Comparison of the effects of microwave and spark plasma sintering on the electrical, thermal, and mechanical properties of Cu-LaB6 nanocomposites

Abstract

The effects of lanthanum hexaboride (LaB6) nano-particles on the electrical, thermal, and mechanical properties of copper-based nanocomposites (Cu-LaB6) produced using microwave sintering (MS) and spark plasma sintering (SPS) processes were investigated in this study. Nano LaB6 particles reduced the electrical conductivity of Cu matrix nanocomposites produced via MS and SPS by 20% and 13%, respectively. Cu-LaB6 nanocomposites had lower thermal conductivity than unreinforced Cu. The electrical and thermal conductivities of the Cu-LaB6 nanocomposite produced by the SPS process were higher than those of the Cu-LaB6 nanocomposite produced by the MS process. An equation that takes particle volume ratio and porosity into account was developed to predict the thermal conductivity of nanocomposites from their electrical conductivity. The calculated thermal conductivity values for Cu-LaB6 nanocomposites were very close to the experimental results. Cu-LaB6 nanocomposites had much higher hardness and compressive strength by 49% and 38%, respectively, compared to those of unreinforced Cu. The hardness and compressive strength of the Cu-LaB6 nanocomposite produced by SPS were higher than those of the Cu-LaB6 nanocomposite manufactured via MS. Although nano LaB6 reinforcement particles reduced the electrical and thermal conductivities of Cu, Cu-LaB6 nanocomposite having high hardness and compressive strength were produced by combining the positive influences of nano LaB6 reinforcement particles and the SPS process.