Hardness of oxynitride glasses: topological origin.
Hardness of oxynitride glasses: topological origin.
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DOI：
10.1021/jp512235t
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发表时间：
2015-03
期刊：
影响因子：
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通讯作者：
G. Paraschiv;Sinue Gomez;J. Mauro;L. Wondraczek;Y. Yue;M. Smedskjaer
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文献类型：
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作者：
G. Paraschiv;Sinue Gomez;J. Mauro;L. Wondraczek;Y. Yue;M. Smedskjaer
氧氮化物玻璃是一种混合阴离子体系，其中2重配位的氧原子被3重配位的氮原子部分取代。这种所谓的氮化过程引入了额外的键，从而约束和压实了玻璃网络，并因此改变了玻璃硬度。为了探索硬度如何以及为什么随着氮化程度而变化，我们已经推导出了一个拓扑模型的氮氧玻璃硬度与温度相关的约束理论，通过该模型可以预测玻璃硬度与氮含量的比例。基于氮原子取代氧原子是由于键弯曲和键角约束的数目（n）增加而导致硬度增加的假设，已经推导出线性模型。事实证明，该模型与实验观察一致，即，对于宽范围的玻璃组合物，观察到硬度随氮含量变化的近似正线性趋势。因此，拓扑模型可用于设计具有目标硬度值的新的氧氮化物玻璃组合物。
Oxynitride glasses are mixed-anion systems, in which the 2-fold coordinated oxygen atoms have been partially substituted by 3-fold coordinated nitrogen atoms. This so-called nitridation process introduces additional bonds and thereby constrains and compacts the glass network and consequently alters the glass hardness. To explore how and why hardness varies with the degree of nitridation, we have derived a topological model of oxynitride glass hardness using temperature-dependent constraint theory, by which the scaling of glass hardness with nitrogen content can be predicted. A linear model has been derived based on the assumption that the substitution of oxygen atoms with nitrogen atoms is responsible for the hardness increase due to the increase in the number (n) of bond-bending and bond-angular constraints. It turns out that the model agrees with the experimental observation, i.e., an approximate positive linear trend of the hardness change with nitrogen content is observed for a wide range of glass compositions. The topological model may thus be useful for designing new oxynitride glass compositions with targeted hardness values.