Beta alumina (Na2O·11 Al2O3) with addition of MgO, NiO, ZnO, CuO and CaO, respectively, together with Na2O are sintered. Ionic conduction of Na+ and X-ray diffraction of these samples are investigated. Additions of above divalent ions, except for Ca2+, increase the amount of Na+ in β-alumina, leading to an increase in the ionic conduction of Na+ in β-alumina. All divalent ions effective to increase the ionic conduction are components of aluminum spinel. The limiting process of the D.C. ionic conduction of these sintered samples may be the grain-boundary conduction.

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Crystal structures, dielectric properties and electrical resistivities for partially substituted lead zinc niobate [Pb(Zn1/3Nb2/3)O3] ceramic were investigated. This ceramic, sintered at 1000–1050°C, was composed mainly of perovskite phase and showed a high dielectric constant (3500–5000) and a high resistivity (approximately 1013Ω·cm) when partial substitutions of the Pb site by Ba or Sr and the (Zn1/3Nb2/3) site by Ti in the Pb(Zn1/3Nb2/3)O3 were carried out. The reason why the perovskite phase was stable in the sintered body is explained qualitatively by introducing the concepts of an electronegativity difference and a tolerance factor.

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