Enhancing the oxidation resistance of nicraly bond coat by high-current pulsed electron beam irradiation

Abstract

The bond coat of a NiCrAlY thermal barrier coating plays an important role in solving the thermal expansion mismatch between a metal matrix and a ceramic layer and in improving the oxidation resistance of the whole thermal barrier coating. However, the NiCrAlY bond coat prepared by low-pressure plasma spraying is not conducive to its oxidation resistance because its lamellar structure is loose, porous and the surface is rough. To improve the oxidation resistance of the bond coat, the NiCrAlY bond coat prepared by plasma spraying was modified by high-current pulsed electron beam with different energy densities. Under the electron beam irradiation, the surface of the coating became smooth, and there was a 3–5 µm thick remelting layer on the surface. Under the irradiation, the thickness of the thermal growth oxide layer decreased, and the oxidation resistance was significantly improved, the oxidation product being mainly Al2O3.