Fabrication of Ni-SiC composite coating with coral-like hierarchical structure via magnetic field-assisted jet electrodeposition for efficient oil/water separation

A Ni-SiC composite coating was effectively synthesized on a stainless-steel substrate through a jet electrodeposition technique integrated with a magnetic field, and then utilized for oil/water separation. Guided by an external magnetic field, the magnetically responsive nickel components loaded with hydrophilic SiC were incorporated into the coating, creating a coral-like micro-nano hierarchical rough structure. The functionalized mesh demonstrated remarkable superhydrophilic properties and submerged low-adhesion superoleophobicity. Appropriate processing parameters were identified by analyzing how electrodeposition duration and voltage influence the surface topography as well as the wettability associated with the Ni-SiC-coated mesh. The results indicated that the Ni-SiC-coated mesh prepared at 30 V for 10 min exhibited a WCA of 0° and a UOCA of 152.2°. Ni-SiC-coated meshes fabricated at a lower voltage required a deposition time of 30 min to achieve superhydrophilicity and underwater superoleophobicity. The mesh achieved high efficiency along with superior purification levels for various oil/water emulsions and sustained a stable separation performance (exceeding 95%) after 50 cycles. The treated substrate maintained its functionality in aggressive media. In natural conditions, the Ni-SiC-coated mesh still retained its outstanding superhydrophilicity and underwater superoleophobicity after three months of storage. In addition, the Ni-SiC-coated mesh maintained a UOCA of more than 150° after water erosion for 10 h.