TW201326045A - Method for producing conductive mayenite compound and electrode for fluorescent lamps - Google Patents

Abstract

A method for producing a conductive mayenite compound, which is characterized by comprising: (1) a step wherein a mayenite compound powder is prepared; and (2) a step wherein a material to be processed, which contains the mayenite compound powder prepared in the step (1), is arranged so as not to be in contact with a titanium source in the presence of a carbon monoxide gas and titanium vapor supplied from the titanium source and the material to be processed is maintained at a temperature within the range from 1,230 DEG C to 1,380 DEG C in an inert gas atmosphere other than a nitrogen atmosphere or in a reduced pressure environment.

Description

Method for producing conductive mayenite compound and electrode for fluorescent lamp

The present invention relates to a method of producing a conductive mayenite compound.

The mayenite compound has 12CaO. A representative composition represented by 7Al ₂ O ₃ and possessing a characteristic crystal structure having a void (cage) having a diameter of about 0.4 nm which is three-dimensionally joined. The skeleton constituting the cage is positively charged, and 12 cages are formed per unit lattice. Since 1/6 of the cage satisfies the electrical neutral condition of the crystal, the inside is occupied by oxygen ions. However, the oxygen ions in the cage have different chemical properties from the other oxygen ions constituting the skeleton, and therefore, the oxygen ions in the cage are especially called free oxygen ions. The mayenite compound is also described as [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ . 2O ^2- (Non-Patent Document 1).

When a part or all of the free oxygen ions in the cage of the mayenite compound are substituted with electrons, the mayenite compound is imparted with conductivity. The reason for this is that the electrons contained in the cage of the mayenite compound are less constrained by the cage and can move freely in the crystal (Patent Document 1). The mayenite compound having such conductivity is especially called a "conductive mayenite compound".

However, when the conductive mayenite compound is used as an electrode material such as a fluorescent lamp, a higher electron density of 3.0 × 10 ²⁰ cm ^-3 or more is required for the conductive mayenite compound. The reason for this is that when a conductive mayenite compound having an electron density of less than 3.0 × 10 ²⁰ cm ^-3 is used as an electrode, there is a problem that Joule heat is generated in the electrode at the time of use to make the electrode high temperature. Further, when such Joule heat is generated in the electrode at each lighting, as a result of applying thermal stress to the electrode, there is a possibility that cracks or breakage occur in the electrode to break the electrode.

Further, regarding the production of a conductive mayenite compound having a high electron density, Patent Document 2 discloses that a ceria glass tube is used as a container, and a mayenite compound is used in a vacuum atmosphere containing titanium metal. The single crystal is subjected to heat treatment, whereby a member made of a conductive mayenite compound having an electron density of 3.0 × 10 ²⁰ cm ^-3 or more can be produced.

Prior technical literature Patent literature

Patent Document 1: International Publication No. 2005/000741

Patent Document 2: International Publication No. 2006/129674

Non-patent literature

Non-Patent Document 1: F. M. Lea, C. H. Desch, The Chemistry of Cement and Concrete, 2nd ed., p. 52, Edward Arnold & Co., London, 1956

As described above, by heat-treating a single crystal of the mayenite compound in a vacuum atmosphere containing titanium metal, a member made of a conductive mayenite compound having a higher electron density of 3.0 × 10 ²⁰ cm ^-3 or more can be produced. .

However, the member made of the conductive mayenite compound obtained by this method has the feature of having a relatively thick "surface layer" on the surface.

Here, in the present invention, the term "surface layer" means that during the heat treatment of the object to be processed, the surface of the object to be treated and the components in the environment, or the free oxygen ions in the cage of the mayenite compound are used. The layer formed by the reaction, And a general term for a layer composed of a phase different from the mayenite compound.

When a member made of such a "surface layer" conductive mayenite compound having a phase composition inside the member, that is, a phase different from the mayenite compound, is used as, for example, an electrode of a fluorescent lamp, it may be produced. The following questions.

The electrodes of the fluorescent lamp must be stable as quickly as possible after using the fluorescent lamp.

In this case, when a member made of a conductive mayenite compound having a thin "surface layer" is used as an electrode, the "surface layer" is relatively quickly consumed and removed by sputtering of the electrode. Therefore, in this case, after the start of the use of the fluorescent lamp, the "surface layer" disappears until the time during which the characteristics are stabilized is relatively shortened.

On the other hand, when a member made of a conductive mayenite compound having a thick "surface layer" is used as an electrode, it takes a long time until the "surface layer" is completely removed by sputtering. Therefore, in this case, after the start of the use of the fluorescent lamp, there arises a problem that the desired characteristics cannot be obtained over a long period of time, or the characteristics are not stabilized.

Further, in order to avoid the above problem, it is considered that the "surface layer" of the member made of the conductive mayenite compound is removed by processing in one stage of mounting the member on the fluorescent lamp. However, in general, such a "surface layer" is firmly fixed to the member. Further, in many cases, the electrode usually has a complicated shape, and it is extremely difficult to remove the "surface layer" of the electrode by processing in advance. Therefore, the "surface layer" of the member must be removed during use of the fluorescent lamp by the discharge phenomenon of the fluorescent lamp.

As described above, formed on the surface of a member made of a conductive mayenite compound The "surface layer" on the top must be as thin as possible to allow the fluorescent lamp to operate quickly and stably.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a method for producing a conductive mayenite compound which does not form a "surface layer" and has a high electron density. .

The present invention provides a method for producing a conductive mayenite compound, comprising the steps of: (1) preparing a powder of a mayenite compound; and (2) carbon monoxide gas and a source of titanium In the presence of the supplied titanium vapor, the object to be treated containing the powder of the mayenite compound prepared in the above step (1) is placed in contact with the titanium source, and is subjected to an inert gas atmosphere other than nitrogen, or The object to be processed is maintained at a temperature in the range of 1230 ° C to 1380 ° C under a pressurized atmosphere.

Here, in the production method of the present invention, the object to be treated containing the powder of the mayenite compound may be a molded body of the powder containing the mayenite compound.

In particular, the object to be processed may be formed by attaching a molded body of a powder containing the mayenite compound to a conductive member.

Moreover, the present invention provides a method of producing a conductive mayenite compound, comprising the steps of: (1) preparing a sintered body comprising a mayenite compound; (2) in the presence of the carbon monoxide gas and the titanium vapor supplied from the titanium source, the object to be processed containing the sintered body containing the mayenite compound prepared in the above step (1) is placed in contact with the titanium source, The object to be treated is maintained at a temperature in the range of 1230 ° C to 1380 ° C in an inert gas atmosphere other than nitrogen or a reduced pressure atmosphere.

Further, the present invention provides a method for producing a conductive mayenite compound, comprising the steps of: (1) preparing a preform of a calcined powder; and (2) carbon monoxide gas and titanium In the presence of the titanium vapor supplied from the source, the object to be processed including the molded body of the calcined powder prepared in the above step (1) is placed in contact with the titanium source, and is placed in an inert gas atmosphere other than nitrogen. The object to be treated is maintained at a temperature ranging from 1230 ° C to 1380 ° C under a reduced pressure atmosphere.

Here, in the production method of the present invention, the step (2) may be carried out in a state in which the object to be processed and the titanium source are placed in a container containing carbon.

Further, in the production method of the present invention, the conductive mayenite compound obtained after the step (2) may have an electron density of 3.0 × 10 ²⁰ cm ^-3 or more.

Further, in the production method of the present invention, the object to be treated contains fluorine (F), and after the step (2), a conductive mayenite compound containing fluorine may be obtained.

Further, the present invention provides an electrode for a fluorescent lamp comprising the highly conductive mayenite compound produced by the above production method.

Furthermore, the present invention provides a production method for producing a target for film formation comprising a conductive mayenite compound by the above-described production method.

The present invention can provide a method for producing a conductive mayenite compound which does not form a "surface layer" and has a high electron density.

A first aspect of the present invention provides a method of producing a method for producing a conductive mayenite compound, comprising the steps of: (1) preparing a powder of a mayenite compound; and (2) carbon monoxide gas And the object to be treated containing the powder of the mayenite compound prepared in the above step (1) in a state in which it is not in contact with the titanium source in the presence of the titanium vapor supplied from the titanium source, and is inert to nitrogen removal The object to be treated is maintained at a temperature in the range of 1230 ° C to 1380 ° C in a gas atmosphere or a reduced pressure environment.

Further, a second aspect of the present invention provides a method of producing a method for producing a conductive mayenite compound, comprising the steps of: (1) preparing a sintered body comprising a mayenite compound; (2) in the presence of the carbon monoxide gas and the titanium vapor supplied from the titanium source, the object to be processed containing the sintered body containing the mayenite compound prepared in the above step (1) is placed in contact with the titanium source, The object to be treated is maintained at a temperature in the range of 1230 ° C to 1380 ° C in an inert gas atmosphere other than nitrogen or a reduced pressure atmosphere.

Further, a third aspect of the present invention provides a method of producing a method for producing a conductive mayenite compound, comprising the steps of: (1) preparing a preform of a calcined powder; and (2) In the presence of the carbon monoxide gas and the titanium vapor supplied from the titanium source, the object to be processed including the molded body of the calcined powder prepared in the above step (1) is placed in contact with the titanium source, and is removed from the nitrogen. The object to be processed is maintained at a temperature in the range of 1230 ° C to 1380 ° C in an inert gas atmosphere or a reduced pressure atmosphere.

In this case, the so-called "calcium-alumina compound" is a 12CaO with a cage structure. A general term for 7Al ₂ O ₃ (hereinafter also referred to as "C12A7") and a compound having the same crystal structure as C12A7 (isotype compound).

Further, in the present invention, the "conductive mayenite compound" means a part or all of the "free oxygen ions" contained in the cage, and the electron density of the electrons substituted by electrons is 1.0 × 10 ¹⁸ cm ^-3 or more. Stone compound. The electron density of all free oxygen ions substituted by electrons was 2.3 × 10 ²¹ cm ^-3 .

Therefore, "a mayenite compound" and "a non-conductive mayenite compound" are included in the "calcium-aluminum compound".

In the present invention, the "conductive mayenite compound" produced has an electron density of 3.0 × 10 ²⁰ cm ^-3 or more, and a "conductive mayenite compound" which can be used as an electrode of a lamp can be obtained. Hereinafter, the conductive mayenite compound having an electron density of 3.0 × 10 ²⁰ cm ^-3 or more is particularly referred to as "a highly conductive mayenite compound".

Further, in general, the electron density of the conductive mayenite compound is measured by two methods depending on the electron density of the mayenite compound. When the electron density is 1.0 × 10 ¹⁸ cm ^-3 ~ less than 3.0 × 10 ²⁰ cm ^-3 , the electron density is used to measure the diffuse reflection of the conductive mayenite compound powder, according to the Kubelka-Munk conversion (Kubelka-Munk) The absorbance of the absorption spectrum of 2.8 eV (wavelength 443 nm) (Kubelka-Munk conversion value) was calculated. This method uses the electron density to be proportional to the Kubelka-Munk conversion value. Hereinafter, a method of producing a calibration curve will be described.

Four samples having different electron densities were prepared in advance, and the electron densities of the respective samples were determined in advance based on the signal intensity of Electron Spin Resonance (ESR). The electron density which can be measured by ESR is about 1.0 × 10 ¹⁴ cm ^-3 to 1.0 × 10 ¹⁹ cm ^-3 . If the Kubelka-Munk value is plotted in logarithm and the electron density obtained by ESR is plotted as a ratio, it is set as a calibration curve. That is, in this method, the electron density is a value of an extrapolation calibration curve of 1.0 × 10 ¹⁹ cm ^-3 to 3.0 × 10 ²⁰ cm ^-3 .

On the other hand, in the case where the electron density is 3.0 × 10 ²⁰ cm ^-3 to 2.3 × 10 ²¹ cm ^-3 , the electron density is a measure of the diffuse reflection of the conductive mayenite compound powder, according to the Kubelka-Munk conversion absorption. The wavelength (energy) of the peak of the spectrum is converted. The relational expression uses the following formula: n=(-(E _sp -2.83)/0.199) ^0.782

Here, n represents an electron density (cm ^-3 ), and E _sp represents an energy (eV) of a peak of an absorption spectrum at which Kubelka-Munk conversion is performed.

Further, in the present invention, the highly conductive mayenite compound is selected from the group consisting of calcium (Ca), aluminum (Al) and oxygen as long as it has a crystal structure of C12A7 containing calcium (Ca), aluminum (Al) and oxygen (O). A portion of at least one of the atoms in (O) may also be substituted with other atoms or groups of atoms. For example, a portion of calcium (Ca) may also be selected from the group consisting of magnesium (Mg), strontium (Sr), barium (Ba), lithium (Li), sodium (Na), chromium (Cr), manganese (Mn), strontium ( One or more atoms of the group consisting of Ge), cobalt (Co), nickel (Ni), and copper (Cu) are substituted. Further, a part of aluminum (Al) may also be selected from the group consisting of bismuth (Si), germanium (Ge), boron (B), gallium (Ga), titanium (Ti), manganese (Mn), iron (Fe), bismuth ( Ce), strontium (Pr), strontium (Sc), lanthanum (La), yttrium (Y), lanthanum (Eu), yttrium (Yb), cobalt (Co), nickel (Ni) and lanthanum (Tb) One or more atoms in the group are substituted. Further, the oxygen of the skeleton of the cage may be replaced by nitrogen (N) or the like.

In the present invention, at least a part of free oxygen ions of the conductive mayenite compound was also based cages of _{^{H -, H 2 -, H}} 2-, O -, O 2 -, OH -, F -, Cl - And an anion such as S ^2- or an anion of nitrogen (N).

As described above, the member made of the highly conductive mayenite compound obtained by the prior method has a feature of having a relatively thick "surface layer" on the surface.

The "surface layer" phase composition is different from the inside of the member and is composed of a phase different from the mayenite compound. Therefore, a member made of a conductive mayenite compound having such a "surface layer" is used as, for example, a fluorescent lamp. In the extreme case, it is necessary to quickly remove the "surface layer" by sputtering during discharge to stabilize the fluorescent lamp.

However, when the electrode has a thick "surface layer", there is a problem that the time until the "surface layer" disappears and the characteristic is stabilized becomes long after the start of the use of the fluorescent lamp.

In order to cope with such a problem, the inventors of the present invention conducted an experiment on the production of a conductive mayenite compound under various conditions, and studied the influence of the production conditions on the "surface layer" of the conductive mayenite compound. As a result, the inventors of the present invention found that when heat treatment of the object to be treated containing the powder of the mayenite compound in a specific temperature range, when carbon monoxide gas and titanium source of titanium vapor are coexisted in the environment, the inventors cannot The surface layer is not grown to produce a highly conductive mayenite compound.

Therefore, the first aspect of the method for producing a highly conductive mayenite compound according to the present invention is characterized in that the object to be treated is placed in the presence of a carbon monoxide gas and a titanium source which is a titanium vapor, and is in an inert gas atmosphere other than nitrogen or The object to be treated is maintained at a temperature in the range of 1230 ° C to 1380 ° C under a reduced pressure atmosphere.

In addition, the heat treatment in the environment in which carbon monoxide gas and titanium vapor coexist is effective in suppressing the growth of the "surface layer" on the surface of the object to be treated as compared with the prior art. For the above reasons, the following cases are considered.

As in the previous manufacturing method, when only titanium vapor is present in the environment, the titanium vapor reacts with oxygen in the environment or free oxygen ions in the cage of the mayenite compound to form titanium oxide. Thereby, in the calcium as the treated body Titanium oxide is deposited on the surface of the aluminum stone compound. Here, since the mayenite compound constituting the object to be treated is an oxide, the affinity with the deposited titanium oxide is high. Therefore, the titanium oxide deposited on the surface of the object to be processed is firmly bonded to the surface of the object to be treated. Thereafter, the titanium oxide is also continuously deposited on the surface of the object to be treated, and finally a thick "surface layer" is formed.

On the other hand, in the case where titanium vapor and carbon monoxide gas coexist in the environment, the titanium vapor reacts with one of the carbon monoxide gases in the environment to form titanium carbide. Since the titanium carbide is non-oxide, the affinity with the mayenite compound constituting the object to be treated is not so high. Therefore, even if titanium carbide is deposited on the surface of the object to be treated, the titanium carbide is not fixed to the surface of the object to be treated, and is easily peeled off from the surface. Therefore, the deposit of titanium carbide is remarkably suppressed from adhering to the surface of the object to be processed or growing on the surface of the object to be treated. As a result, it is considered that a thin "surface layer" is finally formed.

Further, the inventors of the present invention have found that if only carbon monoxide gas coexists with the titanium source which becomes titanium vapor in the environment, the following problems occur.

For example, when the object to be treated of the mayenite compound is directly contacted with the titanium source, the titanium metal adheres to the surface of the object to be treated during the heat treatment. When the temperature is lowered to room temperature in this state, the solid of titanium metal is fixed to the surface of the conductive mayenite compound. Such a fixing system is firmly adhered to the conductive mayenite compound, so that it is difficult to peel or remove the anchor from the conductive mayenite compound in the next step.

Therefore, a second feature of the present invention resides in that the object to be processed is placed so as not to be in contact with the titanium source, and the object to be processed is subjected to heat treatment in this state. Thereby, the problem that the titanium metal is firmly adhered to the surface of the object to be treated can be eliminated. question.

As described above, according to the present invention, the adhesion of the anchor is remarkably suppressed by the above two features, and the "surface layer" can be grown to a relatively small thickness to produce a conductive mayenite compound having a high electron density. The thickness of the "surface layer" can be, for example, 40 μm or less.

(Manufacturing method of high-conductivity mayenite compound according to an embodiment of the present invention)

Hereinafter, a method for producing a highly conductive mayenite compound according to an embodiment of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a flow chart schematically showing a method for producing a highly conductive mayenite compound according to an embodiment of the present invention.

As shown in FIG. 1, the manufacturing method comprises the steps of: (1) preparing a powder of a mayenite compound (step S110); and (2) presenting carbon monoxide gas and titanium vapor supplied from a titanium source, The object to be treated containing the powder of the mayenite compound prepared in the above step (1) is placed in contact with the titanium source, and the object to be processed is held in an inert gas atmosphere other than nitrogen or under a reduced pressure atmosphere. The temperature in the range of 1230 ° C to 1380 ° C (step S120).

Hereinafter, each step will be described.

(Step S110: preparation procedure of mayenite powder)

Initially, a powder of the mayenite compound was prepared. The powder of the mayenite compound is synthesized and produced by heating the raw material powder to a high temperature as shown below.

First, a raw material powder for synthesizing a powder of the mayenite compound is blended.

In the raw material powder, the ratio of calcium (Ca) to aluminum (Al) is in terms of a molar ratio converted to CaO: Al ₂ O ₃ , preferably in the range of 13:6 to 10:9, more preferably 12.6:6.4. The range of ~11.7:7.3 is more preferably 12.3: 6.7 to 11.5: 7.5, and more preferably 12.2: 6.8 to 11.8: 17.2, and particularly preferably about 12: 7. When one part of calcium (Ca) is substituted by other atoms, the molar number of calcium and other atoms is regarded as the molar number of calcium. When one part of aluminum (Al) is substituted by other atoms, the molar number of aluminum and other atoms is regarded as the molar number of aluminum.

In addition, the compound used for the raw material powder is not particularly limited as long as the above ratio is maintained.

The raw material powder preferably contains calcium aluminate or at least two selected from the group consisting of a calcium compound, an aluminum compound, and calcium aluminate. The raw material powder may be, for example, a mixed powder containing a calcium compound and an aluminum compound. The raw material powder may be, for example, a mixed powder containing a calcium compound and calcium aluminate. Further, the raw material powder may be, for example, a mixed powder containing an aluminum compound and calcium aluminate. Further, the raw material powder may be, for example, a mixed powder containing a calcium compound, an aluminum compound, and calcium aluminate. Further, the raw material powder may be, for example, a mixed powder containing only calcium aluminate.

Examples of the calcium compound include calcium carbonate, calcium oxide, calcium hydroxide, calcium hydrogencarbonate, calcium sulfate, calcium metaphosphate, calcium oxalate, calcium acetate, calcium nitrate, and calcium halide. Among these, calcium carbonate, calcium oxide, and calcium hydroxide are preferred.

Examples of the aluminum compound include aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum nitrate, and aluminum halide. Among these, aluminum hydroxide and aluminum oxide are preferred. Alumina (alumina) has alpha-alumina, gamma-alumina, Δ-alumina or the like is preferably α-alumina (alumina).

The raw material powder may further contain a fluorine (F) component. Examples of the fluorine (F) component include calcium fluoride (CaF ₂ ). When a fluorine (F) component is added to the raw material powder, finally (after step S120), a conductive mayenite compound or the like having a high electron density of fluorine ions introduced into the cage can be produced.

The raw material powder containing the fluorine (F) component is not limited thereto, and for example, it may be prepared by adding calcium fluoride to the mixed powder of the calcium compound and the aluminum compound as described above.

The content of fluorine (F) in the raw material powder is not particularly limited. The content of the fluorine (F) may be selected, for example, when the chemical formula of the finally obtained conductive mayenite compound is represented by the following formula (1), and the range of x is in the range of 0 to 0.60.

(12-x) CaO. 7Al ₂ O ₃ . xCaF ₂ (1)

Then, the blended raw material powder is kept at a high temperature to synthesize the mayenite compound. The synthesis can also be carried out under an inert gas atmosphere or under vacuum, but is preferably carried out under the atmosphere.

The synthesis temperature is not particularly limited, and is, for example, in the range of 1200 ° C to 1415 ° C, preferably in the range of 1250 ° C to 1400 ° C, more preferably in the range of 1300 ° C to 1350 ° C. When it is synthesized at a temperature ranging from 1200 ° C to 1415 ° C, a mayenite compound containing a crystal structure of a large amount of C12A7 can be easily obtained. If the synthesis temperature is too low, there is a decrease in the crystal structure of C12A7. On the other hand, if the synthesis temperature is too high, the melting point of the mayenite compound is exceeded, so that the crystal structure of C12A7 is small.

The holding time of the high temperature is not particularly limited, and the holding time is also based on the synthesis. The amount and the temperature are kept to change. The holding time is, for example, 1 hour to 12 hours. The holding time is, for example, preferably from 2 hours to 10 hours, more preferably from 4 hours to 8 hours. By maintaining the raw material powder at a high temperature for 2 hours or more, a solid phase reaction can be sufficiently carried out to obtain a homogeneous mayenite compound.

A part or all of the mayenite compound obtained by the synthesis is a sintered block. The bulky mayenite compound is pulverized by a pulverizer or the like to a size of, for example, about 5 mm. Further, the pulverization treatment is carried out by an automatic mortar or a dry ball mill until the average particle diameter is about 10 μm to 100 μm. Here, the "average particle diameter" means a value measured by a laser diffraction scattering method. Hereinafter, the average particle diameter of the powder means a value measured by the same method.

Further, in the case where a fine and uniform powder is to be obtained, for example, a wet type using an alcohol (for example, isopropanol) represented by C _n H _2n+1 OH (n is an integer of 3 or more) as a solvent is used. A ball mill, a circulating bead mill, or the like can be used to refine the average particle diameter of the powder to 0.5 μm to 50 μm. As a solvent, water cannot be used. The reason is that the mayenite compound is one component of the alumina cement and easily reacts with water to form a hydrate.

By the above steps, a powder of the mayenite compound is prepared.

The mayenite compound adjusted in the form of a powder may also be a conductive mayenite compound. The reason for this is that the conductive mayenite compound is more excellent in pulverizability than the non-conductive compound.

The method for synthesizing the conductive mayenite compound is not particularly limited, and the following methods can be mentioned. For example, there is a method in which a mayenite compound is placed in a capped carbon container and heat-treated at 1600 ° C (refer to International Publication No. 2005/000741); the mayenite compound is placed in a capped carbon container, The nitrogen is heat-treated at 1300 ° C (refer to International Publication No. 2006/129674); a powder of calcium aluminate or the like prepared from calcium carbonate powder and alumina powder is placed in a covered carbon crucible, and 1300 in nitrogen. It is produced by heat treatment at °C (refer to International Publication No. 2010/041558); a powder obtained by mixing calcium carbonate powder and alumina powder is placed in a covered carbon crucible and heat-treated at 1300 ° C in nitrogen (see Japanese Patent Laid-Open Publication No. 2010-132467, and the like.

The pulverization method of the conductive mayenite compound is the same as the pulverization method of the above mayenite compound.

By the above steps, the powder of the conductive mayenite compound is adjusted. Further, a mixed powder of a mayenite compound and a conductive mayenite compound may also be used.

(Step S120: calcination step)

Then, as shown below, the powder of the mayenite compound is sintered by maintaining the object to be treated containing the powder of the obtained mayenite compound at a high temperature, and the oxygen in the cage of the mayenite compound is made. The ion and electron are substituted (reduced) to produce a highly conductive mayenite compound.

As the object to be treated containing the powder of the mayenite compound, the powder prepared in the step S110 can also be used as it is. However, in the usual case, a shaped body comprising a powder of the mayenite compound prepared in the step S110 is used as the object to be treated.

The method for forming the molded body is not particularly limited, and the molded body can be formed by using various methods previously described. For example, the shaped body may also be pressurized by a molding material including the powder prepared in step S110 or the kneaded material containing the powder. Prepared by shaping.

In the forming material, a binder, a lubricant, a plasticizer or a solvent is optionally contained. As the binder, for example, polystyrene, polyethylene, polyvinyl butyral, EVA (Ethylene Vinyl Acetate) resin, EEA (Ethylene-Ethyl Acrylat, ethylene-ethyl acrylate) resin, acrylic acid can be used. Resin, cellulose resin (nitrocellulose, ethyl cellulose), polyethylene oxide, and the like. As the lubricant, wax or stearic acid can be used. As the plasticizer, a phthalate can be used. As the solvent, an aromatic compound such as toluene or xylene, butyl acetate, rosinol, butyl carbitol acetate, and the chemical formula C _n H _2n+1 OH (n=1 to 4) can be used. An alcohol (such as isopropyl alcohol) or the like. When water is used as the solvent, the mayenite compound undergoes a chemical reaction due to hydration, so that a stable slurry cannot be obtained. The alcohol of n = 1 and 2 (e.g., ethanol) also tends to hydrate easily, and is preferably an alcohol of n = 3 or 4.

The formed body can be obtained by full-sheet forming, extrusion molding, or injection molding of the molding material. It is possible to form near-finish, that is, to produce a shape close to the final product with good productivity, and preferably injection molding.

In the injection molding, the powder of the mayenite compound and the binder are heated and kneaded in advance to prepare a molding material, and the molding material is placed in an injection molding machine to obtain a molded body having a desired shape. For example, by heating and mixing the powder of the mayenite compound and the binder, it is cooled to obtain a pellet or a powdery shaped material having a size of about 1 mm to 10 mm. In the heating and kneading, a cohesive agent is dispensed by a shearing force using a closed type kneading machine (labo plastomill) or the like, and a binder is applied to the primary particles of the powder. Will become The shaped material is placed in an injection molding machine and heated to 120 ° C to 250 ° C to exhibit fluidity in the adhesive. The mold is heated in advance at 50 ° C to 80 ° C, and a material is injected into the mold at a pressure of 3 MPa to 10 MPa, whereby a desired molded body can be obtained.

Alternatively, the above-mentioned prepared powder or kneaded product is placed in a mold, and the mold is pressurized, whereby a molded body having a desired shape can be formed. When pressurizing the mold, for example, it is also possible to use a CIP (Cold Isostatic Pressing) treatment. The pressure during CIP processing is not particularly limited, for example, 50 MPa ~ 200 MPa range.

Further, in the case of preparing a molded body and in the case where the molded body contains a solvent, the molded body may be previously held in a temperature range of 50 ° C to 200 ° C for about 20 minutes to 2 hours to volatilize and remove the solvent. Further, in the case where the molded body contains a binder, it is preferred that the molded body is held in a temperature range of from 200 ° C to 800 ° C for about 30 minutes to 6 hours or at a temperature of 50 ° C / hour to remove the binder. Or you can handle both at the same time.

Further, the object to be processed may be formed by attaching a molded body prepared by the above method to a conductive member such as metal. Thereby, after the high temperature treatment in the future, a member which can be directly used as an electrode of a fluorescent lamp or the like can be obtained.

The conductive member may be made of, for example, metallic nickel, a nickel alloy, molybdenum, tungsten or the like. Further, the shape of the conductive member is not particularly limited. The conductive member may have a shape such as a wire shape, a rod shape, a cup shape, or a short strip.

In the manufacturing method of the present invention, titanium vapor is present in a heat treatment environment. However, titanium is a metal whose vapor pressure is extremely low, and therefore reacts with other metals during heat treatment of the object to be processed to form a brittle intermetallic compound. Less likely. Therefore, even when the conductive member is contained in the object to be processed, the risk of embrittlement or breakage of the conductive member after heat treatment is remarkably suppressed. Further, in the case of using a carbon container, titanium having a low vapor pressure is less likely to form a compound, and thus deterioration of the carbon container can be suppressed.

Then, the object to be processed such as a molded body is subjected to high temperature treatment in an inert gas atmosphere other than nitrogen or in a reduced pressure environment. Thereby, sintering of the mayenite compound particles in the object to be treated is performed, and oxygen ions in the cage of the calcium aluminosilicate inclusion are electronically substituted to form a highly conductive mayenite compound.

Here, as described above, in the present invention, it is necessary to pay attention to the arrangement of the treated system in the presence of carbon monoxide gas and titanium vapor supplied from a titanium vapor source.

The high temperature treatment of the object to be processed is carried out in an inert gas atmosphere other than nitrogen or in a reduced pressure environment. The "reduced pressure environment" may be, for example, an environment having a pressure of 100 Pa or less. The oxygen partial pressure is preferably 10 ^-5 Pa or less, more preferably 10 ^-10 Pa or less, still more preferably 10 ^-15 Pa or less in an inert gas atmosphere or a reduced pressure atmosphere.

The titanium vapor source is not particularly limited, and may be, for example, a layer of titanium particles. Furthermore, as noted above, it must be noted that the system being treated is disposed in the presence of titanium vapor in a manner that is not in direct contact with the source of titanium vapor.

The carbon monoxide gas may be supplied from the outside to the environment in which the object to be treated is placed, but it is preferred to arrange the object to be processed in a container containing carbon. A carbon container can also be used, or a carbon sheet can be placed in the environment.

In order to supply the carbon monoxide gas and the titanium vapor, for example, heat treatment may be performed in a state in which the object to be treated and the titanium layer are placed in a carbon container.

The method of adjusting the reaction environment to an inert gas atmosphere or a reduced pressure atmosphere at the time of high temperature treatment of the object to be processed is not particularly limited.

For example, a container containing carbon may be placed in a vacuum atmosphere having a pressure of 100 Pa or less. In this case, the pressure is preferably 60 Pa or less, more preferably 20 Pa or less, further preferably 5 Pa or less, and particularly preferably 0.1 Pa or less.

Alternatively, an inert gas having an oxygen partial pressure of 1000 Pa or less may be supplied to a vessel containing carbon. In this case, the partial pressure of oxygen supplied to the inert gas is preferably 100 Pa or less, more preferably 10 Pa or less, still more preferably 1 Pa or less, and particularly preferably 0.1 Pa or less.

The inert gas atmosphere may also be an argon atmosphere or the like.

The treatment temperature is in the range of 1230 ° C to 1380 ° C, preferably in the range of 1280 ° C to 1340 ° C, and more preferably in the range of 1290 ° C to 1320 ° C.

The reason is that when the treatment temperature is lower than 1230 ° C, a large amount of heterophase is precipitated, and there is a possibility that sufficient conductivity cannot be imparted. Further, when the treatment temperature is higher than 1380 ° C, the crystal structure is decomposed due to the melting point of the highly conductive mayenite compound, and the electron density is lowered.

The high temperature retention time of the object to be treated is preferably in the range of 5 minutes to 48 hours, more preferably in the range of 30 minutes to 24 hours, further preferably in the range of 1 hour to 12 hours, and most preferably in the range of 4 hours to 8 hours. . When the holding time of the object to be treated is less than 5 minutes, there is a possibility that a conductive mayenite compound having a sufficiently high electron density cannot be obtained, and sintering is insufficient, and the obtained sintered body is easily deteriorated. Hey. Further, if the holding time is extended, the "surface layer" tends to be thick. Therefore, the holding time is preferably within 24 hours, and the holding time is preferably within 12 hours.

By the above steps, a highly conductive mayenite compound having a "surface layer" of 40 μm or less and an electron density of 3.0 × 10 ²⁰ cm ^-3 or more can be obtained.

Fig. 2 is a view schematically showing a configuration of a device used for high-temperature treatment of a target object.

As shown in Fig. 2, the entire apparatus 100 is composed of a heat-resistant sealed container, and the exhaust port 170 is connected to the exhaust system.

The apparatus 100 is a heat-resistant sealed container including an upper open carbon container 120, a carbon cover 130 disposed above the carbon container 120, and a separator 140 (for example, an alumina plate) disposed in the carbon container 120. A layer 150 of titanium metal powder placed on a heat-resistant dish (for example, an alumina dish) 145 is disposed at the bottom of the carbon container 120 as a titanium vapor source.

The object to be processed 160 is disposed on the upper portion of the separator 140. The separator 140 has a configuration that does not prevent the titanium vapor from the layer 150 from reaching the object to be processed 160. Further, the separator 140 must be made of a material that does not react with the titanium vapor and the object to be processed 160 when it is treated at a high temperature. For example, the separator 140 is composed of an alumina plate having a plurality of through holes.

The carbon container 120 and the carbon cover 130 are supply sources of carbon monoxide gas when the object to be processed 160 is subjected to high temperature treatment. That is, carbon monoxide gas is generated from the carbon container 120 and the carbon cap 130 side during the high temperature holding process of the object to be processed 160.

The carbon monoxide gas system suppresses oxidation of the surface of the mayenite compound powder contained in the object to be treated 160 to form a titanium oxide layer.

Further, the free oxygen ions in the cage of the mayenite compound contained in the object to be treated 160 are reduced by the titanium vapor generated from the layer 150 of the titanium metal powder in the following reaction: 2O ^2- + Ti → 4e ^- +TiO ₂ (2)

The titanium oxide produced in the reaction of (2) is formed by the following reaction in the case where one of the carbon oxide gases in the atmosphere, for example, titanium carbide is titanium carbide (TiC).

TiO ₂ +4CO → TiC+3CO ₂ (3)

Titanium carbides have poor affinity with mayenite compounds and are not fixed. Further, it is not sintered in the heat treatment temperature zone, and thus it is considered to be easily excluded.

Therefore, by using the apparatus 100 to maintain the object to be processed 160 at a high temperature, the powder of the mayenite compound contained in the object to be processed 160 can be sintered, and further, electrons can be introduced into the cage of the mayenite compound sintered body. .

Since the carbon monoxide gas and the titanium vapor coexist in the environment, a thick "surface layer" is formed on the surface of the mayenite compound sintered body.

Furthermore, it is clear to those skilled in the art that the device configuration of Fig. 2 is an example, and the device to be processed may be subjected to high temperature treatment using another device.

As an example of the present invention, an example of a method for producing a conductive mayenite compound using a target material containing a powder of a mayenite compound will be described.

However, the invention is not limited thereto. For example, a treated body containing a sintered body of a mayenite compound may be used instead of the object to be treated containing a powder of the mayenite compound.

The sintered body of the mayenite compound can be sintered, for example, by causing the mayenite compound produced by the above (calcium-alumina compound powder preparation step) to be sintered. Alternatively, a shaped body of a powder containing a mayenite compound is heat-treated to prepare.

In the latter case, the heat treatment conditions are not particularly limited as long as they are conditions for sintering the formed body. The heat treatment can be carried out, for example, in the atmosphere at a temperature ranging from 300 ° C to 1450 ° C. When it is 300 ° C or more, the organic component volatilizes and the contact of the powder increases, so that the sintering treatment is easy, and if it is 1450 ° C or less, the shape of the sintered body is easily maintained. The maximum temperature of the heat treatment is in the range of about 1000 ° C to 1420 ° C, preferably from 1050 ° C to 1415 ° C, more preferably from 1100 ° C to 1380 ° C, and particularly preferably from 1250 ° C to 1350 ° C.

The holding time in the highest temperature of the heat treatment is about 1 hour to 50 hours, preferably 2 hours to 40 hours, and more preferably 3 hours to 30 hours. Further, even if the holding time is extended, there is no particular problem in terms of characteristics. However, in consideration of the production cost, the holding time is preferably within 48 hours. It can also be carried out in an inert gas such as argon, helium, neon, or nitrogen, oxygen, or an atmosphere in which the mixture is present, or in a vacuum.

Further, a sintered body of the mayenite compound can also be produced by various methods.

Further, the mayenite compound contained in the sintered body may be a conductive mayenite compound or a non-conductive mayenite compound. Further, the mayenite compound contained in the sintered body may be a mayenite compound containing fluorine or a mayenite compound not containing fluorine.

Further, in the present invention, a target object including a molded body of a calcined powder may be used instead of the object to be treated containing a powder of the mayenite compound.

In the present invention, the term "pre-calcined powder" means a powder prepared by heat treatment, and means that (i) comprises a mixed powder of at least two selected from the group consisting of calcium oxide, aluminum oxide, and calcium aluminate. Or (ii) a mixed powder of two or more kinds of calcium aluminate. As calcium aluminate, mention may be made of CaO. Al ₂ O ₃ , 3CaO. Al ₂ O ₃ , 5CaO. 3Al ₂ O ₃ , CaO. 2Al ₂ O ₃ , CaO. 6Al ₂ O ₃ , C12A7, and the like. The ratio of calcium (Ca) to aluminum (Al) in "pre-fired powder" is 9.5:9.5 to 13:6 in terms of the molar ratio of CaO:Al ₂ O ₃ .

In particular, the ratio of calcium (Ca) to aluminum (Al) is adjusted so that the molar ratio of CaO:Al ₂ O _{3 is in} the range of 10:9 to 13:6. CaO:Al ₂ O ₃ (mole ratio) is preferably in the range of 11:8 to 12.5:6.5, more preferably in the range of 11.5:7.5 to 12.3:6.7, and further preferably in the range of 11.8:7.2 to 12.2:6.8. , especially good is about 12:7.

The calcined powder can be prepared in the following manner. First, a raw material powder is prepared. The raw material powder contains at least a raw material which is a source of calcium oxide and a source of alumina.

For example, the raw material powder preferably contains two or more kinds of calcium aluminate or at least two selected from the group consisting of a calcium compound, an aluminum compound, and calcium aluminate.

The raw material powder may be, for example, the following raw material powder: a raw material powder containing a calcium compound and an aluminum compound; a raw material powder containing a calcium compound and calcium aluminate; a raw material powder containing an aluminum compound and calcium aluminate; and a calcium compound, an aluminum compound, And raw material powder of calcium aluminate; only raw material powder containing calcium aluminate.

In the following, as a representative example, a case where the raw material powder contains at least a raw material A which is a source of calcium oxide and a raw material B which becomes an alumina source is described, and a method of preparing the calcined powder will be described.

As the raw material A, calcium carbonate, calcium oxide, calcium hydroxide, and carbon can be cited. Calcium hydrogen phosphate, calcium sulfate, calcium metaphosphate, calcium oxalate, calcium acetate, calcium nitrate, and calcium halide. Among these, calcium carbonate, calcium oxide, and calcium hydroxide are preferred.

Examples of the raw material B include aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum nitrate, and aluminum halide. Among these, aluminum hydroxide and aluminum oxide are preferred. The alumina (alumina) has α-alumina, γ-alumina, δ-alumina or the like, and is preferably α-alumina (alumina).

The calcined powder may also contain substances other than the raw material A and the raw material B. The calcined powder may or may not contain a fluorine component.

Then, the raw material powder containing the raw material A and the raw material B is subjected to heat treatment. Thereby, a calcined powder containing calcium and aluminum can be obtained. As described above, the ratio of calcium (Ca) to aluminum (Al) in the calcined powder is in the range of about 10:9 to 13:6 in terms of the molar ratio of CaO:Al ₂ O ₃ .

The maximum temperature of the heat treatment is in the range of about 600 ° C to 1,250 ° C, preferably from 900 ° C to 1,200 ° C, more preferably from 1000 ° C to 1,100 ° C. The holding time in the highest temperature of the heat treatment is about 1 hour to 50 hours, preferably 2 hours to 40 hours, more preferably 3 hours to 30 hours. Further, even if the holding time is extended, there is no particular problem in terms of characteristics. However, in consideration of the production cost, the holding time is preferably within 48 hours.

The heat treatment can also be carried out in the atmosphere. The heat treatment may also be carried out in an inert gas such as argon, helium, neon, or nitrogen, oxygen, or an atmosphere in which they are mixed, or in a vacuum.

Usually, part or all of the calcined powder obtained after the heat treatment is a sintered block. Therefore, as described above, it is also possible to carry out the above (calciumsite compound) The pulverization treatment (crude pulverization and/or miniaturization) shown in the column of the preparation of the powder. By the above steps, a calcined powder is prepared.

Then, the calcined powder prepared as described above was used to form a molded body. The method of forming the molded body can be applied to the same method as the method of forming the molded body of the above-described powder containing the mayenite compound, and therefore, the description thereof will be omitted.

Example

Next, an embodiment of the present invention will be described.

(Example 1)

A highly conductive mayenite compound was produced in the following manner.

(Synthesis of mayenite compound)

Mixed calcium carbonate (CaCO ₃ , manufactured by Kanto Chemical Co., Ltd.) powder 313.5 g, with alumina, in a molar ratio of 12:7 in terms of molar ratio of calcium oxide (CaO):alumina (Al ₂ O ₃ ) (α-Al ₂ O ₃ , manufactured by Kanto Chemical Co., Ltd., special grade) powder 186.5 g. Then, the mixed powder was heated to 1,350 ° C at a temperature elevation rate of 300 ° C / hour in the atmosphere, and kept at 1350 ° C for 6 hours. Thereafter, it was cooled at a cooling rate of 300 ° C / hour to obtain a white block of about 362 g.

Then, the white block was pulverized so as to have a size of about 5 mm by an alumina masher, and then coarsely pulverized by an automatic mortar made of alumina to obtain white particles (hereinafter referred to as particles). "A1"). The particle size of the obtained particle A1 was measured by a laser diffraction scattering method (SALD-2100, manufactured by Shimadzu Corporation), and as a result, the average particle diameter was 20 μm.

Then, 350 g of particles A1, 5 mm diameter zirconia balls 3 kg, and 350 ml of an industrial EL grade isopropyl alcohol as a pulverization solvent was placed in a 2-liter zirconia container, and after the zirconia cap was placed on the container, the ball mill pulverization treatment was carried out for 16 hours at a rotation speed of 94 rpm.

After the treatment, the obtained slurry was subjected to suction filtration to remove the pulverization solvent. Further, the remaining material was placed in an oven at 80 ° C and dried for 10 hours. Thereby, a white powder (hereinafter referred to as powder "B1") was obtained. As a result of X-ray diffraction analysis, it was confirmed that the obtained powder B1 was a C12A7 structure. Further, it was found that the average particle diameter of the powder B1 obtained by the above-described laser diffraction scattering method was 3.3 μm.

(Production of a body of a mayenite compound)

79.8 g of the powder B1 of the mayenite compound obtained by the above method, 13.0 g of polyethylene oxide as a binder for forming, 0.2 g of dibutyl phthalate as a plasticizer, and as a lubricant Stearic acid 7.0 g, heated to 150 ° C for mixing. The obtained kneaded material was poured into a molding die for injection molding, and cooled to room temperature. Thereby obtaining a diameter of 3.4 mm A molded body C1 of a rod shape of 15 mm in length.

Then, the debonding agent treatment of the molded body C1 is performed.

The formed body C1 was placed in an electric furnace in the state of being placed on an alumina plate, and heated in the air for 40 minutes up to 200 °C. Further, after heating to 8 ° C for 8 hours, it was cooled to room temperature over 2 hours. The degreased molded body is white and maintains a rod shape.

(Production of highly conductive mayenite compound)

Then, the degreased molded body C1 was subjected to a calcination treatment at a high temperature using the apparatus shown in Fig. 3 to prepare a conductive mayenite compound.

Fig. 3 is a view showing the apparatus used for the calcination treatment of the molded body C1 after degreasing.

As shown in FIG. 3, the apparatus 300 includes an alumina container 310 and a carbon container 330 with a cover 335 made of carbon. Further, a titanium layer 320 composed of 0.8 g of titanium metal powder was placed on the bottom of the alumina container 310. The titanium layer 320 is a titanium vapor source that generates titanium vapor when the device 300 is at a high temperature.

The alumina container 310 has a substantially cylindrical shape having an outer diameter of 20 mm, an inner diameter of 18 mm, and a height of 10 mm, and the rough edge is treated so that the titanium vapor is diffused to the entire carbon container 330. Further, the carbon container 330 has a substantially cylindrical shape having an outer diameter of 50 mm, an inner diameter of 40 mm, and a height of 60 mm.

This device 300 is used in the following manner.

First, an alumina plate 315 is disposed on the upper portion of the alumina container 310 having the titanium layer 320. Then, a plurality of the above-mentioned degreased molded bodies C1 are placed on the alumina plate 315. In this state, the formed body C1 is not in direct contact with the titanium layer 320.

Further, the whole is placed in the carbon container 330, and a carbon cover 335 is placed on the upper portion of the carbon container 330.

The device 300 is then placed in an electric furnace of adjustable atmosphere. Further, the inside of the furnace was evacuated using a rotary pump and a diffusion pump. Thereafter, after the pressure in the furnace became 0.1 Pa or less, the heating of the apparatus 300 was started, and the temperature was raised to 1300 ° C in 2 hours. After the apparatus 300 was kept in this state for 6 hours, it was cooled to room temperature in 2 hours.

By this heat treatment, the molded body C1 is sintered to obtain a sintered body having a black surface (hereinafter referred to as a sintered body "D1"). The relative of the sintered body D1 The density is 96.6%.

In order to extract a sample for electron density measurement, coarse pulverization of the sintered body D1 was carried out by an automatic mortar made of alumina. The coarse pulverization was carried out using an alumina mortar and an automatic mortar made of alumina.

The powder obtained was darker brown. As a result of X-ray diffraction analysis, it was found that the powder had only a C12A7 structure. Further, the electron density determined from the peak position of the light-diffusing reflectance spectrum of the obtained powder was 1.6 × 10 ²¹ cm ^-3 , and the electric conductivity was 16 S / cm. From this, it was confirmed that the sintered body D1 is a highly conductive mayenite compound.

Further, a cross section of the sintered body D1 was observed using an SEM (Scanning Electron Microscope). From the results of the cross-sectional observation, it was confirmed that the sintered body D1 was in a state of being small and dense. Further, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, so that the surface layer was extremely thin.

(Example 2)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, in Example 2, in the above step (manufacture of a highly conductive mayenite compound), the heat treatment temperature was set to 1,320 °C. Other conditions are the same as those in the first embodiment.

Thus, after the above step (manufacturing of the highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body "D2") can be obtained. The relative density of the sintered body D2 was 96.6%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D2 by the same method as in Example 1, the sintered body D2 had only a C12A7 structure. The sintered body D2 had an electron density of 1.6 × 10 ²¹ cm ^-3 and a conductivity of 16 S / cm.

From the above, it was confirmed that the sintered body D2 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D2 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Example 3)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 3 is in the above step (manufacturing of a highly conductive mayenite compound), and the heat treatment temperature is set to 1280 °C. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described step of producing the highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D3") can be obtained. The relative density of the sintered body D3 was 98.5%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D3 by the same method as in Example 1, the sintered body D3 had only a C12A7 structure. The sintered body D3 had an electron density of 1.7 × 10 ²¹ cm ^-3 and a conductivity of 17 S / cm.

From the above, it was confirmed that the sintered body D3 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D3 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Example 4)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 4 is in the step of the above (production of a highly conductive mayenite compound), and the heat treatment time is set to 12 hours. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described step (production of a highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body "D4") can be obtained. The relative density of the sintered body D4 was 97.5%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D4 by the same method as in Example 1, the sintered body D4 had only a C12A7 structure. The sintered body D4 had an electron density of 1.7 × 10 ²¹ cm ^-3 and a conductivity of 17 S / cm.

From the above, it was confirmed that the sintered body D4 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D4 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 15 μm, and the surface layer was extremely thin.

(Example 5)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 5 is in the above-mentioned step (production of a highly conductive mayenite compound), and the heat treatment time was set to 48 hours. Other conditions are the same as those in the first embodiment.

Thereby, after the step of the above (manufacturing of the highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body "D5") can be obtained. The relative density of the sintered body D5 was 96.0%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D5 by the same method as in Example 1, the sintered body D5 had only a C12A7 structure. The sintered body D5 had an electron density of 1.4 × 10 ²¹ cm ^-3 and a conductivity of 14 S / cm.

From the above, it was confirmed that the sintered body D5 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D5 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 15 μm, and the surface layer was extremely thin.

(Example 6)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 6 was carried out in the above-mentioned step (manufacturing of a highly conductive mayenite compound), and the heat treatment time was set to 96 hours. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described step (production of a highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body "D6") can be obtained. The relative density of the sintered body D6 was 96.7%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D6 by the same method as in Example 1, the sintered body D6 had only a C12A7 structure. The sintered body D6 had an electron density of 1.5 × 10 ²¹ cm ^-3 and a conductivity of 15 S / cm.

From the above, it was confirmed that the sintered body D6 is a highly conductive mayenite compound.

Further, the surface of the sintered body D6 was evaluated by the same method as in Example 1. As a result of the thickness of the layer, it was confirmed that the thickness of the surface layer was about 5 μm to about 20 μm, so that the surface layer was extremely thin.

Further, when the results of Comparative Example 5 and Example 6 were compared, it was found that the relative density and the electron density hardly changed. From this, it is considered that even if the calcination treatment time is longer than 48 hours, it is difficult to further increase the electron density. Therefore, from the viewpoint of suppressing the growth of the surface layer, it is considered that the holding time is preferably within about 50 hours.

(Example 7)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 7 is in the step of the above (production of a highly conductive mayenite compound), and the heat treatment time is set to 0.5 hour. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described step of producing a highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D7") can be obtained. The relative density of the sintered body D7 was 95.2%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D7 by the same method as in Example 1, the sintered body D7 had only a C12A7 structure. The sintered body D7 had an electron density of 1.0 × 10 ²¹ cm ^-3 and a conductivity of 10 S / cm.

From the above, it was confirmed that the sintered body D7 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D7 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Example 8)

A highly conductive mayenite compound was produced by the same method as in the above Example 1. However, in the eighth embodiment, the titanium metal layer 320 in the above step (the production of the high-conductivity mayenite compound) was used once under the same conditions as those in the first embodiment. Other conditions are the same as those in the first embodiment.

Thereby, after the above (manufacture of the highly conductive mayenite compound) step, a sintered body having a black surface (hereinafter referred to as a sintered body "D8") can be obtained. The relative density of the sintered body D8 was 97.2%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D8 by the same method as in Example 1, the sintered body D8 had only a C12A7 structure. The sintered body D8 had an electron density of 1.5 × 10 ²¹ cm ^-3 and a conductivity of 16 S / cm.

From the above, it was confirmed that the sintered body D8 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D8 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

From this result, it is understood that the titanium metal layer 320 can be reused. Incidentally, it was confirmed from the subsequent experiments that in the apparatus 300, even if the titanium metal layer 320 was used five times, a substantially equivalent high-performing mayenite compound was obtained.

(Example 9)

A highly conductive mayenite compound was produced by the same method as in the above Example 1. However, in the step of the above (the production of the formed body of the mayenite compound), the use of the powder does not use the mayenite compound, but the electron density is 5.0 × 10 ¹⁹ cm ^-3 . A powder of a conductive mayenite compound. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described (production of a highly conductive mayenite compound) step, a sintered body having a black surface (hereinafter referred to as a sintered body "D9") can be obtained. The relative density of the sintered body D9 was 96.5%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D9 by the same method as in Example 1, the sintered body D9 had only a C12A7 structure. The sintered body D9 had an electron density of 1.6 × 10 ²¹ cm ^-3 and a conductivity of 17 S / cm.

From the above, it was confirmed that the sintered body D9 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D9 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Embodiment 10)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 10 is in the above step (manufacture of a highly conductive mayenite compound), and a diffusion pump is not used in the vacuum treatment. Therefore, in this embodiment 10, the pressure in the furnace is about 50 Pa. Other conditions are the same as those in the first embodiment.

Thereby, after the step of the above (manufacturing of the highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body "D10") can be obtained. The relative density of the sintered body D10 was 96.3%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D10 by the same method as in Example 1, the sintered body D10 has only a C12A7 structure. The sintered body D10 had an electron density of 1.1 × 10 ²¹ cm ^-3 and a conductivity of 11 S / cm.

From the above, it was confirmed that the sintered body D10 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D10 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 20 μm to about 40 μm, and the surface layer was extremely thin.

(Example 11)

A highly conductive mayenite compound was produced by the same method as in the above Example 1. However, in the above-described step (the production of the high-conductivity mayenite compound), the molded article C1 of the mayenite compound was not produced, but the calcination treatment was carried out in the state of the powder of the mayenite compound. Other conditions are the same as those in the first embodiment.

Thereby, after the step of the above (manufacturing of the highly conductive mayenite compound), a part of the surface which is black and partially sintered (hereinafter referred to as sintered body "D11") can be obtained.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D11 by the same method as in Example 1, the sintered body D11 has only a C12A7 structure. The electron density of the sintered body D11 was 1.5 × 10 ²¹ cm ^-3 .

From the above, it was confirmed that the sintered body D11 is a highly conductive mayenite compound.

Further, the surface of the sintered body D11 was evaluated by the same method as in Example 1. As a result of the thickness of the layer, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, so that the surface layer was extremely thin.

(Embodiment 12)

A highly conductive mayenite compound was produced by the same method as in the above Example 1. However, in the above-described step (in the production of the formed body of the mayenite compound), the nickel wire is inserted into the molded body C1 instead of the molded body C1, and this is used as the object to be processed.

The treated system was produced as follows.

First, a hole having a diameter of about 0.7 mm and a depth of about 2.5 mm is formed at the center of one of the bottom faces of the formed body C1 using a Leutor. Then, a nickel wire having a wire diameter of 0.7 mm and a length of 10 mm heated to 150 ° C was inserted into the hole. Since the nickel wire is heated, the resin in contact with the molded body C7 is softened, and the nickel wire can be easily inserted.

A molded body to which a nickel wire is attached is produced in the above manner. Other conditions are the same as those in the first embodiment.

Thereby, after the step of the above (manufacturing of the highly conductive mayenite compound), a black sintered body (hereinafter referred to as a sintered body "D12") bonded to a nickel wire can be obtained. The relative density of the portion other than the nickel wire of the sintered body D12 was 96.7%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D12 by the same method as in Example 1, the sintered body D12 has only a C12A7 structure. The sintered body D12 had an electron density of 1.6 × 10 ²¹ cm ^-3 and a conductivity of 16 S / cm.

According to the above situation, it is confirmed that the sintered body D12 is a highly conductive calcium-aluminum petrochemical compound. Things.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D12 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

Further, it is understood that the nickel wire is not bent even if it is bent about 10 times, and does not cause deterioration such as embrittlement.

(Example 13)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 13 is in the above step (manufacturing of a highly conductive mayenite compound), and the heat treatment temperature is set to 1360 °C. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described step of producing the highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D13") can be obtained. The relative density of the sintered body D13 was 97.8%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D13 by the same method as in Example 1, the sintered body D13 has only a C12A7 structure. The sintered body D13 had an electron density of 1.5 × 10 ²¹ cm ^-3 and a conductivity of 15 S / cm.

From the above, it was confirmed that the sintered body D13 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D13 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 20 μm, and the surface layer was extremely thin.

(Example 14)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Example 14 is in the above step (manufacturing of a highly conductive mayenite compound), and the heat treatment temperature is set to 1,250 °C. Other conditions are the same as in the case of Embodiment 1.

Thus, after the above step (manufacturing of the highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body "D14") can be obtained. The relative density of the sintered body D14 was 96.0%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D14 by the same method as in Example 1, the sintered body D14 has only a C12A7 structure. The sintered body D14 had an electron density of 1.0 × 10 ²¹ cm ^-3 and a conductivity of 10 S / cm.

From the above, it was confirmed that the sintered body D14 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D14 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Example 15)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, in the above-mentioned step (the production of the high-conductivity mayenite compound), the time from the heating at room temperature to 1300 ° C was set to 4 hours, and the temperature was cooled from 1300 ° C to room temperature. The time is set to 4 hours. Other conditions are the same as those in the first embodiment.

Thereby, after the above step (manufacturing of a highly conductive mayenite compound), a sintered body having a black surface (hereinafter referred to as a sintered body) can be obtained. "D15"). The relative density of the sintered body D15 was 97.0%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D15 by the same method as in Example 1, the sintered body D15 had only a C12A7 structure. The sintered body D15 had an electron density of 1.5 × 10 ²¹ cm ^-3 and a conductivity of 15 S / cm.

From the above, it was confirmed that the sintered body D15 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D15 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Comparative Example 1)

The production of the highly conductive mayenite compound was attempted by the same method as in the above Example 1. However, this Comparative Example 1 was carried out in the above step (manufacturing of a highly conductive mayenite compound), and the heat treatment temperature was set to 1200 °C. Other conditions are the same as those in the first embodiment.

Thereby, after the above-described step of producing a highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D51") can be obtained.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D51 by the same method as in Example 1, it is understood that the sintered body D51 has a heterogeneous phase other than the C12A7 structure. Since the sintered body D51 has a different phase, the electron density and the electrical conductivity cannot be obtained.

(Comparative Example 2)

High conductivity manganite was tried by the same method as in the above Example 1. Production of compounds. However, in Comparative Example 2, in the above step (manufacturing of a highly conductive mayenite compound), the heat treatment temperature was set to 1400 °C. Other conditions are the same as those in the first embodiment.

By this, after the above-described step of producing the highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D52") can be obtained. The sintered body D52 is highly deformed and does not maintain its original shape. Therefore, the relative density cannot be measured.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D52 by the same method as in Example 1, it is understood that the sintered body D52 has a hetero phase in addition to the C12A7 structure. Since the sintered body D52 has a different phase, the exact electron density and conductivity are not clear, but it is estimated that the electron density of the sintered body D52 is about 7.7 × 10 ¹⁹ cm ^-3 .

From the above, it was confirmed that the sintered body D52 did not have a high electron density.

(Comparative Example 3)

The production of the highly conductive mayenite compound was attempted by the same method as in the above Example 10. However, in Comparative Example 3, in the apparatus 300 used in the above-described step of producing a highly conductive mayenite compound, only the alumina container 310 and the alumina plate 315 were used without using the carbon container 330 with the lid 335. . Other conditions are the same as those in the embodiment 10.

Thereby, after the above-mentioned (production of a highly conductive mayenite compound) step, a sintered body having a white surface (hereinafter referred to as a sintered body "D53") can be obtained. The relative density of the sintered body D53 was 92.0%.

Further, the sintered body D53 was pulverized by the same method as in the first embodiment. As a result of the X-ray diffraction of the obtained powder, it was found that the sintered body D53 had only the C12A7 structure. The electron density of the sintered body D53 was not more than the measurement limit. From the above, it was confirmed that the sintered body D53 was not a highly conductive mayenite compound.

(Comparative Example 4)

The production of the highly conductive mayenite compound was attempted by the same method as in the above Example 1. However, in Comparative Example 4, in the apparatus 300 used in the above-described step of producing a highly conductive mayenite compound, the titanium metal layer 320 was not used. That is, in Comparative Example 5, the calcination treatment of the molded body C1 was carried out in an environment where titanium vapor was not present. Other conditions are the same as those in the first embodiment.

Thereby, after the above (manufacture of the highly conductive mayenite compound) step, a sintered body having a black surface (hereinafter referred to as a sintered body "D54") can be obtained. The relative density of the sintered body D54 was 99.7%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D54 by the same method as in Example 1, the sintered body D54 had only a C12A7 structure. However, the electron density determined by Kubelka-Munk conversion was 4.0 × 10 ¹⁹ cm ^-3 and the electric conductivity was 0.04 S/cm according to the light diffusion reflection spectrum of the obtained powder.

From the above, it was confirmed that the sintered body D54 did not have a high electron density.

(Comparative Example 5)

The production of the highly conductive mayenite compound was attempted by the same method as in the above Example 1. However, this Comparative Example 5 is based on the above (highly conductive calcium aluminum) In the apparatus 300 used in the step of producing the stone compound, the formed body C1 of the mayenite compound is directly placed on the titanium metal layer 320 without using the alumina plate 315. Other conditions are the same as those in the first embodiment.

Thereby, after the above (manufacture of the highly conductive mayenite compound) step, a sintered body (hereinafter referred to as a sintered body "D55") can be obtained. The surface of the sintered body D55 in contact with the metallic titanium layer 320 becomes white. The relative density of the sintered body D55 from which the white substance was removed was 94.4%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D55 by the same method as in Example 1, the sintered body D55 had only a C12A7 structure. The sintered body D55 had an electron density of 1.6 × 10 ²¹ cm ^-3 and a conductivity of 16 S / cm.

The morphology of the surface of the sintered body D55 was observed by the same method as in Example 1. As a result, a white layer having a thickness of about 10 μm was present on the surface of the sintered body D55, and another layer was observed directly below it. This additional layer has the same morphology as the surface layer in other sintered bodies (for example, sintered body D1). It is confirmed that the thickness of the additional layer is also about 40 μm to about 50 μm so as to be thick.

(Comparative Example 6)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, this Comparative Example 6 is in the above-described step (production of a highly conductive mayenite compound), and the atmosphere in which the heat treatment is performed is a nitrogen atmosphere. Other conditions are the same as those in the first embodiment.

Thus, after the above-described step of producing the highly conductive mayenite compound, a sintered body having a cream color (hereinafter referred to as a sintered body "D56") can be obtained. The relative density of the sintered body D56 was 97.8%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D56 by the same method as in Example 1, the sintered body D56 had only a C12A7 structure. The electron density of the sintered body D56 was not more than the measurement limit. From the above, it was confirmed that the sintered body D56 was not a highly conductive mayenite compound.

Table 1 summarizes the types of the objects to be treated, the sources of CO and the source of titanium in Examples 1 to 15 and Comparative Examples 1 to 6, the treatment temperature, the treatment time, and the electron density and relative density of the obtained sintered body. And the thickness of the surface layer.

(Example 21)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, in the step of the above (the production of the highly conductive mayenite compound), the sintered body E21 of the mayenite compound (non-conductive) was used instead of the molded body C1 after the degreasing. Other conditions are the same as those in the first embodiment.

Further, the sintered body E21 of the mayenite compound was produced in the following manner.

First, the molded body C1 obtained through the step of producing the formed body of the mayenite compound of the above-mentioned Example 1 was placed on an alumina plate and heated in the air until 1100 °C. The heating rate was set to 300 ° C / hour. Then, the formed body C1 was kept at 1100 ° C for 2 hours, and then cooled to room temperature at a cooling rate of 300 ° C / hour. Thereby, the sintered body E21 of the non-conductive mayenite compound can be obtained.

The above step (production of a highly conductive mayenite compound) is carried out using the sintered body E21. Thereby, a sintered body having a black surface (hereinafter referred to as a sintered body "D21") can be obtained. The relative density of the sintered body D21 was 95.8%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D21 by the same method as in Example 1, the sintered body D21 had only a C12A7 structure. The sintered body D21 had an electron density of 1.6 × 10 ²¹ cm ^-3 and a conductivity of 16 S / cm.

From the above, it was confirmed that the sintered body D21 is a highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D21 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was from about 5 μm to about 10 μm. Right, so the surface layer is extremely thin.

(Example 22)

A conductive mayenite compound was produced by the same method as in the above Example 1. However, in the step (in the production of the formed body of the mayenite compound), the molded article C22 was prepared by using a mixed powder containing a fluorine component instead of the powder B1. Other conditions are the same as those in the first embodiment.

Further, the mixed powder F22 was produced by the following procedure.

(Preparation method of mixed powder)

First, 0.73 g of calcium fluoride (GaF ₂ , manufactured by Kanto Chemical Co., Ltd.) powder was added to 38.72 g of the powder B1 obtained by the method described in the section (Synthesis of the mayenite compound) of Example 1. 0.55 g of a powder of alumina (α-Al ₂ O ₃ , manufactured by Kanto Chemical Co., Ltd.) was thoroughly mixed, and a mixed powder F22 was obtained.

When it is assumed that the composition ratio of Ca/Al/F of the mixed powder F22 is also maintained in the finally produced mayenite compound, the produced mayenite compound is represented by the following chemical formula, in particular, x=0.32.

(12-x) CaO. 7Al ₂ O ₃ . xCaF ₂ (1)

The above step (production of a highly conductive mayenite compound) is carried out using the molded body C22 produced by using the mixed powder F22. By this, after the above-described step of producing a highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D22") can be obtained. The relative density of the sintered body D22 was 97.2%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D22 by the same method as in Example 1, the sintered body D22 had only a C12A7 structure. The sintered body D22 had an electron density of 1.1 × 10 ²¹ cm ^-3 and a conductivity of 12 S / cm.

Then, as a result of measuring the lattice constant of the sintered body D22, the lattice constant of the sintered body D22 was smaller than that of the sintered body D1 in the first embodiment. According to the above, it is considered that the sintered body D22 contains fluorine in the mayenite compound.

Then, the black substance D22 was broken, and the composition analysis of the fracture surface was performed by Energy Dispersive X-ray Analysis (EDX). According to the analysis results, the ratio of the detected fluorine was close to the mixing ratio of the mixed powder F22.

Thus, it was confirmed that the sintered body D22 is a sintered body of a fluorine-containing highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D22 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Example 23)

A conductive mayenite compound was produced by the same method as in the above Example 22. However, this Example 23 was added to the above-mentioned (preparation method of the mixed powder), and added calcium fluoride (CaF ₂ , manufactured by Kanto Chemical Co., Ltd.) powder of 0.12 g, and alumina (α) to 39.78 g of powder B1. -Al ₂ O ₃ , manufactured by Kanto Chemical Co., Ltd., special grade) powder 0.09 g, and the mixture was thoroughly mixed to obtain a mixed powder F23.

When it is assumed that the composition ratio of Ca/Al/F of the mixed powder F23 is also maintained in the finally produced mayenite compound, the manufactured mayenite compound is represented by the above chemical formula (3), especially as x. =0.06.

Other conditions were the same as in Example 22.

The above step (production of a highly conductive mayenite compound) is carried out using the molded body C23 produced by the mixed powder F23. By this, after the above-described step of producing a highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D23") can be obtained. The relative density of the sintered body D23 was 96.0%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D23 by the same method as in Example 1, the sintered body D23 has only a C12A7 structure. The sintered body D23 had an electron density of 1.1 × 10 ²¹ cm ^-3 and a conductivity of 11 S / cm.

Then, as a result of measuring the lattice constant of the sintered body D23, the lattice constant of the sintered body D23 was smaller than that of the sintered body D1 in the first embodiment. According to the above, it is considered that the sintered body D23 contains fluorine in the mayenite compound.

Then, the black substance D23 was broken, and the composition analysis of the fracture surface was performed by energy dispersive X-ray analysis (EDX). According to the analysis results, the ratio of the detected fluorine was close to the mixing ratio of the mixed powder F23.

Thus, it was confirmed that the sintered body D23 is a sintered body of a fluorine-containing highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D23 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Example 24)

A conductive mayenite compound was produced by the same method as in the above Example 22. However, this Example 24 was added to the above-mentioned (preparation method of the mixed powder), and calcium fluoride (CaF ₂ , manufactured by Kanto Chemical Co., Ltd., special grade) powder of 1.07 g, and alumina (α) was added to 38.11 g of powder B1. -Al ₂ O ₃ , manufactured by Kanto Chemical Co., Ltd., special grade) 0.82 g of powder, and the mixture was thoroughly mixed to obtain a mixed powder F24.

When it is assumed that the composition ratio of Ca/Al/F of the mixed powder F24 is also maintained in the finally produced mayenite compound, the manufactured mayenite compound is represented by the above chemical formula (3), especially as x. =0.48.

Other conditions were the same as in Example 22.

The above step (production of a highly conductive mayenite compound) is carried out using the molded body C24 produced by using the mixed powder F24. Thereby, after the above-described step of producing the highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D24") can be obtained. The relative density of the sintered body D24 was 95.7%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D24 by the same method as in Example 1, the sintered body D24 had only a C12A7 structure. The sintered body D24 had an electron density of 1.0 × 10 ²¹ cm ^-3 and a conductivity of 10 S / cm.

Then, as a result of measuring the lattice constant of the sintered body D24, the lattice constant of the sintered body D24 was smaller than that of the sintered body D1 in the first embodiment. From the above, it is considered that the sintered body D24 contains fluorine in the mayenite compound.

Then, the black substance D24 was broken, and the composition analysis of the fracture surface was performed by energy dispersive X-ray analysis (EDX). According to the analysis results, the ratio of the detected fluorine was close to the mixing ratio of the mixed powder F24.

Thus, it was confirmed that the sintered body D24 is a highly conductive calcium-aluminum petrochemical compound containing fluorine. a sintered body of matter.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D24 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

(Embodiment 25)

A conductive mayenite compound was produced by the same method as in the above Example 22. However, in the step 25 of the above (manufacturing of the highly conductive mayenite compound), the sintered body E25 containing the mayenite compound (non-conductive) of fluorine is used instead of the formed body C22. Other conditions are the same as those in the embodiment 22.

Further, the sintered body E25 of the calcium-aluminum petrochemical content was produced in the following manner.

First, the formed body C22 of the above Example 22 was placed on an alumina plate and heated in the air until 1100 °C. The heating rate was set to 300 ° C / hour. Then, the formed body C22 was kept at 1,100 ° C for 2 hours, and then cooled to room temperature at a cooling rate of 300 ° C / hour. Thereby, the sintered body E25 containing the fluorine-containing non-conductive mayenite compound can be obtained.

The above step (production of a highly conductive mayenite compound) is carried out using the sintered body E25. Thereby, after the above-described step of producing a highly conductive mayenite compound, a sintered body having a black surface (hereinafter referred to as a sintered body "D25") can be obtained. The relative density of the sintered body D25 was 95.6%.

Further, as a result of X-ray diffraction of the powder obtained by pulverizing the sintered body D25 by the same method as in Example 1, the sintered body D25 has only a C12A7 structure. The sintered body D25 had an electron density of 1.0 × 10 ²¹ cm ^-3 and a conductivity of 10 S / cm.

Then, as a result of measuring the lattice constant of the sintered body D25, the lattice constant of the sintered body D25 was smaller than that of the sintered body D1 in the first embodiment. According to the above, it is considered that fluorine is contained in the mayenite compound.

Then, the black substance D25 was broken, and the composition analysis of the fracture surface was performed by energy dispersive X-ray analysis (EDX). According to the analysis results, the ratio of the detected fluorine was close to the mixing ratio of the mixed powder F22.

Thus, it was confirmed that the sintered body D25 is a sintered body of a fluorine-containing highly conductive mayenite compound.

Further, as a result of evaluating the thickness of the surface layer of the sintered body D25 by the same method as in Example 1, it was confirmed that the thickness of the surface layer was about 5 μm to about 10 μm, and the surface layer was extremely thin.

Table 2 summarizes the types of the objects to be treated in Examples 21 to 25, the presence or absence of the CO source and the titanium source, the treatment temperature, the treatment time, and the electron density, relative density, and thickness of the surface layer of the obtained sintered body. .

In addition, in Table 2, the numerical value in the column of "F addition amount (x value)" shows the amount of fluorine (F) contained in the to-be-processed object. This value means the value of x when it is assumed that the mayenite compound finally represented by the following formula (1) is produced from the object to be processed.

(12-x) CaO. 7Al ₂ O ₃ . xCaF ₂ (1)

Industrial availability

The present invention can be applied to a target for sputtering necessary for forming a thin film of an electron injecting layer of an organic EL (Electro-Luminescence) element, or a member made of a conductive mayenite compound which can be used in a fluorescent lamp or the like. Production method.

The present invention is based on Japanese Patent Application No. 2011-278869, filed on Dec.

100‧‧‧ device

120‧‧‧carbon container

130‧‧‧ Carbon cover

140‧‧‧Baffle

145‧‧ ‧Heat-resistant dish

150‧‧‧layer of metal titanium powder

160‧‧‧Processed body

170‧‧‧Exhaust port

300‧‧‧ device

310‧‧‧Alumina container

315‧‧‧Alumina plate

320‧‧‧Titanium layer

330‧‧‧Carbon container

335‧‧‧Carbon cover

Fig. 1 is a flow chart schematically showing an example of a method for producing a highly conductive mayenite compound of the present invention.

Fig. 2 is a view schematically showing an example of the configuration of a device used for high-temperature treatment of a target object.

Fig. 3 is a view schematically showing the configuration of an apparatus used for high-temperature processing of the molded body C1 of the first embodiment.

Claims (10)

A manufacturing method characterized by being a method for producing a conductive mayenite compound, and comprising the steps of: (1) preparing a powder of a mayenite compound; and (2) supplying carbon monoxide gas and a source of titanium In the presence of the titanium vapor, the object to be treated containing the powder of the mayenite compound prepared in the above step (1) is placed in contact with the titanium source, and is subjected to an inert gas atmosphere other than nitrogen or a reduced pressure environment. Next, the object to be processed is maintained at a temperature in the range of 1230 ° C to 1380 ° C. The method of claim 1, wherein the processed system comprising the powder of the mayenite compound comprises a shaped body of the powder of the mayenite compound. The method of claim 2, wherein the processed system is configured by attaching a molded body of the powder containing the mayenite compound to a conductive member. A manufacturing method, characterized in that it is a method for producing a conductive mayenite compound, and comprises the steps of: (1) preparing a sintered body containing a mayenite compound; and (2) carbon monoxide gas and a source of titanium In the presence of the supplied titanium vapor, the object to be processed containing the sintered body containing the mayenite compound prepared in the above step (1) is placed in contact with the titanium source, and is in an inert gas atmosphere other than nitrogen. Or under reduced pressure, the above is processed The body is maintained at a temperature ranging from 1230 ° C to 1380 ° C. A manufacturing method characterized by being a method for producing a conductive mayenite compound, and comprising the steps of: (1) preparing a shaped body of a calcined powder; and (2) supplying carbon monoxide gas and a source of titanium In the presence of the titanium vapor, the object to be processed containing the formed body of the calcined powder prepared in the above step (1) is placed in contact with the titanium source, and is subjected to an inert gas atmosphere other than nitrogen or a reduced pressure environment. Next, the object to be processed is maintained at a temperature in the range of 1230 ° C to 1380 ° C. The production method according to any one of claims 1 to 5, wherein the step (2) is carried out in a state in which the object to be processed and the titanium source are placed in a container containing carbon. The production method according to any one of claims 1 to 6, wherein the conductive mayenite compound obtained after the step (2) has an electron density of 3.0 × 10 ²⁰ cm ^-3 or more. The production method according to any one of claims 1 to 7, wherein the object to be treated contains fluorine (F), and after the step (2), a conductive mayenite compound containing fluorine can be obtained. An electrode for a fluorescent lamp, comprising a conductive mayenite compound produced by the production method according to any one of claims 1 to 8. A method of producing a method for forming a film-forming target of a conductive mayenite compound by using the production method according to any one of claims 1 to 8.