Method and apparatus for producing inorganic powder using chemical vapor synthesis.

Abstract

To provide: a manufacturing method of inorganic powder using a chemical vapor phase synthetic method, which is capable of increasing a manufacturing yield by suppressing a side reaction, and of increasing stability of continuous steps by preventing a reaction vessel from being closed; and a manufacturing device thereof.SOLUTION: A manufacturing method of inorganic powder using a chemical vapor phase synthetic method according to one embodiment of the present invention comprises the steps of: feeding a precursor; feeding a side reaction prevention gas for preventing a side reaction of the precursor to the precursor; feeding a reaction gas to the precursor; and forming inorganic powder by chemically reacting the precursor with the reaction gas.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technical concept of the present invention relates to a method for producing inorganic powder, and more particularly, to a method and apparatus for producing inorganic powder using a chemical vapor synthesis method that can suppress side reactions to increase the production yield and further increase the stability of the continuous process by preventing reactor blockage. [Background technology]

[0002] Inorganic powders, such as metal powders or ceramic powders, are utilized in various technological fields. For example, nickel powder, a type of metal powder, is used in the electrode layers of multilayer ceramic capacitors (MLCCs). Multilayer ceramic capacitors are chip-shaped capacitors that temporarily charge electricity or remove noise in electronic circuits. They store current and stably supply only the necessary amount of electricity to ensure that electronic devices function correctly. The most important technology in such multilayer ceramic capacitors is to layer nickel electrode layers as thinly and as many times as possible.

[0003] One method for producing metal powders or ceramic powders is chemical vapor phase synthesis. Chemical vapor phase synthesis produces a solid-phase substance through a chemical reaction between a vaporized precursor and a reaction gas. When chlorides are used as the precursor, they become saturated with water due to their high hygroscopicity. This water reacts with the chlorides to form oxides at undesirable locations, potentially clogging the reactor. This can reduce the yield of inorganic powder production and the stability of the continuous process. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application No. 2013-548154 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The technical problem that the present invention aims to solve is to provide a method and apparatus for producing inorganic powder using a chemical vapor phase synthesis method that can suppress side reactions to increase the production yield and further increase the stability of the continuous process by preventing reactor blockage.

[0006] However, these challenges are illustrative, and the technical concept of the present invention is not limited to them. [Means for solving the problem]

[0007] According to one aspect of the present invention, a method for producing inorganic powder using chemical vapor phase synthesis and an apparatus for producing it are provided.

[0008] According to one embodiment of the present invention, the method for producing inorganic powder using the chemical vapor phase synthesis method may include the steps of: supplying a precursor; supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor; supplying a reaction gas to the precursor; and forming inorganic powder by a chemical reaction between the precursor and the reaction gas.

[0009] According to one embodiment of the present invention, the side reaction prevention gas can suppress the formation of metal oxides due to the chemical reaction between the precursor and water or oxygen.

[0010] According to one embodiment of the present invention, the water may be provided in a state in which it is chemically or physically adsorbed onto the precursor, or in a state in which a hydrate has been formed.

[0011] According to one embodiment of the present invention, the side reaction prevention gas may be the same as a part of the products formed by the chemical reaction between the precursor and water or oxygen.

[0012] According to one embodiment of the present invention, the side reaction prevention gas can suppress the formation of some of the products formed by the chemical reaction between the precursor and water or oxygen, thereby suppressing the chemical reaction between the precursor and water or oxygen.

[0013] According to one embodiment of the present invention, the side reaction prevention gas can suppress or delay the formation of the inorganic powder by the chemical reaction between the precursor and the reaction gas.

[0014] According to one embodiment of the present invention, the side reaction prevention gas may be the same as a part of the products formed by the chemical reaction between the precursor and the reaction gas.

[0015] According to one embodiment of the present invention, the side reaction prevention gas can suppress the formation of some of the products formed by the chemical reaction between the precursor and the reaction gas, thereby suppressing the chemical reaction between the precursor and the reaction gas.

[0016] According to one embodiment of the present invention, the precursor may contain one or more of the elements constituting the side reaction prevention gas.

[0017] According to one embodiment of the present invention, the nonmetallic element of the precursor and the nonmetallic element of the side reaction prevention gas may be the same substance.

[0018] According to one embodiment of the present invention, the precursor may include one or more of the following: metal chloride, metal acetate, metal bromide, metal carbonate, metal carbonyl, metal fluoride, metal hydroxide, metal iodide, metal nitrate, metal oxide, metal phosphate, metal silicate, metal sulfate, and metal sulfide.

[0019] According to one embodiment of the present invention, the metal constituting the precursor may include one or more of the following: nickel, copper, silver, iron, aluminum, silicon, boron, cobalt, platinum, gold, tin, magnesium, tungsten, niobium, molybdenum, zinc, yttrium, zirconium, ruthenium, iridium, tantalum, and titanium.

[0020] According to one embodiment of the present invention, the side reaction prevention gas may include one or more of the following: hydrogen chloride gas (HCl), acetic acid gas (C2H4O2), hydrogen bromide gas (BrH), carbon dioxide gas (H2CO3), hydrogen fluoride gas (HF), water vapor (H2O), hydrogen iodide gas (HI), nitric acid gas (HNO3), phosphoric acid gas (H3PO4), silicon hydride gas (SiH4), sulfuric acid gas (H2SO4), chlorine gas (Cl2), and hydrogen sulfide gas (H2S).

[0021] According to one embodiment of the present invention, the reaction gas may include a reducing gas comprising one or more of hydrogen gas, carbon monoxide gas, magnesium vapor gas, sodium vapor gas, and calcium vapor gas; an oxidizing gas comprising one or more of oxygen gas, water vapor gas, and ozone gas; a nitriding gas comprising one or more of ammonia gas and nitrogen gas; or a carbonizing gas comprising one or more of methane gas and acetylene gas.

[0022] According to one embodiment of the present invention, the inorganic powder may contain metal powder.

[0023] According to one embodiment of the present invention, the inorganic powder may include ceramic powder.

[0024] According to one embodiment of the present invention, the method for producing inorganic powder using the chemical vapor phase synthesis method may include the steps of: supplying a precursor; supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor; supplying a reaction gas to the precursor; and a step of the precursor and the reaction gas chemically reacting to form a metal powder.

[0025] According to one embodiment of the present invention, the precursor is nickel chloride, the side reaction prevention gas is hydrogen chloride gas, the reaction gas is hydrogen gas, the metal powder is nickel powder, and the hydrogen chloride gas can suppress the formation of nickel oxide formed by the chemical reaction between the precursor and water.

[0026] According to an embodiment of the present invention, the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the water can satisfy the range of the following formula.

[0027] P / P HCl 2 ≦10 6

[0028] According to an embodiment of the present invention, the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas can satisfy the following range.

[0029] 10 -18 ≦P H2 / P HCl 2

[0030] According to an embodiment of the present invention, the precursor is copper chloride, the side reaction prevention gas is hydrogen chloride gas, the reaction gas is hydrogen gas, the metal powder is copper powder, and the hydrogen chloride gas can suppress the formation of copper oxide formed by the chemical reaction of the precursor and water.

[0031] According to an embodiment of the present invention, the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the water can satisfy the range of the following formula.

[0032] P H2O / P HCl 2 ≦10 15

[0033] According to an embodiment of the present invention, the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas can satisfy the following range.

[0034] 10 -30 ≦P H2 / P HCl 2

[0035] According to one embodiment of the present invention, the method for producing inorganic powder using the chemical vapor phase synthesis method may include the steps of: supplying a precursor; supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor; supplying a reaction gas to the precursor; and forming ceramic powder by a chemical reaction between the precursor and the reaction gas.

[0036] According to one embodiment of the present invention, the apparatus for producing inorganic powder may include: a reaction chamber that provides a reaction space in which a precursor and a reaction gas react to form inorganic powder; a precursor supply unit that supplies the precursor to the reaction chamber; a side reaction prevention gas supply unit that supplies a side reaction prevention gas to the precursor to prevent side reactions of the precursor; and a reaction gas supply unit that supplies the reaction gas to the precursor.

[0037] According to one embodiment of the present invention, the invention may further include a heating unit that provides heat to cause the precursor and the reaction gas to chemically react to form the inorganic powder.

[0038] According to one embodiment of the present invention, the side reaction prevention gas supply unit may include a first side reaction prevention gas supply unit that is located inside the precursor supply unit and provides the side reaction prevention gas inside the precursor supply unit.

[0039] According to one embodiment of the present invention, the side reaction prevention gas supply unit may include a second side reaction prevention gas supply unit that is located outside the precursor supply unit and provides the side reaction prevention gas to the outside of the precursor supply unit.

[0040] According to one embodiment of the present invention, the side reaction prevention gas supply unit may be configured to be integrated with the precursor supply unit.

[0041] According to one embodiment of the present invention, the side reaction prevention gas and the precursor may be supplied simultaneously or at different times.

[0042] According to one embodiment of the present invention, the invention may further include an internal precursor storage unit installed inside the precursor supply unit for storing the precursor.

[0043] According to one embodiment of the present invention, the precursor supply unit may include a nozzle unit that supplies the precursor in a vaporized state.

[0044] According to one embodiment of the present invention, the reaction chamber may consist of a vaporization region in which the precursor vaporizes, a reaction region in which the precursor and a reaction gas react to form an inorganic powder, and a collection region for collecting the inorganic powder.

[0045] According to one embodiment of the present invention, the reaction chamber may consist of one or more of the following: a vertical reaction chamber with a hollow shape extending in the vertical direction, a horizontal reaction chamber with a hollow shape extending in the horizontal direction, and an oblique reaction chamber with a hollow shape extending in the oblique direction. [Effects of the Invention]

[0046] According to the technical concept of the present invention, a method for producing inorganic powder using chemical vapor phase synthesis and a production apparatus can suppress the formation of metal oxides by chemical reaction between the precursor and water prior to the reaction of the precursor with the reaction gas by supplying the aforementioned side reaction prevention gas. This can suppress the formation of inorganic powder composed of metal oxides formed at undesirable locations by the chemical reaction between the precursor and water, or suppress the formation of inorganic powder composed of metals formed at undesirable locations by the chemical reaction between the precursor and the reaction gas. Therefore, it is possible to prevent the reactor from becoming clogged due to the formation of metal oxides and inorganic powders formed at undesirable locations, prevent the depletion of the precursor, and ensure a quantitative supply of the precursor. This increases the production yield of inorganic powder and the stability of the continuous process.

[0047] The effects of the present invention described above are illustrative and do not limit the scope of the invention. [Brief explanation of the drawing]

[0048] [Figure 1] This is a schematic diagram illustrating an apparatus for producing inorganic powder using the chemical vapor synthesis method described above, according to one embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating an apparatus for producing inorganic powder using the chemical vapor synthesis method described above, according to one embodiment of the present invention. [Figure 3] This flowchart shows a method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention. [Figure 4] This is a schematic diagram showing blockage of the precursor supply section due to a side reaction in a method for producing inorganic powder using the chemical vapor phase synthesis method according to one embodiment of the present invention. [Figure 5] This graph shows the change in Gibbs free energy with temperature for the chemical reaction of nickel chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 6] This graph shows the calculation results of the phase content relative to nickel chloride by adding a side reaction prevention gas in a method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 7] This graph shows in detail the change in Gibbs free energy with temperature for the chemical reaction of nickel chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 8] This graph shows in detail the change in Gibbs free energy with temperature for the chemical reaction of nickel chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 9] This graph shows in detail the change in Gibbs free energy with temperature for the chemical reaction of nickel chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 10]This graph shows the change in Gibbs free energy with temperature for the chemical reaction of copper chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 11] This graph shows the change in Gibbs free energy with temperature for the chemical reaction of aluminum chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention. [Figure 12] This is a photograph showing the state of the reaction chamber depending on whether or not side reactions were prevented in the method for producing inorganic powder using the chemical vapor phase synthesis method according to one embodiment of the present invention. [Figure 13] This is a photograph of inorganic powder formed by the method for producing inorganic powder using the chemical vapor synthesis method described in one embodiment of the present invention. [Modes for carrying out the invention]

[0049] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are provided to further fully illustrate the technical idea of ​​the invention to those ordinary skill in the art, and the embodiments described below can be modified into various other forms; the scope of the technical idea of ​​the invention is not limited to these embodiments. Rather, these embodiments are provided to further enrich and complete this disclosure and to fully communicate the technical idea of ​​the invention to those skilled in the art. Throughout this specification, the same reference numerals mean the same elements. Furthermore, various elements and areas in the drawings are shown schematically. Therefore, the technical idea of ​​the invention is not limited by the relative sizes or spacing shown in the accompanying drawings.

[0050] In this specification, "precursor" means a precursor for inorganic powder production, and refers to a substance in the form of a compound containing a metal element that is used to produce inorganic powder. The precursor can form a metal powder or a ceramic powder as the final synthesized inorganic powder.

[0051] In this specification, the term “side reaction” means a reaction in which an oxide such as nickel oxide or aluminum oxide is formed, along with a reaction in which an inorganic powder such as nickel, nickel oxide, or aluminum oxide is formed to adhere to the inside and outside of the precursor supply section.

[0052] The aforementioned side reactions, for example, when synthesizing a metal powder such as nickel powder as the final product, can refer to a reaction in which nickel oxide is formed and adheres to the precursor supply unit before the precursor comes into contact with the reaction gas, and can refer to a reaction in which nickel is formed and adheres to the precursor supply unit after the precursor comes into contact with the reaction gas.

[0053] Furthermore, the aforementioned side reaction can refer to, for example, a reaction in which, when synthesizing a ceramic powder such as aluminum oxide powder as the final product, the precursor forms aluminum oxide before and after contact with the reaction gas and adheres to the precursor supply section.

[0054] In other words, if such substances adhere to the precursor supply section, it can cause blockage of the precursor supply section; therefore, it is necessary to suppress the formation of such substances.

[0055] In this specification, the term "side reaction prevention gas" refers to a gas that can prevent the aforementioned side reactions, and means a gas that, for example, hydrogen chloride, causes a reverse reaction and thereby suppresses or removes the formation of oxides or inorganic powders.

[0056] The present invention provides a method for producing inorganic powder using a chemical vapor phase synthesis method, wherein by supplying a side reaction prevention gas to the precursor, the formation of oxides formed by the chemical reaction between the precursor and water chemically or physically adsorbed to the precursor, or in a hydrated state, can be suppressed or delayed. Furthermore, the formation of some inorganic powder that is formed at undesirable locations by the chemical reaction between the precursor and the reaction gas can be suppressed or delayed.

[0057] Figures 1 and 2 are schematic diagrams illustrating an inorganic powder manufacturing apparatus for producing inorganic powder using the chemical vapor synthesis method described above, according to one embodiment of the present invention.

[0058] Referring to Figures 1 and 2, the inorganic powder manufacturing apparatus 100, 100a may include a reaction chamber 110, a precursor supply unit 120, a reaction gas supply unit 130, a first side reaction prevention gas supply unit 140, a second side reaction prevention gas supply unit 150, and a heating unit 160.

[0059] The inorganic powder manufacturing apparatus 100a shown in Figure 2 may further include an internal precursor storage unit 123 installed inside the precursor supply unit 120 for storing the precursor.

[0060] The reaction chamber 110 can provide a reaction space in which a precursor and a reaction gas react to form an inorganic powder. Although the drawing shows a vertical reaction chamber with a hollow shape extending vertically, this is illustrative and the technical concept of the present invention is not limited thereto. For example, the reaction chamber 110 may be a horizontal reaction chamber with a hollow shape extending horizontally, or an oblique reaction chamber with a hollow shape extending diagonally.

[0061] The reaction chamber 110 may consist of a vaporization region 112 in which the precursor vaporizes, a reaction region 114 in which the precursor and a reaction gas react to form an inorganic powder, and a collection region 116 for collecting the formed inorganic powder.

[0062] If the reaction chamber 110 is a vertical reaction chamber, the vaporization region 112, the reaction region 114, and the collection region 116 may be arranged in order from the top, where the gas begins to flow, downwards.

[0063] If the reaction chamber 110 is a horizontal or inclined reaction chamber, the vaporization region 112, reaction region 114, and collection region 116 may be arranged in order from one side where the gas begins to flow toward the other side which is the target of the gas flow.

[0064] The precursor supply unit 120 may be located on one side of the reaction chamber 110, for example, in the vaporization region 112, or for example, on the upper side. The precursor supply unit 120 can supply the vaporized precursor, formed by vaporizing the precursor by heating, to the reaction region 114 of the reaction chamber 110, and for this purpose may include the vaporized precursor or various flow channels through which the vaporized precursor can flow.

[0065] The precursor supply unit 120 may be configured to include a precursor injection unit 122, a precursor containment unit 124, and a nozzle unit 126.

[0066] The precursor injection section 122 may be located above the precursor supply section 120 and may be configured as a separate tube or as a part of the precursor supply section 120. The precursor injection section 122 can supply the solid-state precursor, which is the raw material, to the precursor containment section 124 together with the carrier gas using the flow of the carrier gas. The carrier gas may include an inert gas such as argon or nitrogen.

[0067] As another example, as shown in Figure 2, an internal precursor storage unit 123 is installed inside the precursor supply unit 120. The internal precursor storage unit 123 stores the precursor in a solid state in advance. The precursor is vaporized by heating, and after the vaporized precursor is discharged from the internal precursor storage unit 123, the precursor is transported inside the reaction chamber 110 by a carrier gas introduced into the precursor supply unit 120.

[0068] Furthermore, in order to ensure a uniform flow rate of the precursor supplied to the reaction region 114, if the precursor is partially removed from the precursor supply unit 120, a quenching gas for cooling may be supplied in addition. The quenching gas may be supplied via the precursor supply unit 120 or via a separate flow path that is additionally installed.

[0069] The precursor containment section 124 can contain the precursor that has vaporized externally or internally. The precursor containment section 124 may be positioned corresponding to the vaporization region 112.

[0070] The nozzle section 126 is positioned below the precursor containment section 124 and can function as a channel for introducing the vaporized precursor into the reaction region 114. In other words, the precursor supply section 120 may include a nozzle section 126 that supplies the precursor in a vaporized state. The shape and path of the nozzle section 126 are not particularly limited, as long as it has a configuration for supplying the precursor to the reaction region 114.

[0071] The reaction gas supply unit 130 may be positioned in the reaction chamber 110 to supply the vaporized precursor or a reaction gas that reacts with the vaporized precursor into the reaction chamber 110.

[0072] The reaction gas may be, for example, a reducing gas, an oxidizing gas, a nitriding gas, or a carbonizing gas. The reaction gas may include, for example, a reducing gas containing one or more of hydrogen gas, carbon monoxide gas, magnesium vapor gas, sodium vapor gas, and calcium vapor gas; an oxidizing gas containing one or more of oxygen gas, water vapor gas, and ozone gas; a nitriding gas containing one or more of ammonia gas and nitrogen gas; or a carbonizing gas containing one or more of methane gas and acetylene gas.

[0073] In the drawings, the reaction gas supply unit 130 is shown to be located above the reaction chamber 110, but this is illustrative, and the shape and path are not particularly limited as long as it has a configuration for directly supplying the reaction gas to the reaction region 114.

[0074] The side reaction prevention gas supply unit may be configured to include one or more of the first side reaction prevention gas supply unit 140 and the second side reaction prevention gas supply unit 150.

[0075] The first side reaction prevention gas supply unit 140 can supply a side reaction prevention gas. The first side reaction prevention gas supply unit 140 is located inside the precursor supply unit 120 and can supply the side reaction prevention gas to the inside of the precursor supply unit 120.

[0076] The first side reaction prevention gas supply unit 140 supplies the side reaction prevention gas to the inside of the precursor supply unit 120, thereby chemically reacting with the metal oxide formed by the chemical reaction between the precursor and water to remove the metal oxide or to suppress the formation of the metal oxide. This prevents the precursor containment unit 124 or nozzle unit 126 from becoming blocked due to the formation of the metal oxide inside the precursor containment unit 124 or nozzle unit 126, prevents the exhaustion of the precursor and ensures a quantitative supply of the precursor, thereby increasing the production yield of inorganic powder and the stability of the continuous process.

[0077] The second side reaction prevention gas supply unit 150 can supply a side reaction prevention gas. The second side reaction prevention gas supply unit 150 is located outside the precursor supply unit 120 and can supply the side reaction prevention gas to the outside of the precursor supply unit 120.

[0078] The second side reaction prevention gas supply unit 150 supplies the side reaction prevention gas to the outside of the precursor supply unit 120, thereby chemically reacting with the metal oxide formed by the chemical reaction between the precursor and water to remove the metal oxide or suppress its formation. Furthermore, by delaying the chemical reaction between the precursor and the reaction gas, the side reaction prevention gas can remove a portion of the inorganic powder or suppress its formation both inside and outside the precursor supply unit 120, for example, inside and outside the precursor containment unit 124 or nozzle unit 126. This prevents the precursor supply unit 120 from becoming blocked due to the formation of metal oxide and inorganic powder inside and outside the precursor supply unit 120, prevents the exhaustion of the precursor, and ensures a quantitative supply of the precursor, thereby increasing the production yield of inorganic powder and the stability of the continuous process.

[0079] The first side reaction prevention gas supply unit 140 is optional and may be omitted. For example, the first side reaction prevention gas supply unit 140 may be integrated with the precursor supply unit 120. The side reaction prevention gas and the precursor may be supplied simultaneously via the precursor injection unit 122 of the precursor supply unit 120. Furthermore, the technical concept of the present invention also includes cases where the side reaction prevention gas and the precursor are supplied at different times via the precursor injection unit 122 of the precursor supply unit 120.

[0080] Furthermore, even when the first side reaction prevention gas supply unit 140 and the precursor supply unit 120 have separate configurations, the side reaction prevention gas can be supplied simultaneously with the precursor. Also, the case where the side reaction prevention gas and the precursor are supplied at different times is included in the technical concept of the present invention.

[0081] Furthermore, the second side reaction prevention gas supply unit 150 is optional and may be omitted. Alternatively, only one of the first side reaction prevention gas supply unit 140 and the second side reaction prevention gas supply unit 150 may be selected and installed.

[0082] The aforementioned side reaction prevention gas may include, for example, hydrogen chloride (HCl) gas. However, this is illustrative, and the side reaction prevention gas may include all types of gases capable of preventing side reactions, and these are within the technical scope of the present invention. The side reactions and the side reaction prevention gas will be described in detail below.

[0083] The heating unit 160 can provide heat to allow the precursor and the reaction gas to chemically react and form an inorganic powder. The heating unit 160 may be positioned on the outer circumferential surface of the reaction chamber 110 to heat the reaction chamber 110. The heating unit 160 may consist of, for example, an electrically heated resistance heater.

[0084] The heating section 160 is divided into multiple heaters, and the temperature of each heater can be controlled independently. For example, three heaters may be arranged downwards, such as a first heater 162, a second heater 164, and a third heater 166. Each of the first heater 162, the second heater 164, and the third heater 166 can be controlled to a different temperature from each other, thereby realizing various temperature distributions depending on the position of the reaction chamber 110.

[0085] Figure 3 is a flowchart showing a method for producing inorganic powder using a chemical vapor synthesis method according to one embodiment of the present invention.

[0086] Referring to Figure 3, the method for producing the inorganic powder (S100) includes the steps of supplying a precursor (S110), supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor (S120), supplying a reaction gas to the precursor (S130), and forming an inorganic powder through a chemical reaction between the precursor and the reaction gas (S140).

[0087] The aforementioned side reaction prevention gas can suppress the formation of metal oxides formed by the chemical reaction between the precursor and water or oxygen.

[0088] The side reaction prevention gas may be identical to some of the products formed by the chemical reaction between the precursor and water, and according to Le Chatelier's principle, the chemical reaction between the precursor and water can be suppressed.

[0089] The water or oxygen can chemically react with the precursor to form a metal oxide.

[0090] The water may be supplied chemically or physically adsorbed onto the precursor, or in the form of a hydrate. Alternatively, the water may be supplied in a form remaining in the reaction chamber, supplied by leakage, or supplied as part of the carrier gas and reaction gas. Generally, the water is most abundant as water of crystallization (chemical bonding). Furthermore, because reactors cannot be 100% perfectly sealed, water and oxygen may enter through minute leaking.

[0091] Furthermore, the side reaction prevention gas can suppress or delay the formation of some inorganic powders formed by the chemical reaction between the precursor and the reaction gas. The side reaction prevention gas may be identical to some of the products formed by the chemical reaction between the precursor and the reaction gas, and the chemical reaction between the precursor and the reaction gas can be suppressed according to Le Chatelier's principle.

[0092] The precursor may contain one or more of the elements constituting the side reaction prevention gas. For example, the nonmetallic element of the precursor and the nonmetallic element of the side reaction prevention gas may be the same substance. For example, both the nonmetallic element of the precursor and the nonmetallic element of the side reaction prevention gas may be chlorine (Cl). For example, the precursor may be nickel chloride (NiCl2) and the side reaction prevention gas may be hydrogen chloride (HCl), and both the precursor and the side reaction prevention gas may be chlorides. Alternatively, for example, the precursor may be copper chloride (CuCl) and the side reaction prevention gas may be hydrogen chloride (HCl), and both the precursor and the side reaction prevention gas may be chlorides. Alternatively, for example, the precursor may be aluminum chloride (AlCl3) and the side reaction prevention gas may be hydrogen chloride (HCl), and both the precursor and the side reaction prevention gas may be chlorides.

[0093] The aforementioned precursor may include, but is not limited to, one or more of the following: metal chloride, metal acetate, metal bromide, metal carbonate, metal carbonyl, metal fluoride, metal hydroxide, metal iodide, metal nitrate, metal oxide, metal phosphate, metal silicate, metal sulfate, and metal sulfide.

[0094] The metals constituting the precursor may include, for example, one or more of the following: nickel, copper, silver, iron, aluminum, silicon, boron, cobalt, platinum, gold, tin, magnesium, tungsten, niobium, molybdenum, zinc, yttrium, zirconium, ruthenium, iridium, tantalum, and titanium. However, this is merely an example, and the technical concept of the present invention is not limited thereto.

[0095] For example, the precursor may be a chloride. The precursor may include, for example, one or more of the following: nickel chloride, copper chloride, silver chloride, iron chloride, aluminum chloride, cobalt chloride, platinum chloride, gold chloride, tin chloride, magnesium chloride, tungsten chloride, niobium chloride, molybdenum chloride, zinc chloride, yttrium chloride, zirconium chloride, ruthenium chloride, iridium chloride, tantalum chloride, and titanium chloride. However, this is illustrative and the technical concept of the present invention is not limited thereto.

[0096] The aforementioned side reaction prevention gas may include, for example, one or more of the following: hydrogen chloride gas (HCl), acetic acid gas (C2H4O2), hydrogen bromide gas (BrH), carbon dioxide gas (H2CO3), hydrogen fluoride gas (HF), water vapor (H2O), hydrogen iodide gas (HI), nitric acid gas (HNO3), phosphoric acid gas (H3PO4), silicon hydride gas (SiH4), hydrogen gas (H2), sulfuric acid gas (H2SO4), chlorine gas (Cl2), and hydrogen sulfide gas (H2S). However, this is merely an example, and the technical concept of the present invention is not limited thereto.

[0097] The reaction gas may be a reducing gas, an oxidizing gas, a nitriding gas, or a carbonizing gas. The reaction gas may include a reducing gas comprising one or more of hydrogen gas, carbon monoxide gas, magnesium vapor gas, sodium vapor gas, and calcium vapor gas; an oxidizing gas comprising one or more of oxygen gas, water vapor gas, and ozone gas; a nitriding gas comprising one or more of ammonia gas and nitrogen gas; or a carbonizing gas comprising one or more of methane gas and acetylene gas. However, these are examples only, and the technical concept of the present invention is not limited thereto.

[0098] The following describes an exemplary method for producing inorganic powder using the inorganic powder production apparatus 100.

[0099] A precursor that forms the desired inorganic powder is injected into the precursor supply unit 120 via the precursor injection unit 122, along with a carrier gas. If the precursor is pre-stored in the internal precursor storage unit 123 within the precursor supply unit 120, only the carrier gas may be injected into the precursor injection unit 122 to allow for gas flow.

[0100] In the precursor supply unit 120 located in the vaporization region 112 of the reaction chamber 110, the precursor is vaporized to form a vaporized precursor. Such vaporization may be performed by the first heater 162 of the heating unit 160. The vaporized precursor is supplied to the reaction region 114 of the reaction chamber 110 via the nozzle unit 126. In addition, the reaction gas and carrier gas may be preheated in the vaporization region 112.

[0101] In the reaction region 114 of the reaction chamber 110, the vaporized precursor and the reaction gas supplied via the reaction gas supply unit 130 react with each other to form an inorganic powder.

[0102] In the collection area 116 of the reaction chamber 110, the formed inorganic powder is collected. The collected inorganic powder can then undergo a series of processes such as classification and powder washing. The collection apparatus and collection method can be carried out in various ways and are within the technical scope of the present invention.

[0103] The temperature of each region in the reaction chamber 110 can be selected in various ways depending on the precursor being introduced. The vaporization region 112 may have a temperature range in which the precursor can be vaporized, for example, in the range of 20°C to 1400°C. The reaction region 114 may have a temperature range in which the precursor and the reaction gas react, for example, in the range of 200°C to 1400°C. The collection region 116 may have a temperature range in which the formed inorganic powder precipitates into a solid phase, for example, in the range of 20°C to 1000°C.

[0104] The inorganic powder produced by this method may include, for example, nickel, copper, silver, iron, aluminum, silicon, boron, cobalt, platinum, gold, tin, magnesium, tungsten, niobium, molybdenum, zinc, yttrium, zirconium, ruthenium, iridium, tantalum, titanium, and alloys containing these. However, this is merely an example, and the technical concept of the present invention is not limited thereto.

[0105] Alternatively, the inorganic powder may be, for example, one oxide, nitride, or carbide of any one of the following: nickel, copper, silver, iron, aluminum, silicon, boron, cobalt, platinum, gold, tin, magnesium, tungsten, niobium, molybdenum, zinc, yttrium, zirconium, ruthenium, iridium, tantalum, or titanium. However, this is merely an example, and the technical concept of the present invention is not limited thereto.

[0106] The inorganic powder may include metal powder, ceramic powder, or both. For example, the inorganic powder may include one or more of nickel powder, copper powder, nickel-copper alloy powder, aluminum oxide powder, iron-aluminum oxide powder, and aluminum nitride powder. However, this is illustrative and the technical idea of ​​the present invention is not limited thereto.

[0107] A method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention may include the steps of: supplying a precursor; supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor; supplying a reaction gas to the precursor; and a step of forming a metal powder by a chemical reaction between the precursor and the reaction gas.

[0108] The precursor is nickel chloride, the side reaction prevention gas is hydrogen chloride gas, the reaction gas is hydrogen gas, the metal powder is nickel powder, and the hydrogen chloride gas can suppress the formation of metal oxides formed by the chemical reaction between the precursor and water.

[0109] For example, if the precursor is nickel chloride and the synthesized inorganic powder is nickel powder, the method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention may include the steps of supplying nickel chloride, supplying hydrogen chloride gas to the nickel chloride to prevent side reactions of the nickel chloride, supplying a reaction gas to the nickel chloride, and forming nickel powder by a chemical reaction between the nickel chloride and the reaction gas.

[0110] For example, after solid-phase nickel chloride is vaporized, the vaporized nickel chloride is supplied to the reaction chamber 110 by a carrier gas, and the nickel chloride is subjected to a reduction reaction using a reducing gas such as hydrogen to nucleate and grow nickel particles, thereby forming the nickel powder.

[0111] The hydrogen chloride gas can suppress or delay the formation of nickel oxide through the chemical reaction between the nickel chloride and water. Furthermore, the hydrogen chloride gas can suppress or delay the formation of nickel powder through the chemical reaction between the nickel chloride and the reaction gas.

[0112] Thus, in order to prevent the side reaction of nickel chloride, the relationship between the partial pressures of hydrogen chloride gas and water, and the relationship between the partial pressures of hydrogen chloride gas and hydrogen gas must be taken into consideration.

[0113] In order to suppress or delay the formation of nickel oxide by the chemical reaction between the nickel chloride and the water, the relationship between the partial pressure of hydrogen chloride gas and the partial pressure of water can satisfy the following range.

[0114] Nickel chloride in the gas phase: P H2O / P HCl 2 ≤10 3

[0115] Solid-phase nickel chloride: P H2O / P HCl 2 ≤106

[0116] The aforementioned P H2O / P HCl 2 The upper limit for nickel chloride in the gas phase is 10 3 If it exceeds 10, or if it is a solid-phase nickel chloride, the upper limit is 10. 6 If it exceeds that value, that is, if the partial pressure of water is even higher, the effect of preventing the aforementioned side reaction may be slight.

[0117] The aforementioned P H2O / P HCl 2 The lower limit is not limited, but if the amount of hydrogen chloride gas is excessive, it may reduce the formation reaction of inorganic powder in the reaction region, so it is preferable to control it. For example, the P H2O / P HCl 2 The lower limit is 10 for gaseous nickel chloride. -15 It may also be 10 in the case of solid-phase nickel chloride. -5 That's fine.

[0118] In order to suppress or delay the formation of nickel powder in the nozzle section due to the chemical reaction between nickel chloride and hydrogen, the relationship between the partial pressure of hydrogen chloride gas and the partial pressure of hydrogen gas can satisfy the following range.

[0119] 10 -18 ≤P H2 / P HCl 2 ≤10 3

[0120] On the other hand, in the reaction region, the nickel powder should be formed by a chemical reaction between the nickel chloride and the hydrogen, and the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas at this time can satisfy the range of the following equation.

[0121] 10 -8 ≤P H2 / P HCl 2

[0122] Here, P H2 / P HCl 2 There is no upper limit, but for example, 10 1000000 That's fine.

[0123] For example, if the precursor is copper chloride and the inorganic powder to be synthesized is copper powder, the method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention may include the steps of supplying copper chloride, supplying hydrogen chloride gas to the copper chloride to prevent side reactions of the copper chloride, supplying a reaction gas to the copper chloride, and forming copper powder by a chemical reaction between the copper chloride and the reaction gas.

[0124] For example, after solid-phase copper chloride is vaporized, the vaporized copper chloride is supplied to the reaction chamber 110 by a carrier gas, and the copper chloride nucleates and grows copper particles through a reduction reaction using a reducing gas such as hydrogen, thereby forming the copper powder.

[0125] The hydrogen chloride gas can suppress or delay the formation of copper oxides through the chemical reaction between the copper chloride and water. Furthermore, the hydrogen chloride gas can suppress or delay the formation of copper powder through the chemical reaction between the copper chloride and the reaction gas.

[0126] Thus, in order to prevent the side reaction of copper chloride, the relationship between the partial pressures of hydrogen chloride gas and water, and the relationship between the partial pressures of hydrogen chloride gas and hydrogen gas must be taken into consideration.

[0127] In order to suppress or delay the formation of the copper oxide by the chemical reaction between the copper chloride and the water, the relationship between the partial pressure of hydrogen chloride gas and the partial pressure of water can satisfy the following range.

[0128] Copper chloride in the gas phase: P H2O / P HCl 2 ≤101

[0129] Solid-phase copper chloride: P H2O / P HCl 2 ≤10 15

[0130] The aforementioned P H2O / P HCl 2 The upper limit for copper chloride in the gas phase is 10 1 If it exceeds 10, or if it is the upper limit for solid-phase copper chloride, then 10 15 If it exceeds that value, that is, if the partial pressure of water is even higher, the effect of preventing the aforementioned side reaction may be slight.

[0131] The aforementioned P H2O / P HCl 2 The lower limit is not limited, but if the amount of hydrogen chloride gas is excessive, it may reduce the formation reaction of inorganic powder in the reaction region, so it is preferable to control it. For example, the P H2O / P HCl 2 The lower limit is 10 for gaseous copper chloride. -25 It may also be 10 in the case of solid-phase copper chloride. -1 That's fine.

[0132] In order to suppress or delay the formation of the copper powder in the nozzle section due to the chemical reaction between the copper chloride and the hydrogen, the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas can satisfy the following range.

[0133] 10 -30 ≤P H2 / P HCl 2 ≤10 1

[0134] On the other hand, in the reaction region, the formation of the copper powder should occur through a chemical reaction between the copper chloride and the hydrogen, and the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas at this time can satisfy the range of the following equation.

[0135] 10 -20 ≤P H2 / P HCl 2

[0136] Here, P H2 / P HCl 2 There is no upper limit, but for example, 10 1000000 That's fine.

[0137] A method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention may include the steps of: supplying a precursor; supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor; supplying a reaction gas to the precursor; and forming ceramic powder by a chemical reaction between the precursor and the reaction gas.

[0138] For example, if the precursor is aluminum chloride and the synthesized inorganic powder is aluminum oxide powder, the method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention may include the steps of supplying aluminum chloride, supplying hydrogen chloride gas to the aluminum chloride to prevent side reactions of the aluminum chloride, supplying a reaction gas to the aluminum chloride, and a step of the aluminum chloride and the reaction gas chemically reacting to form aluminum oxide powder.

[0139] For example, after a solid phase of aluminum chloride is vaporized, the vaporized aluminum chloride is supplied to the reaction chamber 110 by a carrier gas, and the aluminum chloride undergoes an oxidation reaction using an oxidizing gas such as water to nucleate and grow aluminum oxide particles, thereby forming the aluminum oxide powder.

[0140] Furthermore, the hydrogen chloride gas can suppress or delay the formation of aluminum oxide through a chemical reaction between the aluminum chloride and water as the reaction gas.

[0141] Thus, in order to prevent the side reaction of the aluminum chloride, the relationship between the partial pressures of the hydrogen chloride gas and the water must be considered.

[0142] When suppressing or delaying the formation of the aluminum oxide by the chemical reaction of the aluminum chloride and the water, the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the water can satisfy the following range.

[0143] Vapor-phase aluminum chloride: P H2O <w 3 / P HCl 6 ≤ 10 -1

[0144] Solid-phase aluminum chloride: P H2O 3 / P HCl 6 ≤ 10 -5

[0145] The P H2O 3 / P HCl 6 is the upper limit of 10 in the case of vapor-phase aluminum chloride -1 exceeds, or exceeds the upper limit of 10 in the case of solid-phase aluminum chloride -5 That is, when the partial pressure of water is even higher, the effect of preventing the side reaction may be slight.

[0146] The P H2O 3 / P HCl 6 The lower limit of is not limited, but when the hydrogen chloride gas is excessively high, it may reduce the formation reaction of the inorganic powder in the reaction region, so it is preferably controlled. For example, the P H2O 3 / P HCl 6 The lower limit of may be 10 in the case of vapor-phase aluminum chloride -30 and may be 10 in the case of solid-phase aluminum chloride -25 as well.

[0147] On the other hand, in the reaction region, the formation of the aluminum oxide powder should occur through a chemical reaction between the aluminum chloride and the water, and the relationship between the partial pressure of hydrogen chloride gas and the partial pressure of water at this time can satisfy the range of the following equation.

[0148] 10 -25 ≤P H2O 3 / P HCl 6

[0149] Here, P H2O 3 / P HCl 6 There is no upper limit, but for example, 10 1000000 That's fine.

[0150] For example, if the precursor is aluminum chloride and the synthesized inorganic powder is aluminum nitride powder, the method for producing inorganic powder using a chemical vapor phase synthesis method according to one embodiment of the present invention may include the steps of supplying aluminum chloride, supplying hydrogen chloride gas to the aluminum chloride to prevent side reactions of the aluminum chloride, supplying a reaction gas to the aluminum chloride, and forming aluminum nitride powder by a chemical reaction between the aluminum chloride and the reaction gas.

[0151] For example, after solid-phase aluminum chloride is vaporized, the vaporized aluminum chloride is supplied to the reaction chamber 110 by a carrier gas, and the aluminum chloride is subjected to a nitriding reaction using a nitriding gas such as ammonia to nucleate and grow aluminum nitride particles, thereby forming the aluminum nitride powder.

[0152] Figure 4 is a schematic diagram showing the blockage of the precursor supply section due to a side reaction in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention.

[0153] Referring to Figure 4, the above-described chemical reaction may form an oxide 128, such as nickel oxide or aluminum oxide, inside the precursor supply unit 120, and such an oxide 128 may be deposited as a solid phase inside the nozzle unit 126. Such deposition may be performed in the precursor containment unit 124 or the nozzle unit 126 of the precursor supply unit 120. Since such an oxide 128 consumes the chloride of the precursor, the chloride may not be supplied quantitatively to the reaction region 114 (see Figure 1). In addition, the oxide 128 may be deposited as a solid phase outside the precursor supply unit 120. In this way, if the oxide 128 precipitates inside and outside the precursor supply unit 120, the gas pressure may change due to the unwanted consumption of the chloride of the precursor, which may change the conditions of the manufacturing process, and furthermore, the precursor supply unit 120, for example, the nozzle unit 126, may be blocked by the oxide 128 on the inside, outside, or both inside and outside.

[0154] Furthermore, when inorganic powder 129 such as nickel or aluminum oxide is formed on the inside and outside of the precursor supply unit 120 by the chemical reaction, the inorganic powder 129 may solidify on the outside of the precursor supply unit 120, the gas pressure may change due to the unwanted consumption of chlorides in the precursor, and the precursor supply unit 120, for example, the nozzle unit 126, may be blocked by the inorganic powder 129.

[0155] On the other hand, in the method for producing inorganic powder using chemical vapor phase synthesis according to the technical concept of the present invention, by further providing a side reaction prevention gas such as hydrogen chloride gas, the formation of oxides and inorganic powder inside and outside the precursor supply unit 120 can be prevented. This ensures a quantitative supply of the precursor to the reaction region, prevents the generation of a pressure difference in the precursor supply unit 120, and prevents blockage of the precursor supply unit 120, for example, the nozzle unit 126.

[0156] The side reaction prevention gas may be supplied into the precursor supply unit 120 via the precursor injection unit 122. Alternatively, the side reaction prevention gas may be supplied via a side reaction prevention gas supply unit. For example, the side reaction prevention gas may be supplied into the precursor supply unit 120 in the reaction chamber 110 via a first side reaction prevention gas supply unit 140, and supplied to the inside of the nozzle unit 126. For example, the side reaction prevention gas may be supplied to the outside of the precursor supply unit 120 in the reaction chamber 110 via a second side reaction prevention gas supply unit 150, and supplied to the outside of the nozzle unit 126.

[0157] The side reaction prevention gas may be injected in a continuous, uniform rate, a continuous, non-uniform rate, a discontinuous, uniform rate, or a discontinuous, non-uniform rate.

[0158] In the following, the roles of side reactions and side reaction prevention gases in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention will be explained based on thermodynamic theory.

[0159] In the following explanation, we will use an example where the precursor is nickel chloride, the reaction gas is hydrogen gas, the inorganic powder is nickel powder, and the side reaction prevention gas is hydrogen chloride.

[0160] Figure 5 is a graph showing the change in Gibbs free energy with temperature for the chemical reaction of nickel chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention.

[0161] Referring to Figure 5, nickel chloride can undergo the reaction shown in the following chemical formula.

[0162] [ka]

[0163] [ka]

[0164] [ka]

[0165] If the precursor is nickel chloride, nickel powder can be formed according to the chemical formula 1.

[0166] According to the Gibbs free energy mentioned above, below approximately 1400°C, the reaction in which nickel chloride reacts with hydrogen gas to form nickel becomes dominant, and for this to occur, hydrogen gas must be provided.

[0167] Therefore, in environments where hydrogen gas is not supplied, such as inside the precursor supply unit 120, the reaction in which nickel chloride reacts with water to form nickel oxide becomes dominant. As shown in chemical formula 2, before the nickel chloride vaporizes, solid-phase NiCl2(s) can react with water (H2O) to form nickel oxide (NiO). As shown in chemical formula 3, after the nickel chloride vaporizes, gas-phase NiCl2(g) can react with water (H2O) to form nickel oxide (NiO).

[0168] The precursor is in a solid phase at room temperature and may contain water that is chemically or physically adsorbed or in the form of a hydrate. In particular, metal chlorides such as nickel chloride are difficult to dry completely, contain even trace amounts of water (H2O), and are highly hygroscopic, making the adsorption of water (H2O) or the formation of a hydrate very easy. The water is difficult to remove by normal drying.

[0169] Furthermore, because water (H2O) is highly reactive with NiCl2(s) and NiCl2(g), it causes a reaction in which nickel chloride reacts with water to form nickel oxide, consuming the nickel chloride raw material and forming unwanted nickel oxide (NiO). In other words, the water can undergo the chemical reaction of chemical formula 2 with solid-phase nickel chloride. Alternatively, the water can undergo the chemical reaction of chemical formula 3 with gas-phase nickel chloride. This can lead to the formation of an oxide, such as nickel oxide (NiO).

[0170] Since the aforementioned nickel oxide can clog the precursor supply section in the manufacturing apparatus or deplete the nickel in the nickel precursor, it is preferable to remove the nickel oxide or suppress the formation of the nickel oxide.

[0171] When nickel oxide is formed in this way, hydrogen chloride (HCl) is also produced as another product. If it is to suppress the formation of the nickel oxide, this can be achieved by supplying hydrogen chloride (HCl) to inhibit the forward reaction or by inducing the reverse reaction.

[0172] Specifically, by supplying additional hydrogen chloride to the precursor supply unit 120, the forward reaction in which nickel chloride reacts with water is suppressed, or the reverse reaction in which nickel oxide reacts with the supplied hydrogen chloride occurs, thereby suppressing the formation of nickel oxide or removing the nickel oxide.

[0173] Furthermore, the nickel formed adjacent to the precursor supply unit 120, either inside or outside, may be deposited onto the precursor supply unit 120, for example, onto the nozzle unit 126, thereby potentially blocking the nozzle unit 126. The reactants, NiCl2(g) and hydrogen (H2), can only produce a uniform reaction if they are mixed after being sufficiently preheated to the high reaction temperature. However, due to the high diffusivity of hydrogen (H2), it may diffuse in the opposite direction to the gas flow (i.e., towards the nozzle unit), causing the reaction to occur in undesirable areas, resulting in nickel adhering to the nozzle unit 126 and potentially blocking it.

[0174] Therefore, by supplying additional hydrogen chloride to the inside and outside of the precursor supply unit 120 via one or more of the first side reaction prevention gas supply unit 140 and the second side reaction prevention gas supply unit 150, it is possible to suppress the forward reaction in which nickel chloride reacts with hydrogen to form nickel, or to induce the reverse reaction. This makes it possible to suppress the formation of nickel in undesirable areas of the precursor supply unit 120, for example, the adjacent outer area of ​​the nozzle unit 126, and to ensure that the formation of nickel occurs at a position somewhat separated from the precursor supply unit 120, for example, from the nozzle unit 126.

[0175] As described above, the formation of nickel oxide or nickel can make it difficult to quantitatively supply the NiCl2 precursor, and pressure can be generated in the reaction chamber, making continuous operation difficult. In this invention, to solve these problems, unwanted reactions are suppressed by increasing the partial pressure of hydrogen chloride (HCl) in a localized area.

[0176] In the case of the above chemical formula 1, P H2 / P HCl 2 Only when the ratio of is small can unwanted reactions be suppressed, and in the case of chemical formulas 2 and 3, P H2O / P HCl 2 Only when the ratio of is small can the unwanted reaction be suppressed. Here, PH2 P is the partial pressure of hydrogen gas, H2O P is the partial pressure of water. HCl This is the partial pressure of hydrogen chloride gas.

[0177] Figure 6 is a graph showing the calculation results of the phase content relative to nickel chloride by adding a side reaction prevention gas in the method for producing inorganic powder using the chemical vapor phase synthesis method according to one embodiment of the present invention.

[0178] Referring to Figure 6, it can be seen that when only NiCl2 and H2O are present, NiO formation begins at approximately 300°C, and all NiCl2 is converted to NiO at approximately 750°C. When HCl is provided as a side reaction prevention gas, the NiO formation initiation temperature increases, and the amount of NiO produced decreases. It can be seen that no NiO is produced when the molar ratio of NiCl2 to HCl exceeds 8. The required content of the side reaction prevention gas can be calculated based on the partial pressures of water and hydrogen chloride gas.

[0179] Figures 7 to 9 are graphs that show in detail the change in Gibbs free energy with temperature for the chemical reaction of nickel chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention.

[0180] Referring to Figure 7, the change in Gibbs free energy with temperature for the chemical reaction between the solid phase NiCl2(s) and H2O(g) of chemical formula 2 is shown. The solid phase NiCl2 is P H2O / P HCl 2 When P is 1, it chemically reacts with water at a temperature of approximately 700°C or higher. Considering the internal temperature of the reaction chamber, it is necessary to maintain an appropriate gas partial pressure to suppress the chemical reaction. For example, at a temperature of 900°C, P H2O / P HCl 2 The chemical reaction can be suppressed by providing hydrogen chloride (HCl) in an amount that can form an atmosphere with a concentration of 0.1 or less.

[0181] Referring to Figure 8, the change in Gibbs free energy with temperature for the chemical reaction between NiCl2 (g) and H2O (g) in the gas phase of chemical formula 3 is shown. The NiCl2 in the gas phase is P H2O / P HCl 2 When P is 1, it reacts with H2O at temperatures below 1400°C. However, at low temperatures below 600°C, the saturated vapor pressure of NiCl2 is low, so the reaction needs to be suppressed above the temperature at which a sufficiently effective amount of NiCl2 gas is formed, and for that purpose, it is necessary to maintain an appropriate gas partial pressure. For example, at 600°C, the saturated vapor pressure of NiCl2 is only about 13 Pa, so P H2O / P HCl 2 By providing hydrogen chloride (HCl) in an amount that can form an atmosphere with a concentration of 0.001 or less, the aforementioned chemical reaction can be almost completely suppressed.

[0182] Referring to Figure 9, the change in Gibbs free energy with temperature for the chemical reaction between NiCl2(g) and H2(g) in the gas phase of chemical formula 1 is shown. For example, the formation of nickel powder in unwanted regions such as the nozzle portion 126 is due to the diffusion of hydrogen (H2). Whether the chemical reaction proceeds forward or reverse in such regions depends on P H2 / P HCl 2 This can be determined by the diffused P. H2 Since it is difficult to accurately predict the value of P, H2 / P HCl 2 It is difficult to calculate this precisely. However, P H2 / P HCl 2 The smaller the value, the more effectively nickel deposition can be suppressed.

[0183] In the following explanation, we will use the case where the precursor is copper chloride, the reaction gas is hydrogen gas, the inorganic powder is copper powder, and the side reaction prevention gas is hydrogen chloride as an example.

[0184] Figure 10 is a graph showing the change in Gibbs free energy with temperature for the chemical reaction of copper chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention.

[0185] Referring to Figure 10, copper chloride can undergo the reaction shown in the following chemical formula.

[0186] [ka]

[0187] [ka]

[0188] [ka]

[0189] If the precursor is copper chloride, copper powder can be formed according to the chemical formula 4.

[0190] According to the Gibbs free energy mentioned above, below approximately 1400°C, the reaction in which copper chloride reacts with hydrogen gas to form copper becomes dominant, and for this to occur, hydrogen gas must be provided.

[0191] Therefore, in environments where hydrogen gas is not supplied, such as inside the precursor supply unit 120, the reaction in which copper chloride reacts with water to form copper oxide becomes dominant. As shown in chemical formula 5, before the copper chloride vaporizes, solid-phase CuCl(s) can react with water (H2O) to form copper oxide (Cu2O). As shown in chemical formula 6, after the copper chloride vaporizes, gas-phase CuCl(g) can react with water (H2O) to form copper oxide (Cu2O).

[0192] Since the aforementioned copper oxide can clog the precursor supply section in the manufacturing apparatus or deplete the copper in the copper precursor, it is preferable to remove the copper oxide or suppress the formation of the copper oxide.

[0193] When copper oxide is formed in this way, hydrogen chloride (HCl) is also produced as another product. If it is to suppress the formation of the copper oxide, this can be achieved by supplying hydrogen chloride (HCl) to inhibit the forward reaction or by inducing the reverse reaction.

[0194] As described above, by supplying additional hydrogen chloride to the precursor supply unit 120, the forward reaction in which copper chloride reacts with water is suppressed, or the reverse reaction in which copper oxide reacts with the supplied hydrogen chloride occurs, thereby suppressing the formation of copper oxide or removing the copper oxide.

[0195] Furthermore, supplying additional hydrogen chloride can suppress the forward reaction in which copper chloride reacts with hydrogen to form copper, or induce the reverse reaction. This makes it possible to suppress the formation of copper in undesirable areas of the precursor supply unit 120, for example, the area adjacent to the nozzle unit 126, and to ensure that the formation of copper occurs at a position somewhat separated from the precursor supply unit 120, for example, from the nozzle unit 126.

[0196] In the case of the aforementioned chemical formula 4, P H2 / P HCl 2 Only when the ratio of is small can unwanted reactions be suppressed, and in the case of chemical formulas 5 and 6, P H2O / P HCl 2 Only when the ratio of is small can the unwanted reaction be suppressed. Here, P H2 P is the partial pressure of hydrogen gas, H2O P is the partial pressure of water. HCl This is the partial pressure of hydrogen chloride gas.

[0197] In the following explanation, we will use an example where the precursor is aluminum chloride, the reaction gas is water, the inorganic powder is aluminum oxide powder, and the side reaction prevention gas is hydrogen chloride.

[0198] Figure 11 is a graph showing the change in Gibbs free energy with temperature for the chemical reaction of aluminum chloride generated in the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention.

[0199] Referring to Figure 11, aluminum chloride can undergo the reaction shown in the following chemical formula.

[0200] [ka]

[0201] [ka]

[0202] If the precursor is aluminum chloride, aluminum oxide powder can be formed by the chemical formula 7.

[0203] According to the Gibbs free energy mentioned above, below approximately 1400°C, the reaction in which aluminum chloride reacts with water to form aluminum oxide becomes dominant, and for this to occur, water must be provided.

[0204] As shown in chemical formula 8 above, before the aluminum chloride vaporizes, the solid phase AlCl3(s) can react with water (H2O) to form aluminum oxide (Al2O3). As shown in chemical formula 7 above, after the aluminum chloride vaporizes, the gas phase AlCl3(g) can react with water (H2O) to form aluminum oxide (Al2O3).

[0205] Although the aluminum oxide is the target inorganic powder, if it forms in an undesirable location, it may clog the precursor supply section in the manufacturing apparatus. Therefore, it is necessary to remove the aluminum oxide or suppress its formation.

[0206] When aluminum oxide is formed in this way, hydrogen chloride (HCl) is also produced as another product. If it is to suppress the formation of the aluminum oxide, this can be achieved by supplying hydrogen chloride (HCl) to inhibit the forward reaction or by inducing the reverse reaction.

[0207] As described above, supplying additional hydrogen chloride to the precursor supply unit 120 can suppress the forward reaction in which aluminum chloride reacts with water to form aluminum oxide, or induce the reverse reaction. This makes it possible to suppress the formation of aluminum oxide in undesirable areas of the precursor supply unit 120, such as the area adjacent to the nozzle unit 126, and to ensure that the formation of aluminum oxide occurs at a position somewhat separated from the precursor supply unit 120, for example, from the nozzle unit 126.

[0208] In the case of chemical formulas 7 and 8, P H2O / P HCl 2 Only when the ratio of is small can the unwanted reaction be suppressed. Here, P H2O P is the partial pressure of water. HCl This is the partial pressure of hydrogen chloride gas.

[0209] Furthermore, similar to the aluminum oxides mentioned above, the technical concept of the present invention can also be applied to aluminum nitrides such as those shown in chemical formulas 9 and 10 below.

[0210] [ka]

[0211] [ka]

[0212] In the above description, the case where the chemical vapor synthesis (CVS) method is used to produce inorganic powder has been described, but this is an example and the technical idea of the present invention is not limited thereto.

[0213] The inorganic powder thus formed is applicable to various fine ceramic fields. For example, the nickel powder produced using the manufacturing method and manufacturing apparatus according to the technical idea of the present invention may be applied to the electrode layer of a multilayer ceramic capacitor (MLCC).

[0214] Experimental example

[0215] Hereinafter, preferred experimental examples are presented to assist in the understanding of the present invention. However, the following experimental examples are merely for assisting in the understanding of the present invention, and the present invention is not limited by the following experimental examples.

[0216] For the production of inorganic powder, the inorganic powder production apparatus of FIG. 1 was used.

[0217] As a precursor, a nickel chloride (NiCl2) solid raw material was used. The moisture content of the nickel chloride measured using a halogen moisture meter (Mettler Toledo, HC103) was 0.21% by weight.

[0218] In the example, hydrogen chloride (HCl) was introduced at 0.6 LPM (liter per minute) as a side reaction prevention gas, and nickel powder was formed in an atmosphere where P H2 / P HCl 2 was 0.0098 in reaction region 114 (see FIG. 1).

[0219] In the comparative example, nickel powder was formed without introducing hydrogen chloride (HCl) as a side reaction prevention gas.

[0220] Figure 12 is a photograph showing the state of the reaction chamber depending on whether or not side reactions were prevented in the method for producing inorganic powder using the chemical vapor phase synthesis method according to one embodiment of the present invention.

[0221] Referring to Figure 12, the state of the precursor injection unit 122 that provides nickel chloride after the formation of nickel powder, and the precursor supply unit 120 that houses the precursor injection unit 122 are shown.

[0222] In the comparative example, when the reaction was carried out without adding hydrogen chloride (HCl), nickel oxide was formed on the inner wall of the precursor injection section 122. Nickel oxide was also formed on the lower inner wall of the precursor supply section 120. In addition, a nickel film was formed with a length of approximately 4 cm from the bottom. The nickel film was analyzed to be formed either by the deposition of nickel elements formed after the chemical reaction on the lower inner or outer side of the precursor supply section 120, or by the impact and heat treatment of fine nickel powder formed in the gas phase after the chemical reaction on the lower inner or outer side of the precursor supply section 120.

[0223] On the other hand, in the example, nickel oxide was not formed on the inner wall of the precursor injection section 122. Also, green nickel oxide was not formed on the lower inner wall of the precursor supply section 120. Furthermore, a nickel film was formed for a length of approximately 2 cm from the bottom, i.e., a shorter length compared to the comparative example. By increasing the amount of hydrogen chloride (HCl) added, P H2 / P HCl 2 Further reduction of this value is analyzed to further suppress the formation of the nickel film.

[0224] Figure 13 is a photograph of inorganic powder formed by the method for producing inorganic powder using the chemical vapor synthesis method according to one embodiment of the present invention.

[0225] Referring to Figure 13, the nickel powders of the comparative example formed without the use of hydrogen chloride (HCl) and the example formed using hydrogen chloride (HCl) were almost identical in properties such as particle size, distribution, and shape.

[0226] It will be obvious to anyone with ordinary skill in the art to which the technical concept of the present invention pertains, that the technical concept of the present invention described above is not limited to the embodiments and accompanying drawings, and that various substitutions, modifications, and changes are possible without departing from the technical concept of the present invention. [Explanation of symbols]

[0227] 100, 100a Inorganic powder manufacturing apparatus 110 Reaction Chamber 112 Vaporization Region 114 Reaction Region 116 Collection area 120 Precursor supply section 122 Precursor injection section 123 Internal precursor storage section 124 Precursor housing section 126 Nozzle section 128 Oxides 129 Inorganic powder 130 Reaction gas supply unit 140 First Side Reaction Prevention Gas Supply Unit 150 Second Side Reaction Prevention Gas Supply Unit 160 Heating section 162 First Heater 164 Second Heater 166 Third Heater

Claims

1. The steps of supplying a precursor and The steps include supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor, The steps include supplying a reaction gas to the precursor, The step includes a step in which the precursor and the reaction gas chemically react to form an inorganic powder, The aforementioned side reaction prevention gas is A method for producing inorganic powder using chemical vapor synthesis, wherein the product is identical to a portion of the products formed by the chemical reaction of the precursor with water or oxygen.

2. The aforementioned side reaction prevention gas is A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, which suppresses the formation of metal oxides by a chemical reaction between the precursor and water or oxygen.

3. The method for producing inorganic powder using the chemical vapor synthesis method according to claim 2, wherein the water is provided in a state where it is chemically or physically adsorbed onto the precursor, or in a state where a hydrate has been formed.

4. A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, wherein the side reaction prevention gas suppresses the formation of some of the products formed by the chemical reaction between the precursor and water or oxygen, thereby suppressing the chemical reaction between the precursor and water or oxygen.

5. The aforementioned side reaction prevention gas is A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, which suppresses or delays the formation of the inorganic powder by a chemical reaction between the precursor and the reaction gas.

6. The aforementioned side reaction prevention gas is A method for producing inorganic powder using the chemical vapor synthesis method described in claim 1, wherein a portion of the products formed by the chemical reaction between the precursor and the reaction gas is the same.

7. A method for producing inorganic powder using a chemical vapor synthesis method according to claim 1, wherein the side reaction prevention gas suppresses the formation of a portion of the products formed by the chemical reaction between the precursor and the reaction gas, thereby suppressing the chemical reaction between the precursor and the reaction gas.

8. The aforementioned precursor is A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, comprising one or more of the elements constituting the aforementioned side reaction prevention gas.

9. A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, wherein the nonmetallic element of the precursor and the nonmetallic element of the side reaction prevention gas are the same substance.

10. The aforementioned precursor is Metal chlorides, metal acetates, metal bromides, metal carbonates, metal carbonyls, metal fluorides, metal hydroxides, metal iodides, metal nitrates, metal oxides, metal phosphates, metal silicates, metal sulfates, and metal sulfides. A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, comprising one or more of the following: sulfide.

11. The metal constituting the precursor is A method for producing inorganic powder using the chemical vapor synthesis method according to claim 10, comprising one or more of the following: nickel, copper, silver, iron, aluminum, silicon, boron, cobalt, platinum, gold, tin, magnesium, tungsten, niobium, molybdenum, zinc, yttrium, zirconium, ruthenium, iridium, tantalum, and titanium.

12. The aforementioned side reaction prevention gas is A method for producing inorganic powder using the chemical vapor synthesis method described in claim 1, comprising one or more of the following: hydrogen chloride gas (HCl), acetic acid gas (C2H4O2), hydrogen bromide gas (BrH), carbon dioxide gas (H2CO3), hydrogen fluoride gas (HF), water vapor (H2O), hydrogen iodide gas (HI), nitric acid gas (HNO3), phosphoric acid gas (H3PO4), silicon hydride gas (SiH4), sulfuric acid gas (H2SO4), chlorine gas (Cl2), and hydrogen sulfide gas (H2S).

13. The reacting gas is It contains a reducing gas which includes one or more of the following: hydrogen gas, carbon monoxide gas, magnesium vapor gas, sodium vapor gas, and calcium vapor gas. It contains an oxidizing gas that includes one or more of the following: oxygen gas, water vapor gas, and ozone gas. It contains a nitride gas containing one or more of either ammonia gas and nitrogen gas, or A method for producing inorganic powder using the chemical vapor synthesis method according to claim 1, comprising a carbonized gas containing one or more of methane gas and acetylene gas.

14. The steps of supplying a precursor and The steps include supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor, The steps include supplying a reaction gas to the precursor, The step includes a step in which the precursor and the reaction gas chemically react to form a metal powder, The aforementioned side reaction prevention gas is A method for producing inorganic powder using chemical vapor synthesis, wherein the product is identical to a portion of the products formed by the chemical reaction of the precursor with water or oxygen.

15. The precursor is nickel chloride, The aforementioned side reaction prevention gas is hydrogen chloride gas. The reaction gas is hydrogen gas. The aforementioned metal powder is nickel powder. The method for producing inorganic powder using the chemical vapor synthesis method according to claim 14, wherein the hydrogen chloride gas suppresses the formation of nickel oxide formed by the chemical reaction between the precursor and water.

16. The relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the water satisfies the range of the following equation: PH2O / PHCl2≦106 A method for producing inorganic powder using a chemical vapor synthesis method according to claim 15, wherein the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas satisfies the following range. 10-18≦PH2 / PHCl2

17. The precursor is copper chloride, The aforementioned side reaction prevention gas is hydrogen chloride gas. The reaction gas is hydrogen gas. The aforementioned metal powder is copper powder. The method for producing inorganic powder using the chemical vapor synthesis method according to claim 14, wherein the hydrogen chloride gas suppresses the formation of copper oxides formed by the chemical reaction between the precursor and water.

18. The relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the water satisfies the range of the following equation: PH2O / PHCl2≦1015 A method for producing inorganic powder using a chemical vapor synthesis method according to claim 17, wherein the relationship between the partial pressure of the hydrogen chloride gas and the partial pressure of the hydrogen gas satisfies the following range. 10-30≦PH2 / PHCl2

19. The steps of supplying a precursor and The steps include supplying a side reaction prevention gas to the precursor to prevent side reactions of the precursor, The steps include supplying a reaction gas to the precursor, The step includes a step in which the precursor and the reaction gas chemically react to form a ceramic powder, The aforementioned side reaction prevention gas is A method for producing inorganic powder using chemical vapor synthesis, wherein the product is identical to a portion of the products formed by the chemical reaction of the precursor with water or oxygen.

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