Morphological instability of aqueous dissolution of silicate glasses and minerals

Understanding of aqueous dissolution of silicate glasses and minerals is of great importance to both Earth and materials sciences. Silicate dissolution exhibits complex temporal evolution and rich pattern formations. Recently, we showed how observed complexity could emerge from a simple self-organizational mechanism: dissolution of the silica framework in a material could be catalyzed by the cations released from the reaction itself. This mechanism enables us to systematically predict many key features of a silicate dissolution process including the occurrence of a sharp corrosion front (vs. a leached surface layer), oscillatory dissolution and multiple stages of the alteration process (e.g., an alteration rate resumption at a late stage of glass dissolution). Here, through a linear stability analysis, we show that the same mechanism can also lead to morphological instability of an alteration front, which, in combination with oscillatory dissolution, can potentially lead to a whole suite of patterning phenomena, as observed on archaeological glass samples as well as in laboratory experiments, including wavy dissolution fronts, growth rings, incoherent bandings of alteration products, and corrosion pitting. The result thus further demonstrates the importance of the proposed self-accelerating mechanism in silicate material degradation