High‐alumina containing high‐level waste (HLW) will be vitrified at the Waste Treatment Plant at the Hanford Site. The resulting glasses, high in alumina, will have distinct composition‐structure‐property (C‐S‐P) relationships compared to previously studied HLW glasses. These C‐S‐P relationships determine the processability and product durability of glasses and therefore must be understood. The main purpose of this study is to understand the detailed structural changes caused by Al:Si and (Al + Na):Si substitutions in a simplified nuclear waste model glass (ISG, international simple glass) by combining experimental structural characterizations and molecular dynamics (MD) simulations. The structures of these two series of glasses were characterized by neutron total scattering and ²⁷Al, ²³Na, ²⁹Si, and ¹¹B solid‐state nuclear magnetic resonance (NMR) spectroscopy. Additionally, MD simulations were used to generate atomistic structural models of the borosilicate glasses and simulation results were validated by the experimental structural data. Short‐range (eg, bond distance, coordination number, etc) and medium‐range (eg, oxygen speciation, network connectivity, polyhedral linkages) structural features of the borosilicate glasses were systematically investigated as a function of the degree of substitution. The results show that bond distance and coordination number of the cation‐oxygen pairs are relatively insensitive to Al:Si and (Al + Na):Si substitutions with the exception of the B‐O pair. Additionally, the Al:Si substitution results in an increase in tri‐bridging oxygen species, whereas (Al + Na):Si substitution creates nonbridging oxygen species. Charge compensator preferences were found for Si‐[NBO] (Na⁺), ^[3]B‐[NBO] (Na⁺), ^[4]B (mostly Ca²⁺), ^[4]Al (nearly equally split Na⁺ and Ca²⁺), and ^[6]Zr (mostly Ca²⁺). The network former‐BO‐network former linkages preferences were also tabulated; Si‐O‐Al and Al‐O‐Al were preferred at the expense of lower Si‐O‐^[3]B and ^[3]B‐O‐^[3]B linkages. These results provide insights on the structural origins of property changes such as glass‐transition temperature caused by the substitutions, providing a basis for future improvements of theoretical and computer simulation models.

中文翻译：

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Al：Si和（Al + Na）：Si比对国际简易玻璃性能的影响，第二部分：结构

包含高氧化铝的高放废物（HLW）将在汉福德工厂的废物处理厂进行玻璃化处理。与先前研究的HLW玻璃相比，所得的高氧化铝玻璃将具有独特的成分-结构-性质（C-S-P）关系。这些C‐P‐P关系决定了眼镜的可加工性和产品耐用性，因此必须了解。这项研究的主要目的是通过结合实验结构特征和分子动力学来了解简化的核废料模型玻璃（ISG，国际简单玻璃）中由Al：Si和（Al + Na）：Si取代引起的详细结构变化（ MD）模拟。这两个系列玻璃的结构以中子总散射和²⁷ Al，²³Na，²⁹ Si和¹¹B固态核磁共振（NMR）光谱。另外，使用MD模拟生成硼硅玻璃的原子结构模型，并通过实验结构数据验证了模拟结果。根据取代度的函数，系统地研究了硼硅酸盐玻璃的短程（例如键距，配位数等）和中程（例如氧形态，网络连接性，多面键）的结构特征。结果表明，除了B-O对之外，阳离子-氧对的键距和配位数对Al：Si和（Al + Na）：Si取代相对不敏感。此外，Al：Si取代导致三桥联氧物种增加，而（Al + Na）：硅取代产生非桥连的氧物种。发现Si- [NBO]（Na⁺），^[3] B- [NBO]（Na ⁺），^[4] B（主要为Ca 2 ⁺），^[4] Al（几乎等分的Na ⁺和Ca ²⁺）和^[6] Zr（主要是Ca ²⁺）。网络前BO前网络前链接首选项也已制成表格；首选Si-O-Al和Al-O-Al，但要以较低的Si-O- ^[3] B和^[3] B-O- ^[3] B键为代价。这些结果提供了关于特性变化的结构起源的见解，例如由替代引起的玻璃化转变温度，为理论和计算机仿真模型的未来改进提供了基础。