Original paper(Vol.47 No.7 pp.665)

Basic study of oxidation behavior of zirconia thermal barrier coating at high temperature

Itoh Yoshiyasu; Takahashi Masashi; Ishiwata Yutaka; Nagata Kohsoku

Abstract:Thermal barrier coating (TBC) had been already applied to the hot section parts of gas turbines, such as a bucket and a combustor. It is thought that TBCs are in dispensable for the gas turbines along with cooling technology. It is now desired to give higher durability to TBCs so as to endure higher combustion temperature. The object of this study is to clarify the oxidation behavior of Atmospheric Plasma Spraying TBC at high temperature.
The experimental results showed that the oxidation layer was formed mainly of alumina at the interface between the yttria stabilized zirconia top coating and MCrAlY bond coating. There was a tendency that the oxide layer growth increased with increasing heating temperature and heating time. It was also indicated that the oxide layer growth followed a 0.45 power time law. The Arrhenius type temperature dependence for the rate constant of oxide layer growth was confirmed. Finally, the long time estimation of oxide layer growth behavior was conducted by the simulation analysis.

Key Words:thermal barrier coating, zirconia, atmospheric plasma spray, MCrAlY bond coating, sintering, linear shrinkage, shrinkage stress