Elevated temperature oxidation behavior of
HVOF sprayed TiB2 cermet coating
(Department of Materials Engineering, Faculty of Engineering, Shahid Chamran University, Ahvaz, Iran)
Abstract: Oxidation behaviors of Ni(Cr)-TiB2 coating deposited by HVOF technique were studied at 800, 900 and 1 000 ℃ in air. The microstructures of as-sprayed and oxidized coatings were characterized by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). After oxidation at 800 ℃, a thin and adherent oxide layer was formed on the surface of the coating. With increasing exposure temperature, the thickness of the oxide layer increased; and at 1 000 ℃ the oxide layer separated from the coating. Investigation of the kinetics of oxidation by using the thermogravimetric analysis (TGA) technique shows a parabolic oxidation rate.
Key words: TiB2; cermet coating; thermal spraying; oxidation