溶胶-凝胶法制备（La1-xSrx）2Ce2O7-x及热物理性能研究

溶胶-凝胶法制备（La_1-xSr_x）₂Ce₂O_7-x及热物理性能研究

摘要: 采用溶胶-凝胶法合成（La_1-xSr_x）₂Ce₂O_7-x系列组分样品.研究结果表明：当Sr的掺杂量（x）小于10 %时，（La_1-xSr_x）₂Ce₂O_7-x系列组分样品都是缺陷萤石结构.随着温度的升高，样品的热膨胀系数（TEC）增大，而热导率（TC）呈减小趋势.在一定温度下，（La_1-xSr_x）₂Ce₂O_7-x的TEC随x的增大而增大；当Sr掺杂量x在0~7.5 %之间增加时，样品的热导率不断减小，至x=7.5 %时达到极小值，然后随x的增大，样品的TC又明显增大.

Abstract: Series of Sr -doping La₂Ce₂O₇ samples, that is (La_1-xSr_x)₂Ce₂O_7-x, were synthesized with sol -gel method. It is shown that (La_1-xSr_x)₂Ce₂O_7-x crystallize in pure defect-fluorite structure when the Sr-doping amount (x) is less than 0.1. With increasing of temperature, the thermal expansion coefficients (TECs) of (La_1-xSr_x)₂Ce₂O_7-x increase, and the thermal conductivities (TCs) decrease. At a certain temperature, the TECs of (La_1-xSr_x)₂Ce₂O_7-x increase with x increasing; and the TCs decrease when x changes from 0 to 0.075, then increase obviously when x≥0.075.