KR100347422B1 - WC-TiN SUPERLATTICE COATING LAYER, APPARATUS AND METHOD FOR FABRICATING THE SAME - Google Patents

Abstract

The present invention discloses a superhard coating film and its manufacturing apparatus and method. The superhard coating film of the present invention disclosed is a base material; At least one layer formed on the base material includes a super lattice wear resistant layer, wherein the super lattice wear resistant layer is characterized in that the TiN layer and the WC layer are alternately laminated at least one or more times.

Description

Tungsten Carbide-Titanium Nitride Superlattice Coating Film and Its Manufacturing Apparatus and Method {WC-TiN SUPERLATTICE COATING LAYER, APPARATUS AND METHOD FOR FABRICATING THE SAME}

The present invention relates to a superlattice coating film and a manufacturing apparatus and method thereof, and more particularly, to a superlattice coating film and a manufacturing apparatus and method thereof that can easily control the thickness of the superlattice coating film while maintaining high hardness characteristics will be.

In general, the ultrahard material refers to a material exhibiting a hardness of 40 GPa or more. They occur mainly in materials such as diamond (100GPa) and CBN (60GPa), which are composed of strong covalent bonds. However, such a diamond thin film has a disadvantage of being rapidly oxidized at high temperature and having low thermal expansion rate, making it difficult to be used as a protective film of most metal materials. Moreover, the diamond thin film has a high reactivity with iron and cannot be used as a protective film for tool steel and mold steel.

Accordingly, in order to solve the problems of the diamond-based thin film, a superlattice coating film such as TiN / AlN, TiN / VN, TiN / NbN having high hardness has been proposed. Such a superlattice coating film has been reported to have an extremely high hardness of about 50 to 60 GPa depending on the addition of the third and fourth elements constituting the superlattice.

However, conventional nitride based superlattice coatings such as TiN / AlN, TiN / VN, TiN / NbN have a disadvantage of poor adhesion to the base material due to high hardness and poor lubrication characteristics. In addition, it is difficult to apply to most industrial machinery fields unless the thickness is precisely controlled.

Accordingly, it is an object of the present invention to provide a nitride-carbide-based superlattice coating film which can control the thickness precisely and is excellent in high hardness, adhesion and lubricity.

In addition, another object of the present invention is to provide an apparatus for producing a superlattice coating film which can provide a nitride-carbide-based superlattice coating film which can control the thickness precisely and which is excellent in high hardness, adhesion and lubricity.

In addition, another object of the present invention is to provide a method for producing the superlattice coating film.

1 is a cross-sectional view of the superlattice coating film according to the present invention.

Figure 2 schematically shows a superlattice coating apparatus according to the present invention.

3 is a transmission electron micrograph of the superlattice coating membrane of the present invention formed according to Experiment 1 of the present invention.

4 is a transmission electron micrograph of the superlattice coating membrane of the present invention according to Experiment 2 of the present invention.

(Explanation of symbols for the main parts of the drawing)

10,25-Base Materials 11-Superlattice Wear Resistant Layer

12-Stress Relieving Layer 21-Vacuum Box

22-vacuum pump 23-WC cathode arc source

24-Ti cathode arc source 26-rotary jig

27-gas flow control part 34, 110a-TiN layer

35, 110b-WC layer 100-superlattice coating

In order to achieve the above object of the present invention, according to one aspect of the present invention, a base material; At least one layer formed on the base material includes a super lattice wear resistant layer, wherein the super lattice wear resistant layer is characterized in that the TiN layer and the WC layer are alternately laminated at least one or more times. Here, when two or more superlattice wear resistant layers are laminated, a stress releasing layer is interposed between the superlattice wear resistant layers, and the stress releasing layer is formed of a mixed layer of Ti and WC. In addition, the total thickness of the film laminated at least once of the superlattice wear resistant layer and the stress releasing layer is characterized in that 3 to 5㎛.

According to another aspect of the present invention, there is provided an apparatus for manufacturing a superlattice coating film comprising a superlattice wear resistant layer comprising a laminated film of a TiN layer and a WC layer, comprising: a vacuum chamber in which a coating process is performed, and A vacuum pump for reducing the pressure to a predetermined pressure, at least one WC cathode arc source mounted in the vacuum chamber to allow the WC layer to be deposited when an arc (ARC) discharge is generated, and disposed to face the WC cathode arc source At least one Ti cathode arc source for depositing a TiN film, a vacuum jig and an insulated rotary jig so as to apply a DC bias voltage while alternately transferring the front of the cathode arc source of Ti and WC respectively; The gas flow control unit for adjusting the flow rate of the reactive gas, that is, N ₂ , Ar gas for compound synthesis in the vacuum box, the rotary jig The thickness of the TiN layer and the WC layer is controlled by the rotation speed. Here, as the rotational speed of the rotary jig increases, the thickness of the TiN layer and the WC layer is reduced.

According to still another aspect of the present invention, a method of manufacturing a superlattice coating film on a base material, wherein the base material is charged into a vacuum box in which Ti and WC cathode arc sources are opposed to each other, and then a rotary type disposed between the arc sources. Fixing the base material to a jig; Applying a DC bias voltage to each arc source; And rotating the rotary jig so that the base material alternately approaches each arc source to which the DC bias voltage is applied, and sequentially forming a TiN layer and a WC layer on the base material to form a superlattice wear resistant layer. And forming the superlattice wear resistant layer is repeated at least once. Here, the method further includes interposing a stress releasing layer between the at least two or more superlattice wear resistant layers. In this case, the superlattice wear resistant layer may be formed of one selected from the group consisting of a physical vapor deposition (PVD) method, more preferably, a cathode arc ion plating method, a magnetron sputtering method, an ion beam sputtering method, an electron beam deposition method, and a resistive heating deposition method. Can be. In addition, the superlattice wear resistant layer may be formed of one selected from the group consisting of chemical vapor deposition (CVD), more preferably high temperature CVD, plasma CVD, and metal organic chemical deposition (MOCVD). In addition, the thickness of the superlattice wear-resistant layer is characterized in that the decrease as the rotational speed of the rotary jig increases.

According to the present invention, a superlattice coating film is formed by laminating at least one or more wear-resistant layers and a stress releasing layer composed of a laminated film of a TiN layer and a WC layer, and by controlling the rotational speed of the jig in the coating apparatus, the superlattice coating film It is possible to easily adjust the thickness of the TiN layer and WC layer constituting the. In addition, a superlattice is formed between the WC layer and the TiN layer, thereby ensuring high hardness characteristics.

In addition, by interposing a stress releasing layer that eliminates residual stresses between the superlattice wear resistant layers, not only can the residual stresses be reduced by 50% or more, but also the adhesion characteristics are improved.

(Example)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of the superlattice coating film according to the present invention, Figure 2 is a schematic view showing a superlattice coating device according to the present invention. 3 is a transmission electron micrograph showing the cross-sectional structure of the superlattice coating film of the present invention formed according to Experiment 1 of the present invention, Figure 4 is a cross-sectional structure of the superlattice coating film of the present invention according to Experiment 2 of the present invention Transmission electron micrograph shown.

First, the superlattice coating film according to the present invention will be described with reference to FIG. 1.

The superlattice coating film 100 of the present invention is formed on the base material 10 of the high-speed coating oral or superalloy material, the superlattice coating film 100 is a single or multiple superlattice wear resistant layer 11 having an ultra-high hardness It is formed into a structure that is stacked once. At this time, when the superlattice wear resistant layer 11 is formed in a laminated structure, in order to solve the stress between the superlattice wear resistant layers 11 and improve the adhesion, a stress releasing layer 12 is interposed.

Here, the superlattice wear resistant layer 11 having an ultra high hardness is composed of a laminated film in which the TiN layer 110a and the WC layer 110b are laminated at least once, and in this embodiment, one superlattice wear resistant layer ( 11) alternately stacked two times, for example. In addition, the TiN layer 110a and the WC layer 110b are preferably formed to have a thickness of several nm, respectively. In addition, the stress releasing layer 12 is formed of a mixture of Ti and WC, which is a material constituting the wear resistant layer 11 to buffer the stress between the superlattice wear resistant layer 11, the superlattice wear resistant layer 11 Improve the adhesion properties while minimizing the stress between As such, the total thickness of the superlattice coating layer 100 including the superlattice wear resistant layer 11 and the stress releasing layer 12 is preferably about 3 to 5 μm.

As such, when the superlattice coating film 100 is formed to include the superlattice wear resistant layer 11 in which the TiN layer 110a and the WC layer 110b are stacked a plurality of times, the TiN layer 110a and the WC layer 110b are formed. This superlattice is synthesized into a new ultrahard composite coating film that cannot be obtained with a single layer coating film.

In addition, the superlattice coating film 100 is formed in the following superlattice coating apparatus.

Referring to FIG. 2, the superlattice coating apparatus of the present invention includes a vacuum chamber 21 in which a coating process is performed, a vacuum pump 22 for reducing the pressure of the vacuum chamber 21 to a predetermined pressure, and the vacuum. At least one WC cathode arc source 23 mounted in the box 21 and arranged to be opposed to the WC cathode arc source 23 to allow the WC film to be deposited when an arc (ARC) discharge occurs, at least to allow the TiN film to be deposited. One or more Ti cathode arc sources 24 and the base material 25 are vacuumed so as to apply a DC bias voltage while alternately passing in front of the cathode arc sources 23 and 24 of Ti and WC, respectively. And a rotary jig 26 insulated from each other, and a gas flow rate controller 27 for adjusting a flow rate of an inert gas, that is, N ₂ and Ar gas, for compound synthesis. Here, the vacuum pump 22 serves to drop the pressure of the vacuum box 12 to about 10 ⁵ Torr or less.

This superlattice coating film 100 is formed in the following manner in the coating apparatus described above.

First, the base material 25 is charged into the vacuum box 21 of the superlattice coating apparatus and fixed to the rotary jig 26. Subsequently, the rotary jig 26 is rotated at a predetermined speed while a DC bias voltage is applied to each of the arc sources 23 and 24. Then, the TiN layer 110a (see FIG. 1) and the WC layer 110b (see FIG. 1) are alternately stacked at least one or more times on the base material 25, and the superhard superlattice wear resistant layer 11 is formed on the base material 25. 25). In this case, each of the TiN layer 110a and the WC layer 110b may be formed in the vacuum chamber 21 of the coating apparatus by, for example, cathode arc ion plating, which is one of physical vapor deposition methods. That is, a direct current power source having a low voltage and high current is applied to a conductive cathode made of a coating material, and then a cathode arc is generated to the grounded trigger electrode. The magnetic field is then confined and held by the magnetic surface to the cathode surface, producing a vapor of metal by the high temperature of the arc. At this time, the high heat generated on the cathode and the electrons are emitted, the plasma is generated in front of the cathode, the surface heating, cleaning and coating of the base material by the charged particles passing through the plasma. In addition, the TiN layer 110a and the WC layer 110b may be formed by a magnetron sputtering method, an ion beam sputtering method, an electron beam deposition method, a resistive heating deposition method, etc., in addition to the above-described physical vapor deposition ion plating method. Can be. In addition, the TiN layer 110a and the WC layer 110b may be formed by a CVD method such as high temperature chemical vapor deposition (CVD), plasma CVD, and metal organic chemical vapor deposition (MOCVD). In this way, the superlattice coating film 100 of the single superlattice wear resistant layer 11 is formed, or the stress releasing layer 12 is formed on the superlattice wear resistant layer 11, and the stress releasing layer is formed. (12) A method of laminating the superhard superlattice wear resistant layer 11 on the top is repeated at least one or more times to form a multi-layered superlattice coating film 100. At this time, the rotary jig 26 serves to transfer the base material 25 to alternately pass through the front of the cathode arc sources 23 and 24 of Ti and WC, respectively, and thus, the TiN layer is rotated by the rotational speed of the rotary jig 26. 110a and the thickness of the WC layer 110b is adjusted.

The following Experiment 1 is an experiment to measure the thickness when the rotational speed of the rotary jig in the coating apparatus is adjusted.

First, the process conditions in the coating equipment is set as follows, and then the superlattice coating film is deposited.

Process pressure: 1 × 10 ² to 2 × 10 ² Torr

Gas flow rate: Ar-30 to 50 sccm

N ₂ - 120 sccm to about 140

Arc Cathode:

Cathode 1-Pure Ti, provided that the metal has a purity of 99.9%.

Cathode 2-WC + Co Alloy (Co 8%)

Current density: 190 to 210 W / cm 2

Base material temperature: 250 to 350 ℃

Jig rotation speed: 4, 8, 12 rpm

Base material bias: DC -180 to -220V

After setting the process conditions as described above, when the rotational speed of the jig 26 was changed to 4, 8, and 12 rpm to form a superlattice coating film, the repetition period of the TiN layer 110a and the WC layer 110b was 12, 9 and 5 nm. As a result, the thickness of the nm grade TiN layer 110a and WC layer 110b can be precisely controlled by the rotation speed of the jig 26.

FIG. 3 is a transmission electron micrograph showing the cross-sectional structure of the superlattice coating film when the jig 26 is rotated at 12 rpm and the superlattice coating film is formed, and the part shown thick and dark on the base material (not shown). The TiN layer 34 and the part shown by the white line was the WC layer 35, and the repetition period, that is, the thickness was measured at 5 nm. In addition, the TiN layer 34 and the WC layer 35 formed a superlattice with each other, and the hardness thereof was measured to be about 50 GPa. Accordingly, it has a high hardness characteristic as compared with each of TiN (hardness 22 GPa) and WC (hardness 20 GPa) which do not form a superlattice.

In addition, the following Experiment 2 is an experiment for examining the adhesion characteristics and the residual stress degree of the superlattice coating film when the stress releasing layer 12 is interposed, and the experimental conditions are as follows.

Process pressure: 1 × 10 ² to 2 × 10 ² Torr

Gas flow rate: Ar-30 to 50 sccm

N ₂ - 120 sccm to about 140

Arc Cathode:

Cathode 1-Pure Ti, provided that the metal has a purity of 99.9%.

Cathode 2-WC + Co Alloy (Co 8%)

Deposition time of TiN layer and WC layer (wear resistant layer): 2 minutes 10 seconds

Stress release layer deposition time: 50 seconds

Current density: 190 to 210 W / cm 2

Base material temperature: 250 to 350 ℃

Jig rotation speed: 12 rpm

Base material bias: DC -180 to -220V

4, the bright portion is the TiN layer 46, the dark portion is the WC layer 47, and the TiN layer 46 and the WC layer 47 are formed with a 5 nm repetition period. In addition, a stress releasing layer 48 of a mixed material of Ti and WC material is observed between the light and dark portions. At this time, the residual stress when only the TiN layer 46 and the WC layer 47 were laminated without the stress releasing layer 48 was 8 GPa, but the residual stress after the stress releasing layer 48 was 2 GPa. Was measured. As described above, as the stress releasing layer 48 is interposed, the residual stress of the superlattice coating film is reduced by 50% or more, and the adhesion between the superlattice coating film and the base material is improved.

As described in detail above, according to the present invention, the superlattice coating film is formed by laminating at least one or more wear-resistant layers and a stress releasing layer composed of a laminated film of a TiN layer and a WC layer, but the rotational speed of the jig in the coating apparatus By controlling the thickness of the TiN layer and WC layer constituting the superlattice coating film can be easily adjusted. In addition, a superlattice is formed between the WC layer and the TiN layer, thereby ensuring high hardness characteristics.

In addition, by interposing a stress releasing layer that eliminates residual stresses between the superlattice wear resistant layers, not only can the residual stresses be reduced by 50% or more, but also the adhesion characteristics are improved.

As described above, the superlattice coating film of the present invention is excellent in adhesion characteristics and easily adjusts the thickness while securing high hardness characteristics, and thus is applicable to the field of industrial machinery requiring precise thickness.

In addition, the present invention is not limited to the above embodiments, and various modifications can be made.

Claims (15)

Base material; At least one layer formed on the base material includes a super lattice wear resistant layer, The superlattice wear-resistant layer is a superlattice coating film, characterized in that the TiN layer and the WC layer are laminated at least once alternately. The superlattice coating film according to claim 1, wherein when two or more layers of the superlattice wear resistant layer are laminated, a stress releasing layer is interposed between the superlattice wear resistant layers. The superlattice coating film of claim 2, wherein the stress releasing layer is a mixed layer of Ti and WC. The superlattice coating film of claim 3, wherein the total thickness of the at least one layer of the superlattice wear resistant layer and the stress releasing layer is 3 to 5 μm. An apparatus for manufacturing a superlattice coating film comprising a superlattice wear resistant layer comprising a laminated film of a TiN layer and a WC layer, Vacuum chamber in which the coating process proceeds, A vacuum pump for lowering the pressure of the vacuum box by a predetermined pressure; At least one WC cathode arc source mounted in the vacuum chamber to allow the WC layer to be deposited when an arc (ARC) discharge occurs; At least one Ti cathode arc source arranged to face the WC cathode arc source and allowing the TiN film to be deposited; A rotary jig and an insulated rotary jig for applying a direct current bias voltage while the base material is alternately transferred in front of the cathode arc source of Ti and WC, It includes a gas flow rate control unit for adjusting the flow rate of the inert gas, that is, N ₂ , Ar gas for compound synthesis in the vacuum chamber, Apparatus for manufacturing a super lattice coating film, characterized in that the thickness of the TiN layer and WC layer is controlled by the rotational speed of the rotary jig. 6. The apparatus of claim 5, wherein the vacuum pump drops the pressure of the vacuum box to about 10 ⁵ Torr or less. The apparatus of claim 5, wherein the thickness of the TiN layer and the WC layer decreases as the rotational speed of the rotary jig increases. As a method of manufacturing a superlattice coating film on a base material, Inserting the base material into a vacuum box in which Ti and WC cathode arc sources are opposed to each other, and then fixing the base material to a rotary jig disposed between the arc sources; Applying a DC bias voltage to each arc source; And Rotating the rotary jig so that the base material alternately approaches each arc source to which the DC bias voltage is applied, and sequentially forming a TiN layer and a WC layer on the base material to form a superlattice wear resistant layer. and, Forming the superlattice wear resistant layer is a method for producing a superlattice coating, characterized in that repeated at least one or more times. The method of claim 8, further comprising interposing a stress releasing layer between the at least two or more superlattice wear resistant layers. 10. The method of claim 9, wherein the stress releasing layer is formed of a mixture of Ti and WC. 10. The method of claim 8 or 9, wherein the superlattice wear resistant layer is formed by PVD (physical vapor deposition). The superlattice according to claim 11, wherein the PVD method for forming the superlattice wear resistant layer is selected from the group consisting of cathode arc ion plating method, magnetron sputtering method, ion beam sputtering method, electron beam deposition method and resistive heating deposition method. Coating film production method. delete delete The method of claim 8, wherein the thickness of the superlattice wear resistant layer decreases as the rotational speed of the rotary jig increases.