US 7,507,289 B2 · Electroconductive 12CaO—7Al2O3 and compound of same type, and method for preparation thereof

Abstract

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.

Claims9

Dependent claims

A method for manufacturing a 12CaO·7Al2O3 compound, a 12SrO·7Al2O3 compound, or a mixed crystal compound containing 12CaO·7Al2O3 and 12SrO·7Al2O3 comprising:

electrons substituted for free oxygen ions at a concentration of 1×1018 to less than 1.1×1021/cm3 out of free oxygen ions contained in cages at a substitution ratio of the electrons to the free oxygen ions of 2 to 1, the concentration of the electrons being 2×1018 to less than 2.2×1021/cm3 in the cages, wherein the electrical conductivity at room temperature is in the range of 10−4 S/cm to less than 103S/cm, comprising the step of:
holding a single crystal 12CaO·7Al2O3 compound or a hydrostatic pressure press molded material of a fine powder thereof, a single crystal 12SrO·7Al2O3compound or a hydrostatic pressure press molded material of a fine powder thereof, or a single crystal of a mixed crystal compound containing a 12CaO·7Al2O3 compound and a 12SrO·7Al2O3 compound or a hydrostatic pressure press molded material of a fine powder thereof at 600 to 800° C. for 4 to less than 240 hours in an alkaline metal vapor or an alkaline earth metal vapor, whereby electrons are substituted for the free oxygen ions.

Dependencies are inferred from the claim text.

Electroconductive 12CaO—7Al2O3 and compound of same type, and method for preparation thereof

Life of this patent

Electroconductive 12CaO—7Al2O3 and compound of same type, and method for preparation thereof

Life of this patent

Abstract

Claims9