The effect of different alkali metal chloride fluxes on the phase formation and properties of Sr-based hexaferrite, SrFe12O19 materials

Abstract

In order to prepare SrFe12O19 materials, the raw materials, SrCO3 and Fe2O3 were annealed with different alkali metal chlorides such as LiCl + NaCl, LiCl + KCl, LiCl + CsCl, NaCl + CsCl, and KCl + CsCl as the flux at 1200 °C for 5 h. The structural features of SrFe12O19 materials prepared without flux have been compared. The phase formation and the properties of the SrFe12O19 materials are sensible to the fluxes used in the synthesis process. The fluxes, NaCl + CsCl, and KCl + CsCl produced good quality nanocrystalline SrFe12O19 materials, whereas the LiCl + NaCl, LiCl + KCl, and LiCl + CsCl flux reaction mixtures yielded mixed phase materials. The NIR reflectance of the present series materials varies regardless of the fluxes used in the synthesis. Relatively high NIR reflectance is noted for the KCl + CsCl flux annealed SrFe12O19 materials even though KCl + CsCl and NaCl + CsCl fluxes yielded single phase SrFe12O19 materials. A typical hard ferromagnetic hysteresis loop opening is observed at room temperature (300 K) for the NaCl + CsCl and KCl + CsCl fluxes annealed SrFe12O19 materials. Plate-like hexagonal grains with different size are observed in the microstructural images of the NaCl + CsCl flux annealed SrFe12O19 materials. The molten salt flux method employed in the present work is simple and efficient for the production of phase pure SrFe12O19 materials using NaCl + CsCl, and KCl + CsCl as the flux, that are worth for different high-tech applications including satellite communications, magneto-optical recording, data storage, and electrical and microwave devices.