The Influence of Magnetron-sputtered SiO2 Coatings on the Cyclic Oxidation Behavior of γ-TiAl Alloys

Abstract

A SiO 2 coating of about 2 μm was deposited onto γ-TiAl alloys by using a magnetron-sputtering coating method. The cyclic oxidation behavior of γ-TiAl alloys was investigated at 1123 K in air. The uncoated γ-TiAl specimen showed a high oxidation rate during the initially transient period of up to 220 ks, after which, a rapid mass loss was observed due to the partial scale spallation. In contrast, the SiO 2 -coated TiAl specimen exhibited an extremely low oxidation rate. It was found that the SiO 2 coating acted as an external barrier coating, thereby being capable of significantly suppressing the oxidation of γ-TiAl alloys.