Mechanical and thermal properties of RETaO4 (RE = Yb, Lu, Sc) ceramics with monoclinic-prime phase

As candidate thermal/environmental barrier coatings (T/EBCs), the structure characteristics and comprehensive properties of monoclinic-prime (m') RETaO4 (RE = Yb, Lu, Sc) with excellent Al2O3/SiO2 chemical compatibility are studied. Excellent thermal insulation protection will be provided by m'RETaO4 due to their low thermal conductivity (similar to 1.6 W m(-1) K-1, 900 degrees C) and prominent thermal radiation resistance, which is much better than those of YSZ (similar to 2.5 W m(-1) K-1, 1000 degrees C) and La2Zr2O7 (similar to 2.0 W m(-1) K-1, 900 degrees C). The thermal expansion coefficients (TECs) are 3.0-8.0 x 10(-6) K-1 (200-1200 degrees C), which is suitable for T/EBCs applications. Furthermore, absence of phase transition and extraordinary chemical compatibility with Al2O3/SiO2 up to 1500 degrees C indicate the potential application prospect. The documented governing mechanisms of m'RETaO4 properties will enable researchers to promote their application in the future investigation. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.