Study of the preparation and properties of 0.5 vol% Ni-CNTs/Cu nanocomposites with magnetic alignment

Abstract

The 0.5 vol% Ni-CNTs/Cu nanocomposites with magnetic alignment were prepared by depositing nickel onto CNTs, flake ball milling (FBM), magnetic alignment treatment (MAT) and spark plasma sintering (SPS). The experiment results proved that the properties of the 0.5 vol% Ni-CNTs/Cu nanocomposites with magnetic alignment were anisotropic and the longitudinal properties (parallel to the axial direction of CNT) were the best with the tensile strength up to 292 MPa, the longitudinal elongation rate of about 34%, the longitudinal electronic conductivity of 93% IACS (3% higher than that of SPSed pure copper), and the longitudinal thermal conductivity of 339.8 W/mk (10% higher than that of SPSed pure copper). TEM analysis confirmed that the CNTs were aligned along the axial direction and dispersed uniformly in the Cu matrix. A small amount of Cu2O nanocrystals formed by in-situ reactions between hydroxylic or carboxylic groups of CNT and Cu atoms led to a strong CNT-Cu2O-Cu chemical bonded interface. The interface of the Ni-CNTs/Cu nanocomposites might be the strong CNT-Cu2O-Cu chemical bonding and the oxygen-mediated bonding (Cu-O-C/Ni-O-C). The strengthening mechanisms in the 0.5 vol% Ni-CNTs/Cu nanocomposites with magnetic alignment were ascribed to fiber strengthening through Cu/CNTs interfacial load transfer and strain hardening by CNT dislocation interaction.