JP2020029388A - Method and apparatus for plasma-treating compound containing metal atom having boiling point higher than boiling point of metal material consisting only of metal atom to obtain product different from compound - Google Patents

Abstract

To provide a method for plasma-treating a compound containing metal atom having a boiling point higher than a boiling point of a metal material consisting only of metal atoms to obtain a product different from the compound, wherein the lighting of plasma can be stably started.SOLUTION: The present invention provides a method for plasma-treating a compound containing metal atom having a boiling point higher than a boiling point of a metal material consisting only of metal atoms to obtain a product different from the compound. The method comprises a procedure of generating the product different from the compound by irradiating the compound with a plasma of a reactive gas that does not substantially contain an oxygen atom in a reaction chamber set at a temperature at which the compound is kept in a gaseous state. The lighting of plasma is started when the temperature in the reaction chamber is outside a predetermined temperature range. The predetermined temperature range is within a range that is not less than the boiling point of the metal material having only metal atoms at the same pressure as the pressure in the reaction chamber set in the procedure and is less than the boiling point of the compound.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus 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 of only metal atoms with plasma.

  For example, Patent Document 1 discloses that an anhydrous magnesium halide is exposed to plasma in a reducing gas atmosphere under a reduced pressure of an atmospheric pressure or less and an anhydrous magnesium halide is caused to undergo an exothermic reaction by an active species. A method for producing metal magnesium by reducing magnesium to obtain metal magnesium is disclosed.

  Further, it is described that when the heating of the anhydrous magnesium chloride proceeds to about 700 ° C. or more, magnesium emission is observed.

JP-A-2006-216780

  Therefore, when a configuration capable of heating the reaction chamber to 700 ° C. or higher is provided, there is a problem that the first lighting of the plasma may not be successful.

  The present invention has been made in view of the above circumstances, and it is possible to stably start plasma lighting, and to use a metal atom having a boiling point higher than the boiling point of a metal material consisting of only metal atoms. It is an object of the present invention to provide a production method and a production apparatus for obtaining a product different from a compound by treating a compound containing the same with plasma.

The present invention is grasped by the following configurations in order to achieve the above object.
(1) The production method of the present invention is a production method in which a compound containing a metal atom 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. A step of irradiating the compound with a plasma of a reactive gas containing substantially no oxygen atoms in a reaction chamber at a temperature where the compound maintains a gaseous state, thereby producing a product different from the compound. When the temperature in the reaction chamber is out of the predetermined temperature range, the plasma lighting is started, 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 the boiling point of the metal material having only the metal atom or higher and lower than the boiling point of the compound.

(2) In the constitution of the above (1), the compound is anhydrous magnesium halide which is a compound containing magnesium as the metal atom.

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

(4) The production apparatus of the present invention is a production apparatus that obtains a product different from the compound by treating a compound containing a metal atom having a boiling point higher than that of a metal material consisting of only metal atoms with plasma. A pressure reducing unit configured to reduce the pressure in the reaction chamber, a temperature control unit configured to maintain the reaction chamber at a temperature equal to or higher than the boiling point of the compound, and a reaction gas substantially free of oxygen atoms to be converted into plasma. Gas supply means for supplying a gas to a chamber, microwave generation means for generating a microwave to be supplied to the reaction chamber to generate the plasma, and a dielectric material provided in the reaction chamber for receiving the microwave A window made of a material, and when the temperature in the reaction chamber is out of a predetermined temperature range, the microwave generation means is configured to start lighting the plasma. The microwave can be started to be supplied when the temperature is outside a predetermined temperature range, and the predetermined temperature range has only the metal atoms at the same pressure as the set pressure in the reaction chamber. It is in the range from the boiling point of the metal material to the boiling point of the compound.

(5) In the configuration of (4), the production apparatus is provided with a compound supply unit that supplies the compound in a gaseous state into the reaction chamber, and is disposed within a range where the plasma exists in the reaction chamber, A deposition means whose temperature is controlled to a temperature within a predetermined temperature range suitable for the precipitation of the product.

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

10 is a graph showing a boundary between a reaction that proceeds to the right side and a reaction that proceeds to the left side of Equation 5 when the partial pressure of a hydrogen atom is changed. It is a sectional view for explaining a manufacturing device of magnesium hydride of a 1st embodiment concerning the present invention.

Hereinafter, embodiments for implementing the present invention (hereinafter, embodiments) will be described in detail with reference to the accompanying drawings.
The same elements are denoted by the same reference numerals or symbols throughout the description of the embodiments.

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

  However, the fact that magnesium hydride can be produced only by treating anhydrous magnesium chloride with hydrogen plasma (in this example, microwave surface wave hydrogen plasma) cannot be understood from a normal chemical reaction formula. Before explaining the manufacturing method and the manufacturing apparatus 1 of such an embodiment, the reason why a product containing magnesium hydride can be obtained will be described.

Normally, a reaction formula focusing on a reaction between anhydrous magnesium chloride and hydrogen to form magnesium hydride is represented by the following formula 1.
MgCl ₂ + H ₂ ⇔ MgH ₂ + Cl ₂ (1)

  Here, the problem is how to set the environment (pressure and temperature) during the reaction, where the right side in Equation 1 is in a stable state and the reaction proceeds to the right side.

  Which is in a stable state can be understood by considering the free energy of Gibbs. In the case of Equation 1, the pressure in the reaction chamber 2 for performing the plasma reaction is increased by hydrogen plasma having a high density and a low electron temperature. 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) needs to be about 1150 ° C. or higher in order to proceed the reaction to the right.

  However, in such a high temperature state, magnesium hydride itself is in a gaseous state. Therefore, in order to deposit magnesium hydride as a solid, it is necessary to lower the temperature in the reaction chamber 2. In this case, the reaction on the left side of the formula 1 becomes dominant, so that the substance precipitated as a solid becomes anhydrous magnesium chloride, and magnesium hydride does not precipitate.

Also, since magnesium hydride starts to decompose into metallic magnesium (Mg) and hydrogen (H ₂ ) when the temperature exceeds 100 ° C., even from this point, in order to advance the reaction to the right, the inside of the furnace at about 1150 ° C. or more is required. The concept based on Equation 1, which requires temperature, results in magnesium hydride (MgH ₂ ) being decomposed and difficult to precipitate as magnesium hydride (MgH ₂ ).

  However, considering the environment within the range in which the hydrogen plasma is present (where the emission color of the hydrogen plasma is visible), excited atoms / molecules, radicals (chemically active atoms / molecules), electrons, ions (positive and negative) ) And the presence of neutral atoms and molecules.

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

  FIG. 1 shows that the pressure in the reaction chamber 2 (see FIG. 2) is 10 Pa, the horizontal axis represents the partial pressure of hydrogen atoms (mPa), the vertical axis represents the temperature (° C.), and the partial pressure of hydrogen atoms (mPa). ) Is a graph showing how many degrees (° C.) the boundary between a reaction proceeding to the right and a reaction proceeding to the left becomes in the case where () is changed.

As can be seen from FIG. 1, when the partial pressure of hydrogen atoms is the same, MgH ₂ is generated by lowering the temperature. At the same temperature, the higher the partial pressure of hydrogen atoms, the more MgH ₂ is generated. It has become so.

In other words, under a special environment in a range where hydrogen plasma exists (a range in which the emission color of hydrogen plasma can be seen), the temperature is lower than the temperature (about 100 ° C.) at which decomposition of magnesium hydride (MgH ₂ ) starts. Nevertheless, the reaction of Equation 2 proceeds 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 of the reaction chamber 2 (see FIG. 2) becomes about 10 Pa, the partial pressure of hydrogen atoms is considered to be about 10 mPa. According to the partial pressure of the hydrogen atoms, the attaching means 80 in which the temperature of the surface 81 is set to, for example, about 85 ° C. or less is arranged in a range where the hydrogen plasma exists (a range in which the emission color of the hydrogen plasma can be seen). For example, magnesium hydride (MgH ₂ ) can be deposited on the surface 81 of the attaching means 80.

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

  Therefore, in the manufacturing apparatus 1 described below, the temperature within the reaction chamber 2 is maintained at a temperature at which anhydrous magnesium chloride maintains a gaseous state, and the temperature within the range where the plasma in the reaction chamber 2 exists (hydrogen) so that magnesium hydride is obtained. The emission means is arranged within a range in which the emission color of the plasma can be visually observed), and the attachment temperature is controlled to a temperature within a predetermined temperature range suitable for depositing a product containing magnesium hydride. Thus, it is possible to obtain a product containing magnesium hydride different from anhydrous magnesium chloride which is a compound to be treated with plasma.

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

As illustrated in FIG. 2, the manufacturing apparatus 1 includes a housing 10 that forms the reaction chamber 2. In the present embodiment, a partition 11 having an opening 11 </ b> A in the center is provided in the housing 10. The reaction chamber 2 has a first space F and a second space S.
However, the partition 11 may be omitted, and the reaction chamber 2 may be formed as one space.

  Then, the manufacturing apparatus 1 reacts with a window W made of a dielectric material (for example, quartz or ceramics) provided at a portion of the reaction chamber 2 where microwaves are incident, through the window W to generate plasma. A microwave generating means 20 (for example, a magnetron) for generating a microwave supplied to the first space F in the chamber 2 and a waveguide for guiding the microwave generated by the microwave generating means 20 to the window W And a wave tube 21.

  In the present embodiment, the frequency of the generated microwave is set to 2.45 GHz. However, the frequency is not limited to this frequency. For example, 24.1 GHz, 5 GHz, 915 MHz, and ISM bands that can be used for purposes other than communication purposes. 40.6 MHz, 27.1 MHz, 13.56 MHz, etc.

  Further, in the present embodiment, the microwave generation means 20 generates a pulse-like microwave and increases the peak value of the microwave power (microwave intensity) while increasing the average microwave power (microwave intensity). ).

  However, pulse-like microwaves mean those with periodic microwave power (microwave intensity), and are not necessarily limited to those with periodic microwave power (microwave intensity) zero. It is not done.

  Specifically, the microwave generation means 20 determines that the period at which the peak value of the microwave power (microwave intensity) of the pulsed microwave appears is 150 microseconds or less (preferably 100 microseconds or less, more preferably 50 microseconds or less). A microwave having a microwave power of a peak value is supplied into the reaction chamber 2 before the plasma (microwave surface wave hydrogen plasma in this example) is greatly attenuated. By doing so, the average power used in the microwave generation means 20 is suppressed while maintaining a 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 generation means 20 generates a microwave which is not a pulsed microwave with a substantially constant microwave power (microwave intensity), the plasma density is not less than 10 ¹² / cm ^{3 and not} more than 10 ¹² / cm ^3. If the microwave power is equal to or less than ¹⁴ / cm ³ , even if the average microwave power is the same, when the microwave generation means 20 generates a pulse-like microwave, the peak of the microwave power (microwave intensity) is obtained. Since the value can be increased, a higher plasma density (for example, a higher plasma density of 10 ¹⁵ / cm ³ or more) can be obtained, and even if the average microwave power is made similar, a plasma density higher by one digit or more can be obtained. be able to.

Therefore, the microwave generation means 20 generates pulsed microwaves, thereby suppressing an increase in the amount of electric power (average power) used in the microwave generation means 20 and increasing the density of the microwaves. Surface wave plasma can be generated.
Further, when the peak value of the microwave power (microwave intensity) increases, there is also an effect that the microwave surface wave plasma is easily ignited.

The microwave surface wave plasma has a lower electron temperature (for example, about 1 eV) and a higher electron temperature (for example, about 1 eV) than other plasmas (for example, high-frequency plasma or DC discharge plasma). For example, unlike plasma in which energy is consumed for setting to 10 eV or more), there is an advantage that energy loss is small.
Microwave surface wave plasma also has a feature that the temperature of ions and molecules in the plasma is significantly lower (almost at room temperature) than that of thermal plasma.
Further, the microwave surface wave plasma can uniformly generate the high-density plasma as described above, for example, in a large area of 0.5 m ² or more.

In addition, the manufacturing apparatus 1 includes a decompression unit 30 that discharges gas from the reaction chamber 2 and decompresses the inside of the reaction chamber 2.
Specifically, the manufacturing apparatus 1 includes a decompression unit connected to the first space F via a first exhaust pipe 31 provided with a first exhaust valve 31A that determines the presence or absence of exhaust by an opening / closing operation or opening / closing control on the way. Decompression means connected to the second space S via a first vacuum pump 32 as a unit 30 and a second exhaust pipe 33 provided with a second exhaust valve 33A for determining the presence or absence of exhaust by an opening / closing operation or opening / closing control on the way. 30 as a second vacuum pump 34.

  In order to stably generate microwave surface wave hydrogen plasma, which is high-density hydrogen plasma, it is advantageous that the pressure in the reaction chamber 2 is low, and at least the pressure in the reaction chamber 2 is 1/10 atm or less. The pressure is preferably 1/100 atm or less, more preferably 1/1000 atm or less. In the present embodiment, the pressure is set at about 10 Pa, which is about 1 / 10,000 atm.

  In the case of a vacuum pump having 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 is required. It is preferable that at least one of the 34 is a mechanical booster pump having a high gas suction force.

The manufacturing apparatus 1 has a first pressure gauge 32A for measuring the pressure in the first space F of the reaction chamber 2 and a second pressure gauge for measuring the pressure in the second space S of the reaction chamber 2. And a total vacuum 34A, 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 set so that the pressure in the second space S becomes a predetermined pressure (for example, about 10 Pa). The operation of 33A may be controlled.
For example, the second vacuum pump 34 may be operated, and the operation of the second exhaust valve 33A may be controlled based on the pressure measured by the second pressure gauge 34A.

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

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

  In addition, as a 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 pressure measured by the first pressure gauge 32A and the second pressure gauge 34A was averaged. A thing may be used.

  In addition, the manufacturing apparatus 1 includes a gas supply unit (not shown) for supplying a reactive gas substantially not containing oxygen atoms to be converted into plasma into the reaction chamber 2.

  In the present embodiment, hydrogen is used as a reactive gas that causes a reduction reaction. However, the reactive gas is not limited to hydrogen because methane, propane, or the like can cause a reduction reaction.

  For this reason, hereinafter, the gas supply unit is referred to as a hydrogen supply unit, but the hydrogen supply unit is merely an example of the gas supply unit.

  Then, if an oxygen atom is contained, the reduction reaction is inhibited, but even a very high-purity gas having a low dew point contains a trace amount of water, so that it is not completely free from oxygen atoms, and therefore, The term "substantially free of oxygen atoms" means that oxygen atoms are not contained more than water contained at the level of 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 flow rate of a mass flow controller or the like for controlling the supply amount of hydrogen supplied from the hydrogen storage unit to the reaction chamber 2. And a controller (a first flow controller MFC1 and a second flow controller MFC2).
However, when the hydrogen storage unit is a cylinder, it is attached and detached for replacement, and thus the hydrogen supply unit may be a part other than the hydrogen storage unit.

  Specifically, the hydrogen storage unit is connected so that hydrogen can be supplied to the first space F via the first supply pipe 41 and supplies hydrogen to the second space S via the second supply pipe 42. A first flow controller MFC1 is provided on the hydrogen storage side of the first supply pipe 41, and a first supply valve 41A is provided downstream of the first supply pipe 41 to determine the presence or absence of supply by opening / closing operation or opening / closing control. ing.

  Similarly, a second flow controller MFC2 is provided on the hydrogen storage side of the second supply pipe 42, and a second supply valve 42A is provided downstream of the second flow control device MFC2 for determining whether or not supply is performed by opening and closing operation or opening and closing control.

  Furthermore, the manufacturing apparatus 1 has a boiling point (at a pressure of about 10 Pa) that is higher than the boiling point (at about 10 Pa at a pressure of about 400 ° C.) of a metal material (a metal magnesium in this example) consisting of only metal atoms (a magnesium atom 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, in the first space F of the reaction chamber 2) in a gaseous state. 50.

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

  Then, the amount of power supplied from the first power supply 53A to the first heating unit 53 is controlled so that the measurement result of the temperature by the first thermometer 54 becomes a set predetermined temperature, and the compound supply pipe 52 and the compound storage 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 moved 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 toward the first space F of the reaction chamber 2 and is supplied into the first space F.

  In addition, the manufacturing apparatus 1 has a boiling point of a compound (in this example, anhydrous magnesium chloride) whose plasma is to be treated in the reaction chamber 2 is not less than the boiling point (when the pressure in the reaction chamber 2 is about 10 Pa, the boiling point is about 650 ° C.). A temperature control means 60 for maintaining the temperature is provided.

  Specifically, the temperature control means 60 is provided in the first space F of the reaction chamber 2 and heats the inside of the reaction chamber 2, and a second heating section 61 for supplying electric power to the second heating section 61. A power supply 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 supply amount of power supplied from the second power supply 61A to the second heating unit 61 such that the measurement result of the temperature by the second thermometer 62 becomes a set predetermined temperature. Then, the temperature in the first space F of the reaction chamber 2 is maintained at a predetermined temperature.

In the present embodiment, the temperature control means 60 keeps the temperature in the reaction chamber 2 at about 700 ° C., which is the temperature at which anhydrous magnesium chloride, which is a compound to be treated with plasma, 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., the boiling point is maintained at about 700 ° C. which is higher than the boiling point in the present embodiment. 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 be used, and the set temperature set in the temperature control means 60 is changed according to the difference of the compound.

  On the other hand, a reflector 70 that reflects the radiant heat is provided outside the second heating unit 61 in order to prevent the casing 10 from being heated by the radiant heat from the second heating unit 61. A cooling pipe 71 for water cooling is provided on the outer surface.

  As described above, in a case where the manufacturing apparatus 1 includes the heat insulating unit such as the reflector 70 that prevents heat conduction so that an extra place is not heated by the second heating unit 61, the housing 10 does not reach a high temperature. Not only can the deterioration of the packing and the like used in various parts of the body 10 be suppressed, but also the heat retention efficiency is increased, so that the 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 partitioning portion 11 at a position near the center on the upper side. As will be described later, a gas containing hydrogen plasma and magnesium is emitted from the insertion tube 72 to the second space S.

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

  As mentioned above, the microwave surface wave plasma has a feature that the temperature of ions and molecules in the plasma is much lower than that of thermal plasma (almost at room temperature). By locating the surface 81 near the insertion tube 72, even if the surface 81 is located within the range where the plasma in the reaction chamber 2 exists (within the range in which the emission color of the hydrogen plasma can be visually observed), it is simple as described below. With such a configuration, the surface temperature (temperature of the surface 81) of the attaching means 80 can be set to a surface temperature at which magnesium hydride can be deposited as a solid.

  The adhering means 80 has a medium supply port IN for supplying a temperature control medium (for example, outside air as a refrigerant) and a medium discharge port OUT for discharging the temperature control medium, and the temperature control medium is in the second space of the reaction chamber 2. It has a closed container structure that does not leak to S.

  The attaching means 80 has a surface 81 on the side opposite to the insertion tube 72 on which the magnesium product containing magnesium hydride is attached, and a high-density hydrogen plasma from which the emission state emitted from the insertion tube 72 can be visually confirmed. By being arranged at the position where it is in direct contact, it is arranged within the range where the generated hydrogen plasma exists.

The manufacturing apparatus 1 includes, for example, a not-shown medium supply unit (for example, a fan or a compressor) for supplying outside air serving as a temperature control medium from the medium supply port IN into the attachment unit 80. The surface temperature of the surface 81 on which the magnesium product containing magnesium hydride 80 is adhered is controlled to a temperature within a predetermined temperature range suitable for depositing the product containing magnesium hydride.
When using outside air as the temperature control medium as described above, a pipe may be connected so that the medium outlet OUT is open to the atmosphere.

  On the other hand, in the case of using, for example, alternative CFCs as the temperature control medium, a circuit for compressing the alternative CFCs discharged from the medium discharge port OUT with a compressor and introducing the compressed alternative CFCs again from the medium supply port IN. What is necessary is just to make it like a cooling system (what is called a refrigerator etc.).

  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 performing circulation for returning the temperature control medium discharged from the medium discharge port OUT 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 still more preferably 100 ° C. or lower, since the amount of precipitation is significantly reduced when the temperature exceeds 200 ° C.

  In an experiment, in the case of a product containing magnesium hydride precipitated at a state where the surface temperature exceeds 200 ° C., water drops are dropped on the product, and it has been confirmed that the firing phenomenon accompanying the separation of hydrogen is extremely weak.

  On the other hand, in the case of a product containing magnesium hydride precipitated at a surface temperature of 100 ° C. or less, it has been confirmed that dripping a drop of water shows an intense firing phenomenon accompanying the separation of hydrogen. Is hydrogen with a hydrogen detector tube.

  If the surface temperature exceeds 100 ° C., magnesium hydride may be decomposed into hydrogen and metallic magnesium, so that the ratio of magnesium hydride in the product containing magnesium hydride may decrease. Therefore, the predetermined temperature at which magnesium hydride is deposited is most preferably 100 ° C. or lower.

  Also, in the experiments, the amount of magnesium hydride-containing product deposited per unit time was larger at about 70 ° C. than at the surface temperature of about 80 ° C., and the deposited quantity per unit time was further increased at about 50 ° C. From the viewpoint of the amount of precipitation, the surface temperature is preferably controlled to a temperature range of 80 ° C. or less, 70 ° C. or less, and more preferably 50 ° C. or less.

  Further, the manufacturing apparatus 1 is provided with an atmosphere opening pipe 90 provided with a leak valve 91 on the way, and one end (not shown) of the atmosphere opening pipe 90 is opened to the atmosphere outside the building where the manufacturing apparatus 1 is installed. ing.

  The open-to-atmosphere tube 90 is provided to open the reaction chamber 2 to the atmosphere as an emergency measure when the pressure in the reaction chamber 2 becomes abnormal. The atmosphere is prevented from entering the reaction chamber 2.

Next, the manufacturing method of the present embodiment will be specifically described.
First, as a preparatory step, the pressure reducing 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). The procedure for performing is performed.

  Then, the compound is irradiated with a plasma of hydrogen, which is a reactive gas containing substantially no oxygen atoms, in the reaction chamber 2 at a temperature at which the anhydrous magnesium chloride, which is a compound, maintains a gaseous state. When the temperature in the reaction chamber 2 is out of the predetermined temperature range, the plasma is turned on, and then the reaction chamber of the anhydrous magnesium chloride as a compound is produced. The procedure for starting the feed to 2 and producing a product different from the compound is performed.

  More 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 a temperature at which anhydrous magnesium chloride as a compound can be kept in a gaseous state. .

  For this reason, basically, the inner wall surface of the reaction chamber 2 becomes higher than the deposition temperature of metal magnesium of about 400 ° C., so that the metal magnesium hardly adheres to the inner wall surface of the reaction chamber 2.

  However, when a part having a temperature lower than about 400 ° C. is formed on a part of the inner wall surface of the reaction chamber 2 or when the temperature in the reaction chamber 2 is reduced in order to end the procedure for producing a product containing magnesium hydride. In some cases, metallic magnesium precipitates (adheres) on the inner wall surface of the reaction chamber 2.

  If the adhesion of metallic magnesium has occurred on the inner wall surface of the reaction chamber 2 in the previous manufacturing process, the metal magnesium adheres 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 metallic magnesium is 400 ° C. or higher, which is the boiling point, the metallic magnesium may be in a gaseous state and the reaction chamber 2 may be filled with a high concentration of metallic magnesium.

  Here, since metallic magnesium has a property of reflecting microwaves (generally, a single metal often reflects microwaves), the reaction chamber 2 is filled with high-concentration metallic magnesium. Even if the supply of microwaves into the reaction chamber 2 is started in the state of being turned on, the microwaves are reflected, sufficient microwaves cannot enter the reaction chamber 2 through the window W, and plasma does not light.

On the other hand, when the adhesion of metallic magnesium occurs on the inner wall surface of the reaction chamber 2, it is considered that the adhesion of anhydrous magnesium chloride also occurs. Since the gas 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 decreases, sufficient microwaves can enter the reaction chamber 2 from the window W, and plasma can be turned on.

  That is, the temperature in the reaction chamber 2 is set for a metal material (metal magnesium in this example) consisting only of metal atoms of a compound (in this example, anhydrous magnesium chloride) containing metal atoms (magnesium in this example). A predetermined temperature range of not less than the boiling point at the same pressure as the pressure of the reaction chamber 2 (about 10 Pa in this example) (about 400 ° C. or more in this example) and less than the boiling point of the compound (less than about 650 ° C. in this example). Avoiding the temperature, that is, when the temperature is out of the predetermined temperature range, the plasma lighting can be started stably by starting the plasma lighting.

  Therefore, when the pressure in the reaction chamber 2 reaches a predetermined pressure (for example, about 10 Pa), the supply of the reactive gas to be turned into plasma is started into the reaction chamber 2, and the microwave is controlled before the temperature control unit 60 is driven. Even when the microwave supply by the generation unit 20 is started or the temperature control unit 60 is driven, the temperature is out of the predetermined temperature range (in this example, about 400 ° C. or more and less than about 650 ° C.). When the temperature is outside the temperature range, the microwave generation means 20 starts supplying microwaves.

  For example, for this purpose, an interlock that can drive the temperature control unit 60 only after the microwave supply unit 20 starts supplying microwaves to the manufacturing apparatus 1 is provided, or the manufacturing apparatus 1 is provided with a predetermined interlock. A temperature setting mechanism for setting a 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 a predetermined temperature range set, the microwave of the microwave generating means 20 is set. By providing an interlock that cannot start supplying microwaves, it is ensured that the microwave generation means 20 can start supplying microwaves when the temperature inside the reaction chamber 2 is outside a predetermined temperature range, When the temperature in the reaction chamber 2 is out of the predetermined temperature range, the plasma lighting can be started.

  After the start of plasma lighting is confirmed, and when the temperature in the reaction chamber 2 reaches a temperature at which the gaseous state of anhydrous magnesium chloride as a compound can be maintained, the supply of the compound by the compound supply means 50 is performed. In the reaction chamber 2 in which the compound is started and the compound is kept in a gaseous state, the compound is irradiated with plasma of a reactive gas substantially containing no oxygen atom to generate a product different from the compound. Then, a procedure is performed in which the product produced by the procedure is adhered to the surface 81 of the attaching means 80 whose surface temperature is controlled to a temperature within a predetermined temperature range suitable for the precipitation of the product.

  As described above, in the manufacturing apparatus 1 of the present embodiment, the temperature of the reaction chamber 2 is set to be equal to or higher than the boiling point of the metal material having only the metal atoms at the same pressure as the pressure in the reaction chamber 2. When the temperature inside the reaction chamber 2 is out of the predetermined temperature range, the microwave generating means 20 operates so that the plasma lighting can be started when the temperature is out of the predetermined temperature range that is lower than the boiling point of the compound. Since the supply of the microwave can be started, it is possible to avoid that the plasma is not lit well.

  Further, even in the manufacturing method, a 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 in the procedure for generating a product different from the compound. When the temperature is out of a predetermined temperature range that is equal to or higher than the boiling point and lower than the boiling point of the compound containing the metal atom, the plasma is started to be turned on.

As described above, the present invention has been described based on the specific embodiments. However, 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 described. However, the compound for obtaining a product containing magnesium hydride by treating with plasma may be anhydrous magnesium halide.

  In addition to obtaining a product containing magnesium hydride, a compound containing a metal atom having a boiling point higher than that of a metal material consisting of only metal atoms is treated with plasma to obtain a product different from the compound. In such a case, it is considered that the same occurs.

  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 different product from the compound has been described. It is not something to be done.

  As described above, the present invention is not limited to the specific embodiments, but includes appropriately modified or improved ones included in the technical scope of the present invention. Is apparent from the description of the claims.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 Reaction chamber 10 Case 11 Partition part 11A Opening 20 Microwave generation 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 unit 52 Compound supply pipe 53 First heating unit 53A First power supply 54 First thermometer 60 Temperature control means 61 Second heating unit 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 Leak Valve F First space IN Medium supply port MFC1 First flow controller MFC2 Second flow controller OUT Medium discharge port S Second space W Window

Claims (5)

A production method for treating a compound containing a metal atom having a boiling point higher than the boiling point of a metal material consisting only of metal atoms with plasma to obtain a product different from the compound,
A step of irradiating the compound with a plasma of a reactive gas containing substantially no oxygen atoms to generate a product different from the compound in a reaction chamber at a temperature that maintains a gaseous state,
When the temperature in the reaction chamber is out of a predetermined temperature range, lighting of the plasma is started,
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 at the same pressure as the pressure in the reaction chamber set at the time of the procedure and lower than the boiling point of the compound. Manufacturing method.   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 an attachment unit which is arranged in a range where the plasma exists in the reaction chamber and whose surface temperature is controlled to a temperature within a predetermined temperature range suitable for deposition of the product. The production method according to claim 1 or 2, wherein A manufacturing apparatus for obtaining a product different from the compound by treating a compound containing the metal atom having a boiling point higher than the boiling point of a metal material consisting of only metal atoms with plasma,
The manufacturing apparatus includes:
Decompression means for depressurizing the reaction chamber,
Temperature control means for keeping the reaction chamber at or above the boiling point of the compound,
Gas supply means for supplying a reactive gas substantially free of oxygen atoms to be converted into plasma into the reaction chamber,
Microwave generation means for generating a microwave supplied into the reaction chamber to generate the plasma,
A window made of a dielectric material for entering the microwave, provided in the reaction chamber,
When the temperature in the reaction chamber is out of a predetermined temperature range, the microwave generating means is configured to start the plasma lighting when the temperature in the reaction chamber is out of the predetermined temperature range. Supply can be started,
The manufacturing apparatus according to claim 1, wherein the predetermined temperature range 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 at the same pressure as the set pressure in the reaction chamber. The manufacturing apparatus includes:
Compound supply means for supplying the compound in a gaseous state into the reaction chamber,
An attachment unit which is disposed within a range where the plasma exists in the reaction chamber and whose surface temperature is controlled to a temperature within a predetermined temperature range suitable for deposition of the product. 5. The manufacturing apparatus according to 4.