JPS60121251A - Diamond sintered body for tool and its production - Google Patents

Abstract

PURPOSE:To obtain a titled sintered body which is easily grindable and is hardly chippable with a process for production in which diamond and a small amt. of a ferrous metal having a solvent-catalyst effect are sintered under and at ultra high pressure and high temp. by regulating the size of diamond particles. CONSTITUTION:A sintered body consists of 0.1-5vol% a metal or alloy consisting principally of >=1 kind among iron, Ni and Co and the balance diamond consisting of 10% the diamond having 0.1-<1mu particle size, 20-30% 1-<2mu, 20- 60% and 10-40% 6-10mu. The diamond particles having the grain size distribution regulated in the above-mentioned way and the thin sheet of the metal or alloy contg. >=1 kind among iron, Ni and Co as principal components are joined to each other and are installed in a vessel made of a high melting metal such as Zr. Such vessel is pressurized and heated under and at the temp. under and at which the thin sheets in the vessel act as a solvent-catalyst with the diamond in the thermodynamically stable region of diamond, etc. The objective diamond sintered body for a tool is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting tool, a diamond sintered body suitable for a cutting tool, and a wear-resistant tool, and a method for manufacturing the same.

Diamond sintered bodies have high hardness and wear resistance, and have higher toughness and greater freedom of shape than natural single-crystal diamonds, so they are used in various cutting tools, wire drawing dies, drilling tools, and wear-resistant tools. It is used for such things. The self-sintered structure of such diamond sintered bodies can be roughly divided into two types. One is that the diamond particles are made of a metal, a cermet made of a metal and a high-melting point compound, or a ceramic made of a high-melting point compound as a binder phase. It is a sintered body,
The other type is a sintered body in which diamond particles are directly bonded to adjacent diamond particles.

This internal sound has a problem in that as the amount of the binder phase increases, the hardness of the sintered body decreases, resulting in poor wear resistance and toughness. On the other hand, the latter has higher hardness and strength than the former in order to minimize the destruction of the diamond particles. For this reason, efforts are being made to develop a diamond sintered body in which diamond particles are directly bonded and the use of substances other than diamond particles is minimized or, if possible, completely eliminated. Regarding such a sintered body in which diamond particles are directly bonded, Japanese Patent Publication No. 47-44322
and proposed in Japanese Patent Publication No. 52-12126. 8 Among these, the diamond sintered body according to Japanese Patent Publication No. 47-44322 has a pressure of 55Kb to 80Kb and a temperature of 1600℃ to 2000℃.
A dense sintered body cannot be obtained unless it is sintered at high pressure and high temperature of ℃, and even if a diamond sintered body is obtained by such high pressure and high temperature, the mutual bonding strength between diamond particles is weak and the sintering is difficult. There is a problem that the strength of the structure is poor. On the other hand, the diamond sintered body according to Japanese Patent Publication No. 52-12126 is preferably 90% by volume or more.
0-99% by volume of diamond and solvent-catalytic iron group metal at a pressure exceeding 45Kb, 1400℃-160℃
A sintered body sintered at a temperature of 0°C is disclosed. In the diamond sintered body disclosed in Japanese Patent Publication No. 52-12126, no particular consideration was given to the size of the diamond particles, and an example in which diamond powder of 1325 mesh was used was disclosed. Like this -32
A diamond sintered body consisting of 5 meshes (approximately 45 μm) will break if used in applications where stress is applied locally, such as in cutting tools, because iron group metals exist as pools in some places at the grain boundaries with diamond particles. It becomes the origin of the disease and becomes easily damaged.

In addition, the diamond sintered body produced by this Japanese Patent Publication No. 52-12126 is difficult to grind because it contains coarse diamond particles, and it is difficult to finish it with sharp edges, and its toughness is poor, so it is difficult to use it as a cutting tool. It has the disadvantage of being susceptible to chipping.

The present invention is a diamond sintered body that solves the above-mentioned conventional problems and drawbacks, and in which the size and distribution of diamond particles in the sintered body are strictly controlled, and a solvent-catalytic effect is applied to the diamond. The object of the present invention is to provide a diamond sintered body for tools, which contains a trace amount of an iron group metal or an alloy, and which is an improvement on the diamond sintered body disclosed in Japanese Patent Publication No. 52-12126, and a method for manufacturing the same.

As a result of repeated research to achieve the above objective, the present inventors have developed diamond powder with a strictly controlled particle size distribution and a thin plate of an iron group metal or alloy that has a solvent-catalytic effect on diamond under ultra-high pressure. When sintered at high temperatures, sintering is greatly accelerated and a dense sintered body without pools made of iron group metals or alloys can be obtained. The present invention was completed by experimentally confirming that a sintered body with high hardness and high strength is obtained by directly bonding diamond particles to diamond particles.

The diamond sintered body for tools of the present invention includes iron, nickel,
Metal or alloy containing at least one type of cobalt as a main component 0.1 to 5% by volume and remaining particle size of 0.11 μm or more
10% is less than 1 μm, 20-30% is from 1 μm or more to less than 2 μm, 20-60% is from 2 μm or more to less than 6 μm, and 10% is from 6 μm or more to 10 μm or less.
It is a sintered body of 40% diamond. The diamond sintered body for tools of the present invention is a sintered body in which most of the diamond particles are directly bonded to each other so that the precisely adjusted diamond particles are mutually dispersed and the spaces between each particle are densely packed. become. Most of the diamond particles are directly bonded to each other, and the metal or alloy is extremely small and evenly distributed in the sintered body, so the bonding strength between the particles is high and the hardness and heat resistance of the sintered body are improved. It's increasing. Also 0.
Since it is a sintered body made of fine diamond particles of 1 μm to 10 μm, it has high toughness and excellent grindability.

The method for producing a diamond sintered body for tools according to the present invention is to use 10% of particles having a particle size of 0.1 μm or more to less than I μm and Ilt.
20-30% of those with a diameter of m or more and less than 2 μm and those with a diameter of 2 μm or more
20 to 60% less than 6 μm and 6 μm or more to 10 μm
A diamond powder consisting of 10 to 40% of the following and a thin plate consisting of a metal or alloy containing at least one of iron, nickel, and cobalt as a main component are brought into contact with each other and Zr
, Mo.

The container is placed in a container made of a high melting point metal such as Ta, and the container is placed in the thermodynamic diamond stability region or in the graphite stability region near the diamond-graphite equilibrium line, and the thin plate inside the container acts as a solvent-catalyst on the diamond. This is a manufacturing method that involves heating under pressure and temperature.

At least one of iron, nickel, and cobalt used here
A thin plate made of a metal or alloy containing seeds as a main component penetrates along the grain boundaries of diamond powder during the sintering process, rearranges the diamond particles, and causes the diamond particles to bond with each other through a dissolution and re-precipitation mechanism. while promoting sintering and creating a dense sintered body. At this time, the particle size distribution of the diamond powder is strictly controlled and since it is a fine particle, the spaces between the particles are densely packed and the gaps between the particles are extremely small. The amount of metal or alloy remaining in the sintered body after sintering can be controlled mainly by the particle size distribution of the starting material diamond, which is precisely adjusted, and also by the composition and crystal morphology of the metal or alloy used as the plate. The amount can also be controlled to a small extent by changing the crystallinity (crystallinity or difference in crystallinity) and the pressure and temperature during sintering.

If the particle size distribution of diamond, which is the starting material, is strictly controlled while keeping other manufacturing conditions constant, even if there is a large amount of thin plate made of metal or alloy as starting material, excess metal or alloy will be removed during the sintering process. The metal or alloy that remains on the surface of the sintered body without penetrating into the diamond grain boundaries and that remains on the surface of the sintered body after sintering can be removed by grinding or the like to obtain the desired sintered body. Also, diamond powder and iron,
By placing a thin plate containing at least one of nickel and nickel as a main component, and a substrate made of cemented carbide, cermet, etc. in a container and sintering it under the same high pressure and high temperature, [the tool of the present invention] A composite sintered body in which the diamond sintered body and the base body are integrated is obtained. When making a composite sintered body in this way, W, Mo, and T are added between the diamond sintered body and the base.
The interposition of an intermediate layer made of a high melting point metal such as a, Nb, etc. has the effect of improving the adhesive bond strength between the diamond sintered body and the substrate.

Among the methods for manufacturing the diamond sintered body for tools of the present invention, the sintering method involves setting a container containing the starting material in an ordinary belt-type or girdle-type high-pressure and high-temperature device at 40 to 60K.
It can be sintered at a pressure of b and a temperature of 1200-1600°C. When sintering in a closed high-pressure apparatus, gases generated during the sintering process tend to inhibit sintering. The manufacturing method of the present invention, which uses a thin plate made of metal or alloy as a starting material, has the effect of preventing the generation of gas during the sintering process because there is less deposits that become gas components such as oxidized and adsorbed water. Furthermore, using a material capable of absorbing gas, such as Zr or Ta, for the container is effective in accelerating sintering and producing a dense sintered body. Furthermore, as a method to prevent the generation of gas during the sintering process, the entire container containing the starting materials is preheated in a vacuum to a temperature below the sintering temperature, for example, about 500°C to 1000°C, and then sintered under the above conditions. Then it works.

Next, a diamond sintered body for tools and a method for manufacturing the same according to the present invention will be explained in detail according to Examples.

Example 1 In a Zr cylindrical container with an inner diameter of 11ψ and a wall thickness of 0.15g,
．． 1 μm or more to less than 1 μm is 10%, 1 μm or more to less than 2 μm
25% is less than m, 15% is 2 μm or more and less than 4 μm, 4
15% is from 6 μm to less than 6 μm, and 15% is from 6 μm to 10 μm
Filled with 0.25t of diamond mixed powder with a particle size distribution of 35%, and then packed with a diameter of lOψ and a thickness of O, O-
Place a 5-order Co disk in contact with diamond powder zrf
Two sets of containers covered with R disks were set in a high-pressure device and held at a pressure of 45 Kb and a temperature of 1400°C for 30 minutes, then the temperature was rapidly cooled to below 1000°C while maintaining the pressure at 45 Kb. Thereafter, the pressure and temperature were lowered to normal pressure and room temperature, and the sintered body was taken out from the container. The sintered body thus obtained is
Diamond particles are bonded to each other, almost no Co phase is observed, and as a result of EPMA analysis, the amount of Co is 0.5.
It was % by volume. The hardness of this sintered body is 7 on the Knoop hardness scale.
It showed 800.

Example 2 In a container similar to Example 1, a cemented carbide (WC-10%Co) substrate with a diameter of 11ψ and a thickness of 1.8 mm, a W disk with a diameter of 11ψ and a thickness of 0.1 mm, and a grain size were placed. Distribution is 0.1 μm or more
10% is less than 1 μm, 20% is 1 μm or more and less than 2 μm
, 20% or more and less than 4 μm, 4 μm or more and less than 6 μm
30% is less than m, 10% is 6 μm or more and less than 8 μm, 8
Two sets of containers packed with 10% diamond mixed powder of 10% of the diameter of μm or more and 10 μm or less and Co disks of diameter IIψ and thickness O and I mm and covered with Zr disks are placed in a high-pressure device. After setting the pressure at 50Kb and holding it at a temperature of 1500℃ for 10 minutes, the pressure was kept at 50Kb and the
The sintered body was rapidly cooled to 0° C. or lower, and then the pressure and temperature were lowered to normal pressure and room temperature, and the sintered body was taken out from the container. In the thus obtained composite sintered body, the diamond sintered body, the W intermediate layer, and the cemented carbide base were firmly adhered to each other.

The diamond particles in the diamond sintered body were bonded to each other, almost no intervening lines of CO were observed, and as a result of EPMA analysis, the amount of Co was 2% by volume. The hardness of the diamond sintered body was 7500 on Knoop hardness. This composite sintered body was laser cut and brazed to the cutting edge of a CIS standard DSOX150 tip made of cemented carbide to produce a cutting tool, and one commercially available diamond sintered body was added for comparison as shown below. A cutting test was conducted under the following conditions.

Cutting test conditions by turning Rigid material Silicon nitride sintered body Cutting speed 20 m/min Depth of cut 0.5 m Feed rate 0.02 m1/rev Cutting time 5 m1n Cutting method Dry test results showed that the diamond sintered body for tools of the present invention The average flank wear amount is 0.35 am, whereas the average flank wear amount of the commercially available diamond sintered body added for comparison is 0.65 am.
Minute chipping occurred on the cutting edge.

Example 3 In a container similar to Example 1, a cemented carbide substrate similar to Example 1, a Mo disk with a diameter of 11 ψ mm and a thickness of 0.1 mm, and a grain size distribution of 0.1 μm or more to less than 1 μm were placed. %, 1μm
25% is between 2 μm and less than 4 μm, 30% is between 4 μm and less than 6 μm, 5% is between 6 μm and less than 8 μm, and 5% is between 8 μm and less than 10 μm.
Diamond mixed powder with diameter 11ψ and thickness 0.06
mm of Ni-based amorphous alloy (NisI CO23Crto
Mo7 Fes, 513a, s) disks were stacked and packed in this order, covered with a Zr disk, and preheated by holding at 700'C for 30 minutes in a 10-4 Hf vacuum. Immediately set this Zr container in a high pressure device and
pressure, 50K after holding for 10 minutes at a temperature of 1320℃
The sintered body was rapidly cooled to 1000° C. or lower at the pressure shown in b, and then the pressure and temperature were lowered to normal pressure and room temperature, and the sintered body was taken out from the container. In the thus obtained composite sintered body, the diamond sintered body, the Mo intermediate layer, and the cemented carbide base were firmly adhered to each other.

The diamond particles in the diamond sintered body are bonded to each other, and the hardness of the diamond sintered body is 7 on the Knoop hardness scale.
The diamond sintered body for tools of the present invention has high hardness and high toughness, and has about twice the life of conventional diamond tools when used as a cutting tool. The manufacturing method allows sintering to be performed at pressures and temperatures that are easy for industrial production, and in a short period of time.

Patent applicant: Toshiba Yungaroy Corporation

Claims (2)

[Claims] (1) A sintered body consisting of 0.1 to 5% by volume of a metal or alloy containing at least one of iron, nickel, and cobalt as a main component and the remainder diamond, and the diamond particles are 0.1 μm or more to 1 μm in size. less than 10% and 1μ
20-30% of those with a diameter of m or more and less than 2 μm and those with a diameter of 2 μm or more
20 to 60% less than 6 μm and 6 μm or more to 10 μm
A diamond sintered body for tools, characterized by comprising 10 to 40% of the following: (2) Particles with a particle size of 0.1 μm or more and less than 1 μm 1
0% and 1 μm or more to less than 2 μm 20-30% and 2
A thin plate made of a metal or alloy containing at least one of iron, nickel, and cobalt as a main component, and a diamond powder consisting of 20 to 60% of diamond powder of 20 to 60% of diamond powder of μm or more and less than 6 μm and 10 to 40% of diamond powder of 6 μm or more to less than 10 μm. are placed in contact with each other in a container, and the container is heated under pressure to a temperature within the thermodynamic diamond stability region or within the graphite stability region near the diamond-graphite equilibrium line and above the temperature at which the thin plate and the diamond powder react. A method for manufacturing a diamond sintered body for tools, characterized by: