include a number of internal cooling features of a known type such as walls defining serpentine passages ribs turbulence promoters u201c turbulators u201d etc the vanes 12 can have a plurality of conventional cooling holes 18 and trailing edge slots 20 formed therein the presence of at least a specified minimum amount of material i e minimum wall thickness in the vanes 12 and the bands 14 and 16 is important to maintaining the structural integrity and aerodynamic performance of the turbine nozzle segment 10 such nozzle segments 10 and other hot section components commonly cast in one or more sections from a cobalt or nickel based superalloy which has acceptable strength at the elevated temperatures of operation in a gas turbine engine e g rene 80 rene 142 rene n4 rene n5 rene n6 rene n5 is one particularly commonly used alloy and has a nominal composition in weight percent of about 7 5 percent cobalt about 7 0 percent chromium about 1 5 percent molybdenum about 5 percent tungsten about 3 percent rhenium about 6 5 percent tantalum about 6 2 percent aluminum about 0 15 percent hafnium about 0 05 percent carbon about 0 004 percent boron about 0 01 percent yttrium balance nickel and minor elements the turbine nozzle segment 10 is coated with a tbc coating system of a known type fig2 shows a portion of one of the vanes 12 the coating system comprises a bond coat 22 and a top coat 24 of a ceramic material the thicknesses of the various layers of the tbc coating are exaggerated for illustrative clarity examples of metallic tbc bond coats in wide use include alloys such as mcralx overlay coatings where m is iron cobalt and or nickel and x is yttrium or a.