Combined effect of Y2O3 nanoparticles and Si second-phase oxide on microstructure and wear resistance of plasma-clad steel coating

Abstract

Alloy steel 17Cr2NiSiMo coatings with small amounts (<1 wt%) of added Y2O3 nanoparticles are fabricated by plasma-transferred arc. The combined effect of the Y2O3 nanoparticles and Si-oxide second-phase particles on microstructure, sliding wear resistance, and wear weight loss of the alloy steel coating are investigated. The Y content in the spherical Si-oxide particles is found to increase with the addition of Y2O3 nanoparticles, as Si provides second-phase oxide particles for Y to accumulate in the coating material during the rapid cooling solidification. Thus, the Fe-based coating is refined and purified, resulting in a low defect or slag concentration. The wear mechanism of the modified coating transforms from third-body interaction and plastic deformation to slight peeling, as dendritic grains in the coating are transformed into equiaxed grains. The wear performance of the modified coating is obviously enhanced with the addition of 0.4 wt% Y2O3 nanoparticles, as indicated by the reduction of its wear weight loss to 20.55% and increase of its relative wear resistance to 25.87%.