Preparation of Rare-Earth Permanent Magnetic Strontium Ferrite by Microwave Sintering Process

Abstract

In this paper, the green body was prepared by pre-roasted material of strontium ferrite, adding 0.2 to 9% the rare earth additive, by wet milling and forming into pellets Φ30×10 mm under magnetic field. Then, the green body was sintered separately by microwave sintering (MS) method and conventional sintering (CS) technique. The results showed that: the strontium ferrite samples with the same magnetic properties Br and (BH) max were 420 ± 10mT and 33.0 ± 2 kJ/m 3) were synthesized by microwave sintering (MS) method against conventional sintering method, the sintering temperature and time were reduced 150~300°C and 5~6h. Therefore, microwave sintering method will significantly decrease energy consumption. Further analysis revealed that the major improvements in microwave sintering were the material microstructure, the grain size was significantly reduced, the magnetic domain short-range order was increased so that the degree of orientation was increased, and although the fusion was existed between grains, the grain boundaries did not disappear.

Effects of Atmosphere on the Microstructure and Magnetic Properties of Strontium Ferrites with Microwave-Assisted Sintering

“…Their magnetic properties depend on the preparation condition, such as sintering temperature, sintering Minglin Jin jml@sit.edu.cn 1 Department of Material Science and Engineering, Shanghai Institute of Technology, Shanghai, 201418, China atmosphere, and soaking time as well as the type of the substituted ions [1][2][3][4][5]. The sintering processes have great effects on the microstructure, crystalline alignment, densification, and other properties.…”