Study on Chemical Durability of BAP System Glass Doped with Rare Earths

The chemical durability of BaO-Al2O3-P2O5(BAP) system glass doped 10% and 15% Sm2O3 was studied by SEM technique. The results indicated that addition of Al3+ and Sm3+ affected the water resistance ability obviously. The higher of Al3+ and Sm3+ content, the more stable of glass structure, so well as the better of water resistance ability of the Sm2O3 doping phosphate glass. Improvement of the polarize ability (Z2/r) of cations would improve acid resistance ability of rare earth phosphate glass, at the same time, overlays on the glass surface were formed by acid corrosion, which slowered the corrosion rate. In alkali medium, the corrosion mechanism was that the metal ions of phosphate long chains were hydrated, which disentangled the P-O-P bond and formed the orthophosphate units dissolved. And increase of Sm3+ ions resulted in decrease of the alkali resistance ability.