JPH0782082A - Part coated with ultra-hard film and its production - Google Patents

Abstract

PURPOSE:To provide a part coated with an ultra-hard film composed of an ultra-hard film such as diamond firmly bonded to a thermet substrate and to provide a process for the production of the coated part. CONSTITUTION:The surface of a thermet substrate is treated in an atmosphere, solution or molten liquid containing the group Ia or Vb element or its compound and an ultra-hard film is formed on the treated surface of the substrate by vapor-phase synthesis. The ultra-hard film formed by this process has high bonding strength to the substrate, is polishable to a surface roughness of <=0.1mumRmax, has a thick residual film to endure severe cutting work and is suitable as a cutting tool material having high accuracy and long life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting and abrasion resistant tool, an abrasion resistant component, an optical component, an ultra hard film coated member used as an electronic material, and a method for producing the same.

[0002]

2. Description of the Related Art When a diamond is coated on a cemented carbide by a vapor phase synthesis method, amorphous carbon is likely to be produced on cobalt as a binder phase, which hinders the nucleation of diamond.
As a solution, it is disclosed that by removing cobalt at a constant depth from the surface of the base material by etching treatment with an acid, a diamond film can be formed and that the adhesion strength between the diamond film and the base material can be improved. As typical examples thereof, Japanese Patent Publication No. 63-20911 and Japanese Patent Laid-Open No. 62-67174.
There is a gazette.

Further, Japanese Patent Laid-Open No. 63-100182 discloses that a cemented carbide containing 1 to 4% by weight of cobalt serving as a binder phase is suitable as a diamond-coated substrate. Even in the case of cobalt cemented carbide, it is essential to remove cobalt by acid etching.
In addition to the acid method, a method of dry etching in a fluorocarbon plasma and a method of sputter etching with hydrogen, argon gas, etc. are also available as methods for removing the binder phase.
No. 62-67174.

On the other hand, a method of forming an intermediate layer has been proposed as a method of increasing the adhesion strength without removing the binder phase as described above. As an example, a layer made of carbides, nitrides, borides, etc. of IVa, Va, and VIa group elements or their compounds or mixtures is formed on the surface of a base material such as cemented carbide, and a diamond film is formed on the layer. JP-A-58-126972, JP-A-59-182300 and JP-A-63-1280 are available.

Further, in forming a diamond film on the surface of a substrate such as cemented carbide by a vapor phase synthesis method, B such as B ₂ H ₆ is present during the vapor phase synthesis so that B is formed in the formed diamond film. Japanese Patent Laid-Open No. 163275/1986, similarly, after forming an intermediate layer of B and / or a boron compound and diamond and / or diamond-like carbon by a vapor phase synthesis method similarly in the presence of B ₂ H _{6 and the} like, Japanese Unexamined Patent Publication No. 62-133067 for forming a diamond film can also be seen.

Separately, it is proposed to improve the adhesion strength to a diamond film by plasma-treating the surface of a base material such as cemented carbide in the presence of a volatile boron compound such as B ₂ H _6.
There is 101167 publication. In this proposal, although the cause of the improvement in adhesion by the plasma treatment is not clear, the cobalt contained in the base material may be converted to a boron compound, or
It is presumed that it is because the film of is formed,
Is described. Further, the film thickness of the ultra-hard film is as described in JP-A-62-4
No. 7480 is characterized by a thickness of 0.1 to 20 .mu.m, and JP-A No. 1-242401 describes that the thickness of 20 .mu.m is not preferable because the film peels off due to thermal stress in the film.

[0007]

As described above, many proposals have been made for improving the adhesion strength of diamond films, but a method having sufficient quality and suitable for industrial production has not yet been found. First, the establishment is required.
That is, after the acid etching treatment, the adhesion of the superhard film coated on the cemented carbide is not always sufficient, the application as a cutting tool, Al-12wt% Si or less alloy, graphite, carbon fiber reinforced plastic, It is limited to non-sintered ceramic compacts, etc., and cannot withstand intermittent cutting of alloys of Al-18wt% Si or more and heavy cutting such as high feed and deep cutting for a long time. Furthermore, the thickness of the coating film on the cemented carbide that has been etched with acid can only be 0.1 to 5 μm as a measure against peeling, so even if peeling of the diamond film does not occur, the flank wear (Vb) amount for judging the tool life is The base material is exposed before reaching the predetermined amount, which naturally limits the tool life.

On the other hand, the method of providing the intermediate layer has a problem that the manufacturing process is complicated, and it is hard to say that the adhesive force between the intermediate layer and the diamond film has reached a practical level. Further, the plasma treatment method in the presence of a volatile boron compound requires a special device considering safety because it is a toxic gas, and the adhesion force between the substrate and the diamond film is sufficient to withstand cutting. It is hard to say that it has strength. INDUSTRIAL APPLICABILITY The present invention stably provides an ultra-hard film-coated member having high adhesion without using a special device, and by coating a thick film, an ultra-hard film-coated member having a longer life and its production. A method is provided to solve the above problems.

[0009]

[Means for Solving the Problems] In solving the problems, the inventors did not adopt the conventional methods of etching / removing the binder phase and forming an intermediate layer, and did not use an atmosphere such as plasma treatment in a volatile boron compound. As a result of repeated exploratory research on a method of coating a cermet with an ultra-hard film regardless of the high-temperature treatment, it was possible to identify a method suitable for industrial production with uniform quality. That is, the surface of the cermet substrate is heat-treated in an atmosphere containing at least one Vb group element such as N or a compound thereof, or immersed in a solution or melt of at least one Ia or Vb group element or a compound thereof. When an ultra-hard film made of diamond and / or diamond-like carbon is formed on the treated surface by a vapor phase synthesis method, the adhesion strength of the ultra-hard film is remarkably improved, and the ultra-hard film having a thickness of 20 μm or more It was confirmed that the film can be coated and that the film-forming surface can be polished, and that the polishing performance can be further improved by polishing. This confirmation was carried out by a cutting test of A390 (Al-18 wt% Si), and the contents will be described in detail in the following examples.

In each of the examples, a base material made of cemented carbide represented by WC--Co is shown in comparison with the prior art, but it is made of titanium carbonitride and a binder phase metal. It goes without saying that the present invention can also be applied to those using cermet as a base material. In addition, it is of course possible to add a known or new process such as a scratching treatment to the surface of the base material before the treatment in the process shown in the examples.

[0011]

【Example】

(Example 1) 1. Base material WC-6% Co cemented carbide chip 2. Nitriding treatment (N ₂ + Ar) The substrate was loaded into a microwave plasma CVD apparatus, and both gases were kept inside the apparatus at a pressure of 25 Torr so that N ₂ and Ar gases were kept in a 1/2 volume atmosphere. While being supplied, heat treatment is performed at 800 ° C for 2 hours to nitride the substrate surface.

3. Film formation After the above treatment, the supply gas was changed to form a film on the surface of the substrate in the same apparatus. Film formation conditions are pressure 100 Torr, gas composition
H ₂ -2% CH ₄ , substrate temperature 900 ° C, film formation time 10 hours (approximately 1
It was possible to obtain a diamond film having a thickness of 15 μm.

4. Finishing processing The flank and rake surface of the chip on which the above-mentioned film was formed were polished to finish the cutting edge. The film thickness after polishing was 10 μm.

5. Cutting Test A cutting test was performed on the film-formed chips with and without finishing, and as a comparative example, commercially available diamond film-coated carbide chips (film thickness 5 μm, unfinished). The cutting conditions are as follows, and the test results show that the flank wear is small and the cutting life is significantly extended as shown in FIG. Cutting equipment Mori Seiki lathe SL-15 type Work material A390 (Al-18wt% Si alloy) Cutting speed 800m / min Cutting depth 0.5mm Feed 0.1mm / rev Cutting method Wet continuous cutting (water-soluble emulsion)

The above-mentioned nitriding treatment conditions are as follows: the atmosphere is N ₂ 1%, 10
% H ₂ 90-99%, temperature 600 ℃, 1000 ℃, holding time 0.5
When the time was changed to 1 hour and 5 hours, the operation was carried out for each of them, and the film was applied to the implemented product, and it was satisfactory.

Further, when a test was carried out with N ₂ in the atmosphere replaced with NH ₃ , PH ₃ and AsH ₃ which also contained a Vb group element, the film formation was able to proceed. This is because when the base material is heat-treated in an atmosphere containing a Vb group element, the Vb group element permeates or penetrates into the bond metal phase of the base material surface layer, and the activity of the bond metal during the formation of the diamond film is increased. It is thought to be suppressed.

(Embodiment 2) 1. Base material WC-6% Co cemented carbide 2. Borax treatment (Na ₂ B ₄ O ₇ ) The substrate was immersed in a molten salt having the following composition heated to 950 ° C. for 3 hours. It is considered that the heating temperature is preferably 850 to 1100 ° C. Na ₂ B ₄ O ₇ Na ₂ B ₄ O ₇ + B ₄ C 15% NaBF ₄ + 5% B ₄ C + 80% NaCl

3. Film formation Under the same conditions as in Example 1, a diamond film with good adhesion was obtained.

(Example 3) 1. Base material WC-6% Co cemented carbide 2. Borax electrolysis treatment (Na ₂ B ₄ O ₇ ) A base material was immersed in a molten salt having the following composition heated to 950 ° C. for 3 hours, and the base material was used as a cathode and platinum was used as an anode.
A current of A / cm ² was passed to electrolyze for 1 hour. Heating temperature is 8
The temperature is preferably 50 to 1100 ° C, and the anode may be replaced with graphite. Na ₂ B ₄ O ₇ Na ₂ B ₄ O ₇ + NaCl + B ₂ O ₃ HBO ₂ + NaF

Since molten borax has a high viscosity, 850 ° C.
Since it is difficult to process, the temperature is higher than this. Also,
In electrolysis, the back side of the cathode facing the anode is shaded and the process is difficult to proceed. Therefore, use a plurality of anodes or rotate the substrate.

3. Film formation Under the same conditions as in Example 1, a diamond film with good adhesion was obtained. A film formed on a substrate electrolyzed in a molten salt of Na ₂ B ₄ O ₇ but having a thickness of 10 several μm from the diamond film surface in the depth direction.
The SIMS profile up to m is shown in FIG. Co has a low concentration and Na and B have a high concentration on the surface of the base material. Na and B are contained inside the base material, and this is W
It is considered that they contribute to the film formation in the form of a compound such as —Na—B—C.

(Embodiment 4) 1. Base material WC-6% Co cemented carbide chip 2. Sodium hydroxide treatment (NaOH) A solution containing NaOH at a concentration of 1, 3 or 5N is placed in an alumina container, and the base material is placed therein. At this time, the temperature of the solution was three kinds of 25 ° C., 50 ° C., and 90 ° C. for each standard solution, and each of them was immersed for 1 hour and washed with water. 3. The treated base material of the film formation 2 is charged into the hot filament CVD apparatus, the pressure is 100 Torr, the gas composition is H ₂ -1% CH ₄ , the base material temperature is 900 ° C.
Thus, film-forming products with film-forming times of 240 minutes and 600 minutes were obtained.

FIG. 3 shows a SIMS of the substrate from the diamond surface to a depth of several tens of μm in the depth direction, which was obtained by immersing the substrate in 50 ° C. NaOH and 3N solution for 1 hour and then forming a film for 240 minutes.
3 shows a depth profile according to FIG. From Fig. 3, the base material surface has a low concentration of Co and, on the contrary, a high concentration of Na.
It can be seen that Na penetrates to the inside of the base material. It is considered that Co-Na is precipitated by the dipping treatment and that a W-Na-C compound is generated, and it is considered that these reactions contribute to the film formation of diamond.

Before the dipping treatment, the surface of the substrate is 3.0 μm.
The effects on the film formation of the ground surface of about Rmax and the lapping surface of about 0.2 μmRmax were examined, and the ground surface showed good adhesive force and was effective. The surface of the lapped base material has a small adhesive force, and it is necessary to make the surface roughness to a certain level or more by a scratching process or the like.

(Embodiment 5) Only the sodium hydroxide treatment of Embodiment 2 No. 2 was changed to the following. The substrate was immersed in an aqueous potassium hydroxide solution (KOH) and treated at 50 ° C for 30 minutes. As a result, it was possible to obtain a film having substantially the same thickness as in Example 4.

(Example 6) Only the sodium hydroxide treatment of 2 of Example 4 was changed as follows. Immerse the base material in an aqueous solution of sodium chloride (NaCl) 1 and water 2
It was treated at 30 ° C. for 30 minutes. As a result, it was possible to obtain a film formation state that was substantially the same as in Example 4.

FIG. 4 shows a conventional commercial product and an example product (Example 4).
FIG. 3 is a diagram showing a comparison of the cutting performance with the film-formed product shown in FIG. 3), and shows the surface roughness of the workpiece by cutting. In the drawing, the cutting conditions are as follows, based on the cutting test results of the film-forming product of the present invention used as the cutting blade and the one used after polishing. Cutting equipment Mori Seiki lathe SL-15 type Work material A390 (Al-18wt% Si alloy) Cutting speed 800m / min Cutting depth 0.5mm Feed 0.1mm / rev Cutting method Wet continuous cutting (water-soluble emulsion)

The polishing of the product of the present invention is carried out by conventional skiff polishing or diamond wheel polishing.
It was possible to finish the surface roughness to mRmax or less. It has been confirmed that the mechanical polishing enables high-precision processing, which indicates the high adhesion strength of the ultra-hard film, and the one capable of this can exhibit sufficient cutting performance. Of course, this is one method of evaluation, so in the practice of the present invention,
As a method for finishing the surface of an ultra-hard film when forming a cutting edge, there is no need for mechanical polishing, but laser processing, ion processing, addition of ultrasonic waves, high energy, or other known or new processing method. It goes without saying that you may adopt it.

Substrates treated according to the present invention are: Ia, Vb
Substrates treated with one or more of the group elements or compounds thereof, when worn by using a super-hard film coated on the surface, or by mechanical, high energy processing,
After removing the film, the ultra-hard film can be coated again. When the ultra-hard film is formed again, the re-treatment can be omitted. It is speculated that this is because the elements used for the treatment are present even inside the substrate as shown in FIGS.

[0030]

According to the present invention, the surface of the base material forming the ultra-hard film is preliminarily treated in the presence of at least one of the elements Ia and Vb, and the ultra-hard film is coated to a thickness of about 20 μm or more. And has an adhesive strength capable of mechanically polishing the film surface,
Since the film thickness after polishing is also 5 μm or more, it is possible to perform highly accurate and long-life cutting of difficult-to-cut materials such as high Si—Al alloys.

In addition, the production of the Ia and Vb group elements is performed by treating the apparatus used for film formation in the atmosphere in which the apparatus is used, or by immersing it in a solution or a melt at a relatively low temperature. The operation is low cost, safe and easy, and suitable for industrial production.

[Brief description of drawings]

FIG. 1 is a view showing a cutting test result of Example 1 and a comparative example.

FIG. 2 is a diagram showing a SIMS depth profile from a substrate surface to a depth of several tens of μm in Example 3.

FIG. 3 is a diagram showing a SIMS depth profile up to several tens of μm from the substrate surface in Example 4.

FIG. 4 is a diagram showing cutting test results of Example 4 and a comparative example.

[Explanation of symbols]

A: Test results of the flank and rake surface of the example polished. B Test results of the as-deposited film in Example. C Test results of comparative example (conventional as-formed film).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C23C 16/26 // B23B 27/14 A 9326-3C (72) Inventor Nariyoshi Kawai Sakai Osaka Prefecture 2-chome, Hobokucho, Ichi, Osaka Inside Diamond Diamond Co., Ltd.

Claims (3)

[Claims] 1. An ultra-hard film made of diamond and / or diamond-like carbon is formed on the surface of a cermet substrate which has been previously treated with one or more elements of group Ia or Vb or a compound thereof, by a vapor phase synthesis method. An ultra-hard film-coated member characterized by the following. 2. A cermet substrate is heat-treated in an atmosphere in which one or more Vb group elements or compounds thereof are present, and then a diamond and / or diamond-like film is formed on the surface of the substrate by a vapor phase synthesis method. A method for manufacturing a super-hard film-coated member characterized by the above. 3. A cermet base material comprising a group Ia or Vb element
A superhard film-coated member characterized by forming a diamond and / or a diamond-like carbon film on the surface of the base material by a gas phase synthesis method after immersion treatment in a solution or heating melt containing one or more kinds or compounds thereof. Manufacturing method.