UNDER WHAT CONDITIONS CAN A GLASS BE FORMED
UNDER WHAT CONDITIONS CAN A GLASS BE FORMED
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DOI：
10.1080/00107516908204405
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发表时间：
1969-01-01
影响因子：
2
通讯作者：
TURNBULL, D
中科院分区：
文献类型：
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作者：
TURNBULL, D
一般来说，物质在结晶状态下比在玻璃状态下更稳定。因此，要形成玻璃，必须绕过结晶。在一定条件下，许多物质的熔体可以冷却到玻璃状态。给定材料的熔体是否形成玻璃主要取决于一系列因素，这些因素在实验室中可以在一定程度上确定，即冷却速率，t，液体体积，v]和种子密度，p取决于一组材料常数：还原的晶体-液体界面张力，α，晶体表面受体位点的分数，f，和还原的玻璃温度，Trg。- ttrg越大，arev越小，玻璃化倾向越大。通过将材料从溶液冷凝到远低于其玻璃温度的表面的技术，以玻璃状或“非晶固体”形式制备的物质的数量和种类已经大大增加。根据键的类型，即共价键、离子键、金属键、范德华键或氢键，每种材料中都至少有一些成玻璃体。然而，是否每一种物质都能被制成玻璃状还没有确定。
Generally substances are more stable in a crystalline than in a glassy state. Therefore, to form a glass, crystallization must be bypassed. Under certain conditions, the melts of many substances can be cooled to the glass state. Whether or not the melt of a given material forms a glass is determined principally by a set of factors which can be specified to some extent in the laboratory, namely, the cooling rate, -T, the liquid volume,v], and the seed density,psand upon a set of materials constants: the reduced crystal–liquid interfacial tension, α the fraction,f, of acceptor sites in the crystal surface, and the reduced glass temperature,Trg. The glass-forming tendency will be greater the larger are -TandTrgand the smaller arev].ps, andf. The number and variety of substances which have been prepared in a glassy or ‘amorphous solid’ form have been greatly increased with techniques in which the material is condensed from solution on to a surface held well below its glass temperature. There are at least some glass formers in every category of material, according to bond type, i.e. covalent, ionic, metallic, van der Waals or hydrogen. However, it is not established whether or not every substance can be put into a glass form.