Tribological properties of FeNiCr coatings with the addition of La2O3 on 1045 carbon steel

FeNiCr alloy with various amount of La2O3 powders were thermal sprayed onto 1045 carbon steel substrate. Properties of sprayed coatings were studied by an Optimol SRV oscillating friction and wear tester in a ball-on-disc contact configuration. Electron probe microscopy analysis (EPMA), X-ray photoelectron spectroscopy (XPS), were employed to this study. The results show that La2O3 can refine the microstructure effectively, and make the element distribution uniform, which leads to the improvement on the properties of the coatings. Meanwhile, the wear rate of the FeNiCr alloy with 1.5% La2O3 is smaller than other coatings. Interestingly the rare earth can reduce the friction coefficient, and act as self-lubricant in the oxide debris layer formed on the worn surface in friction. Wear mechanism of the coatings is oxidation wear and a large amount of counterpart material is transferred to the coatings.