Investigating the effect of heat treatment temperature on the crystallization of magnetic phases in the ۲۰〖SiO〗_۲-۵۰FeO-۱۰CaO glass ceramic System

In treatment methods, there is no single mechanism for cancer treatment, and in practice, a combination of different methods is used to treat cancer. Methods such as chemotherapy (to treat cancer cells with chemicals/drugs), radiotherapy (to treat cancer cells with radiation) and hyperthermia (to treat cancer cells with heat). In the meantime, hyperthermia has received much attention due to less complications. The heat required to destroy cancer cells in this method is obtained through the hysteresis losses of thermal seeds with magnetic phase. In this study, the effect of different heat treatment temperatures on the crystallization and oxidation of magnetic phases has been investigated. For this purpose, ۲۰SiO_۲-۵۰FeO-۱۰CaO glass ceramic was synthesized by sol-gel method. precursers used for this study, tetra ethyl ortho-silicate (SiC_۸ H_۲۰ O_۴), calcium nitrate tetrahydrate (Ca (NO₃) ₂.۴H₂O), sodium nitrate (NaNO₃) and iron nitrate (Fe (NO₃) ₃) were selected. Distilled water and ethanol were selected as solvents and the precursers ratio was ۵: ۱. The synthesis temperature was ۲۵℃ and the aging time was ۲۴ hours. The synthesized glasses were heat treated at different temperatures. According to the obtained results, the magnetite phase is stable up to ۳۶۰°C and oxidizes to maghemite when the temperature increases to ۴۴۰℃. The maghemite phase is also oxidized to hematite and by increasing the temperature to temperatures higher than ۵۰۰℃, and with a further increase in temperature, the amount of this transformation increases and leads to a decrease in the magnetic properties of the glass-ceramic sample.

Keywords:

Heat Treatment , Magnetic Phase , Glass Ceramic , Hematite , Maghemite.