Study of Alloys Addition to the Electrodeposited Nanocrystalline Cobalt

Abstract

Cobalt and its alloy have been identified as potential candidates for replacing hexavalent Chromium plating in corrosion resistant coating in acidic environment. In this study, the effect of alloys addition towards elemental composition, crystallographic structure characterization, surface morphology, hardness and potentiodynamic polarization of the cobalt alloys coatings is reported. Addition of Nickel (Ni) and Iron (Fe) to the Cobalt (Co) coatings are deposited on stainless steel substrate by electrodeposition method. The deposition is performed at acidic environment of pH 3. The granule sizes of cobalt alloys prepared by electrodepositionmethod are in the range of 34.95 nm72.08 nm. The microhardness of CoNiFe is the highest (267.8 HV) compared to Co and CoFe. CoNiFeperforms the smallest corrosion rate with 1.322 mmpy. It is found thatthe addition of Ni and Fe into pure cobaltimproves the hardness and corrosion behavior.