Pb-Mg-Nb-O系におけるパイロクロア型化合物の組成範囲

概要

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In the Pb-Mg -Nb-O system, there is a cubic pyrochlore type compound with a formula of Pb_<1.5>Nb_2O_<6.5> In this work the solubility of Mg^<2+> cation into Nb^<5+> site was exarnined along the composition expressed by Pb_<(3+3x)>/_2Mg_xNb_<(2-x)>0_<6.5> where O≦x≦0.5, and it was clarified that Mg^<2+> cation is soluble into Pb_<1.5>Nb_2O_<6.5> and results in a solid solution. The solubility limit of Mg^<2+> cation is x=0.24 (Pb_<1.86>Mg_<0.24>Nb_<1.76>O_<6.5>) and is in good agreement with that of a single crystal grown in PbO flux. Annealing the pellet of pyrochlore type compound with x=0.24 (Pb_<1.86>Mg_<0.24>Nb_<1.76>O_<6.5>) at 1000℃ for 12h in air, brings about a lattice pararneter gradient froun the surface toward the internal part due to the evaporation of PbO. This fact also shows that pyrochlore type counpounds with various conrposition form in this system.
社団法人日本セラミックス協会の論文
1994-06-01