Intrinsic phase separation in low-temperature quenched arsenic trisulfide glass
Intrinsic phase separation in low-temperature quenched arsenic trisulfide glass
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DOI：
10.1016/j.jnoncrysol.2015.09.019
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发表时间：
2015-12
影响因子：
3.5
通讯作者：
O. Shpotyuk;A. Kovalskiy;J. Trimble;M. Vlcek;Y. Shpotyuk;S. Kozyukhin
中科院分区：
文献类型：
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作者：
O. Shpotyuk;A. Kovalskiy;J. Trimble;M. Vlcek;Y. Shpotyuk;S. Kozyukhin
利用拉曼散射光谱研究了不同均化路线下三硫化二砷玻璃本征相分离的本质，结果表明，采用常规熔融淬火路线制备的三硫化二砷玻璃会发生本质相分离，这取决于密封在真空安瓿中的元素成分的均化。在450-550 ℃低温均匀化条件下，由于液态S在固态As中的溶解度有限，产生化学作用，导致结构上本征的富As相和富S相，分别具有高含量的同质原子As-As和S-S键，哪些是“错误的”从As 2S 3化学计量的角度来看，该过程可以通过更快速的加热和更大量的初始元素来基本上促进。用于合成的成分。在此本质上分解的熔体（如持续2天，在摇摆炉）的长时间均质化，这些产品被部分分离，使主要的玻璃相富集在雄黄和二无定形物型分子的形式，孤立的As-As键在玻璃网络和挥发的富S相，它冷凝在安瓿的壁上。如果这种熔体在500 °C下加热6小时而仅摇动2小时时不充分均匀化，则在最终玻璃中保持配位无序。这使得挥发的富S相不会形成，并且所有分解产物都稳定在玻璃态，作为准四面体单元和补偿同原子As-As键。
The nature of intrinsic phase separation initiated under different homogenization routes is studied in arsenic trisulfide As2S3glass using Raman scattering spectroscopy.It is shown that As2S3glass prepared within conventional melt-quenching route is subjected to essential phase separation dependent on the homogenization of elemental constituents sealed in evacuated ampoules. Under condition of low-temperature homogenization at 450–550 °С, chemical interaction due to limited solubility of liquid S in solid As results in structurally intrinsic As- and S-rich phases with high content of homoatomic As–As and S–S bonds, respectively, which are “wrong” from the point of As2S3stoichiometry This process can be essentially facilitated with more rapid heating and greater amount of initial elemental ingredients taken for synthesis. During prolonged homogenization of this intrinsically-decomposed melt (such as lasting 2 days in a rocking furnace), these products are partially separated giving main glassy phase enriched on As in the form of realgar- and dimorphite-type molecules, isolated As–As bonds in a glassy network and volatilized S-rich phase, which condenses on the walls of ampoules. If such melt is insufficiently homogenized as under 6-h heating at 500 °C with only 2-h rocking, the coordination disordering is maintained in the ultimate glass. This provides that volatilized S-rich phase does not form, and all decomposition products are stabilized in glassy state as quasi-tetrahedral units and compensating homoatomic As–As bonds.