Pulse and Pulse Reverse Electrodeposition of Cubic, Tetragonal and Its Mixed Phase of Ni-W Alloys for Corrosion Applications

Abstract

Ni-W alloy coatings on mild steel substrate with various crystalline structures were prepared using pulse and pulse reverse electrodeposition method for corrosion protection application. The co-deposition behavior of tungsten and basic electrochemical information of electrolytes were confirmed through cyclic voltammetry studies. The crystalline nature, alloy phase and it is crystal (cubic and tetragonal) phase transformations were confirmed using X-ray diffractions. The corrosion resistance performances of the deposits were studied using Tafel polarization and electrochemical impedance studies. Correlation between the crystal structures and its corrosion resistance performance were explored and tetragonal Ni-W alloy film having better corrosion resistance than cubic Ni-W alloy film. The mixed phase of tetragonal dominated cubic structures in the alloy matrix has the superior corrosion resistance performance. This study confirms the Ni-W alloy films have good corrosion protection and this can be tuned with the modification of crystal structure using various deposition conditions.