Viscosity and kinetic fragility of alkaline earth zinc phosphate glasses
Viscosity and kinetic fragility of alkaline earth zinc phosphate glasses
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DOI：
10.1016/j.jnoncrysol.2012.03.031
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发表时间：
2012-07
影响因子：
3.5
通讯作者：
S. Striepe;J. Deubener
中科院分区：
文献类型：
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作者：
S. Striepe;J. Deubener
用粘度法和差示扫描量热法（DSC）测定了20 MO-30 ZnO-50 P2 O 5（M=Ba，Sr，Ca，Mg）碱土磷酸锌熔体的动力学脆性指数m和F1/2以及玻璃化转变温度Tg。分别进行了光束弯曲实验和同心圆柱实验来测量玻璃化转变温度以上和接近液相线温度范围内的流动阻力。通过玻璃化转变的DSC运行的不同上扫描速率被用来关联假想温度与动力学脆性的变化。两种方法均表明，玻璃化转变温度与M的大小呈负相关，动力学脆性与M的大小呈正相关。金属阳离子混合（M+Zn）导致Tg与线性的负偏差，而如果用平均电荷距离比进行缩放，则交换M导致Tg与线性相关。虚构的温度方法高估的比例高达1.9的m的组成依赖性。
Kinetic fragility indices m and F1/2as well as glass transition temperature Tgof alkaline earth zinc phosphate melts of molar composition 20 MO–30 ZnO–50 P2O5(with M=Ba, Sr, Ca, Mg) were determined using viscometry and differential scanning calorimetry (DSC). Beam bending and concentric cylinder experiments were performed to measure the flow resistance in temperature ranges above glass transition and close to liquidus, respectively. Different upscan rates of DSC runs through the glass transition were used to correlate changes of the fictive temperature with kinetic fragility. Both methods revealed that glass transition temperature correlates negatively and kinetic fragility positively with the size of M. Metal cation mixing (M+Zn) led to a negative deviation from linearity for Tg, while exchanging M resulted in a linear dependence of Tg, if scaled with averaged charge-to-distance ratio. The fictive temperature method overestimated the compositional dependence of m by a ratio up to 1.9.