石墨/陶瓷复合导电材料的制备及性能

Preparation and properties of graphite/ceramic conductive composites

  • 摘要: 为了研究片状石墨的掺杂量和取向排列对石墨/陶瓷复合材料结构和性能的影响,以长石、透辉石、石英等作为陶瓷基体并掺杂石墨,经湿混、干燥、干压成型、快速烧结等工艺制备了石墨/陶瓷复合导电材料。用精密伏安表精确测定了材料垂直和平行于成型压力方向的电阻,用XRD、SEM分析了试样的物相组成和断面形貌。实验结果表明:在烧结过程中石墨与陶瓷基体不发生化学反应,未发现有新相生成;片状石墨在复合材料中具有定向排列的特征,即片状石墨的c轴平行于成型压力方向;石墨/陶瓷复合导电材料的电阻率具有明显的各向异性;随着石墨掺量的增加,复合导电材料的电阻率随石墨掺量的增加而急剧减小;但是,当石墨掺量超过15 wt%时,复合材料电阻率的变化趋于平缓。

     

    Abstract: In order to investigate the effects of the plate graphite content and its preferred orientation on the structure and property of graphite/ceramic composites,graphite/ceramic conductive composites were prepared from the ceramic matrix (albite,diopside,quartz) and graphite by wet-mixing,drying,granulating,and rapid sintering processes. The electric resistance along directions perpendicular and parallel to the molding pressure was accurately measured. The grain phases and the fracture surface micrograph were analyzed with XRD and SEM. The results show that the ceramic matrix reacts hardly with the graphite in the sintering process and no new phase is found. The plate graphite of the graphite/ceramic conductive composites is oriented,and the c-axis of graphite inclines to be parallel to the direction of the molding pressure. The resistivity of graphite/ceramic conductive composites is anisotropic. With the increase of the graphite content,the resistivity of composites rapidly decreases. However,it decreases very slowly when the graphite content exceeds 15 wt%.

     

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