Effects of TGO growth on the interface stress distribution based on 3D pores in TBC ceramics layer

Abstract

Yttria partially stabilized zirconia sprayed by the air-plasma-spraying method is widely used to protect superalloy substrates due to its unique thermomechanical properties, still, the formation and development of thermally grown oxide (TGO) often causes crack propagation in thermal barrier coatings and leads to accidents. In this paper, effects of the thickness of the TGO layer, porosity on the heat insulation properties, surface residual stress between the ceramic layer and the TGO layer of TBCs fabricated by atmospheric plasma spraying were studied. Finite element calculations were used to study the thickness of TGO layers with different porosities after thermal shock, the thermal insulation performance of coatings at high temperatures and the three-dimensional distribution of thermal strain, especially at the interface between the lower ceramic layer and upper TGO layer. The results show that when the porosity of the ceramic coating is approximately 24.35%, the thermal insulation performance and the maximum von Mises stress of the coating layers are optimized, and the coating has the most extended service life. Theoretically, this paper is of great significance in revealing the influence of porosity on the service life of thermal barrier coatings.