Mechanical and Conductive Properties of Cu Matrix Composites Reinforced by Oriented Carbon Nanotubes with Different Coatings

Abstract

Because of the dilemma that the current industrial Cu enhancement methods lead to a significant decline in conductivity and ductility, Cu matrix composites reinforced by oriented multi-walled carbon nanotubes (MWCNTs) were prepared through sintering, hot extrusion, and cold drawing. Before sintering, Ni, Cu, and Ni&Cu coatings were electroless plated on MWCNTs as the intermediate transition layer, and then they were mixed with Cu powder through a nitrogen bubbling assisted ultrasonic process. By analyzing the composition, microstructure, and formation mechanism of the interface between MWCNTs and the matrix, the influence and mechanism of the interface on the mechanical properties, conductivity, and ductility of the composites were explored. The results indicated that MWCNTs maintained a highly dispersed and highly consistent orientation in the Cu matrix. The coating on Ni@CNT was the densest, continuous, and complete. The Ni@CNTs/Cu composite had the greatest effect, while the Cu composite reinforced by MWCNT without coating had the smallest reduction in elongation and conductivity. The comprehensive performance of the Cu@CNTs/Cu composite was the most balanced, with an ultimate tensile strength that reached 373 MPa, while the ductility and conductivity were not excessively reduced. The axial electrical and thermal conductivity were 79.9 IACS % (International Annealed Copper Standard) and 376 W/mK, respectively.

Life and failure of oriented carbon nanotubes composite electrode for resistance spot welding

“…Cu@MWCNTs/Cu composite electrodes prepared by our group according to a series of processes such as chemical plating, powder mixing, sintering, hot extrusion, cold drawing and reverse extrusion [7,8], as shown in Figure 1. In the prepared composite electrode, the MWCNTs coated with Cu remained straight and long, and the MWCNTs/Cu interface was tightly bonded.…”

“…When the galvanized sheet is spot welded, the harsh working environment puts forward higher requirements for the electrode materials, that is, the mechanical properties, electrical/thermal conductivity and wear resistance should be superior. Our research group has designed and prepared MWCNTs/Cu composites for this requirement [7,8]. We consider that the physical basis of the composite effect is derived from the difference in properties between the metal matrix and the reinforcements.…”

“…These make CNTs an ideal enhancements that can significantly improve the properties of the matrix, and do not damage its conductivity of the composites. In MWCNTs reinforced Cu matrix (Cu@MWCNTs/Cu) composites prepared by our group [7,8], Cu-coated MWCNTs remain straight and long, and MWCNTs/Cu interface was tightly bonded. MWCNTs are uniformly dispersed in Cu matrix and arranged along the flow direction of working electric/force.…”

Electrochemical Behavior of Cu-MWCNT Nanocomposites Manufactured by Powder Technology

“…Rod-shaped reinforcements such as CNTs, which have short inter-reinforcement spacing, more effectively strengthen the matrix compared to spherical reinforcements. Additionally, CNTs display extraordinary mechanical properties as they have a very high Young's modulus of 2 TPa and a tensile strength higher than one hundred folds the strength of steel [14,15]. In addition to their extraordinary mechanical properties, CNTs have superior electrical and thermal properties and favorable chemical stability.…”