Effect of current density and deposition time on Ni-W alloy coating and evaluation of corrosion and wear resistance

Abstract

The current work investigated effect of current density and plating time of electrodeposited Ni-W coating on their structure-properties. Ni-W alloy coatings were obtained by DC electro-codeposition technique with varying current density and deposition time from a new deposition bath followed by evaluation of surfacemechanical (microhardness and wear) and electro-chemical properties of the coated samples. Phase formation, microstructural changes of Ni-W alloy coating with deposition current density and deposition time were analyzed by XRD and SEM study respectively. Apart from phase identification, from XRD peak broadening, fineness of the structure was calculated. Microstructure analysis revealed change in coating morphology with change in current density and deposition time. Hardness and wear studies were also taken up and it was observed that with increasing coating time or current density, surface-mechanical properties exhibit better results due to higher W content and fine structure. Corrosion study of coated samples was carried out by potentiodynamic polarization test in 3.5 wt.% NaCl solution. Results indicated better corrosion resistance for samples deposited with higher current density and deposition time