Enhanced TBC Performance with Nanostructured Bond Coats

A noncryogenic milling process was recently developed to produce equiaxed nanostructured NiCrAlY powders. In this study, the powders are used to deposit metal bond coats, with and without thermal barrier topcoats, via HVOF and low-pressure plasma spraying. TBCs with bond coats derived from non-cryogenically milled nanopowder show a reduction in porosity and TGO growth rate, delayed formation of mixed oxides, and a 50% increase in cycles to failure during thermal cycle testing. The presence of very fine alumina in the powder and bond coats plays a significant role in these improvements.