The dissolution of (50-x)Na20-xCa0-50P205 metaphosphate glasses has been investigated at pH3 in solutions containing Na+, Ca2+, Cl-, NO-3 and (P0-3) ions. Whatever the conditions, a hydrated layer develops over a surface covered with etch pits. Na+ and Cl- have no specific effect on the dissolution kinetics and mechanism. In Ca2+ containing solutions, XPS, electrophoretic mobility and 31P NMR show that Na+ is exchanged for Ca2+ in the hydrated layer, resulting in a decreased dissolution rate.
Origin
Lab Cristal Physico Du Solide, France
Journal Title
Glastech Ber Glass Sci Technol 72 5 1999 161-166
Sector
Special Glass
Class
S 1670