Electrodeposition & Characterization of Co-W Alloys

Abstract

Cobalt-tungsten alloys have been electroplated from alkaline bath solutions under different plating and bath conditions. Diammonium hydrogen citrate and dimethyl sulfoxide in the bath solution have produced good quality deposits. The hardness and magnetic properties of the alloys are found to depend on composition and heat treatment. Cyclic voltammetric and spectral studies revealed the complexation of cobalt ions with diammnonium hydrogen citrate in the plating bath solution. Dimethyl sulfoxide has activated the codeposition of tungsten. The alloys are amorphous under plating conditions and become partially crystalline upon heat treatment. AES analysis revealed the absence of oxygen, chlorine and carbon on the surface of the coated alloys. Working conditions were optimized to get good quality deposits with appreciable coercivity and hardness values.