Experimental simulation study of intersplat bonding formation by deposition of YSZ-splats on preheated YSZ substrate

摘要

Yttria stabilized zirconia (YSZ) splats were plasma sprayed on the YSZ substrate preheated to different temperature to examine the influence of the temperature of the underlying surface on which molten droplet impacts on deposition characteristics. The splat morphology and the bonding at the splat-substrate interfaces were examined by SEM. It was found that the crack density decreases rapidly with the increase of the temperature when the splat were formed on an YSZ substrate preheated to above 800℃. The nucleation of YSZ melt on the base of YSZ substrate grains takes place during solidification leading to the formation of the bonding between the splat and substrate when the temperature is increased to over 600℃. The substantial bonding was observed at the interface between YSZ splat and YSZ substrate as the temperature is increased to over 800℃. The results revealed that the temperature of the previous splat on which a molten droplet impacts significantly influence the formation of the interface bonding. In addition, the mechanism and condition for the bonding formation of a splat on a substrate with the identical compositions were discussed.