Microstructure and electrical conductivity of high volume Al2O3-reinforced copper matrix composites produced by plasma spray

A mixture of Cu/α-Al2O3 (30:70 in vol.%) feedstock powder was plasma-sprayed onto a graphite substrate in order to investigate the electrical conductivity and microstructure of the deposits. As input power increased, the amount of phase transformed γ-Al2O3 and the volume fraction of Al2O3 in the plasma-sprayed composites increased, while the electrical conductivity decreased. Cuprite (Cu2O) was also found in the deposits. The electrical conductivities of the plasma-sprayed Cu/Al2O3 composites were compared to those of the different predictive models. It was revealed that the two-phase self-consistent predictive model had the closest agreement with the measured values.