Tribological properties of Ni3Al–Cr7C3 composite coatings under liquid paraffin lubrication

Tribological properties of Ni3Al–Cr7C3 composite coatings on carbon steel lubricated with liquid paraffin were measured by using a ball-on-disc reciprocating tribotester. Effects of load, sliding speed, sliding time to the coatingsʹ tribological properties were investigated. The worn surface of Ni3Al–Cr7C3 coatings was examined using scanning electron microscopy (SEM), electron probe microscopy analysis (EPMA) and X-ray photoelectron spectroscopy (XPS). It shows that the wear rate of Ni3Al–Cr7C3 coatings is lower than the bearing steel and the Ni3Al coating at the same test conditions. Wear rate and friction coefficient of Ni3Al–Cr7C3 coatings varies with the load, sliding speed, sliding time and Cr7C3 phase content. The results of the experiments were well explained by analyzing wear and friction mechanism of Ni3Al–Cr7C3 coatings under different tribological parameters.