Influence of pulse frequency on corrosion resistance and mechanical properties of Ni-W/B4C composite coatings

Abstract

In this research, the effects of different pulse frequencies on the properties of Ni-W/B4C composite coatings are investigated in detail. First, we evaluate Ni-W coatings prepared from different bath compositions and select suitable electrolyte as bath solution. Then, the purchased boron carbide nanoparticles are characterized and their dispersion and suspension properties in bath electrolyte are verified. After that, Ni-W/B4C composite coatings are manufactured through different pulse frequencies (1, 10, 100 and 1000 Hz) and the prepared alloy coatings are characterized in detail. The results show that when the pulse frequency is increased from 1 Hz to 1000 Hz, the grain size of coatings decreases by 40%, the content of nickel in the coating decreases 3%, the content of W increases by 1.5%, the content of B4C particles is increased, and the roughness of the coating decreases significantly. In addition, the micro-hardness test, tensile test, impact test, bending test and reciprocating wear test are used to explore the mechanical properties of composite coatings, the water contact angle test and porosity test are used to study the surface properties, and the electrochemical test are adopted to predict the corrosion resistance. The results show that the composite coating prepared at 1000 Hz has the best mechanical properties, while the composite coating prepared at 100 Hz has the best corrosion resistance.