Abstract Two kinds of Ca 3 RE 3 Ti 7 Ta 2 O 26.5 (RE = La and Sm) oxides were prepared via pressureless sintering at 1873 K for ten hours. The synthesized samples have single pyrochlore-type structure as displayed by XRD. Owing to the relative stronger phonon scattering, the Ca 3 Sm 3 Ti 7 Ta 2 O 26.5 has lower thermal conductivity as compared with that of Ca 3 La 3 Ti 7 Ta 2 O 26.5 . Due to its relative greater average interionic distance, the Ca 3 La 3 Ti 7 Ta 2 O 26.5 shows higher thermal expansion coefficient than Ca 3 Sm 3 Ti 7 Ta 2 O 26.5 . The synthesized Ca 3 RE 3 Ti 7 Ta 2 O 26.5 (RE = La and Sm) oxides also perform excellent phase-stability up to 1473 K.

中文翻译：

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新型烧绿石型 Ca 3 RE 3 Ti 7 Ta 2 O 26.5 (RE=La, Sm) 氧化物的热物理性质

摘要 采用1873 K、10小时无压烧结制备了两种Ca 3 RE 3 Ti 7 Ta 2 O 26.5 (RE = La和Sm)氧化物。如XRD所示，合成的样品具有单一烧绿石型结构。由于声子散射相对较强，Ca 3 Sm 3 Ti 7 Ta 2 O 26.5 的热导率低于Ca 3 La 3 Ti 7 Ta 2 O 26.5 。由于其相对较大的平均离子间距，Ca 3 La 3 Ti 7 Ta 2 O 26.5 显示出比Ca 3 Sm 3 Ti 7 Ta 2 O 26.5 更高的热膨胀系数。合成的 Ca 3 RE 3 Ti 7 Ta 2 O 26.5 (RE = La 和 Sm) 氧化物在高达 1473 K 的温度下也具有出色的相稳定性。