Improved high-temperature oxidation resistance of TC4 alloy by electrodeposited SiO2 coating

Thickness controllable SiO 2 coating was fabricated on TC4 alloy by electrodeposition. The oxidation behavior of TC4 alloy with SiO 2 coating was studied at 700 °C. The effect of electrodeposition time on the coating thickness, morphology, and oxidation performance was studied. Results showed that with the increase of electrodeposition time, the thickness of the SiO 2 coating almost linearly increased, while the oxidation resistance improved firstly and then decreased. During high-temperature oxidation, the SiO 2 coating could react with the substrate and strengthen the interfacial structure. To further enhance the oxidation performance, before thermal exposure to air, the SiO 2 coating protected TC4 alloy was sintered in argon. This resulted in the generation of a compact and glass-like oxide scale which could effectively prevent the inward diffusion of oxygen and the outward diffusion of titanium, therefore significantly enhancing the oxidation performance of TC4 alloy.