JPS61125739A - Diamond sintered article for tool and manufacture thereof - Google Patents

Abstract

PURPOSE:To assure heat resistance and wear resistance by constituting the captioned diamond sintered article with sintered diamond having the contents of the diamond more than 93 volume % and less than 99 volume % and a carbide alloy base material. CONSTITUTION:Sintered diamond more than 93 volume % and less than 90 volume %. A remaining fraction thereof has 0.1 to 3 volume % in total of at least one of metal of 4a, 5a, and 6a groups in a periodic table or carbide and metal of iron group, and 0.5 to 7 volume % of holes. In addition, the sintered diamond and the carbide alloy base material are joined with each other via an intermediate joint layer, which intermediate layer has its thickness less than 0.5mm. Accordingly, a base material composed of the sintered diamond and the carbide alloy as decribed above are provided, whereby rigidity of the carbide alloy is added to the sintered diamond.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diamond sintered body used in various tools such as cutting tools, excavation tools, and dressers, and a method for manufacturing the same.

[Conventional technology 1] A diamond sintered body obtained by sintering diamond powder with metal as a binder under ultra-high pressure and high temperature where diamond is stable has the characteristics of diamond, which has the highest hardness among tool materials. However, unlike single-crystal diamond, it does not break due to low stress due to cleavage. Therefore, it is used as a tool in many fields such as cutting tools, wire drawing dies, dressers, and rock excavation tools. This diamond sintered body has various structures and shapes depending on the purpose, but cutting tools, dressers, and rock drilling tools generally have a layer of diamond sintered body made of a highly rigid base material such as cemented carbide. The one joined to is used.

A sintered body having the above structure is disclosed, for example, in JP-A-46-
A sintered body in which a layer of a diamond sintered body is directly bonded to a WCC cemented carbide base material, such as No. 5204, and
Examples are known, such as No. 45313 or No. 56-5506, in which a layer of a diamond sintered body is bonded to a base material such as cemented carbide via an intermediate bonding layer.

Many of the diamond sintered body layers of the above-mentioned sintered bodies currently in use use a ferrous metal such as CO as a binder for diamond particles. Ferrous metals are used as solvents when synthesizing diamond from graphite, and they dissolve a portion of the diamond powder during sintering under ultra-high pressure and serve to firmly sinter the diamond particle layer. It is considered.

The ferrous metal may be mixed with diamond powder before sintering, or as disclosed in JP-A-46-5204, a binder melt of the base material WC-Co is mixed into diamond powder during sintering. Diamond sintered bodies such as this one, for which a method of infiltration is also known, have excellent wear resistance and strength, and exhibit excellent performance in applications that conventionally used single-crystal diamond. There are major limitations in this respect.

Graphitization occurs from the surface of diamond at temperatures above 900°C in the atmosphere, but graphitization occurs at temperatures above 140°C in vacuum or inert gas.
Graphitization is difficult to occur even at temperatures around 0°C. However, when the conventional diamond sintered body mentioned above is heated, the tool performance deteriorates at a temperature of about 750°C. This means that under usage conditions such as cutting tools and excavation tools where the cutting edge becomes hot during use, the performance naturally deteriorates. The reason why conventional diamond sintered bodies deteriorate at lower temperatures than diamond single crystals is that there is a large difference in the coefficient of thermal expansion between the ferrous metal binding material and diamond, and the thermal stress in the sintered bodies increases due to heating. This is because the diamond structure is destroyed and the ferrous metal has the effect of promoting graphitization of diamond.

As a method to improve the heat resistance of diamond sintered bodies, we create sintered bodies that are not bonded to a base material such as cemented carbide.
A method of immersing this in aqua regia and heating it to elute the metal bonding phase in the sintered body has been considered (Japanese Patent Laid-Open No. 53-1
No. 14589). It is thought that this allows the diamond sintered body to have heat resistance that can withstand heating up to a temperature of 1200°C.

In the diamond sintered body disclosed in JP-A-53-114589, since the metal bonding phase is eluted by acid treatment, there are about 8% pores by volume. Therefore, the strength of the sintered body is significantly reduced, and when used in tools, it lacks toughness. Furthermore, in the method described in this prior art, the cemented carbide that imparts toughness to the sintered diamond is not bonded, and as a result, it cannot exhibit sufficient performance as an excavator. Furthermore, this method is subject to significant restrictions when bonding the diamond sintered body to the tool support, making it difficult to obtain a strong bond.

Therefore, the object of this invention is to further improve heat resistance,
Another object of the present invention is to provide a diamond sintered body for tools that has excellent strength and wear resistance.

c) Means and action for solving the problem] When using a diamond sintered body as a tool, for example, when using a diamond sintered body for excavating hard rocks or cutting ceramics, the diamond sintered body is used as the cutting edge. High stress is applied to the area, and the temperature rises. Therefore, sintered diamond needs to be heat resistant and have high strength and toughness.

The inventors of the present application have conducted research into producing a diamond sintered body having the above-mentioned characteristics.
The diamond content is 93% by volume, less than 99% by volume, and the remainder belongs to 4a of the periodic table.

5a, 6a group metal or carbide and/or iron group metal 0.1 to 3% by volume, vacancies 0.5% to 7% by volume, or 0.5% by volume and 0.5% by volume of pores and/or borides. A diamond sintered body in which sintered diamond containing 0.005 to 0.25% by volume is bonded to a base material made of cemented carbide directly or through an intermediate bonding layer has excellent heat resistance, strength, and toughness. It was found that both were excellent.

In order to improve the heat resistance of sintered diamond, the iron group metal serving as the binder may be removed as described above. However, the locations where the binder was present become voids due to the removal of the iron group metal. By the way, in sintered diamond,
There is a relationship between the strength and pores as shown in FIG. In other words, as the number of pores increases, the strength of sintered diamond decreases, but when the number of vacancies is 5% or more and 8% or less, the strength decreases rapidly, and when the vacancies are 8% or less, the rate of decrease in strength becomes smaller. .

Generally, the strength required for sintered diamond varies depending on its use and the strength of the workpiece. For example, for drilling relatively soft rocks, cutting ceramics, etc., if the strength is more than 1.5 times that of commercially available heat-resistant sintered diamond,
Its performance is significantly improved. Therefore, for such applications, the vacancy content must be at least 7% or less, and the diamond content m must be at least 93% m by volume.
A sticky substance is required. If the pore content is less than 5% by volume, the strength of sintered diamond is approximately three times that of commercially available heat-resistant sintered diamond, and it has excellent performance in drilling hard rocks and cutting high-hardness ceramics. is desirable.

This invention includes the above-described sintered diamond and a base material made of cemented carbide, and the toughness of cemented carbide is added to the sintered diamond. Therefore, it is suitable for applications where high stress is applied to the cutting edge, such as cutting hard ceramics or excavating hard rock.

Note that when sintered diamond is directly bonded to cemented carbide, a layer rich in iron group metals is formed at the bonded portion, and during acid treatment, the iron group metals in this area are eluted, resulting in a bond failure. Strength may decrease. Therefore, preferably, the sintered diamond and the cemented carbide base material are
Such @ It becomes possible to prevent eclipse.

Therefore, a diamond sintered body with excellent bonding strength can be obtained. The thickness of this intermediate bonding layer is 0.511
IIli! The lower end is preferred. If it exceeds 0.5 mm, when used as the cutting edge of a drilling tool, etc.
This is because the intermediate bonding layer is worn out.

In the manufacturing method of this invention, the raw material diamond powder is
By heating at a high temperature of 00℃ or higher to graphitize the surface of the diamond powder, and by using a mixture of diamond powders with different particle sizes as raw materials, we can create a dense sintered product with a diamond content of over 93% by volume. It is said that it is possible to obtain a body. However, if the diamond content exceeds 99%, iron group metals become insufficient and sintered diamond of sufficient strength cannot be produced.

In the sintered diamond of this invention, as shown in Figure 1, it is preferable to have as few pores as possible, but in order to obtain a sintered body with high strength, it is necessary to is also necessary.

Therefore, in this invention there is a minimum of 0.5% vacancy.

The diamond powder used in the production of the diamond sintered body of this invention has an average maximum particle diameter of 40 to 60.
A mixture of 30-40% by volume of particles with a particle size of a/2 and the remainder with a particle size of a/3-a/1000 is
This is preferred because it allows a high diamond content to be obtained.

The sintered diamond of this invention contains diamonds of various particle sizes, including diamonds 48 and 5a of the periodic table,
If no group 6a metal or carbide is contained, abnormal accumulations of iron group metals occur particularly near the fine diamond particles, and when the metals are eluted, these areas become pores. Therefore, if metal or carbide is contained, the strength will be further improved. The content of the iron group metal, metals of groups 4a, 5a, and 6a of the periodic table, or carbides is preferably 0.1 to 3% by volume. This is because if the m content exceeds 3 vol. %, cracks may occur due to thermal expansion adhesion with diamond and graphitization of diamond will occur, resulting in a decrease in heat resistance. In addition, it is preferable that this content be as small as possible, but since iron group metals remaining in the diamond raw material are practically impossible to elute, a minimum of 0.1% by volume of iron group metals, etc. should remain in the sintered body. It turns out.

In the sintered diamond of this invention, in particular, the carbide is WC
Or has the same crystal structure as this (Mo, W)
It has been found that when C, the toughness, abrasion resistance and heat resistance are excellent.

Further, the sintered body of the present invention has a capacity of 0°005
When containing ~0.25% boron and/or boride, the properties are further improved. usually,
Diamond particles are sintered by melting or precipitating diamond particles using a catalyst such as an iron group metal under ultra-high pressure and high temperature. When at least one of boron and borides is added, borides of iron group metals are formed, which lowers the melting point and increases the melt deposition rate. It can be inferred that this is due to the growth of diamond particles, and the holding power of the diamond particles has improved. When the boron or boride content is less than 0,005%, the formation of the diamond skeleton is slow. On the other hand, if the boron or boride content exceeds 0.25%, a large amount of boron will invade the diamond skeleton, reducing the strength of the diamond skeleton.

The diamond powder used in the sintered diamond of this invention can be either synthetic diamond or natural diamond.

In the manufacturing method of the present invention, the periodic table 4a.

To contain metals or carbides of groups 5a and 6a, use diamond powder and items 48 and 53 of the periodic table.

Group 6a carbides or metals as well as l”e, co
.

An iron group metal powder such as Ni or a powder obtained by adding boron or boride to the powder is uniformly mixed using a means such as a ball mill. This iron group metal is not mixed in advance, but during sintering,
Infiltration may be carried out by contacting a member made of an iron group metal.

In addition, the inventors' earlier application (patent application No. 11852-5188)
As disclosed in No. 1), the pot and ball for ball milling are made of a sintered body of carbides of groups 4a, 5a, and 5a of the periodic table mixed with iron group metals, and diamond At the same time as the powder is ground in a ball mill, a fine powder of a sintered body of carbides of groups 4a, 5a, and 5a of the periodic table and iron group metals may be mixed into the pot and ball.

The mixed powder is heated to a high temperature of 1,300°C or higher to graphitize some of the diamonds, and is filled into the FFL hard alloy so that it is in contact with the FFL hard alloy directly or through an intermediate bonding layer. It is sintered under stable conditions and simultaneously bonded to cemented carbide. It is necessary to sinter at a moisture content higher than that at which a eutectic liquid phase appears between the iron group metal used at this time and a compound such as a carbide.

The sintered diamond heated as described above is then treated with an oxidizing liquid. As the oxidizing liquid, for example, heated aqua regia, nitric acid or hydrofluoric acid can be used. Such an oxidizing liquid treatment causes iron group metals in sintered diamond and metals of the periodic table 4a and 5a.

It becomes possible to elute part of the metal or carbide of 6aM. At the same time, when a plugging material made of cemented carbide is treated with sintered diamond in an oxidizing liquid, an oxide film is formed on the surface of the cemented carbide, and therefore the elution of iron group metals in the cemented carbide is prevented. Prevented.

However, in the treatment with the oxidizing liquid as described above, it is also possible to immerse only the sintered diamond layer in the liquid.

Applications of the diamond sintered body of the present invention include, in addition to pits, ceramic cutting tools, dressers, and the like.

[Example] This will be explained in detail using examples.

Example 1 Average particle size 80 Atm, 35 μs, 20j, Zl and 5-0.2 μl diamond powder in 45:35:
Blended at a ratio of 1:1 and then WC-C.

Grinding was carried out for 5 minutes using a pot and a ball made of cemented carbide. This powder was heated in vacuum at a temperature of 1400° C. for 30 minutes. Next, add WC-12% to an MO container.
A powder containing 60 volume 1% of cubic type nitride flIX with the balance consisting of TiN and AfL was coated on a CO disk, and then the above mixed powder was filled, and a Co plate was placed on the finished powder. @Place and contact, ultra-high pressure and high temperature siW! First, a pressure of 55 kb was applied using a vacuum cleaner, followed by heating to a temperature of 1460° C. and holding it for 10 minutes. When the sintered body thus obtained was taken out of the container and observed, it was found that the sintered diamond was firmly bonded to the cemented carbide base material through an intermediate bonding layer with a thickness of 0.51 al. Ta.

Next, only this sintered diamond was analyzed by chemical analysis, and the M content of diamond, WC, and GO was measured, and the results were 96.0% by volume, 0.15% by volume, and 0.15% by volume, respectively.
It was 3.85% by volume.

Next, cemented carbide! The above-mentioned sintered diamond bonded to the S material via the intermediate bonding layer is dredged in heated aqua regia,
After 50 hours of treatment, Co was released from the sintered diamond.
and a part of WC elutes, resulting in diamond 96.0
The composition was 141% by volume, WCo, 141% by volume, 0.8% Co, and 3.06% by volume of pores, but the cemented carbide base material was oxidized only on the surface, and the internal Co was oxidized. It was observed that very little elution occurred. Also, middle school 11th
No corrosion of the first layer was observed.

The above-mentioned chip was processed as a cutting chip, and Si with a Vickers hardness of 1800 was cut at a cutting speed of 8011.
/min, depth of cut 1mm, feed 0.1111/rotation/dry type 1
Cut for 0 minutes.

For comparison, the above procedure was carried out on a sintered body before aqua regia treatment and on a commercially available heat-resistant diamond sintered body with 8% by volume of pores remaining and to which a cemented carbide base material was not bonded. Cutting was carried out under the same conditions as in the example.

As a result, the flank wear width of the diamond tip of this example was 0.15+u, whereas it was 0.351 of the diamond tip without CO elution. Also,
Commercially available sintered diamond breaks after 30 seconds of cutting, making it impossible to cut.

Example 2 Average particle size 8C) cza+, 40. czm, 15
ttm and 0.5 μm diamond particles in a 5:3
: They were blended at a ratio of 2:1. To this powder, various iron group metals shown in Table 1 and peripheral mw Tables 4a, 5a,
Group 6a metals or carbides were mixed to form a finished powder. Next, these finished powders were heated to a temperature of 1350° C. in a vacuum to graphitize some of the diamond particles. A WC-15% CO alloy was placed in a container made of the same material, filled with the finished powder, and sintered at a temperature of 58 kb and 1500°C. Each of the sintered bodies thus fitted was taken out from the Ta container, only the sintered diamond core was immersed in an electrolytic solution, and an electric current was applied to dissolve the iron group metals from the sintered diamond.

Table 1 also shows the number of pores in the sintered diamond.

In each of the above-mentioned drawings, a core bit was created by brazing a 5-gold wire onto a pit body using a cemented carbide base material.

For comparison, a 9-Fes set core bit using natural diamond and a core bit using sintered diamond from which iron group metals were not eluted were prepared.

For each test piece above, -axial compressive strength 1600-1700
K(1/CI' (7) Expenditure We excavated at 500 revolutions/min. The excavation speed and service life are shown in Table 2.

(Margins below) Table 1 *1: Unit + t * m% *2: Perimeter Table 48, 5a, 6a group metal carbides *3
: Fa place I! I! Diamond powder with a pore volume of 11" LL and an average particle size of 0.8 .mu.m and boron powder were ground and mixed using a WC-Co cemented carbide pot and ball. This powder and average grain IT! 50μ sho, 25
1:5:3 of μl and 10μm diamond powder
: Mixed at a ratio of 1:1, then heated in vacuum at a temperature of 1450°C for 1 hour, and then treated in the same manner as in Example 1 to produce 55 kl)
The sintering was carried out under conditions of , 1450°C. When this sintered body was analyzed, it was found that 96.0% by volume of diamond, GO3
It was confirmed that the sintered body was composed of 65% by volume, 1% by volume of WCo, 2% by volume of WCo, and 05% by volume of -O. When this sintered body alone was treated in heated aqua regia, 3.4% by volume of pores were generated.

Using this sintered body, cut alumina ceramics with a Vickers hardness of 2300 at a speed of 80 m/min and a depth of cut of 211.
111, feed: O, l+i/revolution, and cutting was carried out for 15 minutes using water-soluble cutting oil.

For comparison, commercially available heat-resistant diamond with a particle size of 40 μm to 60 μm and 8% by volume of pores, to which no cemented carbide was bonded, was used for cutting.

As a result, the flank wear width of the diamond sintered body of the present invention was 0.25111, whereas the commercially available heat-resistant diamond suffered from chipping after 2 minutes of cutting.

U21 By changing the blending ratio of diamond particles with different particle sizes and the graphitization treatment conditions, various diamond sintered bodies with a maximum particle size of 60 μm and different diamond contents were created in the same manner as in Example 3, and then Only the post-sintered diamond was acid-treated to prepare a heat-resistant diamond chip. Table 3 shows the diamond content and pore content of each sintered diamond.

(Left below) Each of the sintered bodies M-R shown in Table 3 was processed into a cutting chip with a compressive strength of 900 to 1000/
cm' of andesite was wet-cut for 20 minutes at a cutting speed of 150 @/min, depth of cut +211, feed: 0.3111/rotation, and the flank wear width was measured. The results are shown in Figure 2.

As is clear from FIG. 2, the flank wear width of samples M, N, O, and P, in which the volume of pores is 7% by volume or less, is that of sample 0.0, in which the volume of pores is 7% by volume or more. It can be seen that it is much less than R.

[Effect of the Invention 1 As described above, according to the present invention, it is possible to obtain a diamond sintered body for tools that has even better heat resistance, strength, toughness, and wear resistance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between compressive strength and pore volume in a heat-resistant diamond sintered body from which the binder phase has been eluted. FIG. 2 is a diagram showing the results of an andesite cutting test on a heat-resistant diamond sintered body. Patent applicant Sumitomo Electric Industries, Ltd.! ! , 1) ``Iyamo'' hole width in Jilin Middle 2) @2 Figure

Claims (42)

[Claims] (1) The diamond content exceeds 93% by volume, and
9% by volume or less, with the remainder being 4a, 5a, and 6 of the periodic table.
A sintered diamond comprising a total of 0.1 to 3% by volume of at least one of a group A metal or carbide and an iron group metal, and 0.5% to 7% by volume of voids, and a cemented carbide base. A diamond sintered body for tools made of materials. (2) The diamond sintered body for a tool according to claim 1, wherein the sintered diamond and the cemented carbide base material are bonded via an intermediate bonding layer. (3) The diamond sintered body for a tool according to claim 2, wherein the intermediate bonding layer has a thickness of 0.5 mm or less. (4) The diamond sintered body for a tool according to claim 1, wherein the sintered diamond is directly bonded to a cemented carbide base material. (5) The diamond content exceeds 95% by volume and is 99%
% by volume or less, and the remaining pores are 0.5% by volume or more and less than 5% by volume, the diamond sintered body for tools according to any one of claims 1 to 4. (6) The carbide of groups 4a, 5a, and 6a of the periodic table is
WC or (MoW)C with the same crystal structure as WC
A diamond sintered body for a tool according to any one of claims 1 to 5. (7) The content of diamond is more than 93% by volume and not more than 99% by volume, and the balance is a total of 0.1 to 0.1% or more of at least one of metals or carbides of Groups 4a, 5a, and 6a of the periodic table, or carbides, and iron group metals. 3% by volume, 0.5% to 7% by volume of voids, and a total of 0.005 to 0.25% by volume of at least one of boron and boride; and a cemented carbide. A diamond sintered body for tools, comprising a base material. (8) The sintered diamond is bonded to the cemented carbide base material via an intermediate bonding layer.
A diamond sintered body for tools as described in . (9) The diamond sintered body for a tool according to claim 8, wherein the intermediate bonding layer has a thickness of 0.5 mm or less. (10) The diamond sintered body for a tool according to claim 7, wherein the sintered diamond is directly joined to the cemented carbide base material. (11) the diamond content exceeds 95% by volume;
99% by volume or less, and the remaining pores are 0.5% by volume or more and less than 5% by volume, Claims 7 to 1
The diamond sintered body for tools according to any one of item 0. (12) The carbide of groups 4a, 5a, and 6a of the periodic table has WC or the same crystal structure as WC (MoW)C
A diamond sintered body for a tool according to any one of claims 7 to 11. (13) Create diamond powder or a mixed powder of diamond powder and metals or carbides of Groups 4a, 5a, and 6a of the periodic table and iron group metals, and heat the diamond powder in the raw material powder at a temperature of 1300°C or higher. A part of the diamond is graphitized, and then brought into contact with a cemented carbide, and then the diamond is brought into contact with an iron group metal or a sintered carbide of groups 4a, 5a, and 6a of the periodic table, using an ultra-high pressure and high temperature device. By hot-pressing the diamond under high temperature and high pressure to create a sintered body, and treating the sintered body with an oxidizing liquid, iron group metals in the sintered diamond and elements 4a, 5a, and 5a of the periodic table can be removed. The diamond content is more than 93% by volume and less than 99% by volume, and the remainder is from the fourth group of the periodic table.
A sintered diamond containing a total of 0.1 to 3% by volume of at least one of metals or carbides of groups A, 5a, and 6a, and iron group metals, and 0.5% to 7% by volume of vacancies. A method for manufacturing a diamond sintered body for tools, comprising a hard metal base material. (14) A method for manufacturing a diamond sintered body for a tool according to claim 13, wherein the diamond and the cemented carbide are brought into contact with each other via an intermediate bonding layer when the diamond and the cemented carbide base material are brought into contact with each other. . (15) In the treatment with the oxidizing liquid, an oxide film layer is formed on the surface of the cemented carbide, thereby preventing elution of iron group metals in the cemented carbide. A method for producing a diamond sintered body for tools as described in . (16) During the treatment with the oxidizing liquid, only the sintered diamond layer is immersed in the oxidizing liquid, thereby preventing elution of iron group metals in the cemented carbide.
The method for producing a diamond sintered body for tools according to item 3 or 14. (17) the diamond content exceeds 95% by volume;
99% by volume or less, and the remaining pores are 0.5% by volume or more and less than 5% by volume, manufacturing a diamond sintered body for tools according to any one of claims 13 to 16. Method. (18) The carbide of groups 4a, 5a, and 6a of the periodic table has WC or the same crystal structure as WC (MoW)
The method for manufacturing a diamond sintered body for tools according to any one of claims 13 to 17, wherein the diamond sintered body is C. (19) A mixed powder of diamond powder and an iron group metal, or a diamond powder and a metal or carbide of Groups 4a, 5a, or 6a of the periodic table and an iron group metal is prepared, and 130
After graphitizing a portion of the diamond in the raw material powder at a temperature of 0°C or higher, the diamond is brought into contact with the cemented carbide, and heated under high temperature and pressure at a stable temperature using an ultra-high pressure/high temperature device. By pressing to create a sintered body and treating the sintered body with an oxidizing liquid, some of the iron group metals and metals of groups 4a, 5a, and 6a of the periodic table or carbides in the sintered body are removed. The diamond content is more than 93% by volume and not more than 99% by volume, and the remainder is at least one of metals or carbides of groups 4a, 5a, and 6a of the periodic table and iron group metals. The total is 0.
1 to 3% by volume, and 0.5% to 7% by volume of voids
A method for manufacturing a diamond sintered body for tools, comprising a sintered diamond consisting of the following and a base material consisting of a cemented carbide. (20) The diamond and the base material made of cemented carbide are in contact with each other via an intermediate bonding layer.
The method for producing a diamond sintered body for tools according to item 9. (21) The method for manufacturing a diamond sintered body for a tool according to claim 19 or 20, wherein the intermediate bonding layer has a thickness of 0.5 mm or less. (22) The method for manufacturing a diamond sintered body for a tool according to claim 19, wherein the diamond and the cemented carbide base material are brought into direct contact. (23) When treating the oxidized liquid, an oxide film layer is formed on the surface of the cemented carbide base material, thereby preventing elution of iron group metals in the cemented carbide base material, claim 19. 23. A method for producing a diamond sintered body for tools according to any one of items 22 to 22. (24) When treating the oxidizing liquid, only the sintered diamond layer is immersed in the liquid, thereby preventing elution of iron group metals in the cemented carbide base material.
A method for producing a diamond sintered body for tools according to items 22 to 22. (25) Claims 19 to 24, wherein the diamond content is more than 95% by volume and not more than 99% by volume, and the remaining pores are 0.5% by volume or more and less than 5% by volume. A method for producing a diamond sintered body for tools according to any one of paragraphs. (26) The carbides of groups 4a, 5a, and 6a of the periodic table have the same crystal structure as WC or WC (MoW)C
A method for manufacturing a diamond sintered body for tools according to any one of claims 19 to 25. (27) Mixed powder of diamond powder and boron or boride, or diamond powder and periodic table items 4a and 5
A, a mixed powder of group 6a metals or carbides, iron group metals, and boron or borides is prepared, a part of the diamond in the raw material powder is graphitized at a temperature of 1300°C or higher, and then a cemented carbide base is formed. Further, an iron group metal or a sintered carbide of groups 4a, 5a, and 6a of the periodic table is brought into contact with the diamond, and the diamond is hot-pressed using an ultra-high pressure and high temperature device under high temperature and pressure at which the diamond is stable. By preparing a sintered body and treating the sintered body with an oxidizing liquid, some of the iron group metals and metals of groups 4a, 5a, and 6a of the periodic table or carbides in the diamond sintered body are removed. The diamond content is more than 93% by volume and not more than 99% by volume, and the remainder is at least a metal or carbide of Group 4a, 5a, or 6a of the periodic table and an iron group metal. Sintered material consisting of 0.1 to 3% by volume of one in total, 0.005 to 0.25% by volume of at least one of boron or boride, and 0.5 to 7% by volume of voids. A method for manufacturing a diamond sintered body for tools, comprising diamond and a base material made of cemented carbide. (28) The method for manufacturing a diamond sintered body for a tool according to claim 27, wherein the diamond and the cemented carbide are brought into contact with each other via an intermediate bonding layer. (29) The method for manufacturing a diamond sintered body for tools according to claim 28, wherein the intermediate bonding layer has a thickness of 0.5 mm or less. (30) The method for manufacturing a diamond sintered body for a tool according to claim 27, wherein the diamond and the cemented carbide are brought into direct contact. (31) The diamond sintered body for tools according to any one of claims 27 to 30, which forms an oxide film layer on the surface of the cemented carbide base material during the treatment with the oxidizing liquid. Production method. (32) During the treatment with the oxidizing liquid, only the sintered diamond layer is immersed in the oxidizing liquid, thereby preventing elution of the iron group metal from the cemented carbide base material. The method for producing a diamond sintered body for tools according to any one of Items 27 to 30. (33) the diamond content exceeds 95% by volume;
Production of a diamond sintered body for tools according to any one of claims 27 to 32, wherein the pores are 99% by volume or less and the remaining pores are 0.5% by volume or more and less than 5% by volume. Method. (34) The carbide of groups 4a, 5a, and 6a of the periodic table has WC or the same crystal structure as WC (MoW)
The method for manufacturing a diamond sintered body for a tool according to any one of claims 27 to 33, wherein the diamond sintered body is C. (35) A mixed powder of diamond powder and an iron group metal and at least one of boron and borides, or a diamond powder and a metal or carbide of Groups 4a, 5a, or 6a of the periodic table, an iron group metal, and boron and boride. After creating a mixed powder with at least one of the above, graphitizing a part of the diamond in the raw material powder at a temperature of 1300°C or higher, bringing it into contact with cemented carbide, and stabilizing the diamond using an ultra-high pressure and high temperature device. By hot pressing under high temperature and high pressure to create a sintered body, and treating the sintered body with an oxidizing liquid, iron group metals and groups 4a, 5a, and 6a of the periodic table in the diamond sintered body can be removed. The diamond content is more than 93% by volume and not more than 99% by volume, and the remainder is metals or carbides from Groups 4a, 5a, and 6a of the periodic table. A total of at least one of iron group metals from 0.1 to 3% by volume, at least one of boron and boride from a total of 0.005 to 0.25% by volume, and vacancies of 0.5% to less than 7% by volume. A method for manufacturing a diamond sintered body for a tool, comprising: a sintered diamond made of sintered diamond; and a base material made of a cemented carbide. (36) The method for producing a diamond sintered body for workers according to claim 35, wherein the diamond and the cemented carbide are brought into contact with each other via an intermediate bonding layer. (37) The method for manufacturing a diamond sintered body for tools according to claim 36, wherein the intermediate bonding layer has a thickness of 0.5 mm or less. (38) The method for manufacturing a diamond sintered body for a tool according to claim 35, wherein the diamond and the cemented carbide are brought into direct contact. (39) In the treatment with the oxidizing liquid, an oxide film layer is formed on the surface of the cemented carbide, thereby preventing elution of iron group metals in the cemented carbide. A method for producing a diamond sintered body for tools according to any one of Item 38. (40) In the treatment with the oxidizing liquid, only the sintered diamond layer is immersed in the oxidizing liquid, thereby preventing elution of the iron group metal in the cemented carbide. The method for producing a diamond sintered body for workers according to any one of Item 38. (41) Claims 35 to 35, wherein the diamond content is more than 95% by volume and not more than 99% by volume, and the remaining pores are 0.5% by volume or more and less than 5% by volume. A method for producing a diamond sintered body for tools according to any one of Item 40. (42) The carbide of groups 4a, 5a, and 6a of the periodic table has WC or the same crystal structure as WC (MoW)
The method for manufacturing a diamond sintered body for tools according to any one of claims 35 to 41, wherein the diamond sintered body is C.