Powder‐Metallurgical Fabrication and Electrical Contact Resistance Characterization of Copper–Nickel Composites Reinforced by Multiwalled Carbon Nanotubes

This article studies copper (Cu)-based composites alloyed with nickel (Ni) and reinforced with carbon nanotubes (CNTs) fabricated via powder metallurgy under pressureless sintering methodology and vacuum. Different compositions of matrices containing 0, 3, and 30 wt% Ni are compared after sintering at 550 and 750 °C. The formation of phases for the different compositions is analyzed by high-temperature X-ray diffraction (HT-XRD) in the solid-state range up to 800 °C, in which reduction of oxides along with the sintering can be identified. Subsequently, the matrices are reinforced with pristine multiwalled CNT (MWCNT) in contents of 0, 0.5, and 1.0 wt% prior to sintering, whose dispersion is influenced by the powder's morphology. A custom-made electrical contact resistance (ECR) setup is used to investigate the electrical behavior of the sintered samples, which, particularly, allows the identification of improvements in electrical conduction of samples containing 0.5 wt% CNT and 3 wt% Ni. A reduction in chemical incompatibilities between Cu and CNT can be attributed to the presence of Ni in solid solution