High temperature oxidation and wear behaviour of powder metallurgically developed Ni-Cr-W-Al-Ti-MoS₂ composite

Abstract

Nickel-chromium matrix composites reinforced with tungsten, aluminum, titanium and molybdenum disulfides are developed by a powder metallurgy method. The high temperature oxidation properties, the friction and wear behaviour of the composites under dry sliding condition are investigated using the pin-on-disc. The oxidation behaviour of composite is studied by scanning electron microscopy (SEM), the worn surfaces and worn chips are observed by X-ray diffraction (XRD) and optical microscope. The results show that the kinetic curves of oxidation for composite obey the parabolic law, the oxide scales consist of Cr₂O₃ and NiCr₂O₄. Both the friction coefficient and wear rate of composites decrease with the increase of temperature before 400°C, but the wear rate is the highest at 600°C. The oxidative wear is the main wear mechanism for the composites.