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') RETaO 4 (RE = Yb, Lu, Sc) with excellent Al 2 O 3 /SiO 2 chemical compatibility are studied. Excellent thermal insulation protection will be provided by m'RETaO 4 due to their low thermal conductivity (∼1.6 W m −1 K −1 , 900 °C) and prominent thermal radiation resistance, which is much better than those of YSZ (∼2.5 W m −1 K −1 , 1000 °C) and La 2 Zr 2 O 7 (∼2.0 W m −1 K −1 , 900 °C). The thermal expansion coefficients (TECs) are 3.0–8.0 × 10 -6 K −1 (200−1200 °C), which is suitable for T/EBCs applications. Furthermore, absence of phase transition and extraordinary chemical compatibility with Al 2 O 3 /SiO 2 up to 1500 °C indicate the potential application prospect. The documented governing mechanisms of m'RETaO 4 properties will enable researchers to promote their application in the future investigation.