Preparation and Degradation Behavior of Composite Bio-Coating on ZK60 Magnesium Alloy Using Combined Micro-Arc Oxidation and Electrophoresis Deposition

Frontiers in Materials

Lei Xu¹  Fei Ye¹  Ze-Xin Wang¹  Jin-Wei Zhang¹  Cheng Xu¹  Sheng Lu¹  Jun Yang¹  Wei-Gang Lv² 

[1] School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, China;Zhenjiang Naisi Advanced Materials Co., Ltd., Zhenjiang, China;

关键词: magnesium alloy;    micro-arc oxidation;    electrophoretic deposition;    composite coating;    HA;    degradation behavior;   

DOI  :  10.3389/fmats.2020.00190

来源: DOAJ

【 摘 要 】

In this work, ZK60 magnesium alloy was employed as the substrate substratum for producing micro-arc oxidation (MAO) coating which contains Ca and P. Electrophoretic deposition (ED) process was conducted on the micro-arc oxidized sample to prepare a hydroxyapatite (HA) layer on the original coating. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the phase constituents and microstructures of both MAO and MAO-ED coatings. Corrosion resistance and degradation behavior of the coatings in SBF were investigated by electrochemical tests and simulated body fluid (SBF) immersion tests. The results indicate that a dense HA layer about 5 μm in thickness had been successfully prepared on the MAO coating. After going through the ED process, the porosity of the MAO-ED coating had decreased from 5.63 to 0.81%. The Ca/P ratio of the MAO-ED coating had become 1.60, which indicates a potential biocompatibility of the material. Therefore, the MAO-ED coating can induce the deposition of bioactive products from SBF. During an immersion test of SBF for 10 days, the weight gain of MAO-ED sample continued to increase, showing that the deposition rate of the induced products is always higher than that of corrosion products before experiencing the 10 days of immersion. The deposition of induced products protects the substrate from being corroded so effectively that it ensures the good mechanical properties and biocompatibility during the initial stage of implantation. According to the changes in sample morphologies and the electrochemical measurements in SBF, a relevant degradation model has been suggested and the underlying mechanism for degradation behavior is discussed.

【 授权许可】

Unknown