JP4444362B2 - Combustion synthesis method and combustion synthesis apparatus for silicon alloy - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing a silicon alloy containing silicon as a main component.

Silicon is mainly used as a structural material for industrial use mainly as a silicon nitride (Si3N4) compound (for example, Non-Patent Document 1).
However, there are no examples of utilizing silicon as a silicon alloy as an industrial structural material.
2005 Fine Ceramics Industry Trend Survey, published by Japan Fine Ceramics (November 2005)

  Moreover, since silicon nitride is a compound in which silicon and nitrogen are covalently bonded at a constant ratio of 4: 3, the inclusion of impurities, particularly metal elements such as oxygen and iron, cannot be allowed at all. For this reason, since the raw material cost, the synthesis cost, and the product processing cost become extremely expensive, silicon nitride is not an effective means for utilizing silicon for industrial structural materials.

  The present inventors pay attention to the above problems, and in order to effectively use silicon, in particular, low-cost metal silicon containing metal elements such as oxygen and iron as impurities for industrial structural materials, the low-cost metal As a result of earnest research on the method of synthesizing silicon alloys using silicon as a raw material, silicon that can tolerate metal elements such as oxygen and iron as solid solution elements using the controlled combustion synthesis method developed by the present inventors The present inventors have succeeded in synthesizing alloys and found that silicon, which is a low-cost metal, can be used as an industrial structural material, and has completed the present invention.

  In addition, a new combination using a wet compound method and a sintering method, characterized in that it is composed of a silicon alloy powder whose average particle size is controlled to a specific value or less, water, and a molding binder. With the invention of product processing technology, we succeeded in producing sintered silicon alloy.

That is, the present invention supplies a predetermined amount of nitrogen into a vacuumed apparatus,
Metal silicon, aluminum, alumina and / or silica are supplied into a reaction vessel in the apparatus, ignited and burned,
The pressure in the device is detected by a pressure sensor, and the pressure in the device is controlled by a gas pressure control valve having a nitrogen supply function and a reactive gas discharge function in the device.
The temperature in the reaction vessel is detected by a temperature detection means, and a second cooling mechanism by a water cooling jacket that covers the entire apparatus according to the temperature detected by the temperature detection means, and a second by a cooling plate provided in the apparatus. Controlling the temperature in the reaction vessel by controlling the amount of cooling water supplied to the cooling mechanism,
The above problem has been solved by a method for combustion synthesis of a silicon alloy, characterized in that combustion synthesis is performed while controlling the internal pressure of the apparatus to 1 MPa or less and the reaction container temperature to 2000 ° C. or less .

The present invention also includes at least one ignition mechanism, a pressure sensor for detecting the pressure in the apparatus, a nitrogen supply mechanism for supplying nitrogen from the outside, a nitrogen supply function, and a reactive gas discharge function in the apparatus. A pressure control mechanism using a gas pressure control valve, a means for detecting the temperature in the reaction vessel, a first cooling mechanism using a water cooling jacket covering the entire apparatus, and a second cooling mechanism using a cooling plate provided in the apparatus,
A temperature control mechanism for controlling the temperature in the reaction vessel by controlling the amount of cooling water supplied to the first and / or second cooling mechanism according to the temperature detected by the detection means;
Combustion synthesis is carried out while controlling the internal pressure of the apparatus to 1 MPa or less and the reaction container temperature to 2000 ° C. or less.
A controlled combustion synthesizer is provided.

Furthermore, due to the combination of a wet compound process and millimeter wave sintering method, as a manufacturing method for a sintered silicon alloy, a powder of silicon alloy produced using the SHS method and combustion synthesis apparatus of the present invention as a starting material, A hydrous compound manufacturing process in which 0.1% to 10% by weight of an inorganic binder mainly composed of silicon and aluminum, or no addition of the inorganic binder, and an intermediate product shape or a finished product shape are formed. Millimeter wave in a millimeter wave environment of 15 GHz or more in a nitrogen atmosphere in which a green molded product produced by a molding process and a drying process in which the water content is 1% or less by drying is maintained at normal pressure or above normal pressure. Sintered silicon alloy, which is sintered by heating in a temperature range of 1300 to 1900 ° C. and a heating time of 30 minutes to 3 hours The manufacturing method will be described.

  According to the present invention, silicon, which is the most abundant earth resource that has been buried in a state of being stored in a dead state in the form of silicon oxide, in the form of silicon oxide, sand in a meteorite mine, desert, etc. As a result, it can be effectively used in large quantities.

Hereinafter, the configuration of the present invention will be described in detail. The silicon alloy manufacturing method provided by the present invention includes a predetermined amount of silicon and aluminum powder as a main component, a predetermined amount of silicon and / or aluminum oxide, iron, nickel, chromium, molybdenum, manganese, Nitrogen can be continuously supplied at an arbitrary pressure as required, together with a predetermined amount according to need of at least one of titanium, yttrium, magnesium, calcium, zirconium, vanadium, boron, tungsten and cobalt. This is a combustion synthesis method in which the temperature can be controlled and the pressure and reaction temperature are controlled while being charged into a control-type combustion synthesis apparatus developed by the inventors and the like that is configured to be controlled and cooled in the apparatus after completion of the combustion synthesis reaction. . The low cost metallic silicon, recycled silicon and / or metal Aluminum chloride, can be used as the silicon and / or Aruminimu material.

In the present invention, among metal silicon produced from meteorite or cinnabar by ordinary electric furnace reduction refining, it is not a high-priced high-grade metal silicon with low oxygen content for semiconductor use, but has a high oxygen content, and In addition, low-cost metal silicon containing a metal element such as iron as an impurity element can be used as a raw material.

  Combustion synthesis is a synthesis method that applies the exothermic reaction of the charged raw materials, and is expected as a synthesis means that does not require input energy for synthesis, but at a high temperature of 3000 ° C. or more and several tens of atmospheres during the combustion synthesis reaction Therefore, the equipment must have functions and structures that can handle high-temperature and high-pressure reactions, as well as a combustion synthesis reaction control technology to synthesize synthetic products stably at a constant composition. There is a problem that it has not been made, and although a small-scale trial production at the laboratory level has been performed, industrial practical use has not been performed.

  The inventors have eagerly promoted research on the control of combustion synthesis for many years, and can control the combustion synthesis reaction of silicon in a nitrogen atmosphere to 2000 ° C. or less and 1 MPa or less, and the combustion synthesis product is generated in the apparatus. We have succeeded in developing the world's first controlled combustion synthesizer with a controlled cooling configuration.

Inventors have by Rukoto with controlled combustion synthesis apparatus of the present invention, a low-cost metal silicon as the raw material, the first time succeeded in developing a solid solution of silicon alloy mainly composed of silicon and nitrogen. That is, the above silicon alloy was first created by being synthesized by the controlled combustion synthesis apparatus of the present invention.

The functional and operational features of the controlled combustion synthesizer will be described with reference to FIG. FIG. 1 is a conceptual configuration diagram of a controlled combustion synthesis apparatus 10 of the present invention.
This apparatus 10 includes an evacuation mechanism 17 that discharges air in the apparatus before the start of combustion synthesis, at least one ignition mechanism 12 for one or more remotely operable raw material powders that serve as a combustion synthesis start point, and a combustion A pressure sensor 14 that continuously detects the pressure in the apparatus at the time of synthesis, and an external nitrogen source (not shown) that is driven in conjunction with the output from the pressure sensor 14 and through a tube 15 that forms a nitrogen supply mechanism. And a gas pressure control valve 16 capable of controlling the internal pressure of the apparatus by discharging the reaction gas in the apparatus to the outside.
Further, a water cooling jacket 18 covering the entire apparatus and a cooling plate 22 installed in contact with the bottom of the reaction vessel 20 are arranged, and the opening degree of the flow control valve 24 is automatically controlled by the output from the temperature detecting means 23. The temperature is automatically controlled by controlling the amount of cooling water. The flow control valve of the water cooling jacket 18 is not shown. The flow rate control of the cooling plate 22 and the water cooling jacket 18 based on the temperature detection may be performed by both or only one.
In addition, a heating apparatus may be installed in the apparatus as a filling apparatus for excessive cooling during the reaction (not shown).

First, the air in the apparatus is exhausted by the vacuum exhaust mechanism 17, and the apparatus is evacuated.
Next, nitrogen from an external nitrogen source is supplied into the apparatus through the tube body 15, and a predetermined amount of nitrogen is supplied into the apparatus through the gas pressure control valve 16 that controls the pressure in the apparatus, while the target is supplied. The metal silicon, aluminum, alumina, and / or silica raw material weighed in an amount that yields the silicon alloy to be obtained is ignited by the ignition mechanism 12 provided at least at one location.
A pressure sensor 14 for detecting the pressure in the apparatus 10, a tube 15 for supplying nitrogen from the outside, a pressure control mechanism by a gas pressure control valve 16 having a function of discharging the reaction gas in the apparatus, and the temperature in the reaction vessel a detection unit 23, a first cooling mechanism by a water cooling jacket 18 which covers the entire apparatus, comprising a second cooling mechanism of the cooling plate 22 provided in the apparatus, depending on the temperature detected by the temperature detecting means 23 Controlled combustion synthesis is performed while controlling the pressure in the reaction vessel and the temperature in the reaction vessel to predetermined values by a temperature control mechanism for controlling the temperature in the reaction vessel by controlling the amount of cooling water supplied to the first and second cooling mechanisms. carry out.

Silicon alloy synthesized by the controlled combustion synthesis, silicon containing nitrogen 10-45, aluminum 1-40, and oxygen 1-40 by weight% when silicon is a constant value of 50% by weight 2 is shown in FIG. 2 as a ternary phase diagram of nitrogen, aluminum, and oxygen. It is confirmed from the analysis of the X-ray diffraction method (XRD method) that the wide region 26 of the ternary phase diagram of nitrogen, aluminum, and oxygen is a full-solid solid solution single-phase structure mainly composed of silicon. . Furthermore, at least one of iron, nickel, chromium, molybdenum, manganese, titanium, yttrium, magnesium, calcium, zirconium, vanadium, boron, tungsten, and cobalt is present as an inevitable impurity in less than 0.3% by weight. However, it has been confirmed that the total solid solution region 26 does not change at all. As a result, it was confirmed that the inevitable impurity element was dissolved in a solid solution consisting of silicon, nitrogen, aluminum, and oxygen.

In addition, the same applies to silicon 70,40 and 30 wt%, a complete solid solution single-phase region of tissue has identified as composition region of the silicon alloy produced by the present invention. Furthermore, when at least one of iron, nickel, chromium, molybdenum, manganese, titanium, yttrium, magnesium, calcium, zirconium, vanadium, boron, tungsten and cobalt is added in an amount of 0.3 to 10% by weight. The entire solid solution single phase structure region constituted was also identified.

In FIG. 2, the component regions 28 to 34 outside the component region 26 generate a metal oxide compound or composite oxynitride compound that cannot be dissolved in the silicon alloy, and the silicon alloy and the metal oxide compound or composite oxynitride compound Since it becomes a production | generation area | region of a composite phase, it becomes the object of the silicon alloy produced | generated by this invention .

When expressed in terms of quantitative values, by weight percent, silicon <30, silicon> 70, nitrogen <10, nitrogen> 45, aluminum <1, aluminum> 40, oxygen <1, and oxygen> 40, the compound compound is mixed in the silicon alloy The component region is excluded from the scope of the silicon alloy produced by the present invention .

  Iron, nickel, chromium, molybdenum, manganese, titanium, yttrium, magnesium, calcium, zirconium, vanadium, boron, tungsten, and cobalt are all dissolved in the silicon alloy, and the hardness, rigidity, and heat resistance characteristics of the silicon alloy , Has the effect of improving the corrosion resistance. When the total amount added is less than 0.3% by weight, the effect of addition is dilute. When the total amount is 10 or more, a composite compound is formed. Therefore, the total amount added is 0.3% or more and less than 10% by weight.

Another excellent characteristic obtained by the controlled combustion synthesis of the present invention will be described below. That is, there is a pulverization step as an initial step for making a combustion-synthesized silicon alloy into an intermediate product or a finished product. The time for pulverizing to a predetermined particle size is preferably a short time. The silicon alloy that is combustion-synthesized by controlling the temperature and pressure during combustion synthesis to be low shortens the pulverization time to a predetermined particle size.
More specifically, the conventional combustion synthesis performed at a combustion synthesis temperature of 2000 ° C. or more and a combustion synthesis pressure of 1 MPa or more is performed for the grinding time of a silicon alloy synthesized at a combustion synthesis temperature of 2000 ° C. or less and a combustion synthesis pressure of 1 MPa or less. It was shortened by 50% or more with respect to the silicon alloy synthesized by the above.

  In addition, the optimum sintering temperature of the silicon alloy powder synthesized at a combustion synthesis temperature of 2000 ° C. or less and a combustion synthesis pressure of 1 MPa or less is confirmed to be about 100 ° C. lower than that of a silicon alloy synthesized by conventional combustion synthesis. It was.

Next, a manufacturing process for manufacturing a sintered product of an intermediate product or a finished product from the silicon alloy produced according to the present invention will be described in detail by a manufacturing method by a combination of a wet compound method and a sintering method.

  Table 1 shows detailed steps.

Reducing the micropores remaining in the sintered product as much as possible is a major problem in the production of a sintered body using a silicon alloy according to the present invention, and the best methods that can solve this are the wet compound method and the atmospheric pressure sintering. This is a silicon alloy sintering method in combination with at least one of the sintering method, millimeter wave sintering method, and HIP sintering method. Here, the “micropore” is a fine hole discovered at the microscope level.
It should be noted that this method can be effective even when used as a sintering method for non-conductive powders other than silicon alloys.
This will be described in more detail below.

  The silicon alloy synthesized by the controlled combustion synthesizer is pulverized to a target particle size of 1 micron or less by a wet and / or dry pulverizer. In order to improve the relative density after millimeter wave sintering, it is preferable to grind to an average particle size of 500 nm or less. At least one of oxides mainly composed of yttrium, ytterbium, aluminum and zirconium is used as a sintering aid for the purpose of effectively carrying out sintering during or before or after the pulverization. % Can be mixed with 0.1-10 silicon alloy. When the average particle size is small, the required amount of the sintering aid is small, and the average particle size is 500 nm or less, and a high-density sintered body can be secured after sintering without the addition of the sintering aid. The specific gravity of the sintered body was 3.27 or more.

  To the finely pulverized powder, a binder and water, optionally distilled water or purified water are added, and a compound is produced by a kneader. When the particle size of the powder is 500 nm or less, it is not necessary to add a binder. The binder is preferably inorganic, and an inorganic binder mainly composed of silicon and main constituent elements of a silicon alloy is optimal. For the purpose of improving the dispersibility of the inorganic binder, alkaline water whose pH is controlled can be used. A green molded article composed of an inorganic binder or a compound free of binders has the great advantage that the binder removal treatment that is normally performed as a pre-process at the time of sintering becomes unnecessary.

  By performing the kneading step and / or the molding step in the production of hydrous compound in a reduced pressure environment below normal pressure, the micropores inevitably included in the compound can be reduced to the limit value, so particularly high strength is required. For the production of a silicon alloy sintered body used for the intended use, the forming method by the wet compound method is a recommended essential process.

  Next, the molded body formed by reducing the included micropores as much as possible is dried. Drying is preferably natural drying.

At least one of a heating means using millimeter waves, a normal heating means using resistance heating means, or a HIP heating means in a nitrogen atmosphere in which a green molded article appropriately manufactured by the above process is maintained at normal pressure or above normal pressure. A silicon alloy sintered body is manufactured by heating with a heating means at a predetermined temperature and for a predetermined time.
In addition, sintering is basically performed in a temperature range of 1300 to 1900 ° C. and a heating time of 30 minutes to 3 hours.

  In the heating by the millimeter wave, the heating is started from the center of the green molded product. At that time, since the existing micropores float on the surface layer portion of the molded product, the millimeter wave sintering method is an optimum sintering process for reducing the micropores to the limit value.

In the heating by the millimeter wave, since the heating proceeds from the core of the material to be heated, it is necessary to prevent the dissipation of heat from the material to be heated as much as possible. Therefore, it is necessary to arrange a heat insulating material on the outer periphery of the material to be heated.
In order to eliminate this troublesome workability, a hybrid sintering method in which a millimeter wave heating method and a general-purpose heating method are combined is recommended.

  Table 2 summarizes the chemical components of the silicon alloys synthesized by the combustion synthesis method of the present invention while controlling the temperature during the reaction to 2000 ° C. or less and the pressure to 1 MPa or less, and the constituent phases of each.

Examples of the present invention are shown in the inventive materials 1 to 38. As a result of the XRD measurement method, it was confirmed that all the inventive materials have a single one-phase structure. Examples 1 to 28 are silicon, nitrogen, that is a solid solution composed of four elements Aluminum bromide and oxygen has confirmed from elemental image image by electron ray microanalyzer method (EPMA method) of The examples are representative examples of the basic component composition of the silicon alloy produced by the present invention. Examples 29 to 38 are examples in which an alloy element was added to the basic composition of a silicon alloy, and each alloy element constituted a solid solution in which the base composition had a solid solution.

For the purpose of securing a one-phase structure of the silicon alloy, silicon is produced by the present invention by 30 to 70% by weight, 10 to 45 for nitrogen, 1 to 40 for aluminum, and 1 to 40 for oxygen. Was determined as the basic composition.

Secondary alloying elements added for the purpose of improving the characteristics of silicon alloys with basic compositions include iron, nickel, chromium, molybdenum, manganese, titanium, yttrium, magnesium, calcium, zirconium, vanadium, boron, tungsten, and cobalt. Of these, at least one of them may be added in an amount of 0.3% or more and less than 10% by weight.
When the amount added is less than 0.3, the effect is dilute, and when it is 10 or more, a multilayer structure is obtained.

  Examples of the influence of temperature and pressure during combustion synthesis on the characteristics of the silicon alloy having the chemical component shown in Invention Material 6 will be described below.

  Table 3 shows the relationship between the time ratio required for grinding to a particle size of 500 nm and the combustion synthesis conditions. The lower the temperature and pressure, the better the properties to be crushed, but the longer the combustion synthesis time, 1800 ° C. and 0.8 MPa are preferred.

  Table 4 shows the relationship between the optimum sintering temperature and the combustion synthesis conditions determined from the viewpoints of density after sintering and grain growth. As both the temperature and pressure are lowered, the optimum sintering temperature is lowered, but the combustion synthesis time is lengthened, so 1800 ° C. and 0.8 MPa are preferred.

Table 5 shows changes in main characteristic values in accordance with changes in main components in the component regions of silicon 30 to 70, nitrogen 10 to 45, aluminum 1 to 40, and oxygen 1 to 40 by weight% . Of the characteristic values of silicon alloys of basic elements such as silicon, nitrogen, aluminum, and oxygen, the Young's modulus varies greatly with changes in the amount of silicon. The Young's modulus is an important characteristic value that affects the fatigue strength, which is a design standard for machine parts. Since the optimum Young's modulus can be selected in correlation with the Young's modulus of the counterpart material that is in rolling contact, the silicon alloy according to the present invention is extremely advantageous in terms of mechanical design.
The Young's modulus was considered to be a physical property value unique to the material. However, the fact that the Young's modulus can be arbitrarily changed within a specific range in the silicon alloy according to the present invention is also a discovery that overturns the conventional academic knowledge regarding Young's modulus.

  When boron, which adds grain boundary energy, is added as an alloy element, an improvement in fracture toughness is observed, and when a non-oxidizing metal element is added, corrosion resistance and heat resistance are improved.

Table 6 summarizes the sintering characteristics of the silicon alloy according to the present invention. Due to the good grindability of the silicon alloy according to the present invention, processing into ultrafine powder of 500 nm or less can be carried out at low cost. This feature provides a number of new characteristics that cannot be recognized by the prior art.

  The recommended process is to manufacture the base material from the silicon alloy fine powder through compound manufacturing. It is because productivity higher than the process through a granulation process can be ensured from dry powder. Table 1 shows the main steps of the raw material.

  When the particle size is 500 nm or less, it is not necessary to add a binder during the production of the compound. As a result, the binder removal step can be omitted, so that productivity can be improved and good quality can be ensured. For the purpose of ensuring stable production, an inorganic binder having 0.1 to 10 silicon and aluminum as main components can be added by weight%.

  When the particle size is 500 nm or less, it is not necessary to add a sintering aid, but for the purpose of ensuring stable quality, at least one oxide of yttrium, ytterbium, aluminum and zirconium as a main component is used as a sintering aid. %, 0.1 to 10 can be added and a minimum amount of sintering aid can be added.

  Sintering treatment A: Millimeter-wave heated nitrogen atmosphere atmospheric pressure sintering 1700 ° C. X 1 h, sintering treatment B: Normal heating nitrogen atmosphere atmospheric pressure sintering 1700 ° C. X 3 h, sintering treatment C; CIP + nitrogen atmosphere 200 MPa HIP 1700 ° C. X 1 h Is selected as a sintering process for silicon alloys. In particular, it can be said that it is extremely valuable in terms of industrial technology from the viewpoint of low-cost manufacturing that an advanced sintered body can be formed by atmospheric pressure sintering treatment and sintering treatment B.

  A silicon alloy having a particle size of 500 nm or less can secure a specific gravity of 3.25 or more in any sintering process. In particular, it is noteworthy that the specific gravity obtained by atmospheric pressure sintering B of silicon alloy exceeds the specific gravity reported in HIP sintering C of existing non-oxide ceramic silicon nitride.

  In the sintered material of the silicon alloy having a particle size of 500 nm or less, micropores are not recognized in any of the sintering treatments as a result of wide-area observation at the microscope level. Neither metal phase nor ceramic phase is observed.

  It can be concluded that the reason why good sintering characteristics are obtained in any of the sintering treatments is that the silicon alloy fine powder having a particle size of 500 nm or less is excellent in sintering characteristics.

An object of the present invention is to utilize silicon present in the largest amount in the earth's crust as a general-purpose material for industrial use. Table 7 summarizes the characteristic values of silicon nitride, which is a silicon-based ceramic currently used for industrial applications, and sialon and the silicon alloy obtained by the present invention, and the expected manufacturing price.
Sialon uses a raw material of the same price as silicon nitride and uses an expensive reactive sintering method as a sintering method, and is expensive in comparison with the silicon nitride shape material manufacturing price, but is shown for reference.

The most characteristic difference in characteristic values is in the micropores remaining after sintering. In the silicon alloy obtained by the present invention, the remaining micropores are zero, but in silicon nitride, micropores are unavoidably left. Accordingly, the specific gravity of the material of the present invention is larger than that of silicon nitride.

Taking the production of a bearing ball as an example of the production process of the sintered body, the production price of the bearing ball made of special steel is set to the reference value 1, and each of the silicon alloy , silicon nitride and sialon bearing balls according to the present invention is set. The production price ratio was displayed.

First, the price characteristics of the raw material powder
(1) Metal silicon as a main raw material is a low-priced material, but metal silicon for silicon nitride is a high-grade material and expensive.
(2) The energy input during combustion synthesis is zero.
(3) Since the silicon alloy obtained by the present invention has good pulverization properties, the pulverization cost is low. Current silicon nitride has a high pulverization cost because of its poor pulverizability.
(4) Due to the difference in the manufacturing process, a large price difference occurs between the 500 nm silicon alloy powder and the silicon nitride powder, which are the raw materials for the sintered body.
(5) As a result, the silicon alloy according to the present invention is about 1/10 or less of silicon nitride at the raw material price.

Also in the production of bearing balls as the base material, the price advantage of the silicon alloy according to the present invention is exhibited.
(1) A green ball of bearing balls can be efficiently produced from a compound of fine powder of 500 nm using a high-speed molding apparatus. The high-speed molding apparatus is an improved pill manufacturing apparatus for the silicon alloy according to the present invention , and the number of manufactured per minute is 3000. Dozens of silicon nitride balls are manufactured, and 700 balls are manufactured in bearing steel.
(2) Sintering of green silicon balls of a silicon alloy according to the present invention can be performed at a very low cost compared with the HIP sintering method of silicon nitride because a nitrogen normal pressure sintering method by a normal heating method can be used.
(3) As a result, the manufacturing price of the bearing ball made of silicon alloy according to the present invention manufactured by the processes of (1) and (2) is not more than 5 times the manufacturing price of the bearing ball made of special steel.

Since the specific gravity of the silicon alloy according to the present invention is 40% of the specific gravity of the special steel, the production price is approximately doubled when the specific gravity is converted, and the bearing ball made of the silicon alloy according to the present invention is replaced with the special steel bearing ball. The possibility of mass production and mass demand is extremely high.

Since the silicon alloy produced by the present invention can be manufactured at a production price equivalent to that of special steel, it can be used in large quantities as a general-purpose material for industrial use in place of special steel. In the future, annual demand of 2 million tons, equivalent to 10% of the annual production of 20 million tons of special steel, is expected.

The conceptual block diagram of the control-type combustion synthesis apparatus of this invention. FIG. 3 is a ternary phase diagram of nitrogen, aluminum, and oxygen showing a silicon alloy generation region in the case of 50 wt% silicon.

10: Controlled combustion synthesizer 12: Ignition mechanism 14: Pressure sensor 15: Tube (nitrogen supply mechanism)
16: Gas pressure control valve (pressure control mechanism)
18: Water cooling jacket (first cooling means)
20: Reaction vessel 22: Cooling plate (second cooling means)
23: Temperature detection means (temperature control mechanism)
24: Flow control valve (temperature control mechanism)

Claims (2)

A predetermined amount of nitrogen is supplied into the apparatus in a vacuum state,
Metal silicon, aluminum, alumina and / or silica are supplied into a reaction vessel in the apparatus, ignited and burned,
The pressure in the device is detected by a pressure sensor, and the pressure in the device is controlled by a gas pressure control valve having a nitrogen supply function and a reactive gas discharge function in the device.
The temperature in the reaction vessel is detected by a temperature detection means, and a second cooling mechanism by a water cooling jacket that covers the entire apparatus according to the temperature detected by the temperature detection means, and a second by a cooling plate provided in the apparatus. Controlling the temperature in the reaction vessel by controlling the amount of cooling water supplied to the cooling mechanism,
Combustion synthesis is carried out while controlling the internal pressure of the apparatus to 1 MPa or less and the reaction container temperature to 2000 ° C. or less.
Combustion synthesis method of silicon alloy. Pressure by a gas pressure control valve comprising at least one ignition mechanism, a pressure sensor for detecting the pressure in the apparatus, a nitrogen supply mechanism for supplying nitrogen from the outside, a nitrogen supply function and a reaction gas discharge function in the apparatus A control mechanism, a means for detecting the temperature in the reaction vessel, a first cooling mechanism by a water cooling jacket covering the entire apparatus, and a second cooling mechanism by a cooling plate provided in the apparatus,
A temperature control mechanism for controlling the temperature in the reaction vessel by controlling the amount of cooling water supplied to the first and / or second cooling mechanism according to the temperature detected by the detection means;
Combustion synthesis is carried out while controlling the internal pressure of the apparatus to 1 MPa or less and the reaction container temperature to 2000 ° C. or less.
Silicon alloy controlled combustion synthesizer.

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