High Temperature Oxidation Behavior of Titanium Coated by Cathodic Microarc Electrodeposition

摘要

Cathodic microarc electrodeposition is a new method to produce oxide coatings on conductive materials. In this paper, an alumina coating up to 80 μm was fabricated on pure titanium by cathodic microarc electrodeposition technique in 0.4 mol/l Al(NO3)3 ethanol solution. The oxidation behaviors of the titanium and coated titanium were evaluated by isothermal oxidation at 973 K in air. Their microstructure, composition and phase constituents after 100 h oxidation test were analyzed by scanning electron microscope (SEM) and X-Ray diffraction (XRD). It is found that the oxidation rate of the coated titanium reduces about 4 times at 973 K. Isothermal oxidation. After oxidation test, the phase constituents of alumina coating hardly change, in which the coating consists of Y-Al2O3 and little a-Al2O3 phases. A thin dense alumina layer close to the coating/titanium substrate played a key role on suppressing the O and Ti diffusion during the isothermal oxidation. The cathodic microarc electrodeposition was an effective method to improve the oxidation resistance of titanium.