Date of Completion


Embargo Period



Michael W. Renfro, Maurice Gell

Field of Study

Mechanical Engineering


Master of Science

Open Access

Open Access


Thermal barrier coatings (TBCs) are important in increasing performance and extending the life of gas turbine engine hot parts. Over the course of thermal cycling and engine operation, the coatings eventually spall off exposing superalloys to extreme temperatures. In this thesis, two aspects involving thermal barrier coating life prediction were explored. The first was by making use of stress measurements in the thermally grown oxide (TGO) to predict lives of samples subjected to non-constant furnace testing. This work used data from an earlier thesis and for the first time developed specific strategies to predict remaining life in the face of changing peak temperatures and hold times. Secondly, the relation between stress and coating life in two new coating systems was explored experimentally with furnace cycling and TGO stress measurements which was done as input for a potential industrial application to aircraft maintenance. Because there was an issue with one of the two samples types supplied, the project was expanded to understand the nature of the defect in some of the samples provided. All research was conducted in service of the goal of allowing TGO stress measurements to be used to predict remaining life of actual engine parts.

Major Advisor

Eric H. Jordan