WO2010056077A9 - High-hardness coating powder, and preparation method thereof - Google Patents

High-hardness coating powder, and preparation method thereof Download PDF

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Publication number
WO2010056077A9
WO2010056077A9 PCT/KR2009/006719 KR2009006719W WO2010056077A9 WO 2010056077 A9 WO2010056077 A9 WO 2010056077A9 KR 2009006719 W KR2009006719 W KR 2009006719W WO 2010056077 A9 WO2010056077 A9 WO 2010056077A9
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powder
salt
base
coating
producing
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PCT/KR2009/006719
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French (fr)
Korean (ko)
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WO2010056077A2 (en
WO2010056077A3 (en
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박희섭
류민호
엠 다우쉬왈리드
홍순형
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일진다이아몬드(주)
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Priority to KR10-2008-0113468 priority
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Publication of WO2010056077A2 publication Critical patent/WO2010056077A2/en
Publication of WO2010056077A3 publication Critical patent/WO2010056077A3/en
Publication of WO2010056077A9 publication Critical patent/WO2010056077A9/en

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    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09CTREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES; PREPARATION OF CARBON BLACK; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
    • C09C1/00Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/36Compounds of titanium
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00Physical properties of inorganic compounds
    • C01P2006/60Optical properties, e.g. expressed in CIELAB-values

Abstract

The present invention provides a method for preparing of high-hardness coating powder to easily coat the surface of a base with a coating material, said method comprising the steps of (a) dissolving a first chlorine (Cl)-based salt and a second fluorine (F)-based salt into a solvent to obtain a solution, (b) mixing a base, and a coating material containing titanium, with the solution, and drying the mixture, (c) putting the mixture obtained in said step (b) into a reaction furnace, and (d) heating the reaction furnace at a predetermined temperature, and keeping the reaction furnace at said predetermined temperature to cause a molten salt reaction wherein said first salt and said second salt are molten. The present invention also provides a high-hardness coating powder prepared by said method.

Description

High hardness coating powder and its manufacturing method

The present invention relates to a high hardness coating powder and a method for producing the same, and more particularly, to a method for easily coating a coating material on the surface of a base material and a powder produced by the method.

The cutting tool wears as the cutting process continues. The cutting tool is therefore formed using a hard material. Typically, a cutting tool is formed by mixing and sintering a base metal such as diamond and a metal.

The bonding force between the base metal and the metal is important for the durability of the cutting tool. In addition, since the sintering temperature is a high temperature, high temperature safety of the base material and prevention of oxidation of the base material surface are important.

To this end, techniques for forming a coating layer on the surface of the base material before mixing and sintering the base metal and metal have been studied. The surface of the base material can be coated to prevent oxidation, to improve the bonding strength with the metal, and to improve the high temperature safety.

However, when the particles of the base material are sub-micrometers, that is, fine particles of several nanometers to several micrometers, the base material agglomerates during the process of coating the coating material on the surface of the base material, and the coating material is unevenly coated on the surface of the base material, thereby coating the high hardness coating powder. There was a limit to getting.

This invention can provide the high hardness coating powder which can coat | cover a coating material on the surface of a base material, and its manufacturing method.

The present invention comprises the steps of (a) dissolving the first salt of chlorine (Cl) series, the second salt of fluorine (F) series in a solvent to form a solution, (b) a coating material containing a base material and titanium in the solution Mixing and drying, (c) placing the mixture obtained in step (b) into a reactor and (d) maintaining the reactor after heating to a predetermined temperature to melt the first salt and the second salt. Disclosed is a method for preparing a high hardness coating powder comprising the step of causing a molten salt reaction to occur.

In the present invention, the first salt may include at least two selected from the group consisting of KCl, NaCl, and BaCl 2.

In the present invention, the second salt may include at least one selected from the group consisting of NaF, K 2 TiF 6 and NaK 2 TiF 6 .

In the present invention, the solvent may include ethanol.

In the present invention, the step (d) may proceed at 800 ℃ to 1000 ℃.

In the present invention, the step (d) may proceed with the reaction while stirring the inside of the reactor in an Ar gas atmosphere.

In the present invention, the step (d) may be followed by the step of sonicating the powder obtained after the molten salt reaction in the reactor in distilled water and reacting with a hydrochloric acid solution.

In the present invention, after the step (d) may further comprise the step of removing the remaining coating material by a wet filling method.

In the present invention, after the step (d) may include the step of proceeding the crystallization by heat treatment in a hydrogen atmosphere.

In the present invention, the base material powder may include one selected from the group consisting of diamond, cubic boron nitride, and carbon nanotubes.

According to another aspect of the present invention there is disclosed a high hardness coating powder produced by the method of any one of the above methods.

The high hardness coating powder and the manufacturing method thereof according to the present invention can uniformly coat the coating material on the surface of the base material including the fine particles to obtain a high hardness coating powder having improved strength, improved surface properties and excellent high temperature safety.

1 is a flowchart sequentially illustrating a method for producing a high hardness coated powder of the present invention.

FIG. 2 is a diagram schematically illustrating an apparatus for describing the manufacturing method of FIG. 1 of FIG. 1.

3 is an enlarged view of a portion A of FIG. 1.

FIG. 4 is a photograph obtained by measuring an electron microscope of a powder formed according to a method of preparing a high hardness coating powder according to an embodiment of the present invention. FIG.

FIG. 5 is a diagram illustrating an X-ray diffraction pattern of the powder of FIG. 4.

FIG. 6 is a diagram of a powder formed according to a method for preparing high hardness coated powder according to another embodiment of the present invention, measured by an electron microscope. FIG.

FIG. 7 is a diagram illustrating an X-ray diffraction pattern of the powder of FIG. 6.

8 is a cross-sectional view of the powder of FIG. 6 using a focused ion beam (FIB).

9 is a cross-sectional view of the powder of FIG. 6 using a transmission electron microscope (TEM).

FIG. 10 is a diagram illustrating a measured component of part B of FIG. 9.

11 is a cross-sectional view of the powder of FIG. 6 after heat treatment using a transmission electron microscope.

FIG. 12 illustrates the limited field of view diffraction pattern of FIG. 11.

It is a figure for demonstrating the glass transition temperature of the powder of FIG.

14 is a view of a powder formed by a transmission electron microscope of a powder formed according to a method for producing a high hardness coated powder according to another embodiment of the present invention.

FIG. 15 is an enlarged view of C of FIG. 14.

FIG. 16 is a diagram illustrating a limited field of view diffraction pattern of the powder of FIG. 14.

<Brief description of symbols for the main parts of the drawings>

200: reactor 210: electric furnace

202: crucible 203: thermocouple

204: stirrer 205: gas inlet

206: gas outlet 310: molten salt

320: base material 330: covering material

Hereinafter, with reference to the embodiments of the present invention shown in the accompanying drawings will be described in detail the configuration and operation of the present invention.

1 is a flow chart sequentially showing a method for producing a high hardness coating powder of the present invention and FIG. 2 is a view schematically showing an apparatus for explaining the manufacturing method of FIG. 1 of FIG.

Referring to FIG. 1, in the method of preparing the high hardness coating powder according to the present embodiment, the first salt and the second salt are dissolved in a solvent to form a solution (101), and the base material and the coating material are mixed in a solution (102). ), Drying (103), placing the dried mixture into the reactor (104), heating and maintaining the reactor (105), removing residual salt (106), removing the residual coating material 107 and heat treating step 108.

Before the process proceeds, the members necessary for the manufacturing method according to the present embodiment are prepared.

The first salt is a chlorine-based salt and includes at least two selected from the group consisting of KCl, NaCl and BaCl 2. In the process of melting the salt as described below, two or more salts are selected to lower the melting temperature and ensure uniform distribution of the molten salt and high temperature safety. That is, the first salt may comprise two or more salts. That is, the first salt may be KCl and NaCl, NaCl and BaCl 2, and KCl and BaCl 2. The first salt may also be KCL and NaCl and BaCl 2.

The second salt comprises at least one selected from the group consisting of NaF, K 2 TiF 6 and NaK 2 TiF 6 .

The base material has particles of several micrometers or less and can be formed by using various materials. The base material includes any one selected from the group consisting of diamond, cubic boron nitride, and carbon nanotubes having excellent hardness.

First, for convenience of description, an embodiment of using diamond as a base material will be described.

 The coating includes titanium. Titanium is coated on the surface of the base material particles containing diamond to prevent oxidation of the surface of the base material particles, to ensure safety at high temperatures, and to improve the bonding force between the base powder and the metal powder in forming a cutting tool later. The coating can be prepared in various forms. That is, the coating material may be in the form of powder, foil, pellets. However, the coating material is preferably in the form of a powder so that uniform melting occurs easily in the reactor.

After preparing each material, first, the second salt is dissolved in a solvent to form a solution. At this time, the solvent may be ethanol. The base metal powder containing diamond is then added to the solution and the coating material containing titanium is added to the solution.

This mixed solution is then stirred to make it homogeneous and dried to form a mixed powder.

The particle size of the base metal powder containing diamond is several micrometers or less. Preferably they are 5 nanometers or more and 5 micrometers or less.

If the size of the particles of the base metal powder containing diamond is less than 5 nanometers, due to van der Waals' forces between the base material powder particles, dispersion between the base material powder particles is difficult and aggregation occurs, and the base material powder particles are coated with the coating material. There is a limit. Therefore, the particle size of the base metal powder containing diamond is preferably 5 nanometers or more.

In addition, when the particle size of the base metal powder containing diamond exceeds 5 micrometers, the toughness of the cutting tool is reduced when forming the cutting tool using the base material. Therefore, the particle size of the base metal powder containing diamond is preferably 5 micrometers or less.

Since the particle size of the base material powder is small, the base material particles agglomerate with each other by van der Waals' force in the process of coating the surface of the base material particles with a coating material.

However, in this embodiment, first, the second salt, the base material and the coating material are dissolved by using ethanol to form a solution. This facilitates the dispersion of each particle. In particular, a uniform dispersion of each particle occurs during the process of forming the solution and then stirring it evenly. And it is possible to remove unnecessary solvent components through drying to form a mixed powder of the first salt, the second salt, the base material and the coating material in a uniform state.

Then, a process of melting the mixed powder is performed. 2 schematically illustrates a reactor in which mixed powder is added and a process is performed.

The reactor 200 includes an electric furnace 201, a crucible 202, a thermocouple 203, an agitator 204, a gas inlet 204, and a gas outlet 205. The mixed powder described above is placed in the crucible 202. The mixed powder in the crucible 202 may be melted by supplying heat from the electric furnace 201 surrounding the crucible 202. The electric furnace 201 is a method of supplying heat using electric energy. However, the present invention is not limited thereto, and various types of heat sources may be used as long as the heat necessary for melting the mixed powder of the crucible 202 can be supplied.

The thermocouple 203 may be used to measure the temperature in the process of melting and stirring the mixed powder and to adjust the heat supply amount of the electric furnace 201 for supplying heat to the crucible 202. The mixed powder is melted so that the reaction of melting the first salt and the second salt occurs at 800 ° C to 1000 ° C.

The melting temperature of a 1st salt, a 2nd salt is about 600 degreeC or more. In addition, the reaction rate due to diffusion of titanium atoms when the coating material containing titanium is melted is proportional to the temperature. In the melting temperature atmosphere below 800 ° C, the reaction rate due to diffusion of titanium atoms is reduced, and the uniformity of the coating layer formed after the coating material is coated on the base material is reduced. Therefore, the reaction in which the mixed powder is melted to melt the first salt and the second salt is controlled to occur at 800 ° C. or higher.

In addition, durability is weakened by brittleness of a base material in the atmosphere of temperature exceeding 1000 degreeC. Therefore, the reaction in which the mixed powder is melted to melt the first salt and the second salt is controlled to occur at 1000 ° C. or lower.

The stirrer 204 allows the first salt, the second salt, the base material and the coating material to be evenly stirred when the mixed powder is melted. The stirrer 204 preferably has the form of an impeller.

Argon (Ar) gas is introduced and discharged through the gas inlet 205 and the gas outlet 206. Through this, the melting reaction of the mixed powder in the crucible may proceed in an inert atmosphere.

3 is an enlarged view of A of FIG. 2. Referring to FIG. 3, the base material 320 and the coating material 330 are evenly distributed in the molten salt 310 in which the first salt and the second salt are melted.

In the crucible 202, the mixed powder is melted and maintained for a period of time, and the coating material is oxidized and reduced in a molten salt to coat the coating material on the surface of the base material. Specifically, the following reactions occur sequentially.

(1) Ti-> 2Ti 2+

(2) 2Ti 2+ -> Ti + Ti 4+

(3) C (diamond) + Ti-> TiC

First, the coating material is melted in the molten salt in which the first salt and the second salt are molten to cause a reaction in the above reaction (1). Particularly, when K 2 TiF 6 or NaK 2 TiF 6 is used as the second salt, the reaction of Ti + Ti 4+ -> 2Ti 2 occurs in the molten salt because the second salt forms tetravalent titanium ions.

(2) reaction occurs in the above reaction on the surface of the base metal powder. That is, titanium divalent ions formed in the molten salt are reduced on the surface of the base material. The produced titanium tetravalent ions again promote the oxidation of titanium in the molten salt.

Then, reaction of (3) occurs on the surface of the base material. That is, diamond and titanium react at a high temperature on the surface of the particles of the base metal including diamond to form titanium carbide. That is, the coating powder which coat | covered the coating material is formed on the surface of a base material.

The coated powder recovered from the crucible 202 is in a lump state immediately after the high temperature melting process is finished. In addition, since the remaining salts and coating materials aggregate together with the coating powder without reacting with the base metal in the melting process, a process of separating these is necessary.

First, in order to remove the remaining salt, the coating powder, the remaining salt and the powder containing the remaining coating material are put in distilled water and stirred. Ultrasonication is then performed to remove any remaining salt. At this time, after the sonication, a hydrochloric acid solution may be added to proceed the process quickly and easily.

After removing the remaining salt, it is not reacted with the base material to remove the remaining coating material. The remaining coating material powder can be easily removed through the wet coloring. In other words, the remaining titanium powder and the coating powder are agglomerated in a liquid such as distilled water to fill the liquid powder to remove the remaining titanium powder.

Then use a centrifuge to remove the solution used for wet filling. Distilled water can then be added to dissolve and remove traces of the remaining salt.

The coated powder is then recovered by vacuum filtering. That is, the diamond powder coated with titanium is recovered.

The recovered coating powder is heat-treated after drying in a vacuum atmosphere. The heat treatment is performed in a hydrogen atmosphere at a temperature of 800 ° C. or higher. Through this, titanium carbide formed on the surface of the base material is crystallized, and adhesion between the base material and the coating material is improved and durability is improved.

FIG. 4 is a photograph obtained by measuring an electron microscope of a powder formed according to a method of preparing a high hardness coated powder according to an embodiment of the present invention, and FIG. 5 is an X-ray diffraction pattern of the powder of FIG. 4. Drawing.

Specifically, KCl, NaCl and BaCl 2 were used as the first salt, and NaF and NaK 2 TiF 6 were used as the second salt. KCl, NaCl and BaCl 2 were each prepared with 10 g, and 10 g of NaF and 5 g of NaK 2 TiF 6 were prepared. The base material contains diamond, and the diamond particles have a size of 1.5 micrometers or less. The coating material was prepared 2g of titanium in powder form and the titanium powder was to have a particle size of 100mesh.

4 (a) is a diamond powder before using the manufacturing method according to the present embodiment, Figure 4 (b) is a diamond powder coated with a coating material by the manufacturing method according to the present embodiment, Figure 4 (c) Is a scanning electron microscope (SEM) photograph which shows enlarged FIG. 4 (b).

Comparing Fig. 4 (a) with Fig. 4 (b) and Fig. 4 (c) it can be seen that the coating material is coated on the surface of each particle of the base material powder containing diamond. 5, these components can be easily identified. Fig. 5 (a) shows the diamond powder before coating by the manufacturing method according to the present embodiment, and Fig. 5 (b) shows the diamond powder after coating with the manufacturing method according to the present embodiment. The peaks indicated by the inverted triangle are present in both (a) and (b) of FIG. 5, indicating the diamond component. However, the peaks indicated by circles are present only in Fig. 5 (b), which indicates titanium carbide. Through this, it can be seen that titanium was evenly coated on the surface of the fine diamond particles by the manufacturing method according to the present embodiment.

FIG. 6 is a diagram illustrating a powder formed according to a method of preparing a high hardness coated powder according to another embodiment of the present invention with an electron microscope, and FIG. 7 is a diagram illustrating an X-ray diffraction pattern of the powder of FIG. 6.

For convenience of explanation, the following description will focus on differences from the above-described embodiment. This embodiment has a difference in that the base material using cubic boron nitride rather than diamond as compared with the above-described embodiment.

As in the above embodiment, first and second salts are dissolved in a solvent to form a solution. At this time, the solvent may be ethanol. Then, the base metal powder containing cubic boron nitride is put into the solution, and the coating material containing titanium is put into the solution. This mixed solution is then stirred to make it homogeneous and dried to form a mixed powder.

The particle size of the base metal powder containing cubic boron nitride is several micrometers or less. Preferably they are 50 nanometers or more and 5 micrometers or less.

If the size of the particles of the base material powder containing cubic boron nitride is less than 50 nanometers, it is difficult to disperse due to van der Waals' forces between the cubic boron nitride particles and aggregation occurs, so that there is a limit to coating the coating material on the base material powder particles. have. Therefore, the particle size of the base metal powder containing cubic boron nitride is preferably 50 nanometers or more.

In addition, when the size of the particles of the base metal powder containing boron cubic boron exceeds 5 micrometers, the toughness of the cutting tool is reduced when forming the cutting tool using the base material. Therefore, the particle size of the base metal powder containing cubic boron nitride is preferably 5 micrometers or less.

In the crucible 202, the mixed powder is melted and maintained for a period of time, so that the coating material is oxidized and reduced in the molten salt so that the coating material is coated on the surface of the base material. Specifically, the following reactions occur.

(1) Ti-> 2Ti 2+

(2) 2Ti 2+ -> Ti + Ti 4+

(3) 3Ti + 2BN-> TiB 2 + 2TiN

First, the coating material is melted in the molten salt in which the first salt and the second salt are molten to cause a reaction in the above reaction (1). Particularly, when K 2 TiF 6 or NaK 2 TiF 6 is used as the second salt, the reaction of Ti + Ti 4+ -> 2Ti 2 occurs in the molten salt because the second salt forms tetravalent titanium ions.

(2) reaction occurs in the above reaction on the surface of the base metal powder. That is, titanium divalent ions formed in the molten salt are reduced on the surface of the base material.

Then, reaction of (3) occurs on the surface of the base material. That is, boron and titanium, nitrogen and titanium react at a high temperature on the surface of the base material particles containing cubic boron nitride to form titanium boride and titanium nitride.

Subsequently, subsequent steps such as residual salt removal, residual coating material removal, and heat treatment are performed to obtain a high hardness coating powder having a coating material coated on the surface of the base material. Details of subsequent processes are the same as in the above-described embodiment and thus will be omitted.

6 (a) is a cubic boron nitride powder before using the manufacturing method according to the present embodiment, Figure 6 (b) is a cubic boron nitride powder coated with a coating material in the manufacturing method according to the present embodiment, Fig. 6 (c) is a scanning electron microscope (SEM) photograph showing an enlarged view of FIG. 6 (b).

Comparing FIG. 6 (a), FIG. 6 (b) and FIG. 6 (c), it can be seen that the coating material is coated on the surfaces of the particles of the base metal powder containing cubic boron nitride. Referring to FIG. 7, these components can be easily identified. (A) of FIG. 7 shows a cubic boron nitride powder before coating by the manufacturing method which concerns on a present Example, FIG. 7 (b) shows the cubic boron nitride powder after coating by a manufacturing method which concerns on a present Example. will be. The peaks indicated by the inverted triangle are present in both (a) and (b) of FIG. 7, indicating a cubic boron nitride component. However, the peaks indicated by circles are present only in FIG. 7B, which indicates titanium nitride. Through this, it can be seen that titanium was evenly coated on the surface of the fine cubic boron nitride particles by the manufacturing method according to the present embodiment.

8 is a cross-sectional view of the powder of FIG. 6 using a focused ion beam (FIB).

Referring to FIG. 8, it can be seen that a coating layer containing titanium formed on the surface of the cubic boron nitride is uniformly formed. In FIG. 8, a part indicated by a) is a layer for protecting the surface of the sample from the focused ion beam FIB with a protective layer formed of platinum Pt for experiment. In Figure 8 b) is the coating layer and in Figure 8 c) is the base material. Referring to FIG. 8, the coating layer has a thickness of 200 nm.

FIG. 9 is a diagram illustrating a cross section of the powder of FIG. 6 using a transmission electron microscope (TEM), and FIG. 10 is a diagram illustrating a component of part B of FIG. 9.

In FIG. 9, (a) shows a base material part, (c) shows a covering layer part, and (b) shows the boundary of a base material and a covering layer. It is a graph which shows the component analysis result of each part. In FIG. 10, (a) is boron, (b) is nitrogen, (c) is oxygen, and (d) is titanium.

Referring to Figure 10 (a) since the base material includes a cubic boron nitride, nitrogen, boron is the main component. At the boundary (b), titanium as a coating material increases, and titanium is most present at the coating layer (c). Through this, it can be seen that the coating material containing titanium was stably coated on the surface of the particles of the base material containing cubic boron nitride.

11 is a cross-sectional view of the powder of FIG. 6 after heat treatment using a transmission electron microscope, and FIG. 12 is a view illustrating the limited field diffraction pattern of FIG. 11. In Fig. 11, a) indicates the base material and b) indicates the coating layer. Referring to FIGS. 11 and 12, the titanium containing coating layer has a polycrystalline structure composed of crystals having a size of several tens of nanometers or less.

It is a figure for demonstrating the glass transition temperature of the powder of FIG. Specifically, the left Y-axis coordinate of FIG. 13 indicates that the heat flux is measured by differential scanning calorimetry (DSC), and shows that the heat flux decreases as the temperature increases, and the right Y-axis of FIG. The coordinates are values obtained by differentiating the heat flow rate value of the left Y coordinate, and change in value according to a minute temperature change. Referring to Figure 13, the glass transition temperature is about 950 ℃. This means that the coating layer containing titanium on the cubic boron nitride surface was crystallized at around 950 ° C in an amorphous state. The present invention can easily form a coating layer crystallized as described above by heat-treating the coated base material powder in a hydrogen atmosphere.

FIG. 14 is a view of a powder formed according to a method of preparing a high hardness coated powder according to another embodiment of the present invention with a transmission electron microscope, and FIG. 15 is an enlarged view of C of FIG. 14. FIG. 16 is a diagram illustrating a limited field of view diffraction pattern of the powder of FIG. 14.

For convenience of explanation, the following description will focus on differences from the above-described embodiment. This embodiment has a difference in that the base material using carbon nanotubes other than diamond or cubic boron nitride as compared with the above-described embodiment.

As in the above embodiment, first and second salts are dissolved in a solvent to form a solution. At this time, the solvent may be ethanol. The base material containing the carbon nanotubes is then added to the solution and the coating material containing titanium is added to the solution. This mixed solution is then stirred to make it homogeneous and dried to form a mixed powder.

The particle size of the base metal powder containing the carbon nanotubes is several micrometers or less. Preferably they are 5 nanometers or more and 50 nanometers or less.

If the particle size of the base metal powder containing carbon nanotubes is less than 5 nanometers, the base metal powder particles are not dispersed well due to van der Waals' forces between the respective base metal powder particles, and aggregation occurs between the particles. There is a limit to coating the coating material. Therefore, the particle size of the base metal powder containing diamond is preferably 5 nanometers or more.

In addition, when the size of the particles of the base metal powder containing the carbon nanotube exceeds 50 nanometers, the toughness of the cutting tool is reduced when forming the cutting tool using the base material. Therefore, the particle size of the base metal powder containing the carbon nanotubes is preferably 5 micrometers or less.

In the crucible 202, the mixed powder is melted and maintained for a period of time so that the coating material undergoes oxidation and reduction reactions in the molten salt so that the coating material is coated on the surface of the base material. Specifically, the following reactions occur.

(1) Ti-> 2Ti 2+

(2) 2Ti 2+ -> Ti + Ti 4+

(3) Ti + C (carbon nanotube)-> TiC

First, the coating material is melted in the molten salt in which the first salt and the second salt are molten to cause a reaction in the above reaction (1). Particularly, when K 2 TiF 6 or NaK 2 TiF 6 is used as the second salt, the reaction of Ti + Ti 4+ -> 2Ti 2 occurs in the molten salt because the second salt forms tetravalent titanium ions.

(2) reaction occurs in the above reaction on the surface of the base metal powder. That is, titanium divalent ions formed in the molten salt are reduced on the surface of the base material.

Then, reaction of (3) occurs on the surface of the base material. That is, carbon and titanium react at a high temperature on the surface of the particles of the base metal including the carbon nanotubes to form titanium carbide.

Subsequently, subsequent steps such as residual salt removal, residual coating material removal, and heat treatment are performed to obtain a high hardness coating powder having a coating material coated on the surface of the base material. Details of subsequent processes are the same as in the above-described embodiment and thus will be omitted.

14 and 15, it can be seen that a coating layer is formed on the surface of the carbon nanotube as the base material. In addition, it can be seen from FIG. 16 that the titanium-containing coating material is coated on the surface of the carbon nanotube to form titanium carbide in the coating layer.

Through this, it can be seen that titanium was evenly coated on the surface of the fine cubic boron nitride particles by the manufacturing method according to the present embodiment.

 Although described with reference to the embodiment shown in the drawings it is merely exemplary, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Carbon nanotubes have been studied for use in cutting tools as materials having high strength, high modulus of elasticity, high conductivity, and high thermal conductivity. However, when carbon nanotubes are used as the base material, evenly dispersed and bonding strength at the interface with the coating material is a problem.

In this embodiment, the coating material containing titanium can be uniformly coat | covered on the surface of the base material containing a carbon nanotube. Through this, it is possible to easily form a high hardness coating powder with improved hardness and surface properties.

Claims (14)

  1. (a) dissolving a first salt of chlorine (Cl) series and a second salt of fluorine (F) series in a solvent to form a solution;
    (b) mixing and drying the base material and a coating material containing titanium in the solution;
    (c) placing the mixture obtained in step (b) into a reactor; And
    (d) a method of producing a high hardness coating powder comprising heating and maintaining the reactor at a predetermined temperature to cause a molten salt reaction in which the first salt and the second salt are melted.
  2. According to claim 1,
    Wherein said first salt comprises at least two selected from the group consisting of KCl, NaCl and BaCl 2.
  3. According to claim 1,
    Wherein said second salt comprises at least one selected from the group consisting of NaF, K 2 TiF 6 and NaK 2 TiF 6 .
  4. According to claim 1,
    The solvent is a method for producing a high hardness coating powder comprising ethanol;
  5. According to claim 1,
    Step (d) is a method for producing a high hardness coating powder proceeds from 800 ℃ to 1000 ℃.
  6. According to claim 1,
    Step (d) is a method for producing a high hardness coating powder to proceed with the reaction while stirring the inside of the reactor in an Ar gas atmosphere.
  7. The method of claim 1
    Performing the step (d) and then putting the powder obtained after the molten salt reaction in the reactor into distilled water and performing ultrasonic treatment; And
    A method of producing a high hardness coating powder comprising the step of reacting with a hydrochloric acid solution.
  8. The method of claim 1
    Removing the coating material remaining by the wet filling method after the step (d) further comprising the method of producing a hard coating powder.
  9. The method of claim 1
    After the step (d) and the heat treatment in a hydrogen atmosphere comprising the step of proceeding the crystallization method of producing a high hardness coating powder.
  10. The method of claim 1
    The base material powder is a method for producing a high hardness coating powder comprising a freezing one selected from the group consisting of diamond, cubic boron nitride and carbon nanotubes.
  11. The method of claim 1
    The base material powder is a method for producing a high hardness coating powder comprising diamond particles having a size of 5 nanometers to 5 micrometers.
  12. The method of claim 1
    The base material powder is a method for producing a high hardness coating powder comprising cubic boron nitride particles having a size of 50 nanometers to 5 micrometers.
  13. The method of claim 1
    The base material powder is a method of producing a high hardness coating powder comprising carbon nanotube particles having a size of 5 nanometers to 50 nanometers.
  14. The high hardness coating powder manufactured by the manufacturing method of any one of Claims 1-13.
PCT/KR2009/006719 2008-11-14 2009-11-16 High-hardness coating powder, and preparation method thereof WO2010056077A2 (en)

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