Alumina scale growth and degradation modes of a TBC system

Abstract

AbstractThe evolution of a thermal barrier coating system was followed during exposures at high temperature (1100°C) and under various thermal and mechanical loading conditions. The TBC system is composed of an EB-PVD yttria partially stabilised zirconia topcoat (TC) and a platinum nickel aluminide bondcoat (BC) deposited on a single crystal nickel based superalloy. Depending on the kind of heat treatment (isothermal or thermo-mechanically cycled), different types of defects (pores, cracks, re-oxidation), were observed at the BC/TGO interface, the TGO/TC interface or in the alumina scale. Damage processes were identified and discussed according to the type of imposed heat treatment.Keywords: thermal barrier coatingalumina scale growth