No abstract

No abstract

Development of electron beam physical vapor deposited (EB‐PVD) thermal barrier coatings (TBC) aims at low conductivity, increased temperature capability, and longer life. Considerable progress has been achieved by comprehensive understanding of the evolvement of the porous microstructure in columnar ceramic topcoats and its application to tailoring optimized micro‐structures. New ceramic compositions such as alternative stabilizers in zirconia, hafnia modified coatings, and pyrochlores are addressed. They have demonstrated their potential for future TBC applications. New results of both microstructure and chemistry are presented together with a summary of recent research results.

Abstract

No abstract

No abstract

No abstract

Electron‐beam physical‐vapor‐deposited thermal barrier coatings consisting of ZrO2 stabilized by 7 wt% Y2O3 were investigated in regard to phase transformation after annealing. Free‐standing ceramic layers were heat‐treated in air, for up to 200 h, in the temperature range 1200°—1400°C and then analyzed by X‐ray diffractometry. Based on information obtained from the {111} and {400} peaks, the phase composition and the Y2O3 content in the phases were calculated. At the start of transformation, small grains of a low‐Y2O3t phase and a c phase formed. After >30 h at 1300°C and at 1400°C, a mixture of a t phase deficient in Y2O3, an m phase, and a c phase formed after cooling, with the Y2O3 contents in the phases roughly predicted by the phase diagrams. The results of the present study are discussed here in detail and compared with data for plasma‐sprayed coatings.