NaF assisted preparation and the improved corrosion resistance of high content ZnO doped plasma electrolytic oxidation coating on AZ31B alloy  

作　　者：Chao Yang Jian Huang Suihan Cui Ricky Fu Liyuan Sheng Daokui Xu Xiubo Tian Yufeng Zheng Paul K.Chu Zhongzhen Wu 

机构地区：[1]School of Advanced Materials,Peking University Shenzhen Graduate School,Shenzhen 518055,China [2]Department of Physics,Department of Materials Science&Engineering,and Department of Biomedical Engineering,City University of Hong Kong,Tat Chee Avenue,Kowloon,Hong Kong 999077,China [3]Shenzhen Institute,Peking University,Shenzhen 518057,China [4]PKU-HKUST ShenZhen-HongKong Institution,Shenzhen 518057,China [5]Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China

出　　处：《Journal of Magnesium and Alloys》2024年第9期3602-3615,共14页镁合金学报（英文）

基　　金：supported by the 2022 Shenzhen sustainable supporting funds for colleges and universities(20220810143642004);Shenzhen Basic Research Project(JCYJ20200109144608205 and JCYJ20210324120001003);Peking University Shenzhen Graduate School Research Startup Fund of Introducing Talent(No.1270110273);Shenzhen postdoctoral research fund project after outbound(No.2129933651);Shenzhen-Hong Kong Research and Development Fund(No.SGDX20201103095406024);City University of Hong Kong Strategic Research Grants(SRG)(Nos.7005264 and 7005505);Guangdong-Hong Kong Technology Cooperation Funding Scheme(TCFS)(No.GHP/085/18SZ);IER Foundation(IERF2020001 and IERF2019002).

摘　　要：In the present research,the NaF assisted plasma electrolytic oxidation(PEO)is designed to fabricate the high-content ZnO nanoparti-cles doped coating on AZ31B alloy.The microstructure,phase constituents and corrosion behavior of the PEO coatings are investigated systematically.The results reveal that the introduction of NaF promotes the formation of MgF2 nanophases in the passivation layer on Mg alloy,decreasing the breakdown voltage and discharge voltage.As a result,the continuous arcing caused by high discharge voltage is alleviated.With the increasing of NaF content,the Zn content in the PEO coating is enhanced and the pore size in the coating is decreased correspondingly.Due to the high-content ZnO doping,the PEO coating protected AZ31B alloy demonstrates the better corrosion resistance.Compared with the bare AZ31B alloy,the high-content ZnO doped PEO coated sample shows an increased corrosion potential from-1.465 V to-1.008 V,a decreased corrosion current density from 3.043×10^(-5) A·cm^(-2) to 3.960×10^(-8) A·cm^(-2) and an increased charge transfer resistance from 1.213×10^(2) ohm·cm^(2) to 2.598×10^(5) ohm·cm^(2).Besides,the high-content ZnO doped PEO coated sample also has the excellent corrosion resistance in salt solution,exhibiting no obvious corrosion after more than 2000 h neutral salt spraying and 28 days’immersion testing.The improved corrosion resistance can be ascribed to the relative uniform distribution of ZnO in PEO coating which can transform to Zn(OH)2 and form a continuous protective layer along the corrosion interface.

关 键 词：AZ31B alloy Plasma electrolytic oxidation(PEO) ZnO doping NAF Corrosion resistant 

分 类 号：TG174.4[金属学及工艺—金属表面处理]