The mechanism of borosilicate glass corrosion revisited
The mechanism of borosilicate glass corrosion revisited
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DOI：
10.1016/j.gca.2015.02.039
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发表时间：
2015-06-01
影响因子：
5
通讯作者：
Nemchin, Alexander A.
中科院分区：
文献类型：
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作者：
Geisler, Thorsten;Nagel, Thorsten;Nemchin, Alexander A.
目前公认的描述硼硅酸盐玻璃水腐蚀的机理模型基于扩散控制的水解、水合、离子交换反应以及随后水解玻璃网络的再缩合，留下残留的水合玻璃或凝胶层。在这里，我们报告了三元钠硼硅酸盐玻璃的新型氧和硅同位素示踪剂实验的结果，该结果可以通过涉及玻璃同成分溶解的过程得到更好的解释，该过程在空间和时间上与向内移动的反应界面处无定形二氧化硅层的沉淀和生长耦合。这一过程在热力学上由玻璃和无定形二氧化硅之间的溶解度差异驱动，并在动力学上由反应前沿的玻璃溶解反应控制，而反应前沿又由水和溶质元素通过不断增长的腐蚀区的传输控制。了解这些反应的耦合是了解在古代玻璃的自然腐蚀区域中观察到的层状或更复杂的结构和化学模式的形成的关键。我们建议还必须考虑这些耦合过程，以真实地模拟硅酸盐玻璃在水性环境中的长期性能。 (C) 2015 Elsevier Ltd. 保留所有权利。
Currently accepted mechanistic models describing aqueous corrosion of borosilicate glasses are based on diffusion-controlled hydrolysis, hydration, ion exchange reactions, and subsequent re-condensation of the hydrolyzed glass network, leaving behind a residual hydrated glass or gel layer. Here, we report results of novel oxygen and silicon isotope tracer experiments with ternary Na borosilicate glasses that can be better explained by a process that involves the congruent dissolution of the glass, which is spatially and temporally coupled to the precipitation and growth of an amorphous silica layer at an inwardly moving reaction interface. Such a process is thermodynamically driven by the solubility difference between the glass and amorphous silica, and kinetically controlled by glass dissolution reactions at the reaction front, which, in turn, are controlled by the transport of water and solute elements through the growing corrosion zone. Understanding the coupling of these reactions is the key to understand the formation of laminar or more complex structural and chemical patterns observed in natural corrosion zones of ancient glasses. We suggest that these coupled processes also have to be considered to realistically model the long-term performance of silicate glasses in aqueous environments. (C) 2015 Elsevier Ltd. All rights reserved.