Oxidation–Reduction Equilibrium in Copper Phosphate Glass Melted in Air |
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Authors: | Byeong-Soo Bae Michael C Weinberg |
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Affiliation: | Arizona Materials Laboratories, Department of Materials Science and Engineering, University of Arizona, Tucson, Arizona 85712 |
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Abstract: | Copper phosphate glasses with 40, 50, and 60 mol% CuO in batch were melted in air at 1000°, 1100°, and 1200°C using quartz or alumina crucibles, and the Cu2+]/Cutotal] ratio variations with melting time were measured. Glasses were oxidized during melting and reached equilibrium Cu2+]/Cutotal] ratios which were independent of melting temperature and identical for the 40 and 50 mol% CuO content glasses. Structural considerations seemed to have determined oxidation-reduction equilibrium rather than an equilibrium redox reaction. Also, the effects of crucible type on the oxidation-reduction balance were examined. It was found that a quartz crucible is more inert and has less effect on the oxidation-reduction equilibrium of glass than an alumina crucible. Crucible contamination and phosphorus vaporization were found to diminish as the CuO content in the batch was increased. |
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Keywords: | glass copper phosphates reduction-oxidation equilibrium |
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