Silicon nitride nanoparticles reinforced the corrosion resistance of Ni-Cu composite coating in simulated seawater solution

A new type of Ni-Cu/Si 3 N 4 nanocomposites was prepared by pulse electrodeposition technology, which can be used for corrosion protection in seawater environment. XRD , SEM, AFM, EDS and XPS were used to study the structure, morphology, and surface composition of the deposited layers. The hardness and anti-corrosion performance of the deposits were evaluated using a microhardness tester and an electrochemical workstation. Meanwhile, the samples were characterized by EIS , SEM, EDS and XPS after immersion in simulated seawater for 7 days, 14 days, and 28 days. The results show that the average crystallite size of the nanocomposite with face-centered cubic structure is 13.2 nm, and has a dense granular nodular structure without obvious defects. EDS and XPS demonstrated the successful embedding of Si 3 N 4 nanoparticles with uniform distribution in the coating. Besides, it was found that embedding Si 3 N 4 particles in Ni-Cu alloy coatings can significantly strengthen the microhardness and anti-corrosion performance of the material. Furthermore, the Ni-Cu-Si 3 N 4 (0.7 g·L −1 ) nanocomposite exhibited excellent corrosion resistance even after immersion in simulated seawater medium for 28 days.