Tribological properties of laser cladding nickel-based WC reinforced Ag self-lubricating coating on RuT450 surface

Abstract

Through laser cladding, an Inconel 718-WC reinforced Ag self-lubricating coating was designed on the surface of the vermicular cast iron (RuT450) to enhance its wear resistance. The results indicated that the Inconel 718-WC-Ag wear-resistant self-lubricating coating with no cracks and no pores was manufactured by laser power of 700 W and 1000 W. The hardness of 1000 W coating was 386HV0.5, which was somewhat greater than the hardness of 700 W coating (363HV0.5). The wear rate of 1000 W coating at room temperature and 300 °C was 0.59 and 0.68 times that of 700 W coating. At room temperature, the wear rate of 700 W coating and 1000 W coating was 0.43 and 0.25 times that of the substrate RuT450. The two coatings outperformed the substrate in terms of wear resistance due mostly to the interaction between Ag and M23C6, MC, and M2C type carbides. The 700 W coating's main wear mechanisms were severe fatigue wear, abrasive wear, and minimal oxidation wear. Minor fatigue wear, abrasive wear, and oxidation wear made up the majority of the wear mechanism of 1000 W coating. At 300 °C, the wear rates for the 700 W and 1000 W coatings was 0.24 and 0.16 times that of the substrate RuT450. The remarkable wear resistance of the two coatings was mostly due to the interaction of Ag with NiO, Ag2O, and Ni2O3 type oxides. The plastic deformation of the wear surface of both coatings was relatively light compared to the substrate RuT450, and only small grooves and furrows on the surfaces of the two coatings were visible.