The effect of silicon on thermal shock performance of aluminide-thermal barrier coatings

The failure of air-plasma-sprayed thermal barrier coatings (APS TBCs) with conventional pack aluminide and slurry Si-modified aluminide bond coats on superalloy In-738LC was investigated during a thermal-shock test. Thermal shock experiments consisted of rapid thermal cycling between 1100 °C and 300 °C for 120 times. It was found that the lifetime of APS TBCs on aluminide bond coats can be extended by introducing silicon into aluminide structure. Silicon improved the bond coat oxidation resistance as well as the stability of β-NiAl phase, which is critical to the coating life enhancement.