Effect of Current Ratio on Plasma Electrolytic Oxide Coatings on Mg-Al Alloy
Ceramic coatings were synthesized on pure Mg and binary Mg-7.1wt%Al alloy by plasma electrolytic oxidation (PEO) technique, and the effect of current ratio, C2/C1, ranging from 0.2 to 0.85 on their mechanical and electrochemical properties was investigated. As the C2/C1 ratio increased, the thickness of the coating layer increased, while surface roughness was almost unchanged. The hardness and wear resistance had a marked tendency to increase with increasing C2/C1 ratio and Mg-Al alloy showed higher hardness and wear resistance at all C2/C1 ratios compared to pure Mg. The weight loss of the pure Mg and Mg-Al alloy in 3.5%NaCl solution was reduced by coatings. However, it had no dependence on the C2/C1 ratio. The wear resistance of the coated Mg-Al alloy was better than that of the coated pure Mg.
Byung Tae Ahn, Hyeongtag Jeon, Bo Young Hur, Kibae Kim and Jong Wan Park
S. Y. Chang et al., "Effect of Current Ratio on Plasma Electrolytic Oxide Coatings on Mg-Al Alloy", Solid State Phenomena, Vols. 124-126, pp. 767-770, 2007