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

Abstract

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.

Electrical Characterization of Carbon Nanotube Reinforced Silver and Copper Composites for Switching Contacts

“…Softer composites were to be expected on account of the sintering process at relatively high temperatures and prolonged holding times-particularly in the silver MMC due to the re-pressing process. As reported by Garcia et al [49], a reduction in the sintering temperature of 200 °C yields much harder composites as a consequence of shorter coarsening times for microstructural processes to occur (i.e., recovery and grain growth). Consequently, a trade-off must be made between better mechanical performance and proper densification of our composite samples.…”

A 3D-printed CuNi alloy catalyst with a triply periodic minimal surface for the reverse water-gas shift reaction

“…Compared to standard copper (PDF # 04-0836) and nickel (PDF # 04-0850), the shift in the XRD peaks of the as-printed catalyst suggested the formation of CuNi alloys. 37,38…”

“…Compared to standard copper (PDF # 04-0836) and nickel (PDF # 04-0850), the shi in the XRD peaks of the as-printed catalyst suggested the formation of CuNi alloys. 37,38 Moreover, X-ray photoelectron spectroscopy (XPS) analysis of the as-printed catalyst further indicated the co-existence of Cu and Ni (Fig. S4a †).…”