Control of the near‐surface OH concentration of float glass by anodic proton injection

• Published in: Journal of the American Ceramic Society 2020-06, Vol.103 (6), p.3642-3649
• Main Authors: Miyasaka, Satoshi, Ishiyama, Tomohiro, Hayashi, Yasuo, Omata, Takahisa
• Format: Article
• Language: English
• Subjects: Anodes; Composition; Dehydration; Electric potential; electrochemistry; Float process glass; Glass; Protons; soda‐lime‐silica; surface modification; Voltage
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.17068

Controlling the OH concentration near the float glass surface was investigated via anodic proton injection into a glass melt under conditions simulating the float glass process. A DC voltage of 1‐4 V was applied to the glass at 1000°C between the molten tin as an anode and graphite placed on the glass as a cathode. Although the OH concentration of the glass near the glass/tin interface was controlled to the same level as that in the interior of the glass when a DC voltage of 3 V was applied, the decrease in Na concentration, one order of magnitude greater than the amount of injected protons, was observed around the glass/tin interface. Therefore, the OH concentration by dehydration cannot be restored using anodic proton injection without substantial composition change. Tin was observed to be electrochemically injected into the glass when a DC voltage of >4 V was applied, and majority of the injected protons were released from the glass under the experimental conditions. Finally, the conditions that achieved an OH concentration near the glass/tin interface matching with that in the interior of the glass without substantial composition change around the anode are discussed and proposed.