Redox dynamics in the high-temperature float processing of glasses. I. Reaction between undoped and iron-doped borosilicate glassmelts and a gold–tin alloy

• Published in: Journal of non-crystalline solids 1999-07, Vol.249 (2), p.210-227
• Main Authors: Cook, Glen B., Cooper, Reid F.
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Exact sciences and technology; Glasses; Manufacture
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/S0022-3093(99)00312-9

X-ray emission and Rutherford backscattering spectroscopies were used to characterize the dynamic chemical response in two borosilicate glassmelts (both Pyrex™ composition, one with 0.08 at.% Fe added) reacted with a Au-30Sn liquid alloy. Reactions were done at temperatures of 1250–1350°C for 30 min under a reducing atmosphere. Because of the metal alloy design and the glass structure, the chemical diffusion response shows less Sn incorporation into the glassmelt than in conventional commercial soda-lime float; the addition of Fe 3+ acts decisively to reduce the kinetics of Sn penetration. The results indicate a cation-diffusion-limited reduction reaction as the dominant kinetic mechanism working towards equilibrium in the silicate melt/metal melt system. The proposed kinetic model is consistent, too, with many idiosyncratic features of chemical concentration profiles observed in soda-lime float glass.