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Crystallization Behavior, Microstructure and Magnetic Properties of B₂O₃-SiO₂-Fe₂O₃-BaO-SrO Glass-Ceramics

M. Tavoosi, A. Ghasemi, D. Yousefi

Journal of Ceramic Science and Technology, Vol. 7, No. 4 (2016), pp. 469-476

DOI: 10.4416/JCST2016-00063

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Abstract

The preparation and magnetic characterization of B2O3-SiO2-Fe2O3-BaO-SrO glass-ceramics were the goal of this study. In this regard, different mixtures of B2O3, SiO2, Fe2O3, BaO and SrO were melted in the temperature range 1200 – 1350 °C and were quenched between two sheets of cold steel. The as-quenched samples were annealed at 660 and 700 °C for 2 h. The prepared samples were then characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC) and a vibrating scanning magnetometer (VSM). According to the results obtained, fully amorphous phase can be formed in the 20B2O3-10SiO2-25Fe2O3-45BaO, 20B2O3-10SiO2-25Fe2O3-45SrO and 20B2O3-10SiO2-25Fe2O3-22.5BaO-22.5SrO systems. The coercivity and saturation of magnetizationof the as-quenched amorphous samples were estimated at about 120 – 380 Oe and 9 – 12 emu/g, respectively. The coercivity value increased during the annealing process as a result of precipitation of hard magnetic MFe12O19 phase from the amorphous matrix. Although, all of samples showed almost the same saturation of magnetization, the highest value of coercivity (4620 Oe) was achieved in 20B2O3-10SiO2-25Fe2O3-22.5SrO-22.5BaO sample with simultaneous presents of Sr and Ba.

Keywords

Glass-ceramics, crystallization, magnetic materials, hexaferrite.

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