Collaborative fabrication of high-hardness and self-lubricating Ni/Ni-Co coatings reinforced by SiC nanoparticles and 2D materials using electrochemical deposition process

• Innovate a multi-nanomaterials combination strategy to achieve unique-structured lubricating coatings. • 2D materials change coating surface texture and SiC size impacts hardness significantly. • Unveil the interaction mechanisms among 2D materials, SiC size, and Ni-Co ratio. The insufficient hardness and poor lubricity of Ni mold cause surface damage to polymer structures during demolding due to friction and adhesion between the polymer and Ni mold surface. Existing 2D material-based studies on improving Ni mold performance usually focus on a single material, neglecting the effects of particle size and material interactions on coating properties. This study innovatively prepares low friction coefficient (COF) and high-hardness coatings by incorporating high-strength SiC nanoparticles and self-lubricating 2D materials (MoS 2 , WS 2 , and BN) into Ni-based electrodeposition. It comprehensively investigates the impacts of 2D material type, SiC particle size, and Ni-Co ratio on coating microstructure, mechanical and tribological properties. The results indicate that 2D materials alter the surface textures from spherical clusters to fibrous structures with increasing Ni-Co ratio, following the substantial columnar grains changing into equiaxed grains and demonstrating grain refinement. SiC particle size greatly affects the coating’s hardness, and SiC 20-MoS 2 50 coatings fabricated in Ni: Co = 9.25:0.75 achieve a maximum hardness of approximately 632 HV, 3.61 times higher than that of pure Ni system. The COF is jointly determined by the Ni-Co ratio, SiC particle size, and 2D material type. At Ni: Co = 5:5, the COF of all 2D material-reinforced coatings drops notably. MoS 2 and WS 2 promote the formation of a dense tribofilm, reducing abrasive and adhesive wear. The SiC 20-MoS 2 50 coating achieves a minimum COF of approximately 0.05, a 90 % reduction compared to the pure Ni system. The friction mechanism shifts from abrasive ploughing and severe adhesion for pure Ni system to slight abrasive and oxidative wear for Ni: Co = 5:5, significantly enhancing the wear resistance. This study clarifies the interactive mechanisms among 2D materials, SiC particle size, and Ni-Co ratio on coating properties, driving the development of high-performance mold coatings and defect-free polymer device molding.