Bi_(2)Cu_(0.1–x)WxV_(0.9)O_(5.35–δ)的结构和氧离子导电性能

STRUCTURE AND OXYGEN IONIC CONDUCTIVITY OF Bi_2Cu(0.1–x)WxV_(0.9)O_(5.35–δ)

用乙二胺四乙酸(ethylenediamine tetraacetic acid,EDTA)–柠檬酸溶胶–凝胶法制备出具有单一Aurivillius结构的Bi2Cu0.1–xWxV0.9O5.35–δ(x=0,0.02,0.05,0.08)陶瓷。用X射线衍射、扫描电镜、差热分析、交流阻抗谱法等方法研究了陶瓷样品的晶体结构、显微结构和氧离子导电性能。结果表明:钨离子含量对陶瓷样品的晶体结构有明显的影响,但对显微结构的影响不显著。在室温下,x≤0.05时,陶瓷样品为四方结构,x=0.08的陶瓷样品转变为正交结构。钨离子含量对室温下为四方结构的陶瓷样品(x≤0.05)的γ’–γ相变动力学过程有显著影响。x≤0.05时,增加钨离子的含量可以提高陶瓷样品的氧离子电导率,x=0.05的陶瓷样品在600℃时的氧离子电导率达到0.14S/cm。

Copper and tungsten substituted bismuth vanadate Bi2Cu0.1-xWxV0.9O5.35-σ（x=0, 0.02, 0.05, 0.08） ceramics with a pure Aurivillius phase were produced by a sol-gel method using ethylenediamine tetraacetic acid （EDTA） and citric acid as mixed complexing agents. The crystal structure, microstructure and oxygen ionic conductivity of the ceramic specimens were examined by X-ray diffraction, scanning electron microscope, differential scanning calorimetry, and alternating current （AC） impedance spectroscopy, respectively. The results reveal that the crystal structure of the specimens highly depends on the content of tungsten, while no remarkable effect of the tungsten content on the microstructure was found. At room temperature, the ceramic specimens with x≤0.05 presented a tetragonal symmetry and that with x=0.08 show an orthorhombic symmetry. A considerable influence of the tungsten content on the dynamics of y＇-y phase transition in the ceramic specimens with x≤0.05 at room temperature was observed. At an identical measuring temperature, the oxygen ionic conductivity tends to increase with increasing tungsten content for the ceramic speci-mens with x≤0.05, and the specimen with x=0.05 providing a superior oxygen ionic conductivity of 0.14 S/cm at 600℃.