CMAS corrosion is one of the significant failure mechanisms for thermal barrier coatings (TBCs). In this work, the corrosion behaviors and wettability of CMAS on M-YTaO 4 at 1350 °C are studied to evaluate the M-YTaO4 ceramics’ potential to replace YSZ. The results show that the contact angles of CMAS on M-YTaO 4 with different time (1 min, 0.5 h, 4 h, 10 h and 24 h) are around 14.3° (14.4°14.4°, 14.4°, 14.3° and 14.2°, respectively), and larger than that on YSZ (8.0°, 1 min), which means the wettability of CMAS on M-YTaO 4 is worse than that on YSZ and which is benefit to improve its corrosion resistance. The thickness of reaction layer is increasing with elapsed time, but the increasing rate is decreased, and the maximum reaction thickness is 31.42 μm at 24 h. There are four main phases after reaction, which are M-YTaO 4 , M’-YTaO 4 , Ca 2 Ta 2 O 7 and Y 2 Si 2 O 7 . For the effects of lattice distortion and thermodynamics reason, M’-YTaO 4 can retain steadily at room temperature. Besides, the chemical reaction process between CMAS and yttrium tantalite is also be discussed.
The corrosion of YSZ TBCs attacked by calcium–magnesium–aluminosilicate (CMAS) is a serious problem. Yttrium tantalite (YTaO 4 ), a new kind of potential thermal barrier ceramic material, was expected to replace the YSZ to manufacture the TBCs because of its great thermophysical characteristics. In this study, porous YTaO 4 ceramic pellets, instead of actual TBCs, were used to investigate the CMAS corrosion resistance at 1250 °C. Results indicated that CMAS couldn't cover the whole surface of YTaO 4 pellets homogeneously because of low wettability between liquid CMAS and YTaO 4 , in addition, there was almost no reaction layer after 4 h reaction. The XRD results showed that M-YTaO 4 , M′-YTaO 4 , Ca 2 Ta 2 O 7 and Y 2 Si 2 O 7 were the main four phases after reaction and there was no phase containing the elements of Mg and Al. Compared with YSZ TBCs, this new kind of potential thermal barrier ceramic material showed well resistance to CMAS corrosion.
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