JP2011127205A - Coated die having excellent lubricant adhesiveness and durability, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated die which has excellent lubricant adhesiveness and durability even in the environments of forging, die casting or the like which have been made severe, and to provide a method for producing the coated die. <P>SOLUTION: The coated die is obtained by coating the surface of a die base material with a film by a sputtering process. The film is made of a hard film composed of one or more selected from nitrides, carbides and carbonitrides, and a lubricating film covered directly thereon, and made of one or more selected from nitrides, carbides and carbonitrides. The lubricating film has surface roughness of the arithmetic average roughness Ra: ≥0.08 μm, the maximum height Rz: ≥0.84 μm, and is composed of an acicular grains having grain boundaries in an almost vertical direction to the surface of the die base material. The above film can be achieved by controlling film deposition conditions upon its sputtering. For example, in the lubricating film, base material vias voltage upon coating is controlled to -0 to -60V. In the hard film, base material bias voltage is preferably controlled to >-60V and ≤-160V. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coated mold that is used for die casting, hot forging and the like and requires seizure resistance, and a method for producing the same.

  Conventionally, in a mold used for die casting or hot forging, a coated mold having various surface treatments on its work surface has been proposed. And as the coating means, it can be processed at a low temperature (below the A1 transformation point) with little deformation and deformation of the mold base material, and the coating film is excellent in crack resistance by applying a residual compressive stress. Application of physical vapor deposition (hereinafter referred to as PVD method), which can be used as a film, is increasing.

  On the other hand, with the recent weight reduction, high performance, and diversification of applications of die-cast and forged products, the accuracy of the mold for the product dimensions and the thermal stress conditions applied to the mold surface are increasing year by year. It is becoming strict and the mold life tends to become unstable. In particular, since the die casting mold has a surface in contact with an active molten metal, the occurrence of fatigue cracks due to melting, seizure, or thermal stress is significant.

  As a countermeasure, a release agent has been sprayed on the mold surface for each molding. In other words, this mold release agent not only improves the mold releasability between the mold and the product to be processed, but also acts as a cooling and lubricant for the mold surface. It greatly affects the provision of However, in the case of a coated mold, the adhesion of the lubricant is not sufficient in the conventional film, so that the effect of the film itself is not sufficiently exhibited in addition to the effect of the lubricant.

  Therefore, on the hard film such as nitride, a metal film having a surface roughness Rz: 4 to 15 μm or more than 15 μm to 40 μm is coated by an arc ion plating method. Coated tools for hot working with improved adhesion of the lubricant have been proposed (Patent Documents 1 to 3). In addition, a hard film made of nitride is coated with a nitride having “projection-like particles” of less than 5 to 200 nm, which also increases the wear resistance of the film itself and the retention capability of the lubricant. A member has been proposed (Patent Document 4). The film of Patent Document 4 is coated by a sputtering method. By setting the substrate bias voltage at the time of sputtering to −100 V, the surface roughness is about 0.5 μm or less for Ry (corresponding to the maximum height Rz according to JIS-B-0601 (2001)), and Ra is about 0.00. While maintaining a smoothness of not more than 05 μm, it is possible to provide protrusion-like particles different from the generally referred macroparticle.

JP 2002-292442 A JP 2002-307129 A JP 2005-246468 A JP 2007-084899 A

  The above-described method is effective for improving the performance of the mold. However, there is room for improvement in the impregnation of the lubricant on the mold surface. In other words, regarding the roughening technique of the coating surface, for example, if a metal film as in Patent Documents 1 to 3 is used, the seizure resistance is improved in a severe use environment due to its soft characteristics. It is conceivable that the function cannot be fully exhibited. And in patent document 4 which comprised the film | membrane with the nitride, even if it has provided the protruding particle | grains on the surface, a smoothness is still high and the subject remains in adhering an appropriate amount of lubricants.

  In addition, the recent trend toward near-net shape of products to be processed increases the stress applied to the work surface of the mold when it is formed into a complex product shape. In addition, there may be a site where an appropriate amount of lubricant adheres and a portion where the lubricant does not adhere to the complex-shaped mold work surface. Is likely to occur.

  In addition, in order to improve workability at the site of die casting and forging, and to reduce work costs, “release agent-free” that does not use a release agent as much as possible is also desired. Therefore, even when a mold release agent (lubricant) is used, it is important to reduce the amount used as much as possible and improve the durability of the mold.

  An object of the present invention is to provide a coating mold excellent in lubricant adhesion and durability, which solves the above problems, and a method for producing the same.

  First, the present inventor conducted a detailed examination of the physical structure of the film as a means for improving the adhesion of the lubricant to impart excellent seizure resistance and galling resistance. As a result, it has been found that not only the surface roughness of the film is related to the improvement of the adhesion, but also an internal structure that easily adheres when the lubricant is impregnated. In addition, even if the inventor has a film structure that prioritizes the adhesion of the lubricant, the entire film has a composite structure in which another film is combined with the lower layer to maintain mechanical characteristics. I found it. Then, the present invention has been reached by studying film forming conditions that can achieve these film structures.

  That is, the present invention is a coated mold in which a film is coated on the surface of a mold base by a sputtering method, and the film includes a hard film made of at least one of nitride, carbide, and carbonitride, The lubricating film is composed of one or more of nitride, carbide, and carbonitride coated directly thereon, and the lubricating film has a surface roughness of arithmetic average roughness Ra: 0.08 μm or more and a maximum height. Rz: 0.84 μm or more, and is an aggregate of acicular particles having an interface in a direction substantially perpendicular to the surface of the mold base, and is excellent in lubricant adhesion and durability It is a mold. It is preferable that the hard film and the lubricating film have substantially the same composition, and / or, on the surface of the lubricating film, it is preferable that the protrusions of the needle-like particles have a polygonal shape.

  Further, the lubricating film preferably has a cubic crystal structure and preferably has a maximum intensity at (111) in X-ray diffraction, and / or the hard film has a cubic crystal structure and is in X-ray diffraction. Preferably it has a maximum strength at (200). The hard film and / or the lubricating film is made of a nitride, carbide, or carbonitride of one or more elements selected from Ti, Cr, Al, Si, W, Nb, Mo, V, B, and Hf. It is desirable to consist of at least one of them.

  And this invention is a manufacturing method of the coating metal mold | die which coat | covered the film | membrane by sputtering method on the surface of a mold base material, Comprising: This film | membrane is hard which consists of 1 or more types of nitride, carbide, and carbonitride And a lubricating film made of at least one of nitride, carbide, and carbonitride coated on the film, and the lubricating film has a base material bias voltage of −0 V to −60 V at the time of coating. It is a method for producing a coated mold excellent in lubricant adhesion and durability, characterized by coating by a sputtering method. Further, the hard film is preferably coated by a sputtering method in which the substrate bias voltage at the time of coating is over -60V to -160V. The hard film and the lubricating film preferably have substantially the same composition.

  According to the mold of the present invention, the film coated on the work surface has both excellent wear resistance and lubricant adhesion. Therefore, by using this coating die, high productivity can be maintained even in recent severe die casting and forging environments. Moreover, it can respond also to reducing the usage-amount of a mold release agent, and becomes an indispensable technique for the improvement of mold performance.

It is a scanning electron micrograph of the film | membrane surface of this invention example 3, and a torn surface. It is a scanning electron micrograph of the film | membrane surface of this invention example 4, and a torn surface. 6 is a scanning electron micrograph of the coating surface and fracture surface of Comparative Example 5. It is a scanning electron micrograph of the film surface and fracture surface of Comparative Example 6. 6 is a scanning electron micrograph of the coating surface and fracture surface of Comparative Example 7. 10 is a scanning electron micrograph of the coating surface and fracture surface of Comparative Example 8. It is a figure which shows the evaluation criteria used with the aluminum melt adhesion test of the Example.

  The feature of the coated mold of the present invention is the structure of the coating coated on the work surface. That is, a lubricating film having a special structure that exhibits excellent lubricant adhesion is preferably laminated and coated with substantially the same composition on a hard film having excellent wear resistance. Hereinafter, each component requirement will be described.

(1) A coated mold in which a surface of a mold base is coated with a film by a sputtering method.
The film coated on the mold of the present invention is composed of a multilayer structure of a hard film and a lubricating film thereon. The lubricating film has the surface and internal structure described below, which is an aggregate of “needle-like particles” that adjusts the surface roughness and gives it an effect to impart excellent adhesion to the lubricant. There is a need. In order to achieve these two structures, the sputtering method is the most suitable among the PVD methods. As a method for adjusting the surface roughness, the use of droplets by the arc ion plating method is also known. However, because the droplets are attached particles that do not constitute the substance of the film, they may easily fall off when the usage conditions become severe. There is.

  As the lubricating film is coated by the above sputtering method, if the hard film to be coated thereunder is also coated by the sputtering method, the coating of the present invention can be completed continuously in one batch. Therefore, efficiency is good. Therefore, in the present invention, a sputtering method is used for the covering means (a preferable manufacturing method will be described later).

(2) The film is a hard film made of at least one of nitride, carbide, and carbonitride, and a lubricating film made of at least one of nitride, carbide, and carbonitride coated directly thereon. Consists of.
For the types of nitrides, carbides, and carbonitrides that constitute the hard film, no special provision is required for the specific requirements such as the composition of the components. That is, a known hard film that has been conventionally used or proposed as a film having excellent durability such as hardness and wear resistance can also be applied. For example, a nitride, carbide, or carbonitride of one or more elements selected from Ti, Cr, Al, Si, W, Nb, Mo, V, B, and Hf is preferable. In the case of the present invention, specifically, nitrides of Ti and Al, nitrides of Cr and Al, and nitrides of Cr, Al, and Si have a good balance of hardness and oxidation resistance, and particularly excellent durability. And is excellent in mass productivity.

  As for the lubricating film, there is no need for the type of the lubricating film, and a known film made of at least one of nitride, carbide and carbonitride can be applied. For example, a nitride, carbide, or carbonitride of one or more elements selected from Ti, Cr, Al, Si, W, Nb, Mo, V, B, and Hf is preferable. Since the lubricating film is also a nitride, carbide or carbonitride, the mechanical properties can be maintained even if the physical structure is controlled to give priority to the adhesion of the lubricant described below. The component composition is preferably substantially the same as that of the hard film. As a result, the lubricating film also becomes a nitride, carbide, carbonitride having substantially the same compound composition as the hard film, so that the adhesion strength of the lubricating film to the hard film can be maintained higher, so when using the mold The peeling of the lubricating film due to thermal expansion can be suppressed.

(3) The lubricating film has an arithmetic average roughness Ra of 0.08 μm or more and a maximum height Rz of 0.84 μm or more, and has an interface in a direction substantially perpendicular to the surface of the mold base. It is an aggregate of acicular particles.
In order to improve the adhesion of the lubricant, it is first necessary to adjust the form of the coating surface itself in contact with the workpiece. In other words, if the surface of the lubricant film is smooth, even if the total amount of lubricant interposed between the workpiece and the workpiece is sufficient, it is not uniformly maintained over the entire surface, and the lubricant is partially retained. A shortage occurs. As a result, in addition to local seizure and galling, it also causes generation of melting damage and cracks due to uneven cooling of the mold surface. Moreover, the mold release property of the molded body after processing also deteriorates. Therefore, the surface roughness of the lubricating film of the present invention is arithmetic average roughness Ra: 0.08 μm or more and maximum height Rz: 0.84 μm or more. Preferably, Ra: 0.09 μm or more and / or Rz: 0.9 μm or more. If the roughness value is too large, the wear resistance is lowered due to the coarsening of the particles. Therefore, Ra is preferably 0.30 μm or less and / or Rz: 3.0 μm or less. The measuring procedure for the surface roughness may follow JIS-B-0601 (2001).

  The lubricating film of the present invention is an aggregate of “needle particles” whose internal structure has an interface in a direction substantially perpendicular to the surface of the mold base (for example, the fracture surface of FIG. 1). In other words, by adjusting the surface roughness as described above, an appropriate amount of lubricant can be held uniformly on the surface of the lubricating film, and the internal structure of the lubricant film is also excellent in the impregnation of the lubricant. The adhesion is improved. Therefore, the lubricating film which is an aggregate of the acicular particles according to the present invention is excellent in lubrication because the lubricant is easily impregnated in the interface between the individual acicular particles and the lubricant is retained throughout the film. Expresses agent adhesion.

  The above-mentioned acicular particles appear on the surface of the film, and the tips thereof contribute to the achievement of the sharp surface roughness value of the present invention. And it is preferable that this acicular particle is polygonal in the surface of the lubricating film where the tip appears (for example, the surface of FIG. 1). That is, since the sharp tip that forms the surface roughness shape has a “corner”, the adhesion of the lubricant can be further improved.

  The above-mentioned lubricating film composed of an aggregate of acicular particles satisfying the surface roughness value of the present invention, and further, the above-mentioned lubricating film whose surface has sharp undulations have the film forming conditions of the sputtering method. This can be achieved by controlling. A particularly important control factor among the film forming conditions is the bias voltage applied to the mold base during sputtering. Although details will be described later, if the film forming conditions are not appropriate, individual factors constituting the surface roughness are flat dome-like “projection-like particles” as described in Patent Document 4, and the internal structure of the lubricant is It becomes difficult to impregnate (for example, FIG. 3 and FIG. 4), and it becomes difficult to obtain the lubricant adhesion of the present invention.

  Further, even with the arc ion plating method as described in Patent Documents 1 to 3, the coating surface roughness can be adjusted by the droplets. However, the mechanism for imparting roughness is based on “adhering particles” different from the present invention (FIG. 6), and the droplets are likely to fall off in a severe use environment. And since the impregnation property of the lubricant is poor, it is still difficult to achieve the lubricant adhesion of the present invention.

(4) It is preferable that the lubricating film has a cubic crystal structure and has a maximum strength at (111) in X-ray diffraction. And / or the hard film preferably has a cubic crystal structure and has a maximum strength at (200) in X-ray diffraction.
By satisfying the above requirements, the lubricating film has high crystallinity and a large crystal grain size, and the surface tends to have the polygonal shape described above. Therefore, it is preferable for further improving the adhesion of the lubricant of the present invention. On the other hand, the hard film satisfies the above requirements, and thus has a high hardness and is preferable for improving the durability of the coating mold. These preferable requirements for both films can be adopted depending on the application of the coating mold of the present invention. Note that the lubricating film and / or the hard film may have a hexagonal crystal structure.

  The crystal plane can be adjusted by controlling the substrate bias voltage according to the manufacturing method of the present invention described later. That is, by reducing the negative bias voltage applied to the substrate, the crystal plane is oriented to (111). Preferably, this tendency increases if the independent anode employed in the embodiment is provided and the negative voltage is reduced. On the other hand, by increasing the above substrate bias voltage and preferably the independent anode voltage to the negative side, the crystal plane is oriented to (200).

  In addition, it is preferable that the average crystal grain size of the lubricating film is larger than the average crystal grain size of the hard film. This is because the average grain size of the hard film with excellent wear resistance is increased by increasing the size of the lubricating film formed on the hard film, thereby maintaining the durability of the film while maintaining the durability of the film. Can be increased. Specifically, it is preferable that the lubricating film has an average crystal grain size of less than 30 nm and that of the lubricating film has a thickness of 30 to 1000 nm. Note that the adhesion strength between the two films, which is reduced to some extent due to the difference in crystal grain size, is that both films are made of the same kind of compound (one or more of nitride, carbide, carbonitride), and It can be sufficiently compensated by making it substantially the same component. And about the boundary of both films | membranes by the said particle size difference, adhesive strength can be further compensated by changing the particle size of the site | part continuously.

  The film structure of the present invention composed of the hard film and the lubricating film described above can be achieved by controlling the film forming conditions of the sputtering method. That is, the lubricating film can be achieved by a sputtering method in which the substrate bias voltage at the time of coating is −0 V to −60 V. By lowering the negative bias voltage applied to the base material (that is, approaching −0 V), the internal structure of the lubricating film shifts from a dense structure to the above-described aggregate of acicular particles, which is a feature of the present invention. As a result, the surface of the lubricating film also shifts from a smooth structure without gaps to a rough structure with sharp tips, which is a feature of the present invention. Therefore, in order to achieve the lubricating film having the structure of the present invention, the negative bias voltage applied to the substrate is set to 60 V or less. The negative pressure is preferably 40 V or less. Note that if the surface roughness of the lubricating film becomes too large, the wear resistance is reduced due to the coarsening of the particles, so the preferred negative bias voltage is set to 20 V or more.

  The hard film to be coated prior to the lubricating film preferably has a base material bias voltage of more than −60V to −160V. That is, according to the above, in order to obtain a dense hard film having excellent durability, it is effective to control the negative substrate bias voltage to be high, and it is possible to make the lubricating film higher than that at the time of coating. preferable. Therefore, the substrate bias voltage when coating the hard film is a negative pressure exceeding 60V. Desirably, it is 80V or more, more desirably 100V or more. On the other hand, when the bias voltage becomes too high, the coated film is re-sputtered, and the film thickness of the edge shape portion becomes thin. Moreover, a compositional difference arises when a light element is ejected, and it does not become the target composition. Therefore, a preferable negative bias voltage is set to 160 V or less. More preferably, it is 140 V or less.

  In the mold base before coating, adjusting the surface roughness to Ra: 0.03 μm or more and Rz: 0.3 μm or more ensures the surface roughness of the coating of the present invention. preferable. More preferably, Ra: 0.05 μm or more, Rz: 0.5 μm or more. In the die base material used for die-casting or hot forging, the work surface is usually not mirror-finished, so that the above surface roughness region can be satisfied.

<Preparation of sample for evaluation>
Before coating various types of coatings on actual molds, samples for evaluating the form of the coatings were prepared. For the base material, high-speed steel SKD61 specified by JIS is prepared, and this is tempered to 43HRC by tempering at 540-580 ° C after quenching by heating with nitrogen gas cooling from heating at 1180 ° C in vacuum. It was. The substrate has a cylindrical shape with a thickness of 5 mm and a diameter of 20 mm. The surface of the cylindrical substrate was adjusted to have a surface roughness Ra: 0.05 μm and Rz: 0.5 μm. And what was ultrasonically cleaned and degreased in the hydrocarbon-type solvent was given the following surface treatment, and the sample for evaluation used as the example of this invention and a comparative example was produced.

[Invention Example 1]
As a film forming means, a sputtering method in which a bias voltage is applied to the base material was adopted, and a hard film and a lubricating film were continuously formed in the same chamber. Regarding the film forming apparatus, first, a DC power source was used as a sputtering power source and a bias power source. In this embodiment, an independent anode is provided to increase the distance of electron movement, and a means for activating the plasma is employed to increase the ionization rate as compared with a normal sputtering apparatus. Although this requirement is not essential to the practice of the present invention, a highly crystalline film can be obtained and the particle morphology of the film can be controlled relatively easily.

Vacuum evacuation is performed with a turbo molecular pump and a rotary pump. Four sputtering evaporation sources are mounted in the apparatus. Then, Al ₆₅ Cr ₃₅ target (atomic ratio) was installed on the cathodes 1 and 2, and Al ₆₀ Cr ₃₇ Si ₃ target (atomic ratio) was installed on the cathodes 3 and 4. Ar, Kr, and N ₂ are used as the introduction gas and introduced from the gas supply port.

  The bias power source is connected to the substrate and independently applies a negative bias voltage to the substrate. The substrate rotates at one revolution per minute and revolves through a fixing jig and a sample holder. The distance between the substrate and the target surface was 50 mm.

Regarding the film forming conditions, first, heating was performed for 60 minutes in a state where the substrate temperature was 500 ° C. by the heater in the film forming apparatus, and the pressure in the vacuum container (chamber) reached 4 × 10 ⁻³ Pa. After that, Ar gas was introduced into the vacuum vessel. Then, a DC bias voltage of −200 V is applied to the substrate, and at this time, 1500 W of electric power is supplied between the independent anode and cathode to increase the Ar plasma density, and the substrate is cleaned with Ar ions for 30 minutes. did.

Next, the pressure in the container is evacuated to 1 × 10 ⁻³ Pa, the temperature of the substrate is kept constant at 450 ° C., and the pressure in the container is kept under constant flow of 300 ml of Ar gas and 200 ml of Kr gas. N ₂ gas was introduced so as to be 600 mPa. Similarly to the cleaning of the substrate, the substrate bias voltage is set to -120 V, the above independent anode voltage is set to -110 V, and 4 kW of sputtering power is supplied to the cathodes 1 and 2 and held for 30 minutes. The cathodes 3 and 4 were supplied with 4 kW of sputtering power and held for 60 minutes to coat an AlCrSiN hard film having a thickness of about 3 μm.

  Subsequently, with respect to both the set values of the base bias voltage of −0V and the anode voltage of −0V, the base bias voltage of −120V and the anode voltage of −110V are continuously applied under the condition of 2V per minute. The inclination was reduced. And after both voltage reached | attained setting value, it hold | maintained on the fixed conditions for 45 minutes, the lubricating film was coat | covered, and the film | membrane of this invention was completed.

  Invention Examples 2 to 4 and Comparative Examples 5 to 7 are the same as the sample preparation method of Invention Example 1 except for the film forming conditions. That is, after coating the hard film corresponding to the present invention, the upper layer film (lubricating film) was coated by performing gradient control with the following set values of the substrate bias voltage and anode voltage as follows.

[Invention Example 2]
The substrate bias voltage was set to -20V and the anode voltage was set to -10V.
[Invention Example 3]
The substrate bias voltage was −40V, and the anode voltage was −30V. In FIG. 1, the scanning electron microscope (henceforth SEM) photograph of a film surface and a fracture surface is shown.
[Invention Example 4]
The substrate bias voltage was −60V, and the anode voltage was −50V. FIG. 2 shows SEM photographs of the coating surface and fracture surface.

[Comparative Example 5]
The substrate bias voltage was −80V, and the anode voltage was −70V. FIG. 3 shows SEM photographs of the coating surface and fracture surface.
[Comparative Example 6]
The substrate bias voltage was −100 V, and the anode voltage was −90 V. FIG. 4 shows SEM photographs of the coating surface and fracture surface.
[Comparative Example 7]
The substrate bias voltage was -120V and the anode voltage was -110V. FIG. 5 shows SEM photographs of the coating surface and fracture surface.

[Comparative Example 8]
For the same base material, an arc ion plating method in which a bias voltage is applied was adopted. For the film forming apparatus, a DC power source was used for the arc power source and the bias power source. In the arc evaporation source, cathodes 1 and 2 (Al ₆₅ Cr ₃₅ target) having the same composition as Example 1 of the present invention and cathodes 3 and 4 (Al ₆₀ Cr ₃₇ Si ₃ target) are mounted. N ₂ is used as the introduced gas. The substrate rotates at 3 revolutions per minute and revolves in the same manner as described above. The distance between the substrate and the target surface was 150 mm. And according to the conditions of Example 1 of the present invention, after the substrate cleaning was performed by applying a DC bias voltage of -200 V, the film was coated under the following conditions.

The pressure in the container was evacuated to 1 × 10 ⁻³ Pa, the base material temperature was kept constant at 450 ° C., and N ₂ gas was introduced so that the pressure in the container was 3 Pa. Then, the substrate bias voltage is set to −120 V, 150 A arc power is supplied to the cathodes 1 and 2 and held for 30 minutes, 150 A arc power is supplied to the cathodes 3 and 4 and held for 60 minutes. The AlCrSiN film having a thickness of about 3 μm corresponding to the hard film of the present invention was coated.

  Then, with respect to the set value of −40 V, which is a bias voltage for covering the next film, the −120 V bias voltage was continuously decreased with a slope of 2 V per minute. Then, after the bias voltage reached the set value, the film was held for 45 minutes, and the film corresponding to the lubricating film of the present invention was coated to complete the film of Comparative Example 8. In FIG. 6, the SEM photograph of the film | membrane surface and fracture surface of the comparative example 8 is shown.

[Invention Example 9]
This is a coated sample (base material-TiAlN coating) according to the same sample preparation method by sputtering as Example 3 except that all of the cathodes 1 to 4 are changed to Ti ₅₀ Al ₅₀ targets (atomic ratio).

[Invention Example 10]
This is a coated sample (base material-AlCrVN coating) according to the same sample preparation method by sputtering as Example 3 except that all of the cathodes 1 to 4 are changed to Al ₆₀ Cr ₃₀ V ₁₀ targets (atomic ratio). .

[Invention Example 11]
A coated sample (base material-TiC film) formed by the same sample preparation method by sputtering as Example 3 except that all of the cathodes 1 to 4 are Ti targets and the introduced gas is changed to acetylene (C ₂ H ₂ ). ).

[Invention Example 12]
A coated sample (base material-AlCrSiN film) formed by the same sputtering method as in Example 3 of the present invention, except that the substrate bias voltage when coating the hard film was set to -140 V and the independent anode voltage was set to -130 V. ).

[Invention Example 13]
All the cathodes 1 to 4 were changed to Al ₆₈ Cr ₂₀ Si ₁₂ target (atomic ratio), and the substrate bias voltage when coating the hard film was set to −140 V, and the independent anode voltage was set to −130 V. It is the coating sample (base material-AlCrSiN film) by the same sample preparation method by sputtering as Example 3 of the present invention.

<Evaluation of coating>
[Evaluation of structure]
The film structure of each sample is compared. Example 3 of the present invention shown in FIG. 1 (bias voltage −40V) has a polygonal roughness form with a sharp tip on the surface, and the needle has an interface in a direction substantially perpendicular to the substrate surface. It is an aggregate of particle-like particles. As the negative bias voltage increases, the sharpness of the surface of the film is reduced. In Example 4 of the present invention (bias voltage -60 V) in FIG. When it becomes Comparative Examples 5-7 (same -80V--120V) of FIGS. 3-5, it has changed to the flat dome shape form, and also the flat form beyond it. And the comparative example 8 of FIG. 6 coat | covered with the arc ion plating method has the unevenness | corrugation by a droplet on the surface, Other surface areas are comparatively smooth.

[Analysis of composition]
About each sample, the composition of the film | membrane was analyzed with the electronic probe microanalyzer (EPMA; JEOL Co., Ltd. JXA-8900R). For analysis, after mirror-polishing the film cross section with the test piece tilted 5 degrees with respect to the outermost surface of the film, select the analysis area of each film so that the average value is as wide as possible within each film on the polished surface. did. The analysis value was measured five times with an acceleration voltage of 15 kV, a sample current of 0.2 μA, and a counting time of 10 seconds, and the average value was obtained. The analysis results are shown in Table 1.

[Measurement of surface roughness]
Ra and Rz of the coating surface were measured with a contact type surface roughness measuring instrument of SURFCOM 480A manufactured by Tokyo Seimitsu. The measurement conditions were as follows.
Evaluation length: 2 mm
Measurement speed: 0.3 mm / s
Cut-off value: 0.8mm
Filter type: Gaussian Measurement range: ± 40μm
Tilt correction: Straight line Cut-off ratio: 300
And Ra and Rz were measured from the obtained profile. The measured value is the average value when measured three times. The results are shown in Table 2.

  The coatings of Invention Examples 1 to 4 and 9 to 13 had a surface roughness of Ra of 0.08 to 0.16 μm and Rz of 0.84 to 1.32 μm. In contrast, the coatings of Comparative Examples 5 to 7 could satisfy 0.08 μm with Ra, but Rz was less than 0.84. The film of Comparative Example 8 coated by the arc ion plating method had a Ra of 0.08 μm and a Rz of 1.64 μm.

[Evaluation of hardness]
The hardness of the film was measured using a nanoindentation device manufactured by Elionix. Since this evaluation apparatus can measure with a minute load, the indentation formed on the measurement object is also minute, and thus the hardness of each layer of the laminated structure film can be measured. First, the cross section of the film in which the test piece was tilted by 5 degrees with respect to the outermost surface of the film was mirror polished. Then, with respect to the polished surface of each layer in the cross section of the film, 10 points were measured for each layer under the measurement conditions of an indentation load of 9.8 mN, a maximum load holding time of 1 second, and a removal rate after loading of 0.098 mN / second, The average value was obtained. The film hardness according to this measurement method is easily influenced by the fine shape of the indenter, the temperature and humidity at the time of measurement, and the surface condition of the sample, and the numerical value obtained cannot be treated as a quantitative value. Is different. Therefore, on the other hand, a single crystal Si reference sample was prepared, and its hardness was measured simultaneously (it was 15 GPa), so that a relative comparison can be made based on the measurement result. The results are shown in Table 3.

  In the film of the present invention, any of the hard films has a high hardness by adjusting the substrate bias voltage. The lubricating film also maintains sufficient hardness. Thereby, the membrane | film | coat of the example of this invention has the outstanding abrasion resistance, and is excellent in the durability as the coating metal mold | die.

[Evaluation of crystallinity]
The film of each sample was subjected to X-ray diffraction, and their crystal structure was examined. The equipment used was an X-ray diffractometer manufactured by Rigaku Corporation, tube voltage 120 kV, tube current 40 μm, X-ray source Cukα, X-ray incident angle 5 degrees, X-ray incident slit 0.4 mm, 2θ 20-90 degrees. Measured with As a result, the samples other than Example 13 of the present invention had a cubic (fcc) structure in which the entire film had an excellent balance between hardness and adhesion. In Invention Example 13, the lubricating film had a hexagonal (hcp) structure. In addition, when the presence of two or more types of crystal structures was identified from each layer, the crystal structure showing the maximum intensity was selected among the crystal structures whose presence was identified. Table 4 shows crystal planes showing the maximum strength in these crystal structures.

The following substrate was coated with the film coated in Example 1 under the same film forming conditions. Details of the substrate are shown below.
Shape: φ10mm x 100mmL
Material: JIS-SKD61 (hardness 45HRC)
Finished surface: adjusted to Ra: 0.05 μm, Rz: 0.5 μm

And the adhesion test of molten aluminum was implemented using said coating | coated sample. Details of the test are shown below. The results are shown in Table 5.
Molten material: JIS-ADC12
Molten metal temperature: 680 ° C
Lubricant: DagCP-503 manufactured by Nippon Atchison Co., Ltd. diluted 80 times with water.
Test method: After immersing the sample in a lubricant for 1 second, the lubricant is removed with air.
Subsequently, it is immersed in the molten metal for 30 seconds, and evaluated by the adhesion state of the molten metal (FIG. 7).

  From Table 5, the film having the surface and internal structure of the present invention is excellent in molten metal adhesion. Among them, a film having a polygonal roughness structure with a sharp tip is particularly excellent in surface impregnation of a lubricant (release agent), and adhesion of molten aluminum is not recognized.

Claims (9)

  A coating mold in which a film is coated on the surface of a mold substrate by a sputtering method, and the film is coated on a hard film made of at least one of nitride, carbide, and carbonitride, and directly thereon. The lubricating film is made of at least one of nitride, carbide, and carbonitride, and the lubricating film has a surface roughness of arithmetic average roughness Ra: 0.08 μm or more and maximum height Rz: 0.84 μm. A coated mold excellent in lubricant adhesion and durability, which is an aggregate of acicular particles having an interface in a direction substantially perpendicular to the surface of the mold base.   The coated mold excellent in lubricant adhesion and durability according to claim 1, wherein the hard film and the lubricating film have substantially the same composition.   3. The coated mold excellent in lubricant adhesion and durability according to claim 1 or 2, wherein the tip of the acicular particles has a polygonal shape on the surface of the lubricating film.   The lubricant film according to any one of claims 1 to 3, wherein the lubricant film has a cubic crystal structure and has a maximum strength at (111) in X-ray diffraction. Coated mold.   The lubricant film according to any one of claims 1 to 4, wherein the hard film has a cubic crystal structure and has a maximum strength at (200) in X-ray diffraction. Coated mold.   The hard film and / or the lubricating film is made of a nitride, carbide, or carbonitride of at least one element selected from Ti, Cr, Al, Si, W, Nb, Mo, V, B, and Hf. The coated mold excellent in lubricant adhesion and durability according to any one of claims 1 to 5, wherein the coated mold is one or more kinds.   A method for producing a coated mold in which a surface of a mold base is coated with a film by a sputtering method, the film comprising a hard film made of at least one of nitride, carbide, and carbonitride, and immediately above The lubricating film is made of at least one of nitride, carbide, and carbonitride coated on the surface, and the lubricating film is coated by a sputtering method in which the substrate bias voltage at the time of coating is set to −0V to −60V. A method for producing a coated mold excellent in lubricant adhesion and durability.   8. The coated mold excellent in lubricant adhesion and durability according to claim 7, wherein the hard film is coated by a sputtering method in which the substrate bias voltage at the time of coating is over -60 V to -160 V. Manufacturing method.   The method for producing a coated mold excellent in lubricant adhesion and durability according to claim 7 or 8, wherein the hard film and the lubricating film have substantially the same composition.