JPH07310175A - Hard film and coating method using the same film - Google Patents

Abstract

PURPOSE:To form a hard film excellent in the effect of protecting the base material from high temp. fluidizing substance such as the molten metal of aluminum alloys, the liq. fused materials of rubber and the liq. fused materials of thermoplastic resin even if being repeatedly brought into contact with the same and in which dimensional change, strains or the like are hard to generate on the base material at the time of its formation. CONSTITUTION:This hard film is constituted of a chromium compound film formed by a physical vapor deposition method and a titanium compound film formed by a physical vapor deposition method on the chromium compound film directly or via a mixed film constituted of a chromium compound and a titanium compound. Furthermore, the coating method using the hard film is executed by forming the chromium compound film on the prescribed surface of the base material by a physical vapor deposition method and forming the titanium compound film by a physical vapor deposition method on the chromium compound film directly or via a mixed film constituted of a chromium compound and a titanium compound to coat the prescribed surface of the base material with the hard film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating and a coating method using the coating, and in particular, a hard coating suitable as a coating for protecting a mold for aluminum alloy casting or the like and parts thereof (mold pins, etc.). The present invention relates to a coating and a coating method using the hard coating.

[0002]

2. Description of the Related Art A die for casting an aluminum alloy and its parts (die pins, etc.) are generally formed by forming an iron-based alloy represented by hot die steel into a desired shape (hereinafter referred to as a mother piece). It is formed by coating a predetermined surface of a material) with a hard coating. The hard coating is to prevent seizure, galling, breakage, etc. due to contact with the molten aluminum alloy (temperature is about 600 to 800 ° C.), and as the hard coating, a single layer has been conventionally used. Structure titanium compound film (TiN film, TiCN film, etc.) or multi-layered titanium compound film (lamination of TiC film and TiN film, etc.)
Is widely used. As the thickness of the titanium compound film increases, the shielding effect of the chemical reaction between the base material and the molten metal increases. Therefore, it is preferable to form a thick titanium compound film in order to prevent corrosion and erosion damage of the base material due to a chemical reaction between the base material and the molten metal. Further, in order to obtain a titanium compound film having high adhesion to the base material, it is desired to reduce the compressive residual internal stress of the titanium compound film.

For these reasons, the titanium compound film has a film thickness of about 5 conventionally formed by the chemical vapor deposition method.
-10 μm titanium compound films have been utilized. However, the chemical vapor deposition method has a processing temperature as high as about 1000 ° C., and therefore has a drawback that a base material is likely to undergo dimensional change, distortion, and the like when forming a titanium compound film. Therefore, in recent years, titanium compound films formed by the physical vapor deposition method have been widely used. According to the physical vapor deposition method, the titanium compound film can be formed at a processing temperature of 500 ° C. or less, so that the base material is unlikely to undergo dimensional change or distortion during the formation of the titanium compound film.

[0004]

However, the titanium compound film formed by the physical vapor deposition method has a relatively large compressive residual internal stress, and if the film thickness is made thicker than 5 μm, the adhesion with the base material is impaired or chipping or the like occurs. May occur easily. Therefore, when the titanium compound film is formed as the hard coating film by physical vapor deposition, the upper limit of the film thickness is limited to about 5 μm. However, in such a titanium compound film, a film between the base material and the molten metal is formed. Low shielding effect of chemical reaction,
That is, there is a drawback that the effect of preventing melting loss is low.

In addition, since the titanium compound film has a relatively low hardness at high temperature, it is in an environment where molten metal containing hard particles (Si particles, etc.) (aluminum alloy molten metal, etc.) collides at high speed and causes abrasive wear. There is also a drawback that the abrasion resistance is insufficient. Furthermore, since the titanium compound film has a relatively low compatibility of the coefficient of thermal expansion with the steel of the base material, it will not crack when it is used in a device or member that is subject to a large temperature difference such as an aluminum alloy casting mold and its parts. Is relatively easy to occur. When cracks occur, the molten metal and the base material react directly with each other, resulting in damage to the base material.
In addition, since the titanium compound film is relatively inferior in oxidation resistance,
The coating film is relatively damaged due to the falling off of the oxidized portion, and when titanium oxide is formed on the surface, it is easily wet by the molten aluminum alloy.

An object of the present invention is to provide an excellent effect of protecting the base material from the high temperature substance even when it is repeatedly contacted with a high temperature fluid substance such as a molten aluminum alloy, and to prevent a dimensional change in the base material during formation. A hard coating that does not easily generate distortion,
It is to provide a coating method with this hard coating.

[0007]

The hard coating of the present invention which achieves the above object comprises a chromium compound film formed by physical vapor deposition and a chromium compound and a titanium compound directly on the chromium compound film. It is characterized by comprising a titanium compound film formed by a physical vapor deposition method through a mixed film.

Further, the coating method of the present invention which achieves the above-mentioned object, is that a chromium compound film is formed on a predetermined surface of a base material by a physical vapor deposition method, and then directly on the chromium compound film or with a chromium compound and a titanium compound. By forming a titanium compound film by a physical vapor deposition method through a mixed film consisting of
A predetermined surface of the base material is coated with a hard coating.

The present invention will be described in detail below. First, the hard coating film of the present invention will be described. As described above, the hard coating was formed by physical vapor deposition on the chromium compound film formed by physical vapor deposition and directly on the chromium compound film or through the mixed film of the chromium compound and the titanium compound. And a titanium compound film.

Here, as a specific example of the chromium compound film, the following formula (I) is used.

[Chemical 1] (In the formula, x represents a numerical value within the range of 0.4 to 1.5.)
Chromium nitride represented by or the following formula (II)

[Chemical 2] (In the formula, x represents a numerical value within the range of 1.0 to 2.0.)
An oxide of chromium represented by the following formula (III)

[Chemical 3] (In the formula, x represents a numerical value within the range of 1.0 to 2.0, and y
Indicates a numerical value within the range of 0.4 to 1.1. ) A film made of oxynitride of chromium represented by

Although this chromium compound film can be formed by a chemical vapor deposition method such as thermal CVD, it is difficult to handle the raw material gas in the chemical vapor deposition method, and the base material undergoes dimensional change and distortion during film formation. easy. For this reason, in the present invention, the above chromium compound film is subjected to physical vapor deposition such as reactive vapor deposition, reactive sputtering, reactive ion plating (including HCD (hollow cathode discharge) reactive ion plating). Established by law. Among these physical vapor deposition methods, the reactive ion plating method is particularly preferable in terms of controllability of the crystal structure of the formed film and adhesion strength of the film to the base material. Details of film forming conditions for the chromium compound film will be described later.

The thickness of the chromium compound film may be the thickness of the titanium compound film provided directly on the chromium compound film or through the mixed film of the chromium compound and the titanium compound, the intended use of the hard coating film, etc. 2 depending on
It is preferable that the predetermined value is within a range of ˜20 μm. When the film thickness is less than 2 μm, the effect of shielding the chemical reaction between the base material and the molten metal tends to be insufficient. Further, the wear resistance of the hard coating of the present invention largely depends on the high temperature hardness of the chromium compound film, and if the thickness of the chromium compound film is less than 2 μm, it is difficult to obtain a hard coating having high wear resistance. is there. On the other hand, the film thickness is 2
If it exceeds 0 μm, the productivity of the hard coating decreases and the chipping resistance also decreases. The particularly preferable film thickness of the chromium compound film is in the range of 3 to 10 μm.

A specific example of the titanium compound film formed on the above-mentioned chromium compound film is represented by the following formula (IV)

[Chemical 4] (In the formula, x represents a numerical value within the range of 0.5 to 1.5.)
Titanium nitride represented by

[Chemical 5] (In the formula, x and y are each independently 0.5 to 1.5.
Indicates a value within the range. ) Titanium carbonitride represented by the following formula (VI)

[Chemical 6] (In the formula, x represents a numerical value within the range of 0.5 to 2.0, and y
Indicates a numerical value within the range of 0.5 to 1.5. ) Titanium oxynitride represented by), or the following formula (VII)

[Chemical 7] (In the formula, x represents a numerical value within the range of 0.5 to 2.0, and y
And z each independently represent a numerical value within the range of 0.5 to 1.5. A film made of titanium oxynitride carbide represented by

This titanium compound film can also be formed by the chemical vapor deposition method, but it is preferably provided by the physical vapor deposition method, particularly the reactive ion plating method, for the same reason as the above-mentioned chromium compound film. Details of the film forming conditions for the titanium compound film will be described later.

The thickness of the titanium compound film varies depending on the thickness of the chromium compound film provided under the titanium compound film and the intended use of the hard coating, but is 1 to 5 μm.
It is preferable that the predetermined value is within the range. Film thickness is 1 μm
If the amount is less than the above, the effect of shielding the chemical reaction between the base material and the molten metal and the abrasion resistance of the obtained hard coating tend to be insufficient. on the other hand,
When the film thickness exceeds 5 μm, the compressive residual internal stress inside the film increases and the adhesiveness thereof decreases, which is not preferable. The particularly preferable film thickness of the titanium compound film is in the range of 2 to 4 μm.

The above-mentioned titanium compound film may be directly formed on the above-mentioned chromium compound film. In this case, the physical properties (coefficient of thermal expansion, elastic modulus, toughness value) of the chromium compound film and the titanium compound film are used. , Strength, thermal conductivity, etc.), a large thermal stress may be generated in the vicinity of the interface between the titanium compound film and the chromium compound film during the heating-cooling process, resulting in destruction of the film or interface. Therefore, it is more preferable that the titanium compound film described above is formed on the chromium compound film described above through a mixed film of a chromium compound and a titanium compound.

Specific examples of the chromium compound and the titanium compound forming the above mixed film include the above formulas (I) to
Examples thereof include a chromium compound represented by (III) and a titanium compound represented by the above formulas (IV) to (VII). The composition of the chromium compound forming the mixed film may be different from the composition of the chromium compound film which is the base of the mixed film, but it should be the same as the composition of the chromium compound film in order to reduce the above-mentioned thermal stress. Is particularly preferable. Similarly,
It is particularly preferable that the composition of the titanium compound forming the mixed film is the same as the composition of the titanium compound film provided on the mixed film.

The composition distribution in the mixed film may be substantially uniform in the thickness direction, or the ratio of the titanium compound gradually increases from the chromium compound film side to the titanium compound side. Good. In the case of a composition distribution in which the ratio of the titanium compound gradually increases, the change in the ratio of the titanium compound may be continuous or stepwise. Regardless of which composition distribution is used, the mixed film is preferably formed by a physical vapor deposition method, particularly a reactive ion plating method, for the same reason as the above-described chromium compound film and titanium compound film. The details of the conditions for forming the mixed film will be described later.

The thickness of the mixed film is preferably in the range of 0.5 to 10 μm. If the film thickness is less than 0.5 μm, the thermal stress relaxation effect of the mixed film tends to be insufficient. On the other hand, if the film thickness exceeds 10 μm, it will be difficult to fully utilize the respective characteristics of the chromium compound film and the titanium compound film. A particularly preferable film thickness of the mixed film is in the range of 0.5 to 5 μm.

By forming the above-mentioned titanium compound film directly on the above-mentioned chromium compound film or through the above-mentioned mixed film, a desired hard coating film can be obtained.
The film thickness of the hard coating can be appropriately changed according to its application and the like, but it is preferably within the range of 3 to 25 μm. If the film thickness of the hard film is less than 3 μm, it will be difficult to obtain the desired hard film regardless of the combination of the film thicknesses of the chromium compound film and the titanium compound film. on the other hand,
If the film thickness exceeds 25 μm, the productivity and the chipping resistance decrease. A particularly preferred film thickness of the hard coating is 5 to 15 μ.
It is within the range of m. There are many combinations of the chromium compound film and the titanium compound film in the hard coating film of the present invention, but the combination of the CrN film and the TiN film is most preferable.

The hard coating of the present invention comprises SKD61, YXR
It has excellent adhesiveness (adhesion) to the base material made of iron-based alloys such as 33 and other hot-alloy tool steels and hot-die steels, and also adheres to the base material made of copper alloys (adhesion). Power) is also excellent. In addition, this hard coating protects the base material from the high temperature substances even when repeatedly contacted with high temperature fluid substances such as molten aluminum alloy, liquid melt of rubber, liquid melt of thermoplastic resin, etc. The effect of doing is excellent. Furthermore, since each film constituting the hard coating is formed by the physical vapor deposition method, it is unlikely that the base material undergoes dimensional change or distortion during its formation.

Therefore, the hard coating of the present invention is suitable as a coating for protecting the base material of the aluminum alloy casting mold and the base material of its parts (mold pins, etc.), as well as the rubber molding mold, As a coating to protect the base material of various dies such as plastic molding dies, press dies, food machine dies, warm forging dies, and the base materials of those parts (die pins, etc.) Is also suitable.

Further, since the surface of the hard coating of the present invention is made of the titanium compound film, the mold having the hard coating on the surface and the parts thereof have excellent releasability from the molded product. For this reason, the raw material (such as molten aluminum alloy) attached to the surface of the mold or its components during molding can be separated relatively easily after cooling. This facilitates regular maintenance of the mold and its parts in the actual casting operation.

The coating with the hard coating of the present invention is carried out by the method of the present invention described below in order to prevent the base material from undergoing dimensional change and distortion during the formation of the hard coating. As described above, the method of the present invention is, as described above, after forming a chromium compound film on a predetermined surface of a base material by a physical vapor deposition method, directly on the chromium compound film or through a mixed film composed of a chromium compound and a titanium compound. By forming a titanium compound film by a physical vapor deposition method, a predetermined surface of the base material is covered with a hard coating.

Here, specific examples of the chromium compound film and the titanium compound film and the film thicknesses of these films are as exemplified in the hard coating film of the present invention described above. In addition, specific examples of the mixed film to be interposed between the chromium compound film and the titanium compound film as necessary, and the composition distribution and film thickness of this film are also exemplified in the hard coating film of the present invention already described. As I did.

Specific examples of the physical vapor deposition method applied when forming the above-mentioned chromium compound film or titanium compound film include a reactive vapor deposition method, a reactive sputtering method, a reactive ion plating method (HCD (hollow cathode discharge). ), Including the reactive ion plating method), but the reactive ion plating method is particularly preferable as described above. Also, the above-mentioned mixed film is preferably formed by the physical vapor deposition method as described above, and particularly preferably formed by the reactive ion plating method.

The film forming conditions for forming the chromium compound film are different depending on the type of physical vapor deposition method to be applied and the composition of the target chromium compound film, and therefore cannot be specified unconditionally. For example, HCD reactive ions are used. The following conditions are given as an example of film forming conditions for forming a chromium nitride film by the plating method. Film forming conditions Cr vaporized metal, plasma voltage 30 to 60 V, plasma current 150 to 250 A, Ar gas flow rate 30 to 80 SCCM, reaction gas (N ₂ gas) flow rate 50 to 250 SCCM, substrate bias voltage 30 to 250 V, vacuum degree 0. 8 x 10 ^{-3 to} 5 x 1
0 ^-3 Torr.

Further, as an example of film forming conditions for forming a chromium oxide film by the HCD reactive ion plating method, O ₂ gas is used as a reaction gas instead of N ₂ gas, and its flow rate is 50-150 SCCM,
Other conditions may be the same as the above-mentioned conditions for forming the chromium nitride film. Then, as an example of film forming conditions for forming a chromium oxynitride film by the HCD reactive ion plating method, O ₂ gas and N ₂ gas are used as a reaction gas, and an O ₂ gas flow rate is 50.
～150SCCM, the N ₂ gas flow rate and 50～250SCCM,
Other conditions may be the same as the above-mentioned conditions for forming the chromium nitride film.

On the other hand, the film forming conditions for forming the titanium compound film are different depending on the type of physical vapor deposition method to be applied and the composition of the target titanium compound film, and therefore cannot be specified unconditionally. For example, HCD reaction The following conditions may be mentioned as an example of film forming conditions for forming a titanium nitride film by the reactive ion plating method. Deposition conditions: evaporated metal Ti, plasma voltage 30 to 60 V, plasma current 200 to 300 A, Ar gas flow rate 30 to 80 SCCM, reaction gas (N ₂ gas) flow rate 50 to 250 SCCM, substrate bias voltage 30 to 250 V, vacuum degree 0. 8 x 10 ^{-3 to} 5 x 1
0 ^-3 Torr.

In addition, as an example of film forming conditions for forming a carbonitride film of titanium by the HCD reactive ion plating method, C ₂ H ₂ gas and N ₂ are used as reaction gases.
₂ gas is used and the flow rate of C ₂ H ₂ gas is 50 to 20
The conditions are 0 SCCM, the N ₂ gas flow rate is 50 to 250 SCCM, and other conditions are the same as the above-described titanium nitride film forming conditions. As an example of film forming conditions for forming a titanium oxynitride film by the HCD reactive ion plating method, O ₂ gas and N ₂ gas are used as a reaction gas and an O ₂ gas flow rate is 50 to 150 SCCM.
The N ₂ gas flow rate is 50 to 250 SCCM, and the other conditions are the same as the above-described titanium nitride film forming conditions. Then, as an example of film forming conditions for forming a titanium oxynitride carbide film by the HCD reactive ion plating method, O ₂ gas, N ₂ gas and C ₂ H ₂ gas are used as a reaction gas and ₂ gas flow rate 5
0～150SCCM, the N ₂ gas flow rate 50~250SCCM, C
_{The 2} H ₂ gas flow rate is 50 to 200 SCCM, and the other conditions are the same as the above-described titanium nitride film forming conditions.

Further, the film forming conditions for forming the mixed film are different depending on the type of physical vapor deposition method to be applied and the composition of the intended mixed film, and therefore cannot be specified unconditionally. For example, HCD reactive ions are used. The following film forming conditions are given as an example of film forming conditions for forming a mixed film of chromium nitride and titanium nitride by a plating method.

Film forming conditions Plasma voltage of evaporated metal Cr and Ti, Cr side 30-
60 V, Ti side plasma voltage 30 to 60 V, Cr side plasma current 150 to 250 A, Ti side plasma current 200 to 300 A, Ar gas flow rate 30 to 80 SCCM, reaction gas (N ₂ gas) flow rate 50 to 250 SCCM, substrate bias Voltage 30 to 250 V, vacuum degree 0.8 × 10 ^{−3 to} 5 × 10
^-3 Torr.

As described above, the chromium compound film, the mixed film if necessary, and the titanium compound film are sequentially formed on the predetermined surface of the base material by the physical vapor deposition method, whereby the predetermined surface of the base material is made to have a desired hardness. It can be covered by a coating. The thickness of the hard coating can be appropriately changed according to its application, etc., but as described in the hard coating of the present invention described above, it is within the range of 3 to 25 μm, and particularly 5 to 15 μm. It is preferable to set the inside.

[0034]

The hard coating of the present invention is in contact with the base material by the chromium compound film. This chromium compound film is superior in adhesion to the base material (iron-based alloy or copper alloy) than the titanium compound film, and since the residual internal stress is small, it is easy to thicken the film even when formed by physical vapor deposition. is there. In addition, the titanium compound film provided directly on this chromium film or through a mixed layer of a chromium compound and a titanium compound is used as a molten aluminum alloy, a liquid melt of rubber, a liquid melt of a thermoplastic resin, or the like. Low affinity and reactivity with high temperature fluid substances. Therefore, by setting the film thicknesses of the chromium compound film and the titanium compound film to predetermined values, the adhesion with the base material is high and the shielding effect of the chemical reaction between the high temperature fluid substance and the base material is high. A hard coating can be easily obtained, which makes it possible to easily prevent corrosive erosion of the base material due to the chemical reaction between the high temperature fluid substance and the base material.

Further, since the chromium compound film is excellent in oxidation resistance at high temperatures, the film damage caused by the falling off of the oxidized part is small. Since the chromium compound film is excellent in high temperature hardness, it has high wear resistance against abrasive wear. Further, since the chromium compound film has a high compatibility of the coefficient of thermal expansion with the base steel, cracks are less likely to occur even when subjected to a thermal cycle with a large temperature difference. Therefore,
Even if the titanium compound film is eroded due to cracks or the like in the titanium compound film due to repeated contact with the high temperature fluid substance, the direct reaction between the high temperature fluid substance and the base material means that the chromium compound film As a result, the base material is less damaged.

On the other hand, the titanium compound film has low affinity and reactivity with the above-mentioned high temperature fluid substance, as described above. Therefore, for example, when the hard coating of the present invention is provided on a predetermined surface of the base material of the mold to form the mold, the mold has excellent releasability from the molded product. For this reason, the raw materials (such as molten aluminum alloy) attached to the surface of the mold and its parts during molding.
Can be peeled off relatively easily after cooling. This facilitates regular mold maintenance in the actual casting operation.

As described above, in the hard coating of the present invention, the chromium compound film and the titanium compound film properly play different roles. Excellent in protecting the base material. Further, since each film constituting the hard coating is provided by the physical vapor deposition method, it is unlikely that the base material undergoes dimensional change or distortion during its formation.

When a mixed layer composed of a chromium compound and a titanium compound is interposed between the chromium compound film and the titanium compound film, the physical properties of the chromium compound film and the titanium compound film (coefficient of thermal expansion, elasticity, etc.) Rate, toughness value, strength, thermal conductivity, etc.), it is possible to suppress the generation of a large thermal stress in the vicinity of the interface between these films during the heating-cooling process. Therefore, by forming a hard film having a mixed film, it is possible to reduce the possibility that the hard film will be destroyed when subjected to a thermal cycle with a large temperature difference such as repeated contact with the high temperature fluid substance. be able to.

[0039]

EXAMPLES Examples of the present invention will be described below. Example 1 First, SK having a hardness of HRC48 after quenching and tempering treatment
A rod-shaped material made of D61 having a diameter of 10 mm and a length of 50 mm was prepared, and a CrN film having a thickness of 3.5 μm was formed on the side surface (outer peripheral surface) of the rod-shaped material by the HCD reactive ion plating method. The film forming conditions at this time are as follows.・ Film forming conditions Evaporated metal Cr, plasma voltage 50V, plasma current 20
0 A, Ar gas flow rate 35 SCCM, reaction gas (N ₂ gas) flow rate 100 SCCM, substrate bias voltage 50 V, vacuum degree 2.2.
× 10 ^-3 Torr.

Next, a TiN film having a film thickness of 1 μm was formed on the above CrN film by the HCD reactive ion plating method. The film forming conditions at this time are as follows.・ Film forming conditions Evaporated metal Ti, plasma voltage 50V, plasma current 27
0 A, Ar gas flow rate 35 SCCM, reaction gas (N ₂ gas) flow rate 150 SCCM, substrate bias voltage 50 V, vacuum degree 2.0
× 10 ^-3 Torr.

By sequentially forming the CrN film and the TiN film as described above, the side surface of the rod-shaped article described above was covered with the intended hard coating. Regarding the hard coating thus provided, in examining the effect of the hard coating to protect the base material (the above-mentioned rod-shaped material), the acceleration using a molten metal of aluminum alloy (ADC12) (hereinafter, simply referred to as molten metal) The test was conducted, and when the melting damage was observed for the first time, the melting damage area ratio of the sample surface was obtained.

In carrying out the acceleration test, first, a rod-shaped object (hereinafter referred to as a sample) after a hard coating is provided.
Was preheated to 250 ° C. Separately, melts having different temperatures of 650 ° C., 700 ° C., and 750 ° C. were prepared. Then, after immersing the sample in the molten metal for 1 hour, pulling it up, allowing it to cool to room temperature, removing the aluminum alloy adhering to the surface of the sample with an aqueous NaOH solution, and visually observing the presence or absence of melting damage. An acceleration test was performed by sequentially performing the molten metal starting from a low temperature.

As a result of this acceleration test, melting loss was observed for the first time after observation after immersion in the molten metal at 750 ° C.
The erosion area ratio of the sample surface at this time was determined as follows. First, after removing the aluminum alloy, Si (which was contained in the aluminum alloy) on the surface of the sample was removed with a hydrofluoric acid-based etchant, and then a photographic image with a magnification of 4.10 was taken. Then, from this photographic image, two areas corresponding to 120 / 4.1 (mm) × 30 / 4.1 (mm) in actual size were taken, and aluminum alloy adhered to each area due to occurrence of melting loss. The area ratio (total area of the erosion area / total surface area of the sample within the trace range) of the erosion area in each trace drawing is traced independently by tracing the existing area (hereinafter referred to as the erosion area). I asked. However, the total area of the erosion portion and the total surface area of the sample are both the area in plan view, that is, the area in the trace drawing. Then, the average value of the area ratios of the erosion portion in the above two ranges was calculated and used as the erosion area ratio. The results are shown in Table 1.

Example 2 First, a rod-shaped material having the same quality and the same shape as the rod-shaped material used in Example 1 was prepared, and the side surface (outer peripheral surface) of the rod-shaped material was coated with a film having a thickness of 3 μm by HCD reactive ion plating. CrN
A film was formed. The film forming conditions at this time are as follows.・ Film forming conditions Evaporated metal Cr, plasma voltage 50V, plasma current 20
0 A, Ar gas flow rate 30 SCCM, reaction gas (N ₂ gas) flow rate 100 SCCM, substrate bias voltage 50 V, vacuum degree 2.0
× 10 ^-3 Torr.

Then, a mixed film of CrN and TiN having a film thickness of 1 μm was formed on the CrN film by the HCD reactive ion plating method. The film forming conditions at this time are as follows. -Film forming conditions Plasma voltage of evaporated metal Cr and Ti, Cr side 50
V, Ti side plasma voltage 55 V, Cr side plasma current 200 A, Ti side plasma current 250 A, Ar gas flow rate 30 SCCM, reaction gas (N ₂ gas) flow rate 150 SCCM,
Substrate bias voltage 50V, vacuum degree 2.0 × 10 ⁻³ Torr.
The composition distribution in the thickness direction of the above mixed film is substantially uniform.

Next, a TiN film having a film thickness of 1.5 μm was formed on the above mixed film by the HCD reactive ion plating method. The film forming conditions at this time are as follows.・ Film forming conditions Evaporated metal Ti, plasma voltage 55V, plasma current 25
0 A, Ar gas flow rate 30 SCCM, reaction gas (N ₂ gas) flow rate 120 SCCM, substrate bias voltage 50 V, vacuum degree 2.0
× 10 ^-3 Torr.

By sequentially forming the CrN film, the mixed film and the TiN film as described above, the side surface of the rod-shaped article described above was covered with the intended hard film. Regarding the hard coating thus provided, in examining the effect of this hard coating for protecting the base material (the rod-shaped material),
An acceleration test under the same conditions as in Example 1 was performed, and the melt-dissipation area ratio at the time when melt-dissipation was observed for the first time was determined by the same method as in Example 1. The results are shown in Table 1.

Comparative Example 1 A TiC film having a film thickness of 3 μm provided by a thermal CVD method,
Similarly, a T film having a thickness of 2.5 μm formed by the thermal CVD method
For a hard coating having a two-layer structure including an iN film, the protective effect of the base material of the hard coating was examined by an acceleration test under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 2 Example 1 except that a TiN film having a thickness of 1.7 μm was provided as a hard coating by the HCD reactive ion plating method.
In the same manner as in (1), a rod-shaped article whose side surface was coated with a hard coating was obtained. The film forming conditions at this time are as follows.・ Film forming conditions Evaporated metal Ti, plasma voltage 55V, plasma current 25
0 A, Ar gas flow rate 60 SCCM, reaction gas (N ₂ gas) flow rate 150 SCCM, substrate bias voltage 50 V, vacuum degree 2.0
× 10 ^-3 Torr. After that, the protective effect of the base material (the above-mentioned rod-shaped material) possessed by this hard coating was examined by an acceleration test under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 3 Example 1 except that a CrN film having a thickness of 3.5 μm was provided as a hard coating by the HCD reactive ion plating method.
In the same manner as in (1), a rod-shaped article whose side surface was coated with a hard coating was obtained. The film forming conditions at this time are as follows.・ Film forming conditions Evaporated metal Cr, plasma voltage 50V, plasma current 20
0 A, Ar gas flow rate 30 SCCM, reaction gas (N ₂ gas) flow rate 100 SCCM, substrate bias voltage 50 V, vacuum degree 2.0
× 10 ^-3 Torr. After that, the protective effect of the base material (the above-mentioned rod-shaped material) possessed by this hard coating was examined by an acceleration test under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 4 A rod-shaped coating having a side surface coated with a hard coating was carried out in the same manner as in Example 1 except that a DLC film (diamond-like carbon film) having a film thickness of 1.0 μm was provided as the hard coating by the ion plating method. I got a thing. The film forming conditions at this time are as follows.・ Film forming conditions Plasma voltage 50V, plasma current 0.4A, Ar gas flow rate 20SCCM, reaction gas (C ₆ H ₆ gas) flow rate 15SCC
M, substrate bias voltage 1000V, vacuum degree 1.8 × 10
^-3 Torr. After that, the protective effect of the base material (the above-mentioned rod-shaped material) possessed by this hard coating was examined by an acceleration test under the same conditions as in Example 1. The results are shown in Table 1.

[0052]

[Table 1]

As is clear from Table 1, in each of the samples obtained in Example 1 and Example 2, no melting loss was observed at the coated portion when immersed in the molten metal at 650 ° C and 700 ° C.
Melt damage was observed at the coated portion only when immersed in the melt at 50 ° C., but the melt loss area ratio was as small as 0.67% (Example 1) and 0.34% (Example 2). From this, it is understood that the hard coatings formed in Examples 1 and 2 are excellent in the effect of protecting the base material from the molten metal. In addition, in the samples obtained in Example 1 and Example 2, dimensional change and distortion did not occur in the base material during formation of the hard coating.

On the other hand, even in the samples obtained in Comparative Example 1 and Comparative Example 2, no erosion was observed in the coated part when immersed in the molten metal at 650 ° C. and 700 ° C. Although the erosion rate was observed in No. 1, the erosion area ratio was 16.10% (Comparative Example 1), 77.11%
It was as large as (Comparative Example 2). Further, in the sample obtained in Comparative Example 3, no erosion loss was observed at the coated portion when immersed in the molten metal at 650 ° C., but erosion loss was observed at the coated portion when immersed in the molten metal at 700 ° C. Area ratio is 2
It was as large as 4.91%. Then, in the sample obtained in Comparative Example 4, when the sample was immersed in the molten metal at 650 ° C., a erosion loss was observed at the coated portion, and the erosion area ratio was as large as 15.92%.

High Chromium Compound Film and Titanium Compound Film
C, which was formed into a film by the temperature hardness HCD reactive ion plating method
FIG. 1 shows the micro Vickers hardness at 25 ° C. to 600 ° C. for each of the rN film, the TiN film, and the TiC film. As is clear from FIG. 1, the high-temperature hardness of the chromium compound film (CrN film) (hardness in a high-temperature environment of approximately 500 ° C. or higher) is equal to that of the titanium compound film (TiN film and TiN film).
It is higher than the high temperature hardness of C film).

[0056]

As described above, the hard coating film of the present invention is excellent in the effect of protecting the base material from the high temperature fluid substance even when repeatedly contacted with the high temperature fluid substance such as the molten aluminum alloy. ing. Further, the hard coating film of the present invention can be easily formed without causing a dimensional change or distortion in the base material. Therefore, according to the present invention, it becomes possible to easily extend the life of an instrument or the like, such as a mold and its parts, which is repeatedly brought into contact with a high temperature fluid substance such as a molten aluminum alloy.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between temperature and micro Vickers hardness for each of a CrN film, a TiN film, and a TiC film formed by the HCD reactive ion plating method.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kurt Schadel 8-19-8 Nishi, Shiraoka-cho, Minami Saitama-gun, Saitama Nanotech Co., Ltd. (72) Kenji Sato 6-14-5-202, Sagimiya, Nakano-ku, Tokyo

Claims (5)

[Claims] 1. A chromium compound film formed by a physical vapor deposition method, and a titanium compound film formed by a physical vapor deposition method directly on the chromium compound film or through a mixed film of a chromium compound and a titanium compound. Hard coating characterized by 2. The chromium compound film comprises one selected from the group consisting of chromium nitride, chromium oxide and chromium oxynitride, and the chromium compound film has a thickness of 2 to 20 μm. The hard coating according to claim 1, which is within the range. 3. The titanium compound film is made of one selected from the group consisting of titanium nitride, titanium carbonitride, titanium oxynitride and titanium oxynitride carbide, and The hard coating film according to claim 1 or 2, wherein the film thickness is in the range of 1 to 5 µm. 4. A titanium compound is formed on a predetermined surface of a base material by a physical vapor deposition method and then a titanium compound is formed on the chromium compound film directly or through a mixed film of a chromium compound and a titanium compound by a physical vapor deposition method. A method for coating with a hard coating, which comprises coating a predetermined surface of the base material with a hard coating by forming a film. 5. The method according to claim 4, wherein the physical vapor deposition method is a reactive ion plating method.