Oxide Based Ceramic Coating on Al-4Cu Alloy by Microarc Oxidation

Abstract

In this study the Al Cu aluminum alloy with 4 wt% Cu was prepared under controlled atmosphere and coated by microarc oxidation technique for the durations of 40, 80, and 120 min. The phase composition, surface roughness and hardness of the coating were characterized by X-ray diffraction, scanning electron microscopy, profilometry. The outer region contains larger sized porosities while fine porosities were formed in the inner dense region of the coating. The longer coating duration resulted in dense inner region with finely distributed alpha-Al2O3 precipitates. The presence of Cu in the outer region is not significant while the presence of Si in inner region was lower than in the outer region. Mullite and gamma-Al2O3 phases were formed for 40 min and alpha-Al2O3 phase was additionally formed for 80 mm and 120 min coating time. The coating thickness increased from 38 mu m (40 min) to 115 mu m (120 min) while the surface roughness (R-a) increased from 5 Ana (40 min) to 9 mu m (120 min). DOI: 10.12693/APhysPolA.123.445