Effect of microstructure of a NiCoCrAlY coating fabricated by high-velocity air fuel on the isothermal oxidation

• DOI: 10.1016/j.corsci.2019.108126
• Publication Date: 2019-07-30T13:23:09Z
• Authors: Jie Lu; Han Zhang; Ying Chen; Xiaofeng Zhao; Fangwei Guo; Ping Xiao
• Keywords: Isothermal process

Abstract The effect of grain size and porosity of a NiCoCrAlY coating fabricated by high-velocity air fuel on the isothermal oxidation behavior is studied. To understand this effect, the microstructure of coating, the chemistry and microstructure of thermally grown oxides (TGO), the phase transformation of alumina, the oxidation rate, and the TGO stress are investigated. It is demonstrated in this study that the oxidation and spallation resistance of TGO are predominantly determined by the porosity rather than grain size for the long term oxidation, although the nanoscale γ-grains can facilitate the earlier establishment of α-Al2O3 scale.