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

Abstract

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.

Keywords

• dual-phase composite
• percolation
• fractal
• electrical conductivity
• backbone density
• hot-pressing