A zero-thermal-expansion composite with enhanced thermal and electrical conductivities resulting from 3D interpenetrating copper network

Abstract

Zero-thermal-expansion (ZTE) materials are crucial to the fields where the temperature-induced dimension change should be avoided. Here we report a new ZTE composite made of copper foam, negative-thermal-expansion (ZSM) and copper powders. Without changing the volume ratio of ZSM (32 vol%) which ensures that all composites exhibit ZTE around room temperature, we can significantly improve the thermal conductivity (TC) and electrical conductivity (EC) of the composites by increasing the pre-compressing degree of the copper foam. For example, the TC and EC along the direction parallel to the pressurized plane for the composite with 75% copper foam pre-compression reach 83.4 Wm−1K−1 and 9.43 × 106 Ω−1m−1, which are 46% and 71.9% larger than that of the reference composite without copper foam. The improved conductivity is attributable to the oriented three-dimensional interpenetrating metal network derived from copper foam. This work provides an effective way for improving the thermal and electrical conductivities of copper matrix composites.