CMAS corrosion resistant of La3+-Yb3+-Ce4+ co-doped ZrO2 based TBCs: Experimental and theoretical research

The CaO-MgO-Al2O3-SiO2 (CMAS) corrosion resistance of La3+-Yb3+-Ce4+ co-doped ZrO2 (LYZC) ceramic was systematically discussed via experiment and first-principles calculation. Results demonstrate that at the CMAS/ RE-ZrO2 interface, RE is dissolved in molten CMAS to form some RE-apatite particles, which effectively inhibits CMAS penetration. Compared with La3+ doped ZrO2 (LZ), LYZC owns a better ability to maintain the coating microstructure under CMAS corroded, which is conducive to alleviating CMAS penetration. This conclusion is also confirmed by the low diffusion coefficients (D) of RE and Zr in CMAS/LYZC(111), which are only 2.305-5.556 x 10-8 m/s and 2.694-3.421 x 10-8 m/s, respectively. Furthermore, the small electrostatic potential difference (Delta V = 1.578-1.654 eV) of the CMAS/LYZC(111) terminal layer suggests that molten CMAS does not easily adhere to the LYZC surface.