چكيده به لاتين
In this research, the synthesis of strontium hexaferrite (SrFe12O19) by high temperature self-propagating combustion method (SHS) and its structural and magnetic properties have been investigated. This material, one of the M-type hexafrrites and considered among hard magnetic materials, has magnetic coercivity, axial anisotropy, and high Curie temperature. Excellent chemical stability and good corrosion resistance are other features of this material. In this method, the raw mixture was first mechanically activated by grinding, and then the final product was prepared by high-temperature self-propagating combustion synthesis (SHS). Raw materials such as strontium peroxide (SrO2), iron (Fe), and iron (III) oxide (Fe2O3) were used to prepare the raw compact. In this research, the effect of milling time and speed on the magnetic properties of the synthesized strontium hexaferrite was investigated. The optimal temperature for calcination was also obtained to modify and improve the crystal structure. X-ray diffraction (XRD), vibrating magnetometer (VSM), scanning electron microscope (SEM), and field emission scanning electron microscope (FE-SEM) 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 was investigated for 30 and 90 min. Also, the calcination temperature of 1000, 1100, and 1200 °C was checked for 90 min. Finally, based on the obtained results, milling at a speed of 300 rpm for 90 min and a calcination temperature of 1200 °C for 90 min were selected as optimal parameters, and magnetic properties such as magnetic coercivity (HC), magnetic Saturation (MS) and magnetic remanence (Mr) had values of 5705.92 Oe, 56.43 emu/g and 30.85 emu/g, respectively. According to the FE-SEM results, hexagonal disc-shaped particles with an average size of 380 nm were obtained for the sample with optimal parameters after calcination. Also, strontium hexaferrite was synthesized using strontium carbonate (SrCO3) instead of strontium peroxide (SrO2) in the initial mixture. The milling speed was 100 rpm, and the duration was 90 min. According to the results of XRD and VSM analyses, after calcination of the synthesized sample at 1000 °C for 90 min, single-phase strontium hexaferrite with magnetic coercivity (HC), magnetic saturation (MS), and magnetic remanence (Mr), respectively, 3106.58 Oe, 43.05 emu/g and 22.96 emu/g were obtained.
