The Influence of Magnetron-sputtered SiO<SUB>2</SUB> Coatings on the Cyclic Oxidation Behavior of γ-TiAl Alloys

Abstract

A SiO2 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 SiO2-coated TiAl specimen exhibited an extremely low oxidation rate. It was found that the SiO2 coating acted as an external barrier coating, thereby being capable of significantly suppressing the oxidation of γ-TiAl alloys.