Effects of nitrogen and fluorine on crystallisation of Ca–Si–Al–O–N–F glasses
Effects of nitrogen and fluorine on crystallisation of Ca–Si–Al–O–N–F glasses
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DOI：
10.1016/j.jeurceramsoc.2011.10.026
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发表时间：
2012-04
影响因子：
5.7
通讯作者：
A. Hanifi;Annaik Genson;W. Redington;M. Pomeroy;S. Hampshire
中科院分区：
文献类型：
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作者：
A. Hanifi;Annaik Genson;W. Redington;M. Pomeroy;S. Hampshire
本文研究了Ca-Si-Al-O-N-F系统中氮、氟取代对新一代氟氧氮化物玻璃析晶的影响。玻璃在Tg+50°C的成核温度下成核5小时，并在由差热分析确定的最大结晶温度（900-1050°C，取决于玻璃组成）下结晶10小时。对于氧化物玻璃，结晶导致硅灰石（CaSiO 3）、钙黄长石（Ca 2Al 2SiO 7）和钙长石（CaAl 2Si 2 O 8）沿着少量残余玻璃的形成。用于氟氧化物玻璃的结晶（0当量%当氟含量为20 equiv.%时，玻璃中的钙铝黄长石晶相逐渐减少，而枪晶石（Ca_4Si_2O_7F_2）晶相逐渐减少，在不同氟含量下，钙铝黄长石始终是主要晶相。在恒定的氟含量（5当量%）下，氮含量的增加有利于钙铝黄长石而不是钙长石或硅灰石的形成，这表明该相能够将N容纳到其晶体结构中。虽然在钙铝黄长石结构中可以假定少量的氮取代氧，但是玻璃-陶瓷中的残余玻璃预期是非常富N的。在性能方面，硬度被证明是更敏感的微观结构，相形态和晶体尺寸的变化相比，弹性模量，这是相关的组成相存在的量。
The effect of nitrogen and fluorine substitution on the crystallisation of a new generation of oxyfluoronitride glasses in the Ca–Si–Al–O–N–F system has been studied. Glasses were nucleated for 5h at the nucleation temperature of Tg+50°C and crystallised for 10h at the maximum crystallisation temperature (900–1050°C depending on the glass composition) determined from differential thermal analysis. For the oxide glass, crystallisation results in formation of wollastonite (CaSiO3), gehlenite (Ca2Al2SiO7) and anorthite (CaAl2Si2O8) along with a small amount of residual glass. For crystallisation of oxyfluoride glasses (0equiv.% N), when fluorine content increases, cuspidine (Ca4Si2O7F2) is the major crystalline phase at the expense of gehlenite while in oxyfluoronitride glasses containing 20equiv.% N, gehlenite is always the dominant crystalline phase at different fluorine contents. At constant fluorine content (5equiv.%), an increase in nitrogen content favours the formation of gehlenite rather than anorthite or wollastonite suggesting that this phase may be able to accommodate N into its crystal structure. While a small amount of nitrogen substitution for oxygen can be assumed in the gehlenite structure, the residual glass in the glass-ceramic is expected to be very N-rich. In terms of properties, hardness is shown to be more sensitive to changes in microstructure, phase morphology and crystal size compared with elastic modulus which is related to the amounts of constituent phases present.