Fabrication and Enhanced Vickers Hardness of Electrodeposited Co–Cu Alloy Film with High Composition Gradient

Abstract

By applying an oscillating potential wave, we obtained an electrodeposited Co–Cu alloy film in which the Co concentration changed periodically at a short modulation wave length. A triangular Co concentration modulation was observed along the film growth direction. The local composition gradient became as high as 50 at%/µm. The Vickers hardness of the composition gradient film was 380 HV. Because this value was much higher than that of simple electrodeposited Co–Cu alloy films, contribution of the composition-gradient structure to hardness was suggested.

Vickers hardness values of the electrodeposited copper, cobalt, Co/Cu multilayer, simple Co–Cu alloys, and composition-gradient Co–Cu alloy films.