Wettability, Microhardness, Wear and Corrosion Resistance of Ni–Co–P–BN(h)–Al2O3 Binary Nanocomposite Coatings Surface with Varying Long-Pulse Laser Parameters

In this study, Ni–Co–P–BN(h)–Al2O3 binary nanocomposite coatings were fabricated on steel C1045 substrates by jet electrodeposition. The samples were then processed using self-made laser processing equipment to investigate the influence of long-pulse laser processing parameters variation on samples’ surface morphology, roughness and wettability. Additionally, the properties of samples before and after laser processing were analyzed and characterized. The results showed that the surface morphologies, surface roughness and wettability of samples were affected by laser output power, pulse width and spot-to-spot distance variation. A convex dome was formed on the samples’ surface at a low laser output power and a suitable pulse width, while a dimple was formed on the samples’ surface at a high laser output power. The surface roughness and water contact angle of samples increased with the rise in laser output power or pulse width. The water contact angle decreased with the rise in the spot-to-spot distance, and the water contact angle reached a maximum value of 139.8° with a laser output power of 50 W, a pulse width of 100 µs and a spot-to-spot distance of 150 µm. The samples after laser processing exhibited a higher wettability, microhardness and wear resistance compared to those of the normal samples. The microhardness of the heat-affected zone reached a maximum value of 812.1 HV0.1, and the wear scar width of the samples reached a minimum value of 360.5 µm. However, after laser processing, the samples’ seawater corrosion resistance decreased slightly.