Investigation of Morphology and Structure of Cobalt Oxide (Co<sub>3</sub>O<sub>4</sub>) and Barium Hexaferrite (BaFe<sub>12</sub>O<sub>19</sub>) Synthesized by Sol-Gel

Sol-gel, which can generally be defined as a chemical process in which small molecules of metal alkoxides are used to produce solid materials, is an important nanomaterial synthesis method that has become very popular recently. Objects with different geometries can be coated homogeneously, and pure powders and thin films can be prepared at low temperatures, also attracting attention with its low cost compared to other production methods. In this study, the synthesis of cobalt oxide (Co3O4) and barium hexaferrite (BaFe12O19), which are mostly used in the defence industry for applications such as radar absorption, shielding, stealth, and also for protecting human health from the harmful effects of radar signals, were investigated with the sol-gel method. Cobalt (II) nitrate hexahydrate and ethylene glycol were used as the precursor and solvent in cobalt oxide synthesis. In barium hexaferrite synthesis, iron (III) nitrate nonahydrate Fe(NO3)3·9H2O, barium nitride Ba3N2, and citric acid were used as starting materials. The powders obtained at the end of the synthesis were first examined structurally by X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Differential thermal analysis determined their behaviour towards heat. Particle size analysis was performed. Finally, their magnetic properties, as an important parameter used in radar absorption applications, were investigated with a vibrating sample magnetometer (VSM). Accordingly, when an external field is applied, barium hexaferrite is more magnetically soft and exhibits a strong ferromagnetism behaviour at room temperature.