Solar Processing for the Glazing of ZrO2-Y2O3 Thermal Barrier Coatings: Reduction of Crack Initiation

Abstract

The glazing of thermal barrier coatings using concentrated solar energy has already been demonstrated, but crack initiation appeared as a major drawback of this processing. In this paper, the thermo-mechanical effects resulting from the fast heating at high temperature were modeled. Crack initiation was found to result from high temperature gradients in the ceramic coating. Experiments performed on plasma-sprayed ZrO2-Y2O3 layer showed that a significant reduction of crack initiation was achieved when the specimen was preheated at temperatures in the range 500°C–800°C. The potential of the solar processing was improved and this technique becomes competitive with conventional laser processes.