WorldWideScience

Sample records for metal coating

  1. Metallic coating of microspheres

    International Nuclear Information System (INIS)

    Meyer, S.F.

    1980-01-01

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

  2. Metallic coating of microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, S.F.

    1980-08-15

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates.

  3. LEVELING METAL COATINGS

    Science.gov (United States)

    Gage, H.A.

    1959-02-10

    A method is described for applying metallic coatings to a cylinder of uranium. An aluminum-silicon coat is applied by a process consisting of first cleaning the article by immersion for 5 minutes in 50% nitric acid at 65 C. The article then is dipped through a flux, prepared by adding 10% sodium fluoride to 90% of a flux comprising 53% potassium chloride, 42% lithium chloride, and 5% sodium chloride at 560 for 2 minutes and then directly into a molten metal bath comprising 99% aluminun and 12% silicon at 620 C for 3 minutes. While the coating is yet molten the article is transferred to a pair of steel rollers and rolled until the coating solidifies. By varying the composition of the flux other metals such as zinc, lead or the like may be coated on uranium in a similar manner.

  4. Corrosion protective coating for metallic materials

    Science.gov (United States)

    Buchheit, R.G.; Martinez, M.A.

    1998-05-26

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

  5. ANTIREFLECTION MULTILAYER COATINGS WITH THIN METAL LAYERS

    Directory of Open Access Journals (Sweden)

    L. A. Gubanova

    2016-03-01

    Full Text Available The design of anti-reflective coatings for metal surfaces of Al, Ti, N,i Cr is proposed. The coatings have the form of alternating layers of dielectric/metal/dielectric with the number of cells up to15. The method of calculation of such coatings is proposed. We have calculated the coatings of the type [HfO2/Cr/HfO2]15, [ZrO2/Ti/Al2O3]15, [ZrO2/Cr/ZrO2]15. It is shown that the proposed interference coatings provide reduction of the residual reflectance of the metal several times (from 3.5 to 6.0 in a wide spectral range (300-1000 nm. The proposed coatings can be recommended as anti-reflective coatings for energy saving solar systems and batteries, and photovoltaic cells.

  6. Experimental evaluation of coating delamination in vinyl coated metal forming

    International Nuclear Information System (INIS)

    Son, Young Ki; Lee, Chan Joo; Kim, Byung Min; Lee, Jung Min; Byoen, Sang Doek; Lee, Soen Bong

    2012-01-01

    In this paper, a new evaluation and prediction method for coating delamination during sheet metal forming is presented. On the basis of the forming limit diagram (FLD), the current study evaluates the delamination of PET coating by using a cross cut specimen, dome test, and rectangular cup drawing test. Dome test specimens were subjected to biaxial, plane strain, and uniaxial deformation modes. Rectangular cup drawing test specimens were subjected to the deep drawing deformation mode, and compression deformation mode. A vinyl coated metal (VCM) sheet consists of three layers of polymer on the sheet metals: a protective film, a PET layer and a PVC layer. The areas with coating delamination were identified, and the results of the evaluation were plotted according to major and minor strain values, depicting coating delamination. The constructed delamination limit diagram (DLD) can be used to determine the forming limit of VCM during the complex press forming process. ARGUS (GOM) was employed to identify the strain value and deformation mode of the delaminated surface after the press forming. After identifying the areas of delamination, the DLD of the PET coating can be constructed in a format similar to that of the FLD. The forming limit of the VCM sheet can be evaluated using the superimposition of the delamination limit strain of the coating onto the FLD of VCM sheet. The experimental results showed that the proposed test method will support the sheet metal forming process design for VCM sheets. The assessment method presented in this study can be used to determine the delamination limit strain under plastic deformation of other polymer coated metals. The experimental results suggested that the proposed testing method is effective in evaluating delamination for specific applications

  7. Coatings for osseointegration of metallic biomaterials

    NARCIS (Netherlands)

    Wang, D.; Wu, G.; Lin, X.; Liu, Y.; Wen, C.

    2015-01-01

    This chapter discusses the application of coatings for improving the osseointegration of metallic implant materials. First, the definition of osseointegration and the methods for evaluating the osseointegration are described. The chapter then reviews the biological process of osseointegration.

  8. Barrier Coatings for Refractory Metals and Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-02-23

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

  9. Barrier Coatings for Refractory Metals and Superalloys

    International Nuclear Information System (INIS)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-01-01

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life

  10. Dry Sintered Metal Coating of Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    James C. Nicholson

    2016-09-01

    Full Text Available Halloysite nanotubes (HNTs are a naturally-occurring aluminosilicate whose dimensions measure microns in length and tens of nanometers in diameter. Bonding defects between the alumina and silica lead to net negative and positive charges on the exterior and interior lumen, respectively. HNTs have been shown to enhance the material properties of polymer matrices and enable the sustained release of loaded chemicals, drugs, and growth factors. Due to the net charges, these nanotubes can also be readily coated in layered-depositions using the HNT exterior lumen’s net negative charge as the basis for assembly. These coatings are primarily done through wet chemical processes, the majority of which are limited in their use of desired chemicals, due to the polarity of the halloysite. Furthermore, this restriction in the type of chemicals used often requires the use of more toxic chemicals in place of greener options, and typically necessitates the use of a significantly longer chemical process to achieve the desired coating. In this study, we show that HNTs can be coated with metal acetylacetonates—compounds primarily employed in the synthesis of nanoparticles, as metal catalysts, and as NMR shift reagents—through a dry sintering process. This method was capable of thermally decaying the metal acetylacetonate, resulting in a free positively-charged metal ion that readily bonded to the negatively-charged HNT exterior, resulting in metallic coatings forming on the HNT surface. Our coating method may enable greater deposition of coated material onto these nanotubes as required for a desired application. Furthermore, the use of chemical processes using toxic chemicals is not required, thus eliminating exposure to toxic chemicals and costs associated with the disposal of the resultant chemical waste.

  11. Bioactive calcium phosphate coatings on metallic implants

    Science.gov (United States)

    Sedelnikova, M. B.; Komarova, E. G.; Sharkeev, Yu. P.; Tolkacheva, T. V.; Khlusov, I. A.; Sheikin, V. V.

    2017-09-01

    Biocomposites based on bioinert metals or alloys and bioactive calcium phosphate coatings are a promising tendency of the new-generation implants development. In recent years, the approach of regenerative medicine based on the use of biodegradable biomaterials has been priority direction. Such materials are capable of initiating the bone tissue regeneration and replaced by the newly formed bone. The microarc oxidation (MAO) method allows obtaining the bioactive coatings with a porous structure, special functional properties, and modified by the essential elements. During the last decade, the investigations in the field of the nanostructured biocomposites based on bioinert Ti, Zr, Nb and their alloys with a calcium phosphate coatings deposited by the MAO method have been studied in the Institute of Strength Physics and Materials Science SB RAS, Tomsk. In this article the possibility to produce the bioactive coatings with high antibacterial and osseoconductive properties due to the introduction in the coatings of Zn, Cu, Ag, La, Si elements and wollastonite CaSiO3 was shown. The high hydrophilic and bioresorbed coatings stimulate the processes of osseointegration of the implant into the bone tissue. A promising direction in the field of the medical material science is a development of the metallic implants with good biomechanical compatibility to the bone, such as Ti-Nb alloys with a low elastic modulus that can be classified as biomaterials of the second generation. Zr and its alloys are promising materials for the dentistry and orthopedic surgery due to their high strength and corrosion resistance. Biodegradable Mg alloys are biomaterials of third generation. Such materials can dissolve with a certain speed in human body and excreted from the body thereby excluding the need for reoperation. This article presents the analysis of the study results of bioactive MAO coatings on Ti, Ti-Nb, Zr-Nb and Mg alloys and their promising medical application.

  12. Bioactive glass coatings for orthopedic metallic implants

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Esteban, Sonia; Saiz, Eduardo; Fujino, Sigheru; Oku, Takeo; Suganuma, Katsuaki; Tomsia, Antoni P.

    2003-06-30

    The objective of this work is to develop bioactive glass coatings for metallic orthopedic implants. A new family of glasses in the SiO2-Na2O-K2O-CaO-MgO-P2O5 system has been synthesized and characterized. The glass properties (thermal expansion, softening and transformation temperatures, density and hardness) are in line with the predictions of established empirical models. The optimized firing conditions to fabricate coatings on Ti-based and Co-Cr alloys have been determined and related to the glass properties and the interfacial reactions. Excellent adhesion to alloys has been achieved through the formation of 100-200 nm thick interfacial layers (Ti5Si3 on Ti-based alloys and CrOx on Co-Cr). Finally, glass coatings, approximately 100 mu m thick, have been fabricated onto commercial Ti alloy-based dental implants.

  13. Instrumental color control for metallic coatings

    Science.gov (United States)

    Chou, W.; Han, Bing; Cui, Guihua; Rigg, Bryan; Luo, Ming R.

    2002-06-01

    This paper describes work investigating a suitable color quality control method for metallic coatings. A set of psychological experiments was carried out based upon 50 pairs of samples. The results were used to test the performance of various color difference formulae. Different techniques were developed by optimising the weights and/or the lightness parametric factors of colour differences calculated from the four measuring angles. The results show that the new techniques give a significant improvement compared to conventional techniques.

  14. A Study of Deposition Coatings Formed by Electroformed Metallic Materials

    OpenAIRE

    Hayashi, Shoji; Sugiyama, Shuta; Shimura, Kojiro; Tobayama, Go; Togashi, Toshio

    2016-01-01

    Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface ...

  15. A Study of Deposition Coatings Formed by Electroformed Metallic Materials.

    Directory of Open Access Journals (Sweden)

    Shoji Hayashi

    Full Text Available Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface treatment is clinically evaluated by peeling and flex tests. However, these testing methods are not ideal for deposition coating strength measurement of electroformed metals. There have been no studies on the deposition coating strength and methods to test electroformed metals. We developed a new deposition coating strength test for electroformed metals. The influence of the negative electrolytic method, which is one of the electrochemical surface treatments, on the strength of the deposition coating of electroformed metals was investigated, and the following conclusions were drawn: 1. This process makes it possible to remove residual deposits on the electrodeposited metal surface layer. 2. Cathode electrolysis is a simple and safe method that is capable of improving the surface treatment by adjustments to the current supply method and current intensity. 3. Electrochemical treatment can improve the deposition coating strength compared to the physical or chemical treatment methods. 4. Electro-deposition coating is an innovative technique for the deposition coating of electroformed metal.

  16. 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

  17. Enhanced extinction of electromagnetic radiation by metal-coated fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Moshe [Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100 (Israel)]. E-mail: moshe@iibr.gov.il; Gurwich, Ioseph [Life Science Research Israel, Ltd., P.O. Box 139, Ness-Ziona 70451 (Israel); Shiloah, Nir [Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100 (Israel)

    2007-07-15

    The scattering properties of metal-coated fibers are studied. It is shown that an optimal thickness of the metal layer exists, for which the extinction efficiency can significantly exceed the extinction efficiency of uncoated homogeneous metal fibers of identical size. At the same time the scattering efficiency of coated fibers remains lower than that of the homogeneous ones.

  18. Superconductivity in metal-coated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Calandra, Matteo; Mauri, Francesco [IMPMC, Universite Paris 6, CNRS, 4 Place Jussieu, 75005 Paris (France); Profeta, Gianni [SPIN-CNR - Dipartimento di Fisica Universita degli Studi di L' Aquila, 67100 L' Aquila (Italy)

    2012-12-15

    In this work we explore, by first-principles density functional theory (DFT) calculations, the possibility of inducing electron-phonon mediated superconductivity in a graphene sheet by doping its surface with alkaline metal adatoms. We demonstrate that, contrary to what could be naively believed, simple exfoliation to one layer of superconducting graphite intercalated compounds (GICs) does not necessarily lead to superconducting graphene, as it is the case in CaC{sub 6}. On the contrary, it is meaningful to look for superconductivity in monolayers obtained by exfoliating non-superconducting GICs. In particular, we demonstrate that Li coating and double-coating of graphene leads to superconductivity in graphene with T{sub c} that could be as large as 18 K. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Failure Mechanisms of the Coating/Metal Interface in Waterborne Coatings: The Effect of Bonding

    Science.gov (United States)

    Wan, Hongxia; Song, Dongdong; Li, Xiaogang; Zhang, Dawei; Gao, Jin; Du, Cuiwei

    2017-01-01

    Waterborne coating is the most popular type of coating, and improving its performance is a key point of research. Cathodic delamination is one of the major modes of failure for organic coatings. It refers to the weakening or loss of adhesion between the coating and substrate. Physical and chemical characteristics of coatings have been studied via scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurements, Fourier transform infrared spectroscopy (FTIR), and secondary ion mass spectrometry (SIMS). Early heterogeneous swelling at the metal-coating interface in non-defective coated metals was elucidated using frequency-dependent alternating-current scanning electrochemical microscopy. Two types of coatings (styrene-acrylic coating and terpolymer coating) were compared. The effects of thickness, surface roughness, and chemical bonding on cathodic delamination were investigated. PMID:28772757

  20. Failure Mechanisms of the Coating/Metal Interface in Waterborne Coatings: The Effect of Bonding

    Directory of Open Access Journals (Sweden)

    Hongxia Wan

    2017-04-01

    Full Text Available Waterborne coating is the most popular type of coating, and improving its performance is a key point of research. Cathodic delamination is one of the major modes of failure for organic coatings. It refers to the weakening or loss of adhesion between the coating and substrate. Physical and chemical characteristics of coatings have been studied via scanning electron microscopy (SEM, atomic force microscopy (AFM, contact angle measurements, Fourier transform infrared spectroscopy (FTIR, and secondary ion mass spectrometry (SIMS. Early heterogeneous swelling at the metal-coating interface in non-defective coated metals was elucidated using frequency-dependent alternating-current scanning electrochemical microscopy. Two types of coatings (styrene-acrylic coating and terpolymer coating were compared. The effects of thickness, surface roughness, and chemical bonding on cathodic delamination were investigated.

  1. Metal nanoparticle doped coloured coatings on glasses and plastics ...

    Indian Academy of Sciences (India)

    Wintec

    Metal (single/mixed/alloy) nanoparticles; surface plasmon; coloured coatings on glasses and plas- tics; layer-by-layer coatings by sol–gel ... the particle size and shape, concentration, refractive index of the surrounding medium .... coatings were also prepared for the measurement of matrix refractive index values. The details ...

  2. Investigation of metal coatings for the free electron laser

    International Nuclear Information System (INIS)

    Scott, M.L.; Arendt, P.N.; Springer, R.W.; Cordi, R.C.; McCreary, W.J.

    1985-01-01

    We are investigating the deposition and characteristics of metal coatings for use in environments such as the Free Electron Laser where the radiation resistance of metal coatings could prove to be of great benefit. We have concentrated our initial efforts on silver laminate coatings due to the high reflectance of silver at 1 micron wavelength. Our initial laminate coatings have utilized thin layers of titanium oxide to break up the columnar structure of the silver during electron-beam deposition on fused silica substrates. Our initial results on equal coating thickness samples indicate an improvement in damage threshold that ranges from 1.07 to 1.71 at 351 nm

  3. Metallic component with a chromium carbide base protective coating

    International Nuclear Information System (INIS)

    Wolfla, T.A.; Tucker, R.C. Jr.

    1976-01-01

    The invention concerns a coating system to protect metal components in sodium and helium cooled nuclear reactors. It includes a nickel or iron based alloy metal substrate, a first coat formed on the substrate and comprising chromium carbides and a binder selected among the chromium-nickel, chromium-cobalt, chromium-iron alloys and the super-alloys, the first coating being between 25 and 380 microns thick, and a surface coating comprising pure chromium carbides and being between 12.5 and 125 microns thick [fr

  4. 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

  5. Development of metal based thermal barrier coatings

    Science.gov (United States)

    Shin, Dong-Il

    In this work, metal-based thermal barrier coatings (MBTBCs) have been produced, using high frequency induction plasma spraying (IPS) of iron-based nanostructured alloy powders. Important advances have been made over recent years to the development of ceramic-based thermal barrier coatings (TBCs) for internal combustion engines application, but they are not yet applied in mass production situations. Besides the important economic considerations, the reliability of ceramic: TBCs is also an issue, being associated with the difficulty of predicting their "in-service" lifetime. Through engineering of the nano/amorphous structure of MBTBCs, their thermal conductivity can be made as low as those of ceramic-based TBCs, with reduced mean free paths of the electrons/phonons scattering. In this work, nano/amorphous structured coatings were deposited by IPS using the following spray parameters: spraying distance (210 ˜ 270 mm), plasma gas composition (Ar/N2), IPS torch power (24kW), and powder feed-rate (16g/min.). The structure and properties of the deposited layers were characterized through SEM (Scanning Electron Microscopy) observations. The thermal diffusivity (alpha) properties of the MBTBCs were measured using a laser flash method. Density (rho) and specific heat (Cp) of the MBTBCs were also measured, and their thermal conductivity (k) calculated (k =alpharhoCp). The thermal conductivity of MBTBCs was found to be as low as 1.99 W/m/K. The heat treatment study showed that crystal structure changes, and grain size growth from a few nanometers to tenth of nanometers occurred at 550°C under static exposure conditions. Thermal expansion coefficient (TEC) of MBTBCs was 13E-6/K, which is close to the TEC of cast iron and thus, closer to the TEC values of aluminium alloys than are conventional TBCs. Fracture toughness of MBTBCs has also been assessed by use of Vickers hardness tests, with a 500 g load for 15 s, and the results show that there are no measurable crack

  6. Dielectric relaxation in metal-coated particles: the dramatic role of nano-scale coatings

    International Nuclear Information System (INIS)

    Youngs, I J; Bowler, N; Lymer, K P; Hussain, S

    2005-01-01

    Insulating materials filled with conducting particles permit tailoring of electrical, electromagnetic and thermal properties of the resulting composite. When the filler particles are small and metallic, a dielectric relaxation due to interfacial polarization is commonly observed at optical or smaller wavelengths. Here, experimental results are presented in which the dielectric relaxation is shifted to microwave frequencies as a result of using metal-coated dielectric particles with a nano-scale coating thickness. The results are analysed in the context of effective medium theory adapted for multi-layer particles. Such a large shift in relaxation frequency, compared with that for a similar composite with solid metal filler particles, is shown to be a function of both the coating geometry and a thin-film-related reduction in the conductivity of the metal. The observed broadening of the relaxation peak is attributed to non-uniformity of the coating thickness and a consequent distribution of coating conductivity

  7. Ionic Transport Through Metal-Rich Organic Coatings

    Science.gov (United States)

    2016-08-19

    1 (2009): pp 1012-1013. 9. X. Zhang, F.Wang, Y. Du, “Effect of Nano-Sized Titanium Powder Addition on Corrosion Performance of Epoxy Coatings...choosing a coating is the substrate in question, the desired end use for the final product , and the environment in which the final product will be... product . Herein, we discuss the performance of one type of organic coatingmetal-rich organic primer – as an ionic and electronic barrier for

  8. Performance of Bond Coats Modified by Platinum Group Metals for Applications in Thermal Barrier Coatings

    Science.gov (United States)

    Tawancy, H. M.; Alhems, Luai M.; Aboelfotoh, M. O.

    2017-07-01

    We have investigated the partial replacement of Pt with other less expensive Pt group metals on the properties of γ' + γ bond coats used in thermal barrier coatings (TBCs) deposited on a nickel-base superalloy. The microstructure, thermal stability, oxidation behavior and performance in TBC systems of bond coats synthesized with Pt + Ru, Pt + Ir and Pt + Rh are compared with those of a reference bond coat synthesized with Pt. Yttria-stabilized zirconia has been employed as top coat in all coating systems. It is shown that at high temperatures all bond coats are degraded by interdiffusion and oxidation, however, with different kinetics. The lifetime of each TBC system is found to be limited by the cohesion between the thermally grown oxide and underlying bond coat. Differences in the behavior of various bond coats are correlated with their properties. Among the three Pt group metals investigated, the properties of the Pt + Ru bond coat are shown to closely approach those of the Pt bond coat. It is concluded that Ru with much lower cost presents a potential candidate for reducing the consumption of Pt.

  9. Diagnostics of transparent polymer coatings of metal items

    Science.gov (United States)

    Varepo, L. G.; Ermakova, I. N.; Nagornova, I. V.; Kondratov, A. P.

    2017-08-01

    The methods of visual and instrumental express diagnostics of safety critical defects and non-uniform thickness of transparent mono- and multilayer polyolefin surface coating of metal items are analyzed in the paper. The instrumental diagnostics method relates to colorimetric measuring based on effects, which appear in the polarized light for extrusion polymer coatings. A color coordinates dependence (in the color system CIE La*b*) on both HDPE / PVC coating thickness fluctuation values (from average ones) and coating interlayer or adhesion layer delaminating is shown. A variation of color characteristics in the polarized light at a liquid penetration into delaminated polymer layers is found. Measuring parameters and critical uncertainties are defined.

  10. Testing internal coatings in metal vessels

    Science.gov (United States)

    Ruby, A.; Perkins, P.

    1978-01-01

    Presence of pinholes or defects in nonconductive protective coating on inside surface of closed vessel is detected if vessel has one opening into which small stainless-steel probe can be introduced. By inserting probe and attaching another to outside surface, and by filling vessel with ten percent sodium chloride solution, integrity of coating is determined by measuring electrical conductivity through vessel wall.

  11. Coatings Preserve Metal, Stone, Tile, and Concrete

    Science.gov (United States)

    2014-01-01

    John B. Schutt, a chemist at Goddard Space Flight Center, created a coating for spacecraft that could resist corrosion and withstand high heat. After retiring from NASA, Schutt used his expertise to create new formulations for Daytona Beach, Florida-based Adsil Corporation, which now manufactures a family of coatings to preserve various surfaces. Adsil has created 150 jobs due to the products.

  12. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Science.gov (United States)

    2010-04-01

    ... porous-coated uncemented prosthesis. 888.3358 Section 888.3358 Food and Drugs FOOD AND DRUG... Devices § 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis. (a) Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a device...

  13. Novel Thiol-Ene Hybrid Coating for Metal Protection

    Directory of Open Access Journals (Sweden)

    Mona Taghavikish

    2016-04-01

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

  14. Magnetic metal nanoparticles coated polyacrylonitrile textiles as microwave absorber

    Science.gov (United States)

    Akman, O.; Kavas, H.; Baykal, A.; Toprak, M. S.; Çoruh, Ali; Aktaş, B.

    2013-02-01

    Polyacrylonitrile (PAN) textiles with 2 mm thickness are coated with magnetic nanoparticles in coating baths with Ni, Co and their alloys via an electroless metal deposition method. The crystal structure, morphology and magnetic nature of composites are investigated by X-ray Powder diffraction, Scanning Electron Microscopy, and dc magnetization measurement techniques. The frequency dependent microwave absorption measurements have been carried out in the frequency range of 12.4-18 GHz (X and P bands). Diamagnetic and ferromagnetic properties are also investigated. Finally, the microwave absorption of composites is found strongly dependent on the coating time. One absorption peak is observed between 14.3 and 15.8 GHz with an efficient absorption bandwidth of 3.3-4.1 GHz (under -20 dB reflection loss limit). The Reflection loss (RL) can be achieved between -30 and -50 dB. It was found that the RL is decreasing and absorption bandwidth is decreasing with increasing coating time. While absorption peak moves to lower frequencies in Ni coated PAN textile, it goes higher frequencies in Co coated ones. The Ni-Co alloy coated composites have fluctuating curve of absorption frequency with respect to coating time. These results encourage further development of magnetic nanoparticle coated textile absorbers for broadband applications.

  15. Surface coating for prevention of metallic seed migration in tissues

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyunseok; Park, Jong In [Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Won Seok; Park, Min [Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul 151-742 (Korea, Republic of); Son, Kwang-Jae [Hanaro Applications Research, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Bang, Young-bong [Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Choy, Young Bin, E-mail: ybchoy@snu.ac.kr, E-mail: sye@snu.ac.kr [Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul 110-744 (Korea, Republic of); Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University, Seoul 110-744 (Korea, Republic of); Ye, Sung-Joon, E-mail: ybchoy@snu.ac.kr, E-mail: sye@snu.ac.kr [Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270 (Korea, Republic of); Department of Radiation Oncology, Seoul National University Hospital, Seoul 110-744 (Korea, Republic of)

    2015-06-15

    Purpose: In radiotherapy, metallic implants often detach from their deposited sites and migrate to other locations. This undesirable migration could cause inadequate dose coverage for permanent brachytherapy and difficulties in image-guided radiation delivery for patients. To prevent migration of implanted seeds, the authors propose a potential strategy to use a biocompatible and tissue-adhesive material called polydopamine. Methods: In this study, nonradioactive dummy seeds that have the same geometry and composition as commercial I-125 seeds were coated in polydopamine. Using scanning electron microscopy and x-ray photoelectron spectroscopy, the surface of the polydopamine-coated and noncoated seeds was characterized. The detachment stress between the two types of seeds and the tissue was measured. The efficacy of polydopamine-coated seed was investigated through in vitro migration tests by tracing the seed location after tissue implantation and shaking for given times. The cytotoxicity of the polydopamine coating was also evaluated. Results: The results of the coating characterization have shown that polydopamine was successfully coated on the surface of the seeds. In the adhesion test, the polydopamine-coated seeds had 2.1-fold greater detachment stress than noncoated seeds. From the in vitro test, it was determined that the polydopamine-coated seed migrated shorter distances than the noncoated seed. This difference was increased with a greater length of time after implantation. Conclusions: The authors suggest that polydopamine coating is an effective technique to prevent migration of implanted seeds, especially for permanent prostate brachytherapy.

  16. Metallic and nonmetallic coatings for ICF targets

    International Nuclear Information System (INIS)

    Hendricks, C.D.; Crane, J.K.; Hsieh, E.J.; Meyer, S.F.

    1981-01-01

    Some fusion targets designed to be driven by 0.35 to 1 μm laser light are glass spheres coated with layers of various materials such as hydrocarbons, fluorocarbons, beryllium, copper, gold, platinum, etc. The glass shell, which is filled with gas, liquid or solid deuterium-tritium fuel, must have remarkably good surface and wall thickness uniformity. Methods for depositing the various materials will be discussed. They include plasma polymerization, electro-deposition, sputtering and evaporation. Many of the difficulties encountered in the coating processes are the result of coating on free spheres with very small radii - 35 to 500 micrometers. Several means of overcoming the problems will be described and experimental results presented

  17. Metal-Coated Optical Fibers for High Temperature Applications

    Science.gov (United States)

    Zeakes, Jason; Murphy, Kent; Claus, Richard; Greene, Jonathan; Tran, Tuan

    1996-01-01

    A DC magnetron sputtering system has been used to actively coat optical fibers with hermetic metal coatings during the fiber draw process. Thin films of Inconel 625 have been deposited on optical fibers and annealed in air at 2000 F. Scanning electron microscopy and Auger electron microscopy have been used to investigate the morphology and composition of the films prior to and following thermal cycling. Issues to be addressed include film adhesion, other coating materials, and a discussion of additional applications for this novel technology.

  18. An Optically Driven Bistable Janus Rotor with Patterned Metal Coatings.

    Science.gov (United States)

    Zong, Yiwu; Liu, Jing; Liu, Rui; Guo, Honglian; Yang, Mingcheng; Li, Zhiyuan; Chen, Ke

    2015-11-24

    Bistable rotation is realized for a gold-coated Janus colloidal particle in an infrared optical trap. The metal coating on the Janus particles are patterned by sputtering gold on a monolayer of closely packed polystyrene particles. The Janus particle is observed to stably rotate in an optical trap. Both the direction and the rate of rotation can be experimentally controlled. Numerical calculations reveal that the bistable rotation is the result of spontaneous symmetry breaking induced by the uneven curvature of the coating patterns on the Janus sphere. Our results thus provide a simple method to construct large quantities of fully functional rotary motors for nano- or microdevices.

  19. Protective coatings for metal alloys and methods incorporating the same

    Science.gov (United States)

    Seabaugh, Matthew M.; Ibanez, Sergio; Swartz, Scott L.

    2015-06-09

    An electrochemical device having one or more solid oxide fuel cells (SOFCs), each of the SOFCs including a cathode, an anode, and an electrolyte layer positioned between the cathode and anode; and at least one additional component comprising a metallic substrate having an electronically conductive, chromium-free perovskite coating deposited directly thereon. The perovskite coating has the formula ABO.sub.3, wherein A is a lanthanide element or Y, and B is a mixture of two or more transition elements, with the A site undoped by any alkaline earth element, and the perovskite coating exhibits limited or no ionic transport of oxygen.

  20. Graded coatings for metallic implant alloys

    Energy Technology Data Exchange (ETDEWEB)

    Saiz, Eduardo; Tomsia, Antoni P.; Fujino, Shigeru; Gomez-Vega, Jose M.

    2002-08-01

    Graded glass and glass-hydroxyapatite coatings on Ti-based and Co-Cr alloys have been prepared using a simple enameling technique. The composition of the glasses has been tailored to match the thermal expansion of the alloys. By controlling the firing time, and temperature, it has been possible to control the reactivity between the glass and the alloy and to fabricate coatings (25 to 150 mu m thick) with excellent adhesion to the substrate, resistant to corrosion and able to precipitate hydroxyapatite during in vitro tests in simulated body fluid.

  1. Metallic Coatings for Graphite/Epoxy Composites

    Science.gov (United States)

    1980-08-01

    Perforated Foil-Coated Graphite/ Epoxy Panel .............. ........................... 4-6 4-4 Two-In. -Diameter 5052 Aluminum Alloy Repair Patch...The Phase I L i4-1 I1 evaluation indicated a need for a more corrosion-resistant aluminum alloy . The coating system selected was 0.0019-in. -thick 5052 ...application techniques on moisture resistance. The selected foil was 0.0025 in.-thick, 5052 aluminum alloy perforated with 0.010-in.-dlameter holes at a

  2. FUSED SALT METHOD FOR COATING URANIUM WITH A METAL

    Science.gov (United States)

    Eubank, L.D.

    1959-02-01

    A method is presented for coating uranium with a less active metal such as Cr, Ni, or Cu comprising immersing the U in a substantially anhydrous molten solution of a halide of these less active metals in a ternary chloride composition which consists of selected percentages of KCl, NaCl and another chloride such as LiCl or CaCl/sub 2/.

  3. Magnetic metal nanoparticles coated polyacrylonitrile textiles as microwave absorber

    Energy Technology Data Exchange (ETDEWEB)

    Akman, O. [Physics Department, Gebze Institute of Technology (GYTE), 41400 Gebze-Kocaeli (Turkey); Department of Physics, Sakarya University, 54100, Sakarya (Turkey); Kavas, H. [Department of Physics Engineering, Faculty of Sciences, Istanbul Medeniyet University, 34720 Istanbul (Turkey); Baykal, A., E-mail: hbaykal@fatih.edu.tr [Department of Chemistry, Fatih University, 34500, B. Cekmece-Istanbul (Turkey); Toprak, M.S. [Functional Materials Division, KTH Royal Institute of Technology, SE-16440 Stockholm (Sweden); Yildirim Beyazit University, Department of Materials Science and Engineering, Ulus-Ankara (Turkey); Coruh, Ali [Department of Physics, Sakarya University, 54100, Sakarya (Turkey); Aktas, B., E-mail: aktas@gyte.edu.tr [Physics Department, Gebze Institute of Technology (GYTE), 41400 Gebze-Kocaeli (Turkey)

    2013-02-15

    Polyacrylonitrile (PAN) textiles with 2 mm thickness are coated with magnetic nanoparticles in coating baths with Ni, Co and their alloys via an electroless metal deposition method. The crystal structure, morphology and magnetic nature of composites are investigated by X-ray Powder diffraction, Scanning Electron Microscopy, and dc magnetization measurement techniques. The frequency dependent microwave absorption measurements have been carried out in the frequency range of 12.4-18 GHz (X and P bands). Diamagnetic and ferromagnetic properties are also investigated. Finally, the microwave absorption of composites is found strongly dependent on the coating time. One absorption peak is observed between 14.3 and 15.8 GHz with an efficient absorption bandwidth of 3.3-4.1 GHz (under -20 dB reflection loss limit). The Reflection loss (RL) can be achieved between -30 and -50 dB. It was found that the RL is decreasing and absorption bandwidth is decreasing with increasing coating time. While absorption peak moves to lower frequencies in Ni coated PAN textile, it goes higher frequencies in Co coated ones. The Ni-Co alloy coated composites have fluctuating curve of absorption frequency with respect to coating time. These results encourage further development of magnetic nanoparticle coated textile absorbers for broadband applications. - Highlights: Black-Right-Pointing-Pointer Ni, Co and Ni-Co alloyed coatings on PAN were successfully prepared. Black-Right-Pointing-Pointer The incorporation of magnetic nanoparticles leads to interfacial polarization. Black-Right-Pointing-Pointer The composite prepared in Ni bath at 0.5 min leads to a wider absorption bandwidth and minimum coefficient of reflection. Black-Right-Pointing-Pointer About of -42 dB, more than 99.99% of the microwave absorption.

  4. SILANE-BASED CONVERSION COATING FOR METALS

    Science.gov (United States)

    For the past three years, a project to develop new pretreatment rinses for metals was carried out by the U.S. Environmental Protection Agency and the University of Cincinnati. The project involved optimization of laboratory rinses with dilute aqueous solutions organofunctional s...

  5. Metal Ir coatings on endocardial electrode tips, obtained by MOCVD

    Science.gov (United States)

    Vikulova, Evgeniia S.; Kal'nyi, Danila B.; Shubin, Yury V.; Kokovkin, Vasily V.; Morozova, Natalya B.; Hassan, Aseel; Basova, Tamara V.

    2017-12-01

    The present work demonstrates the application of the Metal-Organic Chemical Vapor Deposition technique to fabricate metal iridium coatings onto the pole tips of endocardial electrodes. Using iridium (III) acetylacetonate as a volatile precursor, the target coatings were successfully applied to the working surface of cathodes and anodes of pacemaker electrodes in the flow type reactor in hydrogen atmosphere at deposition temperature of 550 °C. The coating samples were characterized by means of XRD, SEM, Raman- and XPS-spectroscopies. The formation of non-textured coatings with fractal-like morphology and 7-24 nm crystallite size has been realized. The electrochemical properties of the coatings were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The charge storage capacity values of the electrochemically activated samples were 17.0-115 mC cm-2 and 14.4-76.5 mC cm-2 for measurements carried out in 0.1 M sulfuric acid and in phosphate buffer saline solutions, respectively. A comparison of some characteristics of the samples obtained with commercially available cathode of pacemaker electrodes is also presented.

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

    Science.gov (United States)

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

    2003-05-01

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

  7. Assessment of Automotive Coatings Used on Different Metallic Substrates

    Directory of Open Access Journals (Sweden)

    W. Bensalah

    2014-01-01

    Full Text Available Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of different coating systems were conducted using pin on disc machine. Immersion tests were carried out in 5% NaCl and immersion tests in 3% NaOH solutions. Results showed which of the coating systems is more suitable for each substrate in terms of mechanical, tribological, and anticorrosive performance.

  8. Assessment of Automotive Coatings Used on Different Metallic Substrates

    OpenAIRE

    Bensalah, W.; Loukil, N.; Wery, M. De-Petris; Ayedi, H. F.

    2014-01-01

    Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of ...

  9. A novel metal ion source for preparing hard coatings

    International Nuclear Information System (INIS)

    Feng, Y.C.; Wong, S.P.

    1999-01-01

    A novel metal ion source, Electron Beam Evaporation Metal Ion Source, has been developed for material modifications. This ion source is based on the electron beam evaporation technology. It can provide gaseous, solid or gaseous and solid mixed intense ion beams for preparing a variety of thin films. In this ion source, a focusing electron beam is used to bombard and vaporize the metal or other solid element within same chamber where the metal or solid atoms are ionized and plasma medium from which ions are extracted is formed by arc discharge. A small aperture diameter extraction system is used for extracting the ion beam from this source. Ion beams of a series of elements, which include C, W, Ta, Mo, Cr, Ti, B, Cu, Ni, Al, Ar, N, C+N, Ti+N, Cr+N, etc., have been extracted. The source has a 3.6 cm extraction diameter. The beam energy ranges from 0.3 to 4 keV for single charge state ions, and the maximum beam current extractable is over 90 mA. The source has been used for preparing hard coatings. The films of carbon nitride and titanium nitride have been synthesized by direct deposition with C+N and Ti+N mixed ion beams. The results have shown to exhibit very high hardness value for carbon nitride films. The microhardness is up to HK 5800 kgf/mm 2 . In comparison with other methods, it is also to exhibit higher hardness value for titanium nitride coating. The highest hardness value obtained for titanium nitride is about 3000 kgf/mm 2 . The AES profile shows that there is a good intermixture between coating and substrate for both films. The principle, structure and performance of this ion source will be described. The preliminary results for forming hard coatings are also presented in this article

  10. COATING OF POLYMERIC SUBSTRATE CATALYSTS ON METALLIC SURFACES

    Directory of Open Access Journals (Sweden)

    H. HOSSEINI

    2010-12-01

    Full Text Available This article presents results of a study on coating of a polymeric substrate ca-talyst on metallic surface. Stability of coating on metallic surfaces is a proper specification. Sol-gel technology was used to synthesize adhesion promoters of polysilane compounds that act as a mediator. The intermediate layer was coated by synthesized sulfonated polystyrene-divinylbenzene as a catalyst for production of MTBE in catalytic distillation process. Swelling of catalyst and its separation from the metal surface was improved by i increasing the quantity of divinylbenzene in the resin’s production process and ii applying adhesion pro¬moters based on the sol-gel process. The rate of ethyl silicate hydrolysis was intensified by increasing the concentration of utilized acid while the conden¬sation polymerization was enhanced in the presence of OH–. Sol was formed at pH 2, while the pH should be 8 for the formation of gel. By setting the ratio of the initial concentrations of water to ethyl silicate to 8, the gel formation time was minimized.

  11. Interaction of beam and coated metals at high power continuous irradiation

    Science.gov (United States)

    Kim, Yong Hyeon; Baek, Won-Kye; Yoh, Jack J.

    2011-07-01

    The beam-matter interaction with various coating effects has received continued attention in the high power laser community. Previous works suggest that coatings promote target damage when compared to beaming on uncoated surface. Three types of paint coatings (acrylic urethane, silicone alkyd and stealth blend) and a water coat on metals (Al, Ti and STS) are irradiated with a CO 2 laser. Both strain and temperature measurements are provided for assessing the instantaneous response characteristics of each coating on different metals. A selective combination of surface coats with metals has been proven to be effective in either preventing or enhancing damage, both thermal and mechanical, associated with focused beaming on a target.

  12. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Science.gov (United States)

    2010-04-01

    ... porous-coated uncemented prosthesis. 888.3565 Section 888.3565 Food and Drugs FOOD AND DRUG... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

  13. Humidity Detection Using Metal Organic Framework Coated on QCM

    KAUST Repository

    Kosuru, Lakshmoji

    2016-06-28

    Quartz crystal microbalance (QCM) coated with poly-4-vinylpyridine (PVP) and metal organic framework HKUST-1 are investigated and compared for humidity sensing. Drop casting method is employed to coat the PVP and HKUST-1 solutions onto the surface of a quartz crystal microbalance. The resonance frequencies of these sensors with varying relative humidity (RH) from 22% RH to 69% RH are measured using impedance analysis method. The sensitivity, humidity hysteresis, response, and recovery times of these sensors are studied. The sensitivities of uncoated, PVP, and HKUST-1 coated QCM sensors are 7 Hz, 48 Hz, and 720 Hz, respectively, in the range of 22% RH–69% RH. The extraction of desorption rate and adsorption energy associated with the adsorption and desorption of water molecules on these surfaces reveals that HKUST-1 has better sensing properties than PVP and uncoated QCM sensors. In this work, the HKUST-1 coated QCM is shown to be a promising material for moisture detection.

  14. Humidity Detection Using Metal Organic Framework Coated on QCM

    Directory of Open Access Journals (Sweden)

    Lakshmoji Kosuru

    2016-01-01

    Full Text Available Quartz crystal microbalance (QCM coated with poly-4-vinylpyridine (PVP and metal organic framework HKUST-1 are investigated and compared for humidity sensing. Drop casting method is employed to coat the PVP and HKUST-1 solutions onto the surface of a quartz crystal microbalance. The resonance frequencies of these sensors with varying relative humidity (RH from 22% RH to 69% RH are measured using impedance analysis method. The sensitivity, humidity hysteresis, response, and recovery times of these sensors are studied. The sensitivities of uncoated, PVP, and HKUST-1 coated QCM sensors are 7 Hz, 48 Hz, and 720 Hz, respectively, in the range of 22% RH–69% RH. The extraction of desorption rate and adsorption energy associated with the adsorption and desorption of water molecules on these surfaces reveals that HKUST-1 has better sensing properties than PVP and uncoated QCM sensors. In this work, the HKUST-1 coated QCM is shown to be a promising material for moisture detection.

  15. Origin of Shear Stability and Compressive Ductility Enhancement of Metallic Glasses by Metal Coating

    Science.gov (United States)

    Sun, B. A.; Chen, S. H.; Lu, Y. M.; Zhu, Z. G.; Zhao, Y. L.; Yang, Y.; Chan, K. C.; Liu, C. T.

    2016-01-01

    Metallic glasses (MGs) are notorious for the poor macroscopic ductility and to overcome the weakness various intrinsic and extrinsic strategies have been proposed in past decades. Among them, the metal coating is regarded as a flexible and facile approach, yet the physical origin is poorly understood due to the complex nature of shear banding process. Here, we studied the origin of ductile enhancement in the Cu-coating both experimentally and theoretically. By examining serrated shear events and their stability of MGs, we revealed that the thin coating layer plays a key role in stopping the final catastrophic failure of MGs by slowing down shear band dynamics and thus retarding its attainment to a critical instable state. The mechanical analysis on interplay between the coating layer and shear banding process showed the enhanced shear stability mainly comes from the lateral tension of coating layer induced by the surface shear step and the bonding between the coating layer and MGs rather than the layer thickness is found to play a key role in contributing to the shear stability. PMID:27271435

  16. Graphitization of diamond with a metallic coating on ferritic matrix

    International Nuclear Information System (INIS)

    Cabral, Stenio Cavalier; Oliveira, Hellen Cristine Prata de; Filgueira, Marcello

    2010-01-01

    Iron is a strong catalyst of graphitization of diamonds. This graphitization occurs mainly during the processing of composites - conventional sintering or hot pressing, and during cutting operations. Aiming to avoid or minimize this deleterious effect, there is increasing use of diamond coated with metallic materials in the production of diamond tools processed via powder metallurgy. This work studies the influence of Fe on diamond graphitization diamond-coated Ti after mixing of Fe-diamonds, hot pressing parameters were performed with 3 minutes/35MPa/900 deg C - this is the condition of pressing hot used in industry for production of diamond tools. Microstructural features were observed by SEM, diffusion of Fe in diamond was studied by EDS. Graphitization was analyzed by X-ray diffraction and Raman spectroscopy. It was found that Fe not activate graphitization on the diamond under the conditions of hot pressing. (author)

  17. Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

    OpenAIRE

    Ramm , D.; Hutchings , I.; Clyne , T.

    1993-01-01

    Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharp...

  18. Protective coatings of metal surfaces by cold plasma treatment

    Science.gov (United States)

    Manory, R.; Grill, A.

    1985-01-01

    The cold plasma techniques for deposition of various types of protective coatings are reviewed. The main advantage of these techniques for deposition of ceramic films is the lower process temperature, which enables heat treating of the metal prior to deposition. In the field of surface hardening of steel, significant reduction of treatment time and energy consumption were obtained. A simple model for the plasma - surface reactions in a cold plasma system is presented, and the plasma deposition techniques are discussed in view of this model.

  19. Novel Chemical Process for Producing Chrome Coated Metal

    Directory of Open Access Journals (Sweden)

    Christopher Pelar

    2018-01-01

    Full Text Available This work demonstrates that a version of the Reduction Expansion Synthesis (RES process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM. SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

  20. Novel Chemical Process for Producing Chrome Coated Metal.

    Science.gov (United States)

    Pelar, Christopher; Greenaway, Karima; Zea, Hugo; Wu, Chun-Hsien; Luhrs, Claudia C; Phillips, Jonathan

    2018-01-05

    This work demonstrates that a version of the Reduction Expansion Synthesis (RES) process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM). SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

  1. Multifunctional methacrylate-based coatings for glass and metal surfaces

    Science.gov (United States)

    Pospiech, Doris; Jehnichen, Dieter; Starke, Sandra; Müller, Felix; Bünker, Tobias; Wollenberg, Anne; Häußler, Liane; Simon, Frank; Grundke, Karina; Oertel, Ulrich; Opitz, Michael; Kruspe, Rainer

    2017-03-01

    In order to prevent freshwater biofouling glass and metal surfaces were coated with novel transparent methacrylate-based copolymers. The multifunctionality of the copolymers, such as adhesion to the substrate, surface polarity, mechanical long-term stability in water, and ability to form metal complexes was inserted by the choice of suitable comonomers. The monomer 2-acetoacetoxy ethyl methacrylate (AAMA) was used as complexing unit to produce copper(II) complexes in the coating's upper surface layer. The semifluorinated monomer 1H,1H,2H,2H-perfluorodecyl methacrylate was employed to adjust the surface polarity and wettability. Comprehensive surface characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that surface compositions and properties can be easily adjusted by varying the concentrations of the comonomers. The formation of copper(II) complexes along the copolymer chains and their stability against washing out with plenty of water was proven by XPS. Copolymers containing semifluorinated comonomers significantly inhibited the growth of Achnanthidium species. Copolymers with copper-loaded AAMA-sequences were able to reduce both the growth of Achnanthidium spec. and Staphylococcus aureus.

  2. Multifunctional methacrylate-based coatings for glass and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pospiech, Doris, E-mail: pospiech@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Jehnichen, Dieter [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Starke, Sandra; Müller, Felix [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Technische Universität Dresden, Organic Chemistry of Polymers, Dresden (Germany); Bünker, Tobias [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Wollenberg, Anne [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Technische Universität Dresden, Organic Chemistry of Polymers, Dresden (Germany); Häußler, Liane; Simon, Frank; Grundke, Karina; Oertel, Ulrich [Leibniz-Institut für Polymerforschung Dresden e. V., Dresden (Germany); Opitz, Michael; Kruspe, Rainer [IDUS Biologisch Analytisches Umweltlabor GmbH, Ottendorf-Okrilla (Germany)

    2017-03-31

    Highlights: • New methacrylate-based copolymers synthesized by free radical polymerization. • Comonomer AAMA was able to complex Cu (II) ions in solvent annealing procedure. • Coatings had efficient anti-biofouling efficacy. - Abstract: In order to prevent freshwater biofouling glass and metal surfaces were coated with novel transparent methacrylate-based copolymers. The multifunctionality of the copolymers, such as adhesion to the substrate, surface polarity, mechanical long-term stability in water, and ability to form metal complexes was inserted by the choice of suitable comonomers. The monomer 2-acetoacetoxy ethyl methacrylate (AAMA) was used as complexing unit to produce copper(II) complexes in the coating’s upper surface layer. The semifluorinated monomer 1H,1H,2H,2H-perfluorodecyl methacrylate was employed to adjust the surface polarity and wettability. Comprehensive surface characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that surface compositions and properties can be easily adjusted by varying the concentrations of the comonomers. The formation of copper(II) complexes along the copolymer chains and their stability against washing out with plenty of water was proven by XPS. Copolymers containing semifluorinated comonomers significantly inhibited the growth of Achnanthidium species. Copolymers with copper-loaded AAMA-sequences were able to reduce both the growth of Achnanthidium spec. and Staphylococcus aureus.

  3. Multifunctional methacrylate-based coatings for glass and metal surfaces

    International Nuclear Information System (INIS)

    Pospiech, Doris; Jehnichen, Dieter; Starke, Sandra; Müller, Felix; Bünker, Tobias; Wollenberg, Anne; Häußler, Liane; Simon, Frank; Grundke, Karina; Oertel, Ulrich; Opitz, Michael; Kruspe, Rainer

    2017-01-01

    Highlights: • New methacrylate-based copolymers synthesized by free radical polymerization. • Comonomer AAMA was able to complex Cu (II) ions in solvent annealing procedure. • Coatings had efficient anti-biofouling efficacy. - Abstract: In order to prevent freshwater biofouling glass and metal surfaces were coated with novel transparent methacrylate-based copolymers. The multifunctionality of the copolymers, such as adhesion to the substrate, surface polarity, mechanical long-term stability in water, and ability to form metal complexes was inserted by the choice of suitable comonomers. The monomer 2-acetoacetoxy ethyl methacrylate (AAMA) was used as complexing unit to produce copper(II) complexes in the coating’s upper surface layer. The semifluorinated monomer 1H,1H,2H,2H-perfluorodecyl methacrylate was employed to adjust the surface polarity and wettability. Comprehensive surface characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that surface compositions and properties can be easily adjusted by varying the concentrations of the comonomers. The formation of copper(II) complexes along the copolymer chains and their stability against washing out with plenty of water was proven by XPS. Copolymers containing semifluorinated comonomers significantly inhibited the growth of Achnanthidium species. Copolymers with copper-loaded AAMA-sequences were able to reduce both the growth of Achnanthidium spec. and Staphylococcus aureus.

  4. Amorphous metal formulations and structured coatings for corrosion and wear resistance

    Science.gov (United States)

    Farmer, Joseph C [Tracy, CA

    2011-12-13

    A system for coating a surface comprising providing a source of amorphous metal that contains more than 11 elements and applying the amorphous metal that contains more than 11 elements to the surface by a spray. Also a coating comprising a composite material made of amorphous metal that contains more than 11 elements. An apparatus for producing a corrosion-resistant amorphous-metal coating on a structure comprises a deposition chamber, a deposition source in the deposition chamber that produces a deposition spray, the deposition source containing a composite material made of amorphous metal that contains more than 11 elements, and a system that directs the deposition spray onto the structure.

  5. Platinum-coated non-noble metal-noble metal core-shell electrocatalysts

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir

    2015-04-14

    Core-shell particles encapsulated by a thin film of a catalytically active metal are described. The particles are preferably nanoparticles comprising a non-noble core with a noble metal shell which preferably do not include Pt. The non-noble metal-noble metal core-shell nanoparticles are encapsulated by a catalytically active metal which is preferably Pt. The core-shell nanoparticles are preferably formed by prolonged elevated-temperature annealing of nanoparticle alloys in an inert environment. This causes the noble metal component to surface segregate and form an atomically thin shell. The Pt overlayer is formed by a process involving the underpotential deposition of a monolayer of a non-noble metal followed by immersion in a solution comprising a Pt salt. A thin Pt layer forms via the galvanic displacement of non-noble surface atoms by more noble Pt atoms in the salt. The overall process is a robust and cost-efficient method for forming Pt-coated non-noble metal-noble metal core-shell nanoparticles.

  6. On metallic gratings coated conformally with isotropic negative-phase-velocity materials

    Energy Technology Data Exchange (ETDEWEB)

    Inchaussandague, Marina E. [GEA-Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); CONICET-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Rivadavia 1917, Buenos Aires (Argentina)], E-mail: mei@df.uba.ar; Lakhtakia, Akhlesh [CATMAS-Computational and Theoretical Materials Sciences Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States)], E-mail: akhlesh@psu.edu; Depine, Ricardo A. [GEA-Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); CONICET-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Rivadavia 1917, Buenos Aires (Argentina)], E-mail: rdep@df.uba.ar

    2008-03-31

    Application of the differential method (also called the C method) to plane-wave diffraction by a perfectly conducting, sinusoidally corrugated metallic grating coated with a linear, homogeneous, isotropic, lossless dielectric-magnetic material shows that coating materials with negative index of refraction may deliver enhanced maximum nonspecular reflection efficiencies in comparison to coating materials with positive index of refraction.

  7. Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

    International Nuclear Information System (INIS)

    Ramm, D.A.J.; Hutchings, I.M.; Clyne, T.W.

    1993-01-01

    Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharply reducing the erosive wear at high erodent impact angles, whilst retaining the good erosion resistance of ceramics at low angles. It is shown that the proportion of metal and ceramic at the free surface can be specified so as to optimise the erosion resistance. Experiments have also been carried out on the resistance of the coatings to debonding during four-point bending of the coated substrate. Progress is being made towards the tailoring of composition profiles in graded coatings so as to optimise the combination of erosion resistance and adhesion. (orig.)

  8. Metal matrix coated fiber composites and the methods of manufacturing such composites

    Science.gov (United States)

    Weeks, J.K. Jr.; Gensse, C.

    1993-09-14

    A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials. 8 figures.

  9. Metals and the Integrity of a Biological Coating

    Science.gov (United States)

    Holten-Andersen, Niels; Mates, Thomas E.; Toprak, Muhammet S.; Stucky, Galen D.; Zok, Frank W.; Waite, J. Herbert

    2009-01-01

    The cuticle of mussel byssal threads is a robust natural coating that combines high extensibility with high stiffness and hardness. In this study, fluorescence microscopy and elemental analysis were exploited to show that the 3,4-dihydroxyphenyl-l-alanine (dopa) residues of mussel foot protein-1 colocalize with Fe and Ca distributions in the cuticle of Mytilus galloprovincialis mussel byssal threads. Chelated removal of Fe and Ca from the cuticle of intact threads resulted in a 50% reduction in cuticle hardness, and thin sections subjected to the same treatment showed a disruption of cuticle integrity. Dopa-metal complexes may provide significant interactions for the integrity of composite cuticles deformed under tension. PMID:18847291

  10. Metal coatings prepared by organometallic chemical vapour deposition (OMCVD)

    Energy Technology Data Exchange (ETDEWEB)

    Wochnowski, Joern; Heck, Juergen [Institute of Inorganic and Applied Chemistry, Hamburg (Germany); Goellnitz, Thimo [Institute of Inorganic and Applied Chemistry, Hamburg (Germany); Institute of Applied Physics, University of Hamburg (Germany); Hoffmann, Germar; Wiesendanger, Roland [Institute of Applied Physics, University of Hamburg (Germany)

    2008-07-01

    In microtechnology, the coating of temperature-sensitive substrates with high melting-point materials is challenging. The use of volatile organometallic compounds can be an answer to solve this ambitious task. We developed an experimental set-up for the deposition of elements, oxides, and functional composites in glass hollowware by means of OMCVD. With the first experimental set-up, the thermally induced decomposition of numerous elementorganic and metallorganic precursors has been tested for the deposition of catalytic or optic materials. Here, we present experimental data of the thermal deposition of different metals as tungsten on a glass surface. We used Atomic Force Microscopy as one standard analytical surface method to obtain structural and morphological information of the deposited metal layers. We discuss the preparation and the analytics of the prepared surfaces. With the objective to bring the deposition temperature of W(CO){sub 6} further down to room temperature, we developed a new photolytic OMCVD set-up. We demonstrate and discuss the realization of our experimental setup.

  11. Effect of Zinc Phosphate on the Corrosion Behavior of Waterborne Acrylic Coating/Metal Interface

    Directory of Open Access Journals (Sweden)

    Hongxia Wan

    2017-06-01

    Full Text Available Waterborne coating has recently been paid much attention. However, it cannot be used widely due to its performance limitations. Under the specified conditions of the selected resin, selecting the function pigment is key to improving the anticorrosive properties of the coating. Zinc phosphate is an environmentally protective and efficient anticorrosion pigment. In this work, zinc phosphate was used in modifying waterborne acrylic coatings. Moreover, the disbonding resistance of the coating was studied. Results showed that adding zinc phosphate can effectively inhibit the anode process of metal corrosion and enhance the wet adhesion of the coating, and consequently prevent the horizontal diffusion of the corrosive medium into the coating/metal interface and slow down the disbonding of the coating.

  12. Effect of Zinc Phosphate on the Corrosion Behavior of Waterborne Acrylic Coating/Metal Interface.

    Science.gov (United States)

    Wan, Hongxia; Song, Dongdong; Li, Xiaogang; Zhang, Dawei; Gao, Jin; Du, Cuiwei

    2017-06-14

    Waterborne coating has recently been paid much attention. However, it cannot be used widely due to its performance limitations. Under the specified conditions of the selected resin, selecting the function pigment is key to improving the anticorrosive properties of the coating. Zinc phosphate is an environmentally protective and efficient anticorrosion pigment. In this work, zinc phosphate was used in modifying waterborne acrylic coatings. Moreover, the disbonding resistance of the coating was studied. Results showed that adding zinc phosphate can effectively inhibit the anode process of metal corrosion and enhance the wet adhesion of the coating, and consequently prevent the horizontal diffusion of the corrosive medium into the coating/metal interface and slow down the disbonding of the coating.

  13. New oxide-composite coatings for difficult metal-cutting tasks

    International Nuclear Information System (INIS)

    Westphal, H.; Berg, H. van den; Sottke, V.; Tabersky, R.

    2001-01-01

    The changes in today's metal working technology are driven by increasing cutting speeds, heavy/hard machining and an enormous amount by changes in work piece materials. These applications are asking for more tailor made cutting tool solutions. Together with the well established multi component coating technology a new approach of composite coatings is giving solutions for the tough demands of the cutting tool market. In this paper is presented composite coatings of AI 2 O 3 /ZrO-2/TiO x made by CVD. The coating is like high performance oxide ceramics for cutting applications. The coating is used in combination with MT CVD coatings and different carbide substrates. The CVD coating has optimum stress for cutting applications, low friction and very high thermal isolation. The outstanding performance of this coating is demonstrated in different applications. (author)

  14. Non-stick syringe needles: Beneficial effects of thin film metallic glass coating

    OpenAIRE

    Chu, Jinn P.; Yu, Chia-Chi; Tanatsugu, Yusuke; Yasuzawa, Mikito; Shen, Yu-Lin

    2016-01-01

    This paper reports on the use of Zr-based (Zr53Cu33Al9Ta5) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ?66% and retraction forces by ?72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings ...

  15. Gas phase deposition of oxide and metal-oxide coatings on fuel particles

    International Nuclear Information System (INIS)

    Patokin, A.P.; Khrebtov, V.L.; Shirokov, B.M.

    2008-01-01

    Production processes and properties of oxide (Al 2 O 3 , ZrO 2 ) and metal-oxide (Mo-Al 2 O 3 , Mo-ZrO 2 , W-Al 2 O 3 , W-ZrO 2 ) coatings on molybdenum substrates and uranium dioxide fuel particles were investigated. It is shown that the main factors that have an effect on the deposition rate, density, microstructure and other properties of coatings are the deposition temperature, the ratio of H 2 and CO 2 flow rates, the total reactor pressure and the ratio of partial pressures of corresponding metal chlorides during formation of metal-oxide coatings

  16. Durable Dust Repellent Coating for Metals, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Durable Dust Repellent Coating (DDRC) consists of nano-phase silica, titania, or other oxide coatings to repel dust in a vacuum environment over a wide range of...

  17. High Transparent Metal Oxide / Polyimide Antistatic Coatings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA requires clear antistatic coatings that can withstand exposure to the rigors of the space environment. Agiltron proposes a coating consisting of inorganic...

  18. Calcium and Zinc Containing Bactericidal Glass Coatings for Biomedical Metallic Substrates

    Directory of Open Access Journals (Sweden)

    Leticia Esteban-Tejeda

    2014-07-01

    Full Text Available The present work presents new bactericidal coatings, based on two families of non-toxic, antimicrobial glasses belonging to B2O3–SiO2–Na2O–ZnO and SiO2–Na2O–Al2O3–CaO–B2O3 systems. Free of cracking, single layer direct coatings on different biomedical metallic substrates (titanium alloy, Nb, Ta, and stainless steel have been developed. Thermal expansion mismatch was adjusted by changing glass composition of the glass type, as well as the firing atmosphere (air or Ar according to the biomedical metallic substrates. Formation of bubbles in some of the glassy coatings has been rationalized considering the reactions that take place at the different metal/coating interfaces. All the obtained coatings were proven to be strongly antibacterial versus Escherichia coli (>4 log.

  19. Development of Ceramic Coating on Metal Substrate using Industrial Waste and Ore Minerals

    Science.gov (United States)

    Bhuyan, S. K.; Thiyagarajan, T. K.; Mishra, S. C.

    2017-02-01

    The technological advancement in modern era has a boon for enlightening human life; but also is a bane to produce a huge amount of (industrial) wastes, which is of great concern for utilization and not to create environmental threats viz. polution etc. In the present piece of research work, attempts have been made to utilize fly ash (wastes of thermal power plants) and along with alumina bearing ore i.e. bauxite, for developing plasma spray ceramic coatings on metals. Fly ash and with 10 and 20% bauxite addition is used to deposit plasma spray coatings on a metal substrate. The surface morphology of the coatings deposited at different power levels of plasma spraying investigated through SEM and EDS analysis. The coating thickness is measured. The porosity levels of the coatings are evaluated. The coating hardness isalso measured. This piece of research work will be beneficial for future development and use of industrial waste and ore minerals for high-valued applications.

  20. Coatings of metal substrates assisted by laser radiation

    Directory of Open Access Journals (Sweden)

    Caudevilla, H.

    1998-04-01

    Full Text Available In this contribution, a new way of obtaining ceramic coatings is presented. This method uses precursor suspensions, settled on substrates and in-situ pyrolised with a laser. Different deposition techniques of the ceramic precursors have been tested in order to obtain a homogeneous distribution on the metal substrate before the laser treatment.

    La combinación de recubrimientos utilizando disoluciones de precursores metálicos con la pirólisis asistida por láser, permite obtener una gran diversidad de recubrimientos sobre sustratos de muy distinta naturaleza. Se han realizado estudios, tanto con disoluciones poliméricas, como con disoluciones de tipo sol-gel y pastas obtenidas con técnicas similares, depositadas utilizando métodos convencionales de inmersión y atomización previa a la pirólisis asistida por láser, así como simultánea. En este trabajo se presenta un resumen de los resultados más significativos obtenidos en la realización de recubrimientos sobre sustratos metálicos y cerámicos.

  1. Facilitation of trace metal uptake in cells by inulin coating of metallic nanoparticles

    Science.gov (United States)

    Santillán-Urquiza, Esmeralda; Arteaga-Cardona, Fernando; Torres-Duarte, Cristina; Cole, Bryan; Wu, Bing; Méndez-Rojas, Miguel A.; Cherr, Gary N.

    2017-09-01

    Trace elements such as zinc and iron are essential for the proper function of biochemical processes, and their uptake and bioavailability are dependent on their chemical form. Supplementation of trace metals through nanostructured materials is a new field, but its application raises concerns regarding their toxicity. Here, we compared the intracellular zinc uptake of different sources of zinc: zinc sulfate, and ZnO and core-shell α-Fe2O3@ZnO nanoparticles, coated or uncoated with inulin, an edible and biocompatible polysaccharide. Using mussel haemocytes, a well-known model system to assess nanomaterial toxicity, we simultaneously assessed zinc accumulation and multiple cellular response endpoints. We found that intracellular zinc uptake was strongly enhanced by inulin coating, in comparison to the uncoated nanoparticles, while no significant effects on cell death, cell viability, mitochondrial membrane integrity, production of reactive oxygen species or lysosome abundance were observed at concentrations up to 20 ppm. Since no significant increments in toxicity were observed, the coated nanomaterials may be useful to increase in vivo zinc uptake for nutritional applications.

  2. Failure of aluminium metal spray/organic duplex coating systems on structural steel

    OpenAIRE

    Sumon, T. A.; Scantlebury, J. D.; Lyon, S. B.

    2013-01-01

    Individually, aluminium metal spray (AMS) and organic paints are well established as effective protective coatings for steel substrates. These coatings are also frequently used together as duplex systems where their combination should produce a synergistic effect. However in certain, mainly marine, environments premature failure of such coatings, involving early blistering of the paint, has been observed in service after 3-5 years. This work aims to understand the mechanisms associated with t...

  3. Novel Base Metal-Palladium Catalytic Diesel Filter Coating with NO2 Reducing Properties

    DEFF Research Database (Denmark)

    Johansen, K.; Dahl, S.; Mogensen, G.

    2007-01-01

    A novel alternative base metal/palladium coat has been developed that has limited NO2 formation and which even removes NO2 in a wide temperature range.Soot combustion, HC conversion and CO conversion properties are comparable to current platinum based solutions but the coating has a more attracti...

  4. Effect of a dielectric coating on terahertz surface plasmon polaritons on metal wires

    NARCIS (Netherlands)

    Van der Valk, N.C.J.; Planken, P.C.M.

    2005-01-01

    The authors present measurements and calculations on the effect of thin dielectric coatings on the propagation of terahertz pulses along the surface of metal wires. Our measurements show that propagation over only a few centimeters of wire having a thin dielectric coating, strongly distorts the

  5. Durable hydrophobic coating composition for metallic surfaces and method for the preparation of the composition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiong

    2017-02-14

    A durable hydrophobic coating composition containing fluorinated silanes for metallic surfaces, such as stainless steel surfaces. The composition includes at least one fluorine-containing silane compound, at least one phosphorus-containing silane compound, and at least one hydrolysable compound. This coating is suitable for condenser tubes, among other applications, to promote dropwise condensation.

  6. 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...

  7. Non-stick syringe needles: Beneficial effects of thin film metallic glass coating.

    Science.gov (United States)

    Chu, Jinn P; Yu, Chia-Chi; Tanatsugu, Yusuke; Yasuzawa, Mikito; Shen, Yu-Lin

    2016-08-30

    This paper reports on the use of Zr-based (Zr53Cu33Al9Ta5) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ∼66% and retraction forces by ∼72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings achieved a coefficient of friction (COF) of just ∼0.05, which is about one order of magnitude lower than those of other coatings. Finite-element modeling also indicates a significant reduction in injection and retraction forces. The COF can be attributed to the absence of grain boundaries in the TFMG coating as well as a smooth surface morphology and low surface free energy.

  8. A Comparative Study of Natural Fiber and Glass Fiber Fabrics Properties with Metal or Oxide Coatings

    International Nuclear Information System (INIS)

    Lusis, Andrej; Pentjuss, Evalds; Bajars, Gunars; Sidorovicha, Uljana; Strazds, Guntis

    2015-01-01

    Rapidly growing global demand for technical textiles industries is stimulated to develop new materials based on hybrid materials (yarns, fabrics) made from natural and glass fibres. The influence of moisture on the electrical properties of metal and metal oxide coated bast (flax, hemp) fibre and glass fibre fabrics are studied by electrical impedance spectroscopy and thermogravimetry. The bast fibre and glass fiber fabrics are characterized with electrical sheet resistance. The method for description of electrical sheet resistance of the metal and metal oxide coated technical textile is discussed. The method can be used by designers to estimate the influence of moisture on technical data of new metal coated hybrid technical textile materials and products

  9. Electrically Conductive, Corrosion-Resistant Coatings Through Defect Chemistry for Metallic Interconnects

    International Nuclear Information System (INIS)

    Anil V. Virkar

    2006-01-01

    The principal objective of this work was to develop oxidation protective coatings for metallic interconnect based on a defect chemistry approach. It was reasoned that the effectiveness of a coating is dictated by oxygen permeation kinetics; the slower the permeation kinetics, the better the protection. All protective coating materials investigated to date are either perovskites or spinels containing metals exhibiting multiple valence states (Co, Fe, Mn, Cr, etc.). As a result, all of these oxides exhibit a reasonable level of electronic conductivity; typically at least about ∼0.05 S/cm at 800 C. For a 5 micron coating, this equates to a maximum ∼0.025 (Omega)cm 2 area specific resistance due to the coating. This suggests that the coating should be based on oxygen ion conductivity (the lower the better) and not on electronic conductivity. Measurements of ionic conductivity of prospective coating materials were conducted using Hebb-Wagner method. It was demonstrated that special precautions need to be taken to measure oxygen ion conductivity in these materials with very low oxygen vacancy concentration. A model for oxidation under a protective coating is presented. Defect chemistry based approach was developed such that by suitably doping, oxygen vacancy concentration was suppressed, thus suppressing oxygen ion transport and increasing effectiveness of the coating. For the cathode side, the best coating material identified was LaMnO 3 with Ti dopant on the Mn site (LTM). It was observed that LTM is more than 20 times as effective as Mn-containing spinels. On the anode side, LaCrO3 doped with Nb on the Cr site (LNC) was the material identified. Extensive oxidation kinetics studies were conducted on metallic alloy foils with coating ∼1 micron in thickness. From these studies, it was projected that a 5 micron coating would be sufficient to ensure 40,000 h life

  10. 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.

  11. Forming of protective nanostructure coatings on metals and glasses and their properties investigation

    International Nuclear Information System (INIS)

    Deshkovskaya, A.; Lynkov, L.; Nagibarov, A.; Glybin, V.; Richter, E.; Pham, M.

    2013-01-01

    Transparent heat-resistant coatings of 10-30 nm thickness described by (ZrO 2 ) x •(Y 2 O 3 ) y composition are formed on the surface of metals and glasses by thermolysis technique. Produced coatings possess high adhesive strength, high corrosive and abrasive resistance. Nanocrystalline formations are revealed on samples surface, with quantity of these formations depending on basic solution concentration, formed layers number and thermal treatment mode. Ion-beam modification of obtained coatings under mixing mode enables said properties enhancing owing to zirconium oxiboride formation at substrate-coating interface as a result of ion-beam synthesis. (authors)

  12. Hard Chrome-Coated and Fullerene-Doped Metal Surfaces in Orthopedic Bearings.

    Science.gov (United States)

    Sonntag, Robert; Feige, Katja; Dos Santos, Claudia Beatriz; Kretzer, Jan Philippe

    2017-12-20

    Metal-on-metal bearings for total hip replacements have been introduced as an alternative to polyethylene in young and more active patients. These have, however, been shown to be prone to implant malpositioning and have been limited by some specific design features. In that context, coatings present an option to increase wear resistance by keeping the high fracture strength of the metal substrate. A custom-made electroplating setup was designed for the coating of CoCr substrates using (a) an industrial standard chromium electrolyte; (b) a custom-made hexavalent chromium (Cr 6+ ) electrolyte with a reduced chromium trioxide (CrO₃) content, both without solid additives and (c) with the addition of fullerene (C 60 ) nanoparticles; and (d) a trivalent chromium (Cr 3+ ) electrolyte with C 60 addition. All coatings showed an increase in microhardness compared with the metal substrate. Trivalent coatings were thinner (10 µm) than the hexavalent coatings (23-40 µm) and resulted in increased roughness and crack density. Wear was found to be reduced for the hexavalent chromium coatings by 70-84% compared with the CoCr-CoCr reference bearing while the trivalent chromium coating even increased wear by more than 300%. The addition of fullerenes to the electrolyte did not show any further tribological effect.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  15. Refractory metal carbide coatings for LMFBR applications: a systems approach

    International Nuclear Information System (INIS)

    Gotschall, H.L.; Ople, F.S.; Riccardella, P.C.

    1975-01-01

    The selection, testing and improvement of high density, tightly bonded plasma and detonation gun coatings designed to meet LMFBR core component criteria are described. The process descriptions include a review of the important developments in substrate surface preparation which were required to ensure strong bonding and to minimize interface contamination. Coating finishing techniques which were developed to optimize friction behavior are also described

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

    OpenAIRE

    Chun, Hui Gon; Cho, Tong Yul; Yoon, Jae Hong; Lee, Gun Hwan

    2015-01-01

    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. ...

  17. Controlling the plasmon resonance wavelength in metal-coated probe using refractive index modification.

    Science.gov (United States)

    Taguchi, Atsushi; Hayazawa, Norihiko; Saito, Yuika; Ishitobi, Hidekazu; Tarun, Alvarado; Kawata, Satoshi

    2009-04-13

    We present a novel technique to tune the plasmon resonance of metal-coated silicon tips in the whole visible region without altering the tips original sharpness. The technique involves modification of the refractive index of silicon probe by thermal oxidization. Lowering the refractive index of silicon tip coated with metal shift the PRW of the metallic layer to shorter wavelength. Numerical simulation using FDTD agrees well with the empirical results. This novel technique is very useful in tip-enhanced Raman spectroscopy studies of various materials because plasmon resonance can tuned to a specific Raman excitation wavelength.

  18. Slurry erosion and abrasion of metal-ceramic coatings

    International Nuclear Information System (INIS)

    Sagues, A.A.; Spencer, D.K.; Sethi, V.K.; Sargent, G.A.

    1987-01-01

    Four coatings, including tungsten carbide wear-resistant and cobalt-base corrosion-resistant materials, were tested for abrasion and erosion performance in silica sand and in Alundum slurries. A 1018 carbon steel sample was also tested for comparison. The abrasion tests were conducted with a wet sand rubber wheel device, whereas a slurry jet impingement apparatus was used in the erosion tests. The results revealed that the abrasive wear performance improves dramatically as the coating hardness increases. By contrast, the erosion performance was not clearly related to the hardness of the materials tested. The wear mechanisms and the suitability of the test methods to evaluate coatings are discussed

  19. Water-Based Assembly of Polymer-Metal Organic Framework (MOF) Functional Coatings

    Energy Technology Data Exchange (ETDEWEB)

    De, Souvik [Artie McFerrin Department of Chemical Engineering, Texas A& M University, 77843-3122 TAMU College Station TX 77843-3122 USA; Nandasiri, Manjula I. [Environmental Molecular Sciences Laboratory (EMSL), Pacific Northwest National Laboratory, Richland WA 99352 USA; Schaef, Herbert T. [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; McGrail, Benard Peter [Energy & Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99352 USA; Nune, Satish K. [Energy & Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99352 USA; Lutkenhaus, Jodie L. [Artie McFerrin Department of Chemical Engineering, Texas A& M University, 77843-3122 TAMU College Station TX 77843-3122 USA; Department of Materials Science & Engineering, Texas A& M University, 3122 TAMU College Station TX 77843-3122 USA

    2016-12-27

    Metal organic frameworks (MOFs) have gained tremendous attention for their porosity, size selectivity, and structural diversity. There is a need for MOF-based coatings, particularly in applications such as separations, electronics and energy; yet forming thin, functional, conformal coatings is prohibitive because MOFs exist as a powder. Layer-by- layer assembly, a versatile thin film coating approach, offers a unique solution to this problem, but this approach requires MOFs that are water-dispersible and bear a surface charge. Here, we address these issues by examining water-based dispersions of MIL-101(Cr) that facilitate the formation of robust polymer-MOF hybrid coatings. Specifically, the substrate to be coated is alternately exposed to an aqueous solution of poly(styrene sulfonate) and dispersion MIL-101(Cr), yielding linear film growth and coatings with a MOF content as high as 77 wt%.This approach is surface-agnostic, in which the coating is successfully applied to silicon, glass, flexible plastic, and even cotton fabric, conformally coating individual fibers. In contrast, prior attempts at forming MOF-coatings were severely limited to a handful of surfaces, required harsh chemical treatment, and were not conformal. The approach presented here unambiguously confirms that MOFs can be conformally coated onto complex and unusual surfaces, opening the door for a wide variety of applications.

  20. Transfer of Wire Arc-Sprayed Metal Coatings onto Plastic Parts

    Science.gov (United States)

    Bobzin, K.; Öte, M.; Knoch, M. A.; Liao, X.; Hopmann, Ch.; Ochotta, P.

    2018-01-01

    By means of In-Mold-Metal-Spraying (IMMS), metal coatings deposited by means of arc spraying process (ASP) can be transferred onto plastic parts during injection molding, thus realizing an efficient production of metallized plastic parts. Parts produced by means of IMMS can be used in electrical applications. In the current study, the electrical resistivity of coatings applied with different feedstock materials was determined. As a starting point, pressurized air is used as atomizing gas for ASP. In contrast to Zn coatings, Cu coatings applied with pressurized air exhibit a significantly higher electrical resistivity in comparison with massive material. One possible reason is the more pronounced oxidation of Cu particles during ASP. Therefore, N2 and a mixture of N2 and H2 were used as atomizing gas. As a result, the electrical resistivity of coatings applied by means of IMMS could be significantly reduced. Furthermore, standoff distance, current and pressure of the atomizing gas were varied to investigate the influence of these process parameters on the electrical resistivity of Zn coatings using a full factorial experiment design with center point. It can be observed that the electrical resistivity of the Zn coatings increases with decreasing current and increasing standoff distance and pressure.

  1. Metal coatings on long-period fiber gratings and the implementation of an associated sensing model

    Science.gov (United States)

    Li, Yulong; Jiang, Jianfeng; Wang, Feifan; Fu, Yanshu; Zhang, Hua

    2017-05-01

    A mathematical model for analyzing the temperature sensing properties of a metal-coated long-period fiber grating (LPFG) was presented. The influences of metal coatings on the temperature sensing properties of LPFGs were simulated and experimentally investigated. The effects of various material parameters were estimated using the single variable method of the Matlab 7.0 software. The simulation results showed that temperature sensitivity increased with an increasing elastic modulus, Poisson's ratio, and thermal expansion coefficient of the coating metal. Both the experimental and simulated results showed that the thickness of the metal coating had a significant impact on the associated temperature sensing properties. The calculated temperature sensitivities of the LPFGs with Ni-coating thicknesses of 6.5, 5.2, and 7.2 μm were 57.27, 60.91, and 66.55 pm/°C, respectively; and with Cu-coating thicknesses of 3.8, 4.9, and 5.4 μm, the calculated temperature sensitivities were 58.17, 59.58, and 61.18 pm/°C, respectively. Compared to the experimental results, the relative errors in the simulation were less than 9.75%, indicating the feasibility of the new temperature sensing model.

  2. A Fundamental Metric for Metal Recycling Applied to Coated Magnesium

    NARCIS (Netherlands)

    Meskers, C.E.M.; Reuter, M.A.; Boin, U.; Kvithyld, A.

    2008-01-01

    A fundamental metric for the assessment of the recyclability and, hence, the sustainability of coated magnesium scrap is presented; this metric combines kinetics and thermodynamics. The recycling process, consisting of thermal decoating and remelting, was studied by thermogravimetry and differential

  3. Copper Metallic Substrates for High Temperature Superconducting Coated Conductors

    National Research Council Canada - National Science Library

    Yust, Nicholas A; Nekkanti, Rama; Brunke, Lyle B; Srinivasan, Raghavan; Barnes, Paul N

    2006-01-01

    ...) coated conductor applications. A comparison is made between Cu substrates fabricated by reverse cold rolling followed by recrystallization, from stock materials that were obtained in the form of extruded rod and rolled plate...

  4. Theoretical analysis and coating thickness determination of a dual layer metal coated FBG sensor for sensitivity enhancement at cryogenic temperatures

    Science.gov (United States)

    Ramalingam, Rajinikumar; Atrey, M. D.

    2017-12-01

    Use of Fiber Bragg Grating (FBG) sensor is very appealing for sensing low temperature and strain in superconducting magnets because of their miniature size and the possibility of accommodating many sensors in a single fiber. The main drawback is their low intrinsic thermal sensitivity at low temperatures below 120 K. Approaching cryogenic temperatures, temperature changes lower than a few degrees Kelvin cannot be resolved, since they do not cause an appreciable shift of the wavelength diffracted by a bare FBG sensor. To improve the thermal sensitivity and thermal inertia below 77 K, the Bare FBG (BFBG) sensor can be coated with high thermal expansion coefficient materials. In this work, different metal were considered for coating the FBG sensor. For theoretical investigation, a double layered circular thick wall tube model has been considered to study the effect on sensitivity due to the mechanical properties like Young’s modulus, Thermal expansion coefficient, Poisson’s ratio of selected materials at a various cryogenic temperatures. The primary and the secondary coating thickness for a dual layer metal coated FBG sensor have been determined from the above study. The sensor was then fabricated and tested at cryogenic temperature range from 4-300 K. The cryogenic temperature characteristics of the tested sensors are reported.

  5. Ionic Transport Through Metal-Rich Organic Coatings

    Science.gov (United States)

    2016-08-19

    pH and chloride ion concentration levels over time. As the corrosion protection of the coating decreases, chloride ion concentration will increase...Hitorff cell, the nine independent formulations from the orthogonal matrix were tested for pH and chloride ion concentration levels over time. As the...corrosion protection of the coating decreases, chloride ion concentration will increase. Preliminary tests indicate that the effects of MPV percent

  6. Coated metal hydrides for stationary energy storage applications

    OpenAIRE

    Mistry, Priyen C.

    2016-01-01

    This thesis explores suitable materials for energy stores for stationary applications, specifically a prototype hydrogen store, domestic thermal store operating between 25-100 C and a moderate thermal store for a concentrated solar power (CSP) plant operating at 400 C. The approach incorporated a unique coating technique to deliver prototype hydrogen and thermal storage media, where the coating could offer commercial advantages, for example, in the form of hydride activation and enhanced kine...

  7. Osseoconductive and Corrosion-Inhibiting Plasma-Sprayed Calcium Phosphate Coatings for Metallic Medical Implants

    Directory of Open Access Journals (Sweden)

    Robert B. Heimann

    2017-11-01

    Full Text Available During the last several decades, research into bioceramic coatings for medical implants has emerged as a hot topic among materials scientists and clinical practitioners alike. In particular, today, calcium phosphate-based bioceramic materials are ubiquitously used in clinical applications to coat the stems of metallic endoprosthetic hips as well as the surfaces of dental root implants. Such implants frequently consist of titanium alloys, CoCrMo alloy, or austenitic surgical stainless steels, and aim at replacing lost body parts or restoring functions to diseased or damaged tissues of the human body. In addition, besides such inherently corrosion-resistant metals, increasingly, biodegradable metals such as magnesium alloys are being researched for osseosynthetic devices and coronary stents both of which are intended to remain in the human body for only a short time. Biocompatible coatings provide not only vital biological functions by supporting osseoconductivity but may serve also to protect the metallic parts of implants from corrosion in the aggressive metabolic environment. Moreover, the essential properties of hydroxylapatite-based bioceramic coatings including their in vitro alteration in contact with simulated body fluids will be addressed in this current review paper. In addition, a paradigmatic shift is suggested towards the development of transition metal-substituted calcium hexa-orthophosphates with the NaSiCON (Na superionic conductor structure to be used for implant coatings with superior degradation resistance in the corrosive body environment and with pronounced ionic conductivity that might be utilized in novel devices for electrical bone growth stimulation.

  8. Nondestructive inspection of plasma-sprayed metallic coatings for coal conversion equipment

    Energy Technology Data Exchange (ETDEWEB)

    Scott, G.W.; Snyder, S.D.; Simpson, W.A. Jr.

    1979-12-01

    This report describes the results of a project to develop nondestructive inspection techniques for metallic wear- and process-resistant coatings used in coal system components. Physical properties, especially porosity, and the nominal 0.25 mm (0.010 in.) thickness complicate the inspection of these coatings. The class of coatings selected for laboratory evaluation were CoCrAlY (cobalt-chromium-aluminum-yttrium) types; the specific material used was a Union Carbide spray powder, UCAR LCO-7, which is Co-22.8% Cr-12.9% Al-0.6% Y, sprayed onto alloy 800 substrates. The desired inspection techniques were to: (1) detect cracks or holes in the coating; (2) measure the coating thickness from the coated side; and (3) detect lamellar flaws or separations within the coating layer or between the coating and the substrate. Surface methods (such as liquid penetrant), eddy currents, and radiography were investigated for crack and hole detection; eddy currents, x-ray fluorescence, and ultrasonics were investigated for thickness measurement; and ultrasonics and infrared thermography were investigated for lamellar flaw detection. In general, we determined that significant development effort was required to adapt even the more common and highly developed techniques to the coating inspection problems. Significant progress was made in a number of the investigations undertaken, but financial restraints prevented completion of the planned work.

  9. Electrodes synthesized from carbon nanostructures coated with a smooth and conformal metal adlayer

    Science.gov (United States)

    Adzic, Radoslav; Harris, Alexander

    2014-04-15

    High-surface-area carbon nanostructures coated with a smooth and conformal submonolayer-to-multilayer thin metal films and their method of manufacture are described. The preferred manufacturing process involves the initial oxidation of the carbon nanostructures followed by a surface preparation process involving immersion in a solution with the desired pH to create negative surface dipoles. The nanostructures are subsequently immersed in an alkaline solution containing a suitable quantity of non-noble metal ions which adsorb at surface reaction sites. The metal ions are then reduced via chemical or electrical means. The nanostructures are exposed to a solution containing a salt of one or more noble metals which replace adsorbed non-noble surface metal atoms by galvanic displacement. The process can be controlled and repeated to obtain a desired film coverage. The resulting coated nanostructures may be used, for example, as high-performance electrodes in supercapacitors, batteries, or other electric storage devices.

  10. High level waste containing granules coated and embedded in metal as an alternative to HLW glasses

    International Nuclear Information System (INIS)

    Neumann, W.

    1980-01-01

    Simulated high level waste containing granules were overcoated with pyrocarbon or nickel respectively. The coatings were performed by the use of chemical vapour deposition in a fluidized bed. The coated granules were embedded in an aluminium-silicon-alloy to improve the dissipation of radiation induced heat. The metal-granules-composites obtained were of improved product stability related to the high level waste containing glasses. (orig.) [de

  11. Investigation of antimicrobial activity and morphological properties of metal coated textile surfaces

    International Nuclear Information System (INIS)

    Aslan, Necdet; Sen, Tuba; Senturk, Kenan; Corukhlu, Turgay; Varturk, Ipek; Seker, S.; Shahidi, S.; Korachi, May; Dobrovolskiy, A.M.; Tsiolko, V.V.; Matsevich, S.V.; Keskin, S.S.

    2014-01-01

    The results of investigation antimicrobial and surface properties of the textiles metal coated by means of magnetron or the cleaning-deposition system, which is based on sequentially arranged DC anode layer accelerator and hollow cathode, are presented. The antimicrobial properties against bacteria E. coli and S. aureus of cotton and polyester/cotton textiles coated by Cu, Ti and Ag with the use of two different systems were examined and compared.

  12. Cube-textured metal substrates for reel-to-reel processing of coated conductors

    DEFF Research Database (Denmark)

    Wulff, Anders Christian

    This thesis presents the results of a study aimed at investigating important fabrication aspects of reel-to-reel processing of metal substrates for coated conductors and identifying a new substrate candidate material with improved magnetic properties. The eect of mechanical polishing on surface r...... texture and the fraction of low angle grain boundaries. Finally, a Ni-5Cu-5W substrate may be a good candidate material as a substrate in future coated conductors....

  13. Metal coated functionalized single-walled carbon nanotubes for composite applications

    Science.gov (United States)

    Zeng, Qiang

    This study is considered as a method for producing multifunctional composite materials by using metals coated Single-walled Carbon Nanotubes (SWCNTs). In this research, various metals (Ni, Cu, Ag) were successfully deposited onto the surface of SWCNTs. It has been found that homogenous dispersion and dense nucleation sites are the necessary conditions to form uniform coatings on SWCNTs. Functionalization has been applied to achieve considerable improvement in the dispersion of purified SWCNTs and creates more nucleation sites for subsequent metal deposition. A three-step electroless plating approach was used and the coating mechanism is described in the paper. The samples were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Raman spectroscopy, fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). Bulk copper/aluminum-SWNT composites were processed by powder metallurgy with wet mixing techniques. Coated SWCNTs were well dispersed in the metal matrix. Cold pressing followed by sintering was applied to control porosity. The relationships between hardness and SWCNTs addition were discussed. Ni-SWCNTs composite coatings were prepared by electro-composite deposition. SWCNTs were suspended in a Ni deposition electrolyte and deposited together with nickel during electrodeposition. SWCNTs concentrations in the coatings were found to be related to the SWCNTs concentration in the solution, current density and agitation rate. The microstructure of the coatings has been examined by electron microscopy. Ni coated SWCNTs were also incorporated into the high temperature Bismaleimide (BMI)/graphite composite to improve Electromagnetic Interference (EMI) shielding and surface conductivity. The vacuum assisted resin transfer molding (VARTM) was used to process these composites. Surface and volume resistivity and EMI shielding effectiveness of the composites

  14. Cold spray of metal-polymer composite coatings onto carbon fiber-reinforced polymer (CFRP)

    OpenAIRE

    Bortolussi, Vincent; Borit, François; Chesnaud, Anthony; Jeandin, Michel; Faessel, Matthieu; Figliuzzi, Bruno; Willot, François; Roche, K.; Surdon, G.

    2016-01-01

    International audience; The growing use of Polymer-Matrix Composite (PMC) materials within transport industry raises new security concerns, especially those due to lightning. To protect these electrically insulating materials, conductive coatings can be applied. Due to the high level of required properties, cold spray is believed to be an effective way to achieve these coatings. Recent studies showed that obstacles remained to be overcome when cold spraying metallic particles onto Carbon Fibe...

  15. A shape-recovery polymer coating for the corrosion protection of metallic surfaces.

    Science.gov (United States)

    Lutz, Alexander; van den Berg, Otto; Van Damme, Jonas; Verheyen, Karen; Bauters, Erwin; De Graeve, Iris; Du Prez, Filip E; Terryn, Herman

    2015-01-14

    Self-healing polymer coatings are a type of smart material aimed for advanced corrosion protection of metals. This paper presents the synthesis and characterization of two new UV-cure self-healing coatings based on acrylated polycaprolactone polyurethanes. On a macroscopic scale, the cured films all show outstanding mechanical properties, combining relatively high Young's modulus of up to 270 MPa with a strain at break above 350%. After thermal activation the strained films recover up to 97% of their original length. Optical and electron microscopy reveals the self-healing properties of these coatings on hot dip galvanized steel with scratches and microindentations. The temperature-induced closing of such defects restores the corrosion protection and barrier properties of the coating as shown by electrochemical impedance spectroscopy and scanning vibrating electrode technique. Therefore, such coatings are a complementary option for encapsulation-based autonomous corrosion protection systems.

  16. Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

    Science.gov (United States)

    Schramm, Harry F. (Inventor); Defalco, Francis G. (Inventor); Starks, Lloyd L., Sr. (Inventor)

    2013-01-01

    A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

  17. Sensing of heavy metal ions by intrinsic TMV coat protein fluorescence

    Science.gov (United States)

    Bayram, Serene S.; Green, Philippe; Blum, Amy Szuchmacher

    2018-04-01

    We propose the use of a cysteine mutant of TMV coat protein as a signal transducer for the selective sensing and quantification of the heavy metal ions, Cd2+, Pb2+, Zn2+ and Ni2+ based on intrinsic tryptophan quenching. TMV coat protein is inexpensive, can be mass-produced since it is expressed and extracted from E-coli. It also displays several different functional groups, enabling a wide repertoire of bioconjugation chemistries; thus it can be easily integrated into functional devices. In addition, TMV-ion interactions have been widely reported and utilized for metallization to generate organic-inorganic hybrid composite novel materials. Building on these previous observations, we herein determine, for the first time, the TMV-ion binding constants assuming the static fluorescence quenching model. We also show that by comparing TMV-ion interactions between native and denatured coat protein, we can distinguish between chemically similar heavy metal ions such as cadmium and zinc ions.

  18. Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal

    Directory of Open Access Journals (Sweden)

    A. Nikitin

    2017-01-01

    Full Text Available Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT® in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals.

  19. Thin Glass Coatings for the Corrosion Protection of Metals

    DEFF Research Database (Denmark)

    Lampert, Felix

    This dissertation presents the research work aimed at developing functional submicrometer thick SiOx barrier coatings for the corrosion protection of stainless steel substrates in chloride containing media, which may enable the use of stainless steels as plate material for marine heat exchangers......, and thus lower the component cost with respect to incumbent materials such as titanium alloys. The technology is of particular interest for the application on heat exchanger plates and components, since the thin coating films are expected to serve as efficient ionic barrier coatings, which prevent issues...... with localized corrosion and do not impact the heat transfer or the component performance. The herein presented approach focuses primarily on the formation of SiOx-like thin films from Hydrogen Silsesquioxane (HSQ) –based “spin-on-glass” (SOG) precursor. The technology is well known for the deposition...

  20. Surface Functionalization of Metal-Organic Framework Crystals with Catechol Coatings for Enhanced Moisture Tolerance.

    Science.gov (United States)

    Castells-Gil, Javier; Novio, Fernando; Padial, Natalia M; Tatay, Sergio; Ruíz-Molina, Daniel; Martí-Gastaldo, Carlos

    2017-12-27

    Robust catechol coatings for enhanced moisture tolerance were produced in one step by direct reaction of Hong Kong University of Science and Technology (HKUST) with synthetic catechols. We ascribe the rapid formation of homogeneous coatings around the metal-organic framework particles to the biomimetic catalytic activity of Cu(II) dimers in the external surface of the crystals. Use of fluorinated catechols results in hydrophobic, permeable coatings that protect HKUST from water degradation while retaining close to 100% of its original sorption capacity.

  1. Coating compositions and method for the treatment of metal surfaces

    International Nuclear Information System (INIS)

    Das, N.; Stastny, P.M.

    1984-01-01

    An aqeuous acidic composition provides improved coating for aluminum. The composition comprises from about 10 to about 150 ppm zirconium, from about 20 to about 250 ppm fluoride, from 30 to about 125 ppm tannin, from about about 15 to about 100 ppm phosphate and from about 5 to about 50 ppm zinc, said coating solution having a tannin to phosphate ratio in the range of at least about 1:1 to about 2:1 and a pH in the range of about 2.3 to about 2.95

  2. Electro-chemical deposition of nano hydroxyapatite-zinc coating on titanium metal substrate.

    Science.gov (United States)

    El-Wassefy, N A; Reicha, F M; Aref, N S

    2017-08-13

    Titanium is an inert metal that does not induce osteogenesis and has no antibacterial properties; it is proposed that hydroxyapatite coating can enhance its bioactivity, while zinc can contribute to antibacterial properties and improve osseointegration. A nano-sized hydroxyapatite-zinc coating was deposited on commercially pure titanium using an electro-chemical process, in order to increase its surface roughness and enhance adhesion properties. The hydroxyapatite-zinc coating was attained using an electro-chemical deposition in a solution composed of a naturally derived calcium carbonate, di-ammonium hydrogen phosphate, with a pure zinc metal as the anode and titanium as the cathode. The applied voltage was -2.5 for 2 h at a temperature of 85 °C. The resultant coating was characterized for its surface morphology and chemical composition using a scanning electron microscope (SEM), energy dispersive x-ray spectroscope (EDS), and Fourier transform infrared (FT-IR) spectrometer. The coated specimens were also evaluated for their surface roughness and adhesion quality. Hydroxyapatite-zinc coating had shown rosette-shaped, homogenous structure with nano-size distribution, as confirmed by SEM analysis. FT-IR and EDS proved that coatings are composed of hydroxyapatite (HA) and zinc. The surface roughness assessment revealed that the coating procedure had significantly increased average roughness (Ra) than the control, while the adhesive tape test demonstrated a high-quality adhesive coat with no laceration on tape removal. The developed in vitro electro-chemical method can be employed for the deposition of an even thickness of nano HA-Zn adhered coatings on titanium substrate and increases its surface roughness significantly.

  3. Phosphate chemical conversion coatings on metallic substrates for biomedical application: a review.

    Science.gov (United States)

    Liu, Bing; Zhang, Xian; Xiao, Gui-yong; Lu, Yu-peng

    2015-02-01

    Phosphate chemical conversion (PCC) technology has been investigated for improving the surface performance of metallic implants in the biomedical field over the last decade. The metallic materials, such as magnesium and its alloys, titanium, pure iron and stainless steel are widely used as orthopedic devices for immobilization of bone fractures in clinic. They were previously studied as metal substrates for PCC coating aiming to modify their biocompatibility and osteoconductivity. Zinc, calcium and zinc-calcium PCC coatings are frequently utilized considering their nature and the end-use. Although PCC coating has been confirmed to potentially improve the bio-performance of metallic implants in vitro and in vivo by many researchers, there are no unified standards or regulations to give quantitative appraisal of its quality and property. As such, an overview of several main phosphate phases together with their properties and behaviors in vitro and in vivo was conducted. The mechanism of phosphating was also briefly discussed. Critical qualities of PCC coating used for biomedical application including corrosion resistance, wettability and bonding strength were analyzed separately. Biological response including in vitro cell investigations and in vivo tissue response were discussed in terms of the cytocompatibility and bioactivity of PCC coating. Further investigations are proposed to develop appropriate performance evaluation measurements by combining conventional technologies and biomedical procedures. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Tribological study of novel metal-doped carbon-based coatings with enhanced thermal stability

    Science.gov (United States)

    Mandal, Paranjayee

    Low friction and high temperature wear resistant PVD coatings are in high demand for use on engine components, which operate in extreme environment. Diamond-like-carbon (DLC) coatings are extensively used for this purpose due to their excellent tribological properties. However, DLC degrades at high temperature and pressure conditions leading to significant increase in friction and wear rate even in the presence of lubricant. To withstand high working temperature and simultaneously maintain improved tribological properties in lubricated condition at ambient and at high temperature, both the transitional metals Mo and W are simultaneously introduced in a carbon-based coating (Mo-W-C) for the first time utilising the benefits of smart material combination and High Power Impulse Magnetron Sputtering (HIPIMS).This research includes development of Mo-W-C coating and investigation of thermal stability and tribological properties at ambient and high temperatures. The as-deposited Mo-W-C coating contains nanocrystalline almost X-ray amorphous structure and show dense microstructure, good adhesion with substrate (Lc -80 N) and high hardness (-17 GPa). During boundary lubricated sliding (commercially available engine oil without friction modifier used as lubricant) at ambient temperature, Mo-W-C coating outperforms commercially available state-of-the-art DLC coatings by providing significantly low friction (u- 0.03 - 0.05) and excellent wear resistance (no measurable wear). When lubricated sliding tests are carried out at 200°C, Mo-W-C coating provides low friction similar to ambient temperature, whereas degradation of DLC coating properties fails to maintain low friction coefficient.A range of surface analyses techniques reveal "in-situ" formation of solid lubricants (WS2 and M0S2) at the tribo-contacts due to tribochemically reactive wear mechanism at ambient and high temperature. Mo-W-C coating reacts with EP additives present in the engine oil during sliding to form WS2

  5. From Coating to Dopant: How the Transition Metal Composition Affects Alumina Coatings on Ni-Rich Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Binghong [Chemical; Key, Baris [Chemical; Lapidus, Saul H. [Chemical; Garcia, Juan C. [Chemical; Iddir, Hakim [Chemical; Vaughey, John T. [Chemical; Dogan, Fulya [Chemical

    2017-11-14

    Surface alumina coatings have been shown to be an effective way to improve the stability and cyclability of cathode materials. However, a detailed understanding of the relationship between the surface coatings and the bulk layered oxides is needed to better define the critical cathode–electrolyte interface. In this paper, we systematically studied the effect of the composition of Ni-rich LiNixMnyCo1–x–yO2 (NMC) on the surface alumina coatings. Changing cathode composition from LiNi0.5Mn0.3Co0.2O2 (NMC532) to LiNi0.6Mn0.2Co0.2O2 (NMC622) and LiNi0.8Mn0.1Co0.1O2 (NMC811) was found to facilitate the diffusion of surface alumina into the bulk after high-temperature annealing. By use of a variety of spectroscopic techniques, Al was seen to have a high bulk compatibility with higher Ni/Co content, and low bulk compatibility was associated with Mn in the transition metal layer. It was also noted that the cathode composition affected the observed morphology and surface chemistry of the coated material, which has an effect on electrochemical cycling. The presence of a high surface Li concentration and strong alumina diffusion into the bulk led to a smoother surface coating on NMC811 with no excess alumina aggregated on the surface. Structural characterization of pristine NMC particles also suggests surface Co segregation, which may act to mediate the diffusion of the Al from the surface to the bulk. The diffusion of Al into the bulk was found to be detrimental to the protection function of surface coatings leading to poor overall cyclability, indicating the importance of compatibility between surface coatings and bulk oxides on the electrochemical performance of coated cathode materials. These results are important in developing a better coating method for synthesis of next-generation cathode materials for lithium-ion batteries.

  6. Zr-based conversion coatings for multi-metal substrates

    NARCIS (Netherlands)

    Cerezo Palacios, J.M.

    2015-01-01

    In this PhD work, a new surface treatment based on the application of Zr-based conversion coatings by immersion in a Cu containing Zr-based conversion solution was investigated as a replacement of the traditional phosphating process for the automotive industry. Nowadays most of the cars are made of

  7. Metal-coated magnetic nanoparticles for surface enhanced Raman ...

    Indian Academy of Sciences (India)

    We report the optimization and usage of surfactantless, water dispersible Ag and Au-coated γ–Fe2O3 nanoparticles for applications in surface-enhanced .... After the solvent evaporated, 2 μL of analyte of ∼1 μM concentration was ..... dry soil, and comprised of smooth, distinct, rectangular and square shaped islands, whose ...

  8. Metal nanoparticle doped coloured coatings on glasses and plastics ...

    Indian Academy of Sciences (India)

    Pt) nanoparticles in SiO2, Au in mixed SiO2–TiO2 and SiO2–ZrO2, Au and Ag nanoparticles in inorganic–organic hybrid film matrices etc. This investigation leads to the development of tailor-made coloured coatings by tuning the surface ...

  9. Hybrid plasmonic waveguides formed by metal coating of dielectric ridges

    DEFF Research Database (Denmark)

    Zenin, Volodymyr; Choudhury, Sajid; Saha, Soham

    2017-01-01

    Bound hybrid plasmon-polariton modes supported by waveguides, which are formed by gold coating of ridges etched into a silica substrate, are analyzed using numerical simulations and investigated experimentally using near-field microscopy at telecom wavelengths (1425-1625 nm). Drastic modifications...

  10. Recycling light metals : Optimal thermal de-coating

    NARCIS (Netherlands)

    Kvithyld, A.; Meskers, C.E.M.; Gaal, S.; Reuter, M.

    2008-01-01

    Thermal de-coating of painted and lacquered scrap is one of the new innovations developed for aluminum recycling. If implemented in all recycling and optimized as suggested in this article, recovery would be improved with considerable economic impact. Generally, contaminated scrap is difficult to

  11. 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)

  12. Carbon nanostructures and graphite-coated metal nanostructures ...

    Indian Academy of Sciences (India)

    Under certain conditions, pyrolysis of ruthenocene gives rise to graphite coated ruthenium nanoparticles as well as worm-like carbon structures. Pyrolysis of mixtures of ruthenocene and ferrocene gives rise to nanoparticles or nanorods of FeRu alloys, the composition depending upon the composition of the original mixture.

  13. Bacterial adhesion on amorphous and crystalline metal oxide coatings

    Energy Technology Data Exchange (ETDEWEB)

    Almaguer-Flores, Argelia [Facultad de Odontología, División de Estudios de Posgrado e Investigación, Universidad Nacional Autónoma de México, Circuito exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico); Silva-Bermudez, Phaedra, E-mail: suriel21@yahoo.com [Unidad de Ingeniería de Tejidos, Terapia Celular y Medicina Regenerativa, Instituto Nacional de Rehabilitación, Calzada México-Xochimilco No. 289, Col. Arenal de Guadalupe, 14389 México D.F. (Mexico); Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico); Galicia, Rey; Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico)

    2015-12-01

    Several studies have demonstrated the influence of surface properties (surface energy, composition and topography) of biocompatible materials on the adhesion of cells/bacteria on solid substrates; however, few have provided information about the effect of the atomic arrangement or crystallinity. Using magnetron sputtering deposition, we produced amorphous and crystalline TiO{sub 2} and ZrO{sub 2} coatings with controlled micro and nanoscale morphology. The effect of the structure on the physical–chemical surface properties was carefully analyzed. Then, we studied how these parameters affect the adhesion of Escherichia coli and Staphylococcus aureus. Our findings demonstrated that the nano-topography and the surface energy were significantly influenced by the coating structure. Bacterial adhesion at micro-rough (2.6 μm) surfaces was independent of the surface composition and structure, contrary to the observation in sub-micron (0.5 μm) rough surfaces, where the crystalline oxides (TiO{sub 2} > ZrO{sub 2}) surfaces exhibited higher numbers of attached bacteria. Particularly, crystalline TiO{sub 2}, which presented a predominant acidic nature, was more attractive for the adhesion of the negatively charged bacteria. The information provided by this study, where surface modifications are introduced by means of the deposition of amorphous or crystalline oxide coatings, offers a route for the rational design of implant surfaces to control or inhibit bacterial adhesion. - Highlights: • Amorphous (a) and crystalline (c) TiO{sub 2} and ZrO{sub 2} coatings were deposited. • The atomic ordering influences the coatings surface charge and nano-topography. • The atomic ordering modifies the bacterial adhesion for the same surface chemistry. • S. aureus adhesion was lower on a-TiO{sub 2} and a-ZrO{sub 2} than on their c-oxide counterpart. • E. coli adhesion on a-TiO{sub 2} was lower than on the c-TiO{sub 2}.

  14. Novel biopolymer-coated hydroxyapatite foams for removing heavy-metals from polluted water

    International Nuclear Information System (INIS)

    Vila, M.; Sanchez-Salcedo, S.; Cicuendez, M.; Izquierdo-Barba, I.; Vallet-Regi, Maria

    2011-01-01

    Highlights: → 3D-macroporous biopolymer-coated hydroxyapatite (HA) foams as potential devices for the treatment of heavy metal ions. → HA stable foams coated with biopolymers. → Feasible advance in development of new, easy to handle and low cost water purifying methods. - Abstract: 3D-macroporous biopolymer-coated hydroxyapatite (HA) foams have been developed as potential devices for the treatment of lead, cadmium and copper contamination of consumable waters. These foams have exhibited a fast and effective ion metal immobilization into the HA structure after an in vitro treatment mimicking a serious water contamination case. To improve HA foam stability at contaminated aqueous solutions pH, as well as its handling and shape integrity the 3D-macroporous foams have been coated with biopolymers polycaprolactone (PCL) and gelatine cross-linked with glutaraldehyde (G/Glu). Metal ion immobilization tests have shown higher and fast heavy metals captured as function of hydrophilicity rate of biopolymer used. After an in vitro treatment, foam morphology integrity is guaranteed and the uptake of heavy metal ions rises up to 405 μmol/g in the case of Pb 2+ , 378 μmol/g of Cu 2+ and 316 μmol/g of Cd 2+ . These novel materials promise a feasible advance in development of new, easy to handle and low cost water purifying methods.

  15. Fundamental mechanical and microstructural observations in metallic glass coating production

    NARCIS (Netherlands)

    Matthews, D.T.A.; Ocelik, V.; de Hosson, J.T.M.; DeHosson, JTM; Brebbia, CA; Nishida, SI

    2005-01-01

    The production of a wide range of metallic Glass Forming Alloys (GFA) has been investigated by several processing routes including simple arc-casting and melt-spinning to form Bulk Metallic Glasses (BMG). The concepts surrounding such alloys have been directed towards the production of thick (> 300

  16. Thermal Shock Resistance of Stabilized Zirconia/Metal Coat on Polymer Matrix Composites by Thermal Spraying Process

    Science.gov (United States)

    Zhu, Ling; Huang, Wenzhi; Cheng, Haifeng; Cao, Xueqiang

    2014-12-01

    Stabilized zirconia/metal coating systems were deposited on the polymer matrix composites by a combined thermal spray process. Effects of the thicknesses of metal layers and ceramic layer on thermal shock resistance of the coating systems were investigated. According to the results of thermal shock lifetime, the coating system consisting of 20 μm Zn and 125 μm 8YSZ exhibited the best thermal shock resistance. Based on microstructure evolution, failure modes and failure mechanism of the coating systems were proposed. The main failure modes were the formation of vertical cracks and delamination in the outlayer of substrate, and the appearance of coating spallation. The residual stress, thermal stress and oxidation of substrate near the substrate/metal layer interface were responsible for coating failure, while the oxidation of substrate near the substrate/coating interface was the dominant one.

  17. Morphology Analysis and Process Research on Novel Metal Fused-coating Additive Manufacturing

    Science.gov (United States)

    Wang, Xin; Wei, Zheng ying; Du, Jun; Ren, Chuan qi; Zhang, Shan; Zhang, Zhitong; Bai, Hao

    2017-12-01

    Existing metal additive manufacturing equipment has high capital costs and slow throughput printing. In this paper, a new metal fused-coating additive manufacturing (MFCAM) was proposed. Experiments of single-track formation were conducted using MFCAM to validate the feasibility. The low melting alloy was selected as the forming material. Then, the effect of process parameters such as the flow rate, deposition velocity and initial distance on the forming morphology. There is a strong coupling effect between the single track forming morphology. Through the analysis of influencing factors to improve the forming quality of specimens. The experimental results show that the twice as forming efficiency as the metal droplet deposition. Additionally, the forming morphology and quality were analyzed by confocal laser scanning microscope and X-ray. The results show that the metal fused-coating process can achieve good surface morphology and without internal tissue defect.

  18. Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters

    CERN Document Server

    Dash, Monika

    2013-01-01

    Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

  19. The phospholipid vesicles coating on metal chelated inorganic surfaces

    International Nuclear Information System (INIS)

    Chang, Jeong Ho; Cho, Min Ae; Son, Hong Ha; Lee, Cheon Koo; Kim, Kyung Ja

    2007-01-01

    This work showed the formation of phospholipid vesicle coating on inorganic sericite surface with characterization by combining electron microscopy of FE-SEM, TEM, AFM, and qualitatively evaluated the coated phospholipid vesicle by XPS as a function of etching time. The possibility of phospholipid vesicle mobility on the surface was restrained by the chelation effect of magnesium cation. The stabilization properties of phospholipid vesicles on sericite surface were demonstrated by the various concentration of magnesium cation. The presence of magnesium was found to have a much more pronounced influence on the lipid deposition process. The Mg cation plays an important role for attaching the phospholipids with optimum concentration of 7 mM. Totally, the phospholipid vesicles coating on inorganic powder could be useful for bio-related fields such as cosmetics and drug delivery system as the key functional compounds. We hope this basic result lead to a general and simple approach to prepare a wide a range of controlled releasing materials including an encapsulation with cosmetics or drugs

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  1. In situ ceramic layer growth on coated fuel particles dispersed in a zirconium metal matrix

    Science.gov (United States)

    Terrani, K. A.; Silva, C. M.; Kiggans, J. O.; Cai, Z.; Shin, D.; Snead, L. L.

    2013-06-01

    The extent and nature of the chemical interaction between the outermost coating layer of coated fuel particles embedded in zirconium metal during fabrication of metal matrix microencapsulated fuels were examined. Various particles with outermost coating layers of pyrocarbon, SiC, and ZrC have been investigated in this study. ZrC-Zr interaction was the least substantial, while the PyC-Zr reaction can be exploited to produce a ZrC layer at the interface in an in situ manner. The thickness of the ZrC layer in the latter case can be controlled by adjusting the time and temperature during processing. The kinetics of ZrC layer growth is significantly faster from what is predicted using literature carbon diffusivity data in ZrC. SiC-Zr interaction is more complex and results in formation of various chemical phases in a layered aggregate morphology at the interface.

  2. Novel ceramic coatings for containment of uranium and reactive molten metals

    International Nuclear Information System (INIS)

    Sreekumar, K.P.; Satpute, R.U.; Ramanathan, S.; Thiyagarajan, T.K.; Padmanabhan, P.V.A.; Kutty, T.R.G.

    2005-01-01

    Plasma sprayed aluminium oxide coatings, which are currently used for casting uranium metal are, however, not suitable for long duration handling of molten uranium and is also unstable under reducing conditions. Yttrium oxide and rare earth phosphates are suggested as promising materials for prevention of high temperature corrosion by molten metals. The present paper reports research efforts directed towards development of plasma sprayed coatings of yttria and lanthanum phosphate. Thermal spray grade powders of yttrium oxide and lanthanum phosphate, synthesized using locally available raw materials have been used as feedstock powders for plasma spray deposition. The coatings have been deposited using the indigenously developed 40 kW atmospheric plasma spray system and have been characterized. Results of preliminary experiments on compatibility of yttria and lanthanum phosphate with molten uranium are quite encouraging. (author)

  3. Preparation of Al-based metal matrix composites reinforced by Cu coated SiC particles

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hailong; Zhang Rui; Xu Hongliang; Lu Hongxia; Guan Shaokang [Coll. of Materials Engineering, Zhengzhou Univ., HEN (China)

    2005-07-01

    In order to improve the interfacial behavior between SiC and Al, a surface layer of Cu was coated on SiC particles. The influence of pH value on the coating process was analyzed. A powder metallurgy method was used to prepare the Al-based metal matrix composites (MMCs). SEM, XRD techniques were used to characterize the sintered compacts. It was found that the optimized pH value during the coating process was 1{proportional_to}2. The specimen showed the maximum density when sintered at 750 C. Inter-metallic compound of Al{sub 3.21}Si{sub 0.47} was detected which contributed to the enhancement at the interface between SiC and Al. The hardness of the composites is improved to 90 MPa. (orig.)

  4. Short-Pulse Laser Sintering of Multilayer Hard Metal Coatings: Structure and Wear Behavior

    Science.gov (United States)

    Kharanzhevskiy, Evgeny; Ipatov, Alexey; Nikolaeva, Irina; Zakirova, Raushaniya

    2015-06-01

    This paper reports on the phase composition and properties of multilayer hard metal coatings deposited on steel by a process variant of Selective laser melting (SLM). The process is based on layer-wise short-pulse laser sintering of high-dispersive WC-Co powder on a steel substrate. High temperature in the molten zone and chemical interaction with the substrate explain high level of adhesion strength between the coating and the substrate. The technique allows obtaining both high quality hard-metal multilayer gradient coatings with thickness up to 200 μm, density near to the theoretical density (TD), hardness up to 21 GPa and complex 3D objects by layer-wise powder based process such as SLM.

  5. Co3O4 protective coatings prepared by Pulsed Injection Metal Organic Chemical Vapour Deposition

    DEFF Research Database (Denmark)

    Burriel, M.; Garcia, G.; Santiso, J.

    2005-01-01

    of deposition temperature. Pure Co3O4 spinel structure was found for deposition temperatures ranging from 360 to 540 degreesC. The optimum experimental parameters to prepare dense layers with a high growth rate were determined and used to prepare corrosion protective coatings for Fe-22Cr metallic interconnects...

  6. Effect of metal coating and residual stress on the resonant frequency ...

    Indian Academy of Sciences (India)

    While the metal coating, which acts as electrode, increases the stiffness and the effective mass of the composite structure, the residual stress increases or decreases the net stiffness if it is a tensile or compressive type respectively. In this paper, we investigate both these cases by taking two different structures, namely, the ...

  7. Increasing the solar cell power output by coating with transition metal-oxide nanorods

    International Nuclear Information System (INIS)

    Kuznetsov, I.A.; Greenfield, M.J.; Mehta, Y.U.; Merchan-Merchan, W.; Salkar, G.; Saveliev, A.V.

    2011-01-01

    Highlights: → Nanoparticles enhance solar cell efficiency. → Solar cell power increase by nanorod coating. → Metal-oxide nanorods are prepared in flames. → Molybdenum oxide nanorods effectively scatter light on solar cell surface. → Scattering efficiency depends on coating density. -- Abstract: Photovoltaic cells produce electric current through interactions among photons from an ambient light source and electrons in the semiconductor layer of the cell. However, much of the light incident on the panel is reflected or absorbed without inducing the photovoltaic effect. Transition metal-oxide nanoparticles, an inexpensive product of a process called flame synthesis, can cause scattering of light. Scattering can redirect photon flux, increasing the fraction of light absorbed in the thin active layer of silicon solar cells. This research aims to demonstrate that the application of transition metal-oxide nanorods to the surface of silicon solar panels can enhance the power output of the panels. Several solar panels were coated with a nanoparticle-methanol suspension, and the power outputs of the panels before and after the treatment were compared. The results demonstrate an increase in power output of up to 5% after the treatment. The presence of metal-oxide nanorods on the surface of the coated solar cells is confirmed by electron microscopy.

  8. The role of nanocrystalline binder metallic coating into WC after additive manufacturing

    Science.gov (United States)

    Cavaleiro, A. J.; Fernandes, C. M.; Farinha, A. R.; Gestel, C. V.; Jhabvala, J.; Boillat, E.; Senos, A. M. R.; Vieira, M. T.

    2018-01-01

    Tungsten carbide with microsized particle powders are commonly used embedded in a tough binder metal. The application of these composites is not limited to cutting tools, WC based material has been increasingly used in gaskets and other mechanical parts with complex geometries. Consequently, additive manufacturing processes as Selective Laser Sintering (SLS) might be the solution to overcome some of the manufacturing problems. However, the use of SLS leads to resolve the problems resulting from difference of physical properties between tungsten carbide and the metallic binder, such as laser absorbance and thermal conductivity. In this work, an original approach of powder surface modification was considered to prepare WC-metal composite powders and overcome these constraints, consisting on the sputter-coating of the WC particle surfaces with a nanocrystalline thin film of metallic binder material (stainless steel). The coating improves the thermal behavior and rheology of the WC particles and, at the same time, ensures a binder homogenous distribution. The feasibility of the SLS technology as manufacturing process for WC powder sputter-coated with 13 wt% stainless steel AISI 304L was explored with different laser power and scanning speed parameters. The SLS layers were characterized regarding elemental distribution, phase composition and morphology, and the results are discussed emphasizing the role of the coating on the consolidation process.

  9. Effect of metal coating and residual stress on the resonant frequency ...

    Indian Academy of Sciences (India)

    Effect of metal coating and residual stress on the resonant frequency of MEMS resonators. ASHOK KUMAR PANDEY, K P VENKATESH and RUDRA. PRATAP. ∗. CranesSci MEMS Laboratory, Department of Mechanical Engineering, Indian. Institute of Science, Bangalore 560 012 e-mail: pratap@mecheng.iisc.ernet.in.

  10. Fly ash based geopolymer thin coatings on metal substrates and its thermal evaluation.

    Science.gov (United States)

    Temuujin, Jadambaa; Minjigmaa, Amgalan; Rickard, William; Lee, Melissa; Williams, Iestyn; van Riessen, Arie

    2010-08-15

    Class F fly ash based Na-geopolymer formulations have been applied as fire resistant coatings on steel. The main variables for the coating formulations were Si: Al molar and water: cement weight ratios. We have determined that the adhesive strength of the coatings strongly depend on geopolymer composition. The ease with which geopolymer can be applied onto metal surfaces and the resultant thickness depend on the water content of the formulation. Adhesive strengths of greater than 3.5 MPa have been achieved on mild steel surfaces for compositions with Si:Al of 3.5. Microstructure evolution and thermal properties of the optimised coating formulations show that they have very promising fire resistant characteristics. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Plasma coatings of nitrogen polymers on metal prostheses of the circulatory system

    International Nuclear Information System (INIS)

    Gomez J, L. M.

    2016-01-01

    This work has a study about the synthesis of poly aniline, poly allylamine and poly pyrrole doped with iodine onto metallic surfaces similar to stents for the circulatory system. Ar, water and hydrogen peroxide plasmas were used for eroding, conditioning and synthesizing polymers that potentially reduce some rejection reactions when stents are implanted in the human body. Stents are small metallic meshes that applied inside collapsed arteries or veins enlarge the diameter and restore the blood flow, however the metallic surfaces usually cause rejection reactions that obstruct the veins again. To give solutions to this problem, in this work is studied the synthesis of biocompatible polymer coatings on the stents that resist the blood flow forming a biocompatible interface between metal and blood. The metallic substrates were eroded and chemically prepared with Ar, H 2 O and/or H 2 O 2 glow discharges on which the polymers were synthesized by plasma. The coatings were morphologically characterized by optical, scanning electron and atomic force microscopy, the chemical structure was studied by infrared and photoelectron X-ray spectroscopy. The hydrophilicity was studied measuring the advance static contact angle and the adhesion was evaluated indirectly with scanning electron microscopy after two months submerged in buffered phosphate solutions. The results indicate that the polymers grew following the superficial morphology; that the conditioning with Ar ions erode the substrates and that the conditioning with H 2 O or H 2 O 2 erodes and activates the surface generating oxygen bridges which help in the polymer-metal adhesion. The chemical structure of the polymeric coatings contain crosslinked structures that correspond to links between monomers with the participation of all atoms, states that suggest monomer fragmentation and oxidation and states that indicate oxygen bridges in the polymers. The coatings had contact angles close to 90 degrees where is located the

  12. Electrodeposition of metallic tungsten coating from binary oxide molten salt on low activation steel substrate

    International Nuclear Information System (INIS)

    Liu, Y.H.; Zhang, Y.C.; Jiang, F.; Fu, B.J.; Sun, N.B.

    2013-01-01

    Tungsten is considered a promising plasma facing armor material for future fusion devices. An electrodeposited metallic tungsten coating from Na 2 WO 4 –WO 3 binary oxide molten salt on low activation steel (LAS) substrate was investigated in this paper. Tungsten coatings were deposited under various pulsed currents conditions at 1173 K in atmosphere. Cathodic current density and pulsed duty cycle were investigated for pulsed current electrolysis. The crystal structure and microstructure of tungsten coatings were characterized by X-ray diffractometry, scanning electron microscopy, and energy X-ray dispersive analysis techniques. The results indicated that pulsed current density and duty cycle significantly influence tungsten nucleation and electro-crystallization phenomena. The average grain size of the coating becomes much larger with increasing cathodic current density, which demonstrates that appropriate high cathodic current density can accelerate the growth of grains on the surface of the substrate. The micro-hardness of tungsten coatings increases with the increasing thickness of coatings; the maximum micro-hardness is 482 HV. The prepared tungsten coatings have a smooth surface, a porosity of less than 1%, and an oxygen content of 0.024 wt%

  13. ELECTROCHEMICAL METHODS TO IMPROVE THE WEAR RESISTANCE OF COATING DEPOSITED ON THE METAL SURFACE

    Directory of Open Access Journals (Sweden)

    Yurij Shalapko

    2015-09-01

    Full Text Available It was established that existing methods show low accuracy when assessing the durability of coatings. Furthermore, they don’t allow assessment of the contribution into durability of structural components and fillers for thermodiffusion and polymer-composite coatings, respectively. A method to evaluate durability of thermal diffusion chrome coatings on carbon steel and gray cast irons has been developed - the speed υp of destruction of the structural components of the coating. In addition, the destruction of each structural component is characterized by a constant value of destruction speed υp and potential φ, and their sharp vibrations are in complete destruction of the coating and the beginning of the destruction of the base metal. From the start of the test until the abrupt change in the rate of destruction υp, which is found on the curve υp - τ is the assessment of durability coating t¶ hat is specified with the curve φ - τ. Accuracy of the durability decreases from ± 30 min to ± 2 min. Developed as a way to assess the durability fillers polymer composite coatings, along with the finding that the rate of destruction υp of the time includes total disability coverage t3aƧ and time breakdown cover τn which are fixed on the curve φ - τ.

  14. The erosion performance of cold spray deposited metal matrix composite coatings with subsequent friction stir processing

    Science.gov (United States)

    Peat, Tom; Galloway, Alexander; Toumpis, Athanasios; McNutt, Philip; Iqbal, Naveed

    2017-02-01

    This study forms an initial investigation into the development of SprayStir, an innovative processing technique for generating erosion resistant surface layers on a chosen substrate material. Tungsten carbide - cobalt chromium, chromium carbide - nickel chromium and aluminium oxide coatings were successfully cold spray deposited on AA5083 grade aluminium. In order to improve the deposition efficiency of the cold spray process, coatings were co-deposited with powdered AA5083 using a twin powder feed system that resulted in thick (>300 μm) composite coatings. The deposited coatings were subsequently friction stir processed to embed the particles in the substrate in order to generate a metal matrix composite (MMC) surface layer. The primary aim of this investigation was to examine the erosion performance of the SprayStirred surfaces and demonstrate the benefits of this novel process as a surface engineering technique. Volumetric analysis of the SprayStirred surfaces highlighted a drop of approx. 40% in the level of material loss when compared with the cold spray deposited coating prior to friction stir processing. Micro-hardness testing revealed that in the case of WC-CoCr reinforced coating, the hardness of the SprayStirred material exhibits an increase of approx. 540% over the unaltered substrate and 120% over the as-deposited composite coating. Microstructural examination demonstrated that the increase in the hardness of the MMC aligns with the improved dispersion of reinforcing particles throughout the aluminium matrix.

  15. Bump Bonding Using Metal-Coated Carbon Nanotubes

    Science.gov (United States)

    Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

    2012-01-01

    Bump bonding hybridization techniques use arrays of indium bumps to electrically and mechanically join two chips together. Surface-tension issues limit bump sizes to roughly as wide as they are high. Pitches are limited to 50 microns with bumps only 8-14 microns high on each wafer. A new process uses oriented carbon nanotubes (CNTs) with a metal (indium) in a wicking process using capillary actions to increase the aspect ratio and pitch density of the connections for bump bonding hybridizations. It merges the properties of the CNTs and the metal bumps, providing enhanced material performance parameters. By merging the bumps with narrow and long CNTs oriented in the vertical direction, higher aspect ratios can be obtained if the metal can be made to wick. Possible aspect ratios increase from 1:1 to 20:1 for most applications, and to 100:1 for some applications. Possible pitch density increases of a factor of 10 are possible. Standard capillary theory would not normally allow indium or most other metals to be drawn into the oriented CNTs, because they are non-wetting. However, capillary action can be induced through the ability to fabricate oriented CNT bundles to desired spacings, and the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. This hybridization of two technologies (indium bumps and CNTs) may also provide for some additional benefits such as improved thermal management and possible current density increases.

  16. Reduction Expansion Synthesis of Chromium and Nickel Metal Coatings

    Science.gov (United States)

    2017-06-01

    electrochemical behavior and morphology of trivalent solution- derived chromium coatings,” Revista Mexicana de Ingenieria Quimica, vol. 12, no. 1, pp. 129–141...rays that were diffracted by the loaded sample. This spectrum of peaks was loaded into the PDXL2 software and further processed to characterize the...peak is thought to have been miss identified by the EDS software , as the Fe-L1 peak should be lower than the Fe-Kα peak. If the peak identified as Fe

  17. A study of metallic coatings obtained by electrolysis of molten salts

    International Nuclear Information System (INIS)

    Broc, Michel.

    1978-06-01

    An appropriate technique has been developed for obtaining compact metallic coatings from electrolysis of molten salts. Through the use of this method, it has been possible to produce pure metal deposits which, until now, has been extremely difficult to do. The apparatus used and the main steps of the process such as dehydration of the solvant, degassing of the equipment, and starting of the electrolytic process, are first described. This is followed by a discussion of the deposits of the metals beryllium, uranium, tantalum and tungsten obtained from electrolysis of molten fluorides at temperatures between 600 and 800 0 C. The metal coatings so obtained are homogeneous and show continuity, their thicknesses varying from a few microns to a millimeter or more. They have been studied by measurements. As potential applications of this new technique, one can mention the growth of diffusion barriers and the production of cathodes for thermoionic emission. The method can also be used for electroforming. An intermetallic diffusion between the deposit and the substrate has been observed in some cases. The advantage of the technique of melt electrolysis in obtaining metal coatings of enhanced thicknesses is illustrated by taking the beryllium-nickel system as an example. It is shown that the thickness obtained is proportional to the square root of growth time and is about 6 to 8 times larger than that obtained by conventional techniques [fr

  18. Metal nanoparticle doped coloured coatings on glasses and plastics ...

    Indian Academy of Sciences (India)

    Wintec

    applicable to glass and plastic substrates (Medda et al. 2005a, b; Pal and De 2005; De and De 2006a; Pal and De. 2007a). The manufacturing process involves preparation of sols using suitable metal organic precursors (e.g. alkoxides or functionalized alkoxides also known as in- organic–organic hybrid precursors) and ...

  19. Near-field microwave detection of corrosion precursor pitting under thin dielectric coatings in metallic substrate

    International Nuclear Information System (INIS)

    Hughes, D.; Zoughi, R.; Austin, R.; Wood, N.; Engelbart, R.

    2003-01-01

    Detection of corrosion precursor pitting on metallic surfaces under various coatings and on bare metal is of keen interest in evaluation of aircraft fuselage. Near-field microwave nondestructive testing methods, utilizing open-ended rectangular waveguides and coaxial probes, have been used extensively for detection of surface flaws in metals, both on bare metal and under a dielectric coating. This paper presents the preliminary results of using microwave techniques to detect corrosion precursor pitting under paint and primer, applique and on bare metal. Machined pits of 500 μm diameter were detected using open-ended rectangular waveguides at V-Band under paint and primer and applique, and on bare metal. Using coaxial probes, machined pits with diameters down to 150 μm on bare metal were also detected. Relative pit size and density were shown on a corrosion-pitted sample using open-ended rectangular waveguides at frequencies of 35 GHz to 70 GHz. The use of Boeing's MAUS TM scanning systems provided improved results by alleviating standoff variation and scanning artifact. Typical results of this investigation are also presented

  20. Characteristics of strain transfer and the reflected spectrum of a metal-coated fiber Bragg grating sensor

    Science.gov (United States)

    Kim, Sang-Woo

    2017-09-01

    Previous researchers have simulated strain transfer and spectrum of normal fiber Bragg grating (FBG) sensors with a polymer coating bonded on the structure. They only considered the shear stress in a polymer coating for the simulation. However, for metal-coated FBG sensors, not only shear stress but also axial stress in the metal coating should be reflected into the calculation because its axial stiffness is no longer negligible. Thus, the author investigated the strain transfer and reflected spectra of metal-coated FBG sensors by considering both shear stress and axial stress. The strain transfer analysis involved evaluating the strain profiles along the sensor by plotting an analytical solution, and validating the evaluated profiles with the results obtained by a finite element analysis (FEA). The solution was also verified by the experiments that used aluminum-coated FBG sensors bonded on a carbon fiber reinforced polymer (CFRP) composite specimen. A transfer-matrix (T-matrix) formulation and coupled mode theory were used to simulate the reflected spectra of metal-coated FBG sensors for the evaluated strain profile. In addition, the effect of mechanical and geometric parameters of the sensor was examined. The findings revealed that the strain transfer characteristics and reflected spectra deteriorated with increases in the thickness and Young's modulus of the metal coating due to the consideration of axial stress. It is the opposite results for the normal FBG sensor with a polymer coating. Furthermore, the results also indicated that the decrease in bonding thickness resulted in improved strain transfer and signal characteristics. Moreover, a bonding length of 14 mm was suitable in suppressing an asymmetric shape of the reflected spectrum and in achieving an accurate measurement. The results of the parametric study are expected to contribute to improve the measurement accuracy of metal-coated FBG sensors in actual applications. The analytical methodology can be

  1. Microstructural characterisation of electrodeposited coatings of metal matrix composite with alumina nanoparticles

    International Nuclear Information System (INIS)

    Indyka, P; Beltowska-Lehman, E; Bigos, A

    2012-01-01

    In the present work a nanocrystalline Ni-W metallic matrix was used to fabricate Ni-W/Al 2 O 3 composite coatings. The MMC (metal matrix composite) coatings with inert α-Al 2 O 3 particles (30 - 90 nm) were electrodeposited from aqueous electrolytes under direct current (DC) and controlled hydrodynamic conditions in a system with a rotating disk electrode (RDE). The chemical composition and microstructure of electrodeposited composites mainly control their functional properties; however, the particles must be uniformly dispersed to exhibit the dispersion-hardening effect. In order to increase the alumina particles incorporation as well as to promote the uniform distribution of the ceramic phase in a matrix, outer ultrasonic field was applied during electrodeposition. The influence of embedded alumina nanoparticles on structural characteristics (morphology, phase composition, residual stresses) of the resulting Ni-W/Al 2 O 3 coatings was investigated in order to obtain a nanocomposite with high hardness and relatively low residual stresses. Surface and cross-section morphology and the chemical composition of deposits was examined in the scanning electron microscope, the EDS technique was used. Microstructure and phase composition were determined by transmission electron microscopy and X-ray diffraction. Based on microstructural and micromechanical properties of the coatings, the optimum conditions for obtaining crack-free homogeneous Ni-W/Al 2 O 3 composite coatings have been determined.

  2. Study on modernization processes in the coating metal surfaces (plain bearings by thermal spraying

    Directory of Open Access Journals (Sweden)

    Elena IRIMIE

    2011-09-01

    Full Text Available Knowledge accumulated within the metal coating through thermal spraying allows the understanding of aspects related to the coat structure phenomena, in this case of the routs that need to be followed in order to create strong and stabile connections between the coats subsided through thermal spraying, between the particles that compose those coats, respectively. However, all this knowledge does not ensure the understanding of some practical situations that are apparently paradoxes, as for instance the absence of tin bronze adherence to ignobly steel holders, the perfect adherence of bronze to the aluminum on the same types of holders, in the context in which both elements, tin and aluminum, respectively are found in equal quantity in the two type of bonze that maintain them in solid solutions (below 10%.The parallel study in the sinter antifriction domain has offered information regarding the optimal correlation between the composition of antifriction material and the required type of application, the optimal pinches level and the way that this morphological characteristic may be influenced. By experimental research it is necessary to determine the conditions under which such coverage can be obtained by thermal spraying of the metal coatings.

  3. Metal-organic aerogel as a coating for solid-phase microextraction

    Energy Technology Data Exchange (ETDEWEB)

    Saraji, Mohammad, E-mail: saraji@cc.iut.ac.ir; Shahvar, Ali

    2017-06-22

    An iron-based metal-organic aerogel was synthesized using metal-organic framework nanoparticles and applied as a fiber coating for solid-phase microextraction (SPME). Chemical, thermal and morphological characteristics of the material were investigated. Headspace SPME followed by gas chromatography-electron capture detection was used for the determination of chlorobenzenes in the environmental samples. The key experimental factors affecting the extraction efficiency of the analytes, such as ionic strength, extraction and desorption temperature, and extraction time were investigated and optimized. The applicability of the coating for the extraction of chlorobenzenes from the environmental samples including river and tap water, sludge, and coastal soil was evaluated. The detection limits were in the range of 0.1–60 ng L{sup −1}. The relative standard deviations were between 2.0 and 5.0%. The extraction recovery of the analytes was in the range of 88–100%. Compared to the commercial PDMS fiber, the present fiber showed better extraction efficiency. - Highlights: • Metal-organic aerogel was synthesized and used as a novel fiber coating for SPME. • The new coating material showed high surface area and good thermal stability. • GC-ECD was used for determination of chlorobenzenes in environmental samples. • The method showed fast extraction and better efficiency than PDMS commercial fiber.

  4. Resizing metal-coated nanopores using a scanning electron microscope.

    Science.gov (United States)

    Chansin, Guillaume A T; Hong, Jongin; Dusting, Jonathan; deMello, Andrew J; Albrecht, Tim; Edel, Joshua B

    2011-10-04

    Electron beam-induced shrinkage provides a convenient way of resizing solid-state nanopores in Si(3) N(4) membranes. Here, a scanning electron microscope (SEM) has been used to resize a range of different focussed ion beam-milled nanopores in Al-coated Si(3) N(4) membranes. Energy-dispersive X-ray spectra and SEM images acquired during resizing highlight that a time-variant carbon deposition process is the dominant mechanism of pore shrinkage, although granular structures on the membrane surface in the vicinity of the pores suggest that competing processes may occur. Shrinkage is observed on the Al side of the pore as well as on the Si(3) N(4) side, while the shrinkage rate is observed to be dependent on a variety of factors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Bioactive and Porous Metal Coatings for Improved Tissue Regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, A. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2000-01-01

    Our first objective was to develop the SIM process for the deposition of calcium phosphate films. This process is based on the observation that, in nature, living organisms use macromolecules to control the nucleation and growth of mineral phases. These macromolecules act as templates where various charged functional groups, contained within the molecule, can interact with the ions in the surrounding media, thus stimulating crystal nucleation and growth. Rather than using complex proteins or biopolymers, surface modification schemes were developed to place simple functional groups on the underlying substrate using self-assembling monolayers. Once the substrate was chemically modified, it was then placed into an aqueous solution containing soluble precursors of the desired mineral coating. Solution pH, ionic concentration and temperature is maintained in a regime where the solution is supersaturated with respect to the desired mineral phase, thereby creating the driving force for nucleation and growth.

  6. Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques

    Energy Technology Data Exchange (ETDEWEB)

    Seltzer, S. J.; Michalak, D. J.; Donaldson, M. H.; Balabas, M. V.; Barber, S. K.; Bernasek, S. L.; Bouchiat, M.-A.; Hexemer, A.; Hibberd, A. M.; Jackson Kimball, D. F.; Jaye, C.; Karaulanov, T.; Narducci, F. A.; Rangwala, S. A.; Robinson, H. G.; Shmakov, A. K.; Voronov, D. L.; Yashchuk, V. V.; Pines, A.; Budker, D.

    2010-10-11

    Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.

  7. Surface engineering glass-metal coatings designed for induction heating of ceramic components

    International Nuclear Information System (INIS)

    Khan, Amir Azam; Labbe, Jean Claude

    2014-01-01

    The term Surface Engineering is of relatively recent origin and use, however, the use of coatings and treatments to render surfaces of materials more suitable for certain application or environment is not new. With the advent of Vacuum Technology, Surface Engineering has gained a whole new impetus, whereby expensive materials with adequate mechanical, chemical and thermal properties are being coated or treated on their surfaces in order to achieve what is called as Surface Engineered materials. The present paper presents an overview of recent achievements in Surface Engineering and gives a detailed view of a specific application where glass-metal composite coatings were deposited on ceramic components in order to render them sensitive to induction heating. Sintered glaze coatings containing silver particles in appropriate concentration can be used for the induction heating of porcelain. Mixtures of glass ceramic powders with silver are used to prepare self-transfer patterns, which are deposited over porcelain. Several configurations of these coatings, which are aesthetic to start with, are employed and heating patterns are recorded. The microstructure of these coatings is discussed in relation to the heating ability by a classical household induction system. The results show that this technique is practical and commercially viable

  8. Surface engineering glass-metal coatings designed for induction heating of ceramic components

    International Nuclear Information System (INIS)

    Khan, A. A.; Labbe, J. C.

    2013-01-01

    The term Surface Engineering is of relatively recent origin and use, however, the use of coatings and treatments to render surfaces of materials more suitable for certain application or environment is not new. With the advent of Vacuum Technology, Surface Engineering has gained a whole new impetus, whereby expensive materials with adequate mechanical, chemical and thermal properties are being coated or treated on their surfaces in order to achieve what is called as Surface Engineered materials. The present paper presents an overview of recent achievements in Surface Engineering and gives a detailed view of a specific application where glass-metal composite coatings were deposited on ceramic components in order to render them sensitive to induction heating. Sintered glaze coatings containing silver particles in appropriate concentration can be used for the induction heating of porcelain. Mixtures of glass ceramic powders with silver are used to prepare self-transfer patterns, which are deposited over porcelain. Several configurations of these coatings, which are aesthetic to start with, are employed and heating patterns are recorded. The microstructure of these coatings is discussed in relation to the heating ability by a classical household induction system. The results show that this technique is practical and commercially viable. (author)

  9. Zirconia based ceramic coating on a metal with plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Akatsu, T; Shinoda, Y; Wakai, F [Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, 4259-R3-24, Nagatsuta, Midori, Yokohama (Japan); Kato, T, E-mail: akatsu.t.aa@m.titech.ac.jp [Department of Materials Science and Engineering, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259-R3-24, Nagatsuta, Midori, Yokohama (Japan)

    2011-10-29

    We challenge to fabricate a thermal barrier coating (TBC) made of ZrO{sub 2} based ceramics on a Ni based single crystal superalloy with plasma electrolytic oxidation (PEO) by incorporating metal species from electrolyte into the coating. The PEO process is carried out on the superalloy galvanized with aluminium for 15min in Na{sub 4}O{sub 7}P{sub 4} solution for an oxygen barrier coating (OBC) and is followed by PEO in K{sub 2}[Zr(CO{sub 3}){sub 2}(OH){sub 2}] solution for TBC. We obtained the following results; (1) Monoclinic-, tetragonal-, cubic-ZrO{sub 2} crystals were detected in TBC. (2) High porosity with large pores was observed near the interface between OBC and TBC. The fine grain structure with a grain size of about 300nm was typically observed. (3) The adhesion strength between PEO coatings and substrate was evaluated to be 26.8{+-}6.6MPa. At the adhesion strength test, PEO coatings fractured around the interface between OBC and TBC. The effect of coating structure on adhesion strength is explained through the change in spark discharge during PEO process.

  10. Performance improvement of an ionic polymer metal composite actuator by parylene thin film coating

    Science.gov (United States)

    Kim, Seong Jun; Lee, In Taek; Lee, Ho-Young; Hyup Kim, Yong

    2006-12-01

    IPMC (ionic polymer-metal composite) is a kind of ionic EAP (electroactive polymer) which is actuated by the movement of cations combined with water molecules in the polymer. The cations and water molecules move due to the applied voltage on the metal electrodes which are located on both sides of the polymer. However, water contained in the polymer gradually evaporates during the actuation and this reduces the performance of the IPMC actuator. To suppress the water evaporation from the IPMC, waterproof material such as parylene, silicone rubber and other polymers were coated on the surface of the IPMC. The displacement, the force and the lifetime of the actuator were observed by using a laser displacement measurement system and a load cell. The water impermeability of the polymer coating with respect to time was measured on a hot plate. Results showed that the parylene coating effectively suppressed the water loss from the IPMC and enlarged the lifetime of the actuator dramatically. However, it was found that parylene has poor adhesion properties to the metal electrode. To improve the adhesion, plasma treatments of argon (Ar), oxygen (O2) and trifluoromethane (CHF3) were performed on the electrode surface before parylene coating. We evaluated the surface morphology change of the electrode after plasma treatment by SEM (scanning electron microscopy) and AFM (atomic force microscopy). In addition, a tape adhesion test and a peel test were performed for quantitative analysis of adhesion strength between the metal electrode and parylene. It was found that the argon plasma treatment was the most effective to improve the adhesion strength between the metal electrode and parylene.

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

    International Nuclear Information System (INIS)

    Schier, V.

    1995-12-01

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

  12. Biodegradable polymer brush as nanocoupled interface for improving the durability of polymer coating on metal surface.

    Science.gov (United States)

    Bedair, Tarek M; Cho, Youngjin; Joung, Yoon Ki; Han, Dong Keun

    2014-10-01

    Metal-based drug-eluting stents (DESs) have severe drawbacks such as peeling-off and cracking of the coated polymer. To prevent the fracture of polymer-coated layer and improve the durability of DES, poly(l-lactide) (PLLA) brushes were synthesized onto cobalt-chromium (Co-Cr or CC) surface through atom transfer radical polymerization (ATRP) of 2-hydroxyethylmethacrylate (HEMA) followed by surface-initiated ring opening polymerization (SI-ROP) of l-lactide. The polymer brushes were then characterized by attenuated total reflection-Fourier transform infrared (ATR-FTIR), water contact angle, ellipsometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All of the unmodified and modified Co-Cr surfaces were coated with a matrix of poly(d,l-lactide) (PDLLA) and sirolimus (SRL). The in vitro drug release profile was measured for 70 days. The PLLA-modified Co-Cr showed a biphasic release pattern in the initial burst followed by a slow release. On the other hand, the unmodified Co-Cr showed fast drug release and detachment of the coated polymer layer due to the instability of the polymer layer on Co-Cr surface. In comparison, the PLLA-modified Co-Cr preserved a uniform coating without detachment even after 6 weeks of degradation test. The platelet morphology and low density of platelet adhered on the modified layer and the SRL-in-PDLLA coated Co-Cr surfaces demonstrated that these samples would be blood compatible. Therefore, the introduction of PLLA brush onto Co-Cr surface is proved to dramatically improve the durability of the coating layer, and it is a promising strategy to prevent the coating defects found in DESs. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Chrome nitride coating reduces wear of small, spherical CrCoMo metal-on-metal articulations in a joint simulator.

    Science.gov (United States)

    Thorkildsen, R; Reigstad, O; Røkkum, M

    2017-03-01

    Metal-on-metal articulations have fallen out of favour in larger joint replacements, but are still used in smaller joints. Coating the articulation has been suggested as one way of reducing wear. We compared a standard 6 mm CrCoMo articulation designed for the carpometacarpal joint of the thumb with a chromium nitride-coated version after 512,000 cycles in a joint simulator. A total of 6 articulations in each group were tested with a unidirectional load of 5 kg in Ringer's solution. We found a statistically significant reduction in weight loss, amount of metallic wear produced and volumetric wear for the chromium nitride-coated articulation. Our findings support the use of chromium nitride coating in order to minimize the amount of metallic wear produced.

  14. Metal separators coated with carbon/resin composite layers for PEFCs

    Energy Technology Data Exchange (ETDEWEB)

    Kitta, Shigehiro [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4 Takeda, Kofu 400-8510 (Japan); Asktechnica Corp., 1488 Ichikawadaimon, Nishi-yatsushiro 409-3601 (Japan); Uchida, Hiroyuki [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4 Takeda, Kofu 400-8510 (Japan); Watanabe, Masahiro [Clean Energy Research Center, University of Yamanashi, 4 Takeda, Kofu 400-8510 (Japan)

    2007-12-31

    A new type of metal separator coated with corrosion-resistant and electronically conductive carbon/resin composite layers has been developed. A flat, stainless steel plate was coated with a thin composite layer, and then ribs were formed of a similar composite over the thin layer as gas flow channels. The composite consisted of graphite, epoxy resin and a phenol hardener. By optimizing the combination and composition of materials, target values for the bulk electric conductivity and the chemical stability in hot water were cleared. The separator pieces exhibited a good corrosion resistance during soaking tests in 0.1 M H{sub 2}SO{sub 4} at 90 C over 2000 h or even at 120 C over 1200 h. The area-specific resistance of the separator coated with the thin protecting layer and the rib layer was less than 13.8 m{omega} cm{sup 2}. (author)

  15. Novel composite cBN-TiN coating deposition method: structure and performance in metal cutting

    International Nuclear Information System (INIS)

    Russell, W.C.; Malshe, A.P.; Yedave, S.N.; Brown, W.D.

    2001-01-01

    Cubic boron nitride coatings are under development for a variety of applications but stabilization of the pure cBN form and adhesion of films deposited by PVD and ion-based methods has been difficult. An alternative method for depositing a composite cBN-TiN film has been developed for wear related applications. The coating is deposited in a two-stage process utilizing ESC (electrostatic spray coating) and CVI (chemical vapor infiltration). Fully dense films of cBN particles evenly dispersed in a continuous TiN matrix have been developed. Testing in metal cutting has shown an increase in tool life (turning - 4340 steel) of three to seven times, depending of machining parameters, in comparison with CVD deposited TiN films. (author)

  16. Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

    Science.gov (United States)

    Mohan, Arun Ram

    Solid deposit formation from jet fuel compromises the fuel handling system of an aviation turbine engine and increases the maintenance downtime of an aircraft. The deposit formation process depends upon the composition of the fuel, the nature of metal surfaces that come in contact with the heated fuel and the operating conditions of the engine. The objective of the study is to investigate the effect of substrate surfaces on the amount and nature of solid deposits in the intermediate regime where both autoxidation and pyrolysis play an important role in deposit formation. A particular focus has been directed to examining the effectiveness of barrier coatings produced by metal organic chemical vapor deposition (MOCVD) on metal surfaces for inhibiting the solid deposit formation from jet fuel degradation. In the first part of the experimental study, a commercial Jet-A sample was stressed in a flow reactor on seven different metal surfaces: AISI316, AISI 321, AISI 304, AISI 347, Inconel 600, Inconel 718, Inconel 750X and FecrAlloy. Examination of deposits by thermal and microscopic analysis shows that the solid deposit formation is influenced by the interaction of organosulfur compounds and autoxidation products with the metal surfaces. The nature of metal sulfides was predicted by Fe-Ni-S ternary phase diagram. Thermal stressing on uncoated surfaces produced coke deposits with varying degree of structural order. They are hydrogen-rich and structurally disordered deposits, spherulitic deposits, small carbon particles with relatively ordered structures and large platelets of ordered carbon structures formed by metal catalysis. In the second part of the study, environmental barrier coatings were deposited on tube surfaces to inhibit solid deposit formation from the heated fuel. A new CVD system was configured by the proper choice of components for mass flow, pressure and temperature control in the reactor. A bubbler was designed to deliver the precursor into the reactor

  17. The erosion performance of cold spray deposited metal matrix composite coatings with subsequent friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Peat, Tom, E-mail: tompeat12@gmail.com [Department of Mechanical & Aerospace Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ (United Kingdom); Galloway, Alexander; Toumpis, Athanasios [Department of Mechanical & Aerospace Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ (United Kingdom); McNutt, Philip [TWI Ltd., Granta Park, Cambridge CB21 6AL (United Kingdom); Iqbal, Naveed [TWI Technology Centre, Wallis Way, Catcliff, Rotherham, S60 5TZ (United Kingdom)

    2017-02-28

    Highlights: • WC-CoCr, Cr{sub 3}C{sub 2}-NiCr and Al{sub 2}O{sub 3} coatings were cold spray deposited on AA5083 and friction stir processed. • The SprayStirred WC-CoCr demonstrated a hardness increase of 100% over the cold sprayed coating. • As-deposited and SprayStirred coatings were examined under slurry erosion test conditions. • Mass and volume loss was measured following 20-min exposure to the slurry. • The WC-CoCr and Al2O3 demonstrated a reduction in volume loss of approx. 40% over the cold sprayed coating. - Abstract: This study forms an initial investigation into the development of SprayStir, an innovative processing technique for generating erosion resistant surface layers on a chosen substrate material. Tungsten carbide – cobalt chromium, chromium carbide – nickel chromium and aluminium oxide coatings were successfully cold spray deposited on AA5083 grade aluminium. In order to improve the deposition efficiency of the cold spray process, coatings were co-deposited with powdered AA5083 using a twin powder feed system that resulted in thick (>300 μm) composite coatings. The deposited coatings were subsequently friction stir processed to embed the particles in the substrate in order to generate a metal matrix composite (MMC) surface layer. The primary aim of this investigation was to examine the erosion performance of the SprayStirred surfaces and demonstrate the benefits of this novel process as a surface engineering technique. Volumetric analysis of the SprayStirred surfaces highlighted a drop of approx. 40% in the level of material loss when compared with the cold spray deposited coating prior to friction stir processing. Micro-hardness testing revealed that in the case of WC-CoCr reinforced coating, the hardness of the SprayStirred material exhibits an increase of approx. 540% over the unaltered substrate and 120% over the as-deposited composite coating. Microstructural examination demonstrated that the increase in the hardness of the

  18. Corrosion resistance and characterization of metallic coatings deposited by thermal spray on carbon steel

    International Nuclear Information System (INIS)

    Sá Brito, V.R.S.; Bastos, I.N.; Costa, H.R.M.

    2012-01-01

    Highlights: ► Five combinations of metallic coatings and intermediate bonds were deposited on carbon steels. ► High strength was reached in adhesion tests. ► Epoxy sealing of coatings improves corrosion resistance. -- Abstract: Carbon steels are not resistant to corrosion and several methods are used in surface engineering to protect them from aggressive environments such as marine. The main objective of this work is the evaluation of mechanical and metallurgical properties of five metallic coatings produced by thermal spray on carbon steel. Five chemical compositions were tested in order to give a large panel of possibility. Coatings were characterized by several methods to result in a screening of their performance. At first, the assessment of microstructural morphology by optical microscopy (OM) and by scanning electron microscopy (SEM) was made. OM and SEM results showed uniformity of deposited layer, low amount of oxides and porosity. The physical properties of coatings were also evaluated by microhardness measurement, adhesion and porosity quantification. The corrosion resistance was analyzed in salt spray and electrochemical polarization tests. In the polarization test, as well as in the salt spray, all sealed conditions presented low corrosion. A new intermediate 78.3Ni20Cr1.4Si0.3Fe alloy was studied in order to reduce pores and microcracks that are frequently found in ordinary 95Ni5Al alloy. Based on the performed characterizations, the findings suggested that the FeCrCo deposition, with an epoxy sealing, is suitable to be used as an efficient coating of carbon steel in aggressive marine environments.

  19. One-step surface selective modification of UV-curable hard coatings with photochemical metal organics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoon Kwang; Park, Chang-Sun; Park, Hyung-Ho, E-mail: hhpark@yonsei.ac.kr

    2016-12-15

    Graphical abstract: This study demonstrates suitable for exceptional hybrid film under UV exposure. A small quantity of the dispersive photochemical precursor Sr 2-ethylhexanoate was mixed and the composition altered from the surface to the bottom, forming an organic layer and a densely concentrated SrO surface layer. The surface-selective SrO strongly enhanced the surface flatness and hardness of the UV-curable organic coating film. - Highlights: • Hybrid bi-layer coating was synthesized through one-pot UV exposure chemical route. • The influence of additive and different reactivity formed densely concentrated SrO surface layer. • Chemical composition and continuous interface between organic and inorganic were analyzed. • Surface flatness and mechanical property were improved by inorganic material. - Abstract: An organic–inorganic hybrid bi-layer film with a selective distribution of inorganic components was synthesized from a one-pot process of UV irradiation. A photochemical metal oxide precursor (Sr 2-ethylhexanoate) varying from 0 to 4 wt% was dispersed in UV-curable coating materials. Under UV exposure, the bi-layer started reacting simultaneously but at different rates due to differences in the two UV-condensable components’ reactivity. The effects of the dispersed inorganic component on the surface morphology and mechanical properties were investigated by atomic force microscopy and nanoindentation, respectively. The reaction process and rates were studied from linkage change using Fourier transform infrared spectroscopy at various UV exposure times (0–30 min). The elemental distribution and the interface on the coating layer were characterized by X-ray photoelectron spectroscopy from Ar etching, revealing continuous and gradual composition changes in depth. The results showed that a flattened and surface-selectively hardened SrO containing the coating film could be obtained by this simple process. Consequently, a small ratio of photochemical

  20. Elastic moduli and elastic anisotropy of cold sprayed metallic coatings

    Czech Academy of Sciences Publication Activity Database

    Seiner, Hanuš; Cizek, J.; Sedlák, Petr; Huang, R.; Cupera, J.; Dlouhý, I.; Landa, Michal

    2016-01-01

    Roč. 291, April (2016), s. 342-347 ISSN 0257-8972 R&D Projects: GA ČR GA13-13616S; GA ČR(CZ) GA13-35890S Grant - others:NETME Centre Plus - národní program udržitelnosti(CZ) LO1202 Institutional support: RVO:61388998 Keywords : kinetic spray * CGDS * elastic properties * metals and alloys * deposition * resonant ultrasound spectroscopy Subject RIV: JG - Metallurgy Impact factor: 2.589, year: 2016 http://ac.els-cdn.com/S0257897216301165/1-s2.0-S0257897216301165-main.pdf?_tid=1083617a-017f-11e6-92e7-00000aacb361&acdnat=1460555773_2e80d3df20843f3af649bf3ac71c8844

  1. Electrically tunable Brillouin fiber laser based on a metal-coated single-mode optical fiber

    Directory of Open Access Journals (Sweden)

    S.M. Popov

    Full Text Available We explore tunability of the Brillouin fiber laser employing Joule heating. For this purpose, 10-m-length of a metal-coated single-mode optical cavity fiber has been directly included into an electrical circuit, like a conductor wire. With the current up to ∼3.5 A the laser tuning is demonstrated over a spectrum range of ∼400 MHz. The observed laser line broadening up to ∼2 MHz is explained by frequency drift and mode-hoping in the laser caused by thermal noise. Keywords: Brillouin fiber laser, Metal-coated optical fiber, Laser tuning, Fiber sensors

  2. Influence of interface on the formation process of polymer coatings on metal

    Directory of Open Access Journals (Sweden)

    O. G. Maksimova

    2016-03-01

    Full Text Available The purpose of this work is in development of the model that allows to investigate the conformations of macromolecules near the interface “dielectric-metal” depending on the conditions of formation of the polymer coating. In the modified model of “sticky tape”, one part of macromolecule is anchored to the metal surface while the other can be elongated due to effective mean (molecular field of dipolar type formed by free ends of other chains. The dynamic Monte-Carlo method for Langmuir’s model is used for calculation of adhesion force taking into account the interaction energy of monomers with the metal surface. It is shown that conformation of polymer chain is defined by temperature conditions of its formation. The obtained results are confirmed by the data of production tests on polymer coatings in JSC “Severstal”.

  3. Bone response to a titanium aluminium nitride coating on metallic implants.

    Science.gov (United States)

    Freeman, C O; Brook, I M

    2006-05-01

    The design, surface characteristics and strength of metallic implants are dependant on their intended use and clinical application. Surface modifications of materials may enable reduction of the time taken for osseointegration and improve the biological response of bio-mechanically favourable metals and alloys. The influence of a titanium aluminium nitride (TAN) coating on the response of bone to commercially pure titanium and austenitic 18/8 stainless steel wire is reported. TAN coated and plain rods of stainless steel and commercially pure titanium were implanted into the mid-shaft of the femur of Wistar rats. The femurs were harvested at four weeks and processed for scanning electron and light microscopy. All implants exhibited a favourable response in bone with no evidence of fibrous encapsulation. There was no significant difference in the amount of new bone formed around the different rods (osseoconduction), however, there was a greater degree of shrinkage separation of bone from the coated rods than from the plain rods (p = 0.017 stainless steel and p = 0.0085 titanium). TAN coating may result in reduced osseointegration between bone and implant.

  4. Improvement of corrosion resistance of transparent conductive multilayer coating consisting of silver layers and transparent metal oxide layers

    International Nuclear Information System (INIS)

    Koike, Katsuhiko; Yamazaki, Fumiharu; Okamura, Tomoyuki; Fukuda, Shin

    2007-01-01

    An optical filter for plasma display panel (PDP) requires an electromagnetic shield with very high ability. The authors investigated a transparent conductive multilayer coating consisting of silver (Ag) layers and transparent metal oxide layers. The durability of the multilayer sputter coating, including the silver layer, is very sensitive to the surrounding atmosphere. For example, after an exposure test they found discolored points on the multilayer sputter coatings, possibly caused by migration of silver atoms in the silver layers. In their investigation, they modified the top surface of the multilayer sputter coatings with transition metals to improve the corrosion resistance of the multilayer coating. Specifically, they deposited transition metals 0.5-2 nm thick on the top surface of the multilayer coatings by sputtering. They chose indium tin oxide (ITO) as the transparent metal oxide. They applied the multilayer sputter coatings of seven layers to a polyethylene terephthalate (PET) film substrate. A cross-sectional structure of the film with the multilayer coatings is PET film/ITO/Ag/ITO/Ag/ITO/Ag/ITO. They evaluated the corrosion resistance of the films by a salt-water immersion test. In the test, they immersed the film with multilayer coatings into salt water, and then evaluated the appearance, transmittance, and electrical resistance of the multilayer coatings. They investigated several transition metals as the modifying material, and found that titanium and tantalum drastically improved the resistance of the multilayer coatings to the salt-water exposure without a significant decline in transmittance. They also investigated the relation between elapsed time after deposition of the modifying materials and resistance to the salt water. Furthermore, they investigated the effects of a heat treatment and an oxide plasma treatment on resistance to the salt water

  5. Chitosan-coated Silica Nanoparticles - A Potential Support for Metal Particles used as Heterogeneous Catalyst

    International Nuclear Information System (INIS)

    Haghighizadeh, A.; Abu Bakar, M.; Ghani, S.A.; Abu Bakar, N.H.H.

    2011-01-01

    In this work a strategy to immobilize noble metal nanoparticles on silica microspheres is proposed. In order to achieve this, monodispersed silica nanoparticles of an average size of 63.5±6.7 nm were synthesized via sol-gel method. Then chitosan was coated onto the silica to create a core/ shell composite with the size range of 66.56±9.78 nm to 79.18±11.87 nm. The noble metal nanoparticles were then synthesized on the shell of the composite through coordination of the respective metal ions to the polymer followed by the subsequent reduction. In this way, the silver particles of average size 6.17±1.83 nm, 9.85±2.60 nm, and 11.80±4.26 nm have been synthesized on the shell successfully. The optimized supported metal particles can be used as a potential heterogeneous catalyst. (author)

  6. Compositions of corrosion-resistant Fe-based amorphous metals suitable for producing thermal spray coatings

    Science.gov (United States)

    Farmer, Joseph C; Wong, Frank M.G.; Haslam, Jeffery J; Ji, Xiaoyan; Day, Sumner D; Blue, Craig A; Rivard, John D.K.; Aprigliano, Louis F; Kohler, Leslie K; Bayles, Robert; Lemieux, Edward J; Yang, Nancy; Perepezko, John H; Kaufman, Larry; Heuer, Arthur; Lavernia, Enrique J

    2013-09-03

    A method of coating a surface comprising providing a source of amorphous metal that contains manganese (1 to 3 atomic %), yttrium (0.1 to 10 atomic %), and silicon (0.3 to 3.1 atomic %) in the range of composition given in parentheses; and that contains the following elements in the specified range of composition given in parentheses: chromium (15 to 20 atomic %), molybdenum (2 to 15 atomic %), tungsten (1 to 3 atomic %), boron (5 to 16 atomic %), carbon (3 to 16 atomic %), and the balance iron; and applying said amorphous metal to the surface by a spray.

  7. Wakefield radiation from the open end of an internally coated metallic tube

    Directory of Open Access Journals (Sweden)

    M. Ivanyan

    2014-07-01

    Full Text Available In this paper the problem of radiation from the open end of a semi-infinite circular metallic waveguide with perfectly conducting walls and a thin internal low-conducting metal coating is considered. Electromagnetic fields are generated by the ultrarelativistic point charge moving along the axis of the waveguide. The far fields of radiation are obtained using the near-field to far-field recovery technique. The technique is extended for the nonmonochromatic waves. It is shown that the radiation has a narrow-band and narrow-directional character.

  8. Synthesis of high T.sub.C superconducting coatings and patterns by melt writing and oxidation of metallic precursor alloys

    Science.gov (United States)

    Gao, Wei; Vander Sande, John B.

    1998-01-01

    A method is provided for fabrication of superconducting oxides and superconducting oxide composites and for joining superconductors to other materials. A coating of a molten alloy containing the metallic elements of the oxide is applied to a substrate surface and oxidized to form the superconducting oxide. A material can be contacted to the molten alloy which is subsequently oxidized joining the material to the resulting superconducting oxide coating. Substrates of varied composition and shape can be coated or joined by this method.

  9. Isothermal oxidation of metallic coatings deposited by a water-stabilized plasma gun

    Czech Academy of Sciences Publication Activity Database

    Voleník, Karel; Nop, P.; Kopřiva, P.; Kolman, Blahoslav Jan; Dubský, Jiří

    2006-01-01

    Roč. 44, č. 1 (2006), s. 41-48 ISSN 0023-432X R&D Projects: GA ČR(CZ) GA106/03/0710 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * metallic coatings * oxidation tests * oxidation kinetics * oxide structure * element distribution Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.138, year: 2006

  10. Biocompatibility evaluation of sputtered zirconium-based thin film metallic glass-coated steels

    Directory of Open Access Journals (Sweden)

    Subramanian B

    2015-10-01

    Full Text Available Balasubramanian Subramanian,1 Sundaram Maruthamuthu,2 Senthilperumal Thanka Rajan1 1Electrochemical Material Science Division, 2Corrosion and Materials Protection Division, Central Electrochemical Research Institute, Karaikudi, India Abstract: Thin film metallic glasses comprised of Zr48Cu36Al8Ag8 (at.% of approximately 1.5 µm and 3 µm in thickness were prepared using magnetron sputtering onto medical grade 316L stainless steel. Their structural and mechanical properties, in vitro corrosion, and antimicrobial activity were analyzed. The amorphous thin film metallic glasses consisted of a single glassy phase, with an absence of any detectable peaks corresponding to crystalline phases. Elemental composition close to the target alloy was noted from EDAX analysis of the thin film. The surface morphology of the film showed a smooth surface on scanning electron microscopy and atomic force microscopy. In vitro electrochemical corrosion studies indicated that the zirconium-based metallic glass could withstand body fluid, showing superior resistance to corrosion and electrochemical stability. Interactions between the coated surface and bacteria were investigated by agar diffusion, solution suspension, and wet interfacial contact methods. The results indicated a clear zone of inhibition against the growth of microorganisms such as Escherichia coli and Staphylococcus aureus, confirming the antimicrobial activity of the thin film metallic glasses. Cytotoxicity studies using L929 fibroblast cells showed these coatings to be noncytotoxic in nature. Keywords: thin film metallic glasses, sputtering, biocompatibility, corrosion, antimicrobial activity

  11. High-Temperature Solid Lubricant Coating by Plasma Spraying Using Metal-Metal Clad Powders

    Science.gov (United States)

    Zhang, Tiantian; Lan, Hao; Yu, Shouquan; Huang, Chuanbing; Du, Lingzhong; Zhang, Weigang

    2017-08-01

    NiCr/Ag-Mo composite coating was fabricated by atmospheric plasma spray technology using clad powders as the feedstock. Its tribological properties at variable temperature were evaluated using a ball-on-disk high-temperature tribometer in air. The results showed that compared with NiCr, the NiCr/Ag-Mo composite coating exhibited better lubrication effect and higher wear resistance at all test temperatures, especially above 600 °C. At 800 °C, NiCr/Ag-Mo composite coating showed the lowest friction coefficient of about 0.2 and its corresponding wear rate reached 2.5 × 10-5 mm3/Nm. Characterizations of NiCr/Ag-Mo composite coating revealed that at temperatures below 400 °C, Ag was smeared and spread onto the wear surface, reducing the friction and wear. At temperature above 500 °C, the Ag2MoO4 lubrication film formed by tribo-oxidation significantly improved the coating's lubrication effect and wear resistance.

  12. Fracture resistance of dental nickel–titanium rotary instruments with novel surface treatment: Thin film metallic glass coating

    Directory of Open Access Journals (Sweden)

    Chih-Wen Chi

    2017-05-01

    Conclusion: The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure.

  13. Effects of metal coatings on adhesive characteristics of Gecko-like microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Kim Kyu Hye; An, Tea Chang; Hwang, Hui Yun [Dept. of Mechanical Design Engineering, Andong National University, Andong (Korea, Republic of)

    2015-11-15

    Recently, there have been several studies on the inspiration and application of optimized natural structures. One study introduced a new adhesion method that was inspired by the feet of geckos because of their superior features such as high adhesion strength, ease-of-removal, and they are environmentally friendly. Various micro- or nano-structures were fabricated and tested for gecko-like dry adhesives, but gecko-like dry adhesives that were developed became easily worn from frequent use. In this study, we propose a metal-coating method to improve the durability of gecko-like dry adhesives. We evaluate the initial adhesion strength and durability by performing repeated adhesion tests on a glass plate. The initial adhesive strength of gold-coated micro-structures was 60% of that for non-coated ones. However, the adhesive strength of gold-coated micro-structures was kept as 58% of their initial adhesion strength, while that of non-coated ones was only 40%.

  14. Effects of metal coatings on adhesive characteristics of Gecko-like microstructures

    International Nuclear Information System (INIS)

    Kim Kyu Hye; An, Tea Chang; Hwang, Hui Yun

    2015-01-01

    Recently, there have been several studies on the inspiration and application of optimized natural structures. One study introduced a new adhesion method that was inspired by the feet of geckos because of their superior features such as high adhesion strength, ease-of-removal, and they are environmentally friendly. Various micro- or nano-structures were fabricated and tested for gecko-like dry adhesives, but gecko-like dry adhesives that were developed became easily worn from frequent use. In this study, we propose a metal-coating method to improve the durability of gecko-like dry adhesives. We evaluate the initial adhesion strength and durability by performing repeated adhesion tests on a glass plate. The initial adhesive strength of gold-coated micro-structures was 60% of that for non-coated ones. However, the adhesive strength of gold-coated micro-structures was kept as 58% of their initial adhesion strength, while that of non-coated ones was only 40%

  15. Cytocompatibility of Siloxane-Containing Vaterite/Poly(l-lactic acid Composite Coatings on Metallic Magnesium

    Directory of Open Access Journals (Sweden)

    Shinya Yamada

    2013-12-01

    Full Text Available Poly(l-lactic acid-based films which include 60 wt % of vaterite (V or siloxane-containing vaterite (SiV were coated on a pure magnesium substrate, denoted by PLLA/V or PLLA/SiV, respectively, to suppress early corrosion and improve its cytocompatibility. Both coating films adhered to the Mg substrate with 2.3–2.8 MPa of tensile bonding strength. Soaking test for 7 days in α-modified minimum essential medium revealed that the morphological instability of the PLLA/V film caused a higher amount of Mg2+ ion to be released from the coating sample. On the other hand, in the case of the coating with the PLLA/SiV film, no morphological change even after the soaking test was observed, owing to the suppression of the degradation rate. In cell culture tests, the proliferation of mouse osteoblast-like cell (MC3T3-E1 was significantly enhanced by both coatings, in comparison with the uncoated magnesium substrate. The cell morphology revealed that a few less-spread cells were observed on the PLLA/V film, while more elongated cells were done on the PLLA/SiV film. The cells on the PLLA/SiV film exhibited an extremely higher alkaline phosphatase activity after 21 days of incubation than that on the PLLA/V one. The PLLA/SiV film suppressed the early corrosion and enhanced cytocompatibility on metallic magnesium.

  16. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Science.gov (United States)

    2010-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits...

  17. A study of TiN-coated metal-on-polymer bearing materials for hip prosthesis

    Science.gov (United States)

    Lee, Sung Bai; Choi, Jin Young; Park, Won Woong; Jeon, Jun Hong; Won, Sung Ok; Byun, Ji Young; Lim, Sang Ho; Han, Seung Hee

    2010-08-01

    The TiN-coated metal-on-polymer hip prosthetic pair has the potential to reduce wear debris of UHMWPE (ultra-high molecular weight polyethylene) and to prevent metallic-ion-induced cytotoxicity. However, high quality and adherent film is a key to the clinical success of hip prostheses. In this study, titanium nitride (TiN) films were deposited on stainless steel using plasma immersion ion implantation & deposition (PIII&D) technique to create high-quality film and an adherent interface. The chemical state and composition were analyzed by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and energy dispersive spectroscopy (EDS). The mechanical properties of the films were characterized using a micro-hardness tester and a pin-on-disk wear tester, and an x-ray diffractometer (XRD) was used for a crystallographic analysis. The PIII&D-treated TiN films showed a stoichiometric and (200) preferred orientation and micro-hardness up to 150 % higher than untreated film. A TiN-coated specimen using the PIII&D process also showed less UHMWPE wear compared to untreated specimens. The volumetric wear rate of UHMWPE could be reduced by as much as 42 % compared to when Co-Cr alloy was used. The results of this study show that advanced TiN-coating via the PIII&D process is a viable means of reducing UHMWPE wear in the metal-on-polymer bearing couple.

  18. Sensing of heavy metal ions by intrinsic TMV coat protein fluorescence.

    Science.gov (United States)

    Bayram, Serene S; Green, Philippe; Blum, Amy Szuchmacher

    2018-04-15

    We propose the use of a cysteine mutant of TMV coat protein as a signal transducer for the selective sensing and quantification of the heavy metal ions, Cd 2+ , Pb 2+ , Zn 2+ and Ni 2+ based on intrinsic tryptophan quenching. TMV coat protein is inexpensive, can be mass-produced since it is expressed and extracted from E-coli. It also displays several different functional groups, enabling a wide repertoire of bioconjugation chemistries; thus it can be easily integrated into functional devices. In addition, TMV-ion interactions have been widely reported and utilized for metallization to generate organic-inorganic hybrid composite novel materials. Building on these previous observations, we herein determine, for the first time, the TMV-ion binding constants assuming the static fluorescence quenching model. We also show that by comparing TMV-ion interactions between native and denatured coat protein, we can distinguish between chemically similar heavy metal ions such as cadmium and zinc ions. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Effect of metallic coating on the properties of copper-silicon carbide composites

    Science.gov (United States)

    Chmielewski, M.; Pietrzak, K.; Teodorczyk, M.; Nosewicz, S.; Jarząbek, D.; Zybała, R.; Bazarnik, P.; Lewandowska, M.; Strojny-Nędza, A.

    2017-11-01

    In the presented paper a coating of SiC particles with a metallic layer was used to prepare copper matrix composite materials. The role of the layer was to protect the silicon carbide from decomposition and dissolution of silicon in the copper matrix during the sintering process. The SiC particles were covered by chromium, tungsten and titanium using Plasma Vapour Deposition method. After powder mixing of components, the final densification process via Spark Plasma Sintering (SPS) method at temperature 950 °C was provided. The almost fully dense materials were obtained (>97.5%). The microstructure of obtained composites was studied using scanning electron microscopy as well as transmission electron microscopy. The microstructural analysis of composites confirmed that regardless of the type of deposited material, there is no evidence for decomposition process of silicon carbide in copper. In order to measure the strength of the interface between ceramic particles and the metal matrix, the micro tensile tests have been performed. Furthermore, thermal diffusivity was measured with the use of the laser pulse technique. In the context of performed studies, the tungsten coating seems to be the most promising solution for heat sink application. Compared to pure composites without metallic layer, Cu-SiC with W coating indicate the higher tensile strength and thermal diffusitivy, irrespective of an amount of SiC reinforcement. The improvement of the composite properties is related to advantageous condition of Cu-SiC interface characterized by well homogenity and low porosity, as well as individual properties of the tungsten coating material.

  20. Novel biopolymer-coated hydroxyapatite foams for removing heavy-metals from polluted water.

    Science.gov (United States)

    Vila, M; Sánchez-Salcedo, S; Cicuéndez, M; Izquierdo-Barba, I; Vallet-Regí, María

    2011-08-15

    3D-macroporous biopolymer-coated hydroxyapatite (HA) foams have been developed as potential devices for the treatment of lead, cadmium and copper contamination of consumable waters. These foams have exhibited a fast and effective ion metal immobilization into the HA structure after an in vitro treatment mimicking a serious water contamination case. To improve HA foam stability at contaminated aqueous solutions pH, as well as its handling and shape integrity the 3D-macroporous foams have been coated with biopolymers polycaprolactone (PCL) and gelatine cross-linked with glutaraldehyde (G/Glu). Metal ion immobilization tests have shown higher and fast heavy metals captured as function of hydrophilicity rate of biopolymer used. After an in vitro treatment, foam morphology integrity is guaranteed and the uptake of heavy metal ions rises up to 405 μmol/g in the case of Pb(2+), 378 μmol/g of Cu(2+) and 316 μmol/g of Cd(2+). These novel materials promise a feasible advance in development of new, easy to handle and low cost water purifying methods. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Biocompatibility evaluation of sputtered zirconium-based thin film metallic glass-coated steels.

    Science.gov (United States)

    Subramanian, Balasubramanian; Maruthamuthu, Sundaram; Rajan, Senthilperumal Thanka

    2015-01-01

    Thin film metallic glasses comprised of Zr48Cu36Al8Ag8 (at.%) of approximately 1.5 μm and 3 μm in thickness were prepared using magnetron sputtering onto medical grade 316L stainless steel. Their structural and mechanical properties, in vitro corrosion, and antimicrobial activity were analyzed. The amorphous thin film metallic glasses consisted of a single glassy phase, with an absence of any detectable peaks corresponding to crystalline phases. Elemental composition close to the target alloy was noted from EDAX analysis of the thin film. The surface morphology of the film showed a smooth surface on scanning electron microscopy and atomic force microscopy. In vitro electrochemical corrosion studies indicated that the zirconium-based metallic glass could withstand body fluid, showing superior resistance to corrosion and electrochemical stability. Interactions between the coated surface and bacteria were investigated by agar diffusion, solution suspension, and wet interfacial contact methods. The results indicated a clear zone of inhibition against the growth of microorganisms such as Escherichia coli and Staphylococcus aureus, confirming the antimicrobial activity of the thin film metallic glasses. Cytotoxicity studies using L929 fibroblast cells showed these coatings to be noncytotoxic in nature.

  2. Characterization and fabrication of fully metal-coated scanning near-field optical microscopy SiO2 tips.

    Science.gov (United States)

    Aeschimann, L; Akiyama, T; Staufer, U; De Rooij, N F; Thiery, L; Eckert, R; Heinzelmann, H

    2003-03-01

    The fabrication of silicon cantilever-based scanning near-field optical microscope probes with fully aluminium-coated quartz tips was optimized to increase production yield. Different cantilever designs for dynamic- and contact-mode force feedback were implemented. Light transmission through the tips was investigated experimentally in terms of the metal coating and the tip cone-angle. We found that transmittance varies with the skin depth of the metal coating and is inverse to the cone angle, meaning that slender tips showed higher transmission. Near-field optical images of individual fluorescing molecules showed a resolution thermocouple showed no evidence of mechanical defect or orifice formation by thermal effects.

  3. Anticorrosive coating of SixOyCz on metallic substrates applied with the plasma CVD technique

    International Nuclear Information System (INIS)

    Perillo, P; Lasorsa, C; Versaci, R

    2006-01-01

    This work deals with the production of anticorrosive coatings of Si x O y C z on metallic substrates by PECVD (Plasma Enhanced Chemical Vapor Deposition) in a two layer coating, with a gaseous mixture using methyltrimethoxysilane (Z6070) with the contribution of O 2 and methane as reactive gases. The process involves two steps, the first with the substrate thermalized to 500 o C and the second step with the substrate at room temperature. In the first step the process is carried out with the mixture of O 2 and Z6070, in the second step methane is added to the mixture of the plasma forming gases. The coatings were carried out on AISI 410 stainless steel, AISI M2 steel, titanium and AA6061 aluminum substrates. This work presents the preliminary results of the electrochemical evaluation and the mechanical properties of the coating. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS/ESCA ), and scanning electron microscopy were used for this study. Electrochemical techniques were used to study the reaction to the corrosion of the coatings. Potentiodynamic polarization curves were prepared in a solution of 5% H 2 SO 4 and in NaCl 0,1M. The tests were undertaken at room temperature. This process is presented as an alternative to the conventional immersion processes by the sol-gel method, which produces the polymerization of the reagent as a result of the effect of the oxygen from the environment, while the plasma process produces very different chemical reactions in the center of the plasma itself with coatings also different (CW)

  4. Influence of substrate metal alloy type on the properties of hydroxyapatite coatings deposited using a novel ambient temperature deposition technique.

    Science.gov (United States)

    Barry, J N; Cowley, A; McNally, P J; Dowling, D P

    2014-03-01

    Hydroxyapatite (HA) coatings are applied widely to enhance the level of osteointegration onto orthopedic implants. Atmospheric plasma spray (APS) is typically used for the deposition of these coatings; however, HA crystalline changes regularly occur during this high-thermal process. This article reports on the evaluation of a novel low-temperature (alloy substrates. This study addresses the suitability of the CoBlast technique for the deposition of HA coatings on a number of alternative metal alloys utilized in the fabrication of orthopedic devices. In addition to titanium grade 5, both cobalt chromium and stainless steel 316 were investigated. In this study, HA coatings were deposited using both the CoBlast and the plasma sprayed techniques, and the resultant HA coating and substrate properties were evaluated and compared. The CoBlast-deposited HA coatings were found to present similar surface morphologies, interfacial properties, and composition irrespective of the substrate alloy type. Coating thickness however displayed some variation with the substrate alloy, ranging from 2.0 to 3.0 μm. This perhaps is associated with the electronegativity of the metal alloys. The APS-treated samples exhibited evidence of both coating, and significantly, substrate phase alterations for two metal alloys; titanium grade 5 and cobalt chrome. Conversely, the CoBlast-processed samples exhibited no phase changes in the substrates after depositions. The APS alterations were attributed to the brief, but high-intensity temperatures experienced during processing. Copyright © 2013 Wiley Periodicals, Inc.

  5. Soluble salts: their incidence on the protection of metallic structures by paint coatings

    International Nuclear Information System (INIS)

    Morcillo, M.

    2003-01-01

    The presence of soluble salts at the metal/paint interface is known to have a detrimental effect on the integrity of most paint systems. Though this is a long-standing problem, it has recently come to receive greater attention from the protective coatings industry. In the paper the following points are reviewed: degradation mechanisms of the metal/paint system, the role of the metallic substrate, the nature, origin and detection os soluble salts, expected levels of soluble salts in practice, critical thresholds of soluble salts and risk levels for premature failures, role of the type and thickness of paint systems and exposure conditions, and prevention measures. The author presents an overview of the subject, making reference to the related research that has been carried out by him and his co-workers over the last 16 years. (Author) 58 refs

  6. Improved Plasticity of Ti-Based Bulk Metallic Glass at Room Temperature by Electroless Thin Nickel Coating

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2017-12-01

    Full Text Available By restricting the dilated deformation, surface modification can stimulate multiple shear banding and improve the plasticity of bulk metallic glasses (BMGs. Aimed at modifying the surface of BMGs by thin layers, a crystalline Ni coating with ultrafine grains was coated on the surface of a Ti-based BMG by electroless plating. With a thickness of about 10 μm, the prepared thin coating could effectively limit the fast propagation of primary shear bands and stimulate the nucleation of multiple shear bands. As a result, the compression plasticity of the coated Ti-based BMG was improved to about 3.7% from near 0% of the non-coated BMG. Except for a small amount of Ni coating was adhered to the BMG substrate after fracture, most of the coatings were peeled off from the surface. It can be attributed to the abnormal growth of some coarse grains/particles in local region of the coating, which induces a large tensile stress at the interface between the coating and the BMG substrate. It is suggested that, for electroless nickel plating, improving the adhesive bonding strength between the coating and the substrate has a better geometric restriction effect than simply increasing the thickness of the coating.

  7. Metal-dusting resistance of uncoated and coated iron and nickel base materials against metal-dusting in heat treatment furnaces with carbonaceous atmospheres

    International Nuclear Information System (INIS)

    Kleingries, Mirko; Ackermann, Helen; Lucka, Klaus; Hoja, Timo; Mehner, Andeas; Zoch, Hans-Werner; Altena, Herwig

    2010-01-01

    Metal-Dusting is a well-known corrosion problem that occurs in carburizing atmospheres in industrial thermal processing plants. In literature almost no quantitative data on the metal dusting resistance of typical alloys employed in industrial furnaces are available. Therefore, a series of experiments with uncoated and sol gel ZrO 2 coated high temperature materials was conducted in order to quantify their metal dusting behaviour under conditions close to those in case hardening furnaces. The experimental results show a strong influence of the surface conditions on the alloys resistance and a noticeable enhancement of the resistance by sol gel coatings. (orig.)

  8. Synthesis and characterization of Cerium-doped hydroxyapatite/polylactic acid composite coatings on metal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Qiuhua, E-mail: yuanqiuh@szu.edu.cn; Qin, Caoping; Wu, Jianbo; Xu, Anping; Zhang, Ziqiang; Liao, Junquan; Lin, Songxin; Ren, Xiangzhong; Zhang, Peixin

    2016-10-01

    Ce-doped hydroxyapatite/polylactic acid (HA/PLA) composites serving as implant coatings have rarely been studied by other researchers in recent years. This paper was focused to study the existence of Ce ions in structure, chemical composition and surface morphology of HA and its composite coatings. Ce-doped HA powders were synthesized by chemical precipitation method with different Ce molar fractions (0(pure HA), 0.5 mol%, 1 mol% and 2 mol%). And Ce-doped HA/PLA composite coatings were fabricated for the first time on stainless steel substrates by spin coating technique. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) coupled with energy dispersive X-ray detector (EDX), thermo gravimetric-differential thermal analysis (TG-DTA) and X-ray photoelectron spectroscopy (XPS). The results showed that Ce ions were doped into the crystal lattice of apatite successfully. The (Ce + Ca)/P atomic ratios in the doped HA/PLA samples ranged from 1.614 to 1.673, which were very close to the theoretical value of 1.67 for the stoichiometric HA. The addition of PLA could keep metal substrates from catalyzing the decomposition of HA. TG-DTA analysis indicated that Ce-doped HA powder had high thermal stability, and the SEM micrographs revealed that the surface topography of Ce-doped HA/PLA composite coatings was uniform and dense when the Ce molar fraction was 2 mol%. XPS results indicated that the Ce ions doped in HA showed mixed valences of Ce{sup 3+} and Ce{sup 4+}. - Highlights: • Ce-doped HA composite coatings were synthesized by spin-coating technique for the first time. • Ce ions were demonstrated to dope into HA crystal lattice successfully. • The addition of PLA could keep metal substrates from catalyzing the decomposition of HA. • XPS results showed that Ce ions doped in HA have mixed valences of Ce{sup 3+} and Ce{sup 4+}.

  9. Investigation of Surfactant Type, Dosage and Ultrasonication Temperature Control on Dispersity of Metal-Coated Multi-Walled Carbon Nanotubes.

    Science.gov (United States)

    Liang, Xiaoning; Li, Wei

    2016-04-01

    We studied the dispersity of multi-walled carbon nanotubes (MWNTs) combined with different metal- lic particles (Ni and Fe). An ultrasonic-assisted water-bath dispersion process was used to dis- perse the metal-coated MWNTs in different solutions and the dispersity was measured using an ultraviolet-visible spectrophotometer. The dispersity and morphology of the MWNTs were characterized using field-emission scanning electron microscopy (FE-SEM) together with digital image processing technology. Effects of dispersant type (sodium dodecyl benzene sulfonate (SDBS), oleic acid, and polymer (TNEDIS)) and surfactant dosage on the dispersity of the metal-coated MWNTs were investigated under controlled and uncontrolled temperatures and results were compared with those from the untreated MWNTs. The results showed that the negative effects of temperature on the ultrasonic dispersion process could be eliminated through a temperature-controlled system. Moreover, the TNEDIS, SDBS, and oleic acid were arranged in the descending order of the dispersion effect degree. The untreated MWNTs, Ni-coated MWNTs, and Fe-coated MWNTs were arranged in the descending degree of dispersity order. Since the metal coating makes the MWNTs harder and more fragile, the metal-coated MWNTs are more likely to fracture during the ultrasonic dispersion process.

  10. Transparent Si–DLC coatings on metals with high repetition bi-polar pulses of a PBII system

    Energy Technology Data Exchange (ETDEWEB)

    Ikeyama, Masami, E-mail: ikeyama3@aist.go.jp; Sonoda, Tsutomu, E-mail: tsutomu.sonoda@aist.go.jp

    2013-07-15

    Diamond-like carbon (DLC) is widely used because of its good properties. However, the color of DLC is usually dark brown or black. Recently, we have made fairly transparent Si contained DLC (Si–DLC) coatings in visible light region. The fairly transparent Si–DLC was made by using our original bi-polar pulse type plasma based ion implantation (PBII) system, with recently introduced high slew rate pulse power supply. The colors of metal sample surface were uniformly changed as subdued red, yellow, subdued green and subdued blue or violet, with the change of Si–DLC coating’s thickness. The colors come from the interference between reflected lights at the surface of the Si–DLC coatings and the surface of the metal samples. The colors were also changed with the angle of glancing. Estimated refractive indexes show well agreements among almost all Si–DLC coatings, instead of the differences of coating conditions. Generally, the longer coating time or slower coating process makes the higher refractive index in near infrared region. Estimated band gap of a Si–DLC coating was about 1.5 eV. The developed Si–DLC coatings must be useful as not only protective but also decorative coatings.

  11. Determination of the coefficient of dynamic friction between coatings of alumina and metallic materials

    Science.gov (United States)

    Santos, A.; Córdoba, E.; Ramírez, Z.; Sierra, C.; Ortega, Y.

    2017-12-01

    This project aims to determine the coefficient of dynamic friction between micrometric size coatings of alumina and metallic materials (Steel and aluminium); the methodology used to achieve the proposed objective consisted of 4 phases, in the first one was developed a procedure that allowed, from a Pin on Disk machine built based on the specifications given by the ASTM G99-05 standard (Standard test method for wear tests with a Pin on Disk machine), to determine the coefficient of dynamic friction between two materials in contact; subsequently the methodology was verified through tests between steel-steel and steel-aluminium, due to these values are widely reported in the literature; as a third step, deposits of alumina particles of micrometric size were made on a steel substrate through thermal spraying by flame; finally, the tests were carried out between pins of steel of aluminium and alumina coating to determine the coefficients of dynamic friction between these two surfaces. The results of the project allowed to verify that the developed methodology is valid to obtain coefficients of dynamic friction between surfaces in contact since the percentages of error were of 3.5% and 2.1% for steel-steel and aluminium-steel, respectively; additionally, it was found that the coefficient of friction between steel-alumina coatings is 0.36 and aluminium-alumina coating is 0.25.

  12. Improving the scratch resistance of sol-gel metal oxide coatings cured at 250 C through use of thermogenerated amines

    NARCIS (Netherlands)

    Langanke, J.; Arfsten, N.; Buskens, P.; Habets, R.; Klankermayer, J.; Leitner, W.

    2013-01-01

    Scratch resistant sol-gel metal oxide coatings typically require a thermal post-treatment step (curing process) at temperatures between 400 and 700 C. In this report, we demonstrate that the in situ generation of amines within sol-gel films facilitates the preparation of scratch resistant metal

  13. Study and development of refractory coatings for metallic uranium fusion and evaporation

    International Nuclear Information System (INIS)

    Vasconcelos, Getulio de

    2004-01-01

    In melting process or evaporation of metallic uranium, the reaction with the crucible and the possible contamination of the molten metal should be avoided. This effect can be reduced using an inert and protective coating on the crucible walls. The selection of the coating should be based on the chemical inertia and the kinetic of the reaction products. By avoiding chemical reactions, the amount of impurities in the molten metal can be reduced, leading to an increased crucible lifetime. This work presents a comparative study among different crucible coatings used in the melting process of metallic uranium, at temperatures above its melting point. Samples of metallic uranium are melted in contact with different materials in a vacuum furnace. The reactions occur at a given temperature during a certain time interval; samples are then cooled down to room temperature. Finally, samples are characterized by optical and electronic microscopy, dispersive X-ray spectroscopy, surface roughness and X-ray diffraction. Samples preparation consists of polishing selected areas, and milling the reaction products originated from the corroded interfaces. The extent of the reactions is determined as a function of the temperature by optical microscopy and roughness analyses. The compositions of the reacted products are determined by Energy Dispersive Spectroscopy, and the phase changes by X-ray diffraction. The results indicate that alumina presented higher activation energy (39 kcal.mol -1 ) than magnesia (12 kcal.mol -1 ), otherwise, it is corroded faster. On the other hand, the alumina could be protected by a thick coating of titanium nitride, because no rection between titanium nitride and uranium was observed at temperatures near to 1700 K. After cooling to the room temperature, there is stress concentration between the graphite and the TiN layer, generating a compressive stress of 0,5 GPa. When uranium is deposited on the TiN, a tensile stress is generated in this new layer, which

  14. Hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications

    Science.gov (United States)

    Seals, Roland D.

    2015-08-18

    The present disclosure relates generally to hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications. More specifically, the present disclosure relates to hardface coatings that include a network of titanium monoboride (TiB) needles or whiskers in a matrix, which are formed from titanium (Ti) and titanium diboride (TiB.sub.2) precursors by reactions enabled by the inherent energy provided by the process heat associated with coating deposition and, optionally, coating post-heat treatment. These hardface coatings are pyrophoric, thereby generating further reaction energy internally, and may be applied in a functionally graded manner. The hardface coatings may be deposited in the presence of a number of fluxing agents, beta stabilizers, densification aids, diffusional aids, and multimode particle size distributions to further enhance their performance characteristics.

  15. Yttria coating on quartz mould inner surface for fabrication of metal fuel slug using injection casting process

    International Nuclear Information System (INIS)

    Vinod, A.V.; Hemanth Kumar, S.; Manivannan, A.; Muralidaran, P.; Anthonysamy, S.; Sudha, R.

    2016-01-01

    Quartz moulds are used for casting metal alloy of U-Zr slugs by injection casting process. Ceramic (Y 2 O 3 ) coating on inner surface of the quartz mould is provided to avoid silica contamination in the fuel slugs during casting. Experiments were carried out to standardise the coating process and optimising various parameters such as particle size of Y 2 O 3 , choice of suitable binder, method for application of coating, drying and sintering at high temperature to ensure uniformity and strength of coating. Required Coating thickness of ∼40 μm was achieved on a quartz mould of inner diameter of 4.98±0.01mm. Experimental procedure for coating on inner surface of the quartz tubes using yttrium oxide is described in this work. (author)

  16. Sensitive resonant gas sensor operating in air with metal organic frameworks coating

    KAUST Repository

    Jaber, Nizar

    2017-08-09

    We report a practical resonant gas sensor that is uniformly coated with metal organic frameworks (MOFs) and excited near the higher order modes for a higher attained sensitivity. The resonator is based on an electrostatically excited clamped-clamped microbeam. The microbeam is fabricated from a polyimide layer coated from the top with Cr/Au and from the bottom with Cr/Au/Cr layer. The geometry of the resonator is optimized to reduce the effect of the squeeze film damping, thereby allowing operation under atmospheric pressure. The electrostatic force electrode is designed to enhance the excitation of the second mode of vibration with the minimum power required. Significant frequency shift (kHz) is demonstrated for the first time upon water vapor, acetone, and ethanol exposure due to the MOFs functionalization and the higher order modes excitation. Also, the adsorption dynamics and MOF selectivity is investigated by studying the decaying time constants of the response upon gas exposure.

  17. Elliptical metallic hollow fiber inner-coated with non-uniform dielectric layer.

    Science.gov (United States)

    Tang, Xiaoli; Yu, Zhuzheng; Tu, Xuecou; Chen, Jian; Argyros, Alexander; Kuhlmey, Boris T; Shi, Yiwei

    2015-08-24

    We report on the fabrication and characterization of an elliptical hollow fiber inner coated with a silver layer and a dielectric layer for polarization maintaining and low loss transmission of terahertz (THz) radiation. The primary purpose of adding the dielectric layer is to prevent the silver layer from oxidation. The thickness of the dielectric layer is non-uniform owing to the surface tension of the coating, which was initially applied as a liquid. Transmission loss and polarization maintenance are experimentally characterized. Effects of the dielectric layer on transmission properties are analyzed by comparing the fiber to Ag-only fiber. Results show that a dielectric layer with thickness less than λ/10 can effectively decreases the power distributed on the metal surface and thus can practically reduce loss resulting from roughness of the silver layer. Bending effects on transmission loss and polarization maintenance are also investigated.

  18. Electrical four-point probing of spherical metallic thin films coated onto micron sized polymer particles

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Sigurd R., E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no; Stokkeland, August Emil; Zhang, Zhiliang; He, Jianying, E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Kristiansen, Helge [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway); Njagi, John; Goia, Dan V. [Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5814 (United States); Redford, Keith [Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway)

    2016-07-25

    Micron-sized metal-coated polymer spheres are frequently used as filler particles in conductive composites for electronic interconnects. However, the intrinsic electrical resistivity of the spherical thin films has not been attainable due to deficiency in methods that eliminate the effect of contact resistance. In this work, a four-point probing method using vacuum compatible piezo-actuated micro robots was developed to directly investigate the electric properties of individual silver-coated spheres under real-time observation in a scanning electron microscope. Poly(methyl methacrylate) spheres with a diameter of 30 μm and four different film thicknesses (270 nm, 150 nm, 100 nm, and 60 nm) were investigated. By multiplying the experimental results with geometrical correction factors obtained using finite element models, the resistivities of the thin films were estimated for the four thicknesses. These were higher than the resistivity of bulk silver.

  19. Liquid phase diffusion bonding of A1070 by using metal formate coated Zn sheet

    Science.gov (United States)

    Ozawa, K.; Koyama, S.; shohji, I.

    2017-05-01

    Aluminium alloy have high strength and easily recycle due to its low melting point. Therefore, aluminium is widely used in the manufacturing of cars and electronic devices. In recent years, the most common way for bonding aluminium alloy is brazing and friction stir welding. However, brazing requires positional accuracy and results in the formation of voids by the flax residue. Moreover, aluminium is an excellent heat radiating and electricity conducting material; therefore, it is difficult to bond together using other bonding methods. Because of these limitations, liquid phase diffusion bonding is considered to the suitable method for bonding aluminium at low temperature and low bonding pressure. In this study, the effect of metal formate coating processing of zinc surface on the bond strength of the liquid phase diffusion bonded interface of A1070 has been investigated by SEM observation of the interfacial microstructures and fractured surfaces after tensile test. Liquid phase diffusion bonding was carried out under a nitrogen gas atmosphere at a bonding temperature of 673 K and 713 K and a bonding load of 6 MPa (bonding time: 15 min). As a result of the metal formate coating processing, a joint having the ultimate tensile strength of the base aluminium was provided. It is hypothesized that this is because metallic zinc is generated as a result of thermal decomposition of formate in the bonded interface at lower bonding temperatures.

  20. Micro-Capillary Coatings Based on Spiropyran Polymeric Brushes for Metal Ion Binding, Detection, and Release in Continuous Flow

    Directory of Open Access Journals (Sweden)

    Aishling Dunne

    2018-04-01

    Full Text Available Micro-capillaries, capable of light-regulated binding and qualitative detection of divalent metal ions in continuous flow, have been realised through functionalisation with spiropyran photochromic brush-type coatings. Upon irradiation with UV light, the coating switches from the passive non-binding spiropyran form to the active merocyanine form, which binds different divalent metal ions (Zn2+, Co2+, Cu2+, Ni2+, Cd2+, as they pass through the micro-capillary. Furthermore, the merocyanine visible absorbance spectrum changes upon metal ion binding, enabling the ion uptake to be detected optically. Irradiation with white light causes reversion of the merocyanine to the passive spiropyran form, with simultaneous release of the bound metal ion from the micro-capillary coating.

  1. Purcell effect for finite-length metal-coated and metal nanowires

    DEFF Research Database (Denmark)

    Filonenko, Konstantin V.; Willatzen, Morten; Bordo, Vladimir G.

    2014-01-01

    We investigate the modification (enhancement and suppression) of the spontaneous emission rate of a dipole emitter in two configurations: inside a finite-length semiconductor nanowire surrounded by bulk metal and in the vicinity of a finite metal nanowire. Our analysis is based on a first......-principle approach, which is reduced to a seminumeric one in the limit of large nanowire aspect ratios. The numerical calculations are carried out for an emitter in a GaAs nanowire embedded in Ag or Au and for that nearby an Ag or Au nanowire in vacuum or dielectric. We consider in detail the Purcell and β factors...

  2. Development of technique for air coating and nickel and copper metalization of solar cells

    Science.gov (United States)

    1982-01-01

    Solar cells were made with a variety of base metal screen printing inks applied over silicon nitride AR coating and copper electroplated. Fritted and fritless nickel and fritless tin base printing inks were evaluated. Conversion efficiencies as high as 9% were observed with fritted nickel ink contacts, however, curve shapes were generally poor, reflecting high series resistance. Problems encountered in addition to high series reistance included loss of adhesion of the nickel contacts during plating and poor adhesion, oxidation and inferior curve shapes with the tin base contacts.

  3. Magnetron deposition of metal-ceramic protective coatings on glasses of windows of space vehicles

    OpenAIRE

    Sergeev, Viktor Petrovich; Panin, Viktor Evgenyevich; Psakhie, Sergey Grigorievich; Chernyavskii, Alexandr; Svechkin, Valerii; Khristenko, Yurii; Kalashnikov, Mark Petrovich; Voronov, Andrei

    2014-01-01

    Transparent refractory metal-ceramic nanocomposite coatings with a high coefficient of elasticrecovery and microhardness on the basis of Ni/Si-Al-N are formed on a glass substrate by the pulse magnetron deposition method. The structure-phase states were investigated by TEM, SEM. It was established that the first layer consists of Ni nanograins with a fcc crystalline lattice, the second layer is two-phase: 5-10 nm nanocrystallites of the AlN phase with the hcp crystalline lattice in amorphous ...

  4. Finishes for Metals. Paintability of Galvanized Steel, Corrosion Resistance of Metallized Coatings.

    Science.gov (United States)

    Building Research Inst., Inc., Washington, DC.

    Two papers are presented. The first, "Report of the AISI Research Project on the Paintability of Galvanized Steel," was a project aimed at determining optimum procedures for painting bright-spangled galvanized sheet steel products using three classes of trade sales paints--metallic zinc-dust, portland cement-in-oil, and water base emulsion paints.…

  5. A review of the electrodeposition of metal matrix composite coatings by inclusion of particles in a metal layer: an established and diversifying technology

    OpenAIRE

    Walsh, F.C.; Ponce de Leon, Carlos

    2014-01-01

    Following a brief overview of their history, which dates back to the 1920s with marked developments during the 1960s and 1970s, the principles of composite coatings, achieved by including particles dispersed in a bath into a growing electrodeposited metal layer, are considered. The principles and role of electroplating compared to other techniques for realising such coatings, are considered. A good quality particle dispersion (often aided by a suitable type and concentration of surfactants) a...

  6. Photoemission from Low Work Function Coated Metal Surfaces A Comparison of Theory to Experiment

    CERN Document Server

    Jensen, Kevin; Moody, Nathan A

    2005-01-01

    The development of rugged and/or self rejuvenating photocathodes with high quantum efficiency (QE) using the longest wavelength drive laser is of paramount importance for RF photo-injectors for high power FELs and accelerators. We report on our program to develop advanced photocathodes and to develop and validate models of photoemission from coated metals to analyze experimental data,* provide emission models usable by beam simulation codes,** and project performance. The model accounts for the effects of laser heating, thermal evolution, surface conditions, laser parameters, and material characteristics, and predicts current distribution and QE. The photoemission and QE from metals and dispenser photocathodes is evaluated: the later introduces complications such as coverage non-uniformity and field enhancement. The performance of the models is compared to our experimental results for dispenser photocathodes and cesiated surfaces (e.g., tungsten, silver, etc.) in which the time-dependent models are shown to a...

  7. Highly stretchable and conductive fibers enabled by liquid metal dip-coating

    Science.gov (United States)

    Zhang, Qiang; Roach, Devin J.; Geng, Luchao; Chen, Haosen; Qi, H. Jerry; Fang, Daining

    2018-03-01

    Highly stretchable and conductive fibers have been fabricated by dip-coating of a layer of liquid metal (eutectic gallium indium, EGaIn) on printed silicone elastomer filaments. This fabrication method exploits a nanolayer of oxide skin that rapidly forms on the surface of EGaIn when exposed to air. Through dip-coating, the sticky nature of the oxide skin leads to the formation of a thin EGaIn coating (˜5 μm thick) on the originally nonconductive filaments and renders these fibers excellent conductivity. Electrical characterization shows that the fiber resistance increases moderately as the fiber elongates but always maintains conductivity even when stretched by 800%. Besides this, these fibers possess good cyclic electrical stability with little degradation after hundreds of stretching cycles, which makes them an excellent candidate for stretchable conductors. We then demonstrate a highly stretchable LED circuit as well as a conductive stretchable net that extends the 1D fibers into a 2D configuration. These examples demonstrate potential applications for topologically complex stretchable electronics.

  8. Infrared Thermography as a Non-destructive Testing Solution for Thermal Spray Metal Coatings

    Science.gov (United States)

    Santangelo, Paolo E.; Allesina, Giulio; Bolelli, Giovanni; Lusvarghi, Luca; Matikainen, Ville; Vuoristo, Petri

    2017-12-01

    In this work, an infrared (IR) thermographic procedure was evaluated as a non-destructive testing tool to detect damage in thermal spray metallic coatings. As model systems, polished HVOF- and HVAF-sprayed Fe-based layers deposited onto steel plates were employed. Damage by external-object impingement was simulated through a cyclic impact-test apparatus, which induced circumferential and radial cracks across all model systems, and interface cracks of different sizes in distinct samples. Damaged and undamaged plates were bulk-heated to above 100 °C using an IR lamp; their free-convection cooling was then recorded by an IR thermocamera. The intentionally induced defects were hardly detectable in IR thermograms, due to IR reflection and artificial "hot" spots induced by residuals of transfer material from the impacting counterbody. As a micrometer-thin layer of black paint was applied, surface emissivity got homogenized and any artifacts were effectively suppressed, so that failed coating areas clearly showed up as "cold spots." This effect was more apparent when large interface cracks occurred. Finite-element modeling proved the physical significance of the IR-thermography approach, showing that failed coating areas are cooled by surrounding air faster than they are heated by conduction from the hot substrate, which is due to the insulating effect of cracks.

  9. Ultrarobust Biochips with Metal-Organic Framework Coating for Point-of-Care Diagnosis.

    Science.gov (United States)

    Wang, Congzhou; Wang, Lu; Tadepalli, Sirimuvva; Morrissey, Jeremiah J; Kharasch, Evan D; Naik, Rajesh R; Singamaneni, Srikanth

    2018-02-23

    Most biosensors relying on antibodies as recognition elements fail in harsh environment conditions such as elevated temperatures, organic solvents, or proteases because of antibody denaturation, and require strict storage conditions with defined shelf life, thus limiting their applications in point-of-care and resource-limited settings. Here, a metal-organic framework (MOF) encapsulation is utilized to preserve the biofunctionality of antibodies conjugated to nanotransducers. This study investigates several parameters of MOF coating (including growth time, surface morphology, thickness, and precursor concentrations) that determine the preservation efficacy against different protein denaturing conditions in both dry and wet environments. A plasmonic biosensor based on gold nanorods as the nanotransducers is employed as a model biodiagnostic platform. The preservation efficacy attained through MOF encapsulation is compared to two other commonly employed materials (sucrose and silk fibroin). The results show that MOF coating outperforms sucrose and silk fibroin coatings under several harsh conditions including high temperature (80 °C), dimethylformamide, and protease solution, owing to complete encapsulation, stability in wet environment and ease of removal at point-of-use by the MOF. We believe this study will broaden the applicability of this universal approach for preserving different types of on-chip biodiagnostic reagents and biosensors/bioassays, thus extending the benefits of advanced diagnostic technologies in resource-limited settings.

  10. Development of Thermal Spraying and Coating Techniques by Using Thixotropic Slurries Including Metals and Ceramics Particles

    International Nuclear Information System (INIS)

    Kirihara, S; Tasaki, S; Itakura, Y

    2013-01-01

    Thermal nanoparticles coating and microlines patterning were newly developed as novel technologies to fabricate fine ceramics layers and geometrical intermetallics patterns for mechanical properties modulations of practical alloys substrates. Nanometer sized alumina particles were dispersed into acrylic liquid resins, and the obtained slurries were sputtered by using compressed air jet. The slurry mists could blow into the arc plasma with argon gas spraying. On stainless steels substrates, the fine surface layers with high wear resistance were formed. In cross sectional microstructures of the coated layers, micromater sized cracks or pores were not observed. Subsequently, pure aluminum particles were dispersed into photo solidified acrylic resins, and the slurry was spread on the stainless steel substrates by using a mechanical knife blade. On the substrates, microline patterns with self similar fractal structures were drawn and fixed by using scanning of an ultra violet laser beam. The patterned pure metal particles were heated by the argon arc plasma spray assisting, and the intermetallics or alloys phases with high hardness were created through reaction diffusions. Microstructures in the coated layers and the patterned lines were observed by using a scanning electron microscopy.

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

    Directory of Open Access Journals (Sweden)

    E. B. Chabina

    2014-01-01

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

  12. Anti-reflection coating design for metallic terahertz meta-materials

    Science.gov (United States)

    Pancaldi, Matteo; Freeman, Ryan; Hudl, Matthias; Hoffmann, Matthias C.; Urazhdin, Sergei; Vavassori, Paolo; Bonetti, Stefano

    2018-02-01

    We demonstrate a silicon-based, single-layer anti-reflection coating that suppresses the reflectivity of metals at near-infrared frequencies, enabling optical probing of nano-scale structures embedded in highly reflective surroundings. Our design does not affect the interaction of terahertz radiation with metallic structures that can be used to achieve terahertz near-field enhancement. We have verified the functionality of the design by calculating and measuring the reflectivity of both infrared and terahertz radiation from a silicon/gold double layer as a function of the silicon thickness. We have also fabricated the unit cell of a terahertz meta-material, a dipole antenna comprising two 20-nm thick extended gold plates separated by a 2 $\\mu$m gap, where the terahertz field is locally enhanced. We used the time-domain finite element method to demonstrate that such near-field enhancement is preserved in the presence of the anti-reflection coating. Finally, we performed magneto-optical Kerr effect measurements on a single 3-nm thick, 1-$\\mu$m wide magnetic wire placed in the gap of such a dipole antenna. The wire only occupies 2\\% of the area probed by the laser beam, but its magneto-optical response can be clearly detected. Our design paves the way for ultrafast time-resolved studies, using table-top femtosecond near-infrared lasers, of dynamics in nano-structures driven by strong terahertz radiation.

  13. Development and testing of a method for coating metallic wastes by thermosetting resins

    International Nuclear Information System (INIS)

    Tassigny, C. de

    1985-01-01

    Decommissioning of nuclear installations produces large-sized metallic components difficult to be compacted or to be inserted in the usual containers. The purpose of this study was to develop a coating procedure for low and medium activity wastes, in order to: - fix the contamination of the waste by a first appropriate layer; - protect this layer from mechanical shocks by a second thick layer; - reduce the diffusion of radionuclides. The study has proven the feasibility of depositing epoxy resins by electrostatic spraying in a nuclear environment on steel sub-strata with an efficiency higher than 95%; showing that it is possible to work in closed ventilated rooms without risk of clogging the filters. Two layers of epoxy resin are sufficient to fix contamination with a factor of 8600; their thickness (about 30 μm) nevertheless limits their use to this application. To reduce diffusion of radionuclides (Co-60 and Cs-137), polyurethane resins were chosen with which it is possible to obtain a thick coating in only a short time. Their properties of fixing the contamination, retaining of radionuclides and resistance to impact, have been assessed. First application of the procedure on a contaminated metallic bellow coming from dismantling of nuclear reactor, has been carried out

  14. Anti-reflection coating design for metallic terahertz meta-materials.

    Science.gov (United States)

    Pancaldi, Matteo; Freeman, Ryan; Hudl, Matthias; Hoffmann, Matthias C; Urazhdin, Sergei; Vavassori, Paolo; Bonetti, Stefano

    2018-02-05

    We demonstrate a silicon-based, single-layer anti-reflection coating that suppresses the reflectivity of metals at near-infrared frequencies, enabling optical probing of nano-scale structures embedded in highly reflective surroundings. Our design does not affect the interaction of terahertz radiation with metallic structures that can be used to achieve terahertz near-field enhancement. We have verified the functionality of the design by calculating and measuring the reflectivity of both infrared and terahertz radiation from a silicon/gold double layer as a function of the silicon thickness. We have also fabricated the unit cell of a terahertz meta-material, a dipole antenna comprising two 20-nm thick extended gold plates separated by a 2 μm gap, where the terahertz field is locally enhanced. We used the time-domain finite element method to demonstrate that such near-field enhancement is preserved in the presence of the anti-reflection coating. Finally, we performed magneto-optical Kerr effect measurements on a single 3-nm thick, 1-μm wide magnetic wire placed in the gap of such a dipole antenna. The wire only occupies 2% of the area probed by the laser beam, but its magneto-optical response can be clearly detected. Our design paves the way for ultrafast time-resolved studies, using table-top femtosecond near-infrared lasers, of dynamics in nano-structures driven by strong terahertz radiation.

  15. Evaluation of antimicrobial efficacy of nano coated silver-titania metallic plates against selective pathogens

    Directory of Open Access Journals (Sweden)

    Mohamad, S.M.

    2012-01-01

    Full Text Available Aim: Nanotechnology is an increasingly growing field with its current application in Science and Technology for the purpose of manufacture of novel materials at the nanoscale level. Silver-Titania nanoparticles (AgTiO2-NPs have been known to have inhibitory and bactericidal effects.Methodology and Results: In the present study, stable silver-titania nanoparticles coated metallic blocks were prepared for testing their efficacy against selected bacterial pathogens like Escherichia coli and Staphylococcus aureus. In the experimental part, the bacterial pathogens were inoculated on silver-titania nanoparticle coated blocks and the treatment was carried out in „0‟ time and „24‟ h interval and were enumerated.Conclusion, significance and impact of study:The results were compared with the control (uncoated metallic blocks and analyzed by using Japanese Industrial Standard (JIS Z2801:2000 method. From this study, it was concluded that silver-titania nanoparticles has inhibitory effect on bacterial pathogen tested.

  16. Optimizing the vacuum plasma spray deposition of metal, ceramic, and cermet coatings using designed experiments

    Science.gov (United States)

    Kingswell, R.; Scott, K. T.; Wassell, L. L.

    1993-06-01

    The vacuum plasma spray (VPS) deposition of metal, ceramic, and cermet coatings has been investigated using designed statistical experiments. Processing conditions that were considered likely to have a significant influence on the melting characteristics of the precursor powders and hence deposition efficiency were incorporated into full and fractional factorial experimental designs. The processing of an alumina powder was very sensitive to variations in the deposition conditions, particularly the injection velocity of the powder into the plasma flame, the plasma gas composition, and the power supplied to the gun. Using a combination of full and fractional factorial experimental designs, it was possible to rapidly identify the important spraying variables and adjust these to produce a deposition efficiency approaching 80 percent. The deposition of a nickel-base alloy metal powder was less sensitive to processing conditions. Generally, however, a high degree of particle melting was achieved for a wide range of spray conditions. Preliminary experiments performed using a tungsten carbide/cobalt cermet powder indicated that spray efficiency was not sensitive to deposition conditions. However, microstructural analysis revealed considerable variations in the degree of tungsten carbide dissolution. The structure and properties of the optimized coatings produced in the factorial experiments are also discussed.

  17. Citrate coated silver nanoparticles change heavy metal toxicities and bioaccumulation of Daphnia magna.

    Science.gov (United States)

    Kim, Injeong; Lee, Byung-Tae; Kim, Hyun-A; Kim, Kyoung-Woong; Kim, Sang Don; Hwang, Yu-Sik

    2016-01-01

    Citrate-coated AgNPs (c-AgNPs) have negatively charged surfaces and their surface interactions with heavy metals can affect metal toxicity in aquatic environments. This study used Daphnia magna to compare the acute toxicities and bioaccumulation of As(V), Cd, and Cu when they interact with c-AgNPs. The 24-h acute toxicities of As(V) and Cu were not affected by the addition of c-AgNPs, while bioaccumulation significantly decreased in the presence of c-AgNPs. In contrast, both the 24-h acute toxicity and bioaccumulation of Cd increased in the presence of c-AgNPs. These toxicity and bioaccumulation trends can be attributed to the interactions between the AgNP surface and the heavy metals. As(V) and c-AgNPs compete by negative charge, decreasing As(V) toxicity. Copper adheres readily to c-AgNP citrate, decreasing Cu bioavailability, and thus reducing Cu toxicity and bioaccumulation. Citrate complexes with divalent cations such as Ca and Mg reduce the competition between divalent cations and Cd on biotic ligand, increasing toxicity and bioaccumulation of Cd. This study shows that surface properties determine the effect of c-AgNPs on heavy metal toxicities and bioaccumulations; hence, further studies on the effect of nanoparticle by it surface properties are warranted. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Stabilization of metal nanoparticle films on glass surfaces using ultrathin silica coating.

    Science.gov (United States)

    Chaikin, Yulia; Kedem, Ofer; Raz, Jennifer; Vaskevich, Alexander; Rubinstein, Israel

    2013-11-05

    Metal nanoparticle (NP) films, prepared by adsorption of NPs from a colloidal solution onto a preconditioned solid substrate, usually form well-dispersed random NP monolayers on the surface. For certain metals (e.g., Au, Ag, Cu), the NP films display a characteristic localized surface plasmon resonance (LSPR) extinction band, conveniently measured using transmission or reflection ultraviolet-visible light (UV-vis) spectroscopy. The surface plasmon band wavelength, intensity, and shape are affected by (among other parameters) the NP spatial distribution on the surface and the effective refractive index (RI) of the surrounding medium. A major concern in the formation of such NP assemblies on surfaces is a commonly observed instability, i.e., a strong tendency of the NPs to undergo aggregation upon removal from the solution and drying, expressed as a drastic change in the LSPR band. Since various imaging modes and applications require dried NP films, preservation of the film initial (wet) morphology and optical properties upon drying are highly desirable. The latter is achieved in the present work by introducing a convenient and generally applicable method for preventing NP aggregation upon drying while preserving the original film morphology and optical response. Stabilization of Au and Ag NP monolayers toward drying is accomplished by coating the immobilized NPs with an ultrathin (3.0-3.5 nm) silica layer, deposited using a sol-gel reaction performed on an intermediate self-assembled aminosilane layer. The thin silica coating prevents NP aggregation and maintains the initial NP film morphology and LSPR response during several cycles of drying and immersion in water. It is shown that the silica-coated NP films retain their properties as effective LSPR transducers.

  19. Adhesive bond of veneering composites on various metal surfaces using silicoating, titanium-coating or functional monomers.

    Science.gov (United States)

    Behr, Michael; Rosentritt, Martin; Gröger, Gerhard; Handel, Gerhard

    2003-01-01

    This study compared the shear bond strength (SBS) between veneering composites and titanium (grade 1), a cobalt-chromium-alloy and a high precious-alloy, which were pretreated using silicoating systems, functional monomers or an experimental titanium-dioxide coating system. The specimens were sized to rectangular plates of 20 x10 x 2mm(3) (l,w,h) and a composite cylinder (height of 4mm, diameter 5mm) was axially polymerized to the middle of the plates. After aging (24h or 150 d storage in distilled water at 37 degrees C, or thermal-cycling: 6000 x 5 degrees /55 degrees C) the SBS was determined. Independent of the type of metal and the conditioning/coating techniques the lowest SBSs were found after thermal-cycling. Titanium. The SBS of the silica coating systems and the functional monomers did not differ statistically on titanium. However, the titanium-dioxide coating method had significantly higher values than the other methods. Cobalt-chromium. The highest mean values were observed with the titanium-dioxide coating system and the phosphate acid ester. Precious alloy. No statistical significant different SBS was found for the silicoating and the titanium-dioxide coating methods, while the functional monomers were statistically significant (lower) different to both systems. Generally, the titanium-dioxide coating system achieved the highest SBS under different aging conditions and on all three different metal-surfaces.

  20. High sensitive mesoporous TiO2-coated love wave device for heavy metal detection.

    Science.gov (United States)

    Gammoudi, I; Blanc, L; Moroté, F; Grauby-Heywang, C; Boissière, C; Kalfat, R; Rebière, D; Cohen-Bouhacina, T; Dejous, C

    2014-07-15

    This work deals with the design of a highly sensitive whole cell-based biosensor for heavy metal detection in liquid medium. The biosensor is constituted of a Love wave sensor coated with a polyelectrolyte multilayer (PEM). Escherichia coli bacteria are used as bioreceptors as their viscoelastic properties are influenced by toxic heavy metals. The acoustic sensor is constituted of a quartz substrate with interdigitated transducers and a SiO2 guiding layer. However, SiO2 shows some degradation when used in a saline medium. Mesoporous TiO2 presents good mechanical and chemical stability and offers a high active surface area. Then, the addition of a thin titania layer dip-coated onto the acoustic path of the sensor is proposed to overcome the silica degradation and to improve the mass effect sensitivity of the acoustic device. PEM and bacteria deposition, and heavy metal influence, are real time monitored through the resonance frequency variations of the acoustic device. The first polyelectrolyte layer is inserted through the titania mesoporosity, favouring rigid link of the PEM on the sensor and improving the device sensitivity. Also, the mesoporosity of surface increases the specific surface area which can be occupied and favors the formation of homogeneous PEM. It was found a frequency shift near -20±1 kHz for bacteria immobilization with titania film instead of -7±3 kHz with bare silica surface. The sensitivity is highlighted towards cadmium detection. Moreover, in this paper, particular attention is given to the immobilization of bacteria and to biosensor lifetime. Atomic Force Microscopy characterizations of the biosurface have been done for several weeks. They showed significant morphological differences depending on the bacterial life time. We noticed that the lifetime of the biosensor is longer in the case of using a mesoporous TiO2 layer. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Temperature dependence of W metallic coatings synthesized by double glow plasma surface alloying technology on CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Jie; Hei, Hongjun; Shen, Yanyan; Liu, Xiaoping; Tang, Bin; He, Zhiyong, E-mail: hezhiyong@tyut.edu.cn; Yu, Shengwang, E-mail: yushengwang@tyut.edu.cn

    2015-11-30

    Highlights: • DGPSA was firstly adopted to deposit W coatings on free-standing diamond films. • Temperature dependence of W coatings on free-standing diamond films was discussed. • W{sub 2}C and WC were formed at W/diamond interface during the DGPSA treatment. • The coatings possess continuous and compact surface structure except that made at 900 °C. • The coating obtained at 800 °C has the best adhesion and the maximum shear strength. - Abstract: W metallic coatings were synthesized on free-standing chemical vapor deposition (CVD) diamond films using double glow plasma surface alloying (DGPSA) technology. The influence of varying metalizing temperatures on the microstructures, phase composition and adhesion of the W metallic coatings were investigated. Likewise, the effectiveness of the W metallic coatings was preliminary evaluated via examining the shear strength of the brazing joints between W-metalized diamond films and commercial cemented carbide (WC–Co) inserts. The results showed that continuous and compact W metallic coatings were formed on the diamond films in the temperature range of 750–800 °C, while cracks or cavities presented at the W/diamond interface at 700 °C, 850 °C and 900 °C. Inter-diffusion of W and C atoms preformed, and WC and W{sub 2}C were formed at the W/diamond interfaces at all temperatures except 700 °C, at which only W{sub 2}C was formed. Moreover, etched cavities appeared at the W/diamond interface when the temperature exceeded 850 °C. The critical loads for coating delamination, as measured with the scratch test, increased as the temperature rose from 700 °C to 800 °C, while decreased with further increasing temperature. The maximum load was obtained at 800 °C with a value of 17.1 N. Besides, the shear strength of the brazing joints depicted the similar trend with the critical load. The highest shear strength (249 MPa) was also obtained at 800 °C.

  2. Post-Plasma SiOx Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications

    Science.gov (United States)

    Post, Patrick; Jidenko, Nicolas; Weber, Alfred P.; Borra, Jean-Pascal

    2016-01-01

    The plasma-based aerosol process developed for the direct coating of particles in gases with silicon oxide in a continuous chemical vapor deposition (CVD) process is presented. It is shown that non-thermal plasma filaments induced in a dielectric barrier discharge (DBD) at atmospheric pressure trigger post-DBD gas phase reactions. DBD operating conditions are first scanned to produce ozone and dinitrogen pentoxide. In the selected conditions, these plasma species react with gaseous tetraethyl orthosilicate (TEOS) precursor downstream of the DBD. The gaseous intermediates then condense on the surface of nanoparticles and self-reactions lead to homogeneous solid SiOx coatings, with thickness from nanometer to micrometer. This confirms the interest of post-DBD injection of the organo-silicon precursor to achieve stable production of actives species with subsequent controlled thickness of SiOx coatings. SiOx coatings of spherical and agglomerated metal and metal oxide nanoparticles (Pt, CuO, TiO2) are achieved. In the selected DBD operating conditions, the thickness of homogeneous nanometer sized coatings of spherical nanoparticles depends on the reaction duration and on the precursor concentration. For agglomerates, operating conditions can be tuned to cover preferentially the interparticle contact zones between primary particles, shifting the sintering of platinum agglomerates to much higher temperatures than the usual sintering temperature. Potential applications for enhanced thermal stability and tunable photoactivity of coated agglomerates are presented. PMID:28335219

  3. Evaluation of extractant-coated magnetic microparticles for the recovery of hazardous metals from waste solution

    International Nuclear Information System (INIS)

    Kaminski, M. D.

    1998-01-01

    A magnetically assisted chemical separation (MACS) process was developed earlier at Argonne National Laboratory (ANL). This compact process was designed for the separation of transuranics (TRU) and radionuclides from the liquid waste streams that exist at many DOE sites, with an overall reduction in waste volume requiring disposal. The MACS process combines the selectivity afforded by solvent extractant/ion exchange materials with magnetic separation to provide an efficient chemical separation. Recently, the MACS process has been evaluated with acidic organophosphorus extractants for hazardous metal recovery from waste solutions. Moreover, process scale-up design issues have been addressed with respect to particle filtration and recovery. Two acidic organophosphorus compounds have been investigated for hazardous metal recovery, bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanexreg-sign 272) and bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanexreg-sign 301). Coated onto magnetic microparticles, these extractants demonstrated superior recovery of hazardous metals from solution, relative to what was expected on the basis of results from solvent extraction experiments. The results illustrate the diverse applications of MACS technology for dilute waste streams. Preliminary process scale-up experiments with a high-gradient magnetic separator at Oak Ridge National Laboratory have revealed that very low microparticle loss rates are possible

  4. Metal-Free Carbon-Based Nanomaterial Coatings Protect Silicon Photoanodes in Solar Water-Splitting.

    Science.gov (United States)

    Yoon, KunHo; Lee, Jae-Hyeok; Kang, Joohoon; Kang, Junmo; Moody, Michael J; Hersam, Mark C; Lauhon, Lincoln J

    2016-12-14

    The decreasing cost of silicon-based photovoltaics has enabled significant increases in solar electricity generation worldwide. Silicon photoanodes could also play an important role in the cost-effective generation of solar fuels, but the most successful methods of photoelectrode passivation and performance enhancement rely on a combination of precious metals and sophisticated processing methods that offset the economic arguments for silicon. Here we show that metal-free carbon-based nanomaterial coatings deposited from solution can protect silicon photoanodes carrying out the oxygen evolution reaction in a range of working environments. Purified semiconducting carbon nanotubes (CNTs) act as a hole extraction layer, and a graphene (Gr) capping layer both protects the CNT film and acts as a hole exchange layer with the electrolyte. The performance of semiconducting CNTs is found to be superior to that of metallic or unsorted CNTs in this context. Furthermore, the insertion of graphene oxide (GO) between the n-Si and CNTs reduces the overpotential relative to photoanodes with CNTs deposited on hydrogen-passivated silicon. The composite photoanode structure of n-Si/GO/CNT/Gr shows promising performance for oxygen evolution and excellent potential for improvement by optimizing the catalytic properties and stability of the graphene protective layer.

  5. Transition Metal Coatings for Energy Conversion and Storage; Electrochemical and High Temperature Applications

    Science.gov (United States)

    Falola, Bamidele Daniel

    sequestration easier. One complication of oxyfuel coal combustion is that corrosion problems can be exacerbated due to flue gas recycling, which is employed to dilute the pure O2 feed and reduce the flame temperature. Refractory metal diffusion coatings of Ti and Zr atop P91 steel were created and tested for their ability to prevent corrosion in an oxidizing atmosphere at elevated temperature. Using pack cementation, diffusion coatings of thickness approximately 12 and 20 microm are obtained for Ti and Zr, respectively. The effects of heating to 950°C for 24 hr in 5% O2 in He are studied in situ by thermogravimetric analyses (TGA), and ex situ by SEM analyses and depth profiling by EDX. For Ti-coated, Zr-coated and uncoated P91 samples, extended heating in an oxidizing environment causes relatively thick oxide growth, but extensive oxygen penetration greater than 2.7 mm below the sample surface, and eventual oxide exfoliation, are observed only for the uncoated P91 sample. For the Ti- and Zr-coated samples, oxygen penetrates approximately 16 and 56 microm, respectively, below the surface. in situ TGA verifies that Ti-and Zr-coated P91 samples undergo far smaller mass changes during corrosion than uncoated samples, reaching close to steady state mass after approximately four hours.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  7. Field emission from entangled carbon nanotubes coated on/in a hollow metallic tube

    CERN Document Server

    Tokura, Y; Ohigashi, N; Akita, S; Nakayama, Y; Imasaki, K; Mima, K; Nakai, S

    2001-01-01

    Field emission properties of entangled carbon nanotubes were studied for an electron beam source of Cherenkov or Smith-Purcell free electron laser. The cathode was made of carbon nanotubes which were mixed with a very small amount of resin and coated on/in a hollow metallic tube with outer diameter of 0.5 mm. The emission current was as high as 2.2 mA with a fluctuation of <4%. It seems that some entangled nanotubes were frayed under the high electric field and then electrons were emitted mainly from their tips. Reduction of the work function of the carbon nanotubes was observed with the degradation of vacuum pressure in the experimental apparatus.

  8. Self-optimized metal coatings for fiber plasmonics by electroless deposition.

    Science.gov (United States)

    Bialiayeu, A; Caucheteur, C; Ahamad, N; Ianoul, A; Albert, J

    2011-09-26

    We present a novel method to prepare optimized metal coatings for infrared Surface Plasmon Resonance (SPR) sensors by electroless plating. We show that Tilted Fiber Bragg grating sensors can be used to monitor in real-time the growth of gold nano-films up to 70 nm in thickness and to stop the deposition of the gold at a thickness that maximizes the SPR (near 55 nm for sensors operating in the near infrared at wavelengths around 1550 nm). The deposited films are highly uniform around the fiber circumference and in spite of some nanoscale roughness (RMS surface roughness of 5.17 nm) the underlying gratings show high quality SPR responses in water. © 2011 Optical Society of America

  9. Interfacial reaction in cast WC particulate reinforced titanium metal matrix composites coating produced by laser processing

    Science.gov (United States)

    Liu, Dejian; Hu, Peipei; Min, Guoqing

    2015-06-01

    Laser injection of ceramic particle was conducted to produce particulate reinforced metal matrix composites (MMCs) coating on Ti-6Al-4V alloy. Cast WC particle (WCp) was used as injection reinforcement to avoid excessive release of carbon atoms into the melt pool. The interfaces and boundaries between WC and Ti matrix were investigated by electron microscopy study. Compared with single crystal WCp, cast WCp was an appropriate solution to control the reaction products (TiC) in the matrix and the total amount of reaction products was significantly reduced. Irregular-shape reaction layers were formed around cast WCp. The reaction layers consist of a W2C layer and a mixed layer of W and TiC. Such reaction layers are effective in load transfer under an external load.

  10. Ultrasensitive humidity detection using metal-organic framework-coated microsensors.

    Science.gov (United States)

    Robinson, Alex L; Stavila, Vitalie; Zeitler, Todd R; White, Michael I; Thornberg, Steven M; Greathouse, Jeffery A; Allendorf, Mark D

    2012-08-21

    The use of metal-organic framework (MOF) thin films to detect water vapor across a wide concentration range is demonstrated using MOF-functionalized quartz surface acoustic wave (SAW) sensors. A range of 3-14,800 ppmv was obtained with thin films of the MOF Cu(3)(benzenetricarboxylate)(2) (Cu-BTC) deposited by an automated layer-by-layer method. Devices coated by a manual technique demonstrated sensitivity from 0.28 to 14,800 ppmv, the limit of our test system. This exceeds the sensitivity of many commercially available sensors. Cu-BTC layers were covalently bonded directly to the silicon oxide surface, allowing devices to be heated beyond 100 °C to desorb water adsorbed in the pores without decomposition, thereby regenerating the sensors. Sensor response as a function of coating thickness was evaluated, showing that the SAW sensor response is bounded by maximum and minimum layer thicknesses. Computer simulation of H(2)O uptake shows a multistep adsorption isotherm defined by initial adsorption at open Cu-sites, followed by pore-filling and finally full saturation. Modeling and experimental results are consistent. Calculated uptake values suggest an efficient adsorption of H(2)O by Cu-BTC. These results provide the first convincing evidence that MOF functionalization of compact sensing technologies such as SAW devices and microcantilevers can compete with state-of-the art devices.

  11. Heavy metal concentration in coat hair and hoof horn in stabled and reserve Polish Konik horses.

    Science.gov (United States)

    Stachurska, A; Wałkuska, G; Chałabis-Mazurek, A; Jaworski, Z; Cebera, M

    2009-01-01

    The objective of the study was to determine if there were differences in Cr, Mn, Cu, Cd, Pb and Ni levels in coat hair and hoof horn between Polish Konik horses maintained in stabled and reserve systems in Roztocze National Park in Poland. Summer and winter feeding seasons (seasons of the year in case of hooves) and age of horses were taken into account. 107 samples of hair and hooves, as well as all kinds of feed and sources of water available for the horses were examined. The results of the study indicate that the concentration of the elements in the coat hair, hoof horn, feeds and water is usually too low to show possible influence of the system of maintenance in feeding seasons and age effect. The reserve horses are not more exposed to heavy metal contamination than the stabled horses. In the hair, solely Mn level is affected by the systems of maintenance in summer and winter feeding seasons: during winter it is higher, particularly in the stabled system, than during summer. In hooves, Cr concentration is higher in stabled horses than in reserve horses and conversely, Cu content is higher in the reserve horses. Mn content is age-affected both in hair and hooves, likewise is Cu content in the hooves. The results indicate a necessity of Cu compound supplementation in feeding the horses in both systems of maintenance.

  12. Smart Resonant Gas Sensor and Switch Operating in Air With Metal-Organic Frameworks Coating

    KAUST Repository

    Jaber, Nizar

    2017-11-03

    We report a resonant gas sensor, uniformly coated with a metal-organic framework (MOF), and excited it near the higher order modes for a higher attained sensitivity. Also, switching upon exceeding a threshold value is demonstrated by operating the resonator near the bifurcation point and the dynamic pull-in instabilities. The resonator is based on an electrostatically excited clamped-clamped microbeam. The microbeam is fabricated from a polyimide layer coated from the top with Cr/Au and from the bottom with Cr/Au/Cr layer. The geometry of the resonator is optimized to reduce the effect of squeeze film damping, thereby allowing operation under atmospheric pressure. The electrostatic electrode is designed to enhance the excitation of the second mode of vibration with the minimum power required. Significant frequency shift (kHz) is demonstrated for the first time upon water vapor, acetone, and ethanol exposure due to the MOF functionalization and the higher order modes excitation. Also, the adsorption dynamics and MOF selectivity is investigated by studying the decaying time constants of the response upon gas exposure.

  13. Deeply-etched micromirror with vertical slit and metallic coating enabling transmission-type optical MEMS filters

    Science.gov (United States)

    Othman, Muhammad A.; Sabry, Yasser M.; Sadek, Mohamed; Nassar, Ismail M.; Khalil, Diaa A.

    2016-03-01

    In this work we report a novel optical MEMS deeply-etched mirror with metallic coating and vertical slot, where the later allows reflection and transmission by the micromirror. The micromirror as well as fiber grooves are fabricated using deep reactive ion etching technology, where the optical axis is in-plane and the components are self-aligned. The etching depth is 150 μm chosen to improve the micromirror optical throughput. The vertical optical structure is Al metal coated using the shadow mask technique. A fiber-coupled Fabry-Pérot filter is successfully realized using the fabricated structure. Experimental measurements were obtained based on a dielectric-coated optical fiber inserted into a fiber groove facing the slotted micromirror. A versatile performance in terms of the free spectral range and 3-dB bandwidth is achieved.

  14. The Influence of Electrolytic Concentration on the Electrochemical Deposition of Calcium Phosphate Coating on a Direct Laser Metal Forming Surface

    Directory of Open Access Journals (Sweden)

    Qianyue Sun

    2017-01-01

    Full Text Available A calcium phosphate (CaP coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating’s morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy. In group 10−2, coatings were rich in dicalcium phosphate, characterized to be thick, layered, and disordered plates. In contrast, in groups 10−3 and 10−4, the relatively thin and well-ordered coatings predominantly consisted of granular hydroxyapatite. Further, the hydrophilicity and cell affinity were improved as electrolytic concentration increased. In particular, the cells cultured in group 10−3 appeared to have spindle morphology with thick pseudopodia on CaP coatings; these spindles and pseudopodia strongly adhered to the rough and porous surface. By analyzing and evaluating the surface properties, we provided further knowledge on the electrolytic concentration effect, which will be critical for improving CaP coated Ti implants in the future.

  15. The erosion performance of particle reinforced metal matrix composite coatings produced by co-deposition cold gas dynamic spraying

    Science.gov (United States)

    Peat, Tom; Galloway, Alexander; Toumpis, Athanasios; McNutt, Philip; Iqbal, Naveed

    2017-02-01

    This work reports on the erosion performance of three particle reinforced metal matrix composite coatings, co-deposited with an aluminium binder via cold-gas dynamic spraying. The deposition of ceramic particles is difficult to achieve with typical cold spray techniques due to the absence of particle deformation. This issue has been overcome in the present study by simultaneously spraying the reinforcing particles with a ductile metallic binder which has led to an increased level of ceramic/cermet particles deposited on the substrate with thick (>400 μm) coatings produced. The aim of this investigation was to evaluate the erosion performance of the co-deposited coatings within a slurry environment. The study also incorporated standard metallographic characterisation techniques to evaluate the distribution of reinforcing particles within the aluminium matrix. All coatings exhibited poorer erosion performance than the uncoated material, both in terms of volume loss and mass loss. The Al2O3 reinforced coating sustained the greatest amount of damage following exposure to the slurry and recorded the greatest volume loss (approx. 2.8 mm3) out of all of the examined coatings. Despite the poor erosion performance, the WC-CoCr reinforced coating demonstrated a considerable hardness increase over the as-received AA5083 (approx. 400%) and also exhibited the smallest free space length between adjacent particles. The findings of this study reveal that the removal of the AA5083 matrix by the impinging silicon carbide particles acts as the primary wear mechanism leading to the degradation of the coating. Analysis of the wear scar has demonstrated that the damage to the soft matrix alloy takes the form of ploughing and scoring which subsequently exposes carbide/oxide particles to the impinging slurry.

  16. Speciation study of the heavy metals in commercially available recharge cards coatings in Nigeria and the health implication

    Directory of Open Access Journals (Sweden)

    Abolanle S. Adekunle

    2014-01-01

    Full Text Available This work assessed levels of heavy metals exposure from silver coatings of mobile phones recharge cards of three major companies (designated as A, B and C with price denominations 100, 200 and 400 from companies A, B and C respectively, which were carefully scratched using a plastic scraper into a glass tube. The coatings were acid digested for total metal concentration, while speciation experiment for Mn, Cu, Cd and Pb was carried out. Total metals and speciation analysis were done using AAS and XRF techniques. The total metal concentration from XRF analysis was in the range: Ca (70–2140 μg/g, K (20–4930 μg/g, Sc (80–270 μg/g, Ti (1530–12,580 μg/g, Fe (50–6660 μg/g, Ni (20–2040 μg/g, Cu (20–850 μg/g and Zn (40–460 μg/g. Cr had the lowest concentration (10 μg/g in A (400 while Ti had the highest concentration (12,580 μg/g in C (500 for all the coatings analyzed. AAS and XRF results agreed closely except for Fe with higher concentration. A (100 contained high concentration of the metals compared with others. Speciation study identified Mn as the most mobile element when present in the environment.

  17. Surface modification of orthodontic implants by nanocomposite coatings based on chitosan and metals

    Directory of Open Access Journals (Sweden)

    Suetenkov D.Ye.

    2013-09-01

    Full Text Available Purpose: to study the properties of nanostructured coatings in orthodontic implants. Material and methods. Low and average molecular mass chitosan, 3-amynopropil-3-methoxysylan and suspensions of 5 nm and 10 nm gold nano-spheres stabilized with natrium citrate were used for nanocomposed surfaces. 2mg/ml polyethylenamin water solution was used for making the underlayer before putting polyion coverage using «POLYION-1M». The polyion covering dynamics was studied by polyquartz weighing method. Morphology of created layers was studied with atomic microscopy, elements were studied by secondary ion mass-spectrometry. Results. The best transmission among structures of chito-san/metals was showed by low molecular mass of chitosan and 8-1 Onm nanoparticles of metals. Analysis of roughness of surface shows that nanoparticles of gold make the most solid surface on 3-amynopropil-3-methoxysylan underlayer. Conclusion. The development of biocomparative materials in maxillofacial surgery is considered to be effective method of decreasing the risk of post-operative inflammatory complications by local antibacterial effect.

  18. Investigation of the structure and properties of a-C:H coatings with metal and silicon containing interlayers

    Science.gov (United States)

    Nöthe, M.; Breuer, U.; Koch, F.; Penkalla, H. J.; Rehbach, W. P.; Bolt, H.

    2001-07-01

    The structure of the interface of a-C:H coatings deposited with metal and Si-containing interlayers has been studied. Carbide forming metals (Al, Ti, Cr) can improve the chemical bonding compared with a substrate material which does not form carbides extensively by itself. In addition, a graded transition zone enlarges the interface between the carbon layer and the interlayer metal. In the present work the metal atoms were evaporated and ionized into a dense Ar plasma and deposited onto Si (100) substrates. A graded interface between the metal interlayer and the a-C:H coating was produced by introducing C 2H 2 with increasing amount into the Ar/He plasma during the PAPVD metal deposition process. The PACVD a-C:H deposition process was continued after the termination of metal evaporation to produce the pure a-C:H top layer. Further to Al-, Cr-, Ti- and Cu-interlayers, Si-containing interlayers were investigated. The Si-containing interlayers were deposited by a PACVD process using tetraethoxysilane Si(OC 2H 5) 4 (TEOS) and tetramethylsilane Si(CH 3) 4 (TMS). The characterization of the deposited layer systems was performed by SIMS, SNMS and XPS analyses as well as SEM and analytical TEM methods.

  19. Fabrication of Fiber Bragg Grating Coating with TiO2 Nanostructured Metal Oxide for Refractive Index Sensor

    Directory of Open Access Journals (Sweden)

    Shaymaa Riyadh Tahhan

    2017-01-01

    Full Text Available To increase the sensitivity of biosensor a new approach using an optical fiber Bragg grating (FBG coated with a suitable nanostructured metal oxide (NMO is proposed which is costly effective compared to other biosensors. Bragg grating was written on a D-shaped optical fiber by phase mask method using a 248 nm KrF excimer laser for a 5 min exposure time producing a grating with a period of 528 nm. Titanium dioxide (TiO2 nanostructured metal oxide was coated over the fiber for the purpose of increasing its sensing area. The etched D-shaped FBG was then coated with 312 nm thick TiO2 nanostructured layer to ensure propagating the radiation modes within the core. The final structure was used to sense deionized water and saline. The etched D-shaped FBG original sensitivity before coating to air-deionized water and to air-saline was 0.314 nm/riu and 0.142 nm/riu, respectively. After coating the sensitivity became 1.257 nm/riu for air-deionized water and 0.857 nm/riu for air-saline.

  20. Determination of the thermal conductivity of metallic coatings; Determinacion de la conductividad termica de recubrimientos metalicos

    Energy Technology Data Exchange (ETDEWEB)

    Uc Way, Manuel Eugenio

    1998-02-01

    Due to the corrosion by high temperature there is a serious problem of unavailability and efficiency of the steam generators in the thermoelectric power stations. One of the parts that is more affected by this phenomenon is the superheater tube banks. In order to diminish this problem it is intended to apply to these tubes a metallic coating nickel and chromium based (80Ni20Cr), the deposition of the coating is made by the method of thermal spraying of powders by flame. The coating thickness once it has been deposited is of the order of 500mm, it is doubtless that the thermal flow between gases of combustion and the fluid conducted in the tubes is affected. That is why it is important to know the thermal conductivity of the coating in order to evaluate the impact that it has in the operation of the steam generator. This necessity is the one that gives rise to the present thesis project, in which a technique that allows to measure the thermal conductivity of the coating is designed. The experimentation is carried out taking as departure point the ASTM norm E1225-87 and is adapted to the characteristics of the material to prove. A test piece of stainless steel 316 was designed to measure the thermal flow that traverses the coating. First the experimental installation was characterized in order to determine its reliability. Later the experimentation was made finding an average thermal conductivity of 2.09{+-}0.72 W/m K in the temperature interval of 110-180 Celsius degrees. This value is 12.3% inferior to the corresponding one of a solid metal of the same composition. If we consider that in the high temperature banks of the steam generators the thermal flow is in the interval from 15.000 to 100.000 W/m{sup 2} and a coating thickness of the order of 500mm it would cause that this material would introduce a temperature difference of 0.6 to 4 Celsius degrees, respectively. Please note that for the highest thermal flow a maximum affectation of 4 Celsuis degrees is

  1. Airborne Nanoparticle Release and Toxicological Risk from Metal-Oxide-Coated Textiles: Toward a Multiscale Safe-by-Design Approach.

    Science.gov (United States)

    Mantecca, Paride; Kasemets, Kaja; Deokar, Archana; Perelshtein, Ilana; Gedanken, Aharon; Bahk, Yeon Kyoung; Kianfar, Baharh; Wang, Jing

    2017-08-15

    Nano metal oxides have been proposed as alternatives to silver (Ag) nanoparticles (NPs) for antibacterial coatings. Here, cotton and polyester-cotton fabrics were sonochemically coated with zinc oxide (ZnO) and copper oxide (CuO) NPs. By varying the reaction solvent (water or ethanol), NPs with different sizes and shapes were synthesized. The cytotoxic and pro-inflammatory effects of studied NPs were investigated in vitro in human alveolar epithelial A549 and macrophage-like THP1 cells. To understand the potential respiratory impact of the NPs, the coated textiles were subjected to the abrasion tests, and the released airborne particles were measured. A very small amount of the studied metal oxides NPs was released from abrasion of the textiles coated by the ethanol-based sonochemical process. The release from the water-based coating was comparably higher. Lung and immune cells viability decreased after 24 h of exposure only at the highest studied NPs concentration (100 μg/mL). Different from the ZnO NPs, both formulations of CuO NPs induced IL-8 release in the lung epithelial cells already at subtoxic concentrations (1-10 μg/mL) but not in immune cells. All of the studied NPs did not induce IL-6 release by the lung and immune cells. Calculations revealed that the exposures of the NPs to human lung due to the abrasion of the textiles were lower or comparable to the minimum doses in the cell viability tests (0.1 μg/mL), at which acute cytotoxicity was not observed. The results alleviate the concerns regarding the potential risk of these metal oxide NPs in their applications for the textile coating and provide insight for the safe-by-design approach.

  2. Soluble salts: their incidence on the protection of metallic structures by paint coatings

    Directory of Open Access Journals (Sweden)

    Morcillo, M.

    2003-12-01

    Full Text Available The presence of soluble salts at the metal/paint interface is known to have a detrimental effect on the integrity of most paint systems. Though this is a long-standing problem, it has recently come to receive greater attention from the protective coatings industry. In the paper the following points are reviewed: degradation mechanisms of the metal/paint system, the role of the metallic substrate, the nature, origin and detection of soluble salts, expected levels of soluble salts in practice, critical thresholds of soluble salts and risk levels for premature failures, role of the type and thickness of paint systems and exposure conditions, and prevention measures. The author presents an overview of the subject, making reference to the related research that has been carried out by him and his coworkers over the last 16 years.

    Es un hecho conocido que la presencia de sales solubles en la intercara metal/pintura tiene un efecto negativo sobre la mayoría de los sistemas de pintura. Aunque se trata de un problema conocido desde hace tiempo, ha sido recientemente cuando ha recibido una gran atención por parte de la industria de recubrimientos protectores. En el presente trabajo se revisan los siguientes aspectos: mecanismos de degradación del sistema metal/pintura, el papel que juega el substrato metálico, la naturaleza, origen y detección de las sales solubles, niveles esperados de sales solubles en la práctica, niveles críticos de sales solubles y niveles de riesgo de fallo prematuro del sistema de pintura, papel que juega el tipo y espesor del sistema de pintura, el ambiente de exposición y las medidas de prevención. El autor presenta una revisión del tema, haciendo referencia a los trabajos de investigación que ha llevado a cabo, junto con su grupo de investigación, durante los últimos 16 años.

  3. The effect of metallic coatings and crystallinity on the volume expansion of silicon during electrochemical lithiation/delithiation

    KAUST Repository

    McDowell, Matthew T.

    2012-05-01

    Applying surface coatings to alloying anodes for Li-ion batteries can improve rate capability and cycle life, but it is unclear how this second phase affects mechanical deformation during electrochemical reaction. Here, in-situ transmission electron microscopy is employed to investigate the electrochemical lithiation and delithiation of silicon nanowires (NWs) with copper coatings. When copper is coated on only one sidewall, the NW bilayer structure bends during delithiation due to length changes in the silicon. Tensile hoop stress causes conformal copper coatings to fracture during lithiation without undergoing bending deformation. In addition, in-situ and ex-situ observations indicate that a copper coating plays a role in suppressing volume expansion during lithiation. Finally, the deformation characteristics and dimensional changes of amorphous, polycrystalline, and single-crystalline silicon are compared and related to observed electrochemical behavior. This study reveals important aspects of the deformation process of silicon anodes, and the results suggest that metallic coatings can be used to improve rate behavior and to manage or direct volume expansion in optimized silicon anode frameworks. © 2012 Elsevier Ltd.

  4. Treatment of heavy metals by iron oxide coated and natural gravel media in Sustainable urban Drainage Systems.

    Science.gov (United States)

    Norris, M J; Pulford, I D; Haynes, H; Dorea, C C; Phoenix, V R

    2013-01-01

    Sustainable urban Drainage Systems (SuDS) filter drains are simple, low-cost systems utilized as a first defence to treat road runoff by employing biogeochemical processes to reduce pollutants. However, the mechanisms involved in pollution attenuation are poorly understood. This work aims to develop a better understanding of these mechanisms to facilitate improved SuDS design. Since heavy metals are a large fraction of pollution in road runoff, this study aimed to enhance heavy metal removal of filter drain gravel with an iron oxide mineral amendment to increase surface area for heavy metal scavenging. Experiments showed that amendment-coated and uncoated (control) gravel removed similar quantities of heavy metals. Moreover, when normalized to surface area, iron oxide coated gravels (IOCGs) showed poorer metal removal capacities than uncoated gravel. Inspection of the uncoated microgabbro gravel indicated that clay particulates on the surface (a natural product of weathering of this material) augmented heavy metal removal, generating metal sequestration capacities that were competitive compared with IOCGs. Furthermore, when the weathered surface was scrubbed and removed, metal removal capacities were reduced by 20%. When compared with other lithologies, adsorption of heavy metals by microgabbro was 10-70% higher, indicating that both the lithology of the gravel, and the presence of a weathered surface, considerably influence its ability to immobilize heavy metals. These results contradict previous assumptions which suggest that gravel lithology is not a significant factor in SuDS design. Based upon these results, weathered microgabbro is suggested to be an ideal lithology for use in SuDS.

  5. Microwave sintering of poly-ether-ether-ketone (PEEK) based coatings deposited on metallic substrate

    International Nuclear Information System (INIS)

    Zhang, G.; Leparoux, S.; Liao, H.; Coddet, C.

    2006-01-01

    In this paper, the feasibility of microwave (MW) sintering PEEK (poly-ether-ether-ketone) based coatings was investigated. Three coatings were studied: pure PEEK, micron-SiC and nano-SiC particles filled (wt.10%) PEEK coatings. The results indicate that, for the two composite coatings, the SiC particles distributed in the polymer matrix, as a good MW susceptor, could be heated preferentially by MW radiation. Consequently, the polymer matrix was heated by these particles

  6. Structure-property relationship of ceramic coatings on metals produced by laser processing

    NARCIS (Netherlands)

    de Hosson, J.T.M.; van den Burg, M.; Mazumder, J; Conde, O; Villar, R; Steen, W

    1996-01-01

    This paper concentrates on the mechanical performance of various ceramic coatings of Cr2O3 on steel (SAF2205), as produced by CO2 laser processing. The thickness of the coating that can be applied by laser coating is limited to about 200 mu m setting a limit to the maximum strain energy release rate

  7. Electrochemical behavior of polypyrrole/chitosan composite coating on Ti metal for biomedical applications.

    Science.gov (United States)

    Rikhari, Bhavana; Pugal Mani, S; Rajendran, N

    2018-06-01

    In the present work, the corrosion resistance performance and biocompatibility of polypyrrole/chitosan (PPy/CHI) composite coated Ti was studied. The deposition of composite coating was carried out by electropolymerization method. The deposited PPy/CHI composite coatings were different in morphology, structural, surface roughness and wettability compared PPy coated Ti. The presence of composite coating was confirmed by solid 13 C NMR. The PPy/CHI composite coating showed enhanced microhardness and adhesion strength compared to the PPy coating. The corrosion protection ability of PPy/CHI composite coatings at various applied potentials was analyzed by dynamic electrochemical impedance spectroscopy (DEIS), exhibited higher impedance in all the potentials compared to uncoated and PPy coated Ti. The lower corrosion current density obtained for PPy/CHI-2 composite coating from polarization studies revealed increased corrosion protection ability in SBF solution. The stability of composite coating was confirmed by immersion studies. PPy/CHI-2 composite coating immersed in SBF solution enhances hydroxyapatite (HAp) formation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Coated metal stents installation for the treatment of malignant tumors complicated with colonic and rectal fistula

    International Nuclear Information System (INIS)

    Mao Aiwu; Fang Shiming; Liu Shiyi; Lin Qing; Jiang Haosheng; Jia Yiping; Gao Zhongdu

    2007-01-01

    Objective: To probe the clinical features of malignant colonic and rectal tumors together with coated metal stent placement. Methods: 24 cases of colonic fistula with late stage malignant tumors including 16 cases of intestinal cancer(66.7%), 2 cases of gastric and cervical cancers respectively(8.3%); 1 case of bladder, 1 case of prostate, 1 case of ovary and 1 case of gallbladder cancer(4.2%). The cause for the fistulas were direct invasion (37.5% )and radiotherapy (62.5%). The KPS was 30-60, and the median value was 40. CT were done preoperatively and followed by radiography of canulation contrast medium enema to ensure the location of the orifice of the fistula, the route of intestinal canal or complicated with obstruction and the condition with nearby tissues. Stents were finally implanted specifically according to the different situations of intestines. The sites of implanted stents and the occlusion of fistula should be strictly scrutinized; and then with careful follow up of patients complications and general condition. The procedure was carried out practically in 23 cases. Results: The successful rate of technique reached 96%(22/23), the failed one was due to the curve over sharpness of intestinal lock and resulting in non-expansion of the stent. The clinical successful rate was 91.3%. The two failed cased included the one with improper coherence to the intestinal wall leading to the stent migration and the other with a mild leakage after stent placement. The follow-up duration were 28-365 days, average 109 days, and the median value was 92 days. The average surviving period of 3 months and 6 months were 51% and 11% respectively. Conclusion: Intestinal fistula is the common complication after intestinal tumor operation and radiotherapy with poor prognosis. Metal covered stents provide a therapy of choice to improve the life quality and prolong the life span. (authors)

  9. Effects of silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets

    Directory of Open Access Journals (Sweden)

    Saadet Atsü

    2011-06-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effects of tribochemical silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets. MATERIAL AND METHODS: Twenty debonded metal and 20 debonded ceramic brackets were randomly assigned to receive one of the following surface treatments (n=10 for each group: (1 sandblasting (control; (2 tribochemical silica coating combined with silane. Brackets were rebonded to the enamel surface on the labial and lingual sides of premolars with a light-polymerized resin composite. All specimens were stored in distilled water for 1 week and then thermocycled (5,000 cycles between 5-55ºC. Shear bond strength values were measured using a universal testing machine. Student's t-test was used to compare the data (α=0.05. Failure mode was assessed using a stereomicroscope, and the treated and non-treated bracket surfaces were observed by scanning electron microscopy. RESULTS: Rebonded ceramic brackets treated with silica coating followed by silanization had significantly greater bond strength values (17.7±4.4 MPa than the sandblasting group (2.4±0.8 MPa, P<0.001. No significant difference was observed between the rebonded metal brackets treated with silica coating with silanization (15±3.9 MPa and the sandblasted brackets (13.6±3.9 MPa. Treated rebonded ceramic specimens primarily exhibited cohesive failure in resin and adhesive failure at the enamel-adhesive interface. CONCLUSIONS: In comparison to sandblasting, silica coating with aluminum trioxide particles followed by silanization resulted in higher bond strengths of rebonded ceramic brackets.

  10. Nuclear reactor pressure vessel with an inner metal coating covered with a high temperature resistant thermal insulator

    International Nuclear Information System (INIS)

    1974-01-01

    The thermal insulator covering the metal coating of a reactor vessel is designed for resisting high temperatures. It comprises one or several porous layers of ceramic fibers or of stacked metal foils, covered with a layer of bricks or ceramic tiles. The latter are fixed in position by fasteners comprising pins fixed to the coating and passing through said porous layers and fasteners (nut or bolts) for individually fixing the bricks to said pins, whereas ceramic plugs mounted on said bricks or tiles provide for the thermal insulation of the pins and of the nuts or bolts; such a thermal insulation can be applied to high-temperature reactors or to fast reactors [fr

  11. Study of the corrosion of metallic coatings and alloys containing aluminum in a mixed atmosphere - sulphur, oxygen - at high temperatures

    International Nuclear Information System (INIS)

    Fellmann, Daniel

    1982-01-01

    The objective of this research thesis is the development of materials for a sulphur experimental loop allowing the thermodynamic properties of such an energy cycle to be checked. As solutions must comply with industrial methods, rare materials are excluded as they are too expensive or difficult to implement. Iron-based materials have been tested but could not have at the same time a good corrosion resistance and high temperature forming and mechanical toughness properties. Therefore, metallic coatings have been chosen, specifically alumina. After having reported a bibliographical study on corrosion by sulphur vapour and by oxygen and by sulphur-oxygen, the author presents the experimental materials and methods. Then, the author reports the study of mixed corrosion (by sulphur and oxygen together) of metallic alloys (ferritic and austeno-ferritic alloys, aluminium and titanium alloys), and of the corrosion of FeAlx coatings, of AlTix alloys [fr

  12. Metal-Organic Frameworks (MOFs) as Sandwich Coating Cushion for Silicon Anode in Lithium Ion Batteries.

    Science.gov (United States)

    Han, Yuzhen; Qi, Pengfei; Zhou, Junwen; Feng, Xiao; Li, Siwu; Fu, Xiaotao; Zhao, Jingshu; Yu, Danni; Wang, Bo

    2015-12-09

    A novel metal-organic framework (MOF) sandwich coating method (denoted as MOF-SC) is developed for hybrid Li ion battery electrode preparation, in which the MOF films are casted on the surface of a silicon layer and sandwiched between the active silicon and the separator. The obtained electrodes show improved cycling performance. The areal capacity of the cheap and readily available microsized Si treated with MOF-SC can reach 1700 μAh cm(-2) at 265 μA cm(-2) and maintain at 850 μAh cm(-2) after 50 cycles. Beyond the above, the commercial nanosized Si treated by MOF-SC also shows greatly enhanced areal capacity and outstanding cycle stability, 600 μAh cm(-2) for 100 cycles without any apparent fading. By virtue of the novel structure prepared by the MOFs, this new MOF-SC structure serves as an efficient protection cushion for the drastic volume change of silicon during charge/discharge cycles. Furthermore, this MOF layer, with large pore volume and high surface area, can adsorb electrolyte and allow faster diffusion of Li(+) as evidenced by decreased impedance and improved rate performance.

  13. Research on width control of Metal Fused-coating Additive Manufacturing based on active control

    Science.gov (United States)

    Ren, Chuan qi; Wei, Zheng ying; Wang, Xin; Du, Jun; Zhang, Shan; Zhang, Zhitong; Bai, Hao

    2017-12-01

    Given the stability of the shape of the forming layer is one of the key problems that affect the final quality of the sample morphology, taking a study on the forming process and the control method of morphology make a significant difference to metal fused-coating additive manufacturing (MFCAM) in achieving the efficient and stable forming. To improve the quality and precision of the samples of single-layer single pass, a control method of morphology based on active control was established by this paper. The real-time acquisition of image was realized by CCD and the characteristics of morphology of the forming process were simultaneously extracted. Making analysis of the characteristics of the width during the process, the relationship between the relative difference of different frames and moving speed was given. A large number of experiments are used to verify the response speed and accuracy of the system. The results show that the active system can improve the morphology of the sample and the smoothness of the width of the single channel, and increase the uniformity of width by 55.16%.

  14. Investigation of Some Transparent Metal Oxides as Damp Heat Protective Coating for CIGS Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F. J.; Yan, F.; Zaaunbrecher, B.; To, B.; Perkins, J.; Noufi, R.

    2012-10-01

    We investigated the protective effectiveness of some transparent metal oxides (TMO) on CIGS solar cell coupons against damp heat (DH) exposure at 85oC and 85% relative humidity (RH). Sputter-deposited bilayer ZnO (BZO) with up to 0.5-um Al-doped ZnO (AZO) layer and 0.2-um bilayer InZnO were used as 'inherent' part of device structure on CdS/CIGS/Mo/SLG. Sputter-deposited 0.2-um ZnSnO and atomic layer deposited (ALD) 0.1-um Al2O3 were used as overcoat on typical BZO/CdS/CIGS/Mo/SLG solar cells. The results were all negative -- all TMO-coated CIGS cells exhibited substantial degradation in DH. Combining the optical photographs, PL and EL imaging, SEM surface micro-morphology, coupled with XRD, I-V and QE measurements, the causes of the device degradations are attributed to hydrolytic corrosion, flaking, micro-cracking, and delamination induced by the DH moisture. Mechanical stress and decrease in crystallinity (grain size effect) could be additional degrading factors for thicker AZO grown on CdS/CIGS.

  15. Titanium addition influences antibacterial activity of bioactive glass coatings on metallic implants

    Directory of Open Access Journals (Sweden)

    Omar Rodriguez

    2017-10-01

    Full Text Available In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy confirmed the release of zinc ions (Zn2+, which has been linked to the antibacterial abilities of glasses SRT0, BRT0 and BRT3, with inhibition effectively achieved at concentrations lower than 0.7 ppm. In vitro cytotoxicity studies using MC3T3-E1 osteoblasts confirmed that cell proliferation was affected by all glasses in this study, with decreased proliferation attributed to a faster release of sodium ions over calcium ions in both glass series, factor known to slow cell proliferation in vitro. Keywords: Biomedical engineering, Materials science

  16. Investigation of some transparent metal oxides as damp heat protective coating for CIGS solar cells

    Science.gov (United States)

    Pern, F. J.; Yan, F.; Zaunbrecher, K.; To, B.; Perkins, J.; Noufi, R.

    2012-10-01

    We investigated the protective effectiveness of some transparent metal oxides (TMO) on CIGS solar cell coupons against damp heat (DH) exposure at 85°C and 85% relative humidity (RH). Sputter-deposited bilayer ZnO (BZO) with up to 0.5- μm Al-doped ZnO (AZO) layer and 0.2-μm bilayer InZnO were used as "inherent" part of device structure on CdS/CIGS/Mo/SLG. Sputter-deposited 0.2-μm ZnSnO and atomic layer deposited (ALD) 0.1-μm Al2O3 were used as overcoat on typical BZO/CdS/CIGS/Mo/SLG solar cells. The results were all negative - all TMO-coated CIGS cells exhibited substantial degradation in DH. Combining the optical photographs, PL and EL imaging, SEM surface micromorphology, coupled with XRD, I-V and QE measurements, the causes of the device degradations are attributed to hydrolytic corrosion, flaking, micro-cracking, and delamination induced by the DH moisture. Mechanical stress and decrease in crystallinity (grain size effect) could be additional degrading factors for thicker AZO grown on CdS/CIGS.

  17. Plasma-Sprayed LSM Protective Coating on Metallic Interconnect of SOFC

    Directory of Open Access Journals (Sweden)

    Jia-Wei Chen

    2017-12-01

    Full Text Available In this study, a (La0.8Sr0.20.98MnO3 protective layer was prepared on the C276, Crofer22 APU, SUS304, and SUS430 alloys by the atmospheric plasma spraying technique (APS. The oxidation behavior and electrical property of these metal alloys have been investigated isothermally at 800 °C in air for up to 300 h. Results showed that the ferritic steels transform into MnCr2O4 spinels and a Cr2O3 layer during isothermal oxidation. The C276 alloy formed NiCr2O4 and FeCr2O4 layers; these are protective and act as an effective barrier against chromium migration into the outer oxide layer, and the alloy demonstrated good oxidation resistance and a reasonable match to the coefficient of thermal expansion of the substrate and a low-oxide scale area-specific resistance. The ASR effects on the formation of oxide scale have been investigated, and the ASR of coated samples was below 0.024 Ω·cm2. It has good electrical conductivity for SOFC in long-term use.

  18. Development of membrane filters with nanostructured porous layer by coating of metal nanoparticles sintered onto a micro-filter

    International Nuclear Information System (INIS)

    Park, Seok Joo; Park, Young Ok; Lee, Dong Geun; Ryu, Jeong In

    2008-01-01

    The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 KPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%

  19. Characterization of the electrochemical behavior of coating by steel welding 308l and in presence of noble metals deposits

    International Nuclear Information System (INIS)

    Piedras, P.; Arganis J, C. R.

    2014-10-01

    In this work the oxide deposits and noble metals deposit were characterized (Ag and Pt) on a coating of stainless steel 308l that were deposited by the shield metal arc welding (SMAW) on steel A36 by means of scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. The extrapolation of Tafel technique was also used to obtain the corrosion potential (Ec) for the pre-rusty steel and for the samples with deposits of Pt and Ag under conditions of hydrogen water chemistry (HWC), demonstrating that this parameter diminishes with the presence of this deposits. (Author)

  20. Transition Metal Ion Implantation into Diamond-Like Carbon Coatings: Development of a Base Material for Gas Sensing Applications

    Directory of Open Access Journals (Sweden)

    Andreas Markwitz

    2015-01-01

    Full Text Available Micrometre thick diamond-like carbon (DLC coatings produced by direct ion deposition were implanted with 30 keV Ar+ and transition metal ions in the lower percentage (<10 at.% range. Theoretical calculations showed that the ions are implanted just beneath the surface, which was confirmed with RBS measurements. Atomic force microscope scans revealed that the surface roughness increases when implanted with Ar+ and Cu+ ions, whereas a smoothing of the surface from 5.2 to 2.7 nm and a grain size reduction from 175 to 93 nm are measured for Ag+ implanted coatings with a fluence of 1.24×1016 at. cm−2. Calculated hydrogen and carbon depth profiles showed surprisingly significant changes in concentrations in the near-surface region of the DLC coatings, particularly when implanted with Ag+ ions. Hydrogen accumulates up to 32 at.% and the minimum of the carbon distribution is shifted towards the surface which may be the cause of the surface smoothing effect. The ion implantations caused an increase in electrical conductivity of the DLC coatings, which is important for the development of solid-state gas sensors based on DLC coatings.

  1. Control of exposure to hexavalent chromium concentration in shielded metal arc welding fumes by nano-coating of electrodes.

    Science.gov (United States)

    Sivapirakasam, S P; Mohan, Sreejith; Santhosh Kumar, M C; Thomas Paul, Ashley; Surianarayanan, M

    2018-02-20

    Background Cr(VI) is a suspected human carcinogen formed as a by-product of stainless steel welding. Nano-alumina and nano-titania coating of electrodes reduced the welding fume levels. Objective To investigate the effect of nano-coating of welding electrodes on Cr(VI) formation rate (Cr(VI) FR) from a shielded metal arc welding process. Methods The core welding wires were coated with nano-alumina and nano-titania using the sol-gel dip coating technique. Bead-on plate welds were deposited on SS 316 LN plates kept inside a fume test chamber. Cr(VI) analysis was done using an atomic absorption spectrometer (AAS). Results A reduction of 40% and 76%, respectively, in the Cr(VI) FR was observed from nano-alumina and nano-titania coated electrodes. Increase in the fume level decreased the Cr(VI) FR. Discussion Increase in fume levels blocked the UV radiation responsible for the formation of ozone thereby preventing the formation of Cr(VI).

  2. Plasma surface oxidation of 316L stainless steel for improving adhesion strength of silicone rubber coating to metal substrate

    Energy Technology Data Exchange (ETDEWEB)

    Latifi, Afrooz, E-mail: afroozlatifi@yahoo.com [Department of Biomaterials, Biomedical Engineering Faculty, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Imani, Mohammad [Novel Drug Delivery Systems Dept., Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of); Khorasani, Mohammad Taghi [Biomaterials Dept., Iran Polymer and Petrochemical Institute, P.O. Box 14965/159, Tehran (Iran, Islamic Republic of); Daliri Joupari, Morteza [Animal and Marine Biotechnology Dept., National Institute of Genetic Engineering and Biotechnology, P.O. Box 14965/161, Tehran (Iran, Islamic Republic of)

    2014-11-30

    Highlights: • Stainless steel 316L was surface modified by plasma surface oxidation (PSO) and silicone rubber (SR) coating. • On the PSO substrates, concentration of oxide species was increased ca. 2.5 times comparing to non-PSO substrates. • The surface wettability was improved to 12.5°, in terms of water contact angle, after PSO. • Adhesion strength of SR coating on the PSO substrates was improved by more than two times comparing to non-PSO ones. • After pull-off test, the fractured area patterns for SR coating were dependent on the type of surface modifications received. - Abstract: Stainless steel 316L is one of the most widely used materials for fabricating of biomedical devices hence, improving its surface properties is still of great interest and challenging in biomaterial sciences. Plasma oxidation, in comparison to the conventional chemical or mechanical methods, is one of the most efficient methods recently used for surface treatment of biomaterials. Here, stainless steel specimens were surface oxidized by radio-frequency plasma irradiation operating at 34 MHz under pure oxygen atmosphere. Surface chemical composition of the samples was significantly changed after plasma oxidation by appearance of the chromium and iron oxides on the plasma-oxidized surface. A wettable surface, possessing high surface energy (83.19 mN m{sup −1}), was observed after plasma oxidation. Upon completion of the surface modification process, silicone rubber was spray coated on the plasma-treated stainless steel surface. Morphology of the silicone rubber coating was investigated by scanning electron microscopy (SEM). A uniform coating was formed on the oxidized surface with no delamination at polymer–metal interface. Pull-off tests showed the lowest adhesion strength of coating to substrate (0.12 MPa) for untreated specimens and the highest (0.89 MPa) for plasma-oxidized ones.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S., E-mail: skumar@arci.res.in; Rao, A. Arjuna

    2017-02-28

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

  4. Ni catalyst wash-coated on metal monolith with enhanced heat-transfer capability for steam reforming

    Science.gov (United States)

    Ryu, Jae-Hong; Lee, Kwan-Young; La, Howon; Kim, Hak-Joo; Yang, Jung-Il; Jung, Heon

    A commercial Ni-based catalyst is wash-coated on a monolith made of 50 μm-thick fecralloy plates. Compared with the same volume of coarsely powdered Ni catalysts, the monolith wash-coated Ni catalysts give higher methane conversion in the steam reforming reaction, especially at gas hourly space velocities (GHSV) higher than 28,000 h -1, and with no pressure drop. A higher conversion of the monolith catalyst is obtained, even though it contains a lower amount of active catalyst (3 g versus 17 g for a powdered catalyst), which indicates that the heat-transfer capability of the wash-coated Ni catalyst is significantly enhanced by the use of a metal monolith. The efficacy of the monolith catalyst is tested using a shell-and-tube type heat-exchanger reactor with 912 cm 3 of the monolith catalyst charged on to the tube side and hot combusted gas supplied to the shell side in a counter-current direction to the reactant flow. A methane conversion greater than 94% is obtained at a GHSV of 7300 h -1 and an average temperature of 640 °C. Nickel catalysts should first be reduced to become active for steam reforming. Doping a small amount (0.12 wt.%) of noble metal (Ru or Pt) in the commercial Ni catalyst renders the wash-coated catalyst as active as a pre-reduced Ni catalyst. Thus, noble metal-doped Ni appears useful for steam reforming without any pre-reduction procedure.

  5. Development of coatings for ultrasonic additive manufacturing sonotrode using laser direct metal deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Niyanth S, Niyanth [ORNL; Dehoff, Ryan R [ORNL; Jordan, Brian H [ORNL; Babu, Sudarsanam Suresh [ORNL

    2016-10-01

    ORNL partnered with Fabrisonic, LLC to develop galling resistant hard facing coatings on sonotrodes used to fabricate 3D printed materials using ultrasonic additive manufacturing. The development and deployment of a coated sonotrode is expected to push the existing state of the art to facilitate the solidstate additive manufacturing of hard steels and titanium alloys. To this effect a structurally amorphous stainless steel material and cobalt chrome material were deposited on the sonotrode material. Both the deposits showed good adhesion to the substrate. The coatings made using the structurally amorphous steel materials showed cracking during the initial trials and cracking was eliminated by deposition on a preheated substrate. Both the coatings show hardness in excess of 600 HVN. Thus the phase 1 of this project has been used to identify suitable materials to use to coat the sonotrode. Despite the fact that successful deposits were obtained, the coatings need to be evaluated by performing detailed galling tests at various temperatures. In addition field tests are also necessary to test the stability of these coatings in a high cycle ultrasonic vibration mode. If awarded, phase 2 of the project would be used to optimize the composition of the deposit material to maximize galling resistance. The industrial partner would then use the coated sonotrode to fabricate builds made of austenitic stainless steel to test the viability of using a coated sonotrode.

  6. Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid by metal-oxide-coated Ti electrodes.

    Science.gov (United States)

    Maharana, Dusmant; Xu, Zesheng; Niu, Junfeng; Rao, Neti Nageswara

    2015-10-01

    Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) over metal-oxide-coated Ti anodes, i.e., Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2, was examined. The degradation efficiency of over 90% was attained at 20 min at different initial concentrations (0.5-20 mg L(-1)) and initial pH values (3.1-11.2). The degradation efficiencies of 2,4,5-T on Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2 anodes were higher than 99.9%, 97.2% and 91.5% at 30 min, respectively, and the respective total organic carbon removal ratios were 65.7%, 54.6% and 37.2%. The electrochemical degradation of 2,4,5-T in aqueous solution followed pseudo-first-order kinetics. The compounds, i.e., 2,5-dichlorohydroquinone and 2,5-dihydroxy-p-benzoquinone, have been identified as the main aromatic intermediates by liquid chromatography-mass spectrometry. The results showed that the energy efficiencies of 2,4,5-T (20 mg L(-1)) degradation with Ti/SnO2-Sb/Ce-PbO2 anode at the optimal current densities from 2 to 16 mA cm(-2) ranged from 8.21 to 18.73 kWh m(-3). Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Kinetics of the development of a nonchromate conversion coating for magnesium alloys and magnesium-based metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Nunez, M.A.; Skeldon, P.; Thompson, G.E.; Karimzadeh, H.

    1999-12-01

    Kinetics of the development of a conversion coating from a stannate bath on commercial purity magnesium (Mg{sup comm}), magnesium-based alloys ZC71 and WE43, and a metal matrix composite (MMC), comprising a ZC71 alloy matrix and 12 vol% silicon carbide (SiC) particles were studied using linear polarization resistance, potential-time, potentiodynamic polarization, x-ray diffraction, Rutherford backscattering spectroscopy, and microscopic examination. The coating, typically {approximately}3 {micro}m to 5 {micro}m thick, was composed largely of crystalline magnesium tin oxide (MgSnO{sub 3} {center{underscore}dot} 3H{sub 2}O), and developed by a nucleation and growth process through an initial corrosion film on the substrate. Nucleation probably occurred on regions where a critical concentration of magnesium ions was reached for coating crystals to form. Specific sites of nucleation, such as particles of eutectic phase and of reinforcement, were revealed in some cases, but frequently the precise sites of nucleation were not disclosed. A longer treatment time (at least 35 min) was suggested by polarization resistance data for improved coverage of the substrate than the previously recommended time of 20 min. The coating continuity on the substrates, after a particular time of treatment, depends upon ally composition increasing in order: Mg{sup comm}, 12% (SiC)p/ZC71 alloy MMC, ZC71 alloy, and WE43 alloy. Polarization resistance (R{sub p}) changed systematically with coating development, showing a decrease in R{sub p} in the early stages of the coating process, related to the initial corrosion.

  8. Performance characterization of metallic substrates coated by HVOF WC–Co

    International Nuclear Information System (INIS)

    Venter, Andrew M.; Oladijo, O. Philip; Luzin, Vladimir; Cornish, Lesley A.; Sacks, Natasha

    2013-01-01

    Integral to the performance of high-velocity oxygen-fuel (HVOF) coatings is the thermo-mechanical interaction associated with the thermal misfit, or differences in thermal expansion coefficients (CTEs), between coating and substrate. This investigation reports results on the microstructures, chemical phase content, coating–substrate misfit residual stress, and wear resistance. For this purpose a systematic characterization of WC–Co sprayed coatings on a number of substrates covering a range of CTE values were pursued for both the as-coated and heat-treated conditions. The neutron diffraction technique in conjunction with sub-millimeter sized gauge volumes enabled depth-resolved studies of the stress in the coatings and substrates by paying special attention to the determination of the stress contribution attributed by the final spray process. In the as-coated condition the stress values in the coatings were compressive for CTEs larger than that of WC–Co and tensile for CTE lower than WC–Co. Wear resistance increased for increased compressive stress and macrohardness. In the heat-treated condition, this trend became enhanced due to increased compressive stress in the coatings. - Highlights: • Four different substrate systems coated with HVOF WC-Co has been investigated. • Each substrate set encompassed the grit-blast surface and as-coated conditions, as well as their heat-treated counterparts. • Microstructural, macrohardness, wear performance and depth-resolved residual stress characterised. • Successful application of neutron strain scanning to investigating the combined systems, coatings and substrates. • Link observed between macrohardness, residual stress and wear performance

  9. Performance characterization of metallic substrates coated by HVOF WC–Co

    Energy Technology Data Exchange (ETDEWEB)

    Venter, Andrew M., E-mail: andrew.venter@necsa.co.za [Research and Development Division, Necsa Limited, Pretoria (South Africa); School of Chemical and Metallurgical Engineering, University of the Witwatersrand (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand (South Africa); Oladijo, O. Philip [School of Chemical and Metallurgical Engineering, University of the Witwatersrand (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand (South Africa); Luzin, Vladimir [ANSTO (Australian Nuclear Science and Technology Organisation), Lucas Height (Australia); Cornish, Lesley A.; Sacks, Natasha [School of Chemical and Metallurgical Engineering, University of the Witwatersrand (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand (South Africa)

    2013-12-31

    Integral to the performance of high-velocity oxygen-fuel (HVOF) coatings is the thermo-mechanical interaction associated with the thermal misfit, or differences in thermal expansion coefficients (CTEs), between coating and substrate. This investigation reports results on the microstructures, chemical phase content, coating–substrate misfit residual stress, and wear resistance. For this purpose a systematic characterization of WC–Co sprayed coatings on a number of substrates covering a range of CTE values were pursued for both the as-coated and heat-treated conditions. The neutron diffraction technique in conjunction with sub-millimeter sized gauge volumes enabled depth-resolved studies of the stress in the coatings and substrates by paying special attention to the determination of the stress contribution attributed by the final spray process. In the as-coated condition the stress values in the coatings were compressive for CTEs larger than that of WC–Co and tensile for CTE lower than WC–Co. Wear resistance increased for increased compressive stress and macrohardness. In the heat-treated condition, this trend became enhanced due to increased compressive stress in the coatings. - Highlights: • Four different substrate systems coated with HVOF WC-Co has been investigated. • Each substrate set encompassed the grit-blast surface and as-coated conditions, as well as their heat-treated counterparts. • Microstructural, macrohardness, wear performance and depth-resolved residual stress characterised. • Successful application of neutron strain scanning to investigating the combined systems, coatings and substrates. • Link observed between macrohardness, residual stress and wear performance.

  10. Antimicrobial and anti-biofilm properties of polypropylene meshes coated with metal-containing DLC thin films.

    Science.gov (United States)

    Cazalini, Elisa M; Miyakawa, Walter; Teodoro, Guilherme R; Sobrinho, Argemiro S S; Matieli, José E; Massi, Marcos; Koga-Ito, Cristiane Y

    2017-06-01

    A promising strategy to reduce nosocomial infections related to prosthetic meshes is the prevention of microbial colonization. To this aim, prosthetic meshes coated with antimicrobial thin films are proposed. Commercial polypropylene meshes were coated with metal-containing diamond-like carbon (Me-DLC) thin films by the magnetron sputtering technique. Several dissimilar metals (silver, cobalt, indium, tungsten, tin, aluminum, chromium, zinc, manganese, tantalum, and titanium) were tested and compositional analyses of each Me-DLC were performed by Rutherford backscattering spectrometry. Antimicrobial activities of the films against five microbial species (Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis) were also investigated by a modified Kirby-Bauer test. Results showed that films containing silver and cobalt have inhibited the growth of all microbial species. Tungsten-DLC, tin-DLC, aluminum-DLC, zinc-DLC, manganese-DLC, and tantalum-DLC inhibited the growth of some strains, while chromium- and titanium-DLC weakly inhibited the growth of only one tested strain. In-DLC film showed no antimicrobial activity. The effects of tungsten-DLC and cobalt-DLC on Pseudomonas aeruginosa biofilm formation were also assessed. Tungsten-DLC was able to significantly reduce biofilm formation. Overall, the experimental results in the present study have shown new approaches to coating polymeric biomaterials aiming antimicrobial effect.

  11. Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates.

    Science.gov (United States)

    Zhang, Martin Yi; Ye, Chang; Erasquin, Uriel Joseph; Huynh, Toan; Cai, Chengzhi; Cheng, Gary J

    2011-02-01

    In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells.

  12. Photo-Curable Metal-Chelating Coatings Offer a Scalable Approach to Production of Antioxidant Active Packaging.

    Science.gov (United States)

    Lin, Zhuangsheng; Goddard, Julie

    2018-02-01

    Synthetic metal chelators (for example, ethylenediaminetetraacetic acid, EDTA) are widely used as additives to control trace transition metal induced oxidation in consumer products. To enable removal of synthetic chelators in response to increasing consumer demand for clean label products, metal-chelating active food packaging technologies have been developed with demonstrated antioxidant efficacy in simulated food systems. However, prior work in fabrication of metal-chelating materials leveraged batch chemical reactions to tether metal-chelating ligands, a process with limited industrial translatability for large-scale fabrication. To improve the industrial translatability, we have designed a 2-step laminated photo-grafting process to introduce metal chelating functionality onto common polymeric packaging materials. Iminodiacetic acid (IDA) functionalized materials were fabricated by photo-grafting poly(acrylic acid) onto polypropylene (PP) films, followed by a second photo-grafting process to graft-polymerize an IDA functionalized vinyl monomer (GMA-IDA). The photo-grafting was conducted under atmospheric conditions and was completed in 2 min. The resulting IDA functionalized metal-chelating material was able to chelate iron and copper, and showed antioxidant efficacy against ascorbic acid degradation, supporting its potential to be used synergistically with natural antioxidants for preservation of food and beverage products. The 2-step photo-grafting process improves the throughput of active packaging coatings, enabling potential roll-to-roll fabrication of metal-chelating active packaging materials for antioxidant food packaging applications. To address consumer and retail demands for "clean label" foods and beverages without a corresponding loss in product quality and shelf life, producers are seeking next generation technologies such as active packaging. In this work, we will report the synthesis of metal-chelating active packaging films, which enable removal

  13. Plasma surface oxidation of 316L stainless steel for improving adhesion strength of silicone rubber coating to metal substrate

    Science.gov (United States)

    Latifi, Afrooz; Imani, Mohammad; Khorasani, Mohammad Taghi; Daliri Joupari, Morteza

    2014-11-01

    Stainless steel 316L is one of the most widely used materials for fabricating of biomedical devices hence, improving its surface properties is still of great interest and challenging in biomaterial sciences. Plasma oxidation, in comparison to the conventional chemical or mechanical methods, is one of the most efficient methods recently used for surface treatment of biomaterials. Here, stainless steel specimens were surface oxidized by radio-frequency plasma irradiation operating at 34 MHz under pure oxygen atmosphere. Surface chemical composition of the samples was significantly changed after plasma oxidation by appearance of the chromium and iron oxides on the plasma-oxidized surface. A wettable surface, possessing high surface energy (83.19 mN m-1), was observed after plasma oxidation. Upon completion of the surface modification process, silicone rubber was spray coated on the plasma-treated stainless steel surface. Morphology of the silicone rubber coating was investigated by scanning electron microscopy (SEM). A uniform coating was formed on the oxidized surface with no delamination at polymer-metal interface. Pull-off tests showed the lowest adhesion strength of coating to substrate (0.12 MPa) for untreated specimens and the highest (0.89 MPa) for plasma-oxidized ones.

  14. Graphitization of diamond with a metallic coating on ferritic matrix; Grafitizacao do diamante com revestimento metalico em matriz ferritica

    Energy Technology Data Exchange (ETDEWEB)

    Cabral, Stenio Cavalier; Oliveira, Hellen Cristine Prata de; Filgueira, Marcello, E-mail: stenio@uenf.b [Universidade Estadual do Norte Fluminense (PPGECM/CCT/UENF), Campos dos Goytacazes, RJ (Brazil). Centro de Ciencias e Tecnologia. Programa de Pos Graduacao em Engenharia e Ciencia dos Materiais

    2010-07-01

    Iron is a strong catalyst of graphitization of diamonds. This graphitization occurs mainly during the processing of composites - conventional sintering or hot pressing, and during cutting operations. Aiming to avoid or minimize this deleterious effect, there is increasing use of diamond coated with metallic materials in the production of diamond tools processed via powder metallurgy. This work studies the influence of Fe on diamond graphitization diamond-coated Ti after mixing of Fe-diamonds, hot pressing parameters were performed with 3 minutes/35MPa/900 deg C - this is the condition of pressing hot used in industry for production of diamond tools. Microstructural features were observed by SEM, diffusion of Fe in diamond was studied by EDS. Graphitization was analyzed by X-ray diffraction and Raman spectroscopy. It was found that Fe not activate graphitization on the diamond under the conditions of hot pressing. (author)

  15. Sputtering an exterior metal coating on copper enclosure for large-scale growth of single-crystalline graphene

    DEFF Research Database (Denmark)

    Luo, Birong; Caridad, José M; Whelan, Patrick Rebsdorf

    2017-01-01

    We show the suppression of nucleation density in chemical vapor deposited graphene through the use of a sputtered metal coating on the exterior of a copper catalyst enclosure, resulting in the growth of sub-centimeter scale single crystal graphene domains and complete elimination of multilayer...... growth. The sputtered coating suppresses nucleation density by acting as both a diffusion barrier and as a sink for excess carbon during the growth, reducing the carbon concentration in the interior of the enclosure. Field effect mobility of hBN-templated devices fabricated from graphene domains grown...... in this way show room temperature carrier mobilities of 12 000 cm2 V−1 s−1 and an absence of weak localization at low temperature. These results indicate a very low concentration of line and point defects in the grown films, which is further supported by Raman and transmission electron microscopic...

  16. Hierarchically structured manganese oxide-coated magnetic nanocomposites for the efficient removal of heavy metal ions from aqueous systems.

    Science.gov (United States)

    Kim, Eun-Ju; Lee, Chung-Seop; Chang, Yoon-Young; Chang, Yoon-Seok

    2013-10-09

    In this study, hierarchical MnO2-coated magnetic nanocomposite (Fe3O4/MnO2) was synthesized by a mild hydrothermal process, and its application for removing heavy metal ions from contaminated water systems was examined. Structural characterization showed that the Fe3O4 nanoparticle core was coated with amorphous MnO2 shell with flowerlike morphology. The as-prepared nanocomposite had a large surface area and high magnetic saturation value, which ensured its good sorption ability and convenience of separation. Fe3O4/MnO2 exhibited a greatly improved removal capacity toward four different heavy metals (Cd(II), Cu(II), Pb(II), and Zn(II)) compared to unmodified Fe3O4 nanoparticles. The adsorption property of Fe3O4/MnO2 was studied with Cd(II) in more detail. The sorption equilibrium data were well fitted to the Langmuir model, and the maximum adsorption capacity toward Cd(II) was 53.2 mg g(-1). Fe3O4/MnO2 retained over 80% of its adsorption capacity under various solution conditions that are typically encountered in natural waters. This nanocomposite was easily recovered and reused through consecutive adsorption-desorption experiments with the assistance of an external magnetic field. Overall, the findings propose that Fe3O4/MnO2 could be used as an effective recyclable adsorbent for heavy metal ions.

  17. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings

    International Nuclear Information System (INIS)

    Farmer, J C; Haslam, J J; Wong, F; Ji, X; Day, S D; Branagan, D J; Marshall, M C; Meacham, B E; Buffa, E J; Blue, C A; Rivard, J K; Beardsley, M B; Weaver, D T; Aprigliano, L F; Kohler, L; Bayles, R; Lemieux, E J; Wolejsza, T M; Martin, F J; Yang, N; Lucadamo, G; Perepezko, J H; Hildal, K; Kaufman, L; Heuer, A H; Ernst, F; Michal, G M; Kahn, H; Lavernia, E J

    2004-01-01

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an ''integral drip shield'' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent

  18. Fracture resistance of dental nickel-titanium rotary instruments with novel surface treatment: Thin film metallic glass coating.

    Science.gov (United States)

    Chi, Chih-Wen; Deng, Yu-Lun; Lee, Jyh-Wei; Lin, Chun-Pin

    2017-05-01

    Dental nickel-titanium (NiTi) rotary instruments are widely used in endodontic therapy because they are efficient with a higher success rate. However, an unpredictable fracture of instruments may happen due to the surface characteristics of imperfection (or irregularity). This study assessed whether a novel surface treatment could increase fatigue fracture resistance of dental NiTi rotary instruments. A 200- or 500-nm thick Ti-zirconium-boron (Ti-Zr-B) thin film metallic glass was deposited on ProTaper Universal F2 files using a physical vapor deposition process. The characteristics of coating were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. In cyclic fatigue tests, the files were performed in a simulated root canal (radius=5 mm, angulation=60°) under a rotating speed of 300rpm. The fatigue fractured cross sections of the files were analyzed with their fractographic performances through scanning electron microscopy images. The amorphous structure of the Ti-Zr-B coating was confirmed by transmission electron microscopy and X-ray diffractometry. The surface of treated files presented smooth morphologies without grinding irregularity. For the 200- and 500-nm surface treatment groups, the coated files exhibited higher resistance of cyclic fatigue than untreated files. In fractographic analysis, treated files showed significantly larger crack-initiation zone; however, no significant differences in the areas of fatigue propagation and catastrophic fracture were found compared to untreated files. The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure. Copyright © 2016. Published by Elsevier B.V.

  19. Metal monitoring for process control of laser-based coating removal

    Science.gov (United States)

    Fraser, Mark E.; Hunter, Amy J.; Panagiotou, Thomai; Davis, Steven J.; Freiwald, David A.

    1999-12-01

    Cost-effective and environmentally-sound means of paint and coatings removal is a problem spanning many government, commercial, industrial and municipal applications. For example, the Department of Energy is currently engaged in removing paint and other coatings from concrete and structural steel as part of decommissioning former nuclear processing facilities. Laser-based coatings removal is an attractive new technology for these applications as it promises to reduce the waste volume by up to 75 percent. To function more efficiently, however, the laser-based systems require some form of process control.

  20. Investigation of the interfacial condition between bioceramic coatings and metallic substrates using guided waves

    Science.gov (United States)

    Saffari, Nader; Ong, Chuon-Szen

    2001-04-01

    The work reported here is on the characterization of the interfacial properties between plasma-sprayed Hydroxyapatite coatings on titanium substrates as used in cement-less hip orthopaedic implants. The phase velocity dispersion for the first Rayleigh-type mode for the coating-substrate system has been shown to be sensitive to the interfacial stiffness. Different interfacial conditions between the coating and substrate have been obtained by cyclic loading of the specimens in a four-point bend fatigue machine. The measured interfacial stiffness is then correlated with the interfacial fracture strength obtained by standard destructive shear tests.

  1. Gold coated metal nanostructures grown by glancing angle deposition and pulsed electroplating

    Science.gov (United States)

    Grüner, Christoph; Reeck, Pascal; Jacobs, Paul-Philipp; Liedtke, Susann; Lotnyk, Andriy; Rauschenbach, Bernd

    2018-05-01

    Nickel based nanostructures are grown by glancing angle deposition (GLAD) on flat and pre-patterned substrates. These fabricated porous thin films were subsequently coated by pulsed electroplating with gold. The morphology and conformity of the gold coating were investigated by scanning electron microscopy and X-ray diffraction. Controlled growth of closed gold layers on the nanostructures could be achieved, while the open-pore structure of the nanosculptured thin films was preserved. Such gold coated nanostructures are a candidate for optical sensing and catalysis applications. The demonstrated method can be applied for numerous material combinations, allowing to provide GLAD thin films with new surface properties.

  2. Sliding properties of plasma assisted CVD CNchi coatings for metal bioimplants.

    Science.gov (United States)

    Konvickova, S; Cerny, F; Gurovic, J; Kvasnicka, I; Suchanek, J; Hnatowicz, V

    2000-01-01

    Coatings of CNchi, have been prepared on the substrates of material Ti6Al4V, of which the human joint replacements are made. The deposition of the CNchi coating was carried out by PACVD method in apparatus with standard arrangement. The methane and nitrogen have been used as precursors for CNchi compound. The infrared absorption spectroscopy and Rutherford backscattering spectroscopy were applied on diagnostics of prepared CNchi layer. Beside carbon and nitrogen the hydrogen and oxygen were found in the coatings. The sliding tests were carried out with the samples. The counter parts were the cylinders made of the polyethylene of the same type as for big joint prostheses is used. The tests were carried out in the medium of physiological solution. The CNchi coatings perform well under the lower load of 25 and 50 N. When the load is increased to 100 N, the friction coefficient slowly increases, but measured values of mu are typical for boundary lubrication.

  3. Evaluation of Hydrogen Cracking in Weld Metal Deposited using Cellulosic-Coated Electrodes

    Science.gov (United States)

    2009-06-16

    Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for "stovepipe" welding of pipelines because they are well suited for deposition of pipeline girth welds and are capable of high deposition rates when welding downhill. De...

  4. Removal of dissolved heavy metals from pre-settled stormwater runoff by iron-oxide coated sand (IOCS)

    DEFF Research Database (Denmark)

    Møller, J.; Ledin, Anna; Mikkelsen, Peter Steen

    2002-01-01

    Sorption to iron-oxide coated sand (IOCS) is a promosing technology for removal of the dissolved heavy metal fraction in stormwater runoff. The development of a new technology is necessary since studies of stormwater runoff from traffic areas indicate that an oil separator and detention pond may...... by IOCS after 480 pore volumes. Control columns with uncoated filter sand show that lead, copper and zinc were removed with >95%, 35% and 5%, respectively. The removal of the negative metaloxy-ion, CrO4-3 was insignificant in both IOCS and sand columns at pH=7.7. Destruction of the columns after...

  5. Pulsed-voltage atom probe tomography of low conductivity and insulator materials by application of ultrathin metallic coating on nanoscale specimen geometry.

    Science.gov (United States)

    Adineh, Vahid R; Marceau, Ross K W; Chen, Yu; Si, Kae J; Velkov, Tony; Cheng, Wenlong; Li, Jian; Fu, Jing

    2017-10-01

    We present a novel approach for analysis of low-conductivity and insulating materials with conventional pulsed-voltage atom probe tomography (APT), by incorporating an ultrathin metallic coating on focused ion beam prepared needle-shaped specimens. Finite element electrostatic simulations of coated atom probe specimens were performed, which suggest remarkable improvement in uniform voltage distribution and subsequent field evaporation of the insulated samples with a metallic coating of approximately 10nm thickness. Using design of experiment technique, an experimental investigation was performed to study physical vapor deposition coating of needle specimens with end tip radii less than 100nm. The final geometries of the coated APT specimens were characterized with high-resolution scanning electron microscopy and transmission electron microscopy, and an empirical model was proposed to determine the optimal coating thickness for a given specimen size. The optimal coating strategy was applied to APT specimens of resin embedded Au nanospheres. Results demonstrate that the optimal coating strategy allows unique pulsed-voltage atom probe analysis and 3D imaging of biological and insulated samples. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    2017-09-01

    demonstrated, the flame-sprayed polyole- fin coating is too costly for use on large steel structures. Guidance docu- ments are identified to help make...the feedstock material, the thermal-spray process and application parameters, and the post-treat- ment of the applied coating. An 85% zinc and 15...thickness (85/15 plus topcoat) was measured by gauge for compliance with project requirements. Total thickness measure- ments indicated that the

  7. Vanadium Alloyed PVD CrAlN Coatings for Friction Reduction in Metal Forming Applications

    Directory of Open Access Journals (Sweden)

    K. Bobzin

    2012-06-01

    Full Text Available Hard coatings deposited on forming tools are used to improve the forming process and to increase tool life. The decrease of tool wear and reduction of friction are the main motivations for the development of self-lubricating coatings for forming applications at elevated temperatures. In the present study (Cr,Al,VN (Physical Vapour Deposition coatings with 5, 11 and 20 at % vanadium were deposited via a combination of HPPMS (High Power Pulse Magnetron Sputtering technology and direct current (DC Magnetron Sputter Ion Plating (MSIP PVD. The hardness and Young’s Modulus of the coatings were investigated by nanoidentation. Furthermore, high temperature Pin-on-Disk (PoD tribometer measurements against Ck15 (AISI 1015 were realized at different temperatures and compared with a (Cr,AlN reference hard coating. The samples were analyzed by means of SEM (Scanning Electron Microscopy and XRD (X-Ray Diffraction measurements after Pin-on-Disk (PoD tests. Moreover TEM (Transmission Electron Microscopy analyses were carried out after 4 h annealing at 800 °C in ambient air to investigate the diffusion of vanadium to the coating surface. The tribological results at 800 °C show no improvement of the friction coefficient for the pure (Cr,AlN coating and for the layer with 5 at % V. A time-dependent decrease of the friction coefficient was achieved for the coatings with 11 at % V (µ=0.4 and 20 at % V (µ=0.4 at 800 °C.

  8. In vitro removal of toxic heavy metals by poly(γ-glutamic acid-coated superparamagnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Inbaraj BS

    2012-08-01

    Full Text Available Baskaran Stephen Inbaraj,1 Bing-Huei Chen1,21Department of Food Science, 2Graduate Institute of Medicine, Fu Jen University, Taipei, TaiwanBackground: Chelation therapy involving organic chelators for treatment of heavy metal intoxication can cause cardiac arrest, kidney overload, mineral deficiency, and anemia.Methods: In this study, superparamagnetic iron oxide nanoparticles (SPIONs modified with an edible biopolymer poly(γ-glutamic acid (PGA were synthesized by coprecipitation method, characterized and evaluated for their removal efficiency of heavy metals from a metal solution, and simulated gastrointestinal fluid (SGIF.Results: Instrumental characterization of bare- and PGA-SPIONs revealed 7% coating of PGA on SPIONs with a spherical shape and an iron oxide spinel structure belonging to magnetite. The particle sizes as determined from transmission electron microscopy images were 8.5 and 11.7 nm for bare- and PGA-SPIONs, respectively, while the magnetization values were 70.3 and 61.5 emu/g. Upon coating with PGA, the zeta potentials were shifted from positive to negative at most of the environmental pH (3–8 and biological pH (1–8, implying good dispersion in aqueous suspension and favorable conditions for heavy metal removal. Batch studies showed rapid removal of lead and cadmium with the kinetic rates estimated by pseudo-second-order model being 0.212 and 0.424 g/mg•min, respectively. A maximum removal occurred in the pH range 4–8 in deionized water and 5–8 in SGIF corresponding to most gastrointestinal pH except for the stomach. Addition of different ionic strengths (0.001–1 M sodium acetate and essential metals (Cu, Fe, Zn, Mg, Ca, and K did not show any marked influence on lead removal by PGA-SPIONs, but significantly reduced the binding of cadmium. Compared to deionized water, the lead removal from SGIF was high at all pH with the Langmuir monolayer removal capacity being 98.70 mg/g for the former and 147.71 mg/g for the

  9. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces

    International Nuclear Information System (INIS)

    Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G.; Chathuranga Senarathna, K.G.; Herath, H.M.T.U.; Premachandra, T.N.; Ranasinghe, C.S.K.; Rajapakse, R.P.V.J.; Rajapakse, R.M.G.; Edirisinghe, Mohan; Mahalingam, S.; Bandara, I.M.C.C.D.; Singh, Sanjleena

    2016-01-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO 2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. - Highlights: • Colloidal hydroxyapatite nanorods are prepared by a novel method. • Surfaces of titanium metal plates are modified by self-forming TiO 2 thin-films. • Prostheses are prepared by coating hydroxyapatite on surface modified Ti metal. • Bioactivity and noncytotoxicity are increased with surface modifications.

  10. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G.; Chathuranga Senarathna, K.G. [Department of Chemistry, Faculty of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Herath, H.M.T.U. [Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Premachandra, T.N. [Department of Veterinary Pathobiology, Faculty of Veterinary Medicine, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Ranasinghe, C.S.K. [Department of Chemistry, Faculty of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Rajapakse, R.P.V.J. [Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Department of Veterinary Pathobiology, Faculty of Veterinary Medicine, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Rajapakse, R.M.G., E-mail: rmgr@pdn.ac.lk [Department of Chemistry, Faculty of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Postgraduate Institute of Science, University of Peradeniya, 20400 Peradeniya (Sri Lanka); Edirisinghe, Mohan; Mahalingam, S. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Bandara, I.M.C.C.D. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, 2 George Street, Brisbane 4001, QLD (Australia); Singh, Sanjleena [Central Analytical Research Facility, Institute of Future Environments, Queensland University of Technology, 2 George Street, Brisbane 4001, QLD (Australia)

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO{sub 2} thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. - Highlights: • Colloidal hydroxyapatite nanorods are prepared by a novel method. • Surfaces of titanium metal plates are modified by self-forming TiO{sub 2} thin-films. • Prostheses are prepared by coating hydroxyapatite on surface modified Ti metal. • Bioactivity and noncytotoxicity are increased with surface modifications.

  11. Determination of negative permeability and permittivity of metal strip coated ferrite disks using the transmission and reflection technique

    Science.gov (United States)

    Rahman, N.; Obol, M.; Sharma, A.; Afsar, M. N.

    2010-05-01

    In this paper, a full band microwave isolator constructed from an array of metal wire-coated ferrite samples is presented. Here, the magnetic permeability of the metamaterialized structure is controlled by a relatively weak external magnetic field. The tunable permeability of the ferrites in this experiment allows us to create unidirectional wave propagation through the structure over the entire X-band frequency spectrum. The analysis presented here takes into account potential surface plasmon modes generated between the gaps of metal wires when the external magnetic field is applied. Here, we present a modification of the traditional transmission-reflection measurement method by normalizing the transmission and reflection coefficients. This modification removes the occurrence of atypical phenomena for negative imaginary components of permeability and permittivity that arises in the measurement of metamaterials. Our modified method precisely determines the refractive index, impedance, permittivity, and permeability of both traditional reciprocal networks as well as nonreciprocal networks, such as the one presented here.

  12. Preparation and characterization of metal-organic framework MIL-101(Cr)-coated solid-phase microextraction fiber.

    Science.gov (United States)

    Xie, Lijun; Liu, Shuqin; Han, Zhubing; Jiang, Ruifen; Liu, Hong; Zhu, Fang; Zeng, Feng; Su, Chengyong; Ouyang, Gangfeng

    2015-01-01

    Metal-organic frameworks (MOFs) have received great attention as novel sorbents due to their fascinating structures and intriguing potential applications in various fields. In this work, a MIL-101(Cr)-coated solid-phase microextraction (SPME) fiber was fabricated by a simple direct coating method and applied to the determination of volatile compounds (BTEX, benzene, toluene, ethylbenzene, m-xylene and o-xylene) and semi-volatile compounds (PAHs, polycyclic aromatic hydrocarbons) from water samples. The extraction and desorption conditions of headspace SPME (HS-SPME) were optimized. Under the optimized conditions, the established methods exhibited excellent extraction performance. Good precision (<7.7%) and low detection limits (0.32-1.7 ng L(-1) and 0.12-2.1 ng L(-1) for BTEX and PAHs, respectively) were achieved. In addition, the MIL-101(Cr)-coated fiber possessed good thermal stability, and the fiber can be reused over 150 times. The fiber was successfully applied to the analysis of BTEX and PAHs in river water by coupling with gas chromatography-mass spectrometry (GC-MS). The analytes at low concentrations (1.7 and 10 ng L(-1)) were detected, and the recoveries obtained with the spiked river water samples were in the range of 80.0-113% and 84.8-106% for BTEX and PAHs, respectively, which demonstrated the applicability of the self-made fiber. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Statistical characterization of surface features from tungsten-coated divertor inserts in the DIII-D Metal Rings Campaign

    Science.gov (United States)

    Adams, Jacob; Unterberg, Ezekial; Chrobak, Christopher; Stahl, Brian; Abrams, Tyler

    2017-10-01

    Continuing analysis of tungsten-coated inserts from the recent DIII-D Metal Rings Campaign utilizes a statistical approach to study carbon migration and deposition on W surfaces and to characterize the pre- versus post-exposure surface morphology. A TZM base was coated with W using both CVD and PVD and allowed for comparison between the two coating methods. The W inserts were positioned in the lower DIII-D divertor in both the upper (shelf) region and lower (floor) region and subjected to multiple plasma shots, primarily in H-mode. Currently, the post-exposure W inserts are being characterized using SEM/EDX to qualify the surface morphology and to quantify the surface chemical composition. In addition, profilometry is being used to measure the surface roughness of the inserts both before and after plasma exposure. Preliminary results suggest a correlation between the pre-exposure surface roughness and the level of carbon deposited on the surface. Furthermore, ongoing in-depth analysis may reveal insights into the formation mechanism of nanoscale bumps found in the carbon-rich regions of the W surfaces that have not yet been explained. Work supported in part by US DoE under the Science Undergraduate Laboratory Internship (SULI) program and under DE-FC02-04ER54698.

  14. Estimation of metal temperature of MCrAlY coated IN738 components based on interdiffusion behaviour

    DEFF Research Database (Denmark)

    Dahl, Kristian Vinter; Hald, John

    2006-01-01

    fraction diagrams show that a precipitate free zone forms between the coating and superalloy and grows with time. The width of the growing zone was estimated on the basis of average intensity profiles obtained from experimental x-ray maps measured using energy dispersive spectroscopy in a scanning electron......Interdiffusion at the interface between a Co-36.5Ni-17.5Cr-8Al-0.5Y, MCrAlY coating and the underlying IN738 superalloy was studied in a large matrix of specimens isothermally heat treated up to 12,000 hours at temperatures 875°C, 925°C or 950°C. Microstructural investigations and calculated phase...... microscope. A simple parabolic growth model was set up for estimating the metal temperature near the coating/ substrate interface based on the growth kinetics of the precipitate free zone. Parameters for the model were extracted from measurements of the width of the growing precipitate free zone with time...

  15. METAL OXIDE DOPED ANTIBACTERIAL POLYMERIC COATED TEXTILE MATERIALS AND ASSESSEMENT OF ANTIBACTERIAL ACTIVITY WITH ELECTRON SPIN RESONANCE

    Directory of Open Access Journals (Sweden)

    GEDIK Gorkem

    2017-05-01

    Full Text Available Antibacterial activity of a food conveyor belt is an essential property in some cases. However, every antibacterial chemical is not suitable to contact with food materials. Many metal oxides are suitable option for this purpose. The aim of this study was to investigate antibacterial properties of zinc oxide doped PVC polymer coated with electron spin resonance technique. Therefore, optimum zinc oxide containing PVC paste was prepared and applied to textile surface. Coating construction was designed as double layered, first layer did not contain antibacterial agent, thin second layer contained zinc oxide at 10-35% concentration. Oxygen radicals released from zinc oxide containing polymeric coated surface were spin trapped with DMPO (dimethylpyrroline-N-oxide spin trap and measured with Electron Spin Resonance (ESR. Besides conveyor belt samples, oxygen radical release from zinc oxide surface was measured with ESR under UV light and dark conditions. Oxygen radical release was determined even at dark conditions. Antibacterial properties were tested with ISO 22196 standard using Listeria innocua species. Measured antibacterial properties were related with ESR results. Higher concentration of zinc oxide resulted in higher antibacterial efficiency. DCFH-DA flourometric assay was carried out to determine oxidative stress insidebacteria. It is tought that, this technique will lead to decrease on the labour and time needed for conventional antibacterial tests.

  16. Potential of direct metal deposition technology for manufacturing thick functionally graded coatings and parts for reactors components

    Science.gov (United States)

    Thivillon, L.; Bertrand, Ph.; Laget, B.; Smurov, I.

    2009-03-01

    Direct metal deposition (DMD) is an automated 3D deposition process arising from laser cladding technology with co-axial powder injection to refine or refurbish parts. Recently DMD has been extended to manufacture large-size near-net-shape components. When applied for manufacturing new parts (or their refinement), DMD can provide tailored thermal properties, high corrosion resistance, tailored tribology, multifunctional performance and cost savings due to smart material combinations. In repair (refurbishment) operations, DMD can be applied for parts with a wide variety of geometries and sizes. In contrast to the current tool repair techniques such as tungsten inert gas (TIG), metal inert gas (MIG) and plasma welding, laser cladding technology by DMD offers a well-controlled heat-treated zone due to the high energy density of the laser beam. In addition, this technology may be used for preventative maintenance and design changes/up-grading. One of the advantages of DMD is the possibility to build functionally graded coatings (from 1 mm thickness and higher) and 3D multi-material objects (for example, 100 mm-sized monolithic rectangular) in a single-step manufacturing cycle by using up to 4-channel powder feeder. Approved materials are: Fe (including stainless steel), Ni and Co alloys, (Cu,Ni 10%), WC compounds, TiC compounds. The developed coatings/parts are characterized by low porosity (mechanical support structures, hermetic joints, tubes with complex geometry, and tailored inside and outside surface properties, etc.

  17. Superfocussing in a metal-coated tetrahedral tip by dimensional reduction of surface-to edge-plasmon modes

    Science.gov (United States)

    Tanaka, K.; Burr, G. W.; Grosjean, T.; Maletzky, T.; Fischer, U. C.

    2008-10-01

    Metal-coated dielectric tetrahedral tips (T-tip) have long been considered to be interesting structures for the confinement of light to nanoscopic dimensions, and in particular as probes for scanning near-field optical microscopy. Numerical investigations using the Finite-Difference Time-Domain (FDTD) method are used to explore the operation of a T-tip in extraction mode. A dipole source in close proximity to the apex excites the tip, revealing the field evolution in the tip, the resulting edge and face modes on the metal-coated surfaces, and the coupling from these modes into highly directional radiation into the dielectric interior of the tip. These results are the starting point for illumination-mode numerical investigations by a Volume Integral equation method, which compute the field distribution that develops in a T-tip when a Gaussian beam is incident into the tip, and which show that a highly confined electric field is produced at the apex of the tip. The process of light confinement can be considered as a superfocussing effect, because the intensity of the tightly confined light spot is significantly higher than that of the focussed yet much wider incident beam. The mechanism of superfocussing can be considered as a dimensional reduction of surface plasmon modes, where an edge plasmon is the most important link between the waveguide-modes inside the tip and the confined near field at the apex.

  18. Wear and corrosion behaviour of tungsten carbide based coatings with different metallic binder

    Science.gov (United States)

    Kamdi, Z.; Apandi, M. N. M.; Ibrahim, M. D.

    2017-12-01

    Tungsten carbide based coating has been well known as wear and corrosion resistance materials. However, less study is done on comparing the coating with different binder. Thus, in this work the wear and corrosion behaviour of high velocity oxy-fuel (HVOF) coatings, namely (i) tungsten carbide cobalt and (ii) tungsten carbide nickel will be evaluated. Both coatings were characterised using X-ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). The wear behaviour has been examined using the modified grinder machine by weight loss measurement. Two types of abrasive have been used that include 3 g by weight alumina and silica. While for the corrosion behaviour, it is monitored by three electrodes of electrochemical test and immersion test for 30 days in an acidic environment. The electrolyte used was 0.5 M sulphuric acids (H2SO4). It was found that the cobalt binder shows higher wear resistance compares to the nickel binder for both slurry types. The harder alumina compared to silica results in higher wear rate with removal of carbide and binder is about the same rate. For silica abrasive, due to slightly lower hardness compared to the carbide, the wear is dominated by binder removal followed by carbide detachment. For corrosion, the nickel binder shows four times higher wear resistance compared to the cobalt binder as expected due to its natural behaviour. These finding demonstrate that the selection of coating to be used in different application in this case, wear and corrosion shall be chosen carefully to maximize the usage of the coating.

  19. Investigations on the corrosion resistance of metallic bipolar plates (BPP) in proton exchange membrane fuel cells (PEMFC) - understanding the effects of material, coating and manufacturing

    Science.gov (United States)

    Dur, Ender

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples

  20. A comparison of LIDT behavior of metal-dielectric mirrors in ns and ps pulse regime at 1030 nm with regard to the coating technology

    Science.gov (United States)

    Škoda, Václav; Vanda, Jan; Uxa, Štěpán

    2017-11-01

    Several sets of mirror samples with multilayer system Ta2O5/SiO2 on silver metal layer were manufactured using either PVD or IAD coating technology. Both BK7 and fused silica substrates were used for preparation of samples. Laserinduced- damage-threshold (LIDT) of metal-dielectric mirrors was tested using a laser apparatus working at 1030 nm wavelength, in ns and ps pulse length domains in S-on-1 test mode. The measured damage threshold values at 45 deg angle of incidence and P-polarization were compared for different pulse length, substrate materials and coating technology.

  1. Pre-coating of LSCM perovskite with metal catalyst for scalable high performance anodes

    KAUST Repository

    Boulfrad, Samir

    2013-07-01

    In this work, a highly scalable technique is proposed as an alternative to the lab-scale impregnation method. LSCM-CGO powders were pre-coated with 5 wt% of Ni from nitrates. After appropriate mixing and adequate heat treatment, coated powders were then dispersed into organic based vehicles to form a screen-printable ink which was deposited and fired to form SOFC anode layers. Electrochemical tests show a considerable enhancement of the pre-coated anode performances under 50 ml/min wet H2 flow with polarization resistance decreased from about 0.60cm2 to 0.38 cm2 at 900 C and from 6.70 cm2 to 1.37 cm2 at 700 C. This is most likely due to the pre-coating process resulting in nano-scaled Ni particles with two typical sizes; from 50 to 200 nm and from 10 to 40 nm. Converging indications suggest that the latter type of particle comes from solid state solution of Ni in LSCM phase under oxidizing conditions and exsolution as nanoparticles under reducing atmospheres. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  2. Pulsed laser synthesis of ceramic-metal composite coating on steel

    International Nuclear Information System (INIS)

    Du Baoshuai; Samant, Anoop N.; Paital, Sameer R.; Dahotre, Narendra B.

    2008-01-01

    A pulsed Nd:YAG laser was employed to modify the surface properties of AISI 1010 steel with precursor of TiB 2 + Al. A set of samples were prepared with different laser processing parameters and compositions of the precursor in order to study the effect of Al on the coating. Thermal modeling was performed to quantitatively evaluate the maximum temperature and the range of cooling rate for the melting pool. Phase constituents and microstructure were characterized using X-ray diffractometer, optical microscopy, and scanning electron microscopy. Results show that TiB 2 dissociated when the Al content reached 30 wt.% or more. The composite coating with the presence of TiB 2 shows acicular TiB 2 particles embedded in the α-Fe matrix. Coatings produced using precursor of high-Al content reveals a refined cellular structure due to the high-cooling rate induced by short pulse duration. Compared with the steel substrate, microhardness and wear resistance of the coating are improved significantly.

  3. Pulsed laser synthesis of ceramic-metal composite coating on steel

    Science.gov (United States)

    Du, Baoshuai; Samant, Anoop N.; Paital, Sameer R.; Dahotre, Narendra B.

    2008-12-01

    A pulsed Nd:YAG laser was employed to modify the surface properties of AISI 1010 steel with precursor of TiB 2 + Al. A set of samples were prepared with different laser processing parameters and compositions of the precursor in order to study the effect of Al on the coating. Thermal modeling was performed to quantitatively evaluate the maximum temperature and the range of cooling rate for the melting pool. Phase constituents and microstructure were characterized using X-ray diffractometer, optical microscopy, and scanning electron microscopy. Results show that TiB 2 dissociated when the Al content reached 30 wt.% or more. The composite coating with the presence of TiB 2 shows acicular TiB 2 particles embedded in the α-Fe matrix. Coatings produced using precursor of high-Al content reveals a refined cellular structure due to the high-cooling rate induced by short pulse duration. Compared with the steel substrate, microhardness and wear resistance of the coating are improved significantly.

  4. Mid-infrared reflectance of silicone resin coating on metal substrates: Effect of polymeric binders' absorption

    Science.gov (United States)

    Ho, Wen-Dar; Ma, Chen-Chi M.

    1997-04-01

    This study examines the infrared reflectance of polymeric coatings of silicone resin, silicone modified alkyd resin, and alkyd resin on aluminum substrates. The Kubelka-Munk's two constants theory is applied to calculate the reflectance while considering the surface reflection. An integrating sphere, infrared spectroradiometer and blackbody source are utilized as the measurement systems. The extinction coefficients are determined and used to calculate the reflectances of coatings on aluminum. Coefficients in the mid-infrared region display the quantitative difference between the polymers' structure. Silicone content enhances the absorptance of the coating in the mid-IR region. The coefficients of miscible silicone resin/alkyd resin blends are determined as well. Comparing the measured and calculated reflectances reveals that the discrepancies in thinner coatings or at the IR transparent wavelength are higher and around 0.1. Such a discrepancy is owing to the polymers' non-scattering with absorption properties which affect the validity of the values involving internal reflectances considered in the model. The internal reflectance can be assigned a negligible value in the high absorption region and is also a variable depending on thickness and transparency.

  5. Spray coating of self-aligning passivation layer for metal grid lines

    NARCIS (Netherlands)

    Vuorinen, T.; Janka, M.; Rubingh, J.E.J.M.; Tuukkanen, S.; Groen, P.; Lupo, D.

    2014-01-01

    In applications such as organic light emitting diodes (OLEDs) or photovoltaic cells a homogenous voltage distribution in the large anode layer needs to be ensured by including a metal grid with a transparent conductor layer. To ensure sufficient conductivity, relatively thick metal lines are used,

  6. Fabrication of metal organic framework materials using a layer-by-layer spin coating approach

    KAUST Repository

    Eddaoudi, Mohamed

    2016-03-17

    Embodiments describe a method of depositing an MOF, including depositing a metal solution onto a substrate, spinning the substrate sufficient to spread the metal solution, depositing an organic ligand solution onto the substrate and spinning the substrate sufficient to spread the organic ligand solution and form a MOF layer.

  7. Solar selective performance of metal nitride/oxynitride based magnetron sputtered thin film coatings: a comprehensive review

    Science.gov (United States)

    Ibrahim, Khalil; Taha, Hatem; Mahbubur Rahman, M.; Kabir, Humayun; Jiang, Zhong-Tao

    2018-03-01

    Since solar-thermal collectors are considered to be the most direct way of converting solar energy into usable forms, in the last few years growing attention has been paid to the development of transition metal nitride and metal oxynitride based thin film selective surfaces for solar-thermal collectors, in order to harvest more solar energy. A solar-thermal energy system, generally, shows very high solar absorption of incident solar radiation from the solar-thermal collectors in the visible range (0.3 to 2.5 μm) and extremely low thermal losses through emission (or high reflection) in the infrared region (≥2.5 μm). The efficiency of a solar-thermal energy conversion system can be improved by the use of solar selective surfaces consisting of novel metallic nanoparticles embedded in metal nitride/oxynitride systems. In order to enhance the effectiveness of solar-thermal devices, solar selective surfaces with high thermal stability are a prerequisite. Over the years, substantial efforts have been made in the field of solar selective surfaces to attain higher solar absorptance and lower thermal emittance in high temperature (above 400 °C) applications. In this article, we review the present state-of-the-art transition metal nitride and/or oxynitride based vacuum sputtered nanostructured thin film coatings, with respect to their optical and solar selective surface applications. We have also summarized the solar selectivity data from recently published investigations, including discussion on some potential applications for these materials.

  8. TEMPERATURE DISTRIBUTION IN MULTILAYER METAL-CERAMIC COATINGS UNDER NONSTATIONARY THERMAL EFFECTS

    Directory of Open Access Journals (Sweden)

    Vasiliy M. Samoilenko

    2017-01-01

    Full Text Available Progress in the aircraft engine construction is determined by the increase of operation parameters of gas turbine engines, which is inevitably accompanied by an increase of operating temperatures and load for the vital elements of the turbine hot ducts. Furthermore, the requirements for reliability of the engine in general are also increasing. Achievement of these requirements is determined by the performance of the materials turbine blades are made of and is made possible by the application of high-heat Nickel alloys in combination with combined heat-shielding coatings.This article dwells on the problem of assessing the impact of non-stationary thermal effects on the temperature distribution in a multilayer heatproof coating. With the aim of assessing the working capacity of heatproof coatings we propose a method of calculating the temperature field for the blade profile and the coatingdepth, based on the solution of the basic one-dimensional differential equation of heat conduction.This method allows us to assess the performance of heatproof coating and also gives us an opportunity to choose a combination of heatproof coating layers for the specific operating conditions of a gas turbine engine’s blades.In addition, using the proposed method it is possible to evaluate the effect of non-stationary heat flux on the structure of high-temperature alloy of the engine’s turbine blades and, therefore, to evaluate the capacity with the given coating. At temperatures of 1150–1200 °C and higher in heat-resistant Nickel alloys there starts a coagulation process of the main reinforcing coherent particle phase on the basis of the intermetallic compound, long plates with wavy shapes are formed instead of the cuboids, a formation of topologically close-packed phases which are needle-like compositions happens. These processes lead to a significant deterioration of the strength characteristics of heat-resistant alloys. Making calculations according to

  9. CuMn1.8O4 protective coatings on metallic interconnects for prevention of Cr-poisoning in solid oxide fuel cells

    Science.gov (United States)

    Sun, Zhihao; Wang, Ruofan; Nikiforov, Alexey Y.; Gopalan, Srikanth; Pal, Uday B.; Basu, Soumendra N.

    2018-02-01

    Cr-poisoning of the cathodes due to the presence of metallic interconnects is detrimental to the performance of intermediate temperature solid oxide fuel cell stacks. Applying a protective coating on the interconnect is an effective solution to preventing Cr-poisoning. In this study, the application of a protective CuMn1.8O4 spinel coating is explored. Dense coatings are deposited on both metallic flat plates and meshes by electrophoretic deposition followed by thermal densification steps. The coating is found to be a mixture of Mn3O4 and cubic spinel phases at room temperature but is a pure cubic spinel phase between 750 °C and 850 °C. A reaction layer between the Cr2O3 scale at the coating/interconnect interface and CuMn1.8O4 coating is found to be a mixture of (Cu,Mn,Cr)3-xO4 cubic spinel phases with Cr-rich precipitates believed to be Cr2O3, indicating that the coating layer acts as a Cr getter. Solubility experiments show that 1 mol of the CuMn1.8O4 phase can getter at least 1.83 mol of Cr2O3 at 800 °C. Electrochemical testing of cells in the presence of coated interconnects show that the CuMn1.8O4 coating getters Cr effectively for 12 days at 800 °C, leading to no performance loss of the cell due to Cr-poisoning.

  10. Evaluation of thermal sprayed metallic coatings for use on the structures at Launch Complex 39

    Science.gov (United States)

    Welch, Peter J.

    1990-01-01

    The current status of the evaluation program is presented. The objective was to evaluate the applicability of Thermal Sprayed Coatings (TSC) to protect the structures in the high temperature acid environment produced by exhaust of the Solid Rocket Boosters during the launches of the Shuttle Transportation System. Only the relatively low cost aluminum TSC which provides some cathodic protection for steel appears to be a practical candidate for further investigation.

  11. An Electrochemical Investigation into the Corrosion Protection Properties of Coatings for the Active Metal Copper

    OpenAIRE

    Carragher, Ursula

    2013-01-01

    In the research presented in this thesis, corrosion protection films were synthesised and characterised. The films were based on polypyrrole (PPy) coatings doped with combinations of tartrate, oxalate and dodecylbenzene sulfonate (DBS) along with the incorporation of multiwalled carbon nanotubes (MWCNT), and viologen films adsorbed at copper. The corrosion protective properties of these films were studied and compared to the uncoated copper substrate. They were assessed and stu...

  12. Corrosion resistance of different metallic coatings on press-hardened steels for automotive

    Energy Technology Data Exchange (ETDEWEB)

    Dosdat, L.; Petitjean, J.; Vietoris, T. (ArcelorMittal Maizieres Automotive Products Research Centre, F-57283 Maizieres-les-Metz); Clauzeau, O. [Bohr Technologies (France)

    2011-06-15

    The corrosion resistance of laboratory press-hardened components in aluminized, galvanized or galvannealed boron steels was evaluated through VDA 621-415 cyclic test for the automotive industry. 22MnB5 uncoated steel for hot stamping and standard galvanized steel for cold forming were also included as references. Corrosion resistance after painting (cosmetic corrosion) was quantified by measuring the delamination of electro-deposited paint from scribed panels. The rusting on their edges was used for determining the cut-edge corrosion resistance. The corrosion resistance on unpainted deformed panels (perforating corrosion) was quantified by mass losses and pit depth measurements. Zinc-coated boron steels were found to be more resistant to cosmetic corrosion than the other materials, and slightly more resistant to cut-edge corrosion than the aluminized one. Red rust apparition could not be avoided due to the high iron content in all these hot-stamped coatings. The three coated boron steels showed similar performances in terms of resistance to perforation. Aluminized boron steel presents the advantage of being less sensitive to hot-stamping process deviation. Its robustness has been proved for many years on cars. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. METAL-MATRIX COMPOSITES AND THERMAL SPRAY COATINGS FOR EARTH MOVING MACHINES

    Energy Technology Data Exchange (ETDEWEB)

    D. Trent Weaver; Matthew T. Kiser; Frank W. Zok; Carlos G. Levi; Jeffrey Hawk

    2004-02-01

    In an effort to realize minimum of a 2x increase in wear life of ground engaging components used on mining machines, two potentially cost effective processes were explored for the production of tailored, highly abrasion resistant materials: (1) hybrid pressure casting of steel composites, and (2) arc lamp fusing of thermal spray coatings. Steel composites comprised of cermet or oxide hard particles were successfully produced using pressure casting processes, although a cost effective process has not yet been identified for oxide particles. Both composites achieved project wear targets in high stress gouging wear, but the cermet composites did not meet the targets in impact wear, due to poor matrix toughness resulting from particle dissolution. Oxide composites had superior toughness and are expected to meet impact wear goals. Arc lamp processing of thermal spray coatings was successfully demonstrated to produce a metallurgical bond at the coating interface. Functionally graded materials were developed and successfully fused to allow for the accommodation of thermal process stresses in an intermediate layer. Ultimately, three functionally graded materials were identified as having high stress, three-body abrasion resistance sufficient to exceed project goals.

  14. Corrosion resistance of BIS 2062-grade steel coated with nano-metal-oxide mixtures of iron, cerium, and titanium in the marine environment

    Science.gov (United States)

    Ashraf, P. Muhamed; Anuradha, R.

    2018-02-01

    BIS 2062-grade carbon steel is extensively used for fishing boat construction. The steel is highly susceptible to corrosion on the hull and welding joints under marine environment. Here, we demonstrate the application of a novel multifunctional nano-metal-oxide mixture comprised of iron, titanium, and cerium as a marine coating to prevent corrosion. The electrochemical performance of nano-metal-oxide mixture coatings, applied over boat-building steel, was evaluated at 3.5% NaCl medium. The nano-mixture surface coatings showed an efficient corrosion resistance with increased polarization resistance of 6043 Ω cm2 and low corrosion current density of 3.53 × 10-6 A cm-2. The electrochemical impedance spectral data exhibited improvement in the polarization resistance of outermost surface and internal layers. The coating responded faster recovery to normal state when subjected to an induced stress over the coating. The nano-material in the coating behaves as a semiconductor; this enhanced electronic activity over the surface of the steel.

  15. Shock Hazard Prevention through Self-Healing Insulative Coating on SSA Metallic Bearings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The space suit contains metallic bearings at the wrist, neck, and waist, which are exposed to the space environment. There is a need to maintain a high degree of...

  16. Shock Hazard Prevention through Self-Healing Insulative Coating on SSA Metallic Bearings, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The space suit assembly (SSA) contains metallic bearings at the wrist, neck, and waist, which are exposed to space environment, and pose a potential shock hazard....

  17. Study of Coating Geometries and Photoluminescence Properties of Metal Nanoparticles/Graphite Composites

    Directory of Open Access Journals (Sweden)

    Pasquale Barone

    2014-01-01

    Full Text Available In this work we present the results of a study of growth and characterization of metal nanoparticles (Ag, Au, and Co/carbon surfaces. The nanoparticles grew by laser ablation technique and their dimensions were controlled by light scattering study and AFM microscopy before their insertion on graphite surface. Nanoparticles appear randomly disposed on carbon surfaces aggregating to form big particles only in the case of silver. The different behavior of metal nanoparticles on carbon surface was explained in terms of different metal wetting of surface, in agreement with previous theoretical results of He et al. Chemical information, obtained by X-ray photoelectron spectroscopy, indicated that the doping process is a simple physisorption while the interfacial interaction between particles and carbon layers causes local defects in graphite structure and the appearance of a strong photoluminescence signal for all composites. Moreover, the visible optical absorption decreases about 10% indicating the progressive metallization of carbon surface.

  18. Studies on the surface modification of TiN coatings using MEVVA ion implantation with selected metallic species

    International Nuclear Information System (INIS)

    Ward, L.P.; Purushotham, K.P.; Manory, R.R.

    2016-01-01

    Highlights: • Reduced surface roughness was observed after ion implantation. • W implantation increased residual stress. • Reduced friction and wear accompanied Mo implantation. • Mo implanted layer was more resistant to breakdown during wear testing. • Ion implantation effects can be complex on various implanting species properties. - Abstract: Improvement in the performance of TiN coatings can be achieved using surface modification techniques such as ion implantation. In the present study, physical vapor deposited (PVD) TiN coatings were implanted with Cr, Zr, Nb, Mo and W using the metal evaporation vacuum arc (MEVVA) technique at a constant nominal dose of 4 × 10 16 ions cm −2 for all species. The samples were characterized before and after implantation, using Rutherford backscattering (RBS), glancing incident angle X-ray diffraction (GIXRD), atomic force microscopy (AFM) and optical microscopy. Friction and wear studies were performed under dry sliding conditions using a pin-on-disc CSEM Tribometer at 1 N load and 450 m sliding distance. A reduction in the grain size and surface roughness was observed after implantation with all five species. Little variation was observed in the residual stress values for all implanted TiN coatings, except for W implanted TiN which showed a pronounced increase in compressive residual stress. Mo-implanted samples showed a lower coefficient of friction and higher resistance to breakdown during the initial stages of testing than as-received samples. Significant reduction in wear rate was observed after implanting with Zr and Mo ions compared with unimplanted TiN. The presence of the Ti 2 N phase was observed with Cr implantation.

  19. Synthesis of Nanostructured/Macroscopic Low-Density Copper Foams Based on Metal-Coated Polymer Core-Shell Particles.

    Science.gov (United States)

    Kim, Sung Ho; Bazin, Nick; Shaw, Jessica I; Yoo, Jae-Hyuck; Worsley, Marcus A; Satcher, Joe H; Sain, John D; Kuntz, Joshua D; Kucheyev, Sergei O; Baumann, Theodore F; Hamza, Alex V

    2016-12-21

    A robust, millimeter-sized low-density Cu foam with ∼90% (v/v) porosity, ∼30 nm thick walls, and ∼1 μm diameter spherical pores is prepared by the slip-casting of metal-coated polymer core-shell particles followed by a thermal removal of the polymer. In this paper, we report our key findings that enable the development of the low-density Cu foams. First, we need to synthesize polystyrene (PS) particles coated with a very thin Cu layer (in the range of tens of nanometers). A simple reduction in the amount of Cu deposited onto the PS was not sufficient to form such a low-density Cu foams due to issues related to foam collapse and densification upon the subsequent polymer removal step. Precise control over the morphology of the Cu coating on the particles is essential for the synthesis of a lower density of foams. Second, improving the dispersion of PS-Cu particles in a suspension used for the casting as well as careful optimization of a baking condition minimize the formation of irregular large voids, leading to Cu foams with a more uniform packing and a better connectivity of neighboring Cu hollow shells. Finally, we analyzed mechanical properties of the Cu foams with a depth-sensing indentation test. The uniform Cu foams show a significant improvement in mechanical properties (∼1.5× modulus and ∼3× hardness) compared to those of uncontrolled foam samples with a similar foam density but irregular large voids. Higher surface areas and a good electric conductivity of the Cu foams present a great potential to future applications.

  20. Determination of the electrical characteristics of protective coatings and deposits on metals in media with low electrical conductivity

    International Nuclear Information System (INIS)

    Ovcharenko, V.I.; Koroleva, E.V.; Fedorova, A.N.; Sereda, G.A.

    1987-01-01

    This paper presents the results of a theoretical analysis and experimental determination of the electrical and associated protective characteristics of poorly conducting layers on metals, modeling both oxide and hydroxide deposits on the inner surfaces of the equipment as well as films of protective coatings. The analysis is performed using the linear low-frequency ac current (10 -3 -10 -6 Hz) method, which is based on the determination of the impedance Z, the admittance Y = 1/Z, the complex capacitance C = Y/j omega, where omega is the circular frequency of the alternating current, the complex dielectric constant epsilon, the tangent of the dielectric-loss angle tan δ and other quantities associated with them

  1. Characterization of carbon thin films prepared by the thermal decomposition of spin coated polyacrylonitrile layers containing metal acetates

    International Nuclear Information System (INIS)

    Daranyi, Maria; Sarusi, Istvan; Sapi, Andras; Kukovecz, Akos; Konya, Zoltan; Erdohelyi, Andras

    2011-01-01

    Polyacrylonitrile (PAN) layers were cast from dimethyl-formamide solutions onto quartz substrates by spin coating and subsequently annealed at up to 1000 o C in N 2 atmosphere. Carbonization was catalyzed by nickel or cobalt added to the solution as acetate salts. The synthesized films were approx. 970 nm thick and were characterized by Raman and infrared spectroscopy as well as thermogravimetric and electrical conductance measurements. We discuss the effects of carbonization temperature and metal concentration on the morphology, composition and electrical properties of the formed carbon layer. Increasing the amount of catalyst and the pyrolysis temperature was beneficial for the process and resulted in carbonaceous films with a higher degree of structural order as evidenced by the decreasing Raman I D /I G ratio and the increasing electrical conductivity of the films. Cobalt is a better catalyst for PAN carbonization than nickel as far as the structure of the product film is concerned.

  2. 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.

  3. Influence of surface coating on structure and properties of metallic lithium anode for rechargeable Li-O2 battery

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Q.; Wang, Q.; Ma, Q.; Song, Q.; Chen, Q.

    2017-07-01

    Amorphous lithium phosphorous oxynitride film was coated directly on pre-treated lithium metal as anode of lithium air battery by radio-frequency sputtering technique from a Li3PO4 target. The structure and composition of modified anode was analyzed before and after charge/discharge test in a lithium-air battery, which comprises 0.5M LiNO3/TEGDME as the electrolyte and super P carbon as cathode. Batteries were galvanostatically discharged by an Arbin BT-2000 battery tester between open current voltage and 2.15V vs. Li+/Li at various current regimes ranging from 0.1–0.4mA/cm2. Compared with fresh lithium, LIPON-coated anode exhibited better electrochemical performance. Good charging efficiency of 90% at a narrower voltage gap with high ionic conductivity of 9.4×10−5S/cm was achieved through optimizing lithium pre-treated conditions, sputtering N2 flows and suitable solute for electrolyte. (Author)

  4. Removal of dissolved heavy metals from pre-settled stormwater runoff by iron-oxide coated sand (IOCS)

    DEFF Research Database (Denmark)

    Møller, J.; Ledin, Anna; Mikkelsen, Peter Steen

    2002-01-01

    by IOCS after 480 pore volumes. Control columns with uncoated filter sand show that lead, copper and zinc were removed with >95%, 35% and 5%, respectively. The removal of the negative metaloxy-ion, CrO4-3 was insignificant in both IOCS and sand columns at pH=7.7. Destruction of the columns after......Sorption to iron-oxide coated sand (IOCS) is a promosing technology for removal of the dissolved heavy metal fraction in stormwater runoff. The development of a new technology is necessary since studies of stormwater runoff from traffic areas indicate that an oil separator and detention pond may...... (Pb=20, Cu=40, Zn=110, and Cr=15 ppb). Column experiments were conducted to test the influence of the infiltration rate (1 or 3 m/h) and the type of iron(hydr)oxide mineral (amorphous ferrihydrite and goethite coated sand). The results show that at least 90% of lead, copper and zinc can be removed...

  5. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-09-20

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  6. Influence of surface coating on structure and properties of metallic lithium anode for rechargeable Li-O2 battery

    Directory of Open Access Journals (Sweden)

    Qiuling Chen

    2017-03-01

    Full Text Available Amorphous lithium phosphorous oxynitride film was coated directly on pre-treated lithium metal as anode of lithium air battery by radio-frequency sputtering technique from a Li3PO4 target. The structure and composition of modified anode was analyzed before and after charge/discharge test in a lithium-air battery, which comprises 0.5 M LiNO3/TEGDME as the electrolyte and super P carbon as cathode. Batteries were galvanostatically discharged by an Arbin BT-2000 battery tester between open current voltage and 2.15 V vs. Li+/Li at various current regimes ranging from 0.1–0.4 mA/cm2. Compared with fresh lithium, LIPON-coated anode exhibited better electrochemical performance. Good charging efficiency of 90% at a narrower voltage gap with high ionic conductivity of 9.4 × 10−5 S/cm was achieved through optimizing lithium pre-treated conditions, sputtering N2 flows and suitable solute for electrolyte.

  7. Comparison of biolimus eluted from an erodible stent coating with bare metal stents in acute ST-elevation myocardial infarction (COMFORTABLE AMI trial): rationale and design

    NARCIS (Netherlands)

    Räber, L.; von Birgelen, Clemens

    2012-01-01

    Aims: Compared with bare metal stents (BMS), early generation drug-eluting stents (DES) reduce the risk of revascularisation in patients with ST-elevation myocardial infarction (STEMI) at the expense of an increased risk of very late stent thrombosis (ST). Durable polymer coatings for controlled

  8. The effect of polyaniline phosphate on mechanical and corrosive properties of protective organic coatings containing high amounts of zinc metal particles

    Czech Academy of Sciences Publication Activity Database

    Kohl, M.; Kalendová, A.; Stejskal, Jaroslav

    2014-01-01

    Roč. 77, č. 2 (2014), s. 512-517 ISSN 0300-9440 R&D Projects: GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : conductive polymers * zinc metal * organic coating Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.358, year: 2014

  9. Investigation of the microstructure of Ni and B4C ceramic-metal mixtures obtained by cold spray coating and followed by laser cladding

    Science.gov (United States)

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

    2017-10-01

    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. Main focus of this work aimed to microstructure of coatings, element content and morphology of laser tracks. At this stage, the authors focused on the interaction of the laser unit with the substance without affecting the layer-growing technology products. It is shown that coating has deformed particles of nickel and the significantly decreased content of ceramic particles B4C after cold spray. After laser cladding there are no boundaries between nickel and dramatically changes in ceramic particles.

  10. METHOD FOR TESTING COATINGS

    Science.gov (United States)

    Johns, I.B.; Newton, A.S.

    1958-09-01

    A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.

  11. Plasma coatings of nitrogen polymers on metal prostheses of the circulatory system; Recubrimientos por plasma de polimeros nitrogenados sobre protesis metalicas del sistema circulatorio

    Energy Technology Data Exchange (ETDEWEB)

    Gomez J, L. M.

    2016-07-01

    This work has a study about the synthesis of poly aniline, poly allylamine and poly pyrrole doped with iodine onto metallic surfaces similar to stents for the circulatory system. Ar, water and hydrogen peroxide plasmas were used for eroding, conditioning and synthesizing polymers that potentially reduce some rejection reactions when stents are implanted in the human body. Stents are small metallic meshes that applied inside collapsed arteries or veins enlarge the diameter and restore the blood flow, however the metallic surfaces usually cause rejection reactions that obstruct the veins again. To give solutions to this problem, in this work is studied the synthesis of biocompatible polymer coatings on the stents that resist the blood flow forming a biocompatible interface between metal and blood. The metallic substrates were eroded and chemically prepared with Ar, H{sub 2}O and/or H{sub 2}O{sub 2} glow discharges on which the polymers were synthesized by plasma. The coatings were morphologically characterized by optical, scanning electron and atomic force microscopy, the chemical structure was studied by infrared and photoelectron X-ray spectroscopy. The hydrophilicity was studied measuring the advance static contact angle and the adhesion was evaluated indirectly with scanning electron microscopy after two months submerged in buffered phosphate solutions. The results indicate that the polymers grew following the superficial morphology; that the conditioning with Ar ions erode the substrates and that the conditioning with H{sub 2}O or H{sub 2}O{sub 2} erodes and activates the surface generating oxygen bridges which help in the polymer-metal adhesion. The chemical structure of the polymeric coatings contain crosslinked structures that correspond to links between monomers with the participation of all atoms, states that suggest monomer fragmentation and oxidation and states that indicate oxygen bridges in the polymers. The coatings had contact angles close to 90

  12. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces.

    Science.gov (United States)

    Wijesinghe, W P S L; Mantilaka, M M M G P G; Chathuranga Senarathna, K G; Herath, H M T U; Premachandra, T N; Ranasinghe, C S K; Rajapakse, R P V J; Rajapakse, R M G; Edirisinghe, Mohan; Mahalingam, S; Bandara, I M C C D; Singh, Sanjleena

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Air- and Water-Resistant Noble Metal Coated Ferromagnetic Cobalt Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Lentijo-Mozo, Sergio; Tan, Reasmey P.; Garcia-Marcelot, Cécile; Altantzis, Thomas; Fazzini, Pier-Francesco; Hungria, Teresa; Cormary, Benoit; Gallagher, James R.; Miller, Jeffrey T.; Martinez, Herve; Schrittwieser, Stefan; Schotter, Joerg; Respaud, Marc; Bals, Sara; Tendeloo, Gustaaf Van; Gatel, Christophe; Soulantica, Katerina

    2015-03-24

    Cobalt nanorods possess ideal magnetic properties for applications requiring magnetically hard nanoparticles. However, their exploitation is undermined by their sensitivity toward oxygen and water, which deteriorates their magnetic properties. The development of a continuous metal shell inert to oxidation could render them stable, opening perspectives not only for already identified applications but also for uses in which contact with air and/or aqueous media is inevitable. However, the direct growth of a conformal noble metal shell on magnetic metals is a challenge. Here, we show that prior treatment of Co nanorods with a tin coordination compound is the crucial step that enables the subsequent growth of a continuous noble metal shell on their surface, rendering,them air- and water-resistant, while conserving the monocrystallity, metallicity and the Magnetic properties of the Co core. Thus, the as-synthesized tore shell ferromagnetic nanorods combine high;Magnetization and strong uniaxial Magnetic anisotropy, even after exposure to air and water, and hold promise for successful implementation in in vitro biodiagnostics requiring probes Of high magnetization and anisotropic shape.

  14. Air- and Water-Resistant Noble Metal Coated Ferromagnetic Cobalt Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Lentijo-Mozo, Sergio [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Tan, Reasmey P. [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Garcia-Marcelot, Cécile [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Centre d’Elaboration de Matériaux et d’Etudes Structurales (CEMES-CNRS), 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse, France; Altantzis, Thomas [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; Fazzini, Pier-Francesco [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Hungria, Teresa [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Cormary, Benoit [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Gallagher, James R. [Chemical Science and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Argonne, Illinois 60439, United States; Miller, Jeffrey T. [Chemical Science and Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Argonne, Illinois 60439, United States; Martinez, Herve [IPREM-ECP CNRS UMR 5254, Université de Pau, Hélioparc Pau Pyrénées, 2 av. Pierre Angot, 64053 Pau Cedex 9, France; Schrittwieser, Stefan [Molecular Diagnostics, AIT Austrian Institute of Technology, Vienna, Donau City Strasse 1, 1220 Vienna, Austria; Schotter, Joerg [Molecular Diagnostics, AIT Austrian Institute of Technology, Vienna, Donau City Strasse 1, 1220 Vienna, Austria; Respaud, Marc [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France; Bals, Sara [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; Tendeloo, Gustaaf Van [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; Gatel, Christophe [Centre d’Elaboration de Matériaux et d’Etudes Structurales (CEMES-CNRS), 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse, France; Soulantica, Katerina [Laboratoire de Physique et Chimie des Nano-objets (LPCNO), Université de Toulouse, INSA, UPS, CNRS, 135 avenue de Rangueil, 31077 Toulouse, France

    2015-02-25

    Cobalt nanorods possess ideal magnetic properties for applications requiring magnetically hard nanoparticles. However, their exploitation is undermined by their sensitivity toward oxygen and water, which deteriorates their magnetic properties. The development of a continuous metal shell inert to oxidation could render them stable, opening perspectives not only for already identified applications but also for uses in which contact with air and/or aqueous media is inevitable. However, the direct growth of a conformal noble metal shell on magnetic metals is a challenge. Here, we show that prior treatment of Co nanorods with a tin coordination compound is the crucial step that enables the subsequent growth of a continuous noble metal shell on their surface, rendering them air- and water-resistant, while conserving the monocrystallity, metallicity and the magnetic properties of the Co core. Thus, the as-synthesized core–shell ferromagnetic nanorods combine high magnetization and strong uniaxial magnetic anisotropy, even after exposure to air and water, and hold promise for successful implementation in in vitro biodiagnostics requiring probes of high magnetization and anisotropic shape.

  15. Sulfonated Polyaniline Coated Mercury Film Electrodes for Voltammetric Analysis of Metals in Water

    Directory of Open Access Journals (Sweden)

    Denise Alves Fungaro

    2001-11-01

    Full Text Available The electrochemical polymerization of 2-aminobenzenesulfonic acid with and without aniline has been carried by cyclic potencial sweep in sulfuric acid solution at the glassy carbon electrode. The polymer and copolymer formed have been characterized voltammetrically. The sulfonated polyaniline coated mercury thin-film electrodes have been evaluated for use with anodic stripping voltammetry. The electrodes were tested and compared with a conventional thin-film mercury electrode. Calibration plots showed linearity up to 10-7 mol L-1. Detection limits for zinc, lead and cadmium test species are very similar at around 12 nmol L-1. Applications to analysis of waters samples are demonstrated.

  16. Surface modification, organometallic and polyaryl polymer coatings, and flame spray technologies for preventing corrosion of metals. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T.

    1995-07-01

    To improve adherent properties of electrogalvanized steel (EGS) to polymeric topcoats, the surfaces of EGS were modified by polyelectrolyte-modified zinc phosphating solution. The electrochemical reaction between phosphating solution and EGS led to the complete coverage with fully grown hopeite crystals after only 5 sec treatment, thereby improving adhesion to topcoating and providing protection of EGS against corrosion. To evaluate the ability of polyphenylene sulfide (PPS) polyaryl thermoplastic coatings to protect zinc phosphate (Zn{center_dot}Ph)treated steels from corrosion in a wet, harsh environment ( 1.0 wt % H{sub 2}SO{sub 4}, 3.0 wt % NaCl and 96.0 wt % water at temperatures from 25{degrees} to 200{degree}C), we exposed them in an autoclave to attempt heating-cooling cyclic fatigue tests (1 cycle = 12 hr at 200{degrees}C + 12 hr at 25{degrees}C) up to 90 times. The major chemical reaction at the interface between the PPS and Zn in the Zn-Ph layer during cycling led to the formation of ZnS reaction product, which enhanced the Zn-Ph-to-PPS adhesive bond; correspondingly, there were no signs of peeling and separation of the coating after 90 cycles. organometallosiloxane polymer (OMSP) was synthesized through the hydrolysis-condensation reaction of the mixed precursor solutions of the N-[3-(triethoxysily)propyl]-4,5,-dihydroimidazole and {Beta}-trimethoxysilylethyl-2-pyridine sols in liquor medium and the metal alkoxides and metallocene dichloride dissolved in water or tetrahydrofurane. The OMSP films (thickness, 0. 5 to 1. 0 {mu}m) deposited by simple dip-withdrawing coating methods to aluminum alloys displayed the impedance of > 10{sup 6} ohm-cm {sup 2} after exposure for 40 days in 0.5 N NaCl solution at 25{degrees}C and the 3000 hr-salt spray resistance. Using a flame spray coating process, the methacrylic acid-modified polyethylene copolymer was overlaid onto cold rolled steel surfaces.

  17. Metal nitride coatings by physical vapor deposition (PVD) for a wear resistant aluminum extrusion die.

    Science.gov (United States)

    Lee, Su Young; Kim, Sang Ho

    2014-12-01

    The purpose of this study is to investigate the friction and wear behaviors of CrN, TiN, CrAlN, and TiAIN coated onto SKD61 for application to Al 7000 series extrusion dies. On the wear test, the experimental parameters are the load and the counter material's temperature. The results showed that the friction coefficient increased with load but decreased with the counter material's temperature, and the friction coefficients of CrN and CrAIN were lower than the friction coefficients of TiAIN and TIN, especially at a higher temperature. The wear track with different coatings identified different wear behaviors; the wear behavior of CrAIN was found to be abrasive, but the wear behavior of TiN, CrN, and TiAIN was adhesive. Therefore, CrAIN showed the least wear loss with a lower friction coefficient and less adhesion with counter materials at the highest range of wear load and temperature. This resulted in the easy formation of aluminum oxide in the wear track and less Al adhesion; moreover during the hard second phase, AIN dispersed in the film during deposition.

  18. Grey–Taguchi method to optimize the percent zinc coating balances edge joints for galvanized steel sheets using metal inert gas pulse brazing process

    Directory of Open Access Journals (Sweden)

    Khasempong Songsorn

    2016-06-01

    Full Text Available The objective of this work was to optimize the percent zinc coating balances edge joints of galvanized steel sheets using the metal inert gas pulse brazing process. The Taguchi method and grey relational analysis were used to determine the relationship between the metal inert gas pulse brazing process parameters and percent zinc coating balances edge joints. The metal inert gas pulse brazing process parameters used in this study included wire feed speeds, arc voltages, travel speed, peak currents, and pulse frequency. The characteristics of metal inert gas pulse brazing process that were considered to find response were percent zinc coating balances edge joints on the upper edge joint (PZBEJ1, the lower edge joint (PZBEJ2, and the back sides of the edge joint (PZBEJ3. Analysis of variance was performed to determine the impact of an individual process parameter on the quality parameters. The results showed that the optimal parameters in which grey relational grade increases at the highest level were wire feed speeds at 3.25 m/min, arc voltages at 16 V, travel speeds at 0.9 m/min, peak currents at 425 A, and pulse frequency at 35 Hz. These parameters gave a 74.90% higher response value than those of the initial parameters of metal inert gas pulse brazing process.

  19. Microstructure of Ti6Al4V reinforced by coating W particles through laser metal deposition

    CSIR Research Space (South Africa)

    Ndou, N

    2016-10-01

    Full Text Available The study of laser power on the deposited of Ti64l4V/W was investigated. The laser metal deposition technique has proven to be a process that is sustainable. The microstructure and microhardness properties of a Tungsten powder strengthened composite...

  20. Study rationale and protocol: prospective randomized comparison of metal ion concentrations in the patient's plasma after implantation of coated and uncoated total knee prostheses.

    Science.gov (United States)

    Lützner, Jörg; Dinnebier, Gerd; Hartmann, Albrecht; Günther, Klaus-Peter; Kirschner, Stephan

    2009-10-14

    Any metal placed in a biological environment undergoes corrosion. Thus, with their large metallic surfaces, TKA implants are particularly prone to corrosion with subsequent release of metal ions into the human body which may cause local and systemic toxic effects and hypersensitivity reactions, and increase cancer risk. To address this problem, a new 7-layer zirconium coating developed especially for cobalt-chrome orthopaedic implants was tested biomechanically and found to lower metal ion release. The purpose of the proposed clinical trial is to compare the metal ion concentration in patients' plasma before and after implantation of a coated or uncoated TKA implant. In this randomised controlled trial, 120 patients undergoing primary TKA will be recruited at the Department of Orthopaedic Surgery of the University Hospital in Dresden, Germany, and randomised to either the coated or uncoated prosthesis. Outcome assessments will be conducted preoperatively and at 3 months, 12 months and 5 years postoperatively. The primary clinical endpoint will be the chromium ion concentration in the patient's plasma after 1 and 5 years. Secondary outcomes include cobalt, molybdenum and nickel ion concentrations after 1 and 5 years, allergy testing for hypersensitivity against one of these metals, the Knee Society Score to assess clinical and physical function of the knee joint, the self-assessment Oxford Score and the Short Form 36 quality of live questionnaire. The metal ion concentration in the patient's plasma has been shown to increase after TKA, its eventual adverse effects being widely debated. In the light of this discussion, ways to reduce metal ion release from orthopaedic implants should be studied in detail. The results of this investigation may lead to a new method to achieve this goal. TRIALS REGISTER: Clinicaltrials registry NCT00862511.

  1. Study rationale and protocol: prospective randomized comparison of metal ion concentrations in the patient's plasma after implantation of coated and uncoated total knee prostheses

    Directory of Open Access Journals (Sweden)

    Günther Klaus-Peter

    2009-10-01

    Full Text Available Abstract Background Any metal placed in a biological environment undergoes corrosion. Thus, with their large metallic surfaces, TKA implants are particularly prone to corrosion with subsequent release of metal ions into the human body which may cause local and systemic toxic effects and hypersensitivity reactions, and increase cancer risk. To address this problem, a new 7-layer zirconium coating developed especially for cobalt-chrome orthopaedic implants was tested biomechanically and found to lower metal ion release. The purpose of the proposed clinical trial is to compare the metal ion concentration in patients' plasma before and after implantation of a coated or uncoated TKA implant. Methods/Design In this randomised controlled trial, 120 patients undergoing primary TKA will be recruited at the Department of Orthopaedic Surgery of the University Hospital in Dresden, Germany, and randomised to either the coated or uncoated prosthesis. Outcome assessments will be conducted preoperatively and at 3 months, 12 months and 5 years postoperatively. The primary clinical endpoint will be the chromium ion concentration in the patient's plasma after 1 and 5 years. Secondary outcomes include cobalt, molybdenum and nickel ion concentrations after 1 and 5 years, allergy testing for hypersensitivity against one of these metals, the Knee Society Score to assess clinical and physical function of the knee joint, the self-assessment Oxford Score and the Short Form 36 quality of live questionnaire. Discussion The metal ion concentration in the patient's plasma has been shown to increase after TKA, its eventual adverse effects being widely debated. In the light of this discussion, ways to reduce metal ion release from orthopaedic implants should be studied in detail. The results of this investigation may lead to a new method to achieve this goal. Trials register Clinicaltrials registry NCT00862511

  2. Styrene N-vinylpyrrolidone metal-nanocomposites as antibacterial coatings against Sulfate Reducing Bacteria.

    Science.gov (United States)

    Fathy, M; Badawi, A; Mazrouaa, A M; Mansour, N A; Ghazy, E A; Elsabee, M Z

    2013-10-01

    Copolymer of styrene, and vinylpyrrolidone was prepared by various techniques. Different nanometals and nanometal oxides were added into the copolymer as antimicrobial agents against Sulfate Reducing Bacteria (SRB). The nanocomposite chemical structure was confirmed by using FTIR, (1)H NMR spectroscopy and thermogravimetric analysis (TGA). The biocidal action of these nanocomposites against the SRB was detected using sulfide determination method in Postgate medium B. The data indicated that the nanocomposites had an inhibitory effect on the growth of SRB and reduced the bacterial corrosion rate of mild steel coupons. The prepared nanocomposites have high inhibition efficiency when applied as coatings and show less efficiency when applied as solids or solution into SRB medium. The copolymer and its nanocomposites effectively reduced the total corrosion rate as determined by total weight loss method. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Metal-coated silicon nanopillars with large Raman enhancement for explosives detection

    Science.gov (United States)

    Schmidt, Michael Stenbæk; Boisen, Anja

    2010-04-01

    In this paper we present a quick and easy method for producing relatively large areas of nanostructured substrate that enhances the Raman effect. Standard semiconductor processing techniques are used, hence it is possible to narrowly control the parameters of the fabrication process to create free standing silicon nanopillars with controlled aspect ratios and spacing. The silicon nanopillars are coated by thin films of silver and/or gold to create Raman active surfaces. Surface enhanced Raman scattering (SERS) spectroscopy has numerous applications in chemical sensing, with high sensitivity and fast analysis speed seen as the main advantages. We show how these novel substrates can be used in an explosives sensor. Under the framework of the Xsense project at the Technical University of Denmark (DTU) which combines four independent sensing techniques, these SERS substrates coupled with commercially available microspectrometers will be included in handheld explosives detectors with applications in homeland security and landmine clearance.

  4. The influence of adsorption coating on molecular heat transfer in the system `rarefied gas — metal'

    Science.gov (United States)

    Ukhov, A. I.; Borisov, S. F.; Porodnov, B. T.

    2010-03-01

    Based on the classical concept of atomic motion and the Goodman and Wachman lattice theory, we have developed a computer program to model the equilibrium and non-equilibrium scattering of helium atoms by 3D tungsten crystal lattice with allowance for adsorption surface coating. Within the concept of energy accommodation coefficient, we have calculated the rate of molecular heat transfer of helium to clean tungsten surface or to tungsten surface partially covered with an adsorbate. The calculations were performed for various surface temperatures. The calculated dependences were compared to test data obtained in experiments with surfaces controlled in terms of their chemical composition. Within the developed approach, the simulations proved capable of providing an adequate description to experimental data obtained for the equilibrium energy accommodation coefficient on the clean surface, and also for the non-equilibrium energy accommodation coefficient for the surface partially covered with adsorbate.

  5. Roll-to-Roll Manufacturing of Robust Superhydrophobic Coating on Metallic Engineering Materials.

    Science.gov (United States)

    Dong, Shuliang; Wang, Zhenlong; Wang, Yukui; Bai, Xuelin; Fu, Yong Qing; Guo, Bin; Tan, Chaoliang; Zhang, Jia; Hu, PingAn

    2018-01-17

    Creating a robust superhydrophobic surface on the conventional engineering materials at mass production is of great importance for a self-cleaning, anti-icing, nonwetting surface and low flow resistance in industrial applications. Herein, we report a roll-to-roll strategy to create durable and robust superhydrophobic surfaces with designed micro-/nanoscale hierarchical structures on many conventional engineering materials by combining electrical discharge machining and coating of carbon nanoparticles, followed by oil penetration and drying. The treated surface shows good superhydrophobic properties with a static water contact angle of 170 ± 2° and slide angle of 3 ± 1°. The treated surface also exhibits good resilience and maintains the performance after being tested in various harsh conditions, including water flushing for several days, sand abrasion, scratching with sandpapers, and corrosive solution. Significantly, the superhydrophobic surfaces also show a high efficiency of self-cleaning properties even after oil contamination during applications.

  6. Corrosion behavior of Al-Fe-sputtering-coated steel, high chromium steels, refractory metals and ceramics in high temperature Pb-Bi

    International Nuclear Information System (INIS)

    Abu Khalid, Rivai; Minoru, Takahashi

    2007-01-01

    Corrosion tests of Al-Fe-coated steel, high chromium steels, refractory metals and ceramics were carried out in high temperature Pb-Bi at 700 C degrees. Oxygen concentrations in this experiment were 6.8*10 -7 wt.% for Al-Fe-coated steels and 5*10 -6 wt.% for high chromium steels, refractory metals and ceramics. All specimens were immersed in molten Pb-Bi in a corrosion test pot for 1.000 hours. Coating was done with using the unbalanced magnetron sputtering (UBMS) technique to protect the steel from corrosion. Sputtering targets were Al and SUS-304. Al-Fe alloy was coated on STBA26 samples. The Al-Fe alloy-coated layer could be a good protection layer on the surface of steel. The whole of the Al-Fe-coated layer still remained on the base surface of specimen. No penetration of Pb-Bi into this layer and the matrix of the specimen. For high chromium steels i.e. SUS430 and Recloy10, the oxide layer formed in the early time could not prevent the penetration of Pb-Bi into the base of the steels. Refractory metals of tungsten (W) and molybdenum (Mo) had high corrosion resistance with no penetration of Pb-Bi into their matrix. Penetration of Pb-Bi into the matrix of niobium (Nb) was observed. Ceramic materials were SiC and Ti 3 SiC 2 . The ceramic materials of SiC and Ti 3 SiC 2 had high corrosion resistance with no penetration of Pb-Bi into their matrix. (authors)

  7. Application of oxide coatings to metals in electrolyte solutions by microplasma methods

    Directory of Open Access Journals (Sweden)

    Vladimirovich Timoshenko, Aleksander

    2000-10-01

    Full Text Available Microplasma oxidation of aluminium alloys in alkaline colloidal and finely dispersed solutions is analysed. Oxidation causes both electrolyte and alloy components to be incorporated into resultant coatings, which affect the deposition parameters and coating properties. Oxidation process has been studied at spark, micro-are, and are stages under an alternating current polarisation and under purely anodic polarisation. It is shown that the cathodic component of the alternating current not only facilitates subsequent anodic process, but also contributes to the formation of an oxide layer.

    Se ha examinado la aplicación de procesos de oxidación por microplasma de las aleaciones de aluminio en electrólitos alcalinos, tanto en estado coloidal como microdisperso. Se descubrió que durante el proceso de la oxidación, en la estructura del recubrimiento óxido, van incluyéndose tanto los componentes del electrólito como los de la aleación, lo que modifica las propiedades y parámetros de deposición de las aleaciones obtenidas. El proceso de la oxidación se examinó a lo largo de las siguientes etapas: chispas, micro-arco y arco, tanto bajo la polarización de la corriente alterna como en condiciones de polarización anódica. Se ha demostrado que la componente catódica de la corriente alterna polarizante no sólo facilita los siguientes procesos anódicos, sino que además contribuye a los procesos de formación de la capa óxida.

  8. Evaluation of Various Metallic Coatings on Steel to Mitigate Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Hajime Ikigai

    2009-02-01

    Full Text Available In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  9. Evaluation of various metallic coatings on steel to mitigate biofilm formation.

    Science.gov (United States)

    Kanematsu, Hideyuki; Ikigai, Hajime; Yoshitake, Michiko

    2009-02-01

    In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  10. Performance comparison of dye-sensitized solar cells by using different metal oxide- coated TiO2 as the photoanode

    Directory of Open Access Journals (Sweden)

    Sun Xuhui

    2014-01-01

    Full Text Available In order to increase the conversion efficiency of dye-sensitized solar cells, TiO2 photoanode surface is often covered with a metal oxide layer to form a core-shell composite structure. Different metal oxide coating on TiO2 as composite photoanodes can affect the cell efficiency variously. However, there still lacks the crosswise comparison among the effects of different metal oxides on TiO2 photoanode. In this study, TiO2 was coated with Al2O3, CaO, ZnO, MgO, Fe2O3 or Bi2O3 separately by liquid phase deposition method. The results indicated that cells with TiO2/Al2O3, TiO2/ZnO, TiO2/CaO, or TiO2/MgO composite film as a photoanode had higher conversion efficiency than those with un-coated TiO2 films. TiO2/Al2O3 showed the highest efficiency and TiO2/CaO ranked second. On the contrary, cells with TiO2/Bi2O3 or TiO2/Fe2O3 composite film as a photoanode had lower conversion efficiency than those with un-coated TiO2 films. The mechanism of the cell efficiency change was also investigated. To get higher conversion efficiency, matched energy level of the metal oxide with TiO2 is the first prerequisite, and then the optimum coating thickness is also a necessary condition.

  11. In vitro metal ion release and biocompatibility of amorphous Mg67Zn28Ca5 alloy with/without gelatin coating.

    Science.gov (United States)

    Chan, W Y; Chian, K S; Tan, M J

    2013-12-01

    Amorphous zinc-rich Mg-Zn-Ca alloys have exhibited good tissue compatibility and low hydrogen evolution in vivo. However, suboptimal cell-surface interaction on magnesium alloy surface observed in vitro could lead to reduced integration with host tissue for regenerative purpose. This study aims to improve cell-surface interaction of amorphous Mg67Zn28Ca5 alloy by coating a gelatin layer by electrospinning. Coated/uncoated alloys were immersed and extracted for 3 days under different CO2. The immersion results showed that pH and metal ion release in the alloy extracts were affected by gelatin coating and CO2, suggesting their roles in alloy biocorrosion and a mechanism has been proposed for the alloy-CO2 system with/without coating. Cytotoxicity results are evident that gelatin-coated alloy with 2-day crosslinking not only exhibited no indirect cytotoxicity, but also supported attachment of L929 and MG63 cell lines around/on the alloy with high viability. Therefore, amorphous Mg67Zn28Ca5 alloy coated with gelatin by electrospinning technique provides a useful method to improve alloy biocompatibility. © 2013 Elsevier B.V. All rights reserved.

  12. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  13. Potential-modulated intercalation of alkali cations into metal hexacyanoferrate coated electrodes. 1998 annual progress report

    International Nuclear Information System (INIS)

    Schwartz, D.T.

    1998-01-01

    'This program is studying potential-driven cation intercalation and deintercalation in metal hexacyanoferrate compounds, with the eventual goal of creating materials with high selectivity for cesium separations and long cycle lifetimes. The separation of radiocesium from other benign cations has important implications for the cost of processing a variety of cesium contaminated DOE wasteforms. This report summarizes results after nine months of work. Much of the initial efforts have been directed towards quantitatively characterizing the selectivity of nickel hexacyanoferrate derivatized electrodes for intercalating cesium preferentially over other alkali metal cations. Using energy dispersive xray spectroscopy (ex-situ, but non-destructive) and ICP analysis (ex-situ and destructive), the authors have demonstrated that the nickel hexacyanoferrate lattice has a strong preference for intercalated cesium over sodium. For example, when ions are reversibly loaded into a nickel hexacyanoferrate thin film from a solution containing 0.9999 M Na + and 0.0001 M Cs + , the film intercalates 40% as much Cs + as when loaded from pure 1 M Cs + containing electrolyte (all electrolytes use nitrates as the common anion). The authors have also shown that, contrary to the common assumptions found in the literature, a significant fraction of the thin film is not active initially. A new near infrared laser has been purchased and is being added to the Raman spectroscopy facilities to allow in-situ studies of the intercalation processes.'

  14. Strategies for specifically directing metal functionalization of protein nanotubes: constructing protein coated silver nanowires.

    Science.gov (United States)

    Carreño-Fuentes, Liliana; Ascencio, Jorge A; Medina, Ariosto; Aguila, Sergio; Palomares, Laura A; Ramírez, Octavio T

    2013-06-14

    Biological molecules that self-assemble in the nanoscale range are useful multifunctional materials. Rotavirus VP6 protein self-assembles into tubular structures in the absence of other rotavirus proteins. Here, we present strategies for selectively directing metal functionalization to the lumen of VP6 nanotubes. The specific in situ metal reduction in the inner surface of nanotube walls was achieved by the simple modification of a method previously reported to functionalize the nanotube outer surface. Silver nanorods and nanowires as long as 1.5 μm were formed inside the nanotubes by coalescence of nanoparticles. Such one-dimensional structures were longer than others previously obtained using bioscaffolds. The interactions between silver ions and the nanotube were simulated to understand the conditions that allowed nanowire formation. Molecular docking showed that a naturally occurring arrangement of aspartate residues enabled the stabilization of silver ions on the internal surface of the VP6 nanotubes. This is the first time that such a spatial arrangement has been proposed for the nucleation of silver nanoparticles, opening the possibility of using such an array to direct functionalization of other biomolecules. These results demonstrate the natural capabilities of VP6 nanotubes to function as a versatile biotemplate for nanomaterials.

  15. Cotransport of microorganisms and metallic colloids in quartz sand or iron oxide-coated sand under real site hydrogeological conditions

    Science.gov (United States)

    Yu, Tong; Wen, Yujuan; Yang, Xinyao; Yang, Yuesuo

    2017-04-01

    The need for studying the fate and transport of engineered and naturally-occurring nanoparticles is of great concern in the past decade. Wudalianchi scenic spot as a famous International Geological Park has the biggest cold spring in China, which is also one of the three biggest cold spring in the world, with a history of over 200 years using in drinking and medical purpose. Thousands of tourists all over the world travelling here each year to enjoy the high quality mineral water and take a bath in the cold spring and "mud-bath" with special medication purposes. Recreation activities gave rise to the engineered nanomaterials (ENMs) releasing into the water environment and increase the risk of contamination. Therefore, it is necessary to evaluate the effect of ENMs-exposure in natural environment and how it influences the transport of microorganisms of Wudalianchi in/without the presence of natural colloids (humic acid) under a series of ion strength. A thorough critical literature review of both work in the study site and the bio/nano-particle transport in porous media was a kick-off of the study. With support of the site investigations and sampling of groundwater, surface water and surface mud/soils, further numerical modelling of the hydrogeochemical speciation of the groundwater was carried out, indicating comprehensive water-rock interactions of this particular region. Metallic nanoparticles (MNPs), including metals, metal oxides and other metal-containing nanoparticles, are produced and ubiquitously applied to medical, cosmetic, photonics and catalysis industries, etc. TiO2, a widely used raw material for cosmetic industries (e.g., sunscreens), was used in this study to represent MNPs. The microorganisms used in this study were extracted from the soil in Wudalianchi. Humic acid (HA), a key component of dissolved organic matter (DOM) chosen as the natural colloids in this study, are ubiquitous and significant constituents in soils and water environment that

  16. 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.

  17. Use of an arc plasma rotating in a magnetic field for metal coating glass substrates

    International Nuclear Information System (INIS)

    Vukanovic, V.; Butler, S.; Kapur, S.; Krakower, E.; Allston, T.; Belfield, K.; Gibson, G.

    1983-01-01

    First results are reported about deposition of metals on glass substrate using a low current arc plasma source at atmospheric pressure. The arc source consists of a graphite cathode rod placed on the axis of a graphite anode cylinder aligned in a magnetic field. The carrier gas is argon. The deposition material, zinc or gold, is evaporated from a reservoir in the cathode. Depositions on flat substrates positioned on the periphery of the rotating plasma within the anode tube and in a jet outside the anode have been investigated. The investigations are planned to lead towards laser fusion target pusher layer fabrication. This fabrication would be facilitated by a high pressure deposition process where target levitation is readily performed

  18. One-Step Carbon Coating and Polyacrylamide Functionalization of Fe₃O₄ Nanoparticles for Enhancing Magnetic Adsorptive-Remediation of Heavy Metals.

    Science.gov (United States)

    Habila, Mohamed A; ALOthman, Zeid A; El-Toni, Ahmed Mohamed; Labis, Joselito Puzon; Khan, Aslam; Al-Marghany, Adel; Elafifi, Hussein Elsayed

    2017-11-27

    Magnetic nanoparticles are used in adsorptive removal of heavy metals from polluted wastewater. However, their poor stability in an acidic medium necessitates their protection with a coating layer. Coating magnetic nanoparticles with carbon showed proper protection but the heavy metal removal efficiency was slightly weak. However, to boost the removal efficiencies of surface functionalization, polyacrylamide was applied to carbon-coated Fe₃O₄ nanoparticles. In this paper, to facilitate the synthesis process, one-step carbon coating and polyacrylamide functionalization were conducted using the hydrothermal technique with the aim of enhancing the adsorptive removal capacity of Fe₃O₄ nanoparticles towards some heavy metals such as Cu(II), Ni(II), Co(II), and Cd(II). The results showed that the one-step process succeeded in developing a carbon coating layer and polyacrylamide functionality on Fe₃O₄ nanoparticles. The stability of the magnetic Fe₃O₄ nanoparticles as an adsorbent in an acidic medium was improved due to its resistance to the dissolution that was gained during carbon coating and surface functionalization with polyacrylamide. The adsorptive removal process was investigated in relation to various parameters such as pH, time of contact, metal ion concentrations, adsorbent dose, and temperature. The polyacrylamide functionalized Fe₃O₄ showed an improvement in the adsorption capacity as compared with the unfunctionalized one. The conditions for superior adsorption were obtained at pH 6; time of contact, 90 min; metal solution concentration, 200 mg/L; adsorbent dose, 0.3 g/L. The modeling of the adsorption data was found to be consistent with the pseudo-second-order kinetic model, which suggests a fast adsorption process. However, the equilibrium data modeling was consistent with both the Langmuir and Freundlich isotherms. Furthermore, the thermodynamic parameters of the adsorptive removal process, including Δ G °, Δ H °, and Δ S

  19. One-Step Carbon Coating and Polyacrylamide Functionalization of Fe3O4 Nanoparticles for Enhancing Magnetic Adsorptive-Remediation of Heavy Metals

    Directory of Open Access Journals (Sweden)

    Mohamed A. Habila

    2017-11-01

    Full Text Available Magnetic nanoparticles are used in adsorptive removal of heavy metals from polluted wastewater. However, their poor stability in an acidic medium necessitates their protection with a coating layer. Coating magnetic nanoparticles with carbon showed proper protection but the heavy metal removal efficiency was slightly weak. However, to boost the removal efficiencies of surface functionalization, polyacrylamide was applied to carbon-coated Fe3O4 nanoparticles. In this paper, to facilitate the synthesis process, one-step carbon coating and polyacrylamide functionalization were conducted using the hydrothermal technique with the aim of enhancing the adsorptive removal capacity of Fe3O4 nanoparticles towards some heavy metals such as Cu(II, Ni(II, Co(II, and Cd(II. The results showed that the one-step process succeeded in developing a carbon coating layer and polyacrylamide functionality on Fe3O4 nanoparticles. The stability of the magnetic Fe3O4 nanoparticles as an adsorbent in an acidic medium was improved due to its resistance to the dissolution that was gained during carbon coating and surface functionalization with polyacrylamide. The adsorptive removal process was investigated in relation to various parameters such as pH, time of contact, metal ion concentrations, adsorbent dose, and temperature. The polyacrylamide functionalized Fe3O4 showed an improvement in the adsorption capacity as compared with the unfunctionalized one. The conditions for superior adsorption were obtained at pH 6; time of contact, 90 min; metal solution concentration, 200 mg/L; adsorbent dose, 0.3 g/L. The modeling of the adsorption data was found to be consistent with the pseudo-second-order kinetic model, which suggests a fast adsorption process. However, the equilibrium data modeling was consistent with both the Langmuir and Freundlich isotherms. Furthermore, the thermodynamic parameters of the adsorptive removal process, including ΔG°, ΔH°, and ΔS°, indicated a

  20. Influence of Ni-P Coated SiC and Laser Scan Speed on the Microstructure and Mechanical Properties of IN625 Metal Matrix Composites

    Science.gov (United States)

    Sateesh, N. H.; Kumar, G. C. Mohan; Krishna, Prasad

    2015-12-01

    Nickel based Inconel-625 (IN625) metal matrix composites (MMCs) were prepared using pre-heated nickel phosphide (Ni-P) coated silicon carbide (SiC) reinforcement particles by Direct Metal Laser Sintering (DMLS) additive manufacturing process under inert nitrogen atmosphere to obtain interface influences on MMCs. The distribution of SiC particles and microstructures were characterized using optical and scanning electron micrographs, and the mechanical behaviours were thoroughly examined. The results clearly reveal that the interface integrity between the SiC particles and the IN625 matrix, the mixed powders flowability, the SiC ceramic particles and laser beam interaction, and the hardness, and tensile characteristics of the DMLS processed MMCs were improved effectively by the use of Ni-P coated SiC particles.

  1. Characterization of surface enhancement of carbon ion-implanted TiN coatings by metal vapor vacuum arc ion implantation

    CERN Document Server

    Chang, C L

    2002-01-01

    The modification of the surfaces of energetic carbon-implanted TiN films using metal vapor vacuum arc (MEVVA) ion implantation was investigated, by varying ion energy and dose. The microhardness, microstructure and chemical states of carbon, implanted on the surface layer of TiN films, were examined, as functions of ion energy and dose, by nanoindenter, transmission electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Results revealed that the microhardness increased from 16.8 up to 25.3 GPa and the friction coefficient decreased to approximately 0.2, depending on the implanted ion energy and dose. The result is attributed to the new microcrystalline phases of TiCN and TiC formed, and carbon concentration saturation of the implanted matrix can enhance the partial mechanical property of TiN films after MEVVA treatment. The concentration distribution, implantation depth and chemical states of carbon-implanted TiN coatings depended strongly on the ion dose and...

  2. Zinc phosphate conversion coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, Toshifumi (Wading River, NY)

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  3. Zinc phosphate conversion coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  4. Chitosan-doped-hybrid/TiO2 nanocomposite based sol-gel coating for the corrosion resistance of aluminum metal in 3.5% NaCl medium.

    Science.gov (United States)

    J, Balaji; M G, Sethuraman

    2017-11-01

    The study outlines the role of chitosan, a biopolymer on corrosion behavior of Hy/nano-TiO 2 based sol-gel coating over aluminum metal. In this study organic-inorganic hybrid sols were synthesized through hydrolysis and condensation of 3-glycidoxypropyltrimethoxy silane (GPTMS), tetraethoxysilane (TEOS) and titanium (IV) isopropoxide (TIP) in acidic solution. Chitosan was doped into sol-gel matrix and self-assembled over aluminum substrate. The resultant chitosan-doped-Hy/nano-TiO 2 sol-gel coating was characterized by Fourier Transform Infrared (FT-IR) spectra, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Energy-Dispersive X-ray Spectroscopy (EDX) analyses. The as-tailored aluminum substrate was evaluated for corrosion resistance in neutral medium. The protection ability of these coatings was evaluated by electrochemical impedance studies (EIS) and potentiodynamic polarization (PP) measurements in 3.5% NaCl medium. The EIS and PP results showed that chitosan-doped- Hy/nano-TiO 2 sol-gel coating exhibited better protection from corrosion than the undoped Hy/TiO 2 nanocomposite coating. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Exploring reverse shape selectivity and molecular sieving effect of metal-organic framework UIO-66 coated capillary column for gas chromatographic separation.

    Science.gov (United States)

    Chang, Na; Yan, Xiu-Ping

    2012-09-28

    Metal-organic frameworks (MOFs) which offer a variety of topologies, porous networks and high surface areas are promising and have potential for the applications of specific adsorption, isomerization, catalysis and separation. UIO-66 is the first MOF that has been observed to have reverse shape selectivity. However, such reverse shape selectivity of MOFs has never been explored for capillary gas chromatographic separation. Here we report the fabrication of MOF UIO-66 coated capillary column and exploration of the reverse shape selectivity and molecular sieving effect of such column for capillary gas chromatographic separation of alkane isomers and benzene homologues with excellent selectivity and precision. The adsorption enthalpies and entropies on the interaction between hydrocarbons and UIO-66 were measured to illustrate the energy effect on the separation of alkane isomers and benzene homologues on the UIO-66 coated capillary column. UIO-66 coated capillary column gave preferential retention of branched alkane isomers over their linear isomer, showing reverse shape selectivity, making UIO-66 coated capillary column attractive for capillary gas chromatographic separation of alkane isomers. iso-Propylbenzene (branched) eluted after n-propylbenzene on the UIO-66 coated capillary column again shows reverse shape selectivity. However, much bulkier 1,3,5-trimethylbenzene eluted earlier than n-propylbenzene and iso-propylbenzene on the UIO-66 coated capillary column, exhibiting molecular sieving effect. The combination of reverse shape selectivity with molecular sieving effect makes the UIO-66 coated capillary column promising for the separation of structural isomers. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Solution-Processed Metal Coating to Nonwoven Fabrics for Wearable Rechargeable Batteries.

    Science.gov (United States)

    Lee, Kyulin; Choi, Jin Hyeok; Lee, Hye Moon; Kim, Ki Jae; Choi, Jang Wook

    2017-12-27

    Wearable rechargeable batteries require electrode platforms that can withstand various physical motions, such as bending, folding, and twisting. To this end, conductive textiles and paper have been highlighted, as their porous structures can accommodate the stress built during various physical motions. However, fabrics with plain weaves or knit structures have been mostly adopted without exploration of nonwoven counterparts. Also, the integration of conductive materials, such as carbon or metal nanomaterials, to achieve sufficient conductivity as current collectors is not well-aligned with large-scale processing in terms of cost and quality control. Here, the superiority of nonwoven fabrics is reported in electrochemical performance and bending capability compared to currently dominant woven counterparts, due to smooth morphology near the fiber intersections and the homogeneous distribution of fibers. Moreover, solution-processed electroless deposition of aluminum and nickel-copper composite is adopted for cathodes and anodes, respectively, demonstrating the large-scale feasibility of conductive nonwoven platforms for wearable rechargeable batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Dissolution kinetics of metal coating in HNO3-scCO2 micro-emulsion using QCM

    International Nuclear Information System (INIS)

    Ju, Min Su; Koh, Moon Sung; Park, Kwang Heon; Kim, Hak Won; Kim, Hong Doo

    2005-01-01

    technique expands its application area to pressurized fluids such as liquids and supercritical CO 2 . In this study, we made a HNO 3 -scCO 2 microemulsion to remove a film from a contaminated metal surface. F-AOT and Proline surfactant-1 were used as a surfactant. HNO 3 was used as a acid solution for dissolution Cu coating. As a setting for experimental conditions, we analyzed the film removal characteristics of Cu and Ni coated QCM

  8. Characterization of the electrochemical behavior of coating by steel welding 308l and in presence of noble metals deposits; Caracterizacion del comportamiento electroquimico de recubrimiento por soldadura de acero 308L y en presencia de depositos de metales nobles

    Energy Technology Data Exchange (ETDEWEB)

    Piedras, P.; Arganis J, C. R., E-mail: pedro.piedras@hotmail.es [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    In this work the oxide deposits and noble metals deposit were characterized (Ag and Pt) on a coating of stainless steel 308l that were deposited by the shield metal arc welding (SMAW) on steel A36 by means of scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. The extrapolation of Tafel technique was also used to obtain the corrosion potential (Ec) for the pre-rusty steel and for the samples with deposits of Pt and Ag under conditions of hydrogen water chemistry (HWC), demonstrating that this parameter diminishes with the presence of this deposits. (Author)

  9. Features of copper coatings growth at high-rate deposition using magnetron sputtering systems with a liquid metal target

    Czech Academy of Sciences Publication Activity Database

    Bleykher, G.A.; Borduleva, A.O.; Yuryeva, A.V.; Krivobokov, V.P.; Lančok, Ján; Bulíř, Jiří; Drahokoupil, Jan; Klimša, Ladislav; Kopeček, Jaromír; Fekete, Ladislav; Čtvrtlík, Radim; Tomáštík, Jan

    2017-01-01

    Roč. 324, Sep (2017), s. 111-120 ISSN 0257-8972 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : magnetron sputtering * evaporation * high-rate coating deposition * coating properties * Cu coatings Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.589, year: 2016

  10. Non-metallic coating thickness prediction using artificial neural network and support vector machine with time resolved thermography

    Science.gov (United States)

    Wang, Hongjin; Hsieh, Sheng-Jen; Peng, Bo; Zhou, Xunfei

    2016-07-01

    A method without requirements on knowledge about thermal properties of coatings or those of substrates will be interested in the industrial application. Supervised machine learning regressions may provide possible solution to the problem. This paper compares the performances of two regression models (artificial neural networks (ANN) and support vector machines for regression (SVM)) with respect to coating thickness estimations made based on surface temperature increments collected via time resolved thermography. We describe SVM roles in coating thickness prediction. Non-dimensional analyses are conducted to illustrate the effects of coating thicknesses and various factors on surface temperature increments. It's theoretically possible to correlate coating thickness with surface increment. Based on the analyses, the laser power is selected in such a way: during the heating, the temperature increment is high enough to determine the coating thickness variance but low enough to avoid surface melting. Sixty-one pain-coated samples with coating thicknesses varying from 63.5 μm to 571 μm are used to train models. Hyper-parameters of the models are optimized by 10-folder cross validation. Another 28 sets of data are then collected to test the performance of the three methods. The study shows that SVM can provide reliable predictions of unknown data, due to its deterministic characteristics, and it works well when used for a small input data group. The SVM model generates more accurate coating thickness estimates than the ANN model.

  11. Unlubricated Gross Slip Fretting Wear of Metallic Plasma Sprayed Coatings for Ti6A14V Surfaces

    National Research Council Canada - National Science Library

    Hager, Jr., Carl H; Sanders, Jeffrey H; Sharma, Shashi K

    2006-01-01

    .... The combination of scanning electron microscopy (SEM), surface profilometry, surface chemistry (EDS), and friction analysis were used to study coating performance and evaluate the interfacial wear mechanisms...

  12. Nanostructured Metal Oxide Coatings for Electrochemical Energy Conversion and Storage Electrodes

    Science.gov (United States)

    Cordova, Isvar Abraxas

    supercapacitor electrode to reach a capacitance of 640 F/g, under MnO2 specific mass loading conditions (2.3 mg/cm2) that are higher than previously reported. In the second engineered nanoarchitecture, the electrochemical energy storage properties of a transparent electrode based on a network of solution-processed Cu/Ni cores/shell nanowires (NWs) were activated by electrochemically converting the Ni metal shell into Ni(OH)2. Furthermore, an adjustment of the molar percentage of Ni plated onto the Cu NWs was found to result in a tradeoff between capacitance, transmittance, and stability of the resulting nickel hydroxide-based electrode. The nominal area capacitance and power performance results obtained for this Cu/Ni(OH)2 transparent electrode demonstrates that it has significant potential as a hybrid supercapacitor electrode for integration into cutting edge flexible and transparent electronic devices.

  13. Examination of Hybrid Metal Coatings for Mitigation of Fission Product Release and Corrosion Protection of LWR SiC/SiC

    Energy Technology Data Exchange (ETDEWEB)

    Ang, Caen K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burns, Joseph R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    There is a need to increase the safety margins of current and future light water reactors (LWRs) due to the unfortunate events at Fukushima Daiichi Nuclear Plant. Safety is crucial to restore public confidence in nuclear energy, acknowledged as an economical, high-­density energy solution to climate change. The development of accident-­tolerant fuel (ATF) concepts is crucial to this endeavor. The objective of ATF is to delay the consequences of accident progression, being inset in high temperature steam and maintaining high thermomechanical strength for radionuclide retention. The use of advanced SiCf-­SiC composite as a substitute for zircaloy-­based cladding is being considered. However, at normal operations, SiC is vulnerable to the reactor coolant and may corrode at an unacceptable rate. As a ceramic-­matrix composite material, it is likely to undergo microcracking operation, which may compromise the ability to contain gaseous fission products. A proposed solution to both issues is the application of mitigation coatings for use in normal operations. At Oak Ridge National Laboratory (ORNL), three coating technologies have been investigated with industry collaborators and vendors. These are electrochemical deposition, cathodic arc physical vapor deposition (PVD hereafter) and vacuum plasma spray (VPS). The objective of this document is to summarize these processing technologies, the resultant as-­processed microstructures and properties of the coatings. In all processes, substrate constraint resulted in substantial tensile stresses within the coating layer. Each technology must mitigate this tensile stress. Electrochemical coatings use chromium as the coolant facing material, and are deposited on a nickel or carbon “bond coat”. This is economical but suffers microcracking in the chromium layer. PVD-­based coatings use chromium and titanium in both metallic form and nitrides, and can be deposited defense-­in-­depth as multilayers. This vapor method

  14. fM to aM nucleic acid amplification for molecular diagnostics in a non-stick-coated metal microfluidic bioreactor

    Science.gov (United States)

    Huang, Guoliang; Huang, Qin; Ma, Li; Luo, Xianbo; Pang, Biao; Zhang, Zhixin; Wang, Ruliang; Zhang, Junqi; Li, Qi; Fu, Rongxin; Ye, Jiancheng

    2014-01-01

    A sensitive DNA isothermal amplification method for the detection of DNA at fM to aM concentrations for pathogen identification was developed using a non-stick-coated metal microfluidic bioreactor. A portable confocal optical detector was utilized to monitor the DNA amplification in micro- to nanoliter reaction assays in real-time, with fluorescence collection near the optical diffraction limit. The non-stick-coated metal microfluidic bioreactor, with a surface contact angle of 103°, was largely inert to bio-molecules, and DNA amplification could be performed in a minimum reaction volume of 40 nL. The isothermal nucleic acid amplification for Mycoplasma pneumoniae identification in the non-stick-coated microfluidic bioreactor could be performed at a minimum DNA template concentration of 1.3 aM, and a detection limit of three copies of genomic DNA was obtained. This microfluidic bioreactor offers a promising clinically relevant pathogen molecular diagnostic method via the amplification of targets from only a few copies of genomic DNA from a single bacterium. PMID:25475544

  15. The Study of Corrosion and Wear Resistance of Copper Composite Coatings with Inclusions of Carbon Nanomaterials in the Copper Metal Matrix

    Directory of Open Access Journals (Sweden)

    Viktorija MEDELIENĖ

    2011-07-01

    Full Text Available This paper deals with the peculiarities of the behaviour of copper nanocomposite coatings with CNMs inclusions under the free corrosion conditions in the acidic medium. The parameters of corrosion current density (jcorr, anodic dissolution current density (ia and polarization resistance (Rp have been determined. In the acidic medium a stronger oxidation of nanostructured copper nanocomposites occurred. With longer immersion periods more corrosion products are formed, resulting in a increase in the polarization resistance (Rp of corrosion. Corrosion products cover the whole surface of the coatings and the corrosion rate (jcorr tends towards a steady value of 1.7×10-3 ¸ 2.1×10-3 A·cm-2 for all copper coatings studied: 1.7×10-3 A·cm-2 for both Cu and Cu-CNM1, 1.9×10-3 A·cm-2 - for Cu-CNM2 and 2.1×10-3 A·cm-2 - for Cu-CNM3 composite coatings. It has been established that nanocomposites possess a higher wear resistance as compared to that of pure copper. The damage of metal characterized as a depth scar (đ is lower. The roughness of the composites studied was found to be the essential factor affecting their wear resistance. Therefore, the wear resistance of nanocomposites is impaired when they are deposited on a hard steel substrate.http://dx.doi.org/10.5755/j01.ms.17.2.481

  16. Arsenic Removal from Aqueous Solution Using Pure and Metal-Doped Titania Nanoparticles Coated on Glass Beads: Adsorption and Column Studies

    Directory of Open Access Journals (Sweden)

    M. Ihsan Danish

    2013-01-01

    Full Text Available Nanosized metal oxide, Titania, provides high surface area and specific affinity for the adsorption of heavy metals, including arsenic (As, which is posing a great threat to the world population due to its carcinogenic nature. In this study, As(III adsorption was studied on pure and metal- (Ag- and Fe- doped Titania nanoparticles. The nanoparticles were synthesized by liquid impregnation method with some modifications, with crystallite size in the range of 30 to 40 nm. Band gap analysis, using Kubelka-Munk function showed a shift of absorption band from UV to visible region for the metal-doped Titania. Effect of operational parameters like dose of nanoparticles, initial As(III concentration, and pH was evaluated at 25°C. The data obtained gave a good fit with Langmuir and Freundlich isotherms and the adsorption was found to conform to pseudo-second-order kinetics. In batch studies, over 90% of arsenic removal was observed for both types of metal-doped Titania nanoparticles from a solution containing up to 2 ppm of the heavy metal. Fixed bed columns of nanoparticles, coated on glass beads, were used for As(III removal under different operating conditions. Thomas and Yoon-Nelson models were applied to predict the breakthrough curves and to find the characteristic column parameters useful for process design. The columns were regenerated using 10% NaOH solution.

  17. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  18. Persistent cyclestability of carbon coated Zn–Sn metal oxide/carbon microspheres as highly reversible anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Fang, Guoqing; Kaneko, Shingo; Liu, Weiwei; Xia, Bingbo; Sun, Hongdan; Zhang, Ruixue; Zheng, Junwei; Li, Decheng

    2013-01-01

    Development of high-capacity anode materials equipped with strong cyclestability is a great challenge for use as practical electrode for high-performance lithium-ion rechargeable battery. In this study, we synthesized a carbon coated Zn–Sn metal nanocomposite oxide and carbon spheres (ZTO@C/CSs) via a simple glucose hydrothermal reaction and subsequent carbonization approach. The carbon coated ZTO/carbon microspheres composite maintained a reversible capacity of 680 mAh g −1 after 345 cycles at a current density of 100 mA g −1 , and furthermore the cell based on the composite exhibited an excellent rate capability of 470 mAh g −1 even when the cell was cycled at 2000 mA g –1 . The thick carbon layer formed on the ZTO nanoparticles and carbon spheres effectively buffered the volumetric change of the particles, which thus prolonged the cycling performance of the electrodes

  19. Cadmium(II)-based metal-organic nanotubes as solid-phase microextraction coating for ultratrace-level analysis of polychlorinated biphenyls in seawater samples.

    Science.gov (United States)

    Sheng, Wan-Ru; Chen, Yue; Wang, Shan-Shan; Wang, Xiao-Li; Wang, Ming-Lin; Zhao, Ru-Song

    2016-11-01

    In this study, stable cadmium(II)-based metal-organic nanotubes (Cd-MONTs) were prepared and used as a coating material for solid-phase microextraction (SPME) of polychlorinated biphenyls (PCBs) from environmental water samples. The as-prepared Cd-MONT SPME coating material was characterized by thermal gravimetric analysis, scanning electron microscopy, and X-ray diffraction. The synthesized Cd-MONTs exhibited high thermal stability (385 °C) and excellent extraction performance toward PCBs. The important conditions were optimized systematically by the response surface method. Under the optimal conditions, the new fiber achieved high enrichment factors (938-3417), low limits of detection (1.80-8.73 pg L -1 ), and wide linearity (10-5000 pg L -1 ). The method developed was used in ultratrace-level analysis of PCBs in seawater samples, with satisfactory results for each sample.

  20. HIGHWAY INFRASTRUCTURE FOCUS AREA NEXT-GENERATION INFRASTRUCTURE MATERIALS VOLUME I - TECHNICAL PROPOSAL & MANAGEMENTENHANCEMENT OF TRANSPORTATION INFRASTRUCTURE WITH IRON-BASED AMORPHOUS-METAL AND CERAMIC COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C

    2007-12-04

    The infrastructure for transportation in the United States allows for a high level of mobility and freight activity for the current population of 300 million residents, and several million business establishments. According to a Department of Transportation study, more than 230 million motor vehicles, ships, airplanes, and railroads cars were used on 6.4 million kilometers (4 million miles) of highways, railroads, airports, and waterways in 1998. Pipelines and storage tanks were considered to be part of this deteriorating infrastructure. The annual direct cost of corrosion in the infrastructure category was estimated to be approximately $22.6 billion in 1998. There were 583,000 bridges in the United States in 1998. Of this total, 200,000 bridges were steel, 235,000 were conventional reinforced concrete, 108,000 bridges were constructed using pre-stressed concrete, and the balance was made using other materials of construction. Approximately 15 percent of the bridges accounted for at this point in time were structurally deficient, primarily due to corrosion of steel and steel reinforcement. Iron-based amorphous metals, including SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been developed, and have very good corrosion resistance. These materials have been prepared as a melt-spun ribbons, as well as gas atomized powders and thermal-spray coatings. During electrochemical testing in several environments, including seawater at 90 C, the passive film stabilities of these materials were found to be comparable to that of more expensive high-performance alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. These materials also performed very well in standard salt fog tests. Chromium (Cr), molybdenum (Mo) and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation

  1. Structural characterization of the metal/glass interface in bioactive glass coatings on Ti-6Al-4V

    Energy Technology Data Exchange (ETDEWEB)

    Oku, T.; Suganuma, K.; Wallemberg, L.R.; Tomsia, A.P.; Gomez-Vega, J.M.; Saiz, E.

    1999-12-01

    Coating Ti-based implants with bioactive materials promotes joining between the prostheses and the bone as well as increasing long-term implant stability. In the present work, the interface between Ti-6Al-4V and bioactive silicate glass coatings, prepared using a simple enameling technique, is analyzed. High-resolution transmission electron microscopy of the glass/alloy interface shows the formation of a reaction layer ({approx}150 nm thick) composed of Ti5Si3 nanoparticles with a size of {approx}20 nm. This nanostructured interface facilitates the formation of a stable joint between the glass coating and the alloy.

  2. Influence of Thickness of Multilayered Nano-Structured Coatings Ti-TiN-(TiCrAlN and Zr-ZrN-(ZrCrNbAlN on Tool Life of Metal Cutting Tools at Various Cutting Speeds

    Directory of Open Access Journals (Sweden)

    Alexey Vereschaka

    2018-01-01

    Full Text Available This paper considers the influence of thickness of multilayered nano-structured coatings Ti-TiN-(TiCrAlN and Zr-ZrN-(ZrCrNbAlN on tool life of metal cutting tools at various cutting speeds (vc = 250, 300, 350 and 400 m·min−1. The paper investigates the basic mechanical parameters of coatings and the mechanism of coating failure in scratch testing depending on thickness of coating. Cutting tests were conducted in longitudinal turning of steel C45 with tools with the coatings under study of various thicknesses (3, 5, and 7 µm, with an uncoated tool and with a tool with a “reference” coating of TiAlN. The relationship of “cutting speed vc—tool life T” was built and investigated; and the mechanisms were found to determine the selection of the optimum coating thickness at various cutting speeds. Advantages of cutting tools with these coatings are especially obvious at high cutting speeds (in particular, vc = 400 m·min−1. If at lower cutting speeds, the longest tool life is shown by tools with thicker coatings (of about 7 μm, then with an increase in cutting speed (especially at vc = 400 m·min−1 the longest tool life is shown by tools with thinner coating (of about 3 μm.

  3. Cytokine induction of sol–gel-derived TiO2 and SiO2 coatings on metallic substrates after implantation to rat femur

    Science.gov (United States)

    Urbanski, Wiktor; Marycz, Krzysztof; Krzak, Justyna; Pezowicz, Celina; Dragan, Szymon Feliks

    2017-01-01

    Material surface is a key determinant of host response on implanted biomaterial. Therefore, modification of the implant surface may optimize implant–tissue reactions. Inflammatory reaction is inevitable after biomaterial implantation, but prolonged inflammation may lead to adverse reactions and subsequent implant failure. Proinflammatory activities of cytokines like interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha (TNF-α) are attractive indicators of these processes and ultimately characterize biocompatibility. The objective of the study was to evaluate local cytokine production after implantation of stainless steel 316L (SS) and titanium alloy (Ti6Al4V) biomaterials coated with titanium dioxide (TiO2) and silica (SiO2) coatings prepared by sol–gel method. Biomaterials were implanted into rat femur and after 12 weeks, bones were harvested. Bone–implant tissue interface was evaluated; immunohistochemical staining was performed to identify IL-6, TNF-α, and Caspase-1. Histomorphometry (AxioVision Rel. 4.6.3 software) of tissue samples was performed in order to quantify the cytokine levels. Both the oxide coatings on SS and Ti6Al4V significantly reduced cytokine production. However, the lowest cytokine levels were observed in TiO2 groups. Cytokine content in uncoated groups was lower in Ti6Al4V than in SS, although coating of either metal reduced cytokine production to similar levels. Sol–gel TiO2 or SiO2 coatings reduced significantly the production of proinflammatory cytokines by local tissues, irrespective of the material used as a substrate, that is, either Ti6Al4V or SS. This suggests lower inflammatory response, which directly points out improvement of materials’ biocompatibility. PMID:28280331

  4. The Performance of Chrome-Coated Copper as Metallic Catalytic Converter to Reduce Exhaust Gas Emissions from Spark-Ignition Engine

    Science.gov (United States)

    Warju; Harto, S. P.; Soenarto

    2018-01-01

    One of the automotive technologies to reduce exhaust gas emissions from the spark-ignition engine (SIE) is by using a catalytic converter. The aims of this research are firstly to conduct a metallic catalytic converter, secondly to find out to what extend chrome-coated copper plate (Cu+Cr) as a catalyst is efficient. To measure the concentration of carbon monoxide (CO) and hydrocarbon (HC) on the frame there are two conditions required. First is when the standard condition, and second is when Cu+Cr metallic catalytic converter is applied using exhaust gas analyzer. Exhaust gas emissions from SIE are measured by using SNI 19-7118.1-2005. The testing of CO and HC emissions were conducted with variable speed to find the trend of exhaust gas emissions from idle speed to high speed. This experiment results in the fact that the use of Cu+Cr metallic catalytic converter can reduce the production of CO and HC of a four-stroke gasoline engine. The reduction of CO and HC emission are 95,35% and 79,28%. Using active metal catalyst in form of metallic catalytic converter, it is gained an optimum effective surface of a catalyst which finally is able to decrease the amount of CO and HC emission significantly in every spinning happened in the engine. Finally, this technology can be applied to the spark ignition engine both car and motorcycle to support blue sky program in Indonesia.

  5. Unlubricated Gross Slip Fretting Wear of Metallic Plasma Sprayed Coatings for Ti6A14V Surfaces

    National Research Council Canada - National Science Library

    Hager, Jr., Carl H; Sanders, Jeffrey H; Sharma, Shashi K

    2006-01-01

    ... to simulate cold engine startup. Alternative coatings such as plasma sprayed molybdenum and nickel were also evaluated because of their potential for reducing fretting wear under certain simulated engine conditions...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-15

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

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

    Science.gov (United States)

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

    2016-07-01

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

  8. Development and characterization of protective nickel coatings by CVD process for non-ferrous metals and alloys

    International Nuclear Information System (INIS)

    Haq, A.U.

    2012-01-01

    Objective of this thesis is the formation of adhesive and corrosion resistant nickel film on aluminum, aluminum-lithium (Li 0.5 %) alloy and copper substrates by chemical vapor deposition (CVD) technique. Different surface preparation treatments such as electropolishing, anodizing and pickling are applied to the aforementioned substrates and its effect on the adhesion and corrosion resistance of nickel coating is studied. Nickel coating is deposited on different substrates by using already optimized parameters of 190-200 degree C deposition temperature, 9-8 x 10/sup -1/ Torr pressure during deposition, pure nickel-tetra-carbonyl gas, and induction heating source and 5 minutes deposition time. Substrates subjected to pickling treatment show excellent adhesion of nickel coating with a value of 5B based on ASTM standard while electropolished substrates show valve of 3B. XRD characterization of the nickel film show characteristic peaks of nickel confirming its phase purity. The SEM images show that nickel coating follows the surface features of the substrate. The pickled surface results in film with rough morphology than electropolished or anodized surface. The corrosion resistance of both uncoated and coated substrates is studied by monitoring its open circuit potential in different electrolytes (brine solution, sea and distilled water) at different temperatures. All substrates coated with nickel show 120-400mV potential difference compare with uncoated substrates in different electrolytes. (author)

  9. Prospective, multi-center evaluation of a silicon carbide coated cobalt chromium bare metal stent for percutaneous coronary interventions: Two-year results of the ENERGY Registry

    Energy Technology Data Exchange (ETDEWEB)

    Erbel, Raimund, E-mail: erbel@uk-essen.de [Department of Cardiology, University of Duisburg-Essen, Essen (Germany); Eggebrecht, Holger [Cardioangiological Center Bethanien (CCB), Frankfurt (Germany); Roguin, Ariel [Department of Cardiology, Rambam Medical Center, Haifa (Israel); Schroeder, Erwin [Division of Cardiovascular Medicine, Cliniques Universitaires de Mont-Godinne, Yvoir (Belgium); Philipp, Sebastian [Department Internal Medicine/Cardiology, Elbe Klinikum Stade, Stade (Germany); Heitzer, Thomas [Department of Cardiology, Heart Center Dortmund, Dortmund (Germany); Schwacke, Harald [Department of Internal Medicine, Diakonissen-Stiftungs- Krankenhaus Speyer (Germany); Ayzenberg, Oded [The Heart Institute, Kaplan Medical Center, Rehovot (Israel); Serra, Antonio [Servicio de Cardiología, Hospital de la Santa Creu i Sant Pau, Barcelona, España (Spain); Delarche, Nicolas [Cardiology unit, Pau General Hospital, Pau (France); Luchner, Andreas [Department of Internal Medicine/Cardiology, Universitätsklinikum Regensburg (Germany); Slagboom, Ton [Department of Cardiology, Onze Lieve Vrouwe Gasthuis, Amsterdam (Netherlands)

    2014-11-15

    Background: Novel bare metal stents with improved stent design may become a viable alternative to drug-eluting stents in certain patient groups, particularly, when long-term dual antiplatelet therapy should be avoided. Purpose: The ENERGY registry aimed to assess the safety and benefits of a cobalt–chromium thin strut bare metal stent with a passive coating in a large series of patients under real-world conditions. Methods and materials: This prospective registry recruited 1016 patients with 1074 lesions in 48 centers from April to November 2010. The primary endpoint was the rate of major adverse cardiac events (MACEs), a composite of cardiac death, myocardial infarction and clinically driven target lesion revascularization. Results: More than half of the lesions (61.0%) were type A/B1 lesions, mean lesion length was 14.5 ± 6.5 mm and mean reference vessel diameter 3.2 ± 0.5 mm. MACE rates at 6, 12 and 24 months were 4.9%, 8.1% and 9.4%, target lesion revascularization rates 2.8%, 4.9% and 5.4% and definite stent thrombosis rates 0.5%, 0.6% and 0.6%. Subgroups showed significant differences in baseline and procedural characteristics which did not translate into significantly different clinical outcomes. Specifically, MACE rates at 24 months were 13.5% in diabetics, 8.6% in small stents and 9.6% in acute coronary syndrome patients. Conclusion: The population of ENERGY reflects real-world conditions with bare metal stents being mainly used in simple lesions. In this setting, percutaneous coronary intervention using a cobalt–chromium thin strut bare metal stent with a passive coating showed very good results up to 24 months. (ClinicalTrials.gov:NCT01056120) Summary for annotated table of contents: The ENERGY international registry evaluated the safety and benefits of a cobalt–chromium thin strut bare metal stent with passive coating in 1016 patients under real-world conditions until 2 years. Results were encouraging with a low composite rate of cardiac death

  10. Prospective, multi-center evaluation of a silicon carbide coated cobalt chromium bare metal stent for percutaneous coronary interventions: Two-year results of the ENERGY Registry

    International Nuclear Information System (INIS)

    Erbel, Raimund; Eggebrecht, Holger; Roguin, Ariel; Schroeder, Erwin; Philipp, Sebastian; Heitzer, Thomas; Schwacke, Harald; Ayzenberg, Oded; Serra, Antonio; Delarche, Nicolas; Luchner, Andreas; Slagboom, Ton

    2014-01-01

    Background: Novel bare metal stents with improved stent design may become a viable alternative to drug-eluting stents in certain patient groups, particularly, when long-term dual antiplatelet therapy should be avoided. Purpose: The ENERGY registry aimed to assess the safety and benefits of a cobalt–chromium thin strut bare metal stent with a passive coating in a large series of patients under real-world conditions. Methods and materials: This prospective registry recruited 1016 patients with 1074 lesions in 48 centers from April to November 2010. The primary endpoint was the rate of major adverse cardiac events (MACEs), a composite of cardiac death, myocardial infarction and clinically driven target lesion revascularization. Results: More than half of the lesions (61.0%) were type A/B1 lesions, mean lesion length was 14.5 ± 6.5 mm and mean reference vessel diameter 3.2 ± 0.5 mm. MACE rates at 6, 12 and 24 months were 4.9%, 8.1% and 9.4%, target lesion revascularization rates 2.8%, 4.9% and 5.4% and definite stent thrombosis rates 0.5%, 0.6% and 0.6%. Subgroups showed significant differences in baseline and procedural characteristics which did not translate into significantly different clinical outcomes. Specifically, MACE rates at 24 months were 13.5% in diabetics, 8.6% in small stents and 9.6% in acute coronary syndrome patients. Conclusion: The population of ENERGY reflects real-world conditions with bare metal stents being mainly used in simple lesions. In this setting, percutaneous coronary intervention using a cobalt–chromium thin strut bare metal stent with a passive coating showed very good results up to 24 months. (ClinicalTrials.gov:NCT01056120) Summary for annotated table of contents: The ENERGY international registry evaluated the safety and benefits of a cobalt–chromium thin strut bare metal stent with passive coating in 1016 patients under real-world conditions until 2 years. Results were encouraging with a low composite rate of cardiac death

  11. Electrochemical and morphological investigation of silver and zinc modified calcium phosphate bioceramic coatings on metallic implant materials

    International Nuclear Information System (INIS)

    Furko, M.; Jiang, Y.; Wilkins, T.A.; Balázsi, C.

    2016-01-01

    In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70 °C from electrolyte containing the appropriate amount of Ca(NO 3 ) 2 and NH 4 H 2 PO 4 components. During the electrochemical deposition Ag + and Zn 2+ ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringer's solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn 2+ is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements. - Highlights: • Ag and Zn doped calcium phosphate (CaP) layers were electrochemically deposited. • Layer degradation was studied by EIS and potentiodynamic measurements. • The bioceramic coatings became passive after a period of immersion time. • Ag and Zn modified layer shows higher degradation rate compared to pure CaP coating.

  12. Electrochemical and morphological investigation of silver and zinc modified calcium phosphate bioceramic coatings on metallic implant materials

    Energy Technology Data Exchange (ETDEWEB)

    Furko, M., E-mail: monika.furko@bayzoltan.hu [Bay Zoltán Nonprofit Ltd. for Applied Research, H-1116 Budapest, Fehérvári u. 130 (Hungary); Jiang, Y.; Wilkins, T.A. [Institute of Particle Science and Engineering, University of Leeds, LS2 9JT (United Kingdom); Balázsi, C. [Bay Zoltán Nonprofit Ltd. for Applied Research, H-1116 Budapest, Fehérvári u. 130 (Hungary)

    2016-05-01

    In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70 °C from electrolyte containing the appropriate amount of Ca(NO{sub 3}){sub 2} and NH{sub 4}H{sub 2}PO{sub 4} components. During the electrochemical deposition Ag{sup +} and Zn{sup 2+} ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringer's solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn{sup 2+} is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements. - Highlights: • Ag and Zn doped calcium phosphate (CaP) layers were electrochemically deposited. • Layer degradation was studied by EIS and potentiodynamic measurements. • The bioceramic coatings became passive after a period of immersion time. • Ag and Zn modified layer shows higher degradation rate compared to pure CaP coating.

  13. Tungsten-coated nano-boron carbide as a non-noble metal bifunctional electrocatalyst for oxygen evolution and hydrogen evolution reactions in alkaline media.

    Science.gov (United States)

    Zhang, Yan; Wang, Yanhui; Han, Chan; Jia, Shaopei; Zhou, Shuyu; Zang, Jianbing

    2017-12-14

    Herein, tungsten-coated nano-boron carbide (W-WB 4 -WC x /B 4 C) particles were prepared by heating a mixture of B 4 C and W powder using a spark plasma coating (SPC) method. During the discharge treatment process, metal W in the mixture is activated and reacts with B 4 C to form WC x , WB 4 , and graphite nanoribbons. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance of W-WB 4 -WC x /B 4 C is tested in an alkaline solution, and the results show that the W-WB 4 -WC x /B 4 C composite electrocatalyst exhibits a low overpotential of 0.36 V at 10 mA cm -2 for the OER, a small overpotential of -0.19 V (j = 10 mA cm -2 ) for the HER, as well as good stability. The significantly enhanced electrocatalytic performance of the W-WB 4 -WC x /B 4 C composites is attributed to their unique structure, in which WC x and WB 4 not only improve the catalytic activity for the OER and HER, but also effectively anchor the W coating on the substrate.

  14. Development of graded Ni-YSZ composite coating on Alloy 690 by Pulsed Laser Deposition technique to reduce hazardous metallic nuclear waste inventory.

    Science.gov (United States)

    Sengupta, Pranesh; Rogalla, Detlef; Becker, Hans Werner; Dey, Gautam Kumar; Chakraborty, Sumit

    2011-08-15

    Alloy 690 based 'nuclear waste vitrification furnace' components degrade prematurely due to molten glass-alloy interactions at high temperatures and thereby increase the volume of metallic nuclear waste. In order to reduce the waste inventory, compositionally graded Ni-YSZ (Y(2)O(3) stabilized ZrO(2)) composite coating has been developed on Alloy 690 using Pulsed Laser Deposition technique. Five different thin-films starting with Ni80YSZ20 (Ni 80 wt%+YSZ 20 wt%), through Ni60YSZ40 (Ni 60 wt%+YSZ 40 wt%), Ni40YSZ60 (Ni 40 wt%+YSZ 60 wt%), Ni20YSZ80 (Ni 20 wt%+YSZ 80 wt%) and Ni0YSZ100 (Ni 0 wt%+YSZ 100 wt%), were deposited successively on Alloy 690 coupons. Detailed analyses of the thin-films identify them as homogeneous, uniform, pore free and crystalline in nature. A comparative study of coated and uncoated Alloy 690 coupons, exposed to sodium borosilicate melt at 1000°C for 1-6h suggests that the graded composite coating could substantially reduced the chemical interactions between Alloy 690 and borosilicate melt. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Magnetic silica-coated sub-microspheres with immobilized metal ions for the selective removal of bovine hemoglobin from bovine blood.

    Science.gov (United States)

    Zhang, Min; Cheng, Dan; He, Xiwen; Chen, Langxing; Zhang, Yukui

    2010-06-01

    Magnetic silica-coated magnetite (Fe(3)O(4)) sub-microspheres with immobilized metal-affinity ligands are prepared for protein adsorption. First, magnetite sub-microspheres were synthesized by a hydrothermal method. Then silica was coated on the surface of Fe(3)O(4) particles using a sol-gel method to obtain magnetic silica sub-microspheres with core-shell morphology. Next, the trichloro(4-chloromethylphenyl) silane was immobilized on them, reacted with iminodiacetic acid (IDA), and charged with Cu(2+). The obtained magnetic silica sub-microspheres with immobilized Cu(2+) were applied for the absorption of bovine hemoglobin (BHb) and the removal of BHb from bovine blood. The size, morphology, and magnetic properties of the resulting magnetic micro(nano) spheres were investigated by using scanning microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and a vibrating sample magnetometer (VSM). The measurements showed that the magnetic sub-microspheres are spherical in shape, very uniform in size with a core-shell, and are almost superparamagnetic. The saturation magnetization of silica-coated magnetite (Fe(3)O(4)) sub-microspheres reached about 33 emu g(-1). Protein adsorption results showed that the sub-microspheres had a high adsorption capacity for BHb (418.6 mg g(-1)), low nonspecific adsorption, and good removal of BHb from bovine blood. This opens a novel route for future applications in removing abundant proteins in proteomic analysis.

  16. Deposition, structure, physical and invitro characteristics of Ag-doped β-Ca3(PO4)2/chitosan hybrid composite coatings on Titanium metal.

    Science.gov (United States)

    Singh, Ram Kishore; Awasthi, Sharad; Dhayalan, Arunkumar; Ferreira, J M F; Kannan, S

    2016-05-01

    Pure and five silver-doped (0-5Ag) β-tricalcium phosphate [β-TCP, β-Ca3(PO4)2]/chitosan composite coatings were deposited on Titanium (Ti) substrates and their properties that are relevant for applications in hard tissue replacements were assessed. Silver, β-TCP and chitosan were combined to profit from their salient and complementary antibacterial and biocompatible features.The β-Ca3(PO4)2 powders were synthesized by co-precipitation. The characterization results confirmed the Ag(+) occupancy at the crystal lattice of β-Ca3(PO4)2. The Ag-dopedβ-Ca3(PO4)2/chitosan composite coatings deposited by electrophoresis showed good antibacterial activity and exhibited negative cytotoxic effects towards the human osteosarcoma cell line MG-63. The morphology of the coatings was observed by SEM and their efficiency against corrosion of metallic substrates was determined through potentiodynamic polarization tests. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Metallurgical coating system

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, L.C.; Whittaker, G.S.

    1984-05-01

    The present invention relates to a novel metallurgical coating system which provides corrosion resistance and non-stick properties to metallic components which are subjected to unusually severe operating conditions. The coating system comprises a first layer comprising tantalum which is deposited upon a substrate and a second layer comprising molybdenum disilicide which is deposited upon the first layer.

  18. Cytokine induction of sol–gel-derived TiO2 and SiO2 coatings on metallic substrates after implantation to rat femur

    Directory of Open Access Journals (Sweden)

    Urbanski W

    2017-02-01

    Full Text Available Wiktor Urbanski,1 Krzysztof Marycz,2 Justyna Krzak,3 Celina Pezowicz,4 Szymon Feliks Dragan1 1Department of Orthopaedic Surgery and Traumatology, Wroclaw University Hospital, 2Electron Microscope Laboratory, Wroclaw University of Environmental and Life Sciences, 3Institute of Materials Science and Applied Mechanics, 4Division of Biomedical Engineering and Experimental Mechanics, Wroclaw University of Technology, Wroclaw, Poland Abstract: Material surface is a key determinant of host response on implanted biomaterial. Therefore, modification of the implant surface may optimize implant–tissue reactions. Inflammatory reaction is inevitable after biomaterial implantation, but prolonged inflammation may lead to adverse reactions and subsequent implant failure. Proinflammatory activities of cytokines like interleukin (IL-1, IL-6, and tumor necrosis factor-alpha (TNF-α are attractive indicators of these processes and ultimately characterize biocompatibility. The objective of the study was to evaluate local cytokine production after implantation of stainless steel 316L (SS and titanium alloy (Ti6Al4V biomaterials coated with titanium dioxide (TiO2 and silica (SiO2 coatings prepared by sol–gel method. Biomaterials were implanted into rat femur and after 12 weeks, bones were harvested. Bone–implant tissue interface was evaluated; immunohistochemical staining was performed to identify IL-6, TNF-α, and Caspase-1. Histomorphometry (AxioVision Rel. 4.6.3 software of tissue samples was performed in order to quantify the cytokine levels. Both the oxide coatings on SS and Ti6Al4V significantly reduced cytokine production. However, the lowest cytokine levels were observed in TiO2 groups. Cytokine content in uncoated groups was lower in Ti6Al4V than in SS, although coating of either metal reduced cytokine production to similar levels. Sol–gel TiO2 or SiO2 coatings reduced significantly the production of proinflammatory cytokines by local tissues

  19. Evaluation of HVOF coatings

    Directory of Open Access Journals (Sweden)

    Mariana Landová

    2016-07-01

    Full Text Available Attention in this paper is devoted to the evaluation of wear coatings deposited using HVOF technology (high velocity oxy-fuel. There were evaluated three types of coatings based on WC-Co (next only 1343, WC-Co-Cr (next only 1350 and Cr3C2-25NiCr (next only 1375. There was assessed adherence of coatings, micro hardness, porosity and the tribological properties of erosive, abrasive, adhesive and wear resistance of coatings in terms of cyclic thermal load. Thanks to wide variety of suitable materials and their combinations, the area of utilization thermally sprayed coatings is very broad. It is possible to deposit coatings of various materials from pure metals to special alloys. The best results in the evaluated properties were achieved at the coating with the label 1375.

  20. Study of the mechanical properties of single- layer and multi-layer metallic coatings with protective-decorative applications

    Directory of Open Access Journals (Sweden)

    Cherneva Sabina

    2018-01-01

    Full Text Available Single thin coating of matt nickel (Nimat, a mirror bright copper (Cubright, a mirror bright nickel (Nibright and their combinations were electrochemically deposited on brass substrate with thickness 500 μm. The basic aim was electrodeposition of two-layer Cubright/Nimat and Nibright/Cubright systems, and three-layer Nibright Cubrigh/Nimat system, which are among the most widely applied protective and decorative systems in light and medium operating conditions of corrosion. The thicknesses of the obtained films varied from 1 μm to 3.25 μm. They were investigated via nanoindentation experiments, in order to characterize their basic physical and mechanical characteristics, related with their good adhesion and corrosion protective ability, as well as ensuring the integrity of the system “protective coating/substrate” to possible mechanical, dynamic and/or thermal stresses. As a result, load-displacement curves were obtained and indentation hardness and indentation modulus were calculated using the Oliver & Pharr approximation method. The dependence of the indentation modulus and the indentation hardness on the depth of the indentation, surface morphology and structure of the obtained coatings, their texture and surface roughness were investigated too. The obtained results showed that the three-layer Nibright/Cubright /Niimat/CuZn37 system has highest indentation modulus and indentation hardness, following by two-layer Nibright/Cubright system and single layer coatings.

  1. The Effectiveness of Al-Si Coatings for Preventing Interfacial Reaction in Al-Mg Dissimilar Metal Welding

    Science.gov (United States)

    Wang, Yin; Al-Zubaidy, Basem; Prangnell, Philip B.

    2018-01-01

    The dissimilar welding of aluminum to magnesium is challenging because of the rapid formation of brittle intermetallic compounds (IMC) at the weld interface. An Al-Si coating interlayer was selected to address this problem, based on thermodynamic calculations which predicted that silicon would change the reaction path to avoid formation of the normally observed binary Al-Mg IMC phases ( β-Al3Mg2 and γ-Al12Mg17). Long-term static heat treatments confirmed that a Si-rich coating will preferentially produce the Mg2Si phase in competition with the less stable, β-Al3Mg2 and γ-Al12Mg17 binary IMC phases, and this reduced the overall reaction layer thickness. However, when an Al-Si clad sheet was tested in a real welding scenario, using the Refill™ friction stir spot welding (FSSW) technique, Mg2Si was only produced in very small amounts owing to the much shorter reaction time. Surprisingly, the coating still led to a significant reduction in the IMC reaction layer thickness and the welds exhibited enhanced mechanical performance, with improved strength and fracture energy. This beneficial behavior has been attributed to the softer coating material both reducing the welding temperature and giving rise to the incorporation of Si particles into the reaction layer, which toughened the brittle interfacial IMC phases during crack propagation.

  2. Coated particle waste form development

    Energy Technology Data Exchange (ETDEWEB)

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes.

  3. Coated particle waste form development

    International Nuclear Information System (INIS)

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes

  4. Characterization of Secondary Mineral Grain Coatings and their Role as Diffusion-controlled Sinks and Sources for Metal Contaminants

    Science.gov (United States)

    Davis, J. A.; Guo, H.; Lai, B.; Kemner, K. M.; Ercius, P.; Fox, P. M.; Singer, D. M.; Minor, A.; Waychunas, G.

    2012-12-01

    Many important geochemical reactions occur at the mineral-water interface, including sorption and desorption reactions of contaminants. Fundamental knowledge of the kinetics of these processes is based primarily on experimental observations of reactions at faces of single crystals or macroscopic data from pure mineral powder suspensions. Sorption reactions at crystal faces are generally very fast, on the order of microseconds or less, with reaction times often limited only by film diffusion at the mineral-water interface. In well-stirred suspensions of aquifer sediments, however, sorptive equilibrium can take many hours or days to achieve steady-state concentrations. We have examined the potential reasons for sorption rate limitation using uranium(VI) sorption by sediments from a sandy aquifer in Savannah River, South Carolina (USA). U(VI) sorption by sand-sized grains from the aquifer is dominated by reaction with secondary mineral coatings on quartz and feldspar grains. The coatings studied were on the order of 15 microns in thickness (i.e., from quartz grain to aqueous solution) and composed primarily of clay minerals and hematite of varying particle size. Microfocused-XRF imaging of elemental concentrations (e.g., U, Fe) of polished cross-sections of the grain/coating contact showed strong spatial correlations of U and Fe within the coatings, regardless of the length of reaction time (30 minutes to 4 weeks). The spatial resolution of the μ-XRF technique is of the order of 2 microns in horizontal directions, but the uncertainty of the observed spatial gradients is high due to grain curvature away from the polished surface and fluorescence contributed from the entire 30 micron thickness of a typical grain/epoxy thin section. TEM characterization of focused-ion-beam (FIB), vertically-extracted samples of the grain-coating contact shows that complex pore networks exist within the coatings of variable dimensions and unknown connectivity. Using scanning TEM (STEM

  5. Applications of nano-structured metal oxides for treatment of arsenic in water and for antimicrobial coatings

    Science.gov (United States)

    Sadu, Rakesh Babu

    Dependency of technology has been increasing radically through cellular phones for communication, data storage devices for education, drinking water purifiers for healthiness, antimicrobial-coated textiles for cleanliness, nanomedicines for deadliest diseases, solar cells for natural power, nanorobots for engineering and many more. Nanotechnology develops many unprecedented products and methodologies with its adroitness in this modern scientific world. Syntheses of nanomaterials play a significant role in the development of technology. Solution combustion and hydrothermal syntheses produce many nanomaterials with different structures and pioneering applications. Nanometal oxides, like titania, silver oxide, manganese oxide and iron oxide have their unique applications in engineering, chemistry and biochemistry. Likewise, this study talks about the syntheses and applications of nanomaterials such as magnetic graphene nanoplatelets (M-Gras) decorated with uniformly dispersed NPs, manganese doped titania nanotubes (Mn-TNTs), and silver doped titania nanopartcles (nAg-TNPs) and their polyurethane based polymer nanocomposite coating (nAg-TiO2 /PU). Basically, M-Gras, and Mn-TNTs were applied for the treatment of arsenic contaminated water, and nAg- TiO2/PU applied for antimicrobial coatings on textiles. Adsorption of arsenic over Mn- TNTs, and M-Gras was discussed while considering all the regulations of arsenic contamination in drinking water and oxidation of arsenic over Mn-TNTs also discussed with the possible surface reactions. Silver doped titania and its polyurethane nanocomposite was coated on polyester fabric and examined the coated fabric for bactericidal activity for gram-negative (E. coli) and gram-positive ( S. epidermidis) bacteria. This study elucidates the development of suitable nanomaterials and their applications to treat or rectify the environmental hazards while following the scientific standards and regulations.

  6. Adhesion profile and differentiation capacity of human adipose tissue derived mesenchymal stem cells grown on metal ion (Zn, Ag and Cu) doped hydroxyapatite nano-coated surfaces.

    Science.gov (United States)

    Bostancioglu, R Beklem; Gurbuz, Mevlut; Akyurekli, Ayse Gul; Dogan, Aydin; Koparal, A Savas; Koparal, A Tansu

    2017-07-01

    Accelerated Mesenchymal Stem Cells (MSCs) condensation and robust MSC-matrix and MSC-MSC interactions on nano-surfaces may provide critical factors contributing to such events, likely through the orchestrated signal cascades and cellular events modulated by the extracellular matrix. In this study, human adipose tissue derived mesenchymal stem cells (hMSC)', were grown on metal ion (Zn, Ag and Cu) doped hydroxyapatite (HAP) nano-coated surfaces. These metal ions are known to have different chemical and surface properties; therefore we investigated their respective contributions to cell viability, cellular behavior, osteogenic differentiation capacity and substrate-cell interaction. Nano-powders were produced using a wet chemical process. Air spray deposition was used to accumulate the metal ion doped HAP films on a glass substrate. Cell viability was determined by MTT, LDH and DNA quantitation methods Osteogenic differentiation capacity of hMSCs was analyzed with Alizarin Red Staining and Alkaline Phosphatase Specific Activity. Adhesion of the hMSCs and the effect of cell adhesion on biomaterial biocompatibility were explored through cell adhesion assay, immunofluorescence staining for vinculin and f-actin cytoskeleton components, SEM and microarray including 84 known extracellular matrix proteins and cell adhesion pathway genes, since, adhesion is the first step for good biocompability. The results demonstrate that the viability and osteogenic differentiation of the hMSCs (in growth media without osteogenic stimulation) and cell adhesion capability are higher on nanocoated surfaces that include Zn, Ag and/or Cu metal ions than commercial HAP. These results reveal that Zn, Ag and Cu metal ions contribute to the biocompatibility of exogenous material. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Salicylic acid functionalized silica-coated magnetite nanoparticles for solid phase extraction and preconcentration of some heavy metal ions from various real samples

    Directory of Open Access Journals (Sweden)

    Afkhami Abbas

    2011-07-01

    Full Text Available Abstract A method for the preconcentration of trace heavy metal ions in environmental samples has been reported. The presented method is based on the sorption of Cu(II, Cd(II, Ni(II and Cr(III ions with salicylic acid as respective chelate on silica-coated magnetite nanoparticles. Prepared adsorbent was characterized by XRD, SEM, BET and FT-IR measurements. The metals content of the sorbed complexes are eluted using 4.0 mL of 1.0 mol L-1 nitric acid. The influences of the analytical parameters including pH, amount of solid phase and condition of eluting solution, the effects of matrix ions on the retention of the analytes were examined. The accuracy and precision of suggested method were tested by analyzing of certified reference materials. The detection limits (3Sb/m, N = 8 for Cu(II, Cd(II, Ni(II and Cr(III ions are 0.22, 0.11, 0.27 and 0.15 μg L-1, respectively, and the maximum preconcentration factor is 200. The method was successfully applied to the evaluation of these trace and toxic metals in various waters, foods and other samples.

  8. Promising Ta-Ti-Zr-Si metallic glass coating without cytotoxic elements for bio-implant applications

    Science.gov (United States)

    Lai, J. J.; Lin, Y. S.; Chang, C. H.; Wei, T. Y.; Huang, J. C.; Liao, Z. X.; Lin, C. H.; Chen, C. H.

    2018-01-01

    Tantalum (Ta) is considered as one of the most promising metal due to its high corrosion resistance, excellent biocompatibility and cell adhesion/in-growth capabilities. Although there are some researches exploring the biomedical aspects of Ta and Ta based alloys, systematic characterizations of newly developed Ta-based metallic glasses in bio-implant applications is still lacking. This study employs sputtering approach to produced thin-film Ti-based metallic glasses due to the high melting temperature of Ta (3020 °C). Two fully amorphous Ta-based metallic glasses composed of Ta57Ti17Zr15Si11 and Ta75Ti10Zr8Si7 are produced and experimentally characterized in terms of their mechanical properties, bio-corrosion properties, surface hydrophilic characteristics, and in-vitro cell viability and cells attachment tests. Compare to conventional pure Ti and Ta metals, the developed Ta-based metallic glasses exhibit higher hardness and lower modulus which are better match to the mechanical properties of bone. MTS assay results show that Ta-based metallic glasses show comparable cell viability and cell attachment rate compared to that of pure Ti and Ta surface in a 72 h in-vitro test.

  9. Estimation of metal temperature of MCrAlY coated IN738 components based on interdiffusion behaviour

    DEFF Research Database (Denmark)

    Dahl, Kristian Vinter; Hald, John

    2006-01-01

    Interdiffusion at the interface between a Co-36.5Ni-17.5Cr-8Al-0.5Y, MCrAlY coating and the underlying IN738 superalloy was studied in a large matrix of specimens isothermally heat treated up to 12,000 hours at temperatures 875°C, 925°C or 950°C. Microstructural investigations and calculated phase...... fraction diagrams show that a precipitate free zone forms between the coating and superalloy and grows with time. The width of the growing zone was estimated on the basis of average intensity profiles obtained from experimental x-ray maps measured using energy dispersive spectroscopy in a scanning electron...

  10. Microstructures of Metallic NiCrBSi Coatings Manufactured via Hybrid Plasma Spray and In Situ Laser Remelting Process

    OpenAIRE

    Serres, Nicolas; Hlawka, Françoise; Costil, Sophie; Langlade, Cécile; Machi, Frédérique

    2011-01-01

    International audience; This paper deals with coating alternatives to hard chromium plating. Thermal spraying is already used in industry, but results are not always satisfactory for reasons of porosity and microstructures. In this study, atmospheric plasma spraying (APS) and in situ laser irradiation by diode laser processes were combined to modify the structural characteristics of thick NiCrBSi alloy layers. The microstructure evolution was studied, and results show that in situ laser remel...

  11. Phosphate conversion coating reduces the degradation rate and suppresses side effects of metallic magnesium implants in an animal model.

    Science.gov (United States)

    Rahim, Muhammad Imran; Tavares, Ana; Evertz, Florian; Kieke, Marc; Seitz, Jan-Marten; Eifler, Rainer; Weizbauer, Andreas; Willbold, Elmar; Jürgen Maier, Hans; Glasmacher, Birgit; Behrens, Peter; Hauser, Hansjörg; Mueller, Peter P

    2017-08-01

    Magnesium alloys have promising mechanical and biological properties for the development of degradable implants. However, rapid implant corrosion and gas accumulations in tissue impede clinical applications. With time, the implant degradation rate is reduced by a highly biocompatible, phosphate-containing corrosion layer. To circumvent initial side effects after implantation it was attempted to develop a simple in vitro procedure to generate a similarly protective phosphate corrosion layer. To this end magnesium samples were pre-incubated in phosphate solutions. The resulting coating was well adherent during routine handling procedures. It completely suppressed the initial burst of corrosion and it reduced the average in vitro magnesium degradation rate over 56 days almost two-fold. In a small animal model phosphate coatings on magnesium implants were highly biocompatible and abrogated the appearance of gas cavities in the tissue. After implantation, the phosphate coating was replaced by a layer with an elemental composition that was highly similar to the corrosion layer that had formed on plain magnesium implants. The data demonstrate that a simple pre-treatment could improve clinically relevant properties of magnesium-based implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1622-1635, 2017. © 2016 Wiley Periodicals, Inc.

  12. Effect of Bainitic Microstructure on Ballistic Performance of Armour Steel Weld Metal Using Developed High Ni-Coated Electrode

    Science.gov (United States)

    Pramanick, A. K.; Das, H.; Reddy, G. M.; Ghosh, M.; Nandy, S.; Pal, T. K.

    2018-04-01

    Welding of armour steel has gained significant importance during the past few years as recent civilian and military requirements demand weld metal properties matching with base metal having good ballistic performance along with high strength and toughness at - 40 °C as per specification. The challenge of armour steel welding therefore lies in controlling the weld metal composition which is strongly dependent on welding electrode/consumables, resulting in desired weld microstructure consisting of lower bainite along with retained austenite. The performance of butt-welded armour steel joints produced by the developed electrodes was evaluated using tensile testing, ballistic testing, impact toughness at room temperature and subzero temperature. Microstructures of weld metals are exclusively characterized by x-ray diffraction technique, scanning electron microscope and transmission electron microscopy with selected area diffraction pattern. Experimental results show that weld metal with relatively lower carbon, higher manganese and lower nickel content was attributed to lower bainite with film type of retained austenite may be considered as a most covetable microstructure for armour steel weld metal.

  13. Development and characterization of ceramic composites alumina-titania based reinforced with lanthanum oxide for fabrication of inert coatings for metallic tanks of the oil industry

    International Nuclear Information System (INIS)

    Bandeira, J.M.; Yadava, Y.P.; Silva, N.D.G.; Ferreira, R.A.S.

    2016-01-01

    Crude petroleum is highly corrosive causing superficial degradation in metallic tanks used for storage and transportation of this material, which causes a serious problem in the oil industry. An alternative to solve this problem is to use some kind of coating that is inert to this kind of corrosion. Alumina and titania are interesting materials for several engineering applications because, when compared with other ceramic materials, they present superior mechanical properties, e.g. high mechanical strength, good chemical stability and high fracture toughness combined with good wear resistance and a coefficient of thermal expansion close to the iron's, which makes them fit to use in ceramic hardening process and coating. In this paper, alumina-titania ceramic composites with 5%, 10%, 15% and 20% of titania (TiO2) and reinforced with 2% of lanthanum oxide of were produced by thermo-mechanical processing and sintering techniques at 1350 deg C. In these composites, microstructure and mechanical properties were analyzed using X-ray spectroscopy, optical microscopy, scanning electron microscopy and Vickers hardness in order to evaluate their applicability. X-ray spectroscopy showed the formation of composite without the presence of other phases. Optical microscopy and scanning electron microscopy showed a homogeneous microstructure in terms of particle size and distribution. Vickers hardness test showed a gradual decrease in hardness with the addition of titania. The composite with 5% of titania and 2% of lanthanum oxide is the best choice for structural applications. The composites were submerged in crude petroleum for 30 days to study their stability in such environment. Through the analysis of X-ray spectroscopy, optical microscopy and Vickers hardness before and after the submersion in crude petroleum, it was not observed structural or microstructural degradation nether alterations in mechanical properties. This way, it was concluded that these composites have

  14. Temperature Dependent Electrical Transport in Al/Poly(4-vinyl phenol/p-GaAs Metal-Oxide-Semiconductor by Sol-Gel Spin Coating Method

    Directory of Open Access Journals (Sweden)

    Şadan Özden

    2016-01-01

    Full Text Available Deposition of poly(4-vinyl phenol insulator layer is carried out by applying the spin coating technique onto p-type GaAs substrate so as to create Al/poly(4-vinyl phenol/p-GaAs metal-oxide-semiconductor (MOS structure. Temperature was set to 80–320 K while the current-voltage (I-V characteristics of the structure were examined in the study. Ideality factor (n and barrier height (ϕb values found in the experiment ranged from 3.13 and 0.616 eV (320 K to 11.56 and 0.147 eV (80 K. Comparing the thermionic field emission theory and thermionic emission theory, the temperature dependent ideality factor behavior displayed that thermionic field emission theory is more valid than the latter. The calculated tunneling energy was 96 meV.

  15. Fabrication of 100 A class, 1 m long coated conductor tapes by metal organic chemical vapor deposition and pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Selvamanickam, V.; Lee, H.G.; Li, Y.; Xiong, X.; Qiao, Y.; Reeves, J.; Xie, Y.; Knoll, A.; Lenseth, K

    2003-10-15

    SuperPower has been scaling up YBa{sub 2}Cu{sub 3}O{sub x}-based second-generation superconducting tapes by techniques such as pulsed laser deposition (PLD) using industrial laser and metal organic chemical vapor deposition (MOCVD). Both techniques offer advantage of high deposition rates, which is important for high throughput. Using highly-polished substrates produced in a reel-to-reel polishing facility and buffer layers deposited in a pilot ion beam assisted deposition facility, meter-long second-generation high temperature superconductor tapes have been produced. 100 A class, meter-long coated conductor tapes have been reproducibly demonstrated in this work by both MOCVD and PLD. The best results to date are 148 A over 1.06 m by MOCVD and 135 A over 1.1 m by PLD using industrial laser.

  16. Relationship between welding fume concentration and systemic inflammation after controlled exposure of human subjects with welding fumes from metal inert gas brazing of zinc-coated materials.

    Science.gov (United States)

    Brand, Peter; Bauer, Marcus; Gube, Monika; Lenz, Klaus; Reisgen, Uwe; Spiegel-Ciobanu, Vilia Elena; Kraus, Thomas

    2014-01-01

    It has been shown that exposure of subjects to emissions from a metal inert gas (MIG) brazing process of zinc-coated material led to an increase of high-sensitivity C-reactive protein (hsCRP) in the blood. In this study, the no-observed-effect level (NOEL) for such emissions was assessed. Twelve healthy subjects were exposed for 6 hours to different concentrations of MIG brazing fumes under controlled conditions. High-sensitivity C-reactive protein was measured in the blood. For welding fumes containing 1.20 and 1.50 mg m zinc, high-sensitivity C-reactive protein was increased the day after exposure. For 0.90 mg m zinc, no increase was detected. These data indicate that the no-observed-effect level for emissions from a MIG brazing process of zinc-coated material in respect to systemic inflammation is found for welding fumes with zinc concentrations between 0.90 and 1.20 mg m.

  17. Selective coupling of HE11 and TM01 modes into microfabricated fully metal-coated quartz probes

    International Nuclear Information System (INIS)

    Tortora, P.; Descrovi, E.; Aeschimann, L.; Vaccaro, L.; Herzig, H.-P.; Daendliker, R.

    2007-01-01

    We report computational and experimental investigations on injection and transmission of light in microfabricated fully Aluminum-coated quartz probes. In particular, we show that a selective coupling of either the HE 11 or the TM 01 mode can be carried out by injecting focused linearly or radially polarized beams into the probe. Optical fields, emitted by the probe after a controlled injection, are characterized in intensity and phase with the help of an interferometric technique. With the help of near-field measurement, we finally demonstrate that a longitudinally polarized spot localized at the tip apex is actually produced when the TM 01 mode is coupled into the probe

  18. Factors influencing the preparation of mullite coatings from metal chloride mixtures in CO 2 and H 2

    Science.gov (United States)

    Sotirchos, Stratis V.; Nitodas, Stephanos F.

    2002-01-01

    The preparation of mullite coatings through chemical vapor deposition (CVD) from mixtures of silicon tetrachloride, aluminum trichloride, carbon dioxide, and hydrogen is addressed in this study. The results of past experimental studies on the kinetics of this deposition system and the predictions of a mathematical model that involves detailed homogeneous and heterogeneous chemistry mechanisms for the codeposition process are used to identify operating conditions where deposition of coatings consisting of mullite or alumina-rich mullite is possible. Deposition experiments are carried out in a hot-wall reactor using as substrates both small thin plates and refractory wires traversing the centerline of the reactor. Results are presented on the dependence of the film composition in silica and alumina on temperature, pressure, and residence time of the reactive mixture in the reactor. The results showed that the alumina content of the deposits increased towards the entrance of the reactor, exceeding in many cases the value that corresponds to stoichiometric mullite. The microstructure and surface morphology of the deposit depended strongly on the operating conditions. In general, the deposition of material having the composition of mullite (2SiO 2·3Al 2O 3) or alumina-rich mullite was found to be favored by low operating pressures, high Si : Al feed ratios, and low residence times in the CVD reactor.

  19. Influence of Li and B coatings of metal walls on deuterium retention and plasma confinement in HT-7

    Science.gov (United States)

    Wang, H. Y.; Hu, J. S.; Gao, X.; Cao, B.; Li, J.; Pégourié, B.; Vacuum, HT-7; Wall Conditioning Group

    2012-10-01

    In winter 2010, the carbon plasma-facing components (PFCs) of HT-7 were changed for molybdenum PFCs. The surface area of the wall that was covered with Mo was about 1.28 m2. In the following experimental campaign, the plasma was first operated with Mo PFCs; then 28 successive lithium coatings were carried out (for a total of 350 g Li); finally, 3 g of carborane were filmed to the PFCs. In each phase, the characteristics of hydrogenic species retention were investigated as well as the energy confinement and recycling properties, offering a good opportunity for comparing similar discharges. With Mo PFCs, significant wall outgassing is generally observed and, in all cases, less than 10% of the puffed fuel is trapped, corresponding to a retention rate of around a few Pa l s-1 (1018 atom s-1) energy confinement is poor, mainly due to huge central radiation. When the PFCs are covered by lithium, about 40-80% of the puffed gas is trapped and the retention rate is 102-103 Pa l s-1 (1020-1021 atom s-1) good confinement properties are recorded, and the radiation remains located at the edge. After boronization, about 70-80% of the puffed deuterium is trapped and the retention rate is a few 102 Pa l s-1 (1020 atom s-1) the energy confinement is not as good as with Li coating, and significant radiation is measured in the plasma core.

  20. Bright metal coatings from sustainable electrolytes: the effect of molecular additives on electrodeposition of nickel from a deep eutectic solvent.

    Science.gov (United States)

    Abbott, Andrew P; Ballantyne, Andrew; Harris, Robert C; Juma, Jamil A; Ryder, Karl S

    2017-01-25

    Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the [111] orientation whereas DMH and BA direct crystal growth to the [220] orientation.

  1. Plasma spray deposition of Al-Al2O3 coatings doped with metal oxides: catalytic applications

    International Nuclear Information System (INIS)

    Pranevicius, L.; Pranevicius, L.L.; Valatkevicius, P.; Valincius, V.

    2000-01-01

    Al-Al 2 O 3 (70% γ-phase) coatings 30-50 μm thick well-adhered to the steel sheets and with a highly developed surface area (100-120 m 2 g -1 ) were formed employing plasma-spray technology at atmospheric pressure in air. The plasma-gun with two sequential powder feeders was developed offering the ability to control particle trajectories through the plasma flame, and thus their thermal history. The Al powder is mainly melted and oxidized. Al(OH) 3 powder passes through the plasma torch with partial dissociation and is incorporated in the matrix of growing film with subsequent decomposition during thermal annealing at 560 C for 90 min. The good adhesion results are explained by the surface pre-treatment effects taking place on the periphery of the plasma torch moving along the surface of steel sheets. The plasma sprayed Al-Al 2 O 3 coatings doped with CuO and Cr 2 O 3 oxides showed characteristic catalytic combustion behaviors. (orig.)

  2. Development and application of a green-chemistry solution deposition technique for buffer layer coating on cube-textured metal substrates in view of further deposition of rare-earth based superconductors

    DEFF Research Database (Denmark)

    Pallewatta, Pallewatta G A P

    which consist of YBCO superconducting coatings on cube-textured Ni based alloy tapes.  Before the epitaxial deposition this superconducting layer, a buffer layer is applied on the metal substrate as a diffusion barrier which is also required to transfer the strong texture of the underlying substrate......, allowing the epitaxial growth of the superconducting layer. State-of-the-art coated conductor hetero structures are mainly based on CeO2 based buffer stacks that consist of a sequence of several different buffer layers. Buffer layers deposited by continuous chemical deposition techniques, which...... are the most suitable for large scale production, use to suffer from porosity and cracks that lead to material diffusion from the metal substrate into the superconductor as well as oxidation of the metal during high-temperature processing of the buffer layer. SrTiO3 buffer layers have attracted interest due...

  3. Hot-Pressing Method To Prepare Imidazole-Based Zn(II) Metal-Organic Complexes Coatings for Highly Efficient Air Filtration.

    Science.gov (United States)

    Wang, Ani; Fan, Ruiqing; Zhou, Xuesong; Hao, Sue; Zheng, Xubin; Yang, Yulin

    2018-03-21

    Particulate matters (PMs) air pollution has become a serious environmental issue due to its great threat to human health. Herein, metal-organic complexes PBM-Zn1 and PBM-Zn2 coatings (noted as PBM-Zn-Filter) have been produced by the hot-pressing method on various substrates for the first time. Layer-by-layer PBM-Zn-Filters were also obtained through varying hot-pressing cycles. The obtained PBM-Zn-Filters with high robustness show excellent performance in PMs removal. In particular, benefiting from thelarger conjugation system, micropore structure, lower pressure drop, higher electrostatic potential ζ, and electron cloud exposed metal center of PBM-Zn2 (DFT calculations), PBM-Zn2@melamine foam-4 gives the highest removal rates, PM2.5:99.5% ± 1.2% and PM10:99.3% ± 1.1%, and the removal efficiency for capture PM2.5 and PM10 particles in cigarette smoke were both retained at high levels (>95.5%) after 24 h tests. More importantly, a homemade mask is made up by imbedding the PBM-Zn2@melamine foam-4 into a commercial breathing mask, which shows higher removal efficiency, lower pressure drop, smaller thickness, and higher quality factor than two commercial breathing masks, the PMs removal efficiencies for both PM2.5 and PM10 are 99.6% ± 0.5% and 99.4% ± 0.8%, and acceptable air resistance are demonstrated.

  4. Magnetic, Fluorescence and Transition Metal Ion Response Properties of 2,6-Diaminopyridine Modified Silica-Coated Fe3O4 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yunhui Zhai

    2016-08-01

    Full Text Available Multi-functional nanoparticles possessing magnetic, fluorescence and transition metal ion response properties were prepared and characterized. The particles have a core/shell structure that consists of silica-coated magnetic Fe3O4 and 2,6-diaminopyridine anchored on the silica surface via organic linker molecules. The resultant nanoparticles were found by transmission electron microscopy to be well-dispersed spherical particles with an average diameter of 10–12 nm. X-ray diffraction analysis suggested the existence of Fe3O4 and silica in/on the particle. Fourier transform infrared spectra revealed that 2,6-diaminopyridine molecules were successfully covalently bonded to the surface of magnetic composite nanoparticles. The prepared particles possessed an emission peak at 364 nm with an excitation wavelength of 307 nm and have a strong reversible response property for some transition metal ions such as Cu2+ and Zn2+. This new material holds considerable promise in selective magneto separation and optical determination applications.

  5. Metal oxide-coating PMMA or Talc as a new IR blocker inhibits IR-induced decrease of collagens in human dermal fibroblasts.

    Science.gov (United States)

    Nam, J-J; Lee, K-E; Kim, Y J

    2015-08-01

    The purpose of this study was whether P/M or T/M inhibits IR-induced decrease of collagens in human dermal fibroblasts, using P/M or T/M blocked near-IR (NIR) transmittance significantly in spectrophotometer measurement. As metal oxides are effective inorganic molecules for intercepting IR radiation, we have developed metal oxide-coating PMMA (P/M) or Talc (T/M) as a new IR blocker. Inhibitory effect of the new IR blocker on collagen degradation was measured by gene and protein expressions of procollagens and MMPs, respectively, in IR-irradiated Hs68 cell line. Using P/M or T/M inhibited IR-induced increases of MMP-1, MMP-3 and MMP-9, and IR-induced decreases of type 1 and 4 procollagen in a dose-dependent manner in dermal fibroblasts. In addition, using both P/M and T/M blocked the increase of cell media temperature induced by IR lamp. The results suggest that P/M or T/M can inhibit decrease of collagens by blocking IR-induced heat transmission in human dermal fibroblasts. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  6. Corrosion resistant coatings (Al@#2@#O@#3@#) produced by metal-organic chemical vapour deposition using ATSB

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1993-01-01

    The metal organic chemical vapour deposition (MOCVD) of amorphous alumina films on steel was performed in nitrogen at atmospheric pressure. This MOCVD process is based on the thermal decomposition of aluminium-tri-sec-butoxide (ATSB). The effect of the deposition temperature (within the range

  7. Two level undercut-profile substrate-based filamentary coated conductors produced using metal organic chemical vapor deposition

    DEFF Research Database (Denmark)

    Insinga, Andrea R.; Sundaram, Aarthi; Hazelton, Drew W.

    2018-01-01

    of a filamentary CC produced in an industrial setup by SuperPower Inc. using ion beam assisted deposition and metal organic chemical vapor deposition (IBAD-MOCVD) on a 2LUPS substrate realized at the Technical University of Denmark (DTU), whereas previous studies discussed the fabrication using alternating beam...

  8. Functional doped metal oxide films. Zinc oxide (ZnO) as transparent conducting oxide (TCO) titanium dioxide (TiO{sub 2}) as thermographic phosphor and protective coating

    Energy Technology Data Exchange (ETDEWEB)

    Nebatti Ech-Chergui, Abdelkader

    2011-07-29

    spectra indicate that the red characteristic emission of TiO{sub 2}: Eu{sup 3+} due to electric dipole {sup 5}D{sub 0} {yields}{sup 7} F{sub 2} transition occurring after ultraviolet excitation is the strongest. The decay time of the phosphorescence after UV excitation with a Nd:YAG laser (355 nm, f=10Hz) is temperature dependent in the range from 200 C up to 400 C. Finally, it has been found that the lifetime show a significant dependency on europium concentration. The development of rutile phase of titanium dioxide films on stainless steel substrates as protective coatings were investigated. Generally the rutile phases of TiO{sub 2} thin films do not adhere well on stainless steel substrates. In order to improve the adhesion, stainless steel substrates were first coated with titanium films using cathodic vacuum arc deposition. Then these titanium coatings were partially transformed to the rutile phase of titanium dioxide by thermal oxidation. The presence of the rutile phase of titanium dioxide and metallic titanium were confirmed by XRD. Cavitation erosion was used for the first time to investigate the adhesion properties of these coatings. Cavitation erosion tests confirmed that rutile films with a Ti inter layer are well adherent to stainless steel substrates and protect the substrate from erosion. The total mass loss of the thermally oxidized samples of Ti coated stainless steel was found around 3.5 times lower than of the uncoated samples. (orig.)

  9. Characterization of reflectance variability in the industrial paint application of automotive metallic coatings by using principal component analysis

    Science.gov (United States)

    Medina, José M.; Díaz, José A.

    2013-05-01

    We have applied principal component analysis to examine trial-to-trial variability of reflectances of automotive coatings that contain effect pigments. Reflectance databases were measured from different color batch productions using a multi-angle spectrophotometer. A method to classify the principal components was used based on the eigenvalue spectra. It was found that the eigenvalue spectra follow distinct power laws and depend on the detection angle. The scaling exponent provided an estimation of the correlation between reflectances and it was higher near specular reflection, suggesting a contribution from the deposition of effect pigments. Our findings indicate that principal component analysis can be a useful tool to classify different sources of spectral variability in color engineering.

  10. Growth of simplified buffer template on flexible metallic substrates for YBa2Cu3O7-δ coated conductors

    International Nuclear Information System (INIS)

    Xue, Yan; Zhang, Ya-Hui; Zhang, Fei; Zhao, Rui-Peng; Wang, Hui; Xiong, Jie; Tao, Bo-Wan

    2016-01-01

    A much simplified buffer structure, including a three-layer stack of LaMnO 3 /MgO/composite Y 2 O 3 –Al 2 O 3 , was proposed for high performance YBa 2 Cu 3 O 7-δ (YBCO) coated conductors. In this structure, biaxially textured MgO films were prepared on solution deposition planarized amorphous substrate through ion-beam-assisted deposition (IBAD) technology. By the use of in situ reflection high-energy electron diffraction monitor, X-ray diffraction and atomic force microscope, the influence of deposition parameters, such as film deposition rate, ion penetrate energy and ion beam flux, on crystalline orientation, texture, lattice parameter and surface morphology was systematically investigated. Moreover, stopping and range of ion in mater simulation was performed to study the effects of ion bombardment on MgO films. By optimizing IBAD process parameters, the best biaxial texture showed ω-scan of (002) MgO and Φ-scan of (220) MgO yield full width at half maximum values of 2.4° and 3.7°, indicating excellent biaxial texture. Subsequently, LaMnO 3 films were directly deposited on the IBAD-MgO template to improve the lattice mismatch between MgO and YBCO. Finally, YBCO films grown on this simplified buffer template exhibited a critical current density of 2.4 MA/cm 2 at 77 K and self-field, demonstrating the feasibility of this buffer structure. - Highlights: • Simplified buffer structure for YBCO coated conductors. • Growth of biaxially textured MgO films on flexible amorphous substrates. • Studying the influence of film deposition rate, ion energy and ion beam flux on the development of biaxial texture. • Demonstrating highly oriented YBCO films with a critical current density of 2.4 MA/cm 2 at self-field and 77 K.

  11. AMOchar: Amorphous manganese oxide coating of biochar improves its efficiency at removing metal(loid)s from aqueous solutions.

    Science.gov (United States)

    Trakal, Lukáš; Michálková, Zuzana; Beesley, Luke; Vítková, Martina; Ouředníček, Petr; Barceló, Andreu Piqueras; Ettler, Vojtěch; Číhalová, Sylva; Komárek, Michael

    2018-06-01

    A novel sorbent made from biochar modified with an amorphous Mn oxide (AMOchar) was compared with pure biochar, pure AMO, AMO+biochar mixtures and biochar+birnessite composite for the removal of various metal(loid)s from aqueous solutions using adsorption and solid-state analyses. In comparison with the pristine biochar, both Mn oxide-biochar composites were able to remove significantly greater quantities of various metal(loid)s from the aqueous solutions, especially at a ratio 2:1 (AMO:biochar). The AMOchar proved most efficient, removing almost 99, 91 and 51% of Pb, As and Cd, respectively. Additionally, AMOchar and AMO+biochar mixture exhibited reduced Mn leaching, compared to pure AMO. Therefore, it is concluded that the synthesis of AMO and biochar is able to produce a double acting sorbent ('dorbent') of enhanced efficiency, compared with the individual deployment of their component materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Generation of ultrahydrophobic properties of aluminium - a first step to self-cleaning transparently coated metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, M.; Worch, H.; Scharnweber, D. [Technische Univ. Dresden (Germany). Inst. fuer Werkstoffwissenschaft; Frenzel, R.; Schmidt, S.; Simon, F.; Hennig, A.; Lunkwitz, K. [Inst. fuer Polymerforschung Dresden e.V., Dresden (Germany)

    2001-09-01

    In the last few years, significant efforts have been made to provide surfaces with self-cleaning properties. This approach utilises principles which have been discovered in nature, like the well known 'Lotus-effect'. The transformation of this strategy to metallic surfaces is a scientifically and technologically challenging target. This publication focuses on the investigation of different routes for the generation of the necessary micro-morphological properties of Al. (orig.)

  13. A novel stir bar sorptive extraction coating based on monolithic material for apolar, polar organic compounds and heavy metal ions.

    Science.gov (United States)

    Huang, Xiaojia; Qiu, Ningning; Yuan, Dongxing; Huang, Benli

    2009-04-15

    In this study, a novel stir bar sorptive extraction (SBSE) based on monolithic material (SBSEM) was prepared. The monolithic material was obtained by in situ copolymerization of vinylpyrrolidone and divinylbenzene in the presence of a porogen solvent containing cyclohexanol and 1-dodecanol with azobisisobutyronitrile as initiator. The influences of polymerization conditions on the extraction efficiencies were investigated, using phenol and p-nitrophenol as detected solutes. The monolithic material was characterized by various techniques, such as elemental analysis, scanning electron microscopy, mercury intrusion porosimetry, infrared spectroscopy. Polycyclic aromatic hydrocarbons were used to investigate the extraction efficiencies of SBSEM for apolar analytes. Hormones, aromatic amines and phenols were selected as test analytes to investigate the extraction efficiencies of SBSEM for weakly and strongly polar compounds. The results showed that the new SBSEM could enrich the above-mentioned organic compounds effectively. It is worthy to mention that the SBSEM can enrich some heavy metal ions, such as Cu(2+), Pb(2+), Cr(3+) and Cd(2+), through coordination adsorption. To our best knowledge, that is the first to use SBSE to enrich heavy metal ions.

  14. RF-PACVD of water repellent and protective HMDSO coatings on bell metal surfaces: Correlation between discharge parameters and film properties

    Science.gov (United States)

    Choudhury, A. J.; Barve, S. A.; Chutia, Joyanti; Pal, A. R.; Kishore, R.; Jagannath; Pande, M.; Patil, D. S.

    2011-08-01

    Hexamethyldisiloxane (HMDSO) films have been deposited on bell metal using radiofrequency plasma assisted chemical vapor deposition (RF-PACVD) technique. The protective performances of the HMDSO films and their water repellency have been investigated as a function of DC self-bias voltage on the substrates during deposition. Plasma potential measurements during film deposition process are carried out by self-compensated emissive probe. Optical emission spectroscopy (OES) analyses of the plasma during deposition reveal no significant change in the plasma composition within the DC self-bias voltage range of -40 V to -160 V that is used. Raman and X-ray photoelectron spectroscopy (XPS) studies are carried out for film chemistry analysis and indicate that the impinging ion energy on the substrates influences the physio-chemical properties of the HMDSO films. At critical ion energy of 113 qV (corresponding to DC self-bias voltage of -100 V), the deposited HMDSO film exhibits least defective Si-O-Si chemical structure and highest inorganic character and this contributes to its best corrosion resistance behavior. The hardness and elastic modulus of the films are found to be bias dependent and are 1.27 GPa and 5.36 GPa for films deposited at -100 V. The critical load for delamination is also bias dependent and is 11 mN for this film. The water repellency of the HMDSO films is observed to be dependent on the variation in surface roughness. The results of the investigations suggest that HMDSO films deposited by RF-PACVD can be used as protective coatings on bell metal surfaces.

  15. Quantification of elemental area densities in multiple metal layers (Au/Ni/Cu) on a Cr-coated quartz glass substrate for certification of NMIJ CRM 5208-a.

    Science.gov (United States)

    Ariga, Tomoko; Zhu, Yanbei; Ito, Mika; Takatsuka, Toshiko; Terauchi, Shinya; Kurokawa, Akira; Inagaki, Kazumi

    2018-04-01

    Area densities of Au/Ni/Cu layers on a Cr-coated quartz substrate were characterized to certify a multiple-metal-layer certified reference material (NMIJ CRM5208-a) that is intended for use in the analysis of the layer area density and the thickness by an X-ray fluorescence spectrometer. The area densities of Au/Ni/Cu layers were calculated from layer mass amounts and area. The layer mass amounts were determined by using wet chemical analyses, namely inductively coupled plasma mass spectrometry (ICP-MS), isotope-dilution (ID-) ICP-MS, and inductively coupled plasma optical emission spectrometry (ICP-OES) after dissolving the layers with diluted mixture of HCl and HNO 3 (1:1, v/v). Analytical results of the layer mass amounts obtained by the methods agreed well with each another within their uncertainty ranges. The area of the layer was determined by using a high-resolution optical scanner calibrated by Japan Calibration Service System (JCSS) standard scales. The property values of area density were 1.84 ± 0.05 μg/mm 2 for Au, 8.69 ± 0.17 μg/mm 2 for Ni, and 8.80 ± 0.14 μg/mm 2 for Cu (mean ± expanded uncertainty, coverage factor k = 2). In order to assess the reliability of these values, the density of each metal layer calculated from the property values of the area density and layer thickness measured by using a scanning electron microscope were compared with available literature values and good agreement between the observed values and values obtained in previous studies.

  16. SiO2-coated magnetic graphene oxide modified with polypyrrole-polythiophene: A novel and efficient nanocomposite for solid phase extraction of trace amounts of heavy metals.

    Science.gov (United States)

    Molaei, Karam; Bagheri, Hasan; Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Shamsipur, Mojtaba

    2017-05-15

    The synthesis of a novel nanocomposite comprised of SiO 2 -coated magnetic graphene oxide modified with a pyrrole-thiophene (mGO/SiO 2 @coPPy-Th) copolymer is reported in the present work. The nanocomposite was applied for the fast magnetic solid phase extraction (MSPE) of trace levels of copper, lead, chromium, zinc and cadmium from water and agricultural samples. The nanocomposite was prepared in three steps: (1) decoration of graphene oxide sheets with magnetite nanoparticles thorough a facile one-step chemical reaction strategy; (2) chemical grafting by a silica layer to obtain high stability in acidic solutions; and (3) surface modification by coPPy-Th via simultaneous oxidation polymerization of pyrrole and thiophene in the presence of mGO/SiO 2 composite. The nanocomposite was subsequently characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Several important experimental variables that could affect MSPE performance, including the pH of the sample, sorption time, sorbent dosage, eluent type and its concentration, eluent volume and elution time, were investigated and optimized. Under optimal conditions, the limits of detection for the target heavy metals ranged from 0.15 to 0.65μgL -1 . The maximum sorption capacity of the mGO/SiO 2 @coPPy-Th nanocomposite was 201, 230, 125, 98 and 80mgg -1 for Cu(II), Pb(II), Zn(II), Cr(III) and Cd(II), respectively. Finally, the feasibility of the proposed method was investigated for the extraction and determination of the target metals from real matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. All-fiber sensor based on a metallic coated hybrid LPG-FBG structure for thermal characterization of materials

    Science.gov (United States)

    Silva, G. E.; Caldas, P.; Santos, J. C.; Santos, J. L.

    2014-05-01

    In this paper it is presented an all-fiber implementation of the hot-wire needle probe concept, widely used to measure the thermal properties of materials, particularly the thermal conductivity. It is based on the heating of a metal thin film deposited on the surface of the fiber induced by the coupling of laser light into the cladding via a long period grating, and determination, using a fiber Bragg grating, of the time dependence of the temperature of the surrounding medium at a fixed distance of the fiber. The medium considered in this research was the air and the results obtained indicate the feasibility of this approach and point out future developments.

  18. Effect of thin contaminating coating on reflectance of metallic mirror placed inside the vacuum chamber of fusion device

    International Nuclear Information System (INIS)

    Bondarenko, V.N.; Konovalov, V.G.; Bardamid, A.F.; Poperenko, L.V.; Orlinskij, D.V.

    2000-01-01

    The practice of use diagnostic mirrors inside the fusion devices revealed the appearance of a deposit on the mirror surface. Such deposit is a result of condensation of the erosion materials of those inner components that are subjected to the strongest plasma impact. Another reason for deposit growth is the wall conditioning procedures like carbonization and boronization. Appeared on the diagnostic mirrors and windows the contaminating films deteriorate the optical properties of these diagnostic elements,i.e., the mirror reflectance and window transmissivity. The object of this paper is to investigate an influence on reflectance of metal mirrors of thin films of the materials that are most probable in fusion devices under operation (boron and carbon) or can be promising in a fusion reactor (beryllium)

  19. 3,4-Dihydro-1,3-2H-benzoxazines: Novel reducing agents through one electron donation mechanism and their application as the formation of nano-metallic silver coating

    Energy Technology Data Exchange (ETDEWEB)

    Kaewvilai, Attaphon [Department of Materials Engineering, Faculty of Engineering, Kasetsart University, Chatuchak, Bangkok, 10900 (Thailand); Wattanathana, Worawat [Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900 (Thailand); Jongrungruangchok, Suchada [Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Rangsit University, Pathumthani, 12000 (Thailand); Veranitisagul, Chatchai [Department of Material and Metallurgical Engineering, Faculty of Engineering, Rajamangala University of Technology Thanyaburi, Klong 6, Thanyaburi, Pathumthani, 12110 (Thailand); Koonsaeng, Nattamon [Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900 (Thailand); Laobuthee, Apirat, E-mail: fengapl@ku.ac.th [Department of Materials Engineering, Faculty of Engineering, Kasetsart University, Chatuchak, Bangkok, 10900 (Thailand)

    2015-11-01

    3,4-dihydro-1,3-2H-benzoxazines as novel one-electron donators for silver(I) ion into nano-metallic silver was firstly found and reported. The silver formation from nano-spherical particles to coral-like and dendrite-like structures was presented. With respect to the characterization results, the feasible reaction mechanism of the silver formation was proposed as an electron donated from benzoxazine to silver(I) ion, resulting in a radical cationic species of benzoxazine and silver(0). Based on this reduction process, a new approach for nano-silver coating on various surfaces such as fumed silica (SiO{sub 2}), titanium dioxide (TiO{sub 2}), carbon black (CB), chitosan (CS) including plastic sheet (polycarbonate, PC) and pellet (polyvinyl alcohol, PVA), was also revealed. Besides the nano-silver coated products were applied as antimicrobials fillers for Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 9341, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2785 and Candida albicans ATCC 10231. - Highlights: • Benzoxazines were discovered to be novel reducing agents for silver(I) ion. • The speculated mechanism of the one electron donation process was investigated. • Dendrite structure of silver was formed from spherical silver nanoparticles. • A new approach for nano metallic-silver coating on various surfaces was revealed. • The nano-silver coated products were applied as antimicrobials fillers.

  20. 3,4-Dihydro-1,3-2H-benzoxazines: Novel reducing agents through one electron donation mechanism and their application as the formation of nano-metallic silver coating

    International Nuclear Information System (INIS)

    Kaewvilai, Attaphon; Wattanathana, Worawat; Jongrungruangchok, Suchada; Veranitisagul, Chatchai; Koonsaeng, Nattamon; Laobuthee, Apirat

    2015-01-01

    3,4-dihydro-1,3-2H-benzoxazines as novel one-electron donators for silver(I) ion into nano-metallic silver was firstly found and reported. The silver formation from nano-spherical particles to coral-like and dendrite-like structures was presented. With respect to the characterization results, the feasible reaction mechanism of the silver formation was proposed as an electron donated from benzoxazine to silver(I) ion, resulting in a radical cationic species of benzoxazine and silver(0). Based on this reduction process, a new approach for nano-silver coating on various surfaces such as fumed silica (SiO 2 ), titanium dioxide (TiO 2 ), carbon black (CB), chitosan (CS) including plastic sheet (polycarbonate, PC) and pellet (polyvinyl alcohol, PVA), was also revealed. Besides the nano-silver coated products were applied as antimicrobials fillers for Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 9341, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2785 and Candida albicans ATCC 10231. - Highlights: • Benzoxazines were discovered to be novel reducing agents for silver(I) ion. • The speculated mechanism of the one electron donation process was investigated. • Dendrite structure of silver was formed from spherical silver nanoparticles. • A new approach for nano metallic-silver coating on various surfaces was revealed. • The nano-silver coated products were applied as antimicrobials fillers.

  1. Synergistic Effects between Doped Nitrogen and Phosphorus in Metal-Free Cathode for Zinc-Air Battery from Covalent Organic Frameworks Coated CNT.

    Science.gov (United States)

    Li, Zhongtao; Zhao, Weinan; Yin, Changzhi; Wei, Liangqin; Wu, Wenting; Hu, Zhenpeng; Wu, Mingbo

    2017-12-27

    A covalent organic framework that is composed of hexachlorocyclotriphosphazene and dicyanamide has been coated on CNT to prepare metal-free oxygen reduction reaction catalyst through thermal polymerization of the Zn-air battery cathode. The N,P-codoped nanohybrids have highly porous structure and active synergistic effect between graphitic-N and -P, which promoted the electrocatalytic performance. The electrocatalysts exhibits remarkable half-wave potential (-0.162 V), high current density (6.1 mA/cm -2 ), good stability (83%), and excellent methanol tolerance for ORR in alkaline solution. Furthermore, the N,P-codoped nanohybrids were used as an air electrode for fabrication of a high performance Zn-air battery. The battery achieves a high open-circuit potential (1.53 V) and peak power density (0.255 W cm -2 ). Moreover, the effect of N,P codoping on the conjugate carbon system and the synergistic effect between graphitic-N and P have been calculated through density functional theory calculations, which are essentially in agreement with experimental data.

  2. Carbon-Coated Fe3O4/VOx Hollow Microboxes Derived from Metal-Organic Frameworks as a High-Performance Anode Material for Lithium-Ion Batteries.

    Science.gov (United States)

    Zhao, Zhi-Wei; Wen, Tao; Liang, Kuang; Jiang, Yi-Fan; Zhou, Xiao; Shen, Cong-Cong; Xu, An-Wu

    2017-02-01

    As the ever-growing demand for high-performance power sources, lithium-ion batteries with high storage capacities and outstanding rate performance have been widely considered as a promising storage device. In this work, starting with metal-organic frameworks, we have developed a facile approach to the synthesis of hybrid Fe 3 O 4 /VO x hollow microboxes via the process of hydrolysis and ion exchange and subsequent calcination. In the constructed architecture, the hollow structure provides an efficient lithium ion diffusion pathway and extra space to accommodate the volume expansion during the insertion and extraction of Li + . With the assistance of carbon coating, the obtained Fe 3 O 4 /VO x @C microboxes exhibit excellent cyclability and enhanced rate performance when employed as an anode material for lithium-ion batteries. As a result, the obtained Fe 3 O 4 /VO x @C delivers a high Coulombic efficiency (near 100%) and outstanding reversible specific capacity of 742 mAh g -1 after 400 cycles at a current density of 0.5 A g -1 . Moreover, a remarkable reversible capacity of 556 mAh g -1 could be retained even at a current density of 2 A g -1 . This study provides a fundamental understanding for the rational design of other composite oxides as high-performance electrode materials for lithium-ion batteries.

  3. Molecular Adsorber Coating

    Science.gov (United States)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  4. Electro-deposition metallic tungsten coatings in a Na{sub 2}WO{sub 4}-WO{sub 3} melt on copper based alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.H., E-mail: dreamerhong77@126.com [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Zhang, Y.C.; Liu, Q.Z.; Li, X.L.; Jiang, F. [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The tungsten coating (>1 mm) was obtained by electro-deposition method in molten salt. Black-Right-Pointing-Pointer Different thickness tungsten coatings were obtained by using different durations. Black-Right-Pointing-Pointer Good performance of coating was obtained when pulse parameters were modulated. - Abstract: The tungsten coating was prepared by electro-deposition technique on copper alloy substrate in a Na{sub 2}WO{sub 4}-WO{sub 3} melt. The coating's surface and cross-section morphologies as well as its impurities were investigated by XPS, SEM and line analysis. Various plating durations were investigated in order to obtain an optimal coating's thickness. The results demonstrated that the electro-deposited coating was compact, voidless, crackless and free from impurities. The tungsten coating's maximum Vickers hardness was measured to be 520 HV. The tungsten coating's minimum oxygen content was determined to be 0.018 wt%. Its maximum thickness was measured to be 1043.67 {mu}m when the duration of electrolysis was set to 100 h. The result of this study has demonstrated the feasibility of having thicker tungsten coatings on copper alloy substrates. These electrodeposited tungsten coatings can be potentially implemented as reliable armour for the medium heat flux plasma facing component (PFC).

  5. Constructed ILs coated porous magnetic nickel cobaltate hexagonal nanoplates sensing materials for the simultaneous detection of cumulative toxic metals

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuanyuan; Zhang, Lei, E-mail: zhanglei63@126.com

    2017-07-05

    Highlights: • A novel sensor material based on ionic liquids@nickel cobaltate was constructed. • Various morphologies of NiCo{sub 2}O{sub 4} were synthesized for electrocatalytic comparison. • ILs@NiCo{sub 2}O{sub 4}-P was used to detect cumulative toxic metals for the first time. • The sensor displayed well reproducibility, excellent selectivity and sensitivity. • The method was applied to detect practical samples with satisfactory results. - Abstract: The different morphologies of magnetic nickel cobaltate (NiCo{sub 2}O{sub 4}) electrocatalysts, consisting of nanoparticles (NiCo{sub 2}O{sub 4}-N), nanoplates (NiCo{sub 2}O{sub 4}-P) and microspheres (NiCo{sub 2}O{sub 4}-S) were fabricated. It was found that the electrocatalytic properties of the sensing materials were strongly dependent on morphology and specific surface area. The porous NiCo{sub 2}O{sub 4} hexagonal nanoplates coupled with ILs as modified materials (ILs@NiCo{sub 2}O{sub 4}-P) for the simultaneous determination of thallium (Tl{sup +}), lead (Pb{sup 2+}) and copper (Cu{sup 2+}), exhibited high sensitivity, long-time stability and good repeatability. The enhanced electrocatalytic activity was attributed to relatively large specific surface area, excellent electronic conductivity, and unique porous nanostructure. The analytical performance of the constructed electrode on detection of Tl{sup +}, Pb{sup 2+} and Cu{sup 2+} was examined using differential pulse anodic stripping voltammetry (DPASV). Under optimal conditions, the electrode showed a good linear response to Tl{sup +}, Pb{sup 2+}and Cu{sup 2+} in the concentration range of 0.1–100.0, 0.1–100.0 and 0.05–100.0 μg/L, respectively. The detection limits (S/N = 3) were 0.046, 0.034 and 0.029 μg/L for Tl{sup +}, Pb{sup 2+} and Cu{sup 2+}, respectively. The fabricated sensor was successfully applied to detect trace Tl{sup +}, Pb{sup 2+} and Cu{sup 2+} in various water and soil samples with satisfactory results. Hence, this work

  6. Metal-Organic Framework Thin Film Coated Optical Fiber Sensors: A Novel Waveguide-Based Chemical Sensing Platform.

    Science.gov (United States)

    Kim, Ki-Joong; Lu, Ping; Culp, Jeffrey T; Ohodnicki, Paul R

    2018-02-23

    Integration of optical fiber with sensitive thin films offers great potential for the realization of novel chemical sensing platforms. In this study, we present a simple design strategy and high performance of nanoporous metal-organic framework (MOF) based optical gas sensors, which enables detection of a wide range of concentrations of small molecules based upon extremely small differences in refractive indices as a function of analyte adsorption within the MOF framework. Thin and compact MOF films can be uniformly formed and tightly bound on the surface of etched optical fiber through a simple solution method which is critical for manufacturability of MOF-based sensor devices. The resulting sensors show high sensitivity/selectivity to CO 2 gas relative to other small gases (H 2 , N 2 , O 2 , and CO) with rapid (optical fiber platform which results in an amplification of inherent optical absorption present within the MOF-based sensing layer with increasing values of effective refractive index associated with adsorption of gases.

  7. Green engineering of biomolecule-coated metallic silver nanoparticles and their potential cytotoxic activity against cancer cell lines

    Science.gov (United States)

    Prasannaraj, Govindaraj; Venkatachalam, Perumal

    2017-06-01

    This report describes the synthesis of metallic silver nanoparticles (AgNPs) using extracts of four medicinal plants (Aegle marmelos (A. marmelos), Alstonia scholaris (A. scholaris), Andrographis paniculata (A. paniculata) and Centella asiatica (C. asiatica)). The bio-conjugates were characterized by UV-visible spectroscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectrometry (FTIR), x-ray diffraction (XRD) and zeta potential. This analysis confirmed that UV-Vis spectral peaks at 375 nm, 380 nm, 420 nm and 380 nm are corresponding to A. marmelos, A. scholaris, A. paniculata and C. asiatica mediated AgNPs, respectively. SEM images revealed that all the obtained four AgNPs are predominantly spherical, fibres and rectangle in shape with an average size of 36-97 nm. SEM-EDS and XRD analysis confirmed the presence of elemental AgNPs in crystalline form for all the four nanoparticle samples. The phytochemicals of various medicinal plant extracts with different functional groups were responsible for reduction of Ag+ to AgNPs, which act as capping and stabilizing agent. Among four types of AgNPs tested for anticancer activity, the Ap mediated AgNPs had shown enhanced activity against HepG2 cells (27.01 µg ml-1) and PC3 cells (32.15 µg ml-1).

  8. Microstructural and superconducting properties of high current metal-organic chemical vapor deposition YBa2Cu3O7-δ coated conductor wires

    International Nuclear Information System (INIS)

    Holesinger, T G; Maiorov, B; Ugurlu, O; Civale, L; Chen, Y; Xiong, X; Xie, Y; Selvamanickam, V

    2009-01-01

    Metal-organic chemical vapor deposition (MOCVD) on flexible, ion beam assisted deposition MgO templates has been used to produce high critical current density (J c ) (Y,Sm) 1 Ba 2 Cu 3 O y (REBCO) films suitable for use in producing practical high temperature superconducting (HTS) coated conductor wires. Thick films on tape were produced with sequential additions of 0.7 μm of REBCO via a reel-to-reel progression through a custom-designed MOCVD reactor. Multi-pass processing for thick film deposition is critically dependent upon minimizing surface secondary phase formation. Critical currents (I c s) of up to 600 A/cm width (t = 2.8 μm, J c = 2.6 MA cm -2 , 77 K, self-field) were obtained in short lengths of HTS wires. These high performance MOCVD films are characterized by closely spaced (Y,Sm) 2 O 3 nanoparticle layers that may be tilted relative to the film normal and REBCO orientation. Small shifts in the angular dependence of J c in low and intermediate applied magnetic fields can be associated with the tilted nanoparticle layers. Also present in these films were YCuO 2 nanoplates aligned with the YBCO matrix (short dimension perpendicular to the film normal), threading dislocations, and oriented composite defects (OCDs). The latter structures consist of single or multiple a-axis oriented grains coated on each side with insulating (Y,Sm) 2 O 3 or CuO. The OCDs formed a connected network of insulating phases by the end of the fourth pass. Subsequent attempts at adding additional layers did not increase I c . There is an inconsistency between the measured J c and the observed microstructural degradation that occurs with each additional layer, suggesting that previously deposited layers are improving with each repeated reactor pass. These dynamic changes suggest a role for post-processing to optimize superconducting properties of as-deposited films, addressing issues associated with reproducibility and manufacturing yield.

  9. Evolution with time of 12 metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi and U) and of lead isotopes in the snows of Coats Land (Antarctica) since the 1830's

    International Nuclear Information System (INIS)

    Planchon, F.

    2001-01-01

    This work shows that it is now possible to get reliable data on the occurrence of numerous heavy metals at ultra low levels in Antarctic snow, by combining ultra clean field sampling and laboratory sub-sampling procedures and the use of ultra sensitive analytical techniques such as ICP-SFMS and TIMS. It has allowed us to determine concentrations of twelve metals (V, Cr, Mn, Co, Cu, Zn, Ag, Cd, Ba, Pb, Bi et U) and lead isotopic composition in the ultra clean series of snow samples collected at Coats Land, in the Atlantic sector of Antarctica. This work presents a 150 years record of metal inputs from natural and anthropogenic sources to Antarctica from the 1830's to the early 1990's. Lead atmospheric pollution begins as early as the end of the 19. century, peaks during the 1970's-1980's and then falls sharply during recent decades. Evolution in lead isotopic abundance shows that Pb inputs to Antarctica reflect a complex blend of contributions originating from the Southern part of South America and Australia. For Cr, Cu, Zn, Ag, Bi and U, concentrations in the snow show significant increases from 1950 to 1980. These enhancements which cannot be explained by variations in natural inputs, illustrate that atmospheric pollution for heavy metals linked with anthropogenic activities in the Southern Hemisphere countries such as for example ferrous and non-ferrous metal mining and smelting is really global. Study of the time period 1920-1990, has allowed us to detail short-term (intra and inter annual) heavy metals concentration's changes. The large short-term variability, observed in Coats Land snow, shows the complex patterns of metal inputs to Antarctica, associated for instance to changes in long-range transport processes from mid-latitude to polar zone and to variability in the different natural sources, such local volcanic activity, sea-salt spray or crustal dust inputs. (author)

  10. Modifications of optical properties with ceramic coatings

    International Nuclear Information System (INIS)

    Besmann, T.M.; Abdel-Latif, A.I.

    1990-01-01

    Coatings of ceramic materials that exhibited high thermal absorptivities and emissivities were chemical vapor deposited on graphite and refractory metals. In this paper the coatings prepared were SiC and B 4 C, and the substrates used were graphite, molybdenum, titanium, and Nb-1Zr. The coatings are characterized with regard to adherence, optical properties, and response to potential harsh environments

  11. Electroluminescence color tuning between green and red from metal-oxide-semiconductor devices fabricated by spin-coating of rare-earth (terbium + europium) organic compounds on silicon

    Science.gov (United States)

    Matsuda, Toshihiro; Hattori, Fumihiro; Iwata, Hideyuki; Ohzone, Takashi

    2018-04-01

    Color tunable electroluminescence (EL) from metal-oxide-semiconductor devices with the rare-earth elements Tb and Eu is reported. Organic compound liquid sources of (Tb + Ba) and Eu with various Eu/Tb ratios from 0.001 to 0.4 were spin-coated on an n+-Si substrate and annealed to form an oxide insulator layer. The EL spectra had only peaks corresponding to the intrashell Tb3+/Eu3+ transitions in the spectral range from green to red, and the intensity ratio of the peaks was appropriately tuned using the appropriate Eu/Tb ratios in liquid sources. Consequently, the EL emission colors linearly changed from yellowish green to yellowish orange and eventually to reddish orange on the CIE chromaticity diagram. The gate current +I G current also affected the EL colors for the medium-Eu/Tb-ratio device. The structure of the surface insulator films analyzed by cross-sectional transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, and X-ray photoelectron spectroscopy (XPS) has four layers, namely, (Tb4O7 + Eu2O3), [Tb4O7 + Eu2O3 + (Tb/Eu/Ba)SiO x ], (Tb/Eu/Ba)SiO x , and SiO x -rich oxide. The EL mechanism proposed is that electrons injected from the Si substrate into the SiO x -rich oxide and Tb/Eu/Ba-silicate layers become hot electrons accelerated in a high electric field, and then these hot electrons excite Tb3+ and Eu3+ ions in the Tb4O7/Eu2O3 layers resulting in EL emission from Tb3+ and Eu3+ intrashell transitions.

  12. Performance of CO preferential oxidation reactor with noble-metal catalyst coated on ceramic monolith for on-board fuel processing applications

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, Rajesh K.; Zhang, Qizhi [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Chmielewski, Donald J.; Lauzze, Kevin C. [Department of Chemical and Environmental Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Inbody, Michael A. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2005-01-30

    On-board fuel processors are being developed to provide hydrogen-rich gas to the polymer electrolyte fuel cell automotive propulsion systems. Whereas the anode catalyst in the fuel cell has low tolerance for carbon monoxide, 10-100ppm, reforming of gasoline and other hydrocarbon fuels generally produces 1-2% of CO. Of the many methods of removing CO from the reformer gas, preferential oxidation (PrOx) of CO over noble-metal catalysts is practiced most frequently. In this paper, we present experimental data for CO conversion on a Pt-based catalyst that is active at room temperature and was coated on a ceramic monolith. The data is used to develop an empirical correlation for selectivity for CO oxidation as a function of CO concentration and oxygen stoichiometry at 30,000-80,000/h space velocity. The selectivity correlation is used in a model to analyze the performance of multi-stage, adiabatic PrOx reactors with heat exchange between the stages to cool the reformate to 100{sup o}C. An optimization algorithm is used to determine the operating conditions that can reduce CO concentration to 10ppm while minimizing parasitic loss of H{sub 2} in the reformate stream. It is found that the 10ppm constraint limits the maximum inlet CO concentration to 1.05% in a single-stage reactor and to 3.1% in a two-stage reactor. The results clearly show the incremental reduction in parasitic H{sub 2} loss by addition of second and third stages.

  13. Cermet coatings for solar Stirling space power

    International Nuclear Information System (INIS)

    Jaworske, Donald A.; Raack, Taylor

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic, are being considered for the heat inlet surface of a solar Stirling space power convertor. The role of the cermet coating is to absorb as much of the incident solar energy as possible. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition and the solar absorptance of these coatings. Several candidate cermet coatings were created and their solar absorptance was characterized as-manufactured and after exposure to elevated temperatures. Coating composition was purposely varied through the thickness of the coating. As a consequence of changing composition, islands of metal are thought to form in the ceramic matrix. Computer modeling indicated that diffusion of the metal atoms played an important role in island formation while the ceramic was important in locking the islands in place. Much of the solar spectrum is absorbed as it passes through this labyrinth

  14. Mitigation of chromium poisoning of cathodes in solid oxide fuel cells employing CuMn1.8O4 spinel coating on metallic interconnect

    Science.gov (United States)

    Wang, Ruofan; Sun, Zhihao; Pal, Uday B.; Gopalan, Srikanth; Basu, Soumendra N.

    2018-02-01

    Chromium poisoning is one of the major reasons for cathode performance degradation in solid oxide fuel cells (SOFCs). To mitigate the effect of Cr-poisoning, a protective coating on the surface of interconnect for suppressing Cr vaporization is necessary. Among the various coating materials, Cu-Mn spinel coating is considered to be a potential candidate due to their good thermal compatibility, high stability and good electronic conductivity at high temperature. In this study, Crofer 22 H meshes with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4 spinel coating were investigated. The lab-developed CuMn1.8O4 spinel coating were deposited on Crofer 22 H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. With these different Crofer 22 H meshes (bare, CuMn2O4-coated, and CuMn1.8O4-coated), anode-supported SOFCs with Sr-doped LaMnO3-based cathode were electrochemically tested at 800 °C for total durations of up to 288 h. Comparing the mitigating effects of the two types of Cu-Mn spinel coatings on Cr-poisoning, it was found that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in the cell electrochemical performance and significantly less Cr deposition near the cathode/electrolyte interface after the test.

  15. Foundry Coating Technology: A Review

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Tiedje, Niels Skat

    2011-01-01

    The importance of foundry coating in improving the surface quality of castings cannot be over emphasized. The appli-cation of mould and core washes creates a high thermal integrity barrier between the metal and the mould resulting in the reduction of the thermal shock experienced by the sand system....... These thermal shock leads to series of surface de-fects such as veining/finning, metal penetration, burn-on/in, scab, rat tail, erosion etc. The use of coatings reduces the tendency of occurrence of these defects. However, the understanding of the coating, its components, characteristics and mechanism of action...... is important. In this review, a detailed description of these topics and examples are provided where necessary. A potential area of research in foundry coating development, using sol-gel process is suggested. The application of sol-gel technology in the development of foundry coatings is a novel approach....

  16. Coatings for rubber bonding and paint adhesion

    Science.gov (United States)

    Boulos, M. S.; Petschel, M.

    1997-08-01

    Conversion coatings form an important base for the adhesion of paint to metal substrates and for the bonding of rubber to metal parts. Four types of conversion coatings were assessed as base treatments for the bonding of rubber to steel and for the corrosion protection of metal substrates under paint: amorphous iron phosphate, heavy zinc phosphate, and three types of modified zinc phosphates that utilized one or more metal cations in addition to zinc. When applied, these conversion coatings formed a thin film over the metal substrate that was characterized by scanning electron microscopy, x-ray diffraction, and chemical methods. The performance of the coatings was assessed using physical methods such as dry adhesion, conical mandrel, impact, and stress adhesion for the rubber-bonded parts, and by corrosion resistance methods such as humidity, salt spray, and cyclic corrosion. Coating characterization and performance were correlated.

  17. Effect of Surface Coatings on Cylinders Exposed to Underwater Shock

    Directory of Open Access Journals (Sweden)

    Y.W. Kwon

    1994-01-01

    Full Text Available The response of a coated cylinder (metallic cylinder coated with a rubber material subjected to an underwater explosion is analyzed numerically. The dynamic response of the coated cylinder appears to be adversely affected when impacted by an underwater shock wave under certain conditions of geometry and material properties of the coating. When adversely affected, significant deviations in values of axial stress, hoop stress, and strain are observed. The coated cylinder exhibits a larger deformation and higher internal energy in the metallic material. Rubber coatings appeared to inhibit energy dissipation from the metallic material to the surrounding water medium. A parametric study of various coatings was performed on both aluminum and steel cylinders. The adverse effect of the coating decreased when the stiffness of the rubber layer increased, indicating the existence of a threshold value. The results of this study indicate that the stiffness of the coating is a critical factor to the shock hardening of the coated cylinder.

  18. Chromate conversion coatings and their current application

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-04-01

    Full Text Available This paper describes formation, composition and possible production technologies of application chromate coatings. Summation of common examples of applications of these coatings in corrosion protection of metals and alloys is provided. Individual chromate coatings are divided by their dominant anions either with CrVI or CrIII. Restrictions of chromate coatings with dominantly CrVI and related toxicity of hexavalent chromium is discussed in detail. In conclusion, examples of both chromium and other, alternative coatings are summed up. Application of these coatings as a protection for concrete hot-dip galvanized reinforcement is also reviewed.

  19. Sputter coating of microspherical substrates by levitation

    Science.gov (United States)

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  20. Coating for gasifiable carbon-graphite fibers

    Science.gov (United States)

    Harper-Tervet, Jan (Inventor); Dowler, Warren L. (Inventor); Yen, Shiao-Ping S. (Inventor); Mueller, William A. (Inventor)

    1982-01-01

    A thin, uniform, firmly adherent coating of metal gasification catalyst is applied to a carbon-graphite fiber by first coating the fiber with a film-forming polymer containing functional moieties capable of reaction with the catalytic metal ions. Multivalent metal cations such as calcium cross-link the polymer such as a polyacrylic acid to insolubilize the film by forming catalytic metal macro-salt links between adjacent polymer chains. The coated fibers are used as reinforcement for resin composites and will gasify upon combustion without evolving conductive airborne fragments.

  1. REDUCTION OF S{lLPHATE CONTENT FROM COATED ALUMINA ...

    African Journals Online (AJOL)

    Coated metal catalysu find wide industrial applicatiom. The problem of these catalysts a1'e low adhesion slr'ength of the coat on the supprt, non uniform thickness of the coat and the irregular pre sy1tem. Much efforl ha.r been devoted in recent years by manufacturing new coated catalysts in order to improve· the ...

  2. High-Performance Corrosion-Resistant Materials: Iron-Based Amorphous-Metal Thermal-Spray Coatings: SAM HPCRM Program ? FY04 Annual Report ? Rev. 0 - DARPA DSO & DOE OCRWM Co-Sponsored Advanced Materials Program

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Haslam, J; Wong, F; Ji, S; Day, S; Branagan, D; Marshall, M; Meacham, B; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Buffa, E; Blue, C; Rivard, J; Beardsley, M; Weaver, D; Aprigliano, L; Kohler, L; Bayles, R; Lemieux, E; Wolejsza, T; Martin, F; Yang, N; Lucadamo, G; Perepezko, J; Hildal, K; Kaufman, L; Heuer, A; Ernst, F; Michal, G; Kahn, H; Lavernia, E

    2007-09-19

    The multi-institutional High Performance Corrosion Resistant Materials (HPCRM) Team is cosponsored by the Defense Advanced Projects Agency (DARPA) Defense Science Office (DSO) and the Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM), and has developed new corrosion-resistant, iron-based amorphous metals that can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The Fe-based corrosion-resistant, amorphous-metal coatings under development may prove of importance for applications on ships. Such coatings could be used as an 'integral drip shield' on spent fuel containers, as well as protective coatings that could be applied over welds, thereby preventing exposure to environments that might cause stress corrosion cracking. In the future, such new high-performance iron-based materials could be substituted for more-expensive nickel-based alloys, thereby enabling a reduction in the $58-billion life cycle cost for the long-term storage of the Nation's spent nuclear fuel by tens of percent.

  3. Tribology and coatings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    The future use of fuel-efficient, low-emission, advanced transportation systems (for example, those using low-heat-rejection diesel engines or advanced gas turbines) presents new challenges to tribologists and materials scientists. High service temperatures, corrosive environments, and extreme contact pressures are among the concerns that make necessary new tribological designs, novel materials, and effective lubrication concepts. Argonne is working on methods to reduce friction, wear and corrosion, such as soft metal coatings on ceramics, layered compounds, diamond coatings, and hard surfaces.

  4. Alternativa de doble recubrimiento para electrodo destinado al proceso de relleno manual con arco eléctrico//Alternative of double coating for electrode dedicated to the manual metal arc filler process

    Directory of Open Access Journals (Sweden)

    Odonel González‐Cabrera

    2014-08-01

    Full Text Available El objetivo del presente trabajo fue establecer diferencias entre el comportamiento de electrodosobtenidos con recubrimiento monocapa y bicapa para el proceso de relleno manual. La relación entrelos materiales de los recubrimientos se estableció en 70 % de materiales no metálicos y 30 % decarga de aleación para cada tipo de electrodo. Para cumplimentar el objetivo fueron evaluados los procedimientos de fabricación por inmersión y extrusión, conjuntamente con la posición relativa delos constituyentes de los recubrimientos sobre el alma y su influencia en las propiedades eléctricas y operativas de los electrodos. Como resultado se obtuvo que el electrodo con recubrimiento bicapa consume un 4,8 % menos de potencia durante la soldadura que el electrodo de recubrimiento monocapa (más económico, pero con mayor cantidad, 27 %, de metal aportado por unidad detiempo (mayor rendimiento, depositando cordones ligeramente menos altos (19,9 %, pero más profundos (46,5 %.Palabras claves: electrodos con doble recubrimiento, electrodos doblemente revestidos, relleno superficial._______________________________________________________________________________AbstractThe object of the present paper was to establish differences among one and twin coating electrodes dedicated to the manual filler process. The resulting relationship among the coating materials are established in 70 % of non-metallic compound and 30 % of alloy for each electrode type. For execute the work objective, two conventional procedures (immersion and extrusion for manufacturingelectrodes, as well as the influence of coating placement on the electrodes operational properties was evaluated. As result of experiment was obtained a twin coated electrode whish consume a 4,8 % lessthan power during the welding that one layer electrode (more economic, but with bigger quantity (27 % of metal contributed by unit of time (bigger yield, less height of reinforcement (19,9 % and greater depth of

  5. Laser-assisted coating of TI6AL4V substrate with Zinc

    CSIR Research Space (South Africa)

    Baloyi, NM

    2012-12-01

    Full Text Available Laser coating is an advanced coating technology used for improving the surface properties of metal components. The coatings produced are thick, dense, and crack-free with continuous non-porous microstructures having uniform composition which results...

  6. All-Solution-Processed, Ambient Method for ITO-Free, Roll-Coated Tandem Polymer Solar Cells using Solution- Processed Metal Films

    DEFF Research Database (Denmark)

    Angmo, Dechan; Dam, Henrik Friis; Andersen, Thomas Rieks

    2014-01-01

    A solution-processed silver film is employed in the processing of top-illuminated indium-tin-oxide (ITO)-free polymer solar cells in single- and double-junction (tandem) structures. The nontransparent silver film fully covers the substrate and serves as the bottom electrode whereas a PEDOT......:PSS/Ag grid forms the semitransparent top electrode. All layers are roll-coated/printed on a flexible substrate by using only two techniques: slot–die coating for up to 11 consecutive layers and flexo-printing for the last Ag grid layer. The slot–die coated Ag film is compared to an evaporated Ag film...... in terms of surface morphological and topographical properties and to ITO in terms of flexibility. The slot–die coated Ag film demonstrates extremely low roughness (a root-meansquare roughness of 3 nm was measured over 240_320 mm2 area), is highly conductive (

  7. Infrared stealth property based on semiconductor (M)-to-metallic (R) phase transition characteristics of W-doped VO{sub 2} thin films coated on cotton fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Zhiping, E-mail: zhpmao@dhu.edu.cn; Wang, Wei; Liu, Ying; Zhang, Linping, E-mail: zhang_lp@dhu.edu.cn; Xu, Hong; Zhong, Yi

    2014-05-02

    The infrared stealth fabric was prepared using W-doped VO{sub 2} (M) paints by the coating technology. The thermochromic W-doped VO{sub 2} (M) was synthesized through hydrolysis method and two-step calcinations under N{sub 2} atmosphere. The powders were evaluated by scanning electron microscopy, X-ray diffraction patterns and differential scanning calorimetry. The infrared emissivity of coated cotton fabric was measured by IR-2 Infrared Emissometer, which was as low as 0.752. The low infrared radiation intensity for coated cotton fabric was detected using the infrared imaging systems above the phase temperature of W-doped VO{sub 2} (M). The results indicated that the W-doped VO{sub 2} (M) thin films exhibited thermal infrared stealth performance, which could adapt to the surroundings spontaneously. - Highlights: • The infrared stealth cotton fabric was coated by W-doped VO{sub 2} as the filler. • The emissivity of coated fabric was 0.752. • The abrupt amount in the emissivity of coated fabric was 0.2 in the phase transition. • The infrared stealth cotton fabric was adaptable to the surroundings spontaneously.

  8. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  9. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  10. Scientific Fundamentals and Technological Development of Novel Biocompatible/Corrosion Resistant Ultrananocrystalline Diamond (UNCD) Coating Enabling Next Generation Superior Metal-Based Dental Implants

    Science.gov (United States)

    Kang, Karam

    Current Ti-based dental implants exhibit failure (2-10%), due to various mechanisms, including chemical corrosion of the surface of the TiO2 naturally covered Ti-based implants. This thesis focused on developing a unique biocompatible/bio-inert/corrosion resistant/low cost Ultrananocrystalline Diamond (UNCD) coating (with 3-5 nm grain size) for encapsulation of Tibased micro-implants to potentially eliminate the corrosion/mechanical induced failure of current commercial Ti-based dental implants. Microwave Plasma Chemical Vapor Deposition (MPCVD) and Hot Filament Chemical Vapor Deposition (HFCVD) processes were used to grow UNCD coatings. The surface topography and chemistry of UNCD coatings were characterized using scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopies (XPS) respectively. In conclusion, this thesis contributed to establish the optimal conditions to grow UNCD coatings on the complex 3-D geometry of Ti-based micro-implants, with geometry similar to real implants, relevant to developing UNCD-coated Ti-based dental implants with superior mechanical/chemical performance than current Ti-based implants.

  11. Steam initiated hydrotalcite conversion coatings

    DEFF Research Database (Denmark)

    Zhou, Lingli; Friis, Henrik; Roefzaad, Melanie

    2018-01-01

    A facile process of exploiting high-temperature steam to deposit nvironmentally friendly hydrotalcite (HT) coatings on Al alloy 6060 was developed in a spray system. Scanning electron microscopy showed the formationf a continuous and conformal coating comprised of a compact mass of crystallites....... A range of coating processesased on the formation of HT surface layers has been developed to examine its effect on the coating's thicknessnd corrosion resistance properties. These varieties include pre-coating cleaning (grid blasting vs. chemicaltching), metal species in HT compounds (Al-Zn HT coating vs....... Al-Li HT coating), oxidizer additives (K2S2O8,a2SO4, NH4NO3, KNO3), and post-coating treatment (Mg(CH3COO)2, Mg(CH3COO)2+Ce(NO3)3+H2O2, MgCH3COO)2+La(NO3)3). Results showed that grid blasting can increase the coating surface area, while chemical etching improves the chemical bonding connection...

  12. Silicone nanocomposite coatings for fabrics

    Science.gov (United States)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  13. Coated foams, preparation, uses and articles

    Science.gov (United States)

    Duchane, D.V.; Barthell, B.L.

    1982-10-21

    Hydrophobic cellular material is coated with a thin hydrophilic polymer skin which stretches tightly over the foam but which does not fill the cells of the foam, thus resulting in a polymer-coated foam structure having a smoothness which was not possible in the prior art. In particular, when the hydrophobic cellular material is a specially chosen hydrophobic polymer foam and is formed into arbitrarily chosen shapes prior to the coating with hydrophilic polymer, inertial confinement fusion (ICF) targets of arbitrary shapes can be produced by subsequently coating the shapes with metal or with any other suitable material. New articles of manufacture are produced, including improved ICF targets, improved integrated circuits, and improved solar reflectors and solar collectors. In the coating method, the cell size of the hydrophobic cellular material, the viscosity of the polymer solution used to coat, and the surface tension of the polymer solution used to coat are all very important to the coating.

  14. Levitation, coating, and transport of particulate materials

    International Nuclear Information System (INIS)

    Hendricks, C.D.

    1981-01-01

    Several processes in various fields require uniformly thick coatings and layers on small particles. The particles may be used as carriers of catalytic materials (platinum or other coatings), as laser fusion targets (various polymer or metallic coatings), or for biological or other tracer or interactive processes. We have devised both molecular beam and electro-dynamic techniques for levitation of the particles during coating and electrodynamic methods of controlling and transporting the particles between coating steps and to final use locations. Both molecular beam and electrodynamic techniques are described and several advantages and limitations of each will be discussed. A short movie of an operating electrodynamic levitation and transport apparatus will be shown

  15. NiTi intermetallic surface coatings by laser metal deposition for improving wear properties of Ti-6Al-4V substrates

    CSIR Research Space (South Africa)

    Mokgalaka, MN

    2014-03-01

    Full Text Available The NiTi intermetallic possesses a number of good properties, such as high wear, oxidation, and corrosion resistance. This paper focuses on the deposition of NiTi intermetallic coatings on Ti6Al4V substrate by laser melting of Ti and Ni elemental...

  16. Adhesion behaviour of CrNx coatings on pre-treated metal substrates studied in situ by PBA and ESEM after annealing

    NARCIS (Netherlands)

    Galindo, RE; van Veen, A; Schut, H; Janssen, GCAM; Hoy, R; de Hosson, JTM

    2005-01-01

    In this paper we present the first combined Positron Beam Analysis (PBA) and Environmental Scanning Electron Microscopy (ESEM) adhesion study on thin chromium nitride (CrN,) coatings. Both techniques are combined with a 4-point bending stage. PBA monitors the creation of open volume in the

  17. Plasma metallization

    International Nuclear Information System (INIS)

    Crowther, J.M.

    1997-09-01

    Many methods are currently used for the production of thin metal films. However, all of these have drawbacks associated with them, for example the need for UHV conditions, high temperatures, exotic metal precursors, or the inability to coat complex shaped objects. Reduction of supported metal salts by non-isothermal plasma treatment does not suffer from these drawbacks. In order to produce and analyse metal films before they become contaminated, a plasma chamber which could be attached directly to a UHV chamber with XPS capability was designed and built. This allowed plasma treatment of supported metal salts and surface analysis by XPS to be performed without exposure of the metal film to the atmosphere. Non-equilibrium plasma treatment of Nylon 66 supported gold(lll) chloride using hydrogen as the feed gas resulted in a 95% pure gold film, the remaining 5% of the film being carbon. If argon or helium were used as the feed gases during plasma treatment the resultant gold films were 100% pure. Some degree of surface contamination of the films due to plasma treatment was observed but was easily removed by argon ion cleaning. Hydrogen plasma reduction of glass supported silver(l) nitrate and palladium(ll) acetate films reveals that this metallization technique is applicable to a wide variety of metal salts and supports, and has also shown the ability of plasma reduction to retain the complex 'fern-like' structures seen for spin coated silver(l) nitrate layers. Some metal salts are susceptible to decomposition by X-rays. The reduction of Nylon 66 supported gold(lll) chloride films by soft X-rays to produce nanoscopic gold particles has been studied. The spontaneous reduction of these X-ray irradiated support gold(lll) chloride films on exposure to the atmosphere to produce gold rich metallic films has also been reported. (author)

  18. Method to produce catalytically active nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2017-12-19

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  19. Method to produce catalytically active nanocomposite coatings

    Science.gov (United States)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  20. Influence of the metallic matrix ratio on the wear resistance (dry and slurry abrasion) of plasma sprayed cermet (chromia / stainless steel) coatings

    Czech Academy of Sciences Publication Activity Database

    Ageorges, H.; Ctibor, Pavel; Medarhri, Z.; Touimi, S.; Fauchais, P.

    2006-01-01

    Roč. 201, č. 5 (2006), s. 2006-2011 ISSN 0257-8972 R&D Projects: GA AV ČR(CZ) 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * composite coating * tribolog y * hardness * wear * abrasion * chromia/stainless steel Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.559, year: 2006