A study on the effect of reducing agent content on the thickness of electroless Ni₃P deposits on B₄C nanoparticles

Faculty of materials and manufacturing processes, MUT, PO Box 15875-1774, Tehran, Iran
e-mail: al.alizad53@gmail.com

Received: 17 May 2012
Accepted: 18 December 2012

Abstract

Deposition of Ni₃P nano-scale layer on B₄C nanoparticles in four contents of sodium hypophosphite as reducing agent including 5, 10, 15 and 30 g/l via electroless coating were done to investigate the effect of reducing agent content on the coating thickness of deposited Ni₃P. The bath pH and temperature was 5.5 and 85 °C, respectively and the coating time was 25 min. The powders were characterized by transmission electron microscopy (TEM) and the phases present were revealed by X-ray diffraction (XRD). Nickel and phosphorous contents of the coatings were measured by inductively coupled plasma analysis (ICP). The results revealed that by increasing the reducing agent content from 5 g/l to 30 g/l the average coating thickness increased from 19 nm to 28 nm. Although the increasing effect of adding sodium hypophosphite content was preserved, there is a critical amount for sodium hypophosphite content to increase the coating thickness.