JPH04308075A - hard material body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard material suitable for use, for example, as a material for cutting tools, and particularly to a hard material having a thin film of high hardness formed on the surface of the base material.

0002

2. Description of the Related Art A typical example of this type of hard material is one in which a crystalline aluminum oxide thin film is formed on the surface of a base material such as metal or ceramics. In this case, a crystalline aluminum oxide thin film may be formed directly on the surface of the base material, but another thin film (e.g. titanium thin film, titanium nitride thin film, titanium carbide thin film, etc.) is formed as an intermediate layer between them. Sometimes I do.

0003

[Problems to be Solved by the Invention] Incidentally, since the crystalline aluminum oxide thin film has a relatively large crystal grain size, its surface is rough (center line average roughness Ra is 0.3).
micrometers), therefore, when a hard material with such a crystalline aluminum oxide thin film formed on its surface is used as a cutting tool, it is not necessarily possible to obtain sufficiently satisfactory cutting performance and durability. There wasn't.

[0004] In addition, crystalline aluminum oxide thin films have coarse crystal grains, which may result in missing particles, or grain boundaries may occur between the crystal grains, causing fractures or internal defects originating from the grain boundaries. There was a problem that it was easy to use.

Furthermore, although crystalline aluminum oxide thin films are generally formed by thermal CVD, crystalline aluminum oxide thin films have a slow film growth rate (approximately 2 to 3 angstroms/second), so it is difficult to increase the film thickness. However, the film forming process takes a long time. In addition, thermal CV
When using the D method, the film formation temperature is as high as 1000°C or higher, so the base material must of course be limited to heat-resistant materials that can withstand such high temperatures, and reheat treatment may be required after film formation. , the base material may be thermally deformed, or even
During the film formation process, interdiffusion occurs at the boundary between the base material and the crystalline aluminum oxide thin film (or the boundary between the intermediate layer and the crystalline aluminum oxide thin film if an intermediate layer is provided), and as a result, at the boundary between them, There was also the problem that embrittlement occurred and the thin film was likely to peel off.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hard material body suitable for use as, for example, a cutting tool.

[0007]

[Means for Solving the Problems] The hard material body of the present invention is characterized in that it is formed by forming an amorphous aluminum oxide thin film from a gas phase on the surface of a base material made of metal or ceramics. In this case, another thin film may be formed in a single layer or in multiple layers as an intermediate layer between the base material and the amorphous aluminum oxide thin film.

[0008]

[Function] Because the thin film made of amorphous aluminum oxide is non-crystalline, its surface is extremely smooth compared to the crystalline aluminum oxide thin film that has been commonly used. Since no noticeable grain boundaries are generated, defects within the film are less likely to occur, and therefore, when applied to cutting tools, wear resistance is improved and excellent cutting performance and durability can be obtained. Furthermore, amorphous aluminum oxide thin films can be formed at relatively low temperatures and at high speeds by ion plating.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the structure of a hard material body according to an embodiment of the present invention, in which reference numeral 1 represents a base material made of metal or ceramics, and 2 represents a thin film formed on the surface of the base material. The thin film 2 is made of amorphous or non-crystalline aluminum oxide. The thickness of this amorphous aluminum oxide thin film 2 may be set appropriately, but when this hard material body is used as a cutting tool, it is preferably about 0.1 to 20 μm, preferably about 0.2 to 10 μm. In addition, in the case shown in FIG. 1, the amorphous aluminum oxide thin film 2 is formed directly on the surface of the base material, but in the case shown in FIG.
As shown in FIG. 2, another thin film 3 may be appropriately formed as an intermediate layer between them.

The above amorphous aluminum oxide thin film 2 can be formed, for example, by a high frequency excitation type ion plating apparatus as shown in FIG. 3 or an arc discharge type ion plating apparatus as shown in FIG.

The high frequency excitation type ion plating apparatus shown in FIG. 3 introduces a reactive gas G such as argon gas and oxygen gas into a vacuum chamber 5 from a gas introduction pipe 6 to maintain the inside of the vacuum chamber 5 at a predetermined pressure, for example 1 to 9. ×10
The evaporated material M (
Aluminum or aluminum oxide) is melted and evaporated by an electron gun 9, and the evaporated evaporation material M and reaction gas G are heated to
High frequency coil 11 to which a high frequency of 3.56 MHz is applied
The positive ions are ionized positively by the heater 1 while a negative voltage is applied by the DC power supply 12.
3, the base material 1 is heated by the base material 1.

Furthermore, the arc discharge type ion plating apparatus shown in FIG.
6 to positively ionize the evaporation material M and the reaction gas G, and the other configurations are the same as the high frequency excitation type ion plating apparatus.

[0013] In both cases of using the high frequency excitation type ion plating apparatus and the case of using the arc discharge type ion plating apparatus, the temperature of the base material 1 is kept at a relatively low temperature of about 20 to 800°C, preferably about 200 to 450°C. It is necessary to set it to . This is because if the temperature of the base material 1 is higher than that, the formed thin film 2 may crystallize and become a crystalline aluminum oxide thin film. Also,
When forming another thin film 3 as an intermediate layer between the base material 1 and the thin film 2, the thin film 3 is formed on the surface of the base material 1 in advance, and the surface of the thin film 3 is coated as described above. Then, the amorphous aluminum oxide thin film 2 may be formed.

Since the amorphous aluminum oxide thin film 2 formed on the surface of the base material 1 as described above is non-crystalline, its surface is extremely thin compared to the crystalline aluminum oxide thin film that has conventionally been generally employed. It's smooth. That is, as mentioned above, the conventional crystalline aluminum oxide thin film has coarse crystal grains and its center line average roughness Ra is 0.
．． On the other hand, the amorphous aluminum oxide thin film 2 has a center line average roughness Ra of about 0.02 to 3 μm.
The thickness is approximately 0.04 μm, which is sufficiently smooth. Moreover, since the amorphous aluminum oxide thin film 2 is non-crystalline and no noticeable grain boundaries occur, defects are unlikely to occur inside the film. Therefore, when this hard material is applied to cutting tools, This reduces the frictional resistance that occurs between the material and the workpiece during cutting, resulting in improved wear resistance compared to conventional products, as shown in the results of the wear resistance test described below. It provides excellent cutting performance and durability.

Furthermore, since the amorphous aluminum oxide thin film 2 can be formed at a relatively low temperature by the ion plating method, the conventional crystalline aluminum oxide thin film can be formed by thermal CVD.
The heat resistance required for the base material 1 is reduced compared to the case where the film is formed by the D method, so the range of application of the base material is expanded, and heat treatment after film formation is not required. Thermal deformation is suppressed, and the thin film 2 and base material 1 are separated during film formation.
Alternatively, interdiffusion with another thin film 3, which is an intermediate layer, becomes difficult to occur, and embrittlement does not occur at the interface between them, and as a result, peeling of the thin film 2 becomes difficult to occur.

Furthermore, when forming the amorphous aluminum oxide thin film 2 by the ion plating method, 3
A film deposition rate of about 0 to 50 angstroms/second can be obtained, which is much faster than when depositing a crystalline aluminum oxide thin film by thermal CVD, and as a result, Productivity is greatly improved and product costs can be reduced.

Tests conducted to demonstrate the wear resistance of the hard material of the present invention and their results will be described below.

(Test Example 1) The following three samples A and B
, C were prepared, and after cutting was performed under the following cutting conditions, the flank wear amount of each was measured. The measurement results are shown in FIG. Sample A (product of the present invention): Throwaway chip with an amorphous aluminum oxide thin film formed on the surface of the base material. Sample B (conventional product): Throw-away chip with a thin titanium nitride film formed on the surface of the base material by thermal CVD. Sample C (conventional product): Throw-away chip with a crystalline aluminum oxide thin film formed on the surface of the base material by thermal CVD. Cutting conditions: Work material S45C, cutting speed 200 m/min, feed 0.25 mm/rev. , depth of cut 0.5 mm, cutting time 30 minutes (3 measurements taken every 10 minutes).
From the test results shown in FIG. 5, it was confirmed that Sample A, which is a product of the present invention, had a smaller amount of flank wear than Samples B and C, which are conventional products, and had excellent durability.

(Test Example 2) Sample A same as Test Example 1
, B, and C, and a similar test was conducted by changing only the cutting conditions as follows. The results are shown in FIG. Cutting conditions: Work material S45C, cutting speed 250 m/min, feed 0.
46mm/rev. , depth of cut 1.5mm, cutting time 6
minutes (take two measurements every 3 minutes). In this case as well, from the test results shown in Figure 6, Sample A, which is a product of the present invention, has a smaller flank wear amount than Samples B and C, which are conventional products, and is superior in durability. was confirmed.

In the above example, the hard material of the present invention was applied to a cutting tool, but the amorphous aluminum oxide thin film not only has high hardness but also has excellent electrical insulation and heat resistance. Moreover, this thin film itself also has the property of being transparent. Therefore, the hard material of the present invention can be used not only as a cutting tool, but also as a variety of other uses by utilizing the above-mentioned properties, such as mechanical parts that require wear resistance, electrical insulation materials, and decorative items. Can be applied.

[0021]

[Effects of the Invention] As explained in detail above, the hard material of the present invention is formed by forming an amorphous aluminum oxide thin film on the surface of a base material made of metal or ceramics, so it is non-crystalline. Because of this, it has an extremely smooth surface and has excellent wear resistance due to the amorphous aluminum oxide thin film that does not easily cause defects inside the film. Therefore, it has excellent cutting performance and durability especially when used as a cutting tool. can be obtained. Furthermore, since amorphous aluminum oxide thin films can be formed at relatively low temperatures and at high speeds, they have the advantage of reducing the heat resistance of the base material, widening the range of application, and improving productivity.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing the structure of a hard material body that is an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing the structure of a hard material body according to another embodiment of the present invention.

FIG. 3 is a diagram showing an example of an ion plating apparatus for manufacturing the hard material body of the present invention.

FIG. 4 is a diagram showing another example of the ion plating apparatus for manufacturing the hard material body of the present invention.

FIG. 5 is a diagram showing the results of a wear resistance test for products of the present invention and conventional products.

FIG. 6 is a diagram showing the results of a wear resistance test for products of the present invention and conventional products.

[Explanation of symbols]

1 Base material 2 Amorphous aluminum oxide thin film 3 Thin film (
middle class).

Claims (2)

[Claims] 1. A hard material body characterized by forming an amorphous aluminum oxide thin film from a gas phase on the surface of a base material made of metal or ceramics. 2. The hard material body according to claim 1, wherein another thin film is formed as an intermediate layer between the base material and the amorphous aluminum oxide thin film in a single layer or in multiple layers.