KR101970952B1 - Manufacturing method of plasma resistant and conductive ceramic-nanocarbon composite - Google Patents

Abstract

The present invention relates to a method of manufacturing a metal-oxide-ceramic composite material, wherein ceramic is a matrix, nano-carbon coated with a metal oxide is dispersed in the matrix, and the metal oxide comprises at least one material selected from the group consisting of MgO and ZrO ₂ , Wherein the ceramic comprises at least one material selected from the group consisting of Al ₂ O ₃ , ZrO ₂ , AlN, SiC and Si ₃ N _4, and a process for producing the same . According to the ceramic-nano-carbon composite of the present invention, since the plasma oxide is coated on the surface of the nano-carbon which is excellent in conductivity but is vulnerable to a plasma environment, it has plasma resistance and conductivity.

Description

[0001] The present invention relates to a method for manufacturing a plasma-conductive ceramic-nano-carbon composite,

The present invention relates to a ceramic-nano-carbon composite and a method of manufacturing the same, and more particularly, to a ceramic-nano-carbon composite having plasma and conductivity.

In the semiconductor manufacturing process, an etching apparatus, a sputtering apparatus, a CVD (chemical vapor deposition) apparatus, and the like are used, and these apparatuses include a plasma generating apparatus. The gas used in the semiconductor manufacturing process uses a halogen-based corrosion gas such as a fluorine-based or chlorine-based gas. Utilizing the high reactivity of the gas, the gas is used for etching an insulating film and a resist film.

The fluorine-based gases in the reactive gas include SF ₆ , CF ₄ , CHF ₃ , and HF. The chlorine-based gases include Cl ₂ , CCl ₄ , and SiCl _4. These gases are converted into plasma by microwave or high- .

The inner material of such a device requires high plasma resistance. Ceramics such as SiO ₂ , Al ₂ O ₃ , Si ₃ N ₄ , Y ₂ O _3, and AlN are used as a material for imparting corrosion resistance to a halogen-based gas or a plasma thereof.

These ceramics are high-resistance insulators, which cause abnormal discharges inside the plasma chamber, which is subjected to a high voltage, thereby causing particles to be generated. Due to such a problem, it is necessary to introduce a conductive plasma ceramic material having a low electric resistance.

Korean Patent Registration No. 10-1175756

The present invention provides a ceramic-nano-carbon composite having plasma resistance and conductivity because the plasma oxide is coated on the surface of the nano-carbon which is excellent in conductivity but is vulnerable to a plasma environment.

Another object to be solved by the present invention is to provide a method for manufacturing a ceramic-nano-carbon composite by coating a nano-carbon surface with a plasma oxide in order to improve the plasma resistance of the nano-carbon, .

The present invention relates to a method of manufacturing a metal-oxide-ceramic composite material, wherein ceramic is a matrix, nano-carbon coated with a metal oxide is dispersed in the matrix, and the metal oxide comprises at least one material selected from the group consisting of MgO and ZrO ₂ , Wherein the ceramic comprises at least one material selected from the group consisting of Al ₂ O ₃ , ZrO ₂ , AlN, SiC and Si ₃ N ₄ .

The nano-carbon may be at least one carbon selected from the group consisting of graphene, graphene oxide and exfoliated graphite, and may have a thickness of 0.2 to 50 nm.

The nano-carbon coated with the metal oxide may be 0.1 to 10 parts by weight based on 100 parts by weight of the ceramic.

The nano-carbon coated with the metal oxide is distributed in a grainboundary part between the ceramic particles, and the ratio of the distribution of the nano-carbon coated with the metal oxide to the grainboundary part between the ceramic particles is within the matrix Gt; 80% < / RTI > for the total dispersed content.

The present invention also provides a method for producing a metal salt, comprising the steps of: (a) adding a metal salt containing at least one metal selected from the group consisting of Mg and Zr to an alcohol to form a metal salt solution; (b) (C) mixing and reacting the metal salt solution with the nano-carbon slurry, and (d) reacting the nano-carbon slurry with 1 A step of coating the metal hydroxide on the surface of the nano-carbon while nucleation and growth of a metal hydroxide containing at least nano metal is performed; and (e) drying the nano-carbon slurry containing the metal hydroxide-coated nano- (F) heating the nano-carbon coated with the metal hydroxide to heat the metal (G) mixing and molding the nano-carbon coated with the metal oxide and the ceramic powder, and (h) sintering the resultant to obtain a ceramic-nano-carbon composite. Wherein the ceramic-nano-carbon composite comprises a ceramic matrix, nano-carbon coated with the metal oxide is dispersed in the matrix, and the metal oxide is one selected from the group consisting of MgO and ZrO ₂ Wherein the ceramic powder comprises at least one material selected from the group consisting of Al ₂ O ₃ , ZrO ₂ , AlN, SiC, and Si ₃ N _{4. The} plasma-resistant conductive ceramic-nano-carbon A method for producing a composite is provided.

The nano-carbon may be at least one carbon selected from the group consisting of graphene, graphene oxide and exfoliated graphite, and may have a thickness of 0.2 to 50 nm.

The metal salt including at least one metal selected from the group consisting of Mg and Zr may include at least one material selected from the group consisting of MgCl ₂ , MgNO ₃ , ZrCl ₄ and Zr (NO ₃ ) ₂ .

The alcohol may be a mono-to 5-valent alcohol compound or a derivative thereof.

In the step (c), the metal salt solution and the nano-carbon slurry are mixed so that the metal salt is 100 to 500 parts by weight based on 100 parts by weight of the nano-carbon.

In the step (g), the nano-carbon coated with the metal oxide may be mixed in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the ceramic powder.

The heat treatment is preferably performed at a temperature of 350 to 400 캜.

The binder and the dispersant may be further mixed in step (g), and the sintering may be performed by raising the temperature to a first temperature of 600 to 900 캜 to pyrolyze the binder, holding the mixture at the first temperature, Raising the temperature to a second temperature of 1600-1900 deg. C higher than the first temperature, and sintering while maintaining the second temperature.

According to the ceramic-nano-carbon composite of the present invention, since the plasma oxide is coated on the surface of the nano-carbon which is excellent in conductivity but is vulnerable to a plasma environment, it has plasma resistance and conductivity.

In order to improve the plasma resistance of nanocarbon which is excellent in conductivity but is vulnerable to a plasma environment, the surface of the nano-carbon is coated with a plasma-resistant oxide and the ceramic-nano-carbon composite can be manufactured using the plasma oxide. Nano-carbon is a material vulnerable to a plasma environment, but the plasma resistance can be improved by coating the surface of the nano-carbon with a plasma-resistant oxide made of MgO, ZrO ₂ or a mixture thereof. The metal oxide coating exhibits an effect of improving the plasma resistance of the nano-carbon.

1 is a scanning electron microscope (SEM) photograph showing the microstructure of an Al ₂ O ₃ -nano-carbon composite.
2 is a schematic diagram showing a state in which a nano-carbon coated with a metal oxide is dispersed in a ceramic matrix.
3A and 3B are transmission electron microscope (TEM) photographs showing the microstructure of MgO-coated nano-carbon.
FIG. 4 is a graph showing the result of EDX (Energy Dispersive X-ray Analysis) analysis of a component of MgO-coated nano-carbon.
5 is a scanning electron microscope (SEM) photograph showing the microstructure of the Al ₂ O ₃ -nano-carbon composite using nano-carbon coated with MgO after the plasma etching test.
6 is a scanning electron microscope (SEM) photograph showing the microstructure of the Al ₂ O ₃ -nano carbon composite using nano-carbon which is not coated with MgO after the plasma etching test.

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.

Hereinafter, 'carbon' is used to mean graphene, graphene oxide, exfoliated graphite, or a mixture thereof and is referred to as 'nano carbon'. Means carbon having a thickness of 0.2 to 50 nm.

The plasma-resistant conductive ceramic-nano-carbon composite according to a preferred embodiment of the present invention is characterized in that ceramic is a matrix, nano-carbon coated with metal oxide is dispersed in the matrix, and the metal oxide is MgO and ZrO ₂ , and the ceramic comprises at least one material selected from the group consisting of Al ₂ O ₃ , ZrO ₂ , AlN, SiC and Si ₃ N ₄ .

The nano-carbon may be at least one carbon selected from the group consisting of graphene, graphene oxide and exfoliated graphite, and may have a thickness of 0.2 to 50 nm.

The nano-carbon coated with the metal oxide may be 0.1 to 10 parts by weight based on 100 parts by weight of the ceramic.

The nano-carbon coated with the metal oxide is distributed in a grainboundary part between the ceramic particles, and the ratio of the distribution of the nano-carbon coated with the metal oxide to the grainboundary part between the ceramic particles is within the matrix Gt; 80% < / RTI > for the total dispersed content.

A method of manufacturing a plasma-resistant conductive ceramic-nano-carbon composite according to a preferred embodiment of the present invention comprises the steps of: (a) adding a metal salt containing at least one metal selected from the group consisting of Mg and Zr to an alcohol to form a metal salt solution; (B) adding nano-carbon and an amine compound to an alcohol to form a nanocarbon slurry; (c) mixing and reacting the metal salt solution and the nanocarbon slurry; and (d) Wherein the metal hydroxide is coated on the surface of the nano-carbon while growing and growing nuclei of a metal hydroxide containing at least one metal selected from the group consisting of Mg and Zr on the surface of the nano- Drying a nanocarbon slurry comprising a nanocarbon coated with a metal hydroxide to obtain a nanocarbon coated with the metal hydroxide (F) converting the metal hydroxide into a metal oxide by heat treating the metal hydroxide coated nanocarbon; (g) mixing and molding the nanocarbon coated with the metal oxide and the ceramic powder; and (h) sintering the molded product to obtain a ceramic-nano-carbon composite, wherein the ceramic-nano-carbon composite comprises a ceramic matrix, and the nano-carbon coated with the metal oxide is contained in the matrix Wherein the metal oxide comprises at least one material selected from the group consisting of MgO and ZrO ₂ , and the ceramic powder is selected from the group consisting of Al ₂ O ₃ , ZrO ₂ , AlN, SiC and Si ₃ N ₄ Include one or more materials.

The nano-carbon may be at least one carbon selected from the group consisting of graphene, graphene oxide and exfoliated graphite, and may have a thickness of 0.2 to 50 nm.

The metal salt including at least one metal selected from the group consisting of Mg and Zr may include at least one material selected from the group consisting of MgCl ₂ , MgNO ₃ , ZrCl ₄ and Zr (NO ₃ ) ₂ .

The alcohol may be a mono-to 5-valent alcohol compound or a derivative thereof.

In the step (c), the metal salt solution and the nano-carbon slurry are mixed so that the metal salt is 100 to 500 parts by weight based on 100 parts by weight of the nano-carbon.

In the step (g), the nano-carbon coated with the metal oxide may be mixed in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the ceramic powder.

The heat treatment is preferably performed at a temperature of 350 to 400 캜.

The binder and the dispersant may be further mixed in step (g), and the sintering may be performed by raising the temperature to a first temperature of 600 to 900 캜 to pyrolyze the binder, holding the mixture at the first temperature, Raising the temperature to a second temperature of 1600-1900 deg. C higher than the first temperature, and sintering while maintaining the second temperature.

Hereinafter, a method of manufacturing the plasma-resistant conductive ceramic-nano-carbon composite according to a preferred embodiment of the present invention will be described in more detail.

Table 1 below shows the plasma resistance of typical ceramics.

Material Etch rate (cm / min) SiC (pressureless sintering) 7.0 × 10 ^-6 SiC (CVD) 7.2 x 10 ^-6 MgO 7.6 × 10 ^-8 Y ₂ O ₃ 5.0 × 10 ^-8 Al ₂ O ₃ doped Y ₂ O ₃ 2.1 × 10 ^-7 ZrO ₂ 6.6 × 10 ^-7 Al ₂ O ₃ 1.3 x 10 ^-6 Si wafer 1.1 x 10 ^-5 Sapphire wafer 1.0 x 10 ^-6

As shown in Table 1, the Si wafer, which is a semiconductor material, exhibits an etch rate of 1.1 × 10 ^-5 cm / min, and the typical ceramic material shown in Table 1 is 10 to 100 times And has plasma resistance. Comparing the plasma resistance of the oxide ceramics, Y ₂ O ₃ >MgO> ZrO ₂ > Al ₂ O ₃ can be listed in that order. In the case of Y ₂ O _3, the plasma resistance is 26 times that of Al ₂ O ₃ And exhibits plasma resistance of 137 times as compared with the Si wafer.

Ceramic materials, such as SiO ₂ , Al ₂ O ₃ , Si ₃ N ₄ , Y ₂ O ₃ and AlN, are generally high resistivities of 10 ¹³ Ωcm or more.

Nano-carbon is a highly conductive material, for example, in the case of graphene sheets, the electrical resistance is 10 ^-6 Ωcm, which is about 100 times better than copper.

When a ceramic-nano-carbon composite is prepared by adding 0.1 to 5 wt% of nano-carbon, which is a highly conductive material, to a high-resistance ceramic such as Al ₂ O ₃ , a conductive ceramic can be manufactured by lowering the electrical resistance of the ceramic.

Table 2 below shows the electrical resistivity of the Al ₂ O ₃ -nano-carbon composite according to the nano-carbon content.

Psalm name Al ₂ O ₃ Al ₂ O ₃ + Oxidized graphene 0.1% Al ₂ O ₃ + Graphite 2.6% Al ₂ O ₃ + Oxidized graphene 0.5% Al ₂ O ₃ + Oxidized graphene 1.0% Electrical resistance
(Ωcm) > 10 ¹⁵ 10 ¹² 10 ⁴ <10 ³ <10 ³

Referring to Table 2, Al ₂ O ₃ is an insulator having an electrical resistance of 10 ¹⁵ Ωcm or more, but when the graphene oxide is added by 0.1 wt%, the electrical resistance decreases to 10 ¹² Ωcm, An Al ₂ O ₃ - nanocarbon composite showed an electrical resistance of less than 10 ³ Ωcm. In the case of Al ₂ O ₃ - nanocarbon composites prepared by adding graphite, electrical resistivity was 10 ⁴ Ωcm when added more than 2.6 wt%.

FIG. 1 shows the result of observing the microstructure of the Al ₂ O ₃ -nano-carbon composite. It was confirmed that nano-carbon was dispersed and distributed in the base Al ₂ O ₃ . It is possible to manufacture conductive ceramics by lowering the electrical resistance of the ceramic nano-carbon dispersed.

Table 3 below shows the etch rate of the Al ₂ O ₃ -nano-carbon composite according to the nano-carbon content.

Psalm name Al ₂ O ₃ Al ₂ O ₃ + Oxidized graphene 0.1% Al ₂ O ₃ + Graphite 2.6% Al ₂ O ₃ + Oxidized graphene 0.5% Al ₂ O ₃ + Oxidized graphene 1.0% Etch rate
(cm / min) 1.3 x 10 ^-6 2.7 × 10 ^-6 5.3 × 10 ^-6 3.0 x 10 ^-6 1.4 x 10 ^-5

Referring to Table 3, Al ₂ O ₃ exhibited an etch rate of 1.3 × 10 ^-6 cm / min. If yes oxide was added to the pin, the 0.1 wt% 2.7 × 10 ^-6 cm / min showed an etching rate of, 0.5 wt% The addition was prepared by adding ^{3.0 × 10 -6 cm / min,} 1.0 wt% Al 2 O ₃ - nano carbon composite showed an etching rate of 1.4 × 10 ^-5 cm / min. In the case of Al ₂ O ₃ - nano carbon composite prepared by adding graphite, the etching rate was 5.3 × 10 ^-6 cm / min at 2.6 wt%.

The etching rate tended to increase in proportion to the content of nano-carbon added. This is a result of reflecting the weak plasma resistance of nano-carbon.

Nano-carbon is a very useful additive for controlling the electrical resistance of ceramics, but it is a material vulnerable to the plasma environment.

In order to improve the plasma resistance of the ceramic-nano-carbon composite, it is possible to solve this problem by coating the surface of the nano-carbon having weak plasma resistance with an inner plasma oxide made of MgO, ZrO ₂ or a mixture thereof.

In order to prepare the ceramic-nano-carbon composite according to the preferred embodiment of the present invention, a metal salt solution containing at least one metal selected from the group consisting of Mg and Zr is added to the alcohol to form a metal salt solution.

The metal salt containing at least one metal selected from the group consisting of Mg and Zr may be chloride, nitrate or the like containing magnesium (Mg), chloride, nitrate or the like containing zirconium (Zr) ) And zirconium (Zr). More specifically hydrochloride containing the magnesium (Mg) is MgCl ₂ can be, nitrates, including the magnesium (Mg) may be a MgNO _3, hydrochloride containing the zirconium (Zr) is ZrCl ₄ days And the nitrate containing zirconium (Zr) may be Zr (NO ₃ ) ₂ .

The alcohol may be a mono-to 5-valent alcohol compound or a derivative thereof.

Nano-carbon and amine compounds are added to the alcohol to form a nano-carbon slurry. The nano-carbon may be at least one carbon selected from the group consisting of graphene, graphene oxide and exfoliated graphite, and may have a thickness of 0.2 to 50 nm. The amine compound may be methylamine, ethylamine, dimethylamine, diethylamine, and the like. The mixing of the amine compound with the nanocarbon is performed by coating the surface of the nanocarbon with an amine compound to induce nucleation of the metal hydroxide (coating agent) on the surface of the nanocarbon so that coating by heterogeneous nucleation occurs . When an amine compound is added after the metal salt solution and the nanocarbon slurry are mixed, the metal hydroxide (coating agent) such as Mg (OH) ₂ , Zr (OH) ₄ Nucleation of the metal hydroxide (coating agent) occurs in the mixed solution of the metal salt solution and the nanocarbon slurry without nucleation, and the metal hydroxide (coating agent) is not coated on the surface of the nanocarbon particle to be coated, . The amine compound is preferably mixed at 1 to 10 ml with respect to 1 g of nano-carbon.

The metal salt solution and the nano-carbon slurry are mixed and reacted. The metal salt solution and the nano-carbon slurry are mixed so that the metal salt is 100 to 500 parts by weight based on 100 parts by weight of the nano-carbon.

By the reaction, the metal hydroxide containing at least one metal selected from the group consisting of Mg and Zr is nucleated and grown on the surface of the nano-carbon, and the metal hydroxide is coated on the surface of the nano-carbon. The metal hydroxide may be Mg (OH) ₂ , Zr (OH) _4, or a mixture thereof.

The nano-carbon slurry containing the nano-carbon coated with the metal hydroxide is dried to obtain a nano-carbon coated with the metal hydroxide. The drying is preferably performed in an oven at 60 to 150 캜, more preferably at 80 to 120 캜 for 1 to 48 hours, more preferably 6 to 24 hours.

The nanocarbon coated with the metal hydroxide is heat-treated. The metal hydroxide is converted into a metal oxide by the heat treatment. The metal oxide includes at least one material selected from the group consisting of MgO and ZrO ₂ . The heat treatment is preferably performed at a temperature of 350 to 400 DEG C in air (in an oxidizing atmosphere), and preferably in a non-oxidizing atmosphere at 600 to 800 DEG C in order to obtain a metal oxide having improved crystallinity. The metal hydroxide may not be converted into a metal oxide at a temperature lower than 350 ° C. and the nano-carbon may be oxidized at a temperature higher than 400 ° C. in an oxidizing atmosphere. By the heat treatment, a nano-carbon coated with a metal oxide can be obtained. The metal oxide coating exhibits an effect of improving the plasma resistance of the nano-carbon. Nano-carbon is a material vulnerable to a plasma environment, but it is possible to solve this problem by coating the surface of the nano-carbon with an inner plasma oxide made of MgO, ZrO ₂ or a mixture thereof. The heat treatment is preferably performed in an oxidizing gas atmosphere, an inert gas atmosphere, or a vacuum atmosphere.

The nano-carbon coated with the metal oxide and the ceramic powder are mixed and molded. The nano-carbon coated with the metal oxide is preferably mixed with 0.1 to 15 parts by weight with respect to 100 parts by weight of the ceramic powder. At this time, the dispersant and the binder may be further mixed. The dispersant may be Cerasperse 5468CF or the like. It is preferable that the dispersant is mixed in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the ceramic powder. The binder may be PVA (polyvinylalcohol) or the like. It is preferable that the binder is mixed in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the ceramic powder.

The mixing may be performed by various methods such as ball mill, planetary mill, attrition mill, and the like. Hereinafter, the mixing process by the ball mill method will be described in detail. The nano-carbon coated with the metal oxide and the ceramic powder are charged into a ball milling machine and mixed. The raw material is uniformly mixed by rotating it at a constant speed using a ball milling machine. The ball used for the ball mill may be a ball made of a ceramic 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 balls may be set in the range of about 1 mm to 50 mm in consideration of the size of the particles, and the rotational speed of the ball miller may be set in the range of about 100 to 1000 rpm. The ball mill is preferably carried out for 1 to 24 hours in consideration of the size of the target particle and the like. The nano-carbon coated with the metal oxide and the ceramic powder are uniformly mixed by the ball mill.

The molding can be performed by a variety of known methods such as slip casting, pressure molding, cold isostatic pressure (CIP), and a combination thereof.

The molded product is sintered. After the sintering, the ceramic-nano-carbon composite can be obtained. The sintering is preferably performed at a temperature of 1600 to 1900 ° C. The sintering is preferably performed in an inert gas atmosphere. The sintering is preferably performed at a temperature of 1600 to 1900 ° C. If the sintering temperature is less than 1600 ° C, the thermal or mechanical properties of the sintered body may be poor due to incomplete sintering. If the temperature exceeds 1900 ° C, energy consumption is high, This may not be good. The sintering temperature is preferably raised at a heating rate of 1 to 50 ° C / min. If the heating rate is too slow, it takes a long time to decrease the productivity. If the heating rate is too high, thermal stress is applied due to a rapid temperature rise It is preferable to raise the temperature at the temperature raising rate in the above range. The sintering is preferably carried out at a sintering temperature for 10 minutes to 24 hours, more preferably 1 to 12 hours. If the sintering time is too long, the energy consumption is high, so it is not economical and further sintering effect is not expected. If the sintering time is short, the physical properties of the sintered body may not be good due to incomplete sintering.

Wherein the binder is heated to a first temperature of 600-900 ° C to pyrolyze the binder and maintained at the first temperature and a second temperature of 1600-1900 ° C higher than the first temperature And sintering while maintaining at the second temperature. The holding at a first temperature of 600 to 900 DEG C is performed in order to perform a degreasing process for removing the organic metal oxide since organic additives such as a dispersant and a binder are contained in the molded body in addition to raw material powders such as nano carbon and ceramic powder coated with a metal oxide . The temperature is raised to 600 ~ 900 ℃ and the air is injected into the electric furnace to burn and remove the organic additives. However, Al ₂ O ₃ - nano carbon composite contains nano carbon, It is preferable to perform the operation while injecting an inert gas such as nitrogen (N ₂ ) or argon (Ar) into the vacuum furnace.

2 is a schematic diagram showing a state in which a nano-carbon coated with a metal oxide is dispersed in a ceramic matrix.

Referring to FIG. 2, in the ceramic-nano-carbon composite produced by the above-described method, ceramic is a matrix, and nano-carbon coated with the metal oxide is dispersed in the matrix. The nano-carbon coated with the metal oxide is distributed in a grainboundary part between the ceramic particles, and the ratio of the distribution of the nano-carbon coated with the metal oxide to the grainboundary part between the ceramic particles is within the matrix Gt; 80% &lt; / RTI &gt; for the total dispersed content. The metal oxide includes at least one material selected from the group consisting of MgO and ZrO ₂ .

Hereinafter, experimental examples according to the present invention will be specifically shown, and the present invention is not limited to the following experimental examples.

<Experimental Example>

In the experimental example of the present invention, graphite and oxide graphene peeled off with a nano-carbon material were selected, and Al ₂ O ₃ The conductive Al ₂ O ₃ - nanocarbon composites were prepared by adding them to ceramics.

In order to improve the plasma resistance of the ceramic composite, it was attempted to improve the plasma resistance by coating the surface of the nano carbon having the excellent conductivity but the weak plasma resistance with MgO.

 1, Nano-carbon surface coated with oxide

In order to compensate the weak plasma properties of nano - carbon, MgO was selected from oxide ceramics excellent in plasma resistance and coated on the surface of nano - carbon.

The nano-carbon was peeled graphite (average particle diameter: 5 mu m, thickness: 20 to 50 nm) and oxidized graphene (thickness: 2 to 5 nm). The graphite was peeled off using a high shear mixer (6000 RPM, 1 hour). The graphite was mixed with graphite and sodium dodecylbenzenesulfonate (SDBS) as a dispersant to form a dispersion slurry, And then peeled off using a high shear mixer (shear mixer, 6000 rpm, 1 hour), filtered off after peeling, and dried to obtain peeled graphite.

(a) 70 g of a metal salt, MgCl _2, was added to 300 ml of an alcohol to prepare a metal salt solution.

(b) 30 g of nano-carbon and 108 ml of diethylamine as an amine compound were added to 100 ml of alcohol to prepare a nano-carbon slurry.

(c) The metal salt solution was added to the nano-carbon slurry and stirred for 24 hours to proceed the coating reaction. At this time, the alcohol soluble metal salt reacts with the hydroxyl group (OH -) generated by the acid-base reaction and is coated in the form of Mg (OH) ₂ . The mixing of diethylamine with the nanocarbon is performed by coating the surface of the nanocarbon with diethylamine to induce nucleation of Mg (OH) ₂ (coating) on the surface of the nanocarbon to form a coating through heterogeneous nucleation So that it will happen. When diethylamine is added after mixing the metal salt solution with the nanocarbon slurry, nucleation of Mg (OH) ₂ (coating agent) does not occur on the surface of the nanocarbon particle to be coated due to a rapid increase of pH, the nucleation of the Mg (OH) ₂ (coating agent) in the mixture of the slurry up, can be a Mg (OH) ₂ (coating) on the nano-carbon particle surface is grown in not coating solution as particles discard be coated .

(d) A nano-carbon slurry containing nano-carbon coated with Mg (OH) ₂ was dried in an oven at 80 to 120 캜 for about 12 hours. By drying, nano-carbon coated with Mg (OH) ₂ can be obtained.

(e) Upon completion of the drying, the nano-carbon coated with Mg (OH) ₂ was subjected to heat treatment in an oxidizing atmosphere at 350 to 400 ° C. Mg (OH) ₂ is not changed to MgO at a temperature lower than 350 ° C, and the nanocarbon is oxidized at a temperature higher than 400 ° C. MgO-coated nano-carbon can be obtained by the heat treatment.

2. Preparation of Al ₂ O ₃ - Nanocarbon Composites

In order to confirm the effect of plasma MgO coating, Al ₂ O ₃ - nano carbon composite using nano carbon which is not coated with MgO and Al ₂ O ₃ - nano carbon composite using MgO coated nano carbon were prepared. The manufacturing process is as follows, and the manufacturing process of the two composites is the same.

(a) Al MgO is used for the coating the nanocarbon ₂ O ₃ - for the production of nano-carbon composite material Al ₂ O ₃ 1948g, MgO is the coated nano-carbon 52g Al ₂ O ₃ balls are charged into the ball milling (ball milling machine to prepare a slurry having a solid content: water ratio of 5: 5. At this time, Cerasperse 5468CF as a dispersant was added in an amount of 1 wt% based on the solid content, and PVA (polyvinylalcohol) was added as a binder in an amount of 1.5 wt% relative to Al ₂ O _{3 to} prepare the slurry.

Using the nano-carbon is not coated with MgO Al ₂ O ₃ - with the Al ₂ O ₃ 1948g, nanocarbon 52g MgO is not coated to produce a nano-carbon composite material Al ₂ O ₃ balls are charged into the ball milling (ball milling machine ) To prepare a slurry having a solid content: water ratio of 5: 5. At this time, Cerasperse 5468CF as a dispersant was added in an amount of 1 wt% based on the solid content, and PVA (polyvinylalcohol) was added as a binder in an amount of 1.5 wt% relative to Al ₂ O _{3 to} prepare the slurry.

(b) Each of the thus-prepared slurries was granulated by using a spray dryer, and a hot air temperature of 180 ° C., an air temperature of 80 ° C., a disk rotation speed of 9000 rpm, and a slurry input amount of 0.5 L / min .

(c) Each of the granules was molded using a press. A metal mold of 50 × 50 mm size was used. After pressurizing at 1.0 ton / ㎠ for 10 seconds, the pressure was slowly removed for 10 seconds to complete press molding. In order to prevent CIP (Cold Isostatic Pressure) molding after press molding, the mold was packed in vacuum packing plastic to prevent flooding and vacuum packed. The packed compact was then subjected to a CIP process at a pressure of 1.8 ton / cm 2. The pressure schedule of the CIP process was maintained at 1.8 ton / ㎠ for 5 minutes, then decompressed to 0.2 ton / ㎠ and the pressure was slowly removed to normal pressure for 16 minutes.

(d) In addition to raw material powders such as Al ₂ O ₃ and nano-carbon, organic materials such as a dispersant and a binder are contained in the molded body, and a degreasing step for removing the organic additives is required. In the case of general oxide ceramics, the temperature is raised to about 600 ° C by adjusting the rate of temperature rise in the air, and air is injected into the electric furnace to burn and remove the organic additive. The Al ₂ O ₃ -nano carbon composite Argon (Ar) gas was injected into the vacuum furnace. The temperature was raised to 800 DEG C and maintained for 2 hours to remove the organic additive Respectively.

(e) The debinded molded body was sintered in a vacuum sintering furnace in which Ar gas was injected. The sintering temperature was in progress at the sintering temperature of the base merchant Al ₂ O _3, were heated to a sintering temperature of 1700 ℃ at a heating rate of 5 ℃ / min, it was carried out by sintering for 2 hours at the sintering temperature.

3. Evaluation of Al ₂ O ₃ - Nanocarbon Composites

(a) Nanocarbons coated with MgO (using nano-carbon graphene) are shown in FIGS. 3A and 3B by observing the microstructure using a transmission electron microscope (TEM).

Referring to FIGS. 3A and 3B, microstructure observation shows that the MgO particles enclose nano-carbon, which is seen as a plate.

FIG. 4 shows EDAX (Energy Dispersive X-ray Analysis) results of analyzing the components of MgO-coated nano-carbon (using graphite peeled off with nano-carbon).

Referring to FIG. 4, it can be seen from the EDAX results that MgO is distributed in the nano-carbon particles, which confirmed that the MgO particles were well coated on the nano-carbon.

(b) Table 4 below shows the result of measuring etch rate according to the presence or absence of coating of nano-carbon through plasma etching test.

Etch rate (cm / min) Etching time
(min) Complex using MgO-coated nano-carbon Composite using nanocarbon not coated with MgO 100 2.33 x 10 ^-6 6.56 x 10 ^-6 150 3.30 x 10 ^-6 6.22 x 10 ^-6

Plasma etch for 100 minutes under conditions of pressure 5 mTorr, RF-1 350 W, RF-2 100 W, CF ₄ 50 sccm, O ₂ 5 sccm, Ar 100 sccm for 100 minutes using an inductively coupled plasma (ICP) In the case of Al ₂ O ₃ - nano carbon composite using MgO - coated nano - carbon, the Al ₂ O ₃ - nano carbon composite using MgO - The etch rate was 2.8 times lower than that of As a result of the plasma etching test for 50 minutes, the etching rate of the Al ₂ O ₃ - nanocarbon composite using the nanocarbon coated with MgO was slightly increased. The MgO layer coated on the surface of the nanocarbon was very thin It is considered that the etching rate is slightly increased because the nano carbon is exposed by the etching of the MgO coating layer. The results of this etching rate show that the MgO coating improves the plasma resistance of the nanocarbon.

(c) After the plasma etching test, the microstructure of the Al ₂ O ₃ -nano-carbon composite was observed and shown in FIGS. 5 and 6. FIG. 5 shows the microstructure of Al ₂ O ₃ -nano-carbon composite using MgO-coated nano-carbon (using graphite peeled off with nano-carbon), and FIG. 6 shows nano-carbon (Using exfoliated graphite). The microstructure of Al ₂ O ₃ - nanocarbon composite is shown in Fig.

Referring to FIG. 5 and FIG. 6, as a result of observation of the microstructure, in the case of the Al ₂ O ₃ - nanocarbon composite using MgO-coated nanocarbon, nano carbon coated with MgO was observed after the plasma test It was confirmed that MgO protects the nano-carbon. 6, in the case of the Al ₂ O ₃ -nano-carbon composite using nano-carbon which is not coated with MgO, the surface of the composite has a pore formed by the preferential etching of the nano-carbon, It can be confirmed that the etching is accelerated mainly. The surface of the nano-carbon composite material Al ₂ O ₃ using a nano-carbon MgO is not coated - - Al ₂ O ₃ using the same MgO is coated nano-carbon and the etch rate results confirmed that the less the degree of etching than the nano-carbon composite I could. In the Al ₂ O ₃ - nanocarbon composite using nanocarbon without MgO coating, it was confirmed that the etching due to the increase of the specific surface area and the increase of the defect occurred by the preferential etching of the nano carbon.

(d) Table 5 below shows the results of 2-probe measurement of the electrical resistance of the Al ₂ O ₃ - nanocarbon composite.

Complex using MgO-coated nano-carbon Composite using nanocarbon not coated with MgO Electrical Resistance (Ωcm) 3.1 x 10 ⁴ 2.2 x 10 ⁴

As shown in Table 5, the electrical resistance of the Al ₂ O ₃ -nano-carbon composite using the nano-carbon coated with MgO was 3.1 × 10 ⁴ Ωcm, and the electrical resistance of the Al ₂ O _3- The nanocarbon composite showed an electrical resistance of 2.2 × 10 ⁴ Ωcm. These results show that there is little difference in electric resistance depending on the presence or absence of MgO coating. Thus, the MgO coating does not significantly affect the electrical resistance of the conductive ceramic composite.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, This is possible.

Claims (12)

delete delete delete delete (a) adding a metal salt comprising at least one metal selected from the group consisting of Mg and Zr to an alcohol to form a metal salt solution;
(b) adding a nanocarbon and an amine compound to the alcohol to form a nanocarbon slurry;
(c) mixing and reacting the metal salt solution and the nano-carbon slurry;
(d) coating the metal hydroxide on the surface of the nano-carbon while growing and growing nuclei of a metal hydroxide containing at least one metal selected from the group consisting of Mg and Zr on the surface of the nano-carbon by the reaction;
(e) drying the nanocarbon slurry containing the nanocarbon coated with the metal hydroxide to obtain a nanocarbon coated with the metal hydroxide;
(f) heat treating the nano-carbon coated with the metal hydroxide to convert the metal hydroxide into a metal oxide;
(g) mixing and molding the ceramic powder with the nano-carbon coated with the metal oxide; And
(h) sintering the molded product to obtain a ceramic-nano-carbon composite,
The metal salt including at least one metal selected from the group consisting of Mg and Zr includes at least one material selected from the group consisting of MgCl ₂ , MgNO ₃ , ZrCl _4, and Zr (NO ₃ ) ₂ ,
The amine compound includes methylamine, ethylamine, dimethylamine or diethylamine,
Wherein the metal hydroxide is Mg (OH) ₂ , Zr (OH) ₂ or a mixture thereof,
The nano-carbon is at least one carbon selected from the group consisting of graphene, graphene oxide and exfoliated graphite and has a thickness of 0.2 to 50 nm,
In the ceramic-nano-carbon composite, ceramic is a matrix,
Wherein the nanocarbon coated with the metal oxide is dispersed in the matrix,
The metal oxide includes one or more materials that are selected from the group consisting of MgO and ZrO _2,
Wherein the ceramic powder comprises at least one material selected from the group consisting of Al ₂ O ₃ , ZrO ₂ , AlN, SiC and Si ₃ N ₄ .
delete delete 6. The method of claim 5, wherein the alcohol is a mono-to pentavalent alcohol compound or a derivative thereof.
6. The method according to claim 5, wherein in step (c), the metal salt solution and the nano-carbon slurry are mixed so that the metal salt is 100 to 500 parts by weight based on 100 parts by weight of the nano- - Method for producing nano carbon composite.
6. The method of claim 5, wherein, in step (g), 0.1 to 15 parts by weight of the nano-carbon coated with the metal oxide is mixed with 100 parts by weight of the ceramic powder. &Lt; / RTI &gt;
[6] The method of claim 5, wherein the heat treatment is performed at a temperature of 350 to 400 [deg.] C.
6. The method according to claim 5, wherein the dispersant and the binder are further mixed in the step (g)
Preferably,
Raising the temperature of the binder to a first temperature of 600 to 900 占 폚 to pyrolyze the binder;
Maintaining said temperature at said first temperature;
Raising the temperature to a second temperature of 1600-1900 &lt; 0 &gt; C higher than the first temperature; And
And sintering while maintaining the first temperature at the second temperature. The method of manufacturing the plasma-conductive ceramic-nano-carbon composite according to claim 1,

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