A durable protective coating may be formed by applying a thin layer of
metastable alumina to a bond coating on a substrate. A thermal barrier
coating may then be applied to the metastable alumina and the resulting
part may be heat treated to transform the metastable alumina to a mixed
alpha alumina having particles of the thermal barrier coating, such as
zirconia in the case of an yttria stabilized zirconia thermal barrier
coating, dispersed therein. The resulting thermal barrier coating may
inhibit microbuckling of the thermally grown oxide scale that grows over
time at the thermal barrier coating-bond coating interface.