Heat treatment effect on coating shock resistance of thermal barrier coating system with different types of bond coat

Abstract

The effect of heat treatment, growth of the TGO layer , oxidation of bond coat, and the impact of the presence of two bond coats on the TBC's thermal shock resistance has been investigated experimentally. TGO oxide layers were created with two-time heat treatment of 12 and 24 h at 1000. Then the thermal shock test was performed on the APS/APS and HVOF/APS/APS samples. The results show that the use of two BCs and the presence of a thin TGO layer has a good effect on TBC performance. The presence of two BC layers increased the shock resistance by an average of 37.2%. 12 h heat treatment caused a 14.0% and 17.4% shock resistance increase in samples with the HVOF/APS/APS layer and APS/APS layer, respectively. 24 h heat treatment decreased the samples' performance by 6.7% and 10.2% for samples with two BC and one BC, respectively. • Based on the experimental results, the thermal shock resistance of two different types of TBCs was investigated. • The effect of primary heat treatment and the TGO layer's growth on the coating's behavior against thermal shock was studied. • Microstructural changes and fractures in the TBC layers under thermal shock were studied by using SEM images. • The influence of the primary heat treatment and the effect of HVOF and APS bond coat on the behavior of TBC are discussed.