The importance of intimate inter-crystallite bonding for the plasma erosion resistance of vacuum kinetic sprayed Y2O3 coating

In this work, the importance of inter-crystallite bonding in plasma resistant Y2O3 coating deposited by vacuum kinetic spray (VKS) was studied. The inter-crystallite bonding in VKS induced by room temperature consolidation (RTIC) was comparatively analyzed in different coatings using surface hardness data and plasma erosion resistance of the coatings was evaluated using inductively coupled plasma (ICP) etching tests. By a simple heat-treatment of the feedstock powder, a dense and stable Y2O3 coating can be readily achieved. The microstructural features of this coating showed the dense structure of feedstock particles promoted the RTIC process during VKS. It is elucidated that there existed a strong positive linear relationship between hardness and plasma erosion resistance of the Y2O3 coating. The intimate inter-crystallite bonding, which was evaluated by surface hardness, contributed to the significant improvement of plasma erosion resistance of the Y2O3 coating. Through the relationship, which is suggested in this study, the link between feedstock particle microstructure, coating microstructure, mechanical properties, and plasma erosion resistance can be consistently understood. •Plasma erosion resistant Y2O3 coating was fabricated on aluminum 6061 alloy substrate using vacuum kinetic spray (VKS).•Dense structure of feedstock particle promoted room temperature consolidation.•Inter-crystallite bonding contributed to improve plasma erosion resistance of coating•There existed a positive linear relationship between hardness and plasma erosion resistance of VKS Y2O3 coating.