Effect of Carbon Nanotube Reinforcement on Electrical and Mechanical Properties of Copper Matrix Composites for Electrical Contact Applications

This study investigates the effect of multi-walled carbon nanotube (MWCNT) reinforcement on the electrical conductivity and mechanical properties of copper matrix composites fabricated for electrical contact applications in Nigerian power distribution equipment. Copper contacts in circuit breakers and switches are subject to combined mechanical and electrical stresses, and reinforcing copper with MWCNTs offers the prospect of improved mechanical strength without unacceptable sacrifice of electrical conductivity. MWCNT-Cu composites are fabricated by molecular-level mixing and spark plasma sintering (SPS) at 900 degrees Celsius at MWCNT contents of 0.5, 1.0, 2.0, and 3.0 volume percent. The MWCNTs are characterised by Raman spectroscopy and TEM before and after sintering to assess structural integrity. Composite characterisation includes relative density by Archimedes method, electrical conductivity by four-point probe, Vickers microhardness, tensile strength, and arc erosion resistance tested in a standardised contact-breaking simulation. SEM and TEM examination of fracture surfaces and interface regions assess MWCNT-matrix bonding. Results show that 1.0 volume percent MWCNT achieves the optimal balance: hardness increases by 42 percent and tensile strength by 38 percent above monolithic copper, while electrical conductivity is retained at 92 percent IACS. Arc erosion resistance improves at all MWCNT levels tested. Above 2.0 percent, MWCNT clustering reduces both strength and conductivity. Keywords: carbon nanotube, copper matrix composite, electrical contact, spark plasma sintering, electrical conductivity.