Effect of magnetron sputtered Al coating and anodization on the hot corrosion performance of Ti48Al2Nb2Cr alloy

To enhance the hot corrosion resistance for Ti48Al2Nb2Cr alloy, an Al coating was magnetron sputtered first and then anodized in fluorine-containing ethylene glycol. Before being deposited with salt, the specimen was pre-oxidized in air to generate an Al2O3-based protective layer. The hot corrosion performance of the specimen contaminated with 75 wt% Na2SO4 and 25 wt% NaCl was evaluated at 700 °C. It is shown that anodization facilitates the formation of a compact Al2O3 layer, and the magnetron sputtered Al coating can provide Al element for the continuous generation of protective Al2O3, therefore acting as a diffusion barrier to the inward diffused oxygen and salt ions as well as the outward diffused matrix elements.