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

S. Cengiz, M. Tarakci, Y. Gencer, A.O. Devecili and Y. Azakli Gebze Institute of Technology, Department of Materials Science and Engineering, 41400 Gebze, Kocaeli, Turkey

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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 α-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 γ-Al2O3 phases were formed for 40 min and α-Al2O3 phase was additionally formed for 80 min and 120 min coating time. The coating thickness increased from 38 μm (40 min) to 115 μm (120 min) while the surface roughness (Ra) increased from 5 μm (40 min) to 9 μm (120 min).

DOI: 10.12693/APhysPolA.123.445 PACS numbers: 81.15.-z, 81.05.Bx