Comparative study of the slurry erosion behavior of laser cladded Ni-WC coating modified by nanocrystalline WC and La2O3

The erosion performance of laser cladded Ni-60 %WC coatings subjected to a controllable abrasive water jet (AWJ) was investigated. The erosion resistance of Ni-60 %WC coatings at varied linear laser energy (from 315 to 700 J/mm) was examined under different impinging angles of a slurry jet. The chemical composition of coatings was modified by nanocrystalline WC powder and the rare earth element (La2O3). The erosion value of Ni-60 %WC was reduced to 40 % by decreasing the laser energy from 700 to 315 J/mm. Synthesized coatings with optimal weight fraction of nano-WC particles (5 %) and La2O3 (1 %) decreased the average microstructural grain size of the Ni-binder, increased the homogeneity and hardness of the coating, and consequently increased the erosion resistivity. The tribological evaluation of the erosion scars showed a log-linear relationship between coating hardness and volume loss under erosion. Adding nano-WC (5 %) and La2O3 (1 %) enhanced the bonding strength between Ni and WC and no pulled out WC particles was observed after erosion test.