Cation concentration profiles in float glass surfaces during corrosion in aqueous solutions

Abstract

The chemical composition of the thin surface layer of float glass is not homogeneous with respect to the concentration of some cations. This inhomogeneous cation distribution significantly changes if the glass surface comes into contact with aqueous Solutions. Using ESCA significant changes in the distribution of magnesium and sodium cations were found on the " top " surface of float glass in static corrosion environment. The magnesium concentration increases in the th in surface layer, while sodium concentration decreases almost to zero. The relative amounts of calcium, Silicon and oxygen appear to be nearly the same both in the original and the corroded surface layer. The change of magnesium and sodium concentrations as well as an electron micrograph of the glass surface indicate damage and hydration of the " top " surface layer of float glass. The distribution of the Clements does not show any significant change if corrosion proceeds in Streaming water. Consequently, total dissolution of the basic glass network built by Silicon and oxygen atoms appears to be the fundamental process in this case.