Parameters Optimization of Pulse Electrodeposited Ni-Cu Coatings on Aluminum Alloy Based on Combination of Improved Artificial Hummingbird Algorithm and CRITIC-TOPSIS Method

• • Current density elevation refines grain structure, increasing hardness and corrosion resistance, but exceeding 3.87 A/dm² degrades thermal conductivity; the optimized 3.87 A/dm² balances these competing properties, yielding a thermal conductivity of 11.11 W/(m·K) and corrosion current density of 1.21 μA/cm², critical for heat exchanger applications where thermal management cannot be compromised. • • The MOAHA algorithm with Fuch chaotic mapping and improved crowding distance identified a duty cycle of 75% and frequency of 262 Hz as optimal, producing a wear rate of 1.092×10⁻⁵ mm³/(N·m) and microhardness of 273.70 HV0.05; these values represent a 20–30% improvement over unoptimized coatings, directly extending component service life in abrasive environments. • • The YH coating's performance enhancement originates from a dense, fine-grained microstructure rather than compositional changes, as confirmed by XRD and microstructural analysis; this eliminates the need for costly alloying elements, enabling cost-effective scale-up using standard pulse electrodeposition equipment. • • The CRITIC-TOPSIS framework objectively weighted performance indices by evaluating variability and information redundancy, removing subjective bias in parameter selection; this reproducible decision-making protocol can be adapted to other multi-objective electrodeposition systems, reducing trial-and-error iterations by approximately 40% compared to conventional orthogonal optimization.