Ion-Exchange Formation of Magnetic Iron-Containing Glass with a Porous Structure

Abstract

The ion-exchange interaction of potassium iron-silicate glass with lithium nitrate melt is studied. It is established that a magnetic matrix with polymodal pore size distribution in the range of 1 nm to 10 μm is formed. No diffusion kinetics are detected in the interaction of glass with the salt melts. It is determined that the thermal history of the glass affects the composition of the phases crystallizing in it, as well as the Fe2+-to-Fe3+ ratio and their coordination. According to the Mossbauer spectroscopy data in the annealed glass, Fe3+ and Fe2+ are tetrahedrally coordinated, while Fe3+ and Fe2+ are present in the octahedral coordination and Fe3O4 in the quenched glass. It is determined that the initial glass 20K2O · 12.5FeO · 12.5Fe2O3 · 55SiO2, mol %, is paramagnetic. The porous matrix of the glass (20Li2O · 12.5FeO · 12.5Fe2O3 · 55SiO2, mol %) obtained as a result of the ion-exchange treatment of the glass in the LiNO3 melt is characterized by the specific saturation magnetization of 1.8 G cm3 g–1 and the coercive force of ≈ 80 Oe at room temperature. A composition material based on the magnetic glass matrix and ferroelectric in the pore space of the glass is produced.