Contribution of some transition metal oxides to crystallization and electro-thermal properties of glass-ceramics

Abstract Lithium di-silicate (LS2) glass-ceramics modified with copper oxide using the formula: 34.83Li2O–xCuO–(65.17-x)SiO2 (where; x = 1, 2, 4 and 6 mol%) were prepared by melt-quenching followed by controlling heat-treatment. 6 mol% of MnO or Fe2O3 transition metal oxides was added instead of SiO2 in the high CuO-content composition. The effect of the transition cations on phase formation, microstructure, density, thermal expansion, and electrical conductivity was investigated as a function of the controlled crystallization. Results show that up to 4 mol%, Cu+2 was hosted in stable Li2Si2O5 structure. This enhanced the crystal formation, including Li2Si2O5 and its solid solution (ss), Li2SiO3, Li2Cu5(Si2O7)2, CuMn6SiO12, LiFeSi2O6 (ss), and the orthosilicate Li2FeSiO4 (ss). The prepared materials had different density values ranged from 2.35 to 2.79 g/cm3 for glass and varied from 2.43 to 3.15 g/cm3 for glass–ceramics, whereas the α-values of glass-ceramics ranged in the 95–165 × 10−7/°C. The progress of electrical properties in glass-ceramics, as a function of composition, was studied. It was markedly improved by adding different transition cations especially, Fe+3. The study reveals that the incorporation of transition metal ions in LS2 composition has a positive effect on the physical-chemical properties of the prepared glass-ceramics. Therefore, it constitutes to prepare future glass-ceramic applications as hermetic seals of metals as well solid electrolyte materials.