KR20130111703A - Manufacturing method of high purity aluminium nitride - Google Patents

Abstract

PURPOSE: A method of manufacturing high purity aluminum nitride is provided to synthesize high purity aluminum nitride(ALN) by enabling homogeneous nitriding on the inner surfaces of aluminum source particles by performing a nitriding by coating the aluminum source particles with liquid phenol resin solution. CONSTITUTION: A method of manufacturing high purity aluminum nitride comprises the following steps: forming sol by dispersing aluminum source which includes aluminum (Al) components in organic solvent; forming a phenol resin solution in which phenol resin is dissolved; mixing the sol with the phenol resin solution and coating the aluminum source particles within the phenol resin; heat treating a mixed solution of the sol and the phenol resin solution; synthesizing ALN by nitriding heat treated products while injecting reaction gas including nitrogen components; and removing residual carbon contained in the nitrified outcome through a decarburization treatment. The aluminum source contained in the sol and phenol resin contained in the phenol resin solution is 1:0.42-3 in a weight ratio.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high purity aluminum nitride,

More particularly, the present invention relates to a method of producing aluminum nitride by coating aluminum source particles with a liquid phenolic resin solution and subjecting the aluminum source particles to a nitriding treatment so as to obtain a uniform surface (bulk) (AlN) having high purity can be synthesized because the nitriding treatment can be performed, and the uniformity of the nitriding can be achieved not in a localized manner but in a locally large amount of residual oxygen, The present invention relates to a method for producing a high purity aluminum nitride which can minimize the amount of remaining oxygen in aluminum (AlN), can be decarburized at a low temperature after nitriding treatment, and can be completed within a short time.

Aluminum nitride (AlN) is stable at high temperatures, has low dielectric constant and dielectric loss, is excellent in electrical insulation, and has a thermal conductivity of about 320 W / mK, which is higher than that of metal. In addition, aluminum nitride (AlN) has a thermal expansion coefficient of about 2.64 x 10 < ^-6 > / K and is similar to silicon and can be used as a filler for semiconductor substrate materials and polymer package materials.

Due to such physical properties, aluminum nitride (AlN) can be used as a high thermal conductivity insulating substrate, a high corrosion resistant material and the like. Particularly, it is possible to use a package of a highly integrated semiconductor chip requiring excellent electrical insulation and heat dissipation, high temperature materials such as heat exchangers requiring high thermal conductivity and high corrosion resistance,

Methods for producing commercially available aluminum nitride (AlN) powders include Self-Propagating High Temperature Synthesis Method and Carbon Reduction Method.

The carbon reduction method is a method of producing aluminum nitride (AlN) by reducing alumina (Al ₂ O ₃ ) powder to solid phase carbon (C) in a high temperature nitrogen (N ₂ ) atmosphere. However, the carbon reduction method is disadvantageous in that solid carbon is added as a diluent for the reaction of alumina and nitrogen, the temperature of the high-temperature synthesizer must be maintained at 1800 ° C or higher, and oxygen remains in the aluminum nitride (AlN) powder. It is known that the oxygen present inside the aluminum nitride (AlN) is about 1.0 to 2.0 wt%, and such oxygen is an impurity of the aluminum nitride (AlN) powder, which causes the thermal conductivity to deteriorate.

Korean Patent Application No. 10-1993-0008310 discloses a method for producing aluminum nitride (AlN) using a carbon reduction method. However, since high purity alumina must be used, there is a problem in that the production cost of aluminum nitride is increased. In the case of using a solid carbon material such as carbon black, it is difficult to uniformly mix with alumina. There may be a large amount of residual oxygen locally, and there is a limitation in synthesizing aluminum nitride (AlN) having high purity.

The rotating high temperature synthesis method is a method of synthesizing aluminum nitride (AlN) by using heat generated during a chemical reaction.

Korean Patent Application No. 10-1993-0005742 discloses a method in which a sample is prepared by mixing a carbon powder with a metal aluminum powder with a diluent, tapping the sample lightly to form a plate-like aluminum powder compact having a predetermined thickness, charging it into the reactor, And the nitrogen pressure is maintained at 3 to 10 atm. The sample is then subjected to ignition at high-temperature nitrification reaction using an electric arc to produce aluminum nitride powder. However, there is added a step of pulverizing a sample which is a mixture of the produced aluminum nitride powder and carbon powder by using a ball mill and removing the carbon powder by maintaining the pulverized sample at a temperature of 650-750 ° C in an atmosphere or an oxygen atmosphere There is a disadvantage that it is difficult to obtain high purity aluminum nitride (AlN) since the process is complicated and the possibility of introduction of impurities is high.

Korean Patent Application No. 10-1999-0004068 discloses that a powder in which aluminum (Al) powder is 10 to 90% by weight and aluminum nitride (AlN) as a reaction modifier is mixed in an amount of 10 to 90% by weight is subjected to a nitrogen gas pressure of 1 to 10 kg / Cm < 2 > so as to form a powdered filler layer, and then exothermic reaction is performed using a heating body to produce an aluminum nitride powder for refractory material. However, in this method, since a high temperature of 2,000 DEG C or more occurs during a high-temperature rotation reaction, aluminum nitride particles grow large, so that a pulverizing and classifying step is required after synthesis. In addition, many impurities are mixed in the pulverizing step, which causes the purity to be lowered.

Korean Patent Application No. 10-1993-0008310 Korean Patent Application No. 10-1993-0005742 Korean Patent Application No. 10-1999-0004068

The problem to be solved by the present invention is to coat the aluminum source particles with a liquid phenolic resin solution and subject them to a nitriding treatment so that uniform nitriding treatment can be performed not only on the surface of the aluminum source particles but also on the surface (bulk) It is possible to synthesize aluminum nitride (AlN) having high purity since the nitridation is uniformly performed as a whole, so that the problem of locally remaining large amounts of oxygen can be solved, and the aluminum nitride (AlN) And a decarburization process can be carried out at a low temperature after the nitriding process and the decarburization process can be completed within a short time.

The present invention relates to a method for producing a phenolic resin, comprising the steps of: forming a sol in which an aluminum source containing an aluminum (Al) component is dispersed in an organic solvent; forming a phenolic resin solution in which the phenolic resin is dissolved; A step of mixing the sol and the phenol resin solution so as to be coated with the phenol resin solution; and a heat treatment of the mixed solution of the sol and the phenol resin solution; and a step of nitriding the heat- And a step of decarburization treatment to remove residual carbon contained in the nitrided product. The present invention also provides a method for producing aluminum nitride, comprising the steps of:

The aluminum source may be at least one powder selected from alumina (Al ₂ O ₃ ), aluminum hydroxide (Al (OH) ₃ ) and boehmite (AlOOH).

The aluminum source may be a boehmite (AlOOH) powder having an average particle diameter of 10 to 50 nm.

It is preferable that the sol and the phenol resin solution are mixed so that the aluminum source contained in the sol and the phenol resin contained in the phenol resin solution are in a ratio of 1: 0.42 to 3 by weight.

In order to improve the dispersibility of the aluminum source, it is preferable to add a nitric acid (HNO ₃ ) solution to form the sol having a pH ranging from 1 to 4.

The heat treatment is preferably performed in an oxidizing atmosphere at a temperature of 350 to 500 캜.

The reaction gas that acts as nitrogen source 90 in a nitrogen (N ₂₎ and hydrogen (H ₂₎ volume ratio: 10 to 99.9: it is possible to use a mixed gas mixed in a ratio of 0.1, and hydrogen in the nitriding treatment process (H ₂ ) Serves as a reducing agent to trap residual oxygen contained in the aluminum source to reduce residual oxygen.

The nitriding treatment is preferably performed at a temperature of 1500 to 1700 캜.

The decarburization treatment is preferably carried out in an oxidizing atmosphere at a temperature of 650 to 800 ° C.

It is preferable to flow oxygen (O ₂ ) gas at a flow rate of 0.1 to 20 L / min during the decarburization treatment.

According to the present invention, by nitriding aluminum source particles with a liquid phenolic resin solution, uniform nitriding can be performed not only on the surface of the aluminum source particles but also on the surface (bulk) of the aluminum source particles, (AlN) having a high purity can be synthesized, and the amount of oxygen remaining in the synthesized aluminum nitride (AlN) can be minimized And the decarburization process can be performed at a low temperature after the nitriding process, and the decarburization process can be completed in a short time.

By using a mixed gas of nitrogen (N ₂₎ and hydrogen (H ₂₎ as a reaction gas that acts as nitrogen source, the hydrogen in the nitriding treatment process (H ₂₎ it has a residual oxygen by the trap (trap) the oxygen component and the reducing agent act Can be reduced.

By using boehmite (AlOOH), which is cheap in price with an aluminum source and can be produced with a particle size of 500 nm or less (for example, 10 to 50 nm), not only the surface of the aluminum source particle but also the inside (bulk) ), A uniform nitriding process can be performed, and the synthesized aluminum nitride has a small residual oxygen, which is advantageous in that the decarburization process can be performed at a relatively low temperature.

1 and 2 are scanning electron microscope (SEM) photographs of aluminum nitride (AlN) powders prepared according to Example 1. FIG.
3 and 4 are scanning electron microscope (SEM) photographs of aluminum nitride (AlN) powder prepared according to Example 2. FIG.
5 is a graph showing an X-ray diffraction (XRD) pattern of aluminum nitride (AlN) powder prepared according to Example 2. Fig.
FIG. 6 is a graph showing particle size analysis of aluminum nitride (AlN) powder prepared according to Example 2. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the following embodiments are provided so that those skilled in the art will be able to fully understand the present invention, and that various modifications may be made without departing from the scope of the present invention. It is not.

In the following description, 'nano' refers to a size in nanometers (nm), which means a size ranging from 1 nm to 1000 nm.

Aluminum nitride (AlN) has a theoretical thermal conductivity of about 320 W / mK and is an insulator having excellent thermal conductivity and has a thermal expansion coefficient close to that of silicon (Si). Therefore, aluminum nitride (AlN) is widely used for a substrate of a highly integrated semiconductor device, a heat sink, an electrostatic chuck, and the like.

A method for producing aluminum nitride (AlN) according to a preferred embodiment of the present invention comprises the steps of forming a sol in which an aluminum source containing aluminum (Al) component is dispersed in an organic solvent, and a phenol resin solution Mixing the sol and the phenolic resin solution so that the particles of the aluminum source are coated with the phenolic resin; heat treating the mixed solution of the sol and the phenolic resin solution; (AlN) by nitriding the heat-treated product while injecting a reaction gas containing the nitrogen-containing component, and a step of decarburizing to remove the residual carbon contained in the nitrided product.

The aluminum source may be at least one powder selected from alumina (Al ₂ O ₃ ), aluminum hydroxide (Al (OH) ₃ ) and boehmite (AlOOH).

The aluminum source may be a boehmite (AlOOH) powder having an average particle diameter of 10 to 50 nm.

It is preferable that the sol and the phenol resin solution are mixed so that the aluminum source contained in the sol and the phenol resin contained in the phenol resin solution are in a ratio of 1: 0.42 to 3 by weight.

In order to improve the dispersibility of the aluminum source, it is preferable to add a nitric acid (HNO ₃ ) solution to form the sol having a pH ranging from 1 to 4.

The heat treatment is preferably performed in an oxidizing atmosphere at a temperature of 350 to 500 캜.

The reaction gas that acts as nitrogen source 90 in a nitrogen (N ₂₎ and hydrogen (H ₂₎ volume ratio: 10 to 99.9: it is possible to use a mixed gas mixed in a ratio of 0.1, and hydrogen in the nitriding treatment process (H ₂ ) Serves as a reducing agent to trap residual oxygen contained in the aluminum source to reduce residual oxygen.

The nitriding treatment is preferably performed at a temperature of 1500 to 1700 캜.

The decarburization treatment is preferably carried out in an oxidizing atmosphere at a temperature of 650 to 800 ° C.

It is preferable to flow oxygen (O ₂ ) gas at a flow rate of 0.1 to 20 L / min during the decarburization treatment.

Hereinafter, a method of manufacturing aluminum nitride according to a preferred embodiment of the present invention will be described in more detail.

Thereby forming a sol in which an aluminum source is dispersed in an organic solvent.

The aluminum source serves as a source of aluminum (Al) for aluminum nitride formation. As the aluminum source, at least one powder selected from among alumina (Al ₂ O ₃ ), aluminum hydroxide (Al (OH) ₃ ) and boehmite (AlOOH) containing aluminum (Al) Since alumina is expensive, it is difficult to make the particle size of nano-sized particles of 500 nm or less, and it can not make the particle size small, so that the residual oxygen in the synthesized aluminum nitride may be partially high and the local residual of carbon The decarburization process at a high temperature is required and the decarburization process time may be prolonged. On the other hand, the boehmite (AlOOH) is inexpensive and can be produced with a particle size of 500 nm or less (for example, 10 to 50 nm), so that the surface of the aluminum source particle as well as the surface (bulk) The nitriding process can be performed, and the synthesized aluminum nitride has a small residual oxygen, and the decarburization process can be performed at a relatively low temperature.

The organic solvent may be any of various solvents, but it is preferable to use an alcohol-based or acetone-based organic solvent in consideration of the dispersibility of the aluminum source particles, the viscosity of the sol, and the storage stability of the sol.

In order to improve the dispersibility of the aluminum source, it is preferable to add a nitric acid (HNO ₃ ) solution to form a sol. The nitric acid solution is strongly acidic as an acidic solution. In the case of using hydrochloric acid (HCl), there may be a problem that the chlorine (Cl) component should be removed again in the post-process. When using sulfuric acid (H ₂ SO ₄ ), sodium sulfate (Na ₂ SO ₄ ) or senadayi agent (Na ₂ sO _4; thenardite) and the like can be produced, since the phosphoric acid (H ₃ PO ₄₎ the case of using, the secondary phase undesirable because of the phosphorus (P) component can be produced, the aluminum source and It is preferable to use nitric acid (HNO ₃ ) which does not form a salt upon reaction.

The concentration of the nitric acid solution is preferably about 10 to 80%. When the concentration of the nitric acid solution is less than 10%, a large amount of acidic solution is required for improving the dispersibility, and if the concentration of the nitric acid solution exceeds 80%, the acidity is too high and can be dangerous.

It is preferable that the pH of the sol is in the range of 1 to 4 through the addition of the nitric acid solution.

The sol preferably comprises 3 to 40% by weight of an aluminum source. The solid content (aluminum source) of 3 to 40% by weight based on 100% by weight of the sol is preferable considering the dispersibility of the aluminum source particles, the viscosity of the sol, and the long-term storage of the sol.

The phenolic resin is dissolved in a solvent such as acetone to form a phenolic resin solution. A phenolic resin is a material containing carbon (C) as a thermosetting resin formed by the condensation reaction of phenols and formaldehyde. The phenolic resin serves as a source of carbon (C) in the nitriding process. The phenolic resin exists in a solid state and has a property of dissolving in acetone. The phenolic resin solution preferably has a solid content (phenolic resin) of 2 to 50% by weight based on 100% by weight of the phenolic resin solution in view of the dispersibility, viscosity and long-term storage of the phenolic resin.

The sol containing the aluminum source and the phenolic resin solution are mixed. The sol and the phenol resin solution are mixed so that the aluminum source contained in the sol and the phenol resin contained in the phenol resin solution are in a ratio of 1: 0.42 to 3, preferably 5: 5 to 7: 3 by weight . By such mixing, the aluminum source particles are coated with a phenol resin to form a structure surrounded.

When the sol and the phenol resin solution are sufficiently mixed, a heat treatment process is performed. The heat treatment process is preferably performed at a temperature of 60 ° C to 600 ° C, preferably 350 ° C to 500 ° C. In the heat treatment process, first heat treatment is performed at a temperature of about 60 to 150 DEG C to remove a solvent component, and in order to remove the organic solvent from the liquefied phenol resin and to remove the OH group in the phenol resin, And a step of performing a secondary heat treatment at a temperature of from 600 to 600 占 폚 (preferably from 350 to 500 占 폚). When the heat treatment temperature is less than 60 캜, it is difficult to evaporate the solvent components, and when the heat treatment is performed at a high temperature exceeding 600 캜, energy consumption is high and carbon is oxidized, which is uneconomical. The heat treatment is preferably performed in an oxidizing atmosphere such as air for 1 to 72 hours. By the heat treatment process, the mixed solution of the sol and the phenol resin solution becomes a gel and becomes a lump in the form of a lump.

Nitridation of the resultant after the heat treatment process. The nitriding treatment is preferably performed at a temperature of about 1,400 to 1,800 ° C., preferably about 1,500 to 1,700 ° C., for 10 minutes to 72 hours while injecting a reaction gas containing a nitrogen component. It is preferable that the reaction gas serving as a nitrogen source in the nitridation treatment is a nitrogen (N ₂ ) gas or a mixed gas of nitrogen (N ₂ ) and hydrogen (H ₂ ). The reaction gas reacts with an aluminum source to act as a nitrogen source to form aluminum nitride (AlN). The reaction gas serving as the nitrogen source may be a nitrogen gas (N ₂ ) gas alone, but may be a mixture gas of nitrogen (N ₂ ) and hydrogen (H ₂ ) in a volume ratio of 90:10 to 99.9: 0.1 Is preferably used. When a mixed gas of nitrogen (N ₂ ) and hydrogen (H ₂ ) is used as the reaction gas, it is preferable in terms of reaction stabilization of the aluminum component and the nitrogen component, aspect of high purity aluminum nitride formation and minimization of residual oxygen. It is preferable to flow a nitrogen (N ₂ ) gas or a mixed gas of nitrogen (N ₂ ) and hydrogen (H ₂ ) at a flow rate of 0.1 to 10 L / min, preferably 1 to 5 L / min.

The aluminum (Al) component of an aluminum source such as boehmite (AlOOH) reacts with the nitrogen component of the reaction gas to synthesize aluminum nitride (AlN). The reaction formula for forming aluminum nitride (AlN) in the case of using alumina (Al ₂ O ₃ ) as the aluminum source is shown in the following reaction formula 1, and the formation of aluminum nitride (AlN) in the case of using boehmite The reaction scheme is shown in Scheme 2 below.

[Reaction Scheme 1]

_{Al 2 O 3 + 3C + N} 2 → 2AlN + 3CO

[Reaction Scheme 2]

_{2AlOOH + 3C + N 2 → 2AlN} + 3CO + H 2 O

When a reaction gas a mixed gas of nitrogen (N ₂₎ and hydrogen (H _2), hydrogen in the nitriding treatment process (H ₂₎ may serve to reduce the residual oxygen by the trap (trap) the oxygen component and the reducing agent act .

During the nitriding process, the particles of the aluminum source are surrounded and surrounded by a phenolic resin, so that the carbon (C) component surrounding the particles of the aluminum source serves to trap the oxygen component present in the aluminum source, And the oxygen component react with each other to be converted into carbon monoxide (CO) and discharged. The amount of oxygen remaining in the synthesized aluminum nitride (AlN) can be minimized by coating the respective aluminum source particles with a liquid phenolic resin solution, and the carbon components of the phenolic resin react with oxygen to form carbon monoxide (CO) So that the decarburization process can be performed at a low temperature after the nitriding process, and the decarburization process can be completed within a short time. In the case of using a carbon material of a solid phase such as carbon black, it is difficult to uniformly mix with an aluminum source, so that the nitriding treatment is not carried out in part, so that there is a large amount of residual oxygen locally, or aluminum nitride However, nitriding can be carried out not only on the surface of the aluminum source particles but also on the surface (bulk) of the aluminum source by coating the respective particles of the aluminum source with a liquid phenolic resin solution, Aluminum nitride (AlN) can be synthesized.

A pulverizing step of pulverizing the nitrided product to a target particle size may be carried out. The pulverization process may be performed by various methods such as jet mill, ball milling, trigger milling and the like. To describe the ball milling process as an example, the nitrided product is charged into a ball milling machine to uniformly crush the nitrided product, and is mechanically uniformly pulverized by rotating it at a constant speed using a ball milling machine. The ball used for ball milling may be a ball made of ceramics such as alumina or zirconia, and the balls may be all the same size or may be used together with balls having two or more sizes. The size of the ball, the milling time, and the rotation speed per minute of the ball miller. For example, the size of the ball may be set in the range of about 1 mm to 10 mm, the rotational speed of the ball miller may be set in the range of about 50 to 500 rpm, and the ball milling is preferably performed for 1 to 48 hours .

The nitrided product is decarburized in an oxidizing atmosphere to obtain aluminum nitride (AlN) powder of high purity. The decarburization treatment process can be performed in the following manner.

The nitrided product is charged into a furnace such as an electric furnace, and the temperature is raised to a target decarburization treatment temperature. In this case, it is preferable that the temperature rise rate of the furnace is about 1 to 50 DEG C / min. If the temperature rise rate of the furnace is too slow, it takes a long time to decrease the productivity. If the temperature rise rate of the furnace is too fast, it is preferable to increase the temperature of the furnace at the heating rate within the above range. At this time, it is preferable that the pressure in the furnace is maintained at normal pressure.

When the temperature of the furnace rises to the target decarburization treatment temperature, it is maintained for a predetermined time (for example, 10 minutes to 24 hours). The decarburization treatment is preferably performed in an oxidizing atmosphere such as oxygen (O ₂ ) and air. If a certain period of time is maintained at the decarburization treatment temperature, the remaining carbon (C) component is removed and high purity aluminum nitride (AlN) can be obtained. In the case of supplying oxygen (O ₂ ) gas during the decarburization treatment, it is preferable to flow the oxygen (O ₂ ) gas at a flow rate of about 0.1 to 20 L / min, preferably about 1 to 5 L / min.

If the decarburization treatment temperature is too high, the energy is consumed so much that it is uneconomical. If the decarburization treatment temperature is too low, the residual carbon The component (C) may not be removed. Therefore, it is preferable to carry out the treatment at the decarburization treatment temperature in the above range.

After the decarburization process is performed, the furnace temperature is lowered to unload the aluminum nitride (AlN) powder. The furnace cooling may be effected by shutting down the furnace power source to cool it in a natural state, or optionally by setting a temperature decreasing rate (for example, 10 DEG C / min). It is preferable to keep the pressure inside the furnace constant even while the furnace temperature is being lowered.

Hereinafter, embodiments according to the present invention will be described in more detail, and the present invention is not limited to the following embodiments.

≪ Example 1 >

A sol having 4 kg of aluminum hydroxide (Al (OH) ₃ ) as an aluminum source was dispersed in 10 liters of ethanol as an organic solvent. Aluminum hydroxide (Al (OH) ₃ ) was powder having an average particle diameter of 1 탆. The sol was added with a nitric acid (HNO ₃ ) solution to achieve a pH of about 2. The nitric acid (HNO ₃ ) solution was a solution having a concentration of nitric acid (HNO ₃ ) of 33%.

1.2 kg of a phenol resin was dissolved in 1 liter of acetone to form a phenol resin solution.

The sol containing aluminum hydroxide (Al (OH) ₃ ) and the phenolic resin solution were mixed.

The mixed solution of the sol and the phenol resin solution was subjected to a heat treatment process. The heat treatment process was performed by performing a primary heat treatment at a temperature of 80 ° C. for 10 hours and a secondary heat treatment at a temperature of 500 ° C. for 5 hours in order to partially remove the solvent component. The heat treatment was performed in an air atmosphere.

The resulting product was subjected to a heat treatment process and was nitrided in a graphite crucible. In the nitriding process, the resultant is subjected to a heat treatment process, charged into a graphite crucible, charged into a vacuum electric furnace, operated by a rotary pump to evacuate the vacuum furnace, and then nitrogen (N ₂ ) After the gas was purged, the temperature of the vacuum electric furnace was raised to 1700 ° C at a rate of 10 ° C / min and a mixed gas of nitrogen (N ₂ ) and hydrogen (H ₂ ) was supplied at a flow rate of about 1 l / min at 1700 ° C Followed by flowing for 2 hours. The mixed gas was a gas in which nitrogen (N ₂ ) and hydrogen (H ₂ ) were mixed at a volume ratio of 97: 3.

The nitrided resultant was pulverized for one hour with induction.

The pulverized product was decarburized in an oxidizing atmosphere to obtain aluminum nitride (AlN) powder. In the decarburization treatment, the pulverized product was placed in an alumina crucible and charged into an electric furnace (box furnace). The temperature of the electric furnace was raised to 750 ° C at a rate of 10 ° C / min. Flow rate for 5 hours.

<Example 2>

A sol having 4 kg of aluminum source in boehmite (AlOOH) dispersed in 10 liters of ethanol as an organic solvent was formed. A boehmite (AlOOH) powder having an average particle diameter of 50 nm was used. The sol was added with a nitric acid (HNO ₃ ) solution to achieve a pH of about 2. The nitric acid (HNO ₃ ) solution was a solution having a concentration of nitric acid (HNO ₃ ) of 33%.

1.2 kg of a phenol resin was dissolved in 1 liter of acetone to form a phenol resin solution.

The sol containing the boehmite (AlOOH) and the phenol resin solution were mixed.

The mixed solution of the sol and the phenol resin solution was subjected to a heat treatment process. The heat treatment process was performed by performing a primary heat treatment at a temperature of 80 ° C. for 10 hours and a secondary heat treatment at a temperature of 500 ° C. for 5 hours in order to partially remove the solvent component. The heat treatment was performed in an air atmosphere.

The resulting product was subjected to a heat treatment process and was nitrided in a graphite crucible. In the nitriding process, the resultant is subjected to a heat treatment process, charged into a graphite crucible, charged into a vacuum electric furnace, operated by a rotary pump to evacuate the vacuum furnace, and then nitrogen (N ₂ ) After the gas was purged, the temperature of the vacuum electric furnace was raised to 1700 ° C at a rate of 10 ° C / min and a mixed gas of nitrogen (N ₂ ) and hydrogen (H ₂ ) was supplied at a flow rate of about 1 l / min at 1700 ° C Followed by flowing for 2 hours. The mixed gas was a gas in which nitrogen (N ₂ ) and hydrogen (H ₂ ) were mixed at a volume ratio of 97: 3.

The nitrided resultant was pulverized for one hour with induction. The milling was carried out so as to have a particle size enough to pass through a sieve of 100 mesh.

The pulverized product was decarburized in an oxidizing atmosphere to obtain aluminum nitride (AlN) powder. In the decarburization treatment, the pulverized product was placed in an alumina crucible and charged into an electric furnace (box furnace). The temperature of the electric furnace was raised to 750 ° C at a rate of 10 ° C / min. Flow rate for 5 hours.

FIGS. 1 and 2 are scanning electron microscope (SEM) photographs of aluminum nitride (AlN) powders prepared according to Example 1 and FIGS. 3 and 4 are photographs of aluminum nitride ) SEM photograph of the powder.

Referring to FIGS. 1 to 4, when aluminum hydroxide (Al (OH) ₃ ) is used as an aluminum source, aggregation of particles is observed, and a relatively large aluminum nitride powder having a particle size of about 0.5 to 3 μm is obtained When aluminum source boehmite (AlOOH) was used, the particles were not agglomerated and fine aluminum nitride powders with particle sizes of about 10 to 200 nm could be obtained.

5 is a graph showing an X-ray diffraction (XRD) pattern of aluminum nitride (AlN) powder produced according to Example 2. Fig. FIG. 5 (a) shows the X-ray diffraction pattern after the nitriding treatment, and FIG. 5 (b) shows the X-ray diffraction pattern after the decarburization treatment.

Referring to FIG. 5, only an aluminum nitride (AlN) crystal phase was observed to be present.

FIG. 6 is a graph showing the particle size analysis of the aluminum nitride (AlN) powder produced according to Example 2. Table 1 below shows the particle size analysis results.

Vm 3.15 [Cm 3 (STP) g ^-1 ] a _{s . BET} 13.7 [M 2 g ^-1 ] C 99.6 Total pore volume (p / p ₀ = 0.304) 0.0068 [Cm ³ g ^-1 ] Average pore diameter 1.99 [Nm]

The content of residual oxygen in the aluminum nitride (AlN) powder prepared according to Example 2 was 0.79 to 1.0 wt%, and the content of residual carbon in the aluminum nitride (AlN) powder prepared according to Example 2 As a result, it was about 200 ppm.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

Claims (10)

Forming an aluminum source containing an aluminum (Al) component in a sol dispersed in an organic solvent;
Forming a phenol resin solution in which the phenol resin is dissolved;
Mixing the sol with the phenolic resin solution to cause particles of the aluminum source to be coated with the phenolic resin;
Heat-treating the mixed solution of the sol and the phenol resin solution;
Nitriding the heat-treated product while injecting a reaction gas containing a nitrogen component to synthesize aluminum nitride (AlN); And
A method of producing aluminum nitride comprising the step of decarburizing to remove residual carbon contained in the nitrided result.
The method according to claim 1, wherein the aluminum source uses at least one powder selected from alumina (Al ₂ O ₃ ), aluminum hydroxide (Al (OH) ₃ ) and boehmite (AlOOH) Way.
The method according to claim 1, wherein the aluminum source uses boehmite (AlOOH) powder having an average particle diameter of 10 to 50 nm.
The method according to claim 1, wherein the sol and the phenol resin solution are mixed so that the aluminum source contained in the sol and the phenol resin contained in the phenol resin solution are in a ratio of 1: 0.42 to 3 by weight, Method of manufacturing aluminum.
The method according to claim 1, wherein a sol of nitric acid (HNO ₃ ) solution is added to improve the dispersibility of the aluminum source to form the sol having a pH ranging from 1 to 4.
The method of claim 1, wherein the heat treatment is performed in an oxidizing atmosphere at a temperature of 350 ~ 500 ℃.
The method of claim 1, wherein the reaction gas serving as a nitrogen source uses a mixed gas in which nitrogen (N ₂ ) and hydrogen (H ₂ ) are mixed in a ratio of 90:10 to 99.9: 0.1 by volume, and nitriding treatment process. In hydrogen (H ₂ ) acts as a reducing agent to trap the oxygen component contained in the aluminum source (trap) to reduce the residual oxygen, the method of producing aluminum nitride.
The method according to claim 1, wherein the nitriding treatment is performed at a temperature of 1500 to 1700 占 폚.
The method according to claim 1, wherein the decarburization treatment is performed in an oxidizing atmosphere at a temperature of 650 to 800 ° C.
The method for producing aluminum nitride according to claim 1, wherein an oxygen (O ₂ ) gas is flowed at a flow rate of 0.1 to 20 L / min during the decarburization treatment.

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