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Characterization of ZrO_(2) ceramic coatings on ZrH1.8 prepared in different electrolytes by micro-arc oxidation

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Rare Metals 2022年第3期41卷 1043-1050页

作者： Zhi-Gang Wang Wei-Dong Chen Shu-Fang Yan Xiu-Juan Fan Zhi-Gao Xu College of Materials and Engineering Inner Mongolia University of TechnologyHohhot 010051China Division of Mineral Resources Metallurgy and MaterialsGeneral Research Institute for Nonferrous MetalsBeijing 100088China Key Laboratory for Green Chemical Process of Ministry of Education Wuhan Institute of TechnologyWuhan 430073China

ZrO_(2)ceramic coatings were directly prepared on the surface of ZrH_(1.8) in silicate and phosphate elec-trolytes by micro-arc oxidation(MAO)technique,respec-tively.The microstructure,chemical composition and phase composition of ZrO_(2)ceramic coatings were inves-tigated by X-ray diffraction(XRD),energy-dispersive spectrometry(EDS)and scanning electron microscopy(SEM).The anti-permeation effect was measured by means of vacuum dehydrogenation experiment.It is found that the coating fabricated in phosphate electrolyte is more compact than that in silicate electrolyte.The coatings fabricated on the surface of ZrH_(1.8) are composed of M-ZrO_(2),T-ZrO_(2) and C-ZrO_(2).EDS analysis indicates that the coatings are mainly composed of O and Zr.Vacuum dehydrogenation experiment shows that the permeation reduction factor(PRF)of coating prepared in phosphate electrolyte is su-perior to that in the silicate electrolyte,and the PRF value reaches up to 11.2,which can enhance the resistance effect of hydrogen significantly.

关键词： ZrO_(2)ceramic coating Zirconium hydride micro-arc oxidation Hydrogen permeation barrier

Corrosion resistance and mechanisms of smart micro-arc oxidation/epoxy resin coatings on AZ31 Mg alloy: Strategic positioning of nanocontainers

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Journal of Magnesium and Alloys 2023年第12期11卷 4562-4574页

作者： Ai-meng Zhang Chengbao Liu Pu-sheng Sui Cong Sun Lan-yue Cui M.Bobby Kannan Rong-Chang Zeng College of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450002China School of Engineering University of NewcastleCallaghanNew South Wales 2308Australia

Smart micro-arc oxidation(MAO)/epoxy resin(EP) composite coatings were formed on AZ31 magnesium(Mg) alloy. Mesoporous silica nanocontainers(MSN) encapsulated with sodium benzoate(SB) corrosion inhibitors were strategically incorporated in the MAO micropores and in the top EP layer. The influence of the strategic positioning of the nanocontainers on the corrosion protective performance of coating was investigated. The experimental results and analysis indicated that the superior corrosion resistance of the hybrid coating is ascribed to the protection mechanisms of the nanocontainers. This involves two phenomena:(1) the presence of the nanocontainers in the MAO micropores decreased the distance between MSN@SB and the substrate, demonstrating a low admittance value(^5.18 × 10^(-8)Ω^(-1)), and thus exhibiting significant corrosion inhibition and self-healing function;and(2) the addition of nanocontainers in the top EP layer densified the coating via sealing of the inherent defects, and hence the coating maintained higher resistance even after 90 days of immersion(1.13 × 10^(10)Ω cm^(2)).However, the possibility of corrosion inhibitors located away from the substrate transport to the substrate is reduced, reducing its effective utilization rate. This work demonstrates the importance of the positioning of nanocontainers in the coating for enhanced corrosion resistance,and thereby providing a novel perspective for the design of smart protective coatings through regulating the distribution of nanocontainers in the coatings.

关键词： Nanocontainers Self-healing coating micro-arc oxidation Corrosion protection Magnesium alloys

Development of metal-organic framework(MOF) decorated graphene oxide/Mg Al-layered double hydroxide coating via microstructural optimization for anti-corrosion micro-arc oxidation coatings of magnesium alloy

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Journal of Materials Science & Technology 2022年第35期130卷 12-26页

作者： Yanning Chen Liang Wu Wenhui Yao Jiahao Wu Jianpeng Xiang Xiaowei Dai Tao Wu Yuan Yuan Jingfeng Wang Bin Jiang Fusheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400044China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

An efcient and simple in-situ growth strategy has been discovered for the preparation of highly reproducible and continuous symbiotic ZIF-8-based anticorrosion coating by using graphene oxide(GO)/Mg AlNO3layered double hydroxides(G/LDHs) buffer layer as a new type of connecting carrier based on micro-arc oxide(MAO) coating of AZ31 magnesium alloy. The components of ZIF-8 were adsorbed and bounded to the surface of the G/LDHs buffer layer-modified substrates to promote the nucleation of ZIF-8,thus growing a phase-pure, uniform, and good symbiosis ZIF-8 membrane. ZIF-8 particles with different growth times compensate for the grain boundary defects of the G/LDHs coating precursor buffer layer to different degrees. The prepared ZIF-8-based coating has excellent stability and corrosion resistance. The results demonstrate that the G/LDHs buffer layer provides a new channel for the MOF-modified MAO substrate of AZ31 magnesium alloy. It also proves that it is feasible to build high-performance anticorrosive coatings with MOF materials.

关键词： Zeolitic-imidazole framework Layered double hydroxide Graphene oxide micro-arc oxidation Corrosion protection Magnesium alloy

Titania coating formation on hydrostatically extruded pure titanium by micro-arc oxidation method

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Journal of Materials Science & Technology 2022年第16期111卷 224-235页

作者： Ł.Maj D.Wojtas A.Jarz˛ebska M.Bieda K.Trembecka-Wójciga R.Chulist W.Kozioł A.Góral A.Trelka K.Janus J.Kawałko M.Kulczyk F.Muhaffel H.Çimeno˘glu K.Sztwiertnia Institute of Metallurgy and Materials Science Polish Academy of SciencesReymonta 25Krakow 30-059Poland Faculty of Physics and Applied Computer Science AGH University of Science and TechnologyKrakowPoland Academic Centre of Materials and Nanotechnology AGH University of Science and TechnologyKrakowPoland Institute of High Pressure Physics Polish Academy of SciencesWarsawPoland Department of Metallurgical and Materials Engineering Istanbul Technical UniversityIstanbulTurkey

In this work,the microstructure of titania coating fabricated on the surface of hydrostatically extruded titanium grade 4 with the use of the micro-arc oxidation method was studied.The surface topography and microstructure investigations performed with atomic force microscopy and scanning and transmission electron microscopy revealed that,by using an Na_(2)HPO_(4)electrolyte,a well-adherent porous coating is produced on the top surface and side walls of the extruded rod.The distribution of chemical elements was analyzed by using energy dispersive X-ray spectroscopy.The chemical elements dissolved in the electrolyte(Na,P and O)incorporated into the coating.Sodium locates preferentially in the outer part of the coating,while phosphorus and oxygen are distributed throughout the whole coating.The most relevant finding shows that a grain refinement caused by a hydrostatic extrusion provoked an increase in density of high-angle grain boundaries(HAGB),which in turn secured the formation of a continuous amorphous layer close to the substrate.The presence of this layer compensates for the effect of anisotropic substrate,producing a comparable and homogenous microstructure with a large number of micropores.

关键词： micro-arc oxidation Titanium of commercial purity Hydrostatic extrusion Surface topography microstructure

micro-arc oxidation of magnesium alloys:A review

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Journal of Materials Science & Technology 2022年第23期118卷 167-189页

作者： Wenhui Yao Liang Wu Jingfeng Wang Bin Jiang Dingfei Zhang Maria Serdechnova Tatsiana Shulha Carsten Blawert Mikhail L.Zheludkevich Fusheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400044China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Institute of Surface Science Helmholtz-Zentrum HereonMax-Planck Str.1Geesthacht 21502Germany Institute of Materials Science Faculty of EngineeringCAU Kiel UniversityKaiser Str.2Kiel 24143Germany

Magnesium(Mg)and its alloys present great potential to be extensively applied in different applications.However,the relatively poor resistance to corrosion and wear significantly restricts their applications in practice.As one of strategies of surface treatment,micro-arc oxidation(MAO)process attracts a lot of attention,since it does not use neither expensive equipment,nor complicated manipulation.This review systematically discusses MAO mechanism and some typical models,which still need to be further developed to provide a better understanding and guide for future researchers.Subsequently,main influencing factors of MAO process are analyzed in detail.Further,some popular applications of MAO coatings are respectively reviewed,including biomedical application,decoration,thermal control,corrosion and wear resistance,and industrial applications in practice.The existing issues and future perspectives are finally discussed to further accelerate extensive applications of Mg alloys.

关键词： micro-arc oxidation Magnesium alloys Review Main MAO applications Existing issues and future perspective

High-temperature oxidation resistance of ceramic coatings on titanium alloy by micro-arc oxidation in aluminate solution

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Progress in Natural Science:Materials International 2022年第4期32卷 401-406页

作者： Guodong Hao Daiyue Zhang Liyan Lou Longcheng Yin Mudanjiang Normal University Harbin Institute of Technology

Ceramic coatings with aluminum titanuate(Al2TiO5) were prepared on Ti–6Al–4V alloy using pulsed bi-polar micro-arc oxidation(MAO). The micromorphology and phase composition of the micro-arc-oxidition ceramic coatings on the titanium alloy were characterized by X-ray powder diffraction(XRD), and scanning electron microscopy(SEM) respectively. The results revealed that the distinct discharge channels and pores on the surface of the micro-arc-oxidition coatings appeared, and these channels were connected in the molten state. The electrolyte concentration was inversely proportional to the coating hardness; additionally, the coating prepared with sodium aluminate and sodium hypophosphite concentrations of 4 g/L and 0.5 g/L, respectively, was the most refined after high-temperature sintering, and it was demonstrated to better prevent oxidation. Increasing the electrolyte concentration coincided with fluctuating coating thermal shock resistance. The thermal shock resistance of the coating respectively prepared with sodium aluminate, and the sodium hypophosphite concentrations of 4 g/L and 0.5 g/L was the highest. Additionally, the high-concentration coatings performed significantly better than the low-concentration coatings. The oxidation resistance of the coating samples was also significantly higher than that of the TC4 titanium alloy substrate. The adhesion strength between the coatings and the substrate with and without the sealing treatment was measured by tensile tests. Then, the high-temperature oxidation performance of the coating samples with and without the sealing treatment was investigated by conducting a hightemperature oxidation experiment at a calcinating temperature of 500°C. The results indicate that the adhesion strength between the coatings and substrate was high for the as-prepared and sealed micro-arc oxidation samples regardless of whether they were calcined. The high-temperature oxidation mass increase curves for the sealed and unsealed coating samples calcined at 500°C for 500 h revealed that the

关键词： micro-arc oxidation Titanium alloy Aluminate High-temperature oxidation Electrolyte concentration

A comparative study of surface characterization and corrosion behavior of micro-arc oxidation treated Ti-6Al-4V alloy prepared by SEBM and SLM

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Journal of Iron and Steel Research(International) 2023年第1期30卷 165-175页

作者： Qing-bo Yan Tong Xue Shi-feng Liu Wan-lin Wang Yan Wang Xi Song Xin Yang Wei-wei Shang Xi’an University of architecture and Technology Xi’an 710055ShaanxiChina School of Metallurgical and Engineering Xi’an University of Architecture and TechnologyXi’an 710055ShaanxiChina School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048ShaanxiChina Shaanxi Steel Group Industrial Innovation Research Institute Co. Ltd.Hanzhong 723000ShaanxiChina

Additively manufactured Ti-6Al-4V(TC4)parts have been successfully employed as artificial implants in dental and orthopedic surgery due to their excellent mechanical properties.However,the suboptimal corrosion resistance limits their applications.The surface characterization and corrosion behavior of micro-arc oxidation(MAO)treated TC4 alloy prepared by selective electron beam melting(SEBM)and selective laser melting(SLM)technologies were compared.The corrosion resistance mechanism of SLM-MAO and SEBM-MAO was clarified through the analysis of the microstructure evolution,surface morphology,and electrochemical experiments.The results show that the anatase-type TiO_(2) is partially transformed into the slankite phase after MAO treatment.The surface roughness of SEBM sample was reduced by MAO coating,while the surface roughness of SLM sample increased after MAO,which is related to the difference between the microstructure of the deposited samples caused by different additive manufacturing technologies.When MAO time was 15 min,SLM-MAO and SEBM-MAO coating displayed the best and the worst corrosion resistance,respectively.

关键词： TC4 alloy Selective laser melting Selective electron beam melting micro-arc oxidation Corrosion resistance

Effect of K2TiO(C2O4)2 Addition in Electrolyte on the microstructure and Tribological Behavior of micro-arc oxidation Coatings on Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第11期30卷 1109-1118页

作者： Jian-Li Wang Wei Yang Da-Peng Xu Xiao-Fei Yao School of Materials Science and Chemical Engineering Xi'an Technological University Xi'an 710021 China

micro-arc oxidation （MAO） coatings with different concentrations of K2TiO（C2O4）2 in the sodium silicate base electrolyte were prepared on 6061 aluminum alloy with the aim of promoting a better understanding of the formation mechanisms and tribological behaviors of the coatings. Scanning electron microscopy （SEM） assisted with energy-dis- persive X-ray spectroscopy （EDS）, X-ray photoelectron spectroscopy （XPS） and friction test were employed to charac- terize the MAO processes and microstructure of the resultant coatings. Results showed that the composition and microstructure of the coatings were significantly affected by the addition of KETiO（CaO4）2. A sealing microstructure of MAO coating was obtained with the addition of K2TiO（C2O4）2. Ti element from K2TiO（C2O4）2 was only absorbed into the defects of micropores under surface energy in the early stage, while in the later stage, Ti element was predominant in the micropores and distributed on the coatings under plasma discharge to form TiO2. It was demonstrated that Ti and Si elements from the electrolyte could interact with each other during the MAO process and the interaction mechanism was systematically analyzed. Wear resistance of the MAO coatings with K2TiO（C2O4）2 addition was significantly improved compared with that of the MAO coatings without K2TiO（C2O4）2 addition.

关键词： Aluminum alloy micro-arc oxidation K2TiO（C2O4）2 Coating formation mechanism Tribological behavior

Characterization of ceramic coating on ZK60 magnesium alloy prepared in a dual electrolyte system by micro-arc oxidation

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Rare Metals 2013年第5期32卷 459-464页

作者： Ze-Xin Wang Wei-Gang Lv Jing Chen Sheng Lu Provincial Key Laboratory of Advanced Welding Technology Jiangsu University of Science and Technology Zhenjiang Naisi New Materials Co. Ltd.

micro-arc oxidation （MAO） process was cartied out in an optimized dual electrolyte system to fabricate a compact, smooth, and corrosion resistant coating on ZK60 Mg alloy. The microstructural characteristics of coating were investigated by scanning electron microscopy （SEM） coupled with an energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）. Test of mass loss was conducted at a 3.5 % NaCl solution to assess the resistance to corrosion. The bonding strength between the coating and ZK60 substrate was evaluated using scratch experiment. The results reveal that MgA1204 and MgO are the main phases of ceramic coating obtained in the dual electrolyte system. The corrosion rate of coating prepared in the optimized dual electrolyte is only 0.0061 g.m-2.h-1, which demonstrates excellent corrosion resistance. This is mainly due to the compact, uniform coating with high bonding strength.

关键词： ZK60 magnesium alloys micro-arc oxidation Characterization Dual electrolyte system