Chemical stability of ZrF4- and AlF3-based heavy metal fluoride glasses in water

摘要

Glasses of the compositions 50ZrF(4)-33BaF(2)-10YF(3)-7AlF(3) and 40AlF(3)-12BaF(2)-22CaF(2)-16YF(3)-10SrF(2) (mol%), respectively, were corroded in H2O for different times at 20-80 degreesC. The cationic species Zr. Al, Ba, Y, etc, were measured by secondary neutral mass spectrometry, whereas H was measured by nuclear reaction analysis. In the case of the ZrF4-based glass the reaction depths follow at 20 degreesC a dependence proportional to t, the attack time. This dependence changed with temperature as the roott at 80 degreesC. The H reaction profiles fit well into this scheme. In the case of the AlF3-based glass also a roott-dependence is obtained at 80 degreesC. Whereas the reaction layer peels off for the ZrF4-based glass for longer times (>1 h), it is relatively stable on the AlF3-based glass and protects it against further attack. The AlF3-based glass is about 10 times more stable in water than the ZrF4-based glass. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 11]