Oxidation-Reduction Equilibria in Molten Na2O.2SiO2 Glass |
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Authors: | W. D. JOHNSTON |
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Affiliation: | Research and Engineering Center, Pittsburgh Corning Corporation, Pittsbnrgh, Pennsylvania |
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Abstract: | The oxidation-reduction equilibria in molten glasses having a soda/silica ratio of 1/2 and containing small amounts of variable-valence ions of the transition elements titanium, vanadium, iron, cobalt, and nickel, the post-transition elements tin and antimony, and the rare-earth element cerium were obtained by equilibrating the melts with various atmospheres. The simple mass expression was always applicable. In the expression, n is the number of electrons involved in the valence change of the metal M. The value of n is 1 for all systems except for the ions of antimony and tin where n is 2. The ions found are those generally accepted as existing in glass melts which are Ti3+, Ti4+; Fez+, Fe3+; Ce3+, Ce4+; Mn2+, Mn3; Co2+, Co3+; Ni2+, Ni3; Sb3+, Sb5+; and Sn2+, Sn4+. Two mass action expressions were needed for vanadium-containing glasses to describe the equilibria between 5+, 4+, and 3 f species. |
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