JP2010214551A - Wear resistant tool member excellent in heat resistance and durability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wear resistant tool member excellent in heat resistance and durability suitable for a cutting tool for free-cutting steel or the like. <P>SOLUTION: In the wear resistant tool member, a TiN hard film, a diamond-like carbon film containing Al, and an Al<SB>2</SB>O<SB>3</SB>film are formed in this order from a surface side of a tool base on the tool base. An Al content in the diamond-like carbon film containing Al is 5 to 30 atomic%. Preferably the diamond-like carbon film containing Al contains 5 to 15 atomic% Al at the interface with the TiN hard film, and 20 to 30 atomic% Al at the interface with the Al<SB>2</SB>O<SB>3</SB>film. The diamond-like carbon film containing Al preferably also has gradient composition where the Al content in the diamond-like carbon film containing Al gradually increases from a TiN hard film side toward an Al<SB>2</SB>O<SB>3</SB>film side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wear-resistant tool member, and more particularly to a wear-resistant tool member excellent in heat resistance and durability, which is suitable for use as a long-time cutting tool member such as free-cutting steel.

Conventionally, it is known to form a diamond-like carbon (hereinafter referred to as DLC) film on a tool base in order to improve wear resistance and lubricity of a tool member such as a cutting tool.
For example, Patent Document 1 discloses a tool member in which a TiN film, a TiCN film, and a TiAlN film are formed on a tool base, and a DLC film is formed as a single layer thereon. In Patent Document 2, a tool base is disclosed. Further, there is disclosed a wear-resistant member and a sliding member in which DLC films are alternately laminated through Si, Ge, SiC, SiO ₂ , and Al ₂ O ₃ buffer layers.

Japanese Patent No. 3372493 Japanese Patent No. 3246513

DLC film is excellent in slidability and wear resistance, so it is used as a protective film for various sliding members and wear-resistant members. In the field of tool members such as cutting tools, its wear resistance, It is used as a hard coating for improving slidability.
By the way, in recent years, the performance of cutting technology has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and accordingly, cutting is performed under more severe conditions. At the same time, there is a demand for general-purpose cutting tools that can handle various types of work materials. However, the conventional sliding members and wear-resistant members are used as cutting tools. In this case, since the heat resistance temperature of the DLC film is about 450 ° C., the characteristics of the DLC film are lost due to high heat load in long-time cutting such as free-cutting steel, and the wear proceeds rapidly. The present situation is that the service life is reached in a relatively short time, and the characteristics of the DLC film as a hard coating are not fully utilized.

Therefore, from the above viewpoint, the present inventors have used a hard coating to further improve the wear resistance of the wear-resistant tool member even in long-time cutting of a work material such as free-cutting steel. As a result of diligent research on a DLC film, the following findings were obtained.
First, the basic film structure of the wear-resistant tool member is composed of a TiN hard film formed on a tool base (for example, a tungsten carbide-based cemented carbide), an Al-containing DLC film formed thereon, and further thereon. When the formed Al ₂ O ₃ film was used, the heat-resistant temperature of the Al-containing DLC film was around 500 to 550 ° C., and thus some degree of durability (wear resistance) was exhibited even against heat loads. For example, when this is used for long-time cutting of free-cutting steel, there is a problem that not only the wear resistance is insufficient due to the high heat load during cutting, but also a hard film is likely to be broken. Occurred.

Then, the present inventors further studied, and in the film structure composed of the above-mentioned tool base / TiN hard film / Al-containing DLC film / Al ₂ O ₃ film, the Al content ratio in the Al-containing DLC film and Al By adjusting the composition distribution of the Al component in the contained DLC film, it has excellent heat resistance, durability, and wear resistance, and even when used for long-time cutting of free-cutting steel, the high heat load It has been found that a wear-resistant tool member that can withstand and exhibit sufficient wear resistance can be obtained.

This invention has been made based on the above findings,
“(1) A TiN hard film having a film thickness of 0.5 to 5 μm, an Al-containing diamond-like carbon film having a film thickness of 0.2 to 2 μm, and a film thickness of 0.2 to 2 μm in order from the tool substrate surface side on the tool substrate. In the wear-resistant tool member formed with the Al ₂ O ₃ film,
The Al content in the Al-containing diamond-like carbon film is 5 to 30 atomic%, and the Al content in the Al-containing diamond-like carbon film is from the TiN hard film side to the Al ₂ O ₃ film side. A wear-resistant tool member excellent in lubricity, characterized by having a graded composition that gradually increases according to the above.
(2) The Al content in the Al-containing diamond-like carbon film was 5 to 15 atomic% at the interface with the TiN hard film, and 20 to 30 atomic% at the interface with the Al ₂ O ₃ film. In addition, the wear-resistant tool having excellent lubricity as described in (1) above, which has a gradient composition in which the Al content gradually increases from the TiN hard film side to the Al ₂ O ₃ film side Element. "
It is characterized by.

  Next, the film configuration of the wear-resistant tool member of the present invention will be described.

TiN hard film:
The TiN hard film formed on the surface of the tool base contributes to improving the wear resistance of the wear-resistant tool member due to its own hardness, and at the same time, tight adhesion between the Al-containing DLC film and the tool base (peeling resistance) It has an action as an adhesion film that ensures the property.
The TiN hard film uses, for example, Ti as a sputtering target in the film forming apparatus shown in FIG. 1, and is formed in an Ar—N ₂ mixed gas (for example, Ar flow rate: 40 sccm, N ₂ flow rate: 40 sccm). The film can be formed by sputtering under the condition of 0.1 Pa.
However, if the thickness of the TiN hard film is less than 0.5 μm, the adhesion between the Al-containing DLC film and the tool substrate is not sufficiently ensured. On the other hand, if the film thickness is 5 μm, free cutting steel can be cut for a long time. In addition, since the adhesiveness can be secured stably without causing peeling between the Al-containing DLC film and the tool substrate, the thickness of the TiN hard film is determined to be 0.5 to 5 μm.

Al-containing diamond-like carbon film (Al-containing DLC film):
In the present invention, an Al-containing DLC film is formed on a TiN hard film by sputtering. For example, in the film forming apparatus shown in FIG. 1, metal Al and carbon are used as a sputtering target in an Ar atmosphere (for example, Ar The film can be formed by sputtering under the conditions of a flow rate of 80 sccm, a film forming pressure of 0.1 Pa, and a tool base temperature of 200 ° C.
During film formation, the power of the Al target is adjusted so that the amount of Al contained in the Al-containing DLC film becomes the desired Al content ratio, and along the film thickness direction (that is, from the TiN hard film side to the Al ₂ O An Al-containing DLC film having a graded composition structure in which the Al content rate gradually increases toward the _three film side) is formed.
Preferably, the Al content ratio is 5 to 15 atomic% on the TiN hard film side, the Al content ratio increases toward the Al ₂ O ₃ film side, and the Al content ratio is in the interface region in contact with the Al ₂ O ₃ film. An Al-containing DLC film having an Al concentration gradient composition structure in which is 20 to 30 atomic% is formed.

The characteristics of the Al-containing DLC film are affected by the proportion of Al contained, and the heat resistance improves as the Al content increases, but on the other hand, the adhesion of the underlying film to the TiN hard film tends to decrease. is there.
Specifically, when the Al content of the Al-containing DLC film is less than 5 atomic%, the DLC film has little effect of improving heat resistance due to the inclusion of Al, and in particular, high heat in long-time cutting of free-cutting steel. As a result, it is not possible to exhibit satisfactory heat resistance with respect to the load, resulting in insufficient wear resistance. On the other hand, when the Al content of the Al-containing DLC film exceeds 30 atomic%, Al on the outermost surface Although the adhesiveness with the ₂ O ₃ film is excellent, the adhesiveness with the TiN hard film of the base film is deteriorated and the Al-containing DLC film is likely to be peeled off. Is required to be set at 5 to 30 atomic%.

Furthermore, in the present invention, in order to effectively use the change in characteristics of the DLC film due to the Al content, the graded composition in which the Al content rate gradually increases toward the Al ₂ O ₃ film side along the film thickness direction. An Al-containing DLC film having a structure was formed.
As described above, if the Al content ratio is 5% or more, the effect of improving the heat resistance can be expected, and if the Al content ratio does not greatly exceed 5 to 15%, it adheres to the TiN hard film as the base film. Since the strength can be secured, the Al content in the Al-containing DLC film in the region that forms the interface with the TiN hard film is set to 5 to 15 atomic%, while on the other hand, against high heat load due to long-time cutting of free-cutting steel In order to provide sufficient heat resistance, and to further improve the adhesion with the outermost Al ₂ O ₃ film, the Al content in the Al-containing DLC film in the region forming the interface with the Al ₂ O ₃ film is It is desirable to form an Al-containing DLC film having a gradient composition structure of 20 to 30 atomic%.

The Al-containing DLC film having the above-described gradient composition structure is formed by using metal Al and carbon as a sputtering target in an Ar atmosphere (for example, Ar flow rate: 80 sccm) in the film forming apparatus shown in FIG. By adjusting the power of the Al target under conditions of a pressure of 0.1 Pa and a tool base temperature of 200 ° C., a desired amount of Al is contained, or along the film thickness direction (that is, the TiN hard film side) An Al-containing DLC film having a graded composition structure in which the Al content rate gradually increases from the SiO ₂ film side to the SiO ₂ film side is formed.

  If the film thickness of the Al-containing DLC film is less than 0.2 μm, excellent heat resistance, durability, and wear resistance cannot be exhibited over a long period of use. The film thickness of the Al-containing DLC film is determined to be 0.2 to 2 μm because peeling easily occurs.

Al ₂ O ₃ film:
The Al ₂ O ₃ film formed on the Al-containing DLC film is excellent in heat resistance and wear resistance, and further improves the heat resistance of the Al-containing DLC film under high heat load conditions.
The film formation of the Al ₂ O ₃ film is basically the same as the film formation of the TiN hard film. For example, in the film formation apparatus shown in FIG. 1, the metal Al is used as a sputtering target, and the TiN hard film is formed. With respect to a tool base (shown as a substrate in FIG. 1) on which an Al-containing DLC film is formed, in an Ar—O ₂ atmosphere (Ar flow rate: 40 sccm, O ₂ flow rate: 40 sccm), a film formation pressure of 0.1 Pa, Film formation can be performed by sputtering at room temperature.
However, it is less than the thickness of the _Al 2 _{O 3} film is 0.2 [mu] m, excellent heat resistance possessed by _{the Al} 2 _{O 3} film can not be sufficiently exhibited wear resistance. On the other hand, if the film thickness exceeds 2 [mu] m, The thickness of the Al ₂ O ₃ film was determined to be 0.2 to ₂ μm because peeling and the like are likely to occur.

In the wear-resistant tool member of the present invention, the TiN hard film has wear resistance, the Al ₂ O ₃ film has heat resistance and wear resistance, and the Al-containing DLC film contains 5 to 30 Al. Preferably, the Al-containing DLC film contains 5 to 15 atomic% Al at the interface part with the TiN hard film, 20 to 30 atomic% Al at the interface part with the Al ₂ O ₃ film, Because Al has a gradient composition in the Al-containing DLC film, the Al-containing DLC film has excellent adhesion strength to both the TiN hard film and the Al ₂ O ₃ film and has excellent heat resistance. When this wear-resistant tool member is used as a member for a cutting tool that requires a high heat load such as long-time cutting of free-cutting steel, for example, excellent heat resistance, durability, Exhibits wear resistance and extends tool life Rukoto is possible.

1 is a schematic view of a sputtering film forming apparatus for forming a TiN hard film, an Al-containing DLC film, and an Al ₂ O ₃ film of the wear-resistant tool member of the present invention.

Next, the wear-resistant tool member of the present invention will be specifically described with reference to examples.
Here, an example of using as an insert for free cutting steel for a long time is shown, but the present invention is not limited to this, and can be applied to various wear-resistant tool members such as end mills and drills. It is.

As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. The mixture is blended for 96 hours by a ball mill, dried by a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact is vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under holding conditions, polished, and finished with a mirror finish on the cutting edge rake surface, both of which are made of WC-based cemented carbide and have an ISO standard / SPGN12308 insert shape A- 1 to A-10 were produced.

(A) Next, the film forming apparatus shown in FIG. 1, that is, a sputtering apparatus provided with a metal Ti target, a metal Al target, and a carbon target as a cathode electrode in the film forming apparatus,
(B) The above-mentioned carbide substrates A-1 to A-10 are ultrasonically washed in acetone and dried and supported and mounted in the apparatus so as to be able to rotate and revolve.
(C) Next, the inside of the apparatus was evacuated and kept at a pressure of 0.01 Pa, and the inside of the apparatus was heated to 300 ° C. with a heater, and then Ar gas was introduced into the apparatus and Ar at a pressure of 0.5 Pa was introduced. In this state, a bias voltage of −800 V was applied to the carbide substrate rotating while rotating on the turntable in this state, and the surface of the carbide substrate was cleaned with Ar gas bombardment for 20 minutes.
(D) Next, in a state where the substrate temperature in the apparatus is 300 ° C., N ₂ and Ar are introduced as reaction gases at a ratio of N ₂ : 40 sccm and Ar: 40 sccm, and a film forming pressure of 0.1 Pa is obtained. A sputtering power with an output of 12 kW (frequency: 40 kHz) is applied to the cathode electrode (evaporation source) of the Ti target, while glow discharge is generated on the carbide substrate under the condition that a bias voltage of −100 V is applied. By forming a TiN hard film having a target film thickness shown in Table 2 on the surface of the cemented carbide substrate,
(E) Next, Ar is introduced as a reactive gas at a rate of 80 sccm in a state where the substrate temperature in the apparatus is 200 ° C., and a film forming pressure of 0.1 Pa is set, and output to a carbon target as a carbon source: Sputtering power of 12 kW (frequency: 40 kHz) is applied to an Al target as an Al source, and the output is within a range of 0.3 to 1.8 kW (frequency: 40 kHz) according to a desired Al content ratio. The target film thickness and target composition shown in Table 2 are applied to the surface of the TiN hard film by applying electric power and generating glow discharge under the condition that a bias voltage of −100 V is applied to the cemented carbide substrate. An Al-containing DLC film of
(F) Next, in a state where the substrate temperature in the apparatus is lowered to room temperature, Ar and O ₂ are introduced as atmospheric gases at a ratio of Ar flow rate: 40 sccm, O ₂ flow rate: 40 sccm, and 0.1 Pa is achieved. Glow discharge is performed under the condition that the film pressure is set and a sputtering power of 12 kW (frequency: 40 kHz) is applied to the cathode electrode (evaporation source) of the Al target, while a bias voltage of −100 V is applied to the carbide substrate. As a result, the Al ₂ O ₃ film having the target film thickness shown in Table 2 is formed on the surface of the cemented carbide substrate.
As mentioned above, this invention insert 1-10 as this invention wear-resistant tool member was manufactured by (a)-(f).

For comparison, a TiN hard film and Al ₂ O ₃ film similar to the insert of the present invention are provided, but an Al-containing DLC film having an Al content ratio of less than 5 atomic% on the TiN hard film side is a comparative example insert. 1 and 6, and the Al ₂ O ₃ film side Al content ratio exceeding 30 atomic% were produced as Comparative Example Inserts 2 and 7.
Further, the same TiN hard film and Al ₂ O ₃ film as the insert of the present invention are provided, and the Al content ratio of the Al-containing DLC film is 5 to 30 atomic%, but the Al content ratio in the film is uniform. A composition having no gradient composition structure was manufactured as Comparative Example Inserts 3, 4, 8, and 9.
Further, a comparative example insert 5 having a TiN hard film similar to the insert of the present invention and an Al-containing DLC film having a graded composition structure but having no Al ₂ O ₃ film formed on the Al-containing DLC film. 10 was manufactured.
Table 3 shows a list of membrane configurations of Comparative Example Inserts 1-10.

About this invention insert 1-10 obtained as a result and comparative example insert 1-10, the result of having measured the Al content rate in the Al content DLC film which comprises this by Auger electron spectroscopy is shown in Tables 2 and 3. Indicated.
Furthermore, when the film thickness of each of the above films was measured using a scanning electron microscope (longitudinal section measurement), all showed an average layer thickness (average value of 5-point measurement) substantially the same as the target layer thickness. It was.

Next, in the state where the present invention inserts 1 to 5 and the comparative example inserts 1 to 5 are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SUM22 round bar,
Cutting speed: 60 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.05 mm / rev. ,
Cutting time: 50 minutes,
Dry continuous cutting test of sulfur free cutting steel under the following conditions (referred to as cutting condition A),
In the state where the present invention inserts 6 to 10 and the comparative example inserts 6 to 10 are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / S45C round bar,
Cutting speed: 50 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.05 mm / rev. ,
Cutting time: 100 minutes,
Dry continuous cutting test of carbon steel under the conditions (referred to as cutting condition B),
Was done.
In any cutting test, the flank wear width of the cutting edge was measured.
The measurement results are shown in Table 4.

From the results shown in Tables 2 to 4, the wear-resistant tool member of the present invention is such that the TiN hard film retains wear resistance, and the Al ₂ O ₃ film retains heat resistance and wear resistance. The film contains 5 to 30 atom% of Al, and preferably the Al-containing DLC film is 5 to 15 atom% Al at the interface with the TiN hard film and 20 to 30 atoms at the interface with the Al ₂ O ₃ film. In addition, since Al has a gradient composition in the Al-containing DLC film, the Al-containing DLC film has excellent adhesion strength to both the TiN hard film and the Al ₂ O ₃ film, It has excellent heat resistance. As a result, even when the wear-resistant tool member of the present invention is used as a member for a cutting tool that requires a high heat load such as long-time cutting of free-cutting steel, it can be used over a long period of time. Excellent heat resistance, durability, wear resistance It can be seen that the exhibit.
On the other hand, the tool members of the comparative examples (comparative inserts 1 to 10) are inferior in wear resistance, and the coating peels off or cannot withstand long-time cutting. Obviously, it cannot be said that the tool member has satisfactory characteristics.

  As described above, the wear-resistant tool member of the present invention has excellent heat resistance, durability and excellent wear resistance, and is a cutting tool for long-time cutting of free-cutting steel subjected to high heat load. In addition to being suitable as a member for use, it can be applied as a wear-resistant member in various fields where heat resistance, durability and wear resistance are required.

Claims (2)

A TiN hard film with a film thickness of 0.5 to 5 μm, an Al-containing diamond-like carbon film with a film thickness of 0.2 to ₂ μm, and an Al ₂ O film with a film thickness of 0.2 to ₂ μm in order from the tool substrate surface side. _{In the} wear-resistant tool member formed with _three films,
The Al content in the Al-containing diamond-like carbon film is 5 to 30 atomic%, and the Al content in the Al-containing diamond-like carbon film is from the TiN hard film side to the Al ₂ O ₃ film side. A wear-resistant tool member excellent in lubricity, characterized by having a graded composition that gradually increases according to the above. The Al content in the Al-containing diamond-like carbon film is 5 to 15 atomic% at the interface with the TiN hard film, 20 to 30 atomic% at the interface with the Al ₂ O ₃ film, and _{2. The} wear-resistant tool member having excellent lubricity according to claim 1, wherein the wear-resistant tool member has a gradient composition in which the Al content gradually increases from the TiN hard film side toward the Al ₂ O ₃ film side.

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