Abstract The origin of low thermal conductivity in niobium-containing perovskites was investigated. Therefore, dense NaNbO3 and KNbO3 ceramics were sintered by spark plasma sintering. The grain size was in the 1 to 10 µm range. NaNbO3 ceramic has shown a stable thermal conductivity circa 2.6 W m-1 K-1 from 373 to 1000 K and KNbO3, values from 2.5 to a plateau at 1.2 W m-1 K-1 since 673 K. This value is the lowest thermal conductivity reported for an oxide presenting a perovskite structure. The origin of such low thermal conductivities is indicated to be related with cation deficiency on the A-site of the niobium-containing perovskites.

中文翻译：

---

火花等离子体烧结致密 KNbO3 和 NaNbO3 钙钛矿陶瓷的低固有热导率

摘要 研究了含铌钙钛矿低热导率的原因。因此，通过放电等离子烧结来烧结致密的 NaNbO3 和 KNbO3 陶瓷。晶粒尺寸在 1 至 10 µm 范围内。NaNbO3 陶瓷在 373 至 1000 K 范围内显示出大约 2.6 W m-1 K-1 的稳定热导率，而 KNbO3 的热导率从 2.5 到 1.2 W m-1 K-1 的稳定值，自 673 K 以来该值是最低的报告了呈现钙钛矿结构的氧化物的电导率。表明这种低导热率的起源与含铌钙钛矿的 A 位上的阳离子缺乏有关。