Preparation of Strontium Hexaferrite Nanocrystalline Powder by Dynamic Hydrogen Heat Treatment and Recalcination

M-type hexaferrites with chemical formula of MFe12O19 (M = Ba, Sr and Pb) have been widely used as permanent magnets due to their low cost of production, high uniaxial magnetic anisotropy and excellent corrosion resistivity [1]. The conventional method of production of this material is solid-state reaction between SrCO3 and Fe2O3 at temperatures higher than 1100°C [2]. In order to get single domain particles of strontium hexaferrite, different synthesis techniques have been developed such as co-precipitation [3], self-propagating high temperature synthesis [4] and sol–gel auto combustion [5]. Static gas heat treatment and re-calcination is a method produces hexaferrite nanoparticles from conventionally synthesized powder and have been investigated in last decade [6]. In this work the effects of dynamic hydrogen heat treatment and re-calcination on the phase composition, microstructure and magnetic properties of conventionally synthesized strontium hexaferrite have been studied systematically