Thermoelectricity of CaIrO3 ceramics prepared by spark plasma sintering
Thermoelectricity of CaIrO3 ceramics prepared by spark plasma sintering
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放电等离子烧结制备CaIrO3陶瓷的热电性能
DOI：
10.2109/jcersj2.117.466
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发表时间：
2009
影响因子：
1.1
通讯作者：
T. Goto
中科院分区：
文献类型：
--
作者：
N. Keawprak;R. Tu;T. Goto
采用放电等离子烧结技术，在1273K下制备了以钙钛矿型钙钛矿型结构(PV-CaIrO_3)为主的多晶块体CaIrO_3，并在1273K、43.2K、259.2 K等温热处理后转变为钙钛矿型结构。PV-CaIrO_3样品的电导率(σ)从1.74×10~(4)Sm~(-1)降至1.45×10~4Sm~(-1)，当温度从298K升高到1023K时，σ从5.0x101Sm-1增加到9.8×102Sm-1。室温下样品的塞贝克系数(S)约为-44μVK-1,1023K时达到最大值40μVK-1。S随温度升高而减小，在600K以上几乎保持不变，约为60μVK-1。样品的热导率(κ)从2.7VK-1降至1.2K。当温度从298K升高到1023K时，PV-CaIrO_3和PV-CaIrO_3样品的无量纲优值系数(ZT)分别为0.02和0.003。分别进行了分析。
Polycrystalline bulk CaIrO3 as a main phase with minor phases of IrO2 and/or Ca2IrO4 was prepared by spark plasma sintering (SPS) at 1273 K. Metastable CaIrO3 with a perovskite-type structure (pv-CaIrO3) formed by heat-treatment at 1273 K for 43.2 ks and transformed into a post-perovskite structure (ppv-CaIrO3) by heat-treatment at 1273 K for 259.2 ks. The electrical conductivity (σ) of the pv-CaIrO3 specimen decreased from 1.74 × 104 to 1.45 × 104 Sm-1, while the σ of the ppv-CaIrO3 specimen increased from 5.0 × 101 to 9.8 × 102 Sm-1 with increasing temperature from 298 to 1023 K. The Seebeck coefficient (S) of the pv-CaIrO3 specimen was around -44 μVK-1 at room temperature and increase to the highest value of 40 μVK-1 at 1023 K. The S of the ppv-CaIrO3 specimen decreased with increasing temperature and had an almost constant value of about 60 μVK-1 above 600 K. The thermal conductivity (κ) of the ppv-CaIrO3 specimen decreased from 2.7 to 1.2 Wm-1K-1 and that of the pv-CaIrO3 specimen decreased from 1.5 to 1.2 Wm-1K-1 with increasing temperature from 298 to 1023 K. The highest dimensionless figure of merit values (ZT) of the pv-CaIrO3 and the ppv-CaIrO3 specimens were 0.02 and 0.003 at 1023 K, respectively.