Thermal and crystallization kinetics of yttrium‐doped phosphate‐based glasses

Abstract

Yttrium‐doped glasses have been utilized for biomedical applications such as radiotherapy, especially for liver cancer treatment. In this paper, the crystallization behavior of phosphate‐based glasses doped with yttrium (in the system 45P2O5–(30 − x) Na2O–25CaO–xY2O3—where x = 0, 1, 3 and 5) have been investigated via Differential Scanning Calorimetry (DSC) using nonisothermal technique at different heating rates (5°C, 10°C, 15°C and 20°C/min). The glass compositions were characterized via EDX, XRD, Density and Molar volume analysis. The Moynihan and Kissinger methods were used for the determination of glass transition activation energy (Eg) which decreased from 192 to 118 kJ/mol (Moynihan) and 183 to 113 kJ/mol (Kissinger) with increasing yttrium oxide content. Incorporation of 0 to 5 mol% Y2O3 revealed an approximate decrease of 71 kJ/mol (Ozawa and Augis) for onset crystallization (Ex) and 26 kJ/mol (Kissinger) for crystallization peak activation energies (Ec). Avrami index (n) value analyzed via Matusita–Sakka equation suggested a one‐dimensional crystal growth for the glasses investigated. SEM analysis explored the crystalline morphologies and revealed one‐dimensional needle‐like crystals. Overall, it was found that these glass formulations remained amorphous with up to 5 mol% Y2O3 addition with further increases in Y2O3 content resulting in significant crystallization.

Yttrium doped phosphate-based glasses: structural and degradation analyses

“…The addition of Y 2 O 3 increased the durability of the glasses which was attributed to the replacement of P-O-P bonds with hydration resistant Y-O-P bonds. It should be noted that this study was limited to incorporating up to 5 mol% Y 2 O 3 content only as the glasses crystallised when further Y 2 O 3 was added in this glass system [44]. Future studies will focus on manufacturing higher yttrium containing phosphate-based glasses by exploring alternate manufacturing processes.…”

“…The crystallisation kinetics and ionic conductivity of yttrium phosphate glasses have been reported [41][42][43][44]. Petra et al studied crystallisation kinetics of erbiumdoped yttrium phosphate glasses for scintillation applications [45] by exploring the effect of particle sizes in both powder and bulk samples.…”