Title

Mechanisms for Alkali Leaching in Mixed-Na-K Silicate Glasses

Abstract

The kinetics of alkali removal from (1-X) Na2O·XK2O·3SiO2 glasses were studied using pH stat titration techniques, solution analyses, and elemental depth profiling by Rutherford backscattering spectrometry and elastic recoil detection. In the first stage of leaching (t1/2 kinetics), the interdiffusion coefficients measured for the exchange of alkali cations by H3O+ are orders of magnitude greater than the alkali diffusion coefficients in bulk glass and show no evidence of the mixed-alkali effect. At longer times, the rate of alkali removal becomes constant with time, but selective alkali leaching is still observed rather than uniform dissolution. These results support a model where the rate determining step for alkali leaching is the rate at which molecular water diffuses into the glass.

Department(s)

Materials Science and Engineering

Keywords and Phrases

GLASS

International Standard Serial Number (ISSN)

0022-3093; 1873-4812

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1983 Elsevier, All rights reserved.

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