阅读说明：本技术 Dlc涂层构件的表面处理方法 (Surface treatment method for DLC coated member ) 是由 间瀬恵二 石桥正三 近藤祐介 于 2019-11-26 设计创作，主要内容包括：本发明涉及DLC涂层构件的表面处理方法,该方法包括：将DLC涂层构件当作处理对象,所述DLC涂层构件具有涂在基材表面上的DLC膜；以0.01MPa～0.7MPa的喷射压力,将中位直径为1μm～20μm且穿过空气的下落时间不小于10s/m的大致球形的喷射颗粒喷射到所述构件的所述膜的表面上；以及在不露出所述基材的情况下,在所述膜的所述表面上形成凹坑,使得所述凹坑的总投影面积不小于处理区域的50％,并且使得所述DLC膜的所述表面被加工成算术平均高度(Sa)为0.01μm～0.1μm并且纹理纵横比(Str)不小于0.4。(The present invention relates to a surface treatment method of a DLC-coated member, the method comprising: a DLC coated member having a DLC film coated on a surface of a substrate is used as a treatment object; spraying roughly spherical spray particles having a median diameter of 1 to 20 μm and a falling time through air of not less than 10s/m onto the surface of the membrane of the member at a spray pressure of 0.01 to 0.7 MPa; and forming pits on the surface of the film without exposing the substrate such that a total projected area of the pits is not less than 50% of a treated area, and such that the surface of the DLC film is processed to an arithmetic average height (Sa) of 0.01 μm to 0.1 μm and a texture aspect ratio (Str) is not less than 0.4.)

A surface treatment method of a DLC-coated member, the method comprising:

a DLC coated member having a DLC film coated on a surface of a substrate is used as a treatment object;

spraying roughly spherical spray particles having a median diameter D50 of 1 to 20 μm and a falling time through air of not less than 10s/m onto the surface of the DLC film of the DLC coating member at a spray pressure of 0.01 to 0.7 MPa; and

forming pits on the surface of the DLC film without exposing the substrate such that a total projected area of the pits is not less than 50% of a processed area, and such that the surface of the DLC film is processed to have an arithmetic average height of 0.01 to 0.1 μm and a texture aspect ratio of not less than 0.4.

2. The method according to claim 1, wherein the ejection velocity of the ejected particles is not less than 80 m/s.

3. The method according to claim 1 or 2, wherein the treatment object is the DLC coated member having the DLC film formed on the substrate surface smoothed to a surface roughness Ra of not more than 0.1 μm.

Technical Field

The present invention relates to a surface treatment method of a member coated with a diamond-like carbon (DLC) film, and more particularly, to a surface treatment method of a DLC coated member for forming a plurality of fine pits so as to exhibit advantageous effects such as reduction in sliding resistance on the surface of the DLC film on the DLC coated member.

Background

DLC, which is amorphous (amorphous) hard carbon, has high hardness, has excellent wear resistance, and also has characteristics such as low friction coefficient and resistance to adhesion of other materials. Therefore, coating the cutting edge of the cutting tool, the sliding surface of the sliding member, and the inner surface of the die cavity with the DLC film is a method for surface modification, the purpose of which is to improve wear resistance and sliding property, and to improve mold release property (demolding property), and the like.

Therefore, the DLC-coated member coated with the DLC film has the following advantageous effects: low coefficient of friction, excellent wear resistance, and excellent mold release properties. However, it has also been proposed to form a plurality of fine pits serving as oil reservoirs and the like on the surface of the DLC film, with the object of achieving further improvements in such DLC-coated members in terms of reducing the friction coefficient and improving wear resistance, and achieving further improvements in mold release properties and the like.

A method for forming such a pit has been proposed in which, for example, an indentation that will become such a pit is formed on the surface of a substrate (base material) before a DLC film is formed. Then, by forming the DLC film on the surface of the substrate, pits formed on the substrate will also appear on the surface of the DLC film.

However, this method may result in unevenness in the quality of the film, for example, the film thickness of the DLC film is thin at the portion hidden inside the indentation formed on the substrate and is thick at the protrusion. In addition to this, this results in that the profile of the pits formed on the DLC film does not accurately reflect the profile of the indentations and protrusions formed on the substrate. This means that: since indentations and protrusions need to be formed on the substrate, experience and intuition are required to form pits having a desired profile on the DLC film while taking such variations in profile and the like into consideration.

Therefore, a method of forming pits directly on the DLC film without forming indentations on the substrate side is proposed.

Such a method comprises: a method of forming a pit simultaneously with the process of forming the DLC film, and a method of forming a pit by post-treatment after forming the DLC film in advance.

One of these methods is disclosed in japanese patent application laid-open (hereinafter, referred to as JP- ｃA) No. 2004-339564 as ｃA method of forming pits simultaneously with the process of forming ｃA DLC film. The method uses unbalanced magnetron sputtering (unbalanced magnetron sputtering) as follows: wherein ｃA bias voltage applied to the substrate side is adjusted during the formation of the DLC film so that fine pits can be formed on the surface of the DLC film thus obtained (see claims 4 and 5 in JP-A No. 2004-339564).

Also disclosed in JP-A No. 2006-38000 is ｃA method of: wherein after the DLC film is formed, pits are formed by post-treatment using plasma etching, focused ion beam, or laser treatment. JP-A No. 2005-193390 also discloses ｃA method of: wherein pits are formed by partially removing the DLC coating using ｃA focused ion beam (see claims 4 and 6, etc. in JP- ｃA 2006-.

Further, ｃA separate method for forming pits by post-treatment after forming the DLC film is also disclosed in JP- ｃA No. 2010-126419 described below. In this method, pits are formed by ejecting fine particles made of ｃA ceramic material or the like onto the surface of the DLC film at ｃA high speed so as to cause fine-size peeling (detachment) of the DLC film and expose the surface of the substrate constituting the lower layer and the surface of the intermediate layer (see paragraph [0016] in JP- ｃA No. 2010-126419) (formation of pits by fine particles hitting the DLC coating member is also mentioned in international publication WO 2017/169303 described below).

It is to be noted that, although not related to the surface treatment of the DLC-coated member, the applicant of the present invention has filed an application related to a surface treatment method of a metal article, the purpose of which is to continuously form a uniform nanocrystalline structure along the surface of a metal article composed of a soft material and a hard material. In this method, roughly spherical sprayed particles having ｃA median diameter D50 of 1 to 20 μm and ｃA falling time through air of not less than 10s/m are sprayed onto ｃA metal article at ｃA spraying pressure of 0.05 to 0.5MPｃA, so that ｃA uniform nanocrystal structure is continuously formed along the surface of the metal article in ｃA region from the surface of the metal article to ｃA specified depth by being micronized into nanocrystals having an average crystal grain diameter of not more than 300nm and applying ｃA compressive residual stress to the surface of the metal article (see claim 1 and the like in JP-A No. 2017-206761).

From among the above-described methods for forming pits on ｃA DLC film, as in the method described in JP-A No. 2004-339564, the formation of pits during the process of forming ｃA DLC film is excellent from the viewpoint that pits can be formed without damaging or destroying the formed DLC film.

However, the method for forming the DLC film is limited to the unbalanced magnetron sputtering method. In the unbalanced magnetron sputtering method, mechanical properties such as smoothness, hardness, and the like of the DLC film to be formed are controlled by changing a bias applied to the substrate. Therefore, in the method of forming an indentation on the surface of DLC by controlling the bias voltage within a specified range (150V to 600V) described in JP-a2004-339564, the mechanical characteristics of the DLC film obtained thereby are also limited, and furthermore, it is cumbersome to adjust the operating conditions and the like in order to form an indentation of a desired size on the surface of the DLC film.

In contrast to this, in a method of forming a pit by removing a part of a formed DLC film after the DLC film has been formed, it is not limited to using an unbalanced magnetron sputtering method, and without limiting a method for forming DLC, pits may be formed on various DLC films that have been formed by other methods such as ordinary magnetron sputtering (balanced magnetron sputtering), vacuum deposition, plasma CVD, and the like.

In particular, in the methods of forming pits by emitting fine particles described in JP- ｃA No. 2010-126419 and international publication WO 2017/169303, the pits may be formed by using ｃA jetting device having pneumatic jetting or the like (see paragraph [0027] in JP- ｃA No. 2010-126419), that is, by using ｃA blasting device (see paragraph [0076] in international publication WO 2017/169303). Therefore, since the pits can be formed using ｃA simpler apparatus configuration than the method of removing the DLC film by plasmｃA etching, focused ion beam or laser processing of JP- ｃA No. 2006-.

However, since the formation of pits according to these two methods is achieved by a configuration in which small-scale removal or peeling is performed on the already-formed DLC film, that is, the pits are formed as the DLC film is damaged, further cracking or peeling of the DLC film is easily generated at the portions where the pits are formed.

In view of this, JP-A No. 2010-126419 describes ｃA method of forming pits by emitting fine particles, in which it is indicated that the total coverage of pits should not exceed 10% of the total surface, and also that if the formed pits exceed this range, peeling of the DLC film easily occurs (see paragraphs [0016] to [0017] in JP-A No. 2005-193390).

Therefore, this method cannot form the pits at a coverage ratio (i.e., 50% or more) that can sufficiently exhibit a function of improving the slidability using the pits.

As well known to those skilled in the art, the DLC film is fragile due to a thin film thickness and high stress, so that the DLC film is easily broken and peeled off upon a strong impact. Therefore, in JP-A No. 2010-126419, such characteristics of the DLC film are used to form pits by causing peeling of the DLC film at portions struck by fine particles.

Therefore, in this method, the pits are formed by the treatment of giving damage called local peeling to the DLC film as described above. Therefore, the coverage of the pits formed in this manner is inevitably limited.

However, the method of forming the pits by emitting fine particles is excellent from the viewpoint that the pits can be formed relatively inexpensively by using a known blasting device or the like.

Accordingly, an object of the present invention is to provide a surface treatment method of a DLC-coated member, which method is capable of forming pits on the surface of a DLC film without occurrence of local peeling of the DLC film and consequent exposure of a substrate while being able to form pits relatively simply by impact of fine particles, and which method is capable of forming pits so that the total projected area (total projected area) is not less than 50% of the treated area, thereby being able to impart functions such as improved slidability.

Disclosure of Invention

In order to achieve the object, a surface treatment method of a DLC-coated member of the present invention includes:

a DLC coated member having a DLC film coated on a surface of a substrate is used as a treatment object;

spraying roughly spherical spray particles having a median diameter D50 of 1 to 20 μm and a falling time through air of not less than 10s/m onto the surface of the DLC film of the DLC coating member at a spray pressure of 0.01 to 0.7 MPa; and

forming pits on the surface of the DLC film without exposing the substrate such that a total projected area of the pits is not less than 50% of a treated area, and such that the surface of the DLC film is processed to have an arithmetic average height (Sa) of 0.01 to 0.1 μm and a texture aspect ratio (Str) of not less than 0.4.

In the surface treatment method of the DLC-coated member, the ejection speed of the ejected particles is preferably not less than 80 m/s.

In the surface treatment method of a DLC-coated member, the treatment object is preferably a DLC-coated member having a DLC film formed on the substrate surface smoothed to a surface roughness Ra of not more than 0.1 μm.

The surface treatment method of the present invention as described above can exhibit the following remarkable advantageous effects.

That is, heretofore, in ｃA surface treatment method (JP- ｃA No. 2010-126419) of forming pits on ｃA DLC film by the impact of similarly jetted fine particles, pits were formed in the DLC film by local destruction and peeling of the DLC film to expose the substrate. However, in the surface treatment method of the present invention, pits can be formed on the surface of the DLC film without causing peeling of the DLC film and accompanying exposure of the substrate due to local destruction of the DLC film.

As a result, even in the case where pits having a total projected area of not less than 50% of the processing region have been formed on the surface of the processing target region, the method of the present invention can prevent the DLC film from peeling off or the like at the time of use.

Although the mechanism by which the surface treatment method of the present invention can form pits without accompanying the damage and peeling of the DLC film is not completely understood, the blasting particles used in the method of the present invention are small, the median diameter D50 is in the range of 1 μm to 20 μm, and the mass of the blasting particles is small so that the falling time through the air is not less than 10 s/m. This means that: when the surface of the DLC film is struck, stress is locally concentrated at the struck portion and in the vicinity of the surface so as not to penetrate to the interface with the substrate.

However, the ejected particles, as defined above, are easily carried by the airflow and may be propelled at a velocity close to the airflow velocity. This enables the sprayed particles to be sprayed at a high speed close to the flow speed of the gas flow flowing inside the spray nozzle, for example, at a speed of not less than 80m/s even when sprayed at a relatively low spray pressure of about 0.01 MPa.

In this way, although peeling of the DLC film can be prevented because the stress during impact is locally concentrated and does not reach a deeper portion (interface with the substrate), since the blasting is performed at high speed, high impact energy can still be obtained. This is considered to mean that the density of the DLC film can be increased by the energy at the time of impact of the fine particles, and also can be increased by the reconstruction of the structural destruction occurring simultaneously due to the impact, so that pits can be formed without causing damage and peeling of the DLC film and without exposing the substrate.

Drawings

The objects and advantages of the present invention will become apparent from the detailed description of the preferred embodiments of the invention provided in conjunction with the accompanying drawings, in which:

fig. 1 is a surface roughness profile of an untreated DLC coated member (comparative example 1) measured by a laser microscope.

Fig. 2 is a surface roughness distribution diagram of the DLC coated member (example 1) subjected to the surface treatment method of the present invention measured by a laser microscope.

Fig. 3A and 3B are electron micrographs of the mold surface: fig. 3A is an electron micrograph of an untreated mold surface (comparative example 1), and fig. 3B is an electron micrograph of a mold surface subjected to the surface treatment method of the present invention (example 1).

Detailed Description

The following is a description of exemplary embodiments of the invention.

Treatment object product

The object treated by the surface treatment method of the present invention has a surface coated with a DLC film, and further has pits formed on the surface, so as to exhibit advantageous effects such as improvement of slidability and improvement of releasability due to an oil reservoir, an air reservoir (air reservoir), a release agent container (release agent reservoir), and the like. For example, the object treated using the present invention may be any of various DLC coated members such as a cutting edge of a cutting tool, a sliding surface of a sliding member (e.g., a bearing, a shaft, etc.), and a molding surface of various molds, on which a DLC film is formed, and which also find beneficial effects from forming pits on the surface of the DLC film. The DLC-coated member is not limited to a member completely coated with DLC, and may be partially coated with DLC.

The material of the substrate of the DLC coating member as the treatment object is not particularly limited as long as it is a material on which a DLC film can be formed. Examples of the material to be treated include various metal substrates such as cemented carbide, cold work die steel, high speed tool steel, or stainless steel, and include ceramic substrates.

Note that, in the case where an underlayer is formed on the surface of the processing target member and then a DLC film is formed on the surface of the underlayer, the underlayer corresponds to the substrate of the present invention.

Preferably, the DLC coating member serving as the treatment object is a treatment object having a DLC film formed on a substrate surface polished to a mirror finish (mirrorfinish) having a surface roughness Ra of not more than 0.1 μm. This is because if the surface roughness Ra exceeds 0.1 μm, the tips of the indentations and protrusions are liable to become starting points of breakage, so that peeling easily occurs when handling by the present invention.

There is no particular limitation on the method for forming the DLC film on the DLC coating member as the treatment object or the type of the formed DLC film. The DLC film subjected to the treatment of the present invention may be a high-hardness hydrogen-free DLC film called tetrahedral amorphous carbon (ta-C) formed using a vacuum arc deposition method, may be a low-hardness hydrogen-free DLC film called amorphous carbon (a-C) formed by a sputtering method or the like, and may be a hydrogen-containing DLC film called hydrogenated amorphous carbon (a-C: H) (among them, a film having a relatively high hardness called hydrogenated tetrahedral amorphous carbon (ta-C: H)) formed by a plasma CVD (chemical vapor deposition) method or the like. The object to be processed by the present invention may also be a DLC film formed with a diamond structure (sp3 bonding), a graphite structure (sp2 bonding), or a mixed structure of the two. The DLC film has a film thickness of 0.5 to 2.0. mu.m.

Surface treatment

Substantially spherical blasting particles are blasted onto a region where a pit is to be formed on the surface of the aforementioned DLC-coated member so as to impinge on the region.

Examples of the ejection particles, the ejection device, and the ejection conditions used when the above-described surface treatment is performed are given below.

(1) Blasting particles

With respect to the substantially spherical blasting particles used in the surface treatment method of the present invention, "substantially spherical" means that they do not need to be strictly "spherical", and for this reason, ordinary "shot blasting (shot)" may be used. Particles of any shape having no angle such as an elliptical shape and a barrel shape are included in the "roughly spherical blasting particles" used in the present invention.

Materials that may be used to eject the particles include metal-based materials and ceramic-based materials. Examples of materials for the metal-based sprayed particles include steel, high speed tool steel (HSS) (SKH), stainless steel (SUS), chrome boron steel (FeCrB), and the like. Examples of materials that may be used for the ceramic based spray particles include alumina (Al)₂O₃) Zirconium oxide (ZrO)₂) Zircon (ZrSiO)₄) Silicon carbide (SiC), glass, and the like.

As the particle diameter of the sprayed particles used, particles having a median diameter (D50) in the range of 1 μm to 20 μm were used.

"median diameter D50" refers to the diameter at 50% of the cumulative mass, i.e., the diameter when used as the diameter of particles for dividing a group of particles into two groups, results in the total mass of particles in the group of particles having the larger diameter being the same as the total mass of particles in the group of particles having the smaller diameter. This is the same as the definition of "particle diameter at cumulative 50% point" in JIS R6001 (1987). The median diameter can be measured by laser diffraction.

For fine powdery sprayed particles having a median diameter of 1 μm to 20 μm, the characteristic of long falling time of the sprayed particles through air (making the sprayed particles float in the air) can be imparted by selecting the material density of the sprayed particles. A sprayed particle having such characteristics tends to ride on the gas stream and may be propelled at a velocity similar to the flow velocity of the gas stream.

In the surface treatment method of the present invention, the blasting particles used have a falling time of not less than 10s/m under still air conditions. This enables the ejected particles to be ejected at substantially the same velocity as the flow velocity of the air stream ejected from the ejection nozzle of the blasting apparatus.

With respect to the falling speed, the longer the falling time is for the same particle diameter, the lower the density of the material constituting the sprayed particles is. For iron-based sprayed particles with a relative density of 7.85, the fall time was 10.6s/m for a particle diameter of 20 μm and 41.7s/m for a particle diameter of 10 μm. For the ceramic based sprayed particles with a relative density of 3.2, the falling time was 26.3s/m for a particle diameter of 20 μm and 100s/m for a particle diameter of 10 μm.

(2) Injection device

A known blasting device for blasting an abrasive together with a compressed gas may be used as the blasting device to blast the above-mentioned blasting particles toward the surface of the area to be treated.

Such blasting apparatuses are commercially available, for example, a suction type blasting apparatus that ejects abrasive using negative pressure generated by ejecting compressed gas, a gravity type blasting apparatus that causes abrasive falling from an abrasive tank to be carried and ejected by compressed gas, a direct pressure type blasting apparatus that introduces compressed gas into a tank filled with abrasive and ejects abrasive by combining a flow of abrasive from the abrasive tank with a flow of compressed gas from a separately provided compressed gas supply source, and a blower type blasting apparatus that uses a flow of gas generated by a blower unit to carry and eject a flow of compressed gas from such a direct pressure type blasting apparatus. The blasting device may be any one of the blasting devices described above to eject the blasting particles described above.

(3) Conditions of treatment

Substantially spherical blasting particles composed of one of the above materials or the like, having a median diameter D50 of 1 to 20 μm and a falling time through air of not less than 10s/m are blasted onto the DLC coating member as described above at a blast pressure of 0.01 to 0.7MPa to form pits without exposing the substrate.

Such blasting of the blasting particles is performed on the surface of the DLC film until the total projected area of the pits is not less than 50% of the processed area. Note that in this specification, the "projected area" refers to the outline area of the pit.

Further, the particles were sprayed so that the surface roughness of the DLC surface after treatment was an arithmetic average height Sa defined by ISO25178, which was in the range of 0.01 μm to 0.1 μm.

Further, the process is performed so as to achieve a texture aspect ratio (texture ratio) Str defined by ISO25178 of not less than 0.4, thereby processing the surface of the DLC film into a non-oriented surface.

Operation etc

The surface treatment method of the present invention as described above can form fine pits on the DLC film with a total projected area of not less than 50% of the treated area without causing the DLC film to peel off and thus without exposing the substrate.

As a result, the treatment by the method of the present invention can reduce the resistance during sliding. This is achieved by reducing the contact area between the DLC coating member having fine pits formed on the surface of the DLC film and the opposing member.

Further, the indentation-protrusion profile of the surface of the DLC coated member formed by the method of the invention is a profile dominated by smooth indentations and protrusions. This means that the inclination angle of the indentations and protrusions is shallow and also a reduction of the friction forces acting on the protrusions is achieved.

Further, since shallow pits of small diameter are formed, an air lubrication effect is obtained due to the formation of an air layer on the surface of the DLC film during sliding, thereby achieving an improvement in sliding properties.

Further, the formed dimples also serve as oil reservoirs, and therefore, improvement in slidability can be achieved both in the case where lubricating oil is applied to the sliding portion and in the case where lubricating oil is not applied.

Examples of the invention

Next, the results of comparative tests performed on the DLC coated member on which the surface treatment has been performed by the method of the present invention and the untreated DLC coated member will be given.

Roughness was measured using a profile analysis laser microscope (VK-X250 manufactured by keyence corporation) as described below, and measurement was performed at a measurement magnification of 3000 ×. Based on these analysis results, the profile thus obtained was calculated using analysis software (multi-file analysis application VK-H1MX) suitable for the laser microscope.

Test example 1: drawing Die for Forming Aluminum pot (Aluminum-Can-Forming Draw Die)

(1) Test method

10,000 aluminum cans were formed using an aluminum can-forming drawing die and an untreated aluminum can-forming drawing die, respectively, on which surface treatment had been performed by the method of the present invention. After forming the can using the above-described aluminum can forming drawing die, the state of peeling of the DLC film from the surface of the aluminum can forming drawing die and the state of adhesion of aluminum to the surface of the aluminum can forming drawing die were then evaluated by visual observation, respectively.

(2) Examples and comparative examples

After lap polishing (lap polishing) of the substrate surface to Ra of not more than 0.02 μm, a cemented carbide aluminum can forming drawing die was prepared by forming a DLC film having a film thickness of 0.5 μm on the substrate surface. Then, the surface treatment method of the present invention was performed on the mold surface under the conditions listed in table 1 (examples 1 to 3). Then, these dies and an untreated cemented carbide aluminum can forming drawing die (comparative example 1) were used to form aluminum cans, respectively.

TABLE 1

Examples 1 to 3 and comparative example 1

(3) Evaluation results

The measurement was performed using the above-mentioned laser microscope (VK-X250 manufactured by keyence corporation), and the respective surface roughness distributions of the mold are illustrated in fig. 1 (untreated: comparative example 1) and fig. 2 (surface treatment of the present invention: example 1).

An electron micrograph imaging the surface of each mold for the untreated (comparative example 1) is illustrated in fig. 3A, and an electron micrograph imaging the surface of each mold for the surface treatment of the present invention (example 1) is illustrated in fig. 3B.

Further, after forming the aluminum cans of the aluminum can forming drawing dies of examples 1 to 3 and the aluminum can forming drawing die of comparative example 1, the results listed in Table 2 below were confirmed by visually observing the peeling state of the DLC film and the state of aluminum adhesion.

TABLE 2

Results of confirming the peeling state and aluminum adhesion state of DLC film

	Example 1	Example 2	Example 3	Comparative example 1
					Peeling off of DLC film	Is free of	Is free of	Is free of	Local peeling
Aluminum adhesion	Very slight	Very slight	Light and slight	Is obvious

As is apparent from comparison with the surface of the untreated mold (comparative example 1) shown in fig. 1, it was confirmed that the surface of the mold subjected to the surface treatment of the present invention shown in fig. 2 had pits formed thereon.

These pits are formed to a DLC film thickness of 0.5 μm, and the pits are all formed to a depth of not more than 0.2 μm. Therefore, the surface treatment method of the present invention can form pits on the surface of the DLC-coated member without exposing the base material of the mold. This makes it possible to prevent the DLC film from peeling off with the pit formation position as a starting point, as in the case where partial peeling off of the DLC film has been caused.

Further, as is apparent from fig. 2 and 3B, the surface profile of the mold in which the dimples are formed using the surface treatment method of the present invention is mainly the indentations and protrusions having a relatively smooth profile, thereby achieving a reduction in the frictional force acting on the protrusions during sliding.

As a result, although local peeling of the DLC film and relatively large aluminum adhesion occurred after the aluminum can was formed using the aluminum can forming drawing die (comparative example 1) that was not surface-treated by the method of the present invention, peeling of the DLC film was not seen and only very slight or slight aluminum adhesion was observed with the aluminum can forming drawing dies (examples 1 to 3) that were subjected to the surface treatment method of the present invention. Thus, in comparison with the untreated DLC coated member, it can be confirmed that: performing the surface treatment by the method of the present invention can improve mechanical characteristics.

Test example 2: contour Punch (Profile Punch)

(1) Test method

The electrical part material (brass material) was die-cut 15,000 times using the contour punch surface-treated by the method of the present invention and the untreated contour punch, respectively. Then, the state of peeling of the DLC film from the surface of the contour punch after use was evaluated by visual observation.

(2) Examples and comparative examples

After lapping and polishing the substrate surface to Ra of not more than 0.02 μm, a cemented carbide contour punch was prepared by forming a DLC film with a film thickness of 1.5 μm on the substrate surface. Then, the surface treatment method of the present invention was performed on the cemented carbide contour punch under the conditions listed in table 3 (examples 4 to 6). Then, punching was performed using these contour punches and an untreated cemented carbide contour punch (comparative example 2), respectively.

TABLE 3

Examples 4 to 6 and comparative example 2

(3) Evaluation results

The results of the observed peeling state of the DLC films of the outline punches of examples 4 to 6 and the outline punch of comparative example 2 are listed in table 4 below.

TABLE 4

Peeling state of DLC film

The above results confirmed that the DLC film at the tip of the punch was peeled off after cutting the electric component material using the contour punch which was not subjected to the surface treatment method of the present invention (comparative example 2).

In contrast, no peeling of the DLC film was observed in any part of the contour punches (examples 4 to 6) surface-treated by the method of the present invention, including the tip part of the punches. This can confirm that: performing the surface treatment by the surface treatment method of the present invention can improve the mechanical characteristics of the punch compared to an untreated DLC-coated member.

Test example 3: part conveying rail

(1) Test method

The components were conveyed using the component conveying rail (example 7) surface-treated by the method of the present invention and the untreated component conveying rail (comparative example 3), respectively. Then, it was confirmed by visual observation whether the conveyed member would be jammed during the conveyance.

(2) Examples and comparative examples

After lapping and polishing the substrate surface to Ra of not more than 0.02 μm, a component conveying rail made of SUS304 was prepared by forming a DLC film having a film thickness of 1.5 μm on the substrate surface. Then, the surface treatment method of the present invention was performed on the component conveying rail under the conditions listed in table 5 (example 7). Then, the component was conveyed using the component conveying rail and the unprocessed component conveying rail (comparative example 3), respectively.

TABLE 5

Example 7 and comparative example 3

(3) Evaluation results

The results of visually confirming the seized state of the components conveyed by the component conveying rail of example 7 and the component conveying rail of comparative example 3 are listed in table 6 below.

TABLE 6

Jamming of conveyed components

	Example 7	Comparative example 3
			Jamming of conveyed components	Is free of	Some are

The above results confirmed that the seizure of the conveyed component occurred using the component conveying rail (comparative example 3) which had not been subjected to the surface treatment method of the present invention. The sticking at these portions is considered to be due to cracks and peeling generated in the DLC film.

In contrast to this, with the component conveying rails surface-treated by the method of the present invention (example 7), no seizure of the conveyed components was seen, and it could be confirmed that no crack and peeling were generated in the DLC film, and thus good slidability was exhibited.

Accordingly, the following claims, in their broadest sense, are not directed to a machine that is constructed in a particular manner. Rather, the broadest claims are intended to protect the heart or essence of the breakthrough invention. The present invention is clearly new and useful. Further, the present invention is not obvious to one of ordinary skill in the art in view of the prior art when considered in its entirety.

Furthermore, in view of the revolutionary nature of the present invention, this is clearly a pioneering invention. As such, the following claims are to be interpreted broadly, in accordance with the law, to protect the core of the invention.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Furthermore, it is to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

The invention has now been described.