Hydrothermal synthesis of magnetite: investigation of influence of aging time and mechanism

Magnetite (Fe₃O₄) particles are prepared by a hydrothermal method using ethylene glycol as the solvent. Aging time is a very important factor in the reaction process. The properties and morphology of the products with different aging times are investigated. In the initial stage of the reaction (1 and 2 h), the main powders were iron hydroxides. Fe₃O₄ particles generated (3 h) and grew into spherical shapes (4-10 h) with the extended aging time. The particle size and the specific saturation magnetisation also varied with aging time. By analysing the powders and the liquids during the reaction, a probable mechanism is studied.