Preparation and characterisation of nickel–nano-B₄C composite coatings

Abstract

Ni–B₄C composite coatings on carbon steel surfaces with various contents of nano-B₄C particulates were prepared by electrodeposition in Ni plating bath containing nano-B₄C particulates. Microhardness, scanning electron microscopy (SEM), Tafel and electrochemical impedance spectroscopy (EIS) measurements were used to compare pure nickel coating and Ni–B₄C composite coatings. The microhardness of Ni–B₄C coatings is higher than that of pure Ni coating, together with the microhardness of the composite coatings increases with the increase of the content of nano-B₄C particulates. The effects of various contents of nano-B₄C particulates on the corrosion resistance were investigated and it was found that the best anticorrosion property of Ni–B₄C composite coatings is at 6 g L⁻¹ B₄C in the bath formulation.

Keywords:

• Composite coatings
• Electrodeposition
• Microhardness
• Corrosion resistance

This paper is financial supported by the Natural Science Foundation of China (nos. 50571059 and 50615024), Program for New Century Excellent Talents in University (no. NCET-07-0536) and Innovative Research Team in University (no. IRT0739).