Mechanical and electrical characterization of Cu-2 wt.% SWCNT nanocomposites synthesized by in situ reduction

Copper–2 wt.% single walled carbon nanotubes (SWCNT) nano composites have been synthesized by a chemical method of dissociation of copper nitrate containing CNTs, followed by reduction under a H2 atmosphere. Bulk nano-composite pellets were obtained by a pre-compactation under a uniaxial pressure of 60 MPa followed by isostatic pressure of 150 MPa and sintering under Ar atmosphere. Both X-ray diffraction and transmission electron microscopy (TEM) were used as characterization tools. The former confirmed the presence of pure metallic copper with carbon; and the later allowed for the observation of a good dispersion, and also for a proper adherence between Cu particles onto CNT. Powder copper particles were observed to be in the 50–300 nm range, while the bulk Cu–CNT grain size was observed to be in the 150 nm–3 μm range. The composite Cu–CNT presented less resistivity at low temperature (2 × 10−6 Ω cm at 83 K) compared with copper. Hardness measured by nanoindentation exhibited higher values for the composite than for copper (1.7 GPa vs. 1.2 GPa).

► We synthesized Cu–CNT nanocomposites by chemical route and thermomechanical processing.
► The composite presented good CNT's distribution and low grain size of Cu grains.
► Heterogeneous Cu grain size increases during the stages of consolidation and sintering.
► Nanotubes are successful in transferring a hardening effect to the composite.
► The composite displays higher conductivity compared to pure copper.