石墨热压还原Cu/Cu_(2)O金属陶瓷电导逾渗行为与微观结构分形表征EI北大核心CSCD

采用石墨热压还原法制备Cu/Cu_(2)O金属陶瓷复合材料,并测试不同导通相(Cu)体积含量Cu/Cu_(2)O金属陶瓷复合材料的直流电导率。为了实现对导通相形状、大小和分布状态的定量表征,通过对复合材料微观结构图像的二值化处理进行导通相分形维数计算,结合Cu/Cu_(2)O金属陶瓷复合材料的电逾渗行为,分析复合材料微观结构与电性能之间的对应关系。结果表明:随着导通相体积分数的增加,逾渗无限团簇和逾渗骨架的总量随之增大,但逾渗骨架密度在逾渗阈值附近波动。此外,Cu/Cu_(2)O金属陶瓷复合材料垂直热压方向与平行热压方向的分形维数相差约0.1。分形计算为定量表征导体/绝缘体双相复合材料中导通相的微观结构提供了一种计算方法,有助于对第二相随机分布的复合材料实现微观结构定量表征。

Electrical percolation behavior and microstructure fractal characterization of graphite reduced hot-pressing Cu/Cu2O cermet composites

Cu/Cu₂O cermet composites were prepared with hot pressing graphite reduction methods.The DC electrical conductivity of Cu/Cu₂O cermets,with various volume contents and random distribution status of the conducting phase was tested.To quantitatively characterize the shape,size,and distribution status of the conducting phase,the fractal dimensions of the conducting phase(Cu)were calculated through the binarized image analysis.The percolation behavior was analyzed,and the relationship between microstructure and electrical properties was studied.The results show that the quantities of the percolation infinite cluster and backbone increase with the increasing volume fraction of the conducting phase,but the backbone density fluctuates near the percolation threshold.Furthermore,the difference of fractal dimension between Cu/Cu₂O cermet composites perpendicular to hot pressing direction and the parallel to hot pressing direction is about 0.1.An approach is provided to quantitatively characterize the microstructure of the conducting phase in dual-phase conductor/insulator composites,which is beneficial to predict the properties of composites with a randomly distributed second phase.