Influence of Surface Roughness on Reflectivity and Laser Ablation Resistance of Cold-Sprayed Copper Coatings

Abstract Copper is widely used for its excellent thermal conductivity and high reflectivity, yet its response to laser irradiation is highly dependent on surface condition. While roughening bulk copper is known to enhance laser absorption, no data exists on cold-sprayed copper coatings. This study compares two surface conditions of cold-sprayed pure copper coatings, as-deposited and mirror-polished. Surface roughness, optical reflectivity, and response to a continuous-wave fiber laser at 1 kW/cm 2 for 10 s were evaluated. Results reveal that the rough surface reflects less laser energy and experiences ablation than the polished one. These findings highlight the critical role of surface finish in laser resistance and offer guidance for optimizing copper coatings for high-energy laser applications.