A comparative study of DS NiCrAlY coating and LPPS NiCrAlY coating

Two thermal spraying techniques, namely, detonation gun spraying (DS) and low pressure plasma spraying (LPPS), were used to prepare different NiCrAlY coatings on a single crystal (SC) Ni-based superalloy. Microstructure, surface hardness, adhesion strength and high-temperature oxidation behavior of DS NiCrAlY coating and LPPS NiCrAlY coating were compared. The results showed that the two coatings in as-sprayed state had the same splat layer structure. Somewhat differently, oxidation reaction took place in DS process and Al2O3 sandwiched between the splats in DS NiCrAlY coating. It is found that the surface hardness of DS coatings are higher than those of LPPS coating. But the oxidation resistance of DS coating is relatively lower.