Abstract Rare ancient glasses have complex, multi-scale structures requiring more sophisticated and non-destructive pore characterisation techniques than usual. Homotattic patch models for nitrogen adsorption gave better fits to the isotherm data, more accurate void space descriptors, and also greater understanding of the underlying physical factors affecting adsorption, than standard BET. These homotattic patch models revealed the critical role of iron impurities in determining adsorption behaviour. Non-destructive sodium-23 NMR relaxometry validated the homotattic patch model for some natron glasses, and, in turn, was validated using multiple quantum magic-angle spinning (MQMAS) 23Na NMR. X-ray tomography images of the glasses showed the presence of large macroporous bubbles, while FEG-SEM revealed nanopores within the glass matrix. A newly-developed, gas overcondensation technique, suitable for small amounts of low porosity material, assessed the inter-relationship between the disparate levels in this hierarchical porosity. This technique demonstrated that the nanoporosity did not form a ‘corona’ around the bubbles, due to leaching from the glass, as initially supposed from tomography data, but was completely disconnected, and, thus, is probably associated with glass alkalinity. Gas overcondensation is demonstrated as a non-destructive alternative to mercury porosimetry for probing multi-scale porosity in rare artefacts.

中文翻译：

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使用气体过冷凝、X 射线断层扫描和固态核磁共振探测古代玻璃的结构和化学异质性

摘要 稀有的古代玻璃具有复杂的多尺度结构，需要比平常更复杂和非破坏性的孔隙表征技术。与标准 BET 相比，氮吸附的同向贴片模型更适合等温线数据、更准确的空隙空间描述符，以及对影响吸附的潜在物理因素的更深入理解。这些同向斑块模型揭示了铁杂质在决定吸附行为中的关键作用。非破坏性钠 23 NMR 弛豫测量验证了一些 natron 玻璃的同向斑块模型，并反过来使用多量子魔角旋转 (MQMAS) 23Na NMR 进行了验证。玻璃的 X 射线断层扫描图像显示存在大的大孔气泡，而 FEG-SEM 显示玻璃基质中存在纳米孔。一种适用于少量低孔隙度材料的新开发的气体过冷凝技术评估了这种分级孔隙度中不同水平之间的相互关系。这项技术表明，纳米孔隙没有在气泡周围形成“电晕”，这是由于从玻璃中浸出，正如最初从断层扫描数据所推测的那样，但完全断开，因此，可能与玻璃碱度有关。气体过冷凝被证明是用于探测稀有文物中多尺度孔隙度的汞孔隙率测定法的非破坏性替代方法。这项技术表明，纳米孔隙没有在气泡周围形成“电晕”，这是由于从玻璃中浸出，正如最初从断层扫描数据所推测的那样，但完全断开，因此，可能与玻璃碱度有关。气体过冷凝被证明是用于探测稀有文物中多尺度孔隙度的汞孔隙率测定法的非破坏性替代方法。这项技术表明，纳米孔隙没有在气泡周围形成“电晕”，这是由于从玻璃中浸出，正如最初从断层扫描数据所推测的那样，但完全断开，因此，可能与玻璃碱度有关。气体过冷凝被证明是用于探测稀有文物中多尺度孔隙度的汞孔隙率测定法的非破坏性替代方法。