New high nickel-containing glass-ceramics based on Li2O–CaO–SiO2 eutectic (954 °C) system for magnetic applications

In the present work, the authors partially introduce NiO in the place of CaO into the 23.5Li ₂O-11.5CaO-55SiO ₂ eutectic (954 ± 4 °C) glass system to study the effect of composition modification on crystallization characteristics and magnetic behavior. Also, the effects of NiO contents on density, microhardness and chemical durability were examined. Lithium-based silicate glasses were prepared by a conventional melt-quenching technique, followed by a two-step heat-treatment to prepare glass-ceramics. The DTA results indicated that Tg of the synthesised glasses decreased with the increase of NiO content. The XRD indicated that Li-disilicate and their solid solution (Li,Ni) ₂Si ₂O ₅, Li ₂Ca ₃Si ₆O ₁₆ and quartz phases were crystallized, in addition to Niopside-CaNiSi ₂O ₆ and Ni ₂SiO ₄ phases. Adding NiO instead of CaO in the prepared glass-ceramics led to the formation of a dense structure with density values rising from 2.48 to 2.62 g/cm ³ and greatly improved in hardness number from 4410 to 5311 MPa. The chemical durability has also improved dramatically. The examined glass-ceramics had excellent magnetic properties with saturation magnetization (0.053 –0.44 emu/g), remanence magnetization (1.7–5.4 emu/g), and coercivity force (50–157 G).The study shows glass-ceramic with excellent properties that have attracted considerable attention in electronic devices, wear-resistance uses, and biomedicine applications.