MgO-CeO2二元系复相陶瓷的微波介电性能研究

采用传统固相法制备了xMgO-yCeO2[摩尔百分比(mol％):x:y=1:1、1:2和2:1]二元系微波介质陶瓷,并研究了该体系的相组成、烧结性能和微波介电性能之间的影响关系.X射线衍射(XRD)结果表明,当烧结温度为1520～1680℃时,所研究组分范围内MgO-CeO2二元系并未形成固溶体,均为MgO与CeO2两相共存态;电子扫描显微镜带能谱仪(SEM-EDS)分析结果也进一步证实了这一现象的正确性.这说明,在MgO-CeO2二元体系内,各组分反应的吉布斯标准自由能较高.此外,由矢量网络分析仪测试所得的微波介电性能可知,随着烧结温度的增加,MgO-CeO2、2MgO-CeO2和MgO-2CeO2复相陶瓷的εr受温度的影响程度较小,而Q×f值(f=6.6～7.7 GHz)则呈先增后减趋势;其中,在1600℃烧结4 h时,该系列样品的τf值均处于(-59～-62)×10-6/℃范围内.此外,以上分析结果也为MgO-CeO2二元系相图的成分裁剪范围和构建提供了一定的实验依据.

Microwave Dilelectric Properties of MgO-CeO2 Multiphase Ceramic Systems

xMgO-yCeO2[molar percentage (mol％): x:y =1 :1, 1 :2 and 2 :1] binary microwave dielectric ceramic systems were prepared by the conventional solid-state reaction process , and the phase compositions , sintering properties and microwave dielectric of the sintered samples were investigated .The X-Ray Diffraction ( XRD ) results show that the MgO-CeO2 systems within the scope of research components can not form solid solution phases , while the two-phase coexistence , CeO2 and MgO, was detected in the range of sintering temperature from 1520℃to 1680℃.Additionally , the analysis results of the Scanning Electron Microscope with Energy Dispersive Spectrometer ( SEM-EDS ) had also further confirm the validity of this phenomenon .It also means that the gibbs standard free energy of these relevant compound formations in MgO-CeO2 systems are relatively high .In addition, the microwave dilelectric properties measured by a vector network analyzer illustrate that the εr of the MgO-CeO2 , 2MgO-CeO2 and MgO-2CeO2 multiphase ceramics have only a little influence on sintering temperature , while the Q ×f ( f=6.6-7.7 GHz) values firstly increase and then decrease with an increase in sintering temperatures.Wherein, the τf values in these ceramic systems sintered at 1600 ℃ for 4 h are in the range of ( -59--62 ) ×10 -6/℃.Moreover, some important experimental bases are provided for expanding the range of composition tailoring and designing binary phase diagram for MgO-CeO2 systems.