Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost. A production method of an electroconductive mayenite type compound comprising a step of subjecting a precursor to heat treatment, is a method for preparing an electroconductive mayenite type compound, comprising a step of subjecting a precursor to heat treatment; wherein the precursor is a vitreous or crystalline material, which contains Ca and Al, in which a molar ratio of (CaO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, and in which a total amount of CaO and Al2O3 is at least 50 mol %, and wherein the heat treatment is heat treatment comprising holding the precursor at a heat treatment temperature T of from 600 to 1415° C. and in an inert gas or vacuum atmosphere with an oxygen partial pressure PO2 in a range of PO2?105×exp [{?7.9×l04/(T+273)}+14.4] in the unit of Pa.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost without need for expensive facilities, a reaction at high temperature and for a long period of time, or complicated control of reaction. A method for preparing an electroconductive mayenite type compound comprises a step of subjecting a precursor to heat treatment, wherein the precursor contains Ca and/or Sr, and Al, a molar ratio of (a total of CaO and SrO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, a total content of CaO, SrO and Al2O3 in the precursor is at least 50 mol %, and the precursor is a vitreous or crystalline material; and the method comprises a step of mixing the precursor with a reducing agent and performing the heat treatment of holding the mixture at 600-1,415° C. in an inert gas or vacuum atmosphere with an oxygen partial pressure of at most 10 Pa.

Abstract: To provide a method for preparing a mayenite type compound having electroconductivity imparted. A method for preparing an electroconductive mayenite type compound, which comprises melting a raw material containing Al and at least one element selected from the group consisting of Ca and Sr, holding the melt in a low oxygen partial pressure atmosphere having an oxygen partial pressure of not higher than 10 Pa, followed by cooling or annealing in a low oxygen partial pressure atmosphere or in atmospheric air for solidification, thereby to replace oxygen present in cages by electrons in a high concentration.

Abstract: To provide an electron emitter, a field emission display unit, a cold cathode fluorescent tube and a flat type lighting device, which employ an electron emitting material producible at a low cost and in a large amount. A conductive mayenite type compound powder containing at least 50 mol % of a mayenite type compound represented by a chemical formula of either 12CaO.7Al2O3 or 12SrO.7Al2O3 and having a maximum particle size of at most 100 ?m, is used as an electron emitter, whereby an electron emitter, a field emission display unit, a cold cathode fluorescent tube and a flat type lighting device, are realized that are easy to produce and capable of emitting electrons even at a low applied voltage and whereby a large current can be obtained per the same applied voltage surface.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost without need for expensive facilities, a reaction at high temperature and for a long period of time, or complicated control of reaction. A method for preparing an electroconductive mayenite type compound comprises a step of subjecting a precursor to heat treatment, wherein the precursor contains Ca and/or Sr, and Al, a molar ratio of (a total of CaO and SrO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, a total content of CaO, SrO and Al2O3 in the precursor is at least 50 mol %, and the precursor is a vitreous or crystalline material; and the method comprises a step of mixing the precursor with a reducing agent and performing the heat treatment of holding the mixture at 600-1,415° C. in an inert gas or vacuum atmosphere with an oxygen partial pressure of at most 10 Pa.

Abstract: Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost. A production method of an electroconductive mayenite type compound comprising a step of subjecting a precursor to heat treatment, is a method for preparing an electroconductive mayenite type compound, comprising a step of subjecting a precursor to heat treatment; wherein the precursor is a vitreous or crystalline material, which contains Ca and Al, in which a molar ratio of (CaO:Al2O3) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, and in which a total amount of CaO and Al2O3 is at least 50 mol %, and wherein the heat treatment is heat treatment comprising holding the precursor at a heat treatment temperature T of from 600 to 1415° C. and in an inert gas or vacuum atmosphere with an oxygen partial pressure PO2 in a range of PO2?105×exp[{?7.9×l04/(T+273)}+14.4] in the unit of Pa.

Abstract: To provide a method for preparing a mayenite type compound having electroconductivity imparted. A method for preparing an electroconductive mayenite type compound, which comprises melting a raw material containing Al and at least one element selected from the group consisting of Ca and Sr, holding the melt in a low oxygen partial pressure atmosphere having an oxygen partial pressure of not higher than 10 Pa, followed by cooling or annealing in a low oxygen partial pressure atmosphere or in atmospheric air for solidification, thereby to replace oxygen present in cages by electrons in a high concentration.