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采用常压固相烧结法制备B i2SrCaCo2Oδ和B i2Ca2Co2Oδ氧化物热电材料,研究Sr、Ca位替代或掺杂对陶瓷材料制备条件、晶体结构和电学性能的影响。通过XRD、SEM、EDS等表征技术及标准四探针法研究了烧结温度和晶体结构参数对陶瓷物相、显微组织形貌和电学性能的影响。结果表明同族元素Ca、Sr的互相替代,B i系Co基氧化物仍然呈现岩盐型层片状晶体结构,且一定程度上表现出插层替代的特性,仍具有明显的c轴择优取向。由于Ca元素替代Sr元素,c轴尺寸减小,同时烧结温度上升;电阻率-温度关系图显示,样品呈现出明显的半导体特性。
B i2SrCaCo2Oδ and B i2Ca2Co2Oδ oxide thermoelectric materials were prepared by atmospheric pressure solid-state sintering. The effects of Sr or Ca substitution or doping on the preparation conditions, crystal structure and electrical properties of ceramic materials were investigated. The influence of sintering temperature and crystal structure parameters on the phase, microstructure and electrical properties of ceramic was investigated by XRD, SEM, EDS and other four characterization techniques. The results show that substitutions of Ca and Sr in the same group elements, Co-based oxides of B i series still show rock salt-lamellar crystal structure and exhibit intercalation substitution to a certain extent, and still have obvious c-axis preferred orientation. As the Ca element replaces the Sr element, the c-axis size decreases and the sintering temperature increases. The resistivity-temperature relationship shows that the sample shows obvious semiconducting properties.