ELECTROCONDUCTIVE 12CAO.7AL2O3, 12SRO.7AL2O3 OR MIXTURE THEREOF AND METHOD FOR PREPARATION THEREOF

摘要

In a solid solution system of Al₂O₃ and CAO or SrO, it has been difficult to obtain a material having a high electrical conductivity (10^-4 S·cm^-) at room temperature.;A compound is provided in which electrons at a high concentration are introduced into a 12CaO·7Al2O3 compound, a 12SrO·7Al2O3 compound, or a mixed crystal compound containing 12CaO·7Al2O3 and 12SrO·7Al2O3. The compound formed by substituting all the free oxygen ions with electrons is regarded as an electride compound in which [Ca24Al28O64] 4+(4e-) or [Sr24Al28O64]4+(4e-) serves as a cation and electrons serve as anions. When a single crystal or a hydrostatic pressure press molded material of a fine powder thereof is held at approximately 700°C in an alkaline metal vapor or an alkaline earth metal vapor, melt of a hydrostatic pressure press molded material of a powder is held at approximately 1,600°C in a carbon crucible, followed by slow cooling for solidification, or a thin film of the compound held at approximately 600°C is implanted with rare gas ions, a great number of the free oxygen ions can be substituted with electrons.