Ce_(1-x)Gd_xO_(2-x/2)的溶胶-凝胶法合成及其性质

Sol-gel Synthesis and Properties of Ce_(1-x)Gd_xO_(2-x/2) Solid Solutions

利用溶胶 -凝胶法合成了 Ce1-x Gdx O2 -x/ 2 ( x=0 .1～ 0 .6)系列固体电解质 ,系统地研究了其结构、热膨胀系数和导电性 .XRD结果表明 ,1 60℃即完全形成立方萤石结构 .由于溶胶 -凝胶法合成的物质粒度均匀 ,颗粒小 ,故在较低温度 ( 1 30 0℃ )时即可形成高致密样品 ,此温度明显低于传统的高温固相法烧结温度( 1 60 0～ 1 65 0℃ ) .高温 X射线衍射测得 Ce0 .8Gd0 .2 O1.9的热膨胀系数为 8.1 2 5× 1 0 -6K-1.阻抗谱表明 ,溶胶 -凝胶法合成可减少或消除固体电解质的晶界电阻 ,60 0℃时 Ce0 .8Gd0 .2 O1.9的电导率为 5 .2 6× 1 0 -3S/cm,活化能 Ea=0 .82 e V.

A series of solid electrolytes Ce 1- x Gd x O 2- x /2 ( x =0~0.6) was prepared by sol gel method. The structure, thermal expansion coefficient and electrical properties of the solid solutions were systematically studied. XRD data showed that a complete cubic fluorite structure was formed at 160 ℃. The purity of the product prepared by the sol gel method is higher, the grain size is uniformly smaller. They were easily sintered into highly dense ceramic pellets at 1 300 ℃. The sintering temperature was significantly lower than that by traditionally high temperature solid phase reaction method. The thermal expansion coefficient of Ce 0.8 Gd 0.2 O 1.9 , determined from high temperature XRD data, is 8.125×10 -6 K -1 . Impedance spectra analyses showed that the grain boundary resistance of the solid electrolyte prepared by sol gel method was reduced or even eliminated. The conductivity of Ce 0.8 Gd 0.2 O 1.9 is 5.26×10 -3 S/cm at 600 ℃. The activation energy ( E a) is 0.82 eV.