JP7120544B2 - Manufacturing method and manufacturing apparatus for obtaining a product different from the compound by treating a compound containing metal atoms having a boiling point higher than that of a metal material consisting only of metal atoms with plasma - Google Patents

Description

The present invention relates to a manufacturing method and a manufacturing apparatus for obtaining a product different from the compound by treating a compound containing metal atoms having a boiling point higher than that of a metal material consisting only of metal atoms with plasma.

For example, in Patent Document 1, under reduced pressure below atmospheric pressure, anhydrous magnesium halide is exposed to plasma in a reducing gas atmosphere, and the anhydrous magnesium halide is subjected to an exothermic reaction with active species to cause anhydrous halogenation. A method for producing metallic magnesium is disclosed in which magnesium is reduced to obtain metallic magnesium.

Then, it is explained that magnesium luminescence is observed when anhydrous magnesium chloride is heated to about 700° C. or higher.

Japanese Unexamined Patent Application Publication No. 2016-216780

Therefore, when a structure capable of heating the inside of the reaction chamber to 700° C. or more is provided, a problem arises that the initial lighting of the plasma may not be successful.

The present invention has been made in view of such circumstances, and a metal atom having a boiling point higher than that of a metal material consisting only of metal atoms, which can stably start plasma lighting, is used. It is an object of the present invention to provide a manufacturing method and a manufacturing apparatus for obtaining a product different from the compound by plasma-treating the compound contained therein.

In order to achieve the above objects, the present invention is grasped by the following configurations.
(1) The production method of the present invention is a production method in which a compound containing metal atoms having a boiling point higher than that of a metal material consisting only of metal atoms is treated with plasma to obtain a product different from the compound. and generating a product different from the compound by irradiating the compound with a plasma of a reactive gas that does not substantially contain oxygen atoms in a reaction chamber at a temperature at which the compound maintains a gaseous state, When the temperature in the reaction chamber is outside the predetermined temperature range, the plasma is started to be turned on, and the predetermined temperature range is set when the pressure in the reaction chamber is the same as the pressure set in the procedure. It is in the range of not less than the boiling point of the metal material having only the metal atoms and less than the boiling point of the compound.

(2) In the configuration of (1) above, the compound is an anhydrous magnesium halide containing magnesium as the metal atom.

(3) In the configuration of (1) or (2) above, it is arranged within the range where the plasma exists in the reaction chamber, and the surface temperature is controlled within a predetermined temperature range suitable for the deposition of the product. The product is obtained by the attached means.

(4) The production apparatus of the present invention is a production apparatus for obtaining a product different from the compound by plasma-treating a compound containing metal atoms having a boiling point higher than that of a metal material consisting only of metal atoms. The manufacturing apparatus includes depressurizing means for reducing the pressure in the reaction chamber, temperature control means for maintaining the inside of the reaction chamber at a boiling point or higher of the compound, and a reactive gas that substantially does not contain oxygen atoms to be converted into plasma by the reaction chamber. gas supply means for supplying gas into the chamber; microwave generating means for generating microwaves to be supplied to the reaction chamber to generate the plasma; and a dielectric provided in the reaction chamber for injecting the microwaves and a window made of a material, wherein the microwave generating means controls the temperature in the reaction chamber so that the temperature in the reaction chamber is outside a predetermined temperature range so that the plasma can be started to be turned on. When the temperature is outside the range, the microwave can be supplied, and the predetermined temperature range is equal to or higher than the boiling point of the metal material having only the metal atoms when the pressure in the reaction chamber is set. , below the boiling point of the compound.

(5) In the configuration of (4) above, the manufacturing apparatus includes compound supply means for supplying the compound in a gaseous state into the reaction chamber; a deposition means the temperature of which is controlled within a predetermined temperature range suitable for deposition of said product.

According to the present invention, a compound containing metal atoms having a boiling point higher than that of a metal material consisting only of metal atoms, which can stably start plasma lighting, is treated with plasma to make it different from the compound. A manufacturing method and a manufacturing apparatus for obtaining a product can be provided.

5 is a graph showing the boundary between the reaction that proceeds to the right side and the reaction that proceeds to the left side of Equation 5 when the partial pressure of hydrogen atoms is changed. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing for demonstrating the manufacturing apparatus of the magnesium hydride of 1st Embodiment which concerns on this invention.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, the form (henceforth, embodiment) for implementing this invention is demonstrated in detail.
The same numbers or symbols are given to the same elements throughout the description of the embodiment.

In the following, a specific example of a manufacturing method for obtaining a product different from a compound by treating a compound containing a metal atom having a boiling point higher than that of a metal material consisting only of metal atoms with plasma will be described. A manufacturing method for obtaining magnesium hydride, which is a product different from the compound by treating anhydrous magnesium chloride (boiling point of which is about 650° C. at a pressure of about 10 Pa), which is a compound containing magnesium, with microwave surface wave hydrogen plasma will be described. .
It should be noted that the boiling point of a metal material (magnesium metal) consisting only of magnesium, which is a metal atom, is about 400° C. at a pressure of about 10 Pa.

However, the fact that magnesium hydride can be produced simply by treating anhydrous magnesium chloride with hydrogen plasma (microwave surface wave hydrogen plasma in this example) is something that cannot be understood from ordinary chemical reaction formulas. Before describing the manufacturing method and manufacturing apparatus 1 of the embodiment, the reason why a product containing magnesium hydride can be obtained will be described.

A reaction formula focusing on a reaction in which anhydrous magnesium chloride reacts with hydrogen to form magnesium hydride is generally expressed as the following formula 1.
MgCl ₂ + H ₂ ⇔ MgH ₂ + Cl ₂ (1)

The problem here is how to set the environment (pressure and temperature) during the reaction so that the right side of Equation 1 becomes stable and the reaction proceeds to the right side.

Which is the stable state can be determined by considering the Gibbs free energy. Assuming that the pressure is set to 10 Pa to generate a certain microwave surface wave hydrogen plasma, the temperature in the reaction chamber 2 (see FIG. 2) must be about 1150° C. or higher in order to advance the reaction to the right.

However, in such a high temperature state, magnesium hydride itself becomes a gaseous state, so in order to deposit it as a solid, it is necessary to lower the temperature in the reaction chamber 2, but the temperature range is lower than about 1150 ° C. In this case, the reaction on the left side of Formula 1 is dominant, so the substance that precipitates as a solid becomes anhydrous magnesium chloride, and magnesium hydride does not precipitate.

In addition, magnesium hydride begins to decompose into metallic magnesium (Mg) and hydrogen (H ₂ ) when the temperature exceeds 100°C. The concept based on Equation 1, which requires temperature, results in the magnesium hydride ( _MgH2 ) being decomposed and difficult to precipitate as magnesium hydride ( _MgH2 ).

However, considering the environment within the range where hydrogen plasma exists (within the range where the emission color of hydrogen plasma can be seen), excited atoms/molecules, radicals (chemically active atoms/molecules), electrons, ions (positive and negative) ) and neutral atoms and molecules can be assumed.

Then, for example, as an example, regarding the following formula 2 assuming a situation in which a hydrogen atom exists, considering the boundary between the reaction proceeding to the right and the reaction proceeding to the left based on Gibbs' free energy, as shown in FIG. become.
MgCl ₂ + 2H + H ₂ ⇔ MgH ₂ + 2HCl (2)

In FIG. 1, the pressure in the reaction chamber 2 (see FIG. 2) is 10 Pa, the horizontal axis is the partial pressure (mPa) of hydrogen atoms, and the vertical axis is temperature (° C.). ) is changed, the boundary between the reaction that proceeds to the right and the reaction that proceeds to the left is shown in degrees (° C.).

As can be seen from Fig. 1, when the partial pressure of hydrogen atoms is the same, _MgH2 is produced by lowering the temperature, and at the same temperature, the higher the partial pressure of hydrogen atoms, the more _MgH2 is produced. It has become so.

In other words, under a special environment within the range where hydrogen plasma exists (within the range where the emission color of hydrogen plasma can be seen), the temperature is below the temperature at which magnesium hydride (MgH ₂ ) begins to decompose (approximately 100°C). 2, the reaction of Equation 2 can proceed to the right and magnesium hydride (MgH ₂ ) can be produced as a product.

For example, when hydrogen is supplied into the reaction chamber 2 so that the pressure in the reaction chamber 2 (see FIG. 2) is about 10 Pa, the partial pressure of hydrogen atoms is considered to be about 10 mPa. Considering the partial pressure of the hydrogen atoms, the adhesion means 80 having the temperature of the surface 81 of, for example, about 85° C. or less should be placed within the range where the hydrogen plasma exists (within the range where the emission color of the hydrogen plasma can be seen). For example, it is possible to deposit magnesium hydride (MgH ₂ ) on the surface 81 of the attachment means 80 .

In the case of low-temperature plasma such as microwave surface wave hydrogen plasma, unlike thermal plasma (for example, DC plasma of inert gas), the temperature of the plasma itself is low. , the temperature of the surface 81 of the adhesion means 80 can be controlled to a low temperature.

Therefore, in the manufacturing apparatus 1 described below, while maintaining the inside of the reaction chamber 2 at a temperature at which anhydrous magnesium chloride is maintained in a gaseous state, the range in which plasma exists in the reaction chamber 2 so as to obtain magnesium hydride (hydrogen By providing an adhesion means 80 arranged within a range where the emission color of the plasma is visible) and having a surface temperature controlled to a temperature within a predetermined temperature range suitable for depositing a product containing magnesium hydride. , making it possible to obtain a product containing magnesium hydride, which is different from anhydrous magnesium chloride, which is the compound treated with the plasma.

Next, the manufacturing apparatus 1 of this embodiment will be described with reference to FIG. 2, and then the manufacturing method will be described in detail.
FIG. 2 is a cross-sectional view for explaining the manufacturing apparatus 1 of the embodiment according to the present invention.

As shown in FIG. 2, the manufacturing apparatus 1 includes a housing 10 forming a reaction chamber 2. In the present embodiment, a partition 11 having an opening 11A in the center is provided in the housing 10. The reaction chamber 2 has a first space F and a second space S.
However, this partition part 11 may be omitted, and the reaction chamber 2 may be formed as one space.

The manufacturing apparatus 1 includes a window W made of a dielectric material (for example, quartz, ceramics, etc.) provided in a portion of the reaction chamber 2 where microwaves are incident, and a reaction through the window W for generating plasma. A microwave generating means 20 (for example, a magnetron) for generating microwaves supplied to the first space F in the chamber 2, and a guide for guiding the microwave generated by the microwave generating means 20 to the window W. A wave tube 21 is provided.

In this embodiment, the frequency of the generated microwave is 2.45 GHz, but it is not necessary to be limited to this frequency. It may be 40.6 MHz, 27.1 MHz, 13.56 MHz, and the like.

Further, in the present embodiment, the microwave generating means 20 generates pulse-like microwaves, while increasing the peak value of the microwave power (microwave intensity), ) is lowered.

However, pulse-like microwaves mean those accompanied by periodic microwave power (microwave intensity), and are not necessarily limited to those whose microwave power (microwave intensity) periodically becomes zero. not to be

Specifically, the microwave generating means 20 has a period of 150 microseconds or less (preferably 100 microseconds or less, more preferably 50 microseconds or less, more preferably 50 microseconds or less) in which the peak value of the microwave power (microwave intensity) of the pulse-like microwave appears. microseconds or less), and supply microwaves having a peak microwave power into the reaction chamber 2 before the plasma (microwave surface wave hydrogen plasma in this example) is significantly attenuated. By doing so, the average power used by the microwave generating means 20 is suppressed while maintaining the microwave surface wave plasma having a density substantially corresponding to the peak value of the microwave power (microwave intensity). .

In this way, when the microwave generating means 20 generates microwaves other than pulsed microwaves with substantially constant microwave power (microwave intensity), the plasma density is 10 ¹² /cm ³ or more. If it is ¹⁴ /cm ³ or less, even if the average microwave power is the same, when the microwave generating means 20 generates pulse-like microwaves, the microwave power (microwave intensity) peak Since the value can be increased, a higher plasma density (for example, a high plasma density of 10 ¹⁵ /cm ³ or more) can be obtained, and even if the average microwave power is the same, a plasma density higher than one order of magnitude can be obtained. be able to.

Therefore, by setting the microwave generating means 20 to generate pulse-like microwaves, high-density microwave It can generate surface wave plasma.
Moreover, when the peak value of the microwave power (microwave intensity) increases, there is also the effect that it becomes easier to ignite the microwave surface wave plasma.

Microwave surface wave plasma has a low electron temperature (e.g., about 1 eV) compared to other plasmas (e.g., high-frequency plasma, DC discharge plasma, etc.), and has a high electron temperature (e.g., about 1 eV) like other plasmas. For example, there is an advantage that energy loss is small unlike plasma that consumes energy to achieve 10 eV or more.
Another feature of microwave surface wave plasma is that the temperature of the ions and molecules in the plasma is significantly lower than that of thermal plasma (almost normal temperature).
Furthermore, the microwave surface wave plasma can uniformly generate the above-described high-density plasma over a large area of, for example, 0.5 m ² or more.

The manufacturing apparatus 1 also includes a depressurizing means 30 for discharging the gas in the reaction chamber 2 and reducing the pressure in the reaction chamber 2 .
Specifically, the manufacturing apparatus 1 is a decompression means connected to the first space F through a first exhaust pipe 31 provided with a first exhaust valve 31A that determines the presence or absence of exhaust by opening/closing operation or opening/closing control. Decompression means connected to the second space S through a second exhaust pipe 33 provided with a first vacuum pump 32 as 30 and a second exhaust valve 33A that determines the presence or absence of exhaust by opening/closing operation or opening/closing control. a second vacuum pump 34 as 30;

In order to stably generate microwave surface wave hydrogen plasma, which is a high-density hydrogen plasma, it is advantageous for the pressure in the reaction chamber 2 to be low. is preferably 1/100 atmosphere or less, more preferably 1/1000 atmosphere or less, and in the present embodiment, it is set to about 10 Pa, which is about 1/10000 atmosphere.

In the case of a vacuum pump with a weak gas suction force, it takes time to increase the degree of vacuum in the reaction chamber 2. Therefore, in order to eliminate such setup time, the first vacuum pump 32 or the second vacuum pump At least one of 34 is preferably a mechanical booster pump having a high gas suction force.

The manufacturing apparatus 1 includes a first pressure gauge 32A for measuring the pressure in the first space F of the reaction chamber 2 and a second pressure gauge 32A for measuring the pressure in the second space S of the reaction chamber 2. A total 34A is provided, for example, based on the pressure measured by the first pressure gauge 32A, so that the pressure in the first space F becomes a predetermined pressure (for example, about 10 Pa). The operations of the pump 32 and the first exhaust valve 31A may be controlled.
For example, the first vacuum pump 32 may be operated and the operation of the first exhaust valve 31A may be controlled based on the pressure measured by the first pressure gauge 32A.

Similarly, for example, based on the pressure measured by the second pressure gauge 34A, the second vacuum pump 34 and the second exhaust valve are adjusted so that the pressure in the second space S becomes a predetermined pressure (for example, about 10 Pa). You may make it control the operation|movement of 33A.
For example, the operation of the second exhaust valve 33A may be controlled based on the pressure measured by the second pressure gauge 34A while the second vacuum pump 34 is in operation.

However, it is not necessary to control both the two vacuum pumps (the first vacuum pump 32 and the second vacuum pump 34) in order to set the pressures in the first space F and the second space S to predetermined pressures.

For example, as a preliminary setup, the two vacuum pumps (the first vacuum pump 32 and the second vacuum pump 34) are operated only when the pressure in the reaction chamber 2 is set to a predetermined pressure, and the pressure in the reaction chamber 2 is set to a predetermined pressure. When the pressure reaches , the first exhaust valve 31A is closed to stop the operation of the first vacuum pump 32, and thereafter, based on the pressure measured by the first pressure gauge 32A or the second pressure gauge 34A, the reaction The operations of the second vacuum pump 34 and the second exhaust valve 33A may be controlled so as to maintain the pressure inside the chamber 2 at a predetermined pressure.

As the measured value of the pressure in the reaction chamber 2 used when maintaining the pressure in the reaction chamber 2 at a predetermined pressure, the pressures measured by the first pressure gauge 32A and the second pressure gauge 34A were averaged. You may make it use a thing.

The manufacturing apparatus 1 also includes a gas supply means (not shown) for supplying a reactive gas containing substantially no plasmatized oxygen atoms into the reaction chamber 2 .

In this embodiment, hydrogen is used as the reactive gas that causes the reduction reaction, but the reactive gas is not limited to hydrogen because the reduction reaction can be caused by methane, propane, or the like.

Therefore, hereinafter, the gas supply means is referred to as hydrogen supply means, but the hydrogen supply means is only an example of the gas supply means.

If oxygen atoms are contained, the reduction reaction is inhibited. The expression "substantially free of oxygen atoms" means that oxygen atoms are not contained in excess of the moisture contained at the level of the high-purity gas.

For example, the hydrogen supply means includes a hydrogen storage unit (hydrogen cylinder or hydrogen storage tank) (not shown) serving as a hydrogen supply source, and a mass flow controller or the like that controls the amount of hydrogen supplied from the hydrogen storage unit to the reaction chamber 2. Controllers (first flow controller MFC1 and second flow controller MFC2).
However, if the hydrogen storage unit is a cylinder, the hydrogen supply means may be a portion other than the hydrogen storage unit because it will be detached for replacement.

Specifically, the hydrogen storage unit is connected so that hydrogen can be supplied to the first space F through the first supply pipe 41, and hydrogen is supplied to the second space S through the second supply pipe 42. A first flow rate controller MFC1 is provided on the hydrogen storage unit side of the first supply pipe 41, and a first supply valve 41A that determines whether or not to supply by opening/closing operation or opening/closing control is provided on the downstream side. ing.

Similarly, a second flow rate controller MFC2 is provided on the side of the hydrogen storage section of the second supply pipe 42, and a second supply valve 42A is provided on the downstream side thereof to determine the presence or absence of supply by opening/closing operation or opening/closing control.

Furthermore, the manufacturing apparatus 1 has a boiling point (at a pressure of about 10 Pa) higher than the boiling point (about 400 ° C. at a pressure of about 10 Pa) of a metal material (magnesium metal in this example) consisting only of metal atoms (magnesium atoms in this example) compound supply means for supplying anhydrous magnesium chloride, which is a compound containing a metal atom having a temperature of about 650° C., into the reaction chamber 2 (more specifically, into the first space F of the reaction chamber 2) in a gaseous state. It has 50.

Specifically, the compound supply means 50 includes a compound storage unit 51 that stores anhydrous magnesium chloride, which is a compound to be treated with plasma, and an anhydrous magnesium chloride in the compound storage unit 51 that is supplied to the first space F of the reaction chamber 2. A compound supply pipe 52 for supplying power to, a first heating unit 53 that heats the compound supply pipe 52 and the compound storage unit 51 by supplying power from the first power supply 53A, and the temperature of the first heating unit 53 and a first thermometer 54 for measuring.

Then, the amount of electric power supplied from the first power supply 53A to the first heating unit 53 is controlled so that the temperature measurement result by the first thermometer 54 becomes the set predetermined temperature, and the compound supply pipe 52 and compound reservoir 51 are heated to a predetermined temperature.

When the compound to be treated with plasma is anhydrous magnesium chloride as in the present embodiment, the compound supply pipe 52 and the compound storage unit 51 are heated by the first heating unit 53 so that the anhydrous magnesium chloride is in a gaseous state. Heat to a temperature of about 700°C.
Then, the vaporized anhydrous magnesium chloride flows into the first space F of the reaction chamber 2 and is supplied into the first space F.

In addition, the manufacturing apparatus 1 is arranged such that the inside of the reaction chamber 2 is heated to a temperature higher than the boiling point of the compound (in this example, anhydrous magnesium chloride) (the boiling point is about 650° C. when the pressure inside the reaction chamber 2 is about 10 Pa). A temperature control means 60 is provided to maintain the temperature.

Specifically, the temperature control means 60 is provided in the first space F of the reaction chamber 2 , and includes a second heating section 61 that heats the inside of the reaction chamber 2 and a second heating section 61 that supplies power to the second heating section 61 . A power source 61A and a second thermometer 62 for measuring the temperature in the first space F of the reaction chamber 2 are provided.

Then, the manufacturing apparatus 1 controls the amount of power supplied from the second power source 61A to the second heating unit 61 so that the result of temperature measurement by the second thermometer 62 becomes a predetermined set temperature. Then, the temperature in the first space F of the reaction chamber 2 is kept at a predetermined temperature.

In this embodiment, the temperature control means 60 keeps the temperature in the reaction chamber 2 at about 700° C., which is the temperature at which the compound to be treated with the plasma, anhydrous magnesium chloride, is kept in a gaseous state.
Since the boiling point of anhydrous magnesium chloride at a pressure of about 10 Pa is about 650° C., in the present embodiment, the boiling point is maintained at about 700° C., which is higher than the boiling point. When the set pressure is changed, the set temperature set in the temperature control means 60 is changed correspondingly.
In the present embodiment, anhydrous magnesium chloride is used, but magnesium fluoride or the like may also be used, and the set temperature set in the temperature control means 60 will be changed according to the difference in compounds.

On the other hand, on the outside of the second heating unit 61, in order to prevent the housing 10 from becoming hot due to the radiant heat from the second heating unit 61, a reflector 70 that reflects the radiant heat is provided. Cooling pipes 71 for water cooling are provided on the outer surface.

As described above, when the manufacturing apparatus 1 is provided with heat insulating means such as the reflector 70 that prevents heat conduction so that the second heating unit 61 does not heat an excessive portion, the temperature of the housing 10 does not become high. Not only can the deterioration of packings and the like used in various parts of the body 10 be suppressed, but also the heat insulation efficiency can be improved, so that power consumption can be reduced.

In addition, the reflector 70 is provided with an insertion tube 72 that is inserted from the first space F into the second space S through the opening 11A of the partition 11 at a position near the center on the upper side. As will be described later, gas containing hydrogen plasma and magnesium is discharged from the insertion tube 72 into the second space S.

Then, as shown in FIG. 2, the manufacturing apparatus 1 is provided with a depositing means 80 for depositing a magnesium product containing magnesium hydride at a position facing the insertion tube 72. After stopping the manufacturing apparatus 1, The adhesion means 80 is detachably attached to the housing 10 so that the adhesion means 80 can be taken out.

As mentioned earlier, the microwave surface wave plasma is characterized in that the temperature of the ions and molecules in the plasma is much lower (almost normal temperature) than the plasma called thermal plasma. By locating the surface 81 near the insertion tube 72, even if it is arranged within the range where the plasma in the reaction chamber 2 exists (within the range where the emission color of the hydrogen plasma can be seen), it can be easily detected as described below. With this structure, the surface temperature of the adhesion means 80 (the temperature of the surface 81) can be set to a surface temperature at which magnesium hydride can be deposited as a solid.

The adhesion means 80 has a medium supply port IN for supplying a temperature control medium (for example, outside air as a coolant) and a medium discharge port OUT for discharging the temperature control medium. It has a sealed container structure that prevents leakage to S.

In the adhesion means 80, the surface 81 on which the magnesium product containing magnesium hydride is adhered on the side facing the insertion tube 72 is exposed to high-density hydrogen plasma that allows the luminous state emitted from the insertion tube 72 to be visually confirmed. By arranging them in direct contact, they are arranged within the range where the generated hydrogen plasma exists.

The manufacturing apparatus 1 includes medium supply means (for example, a fan, a compressor, etc.) (not shown) for supplying outside air, which serves as a temperature control medium, from the medium supply port IN into the adhesion means 80. The surface temperature of the surface 81 onto which the magnesium product containing magnesium hydride of 80 is deposited is controlled within a predetermined temperature range suitable for deposition of the product containing magnesium hydride.
Incidentally, when the outside air is used as the temperature control medium as described above, the piping may be connected so that the medium outlet OUT is open to the atmosphere.

On the other hand, when using, for example, a CFC substitute as the temperature control medium, the CFC substitute discharged from the medium discharge port OUT is compressed by the compressor, and the compressed CFC substitute is reintroduced from the medium supply port IN. A cooling system (same as a so-called refrigerator, etc.) may be used.

In this case, the medium supply means includes a pump or the like for supplying the temperature control medium to the medium supply port IN through the compressor and for circulating the temperature control medium discharged from the medium discharge port OUT back to the compressor. Used.

For example, the predetermined temperature at which magnesium hydride precipitates is preferably 200° C. or lower, more preferably 150° C. or lower, and even more preferably 100° C. or lower, because the amount of precipitation significantly decreases when the temperature exceeds 200° C.

In an experiment, in the case of a product containing magnesium hydride deposited at a surface temperature exceeding 200° C., water droplets were dropped on the product, and it was confirmed that the foaming phenomenon accompanying the separation of hydrogen was very weak.

On the other hand, in the case of a product containing magnesium hydride deposited at a surface temperature of 100°C or less, it was confirmed that when water droplets were dropped, a violent foaming phenomenon accompanied by hydrogen separation was observed. A hydrogen detector tube is used to confirm that the is hydrogen.

In addition, when the surface temperature exceeds 100 ° C., a reaction in which magnesium hydride decomposes into hydrogen and metallic magnesium also occurs, so the proportion of magnesium hydride in the product containing precipitated magnesium hydride will decrease. Therefore, the predetermined temperature at which magnesium hydride precipitates is most preferably 100° C. or lower.

In addition, in the experiment, the amount of precipitation per unit time of the product containing magnesium hydride is larger at about 70°C than when the surface temperature is about 80°C, and the amount of precipitation per unit time is further at about 50°C. Therefore, it is preferable that the surface temperature is controlled within a temperature range of 80° C. or less, 70° C. or less, and more preferably 50° C. or less from the viewpoint of the precipitation amount.

Further, the manufacturing apparatus 1 is provided with an air release pipe 90 provided with a leak valve 91 in the middle thereof, and one end (not shown) of the air release pipe 90 is open to the atmosphere outside the building in which the manufacturing apparatus 1 is installed. ing.

This atmospheric release pipe 90 is for opening the reaction chamber 2 to the atmosphere as an emergency measure when the pressure in the reaction chamber 2 becomes abnormal, and the leak valve 91 is normally closed. , so that the air does not enter the reaction chamber 2 .

Next, the manufacturing method of this embodiment will be specifically described.
First, as a preliminary setup, the decompression means 30 (the first vacuum pump 32 and the second vacuum pump 34) is driven to reduce the pressure in the reaction chamber 2 to a predetermined pressure (for example, about 10 Pa). carry out the procedure for

Then, in the reaction chamber 2 at a temperature at which anhydrous magnesium chloride, which is a compound, maintains a gaseous state, plasma of hydrogen, which is a reactive gas that does not substantially contain oxygen atoms in the compound, is irradiated to produce magnesium hydride that is different from the compound. However, when the temperature in the reaction chamber 2 is outside the predetermined temperature range, after starting the plasma, the reaction chamber of anhydrous magnesium chloride, which is a compound A procedure is performed to start feeding to 2 to produce a product different from the compound.

Specifically, during the procedure for producing a product containing magnesium hydride, the temperature in the reaction chamber 2 is maintained at about 700° C., which is the temperature at which the anhydrous magnesium chloride compound can be kept in a gaseous state. .

Therefore, basically, the inner wall surface of the reaction chamber 2 is higher than about 400° C., which is the precipitation temperature of metallic magnesium, so that metallic magnesium is less likely to adhere to the inner wall surface of the reaction chamber 2 .

However, when a part of the inner wall surface of the reaction chamber 2 has a temperature lower than about 400° C. or when the temperature in the reaction chamber 2 is lowered to finish the procedure for producing a product containing magnesium hydride. For example, metallic magnesium may deposit (attach) to the inner wall surface of the reaction chamber 2 .

Then, if metal magnesium adheres to the inner wall surface of the reaction chamber 2 in the previous manufacturing process, it will adhere to the inner wall surface when the temperature of the reaction chamber 2 is increased in the next manufacturing process. When the temperature of the magnesium metal reaches 400° C. or higher, which is the boiling point, the magnesium metal becomes gaseous, and the reaction chamber 2 may be filled with high-concentration magnesium metal.

Here, since metallic magnesium has a property of reflecting microwaves (generally, simple metals often reflect microwaves), the reaction chamber 2 is filled with a high concentration of metallic magnesium. Even if the supply of microwaves into the reaction chamber 2 is started in this state, the microwaves are reflected and cannot sufficiently penetrate into the reaction chamber 2 through the window W, so that the plasma is not ignited.

On the other hand, when metallic magnesium adheres to the inner wall surface of the reaction chamber 2, it is considered that anhydrous magnesium chloride also adheres. Since it becomes a gas, the inside of the reaction chamber 2 is filled with a mixed gas of metallic magnesium and anhydrous magnesium chloride.
Then, since the concentration of metallic magnesium is lowered, a sufficient amount of microwaves can enter the reaction chamber 2 through the window W, and the plasma can be turned on.

That is, the temperature in the reaction chamber 2 is set at the temperature of the metal material (magnesium metal in this example) consisting only of the metal atoms of the compound containing metal atoms (magnesium in this example) (anhydrous magnesium chloride in this example). Within a predetermined temperature range above the boiling point at the same pressure as the pressure in the reaction chamber 2 (approximately 10 Pa in this example) (in this example, approximately 400°C or above) and below the boiling point of the compound (in this example, below approximately 650°C) Plasma lighting can be stably started by avoiding the temperature, that is, when the temperature is outside the predetermined temperature range.

Therefore, when the pressure in the reaction chamber 2 reaches a predetermined pressure (for example, about 10 Pa), the supply of the reactive gas that turns into plasma is started in the reaction chamber 2, and before the temperature control means 60 is driven, microwaves are generated. Even if the generation means 20 starts supplying microwaves or the temperature control means 60 is driven, the temperature outside the predetermined temperature range (in this example, about 400 ° C. or more and about 650 ° C. or less ), the microwave generating means 20 starts to supply microwaves.

For example, for this purpose, the manufacturing apparatus 1 is provided with an interlock that can drive the temperature control means 60 only after the microwave generating means 20 starts supplying microwaves, or the manufacturing apparatus 1 is provided with a predetermined A temperature setting mechanism for setting the temperature range is provided, and when the temperature in the first space F of the reaction chamber 2 measured by the second thermometer 62 is within the predetermined temperature range, the microwave of the microwave generating means 20 By providing an interlock that prevents the supply of , the microwave generating means 20 can reliably start supplying microwaves when the temperature in the reaction chamber 2 is outside the predetermined temperature range, When the temperature inside the reaction chamber 2 is outside the predetermined temperature range, the plasma can be started to be turned on.

After confirming the start of plasma lighting and when the temperature in the reaction chamber 2 reaches a temperature at which the anhydrous magnesium chloride, which is a compound, can be maintained in a gaseous state, the compound is supplied by the compound supply means 50. In the reaction chamber 2 at a temperature at which the compound is maintained in a gaseous state, the compound is irradiated with a plasma of a reactive gas that does not substantially contain oxygen atoms to produce a product different from the compound. , the step of depositing the product produced in the procedure on the surface 81 of the deposition means 80 whose surface temperature is controlled to within a predetermined temperature range suitable for deposition of the product.

Thus, in the manufacturing apparatus 1 of the present embodiment, the metal atoms are added to the boiling point of the metal material having only metal atoms when the pressure in the reaction chamber 2 is the same as the pressure in the reaction chamber 2 for which the temperature in the reaction chamber 2 is set. When the temperature in the reaction chamber 2 is outside the predetermined temperature range, the microwave generating means 20 can start to turn on the plasma when it is outside the predetermined temperature range which is the range below the boiling point of the containing compound. Since it is designed to start supplying microwaves, it is possible to avoid plasma failure.

In addition, even in the manufacturing method, the metal material having only metal atoms when the temperature in the reaction chamber 2 is the same as the pressure in the reaction chamber 2 set during the procedure for producing a product different from the compound Since the ignition of the plasma is started when the temperature is outside the predetermined temperature range, which is the boiling point of the metal atom or more and the boiling point of the compound containing the metal atom, it is possible to prevent the plasma from being turned off properly.

Although the present invention has been described above based on specific embodiments, the present invention is not limited to the above specific embodiments.
For example, in the above embodiment, the case where anhydrous magnesium chloride was used as the compound was explained, but the compound to be treated with plasma to obtain a product containing magnesium hydride may be anhydrous magnesium halide.

In addition to obtaining a product containing magnesium hydride, a product different from a compound is obtained by treating a compound containing metal atoms having a boiling point higher than that of a metal material consisting only of metal atoms with plasma. It is conceivable that the same would occur.

Therefore, in the above description, the case where anhydrous magnesium chloride, which is a compound containing magnesium, which is a metal atom, is treated with microwave surface wave hydrogen plasma to obtain magnesium hydride, which is a product different from the compound, was described, but the present invention is limited to this. not to be

As described above, the present invention is not limited to specific embodiments, and suitable modifications and improvements are also included in the technical scope of the present invention. is clear from the description of the claims.

1 manufacturing apparatus 2 reaction chamber 10 housing 11 partition 11A opening 20 microwave generating means 21 waveguide 30 decompression means 31 first exhaust pipe 31A first exhaust valve 32 first vacuum pump 32A first pressure gauge 33 second Exhaust pipe 33A Second exhaust valve 34 Second vacuum pump 34A Second pressure gauge 41 First supply pipe 41A First supply valve 42 Second supply pipe 42A Second supply valve 50 Compound supply means 51 Compound storage section 52 Compound supply pipe 53 First heating section 53A First power supply 54 First thermometer 60 Temperature control means 61 Second heating section 61A Second power supply 62 Second thermometer 70 Reflector 71 Cooling pipe 72 Insertion pipe 80 Adhesion means 81 Surface 90 Atmospheric release pipe 91 Leakage Valve F First space IN Medium supply port MFC1 First flow controller MFC2 Second flow controller OUT Medium outlet S Second space W Window

Claims (5)

A production method for obtaining a product different from the compound by plasma-treating a compound containing a metal atom having a boiling point higher than that of a metal material consisting only of metal atoms,
irradiating the compound with a plasma of a reactive gas substantially free of oxygen atoms in a reaction chamber at a temperature at which the compound remains in a gaseous state to produce a product different from the compound;
When the temperature in the reaction chamber is outside a predetermined temperature range, the plasma is started to be turned on,
The predetermined temperature range is a range that is equal to or higher than the boiling point of the metal material having only the metal atoms and lower than the boiling point of the compound when the pressure in the reaction chamber is the same as the pressure set in the procedure. manufacturing method. 2. The production method according to claim 1, wherein the compound is anhydrous magnesium halide, which is a compound containing magnesium as the metal atom. The product is obtained by a depositing means arranged within the plasma in the reaction chamber and having a surface temperature controlled within a predetermined temperature range suitable for deposition of the product. The manufacturing method according to claim 1 or 2, wherein A production apparatus for obtaining a product different from the compound by plasma-treating a compound containing the metal atom having a boiling point higher than that of a metal material consisting only of metal atoms,
The manufacturing apparatus is
decompression means for decompressing the inside of the reaction chamber;
temperature control means for maintaining the inside of the reaction chamber above the boiling point of the compound;
gas supply means for supplying a reactive gas substantially free of plasmatized oxygen atoms into the reaction chamber;
microwave generating means for generating microwaves to be supplied into the reaction chamber to generate the plasma;
a dielectric material window provided in the reaction chamber for allowing the microwave to enter;
When the temperature in the reaction chamber is outside the predetermined temperature range, the microwave generating means generates the microwave when the temperature in the reaction chamber is outside the predetermined temperature range so that the plasma can be started to be turned on. We are ready to start supplying
The manufacturing apparatus, wherein the predetermined temperature range is a range from the boiling point of the metal material containing only the metal atoms to the boiling point of the compound at the same pressure as the set pressure in the reaction chamber. The manufacturing apparatus is
a compound supply means for supplying the compound in a gaseous state into the reaction chamber;
and a depositing means arranged within the range in which the plasma exists in the reaction chamber, the surface temperature of which is controlled within a predetermined temperature range suitable for deposition of the product. 5. The manufacturing apparatus according to 4.

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