The influence of solvent composition in the sol-gel synthesis of cobalt ferrite (CoFe2O4): A route to tuning its magnetic and mechanical properties

Abstract

This work presents a successful, environmentally-friendly route for tuning the magnetic and mechanical properties of CoFe2O4 sintered ceramics. The precursor powders were prepared from mixtures containing 100, 50 and 20% water, with the remaining volume composed of isopropanol. The synthesised powders were pressed into pellets and sintered at 1150 and 1200 °C. SEM micrographs indicate that the solvent exerts a major influence over the morphology of the ferrite grains. Vickers hardness shows a maximum for products from a medium containing 50% water, which could be directly related to the smaller average size of the CoFe2O4 grains. The coercivity of the pellets is strongly influenced by the reactional medium, with a maximum of 501.7 Oe (sample prepared at 20% water and fired at 1150 °C). This work opens up possibilities for fine tuning of the final properties of CoFe2O4 sintered ceramics, further enabling the utilisation of this material in advanced applications.