Effect of Dry-ice Blasting on the Microstructure and Properties of Plasma-sprayed CoNiCrAlY Coating

摘要

Depending on the oxidation extent and the surface roughness after coating manufacturing, CoNiCrAlY coating displays different performance in thermal barrier coating systems. In this study, plasma-sprayed CoNiCrAlY coatings were treated by dry-ice blasting. Various treatment approaches of dry-ice blasting were assessed by means of comparing the coating quality in terms of cross-sectional structure, oxide concentration, surface morphology and roughness, and microhardness. The results showed that CoNiCrAlY coating including decreased oxides and smoother internal texture can be obtained in comparison with that deposited by conventional APS, no matter what type of treatment. The oxidation content differs after using different jet angle and installation location of dry-ice blasting. To some extent, dry-ice blasting has some cleaning effect on those splashed particles. However, no much change can be recognized in the top-surface morphology and surface roughness, because of the relatively small hardness of dry-ice pellets. There is a slight decrease in hardness probably resulting from the decrease in the oxide.