微波合成Ca_3Co_4O_9热电材料的微观结构和性能

Microstructure and thermoelectric properties of Ca_3Co_4O_9 materials prepared by microwave technique

利用微波技术合成了Ca3Co4O9化合物,考察了微波加热时间对产物纯度和微观结构的影响;再利用微波及常规烧结技术制备了Ca3Co4O9热电陶瓷片,考察了烧结时间、烧结方式对材料微观结构和热电性能的影响.结果表明:二次微波烧结30 min制备的热电陶瓷片在所测试温度范围内具有低电阻率、高塞贝克系数及最佳功率因子,其中966 K时微波产物的最大功率因子为0.141 m W/m K2,而常规高温烧结产物的功率因子为0.120 m W/m K2.

Ca3Co4O9 compound was synthesized by microwave heating technique, the influence of irradiation time on purity and microstructures of the product was investigated as well. In addition, the Ca3Co4O9 thermoelectric ceramics were prepared by microwave- and conventional-sintering techniques, the influence of sintering methods and time on microstructures and thermoelectric properties of the samples was analyzed. The results indicate that the ceramics prepared by double microwave-sintering exhibit low resistivity, high Seebeck coefficient and optimal power factors in the applied temperature range. For instance, the maximal power factor at 966 K is 0.141 mW/mK^2 for the microwave-sintered sample, while 0.120 mW/mK^2 for the conventional-sintered sample.