Effect of annealing temperature on electrical and thermal property of cold-rolled multi-walled carbon nanotubes reinforced copper composites

Demanding for high thermal and electrical conductive copper-based composites for structural, electrical and thermal applications are being indispensable. In this work, a method is proposed to improve the electrical and thermal conductivity of multi-walled carbon nanotubes/copper (MWCNTs/Cu) composites by applying the annealing process. The effect of annealing temperatures on the electrical and thermal properties of MWCNTs/Cu composite containing 0.5 vol% MWCNTs prepared by conventional sintering followed by cold rolling was investigated. The experimental results indicated that as increasing annealing temperature, the electrical and thermal conductivity increased due to the recovery, the recrystallization and the grain growth of the Cu matrix. The electrical and thermal conductivity of cold rolled MWCNTs/Cu composite annealed at 500 degrees C are improved up to 9% and 19% respectively compared to the composite without annealing. The coefficient of thermal expansion (CTE) of the MWCNTs/Cu composite is 8% lower compared to the pure Cu attributed to uniform dispersed MWCNTs, low coefficient of thermal expansion of MWCNTs, good bonding between CNTs and the matrix.