Nickel Alloying Effect on Formation of Cobalt Nanoparticles and Nanowires via Electroless Deposition under a Magnetic Field

Abstract

Co-Ni nanowires 40–100 nm in diameter with several dozen μm of length were prepared via electroless deposition under a magnetic field. The formation of Co-Ni nanowires was investigated by an in-situ mixed potential measurement and a cyclic voltammetry combined with a quartz crystal microbalance electrode. These electrochemical measurements revealed that the deposition rate of nickel on nickel is lower than that of cobalt on cobalt. Nickel works as an inhibitor in a growth process of Co-Ni alloys. Thus, the thickness of Co-Ni alloy nanowires is drastically reduced by the addition of Ni(II) in solution. The morphology of Co-Ni nanowires is also strongly affected by the magnetization of Co-Ni alloy nanoparticles which are precursors in the formation of nanowires. Both the magnetization and the deposition rate in Co-Ni alloys are the key parameters to control the aspect ratio and surface morphology of nanowires.