Generation of alkali-free and high-proton concentration layer in a soda lime glass using non-contact corona discharge

Abstract

Formation mechanisms of alkali-free and high-proton concentration surfaces were investigated for a soda lime glass using a corona discharge treatment under an atmospheric pressure. Protons produced by high DC voltage around an anode needle electrode were incorporated into a sodium ion site in the anode side glass. The sodium ion was swept away to the cathode side as a charge carrier. Then it was discharged. The precipitated sodium was transformed to a Na 2 CO 3 powder when the surface contacted with air. The sodium ion in the glass surface layer of the anode side was replaced completely by protons. The concentration of OH groups in the layer was balanced with the amount of excluded sodium ions. The substitution reaction of sodium ions with protons tends to be saturated according to a square root function of time. The alkali depletion layer formation rate was affected by the large difference in mobility between sodium ions and protons in the glass. V C 2013 AIP Publishing LLC. [http://dx

Selective Deposition of SiO2 on Ion Conductive Area of Soda-lime Glass Surface

“…The corona discharge is generated at the anode electrode with high voltage16171819, where the generated charged ion or particles are accelerated to the cathode electrode.…”

Inward Migration of Glass‐Modifier Cations During Heat Treatment Under an N2 Atmosphere

“…Thus, an H‐rich layer would be formed at the depth of the Na + /Ca 2+ ‐deficient layer. Ikeda et al . determined that an Na + ‐deficient and H + ‐rich layer was formed when a glass was corona‐discharged at 400°C in air.…”

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

“…In his report, when DC voltages of 50‐100 V were applied to soda‐lime silicate glass at temperatures from 300°C to 450°C under an atmosphere containing hydrogen or water vapor, depletion of sodium and calcium and injection of protons near the anode were observed. Some methods to increase the OH concentration in glasses using anodic proton injection have recently been reported, for example, proton injection by applying a small DC voltage (5‐10 V) to phosphate glass in a hydrogen‐containing atmosphere using palladium as the anode and molten tin as the cathode, and corona discharge with the application of several kilovolts in a hydrogen‐containing atmosphere over soda‐lime silicate glass placed on a carbon plate cathode . Among these proton injection methods, the application of a small DC voltage using molten tin as a cathode can be incorporated into the float process because this process involves forming glass on molten tin under a hydrogen‐containing atmosphere.…”

“…Some methods to increase the OH concentration in glasses using anodic proton injection have recently been reported, for example, proton injection by applying a small DC voltage (5-10 V) to phosphate glass in a hydrogen-containing atmosphere using palladium as the anode and molten tin as the cathode, 3 and corona discharge with the application of several kilovolts in a hydrogen-containing atmosphere over soda-lime silicate glass placed on a carbon plate cathode. 4 Among these proton injection methods, the application of a small DC voltage using molten tin as a cathode can be incorporated into the float process because this process involves forming glass on molten tin under a hydrogen-containing atmosphere. In fact, the electrochemical injection of Cu + or Pb 2+ into a float glass in a pilot or commercial plant has been previously reported.…”