Novel Cu–Ni/SiC metal contacts with improved mechanical and electrochemical properties

Abstract

Silver-based materials are the current benchmark for electrical contacts in circuit breakers due to their high conductivity and corrosion resistance. However, their high cost and limited global availability drive the development of sustainable alternatives. In this context, copper-based composites are attractive because of their lower cost and good conductivity, in addition to the copper capacity to be recycled in almost infinite cycles, but their long-term performance is limited by corrosion processes and wear properties for low-voltage circuit breakers applications. The novelty of this investigation relies on a systematic approach for analyzing the chemical composition and processing of copper–nickel/silicon carbide (Cu–Ni/SiC) composites to establish how particle size and sintering atmosphere can be improved to simultaneously increase electrical and mechanical performance under demanding industrial operating conditions. In this study, Cu-based composites reinforced with 10 wt% SiC and alloyed with up to 3 wt% Ni were produced by powder metallurgy under different argon flow rates (0.9 and 2.5 L min-1) and using two Ni particle sizes (10 μm and 110 μm). Comprehensive characterization included hardness, density, electrical conductivity, wear resistance, and electrochemical testing. The optimal condition (1.5 wt% Ni with 10 μm particles at low argon flow) achieved a surface hardness of 68 HR30T, relative density of 95 %, and electrical conductivity of ~30 IACS%. Specific wear rate improved down to 5.5 × 10���� 5 mm3/N⋅m, while corrosion rates remained below 800 mpy. These results show that fine Ni particles at 1.5 wt% under low argon flow uniquely enable a balance between hardness, conductivity, and corrosion resistance, outperforming composites using larger Ni particles. This cost-effective and durable Cu–Ni/SiC metal contacts offer a promising alternative to Ag-based materials in low-voltage circuit breakers applications.