Application of Co–Ni–P Coating on Grain-Oriented Electrical Steel

Abstract

An electroless plating of Co–Ni–P was applied to a grain-oriented electrical steel substrate, resulting in a power loss improvement of $\sim 9$ %–11%. The mean thickness of the coating was found to be $2.15\,\pm \,0.15~\mu \text{m}$ from environmental scanning electron microscopy images. Shifts of the magnetostriction stress sensitivity curves showed that stress was acting on the substrate and was corroborated by a shift in X-ray diffraction (XRD) peaks and narrowing of the domains after the samples were coated. The magnetic property measurement system results confirmed the magnetic nature of the coating and XRD results showed peaks of $\alpha $ -iron in the uncoated sample, $\alpha $ -iron-cobalt and $\alpha $ -iron in the Co-Ni-P-coated sample. The Talysurf profilometer showed a decrease in surface roughness values after coating the sample, which reduced the hysteresis loss.