Effect of current density and deposition time on the corrosion and wear resistance of Ni–W alloy coatings

Abstract

AbstractThe current study investigated the effect of current density and plating time on structure and properties of Ni–W coating obtained by direct current electro-codeposition from a new deposition bath. Phase formation and microstructural changes of Ni–W alloy coatings were analysed by X-ray diffraction and scanning electron microscopy, respectively. Hardness and wear studies revealed better surface-mechanical properties with increasing coating time or current density due to higher W content and fine structure. Hardness values of coatings ranged from 346 Hv to 770 Hv and the coating obtained with 60 mA · cm−2, 60 min showed the highest hardness (∼770 Hv) due to higher W content and finer structure. Potentiodynamic polarization testing and EIS study in NaCl solution revealed that finer morphology/strain tends to decrease corrosion resistance; whereas, higher W content improves it.