SiO_2添加物对CaCu_3Ti_4O_(12)陶瓷的微观结构与介电性能的影响

采用传统固相反应法制备了不同SiO_2掺量的CaCu_3Ti_4O_(12)(CCTO) 陶瓷材料,并研究了SiO_2含量对CCTO陶瓷物相结构、微观形貌及介电性能的影响.结果表明:高温烧结时,SiO_2不会与CCTO发生固相反应,而作为第二相物质存在于CCTO陶瓷的晶界,并对CCTO陶瓷的微观结构产生不同程度的影响.CCTO陶瓷的介电常数和介电损耗随SiO_2含量的增多而相应减小.阻抗分析表明,CCTO陶瓷的晶粒电阻随SiO_2的掺入略有改变,而晶界电阻则随SiO_2的掺入而显著增大.分析认为,晶界电阻的增大是导致CCTO陶瓷介电损耗降低的主要原因.

Influence of SiO_2 Additives on the Microstructure and Dielectric Properties of CaCu_3Ti_4O_(12) Ceramics

CaCu_3Ti_4O_(12) (CCTO) ceramics with the addition of SiO_2 were fabricated by the conventional solid-state reaction method. The phase structure, microstructure and the dielectric properties of the CCTO ceramics with different weight percentages of SiO_2 were investigated. There was no solid-state reaction between CCTO and SiO_2 at the sintering temperature, and the SiO_2 additives were observed to be present at the CCTO grain boundaries. It was found that the addition of SiO_2 influenced the microstructure and dielectric properties of the CCTO ceramics. The dielectric constant and loss tangent decreased with the increasing content of SiO_2. Impedance spectroscopy showed that the grain boundary resistance increased due to the addition of SiO_2 to CCTO, which should be main reason for the decrease in the loss tangent of the CCTO ceramics.