Influence of thermal cycling on residual stresses in zirconia thermal barrier coatings produced by electron beam-physical vapor deposition

Flat specimens and aircraft turbine engine blades were coated with partially stabilized zirconia by electron beam-physical vapor deposition. Residual stresses of these thermal barrier coatings were measured before and after thermal cycling by x-ray stress analysis. All flat specimens and blades showed compressive residual stresses. Stress values in the longitudinal direction were significantly greater than those measured in the transverse direction. No changes of stress states and line widths were observed after thermal cycling. The specimens showed considerable differences in texture which made evaluation of the stress measurements difficult and which may have influenced degradation behavior during thermal cycling.