KR20120120471A - Process for production of coated article having excellent corrosion resistance, and coated article - Google Patents

Abstract

The manufacturing method of the coating article excellent in corrosion resistance which coat | covered the hard film which consists of at least 2 layer or more by the physical vapor deposition method on the surface of the base material of an article. The present manufacturing method includes coating a first hard coat on a surface of a substrate, and coating a second hard coat on the surface of the first hard coat, and before applying the second hard coat, the first hard coat And polishing the surface of the film to an arithmetic mean roughness Ra of 0.05 μm or less and a maximum height Rz of 1.00 μm or less.

Description

PROCESS FOR PRODUCTION OF COATED ARTICLE HAVING EXCELLENT CORROSION RESISTANCE, AND COATED ARTICLE}

The present invention relates to a method for producing a coated article requiring corrosion resistance and a coated article, such as a mold, a tool, and an injection molding part used for molding plastic or rubber, for example.

Background Art Conventionally, in molding plastic (resin) or rubber, excellent corrosion resistance is required for articles such as molds and tools used for molding from the corrosive environment caused by the molded material. For example, in the case of injection molding, various additives for improving heat resistance and strength are added to a molded material such as plastic. During the injection molding, the plastic is decomposed by the heating or the heat generation, and the corrosion gas is also generated from the additive, so that the injection molding parts (for example, the screw head or the sealing) are exposed to severe corrosive environment. It becomes a factor, such as a formula and gas baking.

Therefore, as a method of improving the corrosion resistance of various articles used in a corrosive environment, the surface treatment of the said component is generally used. For example, there is a method of improving the corrosion resistance by coating hard chromium plating of a thick film. In addition, hard films such as TiN, CrN, TiCN, etc. coated by physical vapor deposition (hereinafter abbreviated as PVD) or chemical vapor deposition have an excellent corrosion resistance and also have high wear resistance due to high hardness. to be.

For example, after nitriding the surface of an injection molding part, there is a method of improving wear resistance, film adhesion, and the like by coating CrN or TiN film by the arc ion plating method (Patent Document 1). Similarly, in the method of coating the CrN or TiN film, the method of imparting the corrosion resistance by first coating the CrN film having excellent adhesion to the substrate and the corrosion resistance, and then coating the high hardness TiN film in multiple layers (Patent document 2).

Moreover, while improving the film component mentioned above, there is a method of improving the film characteristics by improving the structure. For example, in the field of cutting tools, when coating a hard film on the surface of a tool, droplets that cause crack fracture are removed by performing intermediate ion etching (bombardment treatment) during coating. There is a method of obtaining a smooth film in which voids and pores do not occur (Patent Document 3). And as a method of removing the said droplet, there also exists a method of applying the mechanical process by sandblasting (patent document 4).

Japanese Patent Application Publication No. 2001-150500 Japanese Patent Application Publication No. 2005-144992 Japanese Patent Application Publication No. 2009-078351 European Patent No. 0756019

Employing PVD as the coating means for hard film is effective because the thermal load on the substrate is small. However, many droplets, particles, and the like exist in the coating film coated with PVD. When voids, pores, and pinhole-type gap defects caused by these penetrate into the substrate, in particular, corrosion proceeds severely at the site, which causes premature formulation and gas burn. Therefore, even if it is CrN excellent in corrosion resistance, the hard film of patent document 1 has a subject that the original corrosion resistance cannot be acquired because the above defect exists in a film. Moreover, even if the hard film of the said patent document 2 coat | covers a TiN film on the CrN film, the defect formed once in a CrN film is hard to be covered and invisible.

Therefore, about the hard film of patent documents 1 and 2, the introduction of the ion etching of patent document 3 to the surface can be considered. However, in terms of improving the corrosion resistance, it has not reached the removal of droplets or the like sufficient to exert their effects. When the sand blast of Patent Document 4 is applied, this is a defect processing method only by the grinding action, such as spraying particles onto the film surface, and therefore, it is difficult to obtain a preferable smooth surface in consideration of improvement of corrosion resistance.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a method for producing a coated article and a coated article in which the corrosion resistance of the hard coating is improved.

MEANS TO SOLVE THE PROBLEM This inventor examined the method of suppressing the defect which penetrated toward the base material from the surface about the hard film coat | covered with PVD. As a result, for this suppression, it was found that removing impurities such as droplets on the surface of the coating without leaving as much as possible during the coating step is important for improving the corrosion resistance. In addition, it has also been found that the surface of the film after removal of droplets or the like has a constant surface roughness for improving corrosion resistance. And this invention was reached by realizing the coating structure excellent in corrosion resistance as a coating article.

That is, this invention is a manufacturing method of the coating article excellent in corrosion resistance which coat | covered the hard film which consists of at least 2 layer or more by PVD on the surface of the base material of an article, This manufacturing method coat | covers a 1st hard film on the base material surface. And coating a second hard coat on the surface of the first hard coat, and before the coating of the second hard coat, the surface of the first hard coat has an arithmetic mean roughness Ra of 0.05 μm or less, and also maximum A method for producing a coated article having excellent corrosion resistance, further comprising the step of polishing to a height of Rz 1.00 µm or less.

When the surface roughness of the base material before coating the hard film is A, the surface roughness before polishing the first hard film is B, and the surface roughness after polishing the first hard film is C, the arithmetic mean roughness Ra and the maximum are respectively. It is preferable that height Rz satisfy | fills following formula 1-3.

For Ra and / or Rz, A <C <B ??? Equation 1

For Ra, C / B <0.4 ??? Equation 2

For Rz, C / B <0.1 ??? Equation 3

Further, the surface of the first hard film has a number density of a peak and a grain of 50 nm / mm ² or less in the cross-sectional curve obtained by the cross-sectional measurement, each having a distance from the average line of 50 nm or more. It is desirable to polish as much as possible.

It is preferable that a 1st and / or a 2nd hard film is chromium nitride. Moreover, it is preferable that these hard films are chromium nitride containing 1 type, or 2 or more types of elements chosen from Mo, Nb, W, Si, and B.

In this case, the second hard film is a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N (where the subscript indicates an atomic ratio of Cr and element X), where X is It is 1 type, or 2 or more types of elements chosen from Mo, Nb, and W, and it is preferable that a is 0.1-0.2. Or X is 1 type, or 2 or more types of elements chosen from Si and B, and it is preferable that a is 0.03-0.10.

After the step of coating the second hard film, it is preferable to polish the surface of the second hard film. Further, the surface roughness of the base material before coating the hard film is A, the surface roughness before polishing the first hard film is B, the surface roughness after the first hard film is polished C, and the second hard film is polished. When surface roughness is made into D, it is preferable that each arithmetic mean roughness Ra and the maximum height Rz satisfy | fill following formula 1-3.

For Ra and / or Rz, A <C <D <B ??? Equation 1

For Ra, C / B <0.4 ??? Equation 2

For Rz, C / B <0.1 ??? Equation 3

The physical vapor deposition method is preferably an arc ion plating method, and the coated article is preferably a part for injection molding or a metal mold.

In addition, the coated article of the present invention is obtained by the above-described manufacturing method of the present invention, and is a coated article in which a hard film is coated on the surface of an article by physical vapor deposition, wherein the hard coat is a first article coated on the substrate surface. 1 micrometer or more of long diameter which consists of at least 2 layer or more of a 2nd hard film coat | covered directly on the hard film, and the 1st hard film polished, and across the interface of a 1st hard film and a 2nd hard film. It is a coating article excellent in corrosion resistance that the number of droplets per 50 micrometers of interface lengths at the time of sectional structure observation is less than two (containing 0).

It is preferable that a 1st and / or a 2nd hard film is chromium nitride. And it is preferable that these hard films are chromium nitride containing 1 type, or 2 or more types of elements chosen from Mo, Nb, W, Si, and B. In this case, the second hard film is a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N (where the subscript indicates an atomic ratio of Cr and element X), where X is It is 1 type, or 2 or more types of elements chosen from Mo, Nb, and W, and it is preferable that a is 0.1-0.2. Or X is 1 type, or 2 or more types of elements chosen from Si and B, and it is preferable that a is 0.03-0.10. Moreover, it is preferable that the surface of a 2nd hard film is polished. Moreover, it is preferable that the physical vapor deposition method is an arc ion plating method, and it is preferable that the coating article of this invention is a component or metal mold | die for injection molding.

According to the present invention, by optimally polishing the surface of the first hard film during the coating of the hard film, after coating the second film, very few defects penetrating toward the substrate are exhibited, thereby exhibiting excellent corrosion resistance. do. Preferably, the second hard film can be further improved in corrosion resistance and high hardness by making the structure of the second hard film fine, so that the coated article can be made excellent in corrosion resistance as well as wear resistance. Therefore, the present invention is useful for the production of injection molding parts, tools and molds exposed to corrosive environments.

1A is an example of the cross-sectional curve of the 1st hard film of sample No. 1 of the example of this invention. The arrow represents the average line.
1B is an example of the cross-sectional curve of the 1st hard film of sample No. 8 of a comparative example. The arrow represents the average line.
2A is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 1 of the example of the present invention.
2B is a micrograph of the surface of a hard film showing the result of the corrosion test performed on sample No. 2 of the example of the present invention.
2C is a micrograph of the surface of a hard film showing the result of a corrosion test (immersion time is 10 hours) performed in Sample No. 5 of the comparative example.
FIG. 2D is a photomicrograph of the surface of a hard film showing the result of a corrosion test (immersion time 10 hours) performed in Sample No. 7 of a comparative example.
2E is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 9 of a comparative example.
2F is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 10 of the comparative example.
3A is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 12 of the example of the present invention.
3B is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 15 of the example of the present invention.
3C is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 23 of the example of the present invention.
3D is a micrograph of the surface of a hard film showing the result of the corrosion test performed on sample No. 27 of the example of the present invention.
3E is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 28 of the example of the present invention.
3F is a micrograph of the surface of a hard film showing the result of a corrosion test performed on sample No. 32 of the example of the present invention.
4A is a scanning electron micrograph showing the fracture surface structure of the hard film of sample No. 12 of the example of the present invention. The upper part of the photograph is the second film, and the lower part is the first film.
4B is a scanning electron micrograph showing the fracture surface structure of the hard film of sample No. 11 of the example of the present invention. The upper part of the photograph is the second film, and the lower part is the first film.
5 is a schematic view of a film forming apparatus used in the embodiment.
6A is a microstructure photograph of a hard film cross section of Sample No. 1 of the example of the present invention. It is a base material, a 1st film, and a 2nd film from the bottom.
6B is a microstructure photograph of the hard film cross section of Sample No. 8 of the comparative example. It is a base material, a 1st film, and a 2nd film from the bottom.

MEANS TO SOLVE THE PROBLEM This inventor discovered that local corrosion generate | occur | produces from the unevenness | corrugation which started from the droplet, particle, etc. on a 1st hard film, while studying the method of suppressing corrosion of a film. In addition to dividing the hard film into the first hard film and the second hard film, and covering the multilayer film with the first hard film, the first hard film is not covered with the second hard film as it is. It was found that polishing was carried out to smooth to a constant surface roughness, and a second hard film was coated thereon, thereby significantly improving the corrosion resistance of the entire film, and also finding a film structure excellent in corrosion resistance. Hereinafter, it demonstrates in detail.

In the production method of the present invention, the polishing of the first hard coating on the surface can be made smooth by removing droplets, particles, and the like, and at the time of coating the second hard coating, It is because it can coat | cover so that fine unevenness | corrugation can be filled, and can significantly improve the corrosion resistance of the whole film.

The surface of the 1st hard film coat | covered by the manufacturing method of this invention can improve corrosion resistance by smoothing the film surface so that it may become a constant surface roughness. That is, arithmetic mean roughness Ra in the surface roughness prescribed | regulated to JIS-B-0602-2001 can be made into 0.05 micrometer or less, and maximum height Rz can be improved to 1.00 micrometer or less, and corrosion resistance can be improved. Moreover, it is preferable that a 2nd hard film also exists in the range of the same surface roughness.

In order to make the surface of a 1st hard film the preferable surface roughness mentioned above, smoothing of a film surface is inadequate and grinding | polishing-resistance of a film is inferior by the grinding | polishing effect | action by ion etching, sandblasting (shot blasting), etc. have. Therefore, in order to remove droplets, particles, and the like reliably and to make the surface smooth, it is preferable to employ the following polishing method.

(1) In the case of finishing a mechanical part, as a polishing means for precisely finishing the part surface so as to have an accurate uniform surface, for example, using a platen to sandwich a wrap agent between the hard films. To grind hard film by sliding movement

(2) A method of polishing the surface of the hard film with an abrasive cloth containing an abrasive such as diamond paste

(3) A so-called AERO LAP (Syama Shita Works), which uses a polishing agent having a diamond particle and a humidity to slide at a high speed on a film coated on a substrate, and polish by the generated frictional force. Polishing method)

(4) Polishing method by so-called smap (mirror shot machine manufactured by Kamei Iron Works Co., Ltd.) etc. which grinds by spraying an abrasive with elasticity and adhesiveness without using air.

Furthermore, more preferable smoothing can be realized by performing diamond paste polishing of 3 占 퐉 or less after such treatment. Moreover, in order to improve corrosion resistance, it is preferable to also smooth the surface image of a 2nd hard film by the same grinding | polishing method.

A coated article in which a hard film is coated by PVD on the surface of a base material of the article by the above-described manufacturing method, wherein the hard film is directly coated on the first hard film coated on the surface of the base material and the polished first hard film. It consists of at least 2 layers or more of the 2nd hard coating, and the number of droplets with a diameter of 1 micrometer or more across the interface of a 1st hard coating and a 2nd hard coating per 50 micrometers of interface length at the time of sectional structure observation is less than two. The coated article of the present invention excellent in corrosion resistance (including 0) can be obtained.

If coarse droplets are present, internal defects such as voids are formed between the films deposited on the upper surface. This defect leads to corrosion. Therefore, smoothing by polishing in the middle of the hard film forming step is effective in preventing communication of internal defects in the depth direction of the hard film.

In the present invention, the average number of droplets having a long diameter of 1 μm or more across the interface between the first hard film and the second hard film having a smoothed interface per 50 μm of the interface length when the cross-sectional structure is observed is less than 2 (including 0). It was prescribed as. This is because the presence of droplets having a diameter of less than 1 μm and the presence of about two particles per 50 μm, even if the length of the liquid crystal is 1 μm or more, have no significant effect on the corrosion resistance.

In order to smoothly adjust the surface roughness of the first and / or second hard film, it is preferable to smoothly polish the surface roughness of the substrate before the coating. Specifically, the surface roughness of the substrate before coating the hard film is A, the surface roughness before polishing the first hard film is B, the surface roughness after polishing the first hard film is C, and each arithmetic mean roughness Ra and It is preferable that the maximum height Rz satisfies the relationship A <C <B.

In the present invention, it is important to smooth the surface of the first hard film, and even when polishing the second hard film, if the surface roughness after polishing the second hard film is D, then A <C <D <B It is desirable to satisfy the relationship.

By smoothing the surface of the substrate, it is possible to suppress a film defect due to irregularities on the surface of the substrate. The coating defect directly above the substrate causes a significant corrosion of the substrate directly, and it is more preferable that the coating defect of the coating on the side close to the substrate is small. Therefore, it is preferable to make the surface roughness of the first hard film smooth, rather than the surface roughness of the second hard film after polishing, and to make the surface roughness of the base material before coating most smooth.

In addition, with respect to the first hard film, when polishing and removing droplets and the like on the surface during the coating, the degree of removal, that is, the surface roughness C after polishing, represents Ra as C / B relative to the surface roughness B before polishing. It is preferable to finish Rz so that C / B may be less than 0.1 so that it may become less than 0.4. By satisfy | filling these formulas, the defect of a hard film can be reduced more.

When the uneven portion is present on the surface of the first hard film coated by the production method of the present invention, local corrosion easily occurs. And excellent corrosion resistance can be obtained by reducing this uneven part. Therefore, in the cross-sectional curve by the cross-sectional measurement of the first hard film, the number density of the calculations [convex parts] and the grains [concave parts] whose distance from the average line is 50 nm or more is 50 pieces / mm, respectively. It is preferable to grind so that it may become ² or less.

And the average line was the center line of the calculation and the grain in a cross-sectional curve, and the number of peaks which exist in 50 nm or more from the center line was investigated, respectively, and each number density was measured.

It is preferable that the 1st and / or 2nd hard coating coat | covered by the manufacturing method of this invention is chromium nitride which is excellent in corrosion resistance by a film itself. In addition, a chromium nitride means that the amount of chromium is 50 atomic% or more in the metal (including semimetal) part.

Moreover, it is preferable that the said 1st hard film and / or the 2nd hard film is a chromium nitride containing 1 type, or 2 or more types of elements chosen from Mo, Nb, W, Si, and B. By adding Mo, Nb, and W in the film, the hardness is improved and the wear resistance is improved. Above all, in order to have an advantage in maintaining the toughness and adhesion of chromium nitride itself, a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N (where the subscript is represented by Cr and element X Represents an atomic ratio), and X is one or two or more elements selected from Mo, Nb, and W, and a is preferably 0.1 to 0.2.

And by adding Si and B in a film, a film becomes fine and high hardness. Preferred film hardness is not less than 2000HV _{0 .025.} And since a coating | film | coat is refine | miniaturized, corrosion resistance improves more. When a reinforcing material such as glass fiber is added to the formed material, the hard film is likely to cause corrosion due to abrasion. Therefore, in addition to the improvement of abrasion resistance, abrasion corrosion can also be suppressed by giving high hardness to a hard film. In order to exert such an effect and not reduce the toughness and adhesion of the chromium nitride itself, the chromium nitride represented by the component composition of (Cr _{1 - a} X _a ) N (where the subscript is formed of Cr and element X X represents one or two or more elements selected from Si and B, and a is preferably 0.03 to 0.10.

The coating means used by the manufacturing method of this invention requires the physical vapor deposition method of the high film adhesiveness of the hard film to coat | cover. For example, although there are a sputtering method and an arc ion plating method, especially the arc ion plating method with high film adhesiveness is especially preferable.

Example 1

An arc ion plating apparatus was used for the coating means of a hard film. The schematic diagram of the film-forming apparatus is shown in FIG. The film formation chamber 2 includes a plurality of arc discharge evaporation sources 3, 4, 5 for mounting various targets (cathodes) 1, and a substrate holder 6 for mounting the substrate 7. There is a rotating mechanism 8 under the base holder 6, and the base 7 rotates and revolves through the base holder 6. And when the base material 7 opposes various targets, the film by the said target is coat | covered. And the target used in the present Example is a metal target produced by the powder metallurgy method.

In the evaporation source 3 to 5, a target constituting a metal component of the hard film and a target for metal ion etching were appropriately mounted. The substrate used was a steel equivalent to JIS-SKD11, which had been refined to 57 to 60 HRC, and the surface of the substrate was polished to an arithmetic mean roughness Ra of 0.01 µm and Rz 0.07 µm before the first hard film was coated on the substrate. It was. This was degreased and washed and fixed to the substrate holder 7. And the base material was heated to 500 degreeC vicinity by the overheating heater which is not shown in the chamber 2, and hold | maintained for 50 minutes. Next, Ar gas was introduced, a bias voltage of -60V was applied to the substrate, and plasma cleaning treatment (Ar ion etching) was performed for 30 minutes. Subsequently, a bias voltage of -800 V was applied to the substrate, and Ti metal ion etching was performed for about 20 minutes. Subsequently, nitrogen gas was introduced, and a bias voltage of -150 V was applied to the substrate to form a hard film to form various nitrides under conditions of a substrate temperature of 500 ° C. and a reaction gas pressure of 3.0 Pa.

Table 1 shows the prepared samples. The hard film is CrN. Sample No. 1, which is an example of the present invention, is a means for removing the substrate from the chamber after the first CrN is coated and polishing the surface in the meantime (hereinafter, abbreviated to intermediate surface treatment). Shiki Kaisha Yamashita Works Co., Ltd., using an aero wrap device (AEROLAPYT-300)], and then polished and polished with a 1 μm diamond paste, followed by a SMAP treatment (manufactured by a joint venture Kamei Iron Works, mirror surface shot machine SMAP-). Use of type II). After degreasing and washing, the mixture was returned to the chamber again, followed by Ar ion etching and Ti metal ion etching to cover the second CrN to complete the hard coating.

And about sample No.2-7, after each intermediate surface treatment below, 2nd CrN was coat | covered by the method similar to sample No.1. Sample No. 2 performed the intermediate surface treatment only by the said aero wrap process. In the intermediate surface treatment of Sample No. 3, the SMAP treatment was omitted in the treatment of Sample No. 1. For the intermediate surface treatment of Sample No. 4, a nylon nonwoven fabric (manufactured by Bellstar Abrasive Materials Co., Ltd., polishing pads # 1500 to # 3000) coated with an abrasive was used.

In sample No. 5 as a comparative example, a shot blast treatment (projection material: # 150 alumina) was performed instead of the intermediate surface treatment of the present invention. Sample Nos. 6 and 7 correspond to Patent Document 4. That is, instead of the intermediate surface treatment of the present invention, sandblasting treatment (projection material: 400-600 yarns) was performed respectively.

Sample Nos. 8 and 9 which are comparative examples correspond to Patent Document 3. That is, after coating 1st CrN, it extracts from a chamber similarly to sample Nos. 1-5, returns to a chamber as it is, without performing intermediate surface treatment (however, No. 9 only performs degreasing washing | cleaning), and 2nd Before coating CrN, Ar ion etching and Ti metal ion etching are performed similarly to a base material.

Sample No. 10 which is a comparative example corresponds to Patent Documents 1 and 2, and formed into a film without being drawn out from the chamber.

And finally, the outermost surface of the said sample No.1-10 was polished with the diamond paste.

For these samples, the surface roughnesses of the first and second CrNs were measured and the corrosion resistance was evaluated. Each evaluation test method is shown below.

(Surface roughness measurement)

In accordance with JIS-B-0602-2001, arithmetic mean roughness Ra and maximum height Rz were measured from the roughness curve. Measurement conditions are evaluation length: 4.0 mm, measurement speed: 0.3 mm / s, and cutoff value: 0.8 mm. And about the 1st coating surface, the calculation of the calculation and the number density of the grains which this invention defined were measured by the cross section curve based on the above-mentioned standard. Measurement conditions are evaluation length: 1.0 mm, measurement speed: 0.15 mm / s, (lambda) s value: 0.8 mm. Moreover, in the cross-sectional curve of 1.0 mm in length and width from the center of a film surface, the recessed part (curve) concave 50 nm or more from the average line and the iron part (calculation) which protruded 50 nm or more from the average line were counted. And the average value obtained by repeating this operation 3 times was multiplied by the number of each length and width, and was made into the number density. 1A and 1B show typical cross-sectional curves of Sample Nos. 1 and 8, respectively.

(Corrosion resistance evaluation test)

Corrosion gases such as halogen gas generated during actual injection molding were simulated, and a test was conducted in which the sample was immersed in a 10% sulfuric acid aqueous solution for 20 hours. The temperature of the said aqueous solution was 50 degreeC, and it masked except the surface by which the test piece was coated according to JIS-G-0591-2007. And after immersion, the weight loss by the corrosion was recorded, and the formula (pit) which appears on the surface was observed. The area ratio of corrosion with respect to the test surface was evaluated by the micrograph (magnification: 8 times).

Table 1 shows the above test results. And in Table 2, the relationship between the base material before a hard film is coat | covered, and the surface roughness Ra and Rz of a 1st, 2nd hard film is shown. And about the film surface after the corrosion resistance evaluation test, it is shown to FIG. 2A-FIG. 2F (the part shown in the light color identified as a sphere in a figure is a formula).

[Table 1]

[Table 2]

From Tables 1 and 2, it can be seen that the hard film satisfying the production method of the present invention has the smoothest surface roughness on the surface of the film and is excellent in corrosion resistance. And the coating surface after this corrosion resistance evaluation test is a grade with which the formula of extremely small diameter is confirmed like FIG. 2A-FIG. 2F.

In contrast, the hard coating of Sample No. 5 to 7 subjected to shot blasting and sand blasting treatment has a large surface roughness due to roughening of the surface, and has a very poor corrosion resistance. It is understood that the hard coatings of Sample Nos. 8 and 9 had the most smooth surface, but the corrosion resistance was remarkably inferior, and the improvement of the corrosion resistance was insufficient for the removal of the macro particles by ion etching. In addition, Sample No. 10 in which a hard film was formed consistently is inferior in corrosion resistance of the hard film. As shown in FIG. 2F, the coating surface after the corrosion resistance evaluation test of these samples has caused significant corrosion (sample No. 5 to 7 and the surface when 10 hours have elapsed). In particular, for sample No. 5 to 7, it was confirmed that the corrosion time was already significantly corroded although it was 10 hours shorter than other samples.

[Example 2]

According to the film-forming conditions similar to the sample No. 1 of Example 1, the various samples which changed only the kind of the hard film were produced. The details are as shown in Table 3. And the hardness and corrosion resistance of the film surface were evaluated. Hardness was measured for hardness HV _{0 .025} of the film surface by a micro Vickers tester, according to JIS-Z-2244. The test load is 0.2452 N. Arithmetic mean roughness Ra, maximum height Rz, and the number of uneven | corrugated defects were measured from a roughness curve according to JIS-B-0602-2001 similarly to Example 1 about surface roughness and uneven | corrugated defect density of a hard film. Corrosion resistance evaluation test is the same conditions as Example 1 except the immersion time being 10 hours. These test results are shown in Table 3. About the film surface after the corrosion resistance evaluation test, it is shown to FIG. 3A-FIG. 3F (the part shown in the light color identified as a sphere in a figure is a formula).

Table 3-1

Table 3-2

From Table 3, No. 11-21 and 28-34 are the outstanding balance of the outstanding corrosion resistance and high hardness especially in sample No. 11-34 which satisfy | fills this invention. And sample Nos. 12-20 and 28-34 have high hardness. 3A to 3F show the surface of the film after the corrosion resistance evaluation tests of Sample Nos. 12, 15, 23, 27, 28, and 32, and no noticeable formula was observed in Samples Nos. 12, 15, and 32. FIG.

Moreover, the hardness of the sample which added the semimetal element of Si and B to a hard film becomes high, as the structure becomes fine. For example, in the sample No. 12 in which Si and B were added to the second hard film of sample No. 11, the structure thereof was refined and the film hardness was improved.

4A and 4B are scanning electron micrographs showing the fracture surface structures of Sample Nos. 11 and 12, respectively. It is confirmed that the second hard film of Sample No. 11 has a columnar structure, and the structure of the second hard film of Sample No. 12 is miniaturized.

[Example 3]

In order to find the factor of corrosion resistance improvement, the cross-sectional observation was performed in multiple visual fields with respect to the sample of the example of this invention obtained in Example 1 and Example 2. In addition, the same observation was performed for the No. 8 which was not polished as a comparative example.

As a typical example, the microstructure photograph by the scanning electron microscope in the cross-sectional observation of sample No. 1 and comparative example No. 8 of this invention example is shown to FIG. 6A and FIG. 6B.

As shown in Fig. 6A, in Sample No. 1 of the present invention, coarse droplets of 1 µm or more on the interface were not confirmed.

In addition, in all the samples of the example of this invention, it was the form similar to the sample No. 1 of the example of this invention, and the droplet of 1 micrometer or more was one or less per 50 micrometers of interface lengths. Moreover, in the example of this invention, it was confirmed that the droplet itself which exists in an interface has removed or polished and comprises the smooth surface which does not cross an interface.

On the other hand, in the sample No. 8 of the comparative example with poor corrosion resistance, the coarse droplet of 1-2 micrometers across the interface of a 1st hard film and a 2nd hard film confirmed 4 per 50 micrometers of interface lengths at the time of sectional structure observation. It became. If coarse droplets exist, internal defects such as voids are formed between the films deposited on the upper surface. This defect promotes corrosion.

In the example of the present invention, it is understood that the influence of the coarse droplets can be eliminated by the polishing treatment, whereby the corrosion resistance is improved.

[Industrial applicability]

The present invention provides a metal injection molding (MIM) by adjusting molds and tools for molding plastics and rubbers, parts for injection molding, and other components, for example, coating components and the like, and also providing mold release properties with the molding materials. It can also be applied to a metal mold and various mechanical parts.

1: target
2: deposition chamber
3: evaporation source
4: evaporation source
5: evaporation source
6: substrate holder
7: description
8: rotary mechanism

Claims (19)

A method for producing a coated article having excellent corrosion resistance, wherein a hard film composed of at least two layers is coated on a substrate surface of an article by physical vapor deposition.
In the above manufacturing method,
Coating a first hard film on the surface of the substrate,
Coating a second hard film on the surface of the first hard film
Including,
Before the coating of the second hard coating, further comprising grinding the surface of the first hard coating to an arithmetic mean roughness Ra of 0.05 μm or less and a maximum height Rz of 1.00 μm or less. Method of preparation. The method of claim 1,
When the surface roughness of the base material before coating the first hard film is A, the surface roughness before polishing the first hard film is B and the surface roughness after polishing the first hard film is C. Method for producing coated article excellent in corrosion resistance, where arithmetic mean roughness Ra and maximum height Rz satisfy the following formulas 1 to 3:
For Ra and / or Rz, A <C <B ??? Equation 1
For Ra, C / B <0.4 ??? Equation 2
For Rz, C / B <0.1 ??? Equation 3. The method according to claim 1 or 2,
In the polishing step, the surface density of the first hard film is 50 nm / mm in the number density of the peaks and grains each having a distance from the average line of 50 nm or more in the cross-sectional curve by the cross-sectional measurement. The manufacturing method of the coating article excellent in corrosion resistance grind | polishing so that it may become ² or less. 4. The method according to any one of claims 1 to 3,
The first hard film and / or the second hard film are chromium nitrides, and the method for producing a coated article excellent in corrosion resistance. 5. The method of claim 4,
The first hard film and / or the second hard film is a chromium nitride containing one or two or more elements selected from Mo, Nb, W, Si, and B, and a method for producing a coated article excellent in corrosion resistance. . The method of claim 5,
The second hard film is a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N, wherein X is one or two or more elements selected from Mo, Nb, and W, and a is 0.1? The manufacturing method of the coating article which is 0.2 which is excellent in corrosion resistance. The method of claim 5,
The second hard film is a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N, wherein X is one or two or more elements selected from Si and B, and a is 0.03 to 0.10. , Manufacturing method of coated article excellent in corrosion resistance. 8. The method according to any one of claims 1 to 7,
After the coating of the second hard film, further comprising grinding the surface of the second hard film. 9. The method of claim 8,
The surface roughness of the substrate before coating the hard coating, the surface roughness before polishing the first hard coating, the surface roughness after polishing the first hard coating, and the second hard coating. When the subsequent surface roughness is D, the arithmetic mean roughness Ra and the maximum height Rz satisfy the following formulas 1 to 3, wherein the method for producing a coated article excellent in corrosion resistance:
For Ra and / or Rz, A <C <D <B ??? Equation 1
For Ra, C / B <0.4 ??? Equation 2
For Rz, C / B <0.1 ??? Equation 3. 10. The method according to any one of claims 1 to 9,
The said physical vapor deposition method is an arc ion plating method, The manufacturing method of the coating article excellent in corrosion resistance. 11. The method according to any one of claims 1 to 10,
The said coating article is a manufacturing method of the coating article excellent in corrosion resistance which is an injection molding component or a metal mold | die. A coated article in which a hard film is coated on the surface of an article by physical vapor deposition, wherein the hard coat includes a first hard coat coated on the surface of the substrate and a second hard coat coated directly on the polished first hard coat. The droplet which consists of at least 2 layer of the above, and the droplet of 1 micrometer or more of long diameter which spans the interface of the said 1st hard film and the said 2nd hard film, per 50 micrometers of interface lengths at the time of cross-sectional structure observation. A coated article having good corrosion resistance, wherein the number is less than two (including zero). The method of claim 12,
The coated article having excellent corrosion resistance, wherein the first hard coat and / or the second hard coat are chromium nitrides. The method of claim 13,
The coated article having excellent corrosion resistance, wherein the first hard coat and / or the second hard coat is a chromium nitride containing one or two or more elements selected from Mo, Nb, W, Si, and B. 15. The method of claim 14,
The second hard film is a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N, wherein X is one or two or more elements selected from Mo, Nb, and W, and a is 0.1? A coated article having excellent corrosion resistance of 0.2. 15. The method of claim 14,
The second hard film is a chromium nitride whose component composition is represented by (Cr _{1 - a} X _a ) N, X is one or two or more elements selected from Si and B, and a is 0.03 to 0.10. , Coated article excellent in corrosion resistance. 17. The method according to any one of claims 12 to 16,
The coated article having excellent corrosion resistance, wherein the second hard coat has a polished surface. The method according to any one of claims 12 to 17,
The said physical vapor deposition method is an arc ion plating method, The coating article excellent in corrosion resistance. 19. The method according to any one of claims 12 to 18,
The coated article having excellent corrosion resistance, wherein the coated article is a component or a mold for injection molding.

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