Rare-earth tantalates and niobates (RE₃TaO₇ and RE₃NbO₇) have been considered as promising candidate thermal barrier coating (TBC) materials in next generation gas-turbine engines due to their ultra-low thermal conductivity and better thermal stability than yttria-stabilized zirconia (YSZ). However, the low Vickers hardness and toughness are the main shortcomings of RE₃TaO₇ and RE₃NbO₇ that limit their applications as TBC materials. To increase the hardness, high entropy (Y_1/3Yb_1/3Er_1/3)₃TaO₇, (Y_1/3Yb_1/3Er_1/3)₃NbO₇, and (Sm_1/6Eu_1/6Y_1/6Yb_1/6Lu_1/6Er_1/6)₃(Nb_1/2Ta_1/2)O₇ are designed and synthesized in this study. These high entropy ceramics exhibit high Vickers hardness (10.9–12.0 GPa), close thermal expansion coefficients to that of single-principal-component RE₃TaO₇ and RE₃NbO₇ (7.9×10⁻⁶-10.8×10⁻⁶C⁻¹ at room temperature), good phase stability, and good chemical compatibility with thermally grown Al₂O₃, which make them promising for applications as candidate TBC materials.

中文翻译：

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用于热障用途的高熵缺陷萤石结构的稀土铌酸盐和钽酸盐

稀土钽酸盐和铌酸盐（RE ₃ TaO ₇和RE ₃ NbO ₇）由于其超低的导热性和比热稳定性更好的特性，已被认为是下一代燃气涡轮发动机中有希望的候选隔热涂层（TBC）材料。氧化钇稳定的氧化锆（YSZ）。但是，维氏硬度和韧性低是RE ₃ TaO ₇和RE ₃ NbO ₇的主要缺点，限制了它们作为TBC材料的应​​用。为了提高硬度，需要高熵（Y _1/3 Yb _1/3 Er _1/3）₃ TaO ₇，（Y_1/3 Yb _1/3 Er _1/3）₃ NbO ₇和（Sm _1/6 Eu _1/6 Y _1/6 Yb _1/6 Lu _1/6 Er _1/6）₃（Nb _1/2 Ta本研究设计合成了_1/2）O ₇。这些高熵陶瓷具有很高的维氏硬度（10.9-12.0 GPa），与单主要成分RE ₃ TaO ₇和RE ₃ NbO _7的热膨胀系数接近（7.9×10 ^-6 -10.8×10 ^-6 C室温下为^-1），良好的相稳定性以及与热生长的Al ₂ O _3的良好化学相容性，这使其有希望用作候选TBC材料。