JPH11310876A - Production of coated member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a member high in the adhesion between a base material and a coating film and whose surface has the smooth coating film. SOLUTION: The surface to be coated of a base material is previously applied to ion impact by using a gaseous mixture of a ruggedness forming gas contg. one or more kinds of a gas belonging to a rare gas and hydrogen and a ruggedness promoting gas contg. one or more kinds among nitrogen, carbon and oxygen and projecting parts in which the average height is in the range of 10 to 100 nm and the average width is in the range of 10 to 300 nm are formed to make them into rugged faces. By this rugged faces, a coating film formed thereon is firmly fixed. By jointly using the ruggedness promoting gas, the formation of the rugged faces is made easy and stable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated member in which a base material such as a steel material is coated with a hard film or the like, and to a method for manufacturing a coated member having improved adhesion between the base material and the coated film. It is.

[0002]

2. Description of the Related Art Several μm to several tens μm are formed on the surface of steel material or the like.
A coating member formed of a base material and a coating film formed on a surface by forming a vapor deposition film having a thickness, a sputtering film, an oxide film, or the like by a PVD method or a CVD method is widely used. In some cases, the adhesion between the base material forming the coating member and the coating film becomes a problem, and the coating film is peeled off. For example, P
In the technique of employing a VD method and coating a thin film at a low temperature of 600 ° C. or lower, the bonding between the base material and the coating film is weak due to the low temperature, and peeling often occurs.

In such a case, as a conventional means for enhancing the bond between the substrate and the coating film, a method of roughening the surface of the substrate by blasting the surface of the substrate (JP-A-1-29487).
5), a wet etching method, and a method of cleaning the surface by ion bombardment (Japanese Patent Laid-Open No. 2-1)
56066).

[0004]

In order to use the covering member as a sliding member, it is important that the covering film is smooth and has high adhesion to the substrate. If it is not smooth, the seizure resistance is low and the opponent aggression is high. In addition, if the adhesion to the base material is insufficient, peeling occurs and cannot be used as a sliding member.

However, in the conventional blasting method and wet etching method, the surface of the base material is greatly roughened, and the surface becomes uneven at least several microns, so that a smooth film cannot be obtained. For this reason, the surface roughness of the thin film to be subsequently coated is also deteriorated. For example, when used as a sliding member, the other member is attacked, and the required sliding characteristics cannot be obtained. Therefore, in the case of a sliding member or the like that requires a smooth surface, the hard film may need to be polished again.

In the method of cleaning the surface by ion bombardment, the purpose is to clean the surface.
Since an inert gas is used, organic dirt and oxides can be removed, but a desired fine unevenness cannot be obtained.
An object of the present invention is to provide a method for producing a coated member having no problem and having high adhesion between a substrate and a coating film and having a smooth surface.

[0007]

Means for Solving the Problems The present inventors have discovered and confirmed that fine irregularities can be formed by previously applying ion bombardment to the surface of a substrate to be coated, and have completed the present invention. In other words, the method for producing a coated member of the present invention comprises the step of forming a concavo-convex forming gas containing at least one kind of argon, helium and hydrogen and a concavo-convexity promoting gas containing one or more kinds of nitrogen, carbon and oxygen on the surface of the base material to be coated. Ion bombardment using a mixed gas of the above and a first step of forming a projection having an average height in the range of 10 to 100 nm and an average width in the range of 10 to 300 nm to form an uneven surface; A second step of forming a coating film thereon.

[0008] Since the interface between the base material and the coating film is an uneven surface having a convex portion of a predetermined height and width, the bonding between the two is strong and the coating member is more integrated.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a coated member according to the present invention comprises a first step of forming an uneven surface by ion bombardment of the surface of a substrate, and a second step of forming a coating film on the obtained uneven surface. Having. The substrate according to the present invention constitutes various parts such as a substrate, a sliding member, and a structural member, and a part of an apparatus, and is formed of metal or the like. Examples of the metal forming the substrate include iron-based metals such as steel, metals such as titanium, aluminum, copper, and magnesium, or alloys of these metals, cermets, ceramics, and resins.

In the first step, the surface of the base material to be coated contains in advance a rare gas such as argon, helium, or neon, and a concavo-convex forming gas containing at least one kind of hydrogen, and at least one kind of nitrogen, carbon and oxygen. This is a step of forming a projection having an average height in the range of 10 to 100 nm and an average width in the range of 10 to 300 nm by ion bombardment using a mixed gas with the unevenness promoting gas to form an uneven surface.

As the irregularity forming gas, a rare gas (He, A
r, Ne, etc.) or H ₂ gas.
Examples of the unevenness promoting gas include a nitrogen atom-containing gas such as N ₂ and NH ₃ , a carbon source such as CH ₄ and C ₂ H ₂ and a contained gas, O ₂ , CO 2
_Two gases or the like can be used. In the mixed gas obtained by mixing these gases, the value of the unevenness promoting gas / the unevenness forming gas is 0.
It is preferably from 0001 to 0.5. This value corresponds to the flow ratio and volume ratio of the unevenness forming gas and the unevenness promoting gas. If the value is less than 0.0001, the formation of the unevenness is slow, and if it exceeds 0.5, the reaction layer is more easily formed than the formation of the unevenness.

Preferably, the pressure of the mixed gas is about 0.001 to 20 torr, the discharge output density is 0.1 to 10 W / cm ² , and the processing time is about 30 to 60 minutes. More specifically, a substrate to be processed is placed in a closed container, and the pressure in the closed container is set to about 10 ^{-3 to} 20 torr. Pressure is 10 ^-3 to
If it is less than rr, the material to be treated cannot be sufficiently heated. When the pressure exceeds 20 torr, the material to be treated can be heated, but it is difficult to form fine irregularities.

Next, the mixed gas as a processing gas is introduced into the container. In this state, ion bombardment is applied. Glow discharge or an ion beam can be used as a means for applying ion bombardment. Discharge output 0.1 to 10 W / cm
^{In step 2} , if ion bombardment is performed for a treatment time of 30 to 60 minutes, uniform and fine nano-order irregularities are formed. The temperature at which the hardness of the material to be treated does not decrease during ion bombardment (200
C. or higher is preferred. ), Uniform and fine nano-order irregularities are formed.

According to the first step, the average height is in the range of 10 to 100 nm and the average width is in the range of 10 to 300 n on the substrate surface.
An uneven surface in the range of m is formed. The convex portion is formed in a shape such as a hemisphere or a cone. Here, the height of the convex portion is the distance from the bottom to the vertex of the convex portion when the convex portion is regarded as a hemisphere, and the width of the convex portion is when the convex portion is regarded as a hemispherical portion. The distance in the horizontal direction corresponds to the maximum diameter of the bottom of the hemispherical convex portion (the diameter when the bottom shape of the convex portion is a perfect circle, and the major axis diameter when the bottom shape of the convex portion is an ellipse).

The reason why the average height is in the range of 10 to 100 nm is that if the average height is less than 10 nm, a mechanical anchor effect cannot be obtained and the adhesion is insufficient. On the other hand, if it exceeds 100 nm, a smooth film cannot be obtained. Note that a more preferable range of the average height is 20 to 70 nm, and the adhesion is further improved. The reason why the average width is in the range of 10 to 300 nm is that if the average width exceeds 300 nm, the anchor effect is reduced and the adhesion is reduced. If it is smaller than 10 nm, the anchor effect becomes small. The size of the projection cannot be measured by a conventional surface roughness meter (probe method). For this reason, the size and width of the convex portion are determined by microscopic measurement such as SEM (scanning electron microscope) observation and AFM (atomic force microscope).

Even if the size of the projection is predetermined, if the area of the projection is small, no effect can be obtained on the adhesion of the film. As for the area ratio of the convex portion to the uneven surface, assuming that the area of the uneven surface is 100%, the area occupied by the convex portion is preferably 30% or more. If it is 30% or more, the adhesion of the film becomes high. More preferably, when the content is 50% or more, the adhesion is further improved.

As the method of forming the coating film in the second step, the coating film can be formed by ion plating (arc, hollow cathode method, etc.), sputtering, vacuum deposition, plasma CVD, or the like. The formed coating film is firmly adhered because the surface of the substrate is uneven. Further, the obtained coating film has a smooth surface with few irregularities.

After forming the coating film by performing the second step, there is no particular need for post-treatment such as polishing or lapping the formed coating film. By appropriately performing the first and second steps of the present invention, a smooth coating layer that does not require polishing or lapping is formed. The coating film covers at least a part of the surface of the base material and adds a function such as corrosion resistance, abrasion resistance, and decorativeness to the surface, and is formed by various coating methods. It consists of a film and a carbon-based film. Specifically, chromium, nickel, tungsten, and the like are used as the metal film for forming the coating film, and the ceramic film is a group IV to IV of the periodic table.
A nitride film, a carbide film, an oxide film, a boride film, etc., and a film of AlN, BN, SiN, SiC, etc. made of a group VI element or a composite element containing one of them are used. (Diamond-like carbon), diamond and the like. The coating film may be a combination of two or more of the above films.

The thickness of the coating film is 0.5 μm to 20 μm.
It is preferably set to μm. When the thickness is 0.5 μm or less,
It is difficult to smooth fine irregularities. On the other hand, if the thickness is 20 μm or more, the internal stress of the film increases, and the effect of fine irregularities decreases. When abrasion resistance is imparted to the coating film obtained by the method of the present invention, this coating member can be used for a sliding member requiring abrasion resistance. For example, as a mechanical part with sliding,
Engine parts (pistons, piston rings, valve stems, shim plates, etc.), compressor parts (vanes, shoes, etc.), injection pumps (rotors, plungers, needles, etc.)
Can be used for sliding parts.

[0020]

According to the method for producing a coated member of the present invention,
For the formation of irregularities on the surface of the substrate by the ion bombardment of the first step,
A mixed gas of the unevenness forming gas and the unevenness promoting gas is used. Therefore, an uneven surface having a convex portion having an average height in the range of 10 to 100 nm and an average width in the range of 10 to 300 nm is easily and stably formed on the surface of the base material. Then, in the second step, a coating film is formed on the uneven surface. The bonding area between the base material and the coating film is increased due to microscopic unevenness at the interface. The adhesion strength increases in response to the increase in the bonding area. In addition, since the surface of the substrate is cleaned and activated by forming the uneven surface, a strong coating film is formed. Further, the substrate and the coating film are mechanically connected by the mechanical anchoring effect of the concave portion formed at the boundary of the convex portion, so that a stronger connection can be obtained.

The unevenness of the uneven surface of the substrate is 10 to 100.
Since it is extremely small, ie, nm, the surface of the coating film becomes smooth.

[0022]

【Example】

Example 1 SUS440C was used as a substrate. The surface roughness of the substrate was Rz 0.05 μm. As the ion bombardment gas, only a mixture of argon and hydrogen gas, which is the same as the irregularity forming gas of the present invention, and nitrogen added as the irregularity accelerating gas of the present invention in which the mixing ratio was changed was used. In any case, gas pressure 6 torr
r, 60 at a discharge power density of 0.001 to 2.0 W / cm ²
Went in minutes. Table 1 shows the concavo-convex formation conditions.

The projections shown in Table 1 were formed by this ion bombardment treatment. Thereafter, a hard film made of a DLC-Si film was formed on the surface of the substrate on which the unevenness forming process was performed by a plasma CVD method. The thickness was 3 μm. The adhesion of the hard film was evaluated by a scratch test based on the magnitude of the peeling load of the film. The results are shown in Table 1. In addition, as a result of examining the adhesive force of a film necessary for practical use by a friction test and the like, if an adhesive force of 30 N or more is obtained with steel parts,
No peeling of the film was observed during sliding, and the adhesion required for practical use was determined.

In the scratch test, a load applied when a diamond cone having a vertex angle of 120 ° and a tip of 0.2 mmR is scratched under a load to measure the peeling of the film is referred to as a critical load. The adhesiveness of the hard film is evaluated based on the magnitude of the above. In Table 1, samples 1-1, 1-2 and 1-3 correspond to comparative examples, and samples 1-4 and 1-5 correspond to examples.

[0025] As is clear from Table 1, no protrusion was formed in Sample 1-1. In Sample 1-2, the size of the convex portion was 5 nm, and the adhesion was as low as 12 N. In the sample 1-3 in which the mixing ratio of the gas was 1.0, the adhesion was low because the size of the convex portion was 10 nm or less. In Samples 1-4 and 1-5, the area ratio of the protrusions is as high as 50% or more, and the adhesion is as high as 40N or more. Thus, it is understood that the ion bombardment treatment using a mixed gas obtained by adding the unevenness forming gas of argon + hydrogen gas to the unevenness promoting gas of nitrogen at a mixing ratio of 0.01 or 0.1 is preferable.

[0026]

Example 2 SKH51 was used as a substrate. Also,
The surface roughness of the substrate was Rz 0.05 μm. As the ion bombardment gas, only argon gas and two types of mixed gas obtained by adding methane having a mixing ratio of 0.05 to argon gas were used. Gas pressure 3 torr, discharge output 1.5 to 3.0 W /
Performed in cm ² for 60-240 minutes. The projections shown in Table 2 were formed by this ion bombardment treatment.

Thereafter, a TiN film was formed on the substrate surface at a temperature of 300 ° C. or less by an arc ion plating method. The thickness was 3 μm. Table 2 shows the results of the adhesion evaluation. In Table 2, Samples 2-1 and 2-3 correspond to Comparative Examples, and Sample 2-2 corresponds to Examples. As is clear from Table 2, Sample 2-1 had a height of the convex portion of 1
At 0 nm or less, the width of the projections is small, the area ratio of the projections is small, and the adhesion is low. In Sample 2-3, a large amount of CH4 gas was added, but the formation of unevenness was insufficient and the adhesion was low.

The sample 2-2 of the product of the present invention has a height of the convex portion,
It was found that irregularities were formed in both the width and the area ratio to obtain a mechanical anchor effect, and the adhesion was as high as 40 N.

[0029]

Example 3 A2017 was used as a substrate. Also,
The surface roughness of the substrate was Rz 0.5 μm. As the ion bombardment gas, only helium gas and two types of mixed gas obtained by adding oxygen which is a helium gas and a concavity-promoting gas having a mixing ratio of 0.005 were used. The test was performed at a gas pressure of 2 torr and a discharge output density of 0.3 W / cm ² for 30 minutes. The projections shown in Table 3 were formed by this ion bombardment treatment.

Thereafter, a DLC film was formed on the surface of the substrate by a plasma CVD method. The thickness was 1 μm. Table 3 shows the results of the adhesion evaluation. However, since a soft aluminum alloy was used as the base material, the base material was largely plastically deformed in a normal scratch test, and the peeling load of the film could not be determined. Therefore, the evaluation was performed using a scratch test machine with a small load. In Table 3, sample 3-1 corresponds to a comparative example, and sample 3-2 corresponds to an example. Also in Example 3, by comparing the sample 3-1 with the sample 3-2, the present invention using the mixed gas of the unevenness forming gas and the unevenness promoting gas is different from the sample 3-1 formed only with the unevenness forming gas. It can be seen that the sample 3-2 of Example 3 can achieve a high convex area ratio and the adhesiveness is as high as 40 mN as compared with the sample 3-1 of the comparative example.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideo Tachikawa 41-Cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central R & D Laboratories Co., Ltd. No. 1 Inside Denso Corporation (72) Inventor Hidemi Mori 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Inside (72) Inventor Tsuneaki Minamiguchi 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Stock Association Inside DENSO

Claims (3)

[Claims] An ion-forming method using a mixed gas of a concavo-convex forming gas containing at least one kind of rare gas and hydrogen and a concavo-convexity promoting gas containing at least one kind of nitrogen, carbon and oxygen on a surface of a base material to be coated. A first step of forming a projection having an average height in the range of 10 to 100 nm and an average width in the range of 10 to 300 nm to form an uneven surface, and forming a coating film on the uneven surface And a second step. 2. The method for manufacturing a coated member according to claim 1, wherein the unevenness promoting gas / the unevenness forming gas is 0.0001 to 0.5. 3. The method for manufacturing a covering member according to claim 1, wherein an area of the projections in the uneven surface is 30% or more.