Process optimization of Cu-Mo coatings via ultra-high-speed laser cladding and Box-Behnken design enhanced wear and corrosion resistance for marine applications

This study presents an innovative approach to overcome Cu-based materials’ inherent limitations (inadequate wear/corrosion resistance) and the alloying challenge of the immiscible Cu-Mo system. Using ultra-high-speed laser cladding, we fabricated Cu-Mo cladding layer with optimized parameters via Box-Behnken Design (BBD) response surface methodology, with three key variables: laser power (2500–4000 W), scanning speed (100–200 mm/s), and powder feeding rate (1.5–2.5 r/min). Comprehensive characterization techniques including X‑ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy‑dispersive X‑ray spectroscopy (EDS), microhardness testing, and electrochemical analysis, complemented by laser power single-factor experiments, elucidated the underlying mechanism of laser power-regulated Mo particle dissolution-dispersion and its correlation with the microstructure-performance of Cu-Mo cladding layer. Results showed scanning speed and powder feeding rate were predominant in controlling cladding thickness. At the optimal 3000 W, Mo particles uniformly dispersed in the Cu matrix, achieving 0.99% porosity, 71.0 HV microhardness, 1.451 × 10⁻⁵ mm³·N⁻¹·m⁻¹ wear rate, and superior corrosion resistance (7.36 µA/cm² in 3.5 wt% NaCl). The optimized parameters ( P  = 3000 W, V = 150 mm/s, F = 2 r/min) establish a technical foundation for immiscible alloy system surface strengthening.