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

The electrodeposition of Co-Cr alloys were carried out successfully from aqueous baths based on the following constituents: cobalt sulphate, chromium chloride, ammonium chloride, boric acid, sodium gluconate and formic acid. 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.