Preparation of superhard nanometer material cBN reinforced Ni-W-P nanocomposite coating and investigation of its mechanical and anti-corrosion properties

Abstract

In this work, superhard nanoparticle cubic boron nitride (cBN) was introduced into Ni-W-P bath, and Ni-W-P/cBN composite coatings with different cBN concentrations were successfully prepared by pulse electrodeposition technique. In addition, the effects of different cBN dosages on the wear resistance and corrosion resistance of Ni-W-P/cBN composite coatings were also studied. Vickers microhardness tester and multifunctional material surface testing machine was used to evaluate the hardness and wear resistance of composite coatings. The corrosion resistance properties of the coatings were analyzed and characterized by EIS and potentiodynamic polarization. The results show that when the cBN content in the bath is 2 g/L, the comprehensive properties of the Ni-W-P/cBN composite coating are improved most significantly. Benefiting from the mechanical enhancement effect of cBN, the microhardness of the Ni-W-P/cBN (2 g/L) composite coating is increased to 543.0 HV, and the friction coefficient is reduced to 0.39 (the original Ni-W-P coating has a lower Microhardness 343.4 HV and higher friction coefficient 0.68). Furthermore, it is found that the corrosion resistance of the composite coating is greatly improved by electrochemical technology. The corrosion potential of Ni-W-P/cBN (2 g/L) composite coating is − 0.46 V, corrosion current is 9.3 μA/cm2 and corrosion rate is 0.11 mm/ year. (The corrosion potential of Ni-W-P coating is −0.53 V, corrosion current is 30.4 μA/cm2 and corrosion rate is 0.36 mm/ year).