KR20070056580A - Method and facility for coating the 3-dimensional member with diamond-like carbon film by plasma cvd combined with plasma ion implantation - Google Patents

Abstract

A DLC(diamond-like carbon) coating method and a DLC coating apparatus which prevent shape or dimensions of a matrix from being changed, greatly improve interfacial adhesive force of a DLC film layer, enable a complicated shaped three-dimensional object to be coated to an uniform thickness, and make it not necessary to treat the surface of a DLC coated matrix or heat treat the DLC coated matrix are provided. In a method for modifying the surface of the matrix by plasma after injecting a gas material into a vacuum chamber in which a matrix is installed, a DLC(diamond-like carbon) coating method comprises: a cleaning step of cleaning the surface of the matrix with plasma generated using argon; a depositing step of forming a coating layer on the surface of the matrix by a plasma chemical vapor deposition method; an ion implanting step of implanting plasma ions into the coating layer formed matrix to form an ion mixed layer from a lower portion of the surface of the matrix to the coating layer; and a DLC coating step of forming a DLC film layer on the ion mixed layer by the plasma chemical vapor deposition method.

Description

DLC Coating Method and Coating Equipment {Method and facility for coating the 3-dimensional member with Diamond-Like Carbon Film by Plasma CVD combined with Plasma Ion Implantation}

1 is a working process diagram of the DLC coating method according to an embodiment of the present invention.

2 is a schematic configuration diagram of a DLC coating apparatus according to an embodiment of the present invention.

Figure 3 is a schematic diagram showing a process of forming a DLC film layer on the surface of the base material according to an embodiment of the present invention.

[Description of Drawing Reference]

10... Vacuum chamber 12.. gauge

21... Throttle valve 22.. Main valve

23... Vacuum pump 24... Four-line valve

25... Roughing valve 26.. Release valve

27... Rotary pump 28... pipe

30... Mass flow control unit 40.. Plasma generator

50... Pulse generator 60... PLC

70... Vent line 80... stage

100... Base material 200... Coating layer

300... Ion mixed layer 400... DLC film layer

The present invention is to form a diamond-like carbon film ("DLC film layer") on the surface of the base material of various tools, parts, molds, etc. made of metal or non-metal material, so that the base material durability / wear resistance / It relates to a method for improving lubricity and the like.

More specifically, when the diamond-like carbon film layer is formed on the surface of the base material, the DLC coating method and the coating which greatly improves the adhesion between the base material and the diamond-like carbon film layer by using plasma ion implantation and plasma chemical vapor deposition. Relates to a device.

In general, the base material of which the surface is protected by the DLC film layer can be utilized in various fields because it exhibits superior hardness / lubrication / abrasion resistance / friction characteristics / corrosion resistance and the like than when the surface is protected by other methods. However, since the DLC film layer does not adhere well to the base material, for example, a metal material, which does not contain carbide, there is a problem that peeling occurs easily.

As a method of suppressing or mitigating peeling of the DLC film layer, one of a method of increasing the process temperature to reduce the residual stress of the DLC film layer and a method of enhancing the interfacial adhesion of the DLC film layer is used. In particular, the present invention relates to a new method for enhancing interfacial adhesion.

Regarding the method of enhancing the interfacial adhesion, conventionally, the surface of the base material is cleaned with an organic solvent, and then the base material is installed in the CVD deposition apparatus / PVD deposition apparatus to apply the DLC coating or ② to the CVD deposition apparatus / PVD deposition apparatus. A method of sputtering the surface with argon to activate the surface and then applying a DLC coating was used.

However, even with such a preliminary step, sufficient interfacial adhesion is difficult to obtain. Recently, a method of forming an intermediate layer with a material having excellent chemical affinity between the base material and the DLC film layer has been widely used.

However, silicon, which is mainly used as a constituent of the intermediate layer, is brittle, so that the intermediate layer may be easily destroyed by external impact, and titanium may exist in the form of titanium dioxide in the intermediate layer due to high oxidizing power, thereby degrading adhesion. There is a concern.

Moreover, the conventional CVD deposition apparatus used for DLC coating can be applied only when the base material is a metal material because the process temperature reaches 800 ℃ to 1100 ℃, there is a disadvantage that the shape change and dimensional change of the base material is severe. In contrast, the PVD deposition apparatus has a process temperature of about 200 ° C to 500 ° C, which is more stable in shape and dimensions than the CVD deposition apparatus, and can work with non-metals, but the deposition of the DLC film layer simply stacked on the surface of the base material. (Iii) there is still a problem of peeling of the DLC film layer due to the structure and difficult to apply to a complicated three-dimensional article in the process conditions.

The present invention was devised to improve various problems of the conventional DLC coating process performed by the CVD deposition apparatus or the PVD deposition apparatus. ① It is operated at a lower process temperature than the conventional PVD deposition apparatus, so that there is almost no change in shape / dimension of the base metal. ② By applying plasma ion implantation method and plasma chemical vapor deposition method together for DLC coating, the interfacial adhesion of DLC film layer is greatly improved than before. There is no peeling problem. ③ Complex shape by ion induction action of plasma sheath formed around the base material during coating process. It is an object of the present invention to provide a DLC coating method and a coating apparatus that can be coated with a uniform thickness of 3D objects and do not need to surface-treat or heat-treat the ④ DLC-coated base material.

DLC coating method of the present invention for solving the above problems, for example, as described in claim 1, a method of modifying the surface of the base material by plasma after injecting the gaseous material into the vacuum chamber in which the base material is installed A deposition step of forming a coating layer on the surface of the base material by plasma chemical vapor deposition; An ion implantation step of injecting plasma ions into the base material on which the coating layer is formed to form an ion mixture layer from the lower surface of the base material to the coating layer after the deposition step; A DLC coating step of forming a DLC film layer on the ion mixed layer by a plasma chemical vapor deposition method after the ion implantation step ; It may be made, including.

At this time, it is preferable to clean the surface of the base material with a plasma generated using argon before the deposition step ( cleaning step ), as claimed in claim 2. According to this configuration, since the interfacial adhesion between the coating layer and the base material surface formed in the deposition step can be increased, the peeling problem can be greatly alleviated.

On the other hand, the DLC coating apparatus of one example that the above-described DLC coating method of the present invention can be effectively implemented, as can be seen from the contents of the attached FIG. 2 and the claims of the present application, the vacuum provided with a stage on which the base material is placed A chamber ; A vacuum unit connected to the vacuum chamber to maintain the interior of the chamber in a vacuum ; A mass flow control unit connected to the vacuum chamber and supplying a gaseous substance into the chamber; A plasma generator connected to the vacuum chamber to generate plasma in the chamber; It can be composed of a (high voltage) pulse generator for applying a (high voltage) pulse to the stage and a PLC for controlling the operations of the above-described units (vacuum unit, mass flow control unit, plasma generator, pulse generator).

Here, the stage may be installed in a rotatable structure on the inner bottom of the vacuum chamber via the mercury slipping element, according to this configuration can form a DLC film layer of a more uniform thickness on a three-dimensional object of a complex shape have. (Claim 6)

Hereinafter, a method of forming a DLC film layer on the surface of a three-dimensional object with a DLC coating apparatus according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

Preferred Embodiment

Attached Figure 1 is a work flow diagram of the DLC coating method according to an embodiment of the present invention, Figure 2 is a schematic diagram showing an example of the DLC coating apparatus that can be performed by the DLC coating method of Figure 1, Figure 3 It is a schematic diagram which plotted the state of the base material surface immediately after each (unit) process shown in 1 is completed.

As shown in FIG. 2, in the DLC coating apparatus of the present embodiment, a stage 80 supporting the base material 100 is installed at the inner bottom of the vacuum chamber 10, and a high voltage pulse is applied to the base material through the stage during coating. The pulse generator 50 is connected to the stage 80 outside of the vacuum chamber.

In addition, the plasma generator 40 is installed inside the upper surface of the vacuum chamber 10 in a form facing the stage 80. A gauge 12 and a vent line 70 are provided on the side of the vacuum chamber, and a mass flow control unit 30 is connected to the inside of the vacuum chamber 10 to supply a gaseous material according to a set supply amount.

In addition, the vacuum chamber is connected to a vacuum unit for keeping the interior in a vacuum state, which is shown in the drawing, the throttle valve 21, the main valve 22, the vacuum pump 23, the foreline valve ( 24, the roughing valve 25, the release valve 26, the rotary pump 27, the pipe 28 and the like.

In addition, a programmable logic controller (PLC) 60 manufactured in a configuration similar to a computer is electrically connected to each component so as to control the operations of the above-described parts. Here, the PLC can be replaced with a computer (PC) or used in combination with the computer.

More specifically, the vacuum chamber 10 of the present embodiment is made of a cylindrical pressure vessel having a diameter of 500 mm × length 500 mm, and the vacuum unit for reaching the internal pressure of the vacuum chamber to reach 5 × 10 ⁻⁶ Torr within 30 minutes. Was used.

In the DLC coating apparatus of this embodiment, the pulse power supply is applied so that a pulse is applied within a range of bias peak voltage: 50 Hz, peak current: 50 A, maximum width: 10 Hz, maximum rise time: 1.5 Hz, and maximum frequency: 1000 Hz. A hot filament was used as a plasma source. Here, RF or ERC microwaves other than hot filaments may also be used as the plasma source.

In addition, as a gaseous material supplied into the vacuum chamber through the mass flow control unit, Ar, CH ₄ , C ₂ H ₂ , C ₆ H ₆ , C ₇ H ₈ , Si (CH ₃₎ used in each unit process ₄ ) and the like.

In addition, 10 kW of 3-phase 220V power was used. In addition, to the stage produced in the form of a disk having a diameter of about 300 mm, a cooling device in which 10 to 20 liters of cooling water flows per minute was connected to prevent overheating.

As a result, the overall size of the DLC coating apparatus according to the present embodiment became about 1500 mm x 1400 mm x 1700 mm.

As shown in FIG. 1, in the DLC coating apparatus of the present embodiment, the DLC coating is performed through four working processes, and the internal pressure in each unit process (work) is maintained at 1 × 10 ^-4 Torr to ² × 10 ^-2 Torr. And the process temperature is kept below 200 ° C.

First, the mass flow control unit 30 connected to one side of the vacuum chamber while the base material 100 made of metal such as a tool / part / mold is supported on the stage 80 of the vacuum chamber 10. After argon (Ar) gas is injected into the vacuum chamber, plasma is generated to clean the surface of the base material at an intermediate energy level under conditions of a bias voltage of 7 to 15 Hz, a pulse width of 5 to 10 Hz, and a frequency of 100 to 1000 Hz. . ( Washing step ) In this way, the organic substance adhering to the base material is removed and the surface of the base material is activated by plasma.

Subsequently, a new gaseous material is introduced into the vacuum chamber through the mass flow control unit 30, but a gaseous material selected from methane / acetylene / benzene / toluene / titanium / silicon / silicon carbide series is introduced, and then a bias voltage of 2 to The coating layer 200 is formed on the surface of the base material by plasma chemical vapor deposition at a low energy level under conditions of 8 Hz, pulse width 10-100 Hz and frequency 100-1000 Hz. (Deposition step) In this way, and by plasma uniformly coated with an ultra-thin form of the carbon or titanium or silicon ions can the base material surface activation in the rinse step nm (nano) level glass from gaseous material, wherein the interface between the The adhesion is maintained at a very high level.

Subsequently, after injecting methane into the vacuum chamber, ions are implanted into the base metal at high energy levels under conditions of a bias voltage of 20 to 50 Hz, a pulse width of 5 to 10 Hz, and a frequency of 100 to 1000 Hz. ( Ion implantation step ) In this way, the carbon ions are incident almost vertically toward the plasma sheath, which looks like it is covering the base material, and the high energy carbon ions penetrate into the base material, and the low energy carbon ions are deposited on the coating layer. As a result, the ion mixture layer 300 extending from the lower surface of the base material to the coating layer is formed.

Thereafter, any one gaseous material selected from methane / acetylene / benzene / toluene-based materials is injected into the vacuum chamber, and a bias voltage of 2 to 8 Hz, a pulse width of 10 to 100 Hz, and a frequency of 100 to 1000 Hz is applied. The diamond-like carbon film layer 400 (DLC film layer) is formed on the surface of the ion mixed layer 300 at a low energy level by plasma chemical vapor deposition. ( DLC coating step ) In this way, the carbon-based DLC film layer is laminated on the ion-mixed layer containing carbon ions as a main component, and the adhesion between the coating layers is very high.

On the other hand, upon completion of the above-described DLC coating step, the vent line 70 is released to release the vacuum pressure, and then all operations of the DLC coating process are completed by taking out the base material through a door (not shown) provided on one side of the vacuum chamber. do.

Table 1 below is a comparison table for comparing the difference between the DLC coating process according to an embodiment of the present invention and the conventional PVD method can be seen that the present invention is very excellent in terms of friction coefficient, wear resistance and process temperature.

As described above, according to the DLC coating process according to an embodiment of the present invention, the surface of the base material is cleaned with argon of heavy energy, and then the coating layer is deposited by low energy plasma chemical vapor deposition. Then, carbon ions are deposited by high energy plasma ion implantation. After penetrating the base material to form the ion mixture layer, and again applying a low energy plasma chemical vapor deposition method to form a DLC film layer can be obtained a very excellent DLC film layer having a very high interfacial adhesion and no peeling problem.

In addition, since the DLC coating process according to an embodiment of the present invention is operated at a lower process temperature than the conventional PVD deposition apparatus, the shape stability and dimensional stability of the base material are very high.

In addition, due to the induction action of the plasma sheath formed around the base material, the DLC film layer can be easily formed even on a complicated three-dimensional object, and the layer thickness can be made uniform.

In addition, there is no need for any post-surface treatment or heat treatment to improve the interfacial adhesion between the coating layers, thereby reducing the overall work man-hours and reducing costs.

Claims (6)

In the method of modifying the surface of the base material by plasma after injecting a gaseous material into the vacuum chamber in which the base material is installed, Deposition step of forming a coating layer on the surface of the base material by plasma chemical vapor deposition; After the deposition step, the ion implantation step of forming an ion mixture layer from the lower surface of the base material to the coating layer by injecting plasma ions into the base material on which the coating layer is formed; After the ion implantation step, DLC coating step of forming a DLC film layer on the ion mixture layer by plasma chemical vapor deposition; DLC coating method characterized in that is carried out. The method of claim 1, As a previous step of the deposition step, DLC coating method characterized in that the cleaning step of cleaning the surface of the base material with a plasma generated by using argon (Argon) is carried out. The method of claim 2, The cleaning step A DLC coating method characterized in that it is carried out under conditions of a bias voltage of 7 to 15 Hz, a pulse width of 5 to 10 Hz, and a frequency of 100 to 1000 Hz with an argon gas injected into the vacuum chamber. The method according to claim 1 or 2 or 3, A) the deposition step is Gas material of any one selected from methane / acetylene / benzene / toluene / titanium / silicon / silicon carbide series is injected into the vacuum chamber, and then the bias voltage is 2 to 8㎸, the pulse width is 10 to 100㎲, the frequency is 100. Under conditions of ˜1000 Hz, B) the ion implantation step is Methane gas is injected into the vacuum chamber under a bias voltage of 20 to 50 Hz, a pulse width of 5 to 10 Hz, and a frequency of 100 to 1000 Hz. C) the DLC coating step is Under the conditions of a bias voltage of 2 to 8 kHz, a pulse width of 10 to 100 kHz, and a frequency of 100 to 1000 kHz in the state in which a gaseous material selected from methane / acetylene / benzene / toluene series material is injected into the vacuum chamber DLC coating method, characterized in that carried out. In the apparatus for forming a DLC film layer on the surface of the base material, A vacuum chamber having a stage on which a base material is to be placed; A vacuum unit connected to the vacuum chamber to maintain the interior in a vacuum; A mass flow control unit connected to the vacuum chamber and supplying a gas material therein; A plasma generator connected to the vacuum chamber to generate a plasma therein; A pulse generator for applying a high voltage pulse to the stage; And A PLC for controlling the operation of each unit; DLC coating device composed of. The method of claim 5, And the stage is rotatably installed via a mercury slipping element.

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