Microstructure and Arc Erosion Performance of CuCr50Ni_X Coatings by Infrared-Blue Hybrid Laser Cladding

In this study, CuCr50Ni_X (X = 0, 0.1, 0.5, and 0.9 wt.%) coatings were successfully fabricated on a pure copper substrate via infrared-blue hybrid laser cladding. The effects of Ni addition on the microstructure, mechanical and electrical properties, and arc erosion resistance under 24 V/30 A conditions were systematically investigated. The results demonstrate that Ni refines the Cr phase and promotes the formation of a (Cr, Ni) solid solution and nanoscale Cr₇Ni₃ precipitates during non-equilibrium solidification. The coating with 0.5 wt.% Ni exhibits optimal comprehensive performance. It achieves a high microhardness of 174.2 HV_0.5, representing a 149% increase compared to the copper substrate (72 HV_0.5). Simultaneously, it maintains a good electrical conductivity of 29.8% IACS. Arc erosion morphology transforms from localized deep pits (CuCr50) to uniform, shallow characteristics (CuCr50Ni_0.5), accompanied by reduced cathode mass loss. This enhanced performance is attributed to the refined and dispersed Cr distribution, which facilitates dynamic arc root movement, together with improved phase boundary stability conferred by the (Cr, Ni) solid solution and Cr₇Ni₃ precipitates. This work provides a novel strategy for developing high-performance, long-life electrical contact components through surface alloying design and laser additive manufacturing.