Electrodeposition and characterization of Co-Cr alloys from gluconate-formate bath

Abstract

The electrodeposition of Co-Cr alloys were carried out successfully from aqueous baths based on the following constituents: CoSO4.7H2O 30,CrCl3.6H2O 100, NH4Cl 50, H3BO3 30,C6H11O7Na 80 g/L and 100 ml HCOOH. The effects of several operating parameters such as; current density, bath composition, pH and temperature on the potentiodynamic cathodic polarization curves, cathodic current efficiency of the deposited alloy as well as on the alloy composition were investigated. The codeposition of Co and Cr from these electrolytes follows the irregular type of deposition. The Co percentage in the deposits increases with either decreasing Cr(III) / Co(II) concentration ratio in the bath or increasing the current density. The morphology of the as-deposited Co-Cr alloys was examined using a scanning electron microscope (SEM) while the structure of the alloys was examine using both X-ray diffractions and anodic linear stripping voltammetry (ALSV) techniques.