Investigation of NiAl intermetallic compound as bond coat for thermal barrier coatings on Mg alloy

Abstract Bond coats play a significant role in manipulating the stability of 8YSZ thermal barrier coatings (TBCs) deposited on Mg alloy. In this study, the metal of Ni-Al mixture was sprayed as bond coat via reaction plasma spraying (RPS). Besides, Intermetallic compound NiAl was prepared by self-propagating high-temperature synthesis (SHS). The pure intermetallic compound NiAl was sprayed as bond coat via atmospheric plasma spraying (APS). The microstructure, composition, bond stability and corrosion resistance of the produced bond coats were investigated to find the optimal bond coat for the TBCs on Mg alloy. Results indicate that the bond coats composed of NiAl show excellent bond stability. High toughness of the RPS Ni-Al bond coat results in high tensile bond strength. The APS NiAl bond coat leads to outstanding thermal shock resistance mainly attributing to its moderate thermal expansion match, good mechanical properties and excellent corrosion resistance.