Properties of Micro-Arc Oxidation Coating Fabricated on Magnesium Under Two Steps Current-Decreasing Mode

Frontiers in Materials

Lei Sun¹  Fei Ye¹  Xi-Zhi Jiang¹  Ze-Xin Wang¹  Jin-Wei Zhang¹  Sheng Lu¹  Wei-Gang Lv² 

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

关键词: properties;    micro-arc oxidation;    magnesium;    two steps current-decreasing mode;    dual electrolyte;   

DOI  :  10.3389/fmats.2020.00261

来源: DOAJ

【 摘 要 】

A concept of two-steps current-decreasing mode derived from constant current mode was developed to fabricate micro-arc oxidation (MAO) coatings on ZK60 magnesium alloy in a dual electrolyte system. The growth characteristics of coatings were analyzed by voltage-time curves, and the coating microstructures were characterized by means of scanning electron microscopy. Meanwhile, the roughness, corrosion behavior, and microhardness of MAO coatings were investigated. The results show that the MAO coatings exhibit a smooth and compact surface, and have improved hardness, higher thickness, smaller roughness, and uneven distribution of holes. Such positive characteristics result in improved corrosion resistance of MAO coatings. The coating produced under the two-steps current mode of “1.2–0.6A” shows a smaller corrosion rate of 0.1559 g/m2⋅h compared with the one produced under the other mode. The results of nanoscratch tests show that the coating fabricated by “1.2–0.6 A” mode has strong bond strength with the substrate. Under this optimized mode, the MAO process also has the lowest energy consumption of 49.8 W/(dm2⋅μm).

【 授权许可】

Unknown