SiCw/Si3N4复合陶瓷的制备及介电性能的研究

Preparition and Dielectric properties of SiCw/Si3N4 composite ceramic

摘要:

采用凝胶注模成型工艺制备了SiCw/Si₃N₄复合陶瓷,扫描电镜图(SEM)可以看出随热处理温度升高,碳化硅晶须的长径比逐渐缩短；随烧结温度升高，复合陶瓷开孔率降低，密度随晶须含量的增加而增加。研究表明,SiCw/Si₃N₄复合陶瓷的介电常数实部和虚部随碳化硅晶须含量的增加而升高,当烧结温度为1600℃,晶须含量从5%增加到15%时,8GHz时介电常数实部从13.4增加到22.8,虚部从0.67增加到4.86；当烧结温度为1750℃时,8GHz时实部从9.2增加到21.7,虚部从0.51增加到3.02。反射率曲线可以看出,烧结温度为1750℃比1600℃时反射衰减随SiCw含量的增加向低频移动的更快,频宽更宽。

Abstract:

Gelcasting was employed to fabricate Si₃N₄/SiC whisker (SiCw) composite ceramics. SEM showed the effects of heat-treatment temperature on the length-to-diameter ratio of the whiskers. The open porosity of composite ceramics declined and density increased as the whisker content raised when the sintering temperature increased. Study also showed that both the real (ε￠) and imaginary (ε2) permittivity of Si₃N₄/SiC whisker (SiCw) composite ceramics decreased with increasing frequency and increased as the whisker content raised in the frequency range of 8.2~12.4GHz. As the whisker content increased from 5 wt% to 15