Voltammetric measurement of the pt electrode capacity and the determination of the polyvalent ions diffusion coefficients in the glass melt

The cyclic voltammetry has been used to investigate the kinetic behaviour of polyvalent ions in a silicate glass melt within a temperature range from 900 to 1300°C. Standard potentials of oxidation-reduction reactions of the polyvalent elements present in glass melt as refining or colouring agents (Fe and Cr) were measured. Diffusion coefficients of Fe 3- and Cr 3- ions in the melt were calculated from the shape of cyclic voltammograms. Their values were found from 10 -9 to 10 -2 cm 2 s -1 respectively. Double layer capacity (480 μ F/cm 2 ) measured in the basic glass without of polyvalent elements corresponds to the high concentration of ions in the melt.