JPH11217666A - Nitrogen-containing cr film, its production and machine member having this film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nitrogen-contg. Cr film excellent in wear resistance, seizure resistance and wear resistance. SOLUTION: In a nitrogen-contg. Cr film, CrXx NY crystals, per 100 atoms, contg. 50 to 99 chromium atomic and 50 to 1 nitrogen atoms are scattered. This film is formed by sputtering chromium in a nitrogen atmosphere. Furthermore, at the time of executing the sputtering, ion bombarding treatment is executed. Moreover, the surfaces of friction and abrasion parts of machine members, particularly motor bicycles, motor tricycles, motor waggons or the like are provided with the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrogen-containing Cr film, a method for producing the same, and a machine member having the film.

[0002]

2. Description of the Related Art Many mechanical members such as molds are used under severe conditions. The characteristics required of these mechanical members are excellent in abrasion resistance, excellent corrosion resistance, It has excellent seizure properties.

In order to impart such characteristics, various surface treatments are usually applied to SKD (tool steel) as a base material of such mechanical members. One of them is hard chrome plating. Hard chrome plating has an average surface hardness of H
Although it is as high as v1000-1100, hexavalent chromium contained in the treated wastewater causes water pollution. In addition, there was a problem in adhesion between the plating film and the base material.

Further, when a single-layer Cr film is formed on the surface of a base material of a machine member by a PVD processing method, although the adhesion between the base material and the film is excellent, the hardness of the film is Hv500-500.
There were problems such as a low of 600.

Further, mechanical parts such as friction and wear parts used in engines and transmissions of motorcycles and four-wheeled vehicles are subject to repeated contact and impact with high-speed rotating bodies. Characteristics such as toughness, high surface hardness and low coefficient of friction are required.

[0006] These parts are generally made of low-carbon steel or medium-carbon steel, and are subjected to surface treatment such as carburizing, quenching, nitriding, etc. in order to impart the above characteristics.
Further, hard chromium plating, nickel-phosphorus plating, shot peening, thermal spraying of various metals, and the like are performed to improve wear resistance, seizure resistance, and lubricity.

However, due to the recent weight reduction and increase in engine output, they have been used in more severe environments, and the required properties cannot be satisfied by the above-described surface treatment. Further, in order to satisfy the above characteristics, P
Among the VD methods, a TiN film or a CrN film formed by an ion plating method is being used. However, in this method, the processing temperature is as high as 400 ° C. or higher, so that the hardness of the base material is reduced and satisfactory characteristics cannot be obtained. There was a problem.

[0008]

As described above, the conventional surface treatment method for mechanical members and the surface coating obtained by the method had problems in abrasion resistance, corrosion resistance, seizure resistance, lubricity, and the like. However, there is a problem that the life of the member itself is inferior.

The present invention has been made to solve the problems of the conventional surface treatment method and coating film.

[0010]

The nitrogen-containing Cr film of the present invention is characterized in that Cr _X N _Y crystals are scattered.

[0011] The method for producing a film is characterized in that the film is formed by sputtering chromium in a nitrogen atmosphere.

In performing the above sputtering,
An ion bombardment process is performed.

Further, the mechanical member of the present invention is characterized in that a nitrogen-containing Cr coating on which Cr _X N _Y crystals are scattered is formed on the surface.

The above Cr _X N _Y crystal is 5 per 100 atoms.
It is characterized by containing 0 to 99 chromium atoms and 50 to 1 nitrogen atoms.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a coating film according to the present invention;

FIG. 1 is a schematic view of a sputtering apparatus for forming a coating film of the present invention on a mold, wherein 1 is a cylindrical or angular vacuum processing chamber, and 2 is a vacuum processing chamber. A rotary table 3 disposed at the center of the vacuum processing chamber 1; a mold 4 as a member to be processed placed on the rotary table 3 via a jig 5;
Reference numeral 6 denotes a chromium target as an evaporation source disposed so as to surround the die 4 to be processed, 7 denotes a DC sputtering power supply connected to the chromium target 6 respectively, 8 denotes a DC ion bombard connected to the rotary table 3 and A bias power supply 9 is a gas introduction pipe for introducing argon and nitrogen gas into the vacuum processing chamber 1.

In the present invention, vacuum degassing is performed before the sputtering process.

In the present invention, after nitrogen gas and argon gas are introduced into the vacuum processing chamber 1 through the gas introduction pipe 9, chromium is sputtered on the surface of a member to be processed, for example, a mold, and the mold is processed. As a Cr film containing nitrogen on the surface, 50 to 99 chromium atoms per 100 atoms and 50
A film is formed in which Cr _X N _Y crystals containing 窒 素 1 nitrogen atom are interspersed. At the time of the sputtering, it is preferable to keep the distance between the target and the material to be processed at, for example, 70 mm in order to make the thickness of the film uniform and to maintain the temperature of the member to be processed at or below the tempering temperature.

In the present invention, an ion bombardment treatment is performed as required before the sputtering process,
In addition, the process temperature is set to less than 300 ° C., the treatment time is determined according to a predetermined thickness of the film, and the structure of the film is adjusted by changing the pressure and the bias voltage during the process. When the process temperature is 300 ° C. or higher, the base material itself is softened. Therefore, the temperature is preferably as low as possible in this treatment. However, it is not practically preferable to perform the treatment at room temperature or lower because it is difficult to secure adhesion.

The thickness of the coating is 100 μm at the maximum.
It is preferable that

When the chemical composition of the film on the surface was examined by EPMA, the ratio of Cr72, N28 and Cr52, N48 was shown. Regarding the properties of the film, seizure resistance,
The wear resistance, coefficient of friction, adhesion, etc. were investigated.

(Comparative example)

In Comparative Examples 1 and 2, an ion-plated TiN film and a film of electrolytic hard chromium plating were used.

The seizure resistance was measured using a Fabry tester as shown in FIG. That is, the diameter is about 6.
A test pin 10 carburized, quenched and tempered on a 4 mm SCM 415 was coated with the coating of the present invention having a thickness of 6 μm.
The intermittent operation was performed at 0 Kgf constant. The intermittent operation is ON for 2 seconds, OFF for 10 seconds, a sliding speed of 0.1 m / sec, and no lubrication. As an evaluation method, the number of intermittent operations until the film was broken was evaluated as the image sticking property.

Reference numeral 12 denotes a test pin, for example, 30
A driving machine 13 rotates at 0 rpm, and 13 is a shear pin for fixing the test pin 10 to the driving machine 12.

Further, as the wear characteristics, aggressive resistance characteristics were evaluated. Suga type wear tester (NUS-ISO-
(Type 3), a reciprocating motion wear test was performed using a # 400 diamond electrodeposited polishing cloth. Base material is S
US440C is mirror finished. The total load of the test piece is 9.8N and the reciprocating stroke length is 60mm
It is. The wear characteristics were evaluated by measuring the wear amount of the sample (× 10 ^−5).
g / cm).

Table 1 shows the results.

[0028]

[Table 1]

In Table 1, for example, the number of times until destruction is 30 <indicates 30 times or more, and 5> indicates 5 times or less.

Further, as an example of a member having the coating of the present invention, a metal mold was subjected to a sputtering treatment.

In the present invention, the ion bombardment treatment
1250 V at 2 × 10 ^-2 torr in an Ar atmosphere
X 0.01 mA for about 40 minutes.

In the sputtering process, the partial pressure of the gas in the atmosphere is set to Ar: 1.2 × 10 ⁻³ torr, N 2: 0.
2 × 10 ⁻³ torr, bias voltage: −90 to −100
V and the processing time was about 100 minutes.

In the present invention, a die was prepared by subjecting tool steel as a base material to a sputtering target treatment under the above conditions.

The above conditions are changed depending on the material, dimensions and shape of the base material. In the case of this embodiment, if the above conditions are not satisfied, the adhesion of the film and the characteristics of the film are inferior.

The film obtained under these conditions has a hardness of H
v = 1700-2000, and the thickness of the obtained film is 1
It was 0 μm.

Table 2 shows a comparative example in use with a conventional mold. The service life is a comparison between the present invention and the conventional mold based on the number of shots of the molded product when the separation of the mold deteriorates when the punch is actually performed.

Table 2 shows the service life of dies and punches of various materials.

[0038]

[Table 2]

Note that, in Table 2, for example, a life magnification of 10
<Indicates that the life was extended 10 times as compared with the conventional one. SKD (HQT) is the SKD of quenching and tempering.
Shows the material.

The coating of the present invention is applied to a motorcycle and
Another embodiment of the present invention applied to a friction and wear part used for an engine such as a wheeled vehicle and a transmission will be described.

As Comparative Examples 3, 4, and 5, an ion-plated TiN film and a CrN film and a film of electrolytic hard chromium plating were used.

The friction coefficient and the seizure resistance were measured using a Fabry tester as shown in FIG. That is, the test pins 10 which were carburized and quenched in SCM415 having a diameter of 6.4 mm and tempered and polished were each 10 μm thick.
A test was conducted in which the tightening load was increased from 0 to 25 kg / sec using a V-block 11 which was provided with the coating of the present invention, carburized and quenched in SCM415, and tempered and polished.
The test was performed in oil, and the coefficient of friction and the seizure resistance at this time were evaluated. Table 3 shows the results.

[0043]

[Table 3]

In consideration of applying the coating of the present invention to a motorcycle shift fork which is a friction and wear part,
A friction wear test was performed to determine the wear amount of the product of the present invention in Comparative Examples 6 to
Compared to 9 At this time, the coating conditions are as follows:
An M415 carburized, quenched and tempered product was finished with a polishing lap to adjust the surface roughness to Ra 0.2, and the coating of the present invention was treated thereon to a thickness of 5 to 10 μm. In a friction and wear test, the friction and wear of a shift fork with a material (shifter) on the other side of an actual motorcycle are examined.
A plate-on-disk test was performed as a friction and wear test, and the surface treatment of a portion corresponding to the shifter was performed by machining, carburizing, and shot blasting.

In the friction and wear test used in the present invention, after the workpiece corresponding to the shift fork is pressed with a predetermined load on the turntable corresponding to the shifter, only the turntable is rotated for a predetermined time, Then, the wear amount of the article to be treated is measured, and this wear amount is evaluated as the amount of decrease in the film thickness of the film on the friction surface of the test piece.

Specifically, after the base material of the article to be treated: SCM415 is carburized, quenched and tempered, it is finished with a polishing lap, the surface roughness is adjusted to Ra = 0.2, and the method of the present invention is further carried out. The nitrogen-containing coating obtained by the above method is applied as a test product with a thickness of 5 μm. The other turntable is machined on the surface in contact with the workpiece, then carburized and shot blasted. The one obtained by was used. The load was 80 kgf, the sliding speed was 13 m / sec, and the time was 20 hours.

As for friction conditions, a durability test was carried out at a maximum load of 80 kgf and a maximum sliding speed of 13 m / sec for 20 hours.

In the evaluation after the test, the amount of wear on the friction surface was evaluated as the amount of decrease in film thickness. Table 4 shows the evaluation results.

[0049]

[Table 4]

In Table 4, hard chromium plating (thickness: 30 μm) was used as Comparative Example 6, TiN (film thickness: 5 μm) made by ion plating was used as Comparative Example 7, and CrN (film was made) was used as Comparative Example 8: Mo-sprayed (film thickness: 100 μm) product was used as Comparative Example 9 (thickness: 6 μm).

[0051]

As described above, according to the mechanical member of the present invention, not only the life of the mechanical member can be greatly extended, but also the releasability is improved, and the effective use of resources and reduction of pollution problems are achieved. Has a great benefit, such as making a significant contribution to

[Brief description of the drawings]

FIG. 1 is an explanatory view of a surface treating apparatus for a mechanical member of the present invention.

FIG. 2 is an explanatory diagram of a Fabry test machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum processing chamber 2 Vacuum pump 3 Rotary table 4 Die to be processed 5 Jig 6 Chromium target 7 Sputter power supply 8 DC bias power supply 9 Gas introduction pipe 10 Test pin 11 V block 12 Drive unit 13 Shear pin

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Yamagata 3-3-104 Nakatakita, Izumi-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor You No 3-3-205 Nakatakita, Izumi-ku, Yokohama-shi, Kanagawa 205 issue

Claims (6)

[Claims] 1. A nitrogen-containing Cr coating characterized by scattered Cr _X N _Y crystals. 2. The nitrogen-containing Cr coating according to claim 1, wherein said Cr _X N _Y crystal contains 50 to 99 chromium atoms and 50 to 1 nitrogen atoms per 100 atoms. 3. A method for producing a nitrogen-containing Cr coating, comprising forming a nitrogen-containing Cr coating in which Cr _X N _Y crystals are scattered by sputtering chromium in a nitrogen atmosphere. 4. The method for producing a nitrogen-containing Cr film according to claim 3, wherein an ion bombardment treatment is performed during the sputtering. 5. Nitrogen-containing Cr in which Cr _X N _Y crystals are interspersed
A mechanical member having a coating formed on its surface. 6. The Cr _X N _Y crystal according to claim 5, wherein said crystal is 5 _x 100 atoms.
6. The mechanical member according to claim 5, comprising 0 to 99 chromium atoms and 50 to 1 nitrogen atoms.