Preparation and thermoelectric performance of Bi2Ru2O7+WO3 composite ceramics

Abstract

用RuCl3·6H2O、Bi（NO3）3·5H2O、WO3及氨水为原料,通过沉淀反应制备水合二氧化钌和氢氧化铋混合包覆的WO3粉体;再采用传统烧结工艺制备了Bi2Ru2O7+WO3复合陶瓷,并对其微观结构、形貌、热电性能进行了研究。结果表明,Ru、Bi形成了Bi2Ru2O7第二相分散于体系中,陶瓷样品的电导率随着钌元素浓度的提高而增大。当钌元素的摩尔分数低于5%时,陶瓷样品的Seebeck系数为负值,样品为n型热电材料。该陶瓷具有明显的热电性能,在573K下,浓度为5%的样品的功率因子可达0.125 66μW/（m·K2）。 The WO3 powders coated with the hydrous ruthenium oxide and bismuth hydroxide were prepared via the precipitation reaction by using the RuCl3·6H2O, Bi(NO3)3·5H2O, WO3 and ammonia as raw materials. Then the Bi2Ru2O7+WO3 composite ceramics were prepared via the conventional sintering processes. The crystalline structure, micro morphology and thermoelectric properties of the ceramics were investigated. The results showed that the Ru and Bi formed the Bi2Ru2O7 crystalline phase as a second phase, which dispersed in the ceramic system. The conductivity of the ceramics increased with the increase of the concentration of Ru increases. The Seebeck coefficient of the sample with a is negative when the ruthenium mole fraction is less than 5%, so the prepared sample should be belonged to the n-type thermoelectric oxides materials. The ceramics shown a observable thermoelectric properties. The power factor of the sample with the content of 5% was found to be 0.125 66 μW/(m·K2) at 573 K.