A comparative study of the microstructure and corrosion resistance of Fe-based/B4C composite coatings with Ni-added or Cu-added by vacuum cladding

In order to improve the corrosion resistance of Fe-based/B4C composite coating, Fe-based/B4C composite coating without and with Ni-added or Cu-added were prepared by vacuum cladding, and the corrosion behaviour of the coatings in 0.5 mol/L HCl solution was studied. The results showed that the coatings were metallurgically bonded to the steel substrate. Due to the additions of Ni or Cu, the coating matrix underwent phase trans-formation and formed martensite, the morphology of hard phases (carboboride and boride) also changed into irregular blocks, and hard phases in Cu-added coating was finer in size. After 1 and 7 days of immersion corrosion, the corrosion morphology of coating with Ni-added or Cu-added presented a small number of corrosion holes compared with the non-added coating, indicated that the additions of Ni or Cu significantly improved the corrosion resistance of the coating. And the surface corrosion of Cu-added coating was the shal-lowest, showing the best corrosion resistance.

Automated summary

Fe-based/B4C composite coatings without and with Ni or Cu additives were prepared by vacuum cladding, and their corrosion behavior in 0.5 mol/L HCl solution was investigated. The results showed that the coatings were metallurgically bonded to the steel substrate. The addition of Ni or Cu resulted in phase transformation in the coating matrix, formation of martensite, and changes in the morphology of hard phases. The corrosion resistance of the coatings was significantly improved by the additions of Ni or Cu, with the Cu-added coating exhibiting the best corrosion resistance.