The thermophysical properties and the molten CMAS resistance performance of Ytterbium Tantalate

The development of YSZ TBCs has been limited by the CMAS corrosion and thermophysical characteristics. The Ytterbium Tantalate (YbTaO4) ceramic was selected in this study to evaluate its potential to replace traditional YSZ. The thermal and mechanical properties of YbTaO4 show great advantages over YSZ, especially the hardness (191.3 +/- 7.6 Hv(0.3)). The CMAS hot corrosion results indicate that the maximum thickness of the reaction layer at 1350 degrees C after 24 h is similar to 16.8 mu m, which is much thinner than that of YSZ. Moreover, the porosity of the reaction layer does not increase significantly compared with the YSZ TBCs. The main product after the reaction is the Ca2Ta2O7 phase, and there is no anorthite phase after the reaction, mainly because the formation of the Ca2Ta2O7 phase consumes a lot of Ca atoms. In addition, the equilibrium contact angle of YbTaO4 is higher than that of YSZ, which indicates that the YbTaO4 possesses worse wettability. In actual conditions, low wettability is conducive to the YbTaO4 TBCs get rid of the liquid CMAS, which can effectively reduce the corrosion effect of CMAS. Furthermore, the corrosion depth and area of YbTaO4 causing by residual CMAS are also smaller due to the poor wettability. Based on the above results, YbTaO4 exhibits excellent potential to replace YSZ in preparing TBCs for the next generation aero engines.