Part of the book: Materials Science and Technology
Part of the book: Materials Science
Magnetite, Fe3O4 (FeIIO-FeIII2O3), is a member of the spinel group as well as a common ferrite with a cubic inverse spinel structure. Aqueous colloidal solutions of Fe3O4, i.e. water-based Fe3O4 magnetic fluids, have attracted substantial attention in biomedical applications, such as drug delivery, magnetic resonance imaging, and magnetic hyperthermia. In this study, to readily prepare water-based magnetic fluids with biocompatible dispersant-coated Fe3O4 nanoparticles that are stably dispersed in water medium, a mechanochemical synthesis method was developed. In this method, an iron-free citric acid solution is milled in a tumbling ball mill with steel balls at room temperature, reducing the production costs and environmental impacts. The initial gas phase in the milling vessel is air, and pressure is varied to control the formation of Fe3O4 nanoparticles. Although no iron species are contained in the starting solution, Fe3O4 nanoparticles form in the solution according to the reaction mechanism based on the oxidation-reduction processes of the corrosion of steel. At the same time, the Fe3O4 nanoparticle surface is modified with citrate ions, resulting in a stable dispersion. The magnetic fluids prepared using this mechanochemical method possess good induction heating properties in an alternating current magnetic field.
Part of the book: Magnetic Spinels