Oxidation behavior of bulk amorphous Ni57Ti18Zr20Si3Sn2 coatings between 473 and 973Â K in air

Amorphous Ni57Ti18Zr20Si3Sn2 coating was sprayed onto a mild steel substrate using a kinetic spraying method, and the oxidation behavior of the coating was examined at temperatures ranging from 473 to 973 K in air. The coating was oxidized primarily to NiO, TiO2 and tetragonal-ZrO2. The coating did not offer adequate oxidation resistance, and its oxidation progressed primarily by the inward diffusion of oxygen, becoming more severe with increasing oxidation time and temperature. During oxidation, the amorphous coating crystallized to orthorhombic Ni10(Zr,Ti)7 and γ-Ni. At 973 K, the coating had completely transformed to a crystalline phase, and the surface oxidized substantially to form an oxidized region.