High Velocity Oxygen Fuel Thermal Spray Coating

    Directory of Open Access Journals (Sweden)

    Edy Riyanto

    2012-03-01

    Full Text Available Surface coating processing of industrial component with thermal spray coatings have been applied in many industrial fields. Ceramic matrix composite coating which consists of Cr3C2-Al2O3-NiAl had been carried out to obtain layers of material that has superior mechanical properties to enhance component performance. Deposition of CMC with High Velocity Oxygen Fuel (HVOF thermal spray coating has been employed. This study aims to determine the effect of powder particle size on the microstructure, surface roughness and hardness of the layer, by varying the NiAl powder particle size. Test results show NiAl powder particle size has an influence on the mechanical properties of CMC coating. Hardness of coating increases and surface roughness values of coating decrease with smaller NiAl particle size.  

  17. Stochastic Computer Simulation of Cermet Coatings Formation

    Directory of Open Access Journals (Sweden)

    Oleg P. Solonenko

    2015-01-01

    Full Text Available An approach to the modeling of the process of the formation of thermal coatings lamellar structure, including plasma coatings, at the spraying of cermet powders is proposed. The approach based on the theoretical fundamentals developed which could be used for rapid and sufficiently accurate prediction of thickness and diameter of cermet splats as well as temperature at interface “flattening quasi-liquid cermet particle-substrate” depending on the key physical parameters (KPPs: temperature, velocity and size of particle, substrate temperature, and concentration of finely dispersed solid inclusions uniformly distributed in liquid metal binder. The results are presented, which concern the development of the computational algorithm and the program complex for modeling the process of laying the splats in the coating with regard to the topology of its surface, which varies dynamically at the spraying, as well as the formation of lamellar structure and porosity of the coating. The results of numerical experiments are presented through the example of thermal spraying the cermet TiC-30 vol.% NiCr powder, illustrating the performance of the developed computational technology.

  18. Preparation of Porous Hydroxyapatite Tablets and Porous Hydroxyapatite Coatings for Orthopaedic Use

    International Nuclear Information System (INIS)

    Mendez-Gonzalez, M.

    2004-01-01

    Porous hydroxyapatite tablets and coatings on metal substrates were obtained by the addition of polymeric additives and liofilization. Both tablets and coatings were characterized by scanning electron microscopy and x-ray diffraction. Coatings obtained by plasma spraying also exhibited interconnected porous of 100 μm while coatings obtained by laser ablation did not show any porosity. The diffraction patterns of the deposited HA were similar to that of the powder obtained by the precipitation method suggesting that no significant changes occurred during the coating procedure

  19. Particle Engineering Via Mechanical Dry Coating in the Design of Pharmaceutical Solid Dosage Forms.

    Science.gov (United States)

    Qu, Li; Morton, David A V; Zhou, Qi Tony

    2015-01-01

    Cohesive powders are problematic in the manufacturing of pharmaceutical solid dosage forms because they exhibit poor flowability, fluidization and aerosolization. These undesirable bulk properties of cohesive powders represent a fundamental challenge in the design of efficient pharmaceutical manufacturing processes. Recently, mechanical dry coating has attracted increasing attention as it can improve the bulk properties of cohesive powders in a cheaper, simpler, safer and more environment-friendly way than the existing solvent-based counterparts. In this review, mechanical dry coating techniques are outlined and their potential applications in formulation and manufacturing of pharmaceutical solid dosage forms are discussed. Reported data from the literature have shown that mechanical dry coating holds promise for the design of superior pharmaceutical solid formulations or manufacturing processes by engineering the interfaces of cohesive powders in an efficient and economical way.

  20. Method of solidifying powderous wastes

    International Nuclear Information System (INIS)

    Kakimoto, Akira; Miyake, Takashi; Sato, Shuichi; Inagaki, Yuzo.

    1985-01-01

    Purpose: To improve the properties of solidification products, in the case of solidifying powderous wastes with thermosetting resins. Method. A solvent for the solution of the thermosetting resin is admixed with the powderous wastes into a paste-like form prior to adding the resin to the wastes, which are then mixed with the resin solution. As the result, those solidification products having the specific gravity and the compression strength more excellent than those of the conventional ones, and much higher than the reference values can be obtained. (Kamimura, M.)

  1. Demonstration Of A Nanomaterial-Modified Primer For Use In Corrosion-Inhibiting Coating Systems

    Science.gov (United States)

    2011-11-01

    resin packages/binders, can cause a high-build coating thickness that can be prone to chipping and “mud cracking ” if not properly applied. The...for all non-magnetic coatings on a ferrous (magnetic) substrate, e.g. paint, plastic, enamel , powder, rubber, ceramic, galvanising, zinc, sprayed... cracking during the scribing process due to the brittle coating system on the intermediate primer coupons (16 and 22) as well as coupon 11. Mildew

  2. The Insulation of Copper Wire by the Electrostatic Coating Process.

    Science.gov (United States)

    1983-06-30

    Caster full production lines produce more uniform coating thicknesses. -18- U AM NC. IO C FWIO~k TX3M ..... ....... Z . A A I~ ~ 15X 7-., r - ’ r 15X... modification to meet specific usage requirements. t * -68- 482 5 APPENDIX CLIQUINITE’ COATING PRODU(:TS LIQUINITEE-COATING POWDERS FEP (Fluorinated Ethylene...Loss from Dissipation Factor (60 Hz-2xl0 9Hz) 0.2-1.2001 Revolving Disc, mg (60 Hz -2 x iO0 Hz) *CS 17 Wheel . 100 cycles 2.2 Surface Resistivity (250

  3. Improvement of Silicide Coating Method as Diffusion Barrier for U-Mo Dispersion Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ji Min; Kim, Sunghwan; Lee, Kyu Hong; Park, Jong Man [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The excessive interaction between the U-Mo alloys and their surrounding Al matrix lead to excessive local swelling called 'pillowing'. For this reason, KAERI suggested several remedies such as alloying U-Mo with Ti, or Al matrix with Si. In addition, silicide or nitride coatings on the surface of U-Mo particles have also been proposed to hinder the growth of the interaction layer. In this study, centrifugally atomized U-Mo-Ti alloy powders were coated with silicide layers. The coating process was improved when compared to the previous coating in terms of the ball milling and heat treatment conditions. Subsequently, silicide coated U-Mo-Ti powders and pure aluminum powders were mixed and made into a compact for the annealing test. The compacts were annealed at 550 .deg. C for 2hr, and characterized using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). 1. Uniform, homogeneous, thickness controllable silicide layers were successfully coated on the surface of U-7wt%Mo-1wt%Ti powders. 2. U{sub 3}Si, U{sub 3}Si{sub 2} silicide layers formed on the surface of U-7wt%Mo-1wt%Ti powders, and were identified by XRD and EDS analyses.

  4. A two layer coating system for metallic substrates

    International Nuclear Information System (INIS)

    1979-01-01

    Plasma deposited cermet coatings are used for protecting components in sodium or helium cooled reactors. An inner layer of cermet made from a powder mixture of chromium carbide and a nickel -20% chromium and an outer layer of chromium carbide is preferred. (UK)

  5. Characterization of silane coated hollow sphere alumina-reinforced

    Indian Academy of Sciences (India)

    Silane coated hollow sphere alumina ceramic particles were moulded with ultra high molecular weight polyethylene (UHMWPE) to form a series of composites with alumina weight percent in the range from 15 to 50. The composites were prepared in a cylindrical mould using powder-processing technique. The composites ...

  6. 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...

  7. Robotic weld overlay coatings for erosion control

    Science.gov (United States)

    The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB's.

  8. NON-POLLUTING REPLACEMENT FOR CHROMATE CONVERSION COATING & ZINC PHOSPHATING IN POWDER COATING APPLICATIONS

    Science.gov (United States)

    Picklex, a proprietary formulation, is an alternative to conventional metal surface pretreatments. Its developers claim that it does not produce waste or lower production rates, and it will maintain performance compared to conventional processes. A laboratory program was designed...

  9. The analysis of powder diffraction data

    International Nuclear Information System (INIS)

    David, W.I.F.; Harrison, W.T.A.

    1986-01-01

    The paper reviews neutron powder diffraction data analysis, with emphasis on the structural aspects of powder diffraction and the future possibilities afforded by the latest generation of very high resolution neutron and x-ray powder diffractometers. Traditional x-ray powder diffraction techniques are outlined. Structural studies by powder diffraction are discussed with respect to the Rietveld method, and a case study in the Rietveld refinement method and developments of the Rietveld method are described. Finally studies using high resolution powder diffraction at the Spallation Neutron Source, ISIS at the Rutherford Appleton Laboratory are summarized. (U.K.)

  10. Coating materials

    International Nuclear Information System (INIS)

    Ozeki, Takao; Kimura, Tadashi; Kobayashi, Juichi; Maeda, Yutaka; Nakamoto, Hideo.

    1969-01-01

    A non-solvent type coating material composition having properties as good as thermosetting acrylic or amino alkid resins is provided by employing active energy irradiation, particularly electron beams, using a radically polymerizable low molecular compound (A) (hereafter called an oligomer) containing at least two vinyl radicals in one molecule. This oligomer is produced by reacting an epoxy-containing vinyl monomer with alpha-, beta-ethylene unsaturated carboxylic acids or their anhydrides. The composition (I) contains 10% - 100% of this oligomer. In embodiments, an oligomer having a fiberous trivinyl construction is produced by reacting 180 parts by weight of glycidyl methacrylate ester with 130 parts of itaconic acid in the presence of a polymerization-inhibitor and an addition reaction catalyst at 90 0 C for 6 hours. In practice, the coating material compositions (1), consist of the whole oligomer [I-1]; (2), consist of 10-90% of (A) component and 90%-10% of vinyl monomers containing at least 30% (meth) acrylic monomer [I-2]; (3), 10%-90% of component (A) and 90%-10% of other monomers containing at least two vinyl radicals [I-3]; (4), a mixture of (I-2) and (I-3), [I-4]; and (5), consist of 50% or less unsaturated polyester of 500-5,000 molecular weight range or drying oil, or alkyd resin of 500-5,000 molecular weight range modified by drying oil, [I-5]. As a catalyst a tertiary amino vinyl compound is preferred. Five examples are given. (Iwakiri, K.)

  11. Experience of high-nitrogenous steel powder application in repairs and surface hardening of responsible parts for power equipment by plasma spraying

    Science.gov (United States)

    Kolpakov, A. S.; Kardonina, N. I.

    2016-02-01

    The questions of the application of novel diffusion-alloying high-nitrogenous steel powders for repair and surface hardening of responsible parts of power equipment by plasma spraying are considered. The appropriateness of the method for operative repair of equipment and increasing its service life is justified. General data on the structure, properties, and manufacture of nitrogen-, aluminum-, and chromium-containing steel powders that are economically alloyed using diffusion are described. It is noted that the nitrogen release during the decomposition of iron nitrides, when heating, protects the powder particles from oxidation in the plasma jet. It is shown that the coating retains 50% of nitrogen that is contained in the powder. Plasma spraying modes for diffusion-alloying high-nitrogenous steel powders are given. The service properties of plasma coatings based on these powders are analyzed. It is shown that the high-nitrogenous steel powders to a nitrogen content of 8.9 wt % provide the necessary wear resistance and hardness of the coating and the strength of its adhesion to the substrate and corrosion resistance to typical aggressive media. It is noted that increasing the coating porosity promotes stress relaxation and increases its thickness being limited with respect to delamination conditions in comparison with dense coatings on retention of the low defectiveness of the interface and high adhesion to the substrate. The examples of the application of high-nitrogenous steel powders in power engineering during equipment repairs by service companies and overhaul subdivisions of heat power plants are given. It is noted that the plasma spraying of diffusion-alloyed high-nitrogenous steel powders is a unique opportunity to restore nitrided steel products.

  12. Effects of variations in coating materials and process conditions on the thermal cycle properties of NiCrAlY/YSZ thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tang Feng [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)]. E-mail: ftang@ucdavis.edu; Ajdelsztajn, Leonardo [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Kim, George E. [Perpetual Technologies, Montreal, Que., H3E 1T8 (Canada); Provenzano, Virgil [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Schoenung, Julie M. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

    2006-06-15

    Thermal cycle tests were conducted on a variety of thermal barrier coating (TBC) specimens with bond coats that had been prepared in different ways. Variables include: (1) different thermal spray processes (high velocity oxy-fuel (HVOF) spray and low pressure plasma spray (LPPS)) (2) different feedstock powder (gas-atomized and cryomilled) (3) the introduction of nano-sized alumina additives (particles and whiskers) and (4) with and without a post-spray vacuum heat treatment. The results show that the cryomilling of the NiCrAlY powder and the post-spray heat treatment in vacuum can both lead to significant improvement in the thermal cycle lifetime of the TBCs. The TBC specimens with LPPS bond coats also generally showed longer lifetimes than those with HVOF bond coats. In contrast, the intentional dispersion of alumina particles or whiskers in the NiCrAlY powders during cryomilling did not result in the further improvement of the lifetime of the TBCs. Microstructural evolution, including the thermally grown oxide (TGO) formation, the distribution of the dispersoids in the bond coat, the internal oxidation of the bond coat, the bond coat shrinkage during the thermal cycle tests and the reduction of the ZrO{sub 2} in the top coat during the heat treatment in vacuum, was investigated.

  13. Electro/powder separation process

    International Nuclear Information System (INIS)

    Dunn, J.P.

    1977-01-01

    A report is presented to introduce the ELECTRO/POWDER process to the P/M Industry. The process effectively uses electrostatic forces to convey, sort, meter, and blend fine powders. The major advantages of this separating process consist of the processing of primary particles, low particle energy due to particle velocity control and the pattern of particle movement over the sieve (vertical oscillation of particles above the sieve aperture). The report briefly describes the forces involved in both mechanical and sieving devices, with major emphasis on the operating principles of this process. Sieve separation of particulates is basically the result of two physical separating processes which occur simultaneously or independently; separation (dispersion) of particulates from each other and the size separation by passage through fixed apertures. In order to accomplish this goal, mechanical sieving devices utilize various motions to induce shear forces between the sieve surface and the particulates, and between the particulates themselves. It is noted that the ELECTRO/POWDER process is making steady progress in becoming an industrial tool for sieving and feeding of fine particles. Its potential extends into both the blending and admixing of powders, either by incorporating two opposing feeders, one being charged with the opposite polarity or by modifying the ELECTRO/SIEVE to incorporate more than one input and a solid electrode to replace the sieve electrode

  14. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  15. Oxidized Metal Powders for Mechanical Shock and Crush Safety Enhancers; TOPICAL

    International Nuclear Information System (INIS)

    GARINO, TERRY J.

    2002-01-01

    The use of oxidized metal powders in mechanical shock or crush safety enhancers in nuclear weapons has been investigated. The functioning of these devices is based on the remarkable electrical behavior of compacts of certain oxidized metal powders when subjected to compressive stress. For example, the low voltage resistivity of a compact of oxidized tantalum powder was found to decrease by over six orders of magnitude during compaction between 1 MPa, where the thin, insulating oxide coatings on the particles are intact, to 10 MPa, where the oxide coatings have broken down along a chain of particles spanning the electrodes. In this work, the behavior of tantalum and aluminum powders was investigated. The low voltage resistivity during compaction of powders oxidized under various conditions was measured and compared. In addition, the resistivity at higher voltages and the dielectric breakdown strength during compaction were also measured. A key finding was that significant changes in the electrical properties persist after the removal of the stress so that a mechanical shock enhancer is feasible. This was verified by preliminary shock experiments. Finally, conceptual designs for both types of enhancers are presented

  16. Neodymium conversion layers formed on zinc powder for improving electrochemical properties of zinc electrodes

    International Nuclear Information System (INIS)

    Zhu Liqun; Zhang Hui; Li Weiping; Liu Huicong

    2008-01-01

    Zinc powder, as active material of secondary alkaline zinc electrode, can greatly limit the performance of zinc electrode due to corrosion and dendritic growth of zinc resulting in great capacity-loss and short cycle life of the electrode. This work is devoted to modification study of zinc powder with neodymium conversion films coated directly onto it using ultrasonic immersion method for properties improvement of zinc electrodes. Scanning electron microscopy and other characterization techniques are applied to prove that neodymium conversion layers are distributing on the surface of modified zinc powder. The electrochemical performance of zinc electrodes made of such modified zinc powder is investigated through potentiodynamic polarization, potentiostatic polarization and cyclic voltammetry. The neodymium conversion films are found to have a significant effect on inhibition corrosion capability of zinc electrode in a beneficial way. It is also confirmed that the neodymium conversion coatings can obviously suppress dendritic growth of zinc electrode, which is attributed to the amelioration of deposition state of zinc. Moreover, the results of cyclic voltammetry reveal that surface modification of zinc powder enhances the cycle performance of the electrode mainly because the neodymium conversion films decrease the amounts of ZnO or Zn(OH) 2 dissolved in the electrolyte

  17. Polymer quenched prealloyed metal powder

    Science.gov (United States)

    Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  18. Advanced oxide powders processing based on cascade plasma

    International Nuclear Information System (INIS)

    Solonenko, O P; Smirnov, A V

    2014-01-01

    Analysis of the potential advantages offered to thermal spraying and powder processing by the implementation of plasma torches with inter-electrode insert (IEI) or, in other words, cascade plasma torches (CPTs) is presented. The paper provides evidence that the modular designed single cathode CPT helps eliminate the following major disadvantages of conventional plasma torches: plasma parameters drifting, 1-5 kHz pulsing of plasma flow, as well as excessive erosion of electrodes. More stable plasma results in higher quality, homogeneity and reproducibility of plasma sprayed coatings and powders treated. In addition, CPT offers an extremely wide operating window, which allows better control of plasma parameters, particle dwell time and, consequently, particle temperature and velocity within a wide range by generating high enthalpy quasi-laminar plasmas, medium enthalpy transient plasmas, as well as relatively low enthalpy turbulent plasmas. Stable operation, flexibility with plasma gases as well as wide operating window of CPT should help significantly improve the existing plasma spraying processes and coatings, and also help develop new advanced technologies

  19. Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

    Science.gov (United States)

    Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

    2009-01-01

    Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

  20. Mechanical and tribological property of single layer graphene oxide reinforced titanium matrix composite coating

    Science.gov (United States)

    Hu, Zengrong; Li, Yue; Fan, Xueliang; Chen, Feng; Xu, Jiale

    2018-04-01

    Single layer grapheme oxide Nano sheets and Nano titanium powder were dispersed in deionized water by ultrasonic dispersion. Then the mixed solution was pre-coating on AISI4140 substrate. Using laser sintering process to fabricated grapheme oxide and Ti composite coating. Microstructures and composition of the composite coating was studied by Scanning Electron Microscopy (SEM), x-ray diffract meter (XRD) and Raman spectroscopy. Raman spectrum, XRD pattern and SEM results proved that grapheme oxide sheets were dispersed in the composite coating. The composite coating had much higher average Vickers hardness values than that of pure Ti coating. The tribological performance of the composite coatings became better while the suitable GO content was selected. For the 2.5wt. % GO content coating, the friction coefficient was reduced to near 0.1.

  1. Effects of Laser Re-melting on the Corrosion Properties of HVOF Coatings

    Science.gov (United States)

    Yilbas, B. S.; Toor, I. H.; Patel, F.; Baig, M. A.

    2013-05-01

    HVOF coating of Inconel 625 powder on carbon steel is carried out. Laser melting of the resulting coating is realized to improve coating structural integrity. Morphological and microstructural changes are examined in the coating prior and after laser treatment process using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction (XRD). The residual stress developed is measured on the surface vicinity of the laser-treated coating using the XRD technique. The corrosion resistance of the laser-treated and untreated coating surfaces is measured, incorporating the potentiodynamic tests in 0.5 M NaCl aqueous solution. It is found that laser treatment reduces the pores and produces cellular structures with different sizes and orientations in the coating. Laser-controlled melting improves the corrosion resistance of the coating surface.

  2. Effect of the addition of Sm2O3 on the microstructure of laser cladding alloy coating layers

    Science.gov (United States)

    Zhang, Shi Hong; Li, Ming Xi; Cho, Tong Yul; Yoon, Jae Hong; Fang, Wei; Joo, Yun Kon; Kang, Jin Ho; Lee, Chan Gyu

    2008-06-01

    The effects on the microstructures and phases of coating layers by the addition of micron-sized (m) and nano-sized (n) (m&n) Sm2O3 powders were investigated. The coating materials, which were prepared by means of 2.0 kW CO2 laser cladding, consist of a powder mixture of m Ni-based alloy (NBA) powders comprising 1.5 wt.% m Sm2O3 and 3.0% n Sm2O3 powders. The results indicate that γ-Ni, Cr23C6 and Ni3B are the primary phases of the NBA coatings. The Fe7Sm and Ni3Si phases are highlighted by the addition of m&n Sm2O3 powders. From the substrate, planar crystal layers are first grown in all NBA and m&n Sm2O3/NBA coatings. The dendrite growth then occurs as a result of the addition of the m Sm2O3 powder, and the equiaxed dendrite growth occurs as a result of the addition of the n Sm2O3. With the addition of a rare earth oxide such as Sm2O3 powder, the width of the planar crystal becomes smaller than that of the NBA coating.

  3. Tribological wear behavior of diamond reinforced composite coating

    International Nuclear Information System (INIS)

    Venkateswarlu, K.; Ray, Ajoy Kumar; Gunjan, Manoj Kumar; Mondal, D.P.; Pathak, L.C.

    2006-01-01

    In the present study, diamond reinforced composite (DRC) coating has been applied on mild steel substrate using thermal spray coating technique. The composite powder consists of diamond, tungsten carbide, and bronze, which was mixed in a ball mill prior deposition by thermal spray. The microstructure and the distribution of diamond and tungsten carbide particle in the bronze matrix were studied. The DRC-coated mild steel substrates were assessed in terms of their high stress abrasive wear and compared with that of uncoated mild steel substrates. It was observed that when sliding against steel, the DRC-coated sample initially gains weight, but then loses the transferred counter surface material. In case of abrasive wear, the wear rate was greatly reduced due to the coating; wherein the wear rate decreased with increase in diamond content

  4. Nanostructured Si-substituted hydroxyapatite coatings for biomedical applications

    International Nuclear Information System (INIS)

    Rau, Julietta V.; Fosca, Marco; Cacciotti, Ilaria; Laureti, Sara; Bianco, Alessandra; Teghil, Roberto

    2013-01-01

    In the present work, the Si-HAp coatings were deposited on titanium substrates by Pulsed Laser Deposition technique. For deposition, the Si-HAp targets (1.4 wt.% of Si), produced starting from wet synthesized powders, were used. The properties of coatings were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and Vickers microhardness. The obtained Si-HAp coatings presented a nanosized structure, proper thickness and hardness for applications in orthopedical and dental surgery, aimed at improving the stability and the osteointegration of bone implants. - Highlights: ► Pulsed Laser Deposition method was applied to coat heated Titanium supports. ► Films were deposited using a target of Silicon-Hydroxyapatite sintered ceramics. ► Nanostructured crystalline hard film was grown replicating target composition. ► Prepared coating could be used for orthopedic and dental implants applications

  5. Nanostructured Si-substituted hydroxyapatite coatings for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Rau, Julietta V., E-mail: giulietta.rau@ism.cnr.it [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Fosca, Marco [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Cacciotti, Ilaria [Università di Roma “Tor Vergata”, Dipartimento di Ingegneria Industriale,UR INSTM “Roma Tor Vergata”, Via del Politecnico, 1-00133 Rome (Italy); Laureti, Sara [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via Salaria km 29.300-00016 Monterotondo Scalo (RM) (Italy); Bianco, Alessandra [Università di Roma “Tor Vergata”, Dipartimento di Ingegneria Industriale,UR INSTM “Roma Tor Vergata”, Via del Politecnico, 1-00133 Rome (Italy); Teghil, Roberto [Università della Basilicata, Dipartimento di Scienze, Via dell' Ateneo Lucano 10-85100, Potenza (Italy)

    2013-09-30

    In the present work, the Si-HAp coatings were deposited on titanium substrates by Pulsed Laser Deposition technique. For deposition, the Si-HAp targets (1.4 wt.% of Si), produced starting from wet synthesized powders, were used. The properties of coatings were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and Vickers microhardness. The obtained Si-HAp coatings presented a nanosized structure, proper thickness and hardness for applications in orthopedical and dental surgery, aimed at improving the stability and the osteointegration of bone implants. - Highlights: ► Pulsed Laser Deposition method was applied to coat heated Titanium supports. ► Films were deposited using a target of Silicon-Hydroxyapatite sintered ceramics. ► Nanostructured crystalline hard film was grown replicating target composition. ► Prepared coating could be used for orthopedic and dental implants applications.

  6. Surface oxidation phenomena of boride coatings grown on iron

    International Nuclear Information System (INIS)

    Carbucicchio, M.; Palombarini, G.; Sambogna, G.

    1992-01-01

    Very hard boride coatings are grown on various metals using thermochemical as well as chemical vapour deposition techniques. In this way many surface properties, and in particular the wear resistance, can be considerably improved. Usually, also the corrosion behaviour of the treated components is important. In particular, oxidizing atmospheres are involved in many applications where, therefore, coating-environment interactions can play a relevant role. In a previous work, the early stages of the oxidation of iron borides were studied by treating single phase compacted powders in flowing oxygen at low temperatures (300-450deg C). In the present paper, the attention is addressed to the oxidation of both single phase and polyphase boride coatings thermochemically grown on iron. The single phase boride coatings were constituted by Fe 2 B, while the polyphase coatings were constituted by an inner Fe 2 B layer and an outer FeB-base layer. All the boride layers displayed strong (002) preferred crystallographic orientations. (orig.)

  7. Graphene Coatings

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Bøggild, Peter

    2014-01-01

    Owing to its remarkable electrical and mechanical properties, graphene has been attracting tremendous interest in materials science. In particular, its chemical stability and impermeability make it a promising protective membrane. However, recent investigations reveal that single layer graphene...... cannot be used as a barrier in the long run, due to galvanic corrosion phenomena arising when oxygen or water penetrate through graphene cracks or domain boundaries. Here, we overcome this issue by using a multilayered (ML) graphene coating. Our lab- as well as industrial-scale tests demonstrate that ML...... graphene can effectively protect Ni in harsh environments, even after long term exposure. This is made possible by the presence of a high number of graphene layers, which can efficiently mask the cracks and domain boundaries defects found in individual layers of graphene. Our findings thus show...

  8. Statistical optimization of microencapsulation process for coating of magnesium particles with Viton polymer

    Energy Technology Data Exchange (ETDEWEB)

    Pourmortazavi, Seied Mahdi, E-mail: pourmortazavi@yahoo.com [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of); Babaee, Saeed; Ashtiani, Fatemeh Shamsi [Faculty of Chemistry & Chemical Engineering, Malek Ashtar University of Technology, Tehran (Iran, Islamic Republic of)

    2015-09-15

    Graphical abstract: - Highlights: • Surface of magnesium particles was modified with Viton via solvent/non-solvent method. • FT-IR, SEM, EDX, Map analysis, and TG/DSC techniques were employed to characterize the coated particles. • Coating process factors were optimized by Taguchi robust design. • The importance of coating conditions on resistance of coated magnesium against oxidation was studied. - Abstract: The surface of magnesium particles was modified by coating with Viton as an energetic polymer using solvent/non-solvent technique. Taguchi robust method was utilized as a statistical experiment design to evaluate the role of coating process parameters. The coated magnesium particles were characterized by various techniques, i.e., Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and thermogravimetry (TG), and differential scanning calorimetry (DSC). The results showed that the coating of magnesium powder with the Viton leads to a higher resistance of metal against oxidation in the presence of air atmosphere. Meanwhile, tuning of the coating process parameters (i.e., percent of Viton, flow rate of non-solvent addition, and type of solvent) influences on the resistance of the metal particles against thermal oxidation. Coating of magnesium particles yields Viton coated particles with higher thermal stability (632 °C); in comparison with the pure magnesium powder, which commences oxidation in the presence of air atmosphere at a lower temperature of 260 °C.

  9. Coating materials

    International Nuclear Information System (INIS)

    Ozeki, Takao; Kimura, Tadashi; Kobayashi, Juichi; Maeda, Yutaka; Nakamoto, Hideo.

    1969-01-01

    A non-solvent type coating material composition is provided which can be hardened by irradiation with active energy, particularly electron beams, using a composition which contains 10%-100% of a radically polymerizable low molecular compound (A), (hereafter called an oligomer), having at least two vinyl radicals in one molecule. These compositions have a high degree of polymerization and characteristics equivalent to thermosetting acrylic or amino alkyd resin. The oligomer (A) is produced by reacting an epoxy-containing vinyl monomer with saturated polycarboxylic acids or anhydrides. In one embodiment, 146 parts by weight of adipic acid and 280 parts of glycidyl methacrylate ester undergo addition reaction in the presence of a polymerization-inhibitor and a catalyst at 90 0 C for 6 hours to produce an oligomer having a fiberous divinyl construction. The coating composition utilizes this oligomer in the forms of (I-1), a whole oligomer; (I-2), 0%-90% of this oligomer and 90%-10% of a vinyl monomer containing at least 30% of (meth) acrylic monomer; (I-3), 10%-90% of such oligomer and 90%-10% of other monomers containing at least two vinyl radicals in one molecule; (I-4), a mixture of (I-2) and (I-3) in proportion of 1/9 to 9/1, and (I-5), above four compositions each containing 50% or less unsaturated polyester or drying oil having 500-5,000 molecules or a drying oil-modified alkyd resin having 500-5,000 molecules. Four examples are given. (Iwakiri, K.)

  10. A drop penetration method to measure powder blend wettability.

    Science.gov (United States)

    Wang, Yifan; Liu, Zhanjie; Muzzio, Fernando; Drazer, German; Callegari, Gerardo

    2018-03-01

    Water wettability of pharmaceutical blends affects important quality attributes of final products. We investigate the wetting properties of a pharmaceutical blend lubricated with Magnesium Stearate (MgSt) as a function of the mechanical shear strain applied to the blend. We measure the penetration dynamics of sessile drops deposited on slightly compressed powder beds. We consider a blend composed of 9% Acetaminophen 90% Lactose and 1% MgSt by weight. Comparing the penetration time of water and a reference liquid Polydimethylsiloxane (silicon oil) we obtain an effective cosine of the contact angle with water, based on a recently developed drop penetration method. We repeat the experiments for blends exposed to increasing levels of shear strain and demonstrate a significant decrease in water wettability (decrease in the cosine of the contact angle). The results are consistent with the development of a hydrophobic film coating the powder particles as a result of the increased shear strain. Finally, we show that, as expected dissolution times increase with the level of shear strain. Therefore, the proposed drop penetration method could be used to directly assess the state of lubrication of a pharmaceutical blend and act as a quality control on powder blend attributes before the blend is tableted. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Preparation of high-quality ultrathin transmission electron microscopy specimens of a nanocrystalline metallic powder.

    Science.gov (United States)

    Riedl, Thomas; Gemming, Thomas; Mickel, Christine; Eymann, Konrad; Kirchner, Alexander; Kieback, Bernd

    2012-06-01

    This article explores the achievable transmission electron microscopy specimen thickness and quality by using three different preparation methods in the case of a high-strength nanocrystalline Cu-Nb powder alloy. Low specimen thickness is essential for spatially resolved analyses of the grains in nanocrystalline materials. We have found that single-sided as well as double-sided low-angle Ar ion milling of the Cu-Nb powders embedded into epoxy resin produced wedge-shaped particles of very low thickness (coating on the sections consisting of epoxy deployed as the embedding material and considerable nanoscale thickness variations. Copyright © 2011 Wiley Periodicals, Inc.

  12. Investigation of pressing of molybdenum powder compacts

    International Nuclear Information System (INIS)

    Mymrin, S.A.; Kuznetsov, V.Eh.; Yampol'skij, M.L.; Leonov, S.A.; Mikhridinov, R.M.; Korzukhin, V.A.

    1990-01-01

    Results of an experimental investigation into pressing of compacts of MCh type molybdenum powders using the industrial equipment are presented. To measure the density of powder molybdenum billets a radioisotopic density meter with cesium-137 is used as radioactive gamma radiation source. The dependence of the produced billet density on the specific compacting pressure at different values of the powder bulk density is ascertained

  13. MECHANICS OF DYNAMIC POWDER COMPACTION PROCESS

    OpenAIRE

    Nurettin YAVUZ

    1996-01-01

    In recent years, interest in dynamic compaction methods of metal powders has increased due to the need to improve compaction properties and to increase production rates of compacts. In this paper, review of dynamic and explosive compaction of metal powders are given. An attempt is made to get a better understanding of the compaction process with the mechanicis of powder compaction.

  14. 21 CFR 73.2645 - Aluminum powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements of...

  15. 21 CFR 73.1645 - Aluminum powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum. It...

  16. 21 CFR 73.2647 - Copper powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Copper powder. 73.2647 Section 73.2647 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity and specifications to the requirements of § 73...

  17. Effect of CeO2 on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding

    OpenAIRE

    Chen, Tao; Liu, Defu; Wu, Fan; Wang, Haojun

    2017-01-01

    To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO2 powders as the basic pre-placed materials. A certain amount of CeO2 powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO2 additive on the ph...

  18. Metal-Matrix Hardmetal/Cermet Reinforced Composite Powders for Thermal Spray

    Directory of Open Access Journals (Sweden)

    Dmitri GOLJANDIN

    2012-03-01

    Full Text Available Recycling of materials is becoming increasingly important as industry response to public demands, that resources must be preserved and environment protected. To produce materials competitive in cost with primary product, secondary producers have to pursue new technologies and other innovations. For these purposes different recycling technologies for composite materials (oxidation, milling, remelting etc are widely used. The current paper studies hardmetal/cermet powders produced by mechanical milling technology. The following composite materials were studied: Cr3C2-Ni cermets and WC-Co hardmetal. Different disintegrator milling systems for production of powders with determined size and shape were used. Chemical composition of produced powders was analysed.  To estimate the properties of recycled hardmetal/cermet powders, sieving analysis, laser granulometry and angularity study were conducted. To describe the angularity of milled powders, spike parameter–quadric fit (SPQ was used and experiments for determination of SPQ sensitivity and precision to characterize particles angularity were performed. Images used for calculating SPQ were taken by SEM processed with Omnimet Image Analyser 22. The graphs of grindability and angularity were composed. Composite powders based on Fe- and Ni-self-fluxing alloys for thermal spray (plasma and HVOF were produced. Technological properties of powders and properties of thermal sprayed coatings from studied powders were investigated. The properties of spray powders reinforced with recycled hardmetal and cermet particles as alternatives for cost-sensitive applications were demonstrated.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1348

  19. Development and evaluation of suspension plasma sprayed yttria stabilized zirconia coatings as thermal barriers

    Science.gov (United States)

    van Every, Kent J.

    The insulating effects from thermal barrier coatings (TBCs) in gas turbine engines allow for increased operational efficiencies and longer service lifetimes. Consequently, improving TBCs can lead to enhanced gas turbine engine performance. This study was conducted to investigate if yttria-stabilized zirconia (YSZ) coatings, the standard industrial choice for TBCs, produced from nano-sized powder could provide better thermal insulation than current commericial YSZ coatings generated using micron-sized powders. The coatings for this research were made via the recently developed suspension plasma spraying (SPS) process. With SPS, powders are suspended in a solvent containing dispersing agents; the suspension is then injected directly into a plasma flow that evaporates the solvent and melts the powder while transporting it to the substrate. Although related to the industrial TBC production method of air plasma spraying (APS), SPS has two important differences---the ability to spray sub-micron diameter ceramic particles, and the ability to alloy the particles with chemicals dissolved in the solvent. These aspects of SPS were employed to generate a series of coatings from suspensions containing ˜100 nm diameter YSZ powder particles, some of which were alloyed with neodymium and ytterbium ions from the solvent. The SPS coatings contained columnar structures not observed in APS TBCs; thus, a theory was developed to explain the formation of these features. The thermal conductivity of the coatings was tested to evaluate the effects of these unique microstructures and the effects of the alloying process. The results for samples in the as-sprayed and heat-treated conditions were compared to conventional YSZ TBCs. This comparison showed that, relative to APS YSZ coatings, the unalloyed SPS samples typically exhibited higher as-sprayed and lower heat-treated thermal conductivities. All thermal conductivity values for the alloyed samples were lower than conventional YSZ TBCs

  20. Electrocurtain coating process for coating solar mirrors

    Science.gov (United States)

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  1. Development of Cr3C2-25(Ni20Cr) nanostructured coatings

    International Nuclear Information System (INIS)

    Cunha, Cecilio Alvares da

    2012-01-01

    This study is divided in two parts. The first part is about the preparation of nanostructured Cr 3 C 2 -25(Ni20Cr) powders by high energy milling followed by characterization of the milled and the as received powder. Analyses of some of the data obtained were done using a theoretical approach. The second part of this study is about the preparation and characterization of coatings prepared with the nanostructured as well as the as received Cr 3 C 2 -25(Ni20Cr) powders. The high temperature erosion-oxidation (E-O) behavior of the coatings prepared with the two types of powders has been compared based on a technological approach. The average crystallite size of the Cr 3 C 2 -25(Ni20Cr) powder decreased rapidly from 145 nm to 50 nm in the initial stages of milling and thereafter decreased slowly to a steady state value of around 10 nm with further increase in milling time. This steady state corresponds to the beginning of a dynamic recovery process. The maximum lattice strain (ε = 1,17%) was observed in powders milled for 16 hours, and this powders critical crystallite size was 28 nm. In contrast, the lattice parameter attained a minimum for powders milled for 16 hours. Upon reaching the critical crystallite size, the dislocation density attained a steady state regime and all plastic deformation introduced in the material there after was in the form of events occurring at the grain boundaries, due mainly to grain boundary sliding. The deformation energy stored in the crystal lattice of the Cr 3 C 2 -25(Ni20Cr) powders milled for different times was determined from enthalpy variation measurements. These results indicated that the maximum enthalpy variation (δH = 722 mcal) also occurred for powders milled for 16 hours. In a similar manner, the maximum specific heat variation (δC p = 0,278 cal/gK) occurred for powders milled for 16 hours. The following mechanical properties of Cr 3 C 2 -25(Ni20Cr) coatings prepared using the HVOF thermal spray process were determined

  2. New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

    NARCIS (Netherlands)

    Budding, A.; Vaneker, Thomas H.J.

    2013-01-01

    In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of

  3. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine equivalent...

  4. Effect of CeO₂ on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding.

    Science.gov (United States)

    Chen, Tao; Liu, Defu; Wu, Fan; Wang, Haojun

    2017-12-31

    To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO₂ powders as the basic pre-placed materials. A certain amount of CeO₂ powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO₂ additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO₂ on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO₂. With the increase of CeO₂ additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO₂ additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings.

  5. Effect of CeO2 on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding

    Science.gov (United States)

    Wang, Haojun

    2017-01-01

    To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO2 powders as the basic pre-placed materials. A certain amount of CeO2 powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO2 additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO2 on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO2. With the increase of CeO2 additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO2 additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings. PMID:29301218

  6. Investigation of calcium phosphate coatings for biomedical applications

    International Nuclear Information System (INIS)

    Yusof Abdullah; Idris Besar; Muhammad Jamal Md Isa; Mohamad Abd Razak; Hyzan Mohd Yusof

    1999-01-01

    Calcium phosphate is the main constituent of our bone and tooth minerals. The use of this bioactive material for coating implant such as artificial joint prosthesis, therefore, can promote biological fixation and enhance biocompatibility. Our initial work has been focused on the evaluation of experimental conditions of coating preparation and the effects of post-deposition calcium phosphate coatings on stainless steel substrates. The coating layers were produced by the precipitation technique and coatings were carried out in sol-gel by the dipping method. For comparison purposes a wet method was used to obtain a fine calcium phosphate ceramic powder for fabrication of microcrystal suspension used as a coating material. Scanning electron microscopy (SEM), energy dispersive microanalysis (EDS), energy dispersive x-ray fluorescence (EDXRF) and x-ray diffraction (XRD) were used to characterise the morphology, chemical composition and structure of the coatings. The results showed that the dip coating of stainless steel substrates using viscous solutions lead to the formation of porous calcium phosphate layers. These results suggested that fabrication of bioactive calcium phosphate coatings using this route offers significant advantages over the currently used methods due to considerably lower temperature process involved and may produce better result for substrates with complex shapes

  7. Wrinkling of solidifying polymeric coatings

    Science.gov (United States)

    Basu, Soumendra Kumar

    2005-07-01

    In coatings, wrinkles are viewed as defects or as desired features for low gloss, and texture. In either case, discovering the origin of wrinkles and the conditions that lead to their formation is important. This research examines what wrinkling requires and proposes a mechanism to explain the observations. All curing wrinkling coatings contain multi-functional reactants. Upon curing, all develop a depth-wise gradient in solidification that result in a cross-linked elastic skin atop a viscous bottom layer. It is hypothesized that compressive stress develops in the skin when liquid below diffuses up into the skin. High enough compressive stress buckles the skin to produce wrinkles. The hypothesis is substantiated by experimental and theoretical evidences. Effects of various application and compositional parameters on wrinkle size in a liquid-applied acrylic coating and a powder-applied epoxy coating were examined. All three components, namely resin, cross-linker and catalyst blocked with at least equimolar volatile blocker, proved to be required for wrinkling. The wrinkling phenomenon was modeled with a theory that accounts for gradient generation, cross-linking reaction and skinning; predictions compared well with observations. Two-layer non-curing coatings that have a stiff elastic layer atop a complaint elastic bottom layer wrinkled when the top layer is compressed. The top layer was compressed by either moisture absorption or differential thermal expansion. Experimental observations compared well with predictions from a theory based on force balance in multilayer systems subjected to differential contraction or expansion. A model based on the Flory-Rehner free energy of a constrained cross-linked gel was constructed that predicts the compressive stress generated in a coating when it absorbs solvent. Linear stability analysis predicts that when a compressed elastic layer is attached atop a viscous layer, it is always unstable to buckles whose wavelength exceeds a

  8. Separation of UO2 powder

    International Nuclear Information System (INIS)

    Ristic, M.M.

    1962-01-01

    This report deals with theoretical approach to separation process and describes the constructed separator with liquid medium. The separator was calibrated and tested with Al 3 O 3 and UO 2 . it has been concluded that it can be used for separation of powders with sufficient accuracy if the separation is performed for a longer period of time. The separated fractions were characterised by microscopic method and the UO 2 fraction additionally by sedimentation method

  9. Manufacture of uranium dioxide powder

    International Nuclear Information System (INIS)

    Becker, M.

    1976-01-01

    Uranium dioxide powder is prepared by the AUC (ammonium uranyl carbonate) method. Supplementing the known process steps, the AUC, after separation from the mother liquor, is washed with an ammonium hydrogen carbonate or an NH 4 OH solution and is subsequently post-treated with a liquid which reduces the surface tension of the residual water in an AUC. Such a liquid is, for instance, alcohol

  10. Milling Behavior of Matrix Graphite Powders with Different Binder Materials in HTGR Fuel Element Fabrication: I. Variation in Particle Size Distribution

    International Nuclear Information System (INIS)

    Lee, Young Woo; Cho, Moon Sung

    2011-01-01

    The fuel element for HTGR is manufactured by mixing coated fuel particles with matrix graphite powder and forming into either pebble type or cylindrical type compacts depending on their use in different HTGR cores. The coated fuel particle, the so-called TRISO particle, consists of 500-μm spherical UO 2 particles coated with the low density buffer Pyrolytic Carbon (PyC) layer, the inner and outer high density PyC layer and SiC layer sandwiched between the two inner and outer PyC layers. The coated TRISO particles are mixed with a matrix graphite powder properly prepared and pressed into a spherical shape or a cylindrical compact finally heat-treated at about 1900 .deg. C. These fuel elements can have different sizes and forms of compact. The basic steps for manufacturing a fuel element include preparation of graphite matrix powder, overcoating the fuel particles, mixing the fuel particles with a matrix powder, carbonizing green compact, and the final high-temperature heat treatment of the carbonized fuel compact. In order to develop a fuel compact fabrication technology, it is important to develop a technology to prepare the matrix graphite powder (MGP) with proper characteristics, which has a strong influence on further steps and the material properties of fuel element. In this work, the milling behavior of matrix graphite powder mixture with different binder materials and their contents was investigated by analyzing the change in particle size distribution with different milling time

  11. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  12. Bioceramic coating of hydroxyapatite on titanium substrate with Nd-YAG laser

    International Nuclear Information System (INIS)

    Cheng, Gary J.; Pirzada, Daniel; Cai, M.; Mohanty, Pravansu; Bandyopadhyay, Amit

    2005-01-01

    The ability to bond to bone tissue is a unique property of bioactive ceramics. Hydroxyapatite (HAp) is one of the potential bioceramics candidates due to its superior bio-compatibility. Significant effort has been devoted to coat HAp ceramics on metallic substrates. Most of these processes, such as ion-beam sputter coating, thermal spraying, and flame spraying, are high temperature line of sight processes, which suffer from undesirable phase formation and weak metal/HAP bonding strength. This paper presents a unique process to coat HAp powders on titanium substrates at low temperature and enhance the coating/substrate interface by laser surface engineering. Nd-YAG laser transmits HAp powders and the laser power is absorbed by titanium substrate to produce a thin layer of molten region. During coating process, HAp powders are kept at low temperature before they are entrapped in metallic layer. Scanning electron microscope (SEM) was used to investigate the microstructure of coating; the chemical composition of the coating is determined by energy dispersive spectrometry (EDS). Mechanical properties of the interface between coating and Ti substrate were investigated by nanoindentation

  13. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    Directory of Open Access Journals (Sweden)

    Qijun Li

    Full Text Available Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process. Keywords: Powder metallurgy, Nb-Ti based alloy, Porous material, Mechanical alloying, Plasma spheroidizing, Solidification microstructure

  14. MnCo{sub 2}O{sub 4} spinel chromium barrier coatings for SOFC interconnect by HVOF

    Energy Technology Data Exchange (ETDEWEB)

    Lagerbom, J.; Varis, T.; Pihlatie, M.; Himanen, O.; Saarinen, V.; Kiviaho, J.; Turunen, E. [VTT Technical Research Centre of Finland, Espoo (Finland); Puranen, J. [Tampere Univ. of Technology (Finland). Inst. of Materials Science

    2010-07-01

    Chromia released from steel parts used for interconnect plates by evaporation and condensation can quickly degrade the cell (cathode) performance in solid oxide fuel cell SOFC. Coatings on top of the IC plate can work as a chromium evaporation barrier. The coating material should have good electrical conductivity, high temperature stability and nearly the same coefficient of thermal expansion as the cell materials. One candidate for the coating material is MnCo{sub 2}O{sub 4} spinel because of its suitable properties. High velocity oxy fuel (HVOF) spraying was used for the coating application on Crofer 22 APU steel samples. Using commercial and self made spray dried powders together with an HV2000 spray gun it was possible to successfully manufacture, well adhering, dense and reasonably uniform coatings. The samples were tested in oxidation exposure tests in air followed by post analysis in SEM. Powders and coatings microstructures are presented here, both before and after exposure. It was found out that together with spraying parameters the powder characteristics used influence clearly to the coating quality. Especially as very thin coatings was aimed with dense structure fine powders was found to be essential. (orig.)

  15. Study of water retention capacity in mortars with the incorporation of exhaust powder

    International Nuclear Information System (INIS)

    Pereira, Helena Ravache Samy; Valentina, Luiz Veriano Oliveira Dalla; Priscila Warch

    2011-01-01

    The purpose of this study is to suggest the incorporation of exhaust powder waste in mortars for laying and coating walls and ceilings, to evaluate the representative proportions through mixture design, aiming for a satisfactory performance of the analyzed property and the water retention capacity. In the experimental procedure ten mixtures were performed with consistence index of 230±10mm. The surface response generated showed a water retention capacity in mortar varying from 88% to 95%, which could be classified as normal and high. In relation to the water retention, the incorporation of foundry exhaust powder waste in the studied proportions is viable in mortars for laying and coating walls and ceilings. (author)

  16. Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

    Science.gov (United States)

    Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

    2015-08-01

    Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation.

  17. 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...

  18. Flow coating apparatus and method of coating

    Science.gov (United States)

    Hanumanthu, Ramasubrahmaniam; Neyman, Patrick; MacDonald, Niles; Brophy, Brenor; Kopczynski, Kevin; Nair, Wood

    2014-03-11

    Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.

  19. A novel process for production of spherical PBT powders and their processing behavior during laser beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Jochen, E-mail: jochen.schmidt@fau.de; Sachs, Marius; Fanselow, Stephanie; Wirth, Karl-Ernst; Peukert, Wolfgang [Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Cauerstr. 4, D-91058 Erlangen (Germany); Zhao, Meng; Wudy, Katrin; Drexler, Maximilian; Drummer, Dietmar [Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Polymer Technology, Am Weichselgarten 9, D-91058 Erlangen (Germany)

    2016-03-09

    Additive manufacturing processes like laser beam melting of polymers are established for production of prototypes and individualized parts. The transfer to other areas of application and to serial production is currently hindered by the limited availability of polymer powders with good processability. Within this contribution a novel process route for the production of spherical polymer micron-sized particles of good flowability has been established and applied to produce polybutylene terephthalate (PBT) powders. Moreover, the applicability of the PBT powders in selective laser beam melting and the dependencies of process parameters on device properties will be outlined. First, polymer micro particles are produced by a novel wet grinding method. To improve the flowability the produced particles the particle shape is optimized by rounding in a heated downer reactor. A further improvement of flowability of the cohesive spherical PBT particles is realized by dry coating. An improvement of flowability by a factor of about 5 is achieved by subsequent rounding of the comminution product and dry-coating as proven by tensile strength measurements of the powders. The produced PBT powders were characterized with respect to their processability. Therefore thermal, rheological, optical and bulk properties were analyzed. Based on these investigations a range of processing parameters was derived. Parameter studies on thin layers, produced in a selective laser melting system, were conducted. Hence appropriate parameters for processing the PBT powders by laser beam melting, like building chamber temperature, scan speed and laser power have been identified.

  20. A novel process for production of spherical PBT powders and their processing behavior during laser beam melting

    International Nuclear Information System (INIS)

    Schmidt, Jochen; Sachs, Marius; Fanselow, Stephanie; Wirth, Karl-Ernst; Peukert, Wolfgang; Zhao, Meng; Wudy, Katrin; Drexler, Maximilian; Drummer, Dietmar

    2016-01-01

    Additive manufacturing processes like laser beam melting of polymers are established for production of prototypes and individualized parts. The transfer to other areas of application and to serial production is currently hindered by the limited availability of polymer powders with good processability. Within this contribution a novel process route for the production of spherical polymer micron-sized particles of good flowability has been established and applied to produce polybutylene terephthalate (PBT) powders. Moreover, the applicability of the PBT powders in selective laser beam melting and the dependencies of process parameters on device properties will be outlined. First, polymer micro particles are produced by a novel wet grinding method. To improve the flowability the produced particles the particle shape is optimized by rounding in a heated downer reactor. A further improvement of flowability of the cohesive spherical PBT particles is realized by dry coating. An improvement of flowability by a factor of about 5 is achieved by subsequent rounding of the comminution product and dry-coating as proven by tensile strength measurements of the powders. The produced PBT powders were characterized with respect to their processability. Therefore thermal, rheological, optical and bulk properties were analyzed. Based on these investigations a range of processing parameters was derived. Parameter studies on thin layers, produced in a selective laser melting system, were conducted. Hence appropriate parameters for processing the PBT powders by laser beam melting, like building chamber temperature, scan speed and laser power have been identified.

  1. The oxidation behaviour of sprayed MCrAlY coatings

    International Nuclear Information System (INIS)

    Brandl, W.; Toma, D.; Krueger, J.

    1996-01-01

    Turbine blades are protected against high temperature oxidation by thermal barrier coating (TBC) systems, which consist of a ceramic top coating (ZrO 2 /Y 2 O 3 ) and a metal bond coating (MCrAlY, M = Ni, Co). At high temperatures and under oxidative conditions, between the MCrAlY and the ceramic top coating an oxide scale is formed, which protects the metal against further oxidation. The oxidation behaviour of the thermally sprayed MCrAlY is influenced by the coating process and the composition of the metal alloys. This work is concerned with the isothermal oxidation behaviour of vacuum plasma sprayed (VPS) MCrAlY coatings. The MCrAlY powders used have different aluminium contents: 8 and 12 wt.%. The MCrAlY specimens are oxidized at 1050 C in air as well as in helium with 1% O 2 and the oxidation kinetics are determined thermogravimetrically. The microstructure, morphology and thickness of the oxide scales formed are characterized by metallography, SEM, TEM and XRD. After short time oxidation (6 h) θ-Al 2 O 3 is the main constituent of the oxide scale. Exposure times of 500 h and more lead to oxide scales consisting of α-Al 2 O 3 . Moreover, after a long time oxidation, Cr 2 O 3 and CoO (CoO on the coatings with 8 wt.% Al) are formed. The oxidation rates of both MCrAlY coatings are the same. Beneath the oxide scale an Al-depleted zone is formed and this zone is considerably thicker within the coating with 8 wt.% Al, because the amount of β-NiAl phase in this coating is lower than that in the coating with 12 wt.% Al. The oxide scale formed in He-1% O 2 consists of α-Al 2 O 3 and Cr 2 O 3 on both MCrAlY coatings. (orig.)

  2. WC-Co coatings deposited by the electro-thermal chemical spray method

    Energy Technology Data Exchange (ETDEWEB)

    Zhitomirsky, V.N. [Tel Aviv Univ. (Israel). Faculty of Engineering; Wald, S.; Rabani, L.; Zoler, D. [Propulsion Physics Division, SOREQ NRC, 81800, Yavne (Israel); Factor, M.; Roman, I. [School of Applied Sciences, The Hebrew University, 91904, Jerusalem (Israel); Cuperman, S.; Bruma, C. [School of Physics and Astronomy, Tel-Aviv University, 69978, Tel-Aviv (Israel)

    2000-10-02

    A novel thermal spray technology - an electro-thermal chemical spray (ETCS) for producing hard coatings is presented. The experimental coating apparatus consists of a machine gun barrel, a cartridge containing the coating material in powder form, a solid propellant, and a plasma ignition system. The plasma ignition system produces plasma in pulsed mode to ignite the solid propellant. On ignition, the drag force exerted by the combustion gases accelerates the powder particles towards the substrate. Using the ETCS technique, the process of single-shot WC-Co coating deposition on stainless steel substrate was studied. The influence of process parameters (plasma energy, mass of the solid propellant and the coated powder, distance between the gun muzzle and the substrate) on the coating structure and some of its properties were investigated. It was shown that ECTS technique effectively deposited the WC-Co coating with deposition thicknesses of 100-200 {mu}m per shot, while deposition yield of {proportional_to}70% was attained. The WC-Co coatings consisted of carbide particles distributed in amorphous matrix. The powder particle velocity was found to depend on the solid propellant mass and was weakly dependent on the plasma energy, while the particle processing temperature was strongly dependent on the plasma energy and almost independent of the solid propellant mass. Whilst increasing the solid propellant mass from 5 to 7 g, the deposition rate and yield correspondingly increased. When increasing the plasma energy, the temperature of the powder particles increased, the average carbide particle size decreased and their shape became more rounded. The deposition yield and microhardness at first increased and then achieved saturation by increasing the plasma energy. (orig.)

  3. Phase evolution in calcium phosphate coatings obtained by in situ laser cladding

    International Nuclear Information System (INIS)

    Lv Xiaowei; Lin Xin; Hu Jiang; Gao Bo; Huang Weidong

    2012-01-01

    Calcium phosphate coating was fabricated by in situ laser cladding using mixed powders of CaCO 3 and CaHPO 4 , which presented a complex phase constitution since the reactions between CaCO 3 and CaHPO 4 would produce not only hydroxyapatite (HA) in the coating, but also other phases, such as Ca 4 (PO 4 ) 2 O (TTCP) and α-Ca 3 (PO 4 ) 2 (α-TCP). In order to realize the control of the phase constitution, the effects of the Ca/P molar ratio of mixed powders, laser power, scanning velocity and heat treatment on the phase constitution of the coatings were investigated through X-ray diffraction analysis. It is found that the variation of the Ca/P molar ratio of the mixed powders, laser power and scanning velocity can adjust, to a certain extent, the proportion of HA, α-TCP, and TTCP in the coating. However, the α-TCP and TTCP cannot be eliminated from the coating due to the intrinsic high cooling rate of the laser melt pool during laser cladding. By suitable post heat treatment, the TTCP and α-TCP in the coating can be partially or completely transformed into HA. Therefore, HA coating or coatings with desirable proportion of HA, α-TCP and TTCP can be obtained by in situ laser cladding plus post heat treatment. - Highlights: ► The phase constitution varies with the Ca/P molar ratio of the mixed powders of CaCO 3 and CaHPO 4 . ► High laser powder and scanning velocity are disadvantages for the synthesis of HA. ► Heat treatment with furnace cooling can make α-TCP and TTCP transform into HA.

  4. A Study on Silicide Coatings as Diffusion barrier for U-7Mo Dispersion Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Won, Ju Jin; Kim, Sung Hwan; Lee, Kyu Hong; Jeong, Yong Jin; Kim, Ki Nam; Park, Jong Man; Lee, Chong Tak [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Gamma phase U-Mo alloys are regarded as one of the promising candidates for advanced research reactor fuel when it comes to the irradiation performance. However, it has been reported that interaction layer formation between the UMo alloys and Al matrix degrades the irradiation performance of U-Mo dispersion fuel. The excessive interaction between the U-Mo alloys and their surrounding Al matrix lead to excessive local swelling called 'pillowing'. For this reason, KAERI suggested several remedies such as alloying U-Mo with Al matrix with Si. In addition, silicide or nitride coatings on the surface of U-Mo particles have also been proposed to hinder the growth of the interaction layer. In this study, centrifugally atomized U-7Mo alloy powders were coated with silicide layers at 900 .deg. C for 1hr. U-Mo alloy powder was mixed with MoSi{sub 2}, Si and ZrSi{sub 2} powders and subsequently heat-treated to form uranium-silicide coating layers on the surface of U-Mo alloy particles. Silicide coated U-Mo powders and characterized using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and X-ray diffractometer (XRD). The ZrSi{sub 2} coating layers has a thickness of about 1∼ 2μm. The surface of a silicide coated particle was very rough and silicide powder attached to the surface of the coating layer. 3. The XRD analysis of the coating layers showed that, they consisted of compounds such as U3Si{sub 2}, USi{sub 2}.

  5. Identifying the optimal HVOF spray parameters to attain minimum porosity and maximum hardness in iron based amorphous metallic coatings

    Directory of Open Access Journals (Sweden)

    S. Vignesh

    2017-04-01

    Full Text Available Flow based Erosion – corrosion problems are very common in fluid handling equipments such as propellers, impellers, pumps in warships, submarine. Though there are many coating materials available to combat erosion–corrosion damage in the above components, iron based amorphous coatings are considered to be more effective to combat erosion–corrosion problems. High velocity oxy-fuel (HVOF spray process is considered to be a better process to coat the iron based amorphous powders. In this investigation, iron based amorphous metallic coating was developed on 316 stainless steel substrate using HVOF spray technique. Empirical relationships were developed to predict the porosity and micro hardness of iron based amorphous coating incorporating HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance. Response surface methodology (RSM was used to identify the optimal HVOF spray parameters to attain coating with minimum porosity and maximum hardness.

  6. Detection of thermally grown oxides in thermal barrier coatings by nondestructive evaluation

    Science.gov (United States)

    Fahr, A.; Rogé, B.; Thornton, J.

    2006-03-01

    The thermal-barrier coatings (TBC) sprayed on hot-section components of aircraft turbine engines commonly consist of a partially stabilized zirconia top-coat and an intermediate bond-coat applied on the metallic substrate. The bond-coat is made of an aluminide alloy that at high engine temperatures forms thermally grown oxides (TGO). Although formation of a thin layer of aluminum oxide at the interface between the ceramic top-coat and the bond-coat has the beneficial effect of protecting the metallic substrate from hot gases, oxide formation at splat boundaries or pores within the bond-coat is a source of weakness. In this study, plasma-sprayed TBC specimens are manufactured from two types of bond-coat powders and exposed to elevated temperatures to form oxides at the ceramic-bond-coat boundary and within the bond-coat. The specimens are then tested using nondestructive evaluation (NDE) and destructive metallography and compared with the as-manufactured samples. The objective is to determine if NDE can identify the oxidation within the bond-coat and give indication of its severity. While ultrasonic testing can provide some indication of the degree of bond-coat oxidation, the eddy current (EC) technique clearly identifies severe oxide formation within the bond-coat. Imaging of the EC signals as the function of probe location provides information on the spatial variations in the degree of oxidation, and thereby identifies which components or areas are prone to premature damage.

  7. Preparation and Characterization of Plasma-Sprayed Ultrafine Chromium Oxide Coatings

    International Nuclear Information System (INIS)

    Lin Feng; Jiang Xianliang; Yu Yueguang; Zeng Keli; Ren Xianjing; Li Zhenduo

    2007-01-01

    Ultrafine chromium oxide coatings were prepared by plasma spraying with ultrafine feedstock. Processing parameters of plasma spraying were optimized. Optical microscope (OM) was used to observe the microstructure of the ultrafine chromium oxide coatings. Scanning electron microscopy (SEM) was used to observe the morphology and particle size of ultrafine powder feedstock as well as to examine the microstructure of the chromium oxide coating. In addition, hardness and bonding strength of the ultrafine chromium oxide coatings were measured. The results showed that the optimized plasma spraying parameters were suitable for ultrafine chromium oxide coating and the properties and microstructure of the optimized ultrafine chromium oxide coating were superior compared to conventional chromium oxide wear resistant coatings

  8. Optimization and Characterization of High Velocity Oxy-fuel Sprayed Coatings: Techniques, Materials, and Applications

    Directory of Open Access Journals (Sweden)

    Maria Oksa

    2011-09-01

    Full Text Available In this work High Velocity Oxy-fuel (HVOF thermal spray techniques, spraying process optimization, and characterization of coatings are reviewed. Different variants of the technology are described and the main differences in spray conditions in terms of particle kinetics and thermal energy are rationalized. Methods and tools for controlling the spray process are presented as well as their use in optimizing the coating process. It will be shown how the differences from the starting powder to the final coating formation affect the coating microstructure and performance. Typical properties of HVOF sprayed coatings and coating performance is described. Also development of testing methods used for the evaluation of coating properties and current status of standardization is presented. Short discussion of typical applications is done.

  9. Characterization of Powder Metallurgy Processed Pure Magnesium Materials for Biomedical Applications

    Czech Academy of Sciences Publication Activity Database

    Březina, M.; Minda, J.; Doležal, P.; Krystýnová, M.; Fintová, Stanislava; Zapletal, J.; Wasserbauer, J.; Ptáček, P.

    2017-01-01

    Roč. 7, č. 11 (2017), č. článku 461. ISSN 2075-4701 Institutional support: RVO:68081723 Keywords : magnesium * powder metallurgy * cold pressing * hot pressing * EIS (Electrochemical impedance spectroscopy) * three-point bending test * corrosion Subject RIV: JK - Corrosion ; Surface Treatment of Materials OBOR OECD: Coating and films Impact factor: 1.984, year: 2016 http://www.mdpi.com/2075-4701/7/11/461

  10. Study on coating layer of ceramic materials for SFR fuel slugs

    International Nuclear Information System (INIS)

    Song, Hoon; Kim, Jonghwan; Kim, Kihwan; Ko, Youngmo; Woo, Yoonmyung; Lee, Chanbock

    2013-01-01

    The plasma-sprayed coating can provide the crucible with a denser, more durable, coating layer, compared with the more friable coating layer formed by slurry-coating. Plasma-sprayed coatings are consolidated by mechanical interlocking of the molten particles impacting on the substrate and are dense by the heat applied by the plasma. The objective of this study is to develop a coating method and material for crucibles to prevent material interactions with the U-Zr/U-TRU-Zr fuels. Reducing these interactions will result in a fuel loss reduction. According to coating and U-Zr interaction results preformed in previous experience, Y 2 O 3 , TiC, and TaC coating materials were selected as promising coating materials Various combinations of coating conditions such as; coating thickness, double multi-layer coating methods were investigated to find the bonding effect on the substrate in pursuit of more effective ways to withstand the thermal stresses. To develop a coating method and material for crucibles to prevent material interactions with U-TRU-Zr fuels, the refractory coating was performed using vacuum plasma-sprayed method onto niobium rod. The various combinations of coating conditions such as; coating thickness, double multi-layer coating methods were investigated to find the bonding effect to withstand the thermal stress. Most of coating method samples did not maintain integrity in the U-Zr-RE melt because of the cracks or the microcracks of the coating layer, presumably formed from the thermal expansion difference. Only the double-layer coated rod with TaC and Y 2 O 3 powders, which is, which consists of vacuum plasma-sprayed TaC bond coating with the coating thickness of 100μm onto niobium rod and vacuum plasma-sprayed Y 2 O 3 coating with the coating thickness of 100μm on the top of the bond coating layer, survived the 2 cycles dipping test of U-Zr-RE melt this is likely caused by good adhesion of the TaC coating onto the niobium rod and the chemical inertness

  11. The influence of structural changes on electrical and magnetic characteristics of amorphous powder of the nixmoy alloy

    Directory of Open Access Journals (Sweden)

    Ribić-Zelenović Lenka

    2006-01-01

    Full Text Available Nickel and molybdenum alloy powder was electrodeposited on a titanium cathode from a NiSO4⋅7H2O and (NH46 Mo7O24⋅4H2O ammonium solution. The desired chemical composition, structure, size and shape of particles in the powder samples were achieved by an appropriate choice of electrolysis parameters (current density, composition and temperature of the solution, cathode material and electrolysis duration. Metal coatings form in the current density range 15 mA cm-2powders form. The chemical composition of powder samples depends on the current density of electrodeposition. The molybdenum content in the powder increases with the increase of current density (in the low current density range, while in the higher current density range the molybdenum content in the alloy decreases with the increase of the current density of deposition. Smaller sized particles form at higher current density. X-ray analysis, differential scanning calorimetric and measurements of the temperature dependence of electric resistance and magnetic permeability of the powder samples were all used to establish a predominantly amorphous structure of the powder samples formed at the current density of j≥70mA cm-2. The crystalline particle content in the powder samples increases with the decrease of the current density of deposition. Powder heating causes structural changes. The process of thermal stabilization of nickel and molybdenum amorphous powders takes place in the temperature interval from 463K to 573K and causes a decrease in electrical resistance and increase in magnetic permeability. The crystallization temperature depends on the value of current density of powder electrodeposition. Powder formed at j=180 mA cm-2 begins to crystallize at 573K, while the powder deposited at j=50 mA cm-2 begins to crystallize at 673K. Crystallization of the powder causes a decrease in electric resistivity and magnetic

  12. Characteristics Of The Porous Body Sintered By Nano-Sized Fe-Cr-Al Alloy Powder

    Directory of Open Access Journals (Sweden)

    Lee Su-In

    2015-06-01

    Full Text Available Porous metal with uniform honeycomb structure was successfully produced by sintering using Fe-Cr-Al nano powder, which was prepared by the pulsed wire evaporation (PWE in ethanol. Its process consisted of the several steps; 1 coating on the surface of polyurethane sponge with the liquid droplets generated from the ethanol-based slurry where the Fe-Cr-Al nano powders were uniformly dispersed, 2 heat treatment of debinding to remove the polyurethane sponge and 3 sintering of the porous green body formed by Fe-Cr-Al nano powders. The strut thickness of porous Fe-Cr-Al was increased by the increase of spraying times in ESP step. Also, The shrinkages and the oxidation resistance of the sintered porous body was increased with increase of sintering temperature. The optimal sintering temperature was shown to 1450°C in views to maximize the oxidation resistance and sinterability.

  13. Powder metallurgy of NiTi-alloys with defined shape memory properties

    International Nuclear Information System (INIS)

    Bram, M.; Ahmad-Khanlou, A.; Buchkremer, H.P.; Stoever, D.

    2001-01-01

    The aim of the present work is the development of fabrication processes for NiTi shape memory alloys by powder metallurgical means. The starting materials used were prealloyed powders as well as elemental powder mixtures. Three techniques seem to be very promising for shaping of NiTi compacts. Hot Isostatic Pressing (HIP) has been examined for the production of dense semi-finished components. A promising technique for the production of dense and porous coatings with an increased wear resistance is Vacuum Plasma Spraying (VPS). Metal Injection Moulding (MIM) is especially suitable for near-net shape fabrication of small components with a complex geometry considering that large numbers of units have to be produced for compensating high tool and process costs. Subsequently, thermal treatments are required to establish defined shape memory properties. The reproducibility and stability of the shape memory effect are main aspects thinking about a production of NiTi components in an industrial scale. (author)

  14. Preparation of Phosphonic Acid Functionalized Graphene Oxide-modified Aluminum Powder with Enhanced Anticorrosive Properties

    Science.gov (United States)

    He, Lihua; Zhao, Yan; Xing, Liying; Liu, Pinggui; Wang, Zhiyong; Zhang, Youwei; Liu, Xiaofang

    2017-07-01

    To improve the anticorrosive performance of aluminum powder, a common functional filler in polymer coatings, we report a novel method to prepare graphene oxide modified aluminum powder (GO-Al) using 3-aminoproplyphosphoic acid as "link" agent. The GO nanosheets were firstly functionalized with 3-aminoproplyphosphoic acid (APSA) by the reaction of amine groups of APSA and the epoxy groups of GO. Subsequently, a layer of GO nanosheets uniformly and tightly covered the surface of flaky aluminum particle though the strong linking strength between -PO(OH)2 functional groups of the modified GO and aluminum. The hydrogen evolution experiment suggests that the GO attached on the aluminum powder could effectively improve the anticorrosive performance of the pigments.

  15. Influence of the modes of laser cladding on bond strength and wear resistance of coatings

    Science.gov (United States)

    Birukov, V. P.; Tatarkin, D. Yu; Chriptovish, E. V.; Fichkov, A. A.

    2017-12-01

    The paper presents the results of metallographic studies and laboratory comparative tests on the adhesion strength of the coating to the substrate and abrasion on the scheme Brinell-Haworth cladding powder coatings on Nickel-based and samples of steel 40X. Strength of adhesion of the first coating layer with a hardness of HRC 38-42 was 400-480 MPa. It is shown that when the hardness of the deposited layer HRC 58-61 wear resistance of the coatings is higher than 40X steel in the normalized and improved in 10 and 4.6 times, respectively.

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

    Science.gov (United States)

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

    2017-11-01

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

  17. Roller compaction of moist pharmaceutical powders.

    Science.gov (United States)

    Wu, C-Y; Hung, W-L; Miguélez-Morán, A M; Gururajan, B; Seville, J P K

    2010-05-31

    The compression behaviour of powders during roller compaction is dominated by a number of factors, such as process conditions (roll speed, roll gap, feeding mechanisms and feeding speed) and powder properties (particle size, shape, moisture content). The moisture content affects the powder properties, such as the flowability and cohesion, but it is not clear how the moisture content will influence the powder compression behaviour during roller compaction. In this study, the effect of moisture contents on roller compaction behaviour of microcrystalline cellulose (MCC, Avicel PH102) was investigated experimentally. MCC samples of different moisture contents were prepared by mixing as-received MCC powder with different amount of water that was sprayed onto the powder bed being agitated in a rotary mixer. The flowability of these samples were evaluated in terms of the poured angle of repose and flow functions. The moist powders were then compacted using the instrumented roller compactor developed at the University of Birmingham. The flow and compression behaviour during roller compaction and the properties of produced ribbons were examined. It has been found that, as the moisture content increases, the flowability of moist MCC powders decreases and the powder becomes more cohesive. As a consequence of non-uniform flow of powder into the compaction zone induced by the friction between powder and side cheek plates, all produced ribbons have a higher density in the middle and lower densities at the edges. For the ribbons made of powders with high moisture contents, different hydration states across the ribbon width were also identified from SEM images. Moreover, it was interesting to find that these ribbons were split into two halves. This is attributed to the reduction in the mechanical strength of moist powder compacts with high moisture contents produced at high compression pressures. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  18. PIXE analysis of powdered milk

    International Nuclear Information System (INIS)

    Hallak, A.B.

    1983-01-01

    An accelerator-based study, using proton-induced x-ray emission (PIXE) was performed on four full-cream and four half-cream brands of powdered milk commonly consumed in Jordan. The elements detected in the samples are S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. The significance of some of these elements is discussed from the viewpoint of nutrition and also their effect on milk processing and dairy technology. The standard reference milk sample, A-11, which is distributed by IAEA was also examined, and the results for trace elements detected are compared with the values certified by IAEA. (author)

  19. Atomization process for metal powder

    International Nuclear Information System (INIS)

    Lagutkin, Stanislav; Achelis, Lydia; Sheikhaliev, Sheikhali; Uhlenwinkel, Volker; Srivastava, Vikas

    2004-01-01

    A new atomization process has been developed, which combines pressure and gas atomization. The melt leaves the pressure nozzle as a hollow thin film cone. After the pre-filming step, the melt is atomized by a gas stream delivered by a ring nozzle. The objectives of this investigation are to achieve a narrow size distribution and low specific gas consumption compared to conventional gas atomization techniques. Both lead to a higher efficiency and low costs. Tin and some alloys have been atomized successfully with this technique. The mass median diameters from different experiments are between 20 and 100 μm. Sieving analysis of the tin powder shows close particle size distributions

  20. High-productivity laser deposition welding using powder and wire. Final report of the project 'Higher efficiency of thermal coating plants by a combination of energy sources'; Hochproduktives Laser-Auftragschweissen mit Pulver und Draht. Ergebnisbericht zum Verbundvorhaben ''Wirkungsgradsteigerung thermischer Beschichtungsanlagen durch Energiequellenkombination''. SPRAYNERGY

    Energy Technology Data Exchange (ETDEWEB)

    Nowotny, Steffen (ed.)

    2013-05-01

    Excellent precision, maximum mechanical strength and selective properties of the generated coatings and 3D structures caused a breakthrough of laser deposition welding in industrial production. However, the technology is limited by its low deposition rates in those cases where large-surface components are to be coated while laser-typical corrosion and wear resistance characteristics are to be achieved. Examples are, e.g. hydraulic cylinders for offshore applications, tools for petroleum or gas production and mining, or large-scale conveyors. In these cases, modern laser hybrid technologies open up new applications. By effectively combining the laser energy with other energy sources, e.g. inductive heating, autogenic flames or electric resistance, high deposition rates are achieved with excellent coating qualities, which makes the laser process competitive also in the case of large-surface coatings. (orig./AKB) [German] Exzellente Praezision, hoechste mechanische Festigkeit und massgeschneiderte Eigenschaften von Oberflaechenschichten wie auch generativ erzeugten 3D-Strukturen: diese Merkmale haben dem Auftragschweissen mit Laserstrahlen zum Durchbruch in der industriellen Produktion verholfen. Die geringen Auftragraten setzen der Technologie jedoch in jenen Faellen Grenzen, wo es um Flaechenbeschichtungen grosser Bauteile geht, deren Einsatz aber dennoch die lasertypischen Schichteigenschaften hinsichtlich Korrosions- oder Verschleissbestaendigkeit erfordert. Beispiele sind lange Hydraulikzylinder im Offshore-Bereich, Werkzeuge der Oel- und Gasfoerderung und des Bergbaus sowie grosse Foerderschnecken. Hier erweitern moderne Laser-Hybridtechnologien wirkungsvoll die Einsatzmoeglichkeiten. Durch effiziente Kombination der Laserenergie mit anderen Energiequellen in Form induktiver Erwaermung, autogener Flammen oder elektrischem Widerstand werden hohe Auftragraten bei gleichzeitigem Erhalt der besonderen Schichtqualitaet erreicht, die das Laserverfahren auch bei

  1. Optimisation Of Process Parameters In High Energy Mixing As A Method Of Cohesive Powder Flowability Improvement

    Directory of Open Access Journals (Sweden)

    Leś Karolina

    2015-12-01

    Full Text Available Flowability of fine, highly cohesive calcium carbonate powder was improved using high energy mixing (dry coating method consisting in coating of CaCO3 particles with a small amount of Aerosil nanoparticles in a planetary ball mill. As measures of flowability the angle of repose and compressibility index were used. As process variables the mixing speed, mixing time, and the amount of Aerosil and amount of isopropanol were chosen. To obtain optimal values of the process variables, a Response Surface Methodology (RSM based on Central Composite Rotatable Design (CCRD was applied. To match the RSM requirements it was necessary to perform a total of 31 experimental tests needed to complete mathematical model equations. The equations that are second-order response functions representing the angle of repose and compressibility index were expressed as functions of all the process variables. Predicted values of the responses were found to be in a good agreement with experimental values. The models were presented as 3-D response surface plots from which the optimal values of the process variables could be correctly assigned. The proposed, mechanochemical method of powder treatment coupled with response surface methodology is a new, effective approach to flowability of cohesive powder improvement and powder processing optimisation.

  2. New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

    OpenAIRE

    Budding, A.; Vaneker, T.H.J.

    2013-01-01

    In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of applications, but this study solely focuses on the application for powder -based three-dimensional printing (e.g. SLS, 3DP). This research is primarily interested in powder compaction for creating membrane...

  3. Protective coatings for in-vessel fusion devices

    International Nuclear Information System (INIS)

    Brossa, F.

    1984-01-01

    Coatings of Al/Si, SAP (Sintered Aluminium Powder), Al 2 O 3 , TiC (low-Z material) and Ta have been developed for in-vessel component protection. Anodic oxidation, vapor depositions, reactive sputtering, chemical vapor deposition (CVD) and plasma spray have been the coating formation methods studied. AISI 316, 310, 304, Inconel 600 and Mo were adopted as base materials. the coatings were characterized in terms of composition, structure and connection with the supporting material. The behavior of coatings under H + , D + and He + irradiation in the energy range 100 eV-8 keV was tested and compared to the solid massive samples. TiC and Ta coatings were tested with thermal shock under power density pulses of 1 kW/cm 2 generated by an electron beam gun. Temperature-dependence of the erosion of TiC by vacuum arcs in a magnetic field was also studied. TiC coatings have low sputtering values, good resistance to arcing and a high chemical stability. TiC and Ta, CVD and plasma spray coatings are thermal-shock resistant. High thermal loads produce cracks but no spalling. Destruction occurred only after melting of the base material. The plasma spray coating method seems to be most appropriate for developing remote handling applications in fusion devices. (orig.)

  4. Wear and impact resistance of HVOF sprayedceramic matrix composites coating

    Science.gov (United States)

    Prawara, B.; Martides, E.; Priyono, B.; Ardy, H.; Rikardo, N.

    2016-02-01

    Ceramic coating has the mechanical properties of high hardness and it is well known for application on wear resistance, but on the other hand the resistance to impact load is low. Therefore its use is limited to applications that have no impact loading. The aim of this research was to obtain ceramic-metallic composite coating which has improved impact resistance compared to conventional ceramic coating. The high impact resistance of ceramic-metallic composite coating is obtained from dispersed metallic alloy phase in ceramic matrix. Ceramic Matrix Composites (CMC) powder with chrome carbide (Cr3C2) base and ceramic-metal NiAl-Al2O3 with various particle sizes as reinforced particle was deposited on mild steel substrate with High Velocity Oxygen Fuel (HVOF) thermal spray coating. Repeated impact test showed that reinforced metallic phase size influenced impact resistance of CMC coating. The ability of CMC coating to absorb impact energy has improved eight times and ten times compared with original Cr3C2 and hard chrome plating respectively. On the other hand the high temperature corrosion resistance of CMC coating showed up to 31 cycles of heating at 800°C and water quenching cooling.

  5. Plasma Sprayed Hydroxyapatite Coatings: Influence of Spraying Power on Microstructure

    International Nuclear Information System (INIS)

    Mohd, S. M.; Abd, M. Z.; Abd, A. N.

    2010-01-01

    The plasma sprayed hydroxyapatite (HA) coatings are used on metallic implants to enhance the bonding between the implant and bone in human body. The coating process was implemented at different spraying power for each spraying condition. The coatings formed from a rapid solidification of molten and partly molten particles that impact on the surface of substrate at high velocity and high temperature. The study was concentrated on different spraying power that is between 23 to 31 kW. The effect of different power on the coatings microstructure was investigated using scanning electron microscope (SEM) and phase composition was evaluated using X-ray diffraction (XRD) analysis. The coatings surface morphology showed distribution of molten, partially melted particles and some micro-cracks. The produced coatings were found to be porous as observed from the cross-sectional morphology. The coatings XRD results indicated the presence of crystalline phase of HA and each of the patterns was similar to the initial powder. Regardless of different spraying power, all the coatings were having similar XRD patterns.

  6. Corrosion performance of atmospheric plasma sprayed alumina coatings on AZ31B magnesium alloy under immersion environment

    OpenAIRE

    D. Thirumalaikumarasamy; K. Shanmugam; V. Balasubramanian

    2014-01-01

    Plasma sprayed ceramic coatings are successfully used in many industrial applications, where high wear and corrosion resistance with thermal insulation are required. The alumina powders were plasma sprayed on AZ31B magnesium alloy with three different plasma spraying parameters. In the present work, the influence of plasma spray parameters on the corrosion behavior of the coatings was investigated. The corrosion behavior of the coated samples was evaluated by immersion corrosion test in 3.5 w...

  7. Cold spray deposition of Ti{sub 2}AlC coatings for improved nuclear fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Benjamin R. [University of Wisconsin, Madison, WI (United States); Garcia-Diaz, Brenda L. [Savannah River National Laboratory, Aiken, SC (United States); Hauch, Benjamin [University of Wisconsin, Madison, WI (United States); Olson, Luke C.; Sindelar, Robert L. [Savannah River National Laboratory, Aiken, SC (United States); Sridharan, Kumar, E-mail: kumar@engr.wisc.edu [University of Wisconsin, Madison, WI (United States)

    2015-11-15

    Coatings of Ti{sub 2}AlC MAX phase compound have been successfully deposited on Zircaloy-4 (Zry-4) test flats, with the goal of enhancing the accident tolerance of LWR fuel cladding. Low temperature powder spray process, also known as cold spray, has been used to deposit coatings ∼90 μm in thickness using powder particles of <20 μm. X-ray diffraction analysis showed the phase-content of the deposited coatings to be identical to the powders indicating that no phase transformation or oxidation had occurred during the coating deposition process. The coating exhibited a high hardness of about 800 H{sub K} and pin-on-disk wear tests using abrasive ruby ball counter-surface showed the wear resistance of the coating to be significantly superior to the Zry-4 substrate. Scratch tests revealed the coatings to be well-adhered to the Zry-4 substrate. Such mechanical integrity is required for claddings from the standpoint of fretting wear resistance and resisting wear handling and insertion. Air oxidation tests at 700 °C and simulated LOCA tests at 1005 °C in steam environment showed the coatings to be significantly more oxidation resistant compared to Zry-4 suggesting that such coatings can potentially provide accident tolerance to nuclear fuel cladding. - Highlights: • Deposited Ti{sub 2}AlC coatings on Zircaloy-4 substrates with a low pressure powder spray process, also known as cold spray. • Coatings have high hardness and wear resistance for both damage resistance during rod insertion and fretting wear resistance. • The oxidation resistance of Ti{sub 2}AlC coated Zircaloy-4 at 700 °C and 1005 °C was significantly superior to uncoated Zircaloy. • Cold spray of Ti{sub 2}AlC demonstrates considerable promise as a near-term solution for accident tolerant Zr-alloy fuel claddings.

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

    OpenAIRE

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

    2016-01-01

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

  9. Influences of precursor constitution and processing speed on microstructure and wear behavior during laser clad composite coatings on γ-TiAl intermetallic alloy

    International Nuclear Information System (INIS)

    Liu Xiubo; Yu Rongli

    2009-01-01

    The effects of constitution of precursor mixed powders and scan speed on microstructure and wear properties were designed and investigated during laser clad γ/Cr 7 C 3 /TiC composite coatings on γ-TiAl intermetallic alloy substrates with NiCr-Cr 3 C 2 precursor mixed powders. The results indicate that both the constitution of the precursor mixed powders and the beam scan rate have remarkable influence on microstructure and attendant hardness as well as wear resistance of the formed composite coatings. The wear mechanisms of the original TiAl alloy and laser clad composite coatings were investigated. The composite coating with an optimum compromise between constitution of NiCr-Cr 3 C 2 precursor mixed powders as well as being processed under moderate scan speed exhibits the best wear resistance under dry sliding wear test conditions

  10. Production of metal and metal-ceramic coatings on D-Gun Ob

    International Nuclear Information System (INIS)

    Gavrilenko, T.P.; Nikolaev, Y.A.; Ulianitsky, V.Y.

    1995-01-01

    Optimization of the detonation spraying process has been made for the production of metal and metal-ceramics coatings with the D-Gun Ob. Owing to the ability of Ob to work with several fuels and an inert diluent simultaneously, variation of detonation regimes in a wide range is possible, and because of localized powder injection in the D-Gun barrel, high uniformity of parameters of powder particles is achieved. The best conditions for particle heating and acceleration were calculated with the help of mathematical simulation, and the corresponding regimes were realized on D-Gun Ob. High-quality aluminum, copper, nickel, and nickel-chromium-silicon-carbon-boron alloy coatings were produced by using only propane fuel. Chromium carbide with nickel and tungsten carbide with cobalt coatings were produced with addition of acetylene. Optimal efficiency and high bonding strength were achieved for all powders. Data on microhardness, bonding strength, and efficiency are presented

  11. Surface coating and magnetic properties of Sm2Fe17Nx materials

    International Nuclear Information System (INIS)

    Noguchi, K.; Machida, K.; Nishimura, M.; Adachi, G.

    1998-01-01

    Surface coating for finely ground Sm 2 Fe 17 N x (x=-3) powders (diameter 2 Fe 17 N x and (Zn,In)/Cu/Sm 2 Fe 17 N x , showed good oxidation-resistivity and thermal stability compared with the samples prepared without the Cu metal pre-coating, Zn/Sm 2 Fe 17 N x . The epoxy resin- or In metal-bonded magnets produced from the above coated powders, Zn/Cu/Sm 2 Fe 17 N x and (Zn,In)/Cu/Sm 2 Fe 17 N x , under warm molding conditions provided a flux loss of around -15% after standing in air at 120 C for 1000 h, but 30-40% for the conventional injection-type resin-bonded magnets prepared from Nd-Fe-B powders. (orig.)

  12. Oxidation Behavior of FeCrAl -coated Zirconium Cladding prepared by Laser Coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il-Hyun; Kim, Hyun-Gil; Choi, Byung-Kwan; Park, Jeong-Yong; Koo, Yang-Hyun; Kim, Jin-Seon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    From the recent research trends, the ATF cladding concepts for enhanced accident tolerance are divided as follows: Mo-Zr cladding to increase the high temperature strength, cladding coating to increase the high temperature oxidation resistance, FeCrAl alloy and SiC/SiCf material to increase the oxidation resistance and strength at high temperature. To commercialize the ATF cladding concepts, various factors are considered, such as safety under normal and accident conditions, economy for the fuel cycle, and developing development challenges, and schedule. From the proposed concepts, it is known that the cladding coating, FeCrAl alloy, and Zr-Mo claddings are considered as a near/mid-term application, whereas the SiC material is considered as a long-term application. Among them, the benefit of cladding coating on Zr-based alloys is the fuel cycle economy regarding the manufacturing, neutron cross section, and high tritium permeation characteristics. However, the challenge of cladding coating on Zr-based alloys is the lower oxidation resistance and mechanical strength at high-temperature than other concepts. Another important point is the adhesion property between the Zr-based alloy and coating materials. A laser coating method supplied with FeCrAl powders was developed to decrease the high-temperature oxidation rate in a steam environment through a systematic study for various coating parameters, and a FeCrAl-coated Zircaloy-4 cladding tube of 100 mm in length to the axial direction can be successfully manufactured.

  13. The adhesion strength and residual stress of colloidal-sol gel derived β-Tricalcium-Phosphate/Fluoridated-Hydroxyapatite biphasic coatings

    International Nuclear Information System (INIS)

    Cheng Kui; Zhang, Sam; Weng Wenjian; Khor, Khiam Aik; Miao Shundong; Wang Yongsheng

    2008-01-01

    β-tricalcium phosphate (β-TCP) powders are embedded in a fluoridated hydroxyapatite (FHA) matrix to form β-TCP-FHA composites via colloidal-sol gel method. This composite layer is deposited on top of a FHA layer to form a β-TCP-FHA/FHA biphasic coating. The effect of the nanosized powder on the residual stress is characterized through the X-ray diffraction peak shift. The powder incorporation increases the residual stress, while a large amount of β-TCP (Ca powder /Ca sol ratio is higher than 1/2) results in less gel shrinkage that partially compensates the mismatch of thermal expansion coefficient and thus the residual stress. Despite the elevated residual stress as more powders are embedded, the coating adhesion strength remains virtually constant: around 430 mN-500 mN in scanning scratch test

  14. TECHNOLOGICAL PECULIARITIES OF THERMAL BARRIER COATINGS BASED ON ZIRCONIUM DIOXIDE

    Directory of Open Access Journals (Sweden)

    V. V. Okovity

    2016-01-01

    does not have time to spread to a greater depth. As a result, the coating surface takes the form of solidified melt. The coating obtained from the powder of ZrO2 – 7 % Y2O3 in accordance with the developed technology can withstand heating – cooling cycles by 1.5-fold more than similar coatings being made previously. Thus the proposed method allows to increase the coating resistance to thermal cycling at temperatures of 1100 °C.

  15. In-house characterization of protein powder

    DEFF Research Database (Denmark)

    Hartmann, Christian Grundahl; Nielsen, Ole Faurskov; Ståhl, Kenny

    2010-01-01

    X-ray powder diffraction patterns of lysozyme and insulin were recorded on a standard in-house powder diffractometer. The experimental powder diffraction patterns were compared with patterns calculated from Protein Data Bank coordinate data. Good agreement was obtained by including straightforward...... to include calculated H-atom positions did not improve the overall fit and was abandoned. The method devised was shown to be a quick and convenient tool for distinguishing precipitates and polymorphs of proteins....

  16. Cryomilling of Thermoplastic Powder for Prepreg Applications

    Science.gov (United States)

    2013-09-01

    Cryomilling of Thermoplastic Powder for Prepreg Applications by Brian Parquette, Anit Giri, Daniel J. O’Brien, Sarah Brennan, Kyu Cho, and...MD 21005-5066 ARL-TR-6591 September 2013 Cryomilling of Thermoplastic Powder for Prepreg Applications Brian Parquette and Sarah Brennan...COVERED (From - To) 1 March 2012–30 May 2013 4. TITLE AND SUBTITLE Cryomilling of Thermoplastic Powder for Prepreg Applications 5a. CONTRACT

  17. Method of producing radioactive carbon powder

    International Nuclear Information System (INIS)

    Imamura, Y.

    1980-01-01

    Carbon powder, placed in a hermetically closed apparatus under vacuum together with radium ore, adsorbs radon gas emanating from the radium ore thus producing a radioactive carbonaceous material, the radioactivity of which is due to the presence of adsorbed radon. The radioactive carbon powder thus obtained has excellent therapeutical efficacy and is suitable for a variety of applications because of the mild radioactivity of radon. Radium ore permits substantially limitlessly repeated production of the radioactive carbon powder

  18. Powder handling for automated fuel processing

    International Nuclear Information System (INIS)

    Frederickson, J.R.; Eschenbaum, R.C.; Goldmann, L.H.

    1989-01-01

    Installation of the Secure Automated Fabrication (SAF) line has been completed. It is located in the Fuel Cycle Plant (FCP) at the Department of Energy's (DOE) Hanford site near Richland, Washington. The SAF line was designed to fabricate advanced reactor fuel pellets and assemble fuel pins by automated, remote operation. This paper describes powder handling equipment and techniques utilized for automated powder processing and powder conditioning systems in this line. 9 figs

  19. European coatings conference - Marine coatings. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This volume contains 13 lectures (manuscripts or powerpoint foils) with the following topics: 1. Impact of containerization on polyurethane and polyurea in marine and protective coatings (Malte Homann); 2. The application of combinatorial/high-throughput methods to the development of marine coatings (Bret Chisholm); 3. Progress and perspectives in the AMBIO (advanced nanostructured surfaces for the control of biofouling) Project (James Callow); 4. Release behaviour due to shear and pull-off of silicone coatings with a thickness gradient (James G. Kohl); 5. New liquid rheology additives for high build marine coatings (Andreas Freytag); 6. Effective corrosion protection with polyaniline, polpyrrole and polythiophene as anticorrosice additives for marine paints (Carlos Aleman); 7. Potential applications of sol gel technology for marine applications (Robert Akid); 8: Performance of biocide-free Antifouling Coatings for leisure boats (Bernd Daehne); 9. Novel biocidefree nanostructured antifouling coatings - can nano do the job? (Corne Rentrop); 10. One component high solids, VOC compliant high durability finish technology (Adrian Andrews); 11. High solid coatings - the hybrid solution (Luca Prezzi); 12. Unique organofunctional silicone resins for environmentally friendly high-performance coatings (Dieter Heldmann); 13. Silicone-alkyd paints for marine applications: from battleship-grey to green (Thomas Easton).

  20. Effect of seed treatment with milk powder and mustard flour in control of common bunt (Tilletia tritici) in wheat and stem smut (Urocystis occulta) in rye

    OpenAIRE

    Borgen, Anders; Kristensen, Lars

    2001-01-01

    In field trials mustard flour was able to control seed borne infection by common bunt (Tilletia tritici) in wheat without decreasing the germination vigour of the treated seeds. Full control of common bunt by coating the seeds with milk powder could only be achieved at doses which reduced germination vigour of the seeds. Mustard flour can be recommended as a seed treatment in organic agriculture while a treatment based on milk powder should be developed in combination with biological control....

  1. Preparation techniques for ceramic waste form powder

    International Nuclear Information System (INIS)

    Hash, M.C.; Pereira, C.; Lewis, M.A.

    1997-01-01

    The electrometallurgical treatment of spent nuclear fuels result in a chloride waste salt requiring geologic disposal. Argonne National Laboratory (ANL) is developing ceramic waste forms which can incorporate this waste. Currently, zeolite- or sodalite-glass composites are produced by hot isostatic pressing (HIP) techniques. Powder preparations include dehydration of the raw zeolite powders, hot blending of these zeolite powders and secondary additives. Various approaches are being pursued to achieve adequate mixing, and the resulting powders have been HIPed and characterized for leach resistance, phase equilibria, and physical integrity

  2. CVD carbon powders modified by ball milling

    Directory of Open Access Journals (Sweden)

    Kazmierczak Tomasz

    2015-09-01

    Full Text Available Carbon powders produced using a plasma assisted chemical vapor deposition (CVD methods are an interesting subject of research. One of the most interesting methods of synthesizing these powders is using radio frequency plasma. This method, originally used in deposition of carbon films containing different sp2/sp3 ratios, also makes possible to produce carbon structures in the form of powder. Results of research related to the mechanical modification of these powders have been presented. The powders were modified using a planetary ball mill with varying parameters, such as milling speed, time, ball/powder mass ratio and additional liquids. Changes in morphology and particle sizes were measured using scanning electron microscopy and dynamic light scattering. Phase composition was analyzed using Raman spectroscopy. The influence of individual parameters on the modification outcome was estimated using statistical method. The research proved that the size of obtained powders is mostly influenced by the milling speed and the amount of balls. Powders tend to form conglomerates sized up to hundreds of micrometers. Additionally, it is possible to obtain nanopowders with the size around 100 nm. Furthermore, application of additional liquid, i.e. water in the process reduces the graphitization of the powder, which takes place during dry milling.

  3. Effect of surface energy on powder compactibility.

    Science.gov (United States)

    Fichtner, Frauke; Mahlin, Denny; Welch, Ken; Gaisford, Simon; Alderborn, Göran

    2008-12-01

    The influence of surface energy on the compactibility of lactose particles has been investigated. Three powders were prepared by spray drying lactose solutions without or with low proportions of the surfactant polysorbate 80. Various powder and tablet characterisation procedures were applied. The surface energy of the powders was characterized by Inverse Gas Chromatography and the compressibility of the powders was described by the relationship between tablet porosity and compression pressure. The compactibility of the powders was analyzed by studying the evolution of tablet tensile strength with increasing compaction pressure and porosity. All powders were amorphous and similar in particle size, shape, and surface area. The compressibility of the powders and the microstructure of the formed tablets were equal. However, the compactibility and dispersive surface energy was dependent of the composition of the powders. The decrease in tablet strength correlated to the decrease in powder surface energy at constant tablet porosities. This supports the idea that tablet strength is controlled by formation of intermolecular forces over the areas of contact between the particles and that the strength of these bonding forces is controlled by surface energy which, in turn, can be altered by the presence of surfactants.

  4. Effect of powder geometry on densification

    International Nuclear Information System (INIS)

    Spasskij, M.R.; Spasskaya, I.A.; Shatalova, I.G.; Shchukin, E.D.

    1979-01-01

    The effect of particle shape and size composition on the processes of powder vibratory compacting is considered. Using microstress measurements in compacted structures of conglomerated and disintegrated tungsten powders as well as powder strength testing the existence of a zone of transition from a structural deformation to a plastic one has been shown. The formation of phase interparticle contacts of practically stable strength (approximately 5-6 dyn) is a characteristic feature of the zone. The width of the transition zone greatly depends upon geometrical powder properties; 55-65 % for conglomerated tungsten, 63-66 % for integrated tungsten

  5. Safety consideration when handling metal powders

    CSIR Research Space (South Africa)

    Benson, JM

    2012-03-01

    Full Text Available to some form of irritation or allergic reaction (e.g. dermatitis). In the case of nano-powders, the particles can penetrate the skin and become absorbed into cells in various parts of the body, including the brain � Eye contact, resulting in a... powders, and thus data is often limited to various ailments that have been reported for people working with that particular powder (amongs other things). There are three ways that powders can interact with the body: � Skin contact, which may lead...

  6. Study of thermal and electrical parameters of workpieces during spray coating by electrolytic plasma jet

    International Nuclear Information System (INIS)

    Khafizov, A A; Shakirov, Yu I; Valiev, R A; Valiev, R I; Khafizova, G M

    2016-01-01

    In this paper the results are presented of thermal and electrical parameters of products in the system bottom layer - intermediate layer when applying protective coatings of ferromagnetic powder by plasma spray produced in an electric discharge with a liquid cathode, on steel samples. Temperature distribution and gradients in coating and intermediate coating were examined. Detailed descriptions of spray coating with ferromagnetic powder by plasma jet obtained in electrical discharge with liquid cathode and the apparatus for obtaining thereof is provided. Problem has been solved by using of Fourier analysis. Initial data for calculations is provided. Results of numerical analysis are provided as temporal functions of temperature in contiguity between coating and intermediate coating as well as temporal function of the value Q=q-φ; where q is density of heat current directed to the free surface of intermediate coating, φ is density of heat current in contiguity between coating and intermediate coating. The analysis of data given shows that in the systems of contact heat exchange bottom layer-intermediate layer with close values of the thermophysical characteristics of constituting materials is observed a slow increase of the temperature of the contact as a function of time. (paper)

  7. Powder metallurgical high performance materials. Proceedings. Volume 4: late papers

    Energy Technology Data Exchange (ETDEWEB)

    Kneringer, G; Roedhammer, P; Wildner, H [eds.

    2001-07-01

    This is the fourth volume (late papers) of the 15th International Plansee seminar 2001 which general theme was 'Powder metallurgical high performance materials'. The seminar looked beyond the refractory metals and cemented carbides, which remain as its focus, to novel classes of materials, such as intermetallic compounds, with potential for high temperature applications. This volume 4 contains papers dealing with high performance P/M metals (ITER and fusion reactors, solid targets, materials microstructure, novel alloys, etc.), P/M hard materials ( production and characterization, tungsten carbides, titanium carbides, microstructural design, coatings composition and performance, etc.) and general topics. From 37 papers 24 correspond to INIS subject scope and they were indexed separately. (nevyjel)

  8. Powder metallurgical high performance materials. Proceedings. Volume 4: late papers

    International Nuclear Information System (INIS)

    Kneringer, G.; Roedhammer, P.; Wildner, H.

    2001-01-01

    This is the fourth volume (late papers) of the 15th International Plansee seminar 2001 which general theme was 'Powder metallurgical high performance materials'. The seminar looked beyond the refractory metals and cemented carbides, which remain as its focus, to novel classes of materials, such as intermetallic compounds, with potential for high temperature applications. This volume 4 contains papers dealing with high performance P/M metals (ITER and fusion reactors, solid targets, materials microstructure, novel alloys, etc.), P/M hard materials ( production and characterization, tungsten carbides, titanium carbides, microstructural design, coatings composition and performance, etc.) and general topics. From 37 papers 24 correspond to INIS subject scope and they were indexed separately. (nevyjel)

  9. Examples for application and diagnostics in plasma-powder interaction

    International Nuclear Information System (INIS)

    Kersten, H; Wiese, R; Thieme, G; Froehlich, M; Kopitov, A; Bojic, D; Scholze, F; Neumann, H; Quaas, M; Wulff, H; Hippler, R

    2003-01-01

    Low-pressure plasmas offer a unique possibility of confinement, control and fine tailoring of particle properties. Hence, dusty plasmas have grown into a vast field and new applications of plasma-processed dust particles are emerging. There is demand for particles with special properties and for particle-seeded composite materials. For example, the stability of luminophore particles could be improved by coating with protective Al 2 O 3 films which are deposited by a PECVD process using a metal-organic precursor gas. Alternatively, the interaction between plasma and injected micro-disperse powder particles can also be used as a diagnostic tool for the study of plasma surface processes. Two examples will be provided: the interaction of micro-sized (SiO 2 ) grains confined in a radiofrequency plasma with an external ion beam as well as the effect of a dc-magnetron discharge on confined particles during deposition have been investigated

  10. Study on Metal Microfilter Coated with Ceramics by Using Plasma Thermal Spray Method

    Energy Technology Data Exchange (ETDEWEB)

    Song, In Gyu; Shin, Hyun Myung; Choi, Hae Woon [Keimyung University, Daegu (Korea, Republic of); Lee, Young Min [Korea Polytechincs VI, Daegu (Korea, Republic of)

    2011-09-15

    This research was performed on a microfilter made of a hybrid material (ceramic + metal) that was coated with ceramics on the metal-filter surface by using the thermal spray method. The ceramic powders used were Al{sub 2}O{sub 3}+40TiO{sub 2} powder with a particle size of 20 {mu}m and Al{sub 2}O{sub 3} (98%+)powder with a particle size of 45 {mu}m. The metal filters were filter-grade 20 {mu}m, 30 {mu}m, and 50 {mu}m sintered metal powder filters (SIKA-R 20 IS, 30 IS, 50 IS: Sinter Metals Filters) and filter-grade 75 {mu}m sintered mesh filter with five layers. Ceramic-coated filters that were coated using the thermal spray method had a great influence on powder material, particle size, and coating thickness. However, these filters showed a fine performance when used as micro-filters.

  11. Enhanced ductility in thermally sprayed titania coating synthesized using a nanostructured feedstock

    International Nuclear Information System (INIS)

    Lima, R.S.; Marple, B.R.

    2005-01-01

    Nanostructured and conventional titania (TiO 2 ) feedstock powders were thermally sprayed via high velocity oxy-fuel (HVOF). The microstructure, porosity, Vickers hardness, crack propagation resistance, bond strength (ASTM C633), abrasion behavior (ASTM G65) and the wear scar characteristics of these two types of coatings were analyzed and compared. The coating made from the nanostructured feedstock exhibited a bimodal microstructure, with regions containing particles that were fully molten (conventional matrix) and regions with embedded particles that were semi-molten (nanostructured zones) during the thermal spraying process. The bimodal coating also exhibited higher bond strength and higher wear resistance when compared to the conventional coating. By comparing the wear scars of both coatings (via scanning electron microscopy and roughness measurements) it was observed that when the coatings were subjected to the same abrasive conditions the wear scar of the bimodal coating was smoother, with more plastically deformed regions than the conventional coating. It was concluded that this enhanced ductility of the bimodal coating was caused by its higher toughness. The results suggest that nanostructured zones randomly distributed in the microstructure of the bimodal coating act as crack arresters, thereby enhancing toughness and promoting higher critical depth of cut, which provides a broader plastic deformation range than that exhibited by the conventional coating. This work provides evidence that the enhanced ductility of the bimodal coating is a nanostructured-related property, not caused by any other microstructural artifact

  12. Dry coating of solid dosage forms: an overview of processes and applications.

    Science.gov (United States)

    Foppoli, Anastasia Anna; Maroni, Alessandra; Cerea, Matteo; Zema, Lucia; Gazzaniga, Andrea

    2017-12-01

    Dry coating techniques enable manufacturing of coated solid dosage forms with no, or very limited, use of solvents. As a result, major drawbacks associated with both organic solvents and aqueous coating systems can be overcome, such as toxicological, environmental, and safety-related issues on the one hand as well as costly drying phases and impaired product stability on the other. The considerable advantages related to solventless coating has been prompting a strong research interest in this field of pharmaceutics. In the article, processes and applications relevant to techniques intended for dry coating are analyzed and reviewed. Based on the physical state of the coat-forming agents, liquid- and solid-based techniques are distinguished. The former include hot-melt coating and coating by photocuring, while the latter encompass press coating and powder coating. Moreover, solventless techniques, such as injection molding and three-dimensional printing by fused deposition modeling, which are not purposely conceived for coating, are also discussed in that they would open new perspectives in the manufacturing of coated-like dosage forms.

  13. 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

  14. 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.

  15. Coatings for laser fusion

    International Nuclear Information System (INIS)

    Lowdermilk, W.H.

    1981-01-01

    Optical coatings are used in lasers systems for fusion research to control beam propagation and reduce surface reflection losses. The performance of coatings is important in the design, reliability, energy output, and cost of the laser systems. Significant developments in coating technology are required for future lasers for fusion research and eventual power reactors

  16. Fuel particle coating data

    International Nuclear Information System (INIS)

    Hollabaugh, C.M.; Wagner, P.; Wahman, L.A.; White, R.W.

    1977-01-01

    Development of coating on nuclear fuel particles for the High-Temperature Fuels Technology program at the Los Alamos Scientific Laboratory included process studies for low-density porous and high-density isotropic carbon coats, and for ZrC and ''alloy'' C/ZrC coats. This report documents the data generated by these studies

  17. Protection of uranium by metallic coatings

    International Nuclear Information System (INIS)

    Baque, P.; Koch, P.; Dominget, R.; Darras, R.

    1968-01-01

    A study is made of the possibilities of inhibiting or limiting, by means of protective metallic coatings, the oxidation of uranium by carbon dioxide at high temperature. In general, surface films containing intermetallic compounds or solid solutions of uranium with aluminium, zirconium, copper, niobium, nickel or chromium are formed, according to the techniques employed which are described here. The processes most to be recommended are those of direct diffusion starting from a thin sheet or tube, of vacuum deposition, or of immersion in a molten bath of suitable composition. The conditions for preparing these coatings have been optimized as a function of the protective effect obtained in carbon dioxide at 450 or at 500 C. Only the aluminium and zirconium based coatings are really satisfactory since they can lead to a reduction by a factor of 5 to 10 in the oxidation rate of uranium in the conditions considered; they make it possible in particular to avoid or to reduce to a very large extent the liberation of powdered oxide. Furthermore, the coatings produced generally give the uranium good protection against atmospheric corrosion. (author) [fr

  18. Modified corrosion protection coatings for Concrete tower of Transmission line

    Science.gov (United States)

    Guo, Kai; Jing, Xiangyang; Wang, Hongli; Yue, Zengwu; Wu, Yaping; Mi, Xuchun; Li, Xingeng; Chen, Suhong; Fan, Zhibin

    2017-12-01

    By adding nano SiO2 particles, an enhanced K-PRTV anti-pollution flashover coating had been prepared. Optical profile meter (GT-K), atomic force microscopy (AFM) and infrared spectrometer (FT-IR) characterization were carried out on the coating surface analysis. With the use of modified epoxy resin as the base material, the supplemented by phosphate as a corrosion stabilizer, to achieve a corrosion of steel and galvanized steel with rust coating. Paint with excellent adhesion, more than 10MPa (1), resistant to neutral salt spray 1000h does not appear rust point. At the same time coating a large amount of ultra-fine zinc powder can be added for the tower galvanized layer zinc repair function, while the paint in the zinc powder for the tower to provide sacrificial anode protection, to achieve self-repair function of the coating. Compared to the market with a significant reduction in the cost of rust paint, enhance the anti-corrosion properties.

  19. Numerical Analysis of the Effect of Particle Shape and Adhesion on the Segregation of Powder Mixtures

    Directory of Open Access Journals (Sweden)

    Alizadeh Behjani Mohammadreza

    2017-01-01

    Full Text Available Segregation of granules is an undesired phenomenon in which particles in a mixture separate from each other based on the differences in their physical and chemical properties. It is, therefore, crucial to control the homogeneity of the system by applying appropriate techniques. This requires a fundamental understanding of the underlying mechanisms. In this study, the effect of particle shape and cohesion has been analysed. As a model system prone to segregation, a ternary mixture of particles representing the common ingredients of home washing powders, namely, spray dried detergent powders, tetraacetylethylenediamine, and enzyme placebo (as the minor ingredient during heap formation is modelled numerically by the Discrete Element Method (DEM with an aim to investigate the effect of cohesion/adhesion of the minor components on segregation quality. Non-spherical particle shapes are created in DEM using the clumped-sphere method based on their X-ray tomograms. Experimentally, inter particle adhesion is generated by coating the minor ingredient (enzyme placebo with Polyethylene Glycol 400 (PEG 400. The JKR theory is used to model the cohesion/adhesion of coated enzyme placebo particles in the simulation. Tests are carried out experimentally and simulated numerically by mixing the placebo particles (uncoated and coated with the other ingredients and pouring them in a test box. The simulation and experimental results are compared qualitatively and quantitatively. It is found that coating the minor ingredient in the mixture reduces segregation significantly while the change in flowability of the system is negligible.

  20. INVESTIGATION OF THE PROPERTIES OF THE SUSPENSIONS FOR NON-STICK COATINGS FOR FOUNDRY

    Directory of Open Access Journals (Sweden)

    T. Gil’manshina

    2015-01-01

    Full Text Available The research aimed at figuring out dependence of the technological properties (density, thickness of the coating, reduced strength and sedimentation stability of the suspensions for nonstick coatings on the for activation time powder quartz graphite filler. It is shown that with increasing activation time to 10 minutes all the basic properties of graphite suspension powder quartz were improved. The paper presents the results of comparative studies of technological properties of suspensions of activated graphite oxide compositions prepared on the basis of activated aluminum oxide and periclase. The resulting suspension may be recommended for cast iron and non-ferrous castings.