Synthesis of strontium hexaferrite (SrFe12O19) by self-propagating high-temperature synthesis (SHS) method and investigation of the effect of milling on morphology and magnetic properties

In this research, strontium hexaferrite (SrFe12O19) was synthesized using the self-propagating high-temperature synthesis (SHS) method, and its structural and magnetic properties were investigated. Raw materials such as strontium peroxide (SrO2), iron (Fe), and iron (III) oxide (Fe2O3) were used to prepare green compact. The current research investigated the effect of milling time and speed on the morphology and magnetic properties of strontium hexaferrite, and the optimum temperature for calcination was obtained. X-ray diffraction (XRD), vibrating magnetometer (VSM), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) were used to study the mentioned parameters and choose the optimal conditions for the synthesis of strontium hexaferrite. Milling at speeds of 100, 200, and 300 rpm for 30 and 90 min was investigated. Also, calcination was performed at temperatures of 1000, 1100, 1200, and 1300 degrees C for 90 min to obtain the optimal temperature. According to the results of VSM analysis, the sample milled at 300 rpm for 90 min and calcined at 1200 degrees C for 90 min had the highest magnetic properties. Magnetic saturation (M-S), magnetic remanence (M-r), and coercivity (H-C), with values of 56.43 emu/g, 30.85 emu/g, and 5705.96 Oe, were obtained for this sample. Also, FE-SEM images showing the formation of hexagonal plates with an average particle size of 380 nm after calcination were obtained for the sample with optimal parameters. TEM and HRTEM images also showed the formed particles of strontium hexaferrite with hexagonal morphology.