Effects of laser pretreatment process parameters on the properties of jet electrodeposited Ni-Co-YSZ composite coatings

Abstract This work investigates how laser pretreatment parameters—scanning speed, spacing, and scan number—govern the microstructure and performance of electrodeposited Ni-Co-YSZ composite coatings. SEM with 3D profiling, XRD, microhardness, and Corrosion resistance were employed. The composite coatings mainly exhibited an FCC phase structure under the investigated processing conditions, dominated by a close-packed (111) texture. Moderate pretreatment markedly improves surface leveling/densification and refines crystallites, giving the smallest average size. The parameter set ‘400 mm s −1 , 50 μm, five scans’ delivers the best overall properties: microhardness of 546.58 HV, corrosion current density of 6.309 μA cm −2 , and polarization resistance of 6.929 kΩ cm 2 . The study found that the improved hardness and corrosion resistance of the coating are the result of a synergistic effect of Hall-Petch strengthening and the dense passivation film formed by the (111) texture of the coating. Insufficient or excessive laser treatment can lead to surface growth or remelting-induced coarsening and more defects on the substrate, thereby affecting the subsequent electrodeposition of the composite coating and reducing the hardness and corrosion resistance of the coating.