Strengthening of copper matrix composites by nickel-coated single-walled carbon nanotube reinforcements

Mechanical, electrical and thermal properties of nickel-coated single-walled carbon nanotube (SWNT) reinforced copper matrix composites were investigated. The composites were fabricated by means of a powder metallurgy process, which consists of mixing nickel-coated carbon nanotubes with copper powders followed by hot-pressing. A homogeneous mixture could be obtained by the mechanical mixing process due to the similar density of nickel and copper. A high temperature displacement rate tester and a ball-on-disk device were employed to evaluate mechanical and tribological properties. Also, a four-point probe technique and a laser flash method were used to obtain electrical resistance and thermal conductivity. The mechanical and tribological properties of the copper matrix composites significantly improved by the incorporation of nickel-coated SWNT reinforcements. However, electrical resistance and thermal conductivity of the nickel-coated SWNT reinforced copper matrix composites were similar to those of the sintered nickel-copper specimens with the equivalent composition. (C) 2008 Elsevier B.V. All rights reserved.