JP2022099051A - Slide member and method for manufacturing the same - Google Patents

Abstract

To obtain a slide member excellent in smoothness.SOLUTION: A slide member (10) includes a base material (1) and a coating covering the surface of the base material (1) sliding at least an opposite material. The coating includes a first amorphous carbon layer (4) and a second amorphous carbon layer (5); the first amorphous carbon layer (4) is formed between the base material (1) and the second amorphous carbon layer (5); the first amorphous carbon layer (4) has a hardness higher than that of the second amorphous carbon layer (5); and in the cross section of the coating, the density of an abnormal growth material (7) using a macro particle (P) existing in the first amorphous carbon layer (4) as a nucleus is 11.8×10-3 pieces/μm2 or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sliding member and a method for manufacturing the sliding member. Here, the sliding member is a member that constitutes a sliding portion that slides while relatively rubbing against each other, such as a shaft and a bearing. Further, the sliding portion is generally used for a driving portion of a mechanical device.

Friction occurs when the sliding part is slid. Due to the friction, there is a problem that the durability and accuracy of the sliding member constituting the sliding portion are lowered.

As a method for solving the above problem, a method of covering the sliding surface of the sliding member with an amorphous carbon film is known.

As an example of the sliding member whose sliding surface is covered with the above-mentioned amorphous carbon film, for example, the hard material which is an amorphous carbon film on at least the outer peripheral sliding surface of the base material described in Patent Document 1. The hard carbon film has a structure in which a carbon film is formed, and the ^sp2 component ratio is in the range of 40% or more and 80% or less, and the hydrogen content is 0.1 atomic% or more and 5 atomic% or less. Examples thereof include a piston ring, which is within the range and the amount of macroparticles appearing on the surface is within the range of 0.1% or more and 10% or less in terms of area ratio. The sp ² component ratio means the ratio of the number of sp ² bonds to the total of sp ² bonds and sp ³ bonds in the carbon (C) constituting the hard carbon film.

Further, as a sliding member having improved adhesion between the amorphous carbon film and the base material in the sliding member, the sliding member described in Patent Document 2 is directed from the inner surface side to the outer surface side, which is the base material (base material) side. It has an inclined structure in which the sp ² ratio increases in accordance with, and the sp ² ratio on the inner surface side of the amorphous hard carbon film: A% and the sp ² ratio on the outer surface side of the amorphous hard carbon film: Examples thereof include sliding members having a relationship of (BA) ≧ 20 with B%. Here, the sp ² ratio means the ratio of the number of sp ² bonds to the total of sp ² bonds and sp ³ bonds in the carbon (C) constituting the amorphous hard carbon film.

International Publication 2015/11601 Pamphlet Japanese Patent No. 6357606

However, the sliding member whose sliding surface is covered with the conventional amorphous carbon film as described above has a large surface roughness and smoothness, especially when the amorphous carbon film is thickened. There was a problem that it got worse.

An object of the present invention is to solve the above-mentioned problems and to obtain a sliding member having a small surface roughness and excellent smoothness even when the amorphous carbon film is thickened.

The present invention includes the inventions shown in the following [1] to [6].

[1] A sliding member including a base material and a coating film covering at least a surface of the base material that slides on the mating material.
The coating comprises a first amorphous carbon layer and a second amorphous carbon layer.
The first amorphous carbon layer is formed between the base material and the second amorphous carbon layer.
The first amorphous carbon layer has a higher hardness than the second amorphous carbon layer.
In the cross section of the coating film, the density of abnormal growth products having macroparticles as nuclei existing in the first amorphous carbon layer is 11.8 × 10 ^-3 / μm ² or less. Sliding member.

[2] The first amorphous carbon layer has a layer thickness of 100 nm or more, and is characterized in that it is 1000 nm or less, which is thicker than 20% of the total film thickness of the coating film. , [1].

[3] The sliding member according to [1] or [2], wherein the hardness of the first amorphous carbon layer is 40 GPa or more and 80 GPa or less.

[4] The ID / IG value of the first amorphous carbon layer obtained by Raman spectroscopy is 1.0 or less, and the G peak shift is 1535 cm ^-1 or more and 1570 cm ^-1 or less. The sliding member according to any one of [1] to [3].

[5] The total thickness of the first amorphous carbon layer and the thickness of the second amorphous carbon layer is 1 μm or more and 50 μm or less [1]. The sliding member according to any one of [4].

[6] The method for manufacturing the sliding member according to any one of [1] to [5].
A step of forming the first amorphous carbon layer on the substrate by using a physical vapor deposition method is included.
A method for manufacturing a sliding member, which comprises controlling the maximum temperature reached of the base material to 150 ° C. or lower in the step of forming the first amorphous carbon layer.

The sliding member according to the embodiment of the present invention has an effect of being excellent in smoothness.

It is a schematic diagram which shows the structure of the sliding member which was covered with the film | coating which consists of the conventional first amorphous carbon layer and the second amorphous carbon layer. It is a schematic diagram which shows the structure of the sliding member which concerns on one Embodiment of this invention.

An embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications can be made within the scope of the claims, and the technical means disclosed in the different embodiments may be appropriately combined. The obtained embodiments are also included in the technical scope of the present invention. Unless otherwise specified in the present specification, "A to B" representing a numerical range means "A or more and B or less".

[Embodiment 1: Sliding member]
The sliding member according to the first embodiment of the present invention is a sliding member including a base material and a coating film that covers at least a surface of the base material that slides on the mating material, and the coating film is the first. The first amorphous carbon layer is formed between the base material and the second amorphous carbon layer, and includes the amorphous carbon layer and the second amorphous carbon layer. The first amorphous carbon layer has a higher hardness than the second amorphous carbon layer, and in the cross section of the coating film, the macroparticles existing in the first amorphous carbon layer are used as nuclei. It is characterized in that the density of the abnormal growth product is 11.8 × 10 ^-3 pieces / μm ² or less.

[Base material]

As the base material according to the embodiment of the present invention, a material suitable for the application of the sliding member according to the embodiment of the present invention may be selected. For example, when the sliding member according to the embodiment of the present invention is used for manufacturing any of a piston ring, a piston pin and a compressor, various steel materials and stainless steel materials can be used as a base material in the vibrating member. , A base material generally used as a base material for a piston ring, a piston pin and a compressor, such as a casting material and a cast steel material.

The substrate in one embodiment of the invention may optionally be pretreated before being coated with a coating. Examples of the pretreatment include adjusting the surface roughness by surface polishing, cleaning the surface with a cleaning agent, plasma, and the like.

Further, an intermediate layer may be formed between the base material and the coating film. The intermediate layer is a layer for improving the adhesion between the base material and the coating film, which has lattice consistency with the metal constituting the base material and is the first amorphous layer than the metal. Examples thereof include a layer composed of a metal element or a metal carbide thereof, which easily forms carbon and carbide in the carbon layer. The metal element is specifically selected from the group consisting of titanium (Ti), chromium (Cr), silicon (Si), cobalt (Co), vanadium (V), molybdenum (Mo) and tungsten (W). At least one metal element.

The layer thickness of the intermediate layer is not particularly limited, and is, for example, preferably 0.01 μm or more, more preferably 0.03 μm or more, still more preferably 0.05 μm or more, and 0.1 μm. The above is particularly preferable. It is preferable that the layer thickness of the intermediate layer is equal to or more than the above-mentioned value in that the adhesiveness between the base material and the coating film can be suitably improved by the intermediate layer. On the other hand, when the intermediate layer is excessively thick, it is considered that the deformation of the intermediate layer adversely affects the adhesion between the base material and the coating film. Therefore, from the viewpoint of preventing the above-mentioned adverse effects, the layer thickness of the intermediate layer is, for example, preferably 5 μm or less, more preferably 0.4 μm or less, and more preferably 0.3 μm or less. It is more preferably 0.2 μm or less, and particularly preferably 0.2 μm or less.

In the following, when the intermediate layer is formed, a member composed of the base material and the intermediate layer is also included in the "base material".

[Film]
The coating film in one embodiment of the present invention covers at least the surface of the base material that slides on the mating material, and includes a first amorphous carbon layer described later and a second amorphous carbon layer described later. .. Further, the coating film in one embodiment of the present invention preferably comprises a first amorphous carbon layer described later and a second amorphous carbon layer described later.

(First amorphous carbon layer)
The first amorphous carbon layer in one embodiment of the present invention is formed between the base material and the second amorphous carbon layer, and is preferably formed directly on the base material.

In the cross section of the coating film, the sliding member according to the embodiment of the present invention has a density of abnormal growth substances having macroparticles as nuclei present in the first amorphous carbon layer, in other words, the first. The density of macroparticles that are the core of abnormal growth substances existing in the amorphous carbon layer of 11.8 × 10 ^-3 / μm ² or less is 1.5 × 10 ^-3 / μm ² . The following is preferable.

In a coating film containing an amorphous carbon layer on the substrate side, such as the coating film in one embodiment of the present invention, the amorphous carbon layer is formed with macroparticles existing in the amorphous carbon layer as nuclei. The heat of time produces cone-shaped amorphous products. FIG. 1 is a cross-sectional view schematically showing the configuration of the conventional sliding member 10'. FIG. 2 is a cross-sectional view schematically showing the configuration of the sliding member 10 according to the present embodiment.

Here, as shown in FIG. 1, the conventional sliding member 10'has a base material 1, a first amorphous carbon layer 2, and a second amorphous carbon layer 3. The coating film of the sliding member 10'has at least a laminated structure including a first amorphous carbon layer 2 and a second amorphous carbon layer 3. The first amorphous carbon layer 2 is formed on the base material 1 side, and the second amorphous carbon layer 3 is formed on the side opposite to the base material 1 in the first amorphous carbon layer 2. Has been done. When the amorphous carbon layer is formed in the film by the vacuum arc vapor deposition method, the hard carbon macroparticles P are present in the first amorphous carbon layer 2. Then, the abnormal growth product 7 is generated with the macro particle P as the nucleus. The abnormal growth product 7 grows at the time of film formation of the first amorphous carbon layer 2, that is, from the initial stage of film formation. Then, the abnormal growth product 7 expands in a cone shape as it grows, and appears as a raised morphology on the outermost surface 6 of the coating film. In the conventional sliding member 10', the abnormal growth product 7 grows from the initial stage of film formation. Therefore, as the film thickness of the second amorphous carbon layer 3 increases, the abnormal growth product 7 with respect to the outermost surface 6 It rises greatly. As a result, in the conventional sliding member 10', the surface roughness increases as the film thickness of the second amorphous carbon layer 3 increases.

On the other hand, as shown in FIG. 2, the coating film in the sliding member 10 according to the embodiment of the present invention is a laminate composed of a first amorphous carbon layer 4 and a second amorphous carbon layer 5. Has a structure. The first amorphous carbon layer 4 is formed on the base material 1 side, and the second amorphous carbon layer 5 is formed on the side opposite to the base material 1 in the first amorphous carbon layer 4. Has been done. According to the sliding member 10 according to the embodiment of the present invention, in the coating film, the density of the hard carbon macroparticles P is 11.8 × 10 ^-3 in the first amorphous carbon layer 4. It is less than / μm ² or does not exist. The microparticles P are mainly present in the second amorphous carbon layer 5. Therefore, in the sliding member 10 according to the embodiment of the present invention, the abnormal growth product 7 grows from the time when the second amorphous carbon layer 5 is formed. Since the abnormal growth product 7 has not grown from the initial stage of film formation, the raised morphology appearing on the outermost surface 6 of the coating film does not rise significantly as compared with the conventional sliding member 10'. As a result, the sliding member 10 according to the embodiment of the present invention has a small surface roughness and is excellent in smoothness.

The method for measuring the density of the abnormal growth product having macroparticles as nuclei existing in the first amorphous carbon layer is not particularly limited, and examples thereof include the following methods. First, an arbitrary cross section obtained by cutting the sliding member in a direction perpendicular to the surface of the base material is observed using a scanning electron microscope (SEM) in the first amorphous carbon layer. The number of abnormal growth products having a starting point is measured. Then, the measured number of abnormal growth products is divided by the product of the evaluation length of SEM and the layer thickness of the first amorphous carbon layer, and the macro present in the first amorphous carbon layer is divided. Calculate the density of amorphous growth with particles as nuclei.

Examples of the method for controlling the density of abnormal growth substances having macroparticles as nuclei in the first amorphous carbon layer include the following methods. That is, the highest of the base material when forming the first amorphous carbon layer by using the physical vapor deposition method as in the method for manufacturing a sliding member according to the second embodiment of the present invention described later. A method of controlling the ultimate temperature within a specific range can be mentioned.

However, the density of the abnormal growth material having macroparticles as nuclei existing in the first amorphous carbon layer is only the maximum temperature reached by the base material when forming the first amorphous carbon layer. It does not depend on the above, but also varies depending on the time for forming the first amorphous carbon layer and the like. Here, as a method of forming the first amorphous carbon layer by using the physical vapor deposition method, a discharge is generated between the amorphous carbon source and the base material, and the ionized carbon is used. The method of spraying on the substrate is common. Immediately after the formation of the first amorphous carbon layer by the above-mentioned method is started, the discharge is difficult to stabilize, and macroparticles which are the cores of the abnormal growth product are likely to be generated. On the other hand, as time elapses in the formation of the first amorphous carbon layer, the discharge is stabilized, and as a result, the generation of macroparticles which are the cores of the abnormal growth product is suppressed. Therefore, by controlling the time for forming the first amorphous carbon layer to such a time that the discharge is stabilized, the generation of macroparticles that are the cores of the abnormal growth product is suppressed, and as a result. , The density of abnormal growth products having macroparticles as nuclei existing in the first amorphous carbon layer can be controlled. Generally, the longer the time for forming the first amorphous carbon layer, the larger the layer thickness of the first amorphous carbon layer to be produced. Further, when the first amorphous carbon layer is formed by using the physical vapor deposition method under the same conditions, the large thickness of the first amorphous carbon layer means that the thickness of the first amorphous carbon layer is large. It also means that the formation time of the first amorphous carbon layer is long. Therefore, when the first amorphous carbon layer is formed by the physical vapor deposition method under the same conditions, the larger the layer thickness of the first amorphous carbon layer, the more. It is considered that the density of the abnormal growth product in the first amorphous carbon layer becomes small. Specifically, the first amorphous carbon layer can be formed with the layer thickness within a preferable range described later under normal conditions for the time for forming the first amorphous carbon layer. It is preferable to control the time to a certain degree.

The first amorphous carbon layer in one embodiment of the present invention has a higher hardness than the second amorphous carbon layer described later. As used herein, hardness represents the indentation hardness that can be measured when a diamond indenter is indented into an object. Further, the hardness can be measured by, for example, the method of nano indenter.

The specific hardness of the first amorphous carbon layer in one embodiment of the present invention is preferably 40 GPa or more and 80 GPa or less, and more preferably 55 GPa or more and 80 GPa or less.

The layer thickness of the first amorphous carbon layer in one embodiment of the present invention is 100 nm or more, which is 1000 nm or less than 20% of the total film thickness of the coating film. It is preferably 500 nm or more, and more preferably 1000 nm and 20% or less of the total film thickness of the coating, which is thicker than the layer thickness. The method for measuring the layer thickness of the first amorphous carbon layer is not particularly limited, and for example, an arbitrary cross section obtained by cutting the sliding member in a direction perpendicular to the surface of the base material. Can be mentioned as a method of measuring by observing with SEM. Further, when the hardness of the first amorphous carbon layer is relatively low, it may be difficult to distinguish the first amorphous carbon layer from the second amorphous carbon layer by SEM. Therefore, in that case, it is preferable to measure the layer thickness of the first amorphous carbon layer by also performing the layer thickness measurement by the carotest method.

In one embodiment of the present invention, when the layer thickness of the first amorphous carbon layer is 100 nm or more, the size of the raised morphology in which the abnormal growth appears on the outermost surface of the sliding member is increased. It can be made smaller to more preferably improve the smoothness of the sliding member. Further, in one embodiment of the present invention, the hardness of the first amorphous carbon layer is less than or equal to 1000 nm, which is thicker than 20% of the total thickness of the coating film. It is preferable that the proportion of the first amorphous carbon layer having a higher value in the coating film increases, so that the internal stress in the coating film increases, and as a result, the coating film peels off from the sliding member. Can be prevented.

In one embodiment of the present invention, the ID / IG value of the first amorphous carbon layer by Raman spectroscopy is preferably 1.0 or less, and preferably 0.9 or less. Further, in one embodiment of the present invention, the G peak shift of the first amorphous carbon layer by Raman spectroscopy is preferably 1535 cm ^-1 or more and 1570 cm ^-1 or less, and 1550 cm ^-1 or more ^and 1570 cm-. It is more preferably ¹ or less.

Here, the Raman spectrum obtained by Raman spectroscopy of the amorphous carbon layer has a D peak near the wave number 1350 cm ^-1 and a G peak near the wave number 1550 cm ^-1 . The ID is the peak area of the D peak. The IG is the peak area of the G peak. The value of the G peak shift is the wave number of the peak position at the G peak.

Examples of the method for measuring the ID / IG value and the G peak shift include the methods shown in the following (1) to (3).

(1) A Raman spectrum is obtained by measuring the first amorphous carbon layer with a commercially available Raman spectrophotometer.

(2) Raman spectrum obtained The baseline is removed from the Raman spectrum by a straight line, and then peak separation is performed on the D peak and the G peak.

(3) The peak areas of the D peak and the G peak separated from the peak, and the peak position of the G peak are measured, and the peak area ratio ID / IG value and the G peak shift are measured based on the measured values. Calculate the value.

(Second amorphous carbon layer)
The second amorphous carbon layer in one embodiment of the present invention is formed at a position farther from the base material than the first amorphous carbon layer.

The second amorphous carbon layer in one embodiment of the present invention has a lower hardness than the first amorphous carbon layer. The second amorphous carbon layer preferably constitutes the outermost surface of the sliding member. The outermost surface is a portion of the sliding portion composed of the sliding member that comes into contact with other members. Therefore, due to the low hardness of the second amorphous carbon layer, particularly when the film is thickened, the thick film provides wear resistance to contact and rubbing with the other members. It is improved and the hardness is low, so that the opponent's aggression against the other member is lowered. Further, the low hardness of the second amorphous carbon layer improves the polishability and the throughput of the sliding member.

The specific hardness of the second amorphous carbon layer in one embodiment of the present invention is preferably 10 GPa or more and less than 40 GPa, and more preferably 20 GPa or more and 38 GPa or less.

The layer thickness of the second amorphous carbon layer in one embodiment of the present invention is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.5 μm or more and 30 μm or less. Further, in relation to the total film thickness of the coating film, the layer thickness of the second amorphous carbon layer in one embodiment of the present invention is preferably 60% or more of the total film thickness of the coating film. The method for measuring the layer thickness of the second amorphous carbon layer is not particularly limited, and for example, the sliding member is used in the same manner as the method for measuring the layer thickness of the first amorphous carbon layer. A method of measuring by observing an arbitrary cross section obtained by cutting in a direction perpendicular to the surface of the base material with SEM can be mentioned. Further, when the hardness of the first amorphous carbon layer is relatively low, the first amorphous carbon layer is measured by SEM as in the method of measuring the layer thickness of the first amorphous carbon layer. And the second amorphous carbon layer may be difficult to distinguish. In that case, the layer thickness of the second amorphous carbon layer can be measured by measuring the layer thickness by the carotest method. It is preferable to measure.

In one embodiment of the present invention, it is preferable that the layer thickness of the second amorphous carbon layer is 0.1 nm or more in terms of preferably reducing the aggression against the other members. Further, in one embodiment of the present invention, the layer thickness of the second amorphous carbon layer being 50 nm or less prevents the sliding member from becoming excessively large and difficult to incorporate into a mechanical device or the like. It is preferable in terms of being able to do it. Further, the fact that the layer thickness of the second amorphous carbon layer is 60% or more of the film thickness means that, in addition to the surface that suitably reduces the aggression against the other member, the layer thickness of the second amorphous carbon layer is higher than that of the other member. It is more preferable in terms of preferably improving the wear resistance against contact and rubbing.

(Other layers)
The coating film in one embodiment of the present invention may include a layer other than the first amorphous carbon layer and the second amorphous carbon layer.

Examples of the other layer include another amorphous carbon layer formed between the first amorphous carbon layer and the second amorphous carbon layer, and the second non-amorphous carbon layer. Crystalline carbon layer Examples thereof include the wear-resistant surface treatment layer formed above.

The layer thickness of the other layers is not particularly limited as long as the effect of the present invention is not impaired, and is preferably 20% or less of the total film thickness of the coating film, which is 10 of the total film thickness of the coating film. % Or less is more preferable.

(Physical characteristics of the film)
The film thickness according to the embodiment of the present invention is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 30 μm or less, and further preferably 5 μm or more and 30 μm or less.

In one embodiment of the present invention, when the film thickness of the coating film is 1 μm or more, the film thickness of the coating film functioning as a protective film is sufficiently large to withstand contact and rubbing with the other members. It is preferable in that the wear resistance can be suitably improved and the opponent's aggression against the other member can be suitably reduced. In one embodiment of the present invention, it is preferable that the film thickness of the coating film is 30 μm or less in that the sliding member can be prevented from becoming excessively large and difficult to be incorporated into a mechanical device or the like.

In one embodiment of the present invention, the density of the abnormal growth material having macroparticles as nuclei in the coating film is preferably 30 × 10 ^-3 / μm ² or less, and 25 × 10 ^-3 / μm 2. It is more preferably μm ² or less.

In one embodiment of the present invention, the density of the abnormal growth substance defining the macroparticles existing in the coating film is within the above range, which may be a factor for deteriorating the smoothness of the sliding member. As a result, the smoothness of the sliding member is preferably improved.

[Embodiment 2: Manufacturing Method of Sliding Member]
The method for manufacturing a sliding member according to the second embodiment of the present invention is a method for manufacturing the sliding member according to the first embodiment of the present invention, using a physical vapor vapor deposition method on the substrate. The step of forming the first amorphous carbon layer and the step of forming the second amorphous carbon layer on the first amorphous carbon layer are included. In the step of forming the crystalline carbon layer, the maximum temperature reached of the base material is controlled to 150 ° C. or lower.

The physical vapor deposition method (PVD method) is an amorphous method in which carbon ions obtained by evaporating and ionizing a carbon material are sprayed onto the base material to deposit the carbon ions on the base material. It is a method of forming a quality carbon layer.

In one embodiment of the present invention, the type of physical vapor deposition method is not particularly limited, and a method generally used for forming an amorphous carbon layer can be appropriately adopted. As the physical vapor deposition method, a filtered vacuum arc vapor deposition method using a filtered vacuum arc PVD device (also referred to as a filtered vacuum arc (FVA) device) for filtering macroparticles generated from the target is adopted. Is preferable.

In the step of forming the first amorphous carbon layer in one embodiment of the present invention, the maximum temperature reached of the base material is controlled to 150 ° C. or lower, preferably 130 ° C. or lower.

In the step of forming the first amorphous carbon layer, the starting point of the abnormal growth product in the first amorphous carbon layer formed by controlling the maximum temperature reached of the base material within the above range. It is possible to control the density of the macroparticles to be in a suitable range.

The method for controlling the maximum temperature of the base material is not particularly limited, and for example, in the step of forming the first amorphous carbon layer, the formation of the first amorphous carbon layer is appropriately interrupted. The step of cooling the base material once or a plurality of times, a method of controlling the temperature of the base material by using a heater, and the total amount of ion energy applied to the base material are controlled. The method can be mentioned. More specifically, a method of adjusting the number of FVA evaporation sources, a method of adjusting the magnitude of the arc current used for forming the first amorphous carbon layer, a method of adjusting the substrate bias, and the like are mentioned. Can be done.

Here, when the amorphous carbon layer is formed by the physical vapor vapor deposition method, ionized carbon is sprayed onto the base material, so that ion energy is inevitably applied to the base material. The total amount of ion energy applied at that time varies depending on the characteristics such as the layer thickness of the target amorphous carbon layer. That is, in order to form an amorphous carbon layer having characteristics such as a layer thickness in a specific range, it is necessary to add a total ion energy amount in a specific range to the substrate.

When the total amount of ion energy is large, the temperature of the base material tends to rise. On the other hand, when the total amount of ion energy is small, the temperature of the base material is unlikely to rise. Therefore, as a more detailed specific example of the method for controlling the maximum temperature reached of the base material, when the total amount of ion energy for forming the target amorphous carbon layer is large, the amorphous material is described. A method of controlling the temperature of the base material so that the temperature of the base material does not rise excessively by carrying out the step of cooling the base material once or a plurality of times by appropriately interrupting the formation of the carbon layer can be mentioned. Be done. Further, if necessary, the maximum temperature reached of the base material can be controlled without heating the heater. Further, when the total amount of ion energy for forming the target amorphous carbon layer is small, a method of heating the base material with a heater to control the temperature of the base material is given. Can be done.

Further, in the step of forming the first amorphous carbon layer, in addition to controlling the maximum temperature reached of the base material to 150 ° C. or lower, the film thickness of the first amorphous carbon layer is increased. It is preferable to form a film until the film thickness is 100 nm or more, m and 20% of the total film thickness of the coating film, and the thickness is equal to or less than the thicker layer thickness. This makes it possible to more preferably improve the smoothness of the sliding member and preferably prevent the coating film from peeling off from the sliding member.

In the step of forming the second amorphous carbon layer in one embodiment of the present invention, the method for forming the second amorphous carbon layer is not particularly limited, and the forming of the amorphous carbon layer is not particularly limited. A commonly used method can be appropriately adopted. As a method for forming the second amorphous carbon layer, a physical vapor deposition method can be preferably adopted as in the step of forming the first amorphous carbon layer, which is more preferable. Can employ a filtered vacuum arc deposition method.

In the step of forming the second amorphous carbon layer in one embodiment of the present invention, forming the second amorphous carbon layer on the first amorphous carbon layer means that the second amorphous carbon layer is formed. Forming the second amorphous carbon layer directly on the amorphous carbon layer of 1, and between the first amorphous carbon layer and the second amorphous carbon layer, In the case of manufacturing a sliding member on which another layer such as another amorphous carbon layer is formed, both of forming the second amorphous carbon layer on the other layer are included.

In the step of forming the second amorphous carbon layer in one embodiment of the present invention, the hardness of the second amorphous carbon layer becomes lower than the hardness of the first amorphous carbon layer. As such, the manufacturing conditions are controlled. As a method for controlling the hardness of the second amorphous carbon layer, a method known to those skilled in the art can be adopted. As a method for controlling the hardness of the second amorphous carbon layer, specifically, for example, the temperature of the base material in the step of forming the second amorphous carbon layer is set to the first one. Examples include controlling the temperature to a temperature equal to or higher than the maximum reached temperature of the base material in the step of forming the amorphous carbon layer.

The method for controlling the temperature of the base material to a temperature equal to or higher than the maximum reached temperature of the base material in the step of forming the first amorphous carbon layer is not particularly limited, and for example, a heater is used. A method of heating the substrate, a method of controlling the total amount of ion energy applied to the substrate in the case of adopting a filtered vacuum arc vapor deposition method, and more particularly, a method of increasing the number of FVA evaporation sources. Examples thereof include a method of coating using a high arc current and a method of increasing the substrate bias.

The method for manufacturing the sliding member according to the embodiment of the present invention is optional, other than the step of forming the first amorphous carbon layer and the step of forming the second amorphous carbon layer. Can include the steps of.

The other steps include a step of forming the intermediate layer on the base material, and another amorphous carbon between the first amorphous carbon layer and the second amorphous carbon layer. Examples thereof include a step of forming the layer, a step of forming the wear-resistant surface treatment layer on the second amorphous carbon layer, and the like.

In the other steps, known methods for forming the respective layers of the intermediate layer, the other amorphous carbon layer and the wear-resistant surface-treated layer can be adopted.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Measurement of physical properties]
In Examples and Comparative Examples, the physical properties of the sliding member and the first amorphous carbon layer and the second amorphous carbon layer constituting the sliding member were measured by the following methods.

[Layer thickness, film thickness]
The sliding members manufactured in Examples and Comparative Examples were cut in a direction perpendicular to the surface of the base material. Then, the cross section obtained by the cutting is chemically polished by an ion milling method (CP processing), and then the cross section is observed using a scanning electron microscope (SEM) to obtain the first amorphous substance. The film thickness of the entire coating film including the carbon layer and the second amorphous carbon layer, and the first amorphous carbon layer and the second amorphous carbon layer was measured.

[Density of abnormal growth]
In the sliding members manufactured in Examples and Comparative Examples, after observing with an optical microscope at a magnification of 1000 times with respect to an arbitrary cross section obtained by the same method as the above-mentioned measurement of layer thickness and film thickness, Furthermore, SEM is performed under the condition of a microscope evaluation length of 340 μm to determine whether the abnormal growth product has macroparticles present in the first amorphous carbon layer or the second amorphous carbon layer as nuclei. The number of abnormal growths in the entire coating film and the number of abnormal growths starting from the macroparticles of the first amorphous carbon layer were measured using and observed.

The number of abnormal growth substances having macroparticles as nuclei of the obtained first amorphous carbon layer was divided by the product of the evaluation length of the microscope of 340 μm and the layer thickness of the first amorphous carbon layer. The value was calculated. Then, this calculated value was used as the density of the abnormal growth product having macroparticles as nuclei existing in the first amorphous carbon layer.

Similarly, the value obtained by dividing the number of abnormal growth substances in the entire coating film obtained by the product of the evaluation length of the microscope of 340 μm and the film thickness of the coating film is calculated, and the macro particles existing in the coating film are obtained. The density of abnormal growth substances as nuclei was used.

[hardness]
For the sliding members manufactured in Examples and Comparative Examples, the hardness of the first amorphous carbon layer and the second amorphous carbon layer was measured by using the carotest method.

Specifically, a carotest was performed on the sliding member using a steel ball having a ball diameter of 30 mm and a diamond slurry having a particle size larger than 0 μm and 2 μm or less. At that time, a carotest was performed so that the diameter of the carotest mark on the Cr substrate, which will be described later, was 25% or less of the diameter of the carotest mark of the obtained film (amorphous carbon film). The hardness was measured by the nanoindentation method, and was measured under the conditions of a triangular pyramid indenter (Berkovich indenter) and a load of 300 mgf. Specifically, the hardness of the first amorphous carbon layer and the second amorphous carbon layer was measured using an ultrafine indentation hardness tester (ENT-1100a manufactured by Elionix Inc.).

[Raman spectrum]
In the sliding members manufactured in Examples and Comparative Examples, Raman was applied to each of the first amorphous carbon layer and the second amorphous carbon layer in the calotest marks obtained by the above-mentioned hardness measurement. The Raman spectrum was measured using a spectroscopic analyzer (NRS-5100 manufactured by Nippon Spectroscopy Co., Ltd., wavelength 532 nm). After removing the baseline from the obtained Raman spectrum by a straight line, peak separation was performed on the D peak existing near the wave number 1350 cm ^-1 and the G peak existing near the wave number 1550 cm ^-1 . Then, the peak areas of the D peak and the G peak separated from the peak, and the peak position of the G peak were measured. The value of the peak area ratio ID / IG was calculated based on the measured peak areas of the D peak and the G peak. Further, the measured wave number at the peak position of the G peak was used as the value of the G peak shift.

[Surface roughness]
In the sliding members manufactured in Examples and Comparative Examples, the surface roughness of the coating film was roughened by a method according to ANSI B46.1 using a measuring device of a palpation type roughness meter (Dektak 150 manufactured by ULVAC, Inc.). Ra was measured. Subsequently, the measured surface roughness Ra value was divided by the film thickness of the coating film to calculate the surface roughness (Ra / film thickness) per unit film thickness.

[Adhesion]

For the sliding members manufactured in Examples and Comparative Examples, a Rockwell hardness tester (ARK-600 manufactured by Akashi Seisakusho Co., Ltd.) was used to the surface of the sliding member on the opposite side to the base material. From the outermost surface), a load of 150 kgf is applied with a diamond indenter at 120 ° C. (HRC test) to make an indentation on the outermost surface of the sliding member, and then the damaged state in the vicinity of the indentation is based on the VDI 3198 standard. It was classified into. In Table 3 below, HF1 to HF4 are represented by “◯” in the damage state evaluation in the standard, and HF5 to HF6 are represented by “x” in the damage state evaluation in the standard.

[Examples 1 to 17, Comparative Examples 1 to 2]
(Manufacturing of sliding members)
As a base material, a steel material made of chromium molybdenum steel (trade name: SCM415, Rockwell hardness (HRC): about 58) was used.

The base material was placed in a base material holder in a vacuum chamber of a filtered vacuum arc PVD device (hereinafter, FVA device) that filters macroparticles generated from a target. The base material holder was a base material holder that rotated 2R.

Subsequently, the vacuum chamber was evacuated. After that, argon (Ar) gas is introduced into the vacuum chamber that has been evacuated, and Ar plasma is generated by glow discharge, and then Ar plasma using secondary electron emission is generated to generate the group. The surface of the material was cleaned.

In the vacuum chamber, the cleaned base material was sputtered with a chromium (Cr) target to coat the base material with an intermediate layer (Cr base) made of Cr. Then, while evacuating the inside of the vacuum chamber, the base material was left to cool until the temperature of the base material became less than 100 ° C.

After the temperature of the base material has dropped, the maximum temperature reached of the base material in the vacuum chamber under the conditions of Ar gas: 3 scc, base material bias: 0 V, and arc current 150 A is shown in Table 1 below. In the gas phase state using the physical gas phase vapor deposition method while controlling the temperature of the base material so as to be the "maximum temperature reached" at the time of "formation of the first amorphous carbon layer" described in 1. By spraying the ionized carbon (C) onto the base material, a first amorphous carbon layer is formed on the base material, and the base material is used on the first amorphous carbon layer. Covered.

Here, when the total amount of ionic energy applied to the base material for forming the target first amorphous carbon layer is large, the formation of the first amorphous carbon layer is appropriately interrupted. A method of controlling the temperature of the base material by carrying out the step of cooling the base material once or a plurality of times so that the temperature of the base material does not rise excessively, and a target first non-crystal. When the total amount of ionic energy for forming the quality carbon layer is small, a method of heating the base material with a heater to control the temperature of the base material is appropriately adopted to control the temperature of the base material. The maximum temperature reached, that is, the temperature of the substrate was controlled to the temperature shown in Table 1 below.

After forming the first amorphous carbon layer, the first amorphous carbon layer is formed in the vacuum chamber under the conditions of Ar gas: 3 scc, substrate bias: 0 V, and arc current 150 A. In the temperature range, which is higher than the maximum reached temperature of the base material at the time, and the maximum reached temperature is the "highest reached temperature" in the "during the formation of the second amorphous carbon layer" shown in Table 1 below. The first amorphous carbon layer is formed by spraying ionized carbon (C) onto the substrate in a vapor phase state using a physical vapor vapor deposition method while controlling the temperature of the substrate. A second amorphous carbon layer was formed on the substrate, and the base material was coated with a film composed of the first amorphous carbon layer and the second amorphous carbon layer. As a result, a sliding member made of the coating film and on the substrate was manufactured.

Here, when forming the second amorphous carbon layer, the base material was heated. As a method for heating the base material, a method of heating the base material to control the temperature of the base material by using a heater, and a range in which the target second amorphous carbon layer can be formed. In the above, a method of controlling the total amount of ion energy applied to the substrate, more specifically, a method of increasing the number of FVA evaporation sources, a method of covering with a high arc current, and a method of increasing the substrate bias are appropriately adopted. did.

[Comparative Example 3]
As a base material, a steel material made of chromium molybdenum steel (trade name: SCM415, Rockwell hardness (HRC): about 58) was used.

The base material was placed in a base material holder in a vacuum chamber of a filtered vacuum arc PVD device (hereinafter, FVA device) that filters macroparticles generated from a target. The base material holder was a base material holder that rotated 2R.

Subsequently, the vacuum chamber was evacuated. After that, argon (Ar) gas is introduced into the vacuum chamber that has been evacuated, and Ar plasma is generated by glow discharge, and then Ar plasma using secondary electron emission is generated to generate the group. The surface of the material was cleaned.

In the vacuum chamber, the cleaned base material was sputtered with a chromium (Cr) target to coat the base material with an intermediate layer (Cr base) made of Cr. Then, while evacuating the inside of the vacuum chamber, the base material was left to cool until the temperature of the base material became less than 100 ° C.

After the temperature of the base material is lowered, Ar gas: 3 scc, base material bias: 0 V, arc current in the vacuum chamber without forming the first amorphous carbon layer on the base material. While controlling the temperature of the substrate so that the maximum reached temperature becomes the "maximum reached temperature at the time of forming the second amorphous carbon layer" shown in Table 1 below under the condition of 150 A. A second amorphous carbon layer is formed on the base material by spraying ionized carbon (C) onto the base material in the gas phase state using the physical gas phase vapor deposition method. , The base material was coated with a film made of the second amorphous carbon layer. As a result, a sliding member made of the coating film and on the substrate was manufactured.

(result)
The production conditions such as the maximum temperature of the base material and the formation time of the amorphous carbon layer in Examples 1 to 17 and Comparative Examples 1 to 3 are shown in Table 1 below. Further, the sliding members manufactured in Examples 1 to 17 and Comparative Examples 1 to 3, the first amorphous carbon layer and the second amorphous carbon layer constituting the sliding member, and the second amorphous carbon layer, and the like. The physical characteristics of the coating film measured by the above-mentioned method are shown in Tables 2 and 3 below.

(Conclusion)
With reference to Tables 2 and 3, from the comparison between Examples 1 to 17 and Comparative Examples 1 and 2, a first amorphous carbon layer having a higher hardness and a lower hardness first on the substrate. In the sliding member in which the coating film containing the amorphous carbon layer 2 is laminated, the density of the abnormal growth material having macroparticles as nuclei existing in the first amorphous carbon layer is 11.8 ×. The sliding member having ^10-3 pieces / μm ² or less has an abnormal growth density of 11.8 × ^10-3 pieces / μm ² starting from macroparticles existing in the first amorphous carbon layer. It was found that the surface roughness was smaller and the smoothness was superior to that of the larger sliding member.

Further, from the comparison between Examples 1 to 17 and Comparative Example 3, it was found that the surface roughness of the coating film deteriorated when the first amorphous carbon layer was not contained. Therefore, including the first amorphous carbon layer having a high hardness and the second amorphous carbon layer having a low hardness on the substrate also reduces the surface roughness of the coating film and smoothes the sliding member. It was found that it contributed to improving the sex.

From the above-mentioned matters, it was found that the sliding member according to the first embodiment of the present invention has an effect of being excellent in smoothness.

Further, from the comparison between Examples 1 to 16 and Example 17, when the hardness of the first amorphous carbon layer exceeds 80 GPa and is large for cross-linking, peeling occurs between the base material and the coating film. However, it was found that the adhesion was reduced.

As shown in Table 1, in Examples 1 to 17, the maximum temperature reached of the base material at the time of forming the first amorphous carbon layer is controlled to a low temperature of 150 ° C. or lower. Further, in Examples 1, 9 to 12 and 14 to 17, and in Comparative Example 2, the formation time is 1 Hour at the time of forming the first amorphous carbon layer. On the other hand, regarding the maximum temperature reached of the base material at the time of forming the first amorphous carbon layer, Examples 1, 9 to 12 and 14 to 17 have a low temperature of 150 ° C. or lower, while Comparative Example 2 has a low temperature of 150 ° C. or less. It is 160 ° C. That is, the maximum temperature reached of the base material at the time of forming the first amorphous carbon layer in Comparative Example 2 is a temperature exceeding 150 ° C. As a result, in Examples 1, 9 to 12 and 14 to 17, the density of the abnormal growth material having macroparticles as nuclei existing in the first amorphous carbon layer becomes smaller than that in Comparative Example 2. ing.

From the above items, by controlling the maximum temperature reached of the base material at the time of forming the first amorphous carbon layer to a low temperature of 150 ° C. or less, the macroparticles existing in the first amorphous carbon layer can be obtained. It was found that the sliding member according to the first embodiment of the present invention can be manufactured by appropriately controlling the density of the amorphous growth material as a core.

According to one embodiment of the present invention, it is possible to obtain a sliding member having a small surface roughness and excellent smoothness. This sliding member having excellent smoothness is used for manufacturing, for example, a sliding part having excellent durability when operated for a long time in a mechanical device such as an engine for a vehicle and whose accuracy does not easily decrease. be able to.

1 Base material 2 First amorphous carbon layer 3 Second amorphous carbon layer 4 First amorphous carbon layer 5 Second amorphous carbon layer 6 Outermost surface 7 Abnormalities centered on macroparticles Growth product

Claims (6)

A sliding member including a base material and a coating film covering at least a surface of the base material that slides on the mating material.
The coating comprises a first amorphous carbon layer and a second amorphous carbon layer.
The first amorphous carbon layer is formed between the base material and the second amorphous carbon layer.
The first amorphous carbon layer has a higher hardness than the second amorphous carbon layer.
In the cross section of the coating film, the density of abnormal growth products having macroparticles as nuclei existing in the first amorphous carbon layer is 11.8 × 10 ^-3 / μm ² or less. Sliding member. Claimed, the first amorphous carbon layer has a layer thickness of 100 nm or more, and is not more than 1000 nm, which is thicker than 20% of the total film thickness of the coating film. The sliding member according to 1. The sliding member according to claim 1 or 2, wherein the hardness of the first amorphous carbon layer is 40 GPa or more and 80 GPa or less. Claim 1 is characterized in that the ID / IG value of the first amorphous carbon layer obtained by Raman spectroscopy is 1.0 or less, and the G peak shift is 1535 cm ^-1 or more and 1570 cm ^-1 or less. The sliding member according to any one of 3 to 3. The sliding member according to any one of claims 1 to 4, wherein the film thickness is 1 μm or more and 50 μm or less. The method for manufacturing the sliding member according to any one of claims 1 to 5.
A step of forming the first amorphous carbon layer on the substrate by using a physical vapor deposition method, and
A step of forming the second amorphous carbon layer on the first amorphous carbon layer is included.
A method for manufacturing a sliding member, which comprises controlling the maximum temperature reached of the base material to 150 ° C. or lower in the step of forming the first amorphous carbon layer.

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