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.
Highlights
The enhanced mechanical, electronic and magnetic properties [1] of metallic nano particles have triggered proposals for applications as high-density magnetic storage devices [2], hall sensors [3], soft magnetic materials exhibiting higher permeability/lower coercivity [4] and heterogeneous catalysts [5]
The work demonstrates the production of nano crystals of cobalt in bulk quantities in aqueous medium using hydrazine as the reducing agent
The results of characterization studies using X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (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
Summary
The enhanced mechanical, electronic and magnetic properties [1] of metallic nano particles have triggered proposals for applications as high-density magnetic storage devices [2], hall sensors [3], soft magnetic materials exhibiting higher permeability/lower coercivity [4] and heterogeneous catalysts [5]. Cobalt nano powders are being tested for site specific drug delivery agents for cancer therapies and in coatings, fuel cells, batteries, DNA circuits and chrome replacement in sporting goods, luxury and consumer products [13]. Many methods, such as decomposition of dicobalt octacarbonyls, pulse current electro-deposition, gas vapor condensation, salts reduced by reducing agent NaBH4 or H2, are used in the preparation of cobalt nano particles [10,11,12,13,14,15,16,17].
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