Detection And Change Regulation Of Internal Stress In Thermal Barrier Coatings At Different Service Stages Under High Temperature

The thermal barrier coatings(TBCs)have complex structure and bad work environment.Its preparation process,material and service environment have important influence on the evolution of internal stress of TBCs.The thermal growth oxide(TGO)formed at the interface between Top Coating(TC)and Bond Coating(BC)is the main failure area during the service.The failure mode is closely related to the residual stress formed during the process of thermal cycle.Study and characterization of the interfacial stress state and distribution of the internal stress of the TBCs at different service stages under high temperature,it is of great significance to understand the failure mechanism and the life prediction of the TBCs.Surface stress detection of original preparation coating,high temperature oxidation coating and thermal shock coating in different service stages are realized by high temperature Raman spectroscopy,the surface stress obtained is compared with the internal stress of the finite element software simulation,the changes in the internal stress of the TBCs at different service stages are obtained.The surface stress of the TBCs at different service stages measured by high temperature Raman spectroscopy are residual tensile stress and the results are in agreement with the simulation results of computer simulation.Under high temperature environment,the internal stress increases with the increase of test temperature,and the interfacial stress is far greater than the surface stress.Under different high temperature conditions,the study shows that the thickness and internal stress of the thermal barrier coating TGO increase regularly.The internal stress level of the thermal barrier coating can reflect the thickness of the thermal barrier coating TGO to a certain extent.