Enhancing corrosion and wear resistance of Nickel–aluminum bronze through laser-cladded amorphous-crystalline composite coating

In this study, laser-cladding technology was used to create Cu-based amorphous–crystalline composite coatings on the surface of Nickel-aluminum bronze (NAB), and the microstructure, mechanical properties, corrosion and wear resistance of the coatings were systematically investigated. The coatings consisted of a combination of amorphous and intermetallic compounds, with a positive correlation observed between the amorphous content and the laser scanning speed. Microstructural observations confirmed excellent metallurgical bonding between the coatings and substrate without any noticeable defects. Furthermore, electron back-scatter diffraction testing demonstrated a gradient structure from the substrate to the coating, confirming its composition as an amorphous–crystalline composite. At a laser scanning speed of 20 mm/s, the volume fraction of the amorphous phase of the coating reached 68.8%, with a microhardness approximately 4.5 times higher than that of the substrate and an average friction coefficient half that of the substrate. Moreover, the coatings showed a shift in corrosion potential by 149 mV with nearly an order-of-magnitude decrease in corrosion current density.