Mechanisms of Glass Corrosion by Aqueous Solutions

International audienceAbiotic mechanisms of chemical alteration of glass are discussed in terms of the two principal theories currently existing. The first is the traditional leached-layer model, which is based on solidstate volume interdiffusion of preferentially leached cations from the glass with hydronium species (H 3 O +) from the bulk solution. This results in the formation of a so-called cation-leached layer that is characterized by broad, diffusion-like chemical depth profiles extending from the surface to the underlying pristine glass. The second theory is relatively new and postulates that glass corrosion is controlled by coupled interfacial dissolution-reprecipitation (CIDR). This mechanism is based on coupled interfacial chemical reactions that take place within a thin fluid film at the glass interface, resulting in a reprecipitated surface layer having a very sharp interface with the pristine glass substrate. Studies from the literature are discussed and critically analyzed to illustrate the application of these two competing theories to borosilicate glass alteration in the laboratory. Finally, the main parameters influencing glass corrosion kinetics are discussed, including those that lead to decreasing rates as a function of reaction progress