KR20170055235A - Synthesis Method of cBN thin film - Google Patents

Abstract

The present invention relates to a method to synthesize a cubic BN (cBN) thin film. According to the present invention, disclosed is a method to manufacture a graft type photosensitive hydration gel, comprising: a first step of using diamond to form a nuclei on a substrate; a second step of using physical vapor deposition to deposit a BN thin film on the substrate; and a third step of thermally treating the substrate on which the BN thin film is deposited. According to the present invention, a crystallinity of the cBN is excellent and a crystalline density is high. Since a cBN thin film is deposited, characteristics of wear resistance material such as cutting and molding tool, etc., are able to be improved irrespective of a shape of a tool.

Description

(Synthesis Method of cBN thin film)

The present invention relates to a method of synthesizing a cubic boron nitride (cBN) thin film, and more particularly, to a method of depositing a cubic boron nitride thin film which can be used for improving abrasion resistance by coating a wear- .

Currently, cutting tool, mold or precision element mechanical parts are required to be improved in precision, performance and durability, and as the use environment becomes harsh, the surface properties of these parts are required to be improved. As a result, new thin- Demand is increasing gradually. Cutting tools are usually coated with WC-Co carbide tool or metal hardened tool with high hardness thin film material. For example, a metal nitride system such as TiAlN, which is a thin film material used for coating, has a maximum hardness of 30 GPa. However, such a hardness value has a problem in the cutting process of the currently developed material, and it is required to develop a new thin film material having a hardness of 50 GPa or more.

cBN (cubic boron nitride) is a diamond that has high hardness, thermal stability and high thermal conductivity after diamond. It is chemically stable against iron metal unlike diamonds, Processing tools, wear-resistant coating materials. In general, boron nitride (BN) has cubic and hexagonal structures. At room temperature and pressure, the hexagonal structure is stable. Therefore, cBN is a material that does not exist in the natural world and is synthesized artificially under high-temperature and high-pressure thermodynamic conditions.

For example, International Publication No. 2012/053375 (Patent Document 1) discloses a composition of a cBN sintered body capable of cutting a dough tile cast iron to a long life. That is, in Patent Document 1, a carbonitride of any one of Hf, TiHf, Group IVa element, Va group element and Group VIa element (excluding Ti) in the periodic table is added to the main component constituting the bonding phase of the cBN sintered body , The life span of the cBN sintered body is increased. However, the method of forming cBN by the sintering method as described above has a problem in that it is difficult to sinter a tool having a spiral shape like an end mill because of a method of attaching powder to the tool.

As a result of this problem, a method of depositing a cBN thin film by a physical vapor deposition method like a sputtering method has been studied (K Yamamoto and M Keunecke and K Bewilogue, Deposition of well adhering cBN films up to 2 μm thickness by BCN gradient layer system , 2.1preparation, 332page, 2000). However, according to this physical vapor deposition method, it is necessary to apply high energy to make the first nucleus.

WO2012053375 A1

K Yamamoto and M Keunecke and K Bewilogue, Deposition of well adhering cBN films up to 2 占 퐉 thickness by B-C-N gradient layer system, 2.1preparation, 332page, 2000)

A problem to be solved by the present invention is to provide a cubic boron nitride thin film which can be used as a wear resistant coating material by forming a large number of crystal structures irrespective of the shape of a tool.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a method of depositing a cubic boron nitride thin film, comprising: a first step of forming nuclei on a substrate using diamond; A second step of depositing a thin film of boron nitride (hBN) on the substrate using a physical vapor deposition process; And a third step of heat-treating the substrate on which the boron nitride thin film is deposited.

Also, preferably, the physical vapor deposition process may be performed by sputtering.

Also preferably, the physical vapor deposition process can be performed at 550 ° C to 650 ° C.

Also preferably, the physical vapor deposition process can be carried out for 4 hours or more.

Also, preferably, the third step may be heat-treated in an argon (Ar) atmosphere.

Also, preferably, the heat treatment temperature in the third step may be 1300 ° C to 1400 ° C.

Also, preferably, the heat treatment time in the third step may be 1.5 to 2.5 hours.

Another embodiment of the present invention for solving the problem provides a cutting tool in which a cubic boron nitride thin film is deposited by the above method.

According to the deposition method of the present invention, the crystallinity of the cubic boron nitride is remarkable, the crystal density is high, and the cubic boron nitride thin film is deposited by the deposition method of the present invention. Therefore, It is possible to improve the abrasion resistance of the wear resistant parts.

Fig. 1 shows XRD peaks of the respective boron nitride thin films obtained in Example 1 and Comparative Example 2. Fig.
2 is a SEM image of each of the boron nitride thin films obtained in Example 1, Comparative Examples 2 and 3. FIG.
3 is an SEM image of each of the boron nitride thin films obtained in Example 2, Comparative Examples 4, 5, and 6.
4 is an SEM image of the boron nitride thin films obtained in Comparative Examples 7 and 8.
5 shows an SEM image of the boron nitride thin film obtained in Comparative Example 9. Fig.
Fig. 6 shows SEM images of the boron nitride thin films obtained in Comparative Examples 10 and 11. Fig.

Hereinafter, the present invention will be described more specifically.

The cubic boron nitride thin film according to the present invention comprises: a first step of forming nuclei on a substrate using diamond; A second step of depositing a boron nitride (hBN) thin film on a substrate using a physical vapor deposition process; And a third step of heat-treating the substrate on which the boron nitride thin film is deposited.

In the present invention, the physical vapor deposition process in the second step may be performed by sputtering. The method of depositing the cubic boron nitride thin film by the physical vapor deposition process is advantageous in that the cubic boron nitride thin film can be deposited regardless of the shape of the tool compared to the method of forming the cubic boron nitride thin film by the sintering method have.

Also, in the present invention, the physical vapor deposition process may be performed at 550 ° C to 650 ° C. Although the RF or DC power of a typical physical vapor deposition process is 700 ° C to 800 ° C, the physical vapor deposition process according to the present invention can be carried out at 550 ° C to 650 ° C, preferably since it involves a heat treatment step in a gas atmosphere . Most preferably, the physical vapor deposition process may be performed at 600 < 0 > C.

Further, the physical vapor deposition process may be performed for 4 hours or more. Most preferably, the physical vapor deposition process can be carried out for 4 hours.

In the present invention, the third step may be heat-treated in an argon gas atmosphere.

In addition, the heat treatment temperature in the third step may be 1300 ° C to 1450 ° C. Most preferably, the heat treatment temperature in the third step may be 1400 ° C.

In addition, the heat treatment time in the third step may be 1.5 to 2.5 hours. Most preferably, the heat treatment in the third step can be performed for 2 hours.

The cubic boron nitride thin film deposited according to the present invention is characterized in that the crystallinity of the cubic boron nitride is remarkable and the density of the crystal is high.

Another embodiment of the present invention can provide a cutting tool in which a cubic boron nitride thin film is deposited by the above method. The cutting tool on which the cubic boron nitride thin film is deposited has a uniform thin film and can be deposited irrespective of the shape of the tool and has excellent wear resistance.

Hereinafter, the present invention will be described in more detail with reference to Examples.

It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments in accordance with the gist of the present invention .

Before and after heat treatment Boron nitride  Deposition of thin films

< Example  1>

The Si substrate and the bulk diamond were put together and polished for 1 hour using an ultrasonic cleaner to scratch the surface of the Si substrate. In order to remove impurities on the surface, acetone and distilled water were subjected to primary and secondary cleaning for 10 minutes, respectively.

An RF power of 150 W was connected to the prepared Si substrate by sputtering, and a boron nitride thin film was deposited at 600 ° C. for 4 hours under an atmosphere of Ar 25 sccm and N 2 10 sccm. As the sputtering target of the boron nitride thin film, an hBN target having a purity of 99.9% was used.

The Si substrate on which the boron nitride thin film was deposited was heat-treated at 1400 캜 for 2 hours in an Ar gas atmosphere to deposit a cBN thin film.

< Comparative Example  1>

The Si substrate and the bulk diamond were put together and polished for 1 hour using an ultrasonic cleaner to scratch the surface of the Si substrate. In order to remove impurities on the surface, acetone and distilled water were subjected to primary and secondary cleaning for 10 minutes, respectively.

An RF power of 150 W was connected to the prepared Si substrate by sputtering, and a boron nitride thin film was deposited at 600 ° C. for 4 hours under an atmosphere of Ar 25 sccm and N 2 10 sccm. A thin film of nitride was deposited using a boron nitride thin film as a sputtering target with an hBN target having a purity of 99.9%.

The XRD peaks of the respective boron nitride thin films obtained in Example 1 and Comparative Example 1 were measured and shown in FIG.

1, the peak of cBN does not appear in the XRD (FIG. 1 (a)) of Comparative Example 1, which is not subjected to the heat treatment after the sputtering process. However, in the XRD of Example 1 (FIG. peaks were observed, indicating that cBN was generated.

Sputtering  Temperature( Example  1 and Comparative Example  2, 3) to  Following Boron nitride  Deposition of thin films

< Comparative Example  2 and 3>

The boron nitride thin film was deposited by the same procedure as in Example 1 except that the sputtering temperature was 500 ° C for Comparative Example 2 and the sputtering temperature was 700 ° C for Comparative Example 3. [

An SEM image of each of the boron nitride thin films obtained in Example 1 and Comparative Examples 2 and 3 is shown in Fig.

Referring to FIG. 2, the SEM image of the surface of Comparative Example 2 (FIG. 2 (a)) after the sputtering deposition at 500 ° C. shows a large amount of amorphous boron nitride. ) Of sputtering at 600 ° C. The SEM image of the surface after heat treatment showed that most of the surface was crystalline boron nitride. The SEM image of the surface of Comparative Example 3 (FIG. 2 (c)) after heat treatment after sputtering deposition at 700 ° C shows that it is a round shaped boron nitride which can not be seen as a crystal.

Sputtering  Over time Boron nitride  Deposition of thin films

< Example  2>

The boron nitride thin film of Example 2 was deposited by the same procedure as in Example 1 except that the sputtering process was performed for 5 hours.

< Comparative Example  4, 5, 6>

The boron nitride thin films of Comparative Examples 4, 5, and 6 were deposited by sputtering for 30 minutes, 1 hour, and 3 hours, respectively.

SEM images of the respective boron nitride thin films obtained in Example 2 and Comparative Examples 4, 5 and 6 are shown in FIG.

Referring to FIG. 3, SEM images of the surfaces of Comparative Examples 4, 5 and 6 (FIGS. 3A, 3B, and 3C) after the sputtering deposition for 30 minutes, 1 hour, SEM image of the surface after heat treatment after sputtering deposition for 4 hours and 5 hours in Example 1 (FIG. 2B) and Example 2 (FIG. 3D) It can be seen that it is crystalline boron nitride.

Depending on the type of heat treatment gas atmosphere Boron nitride  Deposition of thin films

< Comparative Example  7, 8>

The boron nitride thin film was deposited by the same procedure as in Example 1 except that the heat treatment was performed in an N 2 atmosphere in Comparative Example 7 and the heat treatment was performed in air in Comparative Example 8.

SEM images of the boron nitride thin films obtained in Comparative Examples 7 and 8 are shown in FIG.

Referring to FIG. 4, the SEM image of the surface of Comparative Example 7 (FIG. 4 (a)) subjected to the heat treatment under the N2 atmosphere shows a large amount of amorphous boron nitride. In Comparative Example 8 (FIG. SEM image of the surface of the heat-treated surface in FIG. 2 (a) shows that the crystal is an army arm but the density of crystals is low. However, when the SEM image of the surface heat treated in the Ar atmosphere of Example 1 .

Depending on the heat treatment temperature Boron nitride  Deposition of thin films

< Comparative Example  9>

The boron nitride thin film of Comparative Example 8 was deposited by performing the same process as that of Example 1 and performing the heat treatment at 1200 ° C.

An SEM image of the boron nitride thin film obtained in Comparative Example 9 is shown in Fig.

5, the SEM image of the surface heat treated at 1200 ° C of Comparative Example 9 (FIG. 5) shows a large amount of boron nitride in an amorphous state. However, in the case of Example 1 (FIG. 2 (b) SEM images of one surface reveal that most are crystalline boron nitride.

Depending on the heat treatment time Boron nitride  Deposition of thin films

< Comparative Example  10, 11>

A boron nitride thin film was deposited by the same procedure as in Example 1 except that the heat treatment was performed for 1 hour in Comparative Example 7 and the heat treatment was performed in 3 hours in Comparative Example 8. [

SEM images of the boron nitride thin films obtained in Comparative Examples 10 and 11 are shown in FIG.

6, the SEM image of the surface of Comparative Example 10 (FIG. 6 (a)) subjected to heat treatment for 1 hour shows that the density of cubic boron nitride is low and is not crystallized, )), The SEM image of the surface heat treated for 3 hours shows that the cubic boron nitride is not conspicuous and the surface is slightly rough, but the SEM image of the surface heat treated for 2 hours in Example 1 (Fig. 2 (b) It can be seen that most of them are crystalline boron nitride.

Claims (8)

A first step of forming nuclei on the substrate using diamond;
A second step of depositing a thin film of boron nitride (hBN) on the substrate using a physical vapor deposition process; And
A third step of heat-treating the substrate on which the boron nitride thin film is deposited;
Wherein the boron nitride thin film is deposited on the substrate.
The method according to claim 1,
Wherein the physical vapor deposition process is performed by sputtering. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
The method according to claim 1,
Wherein the physical vapor deposition process is performed at a temperature in the range of 550 to 650 占 폚.
The method according to claim 1,
Wherein the physical vapor deposition process is performed for at least 4 hours. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
The method according to claim 1,
Wherein the third step is a heat treatment in an argon (Ar) atmosphere.
The method according to claim 1,
Wherein the annealing temperature in the third step is in the range of 1300 DEG C to 1400 DEG C. 9. A method for depositing a cubic boron nitride thin film,
The method according to claim 1,
Wherein the annealing time in the third step is from 1.5 to 2.5 hours.
A cutting tool in which a cubic boron nitride thin film is deposited by the method of any one of claims 1 to 6.

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