M_20-M'O-SiO_2(M:アルカリ金属, M':アルカリ土類金属)ガラス融液中の鉄イオンのボルタンメトリー

概要

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The half-wave potentials of the reduction of Fe^<3+> in 16M_20 (M:Li, Na, K and Cs) ・ 10M'0 (M': Mg, Ca, Sr and Ba) ・ 74Si0_2 glass melts were examined by differential pulse voltammetry. In all melts, the half-wave potential shifted to the positive side with increasing temperature. The equilibrium of Fe^<3+>/Fe^<2+> moved toward the reduced side with increasing temperature. The replacement of Li^+ ions by larger alkali ions resulted in a positive shift of the half-wave potentials. On the other hand, the smaller the ionic radius of the alkaline-earth metal ion, the larger the half-wave potential. The Fe^<3+>/Fe^<2+> equilibrium was mainly affected by the stability of the Fe^<3+> -complex and the basicity of the melts. Variations in the kinds of alkali and alkaline-earth metal ions influenced the stability of the complex and the basicity of the melts, respectively. The half-wave potential moved toward the positive side (45 mV at 1473 K) when the atmosphere over the melts was changed from pure oxygen gas to air; thus, the reversibility of Pt: 0_2 reference electrode was confirmed.
社団法人日本セラミックス協会の論文
2003-10-01