Investigations on the thermal stability of co-rich nanocrystalline Co-Cu processed through different modes of electrodeposition

Abstract

Single component nanocrystalline metals are receiving great interest due to excellent mechanical and physical properties. Improvement on the thermal stability is needed for high-performance application, for instance, through the addition of alloying elements. In this paper, bulk deposits of nanocrystalline Co-Cu were processed through different modes of electrodeposition (i.e. combination of pulsed and reverse current). The investigations showed that different modes of electrodeposition have a significant influence on chemical composition, grain size, and microhardness of Corich nanocrystalline Co-Cu deposits. Annealing treatments at various temperatures were employed to investigate the thermal stability. The thermal stability of nanocrystalline Co-Cu was strongly influenced by Cu content and initial grain size, whereas the best result was obtained from deposits produced through the pulsed current. Investigation on the magnetic properties through the MFM observation showed that the as deposited solid solution nanocrystalline Co-Cu exhibits a weak magnetic domain pattern. Improvement on magnetic properties was observed after annealing treatments in the temperature regime, where phase separation and a modulated structure of Co and Cu were detected.