Study on fatigue life prediction of thermal barrier coatings for high-power engine pistons

Thermal barrier coatings (TBCs) have been widely used in high-power engine components because of their excellent thermal insulation properties. In this study, microcrack growth and fatigue life analysis of TBCs were carried out based on thermal shock tests of TBCs samples. Scanning electron microscopy (SEM) was used to observe the spallation and vertical crack growth behavior of TBCs during the tests. The fatigue life prediction model applied to piston TBCs was developed by modifying the Paris equation with the sintering of the coating and the effect of a thermally grown oxide (TGO) layer being considered. The model was calibrated by conducting tests on piston TBCs, and the forecasting error was less than 15%, indicating that the prediction model is both practical and effective. The results of this study provide a service life evaluation and test method for TBCs on pistons, which can be utilized to guide piston TBCs design.