ABSTRACT The work demonstrates the production of nano crystals of cobalt in bulk quantities in aqueous medium using hydrazine as the reducing agent. Preparation of Co nano powders of 30 - 70 nm of 99.99% purity was accomplished from 0.25 - 2 M CoSO4 solutions in batch scale of 0.1 to 1 kg. The results of characterization studies using XRD, SEM, TEM indicate the formation of finer particles with increase in concentration of cobalt ions in solution and dominance of fcc cobalt in room temperature reduction. VSM results revealed a higher saturation magnetization of the nano cobalt at 100 K to be comparable to that of the bulk metal.
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