Influences of Boron Concentration on Mechanical Properties of Ni-W-B Composite Coatings

Abstract

Ni-W-B alloy coating containing amorphous boron particle were fabricated by direct current electrodeposition on low carbon steel substrates. The effect of boron concentration in the plating bath on the surface morphology, the overall boron content in the deposited layers and the hardness of the resulting coating layer were investigated. Scanning electron microscopy (SEM) revealed that the surface morphology of the Ni-W-B coating layer was largely modified by the boron particle loading in the electroplating suspension. Distinct nodular structures were observed in these samples. Energy dispersive X-ray spectroscopy (EDS) spectra suggested that the overall boron content in the coating layer increased with increasing boron particle loading from 1 to 3 g/L. Too high boron particle loading of 10 g/L resulted in lower overall boron content. The highest hardness of 680.86 ± 17.67 Hv was obtained from Ni-W-B/B coating layer fabricated using the boron particle loading of 5 g/L.