碳化硅含量对炭/陶复合导电材料组织和性能的影响

Effects of SiC Contents on Microstructures and Properties of Carbon / Ceramic Conductive Composites

以长石、透辉石、石英等为陶瓷基料掺杂石墨、碳化硅,经湿混、干燥、干压成型、快速烧结等工艺制备了复合导电材料。测定了试样的气孔率、吸水率、烧成收缩率、烧失率以及抗弯强度,并分别用XRD和SEM分析晶相组成和断面显微结构,研究了碳化硅含量对复合材料电阻率的影响。实验结果表明:碳化硅的含量由1%增大到3%时,炭/陶复合导电材料的显微结构无显著变化,气孔率增大,烧成线收缩率降低,弯曲强度下降,电阻率变大;碳化硅含量由3%增大到9%时,炭/陶复合导电材料的陶瓷颗粒界面上形成一层白色碳化硅颗粒层,气孔率减小,弯曲强度增大,电阻率急剧降低;与碳化硅含量为1%的炭/陶复合导电材料相比,碳化硅含量增大到9%时,炭/陶复合导电材料孔隙率减小,弯曲强度增大,电阻率降低。

Graphite-ceramic conductive composites were prepared from the ceramic matrix （ albit , diopside , quartz ）, graphite and SiC with wet-mixing , drying , granulating , and rapid sintering processes.The porosity , water absorption , shrinkage rate , weight loss and flexural strength were measured.The grain phases and the fracture surface micrograph were analyzed with XRD and SEM. Influences of SiC contents on the resistivity of composites were studied on.The results show that the flexural strength and conductive properties of composites are decreased when SiC content increases from 1%to 3% , whereas they are improved obviously when the SiC content increases from 3% to 9%.And there is no obviously change in the surface of ceramic particles when the SiC contents ranged from 1%to 3% , while more and more white SiC particles are adhere to the ceramic surface in the conductive composites with the SiC contents ranging from 3%to 9%.