ceramic layer or tbc on a superalloy substrate 22 that is typically the base material of the blade 10 in fig1 suitable materials for the substrate 22 and therefore the blade 10 include equiaxed directionally solidified and single crystal nickel and cobalt base superalloys the bond coat 24 adheres the ceramic layer 26 to the substrate 22 through the growth of an alumina scale 28 when the bond coat 24 is exposed to an oxidizing atmosphere such as during high temperature exposures in air and deposition of the ceramic layer 26 as shown the ceramic layer 26 has a strain tolerant grain structure of columnar grains 30 achieved by depositing the ceramic layer 26 using physical vapor deposition techniques known in the art such as ebpvd a preferred material for the ceramic layer 26 is an yttria stabilized zirconia ysz a preferred composition being about 4 to about 8 weight percent yttria though other ceramic materials could be used such as yttria nonstabilized zirconia or zirconia stabilized by magnesia ceria scandia or other oxides the ceramic layer 26 is deposited to a thickness that is sufficient to provide the required thermal protection for the underlying substrate 22 and blade 10 generally on the order of about 75 to about 300 micrometers as an overlay coating little interdiffusion occurs between the bond coat 24 and the.