Enhanced structural stability and oxidation resistance of NiCoCrAlY bonding layer via Al addition

A novel Al doping was designed to enhance the structural stability and oxidation resistance of NiCoCrAlY bonding layer. Results showed that NiCoCrAlY without Al doping suffered from severe elemental inter-diffusion and rapid growth of (Ni, Co)Cr 2 O 4 spinel during high-temperature exposure, leading to poor structural stability and a high oxidation weight gain rate. However, Al doping induced the formation of a continuously dense alumina, which effectively suppressed the element inter-diffusion. Preferential oxidation of Al also suppressed rapid growth of brittle (Ni, Co)Cr 2 O 4 spinel. NiCoCrAlY with Al addition exhibited excellent structural stability and a low oxidation weight gain rate. • Structure stability and oxidation behaviors of Al doped NiCoCrAlY were studied. • Preferential oxidation of Al suppressed rapid growth of brittle (Ni, Co)Cr 2 O 4 spinel. • Al doping induced the formation of a continuously dense alumina barrier layer. • The dense alumina barrier layer greatly blocked severe elemental inter-diffusion. • Al doped NiCoCrAlY showed excellent structure stability and oxidation resistance.