Dissolution of lanthanide alumino-silicate oxynitride glasses

The aqueous corrosion behavior of lanthanide aluminosilicate glasses has been studied under static conditions (T = 96 degrees C, duration = 1 and 3 months, glass surface area/leachate volume, S/V= 0.3 cm(-1)) by means of solution and solid analyses. It was found that these glasses exhibit a high chemical durability. The influence of yttrium, magnesium and nitrogen, which are supposed to improve the mechanical properties, on the chemical durability, has been investigated. After a one-month experiment, lanthanum and yttrium releases were found to be about 10(-7) mol l(-1), while silicon and aluminum releases were about 10(-5) mol l(-1). Yttrium seems to improve the chemical durability. The presence of nitrogen does not seem to modify the glass constituents releases, but seems to improve the surface state of the altered glass. XPS experiments reveal that lanthanum and yttrium are more concentrated near the surface (20-30 Angstrom) of the glass after the leaching test. (C) 2000 Elsevier Science B.V. All rights reserved.