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- ItemHigh temperature investigation of soda-lime-silicate glasses doped with manganese and chromium(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2004) Kido, Ladislav; Müller, Matthias; Rüssel, Christian[no abstract available]
- ItemCrystalization in High Iron Containing Silicate Glasses - Electron Microscopy Investigation(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2004) Völksch, Günter; Harizanova, Ruzha; Rüssel, Christian; Mitsche, Stefan; Pölt, Peter[no abstract available]
- ItemVoltammetric methods for determining polyvalent ions in glass melts(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1987) Freude, Eberhard; Rüssel, ChristianVoltammetry is an in situ technique to investigate redox equilibria in glass melts. Its sensitivity and resolution have been improved by introducing the square-wave voltammetry. The results reported in this paper clearly demonstrate the superiority of this method over the cyclic voltammetry, which had been used so far in glass melts.
- ItemCorrosion of molybdenum electrodes in an aluminosilicate glass melt(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1991) Holzwarth, Stefan; Rüssel, Christian; Tomandl, GerhardThe corrosion of molybdenum electrodes in an aluminosilicate melt was studied with the aid of electrochemical methods at temperatures up to 1600 °C. The glass melt investigated contained polyvalent ions which enabled redox reactions with the electrode material. A layer of molybdenum oxide is formed on the electrode in contact with the glass melt. The layer partially dissolves in the glass melt and eventually evaporates into the furnace atmosphere. Dissolution of the oxide layer is assumed to be the step which determines the rate of the corrosion process.
- ItemUV-VIS spectroscopic investigations of amber glass at high temperatures(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1999) Müller, Matthias; Rüssel, Christian; Claußen, OlafThe absorption spectra of iron-containing glasses and an amber glass were recorded in the temperature ränge of 25 to 700 °C. Α shift of the UV absorption edge towards lower wave numbers with increasing temperature was found. The amount of the shift depends on the Fe³⁺ concentration. Here, the UV absorption edge may superimpose or even cover up the absorption bands of colouring ions with increasing temperatures. For an amber glass sample, with increasing temperature, the intensity of the absorption bands of the amber chromophore decreases slightly. However, above 550 °C the decomposition of the chromophore is observed. All changes are reversible when temperature is decreased again. The decomposition of the chromophore and the attributed temperature ränge are in agreement with thermodynamic calculations.
- ItemImpedance of molybdenum electrodes in a soda-lime-silica glass melt(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1991) Rüssel, ChristianImpedance measurements at molybdenum electrodes in a soda-lime-silica glass melt were carried out in a frequency range of 0.1 to 10^5 Hz. The spectra obtained were quite different depending on the DC potential superimposed. Thus, spectra obtained from anodically passivated electrodes could be clearly distinguished from those of electrodes with a MoSix-surface layer and from unprotected electrodes. Although the physical interpretation of the spectra obtained is very difficult, and up to now unsatisfactory, impedance measurements seem to be suitable for measuring and controlling passivating layers at molybdenum electrodes.
- ItemVoltammetric studies in a soda-lime-silica glass melt containing two different polyvalent ions(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1990) Rüssel, Christian; Freude, EberhardBy the aid of electrochemical methods, a quantitative determination of polyvalent ions in glass melts is possible. This paper investigates the square-wave voltammetry in soda-lime-silica glass melts doped with iron and additionally with arsenic or antimony. In principle, a simultaneous, quantitative determination of these elements is possible, but the experimental parameters should be chosen with care and the recorded current-potential curves should be carefully analyzed.
- ItemRedox State of Glasses(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2004) Rüssel, Christian[no abstract available]
- ItemInteraction between oxygen activity of Fe2O3 doped soda-lime-silica glass melts and physically dissolved oxygen(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1988) Rüssel, Christian; Kohl, Reiner; Schaeffer, Helmut Α.The oxidation state of molten soda-lime-silica glass was studied by an electrochemical oxygen-sensor, based on an yttria-stabilized zirconia solid electrolyte. It is shown that the iron concentration of the glass melt influences the extent of oxygen activity variation during cooling. If the iron concentration is 0.2 mol% Fe2O3 or less, the redox ratio [Fe3+]/[Fe2+] cannot be assumed to be independent of temperature because the redox equilibrium is shifted by the reactivity of physically dissolved oxygen.
- ItemSquare-wave voltammetry as a method for the quantitative in-situ determination of polyvalent elements in molten glass(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1988) Montel, Christian; Rüssel, Christian; Freude, EberhardMany properties of glasses, especially the color are strongly influenced by the concentration of multivalent elements. Up to now the concentration of multivalent elements can only be determined from the solid glass by chemical or physical methods. This paper introduces a method which makes possible to determine the total concentration of the multivalent ion in-situ in the glass melt by an electrochemical method. In this paper the square-wave voltammetry is used for the quantitative determination of iron in a soda-lime-shica glass melt. The area of the test electrode can be adjusted by conductivity measurements. The Fe2O3 concentration can be detected down to a lower limit of 0.015 mol%.