JP6842165B2 - Laminated coating film and its manufacturing method and piston ring - Google Patents

Description

The present invention relates to a laminated coating film, a method for producing the same, and a piston ring. More specifically, the present invention relates to a laminated coating film formed by a CrN layer and a hard carbon layer formed on a substrate, a method for producing the same, and the laminated coating. It relates to a piston ring provided with a covering film.

In recent years, the usage environment of piston rings has become more and more harsh due to the increase in output of automobile engines and compliance with exhaust gas regulations, and the sliding characteristics of piston rings (low friction, wear resistance, peeling resistance, etc.) ) Has been proposed in various ways.

For example, in Patent Document 1, a CrN coating is formed on the surface of a piston ring, and the crystals of the CrN coating are given a priority orientation of a (200) plane or a (111) plane, whereby wear resistance and peeling resistance are obtained. It has been proposed that excellent piston rings can be provided.

Further, in Patent Document 2, a CrN coating is formed on the surface of the piston ring, and the crystal structure of the CrN coating is described as an X-ray diffraction intensity ratio of the (111) plane to the (200) plane parallel to the surface: It has been proposed that a piston ring having excellent wear resistance and peeling resistance can be provided by configuring the piston ring so as to have a columnar crystal structure of 0.40 to 0.70.

However, although these techniques can secure wear resistance and peeling resistance in the piston ring, low friction resistance is not sufficient. Therefore, in Patent Document 3, a laminated coating film as shown in FIG. 4, that is, a base. By the laminated coating film in which the hard carbon layer 3 is laminated and coated on the CrN layer 2 formed on the material 3, in addition to the wear resistance and the peeling resistance of the CrN layer, the hard carbon layer has. It has been proposed that a piston ring having excellent sliding characteristics can be provided by exhibiting low frictional properties.

This hard carbon film is generally called by various names such as diamond-like carbon (DLC) film, amorphous carbon film, i-carbon film, diamond-like carbon film, etc., and is structurally not crystalline but non-crystalline. Classified as crystalline.

The hard carbon film is considered to have a mixture of a single bond (CC) as seen in a diamond crystal and a double bond (C = C) as seen in a graphite crystal. In addition to features such as high hardness, high abrasion resistance, and excellent chemical stability like diamond crystals, it also has features such as low hardness, high lubricity, and excellent compatibility with partners like graphite crystals. ing. Further, since it is amorphous, it has excellent flatness and low friction in direct contact with the mating material, that is, it has a small friction coefficient and excellent mating compatibility.

Japanese Patent No. 4382209 Japanese Patent No. 5065293 Japanese Unexamined Patent Publication No. 2015-86967

However, in the case of the technique shown in Patent Document 3, when the hard carbon layer is coated on the CrN layer, the CrN layer is polished in advance to remove particles on the surface of the CrN layer to form a CrN layer. Since it is necessary to ensure the adhesion of the hard carbon layer, it is not possible to perform the film formation of the CrN layer and the film formation of the hard carbon layer in a series of continuous steps in the same film forming apparatus, which is efficient. I could not say it. Further, it cannot be said that the adhesion of the hard carbon layer to the CrN layer is sufficiently secured, and the hard carbon layer is peeled off from the CrN layer so that the low friction property of the hard carbon layer can be stably exhibited. In some cases, it was not possible to secure sufficient excellent sliding characteristics.

Therefore, according to the present invention, when the hard carbon layer is coated on the CrN layer, it can be carried out in a series of continuous steps in the same film forming apparatus, and moreover, the adhesion of the hard carbon layer to the CrN layer is higher than before. In addition to the abrasion resistance and peeling resistance of the CrN layer, the low friction property of the hard carbon layer can be stably exhibited to ensure excellent sliding characteristics. The challenge is to provide.

As a result of repeated experiments and studies on the solution of the above problems, the present inventor appropriately forms the CrN layer when the CrN layer is formed prior to the formation of the hard carbon layer. If controlled, a hard carbon layer can be formed with excellent adhesion without performing the conventional polishing process on the CrN layer, and a series of continuous film formations can be performed in the same film forming apparatus, and the CrN layer can be formed. It has been found that in addition to the abrasion resistance and peeling resistance of the hard carbon layer, the low friction property of the hard carbon layer can be stably exhibited, and a laminated coating film having a long life and excellent sliding characteristics can be provided. ..

Specifically, when the CrN layer, which is the base coating film, is formed, the intensity ratio of X-ray diffraction to the (200) plane of the (111) plane [(111) / (200) diffraction intensity ratio] is 0.50. The film formation is controlled so as to have a columnar crystal structure of about 3.0, and the surface roughness of the CrN layer is the maximum height Rz (corresponding international standard ISO4287) specified in ANSI B46.1 (corresponding international standard ISO4287). When the film formation is controlled so that the film formation is 0.5 to 2.5 μm with a simple “surface roughness Rz” (hereinafter, also referred to simply as “surface roughness Rz”), the formed CrN layer has an appropriate anchoring effect and is continuous directly above the CrN layer. It was found that when the hard carbon layer was formed into a film, the adhesion between the CrN layer and the hard carbon layer was very good. It is more preferably 1.0 to 1.6 μm.

As a result, it was found that the following steps required from the conventional formation of the CrN layer to the coating of the hard carbon layer are unnecessary. That is, a step of cooling after forming the CrN layer, opening the furnace to the atmosphere, taking it out of the furnace once, setting it in a polishing device, polishing it, smoothing the CrN layer, and then performing cleaning. After the ring material is loaded into the jig again, vacuuming, raising the temperature, and bombarding the surface, all the steps of coating the hard carbon layer can be eliminated.

Since such a CrN layer has sufficient adhesion to the substrate, a series of continuous hard carbon layers are formed on the CrN layer as they are in the same film forming apparatus. It was found that it can be used as a laminated coating film.

The laminated coating film in which sufficient adhesion is ensured between the CrN layer and the hard carbon layer has the low friction resistance of the hard carbon layer in addition to the wear resistance and peeling resistance of the CrN layer. Since it can be stably exhibited, it is possible to provide a product having a long life and excellent sliding characteristics, for example, a piston ring.

When the CrN layer does not have a columnar crystal structure, sufficient adhesion cannot be ensured between the CrN layer and the hard carbon layer, the hard carbon layer is easily peeled off, and the abrasion resistance of the CrN layer itself is remarkably lowered. ..

Even if the CrN layer has a columnar crystal structure, if the (111) / (200) diffraction intensity ratio is less than 0.50, sufficient adhesion with the hard carbon layer cannot be ensured. The hard carbon layer is easily peeled off. If it exceeds 3.0, the toughness of the CrN layer is impaired and the wear resistance is lowered. It is more preferably 0.65 to 2.60.

Further, when the surface roughness Rz of the CrN layer is less than 0.5 μm, sufficient adhesion cannot be ensured between the CrN layer and the hard carbon layer, and the hard carbon layer is easily peeled off. On the other hand, if it exceeds 2.5 μm, the surface of the hard carbon layer formed on the CrN layer becomes rough, so it is necessary to polish the surface of the hard carbon layer.

Then, as a result of further examination, in the roughness curve, it is also referred to as a load curve [Abbott], which indicates that the deeper the material portion, the more the substance portion increases. ], Which defines the method of determining the parameters using the linear representation of "JIS B 0671-2: Product Geometric Characteristics Specifications (GPS) -Surface Texture: Contour Curve Method; Plateau Structure Surface Characteristic Evaluation-Part 2: Linear" The load length ratio Mr1 in "evaluation of height characteristics by the load curve of expression" has a correlation with the above-mentioned surface roughness Rz, and the numerical range of the load length ratio Mr1 should be specified instead of the surface roughness Rz. It was also found that an appropriate laminated coating film can be provided. The corresponding international standard of JIS B 0671-2 is ISO 13565-2.

As a result, not only the roughness but also the evaluation parameter as the plateau structure surface becomes possible, and it was found that the preferable load length ratio Mr1 is 16 to 35%, and more preferably 17 to 20%.

The inventions according to claims 1 and 2 are based on the above findings, and the invention according to claim 1 is based on the above findings.
A laminated coating film in which a CrN layer is formed as a base layer on a base material and a hard carbon layer is laminated on the CrN layer.
The CrN layer has a columnar crystal structure with an X-ray diffraction intensity ratio (111) / (200) of the (111) plane to the (200) plane of 0.50 to 3.0.
It is a laminated coating film having a surface roughness of 0.5 to 2.5 μm at a maximum height Rz defined in ANSI B46.1.

The invention according to claim 2 is
A laminated coating film in which a CrN layer is formed as a base layer on a base material and a hard carbon layer is laminated on the CrN layer.
The CrN layer has an X-ray diffraction intensity ratio (111) / (200) of the (111) plane to the (200) plane of 0.50 to 3.0, has a columnar crystal structure, and has a columnar crystal structure.
It is a laminated coating film characterized by having a surface of 16 to 35% at a load length ratio Mr1 specified in JIS B 0671-2.

Next, the present inventor conducted experiments and studies on the preferable thickness of the laminated coating film formed on the substrate. As a result, it was found that the CrN layer preferably has a thickness of 3 to 50 μm, and the hard carbon layer preferably has a thickness of 0.5 to 30 μm.

When the thickness of the CrN layer is less than 3 μm, sufficient wear resistance cannot be ensured, and sufficient adhesion to the hard carbon layer cannot be ensured. On the other hand, even if it exceeds 50 μm, sufficient adhesion to the hard carbon layer cannot be ensured. It is more preferably 5 to 40 μm.

By optimizing the surface roughness and thickness of the CrN layer in this way, sufficient adhesion to the hard carbon layer can be ensured, and a series of processes can be performed in the same film forming apparatus without providing a conventional polishing process. Continuous film formation is possible.

Further, when the thickness of the hard carbon layer is less than 0.5 μm, the hard carbon layer is easily peeled off from the CrN layer, and sufficient low friction cannot be ensured. On the other hand, if it exceeds 30 μm, sufficient sliding characteristics cannot be ensured. It is more preferably 1 to 25 μm.

The inventions according to claims 3 and 4 are based on the above findings, and the invention according to claim 3 is based on the above findings.
The laminated coating film according to claim 1 or 2, wherein the CrN layer has a thickness of 3 to 50 μm.

The invention according to claim 4 is
The laminated coating film according to any one of claims 1 to 3, wherein the thickness of the hard carbon layer is 0.5 to 30 μm.

The present inventor further investigated a method for easily confirming the adhesion between the CrN layer and the hard carbon layer, and as a result, a laminated coating film that does not peel off in the Rockwell C scale indentation test is practically necessary. It was found that sufficient adhesion was ensured.

Specifically, using a Rockwell hardness tester, observe the damage state of the laminated coating film generated around the indentation when the diamond indenter (C scale) is pushed from the surface of the laminated coating film toward the base material. At that time, if the laminated coating film is not peeled off, it can be determined that the adhesiveness necessary for practical use is sufficiently secured. In this way, it is possible to easily confirm that the laminated coating film has excellent sliding characteristics only by pushing the diamond indenter and determining the degree of adhesion in the laminated coating film.

That is, the invention according to claim 5 is
The laminated coating film according to any one of claims 1 to 4, wherein the laminated coating film does not peel off in the Rockwell C scale indentation test.

Further studies revealed that the surface roughness Rz of the hard carbon layer is preferably 1.0 μm or less. If the surface roughness Rz exceeds 1.0 μm, high friction may occur between the surface roughness Rz and the sliding partner material, resulting in destruction of the hard carbon layer itself or peeling due to shearing. By setting the thickness to 1.0 μm or less, it is possible to reduce the aggression to the mating material, reduce the coefficient of friction, and prevent the hard carbon layer itself from being destroyed or peeled off by shearing.

Such surface roughness Rz can be obtained, for example, by polishing the surface of the hard carbon layer. Since this polishing process is a step after forming the laminated coating film, it does not hinder the efficient formation of the laminated coating film.

That is, the invention according to claim 6 is
The laminate according to any one of claims 1 to 5, wherein the surface roughness of the hard carbon layer is 1.0 μm or less at the maximum height Rz defined in ANSI B46.1. It is a coating film.

In the present invention, it is further preferable that a second hard carbon layer having a large ^{sp 2} / sp ³ ratio is provided between the CrN layer and the hard carbon layer, that is, at the bottom layer of the hard carbon layer. Specifically, when a ^{second hard carbon layer having a sp 2} / sp ³ ratio of 0.5 to 0.85 is provided at the bottom layer of the hard carbon layer, the second hard carbon layer is used through the second hard carbon layer. The CrN layer, which is the base layer, and the hard carbon layer, which is the upper layer, can be brought into close contact with each other more strongly.

^{When the sp 2} / sp ³ ratio in the second hard carbon layer is less than 0.5, the adhesion is lowered under a high load and may be peeled off from the CrN layer. On the other hand, if it exceeds 0.85, the wear resistance of the hard carbon layer itself is remarkably lowered, and it becomes easy to peel off from the CrN layer. It is more preferably 0.55 to 0.78.

That is, the invention according to claim 7 is
A second hard carbon layer is provided between the CrN layer and the hard carbon layer.
The laminated coating according to any one of claims 1 to 6, wherein the second hard carbon layer is a hard carbon layer having a sp ² / sp ^{3 ratio of 0.5 to 0.85.} It is a cover film.

If a metal intermediate layer such as a Cr layer, a Ti layer, or a W layer is provided between the second hard carbon layer and the CrN layer which is the base layer, the adhesion can be further improved. Is preferable.

That is, the invention according to claim 8 is
The laminated coating film according to claim 7, wherein a metal intermediate layer is provided between the second hard carbon layer and the CrN layer.

Further, the invention according to claim 9 is
The laminated coating film according to claim 8, wherein the metal intermediate layer is at least one layer selected from a Cr layer, a Ti layer, and a W layer.

The laminated coating film in the present invention can be produced by the following method.

That is, the invention according to claim 10 is
On the base material, the intensity ratio (111) / (200) of X-ray diffraction to the (200) plane of the (111) plane is 0.50 to 3.0, and it has a columnar crystal structure and ANSI B46.1. A CrN layer forming step of forming a CrN layer having a surface roughness of 0.5 to 2.5 μm at the maximum height Rz specified in the above as a base layer, and
A hard carbon layer forming step for forming a hard carbon layer is provided on the CrN layer.
Laminated coating characterized in that the CrN layer and the hard carbon layer are laminated by performing the CrN layer forming step and the hard carbon layer forming step as a series of continuous steps in the same film forming apparatus. This is a method for manufacturing a membrane.

Further, the invention according to claim 11
On the base material, the intensity ratio (111) / (200) of X-ray diffraction to the (200) plane of the (111) plane is 0.50 to 3.0, it has a columnar crystal structure, and JIS B 0671- A CrN layer forming step of forming a CrN layer having a surface of 16 to 35% at the load length ratio Mr1 specified in 2 as a base layer, and
A hard carbon layer forming step for forming a hard carbon layer is provided on the CrN layer.
Laminated coating characterized in that the CrN layer and the hard carbon layer are laminated by performing the CrN layer forming step and the hard carbon layer forming step as a series of continuous steps in the same film forming apparatus. This is a method for manufacturing a membrane.

The above-mentioned manufacturing method is different from the conventional manufacturing method of the laminated coating film, which requires two batches for producing the laminated coating film by providing a polishing step between the CrN layer forming step and the hard carbon layer forming step. Since the laminated coating film can be manufactured in a series of continuous processes without being exposed to the atmosphere between the same processing devices, vacuuming, temperature raising, cooling, and opening to the atmosphere, which have been performed after CrN film formation, have been performed so far. -It is possible to process in one batch by omitting the steps of polishing the CrN layer, setting the CrN layer polished base material on the coating jig, loading it into the furnace, vacuuming, and raising the temperature. As a result, low-cost and high-speed film formation becomes possible. Further, since the obtained laminated coating film has improved adhesion, excellent sliding characteristics can be stably maintained for a long period of time.

And the invention according to claim 12
The method for producing a laminated coating film according to claim 10 or 11, wherein the CrN layer has a thickness of 3 to 50 μm.

As described above, by optimizing the surface roughness and thickness of the CrN layer, sufficient adhesion to the hard carbon layer can be ensured, and a series of continuous film formation can be performed in the same film forming apparatus.

Further, the invention according to claim 13 is
The method for producing a laminated coating film according to any one of claims 10 to 12, wherein the thickness of the hard carbon layer is 0.5 to 30 μm.

As described above, by setting the thickness of the hard carbon layer to 0.5 to 30 μm, it is possible to obtain a laminated coating film having sliding characteristics that do not cause any problem in practical use.

Further, the invention according to claim 14
A second hard carbon layer forming step for forming a second hard carbon layer having ^{a sp 2} / sp ³ ratio of 0.5 to 0.85 is provided between the CrN layer forming step and the hard carbon layer forming step. ,
The production of the laminated coating film according to any one of claims 10 to 13, wherein the second hard carbon layer forming step is performed as a series of continuous steps in the same film forming apparatus. The method.

As described above, by providing such a second hard carbon layer between the CrN layer and the hard carbon layer, the CrN layer as the base layer and the upper hard carbon layer can be more strongly adhered to each other.

When the above-mentioned laminated coating film is provided on the piston ring base material, sliding characteristics such as sufficient low friction resistance, wear resistance, and peel resistance can be remarkably improved. It is possible to provide a piston ring having excellent sliding characteristics.

That is, the invention according to claim 15
The piston ring is characterized in that the laminated coating film according to any one of claims 1 to 9 is provided on the base material.

According to the present invention, when the hard carbon layer is coated on the CrN layer, it can be performed in a series of continuous steps in the same film forming apparatus, and moreover, the adhesion of the hard carbon layer to the CrN layer is higher than before. In addition to the wear resistance and peeling resistance of the CrN layer, the low friction property of the hard carbon layer can be stably exhibited to ensure excellent sliding characteristics. It is possible to provide a film forming technique capable of providing the above.

It is a schematic cross-sectional view explaining the laminated coating film which concerns on one Embodiment of this invention. It is a schematic cross-sectional view explaining the modification of the laminated coating film which concerns on one Embodiment of this invention. It is a schematic diagram explaining the main part of the furnace for film formation of the arc type PVD apparatus used for manufacturing the laminated coating film which concerns on one Embodiment of this invention. It is a schematic cross-sectional view explaining the conventional laminated coating film. It is a figure explaining the judgment criteria of the adhesion force in the Rockwell C scale indentation test. It is a figure explaining the friction wear test. It is a figure which shows an example of the load curve and roughness curve obtained in an Example.

Hereinafter, the present invention will be described with reference to the drawings based on the embodiments.

[1] Laminated coating film The laminated coating film according to the present embodiment is
A laminated coating film in which a CrN layer is formed as a base layer on a base material and a hard carbon layer is laminated on the CrN layer.
The CrN layer has an X-ray diffraction intensity ratio (111) / (200) of the (111) plane to the (200) plane of 0.50 to 3.0, has a columnar crystal structure, and has a columnar crystal structure.
It is characterized by having a surface roughness of 0.5 to 2.5 μm at a maximum height Rz defined in ANSI B46.1.

FIG. 1 is a schematic cross-sectional view for explaining the laminated coating film according to the present embodiment, in which 1 is a hard carbon layer, 2 is a base layer, and 3 is a base material.

As shown in FIG. 1, in the laminated coating film according to the present embodiment, a CrN layer is formed as a base layer 2 on the base material 3, and a hard carbon layer 1 is further laminated on the base layer 2. There is.

1. 1. Base material In the present embodiment, the base material on which the coating film is formed is not particularly limited, and in addition to iron-based materials, non-ferrous metals or ceramics, hard composite materials, and other conventionally used materials are used. be able to.

Specific examples thereof include carbon steel, alloy steel, bearing steel, hardened steel, high-speed tool steel, cast iron, aluminum alloy, Mg alloy and cemented carbide. Considering the film formation temperature, it is preferable to use a base material whose characteristics do not significantly deteriorate at a temperature of 250 ° C. or higher.

2. Underlayer A CrN layer is provided as an underlayer 2 on the substrate 3. As described above, the base layer 2 has a (111) / (200) diffraction intensity ratio of 0.50 to 3.0, has a columnar crystal structure, and has a surface roughness Rz of 0.5 to 2.5 μm. have.

This surface roughness Rz of 0.5 to 2.5 μm has an appropriate anchoring effect, but has a level of smoothness that does not require polishing in a post-process as in the conventional case, and therefore has the same film formation. Even if the hard carbon layer 1 is formed on the base layer 2 by a series of continuous film formations in the apparatus, it is hard to secure a stronger adhesion between the base material 3 and the hard carbon layer 1 than before. The carbon layer 1 can be laminated.

As described above, the laminated coating film in which sufficient adhesion is ensured between the CrN layer and the hard carbon layer is formed of the hard carbon layer in addition to the abrasion resistance and peeling resistance of the CrN layer. Since the low friction property can be stably exhibited, it is possible to provide a product having a long life and excellent sliding characteristics, for example, a piston ring.

As described above, when the film formation of the base layer 2 is performed, if the formed CrN layer does not have a columnar crystal structure, the adhesion between the CrN layer and the hard carbon layer is significantly impaired, and the CrN layer itself is further formed. Abrasion resistance is reduced. As a result, it becomes impossible to obtain abrasion resistance and peeling resistance as a laminated coating film, as well as sliding characteristics.

Even if the CrN layer has a columnar crystal structure, if the (111) / (200) diffraction intensity ratio is less than 0.50, sufficient adhesion with the hard carbon layer cannot be ensured, and hard carbon. The layer is easily peeled off. If it exceeds 3.0, the toughness of the CrN layer is impaired and the wear resistance is lowered. It is more preferably 0.65 to 2.60.

Further, when the surface roughness Rz of the CrN layer is less than 0.5 μm, sufficient adhesion cannot be ensured between the CrN layer and the hard carbon layer, and the hard carbon layer is easily peeled off. On the other hand, if it exceeds 2.5 μm, the surface of the hard carbon layer formed on the CrN layer becomes rough, so it is necessary to polish the surface of the hard carbon layer after manufacturing the laminated coating film. , It is not possible to efficiently produce a laminated coating film. It is more preferably 1.0 to 1.6 μm.

In the present embodiment, the thickness of the base layer 2 is preferably 3 to 50 μm. If it is less than 3 μm, sufficient wear resistance cannot be ensured, and sufficient adhesion to the hard carbon layer 1 cannot be ensured. On the other hand, since the thickness of 50 μm is practically and industrially necessary and sufficient, a thickening film exceeding 50 μm unnecessarily increases the burden of manufacturing cost. It is more preferably 20 to 50 μm.

In the above, the surface of the CrN layer has been described using the surface roughness Rz, but as described above, it can also be defined by the load length ratio Mr1, and is preferably 16 to 35%. It is more preferably 17 to 20%.

3. 3. Hard carbon layer In the present embodiment, the hard carbon layer 1 is formed on the base layer 2 as shown in FIG. At this time, as described above, since the CrN layer of the base layer 2 has an appropriate surface roughness Rz or the like, hard carbon is formed on the base layer 2 by a series of continuous film formations in the same film forming apparatus. Even if the layer 1 is formed, it can be laminated while ensuring sufficient adhesion, and in addition to the wear resistance and peeling resistance of the CrN layer, the low frictional property of the hard carbon layer is stably maintained. It is possible to provide a laminated coating film having excellent sliding characteristics by exerting it.

In the present embodiment, the thickness of the hard carbon layer 1 is preferably 0.5 to 30 μm in practical use. That is, as described above, when the thickness is less than 0.5 μm, the hard carbon layer 1 is easily peeled off from the base layer 2 (CrN layer), and sufficient low frictional property cannot be ensured. On the other hand, if it exceeds 30 μm, sufficient sliding characteristics cannot be ensured.

In the present embodiment, the surface roughness Rz of the hard carbon layer 1 is preferably 1.0 μm or less. If it exceeds 1.0 μm, high friction may occur with the sliding mating material, resulting in destruction of the hard carbon layer itself or peeling due to shearing.

In the present embodiment, as shown in FIG. 2, a second hard carbon layer 4 having a ^{sp 2} / sp ^{3 ratio of 0.5 to 0.83 is provided between the CrN layer and the hard carbon layer.} It is preferable that Further, it is more preferable that a metal intermediate layer 5 such as a Cr layer, a Ti layer, and a W layer is provided between the second hard carbon layer 4 and the base layer 2. Note that FIG. 2 is a schematic cross-sectional view illustrating a modified example of such a laminated coating film.

Since the second hard carbon layer 4 is a soft hard carbon layer, the CrN layer which is the base layer 2 and the upper hard carbon layer 1 can be brought into close contact with each other. Further, by providing the metal intermediate layer 5, the adhesion between the CrN layer which is the base layer 2 and the hard carbon layer 1 which is the upper layer can be further improved. The thickness of the second hard carbon layer 4 is preferably 10 to 200 nm, and the thickness of the metal intermediate layer 5 is preferably 20 to 500 nm.

In the above, the sp ² / sp ³ ratio is measured by measuring 1s → π * intensity and 1s → σ * intensity by EELS analysis (Electron Energy-Loss Spectroscopy: electron energy loss spectroscopy), and 1s → π * intensity. Was regarded as sp ² strength, 1s → σ * strength as sp ³ strength, and the ratio of 1s → π * strength and 1s → σ * strength was calculated as ^{sp 2} / sp ^{3 ratio.} Therefore, the sp ² / sp ³ ratio in the present invention accurately refers to the π / σ intensity ratio.

Specifically, the spectrum imaging method in the STEM (scanning TEM) mode is applied, and the EELS obtained at a pitch of 1 nm is integrated under the conditions of an ^{acceleration voltage of 200 kV, a sample absorption current of 10-9 A, and a beam spot size of φ1 nm.} Then, the CK absorption spectrum is extracted as the average information from the region of about 10 nm, and the sp ² / sp ³ ratio is calculated.

4. Laminated coating film The laminated coating film according to the present embodiment has a structure as described above, thereby ensuring the adhesion of the hard carbon layer to the CrN layer more than before, and the abrasion resistance of the CrN layer. In addition to the peeling resistance, the low frictional property of the hard carbon layer can be stably exhibited to ensure excellent sliding characteristics.

Further, when the hard carbon layer is coated on the CrN layer, a laminated coating film can be produced in a series of continuous steps in the same film forming apparatus.

A particularly suitable application of the laminated coating film according to the present embodiment includes a piston ring, but other general applications such as piston pins, gears, bearings, automobile parts such as valve lifters, vanes, and bearings. Mechanical parts can be mentioned.

5. Adhesion Evaluation When evaluating the adhesion between the base material, CrN layer, and hard carbon layer in the manufactured laminated coating film, the Rockwell C scale indentation test can be preferably adopted as a simple adhesion confirmation test.

Specifically, using a Rockwell hardness tester, observe the damage state of the laminated coating film generated around the indentation when the diamond indenter (C scale) is pushed from the surface of the laminated coating film toward the base material. At that time, if the laminated coating film is not peeled off, it can be determined that the adhesiveness necessary for practical use is sufficiently secured. In this way, it is possible to easily confirm that the laminated coating film has excellent sliding characteristics only by pushing the diamond indenter and determining the degree of adhesion in the laminated coating film.

[2] Method for Producing Laminated Coating Film Next, a method for producing the laminated coating film according to the present embodiment will be described.

The method for producing a laminated coating film according to the present embodiment is
On the base material, the intensity ratio (111) / (200) of X-ray diffraction to the (200) plane of the (111) plane is 0.50 to 3.0, and it has a columnar crystal structure and ANSI B46.1. A CrN layer forming step of forming a CrN layer having a surface roughness of 0.5 to 2.5 μm at the maximum height Rz specified in the above as a base layer, and
A hard carbon layer forming step for forming a hard carbon layer is provided on the CrN layer.
The CrN layer and the hard carbon layer are formed by performing the CrN layer forming step and the hard carbon layer forming step as a series of continuous steps in the same film forming apparatus with different raw material types and film forming conditions. It is characterized by laminating.

The laminated coating film according to the present embodiment is produced by using the PVD method, and the arc type PVD method is particularly preferable.

1. 1. Arc-type PVD device First, the arc-type PVD device will be specifically described. FIG. 3 is a diagram schematically showing a main part of a furnace for film formation of the arc type PVD apparatus of the present embodiment. As such an arc type PVD device, for example, an arc type PVD device M720 manufactured by Nippon ITF Co., Ltd. can be mentioned.

As shown in FIG. 3, the arc-type PVD apparatus includes a furnace 11 for film formation and a control device (not shown). The furnace 11 includes a vacuum chamber 6, a plasma generator (not shown), a heater 7, a revolving jig 9 and a rotating jig 10 as a base material support device, and a thermocouple (TC 10 mm) as a thermometer side device. A square bar) 8 and a bias power supply (not shown) and a pressure adjusting device (not shown) for adjusting the pressure in the furnace are provided.

Further, it is preferable that the base material support device or the cooling / heating device for supplying cooling water and / or hot water or steam is provided in the central portion of the furnace. T1 is a chrome target and T2 is a carbon target.

The plasma generator includes an arc power supply, a cathode and an anod, and evaporates chromium or carbon from the cathode material chrome target T1 or carbon target T2 by vacuum arc discharge between the cathode and the anode, and ionizes the cathode material. Generates a plasma containing (chromium ion or carbon ion). The bias power supply applies a predetermined bias voltage to the base material 3 to cause the ionized cathode material to fly to the base material 3 with appropriate kinetic energy.

The revolution jig 9 and the rotation jig 10 are hollow dodecagonal prisms, are rotatable in the direction of the arrow with the center of the furnace body as the center of rotation, and are concentric circles centered on the center of the furnace body. A plurality of rotation axes perpendicular to the upper surfaces of the revolution jig 9 and the rotation jig 10 are provided at equal intervals. Each of the plurality of base materials 3 is held by the rotation axis and is rotatable in the direction of the arrow. As a result, the base material 3 is held by the revolving jig 9 and the revolving jig 10 so as to be revolving and revolving. Further, heat is rapidly conducted between the base material 3, the revolving jig 9, and the revolving jig 10 to the revolving jig 9 and the revolving jig 10, and the base material 3, the revolving jig 9, and the revolving jig 10 are quickly conducted with heat. A metal material having high thermal conductivity such as stainless steel is used so that the temperatures of 10 are substantially equal.

The heater 7 and the cooling heating device (not shown) heat and cool the revolution jig 9 and the rotation jig 10, respectively, whereby the base material 3 is indirectly heated and cooled. Here, the heater 7 is configured so that the temperature can be adjusted. On the other hand, the cooling / heating device is configured so that the supply speed of the cooling / heating medium can be adjusted. Specifically, when cooling is performed, the cooling water is used as jigs 9, 10 and / or the rotating shaft or the center of the furnace. It is configured to supply to the cooling cylinder installed in the unit and stop the supply of cooling water when cooling is stopped, and when heating, hot water or steam is supplied to jigs 9, 10 and / or the rotating shaft to stop heating. Sometimes it is configured to stop the supply of hot water or steam. Further, the thermocouple 8 is attached in the vicinity of the base material 3, and the base material temperature is indirectly measured to change at least one of the arc current value, the bias voltage value, and the heater temperature during film formation. It is configured to control the target substrate temperature.

The control device controls the rotation speeds of the revolution jig 9 and the rotation jig 10 to a predetermined rotation speed so that the base layer and the hard carbon layer are surely formed with the above-mentioned surface roughness Rz. Further, the bias voltage, the arc current, the heater temperature, and the pressure inside the furnace are optimized according to the measurement result of the temperature of the base material 3 by the thermocouple 8. Thereby, the temperature of the base material 3 during the film formation can be controlled to 300 to 400 ° C. in the formation of the base layer and 100 to 350 ° C. in the formation of the hard carbon layer. In addition, the operation of the cooling device and the application pattern of the bias voltage are controlled as necessary.

2. Method for Manufacturing Laminated Coating Film Next, a specific manufacturing method for the laminated coating film using the arc-type PVD apparatus described above will be described.

When the base layer and the hard carbon layer are formed by the arc PVD method, the manufacturing conditions are such that the bias voltage and arc current can be adjusted, the base material can be heated by a heater, and the base material temperature during each film formation can be controlled. To adjust.

(1) Step of Forming Underlayer (CrN Layer) First, a CrN layer to be an underlayer is formed on the base material. Specifically, first, the base material is placed on the rotation jig 10 which is also a base material support device, and then set in the furnace 11 of the arc type PVD device.

Next, with nitrogen gas flowing 500 to 1000 ccm, the pressure in the furnace and / or the substrate temperature is controlled to 300 to 400 ° C. by a thermocouple 8, and the bias voltage -20 V and the arc current are controlled by using the chromium target T1. Under the condition of 150A, a CrN layer is formed on the surface of the base material to a predetermined thickness while rotating the base material at a rotation speed of 10 to 200 rpm and / or revolving at a rotation speed of 1 to 20 rpm. The base material temperature referred to here is the temperature measured by a thermocouple, and the actual base material temperature is the shape (size, length, etc.) of the base material, thermal conductivity, and contact with the jig. Since it is affected by the condition, the heat capacity of the jig, the distance from the thermocouple, etc., there is a slight deviation.

By appropriately adjusting the film forming conditions as described above, the substrate has a (111) / (200) diffraction intensity ratio of 0.50 to 3.0, a columnar crystal structure, and 0. A CrN layer having a surface roughness Rz of 5 to 2.5 μm can be formed as a base layer.

As described above, the formed CrN layer has an appropriate anchoring effect, but has a level of smoothness that does not require polishing in a subsequent process. Therefore, as in the conventional case, the CrN layer has a CrN layer. It is not necessary to once take out the base material on which the carbon dioxide is formed from the arc-type PVD device and perform polishing, and to continuously form a hard carbon layer with sufficient adhesion using the same arc-type PVD device as it is. Can be done.

At this time, since the formed CrN layer has sufficient adhesion to the hard carbon layer, it is hard on the CrN layer with sufficient adhesion in the same film forming apparatus on which the CrN layer is formed. A carbon layer can be laminated.

(2) Formation of hard carbon layer After forming a CrN layer of a predetermined thickness on a substrate, the pressure inside the furnace is controlled and / or the substrate temperature is controlled by a thermocouple 8 as it is in the same arc-type PVD device. While controlling the temperature to 100 to 350 ° C., the carbon target T2 is used to perform arc discharge under the conditions of a bias voltage of -165 V and an arc current of 40 A, and the substrate coated with the CrN layer is rotated at a rotation speed of 10 to 200 rpm. / Or a hard carbon layer is formed on the surface of the CrN layer to a predetermined thickness while revolving at a rotation speed of 1 to 20 rpm.

After forming a hard carbon layer having a predetermined thickness on the CrN layer, the surface of the formed hard carbon layer is polished so that the surface roughness Rz becomes a predetermined value.

[3] Effect of the present embodiment As described above, in the conventional method, the adhesion to the hard carbon layer could not be obtained unless the CrN coating (underlayer) was polished. In the present embodiment, the surface roughness of the underlying layer is optimized by the film forming apparatus, so that the same film forming apparatus is used to form a continuous film with sufficient adhesion when forming the hard carbon layer. It can be carried out.

Then, by continuously forming a laminated coating film of the CrN layer and the hard carbon layer in one batch, the steps of evacuation, temperature rise, cooling, and polishing of the CrN layer, which are required in the conventional two-batch manufacturing method, are omitted. This makes it possible to reduce the cost and speed in the production of the laminated coating film.

Hereinafter, the present invention will be described in more detail based on Examples.

1. 1. Experiment 1
In the following experiments, the surface roughness Rz of the CrN layer and the (111) / (200) diffraction intensity ratio were changed to investigate the relationship between the peel resistance and the abrasion resistance of the hard carbon layer.

(1) Experimental conditions After arranging the steel base material on the rotating jig 10 which is also the base material supporting device, the revolution of the arc type PVD device (arc type PVD device M720 manufactured by Nippon ITF Co., Ltd.) in the furnace 11 Set in the jig 9, the pressure in the furnace and the substrate temperature are controlled by the thermoelectric pair 8 with nitrogen gas flowing 500 to 1000 cm, and the chrome target T1 is used under the conditions of a bias voltage of -20 V and an arc current of 150 A. While rotating (40 rpm) and revolving (4 rpm) the base material, the surface of the base material was coated with 5 μm of a CrN layer having a surface roughness Rz and a (111) / (200) diffraction intensity ratio shown in Table 1. The crystal structures of the formed CrN layers were all columnar crystal structures.

The surface roughness Rz was measured by a method according to ANSI B46.1, in which the base material was taken out from the furnace after the CrN layer was coated with 5 μm. Further, in the laminated coating film of the CrN layer and the hard carbon layer, oxygen plasma is generated in the furnace to sublimate only the hard carbon layer to remove the film, and then the base material is taken out from the furnace to remove the sliding surface. Can also be measured by a method according to ANSI B46.1.

The (111) / (200) diffraction intensity ratio was analyzed by X-ray diffraction, and the crystal structure of the CrN coating was determined by the intensity of X-ray diffraction of the (111) plane with respect to the (200) plane parallel to the surface. ..

After coating with the CrN layer, arc discharge is continuously performed using the carbon target T2 under the conditions of a bias voltage of 165 V and an arc current of 40 A without exposure to the atmosphere, and the substrate is rotated (40 rpm) and revolved (4 rpm). The hard carbon layer of 1.0 μm was coated, and the surface of the hard carbon layer was polished to Rz of 1.0 μm or less.

(2) Evaluation (a) Peeling resistance (adhesion)
For the amorphous hard carbon layer, the obtained test piece was subjected to a Rockwell C scale indentation test (indenter: diamond cone with tip radius 0.2 ± 0.2 mm and tip angle 120 ° ± 30', pressing load: 1470N ( Perform at 3 to 5 points using 150 kgf)), observe the state of the coating film around the indentation with a microscope at a magnification of 100 times or more, and determine the adhesion according to the criteria of H1 to H5 shown in FIG. It was measured and the peel resistance was evaluated. The specific contents of H1 to H5 are as follows.
H1: No peeling H2: Micro peeling at the boundary H3: Peeling that does not reach the entire circumference H4: Peeling on the entire circumference However, the peeling range is within 0.2 mm from the edge H5: Peeling on the entire circumference The peeling range is 0. Over 2 mm

In the evaluation of the peeling resistance, it was determined that the adhesion was excellent if it was H1, good if it was H2 or H3, and not possible if it was H4 or H5. If it is excellent or good, peeling that is a problem in practical use does not occur.

(B) Abrasion resistance Amorphous hard carbon layer is rubbed with the obtained test piece using an SRV (Schwingungs Reihungund Verschles) tester, which is generally used in the evaluation of sliding members for automobiles. A test was conducted and the wear resistance was evaluated according to the following criteria. If the evaluation is excellent and good, it can be judged that there is no practical problem.

Specifically, as shown in FIG. 6, in a state where the sliding surface of the friction and wear test sample W is in contact with the SUJ2 material 24 to be slid, 5W-30 (without Mo-DTC) is applied to the lubricating oil. While applying a load of 100 to 300 N, the sample W was slid back and forth for 10 minutes, and the sliding surface of the friction and wear test sample W was observed with a microscope. Then, from the observation result, the presence or absence of peeling of the sliding marks and the amount of wear were measured. As for the amount of wear, a stylus type step meter was used to determine the amount of step between the non-sliding portion and the sliding portion as the total amount of wear. In FIG. 6, 21 is a base material, 22 is a base layer, and 23 is a hard carbon layer.

Excellent: The total amount of wear is within 1/4 of the total film thickness, and the wear resistance is excellent.
Good: The total amount of wear exceeds 1/4 of the total film thickness and is within 1/2, and the wear resistance is good.
Possible: The total amount of wear is more than 1/2 of the total film thickness and within the total film thickness, and it cannot be said that the wear resistance is inferior.
Impossible: The base is exposed, the total amount of wear exceeds the total film thickness, and the wear resistance is inferior.

(C) Evaluation results Table 1 summarizes the evaluation results.

From Table 1, when the (111) / (200) diffraction intensity ratio is 0.50 or more and 3.0 or less and the surface roughness Rz of the CrN layer is 0.5 to 2.5 (Experimental Examples 12 to 20, It was confirmed that high peel resistance and abrasion resistance of the amorphous hard carbon layer could be obtained in Experimental Examples 24 to 32, Experimental Examples 36 to 44, and Experimental Examples 48 to 54). Further, when the (111) / (200) diffraction intensity ratio is 0.65 or more and 3.0 or less (Experimental Examples 26 to 32, Experimental Examples 38 to 44), even higher peeling resistance and abrasion resistance can be obtained. I was able to confirm that.

2. Experiment 2
In the following experiments, the thickness of the CrN layer was changed, and the relationship between the peel resistance and the abrasion resistance of the hard carbon layer was investigated.

(1) Experimental conditions A laminated coating film was prepared in the same manner as in Experiment 1. However, the surface roughness Rz of the CrN layer was fixed at 1.0 μm, and the (111) / (200) diffraction intensity ratio of the CrN layer was fixed at 1. The thickness of the hard carbon layer was 1.0 μm, and the surface of the hard carbon layer was polished to Rz 1.0 μm or less.

(2) Evaluation (a) Peeling resistance (adhesion)
The same Rockell C scale indentation test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(B) Abrasion resistance The same friction test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(C) Evaluation results Table 2 summarizes the evaluation results.

From Table 2, it was found that a sufficiently practical laminated coating film was obtained in all the experimental examples (experimental examples 58 to 64). Further, it was confirmed that further high peelability and wear resistance can be obtained especially when the thickness of the CrN layer is 3 to 50 μm (Experimental Examples 59 to 63).

3. 3. Experiment 3
In the following experiments, the surface roughness Rz of the CrN layer was changed, the corresponding Mr1 was measured, and the relationship between the peel resistance and the wear resistance of the hard carbon layer was investigated.

(1) Experimental conditions A laminated coating film was prepared in the same manner as in Experiment 1. However, the (111) / (200) diffraction intensity ratio of the CrN layer was fixed at 1.0. The thickness of the CrN layer was 5 μm, and the thickness of the hard carbon layer was 1.5 μm. The surface of the hard carbon layer was polished to Rz of 1.0 μm or less.

(2) Evaluation (a) Peeling resistance (adhesion)
The same Rockell C scale indentation test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(B) Abrasion resistance The same friction test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(C) Evaluation results Table 3 summarizes the evaluation results.

From Table 3, it was confirmed that when the load length ratio Mr1 was 16 to 35% (Experimental Example 70, Experimental Example 72 to 85), sufficiently practical peeling resistance and wear resistance could be obtained. Then, it can be seen from Table 3 that the load length ratio Mr1 of 16 to 35% correlates with the surface roughness Rz of 0.5 to 2.5 μm.

The load curve and roughness curve obtained in Experimental Example 68 and Experimental Example 80 are shown in FIGS. 7 (a) and 7 (b), respectively.

4. Experiment 4
In the following experiments, the relationship between the peel resistance and abrasion resistance of the hard carbon layer was investigated by changing the thickness of the hard carbon layer.

(1) Experimental conditions A laminated coating film was prepared in the same manner as in Experiment 1. However, the surface roughness Rz of the CrN layer was fixed at 1.0 μm, and the (111) / (200) diffraction intensity ratio of the CrN layer was fixed at 1. The thickness of the CrN layer was set to 20 μm, and the surface of the hard carbon layer was polished to Rz of 1.0 μm or less.

(2) Evaluation (a) Peeling resistance (adhesion)
The same Rockell C scale indentation test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(B) Abrasion resistance The same friction test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(C) Evaluation results Table 4 summarizes the evaluation results.

From Table 4, it was found that a sufficiently practical laminated coating film was obtained in all the experimental examples (Experimental Examples 86 to 92). Further, it was confirmed that further high peelability and wear resistance can be obtained especially when the thickness of the hard carbon layer is 0.5 to 30 μm (Experimental Examples 87 to 91).

5. Experiment 5
In the following experiment, a second hard carbon layer is provided between the CrN layer and the hard carbon layer, and the sp ² / sp ³ ratio of the second hard carbon layer is changed to obtain the peel resistance of the hard carbon layer and the peel resistance of the hard carbon layer. The relationship with wear resistance was investigated.

(1) Experimental conditions The experimental conditions were basically the same as in Experiment 1, and a laminated coating film was prepared. However, after the CrN layer was formed, the second hard carbon layer was formed, and then the temperature was cooled to the same temperature as that of Experiment 1 to form the hard carbon layer on the second hard carbon layer. The surface roughness Rz of the CrN layer was fixed at 1.0 μm, and the (111) / (200) diffraction intensity ratio of the CrN layer was fixed at 1. The thickness of the CrN layer was 20 μm, the thickness of the hard carbon layer was 1 μm, the surface of the hard carbon layer was polished to Rz 1.0 μm or less, and the thickness of the second hard carbon layer was 40 nm.

(2) Evaluation (a) Peeling resistance (adhesion)
The same Rockwell C scale indentation test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(B) Abrasion resistance The same friction test as in Experiment 1 was performed. In addition, the same judgment criteria as in Experiment 1 were adopted as the judgment criteria.

(C) Evaluation results Table 5 summarizes the evaluation results.

From Table 5, it was found that a sufficiently practical laminated coating film was obtained in all the experimental examples (Experimental Examples 93 to 98). Further, it was confirmed that further high peelability and wear resistance can be obtained especially when the sp ² / sp ^{3 ratio of the second hard carbon layer is 0.5 to 0.83 (Experimental Examples 94 to 97).} ..

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. Within the same and equal scope as the present invention, various modifications can be made to the above embodiments.

1,23 Hard carbon layer 2,22 Base layer 3,21 Base material 4 Second hard carbon layer 5 Metal intermediate layer 6 Vacuum chamber 7 Heater 8 Thermocouple 9 Revolution jig 10 Rotation jig 11 Furnace 24 SUJ2 material T1 Chrome Target T2 Carbon target W Friction wear test sample

Claims (15)

A laminated coating film in which a CrN layer is formed as a base layer on a base material and a hard carbon layer is laminated on the CrN layer.
The CrN layer has an X-ray diffraction intensity ratio (111) / (200) of the (111) plane to the (200) plane of 0.50 to 3.0, has a columnar crystal structure, and has a columnar crystal structure.
A laminated coating film having a surface roughness of 0.5 to 2.5 μm at a maximum height Rz defined in ANSI B46.1. A laminated coating film in which a CrN layer is formed as a base layer on a base material and a hard carbon layer is laminated on the CrN layer.
The CrN layer has a columnar crystal structure with an X-ray diffraction intensity ratio (111) / (200) of the (111) plane to the (200) plane of 0.50 to 3.0.
A laminated coating film having a surface of 16 to 35% at a load length ratio Mr1 specified in JIS B 0671-2. The laminated coating film according to claim 1 or 2, wherein the CrN layer has a thickness of 3 to 50 μm. The laminated coating film according to any one of claims 1 to 3, wherein the thickness of the hard carbon layer is 0.5 to 30 μm. The laminated coating film according to any one of claims 1 to 4, wherein the laminated coating film does not peel off in the Rockwell C scale indentation test. The laminate according to any one of claims 1 to 5, wherein the surface roughness of the hard carbon layer is 1.0 μm or less at the maximum height Rz defined in ANSI B46.1. Coating film. A second hard carbon layer is provided between the CrN layer and the hard carbon layer.
The laminated coating according to any one of claims 1 to 6, wherein the second hard carbon layer is a hard carbon layer having a sp ² / sp ^{3 ratio of 0.5 to 0.85.} Cover film. The laminated coating film according to claim 7, wherein a metal intermediate layer is provided between the second hard carbon layer and the CrN layer. The laminated coating film according to claim 8, wherein the metal intermediate layer is at least one layer selected from a Cr layer, a Ti layer, and a W layer. On the base material, the intensity ratio (111) / (200) of X-ray diffraction to the (200) plane of the (111) plane is 0.50 to 3.0, and it has a columnar crystal structure and ANSI B46.1. A CrN layer forming step of forming a CrN layer having a surface roughness of 0.5 to 2.5 μm at the maximum height Rz specified in the above as a base layer, and
A hard carbon layer forming step for forming a hard carbon layer is provided on the CrN layer.
Laminated coating characterized in that the CrN layer and the hard carbon layer are laminated by performing the CrN layer forming step and the hard carbon layer forming step as a series of continuous steps in the same film forming apparatus. Membrane manufacturing method. On the base material, the intensity ratio (111) / (200) of X-ray diffraction to the (200) plane of the (111) plane is 0.50 to 3.0, it has a columnar crystal structure, and JIS B 0671- A CrN layer forming step of forming a CrN layer having a surface of 16 to 35% at the load length ratio Mr1 specified in 2 as a base layer, and
A hard carbon layer forming step for forming a hard carbon layer is provided on the CrN layer.
Laminated coating characterized in that the CrN layer and the hard carbon layer are laminated by performing the CrN layer forming step and the hard carbon layer forming step as a series of continuous steps in the same film forming apparatus. Membrane manufacturing method. The method for producing a laminated coating film according to claim 10 or 11, wherein the CrN layer has a thickness of 3 to 50 μm. The method for producing a laminated coating film according to any one of claims 10 to 12, wherein the thickness of the hard carbon layer is 0.5 to 30 μm. A second hard carbon layer forming step for forming a second hard carbon layer having ^{a sp 2} / sp ³ ratio of 0.5 to 0.85 is provided between the CrN layer forming step and the hard carbon layer forming step. ,
The production of the laminated coating film according to any one of claims 10 to 13, wherein the second hard carbon layer forming step is performed as a series of continuous steps in the same film forming apparatus. Method. A piston ring characterized in that the laminated coating film according to any one of claims 1 to 9 is provided on a base material.