Effect of heat treatment on the composition of surface layers in lithium silicate glass exposed to acid and salt solutions

• Published in: Glass physics and chemistry Vol. 28; no. 2; pp. 103 - 111
• Main Authors: BELYUSTIN, A. A, IVANOVSKAYA, I. S, BARANOVA, G. V
• Format: Journal Article
• Language: English
• Published: Moscow Kluwer/Plenum 01.03.2002; New York, NY Nauka/Interperiodica; Springer Nature B.V
• Subjects: Acids; Concentration (composition); Crystallization; Glass; Hafnium; Heat treating; Heat treatment; Leaching; Lithium; Surface layer
• ISSN: 1087-6596; 1608-313X
• DOI: 10.1023/A:1015381631617

The concentration distribution of lithium ions in the surface layers of the 27Li sub(2)O-73SiO sub(2) (mol %) glass samples subjected and unsubjected to heat treatment under different conditions after exposure to 0.1 M HCl + y M LiCl (y = 0, 1.0, 5.0, and 10) solutions is studied by the HF-sectioning technique. It is found that the specific ("molded") layer formed on the glass surface upon pouring of a glass melt into a cooled mold affects the leaching processes in both the initial and phase-separated glasses. In the absence of the molded layer, the leaching rate of the initial glass in the acid is lower than that of the phase-separated glass and higher than that of the crystallized glass. The leaching rate of the phase-separated and crystallized samples in the acid with an salt additive is higher than that of the initial salt. Chlorine ions in the acid solution bring about a weakening of the silicon-oxygen network. The profiles of the dissolution rate of glass in a 1% HF solution correlate with the concentration profiles of lithium.