Microarc Oxidation Coatings Fabricated on Ti_3Al-Based Alloy in Silicate Electrolyte

摘要

The ceramic coatings with thickness up to 120 μm were prepared on Ti_3Al-based alloy in silicate electrolyte by microarc oxidation method. The morphology, microstructure, composition and phase constituent of the coatings were investigated. Microhardness profiles along the cross-section of the coating were determined. The maximum microhardness in the coating was about 3 times higher than that of the substrate. The thickness of the coating increased with the increasing of MAO time. There were two layers in the ceramic coatings: a dense layer and a loose layer. The coating was mainly composed of (Ti_(0.6)Al_(0.2)Nb_(0.2))O_2 phase. Scratching test revealed a good adhesion between the Ti_3Al substrate and the coating.