Oxidation‐Based Model for Thermal Barrier Coating Life

TLDR

Reproducible specimen preparation is essential for reliable thermal barrier coating life assessment. The study proposes a procedure to model the life of thermal barrier coatings in high‑temperature environments. The model calculates cycles‑to‑failure as a function of heating cycle duration, assuming oxidation is the primary time‑dependent degradation mechanism and that oxidation‑induced strains combined with cyclic strains drive slow crack growth in the ceramic layer. Calculated lifetimes agree well with experimental furnace tests, indicating that an oxidation‑based approach is promising.

Abstract

A procedure is described for modeling the lives of thermal barrier coatings subjected to high‐temperature environments. The model is used to calculate cycles‐to‐failure as a function of heating cycle duration. It is based on the presumption that oxidation is the single important time‐dependent factor which limits the life of these coatings, and that oxidation‐induced strains combine with cyclic strains to promote slow crack growth in the ceramic layer. Good agreement is obtained between calculated and experimental lives for specimens tested in a furnace. This shows that an oxidation‐based approach is promising. The importance of reproducible specimen preparation is also discussed.