Crystallization and magnetic properties of a 10Li2O–9MnO2–16Fe2O3–25CaO–5P2O5–35SiO2 glass

Abstract

The crystallization behavior and magnetic properties of 10Li2O–9MnO2–16Fe2O3–25CaO–5P2O5–35SiO2 (10LFS) glass have been studied using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) to observe the crystallization behavior and a superconducting quantum interference device (SQUID) for measurements of the magnetic properties. The DTA shows that the 10LFS glass has one broad exothermic peak at approximately 674 °C and one sharp (the highest) exothermic peak at 764 °C. When the 10LFS glass crystallized at 850 °C for 4 h, the crystalline phases identified by XRD were lithium silicate (Li2SiO3), β-wollastonite (β-CaSiO3), lithium orthophosphate (Li3PO4), magnetite (FeFe2O4) and triphylite (Li(Mn0.5Fe0.5)PO4). The SEM surface analysis revealed that the β-wollastonite and lithium silicate have a lath morphology. The TEM microstructure examination showed that the largest FeFe2O3 particles have a size of approximately 0.3 μm. When the 10LFS glass was heat treated at 850 °C for 16 h and a magnetic field of 1000 Oe was applied, a very small remnant magnetic induction of 0.01 emu g−1 and a coercive force of 50 Oe were obtained, which revealed an inverse spinel structure.