Improving oxidation resistance and thermal insulation of thermal barrier coatings by intense pulsed electron beam irradiation

Abstract

In this paper, intense pulsed electron beam was used for the irradiation treatment of 6–8% Y2O3-stablized ZrO2 thermal barrier coating prepared by electron beam-physical vapor deposition to achieve the “sealing” of columnar crystals, thus improving their thermal insulation properties and high temperature oxidation resistance. The electron beam parameters used were: pulse duration 200μs, electron voltage 15kV, energy density 3, 5, 8, 15, 20J/cm2, and pulsed numbers 30. 1050°C cyclic oxidation and static oxidation experiments were used for the research on oxidation resistance of the coatings. When the energy density of the electron beam was larger than 8J/cm2, ZrO2 ceramic coating surface was fully re-melted and became smooth, dense and shiny. The coating changed into a smooth polycrystalline structure, thus achieving the “sealing” effect of the columnar crystals. After irradiations with the energy density of 8–15J/cm2, the thermally grown oxide coating thickness decreased significantly in comparison with non-irradiated coatings, showing that the re-melted coating improved the oxidation resistance of the coatings. The results of thermal diffusivity test by laser flash method showed that the thermal diffusion rate of the irradiated coating was lower than that of the coating without irradiation treatment, and the thermal insulation performance of irradiated coating was improved.