Synthesis and Characterization of Nano-crystalline Calcium Hexaferrite Particles by Mechano-Thermal Method

Calcium hexaferrite was synthesized using high-energy planetary ball milling of a mixture of CaCO3 and Fe2O3 powders for 10 hours followed by calcination at 1175 C-a similar to for 1 h. Effects of Fe2O3/CaCO3 molar ratio, mechanical activation and dopant addition on the phase evolution, morphology, and magnetic properties of the products were studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) technique equipped with an energy dispersive spectrometer (EDS), and vibrating sample magnetometer (VSM). XRD results showed that addition of La2O3 in the samples lead to the formation of stabilized calcium hexaferrite particles with a mean crystallite size of 54 nm. Moreover, the formation of calcium hexaferrite was acknowledged at Fe2O3/CaCO3 molar ratio of 5. SEM micrographs showed agglomerated particles of calcium hexaferrite with a mean particle size of 1.5 mu m. Nano-crystalline Ca0.8La0.2Fe12O16 particles show saturation magnetization of 14 emu/g and coercivity of 500 Oe.