JP5988144B2 - Coated article excellent in corrosion resistance and method for producing the same - Google Patents

Description

  The present invention relates to a coated article requiring corrosion resistance, such as a mold, a tool, and an injection molding part used for molding plastics and rubber, and a method for manufacturing the same.

  Conventionally, in the molding of plastics (resins) and rubbers, excellent corrosion resistance is required for articles such as molds and tools used for molding because of the corrosive environment caused by the molding material. For example, in the case of injection molding, various additives for improving heat resistance and strength are added to a material to be molded such as plastic. During injection molding, the plastic is decomposed by heating or heat generation, and corrosive gas is also generated from the above additives. Therefore, injection molding parts (for example, screw heads, seal rings, etc.) Exposed to severe corrosive environment and susceptible to damage such as pitting and gas seizure.

  As a technique for improving the corrosion resistance of various articles used in a corrosive environment, surface treatment on the component is generally used. For example, there is a technique for improving the corrosion resistance by coating a thick hard chrome plating. Also, hard coatings such as TiN, CrN, and TiCN coated by physical vapor deposition and chemical vapor deposition are effective methods because they have high hardness and wear resistance in addition to their excellent corrosion resistance. .

  For example, there is a technique for improving wear resistance and film adhesion by nitriding the surface of an injection molding part and then coating a CrN or TiN film by an arc ion plating method (Patent Document 1). Similarly, in the method of coating a CrN or TiN film, the CrN film having excellent adhesion and corrosion resistance to the base material is coated first, and then a high-hardness TiN film is coated in multiple layers, thereby improving the corrosion resistance. There is a method of giving (Patent Document 2).

  On the other hand, there is a technique for improving the film properties by improving the structure on the other hand by improving the film components. For example, in the field of cutting tools, when coating a hard film on the tool surface, intermediate ion etching (bombarding) is performed in the middle of the coating to remove droplets that cause crack fracture, and no voids or pores are generated. There is a technique for obtaining a smooth film (Patent Document 3). As a technique for removing the above-described droplets, there is a technique in which mechanical processing by sandblasting is applied (Patent Document 4).

  Adopting the physical vapor deposition method as the means for coating the hard film is effective because the thermal load applied to the substrate is small. However, there are not a few droplets and particles as described above in the film coated by the physical vapor deposition method. When voids, pores, or pinhole-like gap defects due to these penetrate into the base material in particular, the corrosion progresses violently at the site, which causes early pitting corrosion and gas seizure. Therefore, even if it is CrN which was excellent in corrosion resistance, the hard film of patent document 1 has the subject that original corrosion resistance cannot be obtained because the said defect exists in a film. Moreover, even if the hard film of patent document 2 coat | covers the TiN film | membrane on the CrN film | membrane, it is difficult to cover the defect once formed in the CrN film | membrane as it is.

  On the other hand, the application of Patent Document 3 or Patent Document 4 which is a technique for removing droplets is considered to be effective, but development of a new technique for imparting corrosion resistance for obtaining sufficient corrosion resistance is desired.

  In the above background, the present inventors are a method for producing a coated article excellent in corrosion resistance, in which a hard coating composed of at least two layers or more is coated on the surface of a substrate of the article by a physical vapor deposition method. Before the step of coating the second hard coating, comprising: coating the surface of the substrate with a first hard coating; and coating the surface of the first hard coating with a second hard coating. The method further comprises the step of polishing the surface of the first hard film to an arithmetic average roughness Ra of 0.05 μm or less and a maximum height Rz of 1.00 μm or less. This invention is proposed (Patent Document 5).

JP 2001-150500 A JP 2005-144992 A JP 2009-078351 A European Patent No. 0756019 International Publication WO2011 / 125657

In the method for manufacturing a coated article proposed by the present inventors in Patent Document 5, defects penetrating from the surface of the coating toward the substrate can be suppressed, and the corrosion resistance can be improved.
However, when a chromium-based nitride film with silicon or boron added to the second hard film is applied to improve wear resistance, the grain boundary becomes coarser as the film thickness increases in the single-layer film. In some cases, the corrosion progresses starting from the coarse grain boundaries on the surface.

  In view of the above problems, an object of the present invention is to provide a coated article having excellent corrosion resistance and a method for manufacturing the same even when silicon, boron, or the like is added in order to improve wear resistance.

  The inventors of the present invention have intensively studied a technique for simultaneously improving wear resistance and corrosion resistance of a hard film coated by physical vapor deposition, and have found a specific film structure that solves these problems.

That is, the present invention is a coated article in which a hard film is coated by a physical vapor deposition method on the surface of a base material of a metal-based article,
The hard film was coated with a layer which is a chromium-based nitride or carbonitride containing only 50% by atom of chromium with an atomic% of only a metal component (including a semimetal), and an upper layer than the a layer. A layer b in which nitrides or carbonitrides having different film thicknesses are alternately laminated, and each layer has a film thickness of 100 nm or less,
The surface of the a layer is polished, and each layer of the b layer contains 50 atomic% or more of chromium by atomic% of only a metal component (including a semimetal), and has corrosion resistance including silicon and / or boron in at least one of them. It is an excellent coated article.

Moreover, it is preferable that at least one of each layer of the said b layer contains 3-30% of silicon and / or boron in atomic% only of a metal component (a semimetal is included).
The b layer preferably has a hardness of 3000HV _0.025 or more.
The surface roughness of the b layer is preferably such that the arithmetic average roughness Ra is 0.05 μm or less and the maximum height Rz is 1.00 μm or less.
Moreover, it is preferable that the film thickness of the said a layer is 1.0-10.0 micrometers, and the film thickness of the said b layer is 1.0-10.0 micrometers.

The physical vapor deposition method is preferably an arc ion plating method.
The base material surface is preferably a base material surface of an injection molding part or a mold. The injection molding component is preferably a screw and / or a tip component of the screw.

Further, the present invention is a method for producing a coated article in which a hard film is coated on a substrate surface of an article having a metal base material by a physical vapor deposition method,
First, the substrate layer is coated with an a layer that is a chromium-based nitride or carbonitride containing 50 atomic% or more of chromium with only atomic percentage of metal components (including metalloid), and then the a layer. Polish the surface of the
Furthermore, it is a nitride or carbonitride having a different composition in which the thickness of each layer is alternately stacked at a thickness of 100 nm or less above the a layer whose surface is polished, each layer including a metal component (including a semimetal) And b) containing 50 atomic% or more of chromium with only atomic% and at least one of silicon and / or boron,
It is a manufacturing method of the coated article excellent in corrosion resistance which makes the hard layer contain the a layer and the b layer.
Moreover, it is preferable to change the negative bias voltage applied to the substrate during the coating period of the b layer.
Further, before the coating of the b layer, it is preferable that the surface of the a layer is polished so that the arithmetic average roughness Ra is 0.05 μm or less and the maximum height Rz is 1.00 μm or less.
Further, it is preferable that the negative bias voltage applied to the base material is made different between the initial stage and the final stage during the coating period of the b layer.
Moreover, it is preferable to change the negative bias voltage applied to the substrate by 10 V or more during the coating period of the b layer.

  The covering member adopting the present invention has very few defects penetrating from the surface of the coating toward the substrate, and is excellent in corrosion resistance. Therefore, the present invention is useful for injection molding parts, tools, molds and the like exposed to corrosive wear environments.

Sample No. which is an example of the present invention. 5 is a reflected electron image of a fractured surface structure of No. 5 by a scanning electron microscope. Sample No. which is an example of the present invention. 6 is an observation photograph of the b layer in FIG. It is a microscope picture of the hard film surface which shows the result of the corrosion test of the example of the present invention performed in Example 1. It is a microscope picture of the hard film surface which shows the result of the corrosion test of the example of the present invention performed in Example 1. It is a microscope picture of the hard film surface which shows the result of the corrosion test of the comparative example performed in Example 1. FIG. 2 is a micrograph of the surface of a hard coating film showing the results of a conventional corrosion test performed in Example 1. FIG. 2 is a micrograph of the surface of a hard coating film showing the result of a corrosion test performed in Example 2. It is the schematic of the film-forming apparatus used in the Example.

  In addition to removing droplets and particles of the a layer that is a hard coating and smooth polishing, the inventors have provided a wear resistance by providing a b layer of a hard coating having a specific laminated structure on the upper side. It has been found that the corrosion resistance and corrosion resistance are improved at the same time. Furthermore, a method for producing a coated article that is superior in corrosion resistance has been found and the present invention has been achieved.

First, the b layer which is the most important feature of the present invention will be described.
The b layer of the present invention is a laminated film in which nitrides or carbonitrides having different compositions are alternately laminated, with the layer being 100 nm or less in thickness above the a layer whose surface is polished.
When the b layer is not a laminated film but a single layer film, the crystal grain boundary of the chromium nitride or carbonitride tends to be coarsened as the film thickness increases, and defects such as voids are likely to occur.
On the other hand, by alternately laminating nitrides or carbonitrides having different compositions so that the crystal grain boundaries do not become coarse, the corrosion resistance is remarkably improved as compared with the case of a single layer film. In order to exert these effects, the thickness of each layer stacked alternately is set to 100 nm or less. More preferably, it is 50 nm or less.
In addition, when the b layer is formed as a laminated film with a thickness of each layer being 100 nm or less, the adhesion strength tends to be improved as compared with the single layer film.
Each layer constituting the b layer is preferably a nitride that is superior in corrosion resistance.

  Each layer of the b layer can exhibit excellent corrosion resistance by containing 50 atomic% or more of chromium, which is an element type having excellent corrosion resistance, in atomic% of only the metal component (including metalloid). More preferably, the chromium content in each layer is 70 atomic% or more. In the present invention, “semimetal” refers to silicon and boron.

Since at least one of the layers of the b layer contains silicon and / or boron, the entire b layer has high hardness, and the structure is refined, so that the corrosion resistance and the wear resistance are further improved. . Therefore, even when a reinforcing material such as glass fiber is added to plastic, for example, it exerts a remarkable effect in preventing corrosion wear of the coated article due to wear.
In order to achieve both wear resistance and corrosion resistance at a higher level, at least one of the laminated films has an addition amount of silicon and / or boron of 3 to 30% in atomic% of only the metal composition (including metalloid). Preferably there is. More preferably, it is 5% or more and / or 25% or less. Further, it is preferably 8% or more and / or 20% or less.
Moreover, you may coat | cover the film | membrane which consists of nitride, carbonitride, a carbide | carbonized_material, etc. on b layer.

In the present invention, the a layer, which is a chromium-based nitride or carbonitride containing 50 atomic% or more of chromium with only atomic percentage of the metal component (including metalloid), is polished to remove droplets and particles. . By polishing the surface of the a layer, the hard film provided immediately above it is coated so as to fill in the fine irregularities on the surface of the a layer, and the penetration defects up to the substrate are blocked, thereby improving the corrosion resistance. it can. And, by providing a b layer made of a specific laminated film having excellent corrosion resistance on the upper layer than the a layer whose surface is polished, the progress of corrosion from the surface side of the film is remarkably suppressed, and excellent corrosion resistance can be exhibited. it can.
The b layer is preferably provided immediately above the a layer, so that the film structure becomes simple and the manufacturing cost and man-hours can be reduced.

In addition to the b layer, the a layer to be coated on the substrate side is made of chromium nitride or carbonitride containing 50 atomic% or more of chromium by atomic% of only the metal component (including semi-metal), Corrosion resistance can be demonstrated. More preferably, the chromium content is 70% or more. Further, the a layer is preferably a nitride that is superior in corrosion resistance.
As long as the average composition of the a layer contains 50 atomic% or more of chromium by atomic% of only the metal component (including metalloid), a laminated structure may be used.
Between the base material and the a layer, for example, a film made of metal, nitride, carbonitride, etc. for ensuring adhesion may be provided, but by providing an a layer directly on the base material, The film structure is simple, and manufacturing costs and man-hours can be reduced, which is preferable.

  The fact that the surface of the a layer is polished can be confirmed by observing a cross section of the mirror-finished film. That is, a smooth polished surface can be confirmed at the interface between the a layer and the b layer. Then, by polishing the surface of the a layer, the interface between the a layer and the b layer of the present invention can have less than 2 droplets having a major axis of 1 μm or more per 50 μm. Even if the major axis is a droplet having a major axis of less than 1 μm and the major axis is 1 μm or more, the presence of about two per 50 μm is preferable because it does not significantly affect the corrosion resistance.

Further, the hardness of the b layer is controlled by controlling the composition of the laminated film, the negative bias voltage applied to the substrate during the film formation period, and the like to be 3000 HV _0.025 or more, thereby adding a hard addition such as glass fiber. It is preferable that the wear progresses severely during the molding of the resin material including the material.

  The film thickness of the a layer is preferably 1.0 to 10.0 μm, and the film thickness of the b layer is preferably 1.0 to 10.0 μm. By using these film thicknesses, the corrosion resistance can be sufficiently exhibited. If it is thinner than this, it is difficult to obtain an excellent corrosion resistance effect. If it is thicker than this, the adhesive strength of the whole film may be lowered. Moreover, it is preferable that the film thickness of a layer and b layer is 3.0-6.0 micrometers.

  The present invention is an injection-molded part used for the formation of plastics and rubbers that require particularly corrosion resistance among coated articles (for example, screws, screw heads, check rings, seal rings, cylinders, backflow prevention rings, spacers, etc.) And / or is preferably applied to a mold because the corrosion resistance is remarkably improved and the life is extended.

The hard coating of the present invention can be coated at a temperature lower than the tempering temperature of a base material made of a metal such as cold die steel, hot die steel, and high speed steel by being coated by physical vapor deposition. Variations in the dimensions of the material can be suppressed. In addition, compressive residual stress can be applied to the hard coating, and the mechanical properties of the hard coating can be improved.
The substrate may be preliminarily applied with a surface hardening process using diffusion such as nitriding or carburizing.

  The metal material of the base material is not particularly defined, and for example, as described above, cold die steel, hot die steel, high speed steel, and cemented carbide can be used. In this regard, these improved metal types can be applied, including standard grades (steel types) according to JIS.

  The hard film of the present invention is preferably coated by the arc ion plating method among physical vapor deposition methods, since the film adhesion and the film density are particularly high. Each of the a layer and the b layer is preferably coated by an arc ion plating method having excellent adhesion.

The surface of the layer a coated with the production method of the present invention can not only remove droplets and particles, but also improve the corrosion resistance by smooth polishing the surface of the film. Then, the arithmetic average roughness Ra of the surface roughness as defined in JIS-B-060 1 -2001 is a 0.05μm or less, and the maximum height Rz is polished so as to be below 1.00μm is less uneven Since the surface state is extremely smooth, the corrosion resistance is improved, which is preferable. In order to surely remove droplets, particles and the like and to obtain a smooth surface state, the following polishing method is preferable.
(1) A method of polishing the surface of a hard film with an abrasive cloth holding a polishing agent such as diamond paste (2) Using a polishing agent having diamond particles and humidity, and sliding at a high speed on a film coated on a substrate. Polishing by the generated friction force, so-called aero lapping (Aero lapping is a registered trademark of Yamashita Towers Co., Ltd.) etc. (3) Injecting an abrasive with elasticity and adhesion without using air Polishing method by so-called smap (SMAP) ("Smap" is a specular shot machine of Kamei Ironworks, Inc.) etc. Further, it is more preferable to polish diamond paste of 3 μm or less after these treatments Smoothing can be realized.
The surface roughness of the layer b is preferably such that the arithmetic average roughness Ra is 0.05 μm or less and the maximum height Rz is 1.00 μm or less.

During the coating period of the b layer, it is preferable to change the negative bias voltage applied to the substrate.
When the negative bias voltage applied to the substrate during the coating period is low, the particle layer tends to be relatively fine, and when the negative bias voltage is high, the particle layer tends to be relatively coarse. Further, by changing the bias voltage, not only the shape such as the grain size but also the crystal orientation changes.
Therefore, by changing the negative bias voltage applied to the substrate during the coating period, there are not a few voids caused by droplets and particles that continue from the inside of the coating to the surface even if polishing is performed on the way. It is considered that pores and pinhole-like gap defects are blocked in the middle, and the progress of corrosion does not reach the inside of the base material, resulting in a coated article having excellent corrosion resistance.
Therefore, by changing the negative bias voltage applied to the substrate during the coating period of the b layer that suppresses the coarsening of the crystal grain boundaries and suppresses the generation of voids and the like as the laminated film, Corrosion resistance can be remarkably improved.

During the coating period of the b layer, it is preferable that the bias voltage at the initial stage and the end stage are made different so that the corrosion path is easily cut off during the coating.
If the change in the bias voltage is small, the effect of improving the corrosion resistance may not be sufficiently obtained. Therefore, in order to further improve the corrosion resistance, it is preferable to change the negative bias voltage applied to the base material by 10 V or more during the coating period of the b layer. More preferably, it is 30 V or more. Furthermore, it is 50V or more.
More preferably, the negative bias voltage applied to the substrate is changed by 10 V or more in the initial and final stages during the coating period of the layer b. More preferably, it is 30 V or more. Furthermore, it is 50V or more.
The a layer and the b layer preferably cover a negative bias voltage applied to the substrate in the range of −50 to −200V.

  An arc ion plating apparatus was used as the means for coating the hard film. A schematic diagram of the film forming apparatus is shown in FIG. The film forming chamber 2 includes a plurality of arc discharge evaporation sources 3, 4, and 5 for mounting various targets (cathodes) 1, and a substrate holder 6 for mounting the substrate 7. A rotation mechanism 8 is provided below the substrate holder 6, and the substrate 7 rotates and revolves through the substrate holder 6. And when the base material 7 opposes various targets, the film | membrane by this target is coat | covered. Note that the target used in this example is a metal target produced by a powder metallurgy method.

The evaporation sources 3 to 5 were equipped with a target constituting the metal or alloy component of the hard coating and a target for metal ion etching. JIS-SKD11 modified steel tempered to 57-60 HRC is used as the base material, and before the base material is coated with a hard coating, the surface of the base material has an arithmetic average roughness Ra of 0.01 μm and Rz of 0. Polished to 07 μm. The substrate whose surface was polished was degreased and washed and fixed to the substrate holder 7. And the base material was heated to 450 degreeC vicinity with the heater for heating (not shown) installed in the chamber 2, and it hold | maintained for 50 minutes. Next, Ar gas was introduced, a bias voltage of −200 V to 500 V was applied to the substrate, and a 20 minute plasma cleaning process (Ar ion etching) was performed.
Subsequently, a bias voltage of −800 V was applied to the substrate, and metal ion etching was performed for about 5 minutes using a metal Ti target (including cooling after metal ion etching). Details of the coating conditions for each sample will be described below.

<Sample No. 1-7, 11>
After ion etching of the substrate, nitrogen gas is introduced, a bias voltage of −130 V is applied to the substrate, and the substrate temperature is 450 ° C. and the reaction gas pressure is 3.0 Pa. The a layer made of CrN was coated so as to have a thickness of 0 μm.
Then, in order to grind | polish the surface of CrN smoothly, the base material was taken out from the chamber and surface treatment was performed using the Yamato towers company aero lapping apparatus (AERO LAP YT-300). Further polishing is then performed with a 1 μm diamond paste, followed by a mirror surface shot machine SMAP-II manufactured by Kamei Iron Works, with an arithmetic average roughness Ra of 0.05 μm or less and a maximum height Rz. Was polished to be 1.00 μm or less.

And after degreasing washing, it returned in the chamber again. First, Ar ion etching and metal Ti etching were performed, and nitrogen gas was introduced.
Subsequently, 150 A of current was applied to the two types of targets, a bias voltage of -130 V was applied to the base material, and the base material temperature was 450 ° C. and the reaction gas pressure was 3.0 Pa. did. Then, over 5 minutes, the bias voltage was changed from -130 V to -90 V, and finally, coating was performed at -90 V for 15 minutes to coat a laminated film of chromium-based nitride of about 3.0 to 4.0 μm. . The rotation speed of the substrate during the coating period was 6 rpm.

<Sample No. 8-10, 12-17>
Sample No. which is an example of the present invention. 8 to 10, Sample No. as a comparative example. Nos. 12 to 17 are sample Nos. That are the examples of the present invention before the coating of the a layer. 1 to 7 and the same as Sample No. 11 as a comparative example. Thereafter, the substrate was coated with a monolayer film of about 3.0 to 5.0 μm under the conditions of a substrate temperature of 450 ° C. and a reaction gas pressure of 3.0 Pa with a constant bias voltage of −130 V.

<Sample No. 18-20>
Sample No. which is a conventional example. In 18-20, the bias voltage was kept constant at -120 V, and the monolayer film was coated at about 6.0-7.0 μm.

<Sample No. 21>
Sample No. which is a conventional example. In No. 21, the bias voltage was kept constant at -120 V, and polishing was not performed halfway, and two types of hard coatings were successively coated in the same furnace at about 3.0 to 4.0 μm.

  For all samples, the surface of each sample was aero-wrapped, diamond paste polished, surface treatment using a mirror shot machine SMAP-II manufactured by Kamei Iron Works, and arithmetic average roughness Ra was Polishing was performed so that the maximum height Rz was 0.05 μm or less and the maximum height Rz was 1.00 μm or less.

  These samples were subjected to surface roughness measurement, hardness, scratch test, structure observation, and corrosion resistance evaluation of the hard coating. Each evaluation test method is shown below.

(Surface roughness measurement)
According JIS-B-060 1 -2001, it was measured arithmetic mean roughness Ra and maximum height Rz than the roughness curve. The measurement conditions are an evaluation length: 4.0 mm, a measurement speed: 0.3 mm / s, and a cut-off value: 0.8 mm. Table 1 shows the measurement results of the surface roughness of the hard coating.

(Film hardness measurement)
As for the Vickers hardness of the film, the hardness HV _0.025 of the film surface was measured by a micro Vickers tester according to JIS-Z-2244. The test load is 0.2452N. The hardness measurement results of the hard coating are shown in Table 1.

(Scratch test)
In order to evaluate the adhesion of the film, the peeling load of the film was measured using a scratch tester (REVETEST) manufactured by CSM.
The measurement conditions were: measurement load: 0.9 to 120 N, load speed: 99.25 N / min, scratch speed: 10 mm / min, scratch distance: 12 mm, AE sensitivity: 5, indenter: Rockwell, diamond, tip radius: 200 μm Hardware setting: Fn contact 0.9 N, Fn speed: 5 N / s, Fn removal speed: 10 N / s, approach speed: 2% / s.
As for the peeling load of the film, the initial chipping generation load was A load, and the load when the hard film was completely peeled from the base material was B load. The measurement results are shown in Table 2.

(Corrosion resistance evaluation test)
A test was conducted in which a sample was immersed in a 10% aqueous sulfuric acid solution for 10 hours, simulating a corrosive gas such as a halogen gas generated during actual injection molding.
The temperature of the aqueous solution was 50 ° C., and masking was performed except for the coated surface of the test piece according to JIS-G-0591-2007. After immersion, the weight loss due to the corrosion was recorded, and pitting corrosion (pits) appearing on the surface was observed. The area ratio of corrosion on the test surface was evaluated by a micrograph (magnification: 8 times).
The number of pitting corrosion is determined by classifying the pitting corrosion (pits) appearing in the micrograph as a class A with a diameter of 0.8 mm or more and a class B with a size less than 0.2 to 0.8 mm. The number of meals was measured.
Moreover, the corrosion resistance was determined as follows.
◎: No pitting corrosion was observed. ○: Pitting corrosion with an area ratio of 1% or less was observed. Δ: Pitting corrosion with an area ratio exceeding 1 to 10% was observed. X: Area ratio exceeding 10%. Table 2 shows the test results.

  The surface of the film after the corrosion resistance evaluation test is shown in FIGS. 3 to 6 (in the figure, the light-colored portion confirmed to be spherical is pitting corrosion).

Sample No. of the present invention example. In Nos. 1 to 7, pitting corrosion was not confirmed and excellent corrosion resistance was shown. Moreover, it was excellent also in film hardness and adhesiveness.
In FIG. 5 shows a cross-sectional observation photograph. A smooth polished surface was observed between the a layer and the b layer, and no penetration defect from the coating surface was confirmed. Moreover, the b layer laminated | stacked alternately was different from the a layer of a single layer membrane | film | coat, and the clear crystal grain boundary was not confirmed.
In FIG. The observation photograph by the transmission electron microscope of b layer in 5 is shown. The relatively bright layer is CrSiBN and the relatively dark layer is CrN. It was confirmed that the thickness of each layer was alternately stacked with a thickness of 100 nm or less. All of the samples of the present invention have the sample No. 5 was the same tissue form.

Sample No. which is an example of the present invention. 2, 4, 5, and 8-10 were simulated by immersing the sample in a 10% sulfuric acid aqueous solution for 40 hours while simulating a corrosive gas such as a halogen gas. The evaluation method is the same as in Example 1. The test results are shown in Table 3 and FIG.
It was confirmed that by changing the negative bias voltage applied to the substrate during the coating period of the layer b, no pitting corrosion was confirmed even in a long-time corrosion evaluation test, and excellent corrosion resistance was exhibited.

  The present invention can be applied to MIM (metal injection molding) molds and various machine parts in addition to molds and tools for molding plastics and rubber, and injection molding parts.

1, target 2, film formation chamber 3, evaporation source 4, evaporation source 5, evaporation source 6, base material holder 7, base material 8, rotation mechanism

Claims (13)

Metal A coated article hard substance coating on the substrate surface of the article to the base material is coated,
The hard film was coated with a layer which is a chromium-based nitride or carbonitride containing only 50% by atom of chromium with an atomic% of only a metal component (including a semimetal), and an upper layer than the a layer. A layer b in which nitrides or carbonitrides each having a thickness of 100 nm or less and a different composition are alternately laminated,
The are two fewer than der per 50μm at the interface in the major axis 1μm or more droplets sectional observation at the interface between a layer and the b layer, each layer of the b layer is a metal component (including semimetal) only A coated article excellent in corrosion resistance, characterized by containing 50 atomic% or more of chromium by atomic% and at least one of silicon and / or boron. 2. The coating with excellent corrosion resistance according to claim 1, wherein at least one of the layers of the b layer contains 3 to 30% of silicon and / or boron in an atomic% of only a metal component (including a semimetal). Goods. The coated article having excellent corrosion resistance according to claim 1 or 2, wherein the hardness of the b layer is 3000HV _0.025 or more. The surface roughness of the b layer is excellent in corrosion resistance according to any one of claims 1 to 3, wherein the arithmetic average roughness Ra is 0.05 µm or less and the maximum height Rz is 1.00 µm or less. Coated articles. 5. The film thickness of the a layer is 1.0 to 10.0 μm, and the film thickness of the b layer is 1.0 to 10.0 μm. A coated article having excellent corrosion resistance as described in 1. The coated article with excellent corrosion resistance according to any one of claims 1 to 5 , wherein the base material surface is a base material surface of an injection molding part or a mold. The coated article having excellent corrosion resistance according to claim 6 , wherein the injection molding component is a screw and / or a tip component of the screw. A method of manufacturing a coated article in which a hard film is coated by a physical vapor deposition method on the surface of a base material of a metal-based article,
First, the substrate layer is coated with an a layer that is a chromium-based nitride or carbonitride containing 50 atomic% or more of chromium with only atomic percentage of metal components (including metalloid), and then the a layer. Polish the surface of the
Furthermore, it is a nitride or carbonitride having a different composition in which the thickness of each layer is alternately stacked at a thickness of 100 nm or less above the a layer whose surface is polished, each layer including a metal component (including a semimetal) And b) containing 50 atomic% or more of chromium with only atomic% and at least one of silicon and / or boron,
A method for producing a coated article having excellent corrosion resistance, wherein the hard film includes the a layer and the b layer. The method for producing a coated article having excellent corrosion resistance according to claim 8 , wherein a negative bias voltage applied to the substrate is changed during the coating period of the b layer. Prior to coating of the b layer, according to claim 8 wherein the arithmetic average roughness Ra of the surface of a layer is 0.05μm or less and the maximum height Rz is characterized by polishing so that less 1.00μm or 10. A method for producing a coated article according to 9 . During the coating period of the b layer, the production of superior coated article in corrosion resistance according to any one of claims 8 to 1 0, characterized by varying the bias voltage of the negative pressure applied to the substrate in the initial and late Method. The method for producing a coated article having excellent corrosion resistance according to any one of claims 8 to 11, wherein a negative bias voltage applied to the substrate is changed by 10 V or more during the coating period of the b layer. . The method of manufacturing a coated article having excellent corrosion resistance according to any one of claims 8 to 12, wherein the physical vapor deposition method is an arc ion plating method.