Yb_yCo_4Sb_(12)/Yb_2O_3热电复合材料的高温稳定性研究  

Study on the High Temperature Stability of Yb_yCo_4Sb_(12)/Yb_2O_3 Composite Thermoelectric Material

作　　者：丁娟[1,2] 刘睿恒 顾辉[2] 陈立东[1] 

机构地区：[1]中国科学院上海硅酸盐研究所中国科学院能量转换材料重点实验室,上海200050 [2]中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室,上海200050

出　　处：《无机材料学报》2014年第2期209-214,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金重点项目(11179013)~~

摘　　要：采用高温熔融/热处理并结合SPS烧结工艺制备了Yb名义组分为0.6的Yby Co4Sb12/Yb2O3填充方钴矿复合材料,纳米或亚微米Yb2O3颗粒主要分散在方钴矿晶界上。研究了873 K下低氧分压高温处理对样品的热电性能与微结构的影响。热处理后样品的电导率、赛贝克系数、热导率基本保持不变,块体材料内部纳米与亚微米尺度微观结构未发生明显变化,未发现填充方钴矿结构中的Yb元素的"大量逸出"与氧化,材料的高温ZT值保持在1.2左右。TEM观察发现Yby Co4Sb12填充方钴矿晶粒内存在大量的位错,由位错产生的内应力有可能对Yb离子从晶格孔洞的逸出以及Yb离子和O离子的扩散产生阻碍作用,从而抑制了在高温低氧分压下Yby Co4Sb12的内氧化,使得高Yb含量的Yby Co4Sb12/Yb2O3复合材料的高温稳定性比低Yb含量填充方钴矿材料更佳。YbyCo4Sb12/Yb2O3 filled skutterudite composite with nominal compositions of y=0.6 was synthesized, in which the Yb203 particles in nanometer and/or micrometer sizes dispersed mainly on the grain boundary. The high tem- perature stability of the composite was investigated. It was found that the thermoelectric properties （elecirical conductivity, Seebeck coefficient and thermal conductivity） and the microstructure features （grain size, amount and dispersion of oxide particles）, Yb filling fractions were almost unchanged after heat treatment at 873 K for 30 d, resulting in almost un- changed maximum ZT values of about 1.2. A large number of dislocations were observed in the grain interior. The stress generated by dislocations is considered the major factor to effectively prevent the ＂escape＂ of Yb ions from the Sb-cages and to block the migration of the Yb2＋ ions and O2 ions, thus preventing the generation of oxide particles.

关 键 词：热电转换 方钴矿 纳米复合 结构演化 

分 类 号：TQ174[化学工程—陶瓷工业]