Contribution of some divalent oxides replacing Li2O to crystallization characteristics and properties of magnetic glass–ceramics based on Li2O–Fe2O3–Al2O3–SiO2

Abstract

Magnetic glass–ceramics based on the Li2O–Fe2O3–Al2O3–SiO2 glass system, were prepared through controlled heat treatment regimes. The effect of MO/Li2O replacements (MO=MgO, MnO, ZnO, CdO) on the crystallization process, physical and magnetic properties of the glasses and glass–ceramics were investigated. The crystalline phases formed in the glass–ceramic were lithium metasilicate (Li2SiO3), β-quartz solid solution (ss) (LiAlSi2O6), lithium ferrite (LiFe5O8), Magnesioferrite (MgFe2O4), Jacobsite (MnFe2O4), Franklinite (ZnFe2O4), lithium zinc orthosilicate (γ-Li2ZnSiO4) and lithium ferrite solid solution Li(Fe,Cd)5O8. The density of the prepared glass samples ranged from 2.69 to 2.88g/cm3, whereas the corresponding crystalline materials had a density between 2.77 to 2.95g/cm3. The microhardness of the glass samples ranged from 4665MPa to 5586MPa and increased to a range of 6268–7042MPa after crystallization. The saturation magnetization (Ms), remanence magnetization (Mr), and coercivity (Hc) of the glass–ceramics varied from 0.83 to 8.24emu/g, 0.11 to 0.97emu/g and 112 to 211G, respectively. The formation of different MFe2O4 spinel ferrite magnetic phases instead of LiFe5O8 led to a greatly enhanced saturation magnetization of the glass–ceramics. Possible use of the prepared glass–ceramics may be realized in microwave and magnetic recording applications as well as in tumors therapy.