Ceramics-Silikáty 55 (1) 54-58 (2011)

IRON REDOX EQUILIBRIUM AND DIFFUSIVITY IN MIXED ALKALI-ALKALINE EARTH-SILICA GLASS MELTS

K.-D. Kim

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.

Keywords: Iron, Redox, Voltammetry, Diffusivity, Mixed alkali oxide