利用固相反应法制备了Pb-doped Bi2Sr2Co2Oy(Bi1.6Pb0.4Sr2 Co2Oy)/Ag多晶复合热电材料,并研究了Ag含量对样品结构和热电性能的影响.X线衍射和X线能谱分析表明,Ag主要以金属单质形式存在于Bi1.6Pb0.4Sr2Co2Oy中.适量的Ag(质量分数25％)复合能显著降低样品的电阻率,而对其塞贝克系数影响很小,从而使Bi1.6Pb0.4Sr2 Co2Oy的功率因子大幅提高;继续增大Ag的质量分数(30％),一方面会抑制Bi1.6Pb0.4Sr2 Co2Oy晶粒的生长,并使其c轴织构程度变差;另一方面会引起复合物中Ag颗粒的团聚、长大,导致其功率因子下降.Bi1.6Pb0.4Sr2 Co2Oy/Ag(质量分数25％)样品973 K时功率因子2.72×10-4 W/(m·K2),比相同温度下母体材料Bi2Sr2Co2Oy的功率因子提高了近60％.以上结果表明,在对Bi2Sr2Co2Oy掺杂的基础上同时进行金属Ag颗粒复合是提高其热电性能的有效途径之一.
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