Ambient electrical conductivity of carbon cathode materials for aluminum reduction cells

铝电解用碳阴极材料的室温导电性（英文）

The ambient electrical conductivity (AEC) of carbon cathode materials was investigated in respect to their open porosity, crystal structure and graphite content using hydrostatic method, four-probe technique and X-ray diffraction (XRD), respectively. The AEC is proportional to the specific conductivity (σ0) and the exponential of (1?ε) (ε is porosity) by a quasi-uniform formula based on the percolation theory. Theσ0 can reflect the intrinsic conductivity of the carbon cathodes free of pores, and it depends on the mean crystallite size parallel to the layer (002). The exponentn is dependent on the materials nature of the cathode aggregates, while an averaged value, 4.65, can practically work well with 5 types of cathode materials. The calculation ofσ0 can be extended to the graphitic cathodes containing different aggregates using the simple rule of mixture.

研究孔隙率、晶体结构及石墨含量对5种工业阴极材料室温导电性的影响规律。采用标准四探针法测定材料电导率,通过流体静力学法和XRD分析材料孔隙和晶体结构。结果表明:阴极室温电导率(σ)取决于其比电导率(σ_0)和孔隙率(ε),三者之间的关系可用基于逾渗理论的指数关系模型进行准近似描述。σ_0大小与孔隙无关,仅取决于材料的微晶尺寸和层间距,故可反映材料本征导电性;指数n与阴极骨料材质有关,但对所研究的5种阴极,可近似取平均值4.65。此外,石墨质阴极的比电导率(σ_0)可由混合物简单定则,根据其人造石墨含量计算而得。