KR20110061331A - Synthesis method for carbide power - Google Patents

Abstract

PURPOSE: A method for synthesizing carbide is provided to reduce cost required for implementing operational processes by synthesizing carbide under general atmosphere containing oxygen. CONSTITUTION: A method for synthesizing carbide includes the following: The mixture of a first material and carbon is introduced into a crucible(S110). A second material is introduced into on the mixture arranged in the crucible(S120). The crucible is heated at a first temperature in order to melt the second material(S130). Carbide is synthesized by heating the crucible at a second temperature in order to react the first material and carbon(S140). The first material includes at least one of silicon, boron, titanium, zirconium, tungsten, chrome, niobium, and hafnium. The second material includes at least one of aluminum, magnesium, and tin.

Description

Synthesis method for carbide power

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for synthesizing carbides, and more particularly to a method for synthesizing carbides under a general atmosphere in which oxygen is present using a melt of a material having a low melting point.

Carbide is a compound formed by combining a carbon atom with a metal or semimetal element. These carbides are used in a variety of ways, for example, calcium carbide (CaC) is used as a major synthetic source for many chemicals, while carbides of silicon, tungsten or other elements can be used for chemicals at various physical hardness, strength and high temperatures. It has chemical resistance and is used in various fields. Carbide is classified into ionic, crevice and covalent (diamond) carbide according to its atomic structure. Metal elements of groups 1, 11, 2 and 3 of the periodic table form ionic carbides. Pure samples of ionic carbides are transparent solids that react with acids or water to break down into hydroxides of hydrocarbons and metals. In addition, most metal carbides are composed of metal elements of Groups 4 to 10, which are hard and electrically conductive.

Conventionally, a sol-gel method or a gas phase synthesis method is used to manufacture carbides. However, this method has many outputs and has many economical factors.

In addition, there has been an attempt to synthesize various materials having various compositions by using a mechanical chemical method of synthesizing carbides by injecting mechanical energy to induce chemical reactions. However, in the mechanochemical method, the longer the reaction time, the higher the content of impurities, and the production conditions of the reactants vary depending on various process variables. In addition, there is a problem that oxides are formed simultaneously with carbides unless the atmosphere before reaction is precisely controlled. Therefore, carbides were synthesized by reacting the raw material and carbon in an oxygen-free atmosphere, that is, a reducing atmosphere. However, in order to create a reducing atmosphere, a process of making a vacuum state and adding nitrogen, argon, hydrogen gas, etc. is required, which causes troublesome processes and increases production costs.

The present invention provides a carbide synthesis method capable of synthesizing carbides by reacting carbon with raw materials even under an atmosphere in which oxygen is present.

The present invention provides a method for synthesizing carbides that can block oxygen ingress into the atmosphere by metal fusion in the crucible during carbide synthesis.

The present invention is a mixture of carbon and the first material for the synthesis of carbide in the crucible of the graphite material, the second material having a low melting point is added to the mixture, the second material is dissolved at the first temperature after the second temperature In the present invention, there is provided a method for synthesizing a carbide by reacting carbon with a first material of a mixture.

A method for synthesizing a carbide according to an aspect of the present invention comprises the steps of: introducing a mixture of the first material and carbon into the crucible; Injecting a second material onto the mixture in the crucible; Heating the crucible to a first temperature to melt the second material; And heating the crucible to a second temperature to react carbon with the first material of the mixture to synthesize carbide.

The mixture weighs and mixes the first material and carbon according to the molar ratio of carbide.

The second material includes a material having a lower melting point than the first material, the first material includes at least one of silicon, boron, titanium, zirconium, tungsten, chromium, niobium, and hafnium, and the second material is aluminum At least one of magnesium and tin.

The first temperature is equal to or higher than the melting point of the second material and equal to or smaller than the melting point of the first material and the second temperature is equal to or higher than the melting point of the first material.

The step of injecting the second material is spreading the foil of the second material on the first material and the ingot of the second material on the foil.

The carbide according to another embodiment of the present invention is a mixture of the first material and carbon in the crucible and then the second material is added to the mixture, the second material is melted at the first temperature and then at the second temperature It is synthesized by reacting carbon with the first material of the mixture.

Embodiments of the present invention, the first material for the synthesis of carbide and carbon is mixed and uniformly mixed according to the molar ratio of the carbide to be synthesized in the crucible, the second material having a low melting point on the mixture after the crucible Is heated above the melting point of the second material to dissolve the second material, and the crucible is then heated above the melting point of the first material to react carbon with the first material of the mixture to synthesize carbide.

According to embodiments of the present invention, it is possible to block the introduction of oxygen in the atmosphere into the crucible by the fusion of the second material in the crucible during carbide synthesis. Therefore, carbides can be synthesized even in the presence of oxygen, thereby simplifying the process, thereby reducing the production cost.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention and to those skilled in the art. It is provided for complete information.

1 is a schematic cross-sectional view of a carbide synthesis apparatus used for carbide synthesis according to an embodiment of the present invention.

Referring to FIG. 1, a carbide synthesis apparatus includes a crucible 110 in which carbides of a first material are synthesized and a melt of a second material is produced, a crucible lid 120 covering the crucible 110, and a crucible 110. Surrounding insulation 130 and the quartz tube 140, and the heating means 150 is provided outside the quartz tube 140 for heating the crucible 110. In addition, it may further include a control device (not shown) for operating the heating means 150 independently.

The crucible 110 may be manufactured in the shape of a rectangular parallelepiped or a cylindrical shape with an open top, and a mixture of a first material and carbon is introduced into the crucible 110 to synthesize a carbide of the first material, and a second material is injected. Melts. For this purpose, it is preferable that the crucible 110 uses a material having excellent shape stability even at the melting point of the first material. For this purpose, the crucible 110 may be manufactured using quartz. In addition, the crucible 110 may be coated with graphite, which may facilitate the reaction of the first material and carbon. On the other hand, the crucible 110 may be manufactured in one piece or assembled type, for example, the assembled type may be manufactured by manufacturing a plate-like bottom member and side members, and assembling and screwing them.

The crucible lid 120 may be made of the same material as the crucible 110 or may be manufactured by drilling a large amount of holes in a porous graphite or a thin graphite plate. In addition, at least one inlet (not shown) may be provided between the crucible lid 120 and the crucible 110 to inject the first material and the second material into the crucible 110. However, the first and second materials may be introduced into the crucible 110 by opening the crucible lid 120 without providing the inlet.

The heat insulator 130 and the quartz tube 140 are provided outside the crucible 110 to maintain the temperature of the crucible 110 at a temperature such that the second material can maintain a molten state. Keep it. The heat insulator 130 may use graphite felt manufactured by compressing the graphite fiber to a tubular cylinder having a predetermined thickness. In addition, the heat insulator 130 may be formed of a plurality of layers to surround the crucible 110.

The heating means 150 is provided outside the quartz tube 140. For example, a high frequency induction coil may be used as the heating means 150. The crucible 110 is heated by flowing a high frequency current through the high frequency induction coil, for example, by controlling the amount of the high frequency current to heat the crucible 110 above the melting point of the second material so that the second material melts. By heating the crucible 110 above the melting point of one material, the first material and the graphite of the crucible 110 react to allow carbides to be synthesized.

Hereinafter, a method for synthesizing a carbide according to an embodiment of the present invention using the synthesis apparatus will be described with reference to FIGS. 2 and 3 to 6.

2 is a process flowchart of a carbide synthesis method according to an embodiment of the present invention, Figures 3 to 6 is a cross-sectional view of the crucible shown in accordance with the process of the carbide synthesis method according to an embodiment of the present invention.

2 and 3 to 6, in the carbide synthesis method according to an embodiment of the present invention, injecting a mixture 210 of carbon and a first material for carbide synthesis into the crucible 110 (S110). And injecting a second material 220 having a lower melting point than the first material 210 onto the mixture 210 of the first material and carbon (S120), and heating the crucible 110 to a first temperature. Melting the second material 220 in the crucible 110 to generate a solution 230 of the second material (S130), and heating the crucible 110 to a second temperature to produce a first material of the mixture 210. Reacting with carbon and to synthesize a carbide 240 (S140).

S110: Into the crucible 110, a mixture 210 of carbon and a first material for carbide synthesis is introduced. The mixture 210 is weighed and uniformly mixed with the powder of the first material and the carbon powder according to the molar ratio of carbide to be synthesized, and then charged into the crucible 110. Here, the first material may be, for example, silicon (Si), boron (B), titanium (Ti), zirconium (Zr), tungsten (W), chromium (Cr), niobium (Nb), Hafnium (Hf) or the like can be used. The first material may be a material having a melting point higher than that of the second material that is injected into the crucible 110 and melted.

S120: Then, the second material 220 is added to the mixture 210 in the crucible 110. The second material 220 first covers the mixture 210 by covering the foil 210 in the form of a thin sheet of the second material, and then ingots 220a of the second material on the foil 220a of the second material are properly sized. You can cut and put. The second material 220 uses a material having a lower melting point than the first material. As the second material, for example, a melting point of 700 ° C. or less may be used. For example, aluminum (Al), magnesium (Mg), tin (Sn), or the like may be used. Here, aluminum has a melting point of about 660 ° C, magnesium has a melting point of about 650 ° C, and tin has a melting point of about 230 ° C.

S130: Next, a high frequency current flows through, for example, a high frequency induction coil of the heating means 150, thereby heating the crucible 110 to a first temperature. At this time, the crucible 110 is heated above the melting point of the second material 220 introduced into the crucible 110 to melt the second material 220, that is, the foil 220a and the ingot 220b of the second material. Create a melt 230 of two materials. That is, when the aluminum foil and the ingot are introduced into the crucible 110, the heating is at least 660 ° C, the magnesium foil and the ingot are heated at 650 ° C or more, and the tin foil and the ingot are heated at 230 ° C or more. However, the heating temperature of the crucible 110 is preferably heated to a temperature lower than the melting point of the first material for synthesizing carbide.

S140: Then, the crucible 110 is heated to a second temperature higher than the melting point of the mixture 210. When the crucible 110 is heated to the second temperature, the first material and the carbon of the mixture 210 provided under the melt 230 of the second material react with each other, thereby synthesizing the carbide 240 of the first material. . That is, silicon carbide (SiC), boron carbide (B ₄ C), titanium carbide (TiC), zirconium carbide (ZrC), depending on the first material such as silicon, boron, titanium, zirconium, tungsten, chromium, niobium, hafnium, etc. Materials such as tungsten carbide (WC), chromium carbide (Cr ₂ C ₃ ), niobium carbide (NbC), and hafnium carbide (HfC) are synthesized.

Meanwhile, the carbide synthesis method according to the present invention may use various synthesis apparatuses in addition to the synthesis apparatus. That is, a mixture of the first material and carbon is introduced into the crucible, a second material having a low melting point is added thereto, and the crucible is heated to the first temperature to produce a melt of the second material, followed by heating to the second temperature. The carbide synthesis method of the present invention may be performed using various types of synthesis apparatuses capable of synthesizing carbides by reacting carbon with a first material.

Example

As a first embodiment of the present invention, a case in which silicon carbide is synthesized using silicon as a first material and aluminum as a second material will be described.

First, silicon powder and carbon powder, for example graphite powder, are weighed to the molar ratio of carbides to be synthesized, and then uniformly mixed and introduced into the crucible. Cut into pieces and put on aluminum foil. The aluminum foil and the ingot are then melted by heating to a temperature higher than the melting point of aluminum (about 660 ° C.), for example 700 ° C. At this time, the heating time can be adjusted according to the amount of aluminum ingot put into the crucible. Subsequently, if necessary, the aluminum molten surface may be flattened. For this purpose, the crucible may be removed from the heating apparatus and shaken to flow the aluminum melt. Next, the temperature of the crucible is heated to a melting point of silicon (about 1410 ° C.) or more, for example, 1500-1700 ° C., and maintained for a certain time. At this time, the heating time can be adjusted according to the dosage of the silicon powder and graphite powder. Therefore, oxygen that can be introduced from the outside is blocked by the aluminum melt, and silicon carbide (SiC) of the mixed powder is reacted at the lower portion of the aluminum melt to synthesize silicon carbide (SiC).

Next, a case in which titanium carbide is synthesized using titanium as a first material and aluminum as a second material will be described as a second embodiment of the present invention.

First, titanium powder and graphite powder are weighed according to the molar ratio of carbides to be synthesized, and then mixed uniformly and introduced into a crucible. do. The aluminum foil and the ingot are then melted by heating to a temperature higher than the melting point of aluminum (about 660 ° C.), for example 700 ° C. At this time, the heating time can be adjusted according to the amount of aluminum ingot put into the crucible. Subsequently, the aluminum solution may be flattened as necessary, and for this purpose, the aluminum melt may flow by removing the crucible from the heating apparatus and shaking it. Next, the temperature of the crucible is heated to above the melting point of titanium (about 1668 ° C.), for example, 1700 to 1800 ° C., and maintained for a certain time. At this time, the heating time can be adjusted according to the dosage of the titanium powder and carbon powder. Therefore, oxygen that may be introduced from the outside by the aluminum melt is blocked, and titanium carbide (TiC) of the mixed powder reacts at the lower portion of the aluminum melt to synthesize titanium carbide (TiC).

Although the technical spirit of the present invention has been described in detail according to the above embodiment, it should be noted that the above embodiment is for the purpose of description and not for the purpose of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

1 is a schematic cross-sectional view for explaining an example of a carbide synthesis apparatus used in the present invention.

2 is a flowchart illustrating a method of synthesizing carbide according to an embodiment of the present invention.

3 to 6 are cross-sectional views of the crucible shown in accordance with the process sequence of the carbide synthesis method according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110: crucible 120: crucible lid

130: heat insulating material 140: quartz tube

150 heating means 210 mixture of first material and carbon

220: second material 230: fusion of the second material

240: carbide

Claims (8)

Introducing a mixture of first material and carbon into the crucible; Injecting a second material onto the mixture in the crucible; Heating the crucible to a first temperature to melt the second material; And Heating the crucible to a second temperature to react carbon with the first material of the mixture to synthesize carbide. The method of claim 1, wherein the mixture is mixed with the first material and carbon according to the molar ratio of carbide. The method of claim 1, wherein the second material comprises a material having a lower melting point than the first material. 4. The method of claim 3, wherein the first material comprises at least one of silicon, boron, titanium, zirconium, tungsten, chromium, niobium, and hafnium. 4. The method of claim 3, wherein the second material comprises at least one of aluminum, magnesium, and tin. 4. The method of claim 3, wherein the first temperature is at least the melting point of the second material and less than the melting point of the first material, and the second temperature is at least the melting point of the first material. The method of claim 1, wherein injecting the second material comprises laying a foil of a second material on the first material and injecting an ingot of a second material on the foil. A mixture of a first substance and carbon is introduced into a crucible according to claim 1, and then a second substance is added to the mixture, the second substance is melted at a first temperature, and then the Carbide synthesized by reacting carbon with the first material of the mixture.

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