JPH01212766A - Hard polycrystalline diamond tool - Google Patents

Abstract

PURPOSE:To produce a diamond tool having superior strength and heat resistance by brazing polycrystalline diamond synthesized by a low pressure vapor phase method to a support member made of a metal with an alloy brazing filler metal having a specified m.p. CONSTITUTION:Polycrystalline diamond made practically of diamond and having 0.1-3.0mm thickness is synthesized by a low pressure vapor phase method and brazed to a support member with an alloy brazing filler metal having 700-1,300 deg.C m.p. An alloy for high temp. brazing contg. one or more among Au, Ag, Cu, Ti and Ta is used as the brazing filler metal, the thickness is regulated to 0.1-100mum and the support member is made of steel or a sintered carbide alloy. A diamond tool having superior heat resistance is obtd. without reducing strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diamond tool suitable for use as a cutting tool, a wear-resistant tool, or the like.

[Prior art] Diamond sintered bodies made by gimming fine diamond powder under ultra-high pressure have already been used as tools for cutting non-ferrous metals.
Widely used for drill bits and wire drawing dies.

For example, Japanese Patent Publication No. 52-12126 discloses a method for producing this type of sintered body, in which diamond powder is placed in contact with a molded or sintered body of We-Co hard alloy, Sintering is carried out at a temperature above the temperature at which the liquid phase of the cemented carbide occurs and under ultra-high pressure. At this time, some of the CO in the cemented carbide penetrates into the diamond powder layer,
Acts as a binding metal. Diamond sintered bodies made by the method disclosed in this prior art contain about 10 to 15 parts by volume of CO.

The deconsolidation described above has sufficient practical performance as a cutting tool for non-ferrous metals and the like. However, there were 9 drawbacks such as poor heat resistance. For example, when this sintered body is heated to a temperature of 750° C. or higher, a decrease in wear resistance and strength is observed, and furthermore, at a temperature of 900° C. or higher, the sintered body breaks. This is thought to be due to the graphitization of diamond occurring at the interface between the diamond particles and CO, which is a binder, and thermal stress due to the difference in thermal expansion coefficients during heating of the two.

Furthermore, it is known that when a sintered body using Co as a binder is treated with an acid to remove most of the binding metal layer, the heat resistance of the sintered body is improved.

For example, JP-A-53-1) 4589 discloses a method for producing a diamond sintered body with improved heat resistance. However, in this prior art, the removed portions of the bonded metal phase become pores, so although the heat resistance is improved, there is a problem in that the strength is reduced.

On the other hand, attempts have been made to sinter only diamond powder under ultra-high pressure, but since the diamond particles themselves are difficult to deform, pressure is not transmitted to the gaps between the particles, resulting in graphitization and diamond powder. Only graphite composites have been obtained.

Furthermore, tools coated with a thin film of polycrystalline material consisting only of diamond are known, but this type of tool has a thin film and insufficient adhesion strength to the substrate, so it is difficult to obtain sufficient performance. It has not been done.

The object of the present invention is to provide a diamond tool with high strength, wear resistance, and heat resistance, which solves the problems of the conventional tools described above.

[Failure to solve the problem]

In the present invention, polycrystalline diamond synthesized by a low-pressure gas phase method and consisting essentially of diamond has a melting point of 700 to 700.
The present invention relates to a hard polycrystalline diamond tool, characterized in that it is brazed to a support member made of metal and/or alloy using an alloy brazing filler metal at 1300°C.

The thickness of the polycrystalline diamond in the present invention is preferably within the range of 1) to 50-50. Also, the thickness of the brazing material is 0.1 to 1
It is preferable that it is within the range of 00 μm. The alloy brazing material of the present invention is Au.

A cryogenic brazing alloy containing 1M1 or more of Ag, Ou, Ti, and Ta is preferable, and steel or a sintered carbide alloy is preferable as the supporting member.

The polycrystalline diamond tool of the present invention has significantly improved heat resistance compared to conventional sintered diamond tools, and has a heat resistance of about 1300
It has been found that it can withstand heating at temperatures of .

It also has high strength and wear resistance.

[Effect]

The polycrystalline diamond tool of the present invention will be explained below by showing its manufacturing method.

In the present invention, polycrystalline diamond is synthesized by a method in which diamond is precipitated from a gas phase under low pressure conditions where diamond is thermodynamically metastable. This low-pressure gas phase method consists of 1) chemical distillation method (
avn method), 2) plasma OVD method, and 3) ion beam evaporation method, and a desired method can be selected and implemented.

Using these low-pressure gas phase methods, CL1 to 50■
A polycrystalline body consisting essentially of diamond with a thickness of . Here, the thickness tl-(L1■ or more) is
This is because when actually used as a cutting tool, the flank wear width during the tool life is often 1)- or more. Moreover, the thickness of 10 m or less indicates the thickness of a commonly used tool, and is not particularly limited as it directly affects its performance. Furthermore, if wear resistance is particularly required, the thickness may be set to α5- to 50-. This is thought to be because the thicker the polycrystalline body, the better its heat dissipation properties, which prevents the temperature of the cutting edge from increasing during use of the tool. The thickness of a commonly used polycrystalline body is generally approximately α5~i, Om.

The material of the substrate on which the polycrystalline material is deposited is preferably one whose coefficient of thermal expansion is close to that of diamond, taking into consideration the relaxation of internal stress that occurs during the preparation of the polycrystalline material, such as Mo. , W, Si, H10, MutH, B, O, and the like.

Next, the substrate on which the polycrystalline diamond has been deposited is removed mechanically or chemically to form a polycrystalline body containing only diamond, and this polycrystalline body is brazed to a support member. Using an alloy brazing material with a melting point of 700 to 1300°C,
A diamond polycrystal and a support member made of metal and/or alloy are joined. The reason why the melting point of the brazing filler metal used is limited to the above range is that if a filler metal with a melting point of less than 700°C is used, the bonding strength between the polycrystalline body and the support member will be low9, and the cutting edge during tool manufacturing is a work process. It is also undesirable because peeling occurs at the braze-resistant part when using tools. Also, 1300'C
It is not preferable to use a brazing filler metal with a high melting point exceeding 100% because it converts polycrystalline diamond into graphite during brazing, resulting in a decrease in tool performance.

Therefore, it is preferable to use a brazing filler metal that has as high a bonding strength as possible within the above brazing temperature range, and suitable high-temperature brazing filler metals include, for example, one or more types selected from Au, Ag, Cu, Ti, and Ta. Examples include those containing. The specific columns are shown in the implementation column. In addition, even if these brazing fillers are used, the thickness of the filler filler after brazing surgery may be 1) 1 to 10%.
It is necessary to set the thickness to 0 μm, preferably 50 μm. If it is less than 0.1 μm, brazing tends to be uneven;
On the other hand, if it exceeds 100 .mu.m, this is not preferable as it may lead to a decrease in the strength of the wax section. Brazing can be carried out by high frequency heating in a non-oxidizing atmosphere, heating in vacuum, or the like.

Hardened steel is usually used as the support member, but if particularly rigidity is required, a sintered carbide alloy such as a we gold alloy TIC alloy, a Mono alloy, etc. can be used. Furthermore, it is of course possible to use metals and/or alloys other than these as the supporting member. There is no particular limit to the thickness of the support member, but in order to alleviate thermal stress during brazing, the thickness of the polycrystalline body and the support member may be adjusted depending on the difference in thermal expansion coefficient. It is important to select the appropriate ratio. For example, when W4, which has a coefficient of thermal expansion 5 to 6 times that of diamond, is used as a support member, the thickness of the support member must be made thinner than that of a polycrystalline material, otherwise peeling will easily occur.

The polycrystalline diamond tool of the present invention produced as described above has significantly improved heat resistance that can withstand heating to 1300°C, as shown in the following examples. It is conceivable that there is no binder phase that promotes thermal deterioration. This also gives it nine characteristics that make it superior to conventional sintered diamond in terms of strength.

〔Example" Hereinafter, the present invention will be described in detail based on the implementation series.

Example 1 Polycrystalline diamond with a thickness of 18 mm was synthesized by microwave plasma OVD method using MO as a substrate under the following conditions for 8 hours.

Raw material gas (am): H, 200CC/m1n-O
Ha 4 CC/ min %Ar 100 cc/
min pressure crab 500 torr microwave camera output crab aaow The obtained nine polycrystalline diamond μ grains had a diameter of 3 μm and 8 degrees, and as a result of measurement, the specific gravity was 551, and the identification by i spectroscopic analysis showed that it was from a diamond single phase. It became clear that this would happen.

Next, this bonded diamond and substrate was treated with aqua regia to remove only the substrate. The thus obtained polycrystalline body consisting essentially of diamond was brazed to a WE-CO alloy support using an Ag-Ti alloy 69 material having a thickness of 1).

Brazing was performed by heating to 1000°C for 20 minutes in a vacuum of 2 x 10-' torr.

The thickness of the filter 9 material in the tool was 50 μm.

A cutting tip was produced by grinding the tool material obtained by the above method. For comparison, 10 volumes of CO
Cutting chips were also prepared for sintered diamond containing 1.2% and 2.2 and 4.2 for sintered diamond containing 2.0% of Co2 and 2.2 for extracting Co2 by acid treatment, respectively, and their performance was evaluated. Incidentally, in brazing the sintered diamond (2), since the change to graphite was remarkable under the above conditions, silver solder having a melting point of 700° C. was used and carried out by high-frequency heating in the atmosphere.

The evaluation results are shown in Table 1. In this evaluation, an alumina sintered body with a Guitzkaas hardness of 2000 was used as the rigid material, cutting speed: 30 m/min and 80 m/min s, depth of cut: 2 mm, feed: α025■/rθv1, and cutting length: The test was conducted at a distance of 400 m under wet conditions.

Table 1 As a result, ■ has improved heat resistance compared to ■, so
It is thought that the amount of wear is reduced under the cutting speed condition of 80 m/min, but at 30 wl/min, the cutting resistance (especially thrust force) increases. It is thought that the rake face was chipped in the form of peeling due to insufficient strength under the cutting speed condition of nin. The polycrystalline diamond tool of the present invention is a comparative product ■,
Since the strength, wear resistance, and heat resistance are all improved compared to (2), it is clear that the amount of wear is much smaller regardless of the cutting speed.

Implementation row 2 By the same microwave plasma OVD method as in implementation row 1,
Polycrystalline diamond was synthesized under the conditions shown in Table 2, the substrate was removed by grinding, and a cutting tip was produced after brazing to a support member. For comparison, tools were also fabricated using commercially available sintered diamond containing Co (HN3) and cemented carbide coated with a thin diamond film (K, L). All of the polycrystalline bodies (A-G) according to the present invention were composed of a single diamond phase and exhibited a Guitzkaas hardness of 10,000 to 12,000 Y/2, and this property did not change even after heating during brazing. The cutting performance was compared between these and the tools of Comparative Materials H to -, excluding Comparative Product H, which had a high brazing temperature and a deteriorated sintered body.

Table 3 shows the comparison results. The cutting conditions are A for the rigid material.
Using 4-20% B, cutting speed: 500 m/m
1nx cutting depth; (L4m1), feed: α1 cod/r
ev, cutting time: 50 m1n, and was carried out by dry turning in the longitudinal direction of the outer periphery.

Table 3 Conventional sintered diamonds suffer from severe wear, and thin-film diamond-coated tools suffer from peeling due to the weak adhesion of the coating film, whereas the tool according to the present invention does not suffer from chipping or peeling. It was found to have extremely high wear resistance properties.

Implementation row 3 High frequency plasma Ct'VD method and thermal filament 0'V
Polycrystalline diamond was synthesized by method D.

In the former method, MO was used as the substrate, and after being evacuated, it was heated to 900°C. Then, the molar ratio is OH, :H
, = 1:300 was flowed at 40 cc/min, and the pressure inside the reaction chamber was adjusted to 55 to
I made it rr. Next, a high frequency oscillator applies an output of 850W to induce plasma, and the thickness (L8
− polycrystalline diamond was synthesized.

In the latter method, W is used for the substrate and 950°C is used after evacuation.
heated to ℃. Add 70% of the mixed gas with the same composition as above to this.
It was run at CC/min. In addition, the pressure is 50 torr
Adjustments were made to keep it constant.

Next, ti was poured into a W filament, the filament temperature was set to 2100°C, and diamond was precipitated to a thickness of 1
81III polycrystalline diamond was synthesized.

After polycrystalline diamond was deposited on the substrates as described above, these substrates were removed by grinding. The obtained polycrystalline body was brazed to a steel shank in vacuum at 850° C. using a mug-Cu alloy brazing filler metal. The thickness of the brazing material was 50 μm. A tool was manufactured by processing this, and its cutting performance was examined using the same evaluation method as in Example 1. Table 4 shows the results. As a result, it became clear that a immersed tool could be obtained regardless of the synthesis method.

Table 4 [Effects of the invention] As mentioned above, the hard polycrystalline diamond tool of the present invention has the following effects:
Polycrystalline diamond synthesized by a low-pressure gas phase method and consisting essentially of diamond without a binder phase has a melting point of 70.
Brazed to a support member made of metal and/or alloy with an alloy brazing material at 0 to 1300°C, suitable for various tools such as cutting tools, excavation tools, dressers, etc.
It is a tool with excellent strength, wear resistance, and heat resistance.In particular, unlike conventional sintered diamond, its heat resistance has been greatly improved without reducing strength, so it has a wide range of applications as a tool material. This is something that can be expanded dramatically.

Claims (5)

[Claims] (1) Polycrystalline diamond synthesized by a low-pressure gas phase method and consisting essentially of diamond has a melting point of 700 to 1
A hard polycrystalline diamond tool, characterized in that it is brazed to a support member made of metal and/or alloy using an alloy brazing filler metal at 300°C. (2) Thickness of polycrystalline diamond is 0.1 to 3.0 mm
A hard polycrystalline diamond tool according to claim (1), characterized in that: (3) Claim (1) or (2) characterized in that the thickness of the alloy brazing material is 0.1 to 100 μm.
Hard polycrystalline diamond tools as described in Section 1. (4) The alloy brazing filler metal is Au, Ag, Cu, Ti, and Ta.
Claims (1) to (1) are characterized in that they are high-temperature brazing alloys containing one or more selected from:
The hard polycrystalline diamond tool according to any of item 3). (5) The hard polycrystalline diamond tool according to any one of claims (1) to (3), wherein the support member is made of steel or a sintered carbide alloy.