Preparation of sub-micron Fe Package Co hollow microspheres

A new method to prepare Co hollow coated Fe microspheres is presented in this article. The Fe coated Co particles with core-shell structure were primarily synthesized by chemical reducing reaction using nano-Fe particles as a template and hydrazine hydrate as reducing agent and then hollow Co shell was prepared after dissolving Fe cores using HCl solution. Further, using hollow Co shell as a template and NaBH₄ as reducing agent, Co coated Fe composite shell sub-micron hollow spheres were synthesized by chemical reducing method. Studies found that chemical bond would be formed easily between the Co coated Fe hollow microspheres during reducing iron process, and the generation of chemical bond can be effectively prevented by reducing the concentration of reactants, reaction temperature, and increasing the pH value of reaction solution to inhibit the independent nucleation of Fe particles in the bath.