烧结温度对La0.9Sr0.1FeO3热电性能的影响

利用传统的固相反应分别在1250℃，1300℃，1350℃.烧结条件下制备出钙钛矿结构的La_0.9Sr_0.1FeO₃陶瓷样品.样品的XRD粉末衍射结果显示不同烧结温度的La_0.9Sr_0.1FeO₃陶瓷样品都是单相的正交结构，同时晶胞体积随着烧结温度的升高而减小.从样品的SEM结果看出，随着烧结温度的升高，晶粒逐渐变大，并且晶粒间的空隙逐渐减小，样品更加致密.在室温到800℃的 关键词： 铁酸镧陶瓷 热电性能 烧结温度

Influence of sintering temperature on thermoelectric properties of La0.9Sr0.1FeO3 ceramics

Perovskite La_0.9Sr_0.1FeO₃ ceramics have been synthesized at 1250℃，1300℃ and 1350℃ by the conventional solid-state reaction technique. From their crystal structures determined by powder X-ray diffraction，we found that the lattice volume decreases with increasing sintering temperature. The scanning electronic microscope (SEM) images of surface microstructures of the samples show that the average grain size increases with increasing sintering temperature. The electrical resistivity and Seebeck coefficient have been measured between room temperature and 800℃. At low temperatures，the electrical resistivity shows a semiconductivity-like behavior. With further increasing of temperature，the electrical resistivity slightly increases. An adiabatic hopping conduction mechanism of small-polarons is suggested from the temperature dependence of the electrical resistivity，which has different activation energies at low and high temperatures. The Seebeck coefficient rapidly decreases with increasing temperature，and reaches a saturation value about 600℃. With further increasing of temperature，the Seebeck coefficient slightly increases. With the increase of sintering temperature，the electrical resistivity decreases，while the Seebeck coefficient increases. Therefore，the power factor increases with increasing sintering temperature. The highest power factor of 90 μW/K²m was obtained at 727℃ for sample sintered at 1350℃.