钆掺杂氧化铈纳米陶瓷的中温介电行为

Mid-temperature Dielectric Behavior of CeO2 Nano-ceramics Doped with Gd

采用溶胶凝胶法制备10mol%的Gd离子掺杂CeO2(GDC10)纳米陶瓷,并通过一系列测试方法表征了焙烧粉体的物相、形貌、晶粒尺寸及比表面积,测试了样品的介电参数,研究了其在温度为300-900 K,频率为1×10^2-1×10^6 Hz的环境下的介电性能和介电弛豫的形成机制。结果表明,Gd离子可以掺杂进CeO2晶格中,产生大量的游离氧空位;样品的介电常数在中低温区发生抛物线式的增高现象;而良好的湿敏特性在一定程度上会抑制介电弛豫的形成和介电常数的升高。

1Omol%Gd ion-doped CeO2(GDC 10)nano-ceramics were prepared from powder made with sol-gel method.Phase composition,morphology,grain size and specific surface area of the calcined powder were characterized.Dielectric parameters of the ceramic samples were measured by using a series of testing methods.The dielectric properties and the mechanism of dielectric relaxation of the samples over the temperature range of 300-900 K and the frequency range of 1 x102-1x106 Hz were studied.It was found that Gd ions can be well doped into the lattice of CeO2,resulting in a large number of oxygen vacancies.A parabolic increase in dielectric constant of the GDC 10 sample was observed in the middle and low temperature regions.It is the humidity sensitive behavior that restrained the formation of dielectric relaxation and result in the increase in dielectric constant to a considerable degree.