KR100923291B1 - Method for coating DLCDiamond like carbon film with nitriding hardening on the vane of air compressor by low temperature PECVD - Google Patents

Abstract

The present invention uses low-cost materials to minimize the manufacturing process required for the production of the product to secure the price competitiveness of the product, low temperature nitriding and DLC coating method of the air compressor vanes to have surface roughness, friction coefficient, adhesion, corrosion resistance It is about.

To this end, while maintaining the pressure inside the chamber to 0.1torr or less, while maintaining the temperature at 450 ℃ or less, while forming a nitride layer on the surface of the substrate while N ₂ and H ₂ in the chamber, Ar inside the chamber While applying a pulsed bias voltage to the substrate to activate the surface of the substrate, the pressure of the chamber is maintained at 2torr or less, the temperature is lowered below 400 ℃, Ar and H ₂ and a hydrocarbon compound and It is characterized in that the DLC layer is coated on the surface of the substrate by adding TMS and NH ₃ .

According to the above configuration, the material of the vane is made of low-cost material, the product manufacturing process is simplified, the price competitiveness of the product is secured, and the hardness is increased through the nitride layer and carbon-based DLC layer coating, and the product has excellent surface roughness. It has the effect of maximizing the corrosion resistance and lubricity, durability and life of the product.

Air compressors, vanes, nitride layers, DLC layers, nitrogen, low temperature.

Description

Method for coating DLC (Diamond like carbon) film with nitriding hardening on the vane of air compressor by low temperature PECVD}

The present invention relates to a DLC coating method, and more particularly, by using a low-cost material, simplifying and minimizing the manufacturing process required for the production of the product to secure price competitiveness of the product, and forming a nitride layer and a DLC layer to obtain a surface roughness. It is to provide a low temperature nitriding and DLC coating method of the air compressor vane excellent in the coefficient of friction and adhesion, and corrosion resistance.

In general, in the case of vanes used in automobile air compressors, the gap between the housing and the housing is extremely small due to the high speed rotation in addition to the surface hardness, so that corrosion resistance and lubrication characteristics are required along with precision problems. Such a vane is a part that is continuously used for a long time, and the compression efficiency decreases with noise generation when the part is worn or the lubricity decreases, and thus, the performance of the air conditioning is degraded and eventually leads to energy loss.

Conventional vanes are usually produced through a process as shown in FIG. 1. That is, after precision processing of heat-treated steel materials and the like and heat treatment, it is polished through polishing. Then, after nitriding, polishing is performed through lapping to make a mirror surface, oxynitride again, and produce a product through an oil wetting process. In addition, the surface of the hiss is polished by another production method, and then the CrN coating is applied by using a PVD process of about 5 ~ 7㎛.

However, in the case of vanes produced through such a method, there is a problem that leakage may occur due to the housing and abrasion, and also in the summer use, moisture remains on the surface of the vanes, leading to corrosion by the refrigerant gas, resulting in a long service life. There is also a problem of deterioration. Furthermore, as shown in FIG. 2, the adhesion of the product is poor, and there is a problem that corrosion occurs along the interface of pure Cr formed by the drop net during production.

In particular, since the manufacturing process for the production of the product is complicated and expensive high-grade steel grade is used as the material used for the production of the product, the unit price of the product increases due to the continuous increase in the price of the material, which leads to a price competitiveness of the product. Falling lungs occurred.

On the other hand, in terms of hardness and lubrication properties, most of them are given through surface hardening heat treatment, and most of them are improved in surface hardness and lubricity through nitriding treatment. Nitriding treatments include gas nitriding, ion nitriding, and salt bath nitriding. However, these nitriding treatments lead to a reduction in surface roughness due to compound layer formation and a burden on production costs due to the occurrence of post-processing. In addition, in order to further maximize the physical properties of the component, the coating layer by arc ion plating, ion implantation, magnetic sputtering and CVD is applied to the compound layer formed during nitriding. Due to this brings about a decrease in adhesion of the coating film is a post-processing process is essential.

DLC (Diamond Like Carbon) coating has a relatively high coating hardness along with chemical resistance and lubricity, so that the mechanical properties of the parts can be improved by utilizing the characteristics. However, the DLC coating has a large disadvantage that the manufacturing process is complicated, the production cost is difficult to apply, and above all, the material to be applied is limited.

In addition, since most DLC coating fabrication processes are made by Arc Ion Plating, Ion Implantation, Magnetic Sputtering, etc., the coating affects the linearity of ions in the process. There is a problem that the coating also has a directivity. In order to solve the above problems, DLC coating is performed by using PECVD (Plasma Enhanced Chemical Vapor Deposition) when the shape of the product is complicated, but problems in adhesion and life have arisen. PECVD technology is somewhat incomplete.

The present invention has been made to solve the conventional problems as described above, and by using a low-cost material to simplify and minimize the manufacturing process required for the production of the product to reduce the unit cost of the product to improve the price competitiveness The present invention provides a low temperature nitriding of a die vane and a DLC coating method.

It is another object of the present invention to form a nitride layer using nitrogen, and to form a carbon-based DLC coating layer having excellent corrosion resistance and lubricity, thereby providing excellent surface roughness, coefficient of friction, adhesion, and low temperature nitriding of air compressor vanes. And DLC coating method.

According to the configuration of the present invention for achieving the above object, the pressure inside the chamber is maintained at 0.1torr or less, and the temperature is maintained at 450 ° C or lower, while N ₂ and H ₂ are 1: 3 in the chamber. Forming a nitride layer on the surface of the substrate while charging at a ratio; A sputtering process of activating the surface of the substrate by applying a pulsed bias voltage to the substrate for 10 to 30 minutes while introducing Ar into the chamber; Maintaining the pressure of the chamber at 2torr or less, lowering the temperature to 400 ° C or lower, and injecting Ar, H ₂ , a hydrocarbon compound, TMS, and NH ₃ into the chamber to coat the DLC layer on the surface of the substrate. Characterized in that.

Through the above problem solving means, the present invention, without the use of expensive high hess, the low cost of the material can be surely lowered the material cost, the product manufacturing process can be simplified to secure the price competitiveness of the product It has an effect.

Furthermore, by forming a nitride layer at low temperature, it produces a product with superior surface roughness while making hardness higher than that of a conventional high-speed steel, and improves the corrosion resistance and lubricity of the product by coating a carbon-based DLC layer at low temperature, as well as durability of the product. It also has the effect of maximizing life expectancy.

In addition, by maximizing hardness, heat resistance, and lubrication characteristics, it is possible to reduce production costs, increase overall production efficiency, and improve lifespan.In the case of air compressor equipped with vane, it is quiet at high speed and prevents wear and corrosion. There is also.

When described in detail with reference to the accompanying drawings a preferred embodiment of the present invention.

The low temperature nitriding and DLC coating method of the air compressor vane of the present invention comprises a nitride layer forming step (P10), a sputtering step (P20), and a DLC layer coating step (P30).

First, in the nitride layer forming process P10, a reaction gas containing N ₂ is added to the chamber 40 to improve adhesion to the DLC layer 30, and the substrate is introduced into the chamber by nitriding at a high vacuum low temperature. 10) The nitride layer 20 is formed in the surface.

3 to 5, after loading the substrate 10 to be coated in the chamber, the pressure of the chamber 40 is maintained at 0.05 to 0.1 torr using the vacuum pump 41. And while maintaining the temperature below 450 ℃, while entering the inside of the chamber 40 in the ratio of 1: ₂ N ₂ 100sccm, H ₂ 300sccm through the gas inlet unit 42 for 60 to 120 minutes The nitride layer 20 is coated on the surface of the substrate 10 to improve adhesion. In this case, the inside of the chamber is maintained in a high vacuum state and N ₂ is introduced into the inside, thereby allowing the surface of the substrate 10 to be nitrided in a state.

Here, the substrate 10 uses a material having a lower unit cost than the existing high-speed steel by selecting any one of the STD11 type and the DC51 type metal corresponding to the hardness slightly after heat treatment. Such substrate 10 is charged to the chamber by polishing after precision processing and heat treatment before the nitriding treatment.

The sputtering process (P20) is for activating the surface of the substrate 10 and removing nitride from the surface of the substrate 10. The sputtering process (P20) powers the substrate 10 at a voltage of 1000 V for 10-30 minutes while introducing Ar 50 sccm into the chamber. A pulsed bias voltage of 10-20 mA is applied through the supply 43 to activate the surface of the substrate 10.

In the DLC layer coating process (P30) by adding NH ₃ with the reaction gas for improving the corrosion resistance and mold release properties and lubricity inside the chamber 40, the powder is not generated on the surface of the substrate 10, the hardness is improved DLC (Diamond Like Carbon) layer.

In more detail, the pressure inside the chamber 40 is maintained at 1.8 to 2 torr, the temperature is lowered to 400 ° C. or lower, and the Ar 400sccm and H are formed through the gas inlet unit 42 inside the chamber 40. ₂ 400sccm, a hydrocarbon compound, TMS 5sccm and NH ₃ is added to coat the DLC layer 30 on the surface of the substrate (10).

Here, as the hydrocarbon-based compound, C ₂ H ₂ , CH ₄ , C ₆ H ₆ and the like may be used, but other hydrocarbon-based compounds may be used. Preferably, CH ₄ is appropriately used. 600 sccm is added. The NH ₃ is added in an amount of about 1.3 to 5% based on the volume of the hydrocarbon compound, and about 15 sccm is added thereto.

In brief, the coated DLC was produced by a scientist in the United States around the 1970s by using an ion-beam evaporation method of graphite as a raw material, which is very similar to diamond. It was said.

DLC is an amorphous structure, which is structurally different from diamond crystals, but is very close to diamond. In addition, the DLC is remarkably different from conventional hard films such as TiN and TiCN, which can be said to have a very low friction coefficient surface.

On the other hand, the pulsed bias voltage used throughout the low temperature nitriding and DLC coating method of the air compressor vane of the present invention includes all DC, Pulse DC, RF, the pulsed bias voltage is frequency, Duty The three variables of positive voltage can be kept variable.

Here, the frequency (pulse frequency) basically means the number of waveforms according to the time to periodically discharge the pulse of negative voltage, Duty refers to the application time of the negative voltage and positive voltage to the same frequency, in particular Pulsed DC In the case of the power supply, the process can be carried out by changing the applied frequency within a range of 1 kHz to 1000 kHz to give a duty change which is the width of the negative voltage.

In order to coat the DLC layer 30, which is an insulator film, symmetrical and asymmetrical pulses should be applied, and asymmetrical pulses may be subjected to a process by changing a positive voltage in a range of 0 to 500V, and a positive voltage higher than that may be applied. .

Referring to the operation and effect of the present invention configured as described in detail as follows.

In order to coat the DLC layer 30 on the substrate 10 through the low temperature nitriding and DLC coating method of the air compressor vane of the present invention, the pressure inside the chamber is set to 0.1 when the substrate 10 is embedded in the chamber. Maintaining below torr, a total flow rate of 400 sccm in a ratio of 1: 3 of N ₂ and H ₂ is introduced into the chamber and nitriding is performed at a temperature of 450 ° C. or lower. In addition, the nitriding treatment is performed by forming a high hardness nitride layer 20 having a thickness of 60 to 100 μm on the surface of the substrate 10 for about 2 hours by using a low voltage high density plasma process having a power of 10 kV and 500 V. The condition which improves the adhesive force with 30) is provided.

Here, the inside of the chamber is gradually heated, but the nitriding treatment is performed at a low temperature of 450 ° C. or less to minimize heating in consideration of thermal expansion of the STD11 and DC51 series metals used as the substrate 10.

Thereafter, the sputtering process (P20) is performed for 10 to 30 minutes while changing the atmosphere by introducing a flow rate of about 50 sccm of Ar into the chamber.

Then, after lowering the temperature inside the chamber to 400 ° C. or less, Ar 400sccm and H ₂ 400sccm, CH4 600sccm, TMS 5sccm and NH ₃ 15sccm were added to coat the hardened corrosion resistant DLC layer 30 on the surface of the substrate 10. By doing so, the vane product through the DLC layer 30 can exhibit the characteristics of corrosion resistance and durability, reduce noise, and improve the life.

In particular, the coating method of the present invention can reduce the material cost by about a quarter by using a low-cost material without using expensive vanes, and can simplify the product manufacturing process to secure the price competitiveness of the product Will be.

Furthermore, the present invention performs nano-nitridation by injecting nitrogen in a low-voltage high-density plasma state, and combines the low-temperature DLC process with excellent performance thereon, resulting in a high quality composite surface modification process, which is quiet at high speed and does not wear and corrode. High quality vane products can be produced.

Figure 6 shows the hardness profile of the nitride layer 20 formed through the present invention, the surface hardness of the vane subjected to nitriding only shows a hardness of 1100HV as shown, compared to the hardness of the conventional highs 850 ~ 900HV, Although not yet, the final surface hardness of the vane coated through the present invention compared to about 1000 ~ 1050HV when the oxynitride has a hardness of 1800 ~ 2000HV.

And, Figure 7 shows the friction surface and coefficient of friction of the product coated through the coating method according to the invention, Figure 8 shows the corrosion resistance test results of the product coated through the coating method according to the invention, the friction coefficient It is very low and can exhibit excellent lubrication performance, it can be seen that the fine abrasion traces on the surface, but without the powder at all smooth. In addition, the corrosion resistance is about 10000 times higher than the conventional DLC process or oxynitride process, and the corrosion potential is also known to be noble, thereby improving the performance of the product.

As described above, the coating method of the present invention can maximize the hardness, heat resistance, and lubrication characteristics, thereby reducing the production cost, increasing the overall production efficiency, and improving the lifespan, and furthermore, the application and application of the mechanical parts requiring the same characteristics. This is possible, which in turn can lead to increased production efficiency and improved product durability.

On the other hand, since the present invention coats the DLC layer 30 through the addition of NH ₃ gas, powder is not formed during the process, so the roughness of the coating surface is high and excellent adhesion to the DLC layer 30 can be ensured. Thus, in FIG. 9, the adhesion evaluation of the present invention was tested, and the binding test by the hardness indenter and the test result photograph (image) of the scratch test were respectively shown.

That is, the experimental photograph shown in FIG. 9 was nitrided with N ₂ 100 sccm and H ₂ 300 sccm under a pressure of 0.01 torr and a temperature of 450 ° C. under the conditions of the nitride layer forming process (P10), and DLC layer coating process (P30). The DLC layer 30 was coated by adding Ar 400sccm, H ₂ 400sccm, CH ₄ 600sccm, TMS 5sccm, NH ₃ 15sccm at a pressure of 2torr or less and a temperature of 400 ° C or less.

As shown in the result of the bonding test by the hardness indenter on the substrate 10 coated under these conditions, it can be seen that the surroundings of the indenter are not peeled off or cracks are generated and the clean indentation image is shown. It can be seen that the coated film is not torn off, the adhesion is excellent.

Through the experimental results as described above, the present invention improves the adhesion by forming the nitride layer 20 through the nitriding treatment, as well as there is no powder by the reaction product at this time, it is excellent in productivity and significantly lower the defective rate of the product. There are advantages to it.

That is, FIG. 10 shows the vane image coated with the DLC layer 30 and the pre-coating image according to the present invention, thereby preventing the formation of powder during the process to ensure a product having a smooth and glossy surface. As a result, it can be confirmed that industrial production parts having excellent performance can be manufactured.

On the other hand, the present invention has been described in detail only with respect to the specific examples described above it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, it is natural that such variations and modifications belong to the appended claims. .

1 is a block diagram showing a vane production process according to the prior art,

Figure 2 is a photograph showing the results of the bonding test by the hardness indenter and the scratch test to the substrate coated by the prior art, respectively,

Figure 3 is a block diagram sequentially listing the DL coating method of the present invention,

Figure 4 is a schematic diagram schematically showing a coating apparatus used in the present invention,

Figure 5 is a perspective view schematically showing a structure coated by the coating method of the present invention,

6 is a graph showing the hardness profile of the nitride layer coated by the present invention,

7 is a photograph showing the friction surface and coefficient of friction according to the friction test results of the substrate coated by the present invention,

8 is a graph showing the results of the corrosion resistance of the substrate coated by the present invention,

9 is a photograph showing the test results of the bonding test by the hardness indenter and the scratch test to the substrate coated by the present invention, respectively;

10 is a real product picture and a product picture before coating by the present invention,

* Description of Major Symbols in Drawings *

10 base material 20 nitride layer

30: DLC layer 40: chamber

41: vacuum pump 42: gas inlet device

43: power supply P10: nitride layer forming process

P20: Sputtering Process P30: DLC Layer Coating Process

Claims (3)

While maintaining the pressure inside the chamber 40 at 0.1torr or less and maintaining the temperature at 450 ° C or less, N ₂ and H ₂ were introduced into the chamber at a ratio of 1: 3, and the STD11 and DC51 types were Forming a nitride layer 20 on the surface of the substrate 10 made of any one of metals (P10); A sputtering process (P20) for activating the surface of the substrate 10 by applying a pulsed bias voltage to the substrate 10 for 10 to 30 minutes while introducing Ar into the chamber; After maintaining the pressure of the chamber 40 at 2torr or lower and lowering the temperature to 400 ° C or lower, Ar, H ₂ , a hydrocarbon compound, TMS, and NH ₃ are introduced into the chamber 40, The NH ₃ is an air compressor, characterized in that it comprises a step (P30) of coating the DLC layer 30 on the surface of the base material 10 by a ratio of 1.3 to 5% based on the volume of the hydrocarbon compound is added. Low temperature nitriding of vane and DLC coating method. delete delete

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