Ceramics-Silikáty 55, (1) 54 - 58 (2011) |
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IRON REDOX EQUILIBRIUM AND DIFFUSIVITY IN MIXED ALKALI-ALKALINE EARTH-SILICA GLASS MELTS |
Kim Ki-Dong |
Department of Materials Science and Engineering,
Kunsan National University, Kunsan 573-701, Korea
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Keywords: Iron, Redox, Voltammetry, Diffusivity, Mixed alkali oxide |
Dependence of redox behavior and diffusivity of iron on temperature and composition was studied in mixed alkali-alkaline
earth-silica glass melts by means of square wave voltammetry (SWV). The voltammograms showed that irrespective of
K₂O/(Na₂O+K₂O) the peak potential due to Fe³⁺/Fe²⁺ moved toward negative direction with temperature decrease and
the peak current showed a strong dependence on frequency at constant temperature. Iron diffusion coefficient versus melt
viscosity showed a good linearity. The compositional dependence showed that the peak potential shifted to the positive
direction with increase of K₂O but a typical mixed alkali effect occurred in iron diffusion either at constant temperature or
at constant viscosity. |
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