Thermal and stress analysis of thermal barrier coatings

An analysis has been performed that predicts the thermomechanical behavior of thermal barrier coated specimens. The analysis predicts the behavior during both plasma spray coating application and burner rig testing conditions simulating engine operation. The analysis was accomplished through utilization of one-dimensional through thickness and two-dimensional finite element calculations. The results of these calculations showed that specimens with a substrate control temperature between 300 F and 600 F would be optimum. Controlling substrate temperature was found to have a more dominant effect on the mechanical strains than the ceramic or substrate thicknesses. The predicted stresses and mechanical strains at the bond-coating interface are large enough to cause cracks in this region where post-test observations have determined coating failures originate.