WorldWideScience

Sample records for abrasion resistant coatings

  1. Abrasion resistance of biaxially oriented polypropylene films coated with nanocomposite hard coatings

    Science.gov (United States)

    Wang, Jing; Zhu, Yaofeng; Fu, Yaqin

    2013-11-01

    KMnO4-treated, functionalized, biaxially oriented polypropylene (BOPP) films coated with nano-silica hybrid material were synthesized. The abrasion resistance of the films was examined using a reciprocating fabric abrasion tester. Functional groups were confirmed by Fourier-transform infrared spectroscopy. Contact angle measurements were performed on the BOPP film surface to quantify the effectiveness of the functionalization. Results indicate that the abrasion resistance and roughness of the composite film were significantly affected by the modification of the BOPP film. Water surface contact angle of the modified BOPP films decreased from 90.1° to 71.4°,when KMnO4 concentration increased from 0 M to 0.25 M. Wettability of the BOPP films clearly improved after KMnO4 treatment. Abrasion resistance of the functionalized films coated with hybrid materials improved by 27.4% compared with that of the original film.

  2. Abrasive resistance of arc sprayed carbonitride alloying self-shielded coatings

    Science.gov (United States)

    Deng, Yu; Yu, Shengfu; Xing, Shule; Huang, Linbing; Lu, Yan

    2011-10-01

    Wear-resistant coatings were prepared on the surface of the Q235 low-carbon steel plate by HVAS with the carbonitride alloying self-shielded flux-cored wire. Detection and analysis on the microstructure and properties of the coatings were carried out by using scanning electron microscope, microhardness tester and wear tester. The forming, the wear resistance and its mechanism of the coatings were studied. The results show that the coatings have good forming, homogeneous microstructure and compact structure. The coatings have good hardness, the average microhardness value reaches 520 HV 0.1, and the highest value is up to about 560 HV 0.1. As a result, the coatings have good abrasive wear performance and adhesion strength.

  3. The microstructural aspects of abrasive wear resistance in composite electron beam clad coatings

    Science.gov (United States)

    Gnyusov, S. F.; Tarasov, S. Yu.

    2014-02-01

    The effect of microstructure and phase composition of composite coatings based on manganese-containing or nickel-containing austenitic steel and containing either 10 wt.% TiC or 15 wt.% WC on the abrasive wear resistance has been studied. Both post-deposition heat treatment and self-aging in the course of deposition served to improve the relative wear resistance coefficient by 38-42 and 5-12% for Fe-20%Mn-4%V-4%Mo + 15%WC and Fe-20%Ni-4%V-4%Mo + 15%WC coatings, respectively.

  4. Abrasive Wear Resistance of the Iron- and WC-based Hardfaced Coatings Evaluated with Scratch Test Method

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2013-06-01

    Full Text Available Abrasive wear is one of the most common types of wear, which makesabrasive wear resistance very important in many industries. Thehard facing is considered as useful and economical way to improve theperformance of components submitted to severe abrasive wear conditions, with wide range of applicable filler materials. The abrasive wear resistance of the three different hardfaced coatings (two iron‐based and one WC‐based, which were intended to be used for reparation of the impact plates of the ventilation mill, was investigated and compared. Abrasive wear tests were carried‐out by using the scratch tester under the dry conditions. Three normal loads of 10, 50 and 100 N and the constant sliding speed of 4 mm/s were used. Scratch test was chosen as a relatively easy and quick test method. Wear mechanism analysis showed significant influence of the hardfaced coatings structure, which, along with hardness, has determined coatings abrasive wear resistance.

  5. Structure and abrasive wear resistance of R6M5 steel-tungsten carbide composite coatings

    Science.gov (United States)

    Gnyusov, S. F.

    2012-09-01

    Features of the structure formation, composition, and abrasive wear resistance of R6M5 steel-tungsten carbide (R6M5-WC) composite coatings have been studied as dependent on the WC content. The introduction of ˜20 wt % WC into the hardening composition leads to an increase in the fraction of M6C carbide (in the form of eutectic inclusions with average size ˜5.9 μm at grain boundaries and dispersed ˜0.25 μm particles in the volume of grains), while a large proportion of metastable austenite (˜88 vol %) is still retained. The R6M5-WC coatings exhibit high abrasive wear resistance, which is ensured by the γ → α' martensite transformation during friction and a muiltimodal size distribution of hardening particles.

  6. Standard Test Method for Abrasion Resistance of Transparent Plastics and Coatings Using the Oscillating Sand Method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method determines the resistance of transparent plastics and transparent coatings utilized in windows or viewing ports, to surface abrasion using oscillating sand. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  7. Abrasion-Resistant Aluminized-Coated Aramid Fabrics for Manufacture of Firefighters’ Protective Clothing

    Science.gov (United States)

    1985-05-01

    and radiacion are also produced at the cathode surface and may profoundly influence the quality of the substrate coating. These include secondary...14,265-378 (1979). Assink, R.A. Abrasion resistant polymer reflectors for solar applications. Solar Energy Mater vol. 3:263-75, (1980). Audet, N.F. Visor... solar reflectors. Solar Energy Mater vol. 3: No.1-2,277-83,(1981). *Gubareff, G.G., J.E. Janssen, and R.H. Torborg. Thermal radiation properties survey

  8. High abrasion resistance coating materials from organic/inorganic hybrid materials produced by the sol-gel method

    OpenAIRE

    1990-01-01

    A series of new high abrasion resistance coating materials have been prepared utilizing organic/inorganic hybrid materials formed by cohydrolyzing a metal alkoxide sol (e.g. silicon, aluminum, titanium, or zirconium metal alkoxide sol) with one or more bis(trialkoxysilane-containing) organic components or related functionalized species. These hybrid materials show optical clarity and improve the abrasion resistance of polymer substrates when applied as coatings and cured on such substrates.

  9. Development and Testing of Abrasion Resistant Hard Coats For Polymer Film Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Gee, R.; DiGrazia, M.

    2010-10-01

    Reflective polymer film technology can significantly reduce the cost of solar reflectors and installed Concentrated Solar Power (CSP) plants by both reduced material cost and lower weight. One challenge of polymer reflectors in the CSP environment pertains to contact cleaning methods typically used with glass mirrors. Such contact cleaning methods can scratch the surface of polymer reflectors and thereby reduce specular reflectance. ReflecTech, Inc. (a subsidiary of SkyFuel, Inc.) and the National Renewable Energy Laboratory (NREL) initiated a cooperative research and development agreement (CRADA) to devise and develop an abrasion resistant coating (ARC) suitable for deposition onto polymer based mirror film. A number of candidate ARC products were identified as candidate formulations. Industrial collaborators prepared samples having their ARCs deposited onto ReflecTech Mirror Film pre-laminated to aluminum sheet substrates. Samples were provided for evaluation and subjected to baseline (unweathered) and accelerated exposure conditions and subsequently characterized for abrasion resistance and adhesion. An advanced ARC product has been identified that exhibits outstanding initial abrasion resistance and adhesion to ReflecTech Mirror Film. These properties were also retained after exposure to the various accelerated stress conditions. This material has been successfully manufactured as a 1.5 m wide roll-to-roll construction in a production environment.

  10. Hydrothermal treatment for TiN as abrasion resistant dental implant coating and its fibroblast response

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xingling, E-mail: shixingling1985@hotmail.com [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582 (Japan); Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huaian 223003 (China); Xu, Lingli [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Munar, Melvin L.; Ishikawa, Kunio [Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582 (Japan)

    2015-04-01

    Dental implant made of pure titanium (Ti) is prone to scratch and abrasion during routine oral hygiene procedures. This results an increase in surface roughness and therefore, facilitates the adhesion of bacteria. In severe cases, this could lead to peri-implantitis. To overcome this problem, surface modification of Ti is necessary to improve its abrasion resistance. Besides, a strong implant–gingiva interface should also be guaranteed to prevent the adhesion of bacteria. In this study, titanium nitride (TiN) coating was first prepared with gas nitriding to increase surface hardness of pure the substrate. Then, the TiN was hydrothermally treated in CaCl{sub 2} solution in order to improve its soft tissue biocompatibility. The effect of hydrothermal treatment temperature on surface properties of TiN was investigated and its biocompatibility was assessed in vitro using NIH3T3 fibroblast cell. It was determined that 120 °C was the critical temperature for the hydrothermal treatment condition. Treatment below 120 °C could incorporate Ca into TiN surface, oxidize TiN surface partially and then improve the wettability while preserving its morphology and hardness. Fibroblast cell attachment and proliferation were improved and cell spreading was enhanced on hydrothermally treated specimens compared with untreated ones. Improved wettability, Ca incorporation and negative surface due to interstitial N were believed to be the main reasons. Hydrothermal treatment is expected to make TiN a promising dental implant coating with excellent abrasion resistance and good soft tissue affinity. - Highlights: • Ca was incorporated into TiN surface while not sacrificing its hardness. • Interstitial N due to oxidation promoted Ca adsorption and cell adhesion. • Hydrothermal treatment makes TiN a promising coating for dental implant.

  11. Superhydrophilic Antireflective Periodic Mesoporous Organosilica Coating on Flexible Polyimide Substrate with Strong Abrasion-Resistance.

    Science.gov (United States)

    Wang, Jing; Zhang, Cong; Yang, Chunming; Zhang, Ce; Wang, Mengchao; Zhang, Jing; Xu, Yao

    2017-02-15

    Superhydrophilic antireflective periodic mesoporous organosilica (PMO) coating was prepared on flexible polyimide substrate via solvent-evaporation-induced self-assembly (SEISA) method, in which tetraethoxysilane (TEOS) and a special bridged silsesquioxane were used as reactants. The bridged silsesquioxane, EG-BSQ, was synthesized through the stoichiometric reaction between 3-glycidoxyporpyltrimethoxysilane (GPTMS) and ethylene diamine (EDA). Under the influence of surfactant, TEOS and EG-BSQ co-condensed and enclosed the ordered mesporous in the coating. The results of grazing-incidence small-angle X-ray scattering (GISAXS) and the transmission electron microscope (TEM) indicated that the mesopores belonged to a Fmmm orthorhombic symmetry structure. With increasing EG-BSQ concentration, the mesoporous structure in the PMO coating becomes more and more disordered because silica mesopore walls shrunk or collapsed during calcination and consequently the refractive index of PMO coating became larger. The antireflective (AR) PMO coating showed an optical transmittance of 99.54% on polyimide (PI) much higher than the 88.68% of bare PI. The water contact angle of PMO coating was less than 9.0°, which indicated the AR PMO coating was superhydrophilic. Moreover, the PMO coating showed an excellent mechanical property, the transmittance of the PMO coating displayed a very low loss of 0.1% after abrasion of 25 cycles by CS-10F wearaser.

  12. Improved Corrosion and Abrasion Resistance of Organic-Inorganic Composite Coated Electro-galvanized Steels for Digital TV Panels

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Du-Hwan; Noh, Sang-Geol; Park, Jong-Tae; Kang, Choon-Ho [POSCO Technical Research Laboratories, Pohang (Korea, Republic of)

    2015-10-15

    Recently, household electronic industries require environmentally-friendly and highly functional steels in order to enhance the quality of human life. Customers especially require both excellent corrosion and abrasion resistant anti-fingerprint steels for digital TV panels. Thus POSCO has developed new functional electro-galvanized steels, which have double coated layers with organic-inorganic composites on the zinc surface of the steel for usage as the bottom chassis panel of TVs. The inorganic solution for the bottom layer consists of inorganic phosphate, magnesium, and zirconium compounds with a small amount of epoxy binder, and affords both improved adhesion properties by chemical conversion reactions and corrosion resistance due to a self-healing effect. The composite solution for the top layer was prepared by fine dispersion of organic-inorganic ingredients that consist of a urethane modified polyacrylate polymer, hardener, silica sol and a titanium complex inhibitor in aqueous media. Both composite solutions were coated on the steel surface by using a roll coater and then cured through an induction furnace in the electro-galvanizing line. New anti-fingerprint steel was evaluated for quality performance through such procedures as the salt spray test for corrosion resistance, tribological test for abrasion resistance, and conductivity test for surface electric conductance regarding to both types of polymer resin and coating weight of composite solution. New composite coated anti-fingerprint steels afford both better corrosion resistance and abrasion properties compared to conventional anti-fingerprint steel that mainly consists of acrylate polymers. Detailed discussions of both composite solutions and experimental results suggest that urethane modifications of acrylate polymers of composite solutions play a key role in enhanced quality performances.

  13. Development of Abrasion-Resistant Coating for Solar Reflective Films. Cooperative Research and Development Final Report, CRADA Number CRD-07-247

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-01

    The purpose of this CRADA is to develop an abrasion-resistant coating, suitable for use on polymeric-based reflective films (e.g., the ReflecTech reflective film), that allows for improved scratch resistance and enables the use of aggressive cleaning techniques (e.g., direct contact methods like brushing) without damaging the specular reflectance properties of the reflective film.

  14. Final Technical Report: Development of an Abrasion-Resistant Antisoiling Coating for Front-Surface Reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Gee, Randy C. [Sundog Solar Technology, Arvada, CO (United States)

    2017-07-18

    A high-performance reflective film has been successfully developed for Concentrating Solar Power (CSP) solar concentrators. Anti-soiling properties and abrasion resistance have been incorporated into the reflector to reduce reflector cleaning costs and to enhance durability. This approach has also resulted in higher reflectance and improved specularity. From the outset of this project we focused on the use of established high-volume roll-to-roll manufacturing techniques to achieve low manufacturing costs on a per ubit area basis. Roll-to-roll manufacturng equipment has a high capital cost so there is an entire industry devoted to roll-to-roll “toll” manufacturing, where the equipment is operated “around the clock” to produce a multitude of products for a large variety of uses. Using this approach, the reflective film can be manufactured by toll coaters/converters on an as-needed basis.

  15. An abrasion-resistant and broadband antireflective silica coating by block copolymer assisted sol-gel method.

    Science.gov (United States)

    Zou, Liping; Li, Xiaoguang; Zhang, Qinghua; Shen, Jun

    2014-09-02

    A double-layer broadband antireflective (AR) coating was prepared on glass substrate via sol-gel process using two kinds of acid-catalyzed TEOS-derived silica sols. The relative dense layer with a porosity of ∼10% was obtained from an as-prepared sol, while the porous layer with a porosity of ∼55% was from a modified one with block copolymer (BCP) Pluronic F127 as template which results in abundant ordered mesopores. The two layers give rise to a reasonable refractive index gradient from air to the substrate and thus high transmittance in a wide wavelength range, and both of them have the same tough skeleton despite different porosity, for which each single-layer and the double-layer coatings all behaved well in the mechanical property tests. The high transmittance and the strong ability of resisting abrasion make this coating promising for applications in some harsh conditions. In addition, the preparation is simple, low-cost, time-saving, and flexible for realizing the optical property.

  16. Abrasive wear resistance optimization of three different carbide coatings by the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Guer, Ali Kaya [Firat Univ., Elazig (Turkey). Dept. of Metallurgy and Materials; Kaya, Sinan [Firat Univ., Elazig (Turkey). Faculty of Technology

    2017-06-01

    In this study, FeCrC, SiC and B{sub 4}C powders were alloyed on the surface of AISI 430 ferritic stainless steel by plasma arc welding. The mass losses of the abrasive wear of the AISI 430 substrate were examined under the loads of 6, 10 and 16 N and in the distances of 10, 20 and 30 m by using Taguchi design method. The results of abrasive wear test were optimized by the minimum optimal control characteristics of the Taguchi procedure and the results were analyzed by using graphical methods. The Taguchi procedure is an important approach to achieve high quality without increasing the cost during the optimization of process parameters. The orthogonal planes of maximum effects of the controllable process parameters and minimum effects of uncontrollable process parameters were employed in the Taguchi method.

  17. Abrasive Wear Study of NiCrFeSiB Flame Sprayed Coating

    Science.gov (United States)

    Sharma, Satpal

    2013-10-01

    In the present study, abrasive wear behavior of NiCrFeSiB alloy coating on carbon steel was investigated. The NiCrFeSiB coating powder was deposited by flame spraying process. The microstructure, porosity and hardness of the coatings were evaluated. Elemental mapping was carried out in order to study the distribution of various elements in the coating. The abrasive wear behavior of these coatings was investigated under three normal loads (5, 10 and 15 N) and two abrasive grit sizes (120 and 320 grit). The abrasive wear rate was found to increase with the increase of load and abrasive size. The abrasive wear resistance of coating was found to be 2-3 times as compared to the substrate. Analysis of the scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this investigation.

  18. Abrasion resistant low friction and ultra-hard magnetron sputtered AlMgB14 coatings

    Science.gov (United States)

    Grishin, A. M.

    2016-04-01

    Hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric AlMgB14 ceramic target. X-ray amorphous AlMgB14 films are very smooth. Their roughness does not exceed the roughness of Si wafer and Corning glass used as the substrates. Dispersion of refractive index and extinction coefficient were determined within 300 to 2500 nm range for the film deposited onto Corning glass. Stoichiometric in-depth compositionally homogeneous 2 μm thick films on the Si(100) wafer possess the peak values of nanohardness 88 GPa and Young’s modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 GPa and 275 GPa at 200 nm depth. Friction coefficient was found to be 0.06. The coating scratch adhesion strength of 14 N was obtained as the first chipping of the coating whereas its spallation failure happened at 21 N. These critical loads and the work of adhesion, estimated as high as 18.4 J m-2, surpass characteristics of diamond like carbon films deposited onto tungsten carbide-cobalt (WC-Co) substrates.

  19. Microstructure and Abrasion Resistance of In-situ TiC Particles Reinforced Ni-based Composite Coatings by Laser Cladding

    Directory of Open Access Journals (Sweden)

    MA Shi-bang

    2017-06-01

    Full Text Available Laser cladding of Ni-based Ni60A+x% (SiC+Ti(mass fraction,the same below composite powder coating on 45 steel substrate was studied by using the method of preplaced powder. The dry friction and wear experiments of different material coatings were carried out by reciprocating friction wear tester. The microstructure and worn morphology of cladding layers were observed and analyzed by using metallographic microscope, scanning electron microscope(SEM respectively. The results show that the prepared composite coating with dispersively distributed TiC enhanced particles are obtained in-situ, the size and number of the granular TiC gradually increase with the increase of the composite powder SiC+Ti. When the composite powder SiC+Ti reaches 60%, pores and inclusions defects exist in microstructure. When the composite powder SiC+Ti reaches 48%, wear resistance of cladding coating is the best. The wear behavior of the composite coating is abrasive wear, and the mechanism is micro cutting and extrusion spalling.

  20. HVOF- and HVAF-Sprayed Cr3C2-NiCr Coatings Deposited from Feedstock Powders of Spherical Morphology: Microstructure Formation and High-Stress Abrasive Wear Resistance Up to 800 °C

    Science.gov (United States)

    Janka, L.; Norpoth, J.; Trache, R.; Thiele, S.; Berger, L.-M.

    2017-08-01

    Chromium carbide-based coatings are commonly applied to protect surfaces against wear at high temperatures. This work discusses the influence of feedstock powder and spray torch selection on the microstructure and high-stress abrasion resistance of thermally sprayed Cr3C2-NiCr coatings. Four commercial feedstock powders with spherical morphology and different microstructures were deposited by different high-velocity spray processes, namely third-generation gas- and liquid-fueled HVOF torches and by the latest generation HVAF torch. The microstructures of the coatings were studied in the as-sprayed state and after various heat treatments. The high-stress abrasion resistance of as-sprayed and heat-treated coatings was tested at room temperature and at 800 °C. The study reveals that the selection of the spray torch mainly affects the room temperature abrasion resistance of the as-sprayed coatings, which is due to differences in the embrittlement of the binder phase generated by carbide dissolution. At elevated temperatures, precipitation and growth of secondary carbides yields a fast equalization of the various coatings microstructures and wear properties.

  1. Research on the abrasive wear resistance of YDCrMoV coating produced by CO2 shielded flux-cored wire surfacing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Caterpillar construction machines play an important part in many fields such as hydraulic and electric engineering, the construction of highway, for its particular of structure. The walking system of caterpillar construction machines is always under the condition of three-body abrasive wear. The abrasive wear of walking system is very severe, which always results in damages of components or structures of walking system of caterpillar construction machines. It is very important to repair the walking system by cladding technique. The abrasive wear properties of four kinds coatings produced by the shielded flux-cored wire surfacing for the repair of the damaged components of walking system of caterpillar construction machines have been studied experimentally on an MLS-23 type wet sand rubber wheel abrasive tester. The surfaces morphologies of the abrasively worn specimens and their microstructures are investigated by transmitting electron microscopy (TEM) after wear testing. Results show that the wear mechanism of cladding metals of the flux-cored wire No.1 and the No.2 is micro-cutting while that of the No.3 and the No.4 is micro-ploughing. The four kinds of flux-cored wire coatings present great potential applications for the repairing of caterpillar construction machines in the Three Gorges Engineering.

  2. Abrasive wear characteristics and mechanisms of Al2O3/PA1010 composite coatings

    Institute of Scientific and Technical Information of China (English)

    JIA Xian; LING Xiaomei

    2004-01-01

    The abrasive wear characteristics of Al2O3/PA1010 composite coatings on the surface of quenched and low-temperature temper steel 45 were tested on the mmplate abrasive wear testing machine and the same uncoated steel 45 was used as a reference material. Experimental results showed that the abrasive wear resistance of Al2O3//PAl010 composite coatings has a good linear relationship with the volume fraction of Al2O3 particles in Al2O3/PAl010 composite coatings, and the linear correlative coefficient is 0.979. Under the experimental conditions, the size of Al2O3 particles (40.5-161.0 μm) has little influence on the abrasive wear resistance of Al2O3/PA l010 composite coatings. By treating the surface of Al2O3 particles with a suitable bonding agent, the distribution of Al2O3 particles in matrix PAl010 is more homogeneous and the bonding state between Al2O3 particles and matrix PAl010 is better. Therefore, the ml2O3 particles in Al2O3/PA1010 composite coatings make the Al2O3/PAl010 composite coatings have better abrasive wear resistance than PA1010 coatings. The wear resistance of Al2O3/PA 1010 composite coatings is about 45% compared with that of steel 45.

  3. Performance of Flame Sprayed Ni-WC Coating under Abrasive Wear Conditions

    Science.gov (United States)

    Harsha, S.; Dwivedi, D. K.; Agarwal, A.

    2008-02-01

    This paper describes the influence of a post spray heat treatment on the microstructure, microhardness and abrasive wear behavior of the flame sprayed Ni-WC (EWAC 1002 ET) coating deposited on the mild steel. Coatings were deposited by using an oxy-acetylene flame spraying torch (Superjet Eutalloy L & T, India). The wear behavior of the coating was evaluated using a pin on disc wear system against SiC abrasive medium of 120 and 600 grades at 5, 10, 15, and 20 N normal load. Results revealed that the influence of normal load on wear is governed by the microstructure, hardness and abrasive grit size. The heat treatment increased average microhardness of the coating. However, it was found that the hardness does not correctly indicate the abrasive wear resistance of Ni-WC coating in an as sprayed and heat treated condition. The heat treatment of the coating improved its abrasive wear resistance against fine abrasive medium while the wear resistance against coarse abrasive was found to be a function of a normal load. At low-normal load (5 and 10 N) the heat treated coating showed lower-wear rate than as spayed coating while at high-normal loads (15 and 20 N) heat treated coating was subjected to higher-wear rate than as sprayed coating. In general, an increase in normal load increased the wear rate. The scanning electron microscopy study indicated that the wear largely takes place by groove formation and scoring of eutectic matrix and the fragmentation of the carbide particles.

  4. 低压等离子喷涂MoB/CoCr涂层的组织及耐磨性%Microstructure and Abrasive Wear Resistance of MoB/CoCr Coatings by LPPS

    Institute of Scientific and Technical Information of China (English)

    陈枭; 纪岗昌; 王洪涛

    2012-01-01

    MoB/CoCr coatings were prepared by low pressure plasma spraying(I.PPS), the abrasive wear experiment was investigated. The surface and cross sectional morphologies of the MoB/CoCr coatings were observed by SEM. The properties of microhardness And bond strength of the MoB/CoCr coatings were iested. The abrasive wear properties were evaluated by MLS-225 wet sand rubber wheel tester. The results show that MoB/CoCr coatings are dense and have excellent mechanical properties with high microhardness(930HV0. 3) and bond strength(71 Mpa). The MoB/CoCr coatings have high abrasive wear resistance property.%采用低压等离子喷涂技术(LPPS)制备MoB/CoCr潦层,对涂层进行磨粒磨损试验研究.采用SEM观察涂层的表面和截面形貌,显微硬度计测试潦层的力学性能,湿式橡胶轮磨粒磨损试验机测试潦层的磨粒磨损性能.结果表明,涂层组织致密,呈层状结构;涂层具有良好的力学性能,显微硬度达到930HV0.3,结合强度在71MPa以上,具有较高的耐磨性能.

  5. Micro-scale abrasion behaviour of electroless Ni-P-SiC coating on aluminium alloy

    OpenAIRE

    2014-01-01

    Electroless nickel (EN) and electroless nickel composite (ENC) coatings were deposited on aluminium alloy substrate, LM24. The micro abrasion test was conducted to study the wear behaviour of the coatings with the effect of SiC concentration. Microhardness of the coatings was tested also. The wear scars were analysed using optical microscope and scanning electron microscope (SEM). The wear resistance was found to be improved in composite coating that has higher microhardness as compared to pa...

  6. Research on Abrasive Wear Resistance of Ni-Ti Coating Prepared by High Velocity Air-fuel Arc Spraying%超音速电弧喷涂Ni-Ti涂层的磨粒磨损性能研究

    Institute of Scientific and Technical Information of China (English)

    张健; 周勇; 张志萍

    2012-01-01

    采用超音速电弧喷涂工艺在2Cr13马氏体不锈钢基体上制备了Ni-Ti涂层.用X射线衍射研究了涂层的相组成,用扫描电镜对涂层的显微结构和磨损后形貌进行了分析,测试了涂层的显微硬度,在橡胶轮磨粒磨损试验机上研究了涂层的耐磨粒磨损性能.结果表明,Ni-Ti涂层主要组织为NiTi(B2)相和一定量的TiO、NiO等氧化物,该涂层不仅有较高的硬度,而且较2Cr13基体有更加良好的耐磨粒磨损性能.%Ni-Ti coating was prepared on 2Crl3 martensitic stainless steel substrate by high velocity air-fuel arc spraying. The phase composition of the coating was investigated by XRD; the microstructure and the worn surface morphology of the coating were analyzed by SEM; the microhardness of the coating was determined; the abrasive resistance of the coating was studied by rubber wheel abrasion tester. The results show that Ni-Ti coating is mainly composed of NiTi (B2) phase and some oxides such as TiO and NiO. The coating is of higher hardness and has much better abrasive wear resistance than 2Crl3 substrate.

  7. The Anti-cavitation and Abrasion Resistant Spray Coating Application of Sea Water Pump Impellers in the Nuclear Power%抗磨蚀金属涂层在核电海水泵叶轮的应用

    Institute of Scientific and Technical Information of China (English)

    黄科峰; 许彪; 吴树辉; 叶林; 尹嵩; 史一岭

    2012-01-01

    本文选取WC10Co4Cr喷涂材料,采用HVOF方法工艺在基材45#钢上制备涂层,与基材在自制圆盘式磨蚀试验台上进行磨蚀破坏试验,并将基材与涂层材料的抗磨蚀性能进行比较分析,最终将金属涂层应用于核电海水循环泵的叶轮抗磨蚀改造中,取得良好效果。%In this study, WC10Co4Cr coatings on the No.45 steel substrate surface have been formed by High Velocity Oxy Fuel (HVOF) spraying. The cavitation and abrasion behavior of coatings and the substrate has been investigated using a self-manufactured rotating disk system. Anti-cavitation and abrasion resistance properties have been illustrated and analyzed with the substrate by the cumulative mass loss curves. WC 10Co4Cr coatings have been used to build up the anti-cavitation and abrasion resistance properties of the main circulating water pump impeller in the nuclear power, and gets good effect.

  8. Recent progress of abrasion-resistant materials: learning from nature.

    Science.gov (United States)

    Meng, Jingxin; Zhang, Pengchao; Wang, Shutao

    2016-01-21

    Abrasion-resistant materials have attracted great attention for their broad applications in industry, biomedicine and military. However, the development of abrasion-resistant materials that have with unique features such as being lightweight and flexible remains a great challenge in order to satisfy unmet demands. The outstanding performance of natural abrasion-resistant materials motivates the development of new bio-inspired abrasion-resistant materials. This review summarizes the recent progress in the investigation of natural abrasion-resistant materials to explore their general design principles (i.e., the correlation between chemical components and structural features). Following natural design principles, several artificial abrasion-resistant materials have shown unique abrasion-resistant properties. The potential challenges in the future and possible solutions for designing bio-inspired abrasion-resistant materials are also briefly discussed.

  9. Micro-scale Abrasion and Medium Load Multiple Scratch Tests of PVD Coatings.

    Institute of Scientific and Technical Information of China (English)

    S.Poulat; H.Sun; D.GTeer

    2004-01-01

    Micro-scale abrasion testing is widely used to determine the abrasion resistance of thin film coatings; it is a simple technique that can easily be used as part of a quality control procedure, but it has got the disadvantage of not allowing an easy study of the wear mechanisms involved: it is difficult to estimate the load applied on each abrasive particles in the contact between the loaded ball and the specimen. The possibility of using progressive loading scratch testing, a method widely used to assess the adhesion of thin film coatings, to model the abrasive wear of coatings has been studied in the past; the use of multiple scratch tests to study the wear mechanisms corresponding to a single abrasion scratch event has also been studied in the case of bulk materials (ceramics and hard metals). Two coatings, deposited by Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUBMSIP) on ASP23 powder metallurgy steel substrate are chosen to be representative of the use of protective coatings in industry: titanium nitride, which is widely used to prevent tool wear, and TCL Graphit-iCTM, which is widely used as a wear resistant solid lubricant coating. The two coatings are first characterised by using a standard quality control procedure: their thickness is determined by the cap grinding method, their adhesion by progressive loading scratch. Then micro-scale abrasion tests performed with a slurry at a concentration which promotes grooving wear, and medium load multiple scratch tests performed with diamond indenters are completed; the results of these tests are analysed and compared to determine if there is any correlation between the two sets of results; the multiple scratch tests wear tracks are also observed to determine the wear mechanisms involved.

  10. Usage of abrasion-resistant materials in agriculture

    Directory of Open Access Journals (Sweden)

    J Votava

    2014-06-01

    Full Text Available Agricultural soil-processing machines are subject to an extensive abrasive wear. This paper analyses technical materials and their fitness to exchangeable parts of plough bottoms, such as edge-tools and whole plough cutting edges. There were tested abrasion-resistant steels with different microstructures: austenite, martensite-bainite, and carbide. Steel with the pearlite-ferrite structure was used as an etalon. Abrasion resistance tests were processed in compliance with the norm CSN 01 5084, which is a test of abrasion wear on abrasive cloth.

  11. Abrasion Resistance Comparison between Rotor and Ring Spun Yarn

    Institute of Scientific and Technical Information of China (English)

    YANG Jian-ping; YU Chong-wen

    2002-01-01

    On the base of literature review and the analysis of yarn properties, yarn structure and some other facts, the abrasion resistance of both rotor spun yarn and ring spun yarns are discussed. The results show that with the same raw material and twist, the rotor spun yarn has lower abrasion resistance than that of ring spun yarn, because of the higher twist employed, the abrasion resistance of rotor spun yarn is higher than that of ring spun yarn.

  12. The Abrasion-resistance Investigation of Rubberized Concrete

    Institute of Scientific and Technical Information of China (English)

    KANG Jingfu; ZHANG Bo; LI Guangyu

    2012-01-01

    The abrasion resistance properties of rubberized concrete were comparatively studied by taking silica fume and crumb tire rubber as the additives.The abrasion tests were conducted in accordance with the Chinese standard test method DL/T 5150-2001,two recommended test methods:under water method and ring method,were used.The crumb tire rubbers with the sieve size of 8-mesh and 16-mesh were incorporated into the concrete by replacing same volume of sand and as an additive.The abrasion resistance of concrete was evaluated according to the abrasion resistance strength and the mass loss.Test results show that the addition of silica fume enhanced both compressive strength and abrasion resistance of concrete,and the addition of crumb rubber reduced the compressive strength but increased notably the abrasion resistance of the concrete.Silica fume concrete performed a better abrasion resistance than control concrete,and the rubberized concrete performed a much better abrasion resistance than silica fume concrete.The abrasion resistance of rubberized concrete increased with the increase of rubber content.

  13. Abrasion Resistant Refractory Materials GB/T 23294-2009

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyuan

    2009-01-01

    @@ 1 Scope This standard specifies the definition, classification, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage, and quality certificate of abrasion resistant refractory materials. This standard is applicable to abrasion resistant refractory materials for circulating fluidized bed boilers, daily waste incinerator, industrial waste incinerator, medical waste incinerator, ordinary solid waste incinerator, hazardous waste incinerator, etc.

  14. RESISTANCE OF COATED ELECTRODES SUITABLE FOR RENOVATION OF TILLAGE TOOLS

    OpenAIRE

    2013-01-01

    This article deals with the abrasive wear resistance of additional materials. The resistance of individual materials was figured out by determining a proportional wear resistance on a grinding fabric. Results of the experiment confirmed an increase in welds abrasive wear resistance. Chosen coated electrodes are suitable for the renovation of tillage tools of agricultural machines.

  15. Electrical resistivity measurements to predict abrasion resistance of rock aggregates

    Indian Academy of Sciences (India)

    Sair Kahraman; Mustafa Fener

    2008-04-01

    The prediction of Los Angeles (LA) abrasion loss from some indirect tests is useful for practical applications. For this purpose, LA abrasion, electrical resistivity, density and porosity tests were carried out on 27 different rock types. LA abrasion loss values were correlated with electrical resistivity and a good correlation between the two parameters was found. To see the effect of rock class on the correlation, regression analysis was repeated for igneous rocks, metamorphic rocks and sedimentary rocks, respectively. It was seen that correlation coefficients were increased for the rock classes. In addition, the data were divided into two groups according to porosity and density, respectively. After repeating regression analysis for these porosity and density groups, stronger correlations were obtained compared to the equation derived for all rocks. The validity of the derived equations was statistically tested and it was shown that all derived equations were significant. Finally, it can be said that all derived equations can alternatively be used for the estimation of LA abrasion loss from electrical resistivity.

  16. Structure and Abrasive Wear of Composite HSS M2/WC Coating

    Directory of Open Access Journals (Sweden)

    S. F. Gnyusov

    2012-01-01

    Full Text Available Features of phase-structure formation and abrasive wear resistance of composite coatings “WC-M2 steel” worn against tungsten monocarbide have been investigated. It was established that adding 20 wt.% WC to the deposited powder mixture leads to the increase in M6C carbide content. These carbides show a multimodal size distribution consisting of ~5.9 μm eutectic carbides along the grain boundaries, ~0.25 μm carbides dispersed inside the grains. Also a greater amount of metastable austenite (~88 vol.% is found. The high abrasive wear resistance of these coatings is provided by γ→α′-martensitic transformation and multimodal size distribution of reinforcing particles.

  17. Abrasive Wear Behavior of WC Reinforced Ni-BASED Composite Coating Sprayed and Fused by Oxy-Acetylene Flame

    Science.gov (United States)

    Wang, Qun; Chen, Zhenhua; Ding, Zhang Xiong; Chen, Ding

    Microstructure of WC reinforced Ni-based self-fluxing alloy composite coating sprayed and fused by oxy-acetylene flame was investigated by scanning electron microscopy and energy dispersive X-ray Spectrometry, X-ray diffraction, and transmission electron microscopy. The wear performance of the coating was studied by a MLS-225 wet sand rubber wheel abrasive wear tester at various loads and sizes of abrasive particles. Also, the wear resistance of the coating was compared with uncoated ASTM1020 steel. The results indicated that the coating is bonded metallurgically to the substrate and has a homogeneous microstructure composed of both coarse WC and fine carbide and boride grains such as Cr7C3, Cr23C6, and Ni2B which disperse uniformly in the matrix of γ-Ni solid solution and Ni3B. The worn mass loss of the coating and ASTM1020 steel both increased with the load and size of abrasive particles, also, the coating has exhibited excellent abrasive wear resistance compared with ASTM1020 steel.

  18. Abrasion, Erosion and Cavitation Erosion Wear Properties of Thermally Sprayed Alumina Based Coatings

    Directory of Open Access Journals (Sweden)

    Ville Matikainen

    2014-01-01

    Full Text Available Thermally-sprayed alumina based materials, e.g., alumina-titania (Al2O3-TiO2, are commonly applied as wear resistant coatings in industrial applications. Properties of the coatings depend on the spray process, powder morphology, and chemical composition of the powder. In this study, wear resistant coatings from Al2O3 and Al2O3-13TiO2 powders were sprayed with plasma and high-velocity oxygen-fuel (HVOF spray processes. Both, fused and crushed, and agglomerated and sintered Al2O3-13TiO2 powders were studied and compared to pure Al2O3. The coatings were tested for abrasion, erosion, and cavitation resistances in order to study the effect of the coating structure on the wear behavior. Improved coating properties were achieved when agglomerated and sintered nanostructured Al2O3-13TiO2 powder was used in plasma spraying. Coatings with the highest wear resistance in all tests were produced by HVOF spraying from fused and crushed powders.

  19. Preparation and Abrasion Performance Study of High-Temperature and Wear-Resisting Metal Substrate Compound Coatings%金属基体高温耐磨复合涂层的制备与磨损性能研究

    Institute of Scientific and Technical Information of China (English)

    程银健; 陈九磅; 王平; 桂老虎

    2011-01-01

    The heating surface wear of boiler metal wall is a difficult problem troubling power plant safe operation. By using modified inorganic silicon sol as bond, wearability excellent SiC, Al2O3 particles as the basic aggregate assisted by a few Cr2 O3 grain, adding a small amount of bentonite and inorganic fibers for reinforced materials, the adhesion between coatings and substrate are improved. The experimental coatings were obtained after curing at 500 ℃. In regerd to blunt angle of 15°, 25°, 45°, 35°, 60°, respectively, the corrosion-proof and wear resislance of the coatings are studied. Experiments have found: the abrasion resistance of SiC - Al2 O3 composite coatings with different particle sizes behave wear-resistance better than that with singre particle size. When the mass fraction of coarse SiC is 45%, the wear resistance is the bests In the erosion angle 45°, the coatings wear are the most.%锅炉受热面金属管壁的磨损问题是困扰电厂安全运行的一大难题.实验采用改性无机粘结剂,以耐磨性优良的SiC、Al2O3颗粒为基本骨料,辅以少量Cr2O3颗粒,再添加少量的膨润土和无机纤维为增强材料,提高涂层和基体间的结合力.在500℃下固化后得到实验涂层.分别在冲蚀角15°、25°、35°、45°、60°下研究了涂层耐冲蚀磨损特性.实验发现:不同粒径的SiC-Al2O3复合涂层结合紧密,比单一组分涂层耐磨性好.当粗SiC的质量分数为45%时,涂层耐磨损性能最好;在冲蚀角为45°时,涂层的磨损量最大.

  20. Effect of binder on abrasive wear resistance of tungsten carbide coating prepared by HVOF spraying%粘结剂对超音速火焰喷涂碳化钨涂层磨粒磨损性能的影响

    Institute of Scientific and Technical Information of China (English)

    梁文军; 张宏; 沈承金; 马瑞勇

    2012-01-01

    WC-lONi and WC-12Co coatings were deposited on 35 steel substrate by HVOF (high velocity oxygen fuel) spraying process. The effects of Ni and Co as binders on microhardness, friction coefficient, and abrasive wear resistance of WC coating were studied. The surface morphologies of the coating before and after wearing were analyzed by scanning electron microscopy (SEM) and the mechanism of abrasive wear was discussed. The results indicated that both WC coatings prepared by HVOF have high microhardness, and show little difference in friction coefficient when they rub against SiC sandpaper under dry friction condition. Both coatings have good anti-abrasive wear performance at low load, while at high load the WC-12Co coating has obviously better wear resistance than the WC-lONi coating. Their main abrasive wear form is uniform abrasion wear and the abrasive wear mechanismis mainly micro-cutting and micro-peeling. The surface damage of the WC-12Co coating after wearing is lighter and has better comprehensive performance as compared with the WC-lONi coating.%采用超音速火焰喷涂(HVOF)工艺在35钢基体上制备了WC- 10Ni涂层和WC- 12Co涂层,研究了镍、钴这两种粘结剂对WC涂层的显微硬度、摩擦系数和抗磨粒磨损性能的影响,采用扫描电子显微镜观察涂层磨损前后的表面形貌,探讨了WC涂层的磨粒磨损机理.结果表明,以HVOF方法制备的2种WC涂层均有较高的显微硬度,WC- 10Ni涂层和WC- 12Co涂层与SiC砂纸摩擦副之间的干摩擦系数相差不大.2种涂层在低载荷下均有较好的抗磨粒磨损性能,但在较高载荷下WC- 12Co涂层的抗磨性明显优于WC-10Ni涂层.2种涂层的磨粒磨损形式主要为均匀磨耗磨损,磨损机理以微切削和微剥落为主.WC-12Co涂层的磨损表面损伤较轻微,综合性能优于WC- 10Ni涂层.

  1. Hybrid inorganic-organic materials: Novel poly(propylene oxide)-based ceramers, abrasion-resistant sol-gel coatings for metals, and epoxy-clay nanocomposites, with an additional chapter on: Metallocene-catalyzed linear polyethylene

    Science.gov (United States)

    Jordens, Kurt

    1999-12-01

    The sol-gel process has been employed to generate hybrid inorganic-organic network materials. Unique ceramers were prepared based on an alkoxysilane functionalized soft organic oligomer, poly(propylene oxide (PPO), and tetramethoxysilane (TMOS). Despite the formation of covalent bonds between the inorganic and organic constituents, the resulting network materials were phase separated, composed of a silicate rich phase embedded in a matrix of the organic oligomer chains. The behavior of such materials was similar to elastomers containing a reinforcing filler. The study focused on the influence of initial oligomer molecular weight, functionality, and tetramethoxysilane, water, and acid catalyst content on the final structure, mechanical and thermal properties. The sol-gel approach has also been exploited to generate thin, transparent, abrasion resistant coatings for metal substrates. These systems were based on alkoxysilane functionalized diethylenetriamine (DETA) with TMOS, which generated hybrid networks with very high crosslink densities. These materials were applied with great success as abrasion resistant coatings to aluminum, copper, brass, and stainless steel. In another study, intercalated polymer-clay nanocomposites were prepared based on various epoxy networks montmorillonite clay. This work explored the influence of incorporated clay on the adhesive properties of the epoxies. The lap shear strength decreased with increasing day content This was due to a reduction in the toughness of the epoxy. Also, the delaminated (or exfoliated) nanocomposite structure could not be generated. Instead, all nanocomposite systems possessed an intercalated structure. The final project involved the characterization of a series of metallocene catalyzed linear polyethylenes, produced at Phillips Petroleum. Polyolefins synthesized with such new catalyst systems are becoming widely available. The influence of molecular weight and thermal treatment on the mechanical, rheological

  2. Effect of SiO2 on the Abrasion Resistance of E-coatings on Magnesium Alloy%SiO2对镁合金阴极电泳涂层耐磨性的影响

    Institute of Scientific and Technical Information of China (English)

    朱阮利; 张津; 高帅; 倪娜

    2015-01-01

    ABSTRACT:Objective To improve the abrasion resistance of organic coating on magnesium alloys. Methods In this paper, SiO2 powders were modified with KH450 silane and dispersed in electrophoretic paint. The surface of magnesium alloys was modified by KH460 silane,and then composite cathode electrophoresis coatings were prepared on it. The pencil hardness test, friction and wear test, circle adhesion method,NMP ( n methyl pyrrolidone) test and Machu test were taken to value the hardness, wear resistance, adhesion, anti-swelling properties of NMP and corrosion resistance of electrophoresis cathode coatings, respectively. Their morphol-ogies were studied by SEM and optical microscopy ( OM) . Results The pencil hardness of the coating,which was prepared on the magnesium alloy modified with KH460, was improved from 4H to 5H by adding SiO2 powders and the corrosion resistance was also increased. And their adhesion and anti-swelling properties of NMP were still kept at 1 class and >120 h respectively. The original coating and the coating containing Nano SiO2 powder, both prepared on the magnesium alloy modified with KH460, had good wear resistance, and their ratios of wear scar depth and coating thickness were 0. 47 and 0. 475 respectively, their friction coefficients were lower than 0. 4. The coating prepared directly on magnesium alloy and the coating containing Micron SiO2 powder prepared on the magnesium alloy modified with KH460 had poor wear resistance, and their ratios of wear scar depth and coating thickness were 0. 665 and 0. 673 respectively, friction coefficients of them were higher than 0. 7. The mainly wear failure mechanism of the four coatings was fatigue failure. Conclusion The addition of SiO2 powder can improve the corrosion resistance and pencil hardness of coatings effectively, and did not decrease adhesion and anti-swelling properties of NMP. The pretreatment of magnesium alloy with silane and the addition of Nano SiO2 in the electrophoretic paint can

  3. Abrasive wear behaviors of high velocity arc sprayed iron aluminum composite coatings

    Institute of Scientific and Technical Information of China (English)

    Weipu Xu; Binshi Xu; Wei Zhang; Zixin Zhu; Yixiong Wu

    2005-01-01

    The High Velocity Arc Spraying (HVAS) technology was used to prepare Fe-Al composite coatings by the adding of different elements into cored wires to obtain different Fe-Al coatings. The added compounds do great effect on the properties of the composite coatings. The microstructures and abrasive wear performances of the coatings were assessed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and THT07-135 high temperature wear equipment. It was found that the adding of Cr3C2 can greatly increase the room temperature wear behavior, and Fe-Al/WC coatings have adapting periods at the beginning of wear experiment. With the rise of temperature, the wear resistance of Fe-Al/Cr3C2 coatings becomes bad from room temperature to 250℃, and then stable from 250℃ to 550℃; the wear resistance of Fe-Al/WC becomes well with the rise of temperature.The adding of Cr and Ni can also improve wear performances of Fe-Al composite coatings.

  4. Formation of abrasion-resistant coatings of the AlSiFe{sub x}Mny intermetallic compound type on the AISI 304L alloy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Peralez, L. G.; Flores-Valdes, A.; Salinas-Rodriguez, A.; Ochoa-Palacios, R. M.; Toscano-giles, J. A.; Torres-Torres, J.

    2016-05-01

    The α-Al{sub 9}FeMnSi and α-Al{sub 9}FeMn{sub 2}Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 degree centigrade), pressure (5, 10 y 20 MPa) and holding time (3600, 5400 y 7200 seconds). Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 degree centigrade, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of β-Al{sub 9}FeMnSi and β-Al{sub 9}FeMn{sub 2}Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface. (Author)

  5. Gears castings from ductile iron of improved abrasion wear resistance

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2011-10-01

    Full Text Available The aim of this study was to develop an industrial technological process for the manufacturing of castings from alloyed ductile iron characterized by improved resistance to abrasion wear. The outcome of the study was the implementation of developed technology under the industrial conditions of ASPAMET Foundry Plant and start up of production of a wide range of cast gears.

  6. ANN & ANFIS Models for Prediction of Abrasive Wear of 3105 Aluminium Alloy with Polyurethane Coating

    Directory of Open Access Journals (Sweden)

    H. Alimam

    2016-06-01

    Full Text Available The quest for safety and reliability has increased significantly after Industrial revolution, so is the case for coating industries. In this paper 3105 Aluminium alloy sheet is coated with organic polyurethane coating. After the implementation of coating, various processes are undergone to check its reliability under elevated conditions. ANN & ANFIS model were developed and trained with an objective to find abrasive wear during the process. ANN & ANFIS model were compared with the experimental results. It is observed that the abrasive wear of a coated specimen can be predicted accurately and precisely using ANN and ANFIS models.

  7. Formation of abrasion-resistant coatings of the AlSiFexMny intermetallic compound type on the AISI 304L alloy

    Directory of Open Access Journals (Sweden)

    Martínez-Perales, Laura G.

    2016-03-01

    Full Text Available The α-Al9FeMnSi and β-Al9FeMn2Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 °C, pressure (5, 10 y 20 MPa and holding time (3600, 5400 y 7200 seconds. Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 °C, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of α-Al9FeMnSi and β-Al9FeMn2Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface.Los intermetálicos α-Al9FeMnSi y β-Al9FeMn2Si formados por sinterización reactiva de polvos Al, Si, Mn, Fe, Cr, Ni se han utilizado en aceros AISI 304L para mejorar la microdureza. Las variables de procesamiento de sinterización reactiva fueron temperatura (600, 650, 700, 750, y 800 °C, presión (5, 10 y 20 MPa y el tiempo de retención (3600, 5400 7200 segundos. Los resultados experimentales muestran que la temperatura es la variable más importante que afecta a la formación del sustrato/recubrimiento, mientras que la presión no parece tener un efecto significativo una influencia significativa. Los resultados muestran las condiciones óptimas de la sinterización reactiva que favorecen la formación del sustrato/recubrimiento a 800 °C, 20 MPa y 7200 segundos. En estas condiciones, la zona de reacción entre el sustrato y el recubrimiento es más compacta y bien

  8. Microstructure formation and properties of abrasion resistant cast steel

    OpenAIRE

    S. Parzych; Krawczyk, J.

    2010-01-01

    The so-called adamitic cast steels are characterised by a high abrasion resistance. These cast steels are of a pearlitic matrix with uniformly distributed hypereutectoid cementite precipitates. Apart from hypereutectoid cementite very often transformed ledeburite also occurs in the microstructure of these cast steels. Such cast steels contain chromium (app. 1 %) and nickel (app. 0.5 %) as alloy additions and sometimes their silicon content is increased. The presence of molybdenum is also perm...

  9. The Comparative Effect of Sugarcane Juice on the Abrasion-Corrosion Behavior of Fe-Cr-B Electric Arc Sprayed and Fe-Cr-C Weld Coatings

    Science.gov (United States)

    Buchanan, Vernon E.

    2012-02-01

    Abrasion-corrosion tests were conducted on two commonly Fe-Cr-C shielded metal arc welding (SMAW) hardfacings used in the sugar industry and an arc sprayed Fe-Cr-based coating. The tests were performed on a modified block-on-ring tester with the coatings sliding against compressed sugarcane fiber in the presence of abrasive slurry. The findings showed that, in the presence of sugarcane juice and sand slurry, the SMAW coatings had similar wear performance while the abrasive wear of the arc-sprayed coating was superior to the SMAW coatings. In the presence of a neutral solution, the material loss from the arc-sprayed coating was similar to that obtained in the sugarcane juice while the SMAW coatings showed a marked decrease; this demonstrated that the arc-sprayed coating was more desirable in an abrasive-corrosion environment. The study also showed that the resistance to material does not follow the expected trend, in which wear resistance increases with increasing hardness.

  10. Studies on broad spectrum corrosion resistant oxide coatings

    Indian Academy of Sciences (India)

    Someswar Datta

    2001-12-01

    The corrosion resistant oxide coatings, developed and applied by the conventional vitreous enamelling techniques, showed superior resistance to a range of mineral acids at various strengths and temperatures, alkaline solutions, boiling water and chrome plating solutions. These coatings possess considerable abrasion and impact resistance as well as high thermal shock resistance. The properties of the coating system have been studied in detail and found to be strongly dependent on composition and processing parameters. These coatings have been characterized by X-ray diffraction analysis and SEM studies. Some of the coating materials have been found to be biocompatible.

  11. Standard Test Method for Abrasive Wear Resistance of Cemented

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of abrasive wear resistance of cemented carbides. 1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units are in parentheses and may be approximate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  12. Erosion-resistant coatings for gas turbine compressor blades

    Science.gov (United States)

    Muboyadzhyan, S. A.

    2009-06-01

    The effect of ion-plasma coatings made from high-hardness metal compounds on the erosion and corrosion resistance and the mechanical properties of alloy (substrate) + coating compositions is comprehensively studied. The effects of the thickness, composition, deposition conditions, and design of coatings based on metal nitrides and carbides on the relative gas-abrasive wear of alloy + coating compositions in a gas-abrasive flux are analyzed. The flux contains quartz sand with an average fraction of 300-350 μm; the abrasive feed rate is 200 g/min; and the angles of flux incidence are 20° (tangential flow) and 70° (near-head-on attack flow). Alloy + coating compositions based on VN, VC, Cr3C2, ZrN, and TiN coatings 15-30 μ m thick or more are shown to have high erosion resistance. A detailed examination of the coatings with high erosion resistance demonstrates that a zirconium nitride coating is most appropriate for protecting gas turbine compressor blades made of titanium alloys; this coating does not decrease the fatigue strength of these alloys. A chromium carbide coating is the best coating for protecting compressor steel blades.

  13. Polyurethanes from the crystalline prepolymers resistant to abrasive wear

    Directory of Open Access Journals (Sweden)

    Domańska Agata

    2014-12-01

    Full Text Available The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether glycol (PTMEG, as well as from two different isocyanates 4,4′-methylenebis(cyclohexylisocyanate (HMDI and 4.4′-methylenebis(phenyl isocyanate (MDI in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyurethane surface wettability, friction coefficient for different couples of the co-working materials such as polyurethane-polyurethane, polyurethane-titanium alloy, polyurethane-alumina, in comparison to commonly used polyethylene-titanium alloy. Shear strength of polyurethane-alumina joint, as well as viscosity of prepolymers were also measured. The values of friction coefficient were compared to literature data on commercially available polyurethane with the trade name Pellethane. Polyurethanes obtained are characterized by low abrasive wear and low friction coefficient in couple with the titanium alloy, what makes them attractive as possible components of ceramic-polymer endoprosthesis joints.

  14. Preparation of spherical ceria coated silica nanoparticle abrasives for CMP application

    Energy Technology Data Exchange (ETDEWEB)

    Peedikakkandy, Lekha [Department of Metallurgical Engineering and Materials Science, IIT Bombay, Powai, Mumbai 400076 (India); Kalita, Laksheswar [Advanced Technology Group, Applied Materials India Pvt. Ltd., Department of Electrical Engineering, IIT Bombay, Powai, Mumbai 400076 (India); Kavle, Pravin [Department of Metallurgical Engineering and Materials Science, IIT Bombay, Powai, Mumbai 400076 (India); Kadam, Ankur; Gujar, Vikas; Arcot, Mahesh [Advanced Technology Group, Applied Materials India Pvt. Ltd., Department of Electrical Engineering, IIT Bombay, Powai, Mumbai 400076 (India); Bhargava, Parag, E-mail: pbhargava@iitb.ac.in [Department of Metallurgical Engineering and Materials Science, IIT Bombay, Powai, Mumbai 400076 (India)

    2015-12-01

    Highlights: • Nano-layer coating of ceria over silica nanoparticles. • Study effect of reaction pH and temperature on ceria coating over silica nanoparticles. • CMP application of ceria coated silica nanoparticles over SiO{sub 2} and SiN films. - Abstract: This paper describes synthesis of spherical and highly mono-dispersed ceria coated silica nanoparticles of size ∼70–80 nm for application as abrasive particles in Chemical Mechanical Planarization (CMP) process. Core silica nanoparticles were initially synthesized using micro-emulsion method. Ceria coating on these ultrafine and spherical silica nanoparticles was achieved using controlled chemical precipitation method. Study of various parameters influencing the formation of ceria coated silica nanoparticles of size less than 100 nm has been undertaken and reported. Ceria coating over silica nanoparticles was varied by controlling the reaction temperature, pH and precursor concentrations. Characterization studies using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Energy Dispersive X-ray analysis show formation of crystalline CeO{sub 2} coating of ∼10 nm thickness over silica with spherical morphology and particle size <100 nm. Aqueous slurry of ceria coated silica abrasive was prepared and employed for polishing of oxide and nitride films on silicon substrates. Polished films were studied using ellipsometry and an improvement in SiO{sub 2}:SiN selective removal rates up to 12 was observed using 1 wt% ceria coated silica nanoparticles slurry.

  15. The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

    OpenAIRE

    Xu, X.

    2016-01-01

    The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous abrasion process and unravel abrasion damage formation in construction steels, i.e. carrying out scratch tests using a large indenter with different pre-loads to generate a wide pre-scratch with sta...

  16. On the Durability and Wear Resistance of Transparent Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Ilker S. Bayer

    2017-01-01

    Full Text Available Transparent liquid repellent coatings with exceptional wear and abrasion resistance are very demanding to fabricate. The most important reason for this is the fact that majority of the transparent liquid repellent coatings have so far been fabricated by nanoparticle assembly on surfaces in the form of films. These films or coatings demonstrate relatively poor substrate adhesion and rubbing induced wear resistance compared to polymer-based transparent hydrophobic coatings. However, recent advances reported in the literature indicate that considerable progress has now been made towards formulating and applying transparent, hydrophobic and even oleophobic coatings onto various substrates which can withstand certain degree of mechanical abrasion. This is considered to be very promising for anti-graffiti coatings or treatments since they require resistance to wear abrasion. Therefore, this review intends to highlight the state-of-the-art on materials and techniques that are used to fabricate wear resistant liquid repellent transparent coatings so that researchers can assess various aptitudes and limitations related to translating some of these technologies to large scale stain repellent outdoor applications.

  17. Microstructure formation and properties of abrasion resistant cast steel

    Directory of Open Access Journals (Sweden)

    S. Parzych

    2010-01-01

    Full Text Available The so-called adamitic cast steels are characterised by a high abrasion resistance. These cast steels are of a pearlitic matrix with uniformly distributed hypereutectoid cementite precipitates. Apart from hypereutectoid cementite very often transformed ledeburite also occurs in the microstructure of these cast steels. Such cast steels contain chromium (app. 1 % and nickel (app. 0.5 % as alloy additions and sometimes their silicon content is increased. The presence of molybdenum is also permissible (app. 0.4 %. The basic problem in application of these steels for structural elements constitutes their insufficient crack resistance. An improvement of mechanical properties by changes of morphology of hypereutectoid cementite and transformed ledeburite precipitates by means of the heat treatment application was the aim of this study. G200CrNiMo4-3-3 cast steel was the investigated material. Changes in the morphology of hypereutectoid cementite and transformed ledeburite obtained due to the heat treatment are described in detail in the present paper. An influence of the microstructure changes on impact toughness of the investigated cast steel is presented. Investigations performed within this study will serve for the microstructure optimisation on account of functional qualities of this cast steel.

  18. Halogen-Free Phosphonate Ionic Liquids as Precursors of Abrasion Resistant Surface Layers on AZ31B Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Tulia Espinosa

    2015-01-01

    Full Text Available Surface coatings formed by immersion in the ionic liquids (ILs 1,3-dimethylimidazolium methylphosphonate (LMP101, 1-ethyl-3-methylimidazolium methylphosphonate (LMP102 and 1-ethyl-3-methylimidazolium ethylphosphonate (LEP102 on magnesium alloy AZ31B at 50 °C have been studied. The purpose of increasing the temperature was to reduce the immersion time, from 14 days at room temperature, to 48 hours at 50 °C. The abrasion resistance of the coated alloy was studied by microscratching under progressively increasing load, and compared with that of the uncoated material. The order of abrasion resistance as a function of the IL is LEP102 > LMP101 > LMP102, which is in agreement with the order obtained for the coatings grown at room temperature. The maximum reduction in penetration depth with respect to the uncovered alloy, of a 44.5%, is obtained for the sample treated with the ethylphosphonate LEP102. However, this reduction is lower than that obtained when the coating is grown at room temperature. This is attributed to the increased thickness and lower adhesion of the coatings obtained at 50 °C, particularly those obtained from methylphosphonate ionic liquids. The results are discussed from SEM-EDX and profilometry.

  19. Behavior of HVOF WC-10Co4Cr Coatings with Different Carbide Size in Fine and Coarse Particle Abrasion

    Science.gov (United States)

    Ghabchi, Arash; Varis, Tommi; Turunen, Erja; Suhonen, Tomi; Liu, Xuwen; Hannula, S.-P.

    2010-01-01

    A modified ASTM G 65 rubber wheel test was employed in wet and dry conditions using 220 nm titania particles and 368 μm sand particles, respectively. Both tests were conducted on WC-CoCr coatings produced with two powders with different carbide grain sizes (conventional and sub-micron) to address the effect of carbide size and abrasive medium characteristics on the wear performance. The same spot before and after the wet abrasion wear testing was analyzed in detail using SEM to visualize wear mechanisms. It was shown that the wear mechanism depends on the relative size of the carbide and abrasive particles. Wear mechanisms in dry sand abrasion were studied by analyzing the single scratches formed by individual abrasive particles. Interaction of surface open porosity with moving abrasive particles causes formation of single scratches. By tailoring the carbide size, the wear performance can be improved.

  20. Wear resistance of WC/Co HVOF-coatings and galvanic Cr coatings modified by diamond nanoparticles

    Science.gov (United States)

    Kandeva, M.; Grozdanova, T.; Karastoyanov, D.; Assenova, E.

    2017-02-01

    The efforts in the recent 20 years are related to search of ecological solutions in the tribotechnologies for the replacement of galvanic Cr coatings in the contact systems operating under extreme conditions: abrasion, erosion, cavitation, corrosion, shock and vibration loads. One of the solutions is in the composite coatings deposited by high velocity gas-flame process (HVOF). The present paper presents comparative study results for mechanical and tribological characteristics of galvanic Cr coatings without nanoparticles, galvanic Cr coatings modified by diamond nanoparticles NDDS of various concentration 0.6; 10; 15 и 20% obtained under three technological regimes, and composite WC-12Co coating. Comparative results about hardness, wear, wear resistance and friction coefficient are obtained for galvanic Cr-NDDS and WC-12Co coatings operating at equal friction conditions of dry friction on abrasive surface. The WC-12Co coating shows 5.4 to 7 times higher wear resistance compared to the galvanic Cr-NDDS coatings.

  1. Characterization of the Micro-Abrasive Wear in Coatings of TaC-HfC/Au for Biomedical Implants

    Directory of Open Access Journals (Sweden)

    Pablo Guzmán

    2017-07-01

    Full Text Available The object of this work was the deposition of a Ta-Hf-C thin film with a gold interlayer on stainless steel, via the physical vapor deposition (PVD technique, in order to evaluate the properties of different systems subjected to micro-abrasive wear phenomena generated by alumina particles in Ringer's solution. The surface characterization was performed using a scanning electron microscope (SEM and atomic force microscope (AFM. The crystallographic phases exhibited for each coating were obtained by X-ray diffraction (XRD. As a consequence of modifying the composition of Ta-Hf there was evidence of an improvement in the micro-abrasive wear resistance and, for each system, the wear constants that confirm the enhancement of the surface were calculated. Likewise, these surfaces can be bioactive, generating an alternative to improve the biological fixation of the implants, therefore, the coatings of TaC-HfC/Au contribute in the development of the new generation of orthopedic implants.

  2. 新型改性脂肪胺固化剂的合成及其在管道减阻耐磨无溶剂涂料中的应用%Synthesis of A New Modified Aliphatic Amine Curing Agent and Its Application in Abrasion Resistant Solventless Coatings for Pipeline Drag Reduction

    Institute of Scientific and Technical Information of China (English)

    粟鹰; 廖有为; 李芳; 丁武斌

    2012-01-01

    合成了一种新型的改性脂肪胺固化剂,并以此制备了用于天然气管道减阻耐磨的无溶剂涂料。该固化剂赋予涂层优良的机械性能、良好的耐盐雾性和耐化学介质浸泡性。通过电化学阻抗谱对该涂层的耐腐蚀性进行了评价,并对其减阻效果进行了研究。%A abrasion resistant solventless coatings for pipeline drag reduction was prepared by the new modified aliphatic amine curing agent, which was synthesized in this article. The film has excellent mechanical properties, salt fog resistance and chemicals resistance. Through electrochemical impedance spectroscopy, its corrosion resistance was evaluated. And its drag reduction effect was also researched.

  3. Self-healing Characteristics of Collagen Coatings with Respect to Surface Abrasion

    Science.gov (United States)

    Kim, Chang-Lae; Kim, Dae-Eun

    2016-03-01

    A coating based on collagen with self-healing properties was developed for applications in mechanical components that are prone to abrasion due to contact with a counter surface. The inherent swelling behavior of collagen in water was exploited as the fundamental mechanism behind self-healing of a wear scar formed on the surface. The effects of freeze-drying process and water treatment of the collagen coatings on their mechanical and self-healing properties were analyzed. Water was also used as the medium to trigger the self-healing effect of the collagen coatings after the wear test. It was found that collagen coatings without freeze-drying did not demonstrate any self-healing effect whereas the coatings treated by freeze-drying process showed remarkable self-healing effect. Overall, collagen coatings that were freeze-dried and water treated showed the best friction and self-healing properties. Repeated self-healing ability of these coatings with respect to wear scar was also demonstrated. It was also confirmed that the self-healing property of the collagen coating was effective over a relatively wide range of temperature.

  4. Self-healing Characteristics of Collagen Coatings with Respect to Surface Abrasion.

    Science.gov (United States)

    Kim, Chang-Lae; Kim, Dae-Eun

    2016-03-24

    A coating based on collagen with self-healing properties was developed for applications in mechanical components that are prone to abrasion due to contact with a counter surface. The inherent swelling behavior of collagen in water was exploited as the fundamental mechanism behind self-healing of a wear scar formed on the surface. The effects of freeze-drying process and water treatment of the collagen coatings on their mechanical and self-healing properties were analyzed. Water was also used as the medium to trigger the self-healing effect of the collagen coatings after the wear test. It was found that collagen coatings without freeze-drying did not demonstrate any self-healing effect whereas the coatings treated by freeze-drying process showed remarkable self-healing effect. Overall, collagen coatings that were freeze-dried and water treated showed the best friction and self-healing properties. Repeated self-healing ability of these coatings with respect to wear scar was also demonstrated. It was also confirmed that the self-healing property of the collagen coating was effective over a relatively wide range of temperature.

  5. Microstructure, Mechanical Properties, and Two-Body Abrasive Wear Behavior of Cold-Sprayed 20 vol.% Cubic BN-NiCrAl Nanocomposite Coating

    Science.gov (United States)

    Luo, Xiao-Tao; Yang, Er-Juan; Shang, Fu-Lin; Yang, Guan-Jun; Li, Chen-Xin; Li, Chang-Jiu

    2014-10-01

    20 vol.% cubic boron nitride (cBN) dispersoid reinforced NiCrAl matrix nanocomposite coating was prepared by cold spray using mechanically alloyed nanostructured composite powders. The as-sprayed nanocomposite coating was annealed at a temperature of 750 °C to enhance the inter-particle bonding. Microstructure of spray powders and coatings was characterized. Vickers microhardness of the coatings was measured. Two-body abrasive wear behavior of the coatings was examined on a pin-on-disk test. It was found that, in mechanically alloyed composite powders, nano-sized and submicro-sized cBN particles are uniformly distributed in nanocrystalline NiCrAl matrix. Dense coating was deposited by cold spray at a gas temperature of 650 °C with the same phases and grain size as those of the starting powder. Vickers hardness test yielded a hardness of 1063 HV for the as-sprayed 20 vol.% cBN-NiCrAl coating. After annealed at 750 °C for 5 h, unbonded inter-particle boundaries were partially healed and evident grain growth of nanocrystalline NiCrAl was avoided. Wear resistance of the as-sprayed 20 vol.% cBN-NiCrAl nanocomposite coating was comparable to the HVOF-sprayed WC-12Co coating. Annealing of the nanocomposite coating resulted in the improvement of wear resistance by a factor of ~33% owing to the enhanced inter-particle bonding. Main material removal mechanisms during the abrasive wear are also discussed.

  6. Preparation and Properties of High Hardness and Oxidation Resisting Coating Using Electric Arc Spray

    Institute of Scientific and Technical Information of China (English)

    LIZhuo-xin; CUILi; WANGJiang-ping; TANGChun-tian

    2004-01-01

    A coating with high hardness, wear and oxidation resistance was prepared by electric arc spray. The hardness, bonding strength, abrasive wear and values of porosity and oxidation resistance of the coating were investigated. The microstructures and function of Cr3C2 of the coating were analyzed. The results showed surface Rockness Hardness HR30 reached 72.5 and average bond strength reached 49.1Mpa. Also porosity value was less than 2%. In addition, it was found from the comparison between the coating and 45CT coating that, oxidation resistance of the coating was less than that of 45CT, but the abrasive wear of the coating was obvious better than that of 45CT.

  7. Preparation and Properties of High Hardness and Oxidation Resisting Coating Using Electric Arc Spray

    Institute of Scientific and Technical Information of China (English)

    LI Zhuo-xin; CUI Li; WANG Jiang-ping; TANG Chun-tian

    2004-01-01

    A coating with high hardness, wear and oxidation resistance was prepared by electric arc spray. The hardness,bonding strength, abrasive wear and values of porosity and oxidation resistance of the coating were investigated. The microstructures and function of Cr3C2 of the coating were analyzed. The results showed surface Rockness Hardness HR30 reached 72.5 and average bond strength reached 49.1Mpa. Also porosity value was less than 2%. In addition, it was found from the comparison between the coating and 45CT coating that, oxidation resistance of the coating was less than that of 45CT, but the abrasive wear of the coating was obvious better than that of 45CT.

  8. The effect of heat treatment on the gouging abrasion resistance of alloy white cast irons

    Science.gov (United States)

    Are, I. R. S.; Arnold, B. K.

    1995-02-01

    A series of heat treatments was employed to vary the microstructure of four commercially important alloy white cast irons, the wear resistance of which was then assessed by the ASTM jaw-crusher gouging abrasion test. Compared with the as-cast condition, standard austenitizing treatments produced a substantial increase in hardness, a marked decrease in the retained aus-tenite content in the matrix, and, in general, a significant improvement in gouging abrasion resistance. The gouging abrasion resistance tended to decline with increasing austenitizing tem-perature, although the changes in hardness and retained austenite content varied, depending on alloy composition. Subcritical heat treatment at 500 ° following hardening reduced the retained austenite content to values less than 10 pct, and in three of the alloys it caused a significant fall in both hardness and gouging abrasion resistance. The net result of the heat treatments was the development of optimal gouging abrasion resistance at intermediate levels of retained aus-tenite. The differing responses of the alloys to both high-temperature austenitizing treatments and to subcritical heat treatments at 500 ° were related to the effects of the differing carbon and alloying-element concentrations on changes in the M s temperature and secondary carbide precipitation.

  9. Abrasion Resistance of as-Cast High-Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Pokusová Marcela

    2014-12-01

    Full Text Available High chromium cast irons are widely used as abrasion resistant materials. Their properties and wear resistance depend on carbides and on the nature of the matrix supporting these carbides. The paper presents test results of irons which contain (in wt.% 18-22 Cr and 2-5 C, and is alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve the toughness. Tests showed as-cast irons with mostly austenitic matrix achieved hardness 36-53 HRC but their relative abrasion-resistance was higher than the tool steel STN 19436 heat treated on hardness 60 HRC.

  10. Structural transformations in wear resistance of iron- and cobalt-based amorphous alloys during abrasive wear

    Science.gov (United States)

    Korshunov, L. G.; Shabashov, V. A.; Chernenko, N. L.

    2010-04-01

    The wear resistance and structural changes in a number of amorphous alloys based on iron and cobalt and in high-carbon tool steels are studied during wear by a fixed abrasive (crondum, Carborundum) at room temperature and -196°C. The abrasive wear resistance of the amorphous alloys is shown to be 1.6-3.1 lower than that of the high-carbon tool steels having a similar hardness. The relatively low level of the abrasive wear resistance of the amorphous alloys is assumed to be caused by strain softening of their surface during wear. A nanocrystalline structure is found to form in local microvolumes in a thin deformed surface layer of the alloys.

  11. The Abrasion Resistance and Adhesion of Hfcvd Boron and Silicon-Doped Diamond Films on WC-Co Drawing Dies

    Science.gov (United States)

    Wang, Liang; Liu, Jinfei; Tang, Tang; Sun, Fanghong; Xie, Nan

    Diamond films have been deposited on the interior hole surface of cobalt-cemented tungsten carbide (WC-Co) drawing dies from acetone, trimethyl borate (C3H9BO3), tetraethoxysilane (C8H20O4Si, TEOS) and hydrogen mixture by hot-filament chemical vapor deposition (HFCVD) method. The structures and quality of as-deposited diamond films are characterized with field-emission scanning electron microscopy (FESEM) and Raman spectroscopy. The abrasion ratio and the adhesive strength of as-deposited diamond films are evaluated by copper wire drawing tests and ultrasonic lapping tests, respectively. The results suggest that diamond films with small grain size and high growth rate can be obtained due to the mutual effects of boron and silicon impurities in the gas phases. The results of ultrasonic lapping tests show that diamond films doped with boron and/or silicon can bear the severe erosion of the large diamond powder. Diamond films peeling off within the reduction zone of the drawing dies cannot be observed after testing of 2h. The abrasion ratio of boron and silicon-added diamond films is five times that of diamond films without any addition. Adding boron and/or silicon in the diamond films is proved to be an efficient way to obtain high-adhesive-strength and high-abrasion-resistance diamond-coated drawing dies.

  12. Corrosion resistant coating

    Science.gov (United States)

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  13. Microstructure and abrasive wear properties of M(Cr,Fe7C3 carbides reinforced high-chromium carbon coating produced by gas tungsten arc welding (GTAW process

    Directory of Open Access Journals (Sweden)

    Soner BUYTOZ

    2010-01-01

    Full Text Available In the present study, high-chromium ferrochromium carbon hypereutectic alloy powder was coated on AISI 4340 steel by the gas tungsten arc welding (GTAW process. The coating layers were analyzed by optical microscopy, X-ray diffraction (XRD, field-emission scanning electron microscopy (FE-SEM, X-ray energy-dispersive spectroscopy (EDS. Depending on the gas tungsten arc welding pa-rameters, either hypoeutectic or hypereutectic microstructures were produced. Wear tests of the coatings were carried out on a pin-on-disc apparatus as function of contact load. Wear rates of the all coating layers were decreased as a function of the loading. The improvement of abrasive wear resistance of the coating layer could be attributed to the high hardness of the hypereutectic M7C3 carbides in the microstruc-ture. As a result, the microstructure of surface layers, hardness and abrasive wear behaviours showed different characteristics due to the gas tungsten arc welding parameters.

  14. The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

    NARCIS (Netherlands)

    Xu, X.

    2016-01-01

    The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous a

  15. Coatings for improved corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1992-05-01

    Several coating approaches are being developed to resist attack in coal-fired environments and thereby minimize corrosion of underlying substrate alloys and extend the time for onset of breakaway corrosion. In general, coating systems can be classified as either diffusion or overlay type, which are distinguished principally by the method of deposition and the structure of the resultant coating-substrate bond. The coating techniques examined are pack cementation, electrospark deposition, physical and chemical vapor deposition, plasma spray, and ion implantation. In addition, ceramic coatings are used in some applications.

  16. Influence on the wear resistance of the particle size used in coatings of Alumina

    Science.gov (United States)

    Santos, A.; Guzmán, R.; Ramirez, Z. Y.

    2017-01-01

    In the literature, it is common to find that the size of the particles used in coatings through thermal spraying processes influences the hardness and wear resistance thereof; this project aimed to quantify the importance of this parameter in the adhesive and abrasive wear resistance when aluminium oxide is deposited on a substrate of AISI 1020 steel, through a thermal spraying by flame process. The methodology consisted of: a) morphological characterization of the powder used in the coatings by scanning electron microscopy, b) deposition of coatings, c) testing of adhesive and abrasive wear (ASTM G99-05 Standard test method for wear testing with a pin-on-disk apparatus and ASTM G65–04 Standard test method for measuring abrasion using dry sand/rubber wheel apparatus), and d) statistical analysis to determine the influence of particle size on wear resistance. The average size of the powder used for coatings was 92, 1690, 8990 and 76790nm. The obtained results allow to identify an inversely proportional behaviour between particle size and wear resistance, in both types of wear (adhesive and abrasive) is shown a logarithmic trend indicating an increase in loss mass during the test as the particle size is also increased and therefore a decrease in wear resistance of the coating.

  17. Structural transformations and wear resistance of abrasive-affected amorphous Fe- and Co-based alloys

    Science.gov (United States)

    Korshunov, L. G.; Chernenko, N. L.

    2008-12-01

    The abrasive wear resistance of the Fe64Co30Si3B3, Fe82.6Nb5Cu3Si8B1.4, Co86.5Cr4Si7B2.5, and Fe81Si4B13C2 amorphous alloys (ribbon 30 μm thick) has been investigated upon sliding over fixed abrasives (corundum and silicon carbide). The character of fracture of the surface and structural transformations initiated in these materials by the abrasive action have been studied by the metallographic, X-ray diffraction, and electron-microscopic methods. It has been shown that the abrasive wear resistance of the amorphous alloys is smaller by a factor of 1.6-2.9 than that of the Kh12M and U8 tool steels possessing approximately the same level of hardness. A pronounced softening of the surface layer of the amorphous alloys in the process of wear, which is characterized by a decrease in their microhardness reaching 12.5%, has been found. It has been shown that in the surface layer of these amorphous alloys upon wear there arises a small amount (on the order of several volume percent) of the nanocrystalline structure, which does not exert a marked effect on the microhardness and wear resistance of the alloys. In the alloys under study, the main factor that is responsible for their comparatively low abrasive wear resistance is their local softening in the process of wear caused by specific features of deformation processes occurring heterogeneously under the action of high shear contact stresses.

  18. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  19. High temperature resistant cermet and ceramic compositions. [for thermal resistant insulators and refractory coatings

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1978-01-01

    High temperature oxidation resistance, high hardness and high abrasion and wear resistance are properties of cermet compositions particularly to provide high temperature resistant refractory coatings on metal substrates, for use as electrical insulation seals for thermionic converters. The compositions comprise a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride are also described.

  20. Laser cladding of Zr-based coating on AZ91D magnesium alloy for improvement of wear and corrosion resistance

    Indian Academy of Sciences (India)

    Kaijin Huang; Xin Lin; Changsheng Xie; T M Yue

    2013-02-01

    To improve the wear and corrosion resistance of AZ91D magnesium alloy, Zr-based coating made of Zr powder was fabricated on AZ91D magnesium alloy by laser cladding. The microstructure of the coating was characterized by XRD, SEM and TEM techniques. The wear resistance of the coating was evaluated under dry sliding wear test condition at room temperature. The corrosion resistance of the coating was tested in simulated body fluid. The results show that the coating mainly consists of Zr, zirconium oxides and Zr aluminides. The coating exhibits excellent wear resistance due to the high microhardness of the coating. The main wear mechanism of the coating and the AZ91D sample are different, the former is abrasive wear and the latter is adhesive wear. The coating compared to AZ91D magnesium alloy exhibits good corrosion resistance because of the good corrosion resistance of Zr, zirconium oxides and Zr aluminides in the coating.

  1. Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing

    Science.gov (United States)

    Bressan, José Divo; Schopf, Roberto Alexandre

    2011-05-01

    Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.

  2. Relationship among wear-resistance of three-body abrasion,substructure and property in martensite steels

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of subsurface hardness on wear-resistance of martensitic steel 20Cr, 40CrSi, 60Mn, T8 and T10 in three-body abrasion under static load was investigated. It shows that the characteristic ofthe subsurface hardness distribution and the abrasive wear resistanceis related to the substructure near the worn surface. The substructure of the tested martensite steel has an apparent relationship with thecarbon content and steels with moderate carbon content and hardness exhibit good resistance to abrasive wear. The competition of the work-hardening effect and the temper softening effect, which resulted from deformation and friction heat generating during abrasive wear is considered to be a main reason for the relation among wear-resistance, hardness and substructure. At the test conditions, the wear-resistance of 40CrSi is the best.

  3. Relations of abrasion resistance and hardness of 16Cr-3C white irons with retained austenite content

    Institute of Scientific and Technical Information of China (English)

    Zhiping Sun; Rulin Zuo; Cong Li; Baoluo Shen; Shengji Gao; Sijiu Huang

    2004-01-01

    The relationship between the retained austenite content of the matrix in 16Cr-3C white irons and the abrasion resistance was investigated. The results show that: (1) the abrasion resistance can be improved by sub-critical heat treatment, which could be attributed to the decrease of the retained austenite content; (2) both the abrasion resistance and hardness can be improved by controlling the retained austenite content below 20%-30% and arrive at the maximum when the retained austenite content is reduced to about 10%; (3) the abrasion resistance decreases abruptly once the retained austenite content is lower than 10%, which stems from both the in situ transformation of (Fe, Cr)23C6 to M3C carbides and the formation of pearlitic matrix.

  4. Corrosion-resistant metallic coatings

    OpenAIRE

    F. Presuel-Moreno; M.A. Jakab; N. Tailleart; Goldman, M.; J. R. Scully

    2008-01-01

    We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned) to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic i...

  5. Selected Plastics Wear Resistance to Bonded Abrasive Particles Compared to Some Ferrous Materials

    Directory of Open Access Journals (Sweden)

    Milan Brožek

    2015-01-01

    Full Text Available Plastics are macromolecular materials without we cannot imagine any branch of human activity with. Plastics have unique properties, often very different from metals. At the choice of the concrete plastic for the concrete application it is necessary to evaluate its mechanical, physical, chemical and technological properties. In last years producers offer also plastics for production of parts exposed to different types of wear. In the contribution the results of wear resistance studying of 10 types of plastics (PTFE, PVC, POM-C, PC, PETP, PEEK, PA66, PP, PA6E and PE-UHMW of one producer are published and compared with test results of four different Fe alloys (grey iron, structural steel, cast steel wear resistant and high-speed steel. The laboratory tests were carried out using the pin-on-disk machine with abrasive cloth (according to ČSN 01 5084, when the abrasive clothes of three different grits (240, 120 and 60 were used. It corresponds to the average abrasive grain sizes of 44.5 µm, 115.5 µm and 275 µm. During the test the test sample was pressed to the abrasive cloth by the pressure of 0.1 MPa. The wear intensity was assessed by the volume, weight and length losses of tested samples. The technical-economical evaluation was the part of the carried out tests. It was univocally proved that at the intensive abrasive wear using the abrasive cloth the best results shows the High-Speed Steel HSS Poldi Radeco 19 810 according to ČSN 41 9810, although its price is relatively high. Other tested Fe alloys, namely grey iron according to ČSN 42 2415, structural steel 11 373 according to ČSN 41 1373 and wear resistant cast steel VPH 6 showed also very favourable properties at the material low price. In comparison with Fe alloys the wear of all plastics was considerably higher and the plastics were considerably more expensive.

  6. Corrosion-resistant coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Kupp, D.M.; Martin, R.L. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  7. Examining of abrasion resistance of hybrid composites reinforced with SiC and Cgr particles

    Directory of Open Access Journals (Sweden)

    M. Łągiewka

    2008-08-01

    Full Text Available The presented work discusses the influence of the type and volume percentage of particulate reinforcement consisting of mixed silicon carbide and graphite on the abrasion wear of hybrid composites with AlMg10 matrix. Also the macro photos of frictional surfaces have been shown and the results of hardness measurements have been presented. The performed examinations have allowed for stating that the mixture of SiC and Cgr particles changes in favour the tribological properties of the matrix alloy. It has been also proved that introducing hard reinforcing particles along with soft lubricating ones allows for achieving the material exhibiting high abrasion resistance, and moreover, the graphite particles protect the abraded surface from the destructive action of silicon carbide particles. Also hardness measurements have been performed and the resulting conclusion is that the composite hardness increases with an increase in volume fraction of the reinforcing particles.

  8. Corrosion-resistant metallic coatings

    Directory of Open Access Journals (Sweden)

    F. Presuel-Moreno

    2008-10-01

    Full Text Available We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic inhibitors to protect defects in the coating, by formation of an optimized barrier to local corrosion in Cl− containing environments, as well as by sacrificial cathodic prevention. Further progress in this field could lead to the design of the next generation of adaptive or tunable coatings that inhibit corrosion of underlying substrates.

  9. The influence of aluminum and carbon on the abrasion resistance of high manganese steels

    Science.gov (United States)

    Buckholz, Samuel August

    Abrasive wear testing of lightweight, austenitic Fe-Mn-Al-C cast steel has been performed in accordance with ASTM G65 using a dry sand, rubber wheel, abrasion testing apparatus. Testing was conducted on a series of Fe-30Mn-XAl-YC-1Si-0.5Mo chemistries containing aluminum levels from 2.9 to 9.5 wt.% and carbon levels from 0.9 to 1.83 wt.%. Solution treated materials having an austenitic microstructure produced the highest wear resistance. Wear resistance decreased with higher aluminum, lower carbon, and higher hardness after age hardening. In the solution treated condition the wear rate was a strong function of the aluminum to carbon ratio and the wear rate increased with a parabolic dependence on the Al/C ratio, which ranged from 1.8 to 10.2. Examination of the surface wear scar revealed a mechanism of plowing during abrasion testing and this method of material removal is sensitive to work hardening rate. Work hardening behavior was determined from tensile tests and also decreased with increasing Al/C ratio and after aging hardening. The loss of wear resistance is related to short range ordering of Al and C in the solution treated materials and kappa-carbide precipitation in age hardened materials and both contribute to planar slip and lower work hardening rates. A high carbon tool steel (W1) and a bainitic low alloy steel (SAE 8620) were also tested for comparison. A lightweight steel containing 6.5 wt.% Al and 1.2 wt.% C has wear resistance comparable to within 5% of the bainitic SAE 8620 steel forging currently used for the Bradley Fighting Vehicle track shoe and this cast Fe-Mn-Al-C steel, at equivalent tensile properties, would be 10% lighter.

  10. An Research on Abrasion Resistance of Muzzle Shunt Rail Gun Rail Boronized with Self-protecting B4C Paste

    Institute of Scientific and Technical Information of China (English)

    HUJin-suo; CHENGShu-kang; ZHENGZhen-zhong; MAYuan; LIZhi-yuan

    2004-01-01

    Based on large numbers of experiments, together with some theoretic support such as equations related to the experiment, thermodynamic principles and so on, one useful and reasonable self-protecting boron formulation is got to reintorce the muzzle shunt rail gun rail. The preliminary friction and abrasion test results show that the formulation is acceptable and the abrasion resistance of the steel rail enhances to some extent after the surface reinforcement.

  11. An Research on Abrasion Resistance of Muzzle Shunt Rail Gun Rail Boronized with Self-protecting B4C Paste

    Institute of Scientific and Technical Information of China (English)

    HU Jin-suo; CHENG Shu-kang; ZHENG Zhen-zhong; MA Yuan; LI Zhi-yuan

    2004-01-01

    Based on large numbers of experiments, together with some theoretic support such as equations related to the experiment, thermodynamic principles and so on, one useful and reasonable self-protecting boron formulation is got to reinforce the muzzle shunt rail gun rail. The preliminary friction and abrasion test results show that the formulation is acceptable and the abrasion resistance of the steel rail enhances to some extent after the surface reinforcement.

  12. 喷涂型聚氨酯弹性体耐磨材料主要性能表征及影响因素分析%Performance Characterization and Influencing Factors Analysis of Spraying Abrasion-Resistance Polyurethane Elastomer

    Institute of Scientific and Technical Information of China (English)

    孟庆莉; 崔洪犁; 吴文文; 刘东晖

    2015-01-01

    The component A was synthesized by MDI and polyether polyol. The component B was composed by PPG, PTMG, diamine extender chain agent, abrasion⁃resisting additive, etc. Abrasion resistance polyurethane e⁃lastomer coating was prepared with component A and B by special spraying equipment. The effects of different poly⁃ether polyols and abrasion resisting additives on polyurethane elastomer coating were discussed. The four test meth⁃ods of spraying abrasion⁃resistance polyurethane elastomer under dry experimental conditions were introduced, in⁃cluding Akron abrasion, DIN abrasion, Taber abrasion and NBS abrasion. The relationship between these four kinds of abrasion was explained by experimental data. The abrasion⁃resisting additive A could reduce coefficient of friction obviously, the coefficient of kinetic friction was 0�321. PTMG could mostly improve the abrasion⁃resistance per⁃formance of spraying polyurethane elastomer coating, the Akron abrasion value was 0�030 cm3 .%采用二苯基甲烷二异氰酸酯和聚醚多元醇为原料反应制备A组分,聚醚多元醇、二胺扩链剂和耐磨助剂等混合制备B组分;A、B组分通过专用喷涂设备制备了聚氨酯弹性体耐磨涂层。讨论了聚醚多元醇和耐磨助剂的种类对弹性体涂层耐磨性能的影响,以及实验室干态下Akron磨耗、DIN磨耗、Taber磨耗和NBS磨耗4种磨耗之间的关系。结果表明,增滑助剂A的应用显著降低了喷涂型聚氨酯弹性体涂层的表面摩擦系数,测得动摩擦系数为0�321;聚四氢呋喃醚二醇的应用显著提高了喷涂型聚氨酯弹性体涂层的耐磨性能,测得Akron磨耗为0�030 cm3。

  13. Wear resistance of a Cr3C2-NiCr detonation spray coating

    Science.gov (United States)

    Wang, Jun; Wang, Jun; Sun, Baode; Guo, Qixin; Nishio, Mitsuhiro; Ogawa, Hiroshi

    2002-06-01

    Coatings can be applied to surfaces to improve the surface characteristics over those of the bulk properties and are widely used in tribological applications either to reduce wear and/or to modify friction during contact. One of the foremost coating methods for combating wear is thermal spraying. To prolong the life of steel slab continuous casting rolls, Cr3C2-NiCr detonation spray coating was processed on the roll surface in a steelmaking plant in China. This article studies the mechanical properties and wear resistance of this coating. The abrasive and dry frictional wear testing were performed using a pin-on-disk tester. Experimental results show that the wear resistance of the coated samples, i.e., coating reduces the risk of seizure compared to uncoated samples, is much better than those of the uncoated steel at room and elevated temperatures with any load and sliding velocity. The coating wear mechanisms under different test conditions are discussed.

  14. Maintenance and Preservation of Concrete Structures. Report 3. Abrasion-Erosion Resistance of Concrete.

    Science.gov (United States)

    1980-07-01

    the length of service that may be expected from a specific concrete. It can be used to determine the relative resistance of a material to the abrasive... CONTRAT 5) ATA CMNTFC IIICU 385 I E.p....s e - F.u 5 IA# RIEIE5, ROOF? *Fpa*RSt ftaE A, --EtI PA.. ,.md II, CRD-C 9. ANA .REdF. IA.. ... 1.(2,. TIB...intended to provide a quantitative measurement of the length of service that may be expected from a specific concrete. Note: Other test methods for

  15. Studies on the Structure and Properties of Multiphase Al2O3 Abrasion-resistant Ceramics

    Institute of Scientific and Technical Information of China (English)

    WU Ren-Ping; YU Yan; RUAN Yu-Zhong

    2006-01-01

    The Al2O3 abrasion-resistant ceramics is successfully prepared by using waste aluminum sludge as the main raw material with the addition of a little clay, talc and barium carbonate. The crystal structure and microstructure of ceramic are characterized by means of XRD,SEM, etc., and the physical and mechanical properties are also tested. The results show that besides the phase of corundum, a little mullite, Mg-Al spinel and hyalophane phases also exist in the product. These phases are produced via reaction in-situ, which can inhibit the overgrowth of Al2O3grain in grain boundary, and improve the integral property of the material.

  16. Influence of Utilization of High-Volumes of Class F Fly Ash on the Abrasion Resistance of Concrete

    Directory of Open Access Journals (Sweden)

    William PRINCE

    2007-01-01

    Full Text Available Utilization of large volumes of fly ash in various concrete applications is a becoming a more general practice in an efforts towards using large quantities of fly ash. Around the world, Class C or Class F or both as available have been used in high volumes in cement-based materials. In India, majority of fly generated is of Class F type as per ASTM C 618. Yearly fly ash generation in India is approximately 95 million tonnes. Out of which around 15-20% is utilized in cement production and cement/concrete related activities. In order to increase its percentage utilization, an investigation was carried out to use it in concrete.In this paper, abrasion resistance of high volume fly ash (HVFA concretes made with 35, 45, 55, and 65% of cement replacement was evaluated in terms of its relation with compressive strength. Comparison was made between ordinary Portland cement and fly ash concrete. Test results indicated that abrasion resistance of concrete having cement replacement up to 35 percent was comparable to the normal concrete mix with out fly ash. Beyond 35% cement replacement, fly ash concretes exhibited slightly lower resistance to abrasion relative to non-fly ash concretes. Test results further indicated that abrasion resistance of concrete is closely related with compressive strength, and had a very good correlation between abrasion resistance and compressive strength (R2 value between 0.9018 and 0.9859 depending upon age.

  17. Effect of Fe2B boride orientation on abrasion wear resistance of Fe-B cast alloy

    Directory of Open Access Journals (Sweden)

    Da-wei Yi

    2017-07-01

    Full Text Available The microstructures and abrasion wear resistance of directional solidification Fe-B alloy have been investigated using optical microscopy, X-ray diffraction, scanning electron microscopy and laser scanning microscopy. The results show that the microstructure of as-cast Fe-B alloy consists of ferrite, pearlite and eutectic boride. After heat treatment, the microstructure is composed of boride and martensite. The plane which is perpendicular to the boride growth direction possesses the highest hardness. In two-body abrasive wear tests, the silicon carbide abrasive can cut the boride and martensite matrix synchronously, and the wear mechanism is micro cutting mechanism. The worn surface roughness and the wear weight loss both increase with the increasing contact load. Moreover, when the boride growth direction is perpendicular to the worn surface, the highest hardness plane of the boride can effectively oppose abrasion, and the martensite matrix can surround and support borides perfectly.

  18. Effect of Heat Treatment of Wild Cherry Wood on Abrasion Resistance and Withdrawal Capacity of Screws

    Directory of Open Access Journals (Sweden)

    Ayhan Aytin

    2016-01-01

    Full Text Available In its wise use, many properties of wood are important. Among these properties, wood abrasion resistance (AR and withdrawal capacity of screws (WCS are deemed to be relatively signifi cant. It is well know that heat treatment changes the resistance features of wooden materials by changing the structural characteristics of wood. Within the scope of this study, the effects were investigated of the temperature and duration of heat treatment of Wild Cherry (Cerasus avium (L. Monench on its AR and its WCS in the radial direction and tangential direction. The test results indicated that weight loss (WL and thickness reduction (TR remained almost the same in the radial direction specimen, but there was significant TR in the tangential direction specimen. As a result of these changes, the abrasion effect of the S-42 abrader diminished based on the increase in the number of cycles. However, in both the radial and tangential direction, the WCS decreased to a significantly greater extent in the heat-treated specimens than in the control specimens.

  19. Wear resistance of TiAlSiN thin coatings.

    Science.gov (United States)

    Silva, F J G; Martinho, R P; Alexandre, R J D; Baptista, A P M

    2012-12-01

    In the last decades TiAIN coatings deposited by PVD techniques have been extensively investigated but, nowadays, their potential development for tribological applications is relatively low. However, new coatings are emerging based on them, trying to improve wear behavior. TiAlSiN thin coatings are now investigated, analyzing if Si introduction increases the wear resistance of PVD films. Attending to the application, several wear test configurations has been recently used by some researchers. In this work, TiAISiN thin coatings were produced by PVD Unbalanced Magnetron Sputtering technique and they were conveniently characterized using Scanning Electron Microscopy (SEM) provided with Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), Electron Probe Micro-Analyzer (EPMA), Micro Hardness (MH) and Scratch Test Analysis. Properties as morphology, thickness, roughness, chemical composition and structure, hardness and film adhesion to the substrate were investigated. Concerning to wear characterization, two very different ways were chosen: micro-abrasion with ball-on-flat configuration and industrial non-standardized tests based on samples inserted in a feed channel of a selected plastic injection mould working with 30% (wt.) glass fiber reinforced polypropylene. TiAISiN coatings with a small amount of about 5% (wt.) Si showed a similar wear behavior when compared with TiAIN reported performances, denoting that Si addition does not improve the wear performance of the TiAIN coatings in these wear test conditions.

  20. Tribological tests of wear-resistant coatings used in the production of drill bits of horizontal and inclined drilling

    Science.gov (United States)

    Maslov, A. L.; Markova, I. Yu; Zakharova, E. S.; Polushin, N. I.; Laptev, A. I.

    2017-05-01

    It is known that modern drilling bit body undergoes significant abrasive wear in the contact area with the solid and the retracted cuttings. For protection of the body rationally use wear-resistant coating, which is welded directly to the body of bit. Before mass use of the developed coverings they need to be investigated by various methods that it was possible to characterize coatings and on the basis of the obtained data to perform optimization of both composition of coatings and technology. Such methods include microstructural studies tribological tests, crack resistance and others. This work is devoted to the tribological tests of imported brand of coatings WokaDur NiA and and domestic brand of coating HR-6750 (both brands manufactured by Ltd “Oerlikon Metco Rus”), used to protect the bit body from abrasive wear.

  1. A new high temperature resistant glass–ceramic coating for gas turbine engine components

    Indian Academy of Sciences (India)

    Someswar Datta; Sumana Das

    2005-12-01

    A new high temperature and abrasion resistant glass–ceramic coating system (based on MgO–Al2O3–TiO2 and ZnO–Al2O3–SiO2 based glass systems) for gas turbine engine components has been developed. Thermal shock resistance, adherence at 90°-bend test and static oxidation resistance at the required working temperature (1000°C) for continuous service and abrasion resistance are evaluated using suitable standard methods. The coating materials and the resultant coatings are characterized using differential thermal analysis, differential thermogravimetric analysis, X-ray diffraction analysis, optical microscopy and scanning electron microscopy. The properties evaluated clearly showed the suitability of these coatings for protection of different hot zone components in different types of engines. XRD analysis of the coating materials and the resultant coatings showed presence of a number of microcrystalline phases. SEM micrographs indicate strong chemical bonding at the metal–ceramic interface. Optical micrographs showed smooth glossy impervious defect free surface finish.

  2. Abrasion and fatigue resistance of PDMS containing multiblock polyurethanes after accelerated water exposure at elevated temperature.

    Science.gov (United States)

    Chaffin, Kimberly A; Wilson, Charles L; Himes, Adam K; Dawson, James W; Haddad, Tarek D; Buckalew, Adam J; Miller, Jennifer P; Untereker, Darrel F; Simha, Narendra K

    2013-11-01

    Segmented polyurethane multiblock polymers containing polydimethylsiloxane and polyether soft segments form tough and easily processed thermoplastic elastomers (PDMS-urethanes). Two commercially available examples, PurSil 35 (denoted as P35) and Elast-Eon E2A (denoted as E2A), were evaluated for abrasion and fatigue resistance after immersion in 85 °C buffered water for up to 80 weeks. We previously reported that water exposure in these experiments resulted in a molar mass reduction, where the kinetics of the hydrolysis reaction is supported by a straight forward Arrhenius analysis over a range of accelerated temperatures (37-85 °C). We also showed that the ultimate tensile properties of P35 and E2A were significantly compromised when the molar mass was reduced. Here, we show that the reduction in molar mass also correlated with a reduction in both the abrasion and fatigue resistance. The instantaneous wear rate of both P35 and E2A, when exposed to the reciprocating motion of an ethylene tetrafluoroethylene (ETFE) jacketed cable, increased with the inverse of the number averaged molar mass (1/Mn). Both materials showed a change in the wear surface when the number-averaged molar mass was reduced to ≈ 16 kg/mole, where a smooth wear surface transitioned to a 'spalling-like' pattern, leaving the wear surface with ≈ 0.3 mm cracks that propagated beyond the contact surface. The fatigue crack growth rate for P35 and E2A also increased in proportion to 1/Mn, after the molar mass was reduced below a critical value of ≈30 kg/mole. Interestingly, this critical molar mass coincided with that at which the single cycle stress-strain response changed from strain hardening to strain softening. The changes in both abrasion and fatigue resistance, key predictors for long term reliability of cardiac leads, after exposure of this class of PDMS-urethanes to water suggests that these materials are susceptible to mechanical compromise in vivo.

  3. Characterization of the wear resistant aluminum oxide - 40% titaniumdioxide coating

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2014-02-01

    Full Text Available Plasma spray coatings play an important role in the design of surface properties of engineering components in order to increase their durability and performance under different operating conditions. Coatings are the most often used for wear resistance. This paper presents the microstructure and mechanical properties Al2O3_­40wt.%TiO2 coating resistant to dry friction slide, grain abrasion and erosion of particles at operating temperatures up to 540°C. In order to obtain the optimal characteristics of coating was performed  optimization  of deposition parameters. The powder Al2O3­40wt.%TiO2 is deposited atmospheric plasma spraying (APS process with a plasma current of 700, 800 and 900A. Evaluate the quality of the coating Al2O3­40wt.%TiO2 were made on the basis of their hardness, tensile bond strength and microstructure. The best performance showed the deposited layers with 900A. The morphology of the powder particles Al2O3­40wt.%TiO2 was examined with SEM (Scanning Electron Microscope. Microstructure of the coatings was examined by light microscopy. Analysis of the deposited layers was performed in accordance with standard Pratt & Whitney. Evaluation of mechanical properties of the layers was done by examining HV0.3 microhardness and tensile strength of the tensile testing. Studies have shown that plasma currents significantly affects the mechanical properties and microstructure of coatings which are of crucial importance for the protection for components subjected to wear       

  4. The role of the microfissuration of the rock matrix in the abrasion resistance of ornamental granitic rocks

    Science.gov (United States)

    Rodríguez-Rey, Angel; Sanchez-Delgado, Nuria; Camino, Clara; Calleja, Lope; Ruiz de Argandoña, Vicente G.; Setien, Alexia

    2015-04-01

    The microcrack density and the abrasion resistance of five ornamental granites (Albero, Gris Alba, Mondariz, Rosa Porriño and Traspieles) from Galicia (NW Spain) have been quantified as part of a research aimed to interpret the cuttability of the rocks in relation to the petrophysical properties of the rock matrix. Large blocks from the quarries have been cut with an industrial saw and the microcrack density and the abrasion resistance have been measured in two surfaces: H, parallel to the cut surface; T, perpendicular both to the cut surface and the cutting direction. Both planes are perpendicular to the rift plane, as it is known in quarry works. The microcrack density has been quantified following an stereological procedure applied to polished sections imaged under scanning electron microscopy. The magnification of the images allowed the study of microcracks as narrow as 2 microns in aperture. The density has been quantified in terms of length of microcrack traces per surface unit so possible anisotropies of the microcrack network could be detected. The obtained values are in the typical range for this type of rocks although the Traspieles granite shows a higher value due to its weathering degree (H: 5.11, T: 5.37 mm/mm2). The values measured in the two surfaces (H and T) are quite similar in four of the rocks; only the Albero granite shows a marked anisotropy (H: 2.76 T: 3.53 mm/mm2). The abrasion resistance of the rocks has been measured following the european standard EN 14157:2004 using the capon method. The rocks can be classified in two groups according to their abrasion resistance. Rosa Porriño, Gris Alba and Mondariz granites are the more resistant to abrasion with values around 16-17 mm. Albero and Traspieles granites are less resistant with values higher than 19 mm. The results show a good correlation between the microcrack density and the abrasion resistance. As can be expected the rocks with high microcrack density show low abrasion resistance. The

  5. Deposition of TiC film on titanium for abrasion resistant implant material by ion-enhanced triode plasma CVD

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Yuhe, E-mail: zyh1120@hotmail.co.jp [School of Stomatology, China Medical University, Shen Yang (China); Wang Wei; Jia Xingya [School of Stomatology, China Medical University, Shen Yang (China); Akasaka, Tsukasa [Department of Health Science, School of Dental Medicine Hokkaido University, Sapporo (Japan); Liao, Susan [School of Materials Science and Engineering, Nanyang Technological University (Singapore); Watari, Fumio [Department of Health Science, School of Dental Medicine Hokkaido University, Sapporo (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Deposition of Titanium Carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method. Black-Right-Pointing-Pointer The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance. Black-Right-Pointing-Pointer Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. - Abstract: Deposition of titanium carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method using a TiCl{sub 4} + CH{sub 4} + H{sub 2} gas mixture. Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. X-ray diffraction (XRD) showed that the specimen was consisted of TiC and Ti. Carbide layer of about 6 {mu}m thickness was observed on the cross section of the specimen by scanning electron microscopy (SEM). The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance.

  6. Microstructure and abrasive wear studies of laser clad Al-Si/SiC composite coatings

    NARCIS (Netherlands)

    Anandkumar, R.; Colaco, R.; Ocelik, V.; De Hosson, J. Th. M.; Vilar, R.; Gyulai, J; Szabo, PJ

    2007-01-01

    Surface coatings of Al-Si/SiC metal-matrix composites were deposited on Al-7 wt. % Si alloy substrates by laser cladding. The microstructure of the coatings was characterized by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microstructure of the coating mate

  7. Impact of Sn/F Pre-Treatments on the Durability of Protective Coatings against Dentine Erosion/Abrasion.

    Directory of Open Access Journals (Sweden)

    Carolina Ganss

    Full Text Available For preventing erosive wear in dentine, coating with adhesives has been suggested as an alternative to fluoridation. However, clinical studies have revealed limited efficacy. As there is first evidence that Sn(2+ increases bond strength of the adhesive Clearfil SE (Kuraray, the aim of the present study was to investigate whether pre-treatment with different Sn(2+/F(- solutions improves the durability of Clearfil SE coatings. Dentine samples (eight groups, n=16/group were freed of smear layer (0.5% citric acid, 10 s, treated (15 s either with no solution (control, aminefluoride (AmF, 500 ppm F(-, pH 4.5, SnCl2 (800/1600 ppm Sn(2+; pH 1.5, SnCl2/AmF (500 ppm F(-, 800 ppm Sn(2+, pH 1.5/3.0/4.5, or Elmex Erosion Protection Rinse (EP, 500 ppm F-, 800 ppm Sn(2+, pH 4.5; GABA International, then rinsed with water (15 s and individually covered with Clearfil SE. Subsequently the specimens were subjected to an erosion/abrasion protocol consisting of 1320 cycles of immersion in 0.5% citric acid (5 °C/55 °C; 2 min and automated brushing (15 s, 200 g, NaF-toothpaste, RDA 80. As the coatings proved stable up to 1320 cycles, 60 modified cycles (brushing time 30 min/cycle were added. Wear was measured profilometrically. After SnCl2/AmF, pH 4.5 or EP pre-treatment all except one coating survived. In the other groups, almost all coatings were lost and there was no significant difference to the control group. Pre-treatment with a Sn(2+/F(- solution at pH 4.5 seems able to improve the durability of adhesive coatings, rendering these an attractive option in preventing erosive wear in dentine.

  8. Effects of mechanical cleaning by manual brushing and abrasive blasting on lime render coatings on Architectural Heritage

    Directory of Open Access Journals (Sweden)

    Iglesias-Campos, M. A.

    2014-12-01

    Full Text Available This research studies the effects of mechanical cleaning by brushing and by abrasive blasting on the lime render coating of a façade. After analysing the properties of the material, the deposits to be removed and their possible influence on the treatment, different cleaning tests were made by manual brushing and by blasting with three varieties of abrasives at 45° and 75° angles, keeping the other parameters constant. Taking the restorer’s perspective as a starting point, and in order to fulfil the practical requirements of an intervention, tests were evaluated with macro-photography, USB digital microscope and stereomicroscope with 3D visualization and measurement. From the results can be concluded that abrasives with low friability and greater grain size than the space between mortar aggregates blasted at a 75° angle reduce the differential erosion compared to other abrasives; although manual brushing has less impact on the surface.En este trabajo se estudian los efectos de las limpiezas mecánicas con cepillado y con proyección de abrasivos sobre un revestimiento exterior de cal. Tras documentar las propiedades del material, de los depósitos superficiales y de su posible influencia en el tratamiento, se realizaron diferentes catas de limpieza con cepillado manual y con proyección de tres abrasivos con ángulos de 45° y 75° manteniendo constantes el resto de parámetros. Partiendo de la visión del conservador-restaurador y de un carácter práctico según las necesidades reales de intervención, los ensayos se evaluaron con macrofotografía, microscopio digital USB y microscopio estereoscópico con visualización y medición en 3D. De los resultados se determina que los abrasivos de baja friabilidad y granulometría mayor que el espacio entre los áridos del mortero proyectados con un ángulo de 75° reducen la erosión diferencial en comparación a otros abrasivos, aunque el cepillado manual altera menos la superficie.

  9. Self-Organization of Friction Surface of Fe-Mn-C-B Coating With Increased Resistance to Abrasion / Samoorganizacja Powierzchni Tarcia Powłoki Fe-Mn-C-B O Zwiększonej Odporności Na Zużycie Ścierne

    Directory of Open Access Journals (Sweden)

    Barszcz M.

    2015-12-01

    Full Text Available The paper concerns the research on self-organization of the surface of coating of hypoeutectic alloy Fe-Mn-C-B modified Si, Ni, Cr, Cu with friction with C45 steel. The coatings were obtained by arc welding using a flux-cored wire. Tests of resistance to wear were carried out for hypoeutectic coatings with use of the friction pair pin-on-disc in the conditions of sliding friction, in model lubricating environments. The surface-active (glycerol oil and inactive (Vaseline grease lubricant was used. Tribological tests carried out showed that cooperation of hypoeutectic alloy coating with counterbody of C45 steel with lubrication with surface-active lubricant results in a significant improvement in tribological properties than in case of the lubrication with surface-inactive lubricant. The resulting effect is related to the self-organization of friction surface. After deposition and wear resistance tests, the friction surface microstructure was analysed, as well as the surface and depth distribution of the elements.

  10. Hydro-abrasive erosion on coated Pelton runners: Partial calibration of the IEC model based on measurements in HPP Fieschertal

    Science.gov (United States)

    Felix, D.; Abgottspon, A.; Albayrak, I.; Boes, R. M.

    2016-11-01

    At medium- and high-head hydropower plants (HPPs) on sediment-laden rivers, hydro-abrasive erosion on hydraulic turbines is a major economic issue. For optimization of such HPPs, there is an interest in equations to predict erosion depths. Such a semi-empirical equation suitable for engineering practice is proposed in the relevant guideline of the International Electrotechnical Commission (IEC 62364). However, for Pelton turbines no numerical values of the model's calibration parameters have been available yet. In the scope of a research project at the high-head HPP Fieschertal, Switzerland, the particle load and the erosion on the buckets of two hard-coated 32 MW-Pelton runners have been measured since 2012. Based on three years of field data, the numerical values of a group of calibration parameters of the IEC erosion model were determined for five application cases: (i) reduction of splitter height, (ii) increase of splitter width and (iii) increase of cut-out depth due to erosion of mainly base material, as well as erosion of coating on (iv) the splitter crests and (v) inside the buckets. Further laboratory and field investigations are recommended to quantify the effects of individual parameters as well as to improve, generalize and validate erosion models for uncoated and coated Pelton turbines.

  11. Effect of flame conditions on abrasive wear performance of HVOF sprayed nanostructured WC-12Co coatings

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-yue; LI Chang-jiu; MA Jian; YANG Guan-jun

    2004-01-01

    Nanostructured WC-12Co coatings were deposited by high velocity oxy-fuel (HVOF) spraying with an agglomerated powder. The effect of flame conditions on the microstructure of the nanostructured coatings was investigated. The wear properties of the coatings were characterized using a dry rubber-wheel wear test. The results show that the nanostructured WC-Co coatings consist of WC, W2C, W and an amorphous binder phase. The microstructure of the coating is significantly influenced by the ratio of oxygen flow to fuel flow. Under the lower ratio of oxygen/fuel flow, the nanostructured coating presents a relative dense microstructure and severe decarburization of WC phase occurs during spraying. With increasing ratio of oxygen/fuel flow, the bonding of WC particles in the coating becomes loose resulting from the original structure of feedstock and the decarburization of WC becomes less owing to limited heating to the powder. Both the decarburization of WC particles in spraying and the bonding among WC particles in the coatings affect the wear performance. The examination of the worn surfaces of the nanostructured coatings reveals that the dominant wear mechanisms would be spalling from the interface of WCCo splats when spray particles undergo a limited melting. While the melting state of the spray particles is improved,the dominant wear mechanisms become the plastic deformation and plowing of the matrix and spalling of WC particles from the matrix.

  12. Measurement of the Resistance of Treated Metal Foils to Scrubbing Abrasion Using a Modified Reciprocating Wear Test

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Sikka, Vinod K [ORNL

    2007-01-01

    A reciprocating wear test method has been developed to evaluate the resistance of metal foils to scrubbing abrasion. Development included the definition of a quantitative measure of the scrubbing resistance. In order to test the ability of the new method to differentiate between surface treatments, four versions of Type 316 stainless steel foils were tested: annealed (A-NT), cold-worked (C-NT), annealed plus a case-hardened (A-T), and cold-worked plus case-hardened (C-T). Measurements were made of their scrubbing resistance using commercial kitchen scrub pads as the counterface material. Results showed that the case-hardening process significantly increased the scrubbing resistance both under dry conditions and with cleaning solutions to lubricate the contact. While this linearly-reciprocating method does not simulate the circular, overlapping motion commonly occurring in service, results indicated that the new test method could sufficiently discriminate levels of two-body abrasion behavior, and therefore can be useful for studying the effects of surface treatments on abrasion resistance.

  13. Improvement of abrasion resistance in artificial seawater and corrosion resistance in NaCl solution of 7075 aluminum alloy processed by laser shock peening

    Science.gov (United States)

    Wang, Hao; Ning, Chengyi; Huang, Yihui; Cao, Zhenya; Chen, Xiaoxiao; Zhang, Wenwu

    2017-03-01

    As 7075 aluminum alloy is widely used in a humid environment, in order to enhance its abrasion resistance and electrochemical corrosion resistance, the paper studied the effect of laser shock peening on abrasion resistance in artificial seawater and corrosion resistance in 3.5% NaCl solution of 7075 aluminum alloy. Result shows that when specimens were treated once and twice with 7.17 GW/cm2 the abrasion loss would be reduced by 43.75% and 46.09% compare to untreated respectively, and the corrosion rate of 7075 aluminum alloy could be reduced as much as 50.32% by LSP treatment with 7.17 GW/cm2. What's more, the effects on the microhardness, microstructure and residual stress with different LSP impacts and power density were investigated to find out strengthening mechanism of laser shock peening, which were observed and measured by microhardness tester, optical microscope and X-ray diffraction (XRD) residual stress tester. In the entire laboratory tests, it is considered that LSP is a practical option to improve abrasion resistance in seawater and corrosion resistance of 7075 aluminum alloy.

  14. Laser cladding of Al-Si/SiC composite coatings : Microstructure and abrasive wear behavior

    NARCIS (Netherlands)

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

    2007-01-01

    Surface coatings of an Al-Si-SiC composite were produced on UNS A03560 cast Al-alloy substrates by laser cladding using a mixture of powders of Al-12 wt.% Si alloy and SiC. The microstructure of the coatings depends considerably on the processing parameters. For a specific energy of 26 MJ/m2 the

  15. Laser cladding of Al-Si/SiC composite coatings : Microstructure and abrasive wear behavior

    NARCIS (Netherlands)

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

    2007-01-01

    Surface coatings of an Al-Si-SiC composite were produced on UNS A03560 cast Al-alloy substrates by laser cladding using a mixture of powders of Al-12 wt.% Si alloy and SiC. The microstructure of the coatings depends considerably on the processing parameters. For a specific energy of 26 MJ/m2 the mic

  16. Acid-resistant organic coatings for the chemical industry: a review

    DEFF Research Database (Denmark)

    Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria Grundahl

    2017-01-01

    Industries that work with acidic chemicals in their processes need to make choices on how to properly contain the substances and avoid rapid corrosion of equipment. Certain organic coatings and linings can be used in such environments, either to protect vulnerable construction materials, or......, in combination with fiber reinforcement, to replace them. However, degradation mechanisms of organic coatings in acid service are not thoroughly understood and relevant quantitative investigations are scarce. This review describes the uses and limitations of acid-resistant coatings in the chemical industry...... knowledge on chemical and physical degradation mechanisms is required, and that improvements in resistance to elevated temperatures and abrasion would decrease the risk of use and increase the potential application areas of organic coatings exposed to acidic environments in the chemical industry....

  17. Corrosion and Wear Resistance Characterization of Environmentally Friendly Sol-gel Hybrid Nanocomposite Coating on AA5083

    Institute of Scientific and Technical Information of China (English)

    Hamed Rahimi; Reza Mozaffarinia; Akbar Hojjati Najafabadi

    2013-01-01

    Environmentally friendly organic-inorganic hybrid nanocomposite films have been developed by sol-gel method for corrosion protection of AA5083 alloy.The hybrid nanocomposite coatings have been synthesized from tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) precursors.The multilayer coatings were prepared by dip-coating technique.Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was carried out to show the formation of the Si-O-Si structural backbone of the hybrid coatings.Structure and surface morphology of the coatings were studied by optical microscopy (OM),scanning electron microscopy (SEM) and atomic force microscopy (AFM).Characterization of the coatings with respect to pencil scratch hardness,adhesive and abrasion resistance was performed.The corrosion protection performance of these coatings was examined by using cyclic potentiodynamic polarization technique in Persian Gulf water.The results revealed that crack-free films with smooth surface were obtained.With increasing the number of sol-gel coated layers,corrosion resistance increased from 81 to 419 kΩ cm2,while the abrasion wear resistance did not change significantly.However,the triple sol-gel coated layer offered excellent protection against corrosion.

  18. Development of a new wear resistant coating by arc spraying of a steel-based cored wire

    Institute of Scientific and Technical Information of China (English)

    Lidong ZHAO; Binyou FU; Dingyong HE; Pia KUTSCHMANN

    2009-01-01

    In the present study, a cored wire of 304 L stainless steel as sheath material and NiB and WC-12Co as filler materials was designed and deposited to produce a new wear resistant coating containing amorphous phase by arc spraying. The microstructure of the coating was investigated. The porosity and hardness of the coating were determined. The wear performance of the coating was evaluated. The XRD and TEM analyses showed that there are high volume of amorphous phase and very fine crystalline grains in the coating. DTA measurements revealed that the crystallization of the amorphous phase occurred at 579.2℃. Because metallurgical processes for single droplets were non-homogenous during spraying, the lamellae in the coating have different hardness values, which lie between about 700 and 1250HV10og. The abrasive wear test showed that the new Fe-based coating was very wear resistant.

  19. Effect of Austenite Transformation on Abrasive Wear and Corrosion Resistance of Spheroidal Ni-Mn-Cu Cast Iron

    Directory of Open Access Journals (Sweden)

    Medyński D.

    2016-09-01

    Full Text Available Within the presented work, the effect of austenite transformation on abrasive wear as well as on rate and nature of corrosive destruction of spheroidal Ni-Mn-Cu cast iron was determined. Cast iron contained: 3.1÷3.4 %C, 2.1÷2.3 %Si, 2.3÷3.3 %Mn, 2.3÷2.5 %Cu and 4.8÷9.3 %Ni. At a higher degree of austenite transformation in the alloys with nickel equivalent below 16.0%, abrasive wear resistance was significantly higher. Examinations of the corrosion resistance were carried out with the use of gravimetric and potentiodynamic method. It was shown that higher degree of austenite transformation results in significantly higher abrasive wear resistance and slightly higher corrosion rate, as determined by the gravimetric method. However, results of potentiodynamic examinations showed creation of a smaller number of deep pinholes, which is a favourable phenomenon from the viewpoint of corrosion resistance.

  20. Co-blasting of titanium surfaces with an abrasive and hydroxyapatite to produce bioactive coatings: substrate and coating characterisation.

    Science.gov (United States)

    Dunne, Conor F; Twomey, Barry; O'Neill, Liam; Stanton, Kenneth T

    2014-01-01

    The aim of this work is to assess the influence of two blast media on the deposition of hydroxyapatite onto a titanium substrate using a novel ambient temperature coating technique named CoBlast. CoBlast was developed to address the problems with high temperature coating techniques. The blasting media used in this study were Al2O3 and a sintered apatite powder. The prepared and coated surfaces were compared to plasma sprayed hydroxyapatite on the same substrates using the same hydroxyapatite feedstock powder. X-ray diffraction analysis revealed the coating crystallinity was the same as the original hydroxyapatite feedstock powder for the CoBlast samples while evidence of amorphous hydroxyapatite phases and β-TCP was observed in the plasma sprayed samples. The blast media type significantly influences the adhesive strength of the coating, surface roughness of both the substrate and coating and the microstructure of the substrate. The coating adhesion increased for the CoBlasted samples from 50 MPa to 60 MPa for sintered apatite powder and alumina, respectively, while plasma spray samples were significantly lower (5 MPa) when tested using a modified pull-test. In conclusion, the choice of blast medium is shown to be a key parameter in the CoBlast process. This study indicates that sintered apatite powder is the most suitable candidate for use as a blast medium in the coating of medical devices.

  1. Effect of sodium bicarbonate air abrasive polishing on resistance to sliding during tooth alignment and leveling: An in vitro study

    Directory of Open Access Journals (Sweden)

    Jorge C. B. L. Filho

    2012-01-01

    Full Text Available Objective: The aim of this in vitro study was to evaluate the Resistance to Sliding (RS provided by metallic brackets and 3 types of orthodontic wires (TMA, SS and NiTi, before and after the use of sodium bicarbonate airborne particle abrasion, in an experimental model with 3 non leveled brackets. Materials and Methods: The bicarbonate airborne abrasion was applied perpendicularly to the bracket slots at a distance of 2 mm, for 5 seconds (T2 and 10 seconds (T3 on each bracket slot. In a universal testing machine, the wires were pulled through a set of 3 non leveled brackets at a cross head speed of 50 mm/min for a distance of 10 mm, and static and kinetic friction readings were registered at T1 (no airborne abrasion, T2 and T3. Results: For all tested wires, a significant RS increase between T1 and T3 (P<0.001 was seen. For SS and TMA wires, there was a statistically significant RS increase between T1 and T2 (P<0.001. Between T2 and T3, RS increase was significant for TMA (P<0.001 and NiTiwires (P<0.05. Conclusions: Sodium bicarbonate air abrasive polishing during orthodontic treatment is not recommended, once this procedure promoted a significant RS increase between the metallic brackets and all the three types of wires tested.

  2. Nanosecond laser micro- and nanotexturing for the design of a superhydrophobic coating robust against long-term contact with water, cavitation, and abrasion

    Science.gov (United States)

    Emelyanenko, Alexandre M.; Shagieva, Farida M.; Domantovsky, Alexandr G.; Boinovich, Ludmila B.

    2015-03-01

    Existing and emerging applications of laser-driven methods make an important contribution to advancement in nanotechnological approaches for the design of superhydrophobic surfaces. In this study, we describe a superhydrophobic coating on stainless steel, designed by nanosecond IR laser treatment with subsequent chemisorption of fluorooxysilane for use in heavily loaded hydraulic systems. Coating characterization reveals extreme water repellency, chemical stability on long-term contact with water, and excellent durability of functional properties under prolonged abrasive wear and cavitation loads. The coating also demonstrates self-healing properties after mechanical damage.

  3. Optically transparent superhydrophobic surfaces with enhanced mechanical abrasion resistance enabled by mesh structure.

    Science.gov (United States)

    Yokoi, Naoyuki; Manabe, Kengo; Tenjimbayashi, Mizuki; Shiratori, Seimei

    2015-03-04

    Inspired by naturally occurring superhydrophobic surfaces such as "lotus leaves", a number of approaches have been attempted to create specific surfaces having nano/microscale rough structures and a low surface free energy. Most importantly, much attention has been paid in recent years to the improvement of the durability of highly transparent superhydrophobic surfaces. In this report, superhydrophobic surfaces are fabricated using three steps. First, chemical and morphological changes are generated in the polyester mesh by alkaline treatment of NaOH. Second, alkaline treatment causes hydrophobic molecules of 1H,1H,2H,2H-perfluorodecyltrichlorosilane to react with the hydroxyl groups on the fiber surfaces forming covalent bonds by using the chemical vapor deposition method. Third, hydrophobicity is enhanced by treating the mesh with SiO2 nanoparticles modified with 1H,1H,2H,2H-perfluorooctyltriethoxysilane using a spray method. The transmittance of the fabricated superhydrophobic mesh is approximately 80% in the spectral range of 400-1000 nm. The water contact angle and the water sliding angle remain greater than 150° and lower than 25°, respectively, and the transmittance remains approximately 79% after 100 cycles of abrasion under approximately 10 kPa of pressure. The mesh surface exhibits a good resistance to acidic and basic solutions over a wide range of pH values (pH 2-14), and the surface can also be used as an oil/water separation material because of its mesh structure.

  4. Effect of Silicon on M7C3 Phases and Abrasion Resistance of Open Arc Hardfacing Alloys

    Directory of Open Access Journals (Sweden)

    TIAN Bing

    2017-04-01

    Full Text Available Fe-17Cr-4C-2V-Mn-Si-Ti complex system hardfacing alloys were deposited by using flux-cored wire self-shielded open arc welding. The effects of silicon on their M7C3 ( M =Fe, Cr, V, Mn phases and abrasion resistance were investigated by OM, XRD and SEM. The results show that, with silicon content increasing from 0.6%(mass fraction to 2.4%, the size of primary M7C3carbides gradually reduces and transites from rod-like shape to block-like shape in dispersion distributing state. γ-Fe phases, which adjacent to those primary M7C3 grains, progressively reduce until disappear. It dues to that silicon can change the precursor of primary M7C3 nucleates in nature, e.g. liquid high carbon atom clusters and it results in the change of their morphology, distribution and size. The wear test results indicate that the abrasion resistance of open arc hardfacing alloys improves firstly and then reduces when silicon content increases from 0.6% to 2.4%. The optimum abrasion resistance is acquired at 1.5%Si. The analysis on the surface worn morphologies show that the micro-cutting and micro-spalling wearing mechanisms coexist.

  5. The structure, properties and a resistance to abrasive wear of railway sections of steel with a different pearlite morphology

    Energy Technology Data Exchange (ETDEWEB)

    Aniolek, K [Institute of Materials Science, University of Silesia, Bankowa 12, 40-007 Katowice (Poland); Herian, J, E-mail: jerzy.herian@polsl.pl [Department of Materials Technology, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

    2011-05-15

    The article presents the characteristics of pearlite rail steels used in the construction of railways. The article discusses the influence of isothermal annealing process parameters on the pearlite morphology and properties of the R260 steel. The pearlite structure with a diverse pearlite morphology was obtained in the physical modeling of the isothermal annealing on the 3800 Gleeble Simulator. After the heat treatment, the existence of the pearlite microstructure with pearlite colonies was identified. They were smaller in relation to colonies after the hot rolling process. It was shown that the reduction of isothermal holding temperature influences the decrease of the interlamellar distance in the pearlite steel. On the basis of the received results, the dependences between the resistance to the abrasive wear and the pearlite morphology for operational conditions occurring in the switches were estimated. The resistance to the abrasive wear tests were conducted for steel with a different morphology of pearlite on the Amsler stand in conditions of rolling- sliding frictions. The resistance to the abrasive wear of R260 steel with a different pearlite morphology increases, when the interlamellar distance in cementite decreases and decreases as the load and slip increase.

  6. Improvement in Abrasion Wear Resistance and Microstructural Changes with Deep Cryogenic Treatment of Austempered Ductile Cast Iron (ADI)

    Science.gov (United States)

    Šolić, Sanja; Godec, Matjaž; Schauperl, Zdravko; Donik, Črtomir

    2016-10-01

    The application of a deep cryogenic treatment during the heat-treatment processes for different types of steels has demonstrated a significant influence on their mechanical and tribological properties. A great deal of research was conducted on steels, as well as on other kinds of materials, such as hard metal, gray cast iron, aluminum, aluminum alloys, etc., but not on austempered ductile iron (ADI). In this research the influence of a deep cryogenic treatment on the microstructure and abrasive wear resistance of austempered ductile iron was investigated. The ductile cast iron was austempered at the upper ausferritic temperature, deep cryogenically treated, and afterwards tempered at two different temperatures. The abrasion wear resistance was tested using the standard ASTM G65 method. The microstructure was characterized using optical microscopy, field-emission scanning electron microscopy, electron back-scattered diffraction, and X-ray diffraction in order to define the microstructural changes that influenced the properties of the ADI. The obtained results show that the deep cryogenic treatment, in combination with different tempering temperatures, affects the matrix microstructure of the austempered ductile iron, which leads to an increase in both the abrasion wear resistance and the hardness.

  7. Improving the Wear Resistance of Moulds for the Injection of Glass Fibre–Reinforced Plastics Using PVD Coatings: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Francisco Silva

    2017-02-01

    Full Text Available It is well known that injection of glass fibre–reinforced plastics (GFRP causes abrasive wear in moulds’ cavities and runners. Physical vapour deposition (PVD coatings are intensively used to improve the wear resistance of different tools, also being one of the most promising ways to increase the moulds’ lifespan, mainly when used with plastics strongly reinforced with glass fibres. This work compares four different thin, hard coatings obtained using the PVD magnetron sputtering process: TiAlN, TiAlSiN, CrN/TiAlCrSiN and CrN/CrCN/DLC. The first two are monolayer coatings while the last ones are nanostructured and consist of multilayer systems. In order to carry out the corresponding tribological characterization, two different approaches were selected: A laboratorial method, using micro-abrasion wear tests based on a ball-cratering configuration, and an industrial mode, analysing the wear resistance of the coated samples when inserted in a plastic injection mould. As expected, the wear phenomena are not equivalent and the results between micro-abrasion and industrial tests are not similar due to the different means used to promote the abrasion. The best wear resistance performance in the laboratorial wear tests was attained by the TiAlN monolayer coating while the best performance in the industrial wear tests was obtained by the CrN/TiAlCrSiN nanostructured multilayer coating.

  8. Methods of data analysis for the micro-scale abrasion test on coated substrates

    DEFF Research Database (Denmark)

    Kusano, Y.; Acker, K. Van; Hutchings, I.M.

    2004-01-01

    and the coating thickness. In general the errors in kappa(c) and kappa(s) are determined by the ratio of the specific wear rates kappa(c)/kappa(s), the non-dimensional parameter a(2)/Rt (where a is the inner crater diameter, R is the ball radius and t is the coating thickness), and the relative measurement errors...... of the inner crater diameter and the coating thickness. As these relative errors decrease, the errors in both kappa(c) and kappa(s) decrease. In addition a decrease in kappa(c)/kappa(s) and/or a(2) /Rt will decrease the error in K-c, but increase that in K-s. For a typical case where R= 12.5 mm, t= 3 +/- 0...... be measured more accurately than the outer crater diameter since it is more clearly defined. It is recommended to obtain an accurate value for coating thickness, e.g. by creating and measuring a sharply defined crater, and then to calculate the wear volumes in terms of the inner crater diameter...

  9. Study on abrasion resisting material for apron of dam; Dam apron bu no taimamo sozai ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, H.; Hiraki, M.; Miyamoto, T. [Hokuriku Electric Power Co. Inc., Toyama (Japan)

    1995-01-25

    A `laminated rubber tile` and a `shock absorbing holed-in anchor` were devised in connection with the apron of a dam for a hydroelectric power plant. As the result of a survey on the hydroelectric power plants, ten plus places were observed where a general kind of concrete was severely worn in the company territory; but, there were substantial number of rubber materials that had still been sound for over ten years after the installation. In spite of the soundness of the rubber tiles, however, it was observed that their anchor supports had been cut and separated. An abrasion comparison test of concrete and rubber materials revealed that the rubber materials were considerably superior in abrasion resistance. Various rubber tiles were tested for abrasion resistance, tear strength, tensile strength, impact strength, etc.; and methods for fixing rubber tiles were also tested such as a holed-in anchor, chemical anchor and adhesives. As a result, a laminated rubber tile was designed with its upper layer constituted of a rubber sold on the market and its lower layer of a fiber reinforced rubber also on the market, and so was a shock absorbing type holed-in anchor. 1 ref., 11 figs., 4 tabs.

  10. Effect of Heat Treatment on Wear Resistance of Nickel Aluminide Coatings Deposited by HVOF and PTA

    Science.gov (United States)

    Benegra, M.; Santana, A. L. B.; Maranho, O.; Pintaude, G.

    2015-08-01

    This study aims to compare the wear resistance of nickel aluminide coatings deposited using plasma transferred arc (PTA) and high-velocity oxygen fuel (HVOF) processes. Wear resistance was measured in rubber wheel abrasion tests. In both deposition processes, the same raw material (nickel aluminide powder) was atomized and deposited on a 316L steel plate substrate. After deposition, specimens were subjected to thermal cycling, aiming solubilization and precipitation. Coatings deposited using PTA developed different microstructures as a result of the incorporation of substrate elements. However, despite the presence of these microstructures, they performed better than coatings processed using HVOF before the heat treatment. After thermal cycling, the superficial hardness after the wear tests for both processes was similar, resulting in similar mass losses.

  11. Brush seal shaft wear resistant coatings

    Science.gov (United States)

    Howe, Harold

    1995-03-01

    Brush seals suffer from high wear, which reduces their effectiveness. This work sought to reduce brush seal wear by identifying and testing several industry standard coatings. One of the coatings was developed for this work. It was a co-sprayed PSZ with boron-nitride added for a high temperature dry lubricant. Other coatings tested were a PSZ, chrome carbide and a bare rotor. Testing of these coatings included thermal shocking, tensile testing and wear/coefficient of friction testing. Wear testing consisted of applying a coating to a rotor and then running a sample tuft of SiC ceramic fiber against the coating. Surface speeds at point of contact were slightly over 1000 ft/sec. Rotor wear was noted, as well as coefficient of friction data. Results from the testing indicates that the oxide ceramic coatings cannot withstand the given set of conditions. Carbide coatings will not work because of the need for a metallic binder, which oxidizes in the high heat produced by friction. All work indicated a need for a coating that has a lubricant contained within itself and the coating must be resistant to an oxidizing environment.

  12. A New Approach of Improving Rain Erosion Resistance of Nanocomposite Sol-Gel Coatings by Optimization Process Factors

    Science.gov (United States)

    Hojjati Najafabadi, Akbar; Shoja Razavi, Reza; Mozaffarinia, Reza; Rahimi, Hamed

    2014-05-01

    Erosion protection nanocomposite sol-gel coatings based on tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxisilane (GPTMS) are prepared and characterized to protect marine structures susceptible to damage caused by liquid impact, e.g., the submarine body. This study focuses on the optimization of compositional and process parameters of transparent hybrid nanocomposite sol-gel coatings resistant to rain erosion by using statistical design of experimental methodology (DoE) based on Taguchi orthogonal design. The impact of compositional and process parameters of the coatings on the erosion protection performance is investigated by five-factor-four-level design methodology. Hybrid coatings were deposited on AA5083 by a dip coating technique. Optimization coatings are analyzed regarding their adhesion (pull-off), flexibility (impact and mandrel bending), hardness (pencil), wear (Taber wear index), and rain erosion resistance (stationary sample erosion test). The surface morphology and roughness were studied by field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The optimization coatings showed excellent flexibility and adhesion to the substrate with smooth nanostructure surface; the RMS surface roughness was 1.85 nm. The evaluation of the result obtained from abrasion shows cohesive and interfacial wear with abrasive and adhesive mechanisms, respectively. Liquid impact results show cohesive failure of the coatings without any sign of delamination.

  13. Researches concerning the ultasonic energy influence on the resistence to the abrasive wear of loaded welded parts

    Directory of Open Access Journals (Sweden)

    Gh. Amza

    2013-01-01

    Full Text Available The researches presented in the paper refer to the effect of ultrasounds propagation in the liquid metal bath on the process of transferring the additive material through the electric arch and on the crystallization process, and all these effects are analyzed for loaded welded parts solicited at the abrasive wear. All these influences are conferred to these two basic phenomena due to the ultrasounds propagation in liquid environments, namely, ultra-acoustic cavitation and acceleration of the diffusion process. The results concerns the resistance to the wear obtained for the loaded parts through manual welding with electric arch and classically covered electrode and ultrasonically activated.

  14. Influence of secondary carbide precipitation and transformation on abrasion resistance of a 3Cr15Mo1V1.5 white iron

    Institute of Scientific and Technical Information of China (English)

    Haohuai Liu; Jun Wang; Baoluo Shen; Hongshan Yang; Shengji Gao; Sijiu Huang

    2007-01-01

    The relationship between the secondary carbide precipitation and transformation of the 3Cr15Mo1V1.5 white iron and abrasion resistance was investigated by using optical microscope (OM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that the properties of secondary carbides precipitated at holding stage play an important role in the abrasion resistance. After certain holding time at 833 K subcritical treatment, the grainy (Fe, Cr)23C6 carbide precipitated and the fresh martensite transformed at the holding stage for 3Cr15Mo1V1.5 white iron improve the bulk hardness and abrasion resistance of the alloy. Prolonging holding time, MoC and (Cr, V)2C precipitations cause the secondary hardening peak and the corresponding better abrasion resistance. Finally, granular (Fe, Cr)23C6 carbide in situ transforms into laminar M3C carbide and the matrix structure transforms into pearlitic matrix. These changes weaken hardness and abrasion resistance of the alloy sharply.

  15. Development of wear resistant nanostructured duplex coatings by high velocity oxy-fuel process for use in oil sands industry.

    Science.gov (United States)

    Saha, Gobinda C; Khan, Tahir I; Glenesk, Larry B

    2009-07-01

    Oil sands deposits in Northern Alberta, Canada represent a wealth of resources attracting huge capital investment and significant research focus in recent years. As of 2005, crude oil production from the current oil sands operators accounted for 50% of Canada's domestic production. Alberta's oil sands deposits contain approximately 1.7 trillion barrels of bitumen, of which over 175 billion are recoverable with current technology, and 315 billion barrels are ultimately recoverable with technological advances. A major problem of operating machinery and equipment in the oil sands is the unpredictable failure from operating in this highly aggressive environment. One of the significant causes of that problem is premature material wear. An approach to minimize this wear is the use of protective coatings and, in particular, a cermet thin coating. A high level of coating homogeneity is critical for components such as bucketwheels, draglines, conveyors, shovels, heavyhauler trucks etc. that are subjected to severe degradation through abrasive wear. The identification, development and application of optimum wear solutions for these components pose an ongoing challenge. Nanostructured cermet coatings have shown the best results of achieving the degree of homogeneity required for these applications. In this study, WC-17Co cermet powder with nanocrystalline WC core encapsulated with 'duplex' Co layer was used to obtain a nanostructured coating. To apply this coating, high velocity oxy-fuel (HVOF) thermal spraying technique was used, as it is known for producing wear-resistant coatings superior to those obtained from plasma-based techniques. Mechanical, sliding wear and microstructural behavior of the coating was compared with those of the microstructured coating obtained from spraying WC-10Co-4Cr cermet powder by HVOF technique. Results from the nanostructured coating, among others, showed an average of 25% increase in microhardness, 30% increase in sliding wear resistance and

  16. Effect of high-manganese cast steel strain hardening on the abrasion wear resistance in a mixture of SiC and water

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2013-12-01

    Full Text Available The study attempts to determine the impact of the high-manganese cast steel strain hardening on its abrasion wear resistance in a mixture of SiC and water prepared in accordance with ASTM G75. For tests, the high-manganese cast steel containing 10.7, 17.9 and 20.02% Mn was selected. The results of microstructure examinations and abrasion wear resistance tests carried out on the material in non-hardened condition and after strain hardening with a force of 539.55kN were disclosed. Additionally, the surface of samples after a 16-hour cycle of abrasion tests was examined. Moreover, based on the obtained results, the effect of different contents of Mn in cast steel was studied, mainly in terms of its impact on the abrasion wear resistance. The results obtained on the tested materials were compared with the results obtained on the low-alloyed abrasion wear-resistant cast steel L35GSM.

  17. Facile fabrication of superhydrophobic surface with excellent mechanical abrasion and corrosion resistance on copper substrate by a novel method.

    Science.gov (United States)

    Su, Fenghua; Yao, Kai

    2014-06-11

    A novel method for controllable fabrication of a superhydrophobic surface with a water contact angle of 162 ± 1° and a sliding angle of 3 ± 0.5° on copper substrate is reported in this Research Article. The facile and low-cost fabrication process is composed from the electrodeposition in traditional Watts bath and the heat-treatment in the presence of (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane (AC-FAS). The superhydrophobicity of the fabricated surface results from its pine-cone-like hierarchical micro-nanostructure and the assembly of low-surface-energy fluorinated components on it. The superhydrophobic surface exhibits high microhardness and excellent mechanical abrasion resistance because it maintains superhydrophobicity after mechanical abrasion against 800 grit SiC sandpaper for 1.0 m at the applied pressure of 4.80 kPa. Moreover, the superhydrophobic surface has good chemical stability in both acidic and alkaline environments. The potentiodynamic polarization and electrochemical impedance spectroscopy test shows that the as-prepared superhydrophobic surface has excellent corrosion resistance that can provide effective protection for the bare Cu substrate. In addition, the as-prepared superhydrophobic surface has self-cleaning ability. It is believed that the facile and low-cost method offer an effective strategy and promising industrial applications for fabricating superhydrophobic surfaces on various metallic materials.

  18. Effect of the CaF2-fraction in the glass-ceramic with abrasion resistance on crystallization

    Institute of Scientific and Technical Information of China (English)

    HU Bin-liang; Zhao Yun-cai

    2005-01-01

    Investigated the effect of an addition of CaF2 on the crystallization of a glass-ceramic with abrasion resistance. X-ray diffraction, differential thermal analysis and scanning electron microscopy were used to determine the effect. The results showed that a suitable addition of CaF2 promoted crystallization by forming an intermediate crystalline phase. CaF2 can decrease the temperature and active energy of the base-glass for crystallization. When 4 mass-% of CaF2-fraction is added in the glass, the crystallization temperature and active energy is 936℃and 172.75 k J/mol respectively.When CaF2 is increased to 6 mass-%, the temperature and active energy decrease to 890℃ and 88.81 kJ/mol. CaF2 is an efficient nucleating agent for the glass-ceramics with abrasion resistant, the optimal content of CaF2 is about 6 mass-%.

  19. Effect of ion nitriding on the abrasive wear resistance of ultrahigh-strength steels with different silicon contents

    Science.gov (United States)

    Riofano, R. M. Muñoz; Casteletti, L. C.; Nascente, P. A. P.

    2005-02-01

    This article studies the effect of silicon (Si) on ultrahigh-strength AISI 4340 steels in connection with the thermal treatment, as well as the influence of this element on nitriding and, consequently, abrasive wear. Four alloys with different Si contents were nitrided at 350 °C (4 and 8 h) and 500 and 550 °C (2 and 4 h) in a gas mixture of 80 vol.% H2 and 20 vol.% N2. The nitrided layers were characterized by microhardness and pin-on-disk tests, optical microscopy, scanning electron microscopy with energy-dispersive x-ray spectrometry, and x-ray diffraction (XRD). The increase in Si enhanced the tempering resistance of the steels and also improved considerably the hardness of the nitrided layers. The increase in Si produced thinner compound layers with better hardness quality and high abrasive wear resistance. XRD analysis detected a mixture of nitrides in the layers γ‧-Fe4N, ɛ-Fe2 3N, CrN, MoN, and Si3N4 with their proportions varying with the nitriding conditions.

  20. Analysis Of The Austenite Grain Growth In Low-Alloy Boron Steel With High Resistance To Abrasive Wear

    Directory of Open Access Journals (Sweden)

    Białobrzeska B.

    2015-09-01

    Full Text Available Today low-alloy steels with boron achieve high resistance to abrasive wear and high strength. These features are obtained by using advanced technology of manufacturing. This makes boron steels increasingly popular and their application more diverse. Application of these steels can extend the lifetime of very expensive machine construction in many industries such as mining, the automotive, and agriculture industries. An interesting subgroup of these materials is steel with boron intended for heat treatment. These steels are supplied by the manufacturer after cold or hot rolling so that it is possible for them to be heat treated in a suitable manner by the purchaser for its specific application. Very important factor that determines the mechanical properties of final product is austenite grain growth occurring during hot working process such us quenching or hot rolling. Investigation of the effect of heating temperature and holding time on the austenite grain size is necessary to understand the growth behavior under different conditions. This article presents the result of investigation of austenite grain growth in selected low-allow boron steel with high resistance to abrasive wear and attempts to describe the influence of chemical composition on this process.

  1. Application of laser scanning microscopy in the development of highly abrasion-resistant glazes for fast-fired hard paste porcelain

    Energy Technology Data Exchange (ETDEWEB)

    Pham-Gia, K.; Moertel, H. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Glas und Keramik; Melchner, R.; Voit, K. [Porzellanfabrik Christian Seltmann GmbH, Weiden (Germany)

    2001-08-01

    To strengthen the competitiveness of porcelain manufacturers in national and international markets with their ever increasing quality requirements, the research presented was aimed at developing highly abrasion-resistant glazes for fast-fired hard paste porcelain. By increasing the degree of cross-linking in the glass structure, it was possible to improve the mechanical abrasion resistance of porcelain glazes. Uniform and defect-free glaze application is particularly important for achieving this improvement. To determine the abrasion resistance of the glazes, a new testing method was developed in which the glaze surface is analysed topographically with a laser scanning microscope before and after defined sand-blasting and the roughness parameters compared. The glaze development work could be minimized with the help of fractional factorial statistical test planning according to the Taguchi method. (orig.)

  2. Preparation and Properties of Superamphiphobic Wear-resistance PPS-based Coating

    Directory of Open Access Journals (Sweden)

    WANG Huai-yuan

    2017-01-01

    Full Text Available Superamphiphobic wear-resistance PPS-based coatings were prepared by a simple spraying method with a pore-forming reagent of NH4HCO3 and nano-filler of carbon nanotubes (CNTs.The surface morphology and the hydrophobicity,oleophobicity of the coating were analyzed by scanning electron microscope (SEM and contact angle meter.The wear-resistance of the coating was verified by sanding method with given load.The results indicate that a rough surface is obtained after pore-forming,and the porous structures in combination with the CNTs construct the special micro/nano-scale network structures.When the mass fraction of NH4HCO3 is 5%,the contact angles of the coating for water,glycerine and ethylene glycol are 162°,158° and 152°,showing superamphiphobic property.After polished 10000 times by abrasive paper,the coating shows slight friction marks and remains high hydrophobicity,exhibiting excellent wear-resistance.

  3. Effects on Structure and Abrasion Resistance of GCr15 Steel by Surface Gas-Phase RE Diffused Permeation with Laser Melting Solidification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effects on abrasion resistance and the microstructure of GCr15 steel surface by the compound technology of permeating RE combined with laser melting modification was studied. The results show that after compound treatment, the abrasion resistance of samples has been improved significantly and the weight loss has been reduced to 14% of blank sample; the microstructure has been denser and more uniform than that of untreated; meanwhile, the grain has been refined and the concentration gradients of the elements permeated have been decreased obviously.

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

    Directory of Open Access Journals (Sweden)

    Eitvydas GRUZDYS

    2011-07-01

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

  5. Effects of increase extent of voltage on wear and corrosion resistance of micro-arc oxidation coatings on AZ91D alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of increase extent of voltage on the wear resistance and corrosion resistance of micro-arc oxidation(MAO)coatings on AZ91D magnesium alloy were investigated in silicate electrolyte.The results show that with increasing extent of voltage,both of the thickness and bonding force of MAO coatings first increase,and then decrease.These parameters are all up to their maximum values when the increase extent of voltage is 20 V.The roughness of the coatings always increases.The coating has the best corrosion resistance when the increase extent of voltage is not below 25 V,and the coating has the best wear resistance when the increase extent of voltage is 10 V.The wear mechanisms for the micro-arc oxidation are abrasive wear and micromachining wear.These are related to their microstructures.

  6. Thermal Barrier Coatings Resistant to Glassy Deposits

    Science.gov (United States)

    Drexler, Julie Marie

    Engineering of alloys has for years allowed aircraft turbine engines to become more efficient and operate at higher temperatures. As advancements in these alloy systems have become more difficult, ceramic thermal barrier coatings (TBCs), often yttria (7 wt %) stabilized zirconia (7YSZ), have been utilized for thermal protection. TBCs have allowed for higher engine operating temperatures and better fuel efficiency but have also created new engineering problems. Specifically, silica based particles such as sand and volcanic ash that enter the engine during operation form glassy deposits on the TBCs. These deposits can cause the current industrial 7YSZ thermal barrier coatings to fail since the glass formed penetrates and chemically interacts with the TBC. When this occurs, coating failure may occur due to a loss of strain tolerance, which can lead to fracture, and phase changes of the TBC material. There have been several approaches used to stop calcium-magnesium aluminio-silcate (CMAS) glasses (molten sand) from destroying the entire TBC, but overall there is still limited knowledge. In this thesis, 7YSZ and new TBC materials will be examined for thermochemical and thermomechanical performance in the presence of molten CMAS and volcanic ash. Two air plasma sprayed TBCs will be shown to be resistant to volcanic ash and CMAS. The first type of coating is a modified 7YSZ coating with 20 mol% Al2O3 and 5 mol% TiO2 in solid solution (YSZ+20Al+5Ti). The second TBC is made of gadolinium zirconate. These novel TBCs impede CMAS and ash penetration by interacting with the molten CMAS or ash and drastically changing the chemistry. The chemically modified CMAS or ash will crystallize into an apatite or anorthite phase, blocking the CMAS or ash from further destroying the coating. A presented mechanism study will show these coatings are effective due to the large amount of solute (Gd, Al) in the zirconia structure, which is the key to creating the crystalline apatite or

  7. Study on abrasion resistance of overlayment of self-leveling mortar%面层自流平砂浆的耐磨性能研究

    Institute of Scientific and Technical Information of China (English)

    戴浩; 刘艳; 王中兰; 李东旭

    2017-01-01

    研究了胶粉、酒石酸缓凝剂、胶凝材料、骨料级配和硬化剂对铝酸盐水泥基自流平砂浆耐磨性的影响,分析了砂浆耐磨性与流动度和强度的相关性.结果表明:胶粉可提高自流平砂浆的耐磨性,主要通过提高砂浆的稳定性和柔性来实现.酒石酸缓凝剂会增加砂浆的离析沉降程度,从而导致耐磨性降低.在以铝酸盐水泥为主的三元体系自流平砂浆中,适量增加石膏和硅酸盐水泥掺量均有利于提高耐磨性;降低胶凝材料用量,砂浆耐磨性降低.当40~70目砂和70~140目砂用量各为20%时,自流平砂浆的耐磨性最好.在自流平砂浆表面涂刷硬化剂,可提高表层的密实度和耐磨性,硬化剂涂刷量达到饱和用量,耐磨性提高不大.%The influence of latex powder,tartaric acid,cementitious materials,aggregate grading and curing agent on abrasion resistance of calcium aluminate cement-based self-leveling mortars (SLM) have been studied,and relativities between abrasion resistance and flow value,strength were analyzed as well. Results show that latex powder may enhance the wear resistance of SLM by improving its stability and flexibility. Tartaric acid may increase the mortars segregation settling extent,which will lead to decreasing of abrasion resistance. For calcium aluminate cement-based ternary system self-leveling mortars,increasing content of ordinary Portland cement and calcium sulfate moderately are propitious to wear resistance. Besides,the decreasing content of cementitious materials cause degradation of abrasion performance. Mortars with 20% 40~70 mesh sand and 20% 70~140 mesh sand present the superior abrasion resistance. By brushing curing agent,mortars surface exhibit a significant increasing in density and abrasion resistance. When curing agent reaches the saturation dosage,the improvement of abrasion resistance is not obvious.

  8. The Effect of Silane on the Microstructure, Corrosion, and Abrasion Resistances of the Anodic Films on Ti Alloy

    Science.gov (United States)

    Wang, Jinwei; Chen, Jiali

    2016-04-01

    Anodic oxide films on Ti-6Al-4V alloy are prepared using sodium hydroxide as the base electrolyte containing aminopropyl trimethoxysilane (APS) as an additive. Some APS undergo hydrolysis, adsorption, and chemical reaction with the TiO x to form Ti-O-Si bond as confirmed by ATR-FTIR and XPS spectra, and in turn their surface appearance and roughness are greatly changed with the addition of APS as observed by their SEM images. These amino anodic films possess much higher corrosive resistances since the formation of Ti-O-Si complex enhances the compactness of the anodic films and the existence of aminopropyl groups inside the pores provides additional blocking effects. Besides, their improvement in anti-abrasive capability is attributed to the toughening effect of the chemically bonded silanes and the lubrication functions from both the chemically bonded and physically absorbed silanes between the touched interfaces.

  9. Multi-layer coatings

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze' ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  10. Influence of Hardness, Matrix and Carbides in Combination with Nitridation on Abrasive Wear Resistance of X210Cr12 Tool Steel

    Directory of Open Access Journals (Sweden)

    Martin Orečný

    2016-10-01

    Full Text Available Materials used in abrasive wear conditions are usually selected according to their microstructure and hardness, however, other factors such as grain size, matrix saturation, carbides size and morphology are rarely considered. Therefore, the present study deals with the influence of different heat and chemical-heat treatments including their combination on abrasive wear resistance of X210Cr12 tool steel. The effects of material hardness, carbide morphology and microstructure on wear resistance after quenching and nitriding were also investigated. One sample series was quenched after austenitization at 960 °C for 20 min and tempered at 180 °C for 2 h. The second sample series was quenched from 1060 °C austenitization for 20 min and afterwards twice tempered at 530 °C for 1 h. From both the quenched and tempered states, one half of the samples was gas nitrided in NH3 atmosphere for 3 h and then diffusion annealed in N2 atmosphere for 4 h. Abrasion wear tests were performed by sliding the samples on Al2O3 paper. The samples weight loss was considered the main criterion for the wear resistance evaluation. The microstructures, nitrided layers and worn surfaces were observed using SEM microscopy. The highest abrasion wear resistance was obtained for the nitrided samples that were previously quenched from 1060 °C and tempered at 530 °C.

  11. Empirical ranking of a wide range of WC-Co grades in terms of their abrasion resistance measured by the ASTM standard B 611-85 test

    CSIR Research Space (South Africa)

    O'Quigley, DGF

    1997-01-01

    Full Text Available This paper reports the results of a comprehensive investigation into the abrasion resistance of WC-Co alloys, as measured by the ASTM Standard B 611-85 test. The alloys ranged from 3 to 50 wt% and from 0.6 to 5 mu-m average grain size. Careful...

  12. The structure of abrasion-resisting castings made of chromium cast iron

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2011-01-01

    Full Text Available In this study presents the analyse of chrome iron cast structure (as-cast condition which are used in rugged conditions abrasion-percussive and high temperature. While producing the casts of chrome iron major influence has been preserve the structure of technologi cal process parameters. The addition to Fe-C-Cr alloy Ni, Mo or Cu and then proper heat treatment leads to the improvement of functional and mechanical cast qualities. Then it is possible to develop high mechanical properties which are recommended by PN-EN12513. As can it be seen from the above research silicon is an adverse chemical element in this kind of alloy cast iron. However, the reason of cracksappearing in chrome iron casts are phosphorus eutectic microareas. When the compound of Si and P reach the critical point, described inPN-88/H-83144 outdated standard, the microareas might appear.

  13. Impact strength and abrasion resistance of high strength concrete with rice husk ash and rubber tires

    Directory of Open Access Journals (Sweden)

    M. B. Barbosa

    Full Text Available The paper discusses the application of High Strength Concrete (HSC technology for concrete production with the incorporation of Rice Husk Ash (RHA residues by replacing a bulk of the material caking and rubber tires with partial aggregate volume, assessing their influence on the mechanical properties and durability. For concrete with RHA and rubber, it was possible to reduce the brittleness by increasing the energy absorbing capacity. With respect to abrasion, the RHA and rubber concretes showed lower mass loss than the concrete without residues, indicating that this material is attractive to be used in paving. It is thus hoped that these residues may represent a technological and ecological alternative for the production of concrete in construction works.

  14. Characterization and wear resistance of macro-arc oxidation coating on magnesium alloy AZ91 in simulated bedy fluids

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The mechanical characteristics ofthe macro-arc oxidation(MAO) coating on Mg alloy AZ91 were examined by means of nano scratch tester.The corrosion and erosion corrosion behavior of AZ91 with and without MAO coating were investigated by using potentiodynamic electrochemical technique and micro-abrasion tribometer in simulated body fluids,respectively.The influence of HCO3-ions on the erosion corrosion was discussed.The results show that the coating and its substrate are in a pronounced bond.The MAO coating inereases1-2 orders of magnitude of the corrosion resistance of AZ91 alloy.HCO3-ions enhance the corrosion rates of the AZ91 alloys more significantly than the alloys with MAO coating.However,there exists an obvious passivation process of AZ91 without coating in the HCO3-solutions.Moreover,an MgCO3 film formed in HCO3-containing solutions leads to an enhancement in micro-wear resistance.MAO coating deteriorates the erosion corrosion resistance of AZ91 alloy due to the formation of oxidation debris resulted from the broken MAO coating.

  15. Melamine Polyimide Composite Fire Resistant Intumescent Coatings

    Directory of Open Access Journals (Sweden)

    Satish Chandra Gupta

    2013-07-01

    Full Text Available Components of intumescent coatings acid source, carbon source and blowing agent like melamine linked together by a binder provide cumulative fire retardant properties. When temperature of the coating surface reaches a critical temperature under the heat of flame, the surface begins to melt and is converted into highly viscous liquid. Simultaneously, reactions are initiated that result in the release of inert gases with low thermal conductivity. These gases are trapped inside the viscous fluid forming insulating char. The special composite of melamine polyimide, a C source and melamine a blowing agent showed high performance heat resistance in the present study. Polyimides have excellent heat and chemical resistance, excellent adhesion to a number of substrates and superior mechanical properties, such as high flexural modulus and compressive strength. Polyimides are also known to possess outstanding dimensional stability under loads, which allows their use in high temperature environments. Effect of the monomer on chemical reactivity between the binder and the intumescent additives has been studied by thermo-gravimetric analysis, differential scanning calorimeter and FTIR analysis. Thermal insulation studies by various intumescent composite coatings, applied on aluminium plates provided useful time temperature profiles.Defence Science Journal, 2013, 63(4, pp.442-446, DOI:http://dx.doi.org/10.14429/dsj.63.4871

  16. Melamine Polyimide Composite Fire Resistant Intumescent Coatings

    Directory of Open Access Journals (Sweden)

    Satish Chandra Gupta

    2013-07-01

    Full Text Available Components of intumescent coatings acid source, carbon source and blowing agent like melamine linked together by a binder provide cumulative fire retardant properties. When temperature of the coating surface reaches a critical temperature under the heat of flame, the surface begins to melt and is converted into highly viscous liquid. Simultaneously, reactions are initiated that result in the release of inert gases with low thermal conductivity. These gases are trapped inside the viscous fluid forming insulating char. The special composite of melamine polyimide, a C source and melamine a blowing agent showed high performance heat resistance in the present study. Polyimides have excellent heat and chemical resistance, excellent adhesion to a number of substrates and superior mechanical properties, such as high flexural modulus and compressive strength. Polyimides are also known to possess outstanding dimensional stability under loads, which allows their use in high temperature environments. Effect of the monomer on chemical reactivity between the binder and the intumescent additives has been studied by thermo-gravimetric analysis, differential scanning calorimeter and FTIR analysis. Thermal insulation studies by various intumescent composite coatings, applied on aluminium plates provided useful time temperature profiles.

  17. Plasma powder coating of rods of hydraulic cylinders with white wear resistance cast iron

    Directory of Open Access Journals (Sweden)

    S. P. Nefedyev

    2014-01-01

    Full Text Available The article considers the features to form a structure and properties of Fe-C-Cr-V system coverings provided by the plasma and powder coating (build-up on the low carbon steel.It is shown that it is possible to restore a rod of hydraulic cylinders of small diameter by the plasma and powder coating. Thus, to avoid buckling and provide the built-up metal structure with the best wear resistance it is necessary to find a reasonable approach to a choice of the operation conditions to provide coating.The paper offers a way for efficient control of heat input at coating and a superheat value of the welding bath. It is noted that the coverings, which have been built up at the smallest heat input in a substrate, possess the best wear resistance, with a fusion zone formed with an austenitic crystallization interlayer.The paper defines consistent patterns to form a structure of coverings under various operation conditions of a plasma and powder coating. It shows the influence of the cooling speed after built-up metal crystallization on the formation of covering structure components.The paper formulates requirements for operation conditions of plasma and powder coating to provide coverings to be subjected to shock and abrasive wear, and shows the influence of additional heat treatment on formation of structure and properties of the built-up metal.The article under review meets available lacks in studying high-carbon chrome-vanadium coverings and is useful for scientists, graduates, and students investigating the wear resistance coating materials and effective methods for their deposition.

  18. Effect of heat treatment on the wear resistance of high-carbon and high-nitrogen steels subjected to abrasive wear

    Science.gov (United States)

    Filippov, M. A.; Belozerova, T. A.; Blinov, V. M.; Kostina, M. A.; Val'kov, E. V.

    2006-03-01

    The effect of quenching and tempering on the capacity of steels based on chromium-carbon, chromium-nitrogen, and carbon-manganese austenite for strain-induced martensitic transformation, hardening, and wear resistance in the process of abrasive wear is studied. The steels contain 1-1.2% C or N and 18% Cr or Mn. The wear resistance of the studied steels having a structure of metastable austenite is compared to that of steel 110G13.

  19. Photoresist-free patterning by mechanical abrasion of water-soluble lift-off resists and bare substrates: toward green fabrication of transparent electrodes.

    Science.gov (United States)

    Printz, Adam D; Chan, Esther; Liong, Celine; Martinez, René S; Lipomi, Darren J

    2013-01-01

    This paper describes the fabrication of transparent electrodes based on grids of copper microwires using a non-photolithographic process. The process--"abrasion lithography"--takes two forms. In the first implementation (Method I), a water-soluble commodity polymer film is abraded with a sharp tool, coated with a conductive film, and developed by immersion in water. Water dissolves the polymer film and lifts off the conductive film in the unabraded areas. In the second implementation (Method II), the substrate is abraded directly by scratching with a sharp tool (i.e., no polymer film necessary). The abraded regions of the substrate are recessed and roughened. Following deposition of a conductive film, the lower profile and roughened topography in the abraded regions prevents mechanical exfoliation of the conductive film using adhesive tape, and thus the conductive film remains only where the substrate is scratched. As an application, conductive grids exhibit average sheet resistances of 17 Ω sq(-1) and transparencies of 86% are fabricated and used as the anode in organic photovoltaic cells in concert with the conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). Compared to devices in which PEDOT:PSS alone serves as an anode, devices comprising grids of copper/nickel microwires and PEDOT:PSS exhibit lowered series resistance, which manifests in greater fill factor and power conversion efficiency. This simple method of forming micropatterns could find use in applications where cost and environmental impact should be minimized, especially as a potential replacement for the transparent electrode indium tin oxide (ITO) in thin-film electronics over large areas (i.e., solar cells) or as a method of rapid prototyping for laboratory-scale devices.

  20. Photoresist-free patterning by mechanical abrasion of water-soluble lift-off resists and bare substrates: toward green fabrication of transparent electrodes.

    Directory of Open Access Journals (Sweden)

    Adam D Printz

    Full Text Available This paper describes the fabrication of transparent electrodes based on grids of copper microwires using a non-photolithographic process. The process--"abrasion lithography"--takes two forms. In the first implementation (Method I, a water-soluble commodity polymer film is abraded with a sharp tool, coated with a conductive film, and developed by immersion in water. Water dissolves the polymer film and lifts off the conductive film in the unabraded areas. In the second implementation (Method II, the substrate is abraded directly by scratching with a sharp tool (i.e., no polymer film necessary. The abraded regions of the substrate are recessed and roughened. Following deposition of a conductive film, the lower profile and roughened topography in the abraded regions prevents mechanical exfoliation of the conductive film using adhesive tape, and thus the conductive film remains only where the substrate is scratched. As an application, conductive grids exhibit average sheet resistances of 17 Ω sq(-1 and transparencies of 86% are fabricated and used as the anode in organic photovoltaic cells in concert with the conductive polymer, poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS. Compared to devices in which PEDOT:PSS alone serves as an anode, devices comprising grids of copper/nickel microwires and PEDOT:PSS exhibit lowered series resistance, which manifests in greater fill factor and power conversion efficiency. This simple method of forming micropatterns could find use in applications where cost and environmental impact should be minimized, especially as a potential replacement for the transparent electrode indium tin oxide (ITO in thin-film electronics over large areas (i.e., solar cells or as a method of rapid prototyping for laboratory-scale devices.

  1. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

    2007-01-01

    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  2. Laboratory evaluation of toothbrush/toothpaste abrasion resistance after smooth enamel surface sealing.

    Science.gov (United States)

    Korbmacher-Steiner, Heike M; Schilling, Arndt F; Huck, Lothar G; Kahl-Nieke, Bärbel; Amling, Michael

    2013-04-01

    The use of dental sealants has been extended to smooth enamel surfaces. The present study was conducted to test the in vitro performance of four sealants with different characteristics (highly and lowly filled, self-etching features). Eighty human teeth (lower incisors and premolars) were randomly divided into following sealant test groups: ProSeal(TM), LightBond(TM), OrthoSolo(TM), and Seal&Protect(®). Twenty untreated teeth served as a control group. Tooth brushing was conducted for a period of time simulating 12, 18, and 24 months. During the toothbrush abrasion protocol, the specimens were subjected to thermal and acidic challenge. Sealant thickness was determined with μCT imaging, and qualitative and quantitative surface effects were investigated using stereo microscopy and raster electron microscopy, respectively. Data were subjected to t test or Kruskal-Wallis/Mann-Whitney tests (alpha, 5%). The wear behavior and film integrity of highly filled sealants were superior to lowly filled sealants. Even after 1 year of tooth brushing, significant surface deterioration with deleterious loss of enamel and discoloration was observed in all tested materials (χ(2) = 15.349; P = 0.004). The size of the observed defects increased over time. These results suggest that the application of sealants on smooth enamel surfaces should be limited to special indications, and their usefulness has to be revisited. Based on the results of this in vitro study, the general overall application of enamel sealants needs to be questioned.

  3. Influence of Processing and Heat Treatment on Corrosion Resistance and Properties of High Alloyed Steel Coatings

    Science.gov (United States)

    Hill, Horst; Weber, Sebastian; Raab, Ulrich; Theisen, Werner; Wagner, Lothar

    2012-09-01

    Corrosion and abrasive wear are two important aspects to be considered in numerous engineering applications. Looking at steels, high-chromium high-carbon tool steels are proper and cost-efficient materials. They can either be put into service as bulk materials or used as comparatively thin coatings to protect lower alloyed construction or heat treatable steels from wear and corrosion. In this study, two different corrosion resistant tool steels were used for the production of coatings and bulk material. They were processed by thermal spraying and super solidus liquid phase sintering as both processes can generally be applied to produce coatings on low alloyed substrates. Thermally sprayed (high velocity oxygen fuel) coatings were investigated in the as-processed state, which is the most commonly used condition for technical applications, and after a quenching and tempering treatment. In comparison, sintered steels were analyzed in the quenched and tempered condition only. Significant influence of alloy chemistry, processing route, and heat treatment on tribological properties was found. Experimental investigations were supported by computational thermodynamics aiming at an improvement of tribological and corrosive resistance.

  4. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  5. Corneal Abrasions

    Science.gov (United States)

    ... and lead to a serious condition called a corneal ulcer . That's why it's important to see a doctor to get a corneal abrasion checked out. What Causes a Corneal ... and land on your cornea, tears help to wash the particles away. Sometimes, ...

  6. Research on abrasion resistance technique for sinter single-roll crusher%烧结矿单辊破碎机抗磨损技术研究

    Institute of Scientific and Technical Information of China (English)

    陈方述; 聂松辉; 周卓林

    2011-01-01

    Sinter single-roll crusher is an important component of the sinter production line ,which operating environment and nature decides that it must possess properties of high-temperature resistance and abrasion resistance.First the invalid reasons and abrasive wear mechanism are studied aim at the problems of easy worn and short service life of the single-roll crusher.A conclusion is made that the abrasion pattern is abrasive wear happens under high-temperature environment with forms of chiseling and cutting.Then a structural design with abrasion resistance is studied ,simultaneously its materials selection and hardfacing technics are also analyzed and discussed.Afterwards ,one single-roll crusher with characteristics of long service life and abrasion resistance is designed.which is proved in the engineering practice that the proposed anti-wear technology for single-roll crusher is viable and effective.%单辊破碎机是烧结矿生产线上一个重要的部件,其工作环境与性质决定其必须具有抗高温与耐磨损的特性.针对目前单辊破碎机易磨损、寿命短的问题,首先,对其失效原因与磨损机理等方面进行了研究,得出其主要磨损形式是高温环境下带有凿削形式磨损的磨粒磨损.然后,研究了其抗磨损结构设计的方法,并对其材料选择与耐磨堆焊工艺等进行了详细分析与探讨,设计了一种抗磨损的长寿命烧结矿单辊破碎机.最后,通过工程实际使用验证了提出的单辊破碎枳抗磨损技术是可行且有效的.

  7. Development of (fe–b–c-based filler for wear-resistant composite coatings

    Directory of Open Access Journals (Sweden)

    О. V. Sukhovа

    2014-12-01

    value. Owing to multiple alloying of the filler based on Fe–В–С peritectic alloy with chromium, vanadium, molybdenum and niobium the abrasive wear resistance of composite coatings can be compared with that of tungsten-containing coatings, which ensures saving of expensive and deficient materials.

  8. Influences of the microstructure on the wear resistance of cobalt-based ahoy coatings obtained by plasma transferred arc process

    Institute of Scientific and Technical Information of China (English)

    HOU Qingyu; GAO Jiasheng

    2005-01-01

    The microstructure, substructure, and wear characteristic of cobalt-based alloy coatings obtained by plasma transferred arc (PTA) process were investigated using optical metallurgical microscope, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and dry sand abrasion tester (DSAT). The aging effect on the structure and wear resistance of the cobalt-based PTA coating was also studied. The results show that the as-welded coating consists of cobalt-based solid solution with face-centered cubic structure and hexagonal (Cr, Fe)7C3. There are a lot of stacking faults existing in the cobalt-based solid solution. After aging at 600℃ for 60 h, the microstructure becomes coarse, and another carbide (Cr, Fe)23C6 precipitates. As a result, the wear mass loss of the aged sample is higher than that of the as-welded sample.

  9. Influence of Vanadium and Boron Additions on the Microstructure, Fracture Toughness, and Abrasion Resistance of Martensite-Carbide Composite Cast Steel

    Directory of Open Access Journals (Sweden)

    Waleed Elghazaly

    2016-01-01

    Full Text Available High chromium cast steel alloys are being used extensively in many industrial services where dry or wet abrasion resistance is required. Such steel castings are demanded for cement, stoneware pipes, and earth moving industries. In this research, five steel heats were prepared in 100 kg and one-ton medium frequency induction furnaces and then sand cast in both Y-block and final impact arm spare parts, respectively. Vanadium (0.5–2.5% and boron (120–150 ppm were added to the 18Cr-1.9C-0.5Mo steel heats to examine their effects on the steel microstructure, mechanical properties especially impact, fracture toughness and abrasion resistance. Changes in the phase transformation after heat treatment were examined using inverted, SEM-EDX microscopy; however, the abrasion resistance was measured in dry basis using the real tonnage of crushed and milled stoneware clay to less than 0.1 mm size distribution.

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

    CSIR Research Space (South Africa)

    Lovelock, HDL

    1998-01-01

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

  11. Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

    Science.gov (United States)

    Gajek, M.; Lis, J.; Partyka, J.; Wójczyk, M.

    2011-10-01

    The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al2O3-SiO2, have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO2, ZrO2, V2O5 on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6~8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm2 (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5~6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO2-Al2O3, were examined with use of DTA, XRD and SEM methods.

  12. Rubberized Concrete Durability Against Abrasion

    Directory of Open Access Journals (Sweden)

    Md Noor Nurazuwa

    2016-01-01

    Full Text Available Durability performance of rubberized concrete against abrasion is presented in this paper. Surface depth loss was measured when abrasion load was constantly applied on concrete surface at each 500 interval rotation. Specimen with water-to cement ratio of 0.50 and 0.35 was prepared and tested at 28 days of curing age. In addition, 10% silica fume, SF was added to provide denser concrete and to understand its effectiveness against wear when added with crumb rubber. Results showed that crumb rubber shows good potential in providing abrasion resistance to concrete mix. However, in the case of rubberized concrete with silica fume, abrasion resistance was found to be slightly decreased with compressive strength more than 50N/mm2 due to the lack of low elastic modulus of CR particles to accommodate with denser cement matrix.

  13. Hydroxyapatite/poly(epsilon-caprolactone) double coating on magnesium for enhanced corrosion resistance and coating flexibility.

    Science.gov (United States)

    Jo, Ji-Hoon; Li, Yuanlong; Kim, Sae-Mi; Kim, Hyoun-Ee; Koh, Young-Hag

    2013-11-01

    Hydroxyapatite was deposited on pure magnesium (Mg) with a flexible poly(ε-caprolactone) interlayer to reduce the corrosion rate of Mg and enhance coating flexibility. The poly(ε-caprolactone) interlayer was uniformly coated on Mg by a spraying method, followed by hydroxyapatite deposition on the poly(ε-caprolactone) using an aerosol deposition method. In scanning electron microscopy observations, inorganic/organic composite-like structure was observed between the hydroxyapatite and poly(ε-caprolactone) layers, resulting from the collisions of hydroxyapatite particles into the poly(ε-caprolactone) matrix at the initial stage of the aerosol deposition. The corrosion resistance of the coated Mg was examined using potentiodynamic polarization tests. The hydroxyapatite/poly(ε-caprolactone) double coating remarkably improved the corrosion resistance of Mg in Hank's solution. In the in vitro cell tests, the coated Mg showed better cell adhesion compared with the bare Mg due to the reduced corrosion rate and enhanced biocompatibility. The stability and flexibility of hydroxyapatite/poly(ε-caprolactone) double coating was investigated by scanning electron microscopy inspections after the coated Mg was deformed. The hydroxyapatite coating on the poly(ε-caprolactone) interlayer revealed enhanced coating stability and flexibility without cracking or delamination during bending and stretching compared with the hydroxyapatite single coating. These results demonstrated that the hydroxyapatite/poly(ε-caprolactone) double coating significantly improved the surface corrosion resistance of Mg and enhanced coating flexibility for use of Mg as a biodegradable implant.

  14. High gain durable anti-reflective coating with oblate voids

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev

    2016-06-28

    Disclosed herein are single layer transparent coatings with an anti-reflective property, a hydrophobic property, and that are highly abrasion resistant. The single layer transparent coatings contain a plurality of oblate voids. At least 1% of the oblate voids are open to a surface of the single layer transparent coatings.

  15. Microstructure and Abrasive Wear Resistance of 18Cr-4Ni-2.5Mo Cast Steel

    Directory of Open Access Journals (Sweden)

    B. Kalandyk

    2012-12-01

    Full Text Available An influence of a decreased Cr content on the microstructure of the highly alloyed Cr-Ni cast steel, duplex type, melted under laboratoryconditions, was characterized in the paper. The microstructure investigations were performed in the initial state and after the heat treatment (solution annealing at 1060C as well as the phase transformation kinetics at continuous cooling was measured. The wear resistance of the investigated cast steel was tested and compared with the 24%Cr-5%Ni-2.5%Mo cast steel.The Cr content decrease, in ferritic-austenitic cast steels (duplex, from 24-26%Cr to 18% leads to the changes of the castingsmicrostructure and eliminating of a brittle  phase. In dependence of the casting cooling rate, apart from ferrite and austenite, also fine martensite precipitates occur in the casting structure. It was shown that the investigated cast steel is characterised by a slightly lower wear resistance than the typical cast steel duplex grades.

  16. Wear and impact resistance of HVOF sprayedceramic matrix composites coating

    Science.gov (United States)

    Prawara, B.; Martides, E.; Priyono, B.; Ardy, H.; Rikardo, N.

    2016-02-01

    Ceramic coating has the mechanical properties of high hardness and it is well known for application on wear resistance, but on the other hand the resistance to impact load is low. Therefore its use is limited to applications that have no impact loading. The aim of this research was to obtain ceramic-metallic composite coating which has improved impact resistance compared to conventional ceramic coating. The high impact resistance of ceramic-metallic composite coating is obtained from dispersed metallic alloy phase in ceramic matrix. Ceramic Matrix Composites (CMC) powder with chrome carbide (Cr3C2) base and ceramic-metal NiAl-Al2O3 with various particle sizes as reinforced particle was deposited on mild steel substrate with High Velocity Oxygen Fuel (HVOF) thermal spray coating. Repeated impact test showed that reinforced metallic phase size influenced impact resistance of CMC coating. The ability of CMC coating to absorb impact energy has improved eight times and ten times compared with original Cr3C2 and hard chrome plating respectively. On the other hand the high temperature corrosion resistance of CMC coating showed up to 31 cycles of heating at 800°C and water quenching cooling.

  17. Abrasive Performance of Chromium Carbide Reinforced Ni3Al Matrix Composite Cladding

    Institute of Scientific and Technical Information of China (English)

    LI Shang-ping; LUO He-li; FENG Di; CAO Xu; ZHANG Xi-e

    2009-01-01

    The Microstructure and room temperature abrasive wear resistance of chromium carbide reinforced NiM3Al matrix composite cladding at different depth on nickel base alloy were investigated. The results showed that there is a great difference in microstructure and wear resistance of the Ni3 Al matrix composite at different depth. Three kinds of tests, designed for different load and abrasive size, were used to understand the wear behaviour of this material. Under all three wear conditions, the abrasion resistance of the composite cladding at the depth of 6 mm, namely NC-M2, was much higher than that of the composite cladding at the depth of 2 mm, namely NC-M1. In addition, the wear-resistant advantage of NC-M2 was more obvious when the size of the abrasive was small. The relative wear resistance of NC-M2 increased from 1.63 times to 2.05 times when the size of the abrasive decreased from 180 μm to 50μm. The mierostructure of the composite cladding showed that the size of chromium carbide particles, which was mainly influenced by cooling rate of melting pool, was a function of distance from the interface between the coating and substrate varied gradually. The chromium carbide particles near the interface were finer than that far from inter-face, which was the main reason for the different wear resistance of the composite cladding at different depth.

  18. Abrasion test of flexible protective materials on hydraulic structures

    Directory of Open Access Journals (Sweden)

    Xin WANG

    2014-01-01

    Full Text Available In this study, several kinds of flexible protective materials sprayed with polyurea elastomers (hereinafter referred to as polyurea elastomer protective material were adopted to meet the abrasion resistance requirement of hydraulic structures, and their abrasion resistances against the water flow with suspended load or bed load were studied systematically through tests. Natural basalt stones were adopted as the abrasive for simulation of the abrasion effect of the water flow with bed load, and test results indicate that the basalt stone is suitable for use in the abrasion resistance test of the flexible protective material. The wear process of the polyurea elastomer protective material is stable, and the wear loss is linear with the time of abrasion. If the wear thickness is regarded as the abrasion resistance evaluation factor, the abrasion resistance of the 351 pure polyurea is about twice those of pure polyurea with a high level of hardness and aliphatic polyurea, and over five times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with suspended load. It is also about 50 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load. Overall, the abrasion resistance of pure polyurea presented a decreasing trend with increasing hardness. Pure polyurea with a Shore hardness of D30 has the best abrasion resistance, which is 60 to 70 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load, and has been recommended, among the five kinds of pure polyurea materials with different hardness, in anti-abrasion protection of hydraulic structures.

  19. Effect of denture cleaning on abrasion resistance and surface topography of polymerized CAD CAM acrylic resin denture base.

    Science.gov (United States)

    Shinawi, Lana Ahmed

    2017-05-01

    The application of computer-aided design computer-aided manufacturing (CAD CAM) technology in the fabrication of complete dentures, offers numerous advantages as it provides optimum fit and eliminates polymerization shrinkage of the acrylic base. Additionally, the porosity and surface roughness of CAD CAM resins is less compared to conventionally processed resins which leads to a decrease in the adhesion of bacteria on the denture base, which is associated with many conditions including halitosis and aspiration pneumonia in elderly denture wearers. To evaluate the influence of tooth brushing with dentifrices on CAD CAM resin blocks in terms of abrasion resistance, surface roughness and scanning electron photomicrography. This experimental study was carried out at the Faculty of Dentistry of King Abdulaziz University during 2016. A total of 40 rectangular shaped polymerized CAD CAM resin samples were subjected to 40.000 and 60.000 brushing strokes under a 200-gram vertical load simulating three years of tooth brushing strokes using commercially available denture cleaning dentifrice. Data were analyzed by SPSS version 20, using descriptive statistics and ANOVA. ANOVA test revealed a statistical significant weight loss of CAD CAM acrylic resin denture base specimens following 40.000 and 60.000 brushing strokes as well as a statistical significant change (p=0.0.5) in the surface roughness following brushing. The CAD CAM resin samples SEM baseline imaging revealed a relatively smooth homogenous surface, but following 40,000 and 60,000 brushing strokes, imaging displayed the presence of small scratches on the surface. CAD CAM resin displayed a homogenous surface initially with low surface roughness that was significantly affected following simulating three years of manual brushing, but despite the significant weight loss, the findings are within the clinically acceptable limits.

  20. Effect of Age-Hardening Treatment on Microstructure and Sliding Wear-Resistance Performance of WC/Cu-Ni-Mn Composite Coatings

    Science.gov (United States)

    Liu, Jun; Yang, Shuai; Liu, Kai; Gui, Chibin; Xia, Weisheng

    2017-06-01

    The Cu-Ni-Mn alloy-based hardfacing coatings reinforced by WC particles (WC/Cu-Ni-Mn) were deposited on a steel substrate by a manual oxy-acetylene weld hardfacing method. A sound interfacial junction was formed between the WC particles and the Cu-Ni-Mn alloy metal matrix binder even after the age-hardening treatment. The friction and wear behavior of the hardfacing coatings was investigated. With the introduction of WC particles, the sliding wear resistance of the WC/Cu-Ni-Mn hardfacing coatings was sharply improved: more than 200 times better than that of the age-hardening-treated Cu-Ni-Mn alloy coating. The sliding wear resistances of the as-deposited and the age-hardening-treated WC/Cu-Ni-Mn hardfacing coatings were 1.83 and 2.26 times higher than that of the commercial Fe-Cr-C hardfacing coating, which is mainly ascribed to the higher volume fraction of carbide reinforcement. Owing to the precipitation of the NiMn secondary phase in the Cu-Ni-Mn metal matrix, the age-hardening-treated coating had better wear resistance than that of the as-deposited coating. The main sliding wear mechanisms of the age-hardening-treated coatings are adhesion and abrasion.

  1. Efficiency of protective coatings on high creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-04-01

    Full Text Available This paper presents results of research of multilayer aluminium–silicon coatings. Aluminium–silicon coatings were created on high–temperature creep resist cast iron using slurry method in air atmosphere. These coatings protect equipment against hot corrosionin carburizing atmosphere at thermal shocks conditions.Various technological parameters of coatings manufacturing were applied. Main technological parameters were: temperature and time ofannealing and Al-Si ratio in the active mixture. The structure of obtained coatings is three-zonal. Phase composition of two external zones ensures protection against carburizing, but these zones are not resistant to cracking. The cracks form as a result of thermal shocks. The internal zone of the coatings situated next to substrate compensates for differences of thermal expansion of the coating and the substrate. The cracks are stopped in the internal zone and do not propagate into the substrate material. Protective efficiency of the coatings at carburizing conditions with thermal shocks was determined. Structure of the coatings before and after carburizing and thermal shocks is described in present paper. Thickness, chemical composition (EDS and phase composition (XRD of the coatings are determined. Correlation between the coatings structure and depth of carburized layer was determined.

  2. Antifriction and wear resistance of tin diffusion coating on brass

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    After brass is coated with tin, heat treatment makes the coating metal Sn and the substrate metal lic elements Cu and Zn diffuse with each other. This causes the c oating composition to be changed and the interface to be strengthened. The diffusion coating with a multiphase structure formed by this process has excellent properties of antifriction and wear resistance. With the aid of scanning electron microscopy, electronic probe microanalysis and X-ray diffraction, the mechanism of the properties is discussed.

  3. Corrosion resistant coatings suitable for elevated temperature application

    Science.gov (United States)

    Chan, Kwai S [San Antonio, TX; Cheruvu, Narayana Sastry [San Antonio, TX; Liang, Wuwei [Austin, TX

    2012-07-31

    The present invention relates to corrosion resistance coatings suitable for elevated temperature applications, which employ compositions of iron (Fe), chromium (Cr), nickel (Ni) and/or aluminum (Al). The compositions may be configured to regulate the diffusion of metals between a coating and a substrate, which may then influence coating performance, via the formation of an inter-diffusion barrier layer. The inter-diffusion barrier layer may comprise a face-centered cubic phase.

  4. Electrodeposition and Corrosion Resistance of Ni-Graphene Composite Coatings

    Science.gov (United States)

    Szeptycka, Benigna; Gajewska-Midzialek, Anna; Babul, Tomasz

    2016-08-01

    The research on the graphene application for the electrodeposition of nickel composite coatings was conducted. The study assessed an important role of graphene in an increased corrosion resistance of these coatings. Watts-type nickel plating bath with low concentration of nickel ions, organic addition agents, and graphene as dispersed particles were used for deposition of the composite coatings nickel-graphene. The results of investigations of composite coatings nickel-graphene deposited from the bath containing 0.33, 0.5, and 1 g/dm3 graphene and one surface-active substance were shown. The contents of particles in coatings, the surface morphology, the cross-sectional structures of the coated samples, and their thickness and the internal stresses were studied. Voltammetric method was used for examination of the corrosion resistance of samples of composite coatings in 0.5 M NaCl. The obtained results suggest that the content of incorporated graphene particles increases with an increasing amount of graphene in plating bath. The application of organic compounds was advantageous because it caused compressive stresses in the deposited coatings. All of the nickel-graphene composite layers had better corrosion resistance than the nickel coating.

  5. Porosity and wear resistance of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermal-sprayed coatings offer practical and economical solutions for corrosion and wear protection of components or tools. To improve the coating properties, heat treatment such as preheat is applied. The selection of coating and substrate materials is a key factor in improving the quality of the coating morphology after the heat treatment. This paper presents the experimental results regarding the effect of preheat temperatures, i.e. 200°C, 300°C and 400°C, on porosity and wear resistance of tungsten carbide (WC) coating sprayed by flame thermal coating. The powders and coatings morphology were analyzed by a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectrometry (FE-SEM/EDS), whereas the phase identification was performed by X-Ray diffraction technique (XRD). In order to evaluate the quality of the flame spray obtained coatings, the porosity, micro-hardness and wear rate of the specimens was determined. The results showed that WC coating gives a higher surface hardness from 1391 HVN up to 1541 HVN compared to that of the non-coating. Moreover, the wear rate increased from 0.072 mm3/min. to 0.082 mm3/min. when preheat temperature was increased. Preheat on H13 steel substrate can reduce the percentage of porosity level from 10.24 % to 3.94% on the thermal spray coatings.

  6. Sol-gel derived contamination resistant antireflective coatings

    Science.gov (United States)

    Shen, Jun; Liu, Yuan; Wu, Guangming; Zhou, Bin; Zhang, Zhihua; Zhu, Yumei

    2011-02-01

    Silica-based sol-gel antireflective (AR) optical coatings are critical components for high peak power laser systems. It is well known that water vapor and volatile organic compounds in both the laser bay and target bay environments will reduce the antireflective efficiency and laser-damage resistance of the sol-gel AR coating. In this study, alkylation with organosilanes in the vapor state was investigated. Sol-gel AR coatings were vapor-phase treated with hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS) at room temperature, and the resulting post-treated sol-gel AR coatings were tested for their resistance to contamination by a series of volatile organic compounds. Contact angle measurements were taken to discern the degree of silanization. After the vapor treatment of sol-gel AR coatings with organosilanes, the spectral performance of the coatings were analyzed by spectrophotometer, both before and after the exposure to volatile organic compounds. It is found that the coatings treated with ammonia and HMDS show a better contamination resistant capability. After being contaminated 70 hours with hexane, the transmittance of the coatings presents no obvious decrease. And the vapor treatment produces an increase in their damage threshold at 1064 nm (10ns pulse width) as compared to untreated control samples.

  7. Corrosion Resistance of Ceramic Coating on Steel Substrate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fe/Al2O3 ceramic coating was made by spraying and sol-gel. The corrosion resistance between Fe/Al2O3 ceramic coating and steel 45# was studied. By microscope and X-ray diffraction, the binding and the composition of the interface were also analyzed. The results showed that Fe/Al2O3 ceramic coating had dense structure, less porosity and better binding with the substrate which was effective to prevent erosive liquor immersing into the inside of ceramic coating. Some substances that distributed homogeneously in Fe/Al2O3 ceramic coating,such as α-Al2O3, FeAlO3 and Fe3Al, could improve the corrosion resistance of this material.

  8. Effect of UV/EB radiation dosages on the properties of nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Nik Salleh, Nik Ghazali, E-mail: Nik_Ghazali@nuclearmalaysia.gov.m [Malaysian Nuclear Agency, Block 42, Radiation Curing and Synthesis Group, Bangi, 43000 Kajang, Selangor (Malaysia); Firdaus Yhaya, Mohd; Hassan, Azman; Abu Bakar, Aznizam; Mokhtar, Munirah [Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2011-02-15

    The aim of this study was to compare the effects of ultraviolet (UV) and electron beam (EB) radiation on the properties of cured nanocomposite coatings. Surface hardness increased with increase in radiation dosages (number of passes) for all samples. This was due to the increase in crosslinking with increase in radiation dosage. Pendulum hardness, gel content, and thumb twist results were analyzed to choose appropriate curing dosage for both curing techniques. The selected dosages were then used to cure coatings for scratch and abrasion resistance tests. It was found that the UV curing produced coatings with better abrasion resistance, whereas EB curing was a more suitable approach for producing scratch resistance coatings.

  9. Theoretical analysis of thermal shock resistance of ceramic foam coatings

    Science.gov (United States)

    Zhang, Y. X.; Wang, B. L.

    2017-01-01

    Ceramic foams have a high resistance to corrosion and wear. They also have a good thermal insulation performance because of their high melting point and low thermal conductivity. The thermal shock resistance of a ceramic foam coating with an edge crack under a sudden temperature variation is investigated. The dynamic thermal stress fields in the ceramic foam coating are obtained. Using the superposition principle, the crack problem of the ceramic foam coating is reduced to the solution of a set of singular integral equations. Propagation of the edge crack is analyzed. Effects of the relative density and thermal properties of the ceramic foam and of crack length on the thermal shock resistance are identified. The results obtained can be useful in designing thermal protective ceramic materials for thermal barrier coatings.

  10. Optically transparent, scratch-resistant, diamond-like carbon coatings

    Science.gov (United States)

    He, Xiao-Ming; Lee, Deok-Hyung; Nastasi, Michael A.; Walter, Kevin C.; Tuszewski, Michel G.

    2003-06-03

    A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleable to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit adherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced coatings having improved optical properties and lower coating stress levels, but with slightly lower hardness.

  11. Clasp retention and composites: an abrasion study.

    Science.gov (United States)

    Davenport, J C; Hawamdeh, K; Harrington, E; Wilson, H J

    1990-08-01

    An in vitro test for screening the abrasion resistance and abrasivity of composite resins when used to provide tooth undercuts for removable partial denture clasps is described. In the present study nine composite resins were tested against wrought stainless steel round clasps. The results indicated that the abrasion of any of the composites tested was unlikely to cause a noticeable loss of retention in the clinical situation. However, there was marked abrasion of the clasps by two of the composites which would be likely to be clinically relevant.

  12. Effect of residual stresses on the strength, adhesion and wear resistance of SiC coatings obtained by plasma-enhanced chemical vapor deposition on low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Kattamis, T.Z. (Department of Metallurgy, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136 (United States)); Chen, M. (Department of Metallurgy, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136 (United States)); Skolianos, S. (Aristoteles University, Thessaloniki (Greece)); Chambers, B.V. (Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States))

    1994-11-01

    Amorphous hydrogenated silicon carbide thin coatings were deposited on AISI 4340 low alloy steel wafers and thicker steel specimens by plasma-enhanced chemical vapor deposition. The cohesion of the coating, its adhesion to the substrate and its friction coefficient were evaluated by automatic scratch testing, and its wear resistance by pin-on-disk tribometry. During annealing, the residual stress attributed to hydrogen entrapment during deposition gradually changed from compressive to tensile and its rate of increase decreased with increasing annealing time. The cohesion and adhesion failure loads and the abrasive wear resistance decreased with decreasing residual compressive stress and increasing residual tensile stress. The friction coefficient between the coating surface and a diamond stylus decreased with increasing annealing time. ((orig.))

  13. Oxidation resistant nanocrystalline MCrAl(Y) coatings and methods of forming such coatings

    Science.gov (United States)

    Cheruvu, Narayana S.; Wei, Ronghua

    2014-07-29

    The present disclosure relates to an oxidation resistant nanocrystalline coating and a method of forming an oxidation resistant nanocrystalline coating. An oxidation resistant coating comprising an MCrAl(Y) alloy may be deposited on a substrate, wherein M, includes iron, nickel, cobalt, or combinations thereof present greater than 50 wt % of the MCrAl(Y) alloy, chromium is present in the range of 15 wt % to 30 wt % of the MCrAl(Y) alloy, aluminum is present in the range of 6 wt % to 12 wt % of the MCrAl(Y) alloy and yttrium, is optionally present in the range of 0.1 wt % to 0.5 wt % of the MCrAl(Y) alloy. In addition, the coating may exhibit a grain size of 200 nm or less as deposited.

  14. Frost resistance of concrete surfaces coated with waterproofing materials

    Science.gov (United States)

    Klovas, A.; Dauksys, M.; Ciuprovaite, G.

    2015-03-01

    Present research lays emphasis on the problem of concrete surface exposed to aggressive surrounding quality. The test was conducted with concrete surfaces coated with different waterproofing materials exposed in solution of 3 % of sodium sulphate. Research was performed according to LST EN 1338:2003 standard requirements. Technological properties of concrete mixture as well as physical-mechanical properties of formed concrete specimens were established. The resistance of concrete to freezing - thawing cycles was prognosticated according to the porosity parameters established by the kinetic of water absorption. Five different waterproofing materials (coatings) such as liquid bitumen-rubber based, elastic fiber-strengthened, silane-siloxane based emulsion, mineral binder based and liquid rubber (caoutchouc) based coatings were used. Losses by mass of coating materials and specimens surface fractures were calculated based on the results of frost resistance test. Open code program "ImageJ" was used for visual analysis of concrete specimens. Based on the results, aggressive surrounding did not influence specimens coated with elastic, fibre-strengthened, mineral materials. On the other hand, specimens coated with liquid rubber (caoutchouc) based material were greatly influenced by aggressive surrounding. The biggest losses of specimen surface concrete (fractures) were obtained with silane-siloxane based emulsion coating. Generally, specimens coated with waterproofing materials were less influenced by aggressive surrounding compared with those without.

  15. Wear resistance of reactive plasma sprayed and laser remelted TiB2-TiC0.3N0.7 based composite coatings against medium carbon steel

    Science.gov (United States)

    Mao, Zhengping; Wang, Jun; Sun, Baode; Bordia, Rajendra K.

    2011-01-01

    Wear resistance of reactive plasma sprayed TiB2-TiC0.3N0.7 based composite coatings and the as-sprayed coating with laser surface treatment was investigated using plate-on-plate tests. Wear tests were performed at different normal loads and sliding speeds under dry sliding conditions in air. The surface morphologies of counterparts against as-sprayed and laser remelted coatings were investigated. The microstructure and chemical composition of wear debris and coatings were studied using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The results show that the wear resistance of the laser remelted coating is improved significantly due to their increased microhardness and reduced flaws. The primary wear mechanism of the remelted coating is oxidation wear and its minor wear mechanisms are grain abrasion and fatigue failure during the course of wear test. In contrast, the primary wear mechanism of the as-sprayed coating is grain abrasion at the low sliding speed (370 rpm) and fatigue failure at the high sliding speed (549 rpm). The oxidation wear mechanism is a minor contributor for the as-sprayed coating.

  16. Microstructure and abrasion wear behavior of Ni-based laser cladding alloy layer at high temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LIU Su-qin; WANG Shun-xing

    2005-01-01

    Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high temperature by changing compositions and temperatures were investigated by means of optical microscope and scanning electron microscope. Among the three compositions of cladding layer, i.e. Ni21+20%WC+0.5%CeO2, Ni25+20%WC+0.5%CeO2 and Ni60+20%WC+0.5%CeO2, the experimental results show that Ni21+20%WC+0.5%CeO2 cladding layer is made up of finer grains, and presents the best abrasion wear behavior at high temperature. The wear pattern of laser cladding layer is mainly grain abrasion at lower temperature, and it would be changed to adhesive abrasion and oxide abrasion at higher temperature.

  17. Enhancement of Corrosion Resistance of Zinc Coatings Using Green Additives

    Science.gov (United States)

    Punith Kumar, M. K.; Srivastava, Chandan

    2014-10-01

    In the present work, morphology, microstructure, and electrochemical behavior of Zn coatings containing non-toxic additives have been investigated. Zn coatings were electrodeposited over mild steel substrates using Zn sulphate baths containing four different organic additives: sodium gluconate, dextrose, dextrin, and saccharin. All these additives are "green" and can be derived from food contents. Morphological and structural characterization using electron microscopy, x-ray diffraction, and texture co-efficient analysis revealed an appreciable alteration in the morphology and texture of the deposit depending on the type of additive used in the Zn plating bath. All the Zn coatings, however, were nano-crystalline irrespective of the type of additive used. Polarization and electrochemical impedance spectroscopic analysis, used to investigate the effect of the change in microstructure and morphology on corrosion resistance behavior, illustrated an improved corrosion resistance for Zn deposits obtained from plating bath containing additives as compared to the pure Zn coatings.

  18. Corrosion Resistance of Zinc Coatings With Aluminium Additive

    Directory of Open Access Journals (Sweden)

    Votava Jiří

    2014-08-01

    Full Text Available This paper is focused on evaluation of anticorrosion protection of inorganic metal coatings such as hot-dipped zinc and zinc-galvanized coatings. The thickness and weight of coatings were tested. Further, the evaluation of ductile characteristics in compliance with the norm ČSN EN ISO 20482 was processed. Based on the scratch tests, there was evaluated undercorrosion in the area of artificially made cut. Corrosion resistance was evaluated in compliance with the norm ČSN EN ISO 9227 (salt-spray test. Based on the results of the anticorrosion test, there can be stated corrosion resistance of each individual protective coating. Tests were processed under laboratory conditions and may vary from tests processed under conditions of normal atmosphere.

  19. Heat Resistance of TiN Coated HSS Tools

    Institute of Scientific and Technical Information of China (English)

    周兰英; 周焕雷; 贾庆莲

    2003-01-01

    The cutting friction, cutting deformation, producing heat, conducting heat, temperature field of TiN coated HSS tools in the cutting process are discussed profoundly. In order to make clear the heat property of TiN coated tools, from the micromechanism angle, the relationship of the heat property and the crystal structure of TiN compound is analyzed, and the regularity of TiN compound crystal structure changing with temperature rising is sought. The difference of the wear resistance and heat resistance of TiN coated tools deposited by c1 and c2 depositing techniques is proved by tests. The conclusions will offer the theoretical basis for correct design of geometrical parameters of TiN coated tools, rational selection of cutting regimes and optimization of the depositing technique.

  20. Improvement in corrosion resistance of magnesium coating with cerium treatment

    Institute of Scientific and Technical Information of China (English)

    Samia Ben Hassen; Latifa Bousselmi; Patricc Bercot; El Mustafa Rezrazi; Ezzeddine Triki

    2009-01-01

    Corrosion protection afforded by a magnesium coating treated in cerium salt solution on steel substrate was investigated using open circuit potential, polarization curves, and electrochemical impedance spectroscopy (EIS) in 0.005 M sodium chloride solution (NaCl). The morphology of the surface was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The cerium treated coating was obtained by immersion in CeCl3 solution. The results showed that the corrosion resistance of the treated magnesium coating was improved. The corrosion potential of the treated coating was found to be nobler than that of the untreated magnesium coating and the corrosion current decreased significantly. Impedance results showed that the cerium treatment increased corrosion protection. The improvement of anti-corrosion properties was ataibuted to the formation of cerium oxides and hydroxides that gave to a physical barrier effect.

  1. Method of forming corrosion resistant coatings on metal articles

    Energy Technology Data Exchange (ETDEWEB)

    Restall, J.E.

    1983-05-10

    A metallic or ceramic layer is deposited on a component by plasma spraying. This produces a rough, still porous, coating which is poorly bonded at the interface with the substrate. Aluminium or chromium is vapor deposited under pulsating pressure to react with the substrate to form an oxidation resistant coating of Ni Al (intermetallic) or Ni Cr (solid solution) which may include ceramic particles and is aerodynamically smooth.

  2. Hydro-abrasive erosion: Problems and solutions

    Science.gov (United States)

    Winkler, K.

    2014-03-01

    The number of hydro power plants with hydro-abrasive erosion is increasing worldwide. An overall approach is needed to minimize the impact of this phenomenon. Already at the start of the planning phase an evaluation should be done to quantify the erosion and the impact on the operation. For this, the influencing parameters and their impact on the erosion have to be known. The necessary information for the evaluation comprises among others the future design, the particle parameters of the water, which will pass the turbine, and the power plant owner's framework for the future operation like availability or maximum allowable efficiency loss, before an overhaul needs to be done. Based on this evaluation of the erosion, an optimised solution can then be found, by analysing all measures in relation to investments, energy production and maintenance costs as decision parameters. Often a more erosion-resistant design, instead of choosing the turbine design with the highest efficiency, will lead to higher revenue. The paper will discuss the influencing parameters on hydro-abrasive erosion and the problems to acquire this information. There are different optimisation possibilities, which will be shown in different case studies. One key aspect to reduce the erosion and prolong the operation time of the components is to coat all relevant parts. But it is very important that this decision is taken early in the design stage, as the design has to be adapted to the requirements of the coating process. The quality of coatings and their impact on the operation will be discussed in detail in the paper as due to the non-availability of standards many questions arise in projects.

  3. RF surface resistance study of non-evaporable getter coatings

    Science.gov (United States)

    Malyshev, Oleg B.; Gurran, Lewis; Goudket, Philippe; Marinov, Kiril; Wilde, Stuart; Valizadeh, Reza; Burt, Graeme

    2017-02-01

    In many particle accelerators the beam parameters could be affected by the beam pipe wakefield impedance. It is vital to understand how the wakefield impedance might vary due to various coatings on the surface of the vacuum chamber, and this can be derived from surface resistance measurements. The bulk conductivity of two types of NEG films (dense and columnar) is determined. This is achieved by measuring the surface resistance of NEG-coated samples using an RF test cavity and fitting the experimental data to a standard theoretical model. The conductivity values obtained are then used to compare resistive wall wakefield effects in beam pipes coated with either of the two types of film.

  4. Advanced polymer-inorganic hybrid hard coatings utilizing in situ polymerization method.

    Science.gov (United States)

    Takaki, Toshihiko; Nishiura, Katsunori; Mizuta, Yasushi; Itou, Yuichi

    2006-12-01

    Hard coatings are frequently used to give plastics high scratch resistance. Coating hardness and adhesion to the substrate are considered to be key factors influencing scratch resistance, but it is difficult to produce coatings that have both properties. Hybridization of polymers and inorganic materials is a promising approach for solving this problem. We prepared polymer-silica hybrid coatings by using in situ polymerization to carry out radical polymerization of vinyl monomers in a sol-gel solution of alkoxysilanes, and measured the abrasion resistance of the coatings. However, the expected properties were not obtained because the sol-gel reaction did not perfectly proceed on the surface of the coatings under the N2 conditions. We found that curing the hybrid coatings by UV irradiation in air promoted the sol-gel reaction on the surface, resulting in coatings having excellent abrasion resistance.

  5. The corrosion resistance of zinc-nickel composite coatings

    OpenAIRE

    Panek, J; Bierska-Piech; M. Karolus

    2011-01-01

    Purpose: The aim of this work was to estimate the corrosion resistance of composite Zn+Ni and (Ni-Zn+Ni)/Zn coatings by salt spray test, electrochemical methods and grazing incidence X-ray diffraction (GIXD) method.Design/methodology/approach: The corrosion resistance properties of zinc-nickel coatings in 5% NaCl solution were investigated by salt spray test in 5% NaCl solution and electrochemical methods. Using Stern method the corrosion potential - Ecorr, corrosion current density - icorr,...

  6. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT--EVERMORE PAINTS AND COATINGS INC. FORMULA 5 COATING

    Science.gov (United States)

    This report is of a test of the pollution prevention capabilities of a polyamide-epoxy-silicone modified paint coating. It was analyzed for volatile organic emissions, hazardous air pollutants, film thickness, gloss, appearance, MEK rub resistance, abrasion resistance and other ...

  7. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT--EVERMORE PAINTS AND COATINGS INC. FORMULA 5 COATING

    Science.gov (United States)

    This report is of a test of the pollution prevention capabilities of a polyamide-epoxy-silicone modified paint coating. It was analyzed for volatile organic emissions, hazardous air pollutants, film thickness, gloss, appearance, MEK rub resistance, abrasion resistance and other ...

  8. Carbon Coating Of Copper By Arc-Discharge Pyrolysis

    Science.gov (United States)

    Ebihara, Ben T.; Jopek, Stanley

    1988-01-01

    Adherent, abrasion-resistant coat deposited with existing equipment. Carbon formed and deposited as coating on copper substrate by pyrolysis of hydrocarbon oil in electrical-arc discharges. Technique for producing carbon deposits on copper accomplished with electrical-discharge-machining equipment used for cutting metals. Applications for new coating technique include the following: solar-energy-collecting devices, coating of metals other than copper with carbon, and carburization of metal surfaces.

  9. Corrosion Resistant Coatings for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  10. A new methodology for hydro-abrasive erosion tests simulating penstock erosive flow

    Science.gov (United States)

    Aumelas, V.; Maj, G.; Le Calvé, P.; Smith, M.; Gambiez, B.; Mourrat, X.

    2016-11-01

    Hydro-abrasive resistance is an important property requirement for hydroelectric power plant penstock coating systems used by EDF. The selection of durable coating systems requires an experimental characterization of coating performance. This can be achieved by performing accelerated and representative laboratory tests. In case of severe erosion induced by a penstock flow, there is no suitable method or standard representative of real erosive flow conditions. The presented study aims at developing a new methodology and an associated laboratory experimental device. The objective of the laboratory apparatus is to subject coated test specimens to wear conditions similar to the ones generated at the penstock lower generatrix in actual flow conditions. Thirteen preselected coating solutions were first been tested during a 45 hours erosion test. A ranking of the thirteen coating solutions was then determined after characterisation. To complete this first evaluation and to determine the wear kinetic of the four best coating solutions, additional erosion tests were conducted with a longer duration of 216 hours. A comparison of this new method with standardized tests and with real service operating flow conditions is also discussed. To complete the final ranking based on hydro-abrasive erosion tests, some trial tests were carried out on penstock samples to check the application method of selected coating systems. The paper gives some perspectives related to erosion test methodologies for materials and coating solutions for hydraulic applications. The developed test method can also be applied in other fields.

  11. Machining with abrasives

    CERN Document Server

    Jackson, Mark J

    2011-01-01

    Abrasive machining is key to obtaining the desired geometry and surface quality in manufacturing. This book discusses the fundamentals and advances in the abrasive machining processes. It provides a complete overview of developing areas in the field.

  12. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Angel Sanjurjo

    2004-05-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. A review of the literature indicated that the Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. We selected diffusion coatings of Cr and Al, and surface coatings of Si and Ti for the preliminary testing. These coatings will be applied using the fluidized bed chemical vapor deposition technique developed at SRI which is rapid and relatively inexpensive. We have procured coupons of typical alloys used in a gasifier. These coupons will be coated with Cr, Al, Si, and Ti. The samples will be tested in a bench-scale reactor using simulated coal gas compositions. In addition, we will be sending coated samples for insertion in the gas stream of the coal gasifier.

  13. Oxidation resistant coatings for ceramic matrix composite components

    Energy Technology Data Exchange (ETDEWEB)

    Vaubert, V.M.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Hirschfeld, D.A. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Materials and Metallurgical Engineering

    1998-11-01

    Corrosion resistant Ca{sub 0.6}Mg{sub 0.4}Zr{sub 4}(PO{sub 4}){sub 6} (CMZP) and Ca{sub 0.5}Sr{sub 0.5}Zr{sub 4}(PO{sub 4}){sub 6} (CS-50) coatings for fiber-reinforced SiC-matrix composite heat exchanger tubes have been developed. Aqueous slurries of both oxides were prepared with high solids loading. One coating process consisted of dipping the samples in a slip. A tape casting process has also been created that produced relatively thin and dense coatings covering a large area. A processing technique was developed, utilizing a pre-sintering step, which produced coatings with minimal cracking.

  14. Resistance Spot Weldability of Galvanize Coated and Uncoated TRIP Steels

    Directory of Open Access Journals (Sweden)

    Hayriye Ertek Emre

    2016-11-01

    Full Text Available In this study, the resistance spot weldabilty of zinc galvanize-coated and uncoated TRIP800 steels was investigated in detail. Depending on the welding parameters such as welding current and welding time, the effects of zinc coating on the weld nugget geometry, the tensile shear strength, the failure modes, the hardness, and the microstructure of the resistance spot-welded sample were studied, and the results are compared with that of uncoated weldment. The coating on the surface of the TRIP steel causes a decrease in the weld nugget size and tensile shear strength of the weldment, and it changes to failure mode of the test sample from pullout to interfacial or partial interfacial fracture. As compared with the uncoated sample, the galvanized TRIP800 steel weldment has required a larger critical nugget size for achieving the desired pullout fracture mode and acceptable tensile shear strength.

  15. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we coated coupons of selected alloy steels with diffusion coatings of Cr and Al, as well as with titanium and tantalum nitrides. The coated samples were analyzed for their surface composition. In several instances, the samples were also cut to determine the depth profile of the coating. Several of the early runs did not yield uniform or deep enough coatings and hence a significant portion of the effort in this period was devoted fixing the problems with our fluidized bed reactor. Before the end of the quarter we had prepared a number of samples, many of them in duplicates, and sent one set to Wabash River Energy Laboratory for them to install in their gasifier. The gasifier was undergoing a scheduled maintenance and thus presented an opportunity to place some of our coupons in the stream of an operating gasifier. The samples submitted included coated and uncoated pairs of different alloys.

  16. The abrasion and impact-abrasion behavior of austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Dogan, Omer N.; Lerner, Y.S. (University of Northern Iowa)

    1998-01-01

    Austempering of ductile irons has led to a new class of irons, Austempered Ductile Irons (ADIs), with improved mechanical strength and fracture toughness lacking in gray cast irons. Laboratory wear tests have been used to evaluate the abrasive and impact-abrasive wear behavior of a suite of ADIs. The use of high-stress, two-body abrasion, low-stress, three-body abrasion, and impact-abrasion tests provides a clear picture of the abrasive wear behavior of the ADIs and the mechanisms of material removal. When combined with hardness measurements, fracture toughness and a knowledge of the microstructure of the ADIs, the overall performance can be assessed relative to more wear resistant materials such as martensitic steels and high-chromium white cast irons

  17. 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.

  18. Structure and Properties Characterization of Ceramic Coatings Produced on Steel Using a Combined Technique

    Institute of Scientific and Technical Information of China (English)

    SHENDe-jiu; WANGYu-lin; GUWei-chao; XINGGuang-zhong

    2004-01-01

    Metallurgically bonded ceramic coatings were prepared on a steel surface with a combined method of arc spraying and micro-arc oxidation for the first time. Coatings were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Point and line distribution of elements of the ceramic coatings were determined using energy dispersive spectroscopy (EDS). Coatings abrasive wear resistance, corrosion resistance and hot impact property were assessed respectively. The property test results show that metallurgically bonded ceramic coatings were formed on aluminum coatings and the ceramic coatings is mainly composed of α-Al2O3, γ-Al2O3, θ-Al2O3 and a little amorphous. The coatings possess excellent abrasive wear, corrosion and hot shock resistance, which can in part be attributed to the gradual distribution of different phases from surface to the substrate.

  19. Fouling-resistant polymer brush coatings

    KAUST Repository

    Thérien-Aubin, Héloïse

    2011-11-01

    A major problem to be addressed with thin composite films used in processes such as coatings or water purification is the biofouling of the surface. To address this problem in a model system, functionalized polyaramide membranes containing an atom transfer radical polymerization (ATRP) initiator were synthesized as a versatile approach to easily modify the surface properties of the polyaramide. Poly(methacrylic acid) brushes were grown using surface initiated ATRP followed by the functionalization of the poly(methacrylic acid) brushes with different side-chains chosen to reduce adhesion between the membrane and foulant. The relation between membrane fouling and the physicochemical properties of the surface was investigated in detail. © 2011 Elsevier Ltd. All rights reserved.

  20. Examining properties of arc sprayed nanostructured coatings

    Directory of Open Access Journals (Sweden)

    A. Czupryński

    2016-04-01

    Full Text Available The article presents the results of examining properties of arc sprayed coating obtained with nano-alloy on the iron matrix with a high amount of fine carbide precipitates sprayed on non-alloyed steel plates intended for high temperature operation. Powder metal cored wire EnDOtec DO*390N 1,6 mm diameter, was used to produce, dense, very high abrasion and erosion resistant coatings approx. 1,0 mm thick. Nano-material coatings characterization was done to determine abrasion resistance, erosion resistance, adhesion strength, hardness as well as metallographic examinations. Results have proved high properties of arc sprayed nano-material coatings and have shown promising industrial applications.

  1. Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

    Energy Technology Data Exchange (ETDEWEB)

    Amir, N., E-mail: norlailiamir@petronas.com.my; Othman, W. M. S. W., E-mail: wamosa@gmail.com; Ahmad, F., E-mail: faizahmad@petronas.com.my [Mechanical Engineering Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

  2. Brief Introduction to the Development of Fire-resistant Coating%浅谈防火涂料的发展应用

    Institute of Scientific and Technical Information of China (English)

    陆明

    2011-01-01

    归纳了防火涂料的发展历程,重点介绍了我国防火涂料的应用现状,分别介绍了钢结构防火涂料、电缆防火涂料在我国的应用和我国新型阻燃剂的研发现状,初步提出了更环保的具有更好耐水性、耐酸性、耐碱性、耐磨性、阻燃性的膨胀型非有机溶剂防火涂料的发展应用前景。%The development process of fire-resistant coating was described.Focusing on the present situation of the application of fire-retardant in China,the development and application prospect for the organic solvent type expansion of fire-resistant coating were put forward.The development and application aspects of a more environmentally friendly fire retardant coating of non-organic solvent with better water resistance,acid resistance,alkali resistance,abrasion resistance,and flame retardant intumescent were initially proposed.

  3. Study on Abrasive Wear Properties of MoB/CoCr Cermet Coating%MoB/CoCr金属陶瓷涂层的磨粒磨损性能研究

    Institute of Scientific and Technical Information of China (English)

    陈枭; 纪岗昌

    2012-01-01

    在310S基体表面采用低压等离子喷涂(LPPS)技术制备MoB/CoCr金属陶瓷涂层.用扫描电镜观察涂层的组织结构:测试了MoB/CoCr涂层的显微硬度和结合强度;用湿式橡胶轮磨粒磨损试验机测试涂层的磨损性能.结果显示:MoB/CoCr涂层组织为层状结构,涂层与310S基体之间、表面涂层与过渡涂层之间结合良好.MoB/CoCr涂层具有较高的硬度值和结合强度,且具有良好的抗磨粒磨损性能.%MoB/CoCr cermet coating was deposited by low pressure plasma spraying (LPPS) on 310S steel. The microstructure of the MoB/CoCr coating was observed by SEM. The microhardness and bonding strength of the MoB/CoCr coating were tested. The abrasive wear properties were evaluated by wet sand rubber wheel tester. The results show that MoB/CoCr coating is dense and has excellent combination with 310S steel substrate. MoB/CoCr coating has high hardness and excellent wear properties.

  4. Deposition and properties of high-velocity-oxygen-fuel and plasma-sprayed Mo-Mo2C composite coatings

    Science.gov (United States)

    Prchlik, L.; Gutleber, J.; Sampath, S.

    2001-12-01

    Molybdenum thermal-spray coatings, dispersion strengthened by molybdenum oxides and molybdenum carbides, play an important role in industrial tribological applications. Traditionally, they have been prepared by plasma and wire flame spraying. High porosity and lower cohesion strength limit their application in situations where both galling and abrasion wear is involved. In this study, high-velocity-oxygen-fuel (HVOF) deposition of molybdenum and molybdenum carbide coatings was attempted. Deposition was achieved for all powders used. Composition, microstructure, mechanical, and wear properties of the HVOF synthesized coatings were evaluated and compared with plasma-sprayed counterparts. The HVOF coatings possessed a very good abrasion resistance, whereas plasma deposits performed better in dry sliding tests. Measurements showed a close relationship between the coating surface hardness and its abrasion resistance. Results also suggested correlation between molybdenum carbide distribution in the molybdenum matrix and the sliding friction response of Mo-Mo2C coatings.

  5. Tropical Weather Resistant Galvanized Steel Coated and Uncoated

    Directory of Open Access Journals (Sweden)

    Suárez-Corrales Xenia Isbel

    2014-01-01

    Full Text Available The corrosion behavior of coated and uncoated galvanized steel products is determined by exposing them to accelerated and natural climatic test. Accelerated tests were carried out in climatic chambers and natural atmospheric test in a marine-coastal station (Cojimar. The influence of tropical humid climate on these products is determined. Adhesion is an important property for a good performance, from the decorative point of view or as an additional protection. The evaluation indicates that 95% of the galvanized steel products show a good corrosion resistance; although 71% of coated galvanized products and 100% of painted galvanized products do not cover the requirements with respect to the mechanical and corrosion protection aspects. For a good efficiency and economic performance of metal mechanical industry, a correct surface treatment and coating application is required. A key point is to increase the quality by improving a better corrosion protective performance respecting uncoated galvanized steel.

  6. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-03-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we conducted two exposure tests with coated and uncoated coupons. The first one was aborted after a short period, because of a leak in the pressure regulator of a CO/CO{sub 2}/H{sub 2} gas mixture gas cylinder that was used to prepare the simulated coal gas stream. Nevertheless, this run was very instructive as it showed that during the brief exposure when the concentration of H{sub 2}S increased to 8.6%, even specialty alloys such as HR160 and I800 were badly corroded, yet the sample of a SS405-steel that was coated with Ti/Ta showed no signs of corrosion. After replacing the pressure regulator, a second run was conducted with a fresh set of coated and uncoated samples. The Ti/Ta-coated on to SS405 steel from the earlier runs was also exposed in this test. The run proceeded smoothly, and at the end of test the uncoated steels were badly damaged, some evidence of corrosion was found on coupons of HR160 and I800 alloys and the Cr-coated steels, but again, the Ti/Ta-coated sample appeared unaffected.

  7. Study on the influent factors of magnesium phosphate cement repair materials abrasion resistance%磷酸镁水泥修补材料耐磨性影响因素研究∗

    Institute of Scientific and Technical Information of China (English)

    汪宏涛; 张时豪; 丁建华; 齐召庆

    2015-01-01

    以重烧 Mg O 和磷酸二氢铵为主要原料制备磷酸镁水泥修补材料,研究了氧化镁与磷酸二氢铵的比值(M/P)、水胶比(W/B)、硼砂掺量、粉煤灰掺量及龄期对磷酸镁水泥石耐磨性的影响,采用 X射线衍射分析和扫描电镜探讨不同龄期水化产物的物相组成及结构。结果表明,M/P=4时磷酸镁水泥石耐磨性最强;7d内磷酸镁水泥石耐磨性随W/B增大而减弱;掺入硼砂和粉煤灰都会影响磷酸镁水泥石的耐磨性,且掺量越大耐磨性越差;磷酸镁水泥石耐磨性随龄期延长而提升。%Based on the magnesium oxide and ammonium dihydrogen phosphate as the main raw material prepa-ration of magnesium phosphate cement.the influent law of different M/P ratio (quality ratio of magnesium and potassium dihydrogen phosphate),the ratio of water and binder (W/B ratio),borax content,dosage of fly ash and ages on the magnesium phosphate cement abrasion resistance are studied in this passage.XRD and SEM are used to investigate the phase composition and structure of the hydration products in different ages.The results show that the magnesium phosphate cement has the strongest abrasion resistance when M/P=4;within 7 days the abrasion resistance decreases when W/B increases;borax content and fly ash can weaken the abrasion resist-ance of magnesium phosphate cement,and the more the dosage,the worse the abrasion resistance;the abrasion resistance of magnesium phosphate cement increases with the age.

  8. Preparation of Conductive Coating Solutions by Blending Waterborne Acrylic Polyurethane Dispersion with Carbon Nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Woo Young; Yun, Dong Gu; Song, Ki Chang [Konyang University, Nonsan (Korea, Republic of)

    2013-02-15

    Waterborne polyurethane dispersion (WPUD) was synthesized from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with an acrylate monomer, methyl methacrylate (MMA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. With increasing the amount of MMA in the AUD, the pencil hardness, abrasion resistance and chemical resistance of the coating films were improved, but the electrical conductivity of the coating films was decreased. On the other hand, the pencil hardness, abrasion resistance and chemical resistance of coating films were decreased, but the electrical conductivity was enhanced with increasing the amount of MWCNT in the conductive coating solutions.

  9. [Dependence of the dentinal abrasion of human teeth on their microhardness].

    Science.gov (United States)

    Remizov, S M; Pruzhanskiĭ, L Iu

    1989-01-01

    The dentin resistance against abrasion was studied as related to its microhardness. Sections of 15 intact teeth were investigated (central upper incisors). Water suspensions (40% weight-to weight) of dicalcium phosphate (DCP, FRG; and DKF-1 and DKF-2, USSR) were used as abrasives. Dentin microhardness was measured with a PMT-3 device, and abrasion assessed with profilographic technique. Dentin abrasion was related to its microhardness and to the kind of abrasive used. Dentin abrasion increased as its microhardness decreased. DCF showed minimal abrasive effect, DKF-2 had maximal effect with DKF-1 keeping the intermediate position.

  10. Falling sand tests on various coatings

    Energy Technology Data Exchange (ETDEWEB)

    Manetti, M.; Zonfrillo, G.; Pratesi, F. [Florence Univ. (Italy). Dipt. di Meccanica e Tecnologie Industriali; Giovannetti, I. [GE Oil and Gas - Nuovo Pilnone, Florence (Italy)

    2010-07-01

    Abrasive wear is responsible for severe machine parts and in particular of compressor impellers. Methods of increasing service lifetime are based on employment of abrasion resistant materials or more frequently of the creation of hard, wear-resistant surface layers. In this work a bare aluminium alloy and the same alloy with four different coatings have been tested at room temperature, in order to verify their resistance to falling abrasive. Following standard ASTM D968-93, tests have been performed using a precise quantity of sand as abrasive and letting it fall on the sample with a standard apparatus: two different kinds of sand have been used, in order to obtain also information on the influence of composition and Grain size of the abrasive on material resistance. Determinations of hardness, roughness, weight loss, and morphology of the eroded surface have also been carried out. The comparison between the coatings in vestilated has been performed on the basis of the thickness decrease of the samples. (orig.)

  11. Environmentally Resistant Mo-Si-B-Based Coatings

    Science.gov (United States)

    Perepezko, J. H.; Sossaman, T. A.; Taylor, M.

    2017-06-01

    High-temperature applications have demonstrated aluminide-coated nickel-base superalloys to be remarkably effective, but are reaching their service limit. Alternate materials such as refractory (e.g., W, Mo) silicide alloys and SiC composites are being considered to extend high temperature capability, but the silica surfaces on these materials require coatings for enhanced environmental resistance. This can be accomplished with a Mo-Si-B-based coating that is deposited by a spray deposition of Mo followed by a chemical vapor deposition of Si and B by pack cementation to develop an aluminoborosilica surface. Oxidation of the as-deposited (Si + B)-pack coatings proceeds with partial consumption of the initial MoSi2 forming amorphous silica. This Si depletion leads to formation of a B-saturated Mo5Si3 (T1) phase. Reactions between the Mo and the B rich phases develop an underlying Mo5SiB2 (T2) layer. The T1 phase saturated with B has robust oxidation resistance, and the Si depletion is prevented by the underlying diffusion barrier (T2). Further, due to the natural phase transformation characteristics of the Mo-Si-B system, cracks or scratches to the outer silica and T1 layers can be repaired from the Si and B reservoirs of T2 + MoB layer to yield a self-healing characteristic. Mo-Si-B-based coatings demonstrate robust performance up to at least 1700 °C not only to the rigors of elevated temperature oxidation, but also to CMAS attack, hot corrosion attack, water vapor and thermal cycling.

  12. Effect of coating density on oxidation resistance and Cr vaporization from solid oxide fuel cell interconnects

    DEFF Research Database (Denmark)

    Talic, Belma; Falk-Windisch, Hannes; Venkatachalam, Vinothini

    2017-01-01

    •Protective action of dense and porous spinel coatings on Crofer 22 APU was compared. •Reduction and re-oxidation produces denser coatings than heat treating in air only. •Coating density has minor influence on oxidation resistance at 800 °C in air. •Dense coating resulted in three times lower Cr...

  13. Pipeline coating comparison methods for northern pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Singh, P. [Shaw Pipe Protection, Calgary, AB (Canada); Purves, G.A. [Cimarron Engineering Ltd., Calgary, AB (Canada)

    2004-07-01

    Two high-quality pipe coatings designed for northern environments were compared for their relative costs and suitability for the conditions that will be encountered in the field. Coating selection should consider local conditions to achieve the optimum life-cycle costs for the system. Some of the key factors affecting the integrity of the protective coating on a pipe include the effects of cold temperature and soil types. In this study, both Fusion Bonded Epoxy (FBE) and High Performance Composite Coatings (HPCC) were evaluated for an entire pipeline installation in a northern environment, from the coating plant to the pipe trench. The evaluation focused on the advantages of better abrasion resistance of the HPCC coating. This was compared against the incremental cost of HPCC coating over FBE on large diameter NPS 30 to NPS 48 pipelines. The following parameters influenced the choice of coating: storage, transportation and handling; bending ability under cold weather conditions; pipe installation and backfilling; weld joint coatings; coating repair and cathodic protection and pipeline integrity. Some of the construction costs that are indirectly affected by the choice of pipe coating include right-of-way preparation and restoration; trenching; supervision, service and downtime and specialist crossings. It was concluded that HPCC has better resistance to abrasion than FBE and is more flexible in extremely cold temperatures. Standard FBE is about 10 per cent less expensive than HPCC. In general HPCC will require less coating protection than FBE, depending on site conditions. 3 refs., 18 tabs., 8 figs.

  14. Anti-reflective and anti-soiling coatings with self-cleaning properties

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Vinod; Brophy, Brenor L.

    2016-10-04

    Disclosed herein is a coated glass element including a glass component and a coating adhered to the glass component through siloxane linkages, the coating having at least one of an anti-reflective property, a high abrasion resistance property and a hydrophobic property, wherein the coating comprises a dried gel formed from at least one hydrolyzed alkoxysilane-based sol and at least one hydrolyzed organosilane-based sol.

  15. Diffusion Coatings for Corrosion Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve its resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we focused on getting a bench-scale test system to expose alloy coupons to simulated gasifier environment. The test facility was designed to allow about 20 specimen coupons to be exposed simultaneously for an extend period to a simulated coal gas stream at temperatures up to 1000 C. The simulated gas stream contained about 26%H{sub 2}, 39%CO, 17%CO{sub 2}, 1.4% H{sub 2}S and balance steam. We successfully ran a 100+h test with coated and uncoated stainless steel coupons. The tested alloys include SS304, SS316, SS405, SS409, SS410, and IN800. The main finding is that Ti/Ta coating provides excellent protection to SS405 under conditions where uncoated austenitic and ferritic stainless steel alloy coupons are badly corroded. Cr coatings also appear to afford some protection against corrosion.

  16. Corrosion resistance of zinc-magnesium coated steel

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, N.C. [Ford Motor Company Ltd., Dunton Engineering Centre, Room GB15/GM-D01, Laindon, Basildon, Essex SS15 6EE (United Kingdom) and School of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)]. E-mail: niamh.hosking@gmail.com; Stroem, M.A. [Volvo Car Corporation, Building VCPC, Maildrop PV 1B, Volvo Jacobs vag, Goeteborg SE-405 31 (Sweden); Shipway, P.H. [School of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Rudd, C.D. [School of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2007-09-15

    A significant body of work exists in the literature concerning the corrosion behaviour of zinc-magnesium coated steel (ZMG), describing its enhanced corrosion resistance when compared to conventional zinc-coated steel. This paper begins with a review of the literature and identifies key themes in the reported mechanisms for the attractive properties of this material. This is followed by an experimental programme where ZMG was subjected to an automotive laboratory corrosion test using acidified NaCl solution. A 3-fold increase in time to red rust compared to conventional zinc coatings was measured. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the corrosion products formed. The corrosion products detected on ZMG included simonkolleite (Zn{sub 5}Cl{sub 2}(OH){sub 8} . H{sub 2}O), possibly modified by magnesium uptake, magnesium hydroxide (Mg(OH){sub 2}) and a hydroxy carbonate species. It is proposed that the oxygen reduction activity at the (zinc) cathodes is reduced by precipitation of alkali-resistant Mg(OH){sub 2}, which is gradually converted to more soluble hydroxy carbonates by uptake of atmospheric carbon dioxide. This lowers the surface pH sufficiently to allow thermodynamically for general precipitation of insoluble simonkolleite over the corroding surface thereby retarding the overall corrosion reactions, leaving only small traces of magnesium corrosion products behind. Such a mechanism is consistent with the experimental findings reported in the literature.

  17. 回火温度对高锰钢耐磨性能的影响%The Effect of Tempering Temperature on the Abrasion Resistance of High Manganese Steel

    Institute of Scientific and Technical Information of China (English)

    熊玉竹; 杜建平; 伍玉娇

    2001-01-01

    为进一步研究动态应变时效(DSA)强化在高锰钢的加工硬化过程中对其耐磨性能的影响,将合金高锰钢和普通高锰钢进行不同温度的回火处理,并对其组织、结构、电阻及耐磨性能进行分析。结果发现合金高锰钢中的强碳化物形成元素Cr有效地扩大了C-Mn有序原子对团簇微区,且这些有序的原子对团簇微区对提高高锰钢的耐磨性能有重要作用。%In order to further study how the strengthening of the dynamic strain aging(DSA) affects the abrasion resistance of high manganese steel,alloyed high manganese steel and high manganese steel are tempered at different temperatures.By analyzing their structure,resistance and abrasion resistance,it is concluded that the carbonide-formed Cr in alloyed high manganese steel can effectively enlarge the C-Mn micro-regions of the regular automic couples which have an important effect on the increase in abrasion resistance of alloyed high manganese steel.

  18. Microstructure and corrosion resistance of phytic acid conversion coatings for magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cui Xiufang [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li Qingfen [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Li Ying; Wang Fuhui [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Jin Guo [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)], E-mail: jg97721@yahoo.com.cn; Ding Minghui [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2008-12-30

    In this paper, a new innoxious and pollution-free chemical protective coating for magnesium alloys, phytic acid conversion coating, was prepared. The conversion coatings are found to have high cover ratio and no cracks are found by atomic force microscopes (AFM) and scanning electron microscopy (SEM). The main elements of the conversion coatings are Mg, Al, O, P and C by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The chemical state of the elements in the coatings was also investigated by Fourier transform infrared spectroscopy (FTIR). AES depth profile analysis suggests that the thickness of the conversion coating is about 340 nm. The corrosion resistance of the coatings was evaluated by polarization curves. The results indicate that the corrosion resistance for the conversion coated AZ91D magnesium alloys in 3.5% NaCl solution increases markedly. The mechanisms of corrosion resistance and coatings formation are also discussed.

  19. Microstructure and corrosion resistance of phytic acid conversion coatings for magnesium alloy

    Science.gov (United States)

    Cui, Xiufang; Li, Qingfen; Li, Ying; Wang, Fuhui; Jin, Guo; Ding, Minghui

    2008-12-01

    In this paper, a new innoxious and pollution-free chemical protective coating for magnesium alloys, phytic acid conversion coating, was prepared. The conversion coatings are found to have high cover ratio and no cracks are found by atomic force microscopes (AFM) and scanning electron microscopy (SEM). The main elements of the conversion coatings are Mg, Al, O, P and C by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The chemical state of the elements in the coatings was also investigated by Fourier transform infrared spectroscopy (FTIR). AES depth profile analysis suggests that the thickness of the conversion coating is about 340 nm. The corrosion resistance of the coatings was evaluated by polarization curves. The results indicate that the corrosion resistance for the conversion coated AZ91D magnesium alloys in 3.5% NaCl solution increases markedly. The mechanisms of corrosion resistance and coatings formation are also discussed.

  20. White primer permits a corrosion-resistant coating of minimum weight

    Science.gov (United States)

    Albrecht, R. H.; Jensen, D. P.; Schnake, P.

    1966-01-01

    White primer for coating 2219 aluminum alloy supplies a base for a top coating of enamel. A formulation of pigments and vehicle results in a primer with high corrosion resistance and minimum film thickness.

  1. Rare earth effect on the microstructure and wear resistance of Ni-based coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhenyu [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)], E-mail: zhangzhenyu@mail.tsinghua.edu.cn; Lu Xinchun [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Han Baolei [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Luo Jianbin [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2007-04-25

    Eight different Cr{sub 3}C{sub 2}-NiCr coatings doped with rare earth oxide were deposited with supersonic plasma spraying. Surface contact profiler, X-ray diffractometer, environmental scanning electron microscopy, multi-functional tribometer, microhardness tester were employed to investigate the microstructure and friction and wear performance of sprayed coatings. The results show that the wear volume loss of coatings doped with 2 wt.% La{sub 2}O{sub 3} and 2 wt% La{sub 2}O{sub 3} + 2wt.% CeO{sub 2} is three orders of magnitude smaller than that of the coating without rare earth, respectively, correspondingly the friction coefficient of two coatings is only two third of that of the coating without rare earth. According to the SEM worn surface observations, the wear mechanism of the coating doped with 2 wt% La{sub 2}O{sub 3} is strain crushed wear induced by plastic deformation and fatigue during the sliding process, which is distinct with abrasive wear and delamination fracture wear mechanisms of the coating without rare earth. Furthermore, rare earth can make the microstructure more compact, less porous and denser, leading to the increase of average microhardness and decrease of its fluctuation range of sprayed coatings.

  2. Low conductivity and sintering-resistant thermal barrier coatings

    Science.gov (United States)

    Zhu, Dongming (Inventor); Miller, Robert A. (Inventor)

    2007-01-01

    A thermal barrier coating composition is provided. The composition has a base oxide, a primary stabilizer, and at least two additional cationic oxide dopants. Preferably, a pair of group A and group B defect cluster-promoting oxides is used in conjunction with the base and primary stabilizer oxides. The new thermal barrier coating is found to have significantly lower thermal conductivity and better sintering resistance. In preferred embodiments, the base oxide is selected from zirconia and hafnia. The group A and group B cluster-promoting oxide dopants preferably are selected such that the group A dopant has a smaller cationic radius than the primary stabilizer oxide, and so that the primary stabilizer oxide has a small cationic radius than that of the group B dopant.

  3. Wear and corrosion resistance of laser remelted and plasma sprayed Ni and Cr coatings on copper

    Institute of Scientific and Technical Information of China (English)

    梁工英; 黄俊达; 安耿

    2004-01-01

    Nickel and chromium coatings were produced on the copper sheet using plasma spraying and laser remelting. The sliding wear test was achieved on a block-on-ring tester and the corrosion test was carried out in an acidic atmosphere. The corrosive behaviors of both coatings and original copper samples were investigated by using an impedance comparison method. The experimental results show that the nickel and chromium coatings display better wear resistance and corrosion resistance relative to the original pure copper sample. The wear resistance of the coatings is 8 - 12 times as large as original samples, and the wear resistance of laser remelted samples is better than that of plasma sprayed ones. The corrosion resistance of laser remelted nickel and chromium samples is better than that of plasma sprayed samples respectively. The corrosion rate of chromium coatings is less than that of nickel coatings, and the laser remelted Cr coating exhibits the least corrosion rate.

  4. Preparation and corrosion resistance of MAO/Ni-P composite coat on Mg alloy

    Science.gov (United States)

    Fan, Xizhi; Wang, Ying; Zou, Binglin; Gu, Lijian; Huang, Wenzhi; Cao, Xueqiang

    2013-07-01

    Microarc oxidation (MAO) coat was designed as an intermediate layer for the electroless plated Ni-P top coat, providing inert surface and necessary hardness for Mg alloy substrate. The composite coat was successfully prepared to improve the corrosion resistance of Mg alloy. The preparation and the characterization of the composite coat were investigated. The results show that the pre-treatment of MAO before electroless plating plays an important role in the deposition of compact composite coat. The activation (by HF solution) makes the MAO coat dense with uniform cracks which supply excellent bonding interface for Ni-P coat. Compared with monolithic MAO or Ni-P coat, the composite coat has excellent corrosion resistance and stable bonding interface. There is main pit corrosion at substrate after the corrosive medium penetrating through the whole coat. With the inert MAO interlayer, the electrochemical corrosion between the Ni-P and substrate is effectively inhibited.

  5. 再生骨料混凝土路面耐磨性的研究%Research on Abrasion Resistance of Recycled Aggregate Concrete by Response Surface Methodology

    Institute of Scientific and Technical Information of China (English)

    杨宁; 赵美霞

    2011-01-01

    采用单因素扫描法系统考察了再生粗骨料的取代率、水胶比、砂率、胶凝材料的总用量等因素对再生混凝土耐磨性能的影响,分析了其产生的原因.在单因素试验的基础上,通过响应面法对影响再生混凝土耐磨性能的显著因素进行了更进一步的研究,并建立了相应的预测模型.结果表明:再生骨料的取代率和水胶比对再生混凝土耐磨性影响最为显著,砂率和胶凝材料的总用量对再生混凝土耐磨性有一定的影响,且再生骨料取代率为43%、水胶比为0.38、砂率为35%时再生混凝土耐磨性能最佳,研究结果为再生混凝土耐磨性的深入研究提供了一定的借鉴和参考.%The single factor scanning method was used to analyze the effects of replacement ratio of recycled coarse aggregate, water-binder ratio, sand-coarse aggregate ratio, the total amount of gelled material on the wear resistance of recycled aggregate concrete, and its reasons were analyzed. On the basis of the single-factor test, the significant influence factors of the wear resistance of recycled aggregate concrete were further studied by the response surface methodology ( RSM ) , and a correlation model on the optimized wear resistance of recycled aggregate concrete was presented. The analysis results show that replacement ratio of recycled coarse aggregate, water-binder ratio exert tremendous influence on wear resistance of recycled aggregate concrete, sand-coarse aggregate ratio and the total amount of gelled material exert certain influence. Wear resistance of recycled aggregate concrete is best when replacement ratio of recycled coarse aggregate is 43% , water-binder ratio is 0. 38, sand-coarse aggregate ratio is 0. 35. The test results also can provide a reference for future further study on abrasion resistance of recycled aggregate concrete.

  6. 磁力磨削Al2 O3-TiO2陶瓷涂层试验%Experimental Research on Magnetic Abrasive Finishing Ceramic Coating with Al2 O3-TiO2

    Institute of Scientific and Technical Information of China (English)

    焦龙飞; 高国富

    2016-01-01

    采用磁力研磨技术进行Al2 O3-TiO2陶瓷涂层的精密加工,设计了平面陶瓷研磨的试验装置,通过研究磨粒粒度等参数对表面粗糙度的影响规律,得出精密加工的最优参数。%The precision machining technology of ceramic coating with coating ceramic are discussed.The experimen-tal setup of magnetic abrasive finishing (MAF)was developed to study the mechanism and characteristics of finishing ce-ramic coating with Al2 O3-TiO2 .A magnetic field of the experimental device is provided by permanent magnet.The influence of machining parameters on the finished surface roughness was discussed and the optimal parameter of the precision machi-ning was obtained.

  7. Scratch resistance of SiO{sub 2} and SiO{sub 2} - ZrO{sub 2} sol-gel coatings on glass-ceramic obtained by sintering; Resistencia al desgaste de recubrimientos sol-gel de SiO{sub 2} y SiO{sub 2} - ZrO{sub 2} sobre materiales vitroceramicos obtenidos por sinterizacion

    Energy Technology Data Exchange (ETDEWEB)

    Soares, V. O.; Soares, P.; Peitl, O.; Zanotto, E. D.; Duran, A.; Castro, Y.

    2013-10-01

    The sol-gel process is widely used to obtain coatings on glass-ceramic substrates in order to improve the scratch and abrasion resistance, also providing a bright and homogeneous appearance of a glaze avoiding expensive final polishing treatments. This paper describes the preparation of silica and silica / zirconia coatings by sol-gel method on Li{sub 2}O-Al{sub 2}O3-SiO{sub 2} (LAS) glassceramic substrates produced by sintering. The coatings were deposited by dip-coating on LAS substrates and characterized by optical microscopy and spectral ellipsometry. On the other hand, hardness and elastic modulus, coefficient of friction and abrasion and scratch resistance of the coatings were determined and compared with the substrate properties. Coatings deposited on LAS glass-ceramic confere the substrate a bright and homogeneous aspect, similar to a glaze, improving the appearance and avoiding the final polishing. However these coatings do not increase the scratch resistance of the substrate only equaling the properties of the glass-ceramic. (Author)

  8. High-temperature corrosion resistance of ceramics and ceramic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.

    1996-06-01

    Ceramics and ceramic composites offer the potential to operate fossil energy systems at the higher temperatures necessary for improved energy efficiency and better environmental control. However, because many fossil fuel-derived processes contain sulfur, chlorine, and carbon, as well as oxygen, degradation from high-temperature corrosion and environmental effects arising from reactions of solids with gases and condensable products is a common life-determining factor in operating systems. Ceramic-based products are not immune to such degradation; adequate corrosion resistance must be assured to exploit the technical and economic potential of such materials. This is normally accomplished by using stable, sound oxides that exist in their bulk form, that naturally grow as surface layers upon exposure to an oxidizing environment, or that are deposited as a coating on a susceptible material. It is therefore important to examine the critical issues with respect to more environmental stability of ceramics that have the potential to be corrosion resistant in particular fossil environments. Key aspects include not only chemical compatibility, but the influence of the environment on the mechanical behavior of the ceramic materials. In addition, for coatings, the mechanical reliability of the ceramic is a key issue in that an otherwise corrosion-resistant surface layer must remain sound and adherent in order to provide protection to the underlying substrate. The purpose of this work is to support the development of advanced ceramics and ceramic composites for applications in fossil environments by examining critical issues related to high-temperature corrosion resistance. More specifically, the overall objective of this task is to examine the chemical compatibility and reliability of potentially corrosion-resistant ceramics being developed as protective overcoats and/or structural materials as parts of other work elements funded by the AR&TD Program.

  9. Fe–0.4 wt.%C–6.5 wt.%Cr hardfacing coating: Microstructures and wear resistance with La{sub 2}O{sub 3} additive

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xiaoru [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhao, Bin [Jiangsu Xuzhou Construction Machinery Research Institute, Xuzhou 221004 (China); Yang, Jian; Xing, Xiaolei; Zhou, Yefei; Yang, Yulin [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Yang, Qingxiang, E-mail: qxyang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2014-10-30

    Highlights: • Fe–0.4 wt.%C–6.5 wt.%Cr hardfacing coatings with different La{sub 2}O{sub 3} additives were developed. • The grain size of the hardfacing coating decreases with the increase of the La{sub 2}O{sub 3} additives. • The unidirectional wear resistance of the hardfacing coating is increased with the increase of the La{sub 2}O{sub 3} additives. • The friction coefficient is decreased and the reciprocating wear resistance is increased with the increase of the La{sub 2}O{sub 3} additives. - Abstract: Flux-cored wires with different La{sub 2}O{sub 3} additives were developed. The microstructures of the hardfacing coatings were observed by optical microscopy (OM) and field emission scanning electron microscope (FESEM). The phase structures were determined by X-ray diffraction (XRD). The hardness, wear resistance and friction coefficient of the hardfacing coatings were measured by Rockwell hardness tester, unilateral abrasive belt wear testing machine and CETR reciprocating wear testing machine, respectively. At last, the worn morphologies of the hardfacing coatings were observed by FESEM. The results indicate that, the microstructures of the hardfacing coatings consist of needle-like martensite, high alloy matensite and retained austenite. With the increase of La{sub 2}O{sub 3} additive, the high alloy matensite dissolves in the matrix gradually and the amount of retained austenite is not changed basically after it is increased firstly. When La{sub 2}O{sub 3} addition is 0.70 wt.%, the grain size of the hardfacing coating is the smallest, which is 18 μm and the average hardness is the highest. Unidirectional abrasive belt wear test shows that the high alloy martensite can be as wear-resistance phase during the wear process of the hardfacing coatings. When the La{sub 2}O{sub 3} addition is 0.35 wt.%, the unidirectional wear resistance of the hardfacing coating is the highest. Reciprocating wear test shows that with the increase of the La{sub 2}O

  10. Cellulose acetate/hydroxyapatite/chitosan coatings for improved corrosion resistance and bioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhenyu; Qin, Jinli [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ma, Jun, E-mail: caltary@gmail.com [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Biomedical Engineering, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-04-01

    Cellulose acetate (CA) nanofibers were deposited on stainless steel plates by electrospinning technique. The composite of hydroxyapatite (HAP) nanoparticles and chitosan (CHI) was coated subsequently by dip-coating. The structure and morphology of the obtained coatings were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The stability of the coatings in physiological environment was studied using electrochemical polarization and impedance spectroscopy. The CA nanofibers were embedded in the HAP/CHI coating and the resulted composite film was densely packed and uniform on the substrate. The in vitro biomineralization study of the coated samples immersed in simulated body fluid (SBF) confirmed the formation ability of bone-like apatite layer on the surface of HAP-containing coatings. Furthermore, the coatings could provide corrosion resistance to the stainless steel substrate in SBF. The electrochemical results suggested that the incorporation of CA nanofibers could improve the corrosion resistance of the HAP/CHI coating. Thus, biocompatible CA/HAP/CHI coated metallic implants could be very useful in the long-term stability of the biomedical applications. - Highlights: • The composite coatings were prepared by electrospinning and dip-coating. • Good in vitro bioactivity of the CA/HAP/CHI coating was confirmed. • Electrochemical behaviors in SBF of the coatings have been studied. • The CA/HAP/CHI coating shows better resistance property than HAP/CHI.

  11. Deposition of wear-resistant steel surfaces by the plasma rotating electrode coating process

    Science.gov (United States)

    Kim, Michael Robert

    A high-deposition rate thermal spray method was investigated for the purpose of coating aluminum cylinder bores with a wear resistant surface. This method, the plasma rotating electrode coating system (PROTEC) utilized transferred-arc melting of a rapidly rotating consumable electrode to create a droplet stream via centrifugal atomization. A cylindrical substrate was placed around the rotating rod, in the flight path of the droplets, to deposit a coating onto the internal surface of the cylinder. Selected coatings of 1045 steel deposited by the PROTEC coating method exhibited lower wear loss in lubricated sliding than wire-arc sprayed carbon steel coatings and gray cast iron. Splat cohesion was shown to be a significant factor in the wear resistance of PROTEC coatings. The relationship between deposition enthalpy and cooling rate of the coating was found to have the greatest effect on coating microstructure, and the coating cohesion. The most rapidly solidified coatings showed inferior splat cohesion in comparison to coatings that cooled more slowly. The increase in splat cohesion with decreased cooling rate was accompanied by the formation of a directionally oriented coating microstructure, likely formed during cellular solidification of the coating. A model describing the thermal state of the deposition process was used to predict the deposition conditions that would result in a cellular structure, and the level of splat cohesion required to produce a wear resistant coating.

  12. Erosion resistance in metal - ceramic multilayer coatings for gas turbine compressor applications

    OpenAIRE

    1995-01-01

    The erosion resistance of 50 m metal-ceramic multilayer coatings has been investigated under impact conditions comparable to those in a gas turbine compressor cascade. lt was possible to improve upon the erosion resistance of Ti-6Al-4V by a significant margin. The influence of layer mechanical properties, layer thickness, ceramic content and coating process on erosion resistance has been studied over a range of impact conditions. The most suitable coating formula...

  13. Study and Applications of Dynamic Resistance Profiles During Resistance Spot Welding of Coated Hot-Stamping Steels

    Science.gov (United States)

    Ighodaro, Osayande Lord-Rufus; Biro, Elliot; Zhou, Y. Norman

    2017-02-01

    This work compares the role of press hardened steel coating type (Al-Si and GA) on resistance spot welding by analyzing the dynamic resistance curves measured during the weld cycles of the respective materials. It was seen that the dynamic resistance profiles for GA- and Al-Si-coated steels are similar. But the GA specimens exhibited higher resistance than Al-Si-coated specimens in the as-received condition, while the Al-Si-coated specimens exhibited higher resistance after hot stamping. From the early stages of the dynamic resistance profiles, data were obtained and applied for computing the values of components of resistances associated with the different coatings since each coating exhibits characteristic value at the early stages. The results revealed that at the start of the welding cycle, the resistance of the electrode/sheet interface was significantly higher than that of the faying surface or the bulk resistance regardless of whether the steel was Al-Si- or GA-coated. The possible uses of these resistance values in studying welding current requirement and electrode tip life were discussed.

  14. Ultrasonic magnetic abrasive finishing

    Institute of Scientific and Technical Information of China (English)

    LU Ya-ping; MA Ji; ZHANG Jun-qiang; WANG Long-shan

    2006-01-01

    Put forward a new kind of polishing method, ultrasonic magnetic abrasive finishing (UMAF), and studied its mechanism of improving polishing efficiency. By analyzing all kind of forces acting on single abrasive particle in the polishing process and calculating the size of the composition of forces, get the conclusion that UMAF will enhance the efficiency of the normal magnetic abrasive finishing(MAF) due to the ultrasonic vibration increases the cutting force and depth. At last the idea of designing the UMAF system based on numerical control milling machine is put forward which is convenient to setup and will accelerate the practical application of MAF.

  15. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Angel Sanjurjo

    2004-05-01

    Heat-exchangers, filters, turbines, and other components in integrated coal gasification combined cycle system must withstand demanding conditions of high temperatures and pressure differentials. Under the highly sulfiding conditions of the high temperature coal gas, the performance of components degrade significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. A review of the literature indicates that the corrosion reaction is the competition between oxidation and sulfidation reactions. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers.

  16. UV curable hard coatings on polyesters

    Science.gov (United States)

    Datashvili, Tea; Brostow, Witold; Kao, David

    2006-10-01

    UV curable, hard and transparent hybrid inorganic-organic coatings with covalent links between the inorganic and the organic networks were prepared using organically crosslinked heteropolysiloxanes based on the sol-gel process. The materials were applied onto polyester sheets and UV cured. The deposition was followed by a thermal treatment to improve mechanical properties of the coatings. High light transmission and the resulting thermophysical properties indicate the presence of a nanoscale hybrid composition. The coatings show excellent adhesion to polyesters even without using primers. Further mechanical characterization shows that the coatings provide high hardness and good abrasion resistance.

  17. Radiation Resistant Hybrid Lotus Effect Photoelectrocatalytic Self-Cleaning Anti-Contamination Coatings Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop radiation resistant hybrid Lotus Effect photoelectrocatalytic self-cleaning anti-contamination coatings for application to Lunar...

  18. Effect of temperature on structure and corrosion resistance for electroless NiWP coating

    Indian Academy of Sciences (India)

    M Q YU; Q QIAO; F YOU; C L LI; Y ZHAO; Z Z XIAO; H L LUO; Z F XU; KAZUHIRO MATSUGI; J K YU

    2016-04-01

    The effect of plating temperatures between 60 and 90$^{\\circ}$C on structure and corrosion resistance for electroless NiWP coatings on AZ91D magnesium alloy substrate was investigated. Results show that temperature has a significant influence on the surface morphology and corrosion resistance of the NiWP alloy coating. An increase in temperature will lead to an increase in coating thickness and form a more uniform and dense NiWP coatings. Moreover, cracks were observed by SEM in coating surface and interface at the plating temperature of 90$^{\\circ}$C. Coating corrosion resistance is highly dependent on temperature according to polarization curves. The optimum temperature isfound to be 80$^{\\circ}$C and the possible reasons of corrosion resistance for NiWP coating have been discussed.

  19. Aluminide protective coatings on high–temperature creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-10-01

    Full Text Available This paper presents the results of research on aluminide protective coatings manufactured on high–temperature creep resistant cast steel. The main purpose of these coatings is protection against the high temperature corrosion, especially at high carburizing potential atmosphere. Coatings were obtained on cast steel type G–XNiCrSi36–18 with the following methods: pack cementation, paste method, cast method and slurry cementation. The phase composition, thickness and morphology of coatings were determined. Coatings capacity of carbon diffusion inhibition and thermal shocks resistance of coatings were determined with different methods. It was found, that all of the coatings reduce carbon diffusion in different degree and all coatings liable to degradation in consequence cracking and oxidation. Coating life time is mainly dependent on morphology, phase composition and service condition (thermal shocks first of all.

  20. Ethanol-resistant polymeric film coatings for controlled drug delivery.

    Science.gov (United States)

    Rosiaux, Y; Muschert, S; Chokshi, R; Leclercq, B; Siepmann, F; Siepmann, J

    2013-07-10

    The sensitivity of controlled release dosage forms to the presence of ethanol in the gastro intestinal tract is critical, if the incorporated drug is potent and exhibits severe side effects. This is for instance the case for most opioid drugs. The co-ingestion of alcoholic beverages can lead to dose dumping and potentially fatal consequences. For these reasons the marketing of hydromorphone HCl extended release capsules (Palladone) was suspended. The aim of this study was to develop a novel type of controlled release film coatings, which are ethanol-resistant: even the presence of high ethanol concentrations in the surrounding bulk fluid (e.g., up to 40%) should not affect the resulting drug release kinetics. Interestingly, blends of ethylcellulose and medium or high viscosity guar gums provide such ethanol resistance. Theophylline release from pellets coated with the aqueous ethylcellulose dispersion Aquacoat® ECD 30 containing 10 or 15% medium and high viscosity guar gum was virtually unaffected by the addition of 40% ethanol to the release medium. Furthermore, drug release was shown to be long term stable from this type of dosage forms under ambient and stress conditions (without packaging material), upon appropriate curing.

  1. Development of wear resistant ceramic coatings for diesel engine components

    Energy Technology Data Exchange (ETDEWEB)

    Haselkorn, M.H. (Caterpillar, Inc., Peoria, IL (United States))

    1992-04-01

    Improved fuel economy and a reduction of emissions can be achieved by insulation of the combustion chamber components to reduce heat rejection. However, insulating the combustion chamber components will also increase the operating temperature of the piston ring/cylinder liner interface from approximately 150{degree}C to over 300{degree}C. Existing ring/liner materials can not withstand these higher operating temperatures and for this reason, new materials need to be developed for this critical tribological interface. The overall goal of this program is the development of piston ring/cylinder liner material pairs which would be able to provide the required friction and wear properties at these more severe operating conditions. More specifically, this program first selected, and then evaluated, potential d/wear resistant coatings which could be applied to either piston rings an or cylinder liners and provide, at 350{degree}C under lubricated conditions, coefficients of friction below 0.1 and wear rates of less than 25 {times} lO{sup {minus}6} mm/hour. The processes selected for applying the candidate wear resistant coatings to piston rings and/or cylinder liners were plasma spraying, chemical vapor, physical vapor and low temperature arc vapor deposition techniques as well as enameling techniques.

  2. Abrasive wear behaviour of as cast and austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Baydogan, M.; Koekden, M.U.; Cimenoglu, H. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Science Engineering Istanbul (Turkey)

    2000-07-01

    In this study, abrasive wear behaviour of as cast and austempered GGG 50 and GGG 80 quality ductile irons was investigated. In the as cast condition, GGG 50 and GGG 80 quality ductile irons were having ferritic and pearlitic matrix structures, respectively. Austempering at 250 C after austenitisation at 900 C for 100 minutes produced bainitic matrix structure in both of the investigated ductile irons. Abrasive wear tests performed by rubbing the as cast and austempered specimens on Al{sub 2}O{sub 3} abrasive bands, revealed that austempering treatment improves abrasion resistance about 10-70% depending on the abrasive particle size and composition of the base iron. In the as cast condition, pearlitic GGG 80 grade ductile iron, has higher wear resistance than ferritic GGG 50 grade ductile iron. In the austempered condition GGG 50 and GGG 80 grade ductile irons which have bainitic matrix structure, exhibit almost similar wear resistance. (orig.)

  3. The effects of the diamond-like carbon film on the abrasive resistance of dental bur%类金刚石膜在牙科车针表面的初步应用

    Institute of Scientific and Technical Information of China (English)

    李雅瑾; 韩建民; 张仁国; 葛春玲; 王兵

    2011-01-01

    Objective; To study the effect of the diamond-like carbon film ( DLC) on the abrasive resistance of dental bur. Methods; Unused new diamond burs. Tungsten steel resin grinding heads and low-speed carbon steel ball burs were divided into two groups respectively, those with DLC costing were used in test group, those without coating were used as the controls. For the diamond bur, an experienced dentist used the coating and non-coating diamond burs respectively to grind the extracted tooth under the standard of all-crown reduction. One bur was used to grind five teeth, the effects of the two groups were judged by the dentist subjective feeling. For the Tungsten steel resin grinding head, the time of breaking through the resin block under the same rotation speed and same load were compared for the coating and non-coating heads. For the carbon steel ball bur, the edge of the ball burs was examined under microscope with the magnification of 75 times after the bur prepared type I cavity in three extracted teeth. Results: The coating diamond burs were belter than the non-coating judged by the dentist subjective feeling. The time of breaking through the resin block of the Tungsten steel resin grinding head in coating group was less than that in non-coating group, The wear of low-speed ball bur in coating group was slighter than that in non-coating group. Conclusion: DLC can increase the cutting efficiency, decrease the wear, and extend the working life of the bur, especially for the Tungsten steel grinding head and low-speed carbon steel ball bur.%目的:通过类金刚石镀膜(DLC)的方法提高牙科车针的耐磨性.方法:选择临床常用3种类型新车针,每种车针选择同种型号若干支,一组非镀膜作为对照组,一组镀膜作为试验组.对于金刚砂车针:由1名临床经验丰富的医生,使用镀膜与未镀膜车针,按照全冠牙体预备要求磨除离体牙(同一名正畸患者拔除的同名牙),同一根车针磨除5颗离体牙,记

  4. Contact air abrasion.

    Science.gov (United States)

    Porth, R

    1999-05-01

    The advantages of contact air abrasion techniques are readily apparent. The first, of course, is the greatly increased ease of use. Working with contact also tends to speed the learning curve by giving the process a more natural dental feel. In addition, as one becomes familiar with working with a dust stream, the potential for misdirecting the air flow is decreased. The future use of air abrasion for deep decay removal will make this the treatment of choice for the next millennium.

  5. Blanch Resistant and Thermal Barrier NiAl Coating Systems for Advanced Copper Alloys

    Science.gov (United States)

    Raj, Sai V. (Inventor)

    2005-01-01

    A method of forming an environmental resistant thermal barrier coating on a copper alloy is disclosed. The steps include cleansing a surface of a copper alloy, depositing a bond coat on the cleansed surface of the copper alloy, depositing a NiAl top coat on the bond coat and consolidating the bond coat and the NiAl top coat to form the thermal barrier coating. The bond coat may be a nickel layer or a layer composed of at least one of copper and chromium-copper alloy and either the bond coat or the NiAl top coat or both may be deposited using a low pressure or vacuum plasma spray.

  6. One-step spray-coating process for the fabrication of colorful superhydrophobic coatings with excellent corrosion resistance.

    Science.gov (United States)

    Li, Jian; Wu, Runni; Jing, Zhijiao; Yan, Long; Zha, Fei; Lei, Ziqiang

    2015-10-06

    A simple method was used to generate colorful hydrophobic stearate particles via chemical reactions between inorganic salts and sodium stearate. Colored self-cleaning superhydrophobic coatings were prepared through a facile one-step spray-coating process by spraying the stearate particle suspensions onto stainless steel substrates. Furthermore, the colorful superhydrophobic coating maintains excellent chemical stability under both harsh acidic and alkaline circumstances. After being immersed in a 3.5 wt % NaCl aqueous solution for 1 month, the as-prepared coatings remained superhydrophobic; however, they lost their self-cleaning property with a sliding angle of about 46 ± 3°. The corrosion behavior of the superhydrophobic coatings on the Al substrate was characterized by the polarization curve and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion test results indicated that the superhydrophobic coatings possessed excellent corrosion resistance, which could supply efficient and long-term preservation for the bare Al substrate.

  7. Oxidation resistance of the nanostructured YSZ coating on the IN-738 superalloy

    Directory of Open Access Journals (Sweden)

    Ahmad Keyvani

    2014-12-01

    Full Text Available Conventional and nanostructured YSZ coatings were deposited on the IN-738 Ni super alloy by the atmospheric plasma spray technique. The oxidation was measured at 1100°C in an atmospheric electrical furnace. According to the experimental results the nanostructured coatings showed a better oxidation resistance than the conventional ones. The improved oxidation resistance of the nanocoating could be explained by the change in structure to a dense and more packed structure in this coating. The mechanical properties of the coatings were tested using the thermal cyclic, nanoindentation and bond strength tests, during which the nanostructured YSZ coating showed a better performance by structural stability.

  8. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junlei; Han Zhongzhi [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: zuoy@mail.buct.edu.cn [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Tang Yuming [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-01-15

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  9. On the Problem of Wear Resistant Coatings Separation From Tools and Machine Elements

    Science.gov (United States)

    Petrushin, S. I.; Gubaidulina, R. H.; Gruby, S. V.; Likholat, A. V.

    2015-09-01

    The article considers separation of wear resistant coatings of tool and engineering materials which arises both during coating fabrication and use of the product. The cause of this phenomenon is assumed to be related to thermal residual stresses generating on the coating- substrate border. These stresses have been analyzed and methods are provided to calculate it after produced composite material is cooled down from the temperature of coating synthesis to the ambient temperature. A no-fracture condition has been stated in relation to coating- substrate thicknesses, temperature differences and physical and mechanical properties of combined materials. The issue of intermediate layer incorporation with pre-set parameters has been discussed. A co-effect of thermal residual and functional stresses on the strength of the boundary layer has been considered when heating, tension and compression of a product with wear resistant coating. Conclusions have been made, as well as recommendations to improve fracture strength of products with thin wear resistant coatings.

  10. Performance Evaluation and Modeling of Erosion Resistant Turbine Engine Thermal Barrier Coatings

    Science.gov (United States)

    Miller, Robert A.; Zhu, Dongming; Kuczmarski, Maria

    2008-01-01

    The erosion resistant turbine thermal barrier coating system is critical to the rotorcraft engine performance and durability. The objective of this work was to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and thermal gradient environments, thus validating a new thermal barrier coating turbine blade technology for future rotorcraft applications. A high velocity burner rig based erosion test approach was established and a new series of rare earth oxide- and TiO2/Ta2O5- alloyed, ZrO2-based low conductivity thermal barrier coatings were designed and processed. The low conductivity thermal barrier coating systems demonstrated significant improvements in the erosion resistance. A comprehensive model based on accumulated strain damage low cycle fatigue is formulated for blade erosion life prediction. The work is currently aiming at the simulated engine erosion testing of advanced thermal barrier coated turbine blades to establish and validate the coating life prediction models.

  11. The Development of Erosion and Impact Resistant Turbine Airfoil Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    2007-01-01

    Thermal barrier coatings are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments and extend component lifetimes. For thermal barrier coatings designed for turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability. Advanced erosion resistant thermal barrier coatings are being developed, with a current emphasis on the toughness improvements using a combined rare earth- and transition metal-oxide doping approach. The performance of the doped thermal barrier coatings has been evaluated in burner rig and laser heat-flux rig simulated engine erosion and thermal gradient environments. The results have shown that the coating composition optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic durability. The erosion and impact damage mechanisms of the thermal barrier coatings will also be discussed.

  12. Structure and erosion resistance ofNi60A/SiC coatting by laser cladding

    Institute of Scientific and Technical Information of China (English)

    LOU Bai-yang; CHEN Zhen; BAI Wan-jin; DONG Gang

    2006-01-01

    The Ni60A and Ni60A/SiC coatings were obtained by laser cladding on 0.45% C steel. The microstructure and hardness of the coatings were studied by SEM and XRD. The erosion resistances of Ni60A and Ni60A/SiC coatings were also investigated. The results show that the structure of different coatings is up to the temperature gradient and solidifying velocity in metal-melting region during laser cladding process. The coatings consist of a cladding layer, in which dendritic crystal and bulky cell-like crystal exist mainly, and a thermo-affected layer. Ni60A/SiC coating has higher microhardness than that of Ni60A coating, which is mainly caused by SiC and complicated phases formed by Ni, Cr, Fe, C and Si. It is obvious from the erosion test that the Ni60A/SiC coating has high erosion resistance.

  13. Preparation of micro-arc oxidation coatings on magnesium alloy and its thermal shock resistance property

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhaohua; ZENG Xiaobin; YAO Zhongping

    2006-01-01

    In the NaAlO2-Na2SiO3 compound system, the ceramic coatings were prepared on magnesium alloy by micro-arc oxidation. The morphology, phase composition, and thermal shock resistance of the ceramic coatings were studied by scanning electron microscope, X-ray diffraction and thermal shock tests, respectively. The results showed that the ceramic coating contains MgO, MgAl2O4, as well as a little amount of Mg2SiO4. The thickness of the ceramic coatings induced ceramic coating is the best. The hardness of the ceramic coating is up to 10 GPa or so.

  14. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  15. The influence of Si on oxidation resistance of aluminide coatings on TiAl alloy

    OpenAIRE

    M. Goral; G. Moskal; L. Swadzba

    2006-01-01

    Purpose: Increasing oxidation resistance of TiAl intermetallic alloy by depositing aluminide coating by slurrymethod and investigation of the influence of Si addition on isothermal oxidation of TiAlNb intermetallic alloy.Design/methodology/approach: : The isothermal oxidation resistance tests were done in the chamber furnaceat 900ºC for 500h time in the air atmosphere. The structure of coatings was investigated by light and scanningmicroscopy. The chemical composition of coatings and scales w...

  16. The effect of water resistance in the primary coating by silane coupling agents and amine synergists

    Science.gov (United States)

    Kim, Min-Jeong; Min, Kyoungbeom; Kim, Sanghwan; Yoon, Jung-Woo; Kwak, Seungjo; Lee, Ji-hye; Oh, Sungkoog

    2008-11-01

    In order to clarify the relationship between the water resistance and compositional additives in the primary coating for optical fibers, we prepared various primary coatings that contained silane coupling agents in combination with amine synergists. We observed the appearance of the interface between glass and primary coating after soaking in water at 65° for 30 days. Water resistance was found to be heavily influenced by the content and type of silane coupling agents and amine synergists and their trends are reported.

  17. A superficial coating to improve oxidation and decarburization resistance of bearing steel at high temperature

    Science.gov (United States)

    Wang, Xiaojing; Wei, Lianqi; Zhou, Xun; Zhang, Xiaomeng; Ye, Shufeng; Chen, Yunfa

    2012-03-01

    The coating material consisted of aqueous slurry of dolomite, bauxite and silicon carbide mixture. Such a coating material when applied superficially on the steel surface not only enhances oxidation resistance but also helps in inhibiting the decarburization even up to 1250 °C. Metalloscope, XRD and TG-DTA thermal analysis revealed that the formation of a newly densified coating comprised of spinels and the reducing atmosphere formed by the oxidation of SiC improved the resistance of oxidation and decarburization.

  18. Producing cobalt–graphene composite coating by pulse electrodeposition with excellent wear and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cansen; Su, Fenghua, E-mail: fhsu@scut.edu.cn; Liang, Jizhao

    2015-10-01

    Graphical abstract: - Highlights: • Graphene oxide/cobalt coatings are synthesized by pulse electrodeposition. • Incorporating GO refines the grain size and changes the microstructure of the coating. • Incorporating GO greatly improves the friction reduction and wear resistance of the coating. • The corrosion resistance is enhanced by the incorporation of GO. - Abstract: Cobalt (Co) and graphene oxide/cobalt (GO/Co) composite coatings were fabricated by pulse electrodeposition technique from an aqueous bath containing cobalt sulfate and GO, etc. Effect of the incorporations of GO on morphology, phase structure, average grain size and corrosion and wear resistance of the resulting composite coatings were evaluated in detail. Scanning electron microscope (SEM) and energy dispersed X-ray (EDX) show that the GO nanosheets disperse homogeneously in the composite coating and the incorporations of GO change the morphologies of the deposit from conical shaped structure to protruding structure. In addition, the co-deposition GO with Co ions favor the formation of hcp (1 0 0), (0 0 2) and (1 0 1) textures in the composite coating and have functions of grain refining and hardness enhancement. The wear tests show that the incorporations of GO in the coating improve the wear resistance and friction reduction of the deposit. The electrochemical corrosion tests using potentiodynamic polarization and electrochemical impedance spectroscopy show that the GO/Co composite coating possesses better corrosion resistance than the pure Co coating.

  19. Comprehensive study of the abrasive wear and slurry erosion behavior of an expanded system of high chromium cast iron and microstructural modification for enhanced wear resistance

    Science.gov (United States)

    Chung, Reinaldo Javier

    High chromium cast irons (HCCIs) have been demonstrated to be an effective material for a wide range of applications in aggressive environments, where resistances to abrasion, erosion and erosion-corrosion are required. For instance, machinery and facilities used in mining and extraction in Alberta's oil sands suffer from erosion and erosion-corrosion caused by silica-containing slurries, which create challenges for the reliability and maintenance of slurry pumping systems as well as other processing and handling equipment. Considerable efforts have been made to determine and understand the relationship between microstructural features of the HCCIs and their wear performance, in order to guide the material selection and development for specific service conditions with optimal performance. The focus was previously put on a narrow group of compositions dictated by ASTM A532. However, with recent advances in casting technology, the HCCI compositional range can be significantly expanded, which potentially brings new alloys that can be superior to those which are currently employed. This work consists of three main aspects of study. The first one is the investigation of an expanded system of white irons with their composition ranging from 1 to 6 wt.% C and 5 to 45 wt.% Cr, covering 53 alloys. This work has generated wear and corrosion maps and established correlation between the performance and microstructural features for the alloys. The work was conducted in collaboration with the Materials Development Center of Weir Minerals in Australia, and the results have been collected in a database that is used by the company to guide materials selection for slurry pump components in Alberta oil sands and in other mining operations throughout the world. The second part consists of three case studies on effects of high chromium and high carbon, respectively, on the performance of the HCCIs. The third aspect is the development of an approach to enhance the wear resistance of

  20. The Frame and Function Analysis of the Non-Crystal Bonding Brushing Plating Ni-W-SiC Coat

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-feng; XIANG wei-xiang; CAO Shou-liang

    2004-01-01

    The article discusses the electric brushing plating technology of the Ni-W-SiC non-crystal bonding coat.By the brushing plating technology it attains the non-crystal bonding coat which comprises 6.9% (wt) SiC. It analyzes the structure of the coat by the X-ray diffraction technology. Meantime, the hardness, abrasion resistance and resistance to the oxidation under high temperature of the coat are also discussed in this article. The conclusion demonstrates that the hardness, abrasion resistance and resistance to oxidation under high temperature of the non-crystal bonding coat obviously improve because of the age-hardening functionof the SiC particle.

  1. Structure and Corrosion Resistance of Microarc Oxidation Coatings on AZ91D Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    Cui Shihai; Han Jianmin; Li Weijing; Li Ronghua; Zhu Xiaowen; Wang Jinhua

    2004-01-01

    Magnesium alloys are widely used as shells of 3C (computer, mobile phone and consumer electronics) equipments for its impressive mechanical and physical properties, such as low density, good resistance to electromagnetic radiation, suitable for high pressure diecasting and easily recycling, etc. But poor corrosion resistance confines its extensively application. In this paper, protective coatings was successfully prepared on AZ91D magnesium alloys by micro-arc oxidation (MAO) and painting process. Microstructures and phases of MAO coatings were invesgated with scanning electron microscope (SEM) and X-Ray diffractometer. Mechanical properties of MAO coating, such as adhesive force and corrosion resistance, were also tested. Results showed that MAO coatings were a good base for painting process. MAO coatings with paint have good adhesive properties to base metal and excellent corrosion resistance. Micro-arc oxidation with painting process is a good kind of surface treatment to improve the corrosion resistance of mobile phone shell made of AZ91D magnesium alloys.

  2. A review of micro-scale abrasion testing

    Energy Technology Data Exchange (ETDEWEB)

    Gant, A J; Gee, M G [Electronics and Modelling Group, Division of Industry and Innovation, Module 9, Space G9-A5, Queens Road, Teddington, Middlesex, TW11 0LW (United Kingdom)

    2011-02-23

    Micro-scale abrasion (commonly referred to as 'ball cratering') is a small-scale tribological test method which can be operated on a desktop. It offers the possibility of providing a quick, cheap, localized abrasion test that can be used with small samples. In principle its operation is simple, but in practice there are issues with wear scar measurement, wear mode and its applicability to a wide variety of monolithic materials and coatings. (topical review)

  3. The hardness, adhesion, and wear resistance of coatings developed for cobalt-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cockeram, B.V.; Wilson, W.L.

    2000-05-01

    One potential approach for reducing the level of nuclear plant radiation exposure that results from activated cobalt wear debris is the use of a wear resistant coating. However, large differences in stiffness between a coating/substrate can result in high interfacial stresses that produce coating de-adhesion when a coated substrate is subjected to high stress wear contact. Scratch adhesion and indentation tests have been used to identify four promising coating processes [1,2]: (1) the use of a thin Cr-nitride coating with a hard and less-stiff interlayer, (2) the use of a thick, multilayered Cr-nitride coating with graded layers, (3) use of the duplex approach, or nitriding to harden the material subsurface followed by application of a multilayered Cr-nitride coating, and (4) application of nitriding alone. The processing, characterization, and adhesion of these coating systems are discussed. The wear resistance and performance has been evaluated using laboratory pin-on-disc, 4-ball, and high stress rolling contact tests. Based on the results of these tests, the best coating candidate from the high-stress rolling contact wear test was the thin duplex coating, which consists of ion nitriding followed deposition of a thin Cr-nitride coating, while the thin Cr-nitride coating exhibited the best results in the 4-ball wear test.

  4. Karakterizacija WCCo/NiCrBSi prevlake otporne na habanje / Characterization of wear resistant plasma sprayed WCCo/NiCrBSi self-fluxing coatings

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2010-04-01

    Full Text Available U radu su analizirani mikrostruktura, mehaničke i tribološke karakteristike (APS prevlake WCCoNiCrBSi koja se primenjuje za reparaciju cilindara nosne noge helikoptera. Tribološka procena prevlake određena je primenom tribometra blok-na-prstenu. Spregnuti materijalblokovi sa prevlakom ispitani su na okaljenom i poboljšanom čeličnom prstenu. Za ukupno odstojanje od 3000 m bili su konstantna brzina 0,5 m/s i opterećenje 400 N. Prednost primene ove prevlake je u značajnom produženju resursa delova uz smanjenje troškova eksploatacije i održavanja. / In this paper, the microstructural, mechanical and tribological properties of WCCoNiCrBSi thermal spray coatings, applied to repair the cylinders of helicopter nasal feet, were analyzed. The process used for coating deposition on steel substrate was the Atmospheric Plasma Spraying (APS.The plasma spray process is a procedure widely used for applying coatings with increased resistance to wear. The combination of WCCo and NiCrBSi powders produced coatings for the protection of metal parts exposed to wear abrasion, erosion and cavitation to 540°C. The WCCoNiCrBSi 50/50% powder is specially developed for the production of coatings of high cohesion and adhesive strength. The coatings are very dense, hard and smooth. Microstructures present in the layers are tungsten carbides and chromium layers that increase resistance to wear and abrasion. Powder is deposited on the substrate rugged with Al2O3. The substrates were heated at temperatures up to 200°C. Powder deposition was performed with the optimal deposition parameters The microstructure and micro hardness of the coating layer was investigated on the cross section of samples using the Pratt & Whitney standard. Micro hardness was tested using the Vickers scale with a load of 300g. The microstructure of the layers was investigated on an optical microscope (OM with a magnification of 400X. Testing of bond strength between coatings and substrates

  5. Anti-reflective and anti-soiling coatings for self-cleaning properties

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, Brenor L.; Nair, Vinod; Dave, Bakul Champaklal

    2016-05-31

    The disclosure discloses abrasion resistant, persistently hydrophobic and oleophobic, anti-reflective and anti-soiling coatings for glass. The coatings described herein have wide application, including for example the front cover glass of solar modules. Methods of applying the coatings using various apparatus are disclosed. Methods for using the coatings in solar energy generation plants to achieve greater energy yield and reduced operations costs are disclosed. Coating materials are formed by combinations of hydrolyzed silane-base precursors through sol-gel processes. Several methods of synthesis and formulation of coating materials are disclosed.

  6. Materials for Advanced Turbine Engines (MATE). Project 4: Erosion resistant compressor airfoil coating

    Science.gov (United States)

    Rashid, J. M.; Freling, M.; Friedrich, L. A.

    1987-01-01

    The ability of coatings to provide at least a 2X improvement in particulate erosion resistance for steel, nickel and titanium compressor airfoils was identified and demonstrated. Coating materials evaluated included plasma sprayed cobalt tungsten carbide, nickel carbide and diffusion applied chromium plus boron. Several processing parameters for plasma spray processing and diffusion coating were evaluated to identify coating systems having the most potential for providing airfoil erosion resistance. Based on laboratory results and analytical evaluations, selected coating systems were applied to gas turbine blades and evaluated for surface finish, burner rig erosion resistance and effect on high cycle fatigue strength. Based on these tests, the following coatings were recommended for engine testing: Gator-Gard plasma spray 88WC-12Co on titanium alloy airfoils, plasma spray 83WC-17Co on steel and nickel alloy airfoils, and Cr+B on nickel alloy airfoils.

  7. Bioinspired Zwitterionic Surface Coatings with Robust Photostability and Fouling Resistance.

    Science.gov (United States)

    Huang, Chun-Jen; Chu, Sz-Hau; Wang, Lin-Chuan; Li, Chien-Hung; Lee, T Randall

    2015-10-28

    Great care has been paid to the biointerface between a bulk material and the biological environment, which plays a key role in the optimized performance of medical devices. In this work, we report a new superhydrophilic adsorbate, called L-cysteine betaine (Cys-b), having branched zwitterionic groups that give rise to surfaces and nanoparticles with enhanced chemical stability, biofouling resistance, and inertness to environmental changes. Cys-b was synthesized from the amphoteric sulfur-containing amino acid, L-cysteine (Cys), by quaternization of its amino group. Gold surfaces modified with Cys-b exhibited prominent repellence against the nonspecific adsorption of proteins, bacteria, and fibroblast cells. In addition, Cys-b existed in zwitterionic form over a wide pH range (i.e., pH 3.4 to 10.8), and showed excellent suppression in photoinduced oxidation on gold substrates. Furthermore, the modification of hollow Ag@Au nanoshells with Cys-b gave rise to nanoparticles with excellent colloidal stability and resistance to coordinative interaction with Cu(2+). Taken together, the unique features of Cys-b offer a new nanoscale coating for use in a wide spectrum of applications.

  8. Effect of Nb Doping on High Temperature Oxidation Resistance of Ti-Al Alloyed Coatings

    Directory of Open Access Journals (Sweden)

    DAI Jing-jie

    2017-02-01

    Full Text Available Ti-Al alloyed coatings with different Nb doping contents were fabricated on TC4 titanium alloy by laser surface alloying to improve high temperature oxidation resistance of the alloy. Structures and high temperature oxidation behaviors of the alloyed coatings were analyzed and tested by X-ray diffraction (XRD, scanning electron microscope (SEM, energy dispersive spectrometer (EDS and box-type resistance furnace. The results show that the alloyed coatings consist of TiAl and Ti3Al, and no niobium compound are formed in Ti-Al-Nb alloyed coatings. The alloyed coatings are uniform and exhibit excellent metallurgical bonding with the substrates. A large amount of surface cracks and a few penetrating cracks are formed in Ti-Al alloyed coating without Nb doping, while no obvious cracks are formed in Ti-Al alloyed coating with Nb doping. The oxidation mass gains of all the alloyed coatings were significantly lower than those of the substrate. The alloyed coatings with Nb doping exhibit more excellent high temperature oxidation resistance due to the beneficial machanism of Nb doping. The mechanism of Nb doping on improving high temperature oxidation resistance of Ti-Al alloyed coatings includes reducing the defect concentration of TiO2, refining oxide grains and promoting the formation of Al2O3.

  9. Development and Life Prediction of Erosion Resistant Turbine Low Conductivity Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

    2010-01-01

    Future rotorcraft propulsion systems are required to operate under highly-loaded conditions and in harsh sand erosion environments, thereby imposing significant material design and durability issues. The incorporation of advanced thermal barrier coatings (TBC) in high pressure turbine systems enables engine designs with higher inlet temperatures, thus improving the engine efficiency, power density and reliability. The impact and erosion resistance of turbine thermal barrier coating systems are crucial to the turbine coating technology application, because a robust turbine blade TBC system is a prerequisite for fully utilizing the potential coating technology benefit in the rotorcraft propulsion. This paper describes the turbine blade TBC development in addressing the coating impact and erosion resistance. Advanced thermal barrier coating systems with improved performance have also been validated in laboratory simulated engine erosion and/or thermal gradient environments. A preliminary life prediction modeling approach to emphasize the turbine blade coating erosion is also presented.

  10. Hexagonal Boron Nitride Nanosheets as High-Performance Binder-Free Fire-Resistant Wood Coatings.

    Science.gov (United States)

    Liu, Juanjuan; Kutty, Rajendrannair Govindan; Zheng, Qingshen; Eswariah, Varrla; Sreejith, Sivaramapanicker; Liu, Zheng

    2017-01-01

    Hexagonal boron nitride (h-BN) nanosheets are synthesized through a facile shear force liquid phase exfoliation method and their use as a binder-free oxidation and fire-resistant wood coating is demonstrated. Characterized by intrinsic low thermal diffusivity and thermal effusivity, h-BN nanosheet coatings show an excellent fire resistance and oxidation resistance up to 900 °C in air.

  11. 2D Heterostructure coatings of hBN-MoS2 layers for corrosion resistance

    Science.gov (United States)

    Vandana, Sajith; Kochat, Vidya; Lee, Jonghoon; Varshney, Vikas; Yazdi, Sadegh; Shen, Jianfeng; Kosolwattana, Suppanat; Vinod, Soumya; Vajtai, Robert; Roy, Ajit K.; Sekhar Tiwary, Chandra; Ajayan, P. M.

    2017-02-01

    Heterostructures of atomically thin 2D materials could have improved physical, mechanical and chemical properties as compared to its individual components. Here we report, the effect of heterostructure coatings of hBN and MoS2 on the corrosion behavior as compared to coatings employing the individual 2D layer compositions. The poor corrosion resistance of MoS2 (widely used as wear resistant coating) can be improved by incorporating hBN sheets. Depending on the atomic stacking of the 2D sheets, we can further engineer the corrosion resistance properties of these coatings. A detailed spectroscopy and microscopy analysis has been used to characterize the different combinations of layered coatings. Detailed DFT based calculation reveals that the effect on the electrical properties due to atomic stacking is one of the major reasons for the improvement seen in corrosion resistance.

  12. Abrasion Properties of Steel Fiber Reinforced Silica Fume Concrete According to Los Angeles and Water Abrasion Tests

    Directory of Open Access Journals (Sweden)

    Tsan-Ching CHENG

    2014-12-01

    Full Text Available The current study mainly investigated the influence of different tests on the abrasion resistance of concrete mixed with steel fibers and silica fume. The abrasion resistance was assessed at 28, 56 and 91 days on concretes with water-binder ratios of 0.35 and 0.55 where in some mixes silica fume was substituted by 5 % of cement by weight. Steel fibers of 0.5 % and 1.0 % of concrete volume were also added into the test concrete by replacement of coarse and fine aggregates. The results showed that concrete with higher compressive strength in Los Angeles abrasion tests also had better abrasion resistance. The inclusion of steel fibers into test concrete with a water-binder ratio of 0.35 resulted in a significant increase in compressive strength. This concrete also displayed better abrasion resistance and splitting tensile strength than reference concrete; in the test sample with a water-binder ratio of 0.55, the added steel fibers was unable to effectively produce cementation with the concrete. The inclusion of silica fume improved the abrasion resistance of concretes. In water abrasion testing, the abrasion resistance of concrete containing steel fiber was worse than that of concrete without steel fibers. In the water abrasion testing, the surface of steel fiber reinforced concrete was eroded by water and steel balls, and the impact caused the steel fibers to separate from the concrete and led to higher wear loss. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6460

  13. Abrasion Properties of Steel Fiber Reinforced Silica Fume Concrete According to Los Angeles and Water Abrasion Tests

    Directory of Open Access Journals (Sweden)

    Tsan-Ching CHENG

    2014-12-01

    Full Text Available The current study mainly investigated the influence of different tests on the abrasion resistance of concrete mixed with steel fibers and silica fume. The abrasion resistance was assessed at 28, 56 and 91 days on concretes with water-binder ratios of 0.35 and 0.55 where in some mixes silica fume was substituted by 5 % of cement by weight. Steel fibers of 0.5 % and 1.0 % of concrete volume were also added into the test concrete by replacement of coarse and fine aggregates. The results showed that concrete with higher compressive strength in Los Angeles abrasion tests also had better abrasion resistance. The inclusion of steel fibers into test concrete with a water-binder ratio of 0.35 resulted in a significant increase in compressive strength. This concrete also displayed better abrasion resistance and splitting tensile strength than reference concrete; in the test sample with a water-binder ratio of 0.55, the added steel fibers was unable to effectively produce cementation with the concrete. The inclusion of silica fume improved the abrasion resistance of concretes. In water abrasion testing, the abrasion resistance of concrete containing steel fiber was worse than that of concrete without steel fibers. In the water abrasion testing, the surface of steel fiber reinforced concrete was eroded by water and steel balls, and the impact caused the steel fibers to separate from the concrete and led to higher wear loss. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6460

  14. Development of wear-resistant coatings for cobalt-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cockeram, B.V.

    1999-03-01

    The costs and hazards resulting from nuclear plant radiation exposure with activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. However, the hardnesses of many cobalt-base wear alloys are significantly lower than conventional PVD hard coatings, and mechanical support of the hard coating is a concern. Four approaches have been taken to minimize the hardness differences between the substrate and PVD hard coating: (1) use a thin Cr-nitride hard coating with layers that are graded with respect to hardness, (2) use a thicker, multilayered coating (Cr-nitride or Zr-nitride) with graded layers, (3) use nitriding to harden the alloy subsurface followed by application of a multilayered coating of Cr-nitride, and (4) use of nitriding alone. Since little work has been done on application of PVD hard coatings to cobalt-base alloys, some details on process development and characterization of the coatings is presented. Scratch testing was used to evaluate the adhesion of the different coatings. A bench-top rolling contact test was used to evaluate the wear resistance of the coatings. The test results are discussed, and the more desirable coating approaches are identified.

  15. Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dhandapani, Vishnu Shankar [PG & Research Department of Physics, PSG College of Arts & Science, Coimbatore 641 014, Tamil Nadu (India); Center for Nano-Wear, Yonsei University, Seoul 120-749 (Korea, Republic of); Subbiah, Ramesh [Center for Biomaterials, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Department of Biomedical Engineering, Korea University of Science and Technology (UST), Daejon 305-333 (Korea, Republic of); Thangavel, Elangovan [PG & Research Department of Physics, PSG College of Arts & Science, Coimbatore 641 014, Tamil Nadu (India); Center for Nano-Wear, Yonsei University, Seoul 120-749 (Korea, Republic of); Arumugam, Madhankumar [Center of Research Excellence in Corrosion, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Park, Kwideok [Center for Biomaterials, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Department of Biomedical Engineering, Korea University of Science and Technology (UST), Daejon 305-333 (Korea, Republic of); Gasem, Zuhair M. [Center of Research Excellence in Corrosion, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Veeraragavan, Veeravazhuthi, E-mail: vv.vazhuthi@gmail.com [PG & Research Department of Physics, PSG College of Arts & Science, Coimbatore 641 014, Tamil Nadu (India); Kim, Dae-Eun, E-mail: kimde@yonsei.ac.kr [Center for Nano-Wear, Yonsei University, Seoul 120-749 (Korea, Republic of); Department of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2016-05-15

    Highlights: • a-C:Ti nanocomposite coatings were prepared on 316L stainless steel by using R.F. magnetron sputtering method. • Properties of the nanocomposite coatings were analyzed with respect to titanium content. • Corrosion resistance, biocompatibility and hydrophobicity of nanocomposite coating were enhanced with increasing titanium content. • Coating with 2.33 at.% titanium showed superior tribological properties compared to other coatings. - Abstract: Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp{sup 2} bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

  16. Study of Thermal Fatigue Resistance of a Composite Coating Made by a Vacuum Fusion Sintering Method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Thermal fatigue behavior of a Ni-base alloy chromium carbide composite coating made by a vacuum fusion sintering method are discussed. Results show that thermal fatigue behavior is associated with cyclic upper temperature and coating thickness. As the thickness of the coating decreases, the thermal fatigue resistance increases. The thermal fatigue resistance cuts down with the thermal cyclic upper temperature rising. The crack growth rate decreases with the increase in cyclic number until crack arrests. Thermal fatigue failure was not found along the interface of the coating/matrix. The tract of thermal fatigue crack cracks along the interfaces of phases.

  17. Microstructure and wear resistance of electro-thermal explosion sprayed stellite coating used for remanufacturing

    Institute of Scientific and Technical Information of China (English)

    JIN Guo; XU Bin-shi; WANG Hai-dou; LI Qing-fen; WEI Shi-cheng

    2005-01-01

    Electro-thermal explosion directional spraying was used to prepare the stellite coating on substrate of the AISI 1045 steel. The morphologies of cross-section and worn scar, porosity, distribution of elements, microhardness and wear resistance of the coating were determined by means of SEM, EDAX, micro-hardness tester and sliding wear tester. Because of the compact construction, good bonding and high hardness, the coating is characterized by good wear resistance. The results show that the mainly failure mode of the stellite coating is microplowing.

  18. Effect of coatings on oxidation resistance and mechanical performance of Ti60 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tang Zhaolin; Wang Fuhui; Wu Weitao [Academia Sinica, Shenyang, LN (China). Inst. of Corrosion and Protection of Metals; Wang Qingjiang; Li Dong [Institute of Metals Research, The Chinese Academy of Sciences, Shenyang 110015 (China)

    1998-10-31

    The effect of several sputtered coatings on oxidation resistance and mechanical performance of Ti60 alloy was investigated. Sputtered pure Al, Ti-36Al, Ni-16Cr-2.5Al(wt%) coatings and reactively-sputtered Al{sub 2}O{sub 3} film were effective in inhibiting the oxidation and oxygen-embrittlement of Ti60 alloy at 600-700 C, while Al{sub 2}O{sub 3} and TiAl coatings exhibited a better effect than Al and NiCrAl coatings from the point of view of coating-substrate compatibility. The tensile test after 100h exposure at 600 C in air also showed that Ti60 alloy with Al{sub 2}O{sub 3} and TiAl coatings exhibited a higher ductility than that with Al and NiCrAl coatings, which exhibited a good correlation with coating-substrate compatibility. (orig.) 17 refs.

  19. 高硼低碳耐磨合金磨料磨损性能研究%Study on Abrasive Wear Performance of High Boron Low Carbon Wear-resistant Alloy

    Institute of Scientific and Technical Information of China (English)

    麻健梅; 王顺波; 苏广才; 汤宏群

    2013-01-01

    借助光学显微镜和SEM电镜观察,运用磨损试验手段及对比研究法,研究了高硼低碳耐磨合金的磨料磨损性能.结果表明,在中、低冲击工况下,高硼低碳耐磨合金的磨损质量损失、相对磨损率均小于高铬铸铁和高锰钢,且磨面磨损形成的沟槽少,压坑小,这显示出了良好的耐磨料磨损性.%The high boron low carbon wear-resistant alloy abrasive wear performance was researched by OM, SEM observation, wear test methods and comparision approach. The results show that in the medium or low impact conditions, the wear mass loss and relative wear rate of high boron low carbon wear-resistant alloy are less than that of high chromium cast iron and high manganese steel. The number of the wear grooves and the pits on the wear surface morphology is smaller, which shows the good characteristics in abrasive wear performance of high boron low carbon wear-resistant alloy.

  20. Research on Grinding and Polishing Technics of Stainless Steel Spade with Coated Abrasive Belt%不锈钢铲的高效机械化砂带磨削及抛光工艺研究

    Institute of Scientific and Technical Information of China (English)

    余岩

    2011-01-01

    针对不锈钢铲形状不规则、手工打磨效率低、环境差、劳动强度大、质量不稳定等问题,提出采用高教砂带磨削的方案,并介绍几种特殊磨头的结构设计和工艺实施.与手工磨削的对比表明:采用新方案可提高效率约3倍,变手工操作为自动化作业,改善作业环境,降低劳动强度,保证产品质量的一致性和稳定性.%To overcome various disadvantages, such as lower efficiency, laboriousness, bad operation environment, and unsta ble quality of manual operation for the stainless steel spade with irregular shapes, the scheme adopting high efficiency grinding and pol ishing with coated abrasive belt was put forward. The structure designs and technics implementations for several special grinding heads were discussed. The results of comparing with manual grinding and polishing demonstrate that many various benefits to the spade ma chining are brought by the new scheme, with efficiency increased by 3 times, tasks changed to automatic from manual, healthy opera tional environment provided, reduced laboring intensity, and assured surface quality.

  1. Cavitation-erosion resistance of arc ion-plated (Ti, Cr) N coatings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The cavitation-erosion behavior of (Ti,Cr)N multi-component coatings produced by arcion-plating on grey cast iron was studied by using an ultrasonic cavitation -erosion testing appara-tus and scanning electron microscopy. The test results indicated that surface roughness of thesubstrate, surface morphology of the coating, substrate bias voltage and the thickness of the coat-ing had certain influence on the erosion rate. Arc ion-plated (Ti,Cr)N multi-component coatingsshowed better cavitation -erosion resistance than single component coatings because of highermicrohardness and good adhesion.

  2. Effect of nano-size nickel particles on wear resistance and high temperature oxidation resistance of ultrafine ceramic coating

    Institute of Scientific and Technical Information of China (English)

    古一; 夏长清; 李佳; 吴安如

    2004-01-01

    In order to improve the wear resistance and high temperature oxidation resistance of titanium and titanium alloy, the high temperature ultra fine ceramic coating containing nano-size nickel particles was prepared by flow coat method on the surface of industrially pure titanium TB1-0. The effects of nano-size nickel particles on the wear resistance and high temperature oxidation resistance of coating substrate system were investigated through oxidation kinetics experiment and wear resistance test. The morphologies of the specimens were examined by means of optical microscopy, scanning electron microscopy and X-ray diffraction. The results show that the high temperature ultra fine ceramic coating has notable protection effect on industrially pure titanium TB1-0 from oxidation. The oxidation and wear resistance properties of the coating can be effectively improved by adding nano-size nickel particles. The decreases from 1. 1 to 0. 6 by adding nano-size nickel particles, and the coating containing 10% (mass fraction) nano-size nickel shows the optimum properties.

  3. Oxidation Resistance of CVD (Chemical Vapor Deposition) Coatings

    Science.gov (United States)

    1987-02-01

    carbonaceous residuoe were overcome, and dense, iadherent, coat-ings which :ýtop oxidat-ion Of the substrate art! reliably produced. The iridium deposition...flow, pressure and geometry within the reaction chamber, and substrate material. For the coating to have high integrity and adhesion to the substrate...entirely produced by Ultramet using chemical vapor deposition and a novel integrated fabrication technique. Coating the inside of a long chamber presents

  4. High temperature ceramic articles having corrosion resistant coating

    Science.gov (United States)

    Stinton, David P.; Lee, Woo Y.

    1997-01-01

    A ceramic article which includes a porous body of SiC fibers, Si.sub.3 N.sub.4 fibers, SiC coated fibers or Si.sub.3 N.sub.4 coated fibers, having at least one surface, the article having a coating of AlN adherently disposed throughout at least a portion of the porous body.

  5. Electrolytic deposition and corrosion resistance of Zn–Ni coatings obtained from sulphate-chloride bath

    Indian Academy of Sciences (India)

    Katarzyna Wykpis; Magdalena Popczyk; Antoni Budniok

    2011-07-01

    Zn–Ni coatings were deposited under galvanostatic conditions on steel substrate (OH18N9). The influence of current density of deposition on the surface morphology, chemical and phase composition was investigated. The corrosion resistance of Zn–Ni coatings obtained at current density 10–25 mA cm-2 are measured, and are compared with that of metallic cadmium coating. Structural investigations were performed by the X-ray diffraction (XRD) method. The surface morphology and chemical composition of deposited coatings were studied using a scanning electron microscope (JEOL JSM-6480) with EDS attachment. Studies of electrochemical corrosion resistance were carried out in the 5% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the ground of these research, the possibility of deposition of Zn–Ni coatings contained 24–26% at. Ni was exhibited. It was stated, that surface morphology, chemical and phase composition of these coatings are practically independent on current density of deposition. On the basis of electrochemical investigations it was found that corrosion resistance of these Zn–Ni coatings is also independent of current density. These coatings are more corrosion resistant in 5% NaCl solution than metallic cadmium. It was suggested that the Zn–Ni coating may be used as a substitute for toxic cadmium.

  6. Examination of Wetting by Liquid Zinc of Steel Sheets Following Various Kinds of Abrasive Blasting

    Directory of Open Access Journals (Sweden)

    Cecotka M.

    2016-06-01

    Full Text Available Abrasive blasting is one of the methods of surface working before hot-dip zinc-coating. It allows not only to remove products of corrosion from the surface, but it also affects the quality of the zinc coating applied later, thereby affecting wettability of surface being zinc-coated. The surface working can be done with different types of abrasive material.

  7. Microstructure and Corrosion Resistance of Electrodeposited Ni-Cu-Mo Alloy Coatings

    Science.gov (United States)

    Meng, Xinjing; Shi, Xi; Zhong, Qingdong; Shu, Mingyong; Xu, Guanquan

    2016-09-01

    This paper deals with the electrodeposition of Ni-Cu-Mo ternary alloy coatings on low-carbon steel substrate from an aqueous citrate sulfate bath. The structures and microstructure of coatings were characterized by scanning electron microscopy and x-ray diffractometry. The corrosion resistance of coatings was investigated by potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy techniques. The results show that the Ni-Cu-Mo coatings are mainly composed of fcc-Ni phase and a small amount of NiCu phase. Ni-Cu-Mo coatings exhibit a nodular surface morphology, and the roughness of electroplated coating increases with the increasing of Na2MoO4·2H2O in the bath. The corrosion performance of the coatings is significantly affected by the Mo content of the alloy coating and their surface morphology. The coating prepared in bath containing 40 g/L Na2MoO4·2H2O has the highest corrosion resistance in 3.5 wt.% NaCl solution, while that prepared in bath containing 60 g/L (or more) Na2MoO4·2H2O shows a lower corrosion resistance due to the presence of microcracks on the coating surface.

  8. Thermally Sprayable Anti-corrosion Marine Coatings Based on MAH-g-LDPE/UHMWPE Nanocomposites

    Science.gov (United States)

    Jeeva Jothi, K.; Santhoskumar, A. U.; Amanulla, Syed; Palanivelu, K.

    2014-12-01

    Polymer composite coatings based on low-density polyethylene (LDPE) and ultra-high-molecular-weight polyethylene (UHMWPE) blends were prepared for marine coatings. The incorporation of carboxyl moiety in the polymer blends of LDPE/UHMWPE was carried out by grafting with maleic anhydride (MAH) at varying concentrations of 1-8 wt.% using reactive extrusion process. An optimum percentage of grafting of 2.1% was achieved with 5 wt.% of maleic anhydride. Further, the nanocomposites of MAH-grafted-LDPE/UHMWPE blends were prepared by incorporating cloisite 15A nanoclay at varying concentrations of 1-4 wt.%. The polymer nanocomposites were converted into fine powders suitable for thermal spray having ≤200 μ particle size using cryogenic grinding. The effect of the intact coatings applied on grit-blasted mild steel by thermal spray technique was evaluated for abrasion resistance, adhesion strength, and corrosion resistance. The corrosion resistance of the polymer nanocomposites was studied by salt spray technique and Electrochemical Impedance Spectroscopy The abrasion resistance of coatings increases with increasing UHMWPE content in the blends. However, blends with higher concentration of UHMWPE resulted in coarse coatings with poor adhesion. The coatings with 90:10 MAH-grafted-LDPE/UHMWPE having 3 wt.% of nanoclay showed good abrasion resistance, adhesion strength, and better corrosion resistance.

  9. Nano Structured Plasma Spray Coating for Wear and High Temperature Corrosion Resistance Applications

    Science.gov (United States)

    Ghosh, D.; Shukla, A. K.; Roy, H.

    2014-04-01

    The nano structured coating is a major challenge today to improve the different mechanical properties, wear and high temperature corrosion resistance behaviour of different industrial alloys. This paper is a review on synthesis of nano powder, plasma spraying methods, techniques of nano structured coating by plasma spray method, mechanical properties, tribological properties and high temperature corrosion behaviour of nano structured coating. Nano structured coatings of ceramic powders/composites are being developed for wide variety of applications like boiler, turbine and aerospace industries, which requires the resistance against wear, corrosion, erosion etc. The nano sized powders are subjected to agglomeration by spray drying, after which nano structured coating can be successfully applied over the substrate. Nano structured coating shows improved mechanical wear resistance and high temperature corrosion resistance. The significant improvement of wear and corrosion resistance is mainly attributed to formation of semi molten nano zones in case of nano structured coatings. The future scope of application of nano structured coating has also been highlighted in this paper.

  10. A Study on Corrosion Resistance of Coating System on Steel

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Hwan Seon; Lee, Hyeon Ju; Kim, Kang Seok [Korea Electricity Power Research Institute, Daejeon (Korea, Republic of); Lee, Chul Woo [KEPCO E and Co., Yongin (Korea, Republic of)

    2007-04-15

    The design purpose of architectural finish on steel structures is to prevent corrosion in the respect of structural durability, function, beauty and economy. In particular, as structures located on shores is easily degraded due to damage from salt, it is necessary to evaluate the applied coating systems on steel structures. This study is focused on anti-corrosive tests of both steel surfaces and high strength bolts. Two kinds of tests were conducted on each specimen under the condition of outdoor exposure and salt spray comparatively during 760 hours. In case of coating systems on steel surfaces, three layered coating system showed the best function among the various coating systems. Regarding the coating systems on high strength bolts, the coating system composed of zinc dust on hot dip galvanized coating was found to be the best against corrosion.

  11. Wear Behavior of Laser-Cladded Co-Cr-Mo Coating on γ-TiAl Substrate

    Science.gov (United States)

    Barekat, Masoud; Shoja Razavi, Reza; Ghasemi, Ali

    2017-07-01

    In this study, laser cladding of Co-Cr-Mo alloy on a γ-TiAl substrate was performed to investigate the wear behavior of coated and uncoated TiAl alloy at room temperature. Dry sliding wear tests were conducted for coated and uncoated counterfaces against three pins of alumina, Inconel 718 and Co-Cr-Mo. Overall, laser cladding of Co-Cr-Mo powder resulted in the formation of a thick coating with minimal imperfections, as well as increasing the wear resistance of TiAl alloy. The results of wear tests indicated that the relative wear resistance was about 1.97, 2.17, and 1.92 for sliding against alumina, Inconel 718, and Co-Cr-Mo pins, respectively. The investigation of worn surfaces also showed that the abrasive wear mechanism was dominant for all samples. In addition, severe abrasive wear was changed to mild abrasive wear by local formation of chromium-based oxides.

  12. Electrodeposition and Corrosion Resistance Properties of Zn-Ni/TiO2 Nano composite Coatings

    Directory of Open Access Journals (Sweden)

    B. M. Praveen

    2011-01-01

    Full Text Available Nano sized TiO2 particles were prepared by sol-gel method. TiO2 nano particles were dispersed in zinc-nickel sulphate electrolyte and thin film of Zn-Ni-TiO2 composite was generated by electrodeposition on mild steel plates. The effect of TiO2 on the corrosion behavior and hardness of the composite coatings was investigated. The film was tested for its corrosion resistance property using electrochemical, weight loss, and salt spray methods. The paper revealed higher resistance of composite coating to corrosion. Microhardness of the composite coating was determined. Scanning electron microscope images and X-ray diffraction patterns of coating revealed its fine-grain nature. Average crystalline size of the composite coating was calculated. The anticorrosion mechanism of the composite coating was also discussed.

  13. Effects of Nano Pigments on the Corrosion Resistance of Alkyd Coating

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Alkyd coatings embedded with nano-TiO2 and nano-ZnO pigments were prepared. The effects of nano pigments on anticorrosion performance of alkyd coatings were investigated using electrochemical impedance spectrum (EIS). For the sake of comparison, the corrosion protection of alkyd coatings with conventional TiO2 and ZnO was also studied. It was found that nano-TiO2 pigment improved the corrosion resistance as well as the hardness of alkyd coatings. The optimal amount of nano-TiO2 in a colored coating for corrosion resistance was 1%. The viscosities of alkyd coatings with nanometer TiO2 and ZnO and conventional TiO2 and ZnO pigments were measured and the relation between viscosity and anticorrosion performance was discussed.

  14. Development of wear-resistant coatings for cobalt-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cockeram, B.V.

    1999-10-22

    The level of nuclear plant radiation exposure due to activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. Laboratory pin-on-disc and rolling contact wear tests were used to evaluate the wear performance of several coatings. Based on the results of these tests, multilayer Cr-nitride coatings and ion nitriding are the most promising approaches.

  15. 斜轧中铬半钢磨球的冲击疲劳和磨损性%Impact Fatigue Resistance and Abrasiveness of Cross Rolled Medium Chromium Semi-Steel for Grinding Ball

    Institute of Scientific and Technical Information of China (English)

    李慧

    2001-01-01

    The repeated low-energy impact fatigue resistance and abrasiveness of cross rolled 1.85%C - 5.86%Cr medium chromium semi-steel have been studied. The results indicated that the impact fatigue life of cross rolled medium chromium semi-steel grinding ball is higher than that of casting grinding ball, and the higher impact fatigue resistance and abrasiveness of ball could be got by adequate rolled residual heat treated.%通过落球和冲击磨损试验,研究了斜轧1.85%C、5.86%Cr中铬半钢磨球的抗小能量多冲击破坏能力和耐磨性。结果表明:斜轧中铬半钢磨球的冲击疲劳寿命高于铸造半钢磨球。该球经适当的热轧余热热处理,可获得较高的抗多冲击破坏能力与耐磨性能。

  16. Influence of Nano-Al Concentrates on the Corrosion Resistance of Epoxy Coatings

    Institute of Scientific and Technical Information of China (English)

    Yongchun Liang; Fu-Chun Liu; Ming Nie; Shuyan Zhao; Jiedong Lin; En-Hou Han

    2013-01-01

    A two-stage process was used to produce nano-composite epoxy coatings.The first step involved preparing nano-Al concentrates with high concentration and low viscosity,and the second step produced nanocomposite epoxy coatings by mixing the nano-Al concentrates and epoxy resin.Later,the coating was examined with immersion and salt spray tests.The coatings were characterized by electrochemical impedance spectroscopy (EIS),scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).The results showed that the 5% nano-Al significantly improves the corrosion resistance of the coatings.There are two effects of nano-Al on the coating.Nano-Al is corroded initially to protect the substrate from corrosion,and then the aluminum oxide and aluminum hydroxide were produced after corrosion of nano-Al,which hindered the transmission of corrosion fluid into the coatings.

  17. Corrosion resistance, composition and structure of RE chemical conversion coating on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Golden yellow rare earths chemical conversion coating was obtained on the surface of magnesium alloy by immersing in cerium sulfate solution.The corrosion resistance of RE conversion coating was evaluated using immersion test and potentiodynamic polarization measurements in 3.5%NaCl solution.The morphologies of samples before corrosion and after corrosion were observed by SEM.The structures and compositions of the RE conversion coating were studied by means of XPS.XRD and IR.The results show that,the conversion coating consists of mainly two kinds of element Ce and O,the valences of cerium are+3 and+4.and OH exists in the coating.The anti-corrosion property of magnesium alloy is increased obviously by rare earths conversion coating,Its self-corrosion current density decreases and the coating has self-repairing capability in the corrosion process in 3.5%NaCl solution.

  18. Pack Aluminide Coatings Formed at 650 ℃ for Enhancing Oxidation Resistance of Low Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    Z. D. Xiang; S. R. Rose; P. K. Datta

    2004-01-01

    This study aims to investigate the feasibility of forming iron aluminide coatings on a commercial 9Cr-lMo (wt.%)alloy steel by pack cementation at 650 ℃ in an attempt to improve its high temperature oxidation resistance. Pack powders containing Al, Al2O3 and a series of halide salts were used to carry out the coating deposition experiments, which enabled identification of the most suitable activator for the pack aluminising process at the intended temperature. The effect of pack aluminium content on the growth kinetics and microstructure of the coatings was then studied by keeping deposition conditions and pack activator content constant while increasing the pack aluminium content from 1.4 wt.% to 6 wt.%. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques were used to analyse the phases and microstructures of the coatings formed and to determine depth profiles of coating elements in the coating layer. Oxidation resistance of the coating was studied at 650 ℃ in air by intermittent weight measurement at room temperature. It was observed that the coating could substantially enhance the oxidation resistance of the steel under these testing conditions, which was attributed to the capability of the iron aluminide phases to form alumina scale on the coating surface through preferential Al oxidation.

  19. Pack Aluminide Coatings Formed at 650℃ for Enhancing Oxidation Resistance of Low Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    Z.D.Xiang; S.R.Rose; P.K.Datta

    2004-01-01

    This study aims to investigate the feasibility of forming iron aluminide coatings on a commercial 9Cr-1Mo (wt.%) alloy steel by pack cementation at 650℃ in an attempt to improve its high temperature oxidation resistance. Pack powders containing Al, Al2O3 and a series of halide salts were used to carry out the coating deposition experiments, which enabled identification of the most suitable activator for the pack aluminising process at the intended temperature. The effect of pack aluminium content on the growth kinetics and microstructure of the coatings was then studied by keeping deposition conditions and pack activator content constant while increasing the pack aluminium content from 1.4 wt.% to 6 wt.%. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques were used to analyse the phases and microstructures of the coatings formed and to determine depth profiles of coating elements in the coating layer. Oxidation resistance of the coating was studied at 650 ~C in air by intermittent weight measurement at room temperature. It was observed that the coating could substantially enhance the oxidation resistance of the steel under these testing conditions, which was attributed to the capability of the iron aluminide phases to form alumina scale on the coating surface through preferential A1 oxidation.

  20. Corrosion Resistance of an electrodeposited Zinc Coating Containing CeO2 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    HE Jian-ping; LUO Xin-yi; CHEN Su-jing; WANG Xian-you

    2004-01-01

    A Zinc coating containing CeO2 nanoparticles has been deposited by electrodeposition in a zinc plating bath.The content of CeO2 in the coating is 0.22 mass%. The results of weight loss experiments and electrochemistry tests show that corrosion resistance of the Zinc coating containing CeO2 nanoparticles is remarkably improved in contrast to the pure zinc coating in 0.5 M MgSO4 solution. The effects of CeO2 microparticles on the corrosion resistance of the zinc coating have been studied, the results show that CeO2 microparticles have no effect on the corrosion resistance of the zinc coating. SEM and XRD experiments suggest that the presence of CeO2 nanoparticles in the coating causes the modification of the surface morphology and preferential orientation of the crystal planes; therefore, the reason for the enhancement of corrosion resistance is mainly related to improvement of the structure of the coating.

  1. Crack resistance of pvd coatings : Influence of surface treatment prior to deposition

    NARCIS (Netherlands)

    Zoestbergen, E; De Hosson, JTM

    2002-01-01

    The crack resistance of three different PVD coatings, TiN, Ti(C,N), and a multilayer system of alternating TiN and TiAlN, have been investigated. The three coating systems were deposited onto substrates with a different surface roughness to study the influence of this pretreatment on the crack resis

  2. Preparation, characterization and wear behavior of carbon coated magnesium alloy with electroless plating nickel interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Yan [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Academician Expert Office Workstation (Jiansheng Pan), Lin’an, Zhejiang Province (China); Feng, Kai, E-mail: fengkai@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Academician Expert Office Workstation (Jiansheng Pan), Lin’an, Zhejiang Province (China); Guo, Xingwu [National Engineering Research Center of Light Alloys Net Forming (LAF), School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhou, Zhifeng [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Dong, Jie [National Engineering Research Center of Light Alloys Net Forming (LAF), School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wu, Yixiong [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Academician Expert Office Workstation (Jiansheng Pan), Lin’an, Zhejiang Province (China)

    2015-02-01

    Highlights: • The carbon film with nickel interlayer (Ni + C coating) is deposited on GW83. • In Ni + C composite coating the carbon coating has good adhesion with the nickel interlayer. • The wear track of Ni + C coating is narrower compared to the bare one. • The wear resistance of GW83 is greatly improved by the Ni + C coating. - Abstract: Poor wear resistance of rare earth magnesium alloys has prevented them from wider application. In this study, composite coating (PVD carbon coating deposited on electroless plating nickel interlayer) is prepared to protect GW83 magnesium alloys against wear. The Ni + C composite coating has a dense microstructure, improved adhesion strength and hardness due to the effective support of Ni interlayer. The wear test result shows that the Ni + C composite coating can greatly prolong the wear life of the magnesium alloy. The wear track of the Ni + C coated magnesium alloy is obviously narrower and shows less abrasive particles as compared with the bare one. Abrasive wear is the wear mechanism of the coatings at the room temperature. In conclusion, the wear resistance of the GW83 magnesium alloy can be greatly improved by the Ni + C composite coating.

  3. FIRE-RESISTANT SHIELDING COATING BASED ON SHUNGITE-CONTAINING PAINT

    National Research Council Canada - National Science Library

    BELOUSOVA Elena Sergeevna; NASONOVA Natalia Viktorovna; LYNKOV Leonid Mihailovich; BORBOTKO Timofei Valentinovich; LISOVSKIY Dmitriy Nikolaevich

    2013-01-01

    .... A composite coating on the basis of a water-based fire-resistant paint filled with shungite nanopowder can be applied onto walls, floors, ceilings and other surfaces in the shielded areas to reduce...

  4. Drag resistance measurements for newly applied antifouling coatings and welding seams on ship hull surface

    DEFF Research Database (Denmark)

    Wang, Xueting; Olsen, S. M.; Andres, E.

    in their newly applied conditions. The effects of water absorption of newly applied antifouling coatings on frictional resistance were measured. A flexible rotor with artificial welding seams on its periphery has been designed and constructed to estimate the influence of welding seams on drag resistance. Both......Drag resistances of newly applied antifouling coatings and welding seams on ship hull surface have been investigated using a pilot-scale rotary setup. Both conventional biocide-based antifouling (AF) coatings and silicone-based fouling release (FR) coatings have been studied and compared...... the density of welding seams (number per 5 m ship side) and the height of welding seams had a significant effect on drag resistance....

  5. Interactions between severe environment and concrete resistance to abrasion and erosion%混凝土磨蚀冲蚀与其它环境因素的耦合作用

    Institute of Scientific and Technical Information of China (English)

    何真

    2015-01-01

    Concrete becomes more and more invulnerable to abrasion/erosion degradation upon severe envi⁃ronmental exposure, especially when the service condition is coupled with chloride salt penetration, sulfate attack,and freezing-thawing cycles,etc. This degradation leads to repeated maintenance or service interrup⁃tion to significant hydraulic and marine infrastructure, resulting in tremendous economic losses. Starting from environmental influence and engineering service characteristics, this paper discusses the concrete resis⁃tance to abrasion-erosion degradation and failure modes under different service conditions. The testing meth⁃ods for concrete resistance to abrasion/erosion, and the microstructural control mechanism are evaluated, and the recommendations for development of high performance concrete for abrasion/erosion resistance appli⁃cations are proposed.%日趋严酷的服役环境使得混凝土磨蚀冲蚀与其它环境因素(氯盐侵蚀、硫酸盐侵蚀、冻融循环等)联合作用的问题愈来愈突出,其后果是导致重要水工、海工混凝土结构反复维修甚至过早失稳破坏,造成严重的经济损失。本文从环境因素和工程服役特性出发,对混凝土在不同工况条件下磨蚀冲蚀类型、破坏机理、评价方法、微结构调控机制等方面进行了阐述,指出需更加重视磨蚀冲蚀与其他环境因素联合作用下混泥土耐久性的研究,为高性能抗冲耐磨混凝土的研究与设计提出了建议。

  6. Tribological properties, corrosion resistance and biocompatibility of magnetron sputtered titanium-amorphous carbon coatings

    Science.gov (United States)

    Dhandapani, Vishnu Shankar; Subbiah, Ramesh; Thangavel, Elangovan; Arumugam, Madhankumar; Park, Kwideok; Gasem, Zuhair M.; Veeraragavan, Veeravazhuthi; Kim, Dae-Eun

    2016-05-01

    Amorphous carbon incorporated with titanium (a-C:Ti) was coated on 316L stainless steel (SS) by magnetron sputtering technique to attain superior tribological properties, corrosion resistance and biocompatibility. The morphology, topography and functional groups of the nanostructured a-C:Ti coatings in various concentrations were analyzed using atomic force microscopy (AFM), Raman, X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Raman and XPS analyses confirmed the increase in sp2 bonds with increasing titanium content in the a-C matrix. TEM analysis confirmed the composite nature of the coating and the presence of nanostructured TiC for Ti content of 2.33 at.%. This coating showed superior tribological properties compared to the other a-C:Ti coatings. Furthermore, electrochemical corrosion studies were performed against stimulated body fluid medium in which all the a-C:Ti coatings showed improved corrosion resistance than the pure a-C coating. Preosteoblasts proliferation and viability on the specimens were tested and the results showed that a-C:Ti coatings with relatively high Ti (3.77 at.%) content had better biocompatibility. Based on the results of this work, highly durable coatings with good biocompatibility could be achieved by incorporation of optimum amount of Ti in a-C coatings deposited on SS by magnetron sputtering technique.

  7. Role of Spore Coat Proteins in the Resistance of Bacillus subtilis Spores to Caenorhabditis elegans Predation▿

    OpenAIRE

    2008-01-01

    Bacterial spores are resistant to a wide range of chemical and physical insults that are normally lethal for the vegetative form of the bacterium. While the integrity of the protein coat of the spore is crucial for spore survival in vitro, far less is known about how the coat provides protection in vivo against predation by ecologically relevant hosts. In particular, assays had characterized the in vitro resistance of spores to peptidoglycan-hydrolyzing enzymes like lysozyme that are also imp...

  8. Thermal Behavior of Nano-TiO2 in Fire-Resistant Coating

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The dispersion state of nano-TiO2 particles was studied by using transmission electron microscopy (TEM)and Fourier transform infrared spectroscopy (FT-IR). Nanoparticles can be fully dispersed by specific hyperdispersant. The improvement of nano-TiO2 in thermal behavior and flame retardation of acrylic polymer and fire-resistant coating was investigated by differential thermal analysis (DTA), thermogravimetry (TG)and fire-resistant time test. It is demonstrated that nano-TiO2 is helpful for enhancing the thermal stability,anti-oxidation and fire-resistant properties of acrylic polymer and fire-resistant coating.

  9. A comparison of the abrasiveness of six ceramic surfaces and gold.

    Science.gov (United States)

    Jacobi, R; Shillingburg, H T; Duncanson, M G

    1991-09-01

    A type III gold alloy and six different ceramic surfaces were secured in an abrasion machine opposing extracted teeth to determine their relative abrasiveness and resistance to wear. The rankings of restorative materials from least abrasive to most abrasive were: gold alloy, polished; cast ceramic, polished; porcelain, polished; cast ceramic, polished and shaded; porcelain, polished and glazed; cast ceramic, cerammed skin shaded; and cast ceramic, cerammed skin unshaded. The ranking of materials from most wear-resistant to least wear-resistant was: gold alloy, cast ceramic cerammed, cast ceramic cerammed and shaded, porcelain polished, porcelain glazed, cast ceramic polished and shaded, and cast ceramic polished.

  10. Characterization, mechanical properties and corrosion resistance of biocompatible Zn-HA/TiO2 nanocomposite coatings.

    Science.gov (United States)

    Mirak, Mohammad; Alizadeh, Morteza; Ghaffari, Mohammad; Ashtiani, Mohammad Najafi

    2016-09-01

    Biocompatible Zinc-hydroxyapatite-titania and Zinc-hydroxyapatite nanocomposite coatings have been prepared by electrodeposition on NiTi shape memory alloy. Structures of coatings were characterized using X-ray diffraction (XRD). It was found that addition of TiO2 particles cause to reduction of crystallite size of coating. Scanning Electronic Microscope (SEM) observation showed that the Zn-HA/TiO2 coating consists of plate-like regions which can express that this plate-like structure can facilitate bone growth. X-ray photoelectron microscope (XPS) was performed to investigation of chemical state of composite coating and showed that Zinc matrix was bonded to oxygen. high-resolution transmission electron microscope (HRTEM) result illustrated the crystalline structure of nanocomposite coating. Mechanical behavior of coating was evaluated using microhardness and ball on disk wear test. The TiO2 incorporated composite coatings exhibited the better hardness and anti-wear performance than the Zn-HA coatings. Polarization measurements have been used to evaluate the electrochemical coatings performance. The Zn-HA/TiO2 composite coatings showed the highest corrosion resistance compared with Zn-HA and bare NiTi. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Microstructure and Oxidation Resistance of Laser Remelted Plasma Sprayed Nicraly Coating

    Directory of Open Access Journals (Sweden)

    Niemiec D.

    2016-06-01

    Full Text Available The article presents results of research relating to the impact of laser treatment done to the surface of plasma sprayed coatings NiCrAlY. Analysis consisted microstructure and oxidation resistance of coatings subjected to two different laser melting surfaces. The test were performed at a temperature 1000°C the samples were removed from the furnace after 25, 300, 500, 750 and 1000 hours. The investigations range included analysis of top surface of coatings by XRD characterization oxides formed types and microscopic investigations of coatings morphology

  12. The Application of Heat and Corrosion Resistant Phosphate Coatings Under Steam Pressure

    Science.gov (United States)

    1974-03-01

    August 1955. Bessey, R. E. and W. M. Kisner , "Heat Resistance of Phos- phate Protective Coatings," Technical Report SA-MR18- 1026, Springfield Armory...phosphate coatings heated in the absence of air lose their corrosion resistance between 400°F and 425’F. Bessey and Kisner ’ determined the weight loss...tests. These coatings had been heated in air at 212F, 300 0 F, and at 100-degree in- tervals up to 14000F. Bessey and Kisner reported that the corrosion

  13. Mechanical and Abrasive Wear Properties of Anodic Oxide Layers Formed on Aluminium

    Institute of Scientific and Technical Information of China (English)

    W.Bensalah; K.Elleuch; M.Feki; M.Wery; H.F.Ayedi

    2009-01-01

    Aluminium oxide coatings were formed on aluminium substrates in oxalic acid-sulphuric acid bath. Abrasion tests of the obtained anodic layers were carried out on a pin-on-disc machine in accordance with the ISO/DP 825 specifications. The Vickers microhardness, D (HV0.2). and the abrasion weight loss, Wa (mg) were measured. Influence of oxalic acid concentration (Cox), bath temperature (T) and anodic current density (J) on D and Wa has been examined, and the sulphuric acid concentration (Caul) was maintained at 160 g.L-1. It was found that high microhardness and abrasive wear resistance of oxide layers were produced under low temperatures and high current densities with the addition of oxalic acid. The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), optical microscopy and glow-discharge optical emission spectroscopy (GDOES). It was found that the chemistry of the anodizing electrolyte, temperature, and current density are the controlling factors of the mechanical properties of the anodic oxide layer.

  14. 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

    or inhibitor. Comparable metallic alloys such as SAM2X5 and SAM1651 may also experience crevice corrosion under sufficiently harsh conditions. Accelerated crevice corrosion tests are now being conducted to intentionally induce crevice corrosion, and to determine those environmental conditions where such localized attack occurs. Such materials are extremely hard, and provide enhanced resistance to abrasion and gouges (stress risers) from backfill operations, and possibly even tunnel boring. The hardness of Type 316L Stainless Steel is approximately 150 VHN, that of Alloy C-22 is approximately 250 VHN, and that of HVOF SAM2X5 ranges from 1100-1300 VHN. These new materials provide a viable coating option for repository engineers. SAM2X5 and SAM1651 coatings can be applied with thermal spray processes without any significant loss of corrosion resistance. Both Alloy C-22 and Type 316L stainless lose their resistance to corrosion during thermal spraying. Containers for the transportation, storage and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) with corrosion resistant coatings are envisioned. For example, an enhanced multi-purpose container (MPC) could be made with such coatings, leveraging existing experience in the fabrication of such containers. These coating materials could be used to protect the final closure weld on SNF/HLW disposal containers, eliminate need for stress mitigation. Integral drip shield could be produced by directly spraying it onto the disposal container, thereby eliminating the need for an expensive titanium drip shield. In specific areas where crevice corrosion is anticipated, such as the contact point between the disposal container and pallet, HVOF coatings could be used to buildup thickness, thereby selectively adding corrosion life where it is needed. Both SAM2X5 & SAM1651 have high boron content which enable them to absorb neutrons and therefore be used for criticality control in baskets. Alloy C-22 and 316L have

  15. Improvement on the Corrosion Resistance of AZ91D Magnesium Alloy by Aluminum Diffusion Coating

    Institute of Scientific and Technical Information of China (English)

    Hongwei HUO; Ying LI; Fuhui WANG

    2007-01-01

    By combination of magnetron sputtering deposition and vacuum annealing, an aluminum diffusion coating was prepared on the substrate of AZ91D alloy to improve its corrosion resistance. The microstructure and composition of the diffusion coating was investigated by scanning electron microscopy and X-ray diffraction. The diffusion coating was mainly comprised of β phase-Al12Mg17. The continuous immersion test in 3.5 wt pct neutral NaCl solution indicated that the specimen with diffusion coating had better corrosion resistance compared with the bare AZ91D alloy specimen. The potentiodynamic polarization measurement indicated that the diffusion coating could function as an effectively protective layer to reduce the corrosion rate of AZ91D alloy when exposed to 3.5 wt pct NaCl solution.

  16. Effect of Post Heat Treatment on Corrosion Resistance of Phytic Acid Conversion Coated Magnesium

    Institute of Scientific and Technical Information of China (English)

    R.K. Gupta; K. Mensah-Darkwa; D. Kumar

    2013-01-01

    An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution.The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid conversion coated magnesium was investigated.It was observed that the microstructure and corrosion resistive properties were improved for the heat treated samples.The corrosion current density for bare magnesium,phytic acid conversion coated magnesium,and post-coating heat treated magnesium was calculated to be 2.48 × 10-5,1.18 × 10-6,and 9.27 × 10-7 A/cm2,respectively.The lowest corrosion current density for the heat treated sample indicated its highest corrosion resistive effect for the magnesium.The maximum corrosion protective nature of the heat treated sample was further confirmed by the largest value of impedance in electrochemical impedance spectroscopy studies.

  17. Ablation Resistance of C/C Composites with Atmospheric Plasma-Sprayed W Coating

    Science.gov (United States)

    Zhou, Zhe; Wang, Yuan; Gong, Jieming; Ge, Yicheng; Peng, Ke; Ran, Liping; Yi, Maozhong

    2016-12-01

    To improve the ablation resistance of carbon/carbon (C/C) composites, tungsten (W) coating with thickness of 1.2 mm was applied by atmospheric plasma spraying. The antiablation property of the coated composites was evaluated by oxyacetylene flame ablation experiments. The phase composition of the coating was investigated by a combination of x-ray diffraction analysis and scanning electron microscopy with energy-dispersive x-ray spectroscopy analysis. The ablation resistance of the coated C/C substrates was compared with that of uncoated C/C composites and C/C-CuZr composites after ablation for 30 s. The properties of the coated C/C composites after ablation time of 10, 30, 60, 90, 120, and 180 s were further studied. The results indicated that the mass and linear ablation rates of the W-coated C/C composites were lower than those of uncoated C/C or C/C-CuZr composites after ablation for 30 s. The coating exhibited heat stability after 120 s of ablation, with mass loss and linear ablation rates of 7.39 × 10-3 g/s and 3.50 × 10-3 mm/s, respectively. However, the W coating became ineffective and failed after ablation for 180 s. Three ablation regions could be identified, in which the ablation mechanism of the coating changed from thermochemical to thermophysical erosion to mechanical scouring with increasing ablation time.

  18. Preparation, antibacterial effects and corrosion resistant of porous Cu–TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Haibo; Zhang, Xiangyu, E-mail: zhangxiangyu@tyut.edu.cn; Geng, Zhenhua; Yin, Yan; Hang, Ruiqiang; Huang, Xiaobo; Yao, Xiaohong; Tang, Bin

    2014-07-01

    Antibacterial TiO{sub 2} coatings with different concentrations of Cu (Cu–TiO{sub 2}) were prepared by micro-arc oxidation (MAO) on pre-sputtered CuTi films. The effect of Cu concentrations in CuTi films on the MAO process was investigated. The Cu–TiO{sub 2} coatings were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The corrosion resistance of Cu–TiO{sub 2} coatings was evaluated via potentiodynamic polarization method. The antibacterial properties were assessed by two methods: spread plate method and fluorescence staining. The experimental results demonstrate that the coatings are porous and consist of anatase phase, rutile phase and unoxidized titanium. The CuTi films are almost completely oxidized and the thickness of all MAO coatings is about 5–10 μm. Cu mainly exists as CuO in the TiO{sub 2} coatings. The Cu–TiO{sub 2} coatings exhibit excellent antibacterial activities, and the antibacterial rate gradually rise with the increase in Cu concentration in the MAO coatings. The corrosion resistance of MAO coatings is also improved slightly.

  19. Evaluation of High Temperature Particle Erosion Resistance of Vanadium-Boride Coating

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E. Y.; Kim, J. H.; Jeong, S. I. [Andong National University, Andong (Korea, Republic of); Lee, S. H.; Eum, G. W. [Corporate R and D Institute Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)

    2015-04-15

    The components in ultra super critical (USC) steam turbine, which is under development for high efficient power generation, are encountering harsher solid particle erosion by iron oxide scales than ones in the existing steam turbines. Therefore, the currently used boride coating will not be able to hold effective protection from particle erosion in USC system and should be replaced by new particle erosion resistant coatings. One of the best protective coatings developed for USC steam turbine parts was found to be vanadium-boride (V-boride) coating which has a hardness of about 3000 HV, much higher than that of boride, 1600∼2000 HV. In order to evaluate particle erosion resistance of the various coatings such as V-boride, boride and Cr-carbide coatings at high temperature, particle erosion test equipment were designed and manufactured. In addition, erosion particle velocity was simulated using FLUENT software based on semi-implicity method for pressure linked equations revised (SIMPLER). Based on experimental results of this work, the vanadium-boride coating was found to be superior to others and to be a candidate coating to replace the boride coating.

  20. Structure and properties of chromium-containing coatings produced by electron-beam facing in the atmosphere

    Science.gov (United States)

    Poletika, I. M.; Golkovskii, M. G.; Krylova, T. A.; Perovskaya, M. V.

    2009-03-01

    The chemical and phase compositions and the structure of layers formed by electron-beam facing of low-carbon steel with mixtures of powdered chromium and chromium carbide in air are studied. The microhardness of the layers is determined over their thickness. The faced steels are tested for bending strength, corrosion resistance, and resistance to abrasive wear. A possible mechanism of formation of the properties of the coating, i.e., the hardness, the wear resistance, and the crack resistance, is considered.

  1. High Corrosion-Resistance Double-Layer Ni-P Coating on Steels

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai; LIU Xian-li; JIANG Zhang-hao; LI Guang-yu; LIAN Jian-she; GU Chang-dong

    2004-01-01

    Double-layer Ni-P alloy coating with a thickness about 20 μm and different Ni-P layers was prepared by electroless deposition and its corrosion resistance was studied. The microstructure and corrosion-resistance of the coatings were analyzed by SEM, XRD, electrochemical polarization measurements and salt spray tests. The salt spray tests showed that the double-layer coating exhibits better corrosion resistance. The time of the emergence of the first red rust spot on the coating surface can reach 384 hours, and the gray rusts were firstly emergered during the salt spray tests. The electrochemical analysis revealed that the difference in the corrosion potential between the double layers plays a very important role in protecting the substrate from rusting.

  2. The corrosion resistance and neutron-absorbing properties of coatings based on amorphous alloys

    Science.gov (United States)

    Sevryukov, O. N.; Polyansky, A. A.

    2016-04-01

    The object of the present study was the corrosion-resistant amorphizing alloys with an increased content of boron for cladding the surface of metals, rapidly quenched alloys without boron for protective coatings on a high-boron cladding layer, as well as steel samples with a protective coating with a high content of boron and without boron. The aim of the work is to investigate the corrosion resistance of a coating in water at the temperature of 40 °C in conditions of an open access of oxygen for 1000 h, as well as the features of the microstructure of clad samples before and after the corrosion tests. New data on the corrosion resistance of Cr18Ni10Ti steel samples with a protective layer from a rapidly quenched alloy Ni-19Cr-10Si (in wt.%) on a high-boron coating have been obtained.

  3. Oxidation resistant chromium coating on Zircaloy-4 for accident tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-15

    The attributes of such a fuel are approved reaction kinetics with steam, a slower hydrogen generation rate, and good cladding thermo-mechanical properties. Many researchers have tried to modify zirconium alloys to improve their oxidation resistance in the early stages of the ATF development. Corrosion resistant coating on cladding is one of the candidate technologies to improve the oxidation resistance of zirconium cladding. By applying coating technology to zirconium cladding, it is easy to obtain corrosion resistance without a change in the base materials. Among the surface coating methods, arc ion plating (AIP) is a coating technology to improve the adhesion owing to good throwing power, and a dense deposit (Fig. 1). Owing to these advantages, AIP has been widely used to efficiently form protective coatings on cutting tools, dies, bearings, etc. In this study, The AIP technique for the protection of zirconium claddings from the oxidation in a high-temperature steam environment was studied. The homogeneous Cr film with a high adhesive ability to the cladding was deposited by AIP and acted as a protection layer to enhance the corrosion resistance of the zirconium cladding. It was concluded that the AIP technology is effective for coating a protective layer on claddings.

  4. Improvement of Microhardness and Corrosion Resistance of Stainless Steel by Nanocomposite Coating

    Directory of Open Access Journals (Sweden)

    Hiba Husam Ismail

    2014-12-01

    Full Text Available Stainless steel (AISI 304 has good electrical and thermal conductivities, good corrosion resistance at ambient temperature, apart from these it is cheap and abundantly available; but has good mechanical properties such as hardness. To improve the hardness and corrosion resistance of stainless steel its surface can be modified by developing nanocomposite coatings applied on its surface. The main objective of this paper is to study effect of electroco-deposition method on microhardness and corrosion resistance of stainless steel, and to analyze effect of nanoparticles (Al2O3, ZrO2 , and SiC on properties of composite coatings. In this paper employed Electroco-deposition process to develop a composite coating with (Ni matrix and Ceramic oxide particles: Al2O3 (135nm, ZrO2 (40nm, and SiC (80nm as reinforcements. The coatings were developed with 10 g/L, and 20 g/L concentrations in bath, at four different current densities (0.5, 1, 2, 3 A/dm2 using Watts bath to study the effect of current density and particle concentration in bath, on structure and properties of the coatings developed. The surface morphology of nanocomposite coating was characterized by Scanning Electron Microscopy (SEM. The hardness of the nanocoating was carried out using Digital Vickers microhardness tester. The corrosion resistance property of nanocomposite coating was carried out in 3.5% NaCl solution used Open circuit potential (OCP and potentialastic polarization. The results showed the nanocomposites coating have a smooth and compact surface and have higher hardness than the uncoated stainless steel (2.3 times, and also found that the nanocomposite coating improves the corrosion resistance significantly (89.25%.

  5. Mechanical and corrosion resistance properties of TiO2 nanoparticles reinforced Ni coating by electrodeposition

    Science.gov (United States)

    Shao, W.; Nabb, D.; Renevier, N.; Sherrington, I.; Luo, J. K.

    2012-09-01

    Coatings have been widely used in engineering and decoration to protect components and products and enhance their life span. Nickel (Ni) is one of the most important hard coatings. Improvement in its tribological and mechanical properties would greatly enhance its use in industry. Nanocomposite coatings of metals with various reinforced nanoparticles have been developed in last few decades. Titania (TiO2) exhibit excellent mechanical properties. It is believed that TiO2 incorporation in Ni matrix will improve the properties of Ni coatings significantly. The main purpose of the current work is to investigate the mechanical and anti-corrosion properties of the electroplated nickel nanocomposite with a small percentage of TiO2. The surface morphology of nanocomposite coating was characterized by scanning electron microscopy (SEM). The hardness of the nanocoating was carried out using micromaterials nanoplatform. The sliding wear rate of the coating at room temperature in dry condition was assessed by a reciprocating ball-on-disk computer-controlled oscillating tribotester. The results showed the nanocomposite coatings have a smoother and more compact surface than the pure Ni layer and have higher hardness and lower wear rate than the pure Ni coating. The anti-corrosion property of nanocomposite coating was carried out in 3.5% NaCl and high concentrated 35% NaCl solution, respectively. The results also showed that the nanocomposite coating improves the corrosion resistance significantly. This present work reveals that incorporation of TiO2 in nickel nanocomposite coating can achieve improved corrosion resistance and mechanical properties of both hardness and wear resistance performances, and the improvement becomes stronger as the content of TiO2 is increased.

  6. TiO{sub 2} coated multi-wall carbon nanotube as a corrosion inhibitor for improving the corrosion resistance of BTESPT coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuping; Zhu, Hongzheng; Zhuang, Chen [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Chen, Shougang, E-mail: sgchen@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Wang, Longqiang [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Dong, Lihua [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China); Yin, Yansheng, E-mail: ysyin@shmtu.edu.cn [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China)

    2016-08-15

    The composite coatings of TiO{sub 2} coated multi-wall carbon nanotube (MWCNTs)/bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technique and the experimental conditions were optimized to attain the appropriate volume ratio. The modified MWCNTs obviously improved the corrosion resistance of BTESPT and BTESPT/TiO{sub 2} coatings, especially for the long-term corrosion resistance ability because of the good dispersion of MWCNTs. The geometry of composite coatings were explored by scanning electron microscopy, fourier transform infrared spectra and the surface coverage rate (θ), the results indicate that the composite coatings produce good cross-linked structure at the interfacial layer, the coating compactness increases gradually with the addition of TiO{sub 2} and/or MWCNTs, and the composite coating effectively postpones the production of cracks with the addition of MWCNTs. - Highlights: • The composite coatings with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technology. • The formation of composite coating on AA 2024 surface considerably improved the corrosion resistance ability. • The composite coating with a TiO{sub 2} to MWCNTs volume ratio of 4/1 shows the best corrosion resistance. • The kinetic evaluation of inhibitive behavior for different coatings against immersion time was explored.

  7. Wear resistance of ceramic coating on AZ91 magnesium alloy by micro-arc oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hui; LIU Zheng; CHEN Li-jia; CHEN Ji; HAN Zhong

    2006-01-01

    The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation (MAO) was characterized. The results show that the ceramic coating(3.4-23 μm in thickness)on the surface of AZ91 alloy was attained under different micro-arc oxidation treatment conditions, which consist mainly of MgO, Mg2SiO4 and MgSiO3 phases. Nano-hardness in a cross-sectional specimen was determined by nano-indentation experiment. The MAO coatings exhibit higher hardness than the substrate. Dry sliding wear tests for the MAO coatings and AZ91 alloy were also carried out using an oscillating friction and wear tester in a ball-on-disc contact configuration. The wear resistance of the MAO coatings is improved respectively under different treatment time as a result of different structures of ceramic coatings formed on AZ91 alloy.

  8. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    Science.gov (United States)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  9. Plasma Electrolytic Oxidation (PEO) Coatings on an A356 Alloy for Improved Corrosion and Wear Resistance

    Science.gov (United States)

    Peng, Zhijing

    Plasma electrolytic oxidizing (PEO) is an advanced technique that has been used to deposit thick and hard ceramic coatings on aluminium (Al) alloys. This work was however to use the PEO process to produce thin ceramic oxide coatings on an A356 Al alloy for improving corrosion and wear resistance of the alloy. Effects of current density and treatment time on surface morphologies and thickness of the PEO coatings were investigated. The improvement of galvanic corrosion properties of the coated A356 alloy vs. steel and carbon fibre were evaluated in E85 fuel or NaCl environments. Tribological properties of the coatings were studied with comparison to the uncoated A356 substrate and other commercially-used engine bore materials. The research results indicated that the PEO coatings could have excellent tribological and corrosion properties for aluminium engine applications.

  10. Improvement of corrosion resistance of Nisbnd Mo alloy coatings: Effect of heat treatment

    Science.gov (United States)

    Mousavi, R.; Bahrololoom, M. E.; Deflorian, F.; Ecco, L.

    2016-02-01

    In this paper, Nisbnd Mo alloy coatings were deposited from bath containing sodium citrate, nickel sulphate, and sodium molybdate. Essentially, this work is divided into two mains parts: (i) the optimization on the coatings deposition parameters and (ii) the effect of the heat treatment. Polarization curves and electrochemical impedance spectroscopy were acquired using potentiostat/galvanostat and a frequency response analyzer, respectively. Morphology and chemical composition of the coatings were investigated by scanning electron microscopy and energy dispersive spectroscopy, respectively. Polarization curves at different condition revealed that electroplating at temperature 40 oC, pH 9 provides a dense coating with high efficiency. Following the optimization of the deposition parameters, the coatings were annealed at 200, 400, and 600 oC for 25 min. The results showed that the coatings obtained at temperature 40 oC, pH 9, and annealing at 600 oC has the highest corrosion resistance and microhardness.

  11. Oxidation-resistant interfacial coatings for continuous fiber ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Besmann, T.M.; Bleier, A. [Oak Ridge National Lab., TN (United States); Shanmugham, S.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-08-01

    Continuous fiber ceramic composites mechanical behavior are influenced by the bonding characteristics between the fiber and the matrix. Finite modeling studies suggest that a low-modulus interfacial coating material will be effective in reducing the residual thermal stresses that are generated upon cooling from processing temperatures. Nicalon{trademark}/SiC composites with carbon, alumina and mullite interfacial coatings were fabricated with the SiC matrix deposited using a forced-flow, thermal gradient chemical vapor infiltration process. Composites with mullite interfacial coatings exhibited considerable fiber pull-out even after oxidation and have potential as a composite system.

  12. Electroless Ni-P/Ni-B duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, T.S.N. Sankara; Krishnaveni, K.; Seshadri, S.K

    2003-12-20

    The present work deals with the formation of Ni-P/Ni-B duplex coatings by electroless plating process and evaluation of their hardness, wear resistance and corrosion resistance. The Ni-P/Ni-B duplex coatings were prepared using dual baths (acidic hypophosphite- and alkaline borohydride-reduced electroless nickel baths) with both Ni-P and Ni-B as inner layers and with varying single layer thickness. Scanning electron microscopy (SEM) was used to assess the duplex interface. The microhardness, wear resistance and corrosion resistance of electroless nickel duplex coatings were compared with electroless Ni-P and Ni-B coatings of similar thickness. The study reveals that the Ni-P and Ni-B coatings are amorphous in their as-plated condition and upon heat-treatment at 450 deg. C for 1 h, both Ni-P and Ni-B coatings crystallize and produce nickel, nickel phosphide and nickel borides in the respective coatings. All the three phases are formed when Ni-P/Ni-B and Ni-B/Ni-P duplex coatings are heat-treated at 450 deg. C for 1 h. The duplex coatings are uniform and the compatibility between the layers is good. The microhardness, wear resistance and corrosion resistance of the duplex coating is higher than Ni-P and Ni-B coatings of similar thickness. Among the two types of duplex coatings studied, hardness and wear resistance is higher for coatings having Ni-B coating as the outer layer whereas better corrosion resistance is offered by coatings having Ni-P coating as the outer layer.

  13. Dry wear behaviors of wear resistant composite coatings produced by laser cladding

    Institute of Scientific and Technical Information of China (English)

    Jiang Xu; Wenjin Liu; Minlin Zhong

    2004-01-01

    Using different proportional mixtures of Ni-coated MoS2, TiC and pure Ni powders, new typical wear resistant and selflubricant coatings were formed on low carbon steel by laser cladding process. The microstructures and phase composition of the composite coatings were studied by SEM and XRD. The typical microstructure of the composite coating is composed of multisulfide phases including binary element sulfide and ternary element sulfide, γ-Ni, TiC and Mo2C. Wear tests were carried out using an FALEX-6 type pin-on-disc machine. The friction coefficient and mass loss of three kinds of MoS2/TiC/Ni laser clad coatings are lower than those of quenched 45 steel, and the worn surfaces of the laser cladding coatings are very smooth. Because of high hardness combined with low friction, the laser cladding composite coating with a mixture of 70% Ni-coated MoS2, 20%TiC and 10%pure Ni powder presents better wear behaviors than the composite coating with other powder blends. The composition analysis of the worn surface of GCr15 bearing steel shows that the transferred film from the laser cladding coating to the opposite surface of GCr15beating steel contains an amount of sulfide, which can change the micro-friction mechanism and lead to a reduced friction coefficient.

  14. Nanostructured wear resistant coating for reversible cultivator shovels: An experimental investigation

    Science.gov (United States)

    Dave, V.; Rao, G. P.; Tiwari, G. S.; Sanger, A.; Kumar, A.; Chandra, R.

    2016-04-01

    Cultivator, one of the agriculture farm tool, extensively suffers from the wear problem. In this paper, we report nanostructured chromium nitrite (CrN) coating for the cultivator shovels to mitigate wear problem. The (CrN) coating was developed using DC magnetron sputtering technique at 200 °C. The structural, morphological, hydrophobic and wear properties were investigated using X-ray diffractometer, scanning electron microscope, contact angle goniometer and custom designed soil bin assembly. The XRD reveals that the deposited coating was polycrystalline in nature with cubic structure. Also, The deposited coating was found to be anti wear resistant as well as hydrophobic in nature. The gravimetric wear for the coating developed at 200 °C coated was found out to be 8.15 gm and for non coated it was 14.48 gm tested for 100 hrs. The roughness of the coating plays an important role in determining the hydrophobicity of the coated film. Roughness and contact angle measured for 200 °C coated shovel was found out to be 11.17 nm and 105 ° respectively.

  15. Improvement of corrosion resistance of Ni−Mo alloy coatings: Effect of heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi, R., E-mail: mousavi@scu.ac.ir [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Bahrololoom, M.E. [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Deflorian, F.; Ecco, L. [Department of Industrial Engineering, University of Trento, via Sommarive 9, Trento (Italy)

    2016-02-28

    Graphical abstract: - Highlights: • Conjunction between SEM, EIS, and Tafel measurements to obtain a coat with dense morphology and without crack. • An inverse Hall-Petch effect is observed after annealing the coatings, i.e. the coatings get harder as the grain size is increased by increasing annealing temperature up to 600 {sup o}C. • Heat treatment can improve the mechanical and corrosion properties of coatings. - Abstract: In this paper, Ni−Mo alloy coatings were deposited from bath containing sodium citrate, nickel sulphate, and sodium molybdate. Essentially, this work is divided into two mains parts: (i) the optimization on the coatings deposition parameters and (ii) the effect of the heat treatment. Polarization curves and electrochemical impedance spectroscopy were acquired using potentiostat/galvanostat and a frequency response analyzer, respectively. Morphology and chemical composition of the coatings were investigated by scanning electron microscopy and energy dispersive spectroscopy, respectively. Polarization curves at different condition revealed that electroplating at temperature 40 {sup o}C, pH 9 provides a dense coating with high efficiency. Following the optimization of the deposition parameters, the coatings were annealed at 200, 400, and 600 {sup o}C for 25 min. The results showed that the coatings obtained at temperature 40 {sup o}C, pH 9, and annealing at 600 {sup o}C has the highest corrosion resistance and microhardness.

  16. Contamination resistant coatings for enhanced laser damage thresholds

    Science.gov (United States)

    Weiller, Bruce H.; Fowler, Jesse D.; Villahermosa, Randy M.

    2012-11-01

    This paper describes a novel approach for the suppression of contamination enhanced laser damage to optical components by the use of fluorinated coatings that repel organic contaminates. In prior work we studied laser damage thresholds induced by ppm levels of toluene under nanosecond 1.064 μm irradiation of fused silica optics. That work showed that moderate vapor-phase concentrations (alcohols dramatically increased the laser damage threshold. The data are consistent with the hypothesis that water and alcohols interact more favorably with the hydroxylated silica surface thereby displacing toluene from the surface. In this work, preliminary results show that fluorinated self assembled monolayer coatings can be used to accomplish the same effect. Optics coated with fluorinated films have much higher survival rates compared with uncoated optics under the same conditions. In addition to enhancing survival of laser optics, these coatings have implications for protecting spacecraft imaging optics from organic contamination.

  17. Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

    2005-01-30

    This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

  18. Improving oxidation resistance and thermal insulation of thermal barrier coatings by intense pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mei Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Liu Xiaofei; Wang Cunxia; Wang Younian; Dong Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Pulsed electron beam was used for sealing ZrO{sub 2} thermal barrier coating prepared by electron beam-physical vapor deposition. Black-Right-Pointing-Pointer At irradiation energy densities above 8 J/cm{sup 2}, ZrO{sub 2} ceramic coating surface was fully re-melted and became smooth, dense and shiny. Black-Right-Pointing-Pointer The thermal diffusion rate of the irradiated coating was decreased. Black-Right-Pointing-Pointer Thermal insulation properties and high temperature oxidation resistance were improved. - Abstract: In this paper, intense pulsed electron beam was used for the irradiation treatment of 6-8% Y{sub 2}O{sub 3}-stablized ZrO{sub 2} thermal barrier coating prepared by electron beam-physical vapor deposition to achieve the 'sealing' of columnar crystals, thus improving their thermal insulation properties and high temperature oxidation resistance. The electron beam parameters used were: pulse duration 200 {mu}s, electron voltage 15 kV, energy density 3, 5, 8, 15, 20 J/cm{sup 2}, and pulsed numbers 30. 1050 Degree-Sign C cyclic oxidation and static oxidation experiments were used for the research on oxidation resistance of the coatings. When the energy density of the electron beam was larger than 8 J/cm{sup 2}, ZrO{sub 2} ceramic coating surface was fully re-melted and became smooth, dense and shiny. The coating changed into a smooth polycrystalline structure, thus achieving the 'sealing' effect of the columnar crystals. After irradiations with the energy density of 8-15 J/cm{sup 2}, the thermally grown oxide coating thickness decreased significantly in comparison with non-irradiated coatings, showing that the re-melted coating improved the oxidation resistance of the coatings. The results of thermal diffusivity test by laser flash method showed that the thermal diffusion rate of the irradiated coating was lower than that of the coating without irradiation treatment, and the thermal

  19. Investigation on Scratch Resistance of Thin Films Coated on Resin Lens

    Institute of Scientific and Technical Information of China (English)

    LI Wei; LIU Jin-long; WANG Qing-liang

    2004-01-01

    Resin lens are very popular in glasses market. Many technologies have been developed to coat different thin films on resin lens to strengthen its resistance to scratch or wear, but little of the scratch failure mechanism of such thin films are reported. This paper presented the results of several scratch tests performed on three resin lenses coated with different thin films at the normal loads of 98 mN and 49 mN and at sliding velocity of 0.003 3 m/s and 0.001 7 m/s, and the observation of the scratch tracks on the resin lens by SEM. It shows that the resin lenses coated with different thin films have different scratch resistance and different scratch failure mechanism, and the scratch resistance varies at the two different loads and sliding velocity. The experiment provides a new method to evaluate the scratch resistance of resin lens.

  20. Effects of lanthanum addition on corrosion resistance of hot-dipped galvalume coating

    Institute of Scientific and Technical Information of China (English)

    YANG Dong; CHEN Jianshe; HAN Qing; LIU Kuiren

    2009-01-01

    Effects of La addition on corrosion resistance of hot-dipped galvalume coating steel wire were investigated. The corrosion resistance of Zn-Al-Si-La alloy coatings containing 0, 0.02wt.%, 0.05wt.%, 0.1wt.% and 0.2wt.% La were evaluated by various tests such as copper-accelerated acetic acid salt spray testing (CASS), immersion test in 3.5% NaCl solution, electrochemical tests including weak polarization curves and electrochemical impedance spectroscopy (EIS) tests, scanning electron microscope (SEM) test and X-ray diffraction (XRD) test. It was found that the corrosion resistance of galvalume coating could be improved by adding proper amounts of La. Meanwhile, the mechanism of the improvement of corrosion resistance by La addition was discussed.

  1. Glass and glass–ceramic coatings, versatile materials for industrial and engineering applications

    Indian Academy of Sciences (India)

    Amitava Majumdar; Sunirmal Jana

    2001-02-01

    Among various coating systems for industrial and engineering applications, glass and glass–ceramic coatings have advantages of chemical inertness, high temperature stability and superior mechanical properties such as abrasion, impact etc as compared to other coating materials applied by thermal spraying in its different forms viz. PVD, CVD, plasma, etc. Besides imparting required functional properties such as heat, abrasion and corrosion resistance to suit particular end use requirements, the glass and glass–ceramic coatings in general also provide good adherence, defect free surface and refractoriness. Systematic studies covering the basic science of glass and glass–ceramic coatings, the functional properties required for a particular end-use along with the various fields of application have been reviewed in this paper.

  2. Effects of Hybrid Fibre Reinforcement on Fire Resistance Performance and Char Morphology of Intumescent Coating

    Directory of Open Access Journals (Sweden)

    Amir N.

    2016-01-01

    Full Text Available Recent researches of fire retardant intumescent coatings reinforced by single Rockwool and single glass wool fibre at various weight percentages and lengths showed some improvements to the mechanical properties of the coatings and the char produced. Therefore, in this research the fibres were combined together in intumescent coating formulation at several weight percentages and fibre lengths to study their effects towards fire resistance performance and char morphology. The hybrid fibre reinforced intumescent coatings were subjected to two types of fire tests; Bunsen burner at 1000°C and the electric furnace at 800°C for 1 hour, respectively. Steel temperature of the coated samples during Bunsen burner test was recorded to determine the fire resistance performance. Thermal stability of the intumescent coatings and chars was determined by Thermogravimetric Analysis (TGA. The morphology of the coatings and char was then examined by using Scanning Electron Microscopy (SEM and Energy Dispersive Spectrometry (EDS was conducted to obtain elemental composition of the samples. This research concluded that long-hybrid fibre at 12-mm length and 0.6% fibre-weight produced the top performing hybrid fibre intumescent formulation. The hybrid fibres form survived at elevated temperature, hence helped to provide structure and strengthen the char with the highest fire resistance was recorded at steel temperature of 197°C.

  3. [Effect of aurum coating on corrosion resistance of Ni-Cr alloy].

    Science.gov (United States)

    Chen, Zhi-hong; Liu, Li; Mao, Ying-jie

    2007-02-01

    To evaluate the effect of aurum coating on corrosion resistance of Ni-Cr alloy in artificial saliva environment. The corrosion potential (E(corr)), self-corrosion current density (I(corr)), and polarization resistance (R(p)) of three alloys were measured using electrochemical methods to compare the difference of corrosion resistance between aurum-coated Ni-Cr alloy and Ni-Cr alloy or Au alloy. Meanwhile, microstructural and phase diffraction was examined with field scanning electromicroscopy (FSEM) and surface chemical analysis was performed by energy diffraction X-ray (EDX). The I(corr) of aurum-coated Ni-Cr alloy was (0.70 +/- 0.20) x 10(-6) A/cm2, which was significantly higher than that of Au alloy (P Cr alloy (P coated Ni-Cr alloy was (34.77 +/- 12.61) KOmega.cm2, which was higher than that of Ni-Cr alloy (P Cr alloy coated with aurum was better than that of Ni-Cr alloy. The results of EDX indicated that released Ni and Cr of Ni-Cr alloy coated with aurum after test were less than those of Ni-Cr alloy (P coated Ni-Cr alloy is higher than that of Ni-Cr alloy.

  4. Microstructure, mechanical properties, and oxidation resistance of nanocomposite Ti Si N coatings

    Science.gov (United States)

    Zhang, C. H.; Lu, X. C.; Wang, H.; Luo, J. B.; Shen, Y. G.; Li, K. Y.

    2006-07-01

    Ti-Si-N coatings with different silicon contents (0-12 at.%) were deposited onto Si(1 0 0) wafer, AISI M42 high speed steel, and stainless steel plate, respectively. These coatings were characterized and analyzed by using a variety of analytical techniques, such as XRD, AES, SEM, XPS, nanoindentation measurements, Rockwell C-type indentation tester, and scratch tester. The results revealed that the hardness was strongly correlated to the amount of silicon addition into a growing TiN film. The maximum hardness of 47.1 GPa was achieved as the Si content was 8.6 at.%. In the mechanical and oxidation resistance measurements, the Ti-Si-N coatings showed three distinct behaviors. (i) The coatings with Si contents of no more than 8.6 at.% performed good adhesion strength quality onto the HSS substrates. (ii) The fracture toughness of the coatings decreased with the increase in Si content. (iii) The Ti-Si-N coating with 8.6 at.% Si showed the excellent oxidation resistance behavior. The cutting performance under using coolant conditions was also evaluated by a conventional drilling machine. The drills with Ti-Si-N coatings performed much better than the drills with TiN coating and the uncoated drills.

  5. Improving Corrosion Resistance of Cf/Mg Composites using Rare Earth Conversion Coatings

    Institute of Scientific and Technical Information of China (English)

    Song Meihui; Wang Chunyu; Wu Gaohui

    2007-01-01

    The surface of carbon fiber reinforced Mg matrix (Cf/Mg) composites was modified by treatment of rare earth conversion coating, and nontoxic, non-pollution Ce conversion coatings were prepared. The effect of the coatings on corrosion behaviors of composites was investigated by electrochemical polarization technology and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. The higher Ecorr and lower icorr were obtained by Ce conversion coatings. EIS results showed that the higher values of R2 were obtained by treatment containing CeCl3, the high corrosion resistance occured in treatment containing CeCl3, the low corrosion resistance in uncoating sample, the coating of treatment containing Ce(NO3)3 was medium. The microstructure of Ce conversion coatings was observed by scanning electron microscopy (SEM), and the elements of corresponding for coatings was characterized by energy dispersive spectrometer (EDS). The micro-cracks and Ce-riched spherical particles were characteristics of these coatings.

  6. [Effects of TiSi coating on corrosion resistance of dental Co-Cr alloy].

    Science.gov (United States)

    Hu, Bin; Chen, Jie; Zhang, Fu-qiang

    2011-12-01

    To investigate the effect of titanium-silicon(TiSi) coating on corrosion resistance of dental CoCr alloy. The commonly used CoCr alloy was cast into 10mm×10mm×3mm specimen in size. Then the specimen was coated with TiSi on the surface by sol-gel method. The specimens were immersed in artificial saliva. Weight loss method was used to analyze corrosion rate. Element analysis using Auger Electron Spectroscopy (AES) was performed to compare the content of element before and after coating of TiSi in artificial saliva. SAS8.0 software package was used for statistical analysis. By weight lost method, before and after coating TiSi, the corrosive rate was 0.163 g·m(-2)·h(-1) and 0.138 g·m(-2)·h(-1) respectively. With AES, in Co-Cr alloy not coating TiSi, atomic concentration (g·m(-2)) of Ni, Co, Cr and Si was 7.728582657,0.008801153,0.306195965 and 0.194851978,respectively. After coating Ti-Si,the content of Ni, Co, Cr and Si and 4.745189808,0.004718889, 0.153195362 and 0.778406136, respectively. The release rate of the Ni,Co,cr were decreased after coating. TiSi coating can improve corrosion resistance of CoCr alloy.

  7. Microstructure and Wear Behavior of FeBSiNbCr Metallic Glass Coatings

    Institute of Scientific and Technical Information of China (English)

    Jiangbo Cheng; Xiubing Liang; Binshi Xu; Yixiong Wu

    2009-01-01

    In this paper, FeBSiNbCr metallic glass coatings were prepared onto AISI 1045 steel substrate by using wire arc spraying process. The phase and structure of the coating were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning election microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX). The microstructure of the coating consists of full amorphous phase. The coating has high hardness and low porosity. Full density and little oxides are detected in the coating. The mechanical properties, especially wear resistance, were investigated. The relationship between wear behavior and structure of the coatings were analyzed in detail. The main failure mechanism of the metallic glass coating is brittle breaking and fracture. The results indicate that FeBSiNbCr metallic glass coating has excellent resistance to abrasive wear.

  8. Oxidation resistant coatings for CoSb3

    Science.gov (United States)

    Zawadzka, K.; Godlewska, E.; Mars, K.; Nocun, M.

    2012-06-01

    Doped cobalt antimonides, are used as components of thermoelectric devices at temperatures not exceeding 450 °C because of poor thermal and chemical stability. In absence of oxygen they degrade by sublimation of antimony, while in air they easily oxidize to form volatile antimony oxides and non-volatile thick double oxide scales [1]. In both cases, protective coatings are indispensable to ensure safe performance of thermoelectric devices over extended times. The most promising solution, reported so far, is a thick aerogel coating, which practically stops antimony loss by sublimation. The assessment of coating effectiveness is generally based on thermogravimetric tests in vacuum, so permeability of oxygen and protection from oxidation cannot be evaluated. The paper presents investigations on the development of protective coatings, which would prevent oxidation of CoSb3. Two types of coatings were applied: magnetron sputtered Cr-Si thin layers [2] and thick enamel layers. Testing involved interrupted oxidation in air for 20-80 h at 500 °C and 600 °C. The Cr-Si thin layers appeared oxygen-tight at 500 °C while the enamel layers - even at 600 °C.

  9. NANOSCALE BOEHMITE FILLER FOR CORROSION AND WEAR RESISTANT POLYPHENYLENESULFIDE COATINGS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2003-06-26

    The authors evaluated the usefulness of nanoscale boehmite crystals as a filler for anti-wear and anti-corrosion polyphenylenesulfide (PPS) coatings exposed to a very harsh, 300 C corrosive geothermal environment. The boehmite fillers dispersed uniformly into the PPS coating, conferring two advanced properties: First, they reduced markedly the rate of blasting wear; second, they increased the PPS's glass transition temperature and thermal decomposition temperature. The wear rate of PPS surfaces was reduced three times when 5wt% boehmite was incorporated into the PPS. During exposure for 15 days at 300 C, the PPS underwent hydrothermal oxidation, leading to the substitution of sulfide linkages by the sulfite linkages. However, such molecular alteration did not significantly diminish the ability of the coating to protect carbon steel against corrosion. In fact, PPS coating filled with boehmite of {le} 5wt% adequately mitigated its corrosion in brine at 300 C. One concern in using this filler was that it absorbs brine. Thus, adding an excess amount of boehmite was detrimental to achieving the maximum protection afforded by the coatings.

  10. Effect of diffusion on coating microstructure and oxidation resistance of aluminizing steel

    Institute of Scientific and Technical Information of China (English)

    夏原; 于升学; 姚枚; 李铁藩

    2001-01-01

    The effect of diffuse treatment on coating microstructure and oxidation resistance at high-temperature of hotdip aluminum were studied by means of TEM, SEM and XRD. The results show that, the diffusion temperature has significant effect on structure of coatings and its oxidation resistance. After diffusion at 750 ℃, the coating consists of thick outer surface layer (Fe2Al5+FeAl2 ), thin internal layer (FeAl+stripe FeAl2), and its oxidation resistance is poor. After diffusion at 950 ℃, the outer surface layer is composed of single FeAl2 phase, the internal layer is composed of FeAl phase, and its oxidation resistance declines due to the occurrence of early stage internal oxidation cracks in the coating.After diffusion at 850 ℃, the outer surface layer becomes thinner and consists of FeAl2+Fe2Al5 (small amount), the internal layer becomes thicker and consists of FeAl+spherical FeAl2, and the spheroidized FeAl2 phase in the internal layer and its existing in FeAl phase steadily improve the oxidation resistance of the coating.

  11. Residual stress and wear resistance of WC particle reinforced Ni-based coating%W C颗粒增强 Ni基涂层的残余应力及耐磨性能

    Institute of Scientific and Technical Information of China (English)

    郭华锋; 李菊丽; 孙涛; 杨海峰

    2014-01-01

    Microstructure of WC particle reinforced Ni-based plasma-sprayed coating was observed by scanning electron microscope (SEM). Surface residual stress of the coating with different WC content and the bonding layer were tested by X -ray diffraction ( XRD) method. Microhardness and wear mechanism of the coating were studied by friction and wear test machine and confocal laser scanning microscope .The results show that the surface residual stress of the coatings are compressive stress and decreased with the increase of WC content .However, residual stress increase with the increase of thickness of coatings and when thickness is 1000 μm, the coating appears delamination failure . The thermal stress is the largest contributive factor to residual stress of the bonding layer .A certain amplitude of compressive stress is beneficial to improve abrasion resistance of the coating .The wear loss of the coating is only about 0.135 times of that of the substrate under the same loading .The wear mechanism of the coating is mainly abrasive wear .%用扫描电子显微镜( SEM)观察了等离子喷涂WC颗粒增强Ni涂层的显微结构,用X射线衍射法( XRD)测试了不同WC含量下涂层及粘结层表面残余应力,利用摩擦磨损试验机和共聚焦激光扫描显微镜研究了涂层的磨损机制。结果表明:涂层表面残余应力为压应力,且随着WC含量的增加先增大后减小,随着涂层厚度的增加而增大,厚度为1000μm时出现分层失效,热应力对粘结层残余应力的贡献最大。一定幅值的压应力有利于涂层耐磨性的提高,同载荷下磨损量仅为基体的0.135倍,涂层磨损机制主要为磨粒磨损。

  12. Sand-wear resistance of brush electroplated nanocomposite coating in oil and its application to remanufacturing

    Institute of Scientific and Technical Information of China (English)

    DONG Shi-yun; XU Bin-shi; DU Ling-zhong; YANG Hua

    2005-01-01

    Sand-wear resistance of nano scale alumina particle reinforced nickel matrix composite coating (n-Al2O3/ Ni) prepared by brush electroplating technique was investigated via wear tests in sand-contaminated oil lubricant,comparing with that of AISI1045 steel and brush electroplated Ni coating. Effects of testing load, sand content and sand size on worn volume of the three materials, and also coating surface roughness on worn volume of the brush electroplated coatings were accessed. Results show that the worn volume of all the three materials increases with increasing of testing load, sand content and sand size. In the same conditions, n-Al2 O3/Ni composite coating has the smallest worn volume while AISI1045 steel has the largest because of the n-Al2 O3 particle effects. As to n-Al2 O3/Ni and Ni coatings, the surface-polished coatings have obviously lower worn volume than the as-plated coatings. The brush electroplated n-Als O3/Ni composite coating was employed to remanufacture the sand-worn bearing seats of a heavy vehicle and good results were gained.

  13. Mechanical Properties and Corrosion Resistance of HVOF Sprayed Coatings Using Nanostructured Carbide Powders

    Directory of Open Access Journals (Sweden)

    Żórawski W.

    2016-12-01

    Full Text Available Nanostructured and composite WC-12Co coatings were prepared by means of the supersonic spray process (HVOF. The microstructure and composition of WC-12Co nanostructured powder were analyzed by scanning electron microscope (SEM and transmission electron microscope (TEM. Investigations revealed nano grains of WC with the size in the range of 50-500 nm. The nanostructured sprayed coating was analysed by SEM and phase composition was investigated by X-ray diffractometer (XRD. A denser coating structure with higher hardness was observed compared to conventional coating with a small amount of W2C, WC1−x, W and some amorphous phase. Young’s modulus and hardness were determined by depth sensing indentation in HVOF sprayed WC-12Co nanostructured coatings. Results were compared to conventional coatings and the relevance of the nanostructure was analyzed. An indentation size effect was observed on the polished surface and cross-section of both coatings. Data provided by indentation tests at maximum load allow to estimate hardness and elastic modulus. Enhanced nanomechanical properties of conventional coating in comparison to nanostructured one were observed. Nanostructured coatings WC-12Co (N revealed significantly better corrosion resistance.

  14. Structure, morphology and corrosion resistance of Ni–Mo+PTh composite coatings

    Indian Academy of Sciences (India)

    J Niedbała

    2015-06-01

    Ni–Mo+PTh composite coatings were prepared from nickel–molybdenum galvanic bath with the addition of thiophene (Th) and HClO4 as result of two processes: induced Ni–Mo alloy deposition and PTh polymerization. A scanning electron microscope was used for surface morphology characterization of the coatings. The Scanning ElectrochemicalWorkstationM370 was used to the surface map of the tested composite coatings. The chemical composition of the coatings was determined by the energy-dispersive spectroscopy (EDS) method. It was stated that the surface of the coatings are characterized by the presence of Ni–Mo particles and polythiophene agglomerates. Electrochemical corrosion investigations of coatings were carried out in the 5 M KOH solution, using voltammetry and electrochemical impedance spectroscopy (EIS) methods. On the basis of these research works it was found that the composite Ni–Mo+PTh coatings are more corrosion resistant in alkaline solution than Ni–Mo. The reasons for this are the presence of the polymer on the surface of the coatings and a decrease of corrosion active surface area of the coatings.

  15. Oxidation resistance of iron and copper foils coated with reduced graphene oxide multilayers.

    Science.gov (United States)

    Kang, Dongwoo; Kwon, Jee Youn; Cho, Hyun; Sim, Jae-Hyoung; Hwang, Hyun Sick; Kim, Chul Su; Kim, Yong Jung; Ruoff, Rodney S; Shin, Hyeon Suk

    2012-09-25

    Protecting the surface of metals such as Fe and Cu from oxidizing is of great importance due to their widespread use. Here, oxidation resistance of Fe and Cu foils was achieved by coating them with reduced graphene oxide (rG-O) sheets. The rG-O-coated Fe and Cu foils were prepared by transferring rG-O multilayers from a SiO(2) substrate onto them. The oxidation resistance of these rG-O-coated metal foils was investigated by Raman spectroscopy, optical microscopy, and scanning electron microscopy after heat treatment at 200 °C in air for 2 h. The bare metal surfaces were severely oxidized, but the rG-O-coated metal surfaces were protected from oxidation. This simple solution process using rG-O is one advantage of the present study.

  16. Microstructure and Corrosion Resistance of Aluminium and Copper Composite Coatings Deposited by LPCS Method

    Directory of Open Access Journals (Sweden)

    Winnicki M.

    2016-12-01

    Full Text Available The paper presents the study of microstructure and corrosion resistance of composite coatings (Al+Al2O3 and Cu+Al2O3 deposited by Low Pressure Cold Spraying method (LPCS. The atmospheric corrosion resistance was examined by subjecting the samples to cyclic salt spray and Kesternich test chambers, with NaCl and SO2 atmospheres, respectively. The selected tests allowed reflecting the actual working conditions of the coatings. The analysis showed very satisfactory results for copper coatings. After eighteen cycles, with a total time of 432 hours, the samples show little signs of corrosion. Due to their greater susceptibility to chloride ions, aluminium coatings have significant corrosion losses.

  17. Blanching resistant Cu-Cr coating by vacuum plasma spray

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, K.T. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.; Krotz, P.D. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.; Yuen, J.L. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.

    1995-11-01

    Copper alloy rocket engine combustion chamber linings have been found to deteriorate when exposed to cyclic reducing oxidizing (redox) environments, which are a consequence of the combustion process. The deterioration, known as blanching, can be characterized by increased roughness and burn-through sites in the wall of the combustion chamber lining and can seriously reduce the operational lifetime of the combustion chamber. A Cu-30 vol.%Cr coating produced by vacuum plasma spraying was effective in protecting the copper alloy substrate against blanching. The coating properties were characterized after cyclic oxidation exposure to 650 C in air followed by high pressure hydrogen charging. When exposed to an oxidizing environment at high temperatures, the coating formed a protective chromia scale that was substantially unreduced by high pressure hydrogen. (orig.)

  18. Anti-abrasive nanocoatings current and future applications

    CERN Document Server

    2015-01-01

    This book provides an overview of the fabrication methods for anti-abrasive nanocoatings. The connections among fabrication parameters, the characteristics of nanocoatings and the resulting properties (i.e. nanohardness, toughness, wear rate, load-bearing ability, friction coefficient, and scratch resistance) are discussed. Size-affected mechanical properties of nanocoatings are examined, including their uses. Anti-abrasive nanocoatings, including metallic-, ceramic-, and polymeric-based layers, as well as different kinds of nanostructures, such as multi-layered nanocomposites and thin films, are reviewed. * Provides a comprehensive overview of the fabrication methods for anti-abrasive nanocoatings* Discusses the connections among fabrication parameters, the characteristics of nanocoatings and the resulting properties* Reviews advantages and drawbacks of fabrication methods for anti-abrasive nanocoatings and clarifies the place of these nanocoatings in the world of nanotechnology

  19. Development of coatings with improved corrosion resistance in sulfur-containing environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. (Argonne National Lab., IL (USA)); Johnson, R.N. (Westinghouse Hanford Co., Richland, WA (USA))

    1990-01-01

    Corrosion of metallic structure materials at elevated temperatures in complex multicomponent gas environments is a potential problem in many fossil energy systems, especially those using coal as a feedstock. The use of appropriate corrosion-resistant coatings on metallic components can minimize material degradation and extend component life. In the present study, the chemical compatibility of a number of coatings is examined by exposing them to simulated oxygen/sulfur mixed-gas environments at metal temperatures of 500 and 650{degree}C. Coatings were developed via pack cementation and electrospark deposition techniques on T22 and T91 substrates. The oxidation/sulfidation test results for the coated specimens were compared with those for the uncoated alloys and for high-chromium structural alloys of interest in fossil energy applications. Coatings tested were Fe--Cr--Mo. Alloys tested include nickel base, nickel, and chromium alloys, and stainless steel 310. 5 refs., 12 figs., 2 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Anil V. Virkar

    2006-12-31

    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 {approx}0.05 S/cm at 800 C. For a 5 micron coating, this equates to a maximum {approx}0.025 {Omega}cm{sup 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{sub 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 {approx}1 micron in thickness. From these studies, it was projected that a 5 micron coating would be sufficient to ensure 40,000 h life.

  1. A durability test rig and methodology for erosion-resistant blade coatings in turbomachinery

    Science.gov (United States)

    Leithead, Sean Gregory

    A durability test rig for erosion-resistant gas turbine engine compressor blade coatings was designed, completed and commissioned. Bare and coated 17-4PH steel V103-profile blades were rotated at up to 11500 rpm and impacted with Garnet sand for 5 hours at an average concentration of 2.51 gm3of air , at a blade leading edge Mach number of 0.50. The rig was determined to be an acceptable first stage axial compressor representation. Two types of 16 microm-thick coatings were tested: Titanium Nitride (TiN) and Chromium-Aluminum-Titanium Nitride (CrAlTiN), both applied using an Arc Physical Vapour Deposition technique at the National Research Council in Ottawa, Canada. A Leithead-Allan-Zhao (LAZ) score was created to compare the durability performance of uncoated and coated blades based on mass-loss and blade dimension changes. The bare blades' LAZ score was set as a benchmark of 1.00. The TiN-coated and CrAlTiN-coated blades obtained LAZ scores of 0.69 and 0.41, respectively. A lower score meant a more erosion-resistant coating. Major modes of blade wear included: trailing edge, leading edge and the rear suction surface. Trailing edge thickness was reduced, the leading edge became blunt, and the rear suction surface was scrubbed by overtip and recirculation zone vortices. It was found that the erosion effects of vortex flow were significant. Erosion damage due to reflected particles was not present due to the low blade solidity of 0.7. The rig is best suited for studying the performance of erosion-resistant coatings after they are proven effective in ASTM standardized testing. Keywords: erosion, compressor, coatings, turbomachinery, erosion rate, blade, experimental, gas turbine engine

  2. Realizing of the process approach to quality management of wear resistant coatings

    OpenAIRE

    МЄДВЄДЄВА, Н. А.; Національний авіаційний університет

    2016-01-01

    A process-oriented model of technological process of wear-resistant coatings by electrocontactstrengthening of sprayed coatings (ECSSC) during the recovery machine parts is proposed. Itsstructural description has allowed to reproduce the process approach in conformity with internationalstandard ISO 9001:2015. Also, visual and more formalized presentation of interactionof the quality management system with technological process, working environment and thedynamics of its implementation was don...

  3. The corrosion resistance of zinc coatings in the presence of boron-doped detonation nanodiamonds (DND)

    Science.gov (United States)

    Burkat, G. K.; Alexandrova, G. S.; Dolmatov, V. Yu; Osmanova, E. D.; Myllymäki, V.; Vehanen, A.

    2017-02-01

    The effect of detonation nanodiamonds, doped with boron (boron-DND) in detonation synthesis on the process of zinc electrochemical deposition from zincate electrolyte is investigated. It is shown that the scattering power (coating uniformity) increases 2-4 times (depending on the concentration of DND-boron electrolyte conductivity does not change, the corrosion resistance of Zn- DND -boron coating increases 2.6 times in 3% NaCl solution (corrosion currents) and 3 times in the climatic chamber.

  4. Stability and Normal Zone Propagation Speed in YBCO Coated Conductors with Increased Interfacial Resistance (PREPRINT)

    Science.gov (United States)

    2010-03-01

    AFRL-RZ-WP-TP-2010-2085 STABILITY AND NORMAL ZONE PROPAGATION SPEED IN YBCO COATED CONDUCTORS WITH INCREASED INTERFACIAL RESISTANCE...August 2006 – 25 August 2008 4. TITLE AND SUBTITLE STABILITY AND NORMAL ZONE PROPAGATION SPEED IN YBCO COATED CONDUCTORS WITH INCREASED INTERFACIAL...reproduce, release, perform, display, or disclose the work. 14. ABSTRACT We will discuss how stability and speed of normal zone propagation in YBCO

  5. Protective coatings on extensible biofibres

    Science.gov (United States)

    Holten-Andersen, Niels; Fantner, Georg E.; Hohlbauch, Sophia; Waite, J. Herbert; Zok, Frank W.

    2007-09-01

    Formulating effective coatings for use in nano- and biotechnology poses considerable technical challenges. If they are to provide abrasion resistance, coatings must be hard and adhere well to the underlying substrate. High hardness, however, comes at the expense of extensibility. This property trade-off makes the design of coatings for even moderately compliant substrates problematic, because substrate deformation easily exceeds the strain limit of the coating. Although the highest strain capacity of synthetic fibre coatings is less than 10%, deformable coatings are ubiquitous in biological systems. With an eye to heeding the lessons of nature, the cuticular coatings of byssal threads from two species of marine mussels, Mytilus galloprovincialis and Perna canaliculus, have been investigated. Consistent with their function to protect collagenous fibres in the byssal-thread core, these coatings show hardness and stiffness comparable to those of engineering plastics and yet are surprisingly extensible; the tensile failure strain of P. canaliculus cuticle is about 30% and that of M. galloprovincialis is a remarkable 70%. The difference in extensibility is attributable to the presence of deformable microphase-separated granules within the cuticle of M. galloprovincialis. The results have important implications in the design of bio-inspired extensible coatings.

  6. Development of a Long-Life-Cycle, Highly Water-Resistant Solar Reflective Retrofit Roof Coating

    Energy Technology Data Exchange (ETDEWEB)

    Polyzos, Georgios [ORNL; Hunter, Scott Robert [ORNL; Sharma, Jaswinder K [ORNL; Cheng, Mengdawn [ORNL; Chen, Sharon S [Lawrence Berkeley National Laboratory (LBNL); Demarest, Victoria [Dow Chemical Company; Fabiny, William [Dow Chemical Company; Destaillats, Hugo [Lawrence Berkeley National Laboratory (LBNL); Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL)

    2016-03-04

    Highly water-resistant and solar-reflective coatings for low-slope roofs are potentially among the most economical retrofit approaches to thermal management of the building envelope. Therefore, they represent a key building technology research program within the Department of Energy. Research efforts in industry and the Department of Energy are currently under way to increase long-term solar reflectance on a number of fronts. These include new polymer coatings technologies to provide longer-lasting solar reflectivity and improved test methodologies to predict long-term soiling and microbial performance. The focus on long-term improvements in soiling and microbial resistance for maximum reflectance does not address the single most important factor impacting the long-term sustainability of low-slope roof coatings: excellent water resistance. The hydrophobic character of asphaltic roof products makes them uniquely suitable for water resistance, but their low albedo and poor exterior durability are disadvantages. A reflective coating that maintains very high water resistance with increased long-term resistance to soiling and microbial activity would provide additional energy savings and extend roof service life.

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

    Science.gov (United States)

    Farmer, Joseph C.

    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.

  8. FORMATION OF HIGHLY RESISTANT CARBIDE AND BORIDE COATINGS BY A TWO-STAGE DEPOSITION METHOD

    Directory of Open Access Journals (Sweden)

    W. I. Sawich

    2011-01-01

    Full Text Available A study was made of the aspects of forming highly resistant coatings in the surface zone of tool steels and solid carbide inserts by a two-stage method. at the first stage of the method, pure Ta or Nb coatings were electrodeposited on samples of tool steel and solid carbide insert in a molten salt bath containing Ta and Nb fluorides. at the second stage, the electrodeposited coating of Ta (Nb was subjected to carburizing or boriding to form carbide (TaC, NbC or boride (TaB, NbB cladding layers.

  9. Radiation-Resistant Hybrid Lotus Effect for Achieving Photoelectrocatalytic Self-Cleaning Anticontamination Coatings

    Science.gov (United States)

    Taylor, Edward W.; Pirich, Ronald G.

    2011-01-01

    An experiment involving radiation-resistant hydrophobic coatings is planned for space exposure and experimental testing on the International Space Station (ISS) in 2011. The Lotus biocide coatings are designed for supporting space exploration missions. This innovation is an antibacterial, anti-contamination, and self-cleaning coating that uses nano-sized semiconductor semimetal oxides to neutralize biological pathogens and toxic chemicals, as well as to mitigate dust accumulation (see figure). The Lotus biocide coating is thin (approximately microns thick), lightweight, and the biocide properties will not degrade with time or exposure to biological or chemical agents. The biocide is stimulated chemically (stoichiometric reaction) through exposure to light (photocatalysis), or by an applied electric field (electrocatalysis). The hydrophobic coating samples underwent preliminary high-energy proton and alpha-ray (helium ion) irradiations at the Lawrence Berkeley National Laboratory 88" cyclotron and demonstrated excellent radiation resistance for a portion of the Galactic Cosmic Ray (GRC) and Solar Proton spectrum. The samples will undergo additional post-flight studies when returned to Earth to affirm further the radiation resistance properties of the space exposed coatings.

  10. Ethanol-resistant ethylcellulose/guar gum coatings--importance of formulation parameters.

    Science.gov (United States)

    Rosiaux, Y; Velghe, C; Muschert, S; Chokshi, R; Leclercq, B; Siepmann, F; Siepmann, J

    2013-11-01

    Recently, ethylcellulose/guar gum blends have been reported to provide ethanol-resistant drug release kinetics from coated dosage forms. This is because the ethanol insoluble guar gum effectively avoids undesired ethylcellulose dissolution in ethanol-rich bulk fluids. However, so far the importance of crucial formulation parameters, including the minimum amount of guar gum to be incorporated and the minimum required guar gum viscosity, remains unclear. The aim of this study was to identify the most important film coating properties, determining whether or not the resulting drug release kinetics is ethanol-resistant. Theophylline matrix cores were coated in a fluid bed with blends of the aqueous ethylcellulose dispersion "Aquacoat®ECD30" and guar gum. The polymer blend ratio, guar gum viscosity, and degree of dilution of the final coating dispersion were varied. Importantly, it was found that more than 5% guar gum (referred to the total polymer content) must be incorporated in the film coating and that the apparent viscosity of a 1% aqueous guar gum solution must be greater than 150 cP to provide ethanol-resistance. In contrast, the investigated degree of coating dispersion dilution was not found to be decisive for the ethanol sensitivity. Furthermore, all investigated formulations were long term stable, even upon open storage under stress conditions for 6 months.

  11. Biocorrosion resistance of coated magnesium alloy by microarc oxidation in electrolyte containing zirconium and calcium salts

    Science.gov (United States)

    Wang, Ya-Ming; Guo, Jun-Wei; Wu, Yun-Feng; Liu, Yan; Cao, Jian-Yun; Zhou, Yu; Jia, De-Chang

    2014-09-01

    The key to use magnesium alloys as suitable biodegradable implants is how to adjust their degradation rates. We report a strategy to prepare biocompatible ceramic coating with improved biocorrosion resistance property on AZ91D alloy by microarc oxidation (MAO) in a silicate-K2ZrF6 solution with and without Ca(H2PO4)2 additives. The microstructure and biocorrosion of coatings were characterized by XRD and SEM, as well as electrochemical and immersion tests in simulated body fluid (SBF). The results show that the coatings are mainly composed of MgO, Mg2SiO4, m-ZrO2 phases, further Ca containing compounds involve the coating by Ca(H2PO4)2 addition in the silicate-K2ZrF6 solution. The corrosion resistance of coated AZ91D alloy is significantly improved compared with the bare one. After immersing in SBF for 28 d, the Si-Zr5-Ca0 coating indicates a best corrosion resistance performance.

  12. The effects of manganese phosphate coating wear resistance of chilled ductile iron camshafts

    Directory of Open Access Journals (Sweden)

    Tarık Gün

    2013-06-01

    Full Text Available The ductile iron camshafts are preferred due to high toughness and strength features in the automobile industry. Through the coolants used in the camshaft production high surface hardness is achieved. In this study, the wear resistance effects of ductile iron chill produced camshafts coated with manganese phosphate are researched. The camshaft surfaces produced as ductile iron chill are coated with manganese phosphate. The coating surfaces are observed with scanning electron microscope (SEM. The changes occurring on the cam profiles are measured with running the wear resistance of the manganese phosphate coating on the camshafts on the engine test rig with 30 minutes interval in 1000rpm. In order to compare the results of uncoated camshafts run on engines are checked against simultaneously. As result, the manganese phosphate coated cams were 2,8 times less worn up than the uncoated cams. The manganese phosphate coated ductile iron chill camshafts are less worn up according to uncoated camshafts because of the oil holding feature of manganese phosphate coating.

  13. [Effect of titanium nitride coating on bacterial corrosion resistance of dental Co-Cr alloy].

    Science.gov (United States)

    Zou, Jie; Chen, Jie; Hu, Bin

    2010-04-01

    To study the influence of titanium nitride(TiN) coating on bacterial corrosion resistance of clinically used Co-Cr alloy. The Co-Cr alloy commonly used for casting metal full crown was casted with specimen 10mm x 10mm x 3mm in size. The specimen was coated with a thickness of 2.5 microm TiN coating on the surface by multi-arc physical vapor deposition. Then the specimen before and after coating titanium nitride were exposed to TSB media with S.mutans or Actinomyces viscosus,while pure media,as control.After inoculated for 24 hours, the Tafel polarization curves of the specimen were measured by electrochemical station. From the Tafel polarization curves, the non-coated Co-Cr alloy showed that corrosion potential moved to the negative way in presence of oral bacteria,and passivation interval got shorter.While the polarization curves of the specimen after coating TiN changed slightly in presence of oral microorganism. The TiN significantly weakened the corrosion action of bacteria on the alloy. These results demonstrate that the TiN coating with better tolerance to the bacterial action can improve bacterial corrosion resistance of Co-Cr alloy.Supported by Research Fund of Science and Technology Commission of Shanghai Municipality(Grant No.08DZ2271100) and Shanghai Leading Academic Discipline Project (Grant No. S30206).

  14. Fatigue resistant carbon coatings for rolling/sliding contacts

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Harpal; Ramirez, Giovanni; Eryilmaz, Osman; Greco, Aaron; Doll, Gary; Erdemir, Ali

    2016-06-01

    The growing demands for renewable energy production have recently resulted in a significant increase in wind plant installation. Field data from these plants show that wind turbines suffer from costly repair, maintenance and high failure rates. Often times the reliability issues are linked with tribological components used in wind turbine drivetrains. The primary failure modes in bearings and gears are associated with micropitting, wear, brinelling, scuffing, smearing and macropitting all of which occur at or near the surface. Accordingly, a variety of surface engineering approaches are currently being considered to alter the near surface properties of such bearings and gears to prevent these tribological failures. In the present work, we have evaluated the tribological performance of compliant highly hydrogenated diamond like carbon coating developed at Argonne National Laboratory, under mixed rolling/sliding contact conditions for wind turbine drivetrain components. The coating was deposited on AISI 52100 steel specimens using a magnetron sputter deposition system. The experiments were performed on a PCS Micro-Pitting-Rig (MPR) with four material pairs at 1.79 GPa contact stress, 40% slide to roll ratio and in polyalphaolefin (PAO4) basestock oil (to ensure extreme boundary conditions). The post-test analysis was performed using optical microscopy, surface profilometry, and Raman spectroscopy. The results obtained show a potential for these coatings in sliding/rolling contact applications as no failures were observed with coated specimens even after 100 million cycles compared to uncoated pair in which they failed after 32 million cycles, under the given test conditions.

  15. Electrodeposition of high corrosion resistance Cu/Ni-P coating on AZ91D magnesium alloy

    Science.gov (United States)

    Zhang, Shan; Cao, Fahe; Chang, Linrong; Zheng, JunJun; Zhang, Zhao; Zhang, Jianqing; Cao, Chunan

    2011-08-01

    High corrosion resistance Cu/Ni-P coatings were electrodeposited on AZ91D magnesium alloy via suitable pretreatments, such as one-step acid pickling-activation, once zinc immersion and environment-friendly electroplated copper as the protective under-layer, which made Ni-P deposit on AZ91D Mg alloy in acid plating baths successfully. The pH value and current density for Ni-P electrodeposition were optimized to obtain high corrosion resistance. With increasing the phosphorous content of the Ni-P coatings, the deposits were found to gradually transform to amorphous structure and the corrosion resistance increased synchronously. The anticorrosion ability of AZ91D Mg alloy was greatly improved by the amorphous Ni-P deposits, which was investigated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The corrosion current density ( Icorr) of the coated Mg alloy substrate is about two orders of magnitude less than that of the uncoated.

  16. Study of coatings for improved fire and decay resistance of mine timbers

    Science.gov (United States)

    Baum, B.

    1977-01-01

    The purpose of this program was to find a fire- and rot-retardant polymer/fungicide reaction product for coating mine timbers. Fire-retardant polymers were screened as films and coatings on fir wood. Curable polyimide appeared to be flame retardant and evolved a minimum of fumes when exposed to a flame. Several organic and metal, low toxicity, fungicides were reacted with the polyimide in-situ on the wood. These coated samples were screened for fungus resistance. All formulations rated well - even the polyimide film without additives was fungicidal. The fir wood control itself resisted internal damage during the ten weeks of fungus exposure. A more severe test for fungus resistance will be required.

  17. An excellent ozone-resistant polymethylvinylsiloxane coating on natural rubber by thiol-ene click chemistry

    Directory of Open Access Journals (Sweden)

    N. Y. Ning

    2015-06-01

    Full Text Available Natural rubber (NR as renewable resource is a kind of cheap and versatile elastomer. A disadvantage of NR is that the ozone resistance is not good, which needs to be improved for its wider application. In this study, polymethylvinylsiloxane (PMVS coating on natural rubber (NR was realized for the first time by using thiol-ene click reaction under UV irradiation, simultaniously realizing the fast crosslinking of PMVS layer and the covalent crosslinking between PMVS layer and NR layer. As a result, a good interphase adhesion between PMVS coating and NR was obtained. The coating of the crosslinked PMVS layer on NR resulted in an obvious increase in the ozone resistance of NR. Our study provides a new and high efficient strategy to prepare elastomer materials with good ozone resistance.

  18. Abrasion of ultrafine WC-Co by fine abrasive particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Abrasive wear of a series of WC-(5%-14%, mass fiaction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used.The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage.This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

  19. Extended Functionality of Environmentally-Resistant Mo-Si-B-Based Coatings

    Science.gov (United States)

    Perepezko, J. H.; Sakidja, R.

    2013-02-01

    Multiphase Mo-Si-B alloys with compositions which yield the ternary intermetallic Mo5SiB2 (T2) phase as a key microstructure constituent together with the Mo and Mo3Si phases, offer an attractive balance of high melting temperature, oxidation resistance, and mechanical properties. The investigation of reaction kinetics involving the T2 phase enables the analysis of oxidation in terms of diffusion pathways and the design of effective coatings. From this basis, kinetic biasing is used together with pack cementation to develop Mo-Si-B-based multilayered coatings with an aluminoborosilica surface and in situ diffusion barriers with self-healing characteristics for enhanced oxidation resistance. While a combustion environment contains water vapor that can accelerate an attack of silica-based coatings, the Mo-Si-B-based coatings provide oxidation resistance in water vapor up to at least 1,500°C. An exposure to hot ionized gas species generated in an arc jet confirms the robust coating performance in extreme environments. To extend the application beyond Mo-based systems, a two-stage process has been implemented to provide effective oxidation resistance for refractory metal cermets, SiC and ZrB2 ultra-high-temperature composites.

  20. Preparation and Corrosion Resistance of Rare Earth Conversion Coatings on AZ91 Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    Xu Yue; Chen Xiang; Lü Zushun; Li Yingjie

    2005-01-01

    The feasibility of forming pollution-free and environmentally benign Ce-based rare earth conversion coatings (short for RECCs) on AZ91 magnesium alloy to enhance corrosion resistance was studied. The effect of optimum processing parameters on corrosion resistance of RECCs, such as density of treating solution, temperature and time of coating formation were discussed. Protective performance of conversion coatings on magnesium alloy was evaluated by moisture/heating test, anodic polarization, etc. The results show that Ce-based RECCs under moisture/heating condition can remain intact, with high coverage and no obvious corrosion phenomenon. Corrosion potential increases and passive phenomenon occurs while current density decreases, therefore Ce-based RECCs can improve corrosion resistance of AZ91 magnesium alloy. The morphology of Ce-based RECCs prepared under optimum process through SEM observation is found to be a few particles coherent to the base coating, and the coating has no cracks and exhibits apparent corrosion resistance during corrosion courses of AZ91 magnesium alloy.

  1. Progress in Research on Vanadate-Based Coatings on Corrosion Resistance

    Institute of Scientific and Technical Information of China (English)

    Zou Zhongli; Li Ning; Li Deyu

    2007-01-01

    Vanadate, usually used as the corrosion resistant inhibitor for the paint systems, is one of the substances that have been proposed as alternative to toxic chromate for the corrosion protection. In this paper, the possibility of vanadate passivating from its chemical properties was introduced firstly. Then, the progress and examples in research on vanadate conversion coatings on the corrosion resistance were summarized. And the substrates discussed here contained aluminum alloys, magnesium alloys and so on. Finally, the research tendency of vanadate-based coatings was discussed.

  2. Corrosion Resistance of 304L SS Spray Coated with Zirconia Nanoparticles

    Science.gov (United States)

    Maheswari, A. Uma; Sivakumar, M.; Indhumathi, N.; Mohan, Sreedevi R.

    2016-09-01

    Influence of substrate temperature on corrosion (in 3.5% NaCl) and wear resistance of nanostructured zirconia thin film coated 304L SS substrates are studied by electrochemical and nano-indentation methods. This analysis shows 304L SS substrate spray coated with nanostructured zirconia at substrate temperature closer to the boiling point of the spray solvent ethanol exhibited good corrosion and wear resistance behaviour. This is because of the compressive stress developed during film fabrication at lower substrate temperature (∼50 °C) and hence constrains the indentation plasticity, which leads to higher indentation load than the bare 304L SS.

  3. Dwindling the resistance value of PEDOT:PSS - coated on fabric yarns

    Science.gov (United States)

    Amba Sankar K., N.; Mohanta, Kallol

    2016-05-01

    Herein we describe by dip coating method to transform typical fabric yarn to conductive fiber. Different types of yarns have been used to coat from a known conductive polymer, Poly (3,4ethylenedioxythiophene) Poly (styrene sulfonic acid). We have optimized the method to have lesser resistance of the conductive yarns. The minimum resistance achieved has a value of 77 Ω/cm. This value is not high as metals but could be comparable to that of metal oxides or semiconducting materials. However, flexibility of yarns and feeling of fabric combining with the conductivity developed in this process is suitable for wearable electronics and also as gas sensors, electromagnetic shielding.

  4. Dwindling the resistance value of PEDOT:PSS – coated on fabric yarns

    Energy Technology Data Exchange (ETDEWEB)

    Amba Sankar, K.N., E-mail: amb@psgias.ac.in; Kallol, Mohanta [Nanotechnology Research, Innovation & Incubation Centre, Organic Solar cell lab, PSG Institute of Advanced Studies, Coimbatore – 641 004, Tamilnadu (India)

    2016-05-23

    Herein we describe by dip coating method to transform typical fabric yarn to conductive fiber. Different types of yarns have been used to coat from a known conductive polymer, Poly (3,4ethylenedioxythiophene) Poly (styrene sulfonic acid). We have optimized the method to have lesser resistance of the conductive yarns. The minimum resistance achieved has a value of 77 Ω/cm. This value is not high as metals but could be comparable to that of metal oxides or semiconducting materials. However, flexibility of yarns and feeling of fabric combining with the conductivity developed in this process is suitable for wearable electronics and also as gas sensors, electromagnetic shielding.

  5. A process for the production of a scale-proof and corrosion-resistant coating on graphite and carbon bodies

    Science.gov (United States)

    Fitzer, E.

    1981-01-01

    A process for the production of a corrosion resistant coating on graphite and carbon bodies is described. The carbon or graphite body is coated or impregnated with titanium silicide under the addition of a metal containing wetting agent in a nitrogen free atmosphere, so that a tight coating is formed.

  6. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles

    Science.gov (United States)

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-02-01

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air.

  7. Plasma electrolytic oxidation coating on AZ91 magnesium alloy modified by neodymium and its corrosion resistance

    Science.gov (United States)

    Song, Y. L.; Liu, Y. H.; Yu, S. R.; Zhu, X. Y.; Wang, Q.

    2008-03-01

    Ceramic coatings on the surfaces of Mg-9Al-1Zn (AZ91) magnesium alloy and Mg-9Al-1Zn-1Nd magnesium alloy (AZ91 magnesium alloy modified by neodymium, named as AZ91Nd in this paper) are synthesized in aluminate electrolyte by plasma electrolytic oxidation (PEO) process, respectively. X-ray diffraction and X-ray photoelectron spectroscopy analyses show the PEO coating on the Mg-9Al-1Zn-1Nd alloy comprises not only MgO and Al 2O 3, which are found in the coating on the AZ91 alloy, but also a trace amount of Nd 2O 3. Microstructure observations indicate the addition of Nd can decrease the sizes of β phases and form Al 2Nd intermetallics in the AZ91 alloy. The fine β phases can effectively restrain the formation of unclosed-holes and greatly decrease the sizes of pores in the coating during the PEO process. In addition, the Al 2Nd intermetallics can be completely covered due to the lateral growth of the PEO coatings formed on the α and β phases. As a result, the coating on the AZ91Nd alloy possesses a dense microstructure compared with that on the AZ91 alloy. The following corrosion tests indicate the corrosion resistance of the PEO coating on the AZ91Nd alloy is evidently higher than that of the PEO coating on the AZ91 alloy.

  8. Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles.

    Science.gov (United States)

    Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

    2016-02-02

    A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air.

  9. Patching for corneal abrasion.

    Science.gov (United States)

    Lim, Chris H L; Turner, Angus; Lim, Blanche X

    2016-07-26

    Published audits have demonstrated that corneal abrasions are a common presenting eye complaint. Eye patches are often recommended for treating corneal abrasions despite the lack of evidence for their use. This systematic review was conducted to determine the effects of the eye patch when used to treat corneal abrasions. The objective of this review was to assess the effects of patching for corneal abrasion on healing and pain relief. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to May 2016), System for Information on Grey Literature in Europe (OpenGrey) (January 1995 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 9 May 2016. We also searched the reference lists of included studies, unpublished 'grey' literature and conference proceedings and contacted pharmaceutical companies for details of unpublished trials. We included randomised and quasi-randomised controlled trials that compared patching the eye with no patching to treat simple corneal abrasions. Two authors independently assessed the risk of bias and extracted data. Investigators were contacted for further information regarding the quality of trials. The primary outcome was healing at 24, 48 and 72 hours while secondary outcomes included measures of pain, quality of life and adverse effects. We graded the certainty of the evidence using GRADE. We included 12 trials which

  10. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2007-03-31

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the hightemperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several 409 low alloy steel samples after coating them in our fluidized bed reactor and also after exposing them to our corrosion test. We report the following findings: 1. A protective coating was deposited inside a porous 409 steel sample to protect it from sulfidation attack. The coating was based on a combination of Si diffusion layer, Nb interlayer and nitrides of titanium and silicon. 2. Analysis of solid coupons exposed to simulated coal gas at 900 C for 300 h showed that multilayer metal/ceramic coatings provide a better protection than ceramic coatings. 3. Deposition of several ceramic/metal multilayer coatings showed that coatings with niobium and tantalum interlayers have good adhesion. However, coatings with a tungsten interlayer suffered localized delaminating and coatings with Zr interlayers showed poor adhesion. 4. Analysis of solid coupons, coated with the above-mentioned multilayer films, after exposure to simulated coal gas at 900 C for 300 h showed that niobium is the best candidate for interlayer material.

  11. Corrosion and wear resistant metallic layers produced by electrochemical methods

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1999-01-01

    Corrosion and wear-corrosion properties of novel nickel alloy coatings with promising production characteristics have been compared with conventional bulk materials and hard platings. Corrosion properties in neutral and acidic environments have been investigated with electrochemical methods....... Determination of polarisation resistance during 100 hours followed by stepwise anodic polarisation seems to be a promising technique to obtain steady state data on slowly corroding coatings with transient kinetics. A slurry test enables determination of simultaneous corrosion and abrasive wear. Comparison...

  12. Characterisation and corrosion resistance of TiN-Ni nanocomposite coatings using RBS and NRA

    Energy Technology Data Exchange (ETDEWEB)

    Noli, F., E-mail: noli@chem.auth.grl [Department of Chemistry, Aristotle University, GR-54124 Thessaloniki (Greece); Misaelides, P., E-mail: misailid@auth.gr [Department of Chemistry, Aristotle University, GR-54124 Thessaloniki (Greece); Lagoyannis, A., E-mail: lagoya@inp.demokritos.gr [Tandem Accelerator Laboratory, Nuclear Physics Institute, NCSR Demokritos, GR-15310 Aghia Paraskevi, Attiki (Greece); Akbari, A., E-mail: alireza_ak@yahoo.com [Universite de Poitiers, Laboratoire de Physique des Materiaux (PHYMAT), UMR6630-CNRS, 86960 Chasseneuil, Futuroscope Cedex (France)

    2011-12-15

    Nanocomposite TiN-Ni coatings were produced by a duplex treatment on Ti-6Al-4V substrates. The procedure consisted of plasma nitriding of the substrate followed by deposition of a TiN-Ni layer by sputtering a composite Ti-Ni target with 1.2 keV Ar{sup +} ions. The growing film was bombarded during deposition by a mixture of 50 eV Ar{sup +}-N{sup 2+}-N{sup +} ions. The temperature as well as the Ni- and the N-content of the coatings varied in order to obtain the optimum structural and mechanical properties. The surface morphology of the coatings was examined by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The results showed that Ni appears as an amorphous phase around the TiN crystallites. The thickness and the composition of the coatings were investigated by Rutherford Backscattering Spectrometry (RBS) using deuterons as projectiles. The nitrogen depth distribution in the coatings was determined by Nuclear Reaction Analysis (NRA) using {sup 14}N(d, {alpha}) and {sup 14}N(d, p) nuclear reactions. The corrosion resistance of the nitrided and non-nitrided coatings in aggressive environment (NaCl 3% solution at RT) was investigated using electrochemical techniques (potentiodynamic polarisation and cyclic voltammetry). It was found that nanocomposite coatings are stable and do not influence the corrosion resistance of the Ti-alloy substrate. The nitrided coatings exhibited higher wear and corrosion resistance related with their Ni-content.

  13. Preparation and characterization of the micro-arc oxidation composite coatings on magnesium alloys

    Directory of Open Access Journals (Sweden)

    Yanfeng Ge

    2014-12-01

    Full Text Available The magnesium alloys attract the light-weight manufacture due to its high strength to weight ratio, however the poor corrosion resistance limits the application in automobile industry. The Micro-arc Composite Ceramic (MCC coatings on AZ91D magnesium alloys were prepared by Micro-arc Oxidation (MAO and electrophoresis technologies. The microstructure, corrosion resistance, abrasion resistance, stone impact resistance and adhesion of MCC coatings were studied respectively. The cross section morphologies showed that the outer organic coating was filled into the hole on surface of MAO coating, and it acted as a shelter against corrosive products. The copper-accelerated acetic acid salt spray Test, abrasion resistance test, stone impact resistance test, thermal shock resistance test and adhesion test were used to evaluate the protective characterization by the third testing organization which approved by GM. The test results showed the composite coatings meet all the requirements. The MCC coating on Mg presents excellent properties, and it is a promising surface treatment technology on magnesium alloys for production vehicles.

  14. CORROSION RESISTANCE OF ORGANOMETALLIC COATING APLICATED IN FUEL TANKS USING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY IN BIOFUEL – PART I

    Directory of Open Access Journals (Sweden)

    Milene Adriane Luciano

    2014-10-01

    Full Text Available Nowadays, the industry has opted for more sustainable production processes, and the planet has also opted for new energy sources. From this perspective, automotive tanks with organometallic coatings as well as a partial substitution of fossil fuels by biofuels have been developed. These organometallic coated tanks have a zinc layer, deposited by a galvanizing process, formed between the steel and the organometallic coating. This work aims to characterize the organometallic coating used in metal automotive tanks and evaluate their corrosion resistance in contact with hydrated ethyl alcohol fuel (AEHC. For this purpose, the resistance of all layers formed between Zinc and EEP steel and also the tin coated steel, which has been used for over thirty years, were evaluated. The technique chosen was the Electrochemical Impedance Spectroscopy. The results indicated an increase on the corrosion resistance when organometallic coatings are used in AEHC medium. In addition to that, these coatings allow an estimated 25% reduction in tanks production costs.

  15. Wear resistance of Fe-Nb-Cr-W, Nb, AISI 1020 and AISI 420 coatings produced by thermal spray wire arc; Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyeccion termica por arco electrico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Covaleda, E. A.; Mercado-Veladia, J. L.; Olaya-Florez, J. J.

    2013-07-01

    The commercial materials 140MXC (with iron, tungsten, chrome, niobium), 530AS (AISI 1015 steel) and 560AS (AISI 420 steel) on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1) homogeneous coatings and (2) coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser con focal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW). We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation. (Author)

  16. Tailored Aluminium based Coatings for Optical Appearance and Corrosion Resistance

    DEFF Research Database (Denmark)

    Aggerbeck, Martin

    The current project investigated the possibility of designing aluminium based coatings focusing on the effect of composition and surface finish on the optical appearance and on the alkaline corrosion properties using titanium as the main alloying element. The main results and discussions of this ......The current project investigated the possibility of designing aluminium based coatings focusing on the effect of composition and surface finish on the optical appearance and on the alkaline corrosion properties using titanium as the main alloying element. The main results and discussions...... the optical appearance is affected by the alloy composition, surface morphology, and the microstructure. Four commercial aluminium alloys were studied before and after polishing, etching, anodisation, and hot water sealing, giving an overview on how the alloy composition affects the appearance. It was found...... that the roughness after etching increases with higher amounts of alloying elements (especially iron and silicon). Proper polishing requires some alloy hardness, while alloy purity is required for a glossy appearance after anodisation. Magnetron sputtered aluminium based coatings containing up to 18 wt. % titanium...

  17. A moisture-resistant antireflective coating by sol-gel process for neodymium-doped phosphate laser glass

    Institute of Scientific and Technical Information of China (English)

    Ruijun Liu; Ruoyu Zhan; Yongxing Tang; Jianqiang Zhu

    2006-01-01

    @@ Using methyl triethoxysilicane as precursor, a moisture-resistant coating for neodymium-doped laser glass was developed by the sol-gel process. Colloidal silica was added in coating solution as modifier. The refractive index of this coating varied from 1.31 to 1.42. A porous antireflective (AR) silica coating with the index of 1.27 was coated on the moisture-resistant coating surface. The two-layer coating possessed transmission up to 99.1% at wavelength of 966 nm, surface root-mean-square (RMS) roughness of 1.245nm, and roughness of average (RA) of 0.961 nm. In the case of laser of 1053-nm laser wavelength and 1-ns pulse duration, the damage threshold of the two-layer coatings was more than 15 J/cm2.

  18. Surface morphology and corrosion resistance of electrodeposited composite coatings containing polyethylene or polythiophene in Ni–Mo base

    Indian Academy of Sciences (India)

    J Niedbała

    2011-07-01

    Ni–Mo + PENi and Ni–Mo + PTh composite coatings have been prepared by nickel-molybdenum deposition from a bath containing a suspension of PENi or Th. These coatings were obtained at galvanostatic conditions, at a current density of dep = – 0.100 A cm-2 and temperature of 293 K. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS. Electrochemical corrosion resistance investigations were carried out in 5 M KOH, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found, that the composite coatings containing thiophene are more corrosion resistant in alkaline solution than the Ni–Mo + PENi coatings. This is caused by presence of the polymer on the coatings surface and decrease of corrosion active surface area of the coatings.

  19. Corrosion resistance and development length of steel reinforcement with cementitious coatings

    Science.gov (United States)

    Pei, Xiaofei

    This research program focused on the corrosion resistance and development length of reinforcing steel coated with Cementitious Capillary Crystalline Waterproofing (CCCW) materials. The first part of this research program involved using the half-cell potential method to evaluate the corrosion resistance of CCCW coating materials. One hundred and two steel bars were embedded in concrete cylinders and monitored. In total, 64 steel reinforcing bars were coated with CCCW prior to embedment, 16 mortar cylinders were externally coated with CCCW, and 22 control (uncoated) samples were tested. All the samples were immersed in a 3.5% concentration chloride solution for a period of one year. Three coating types were studied: CCCW-B, CCCW-B+ C and CCCW-C+D. The test results showed that the CCCW coating materials delayed the corrosion activity to varying degrees. In particular, CCCW-C+D applied on the reinforcing steel surface dramatically delayed the corrosion activity when compared to the control samples. After being exposed to the chloride solution for a period of one year, no sign of corrosion was observed for the cylinders where the concrete surface was coated. The second part of this research evaluated the bond strength and development length of reinforcing steel coated with two types of CCCW coating materials (CCCW-B+C and CCCW-C+D) using a modified pull-out test method. A self-reacting inverted T-shaped beam was designed to avoid compression in the concrete surrounding the reinforcing steel. Steel reinforcing bars were embedded along the web portion of the T-beam with various embedded lengths and were staggered side by side. In total, six T-beams were fabricated and each beam contained 8 samples. Both short-term (7 days) and long-term (3 months) effects of water curing were evaluated. The reinforcing steel bars coated with CCCW-B+C demonstrated a higher bond strength than did samples coated with CCCW-C+D. However, the bond strengths of samples with coating materials

  20. Wear Resistance of Piston Sleeve Made of Layered Material Structure: MMC A356R, Anti-Abrasion Layer and FGM Interface

    Directory of Open Access Journals (Sweden)

    Hernik Szymon

    2016-09-01

    Full Text Available The aim of this paper is the numerical analysis of the one of main part of car engine – piston sleeve. The first example is for piston sleeve made of metal matrix composite (MMC A356R. The second improved material structure is layered. Both of them are comparison to the classical structure of piston sleeve made of Cr-Ni stainless steel. The layered material structure contains the anti-abrasion layer at the inner surface of piston sleeve, where the contact and friction is highest, FGM (functionally graded material interface and the layer of virgin material on the outer surface made of A356R. The complex thermo-elastic model with Archard's condition as a wear law is proposed. The piston sleeve is modelling as a thin walled cylindrical axisymmetric shell. The coupled between the formulation of thermo-elasticity of cylindrical axisymmetric shell and the Archard’s law with functionally changes of local hardness is proposed.

  1. HF粉煤灰混凝土的力学变形及抗冲磨性能试验研究%Experimental Research on HF Fly Ash Concrete Mechanical Deformation and Abrasion Resistance

    Institute of Scientific and Technical Information of China (English)

    张建博; 杜应吉

    2012-01-01

    quantity of increase in HF anti-abrasion agent, its ab- rasion resistance is greatly improved, the compressive strength of concrete is also improved, but the matching water-binder ratio is considered in improving the mixed quantity of HF anti-abrasion agent to increase HF concrete strength, which can result in the utility of HF anti-abrasion agent to play out better to the effect of concrete strength; according to different periods of fly ash contents on the mechanical properties and durability of concrete performance influence law, when HF fly ash concrete's design age is 90d, fly ash content should be 25% less than 30. As water hinder ratio decreases in a certain range, concrete compressive strength, the ulti- mate tensile strain, tensile elastic modulus of axis, tensile strength, compressive elastic modulus of axis, compressive strength, anti -abrasion strengths are improved regularly.

  2. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2006-12-31

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several coated and exposed samples of 409 steel by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX), and report on the findings of four samples: (1) Analysis of two porous coupons after exposure to the porous metal particulate filter of the coal gasification power plant at 370 C for 2140 hours revealed that corrosion takes place in the bulk of the sample while the most external zone surface survived the test. (2) Coating and characterization of several porous 409 steel coupons after being coated with nitrides of Ti, Al and/or Si showed that adjusting experimental conditions results in thicker coatings in the bulk of the sample. (3) Analysis of coupons exposed to simulated coal gas at 370 C for 300 hours showed that a better corrosion resistance is achieved by improving the coatings in the bulk of the samples.

  3. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    Science.gov (United States)

    Cheng, Feng; Jiang, Shuyun

    2014-02-01

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (-200 V/80 A, labeled DLC-1, and -100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  4. Enhanced biocorrosion resistance and biocompatibility of degradable Mg-Nd-Zn-Zr alloy by brushite coating.

    Science.gov (United States)

    Niu, Jialin; Yuan, Guangyin; Liao, Yi; Mao, Lin; Zhang, Jian; Wang, Yongping; Huang, Feng; Jiang, Yao; He, Yaohua; Ding, Wenjiang

    2013-12-01

    To further improve the corrosion resistance and biocompatibility of Mg-Nd-Zn-Zr alloy (JDBM), a biodegradable calcium phosphate coating (Ca-P coating) with high bonding strength was developed using a novel chemical deposition method. The main composition of the Ca-P coating was brushite (CaHPO4·2H2O). The bonding strength between the coating and the JDBM substrate was measured to be over 10 MPa, and the thickness of the coating layer was about 10-30 μm. The in vitro corrosion tests indicated that the Ca-P treatment improved the corrosion resistance of JDBM alloy in Hank's solution. Ca-P treatment significantly reduced the hemolysis rate of JDBM alloy from 48% to 0.68%, and induced no toxicity to MC3T3-E1 cells. The in vivo implantation experiment in New Zealand's rabbit tibia showed that the degradation rate was reduced obviously by the Ca-P treatment and less gas was produced from Ca-P treated JDBM bone plates and screws in early stage of the implantation, and at least 10weeks degradation time can be prolonged by the present coating techniques. Both Ca-P treated and untreated JDBM Mg alloy induced bone growth. The primary results indicate that the present Ca-P treatment is a promising technique for the degradable Mg-based biomaterials for orthopedic applications.

  5. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feng; Jiang, Shuyun, E-mail: jiangshy@seu.edu.cn

    2014-02-15

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (−200 V/80 A, labeled DLC-1, and −100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  6. Microstructure and Erosion Resistance Performance of ZrAlN/Cu Coating

    Science.gov (United States)

    Du, Jun; Zhu, Xiaoying; Zhang, Ping; Cai, Zhihai

    ZrAlN/Cu coating has been deposited onto Ti-6Al-4 V substrate by reactive magnetron sputtering in order to improve its erosion resistance. The morphology and microstructure were studied combined with Field Emission Scanning Electron Microscrope(FSEM), X-ray Diffraction(XRD), X-ray Photoelectron Spectroscopy(XPS) and Transmission Electron Microscopy(TEM). Coatings hardness and toughness were measured by nano-indentation method and Vicker indentation method respectively. It has been found that Zr0.79Al0.19Cu0.02N coating possess dense columnar structure with 20∼40 nm columnar grains exbibiting (100) preferential orientation. XRD reflection peaks slightly shifts to higher angle, showing some of 19at%Al and 2at%Cu substitutely dissolves into face-centered cubic(FCC) ZrN lattice, XPS proves the existence of AlN and Cu phase in coating. Zr0.79Al0.19Cu0.02N coating demonstrates best erosion resistance at 15°∼90° impingement angle compared with Ti6Al4 V substrate, ZrN and Zr0.80Al0.20N coating, attributing to combination of high hardness(40.7 GPa) and good toughness.

  7. RESEARCH ABOUT RESULTS REPRODUTIBILITY AND ABRASIVE PARTICLES FRAGMENTATION IN BALL-CRATERING TESTS

    Directory of Open Access Journals (Sweden)

    Ronaldo Câmara Cozza

    2013-06-01

    Full Text Available The micro-abrasive wear tests by rotating ball (crater wear have played an important role in abrasive wear researches. In this type of test, the contact between a specimen and a ball on rotating motion and abrasive particles supplied between these two elements, results in a crater on the specimen, based on which the abrasive wear behaviour is analysed. The purpose of this work is to study results the reprodutibility and the silicon carbide (SiC abrasive particles fragmentation during micro-abrasive wear tests. Tests were conducted with carburized AISI 1010 steel balls and high speed steel specimens, “with” and “without” titanium nitride (TiN coatings. The abrasive slurry was prepared with black silicon carbide (average particle size of 5 µm and distilled water. Grooving abrasion is related with lower reprodutibility results. For the test conditions of this work, no abrasive particles fragmentation was observed, independently of the sliding distance, what is justified, among others factors, by the low normal force applied.

  8. Improvement of Microhardness and Corrosion Resistance of Stainless Steel by Nanocomposite Coating

    OpenAIRE

    Hiba Husam Ismail; Kareem Neamah Sallomi; Hamid S. Mahdi

    2014-01-01

    Stainless steel (AISI 304) has good electrical and thermal conductivities, good corrosion resistance at ambient temperature, apart from these it is cheap and abundantly available; but has good mechanical properties such as hardness. To improve the hardness and corrosion resistance of stainless steel its surface can be modified by developing nanocomposite coatings applied on its surface. The main objective of this paper is to study effect of electroco-deposition method on microhardness and cor...

  9. Comparison of surface fractal dimensions of chromizing coating and P110 steel for corrosion resistance estimation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Naiming, E-mail: lnmlz33@163.com [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Guo, Junwen [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Xie, Faqin [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Zou, Jiaojuan; Tian, Wei [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Yao, Xiaofei [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Zhang, Hongyan; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2014-08-30

    Highlights: • Continuous chromizing coating was synthesized on P110 steel by pack cementation. • The chromizing coating showed better corrosion resistance. • Comparison of surface fractal dimensions can estimate corrosion resistance. - Abstract: In the field of corrosion research, mass gain/loss, electrochemical tests and comparing the surface elemental distributions, phase constitutions as well as surface morphologies before and after corrosion are extensively applied to investigate the corrosion behavior or estimate the corrosion resistance of materials that operated in various environments. Most of the above methods are problem oriented, complex and longer-period time-consuming. However from an object oriented point of view, the corroded surfaces of materials often have self-similar characterization: fractal property which can be employed to efficiently achieve damaged surface analysis. The present work describes a strategy of comparison of the surface fractal dimensions for corrosion resistance estimation: chromizing coating was synthesized on P110 steel surface to improve its performance via pack cementation. Scanning electron microscope (SEM) was used to investigate the surface morphologies of the original and corroded samples. Surface fractal dimensions of the detected samples were calculated by binary images related to SEM images of surface morphologies with box counting algorithm method. The results showed that both surface morphologies and surface fractal dimensions of P110 steel varied greatly before and after corrosion test, but the chromizing coating changed slightly. The chromizing coating indicated better corrosion resistance than P110 steel. Comparison of surface fractal dimensions of original and corroded samples can rapidly and exactly realize the estimation of corrosion resistance.

  10. Corrosion resistance of Ni–Co alloy and Ni–Co/SiC nanocomposite coatings electrodeposited by sediment codeposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Bakhit, Babak, E-mail: b_bakhit@sut.ac.ir [Surface Engineering Group, Advanced Materials Research Center, Faculty of Materials Engineering, Sahand University of Technology, PO Box 51335-1996, Tabriz (Iran, Islamic Republic of); Akbari, Alireza; Nasirpouri, Farzad [Surface Engineering Group, Advanced Materials Research Center, Faculty of Materials Engineering, Sahand University of Technology, PO Box 51335-1996, Tabriz (Iran, Islamic Republic of); Hosseini, Mir Ghasem [Electrochemistry Research Laboratory, Department of Physical Chemistry, Chemistry Faculty, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2014-07-01

    Corrosion resistance of Ni–Co alloy and Ni–Co/SiC nanocomposite coatings electrodeposited in a modified Watts bath using sediment codeposition (SCD) technique was evaluated by potentiodynamic polarization measurements in the 3.5% NaCl solution and studied as a function of deposition conditions In order to characterize the morphology, chemical and phase compositions of the coatings, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray diffraction (XRD) were utilized, respectively. It was observed that the cobalt content in the Ni–Co alloy coatings was increased through an anomalous behavior by increasing the cobalt concentration in the electrolyte. The highest percentage of SiC nano-particles (8.1 vol.%) in the Ni–Co/SiC nanocomposite coatings was achieved at 3 A/dm{sup 2} deposition current density and 5 g/l particle concentration. SEM and EDS analysis illustrated that SiC nano-particles were distributed uniformly throughout the nanocomposite coatings. The potentiodynamic polarization tests indicated that the corrosion resistance of the Ni–Co alloy coatings was varied as a function of the cobalt content, and the corrosion resistance of the Ni–Co/SiC nanocomposite coatings was markedly higher than the corrosion resistance of the Ni–Co alloy coatings. Among the studied coatings, Ni–Co/SiC nanocomposite coatings containing 8.1 vol.% SiC nano-particles exhibited the best corrosion resistance.

  11. Effect of Pyrrole and N-Methylpyrrole Coatings on Corrosion Resistance of Mild Steel

    Institute of Scientific and Technical Information of China (English)

    AliAshrafi; M.A.Golozarl; S.Mallakpour; AliGhasemi

    2004-01-01

    Electrochemical polymerizations of various ratios of pyrrole and methylpyrrole monomers were performed in aqueous toluene-4-sulfinic acid sodium salt (T4SNa) electrolyte, using galvanostatic method, pH of electrolyte was adjusted by p-toluene sulfonic acid (PTSA). In order to prevent corrosion of mild steel substrates during coating deposition, specimens were pretreated in 0.5M oxalic acid solution, employing galvanostatic method. This would passivate the steel substrate and facilitate the coating process as well. Corrosion resistance of coated substrates was investigated in 1M NaCl solution using Tafel polarization technique. In addition, using scanning electron microscopy (SEM), morphological characterization of coatings produced, was investigated. Regarding the corrosion characteristics, results obtained revealed that the ratio of 1 to 1(Pyrrole/Methylpyrrole) could play an important role.

  12. Effect of Pyrrole and N-Methylpyrrole Coatings on Corrosion Resistance of Mild Steel

    Institute of Scientific and Technical Information of China (English)

    Ali Ashrafi; M.A.Golozar; S.Mailakpour; Ali Ghasemi

    2004-01-01

    Electrochemical polymerizations of various ratios of pyrrole and methylpyrrole monomers were performed in aqueous toluene-4-sulfinic acid sodium salt (T4SNa) electrolyte, using galvanostatic method. pH of electrolyte was adjusted by p-toluene sulfonic acid (PTSA). In order to prevent corrosion of mild steel substrates during coating deposition,specimens were pretreated in 0.5M oxalic acid solution, employing galvanostatic method. This would passivate the steel substrate and facilitate the coating process as well. Corrosion resistance of coated substrates was investigated in 1M NaCl solution using Tafel polarization technique. In addition, using scanning electron microscopy (SEM), morphological characterization of coatings produced, was investigated. Regarding the corrosion characteristics, results obtained revealed that the ratio of 1 to 1 (Pyrrole/Methylpyrrole) could play an important role.

  13. Development of coatings with improved corrosion resistance in sulfur-containing environments. [Fe-Cr-Mo

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. (Materials and Components Tech. Div., Argonne National Lab., IL (USA)); Johnson, R.N. (Hanford Engineering Development Lab., Westinghouse Hanford Co., Richland, WA (USA))

    1990-12-10

    Corrosion of metallic structural materials at elevated temperatures in complex multicomponent gas environments is a potential problem in many fossil energy systems, especially those using coal as a feedstock. The use of appropriate corrosion-resistant coatings on metallic components offers an avenue to minimize material degradation and to extend component life. In the present study, the chemical compatibility of a number of coatings is examined by exposing them to simulated oxygen-sulfur mixed gas environments at metal temperatures of 500 and 650degC. Coatings were developed via pack cementation and electrospark deposition techniques on T22 and T91 substrates. The oxidation-sulfidation test results obtained for the coated specimens were compared with those for the uncoated alloys as well as other high chromium structural alloys of interest in fossil energy applications. (orig.).

  14. Abrasion Properties of Steel Fiber Reinforced Silica Fume Concrete According to Los Angeles and Water Abrasion Tests

    OpenAIRE

    Tsan-Ching CHENG; Cheng, An; Ran HUANG; Lin, Wei-Ting

    2014-01-01

    The current study mainly investigated the influence of different tests on the abrasion resistance of concrete mixed with steel fibers and silica fume. The abrasion resistance was assessed at 28, 56 and 91 days on concretes with water-binder ratios of 0.35 and 0.55 where in some mixes silica fume was substituted by 5 % of cement by weight. Steel fibers of 0.5 % and 1.0 % of concrete volume were also added into the test concrete by replacement of coarse and fine aggregates. The results showed t...

  15. Comparative investigation on HVOF sprayed carbide-based coatings

    Science.gov (United States)

    Xie, Mingxiang; Zhang, Shihong; Li, Mingxi

    2013-05-01

    In this work, WC-17Co, WC-10Co-4Cr, WC-12Co and Cr3C2-25NiCr coatings were deposited on stainless steel using WOKAStar-640 HVOF spraying system. Three WC-based coatings were studied and compared with a chromium carbide-based coating. The microstructure, porosity, micro-hardness, indentation fracture toughness and adhesion strength of the coatings were investigated. The wear test was done by using silica grits as abrasive medium using a load of 20 N. The result shows that HVOF sprayed carbide-based coating possesses low porosity, high micro-hardness and high adhesion strength. Three WC-based coatings have higher micro-hardness and indentation fracture toughness compared to the Cr3C2-25NiCr coating. HVOF sprayed carbide coating has good wear resistance under 500 °C. The decarburization of WC-based coating has great effect on coating wear resistance. In addition, WC-17Co coating has best wear resistance.

  16. Engineering meter-scale laser resistant coatings for the near IR

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J; Adams, J J; Shirk, M D; Norton, M A; Weiland, T L

    2005-08-26

    Laser resistant coatings are needed for beam steering (mirrors), pulse switching (polarizers), and high transport efficiency on environmental barriers (windows/lenses) on large laser systems. A range of defects limit the exposure fluence of these coatings. By understanding the origin and damage mechanisms for these defects, the deposition process can be optimized to realize coatings with greater laser resistance. Electric field modeling can provide insight into which defects are most problematic. Laser damage growth studies are useful for determining a functional laser damage criteria. Mitigation techniques such as micro-machining with a single-crystal diamond cutting tool or short pulse laser ablation using the burst technique can be used to arrest growth in damage sites to extend optic lifetime.

  17. Biodegradation-Resistant Multilayers Coated with Gold Nanoparticles. Toward a Tailor-made Artificial Extracellular Matrix.

    Science.gov (United States)

    Prokopović, Vladimir Z; Vikulina, Anna S; Sustr, David; Duschl, Claus; Volodkin, Dmitry

    2016-09-21

    Polymer multicomponent coatings such as multilayers mimic an extracellular matrix (ECM) that attracts significant attention for the use of the multilayers as functional supports for advanced cell culture and tissue engineering. Herein, biodegradation and molecular transport in hyaluronan/polylysine multilayers coated with gold nanoparticles were described. Nanoparticle coating acts as a semipermeable barrier that governs molecular transport into/from the multilayers and makes them biodegradation-resistant. Model protein lysozyme (mimics of ECM-soluble signals) diffuses into the multilayers as fast- and slow-diffusing populations existing in an equilibrium. Such a composite system may have high potential to be exploited as degradation-resistant drug-delivery platforms suitable for cell-based applications.

  18. Steam oxidation resistant coatings for steam turbine components: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Agueero, A.; Garcia de Blas, J.; Muelas, R.; Sanchez, A.; Tsipas, S. [Instituto de Tecnica Aeroespacial, Madrid (Spain). Area de Materiales

    2001-07-01

    The principal objective of the COST Action 522 is to raise the operating temperatures of both gas and steam turbines in order to increase their efficiency to reduce fuel consumption and emissions. Concerning steam turbines, the operating temperature is expected to rise from 550 C to 650 C, and the use of oxidation resistant coatings is being considered for the first time in Europe. In this preliminary work, two deposition techniques have so far been explored: slurry paints and atmospheric plasma spray (APS). Commercially available materials, known to have good oxidation resistance, were selected for both deposition techniques: one aluminium slurry and three alloyed materials for thermal spray: AlFe, FeCrAl and NiAl. The coatings were characterised by SEM-EDS and steam oxidation testing was carried out at 650 C. The preliminary findings show that some of the studied coatings may offer adequate protection. (orig.)

  19. Corrosion Resistance of a Sand Particle-Modified Enamel Coating Applied to Smooth Steel Bars

    Directory of Open Access Journals (Sweden)

    Fujian Tang

    2014-09-01

    Full Text Available The protective performance of a sand particle-modified enamel coating on reinforcing steel bars was evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy (EIS. Seven percentages of sand particles by weight were investigated: 0%, 5%, 10%, 20%, 30%, 50% and 70%. The phase composition of the enamel coating and sand particles were determined with the X-ray diffraction (XRD technique. The surface and cross-sectional morphologies of the sand particle-modified enamel coating were characterized using scanning electron microscopy (SEM. XRD tests revealed three phases of sand particles: SiO2, CaCO3 and MgCO3. SEM images demonstrated that the enamel coating wetted well with the sand particles. However, a weak enamel coating zone was formed around the sand particles due to concentrated air bubbles, leading to micro-cracks as hydrogen gas pressure builds up and exceeds the tensile strength of the weak zone. As a result, the addition of sand particles into the enamel coating reduced both the coating and corrosion resistances.

  20. 钢渣高性能混凝土抗冲耐磨性能试验%Study on the abrasion resistant properties of high performance concrete with steel slag powder

    Institute of Scientific and Technical Information of China (English)

    信玉良; 侍克斌; 努尔开力·依孜特罗甫; 吴福飞

    2014-01-01

    In order to use a large amount of industrial waste more efficiently, 15 groups of concrete specimens with different contents of steel slag powder ( SSP) were designed and produced. An experimental study with a special emphasizes on the influence of SSP contents on the workability, mechanical properties, and abrasion resistance of concrete was carried out. The test results showed that the workability of concrete could be improved by steel slag powder, and in the different water glue ratio, the early strength of concrete with steel slag powder is less than the reference concrete. When the dosage of steel slag is within 10%-30%, the late strength of concrete with steel slag powder is approximately equal or slightly higher than the reference concrete. While the dosage of steel slag is greater than 30%, the late strength of concrete decreased greatly. In this experiment, the concrete's anti-abrasion strength of 28 day is tested by high-speed under water method. The results show that anti abrasion strength of concrete with steel slag powder increases slightly than the benchmark concrete when the steel slag content within 10%. When the steel slag is greater than 20%, the anti-abrasion strength of concrete decreased. Therefore, when the steel slag poses as admixture of concrete, the volume should be controlled within 20%.%为有效利用大宗废料钢渣,设计制作了15组掺钢渣粉混凝土试件,试验研究钢渣粉掺量对混凝土的工作性能、力学性能及抗冲耐磨性能的影响极其作用机理。结果表明:钢渣粉可以改善混凝土的工作性能;在不同水胶比下,掺钢渣粉混凝土的早期强度均小于基准混凝土,钢渣掺量在10%~30%以内时,混凝土的后期强度与基准混凝土基本持平,且略有提高,钢渣掺量大于30%时混凝土的后期强度下降较大;采用水下钢球法测试混凝土28 d抗冲磨强度,得出钢渣掺量在10%以内时混凝土的抗冲磨强度比基准混凝

  1. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    Science.gov (United States)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  2. Applications in the Nuclear Industry for Corrosion-Resistant Amorphous-Metal Thermal-Spray Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Choi, J

    2007-07-18

    Amorphous metal and ceramic thermal spray coatings have been developed that can be used to enhance the corrosion resistance of containers for the transportation, aging and disposal of spent nuclear fuel and high-level radioactive wastes. Fe-based amorphous metal formulations with chromium, molybdenum and tungsten have shown the corrosion resistance believed to be necessary for such applications. Rare earth additions enable very low critical cooling rates to be achieved. The boron content of these materials, and their stability at high neutron doses, enable them to serve as high efficiency neutron absorbers for criticality control. Ceramic coatings may provide even greater corrosion resistance for container applications, though the boron-containing amorphous metals are still favored for criticality control applications. These amorphous metal and ceramic materials have been produced as gas atomized powders and applied as near full density, non-porous coatings with the high-velocity oxy-fuel process. This paper summarizes the performance of these coatings as corrosion-resistant barriers, and as neutron absorbers. Relevant corrosion models are also discussed, as well as a cost model to quantify the economic benefits possible with these new materials.

  3. Wear-resistant ball bearings for space applications. [coated with titanium carbide

    Science.gov (United States)

    Boving, H.; Hintermann, H. E.; Haenni, W.; Bondivenne, E.; Boeto, M.; Conde, M.

    1977-01-01

    Ball bearings for hostile environments were developed. They consist of normal ball bearing steel parts of which the rings are coated with hard, wear-resistant, chemical vapor deposited (C.V.D) TiC. Experiments in ultrahigh vacuum, using cages of various materials with self-lubricating properties, have shown that such bearings are suitable for space applications.

  4. Effect of plasma nitriding and titanium nitride coating on the corrosion resistance of titanium.

    Science.gov (United States)

    Wang, Xianli; Bai, Shizhu; Li, Fang; Li, Dongmei; Zhang, Jing; Tian, Min; Zhang, Qian; Tong, Yu; Zhang, Zichuan; Wang, Guowei; Guo, Tianwen; Ma, Chufan

    2016-09-01

    The passive film on the surface of titanium can be destroyed by immersion in a fluoridated acidic medium. Coating with titanium nitride (TiN) may improve the corrosion resistance of titanium. The purpose of this in vitro study was to investigate the effect of duplex treatment with plasma nitriding and TiN coating on the corrosion resistance of cast titanium. Cast titanium was treated with plasma nitriding and TiN coating. The corrosion resistance of the duplex-treated titanium in fluoride-containing artificial saliva was then investigated through electrochemical and immersion tests. The corroded surface was characterized by scanning electron microscopy (SEM) with energy-dispersive spectroscopy surface scan analysis. The data were analyzed using ANOVA (α=.05) RESULTS: Duplex treatment generated a dense and uniform TiN film with a thickness of 4.5 μm. Compared with untreated titanium, the duplex-treated titanium displayed higher corrosion potential (Ecorr) values (Pplasma nitriding and TiN coating significantly improved the corrosion resistance of cast titanium in a fluoride-containing environment. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  5. Corrosion resistant Zn–Co alloy coatings deposited using saw-tooth current pulse

    Indian Academy of Sciences (India)

    S Yogesha; A Chitharanjan Hegde

    2011-12-01

    Micro/nanostructured multilayer coatings of Zn–Co alloy were developed periodically on mild steel from acid chloride bath. Composition modulated multilayer alloy (CMMA) coatings, having gradual change in composition (in each layer) were developed galvanostatically using saw-tooth pulses through single bath technique (SBT). CMMA coatings were developed under different conditions of cyclic cathode current densities (CCCDs) and number of layers, and their corrosion resistances were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) method. Optimal configuration, represented as (Zn–Co)2.0/4.0/300 was found to exhibit ∼ 89 times better corrosion resistance compared to monolithic (Zn–Co)3.0 alloy deposited for same time, from same bath. The better corrosion resistance of CMMA coatings was attributed to changed interfacial dielectric properties, evidenced by dielectric spectroscopy. Improved corrosion resistance was attributed to formation of -type semiconductor film at the interface, supported by the Mott–Schottky plot. Further, the formation of multilayer and corrosion mechanism was analysed using scanning electron microscopy (SEM).

  6. Effect of the deposition temperature on corrosion resistance and biocompatibility of the hydroxyapatite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Vladescu, A., E-mail: alinava@inoe.ro [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Braic, M. [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Azem, F. Ak [Dokuz Eylul University, Engineering Faculty, Metallurgical and Materials Engineering Department, Buca-Izmir (Turkey); Titorencu, I. [Institute of Cellular Biology and Pathology Nicolae Simionescu of the Romanian Academy, 8 B.P.Hasdeu, Bucharest (Romania); Braic, V. [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Pruna, V. [Institute of Cellular Biology and Pathology Nicolae Simionescu of the Romanian Academy, 8 B.P.Hasdeu, Bucharest (Romania); Kiss, A. [National Institute for Optoelectronics, 409 Atomistilor Str., Magurele (Romania); Parau, A.C.; Birlik, I. [Dokuz Eylul University, Engineering Faculty, Metallurgical and Materials Engineering Department, Buca-Izmir (Turkey)

    2015-11-01

    Highlights: • Hydroxyapatite has been produced at temperature from 400 to 800 °C by magnetron sputtering. • Hydroxyapatite crystallinity is improved by increasing substrate temperature. • The increase of substrate temperature resulted in corrosion resistance increasing. • The coating shows high growth of the osteosarcoma cells over a wide temperature range. - Abstract: Hydroxyapatite (HAP) ceramics belong to a class of calcium phosphate-based materials, which have been widely used as coatings on titanium medical implants in order to improve bone fixation and thus to increase the lifetime of the implant. In this study, HAP coatings were deposited from pure HAP targets on Ti6Al4V substrates using the radio-frequency magnetron sputtering technique at substrate temperatures ranging from 400 to 800 °C. The surface morphology and the crystallographic structure of the films were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion resistance of the coatings in saliva solution at 37 °C was evaluated by potentiodynamic polarization. Additionally, the human osteosarcoma cell line (MG-63) was used to test the biocompatibility of the coatings. The results showed that all of the coatings grown uniformly and that the increasing substrate temperature induced an increase in their crystallinity. Corrosion performance of the coatings was improved with the increase of the substrate temperature from 400 °C to 800 °C. Furthermore, all the coatings support the attachment and growth of the osteosarcoma cells with regard to the in vitro test findings.

  7. Improved thermal stability and oxidation resistance of Al–Ti–N coating by Si addition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Li, E-mail: chenli_927@126.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Zhuzhou Cemented Carbide Cutting Tools Co., LTD, Zhuzhou 412007 (China); Yang, Bing; Xu, Yuxiang; Pei, Fei [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Zhou, Liangcai [Institute of Materials Science and Technology, Vienna University of Technology, Vienna A1040 (Austria); Du, Yong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

    2014-04-01

    Addition of Si is very effective in upgrading the machining performance and thermal properties of Al–Ti–N coating. Here, we concentrate on the thermal stability and oxidation resistance of Al–Ti–Si–N coating. Alloying with Si favors the growth of wurtzite phase, and thereby causes a drop in hardness from ∼ 34.5 to 28.7 GPa. However, Si-containing coating retards the formation of w-AlN during thermal annealing, and thereby behaves a high hardness value of ∼ 31.3 GPa after annealing at T{sub a} = 1100 °C. After 10 h exposure in air at 850 °C, Al–Ti–N coating is fully oxidized. Incorporation of Si significantly improves the oxidation resistance of Al–Ti–N due to the combined effects with the promoted formation of Al-oxide rich top-scale and retarded transformation of anatase (a-) TiO{sub 2} into rutile (r-) TiO{sub 2}, where only ∼ 1.43 μm oxide scale is shown after oxidation at 1100 °C for 15 h. Noticeable is that the worst oxidation resistance of Al–Ti–Si–N coating in the temperature range from 800 to 1100 °C is obtained at 950 °C with oxide scale of ∼ 1.76 μm due to the fast formation of r-TiO{sub 2}. Additionally, a pre-oxidation at 1000 °C has a positive effect on the oxidation resistance of Al–Ti–Si–N coating, which is attributed to the formation of Al-oxide rich top-scale, and thus inhibits the outward diffusion of metal atoms and inward diffusion of O. - Highlights: • Si as a substitutional solid solution and via the formation of a-Si{sub 3}N{sub 4} coexists. • Si addition favors the growth of wurtzite phase and causes a decreased hardness. • Alloying with Si improves the oxidation resistance of AlTiN. • AlTiSiN behaves the worst oxidation resistance at 950 °C from 800 to 1100 °C. • A pre-oxidation at 1000 °C improves the oxidation resistance of AlTiSiN coating.

  8. Abrasive wear and surface roughness of contemporary dental composite resin.

    Science.gov (United States)

    Han, Jian-min; Zhang, Hongyu; Choe, Hyo-Sun; Lin, Hong; Zheng, Gang; Hong, Guang

    2014-01-01

    The purpose of this study was to evaluate the abrasive wear and surface roughness of 20 currently available commercial dental composite resins, including nanofilled, supra-nanofilled, nanohybrid and microhybrid composite resins. The volume loss, maximum vertical loss, surface roughness (R(a)) and surface morphology [Scanning electron microscopy (SEM)] were determined after wear. The inorganic filler content was determined by thermogravimetric analysis. The result showed that the volume loss and vertical loss varied among the materials. The coefficients of determination (R(2)) of wear volume loss and filler content (wt%) was 0.283. SEM micrographs revealed nanofilled composites displayed a relatively uniform wear surfaces with nanoclusters protrusion, while the performance of nanohybrid composites varied. The abrasive wear resistance of contemporary dental composite resins is material-dependent and cannot be deduced from its category, filler loading and composite matrix; The abrasive wear resistance of some flowable composites is comparable to the universal/posterior composite resins.

  9. [The effect on anti-acid corrosion resistance of Ni-Cr alloy coating titanium].

    Science.gov (United States)

    Hu, Bin; Zhang, Fu-qiang

    2003-04-01

    The aim of this study was to investigate the variation of the corrosion resistance of Ni-Cr alloy in acid environment before and after coating titanium in vitro. 1. Surface treatment using sol-gel technique of coating titanium. The steps were as follows: (1) Pre-treatment: sanding, washing and activation in order to remove the oxidative product; (2) The preparation of sol: some small charged particles produced by the hydrolytic reaction, and formed sol. These particles would congeal into extremely small ones (diameter usually is 5 microns); (3) Coating; (4) Heat treatment: The organism was resolved and volatilizeed at high temperature, and the atoms of Ti were left. These atoms of Ti were very active and could combine firmly with the atoms on the surface awaiting of treatment. 2. artificial saliva; pH = 7.0 and pH = 5.6; temperature: 36.5 degrees C 3. Electrochemical test: polarization curve; instrument: ZF-3 poteniostat. Before coating titanium, when pH was 7.0, the electrode potential of Ni-Cr alloy was -160 mV, and the self-corrosion current density was 0.262 microA cm-2; when pH = 5.6, the data were -182 mV and 0.352 microA cm-2, respectively. This result showed that when pH value reduced, the potential and current density descended, too. This indicated that the material was easy to be corroded. After coating titanium, when pH value was 7.0, the potential was -71 mV, the self-corrosion current density was 0.152 microA cm-2; when pH = 5.6, the data were -89 mV and 0.174 microA cm-2. This indicated that the corrosion rate of material descended evidently after coating titanium in acid environment. (1) Not only before coating Ti but also after coating, the corrosion resistance of Ni-Cr alloy would descend in acid environment;(2) In acid environment, the corrosion resistance of Ni-Cr alloy after coating titanium was superior to that of the material before coating. So was in neutral environment.

  10. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2006-06-30

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several coated and exposed samples of 409 steel by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). We report here on findings of this analysis: (1) A SS409 coupon that was coated with multilayered combined nitrides of Ti, Al, and Si showed adherent coatings on the surface; (2) A similarly coated coupon, after exposure to simulated coal gas at 900 C for 300 h, revealed that the coating has cracked during the exposure; (3) An SS409 coupon that was coated with nitrides of Ti and Si with a barrier layer of tungsten in between to improve the adhesion of the coating and to prevent outward diffusion of iron to the surface. (4) A porous coupon was coated with nitrides of Ti and Al and examination of the coupon revealed deposition of Ti at the interior surfaces. A similarly prepared coupon was exposed to simulated coal gas at 370 C for 300 h, and it showed no corrosion.

  11. Chemical Agent Resistant Coating Topcoat Usage: Drivers and Trends

    Science.gov (United States)

    2012-07-01

    reflectance analysis in the infrared (IR) region. CARC must also resist corrosion and degradation and removal by a decontamination solution, such as super...for Reflectance Factor and Color by Spectrophotometry Using Hemispherical Geometry. Annu. Book ASTM Stand. 2009. 7. ASTM D523. Standard Test

  12. Preparation of Phytic Acid/Silane Hybrid Coating on Magnesium Alloy and Its Corrosion Resistance in Simulated Body Fluid

    Science.gov (United States)

    Wang, Fengwu; Cai, Shu; Shen, Sibo; Yu, Nian; Zhang, Feiyang; Ling, Rui; Li, Yue; Xu, Guohua

    2017-09-01

    In order to decrease the corrosion rate and improve the bioactivity of magnesium alloy, phytic acid/saline hybrid coatings were synthesized on AZ31 magnesium alloys by sol-gel dip-coating method. It was found that the mole ratio of phytic acid to γ-APS had a great influence on coating morphology and the corresponding corrosion resistance of the coated magnesium alloys. When the mole ratio of phytic acid to γ-APS was 1:1, the obtained hybrid coating was integral and without cracks, which was ascribed to the strong chelate capability of phytic acid and Si-O-Si network derived from silane. Electrochemical test result indicated that the corrosion resistance of the coated magnesium alloy was about 27 times larger than that of the naked counterpart. In parallel, immersion test showed that the phytic acid/silane hybrid coating could induce CaP-mineralized product deposition, which offered another protection for magnesium alloy.

  13. 扫描间距对45钢激光熔凝强化组织性能的影响%Influence of scanning interval on microstructure and abrasive wear resistance of 45 Steel by laser melting

    Institute of Scientific and Technical Information of China (English)

    孙浩; 凌刚; 李洪文; 高晓丽; 姚国才

    2011-01-01

    为了研究扫描间距对45钢激光熔凝强化组织性能的影响,采用HLD1001-5型固体激光器对45钢表面进行了多条带等间距激光熔凝处理,分别利用扫描电镜、洛氏硬度计、磨损试验机观察和测量了不同扫描间距下硬化层的显微组织及性能.结果表明:激光熔凝处理的硬化层由熔化区、相变硬化区和热影响区组成,组织为马氏体:多条带等间距激光熔凝处理在垂直于熔凝条带方向上的硬度分布由左高硬度区、左过渡区、低硬度区、右过渡区和右高硬度区组成,高硬度区的硬度为58.1~59.6 HRC,低硬度区的硬度约16 HRC:在试验范围内,经激光扫描间距为4.5 mm熔凝处理的试样具有最好的耐磨性.%A variety of the multi-stripe and equal-interval laser melting treatments on the surface of 45 Steel samples were obtained using HLD1001.5 solid-state laser for studying the influence of scanning interval on the microstructure and abrasive wear resistance of 45 Steel by laser melting.The microstructure and properties of the samples were studied by SEM, Rockwell hardness tester and wear tester.The results showed that the hardened layer by laser melting was composed of melted zone, phase transformation zone and heat affected zone.The hardened layer was a martensite microstructure.The Rockwell hardness distribution was composed of left high value zone, left transitional zone, low value zone, right transitional hardness zone and right high value zone.The hardness at high value zone and low value zone was 58.1-59.6 HRC and 16 HRC respectively.Under the conditions of the experiment, the samples with the treatment of 4.5 mm scanning interval featured the best abrasive wear resistance.

  14. Electroless Ni-P-PTFE-Al2O3 Dispersion Nanocomposite Coating for Corrosion and Wear Resistance

    Science.gov (United States)

    Sharma, Ankita; Singh, A. K.

    2014-01-01

    With the aim to produce a coating having good corrosion and wear resistance alongside hardness but lesser friction coefficient, Ni-P-PTFE-Al2O3 (NiPPA) dispersion coating was developed. This was achieved by introducing nanosized polytetrafluoroethylene (PTFE) and alumina (Al2O3) in the Ni-P matrix deposited on mild steel substrate. The coating was characterized using scanning electron microscopy, energy dispersive analysis of x-ray, and x-ray diffractrometry. Microhardness and wear resistance of the coating was measured using Vicker's hardness tester and Pin-on-Disc method, respectively. The corrosion behavior was measured using electrochemical polarization and immersion tests with and without exposure in 3.5% NaCl solution. It is observed that codeposition of Al2O3 and PTFE particles with Ni-P coating results in comparatively smooth surface with nodular grains. The NiPPA coating was observed to have moderate hardness between electroless Ni-P-PTFE and Ni-P-Al2O3 coating and good wear resistance with lubricating effect. Addition of both PTFE and Al2O3 is observed to enhance corrosion resistance of the Ni-P coating. However, improvement in corrosion resistance is more due to addition of Al2O3 than PTFE. Continuous exposure for 10-20 days in corrosive solution is found to deteriorate corrosion protection properties of the coating.

  15. Contact Resistance of Tantalum Coatings in Fuel Cells and Electrolyzers using Acidic Electrolytes at Elevated Temperatures

    DEFF Research Database (Denmark)

    Jensen, Annemette Hindhede; Christensen, Erik; Barner, Jens H. Von

    2014-01-01

    Tantalum has so far been found to be the only construction material with sufficient corrosion resistance for high temperature polymer electrolyte membrane electrolyzers using acidic electrolytes above 100◦C. In this work the interfacial contact resistances of tantalum plates and tantalum coated...... stainless steel were found to be far below the US Department of Energy target value of 10mcm2. The good contact resistance of tantalum was demonstrated by simulating high temperature polymer electrolyte membrane electrolysis conditions by anodization performed in 85% phosphoric acid at 130◦C, followed...

  16. The heat resistance of a polyurethane coating filled with modified nano-CaCO3

    Science.gov (United States)

    Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei

    2014-10-01

    The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.

  17. The effect of Teflon coating on the resistance to sliding of orthodontic archwires.

    Science.gov (United States)

    Farronato, Giampietro; Maijer, Rolf; Carìa, Maria Paola; Esposito, Luca; Alberzoni, Dario; Cacciatore, Giorgio

    2012-08-01

    Teflon is an anti-adherent and aesthetic material. The aim of this study was to evaluate, in vitro, the influence of Teflon coating on the resistance to sliding (RS) of orthodontic archwires. For this purpose, Teflon-coated archwires were examined using frictional resistance tests by means of a universal testing machine and compared with conventional uncoated wires. Twelve types of archwires with round and rectangular sections (0.014, 0.018, and 0.018 × 0.025 inches) and of different materials (stainless steel and nickel-titanium) were tested with two passive self-ligating brackets (SmartClip™ and Opal(®)) and one active self-ligating bracket (Quick(®)). Each archwire-bracket combination was tested 10 times under 8 simulated clinical scenarios. Statistical comparisons were conducted between the uncoated and Teflon-coated archwires using Wilcoxon and Mann-Whitney tests, and linear regression analysis. For all bracket-archwire combinations, Teflon-coated archwires resulted lower friction than the corresponding uncoated archwires (P Teflon coating has the potential to reduce RS of orthodontic archwires.

  18. Preparation and corrosion resistance of pulse electrodeposited Zn and Zn-SiC nanocomposite coatings

    Science.gov (United States)

    Sajjadnejad, M.; Mozafari, A.; Omidvar, H.; Javanbakht, M.

    2014-05-01

    Pure Zn and Zn matrix composite coatings containing nano-sized SiC particles with an average size of 50 nm were prepared from the zinc sulfate bath. The effects of the pulse frequency, maximum current density and duty cycle on the amount of particles embedded were examined. Electron microscopic studies revealed that the coating morphology was modified by the presence of SiC nanoparticles. In the presence of SiC nanoparticles deposit grows in outgrowth mode resulting in a very rough and porous microstructure. However, at very low and very high duty cycles a smooth and pore free microstructure was obtained. Corrosion resistance properties of the coatings were studied using potentiodynamic polarization technique in 1 M NaCl solution. It was established that presence of well-dispersed nanoparticles significantly improves corrosion resistance of the zinc by filling gaps and defects between zinc flakes and leading to a smoother surface. However, presence of the SiC nanoparticles led to a mixed microstructure with fine and coarse zinc flakes in some coatings, which presented a weak corrosion behavior. Incorporation of SiC nanoparticles enhanced hardness of the Zn coatings by fining deposit structure and through the dispersion hardening effect.

  19. Corrosion Resistance of Ni/Al2O3 Nanocomposite Coatings

    Directory of Open Access Journals (Sweden)

    Beata KUCHARSKA

    2016-05-01

    Full Text Available Nickel matrix composite coatings with ceramic disperse phase have been widely investigated due to their enhanced properties, such as higher hardness and wear resistance in comparison to the pure nickel. The main aim of this research was to characterize the structure and corrosion properties of electrochemically produced Ni/Al2O3 nanocomposite coatings. The coatings were produced in a Watts bath modified by nickel grain growth inhibitor, cationic surfactant and the addition of alumina particles (low concentration 5 g/L. The process has been carried out with mechanical and ultrasonic agitation. The Ni/Al2O3 nanocomposite coatings were characterized by SEM, XRD and TEM techniques. In order to evaluate corrosion resistance of produced coatings, the corrosion studies have been carried out by the potentiodynamic method in a 0.5 M NaCl solution. The corrosion current, corrosion potential and corrosion rate were determined. Investigations of the morphology, topography and corrosion damages of the produced surface layers were performed by scanning microscope techniques. DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7407

  20. Crack-resistant polyimide coating for high-capacity battery anodes

    Science.gov (United States)

    Li, Yingshun; Wang, Shuo; Lee, Pui-Kit; He, Jieqing; Yu, Denis Y. W.

    2017-10-01

    Electrode cracking is a serious problem that hinders the application of many next-generation high-capacity anode materials for lithium-ion batteries. Even though nano-sizing the material can reduce fracturing of individual particles, capacity fading is still observed due to large volume change and loss of contact in the electrode during lithium insertion and extraction. In this study, we design a crack-resistant high-modulus polyimide coating with high compressive strength which can hold multiple particles together during charge and discharge to maintain contact. The effectiveness of the coating is demonstrated on tin dioxide, a high-capacity large-volume-change material that undergoes both alloy and conversion reactions. The polyimide coating improves capacity retention of SnO2 from 80% to 100% after 80 cycles at 250 mA g-1. Stable capacity of 585 mAh g-1 can be obtained even at 500 mA g-1 after 300 cycles. Scanning electron microscopy and in-situ dilatometry confirm that electrode cracking is suppressed and thickness change is reduced with the coating. In addition, the chemically-stable polyimide film can separate the surface from direct contact with electrolyte, improving coulombic efficiency to ∼100%. We expect the novel strategy of suppressing electrode degradation with a crack-resistant coating can also be used for other alloy and conversion-based anodes.

  1. Using CrAlN multilayer coatings to improve oxidation resistance of steel interconnects for solid oxide fuel cell stacks

    Science.gov (United States)

    Smith, R. J.; Tripp, C.; Knospe, A.; Ramana, C. V.; Kayani, A.; Gorokhovsky, Vladimir; Shutthanandan, V.; Gelles, D. S.

    2004-06-01

    The requirements of low-cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. The performance of steel plates with multilayer coatings, consisting of CrN for electrical conductivity and CrAlN for oxidation resistance, was investigated. The coatings were deposited using large area filtered arc deposition technology, and subsequently annealed in air for up to 25 hours at 800 °C. The composition, structure, and morphology of the coated plates were characterized using Rutherford backscattering, nuclear reaction analysis, atomic force microscopy, and transmission electron microscopy techniques. By altering the architecture of the layers within the coatings, the rate of oxidation was reduced by more than an order of magnitude. Electrical resistance was measured at room temperature.

  2. Using CrAIN Multilayer Coatings to Improve Oxidation Resistance of Steel Interconnects for Solid Oxide Fuel Cell Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Richard J.; Tripp, C.; Knospe, Anders; Ramana, C. V.; Gorokhovsky, Vladimir I.; Shutthanandan, V.; Gelles, David S.

    2004-06-01

    The requirements of low cost and high-tempurature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigatedt he performance of steel plates with multilayer coatings consisting of CrN for electrical conductivity and CrAIN for oxidation resistance. The coatings were deposited usin large area filterd arc deposition technolgy, and subsequently annealed in air for up to 25 hours at 800 degrees celsius. The composition, structer and morphology of the coated plates were characterized using RBS, nuclear reaction analysis, AFM and TEM techniques. By altering the architecture of the layers within the coatings, the rate of oxidation was reduced by more than an order of magnitute. Electrical resistance was measured at room temperature.

  3. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2006-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period we tested coated alloy coupons under conditions designed to mimic the conditions in the filter unit after the high-temperature heat recovery unit (HTHRU). The filter unit is another important area where corrosion has caused unscheduled downtime, and the remedy has been the use of sintered metal tubes made of expensive alloys such as inconel. The objective of our test was to determine if those coatings on 400-series steel that were not able to withstand the harsher conditions of the HTHRU, may be sufficiently resistant for use in the filter unit, at the reduced temperatures. Indeed, most of our coatings survived well; the exceptions were the coated porous samples of SS316. We continued making improvements to our coatings apparatus and the procedure began during the last quarter. As a result of these modifications, the coupons we are now producing are uniform. We describe the improved procedure for preparing diffusion coatings. Finally, because porous samples of steel in grades other than SS316 are not readily available, we also decided to procure SS409 powder and fabricate our own sintered porous coupons.

  4. Electrical resistivity and dielectric properties of helical microorganism cells coated with silver by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jun, E-mail: jun_cai@buaa.edu.cn [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Lan, Mingming; Zhang, Deyuan; Zhang, Wenqiang [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer We use the microorganism cells as forming templates to fabricate the bio-based conductive particles. Black-Right-Pointing-Pointer The microorganism cells selected as forming templates are Spirulina platens, which are of natural helical shape and high aspect ratio. Black-Right-Pointing-Pointer The sliver-coated Spirulina cells are a kind of lightweight conductive particles. Black-Right-Pointing-Pointer The composites containing sliver-coated Spirulina cells exhibit a lower percolation value. - Abstract: In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles by electroless silver plating process. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer. The crystal structures were characterized by employing the X-ray diffraction. The electrical resistivity and dielectric properties of samples containing different volume faction of sliver-coated Spirulina cells were measured and investigated by four-probe meter and vector network analyzer. The results showed that the Spirulina cells were successfully coated with a uniform silver coating and their initial helical shapes were perfectly kept. The electrical resistivity and dielectric properties of the samples had a strong dependence on the volume content of sliver-coated Spirulina cells and the samples could achieve a low percolation value owing to high aspect ratio and preferable helical shape of Spirulina cells. Furthermore, the conductive mechanism was analyzed with the classic percolation theory, and the values of {phi}{sub c} and t were obtained.

  5. Development of durable self-cleaning coatings using organic-inorganic hybrid sol-gel method

    Science.gov (United States)

    Kumar, Divya; Wu, Xinghua; Fu, Qitao; Ho, Jeffrey Weng Chye; Kanhere, Pushkar D.; Li, Lin; Chen, Zhong

    2015-07-01

    Self-cleaning coatings with excellent water-repellence and good mechanical properties are in high demand. However, producing such coatings with resistance to mechanical abrasion and environmental weathering remains a key challenge. Mechanically robust coatings based on tetraethylorthosilicate (TEOS) and glycidoxypropyltriethoxysilane (Glymo) have been prepared using a sol-gel method. Emphasis is given to the addition of Glymo, an epoxy silane which creates an organic matrix that blends with the inorganic Sisbnd Osbnd Si matrix formed from the TEOS. The combination of the blended matrix produced coatings with good adhesion to substrates and improved mechanical properties. Fluoroalkylsilane (FAS) and silica fillers were introduced to increase the hydrophobicity of the coating. It was found that the water contact angle (CA) of these coatings increases from 115° to 164° upon decreasing filler size from 1-5 μm to 10-20 nm. The sliding angle (SA) for coatings with 15 wt.% loading of 10-20 nm silica is around 2°. UV weathering does not show significant effect on the properties of the coatings. Mechanical properties and performances including hardness, Young's modulus, coating adhesion and abrasion resistance were systematically analyzed. In the current work, a simple self-cleaning test, which measures the extent of dirt accumulation and subsequent removal by water spray, was performed. The coatings with 15 wt.% loading of 10-20 nm silica particles show the best self-cleaning performance both before and after mechanical abrasion. The developed coating process is simple and can be easily scaled-up for large surfaces that require self-cleaning function.

  6. The Validation and Approval of Chemical Agent Resistant Coatings

    Science.gov (United States)

    2012-08-28

    resistance – Improve performance Polymeric beads Army will Discontinue use of Silica based topcoats Diatomaceous silica Talc •Integrated within...silica exposure during repair, sanding and removal operations. • Longer service life—less cost for repainting. ARL Approach and Considerations...inch stand-off distance/ 10 minutes of UVA light exposure ). Panel results show “set to handle” properties after 10 minutes following UV cure, dry

  7. Microstructure and Wear Analysis of FeBCr Based Coating Deposited by HVOF Method

    Directory of Open Access Journals (Sweden)

    M.S. Priyan

    2014-06-01

    Full Text Available Thermally sprayed coatings that are based on FeBCr-related alloy powders are widely used to improve properties such as the surface hardness and wear resistance of a variety of coated metal substrate materials. Gray cast iron is widely used in the automobile industry due to its low cost and performance. In this work Gray cast iron substrate is coated with FeBCr alloy powder to improve its performance. The microstructure and micro abrasive wear performance of both the uncoated substrates and the coated substrates were characterized by optical microscopy as well as by Scanning Electron Microscope (SEM. In addition, X-ray Diffraction (XRD was undertaken in the partial characterization of the coating. The densely layered coating had porosity levels that were below 2.5 % and a high surface hardness, of the order of 980 HV0.1. The coating exhibited excellent wear resistance when subjected to the ball-cratering test method. The low coefficients of friction of hard coating on the substrate were recorded. The wear performance of the coating was nearly 82 % better than that of the substrate, with a 0.05 N load, even under severe three body abrasive conditions.

  8. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-09-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period, we conducted several exposure tests with coated and uncoated coupons including a ''500-h'' test. The first experiment was a 316-h test and was designed to look at the performance of Ti/Ta nitride coatings, which seemed to fare the best in earlier tests. The next experiment was a 112-h test with a range of pure metals and commercially available materials. Its purpose was to help identify those metals that best withstood gasifier environment, and hence should be good ingredients for coatings. Finally, we ran a ''500-h'' test, which was also our milestone, with coupons coated with Ti/Ta nitride or Cr/Al coatings.

  9. Mussel-inspired modification of dextran for protein-resistant coatings of titanium oxide.

    Science.gov (United States)

    Park, Jae Yoon; Kim, Jee Seon; Nam, Yoon Sung

    2013-09-12

    Surface modification of inorganic materials to prevent non-specific protein adsorption is critically important for developing a biocompatible materials' platform for medical implantation, diagnostics, and therapeutics. Here we report mussel-inspired chemical modification of dextran for anti-fouling coatings of metal oxide. Catechols are conjugated to dextran via a carbamate ester linkage, producing catechol-grafted dextran with a grafting density of 7.3 mol.%. Titanium dioxide (TiO₂) is coated with the catechol-grafted dextran, and the anti-fouling effect of dextran coatings is examined by using the adsorption of human serum albumin. The mussel-inspired dextran coatings show excellent resistance to non-specific protein adsorption: the adsorption equilibrium constant (K) is 0.69 Lg(-1) for dextran-coated TiO₂ while that for pristine TiO₂ surface is 3.53 Lg(-1). This study suggests that catechol-grafted dextran is a promising material for effective anti-fouling coatings of implantable inorganic materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Failure Mechanism of a Stellite Coating on Heat-Resistant Steel

    Science.gov (United States)

    Wang, Dong; Zhao, Haixing; Wang, Huang; Li, Yuyan; Liu, Xia; He, Guo

    2017-09-01

    The Stellite 21 coating on the heat-resistant steel X12CrMoWVNbN10-1-1 (so-called COSTE) used in a steam turbine valve was found to be fatigue broken after service at around 873 K (600 °C) for about 8 years. In order to investigate the failure mechanism, a fresh Stellite 21 coating was also prepared on the same COSTE steel substrate by using the similar deposition parameters for comparison. It was found that the Stellite 21 coating was significantly diluted by the steel, resulting in a thin Fe-rich layer in the coating close to the fusion line. Such high Fe concentration together with the incessant Fe diffusion from the steel substrate to the coating during the service condition (about 873 K (600 °C) for long time) induced the eutectoid decomposition of the fcc α-Co(Fe,Cr,Mo) solid solution, forming an irregular eutectoid microstructure that was composed of the primitive cubic α'-FeCo(Cr,Mo) phase and the tetragonal σ-CrCo(Fe,Mo) phase. The brittle nature of such α'/ σ eutectoid microstructure contributed to the fatigue fracture of the Stellite 21 coating, resulting in an intergranular rupture mode.

  11. Design of barrier coatings on kink-resistant peripheral nerve conduits

    Directory of Open Access Journals (Sweden)

    Basak Acan Clements

    2016-02-01

    Full Text Available Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1 electrospinning a layer of polymer fibers onto the surface of the conduit and (2 coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery.

  12. High Density Infrared (HDI) Transient Liquid Coatings for Improved Wear and Corrosion Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ronald W. Smith

    2007-07-05

    This report documents a collaborative effort between Oak Ridge National Laboratory (ORNL), Materials Resources International and an industry team of participants to develop, evaluate and understand how high density infrared heating technology could be used to improve infiltrated carbide wear coatings and/or to densify sprayed coatings. The research included HDI fusion evaluations of infiltrated carbide suspensions such (BrazeCoat® S), composite suspensions with tool steel powders, thermally sprayed Ni-Cr- B-Si (self fluxing alloy) and nickel powder layers. The applied work developed practical HDI / transient liquid coating (TLC) procedures on test plates that demonstrated the ability to fuse carbide coatings for industrial applications such as agricultural blades, construction and mining vehicles. Fundamental studies helped create process models that led to improved process understanding and control. The coating of agricultural blades was demonstrated and showed the HDI process to have the ability to fuse industrial scale components. Sliding and brasive wear tests showed that high degree of wear resistance could be achieved with the addition of tool steel powders to carbide particulate composites.

  13. OXIDATION RESISTANCE OF NANOCRYSTAL ODS ALUMINIDE COATINGS PRODUCED BY PACK ALUMINIZING PROCESS ASSISTED BY BALL PEENING

    Institute of Scientific and Technical Information of China (English)

    Z.L. Zhan; Y.D. He; W. Gao

    2006-01-01

    Nanocrystal ODS (oxide dispersion strengthening) aluminide coatings were produced on a stainless steel and nickel-based superalloy by the pack aluminizing process assisted by ball peening. Pure Al powders and 1% of ultra-fine Y2O3 powders were mixed by ball milling. The ultra-fine Y2O3powders were dispersed in Al particles. Ball peening welded the Al particles onto the substrate and accelerated the formation of aluminide coating. Nanocrystal ODS aluminide coatings were produced by the outward growth at a much low temperature (below 600℃) in a short treatment time.The effects of the operation temperature and treatment time on the formation of the coatings were analyzed. SEM (scanning electron microscope), AFM (atomic force microscope), EDS (energy dispersive X-ray spectroscopy), XRF (X-ray fluorescence spectrometer) and XRD (X-ray diffraction )methods were applied to investigate the microstructure of the coatings. High-temperature oxidation tests were carried out to evaluate the oxidation resistance of the ODS aluminide coatings.

  14. High Density Infrared (HDI) Transient Liquid Coatings for Improved Wear and Corrosion Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ronald W. Smith

    2007-07-05

    This report documents a collaborative effort between Oak Ridge National Laboratory (ORNL), Materials Resources International and an industry team of participants to develop, evaluate and understand how high density infrared heating technology could be used to improve infiltrated carbide wear coatings and/or to densify sprayed coatings. The research included HDI fusion evaluations of infiltrated carbide suspensions such (BrazeCoat® S), composite suspensions with tool steel powders, thermally sprayed Ni-Cr- B-Si (self fluxing alloy) and nickel powder layers. The applied work developed practical HDI / transient liquid coating (TLC) procedures on test plates that demonstrated the ability to fuse carbide coatings for industrial applications such as agricultural blades, construction and mining vehicles. Fundamental studies helped create process models that led to improved process understanding and control. The coating of agricultural blades was demonstrated and showed the HDI process to have the ability to fuse industrial scale components. Sliding and brasive wear tests showed that high degree of wear resistance could be achieved with the addition of tool steel powders to carbide particulate composites.

  15. Design of barrier coatings on kink-resistant peripheral nerve conduits.

    Science.gov (United States)

    Clements, Basak Acan; Bushman, Jared; Murthy, N Sanjeeva; Ezra, Mindy; Pastore, Christopher M; Kohn, Joachim

    2016-01-01

    Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1) electrospinning a layer of polymer fibers onto the surface of the conduit and (2) coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery.

  16. The Effect of Zirconium Addition on the Oxidation Resistance of Aluminide Coatings

    Science.gov (United States)

    Zagula-Yavorska, Maryana; Pytel, Maciej; Romanowska, Jolanta; Sieniawski, Jan

    2015-04-01

    Nickel, Mar M247, and Mar M200 superalloys were coated with zirconium-doped aluminide deposited by the chemical vapor deposition method. All coatings consisted of two layers: an additive one, comprising of the β-NiAl phase and the interdiffusion one. The interdiffusion layer on pure nickel consisted of the γ'-Ni3Al phase and β-NiAl phase on superalloys. Precipitations of zirconium-rich particles were found near the coating's surface and at the interface between the additive and the interdiffusion layer. Zirconium doping of aluminide coating improved the oxidation resistance of aluminide coatings deposited both on the nickel substrate and on the Mar M200 superalloy. Precipitations of ZrO2 embedded by the Al2O3 oxide were formed during oxidation. It seems that the ZrO2 oxide increases adhesion of the Al2O3 oxide to the coating and decreases the propensity of the Al2O3 oxide rumpling and spalling.

  17. Testing of Flame Sprayed Al2O3 Matrix Coatings Containing TiO2

    Directory of Open Access Journals (Sweden)

    Czupryński A.

    2016-09-01

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

  18. The study of crack resistance of TiAlN coatings under mechanical loading and thermal cycle testing

    Energy Technology Data Exchange (ETDEWEB)

    Akulinkin, Alexandr, E-mail: aaa@ispms.tsc.ru; Shugurov, Artur, E-mail: shugurov@ispms.tsc.ru; Sergeev, Viktor, E-mail: retc@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Panin, Alexey, E-mail: pav@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Cheng, C.-H. [National Cheng Kung University, Tainan, Taiwan (China)

    2015-10-27

    The effect of preliminary ion bombardment of 321 stainless steel substrate on crack resistance of TiAlN coatings at uniaxial tension and thermal cycling is studied. The ion-beam treatment of the substrate is shown to substantially improve the adhesion strength of the coatings that prevents their delamination and spalling under uniaxial tension. The resistance to crack propagation and spalling by the thermal shock is higher in the TiAlN coating deposited onto the substrate subjected to Ti ion bombardment as compared to that in the TiAlN coating deposited onto the initial substrate.

  19. Nanocomposite TiSiBC Hard Coatings with High Resistance to Wear, Fracture and Scratching

    Science.gov (United States)

    Mahato, P.; Nyati, G.; Singh, R. J.; Mishra, S. K.

    2016-09-01

    The sliding wear under fretting condition, scratch adhesion, deformation behavior during micro- and nanoscratch studies have been studied for nanocomposite TiSiBC hard coating deposited on steel substrate by magnetron sputtering. The nanocomposite coatings having hardness and modulus around 30 and 300 GPa, respectively, showed a very significant decrease in fretting wear as compared to the uncoated steel. Pileup occurred along the sides of the scratch track due to plastic deformation of the substrate at the scratch load; however, cracks were not seen in films. The coefficient of friction remained scratch, higher wear resistance, higher toughness and low coefficient of friction.

  20. Oxidation resistance of co-deposited Ni-SiC nanocomposite coating

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ni-6.0%SiC (mass fraction) nanocomposite coating was prepared from a nickel sulfate bath by co-electrodeposition of Ni and SiC nanoparticles in an average size of 30 nm. The oxidation at 1 000 ℃ shows that the Ni-6.0%SiC nanocomposite coating has a superior oxidation resistance compared with the pure Ni film due to the formation of SiO2 oxide particles along grain boundaries,blocking the outward diffusion of Ni and changing the oxidation growth mechanism. The effect of SiC nanoparticles on the oxidation progress was discussed in detail.

  1. Protection of 2024-T3 aluminium alloy by corrosion resistant phytic acid conversion coating

    Science.gov (United States)

    Shi, Hongwei; Han, En-Hou; Liu, Fuchun; Kallip, Silvar

    2013-09-01

    The corrosion protection properties of environmentally friendly phytic acid conversion coatings were studied on 2024-T3 aluminium alloy. The films were prepared under acidic conditions with various pH values and characterised by SEM, EDS, ATR-FTIR and electrochemical techniques. The results indicate that the conversion coatings obtained by immersing the alloy in phytic acid solutions at pH from 3 to 5.5 provide excellent corrosion resistance. ATR-FTIR confirms that the film is formed by deposition of reaction products between Al3+ and phosphate groups in phytic acid molecules. The conformation models of the deposition film are proposed.

  2. Pressure vessel with impact and fire resistant coating and method of making same

    Science.gov (United States)

    DeLay, Thomas K. (Inventor)

    2005-01-01

    An impact and fire resistant coating laminate is provided which serves as an outer protective coating for a pressure vessel such as a composite overwrapped vessel with a metal lining. The laminate comprises a plurality of fibers (e.g., jute twine or other, stronger fibers) which are wound around the pressure vessel and an epoxy matrix resin for the fibers. The epoxy matrix resin including a plurality of microspheres containing a temperature responsive phase change material which changes phase in response to exposure thereof to a predetermined temperature increase so as to afford increased insulation and heat absorption.

  3. Three body abrasion of laser surface alloyed aluminium AA1200

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-06-01

    Full Text Available on the composition of the alloying powder mixture. The wear performance of the alloyed surfaces was characterised using an ASTM G65 three body dry abrasion apparatus. A maximum 82% improvement in the wear resistance of the pure aluminium was achieved with a 40 wt% Ni...

  4. Selected Properties Of Thermally Sprayed Oxide Ceramic Coatings

    Directory of Open Access Journals (Sweden)

    Czupryński A.

    2015-09-01

    Full Text Available The article presents the results of the study on exploitation properties of flame sprayed ceramic coatings produced by oxide ceramic material in the form of powder on the aluminum oxide Al2O3 matrix with 3% titanium oxide TiO2 addition and also on the zirconium oxide (ZrO2 matrix with 30% calcium oxide (CaO on the substrate of unalloyed structural steel of S235JR grade. As a primer powder, metallic powder on the base of Ni-Al-Mo has been applied. Plates with dimensions of 5×200×300 mm and also front surfaces of ∅40×50 mm cylinders have been flame sprayed. Spraying of primer coating has been done using RotoTec 80 torch and external specific coating has been done with CastoDyn DS 8000 torch. Investigations of coating properties are based on metallography tests, phase composition research, measurement of microhardness, coating adhesion to the ground research (acc. to EN 582:1996 standard, abrasive wear resistance (acc. to ASTM G65 standard and erosion wear resistance (acc. to ASTM G76-95 standard and thermal stroke study. Performed tests have shown that the flame spraying with 97%Al2O3 powder containing 3% TiO2 and also by the powder based on zirconium oxide (ZrO2 containing 30% calcium oxide (CaO performed in a wide range of technological parameters allow to obtain high quality ceramic coatings with thickness up to ca. 500 μm on a steel substrate. The primer coating sprayed with the Ni-Al-Mo powder to the steel substrate and external coatings sprayed has the of mechanical bonding character. The coatings are characterized by high adhesion to the substrate and also high erosion and abrasive wear resistance and the resistance for cyclic thermal stroke.

  5. Influence of solid contaminants in oil on wear characteristics of nano-Al2O3/Ni composite coating

    Institute of Scientific and Technical Information of China (English)

    杜令忠; 徐滨士; 董世运; 杨华; 吴毅雄

    2004-01-01

    Solid contaminants in lubrication system will cause severe wear of sliding components. In order to improve the wear resistance of the material in oil containing solid contaminants, the brush plated nano-A12 O3/Ni composite coating was prepared and the influence of the sand content and sand size on the tribological property of the coating in oil containing solid contaminants was tested with ball-on-disc tester. The results show that the wear volume increases with increasing the sand content and sand size, and the wear resistance of the composite coating is 20% higher than that of the high-speed plain nickel coating. The main wear mechanisms of the coatings are abrasive wear and adhesive wear. And due to the nano-particle strengthening effect, the wear resistance of the composite coating is improved.

  6. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Jordi Perez; Marc Hornbostel; Kai-Hung Lau; Angel Sanjurjo

    2007-05-31

    Advanced electric power generation systems use a coal gasifier to convert coal to a gas rich in fuels such as H{sub 2} and CO. The gas stream contains impurities such as H{sub 2}S and HCl, which attack metal components of the coal gas train, causing plant downtime and increasing the cost of power generation. Corrosion-resistant coatings would improve plant availability and decrease maintenance costs, thus allowing the environmentally superior integrated-gasification-combined-cycle (IGCC) plants to be more competitive with standard power-generation technologies. Heat-exchangers, particle filters, turbines, and other components in the IGCC system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy will improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. In this study, the use of corrosion-resistant coatings on low alloy steels was investigated for use as high-temperature components in IGCC systems. The coatings were deposited using SRI's fluidized-bed reactor chemical vapor deposition technique. Diffusion coatings of Cr and Al were deposited by this method on to dense and porous, low alloy stainless steel substrates. Bench-scale exposure tests at 900 C with a simulated coal gas stream containing 1.7% H{sub 2}S showed that the low alloy steels such SS405 and SS409 coated with

  7. The Tribological Performance of Hardfaced/ Thermal Sprayed Coatings for Increasing the Wear Resistance of Ventilation Mill Working Parts

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2015-09-01

    Full Text Available During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings. The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC.

  8. Investigation on Interface Structure and Wear-resistant Properties of HVOF Sprayed Carbides Coating onto Copper Substrate

    Institute of Scientific and Technical Information of China (English)

    HOU Li-feng; ZHANG Heng-jin; WEI Ying-hui; YAN Kai; HU Lan-qing; XU Bing-she

    2004-01-01

    In this paper, we deposited carbides on copper substrate by High velocity oxy-fuel (HVOF) spraying. The structure of the coating and microstructure of the substrate-coating interface have been investigated by means of scanning electron microscope (SEM) and transmission electron microscopy (TEM). We observed the worn surface of the coating and investigated the wear mechanism. The results show that the microstructure of the interface between HVOF sprayed coating and substrate which consists of the amorphous layers, nanocrystalls in the coating and dislocation cells in copper substrate,etc. is complex. The amorphous layers are formed from heated adhesion after rapidly cooling, while the nanocrystalls come from the fragmentation of half-molten carbides. At the same time we found that the wear-resistant properties of the WC-Co coating is better than that of Cr3C2-NiCr coating at room temperature. The early wear-resistance of the HVOF sprayed coating is poor because of the roughness of its surface or bad bond of hard composite particles. The high velocity of molten droplets is propitious to fill up the interspaces between carbides, so as to make the coating more compact and reduce its porosities, thus the wear-resistance of carbides coatings is improved.

  9. Investigation on Interface Structure and Wear-resistant Properties of HVOF Sprayed Carbides Coating onto Copper Substrate

    Institute of Scientific and Technical Information of China (English)

    HOULi-feng; ZHANGHeng-jin; WEIYing-hui; YANKai; HULan-qing; XUBing-she

    2004-01-01

    In this paper, we deposited carbides on copper substrate by High velocity oxy-fuel (HVOF) spraying. The structure of the coating and microstructure of the substrate-coating interface have been investigated by means of scanning electron microscope (SEM) and transmission electron microscopy (TEM). We observed the worn surface of the coating and investigated the wear mechanism. The results show that the microstructure of the interface between HVOF sprayed coating and substrate which consists of the amorphous layers, nanocrystalls in the coating and dislocation cells in copper substrate, etc. is complex. The amorphous layers are formed from heated adhesion after rapidly cooling, while the nanocrystalls come from the fragmentation of half-molten carbides. At the same time we found that the wear-resistant properties of the WC-Co coating is better than that of Cr3C2-NiCr coating at room temperature. The early wear-resistance of the HVOF sprayed coating is poor because of the roughness of its surface or bad bond of hard composite particles. The high velocity of molten droplets is propitious to fill up the interspaces between carbides, so as to make the coating more compact and reduce its porosities, thus the wear-resistance of carbides coatings is improved.

  10. 小湾水电站泄洪洞抗冲耐磨混凝土施工综述%Construction of Abrasion-resistant Concrete for the spillway Tunnel of Xiaowan Hydropower Station

    Institute of Scientific and Technical Information of China (English)

    李众; 罗毅; 李然; 字林

    2011-01-01

    As the high head, high velocity and large flow of flood discharge, the concrete of spillway tunnel in Xiaowan Hydropower Station is easy to be damaged by cavitation. By reasonable pouring, mix proportion optimizing, effective temperature control and reasonable curing, the concrete quality of spillway tunnel is guaranteed and no crack found. The successful concrete construction and quality control provides guarantees on reducing surface cavitation and increasing abrasion-resistance capacity.%小湾水电站泄洪洞在泄洪时具有高水头、高流速、泄量大的特点,对混凝土冲刷力强,容易产生空蚀破坏.通过合理选择浇筑措施、优选配合比、有效的温度控制以及合理的养护,目前,泄洪洞各方面质量均满足要求,且未发现裂缝.泄洪洞抗冲耐磨混凝土施工及质量控制的成功,为减小泄洪洞过流面空蚀和抗冲耐磨提供了保障.

  11. Development of durable self-cleaning coatings using organic–inorganic hybrid sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Divya [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Wu, Xinghua [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore); Fu, Qitao [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Ho, Jeffrey Weng Chye [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore); Kanhere, Pushkar D. [Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore); Li, Lin [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Chen, Zhong, E-mail: ASZChen@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute at NTU - ERI@N, 1 CleanTech Loop, #06-04, CleanTech One, Singapore 637141 (Singapore)

    2015-07-30

    Highlights: • A facile method to produce sol–gel based self-cleaning coatings is described. • Effect of filler size and content is evaluated via contact angle, sliding angle, and surface morphology. • Coating with 15 wt.% nano-sized silica fillers exhibits the best self-cleaning performance. • The coatings are resistant to UV radiation and retain the functionality after the abrasion test. • A self-cleaning test and scheme to quantify the self-cleaning efficiency are described in this work. - Abstract: Self-cleaning coatings with excellent water-repellence and good mechanical properties are in high demand. However, producing such coatings with resistance to mechanical abrasion and environmental weathering remains a key challenge. Mechanically robust coatings based on tetraethylorthosilicate (TEOS) and glycidoxypropyltriethoxysilane (Glymo) have been prepared using a sol–gel method. Emphasis is given to the addition of Glymo, an epoxy silane which creates an organic matrix that blends with the inorganic Si−O−Si matrix formed from the TEOS. The combination of the blended matrix produced coatings with good adhesion to substrates and improved mechanical properties. Fluoroalkylsilane (FAS) and silica fillers were introduced to increase the hydrophobicity of the coating. It was found that the water contact angle (CA) of these coatings increases from 115° to 164° upon decreasing filler size from 1–5 μm to 10–20 nm. The sliding angle (SA) for coatings with 15 wt.% loading of 10–20 nm silica is around 2°. UV weathering does not show significant effect on the properties of the coatings. Mechanical properties and performances including hardness, Young's modulus, coating adhesion and abrasion resistance were systematically analyzed. In the current work, a simple self-cleaning test, which measures the extent of dirt accumulation and subsequent removal by water spray, was performed. The coatings with 15 wt.% loading of 10–20 nm silica particles

  12. Influence of the layer architecture of DLC coatings on their wear and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Bobzin, Kirsten; Bagcivan, Nazlim; Theiss, Sebastian; Weiss, Raphael [RWTH Aachen (Germany). Inst. fuer Oberflaechentechnik; Depner, Udo; Trossmann, Torsten; Ellermeier, Joerg; Oechsner, Matthias [Technische Univ. Darmstadt (Germany). Inst. fuer Werkstoffkunde

    2012-06-15

    In this work, the influence of diamond-like carbon top layers deposited on two different types of layer architecture on wear and corrosion resistance is investigated. Physical vapour deposition coatings with a-C:H top layer of various thicknesses were deposited on plasma nitrided 42CrMo4 by reactive magnetron sputter ion plating. Beneath the top layer, an architecture with and without a-C interlayers was deposited. Investigations using potentiodynamic polarisation testing in artificial seawater as well as an impact tribometer show that it is possible to protect low-alloy heat treatable steel from both corrosion and wear by using pretreatment and an appropriate diamond-like carbon coating. Thicker a-C:H top layers as well as the addition of a-C interlayers resulted in an overall improvement in the coating behaviour. (orig.)

  13. A Magnetic Properties and Corrosion Resistance of Fe-Si Alloy Coating Prepared on Mild Steel

    Directory of Open Access Journals (Sweden)

    Yi WANG

    2014-12-01

    Full Text Available The present work deals with preparation of Fe3Si coatings on mild steel and evaluation of its magnetic property and corrosion behavior. Magnetic property of coatings was measured using a vibrating sample magnetometer, the result shows that the saturation magnetization reached to the maximum value (214.1 emu•g-1 and the coercivity fell to the lowest (23.11 Oe in 1000oC. Corrosion behaviour of the coatings was studied using polarization in 3.5%NaCl solution. It was found that the corrosion current density (icorr decreased with increasing of heat treatment temperature up to 1000oC, indicating an improvement in corrosion resistance. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6446

  14. High temperature oxidation resistance of magnetron-sputtered homogeneous CrAlON coatings on 430 steel

    Science.gov (United States)

    Garratt, E.; Wickey, K. J.; Nandasiri, M. I.; Moore, A.; AlFaify, S.; Gao, X.; Kayani, A.; Smith, R. J.; Buchanan, T. L.; Priyantha, W.; Kopczyk, M.; Gannon, P. E.

    2009-11-01

    The requirements of low cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of steel plates with homogenous coatings of CrAlON (oxynitrides). The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas. Oxygen in these coatings was not intentionally added. Oxygen might have come through contaminated nitrogen gas bottle, leak in the chamber or from the partial pressure of water vapors. Nitrogen was added during the growth process to get oxynitride coating. The Cr/Al composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800 oC. The composition of the coated plates and the rate of oxidation were characterized using Rutherford backscattering (RBS) and nuclear reaction analysis (NRA). Surface characterization was carried out using Atomic Force Microscopy (AFM) and surfaces of the coatings were found smooth on submicron scale. From our results, we conclude that Al rich coatings are more susceptible to oxidation than Cr rich coatings.

  15. Corrosion Resistance of the Superhydrophobic Mg(OH2/Mg-Al Layered Double Hydroxide Coatings on Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Fen Zhang

    2016-04-01

    Full Text Available Coatings of the Mg(OH2/Mg-Al layered double hydroxide (LDH composite were formed by a combined co-precipitation method and hydrothermal process on the AZ31 alloy substrate in alkaline condition. Subsequently, a superhydrophobic surface was successfully constructed to modify the composite coatings on the AZ31 alloy substrate using stearic acid. The characteristics of the composite coatings were investigated by means of X-ray diffractometer (XRD, Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, scanning electronic microscope (SEM and contact angle (CA. The corrosion resistance of the coatings was assessed by potentiodynamic polarization, the electrochemical impedance spectrum (EIS, the test of hydrogen evolution and the immersion test. The results showed that the superhydrophobic coatings considerably improved the corrosion resistant performance of the LDH coatings on the AZ31 alloy substrate.

  16. Resistance of Nanostructured Environmental Barrier Coatings to the Movement of Molten Salts

    Science.gov (United States)

    Rao, S.; Frederick, L.; McDonald, A.

    2012-09-01

    Corrosion of components in a recovery boiler is a major problem faced by the pulp and paper industry. The superheater tubes become severely corroded due to the presence of sulfidic gases in the boiler and molten salts which are deposited on the surface of the tubes. As a result, the boiler must be decommissioned for expensive maintenance and repairs. Yttria-stabilized zirconia (YSZ) coatings have been shown to provide corrosion resistance when applied on gas turbines operating at high temperatures. Air plasma-sprayed YSZ environmental barrier coatings on Type 309 stainless steel were exposed to three different corrosive environments: Test A—600 °C, salt vapors, flue gases, 168 h; Test B—600 °C, molten salt, air, 168 h; and Test C—600 °C, molten salt, flue gases, 168 h. Two different types of YSZ coatings—conventional YSZ and nanostructured YSZ—were tested to study their resistance to corrosion and molten salt penetration. The performances of both types of coatings were evaluated, and a comparative study was conducted. It was found that the nanostructured YSZ samples protected the stainless steel substrate better than their conventional counterparts. This superior performance was attributed to the presence of semi-molten nano-agglomerates present in the coating microstructure, which acted as collection points for the penetrating molten salts.

  17. Corrosion resistance of biodegradable polymeric layer-by-layer coatings on magnesium alloy AZ31

    Science.gov (United States)

    Cui, Lan-Yue; Zeng, Rong-Chang; Zhu, Xiao-Xiao; Pang, Ting-Ting; Li, Shuo-Qi; Zhang, Fen

    2016-06-01

    Biocompatible polyelectrolyte multilayers (PEMs) and polysiloxane hybrid coatings were prepared to improve the corrosion resistance of biodegradable Mg alloy AZ31. The PEMs, which contained alternating poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH), were first self-assembled on the surface of the AZ31 alloy substrate via electrostatic interactions, designated as (PAH/PSS)5/AZ31. Then, the (PAH/PSS)5/AZ31 samples were dipped into a methyltrimethoxysilane (MTMS) solution to fabricate the PMTMS films, designated as PMTMS/(PAH/PSS)5/AZ31. The surface morphologies, microstructures and chemical compositions of the films were investigated by FE-SEM, FTIR, XRD and XPS. Potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution measurements demonstrated that the PMTMS/(PAH/PSS)5/AZ31 composite film significantly enhanced the corrosion resistance of the AZ31 alloy in Hank's balanced salt solution (HBSS). The PAH and PSS films effectively improved the deposition of Ca-P compounds including Ca3(PO4)2 and hydroxyapatite (HA). Moreover, the corrosion mechanism of the composite coating was discussed. These coatings could be an alternative candidate coating for biodegradable Mg alloys.

  18. The enhanced corrosion resistance of UMAO coatings on Mg by silane treatment

    Institute of Scientific and Technical Information of China (English)

    Muqin Li; Jiang Liu; Jungang Li; Yongjiang Li; Shouduo Lu; Yuqi Yuan

    2014-01-01

    The surface silanization was carried out on ultrasonic micro-arc oxidation (UMAO) coatings on pure magnesium using KH550 as silane coupling agent (SCA). The surface morphology, chemical bonds and corrosion resistance of the silane films were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and electrochemical workstation, respectively. The results showed that hybrid coatings were successfully prepared on pure magnesium by UMAO-NaOH (1 mol/L, 2 mol/L, 3 mol/L)-SCA processing. The organic films with Si–O–Mg bonds are helpful for the reduction of the pores in UMAO coatings. The pores decreased with increasing NaOH concentration. Compared with single UMAO treatment, the corrosion potentials (Ecorr) of magnesium plates with UMAO-NaOH (1 mol/L, 2 mol/L, 3 mol/L)-SCA treatment increased by 29 mV, 53 mV and 75 mV, respectively, meanwhile the corrosion current density (Icorr) reduced one to two orders of magnitude. It indicated that the corrosion resistance of the coatings was improved by silane treatment.

  19. The enhanced corrosion resistance of UMAO coatings on Mg by silane treatment

    Directory of Open Access Journals (Sweden)

    Muqin Li

    2014-10-01

    Full Text Available The surface silanization was carried out on ultrasonic micro-arc oxidation (UMAO coatings on pure magnesium using KH550 as silane coupling agent (SCA. The surface morphology, chemical bonds and corrosion resistance of the silane films were investigated by scanning electron microscope (SEM, Fourier transform infrared spectroscopy (FTIR and electrochemical workstation, respectively. The results showed that hybrid coatings were successfully prepared on pure magnesium by UMAO-NaOH (1 mol/L, 2 mol/L, 3 mol/L-SCA processing. The organic films with Si–O–Mg bonds are helpful for the reduction of the pores in UMAO coatings. The pores decreased with increasing NaOH concentration. Compared with single UMAO treatment, the corrosion potentials (Ecorr of magnesium plates with UMAO-NaOH (1 mol/L, 2 mol/L, 3 mol/L-SCA treatment increased by 29 mV, 53 mV and 75 mV, respectively, meanwhile the corrosion current density (Icorr reduced one to two orders of magnitude. It indicated that the corrosion resistance of the coatings was improved by silane treatment.

  20. Microstructure and Wear Resistance of Laser Clad Cobalt-Based Alloy/SiCp Composite Coating

    Institute of Scientific and Technical Information of China (English)

    LI Ming-xi; SI Song-hua; HE Yi-zhu; SUN Guo-xiong

    2004-01-01

    The SiC