Cyclic oxidation-induced cracking of platinum-modified nickel-aluminide coatings

Short cracks, extending to the interdiffusion zone, have been observed in platinum-modified nickel-aluminide diffusion coatings on single-crystal CMSX-4 superalloys after these have been subject to short (10 min) rapid thermal cycles. The cracks were revealed after removing the thermally grown oxide formed during cycling on the coating surfaces. Cracking was observed for coatings subject to thermal cycling between 1150 and 1050 °C, with and without an applied compressive stress, as well as on thermal cycling between 1150 °C and room temperature.