Oxidation behavior of double-ceramic-layer thermal barrier coatings deposited by atmospheric plasma spraying and suspension plasma spraying
Yuxiang Zhao, Yuxue Ge, Xiaochao Jin, Denise M. Koch, Robert Vaßen, Yao Chen, Xueling Fan
Abstract
This paper focuses on the oxidation behavior of novel double-ceramic-layer thermal barrier coatings (DCL TBCs) deposited by atmospheric plasma spraying (APS) and suspension plasma spraying (SPS). Four kinds of APS-SPS DCL TBCs with dense/porous columnar structured or vertically cracked microstructures were prepared. The oxidation behavior of the APS-SPS DCL TBCs were tested and the underlying mechanisms were further discussed. Results showed that the developed APS-SPS DCL TBCs have a better oxidation resistance than the single layer SPS TBC that was tested for comparison. In the long-term oxidation, the thermally grown oxide (TGO) can be divided into two layers, the outer mixed oxide and inner Al 2 O 3 layer, in which the growth rate of mixed oxide in TGO changed during oxidation. In terms of the oxidation rate and oxidation lifetime, segmented APS-SPS TBCs has a slightly better performance than the columnar APS-SPS TBCs. Among the four different APS-SPS TBCs, the segmented dense APS-SPS TBCs with low vertical crack density appears to have more potential to be used for industrial application.