Effect of the reinforcement phase on the electrical and mechanical properties of Cu–SWCNTs nanocomposites

Abstract

In this research a pre-treatment of single-walled carbon nanotubes (SWCNTs) was performed to obtain Cu–SWCNTs composites by powder metallurgy technique. The SWCNTs were subjected to a chemical functionalization in acidic medium followed by a copper coating to improve their incorporation into the metal matrix. The results revealed a considerable inclusion of carboxyl, carbonyl and hydroxyl groups in the nanotubes, maintaining their structural integrity which was demonstrated by characterization using X-ray photoelectronic spectroscopy (XPS), scanning electron microscopy (SEM) and Raman spectroscopy techniques. The electroless process used allowed a complete reduction of copper sulfate to a metallic copper obtaining a suitable and homogeneous carbon nanotubes incorporation into the copper matrix. Microhardness measurements of the Cu–0.01 % SWCNT composite presented an improvement of 13 % compared with pure copper. Furthermore, this composite showed the best tribological properties obtaining a wear rate of 2.1 × 10−4 mm3/Nm, 18 % better than Cu, which was associated with the improved dispersion of the SWCNTs bundles into the matrix, and with a lower amount of surface defects. The maximum electrical conductivity obtained was 96 % IACS in the samples with the least amount of reinforcement phase which confirms their homogeneity into the copper matrix.