Oxidation Behavior of Ni-Cr Based Powder Metallurgy Composites Containing MoS₂ at High Temperatures

Ni-Cr based composite material containing 6wt% MoS2 and 15wt% tungsten was prepared by powder metallurgy method.Oxidation behavior of the composite was studied in air at 800,900 and 950 ℃ and oxidation kinetics curves were gained.The oxide morphology and microstructure were analyzed by X-ray diffraction (XRD) and SEM.The scales formed at 800 and 900 ℃ were complicated,with a layer mainly composed of Cr2O3 and a small amount of NiCr2O4.The oxidation kinetics of the composite nearly followed the parabolic oxidation law.At 950 ℃,the oxide scales formed on the oxidized composite were found to be loose.