氧离子导体La1.9Y0.1Mo2O9细晶粒陶瓷的制备和电学性质研究

采用溶胶凝胶法合成的La_1.9Y_0.1Mo₂O₉纳米晶粉体, 结合微波烧结技术制备出不同晶粒度的La_1.9Y_0.1Mo₂O₉块体样品. 利用X射线衍射仪(XRD)、高分辨透射显微镜(HRTEM)、场扫描显微镜(SEM)对粉体及陶瓷块体的物相、 形貌进行了表征, 利用交流阻抗谱仪测试了样品不同温度下的电导率. 实验结果表明, 掺Y的La_1.9Y_0.1Mo₂O₉能将高温立方β 相稳定到室温; 块体样品致密均匀, 平均晶粒度范围在60 nm–4 μm之间; 致密度高的样品表现出高的电导率, 其中900 ℃烧结样品的电导率600 ℃时高达0.026 S/cm, 比固相反应法制备的La_1.9Y_0.1Mo₂O₉样品高出约1倍. 总结认为样品的致密性对电导率影响较大, 是通过影响晶界电导率来影响总电导率的, 样品的晶粒度(在60 nm–4 μm范围内)对电导率的影响还不能确定. 关键词： 氧离子导体 1.9Y_0.1Mo₂O₉')" href="#">La_1.9Y_0.1Mo₂O₉ 细晶粒陶瓷 微波烧结

Synthesis and electrical property of oxide ionic conductor La1.9Y0.1Mo2O9 fine grain ceramic

A series of La_1.9Y_0.1Mo₂O₉ bulk samples of different grain sizes were made by microwave sintering the nanocrystalline powders prepared by sol-gel methods. Phases, microstructure, grain size of the powders and bulk samples were examined by using X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM); and the electrical properties of the bulk samples were studied by AC impedance spectroscopy. Experimental results show that the substituent Y can stabilize the cubic β phase to room temperature; the bulk samples are dense and uniform with an average grain size from 60 nm to 4 μm; the highly dense bulk samples show enhanced ionic conduction, e.g. the conductivity of the sample with relative density 99% is 0.026 S/cm at 600 ℃, which is two times higher than that of bulk samples prepared by solid-state reaction. It can be concluded that the effect of sample density on the electrical conductivity is mainly due to the grain boundary conductivity; and the effect of sample grain size (from 60 nm to 4 μm) on the electrical properties is not so significant.