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

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 degrees 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 degrees 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.