Research on oxidation kinetics of CoNiCrAlY coatings in pure steam environment

Abstract

The investigation carried out on CoNiCrAlY coatings oxidation behavior in both pure steam and atmospheric environments using cyclic oxidation experiments at 1100 °C revealed distinct variations in the oxidation kinetics. In pure steam, the early stage of exposure causes an acceleration in the growth rate of TGO, which however stabilizes after 92 h. Steam has an impact on the movement of species at TGO grain boundaries, thus aiding internal O diffusion and the creation of a homogeneous α-Al2O3 scale. However, atmospheric oxidation of TGO results in a complicated double-layer oxidation configuration and worsens mixed oxide layer formation at the peak.