RAPID PREPARATION OF COBALT FERRITE/COBALT IRON NANOCOMPOSITES BY HYDROGEN REDUCTION

Abstract

This article explores the preparation of cobalt ferrite (CoFe2​O4​) and cobalt-iron (CoFe) nanocomposites through a rapid and efficient hydrogen reduction method. Nanocomposite powders were prepared from cobalt ferrite synthesized by gel-combustion and subjected to a prior milling process to enhance magnetic properties. The reduction was carried out in a tubular furnace under a hydrogen atmosphere (99.99% purity) at 350°C, with thermal treatment times ranging from 10 to 30 minutes. Previous studies indicate that cobalt ferrite/cobalt-iron nanocomposites exhibit high magnetization and coercivity, as well as effective exchange coupling between the magnetic phases. Our results demonstrated that the transformation of cobalt ferrite into cobalt-iron is feasible and highly efficient, with approximately 40(2)% reduction in just 10 minutes and about 90(6)% in 20 minutes, confirming the rapidity of the process. The formation of a core-shell structure with a metallic cobalt and iron layer over the ferrite particles is proposed as the main mechanism for improved magnetic properties. This work highlights the feasibility of a quick and effective production method for nanocomposites with potential for various applications.