University of California Energy Institute

Studies of high-temperature morphological evolution of controlled-geometry surface cavities and of controlled-geometry internalized pores etched into (100) and (111) surfaces of yttria-stabilized zirconia (YSZ) have been conducted. Results show significant crystallography-dependent variations in the morphologies and evolution rates. The terraceledge structures on (100) and (111) YSZ surfaces differ substantially. Internalized pores that are largely or partially bounded by {111} surfaces are particularly stabilized with regard to shape relaxation and axial instability. The results suggest that controlled variation of thermal barrier coating (TBC) texture and microstructure could result in significant changes in stability and lifetimes.