Effect of Ni in SiO2 coating on the oxidation resistance of TiAl alloy at 900 C

In this study, a novel SiO2 coating with the incorporation of nickel was prepared on Ti48Al2Nb2Cr alloy by coelectrodeposition. The effect of Ni in SiO2 coating on the oxidation resistance of Ti48Al2Nb2Cr alloy at 900 & DEG;C was investigated. Due to the incorporation of nickel, the high temperature performance of the SiO2 coating is promoted. For the Ni-modified SiO2 coating, diffusion of oxygen to the substrate is effectively inhibited by a compact oxide scale composed of SiO2 outer layer, Al2O3 middle layer, and Ti5Si3 inner layer. The incorporated Ni reinforces the structure and withstands the stress change of the SiO2 coating. Moreover, the occurrence of cracking is impeded by NiO which is formed during oxidation.