Structural characteristics, oxidation performance and failure mechanism of thermal barrier coatings fabricated by atmospheric plasma spraying and detonation gun spraying

Abstract

In recent years, thermal barrier coatings (TBCs) are widely applied to the surface of gas-turbine engines to prolong the service life of high temperature components. The increase in raw material requirements and costs has led to the search for an alternative, cheaper ceramic based material to yttria stabilized zirconia (YSZ), which is the traditional TBC top coating material. In this study, CoNiCrAlY metallic bond coating powders were deposited on Ni-based superalloy substrates by the detonation gun (D-gun) process. Commercial YSZ and blast furnace slag (industrial waste) powders were deposited on the bond coating by atmospheric plasma spraying (APS) technique. TBCs were subjected to isothermal oxidation tests for 8, 24, 50, and 75 h at 800 degrees C. The microstructural properties of the TBCs were evaluated comparatively using advanced characterization techniques before and after oxidation tests. It has been observed that the coatings produced using BFS material have a potential to be used in different types of industries as a lowcost and environmental solution against high temperature oxidation conditions.