Temperature, current density and cobalt concentration effects on electrodeposited anticorrosive cobalt-tungsten alloys using factorial experiment design and ANOVA techniques

ABSTRACT

Corrosion processes can compromise the durability of metallic materials. One way to minimise the effects of corrosion is to coat them with corrosion-resistant alloys. In this study, Co–W alloys were produced by electrodeposition and their anticorrosive performance was evaluated at different levels of current density, Co bath concentration and bath temperature, using factorial experiment design and ANOVA techniques. This evaluation consisted of measuring corrosion current and using electrochemical impedance spectroscopy. Adherent and corrosion resistant alloys were obtained at the lowest temperature of experimental design (25°C) and current density (10 mA cm⁻²) values. From the corrosion tests, X-ray Diffraction and Scanning Electron Microscopy analysis it was possible to conclude that the increase in the tungsten percentage in the composition of the alloy generated an increase in corrosion resistance. Although the alloys’ chemical composition has influence on the corrosion resistance, their physical aspect, such as the presence of cracks, are more significant for the resistance to corrosion.

KEYWORDS:

• Anticorrosive alloys
• coating materials
• Co–W alloy
• electrodeposition
• corrosion current

Acknowledgements

The authors would like to thank FAEPEX/UNICAMP and FAPESP n° 2013/25212-0 for financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.