Nano mixed particles enhanced Nickel-Cobalt composite coatings by scanning jet electrodeposition

Abstract

Jet electrodeposition has the characteristics of rapid deposition with high current density, but faces the problem of tip discharge, which causes a decrease in coating surface uniformity and flatness. In this paper, scanning jet electrodeposition was adopted to optimize the tip discharge. The different nanoparticles were mixed as the reinforcing phase of Ni-Co alloy coating. Nano-CeO2/Nip mixed particles enhanced Nickel-Cobalt composite coatings on 304 stainless steel by scanning jet electrodeposition. The morphologies, texture orientation, microhardness, coating adhesion, and corrosion resistance of Ni-Co-CeO2/Ni composite coatings were characterized. The addition of nano-mixed particles (CeO2/Nip) changed the morphology of Ni-Co-CeO2/Nip composite coating from large cellular protrusion structures to fine granular structures and improved the uniformity of the composite coating. Compared with Ni-Co alloy coating, the microhardness increased from 467.8 to 524.7 HV, the adhesion between the substrate and the coating increased from 20.6 to 28.9 N, and the corrosion current density decreased from 2.413 × 10−5 to 5.598 × 10−6 A·cm−2 in Ni-Co-CeO2/Nip (4 g/L) composite coating, indicating that nano-mixed particles (CeO2/Nip) improved the mechanical properties and corrosion resistance of Ni-Co alloy coating in scanning jet electrodeposition.