V_2O_5-P_2O_5系ガラスの耐水性に及ぼすSb_2O_3添加の効果

概要

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In V_2O_5-P_2O_5 glass system containing a large amount of V_2O_5, addition of Sb_2O_3 was very effective to improve the water durability. To clarify this effect, the influence of Sb_2O_3 addition on the glass structure was studied. The added Sb_2O_3 acted particularly on V-ions in the glass, and caused the following redox reaction. 2V_2O_5+Sb_2O_3→4VO_2+Sb_2O_5 (2V^<5+>+Sb^<3+>→2V^<4+>+Sb<5+>) Decrease in V^<5+>-ions forming a layered structure and increase in V^<4+>-ions not forming this structure were considered to transform the glass structure from layered to three-dimensional network, which prevented water molecules from penetration. Further, this structural transformation decreased the number of sites which were attacked easily by water molecules, i. e., quasi-double bonding oxygens and three-coordinate oxygens in V_2O_5, P-O-P bonds and non-bridging oxygens, and increased stable two-coordinate oxygens (bridging oxygens). Both of the structural transformation and the increase in bridging oxygens were considered to be effective to inhibit the erosion of V_2O_5-P_2O_5 glasses with Sb_2O_3 addition by water. Further, the addition of Sb_2O_3 did not increase the characteristic temperatures of glass remarkably, because packing density of oxygens remain unchanged by the addition.
社団法人日本セラミックス協会の論文
1992-05-01