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

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 degrees C and were quenched between two sheets of cold steel. The as -quenched samples were annealed at 660 and 700 degrees 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 2oB(2)O(3)-10SiO(2)-25Fe(2)O(3)-45Ba0, 20B(2)O(3)-10SiO(2)-25Fe(2)O(3)-45SrO and 20B(2)O(3)-10SiO(2)-25Fe(2)O(3)-22.5Ba0-22.5SrO 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 20B(2)O(3)-10SiO(2)-25Fe(2)O(3)-22.5SrO-22.5BaO sample with simultaneous presents of Sr and Ba.