JPH0474765A - Sintered material of whisker combined diamond and production thereof - Google Patents

Abstract

PURPOSE:To prevent occurrence of cracks and large and small damages by blending a specific whisker dispersed mixture with diamond powder and metal powder and sintering. CONSTITUTION:60-40 wt.% collected material of secondary aggregate of whisker single fiber of hard material and 40-60 wt.% diamond fine powder as a dispersing and combining auxiliary are added to a dispersion medium such as water or methyl alcohol having high polarity, mechanically stirred, agitated by ultrasonic vibration to give a whisker dispersed mixed solution, from which a dispersion medium is evaporated to give a whisker dispersion mixture. Then 20-5 wt.% mixture is blended with 74-91 wt.% diamond powder and 6-4 wt.% metal powder selected from Co (alloy), a Ni (alloy) and iron (alloy) as a sintering auxiliary to give a raw material for sintering. Then the raw material is heated to >=1,500 deg.C under 57,000 kg/cm<2> so that sintered texture of metal powder is bonded to linked material of diamond particles in gaps in the interior of linked material of diamond particles formed by bonding a great number of fine particles of diamond with particles of diamond by melt of metal powder and the sintered texture of the metal powder is linked to whisker single fibers dispersed into the interior of gaps in the linked material of diamond particles.

Description

[Detailed Description of the Invention] [Industrial Application Field] The whisker composite diamond sintered body of the present invention produced by the production method of the present invention can be used in the same field of application as conventional commercially available diamond sintered bodies. It is the material.

[Conventional technology]

Conventionally manufactured diamond sintered bodies are made by mixing diamond powder with hard additive powder such as titanium carbide and binder powder such as cobalt powder at a rate of 57,000 Kf/c that satisfies the diamond stability conditions. shoulder to 6
The cobalt powder used as a binder is bonded to diamond particles by pressurizing it at a pressure of 0,000 Kq/c and at the same time heating it at a temperature between 1,500 and 1,600 degrees Celsius. It is manufactured by a method in which hard additive particles such as titanium carbide are subjected to liquid phase sintering to produce a diamond sintered body.

[Problems to be solved by the present invention]

As explained in the previous section, in conventionally produced diamond sintered bodies, the sintered bodies are made up of individual diamond particles, individual hard additive particles such as titanium carbide particles, and binders. The cobalt sintered structure of the cobalt powder and the cobalt sintered structure each have a unique expansion coefficient, so each diamond particle, each hard additive particle, and the cobalt sintered structure generate mutually different degrees of expansion. Therefore, the sintered body has built-in strain, and the sintered body has brittleness due to the built-in strain inside the sintered body. . In other words, the diamond sintered body has built-in strain and is brittle, which can cause large and small cracks or large and small chips to occur due to impact when using cutting tools made using the diamond sintered body. The problem to be solved by the present invention is that no method has been developed to suppress the occurrence of cracks or defects due to this cause.

[Means for solving problems]

In the present invention, as a means to solve the problem, a large number of diamond particles as the main material, a large number of hard substance whisker single fibers as a composite material, and a large number of diamond fine particles as a dispersed composite material are provided. A mixture of a large number of particles of metal such as cobalt as a sintering aid is used as a raw material for sintering. In diamond sintered bodies manufactured using such raw materials for sintering, the occurrence of cracks or defects due to brittleness due to internal strain within the sintered body is a problem. The purpose is to solve the problem by exerting a function of suppressing the large number of hard Winnuka single fibers that are internally and dispersed inside the fiber.

To explain further, hard substance whiskers 2 used as a dispersed composite material
Next, the aggregate of the aggregates and the dispersed composite auxiliary material are stirred by mechanical motion and stirred by ultrasonic vibration to produce a whisker-dispersed mixture, and the whisker-dispersed mixture is added to the main material. The raw material for sintering is a mixture obtained by adding powder of a metal such as cobalt as a sintering aid and mixing it with diamond powder. The raw material for sintering thus prepared was 57,000 Kf/
A large number of fine diamond particles and a large number of diamond particles are formed by heating under pressure using a pressure of crI or higher, a temperature of 1,500°C or higher, and a pressure and temperature that satisfy the diamond stability conditions selected. It interacts with the molten metal powder used as a sintering aid to produce a diamond particle bond, and fills the gap with a large number of whisker single fibers dispersed in the gaps of the diamond particle bond. A lineka composite diamond sintered body is produced in which the molten metal powder and the molten metal powder are combined to form a composite sintered body. When performing cutting work using a cutting tool manufactured using the whisker-composite diamond sintered body produced in this manner, internal disturbances may occur in the sintered body forming the cutting tool. The strain is caused by the impact received by the cutting tool.
) When attempting to cause large and small cracks or large and small defects in the cutting tool, many hard materials dispersed and bonded inside the sintered body that constitutes the cutting tool The whiskers suppress the appearance of large and small cracks or large and small defects that would otherwise occur in the cutting tool. That is, by mixing a large number of hard material whiskers with high tensile strength into the raw material for sintering to produce a sintered body for producing a cutting tool, the sintering process can be improved. This is an attempt to solve the problem by suppressing the occurrence of large and small cracks or large and small defects in cutting tools manufactured using the cutting tool.

[For production]

60% to 40% by weight of an aggregate of secondary aggregates of hard whiskers selected as a dispersed composite material from hard whiskers such as silicon carbide whiskers or silicon nitride whiskers having high tensile strength, and a dispersed composite auxiliary material. A mixture of diamond fine powder selected from a ratio range of 40% to 60% by weight is poured into a dispersion of highly polar water or methyl alcohol, etc., and stirred by mechanical motion and super-dispersed. Stirring by sonic vibration is performed to generate a whisker-dispersed mixture, and then the whisker-dispersed mixture is pre-heated with C to vaporize and remove the dispersion to generate a whisker-dispersed mixture. 5% by weight and 74% by weight of diamond powder as the main material.
91% by weight of powder of a metal selected as a sintering aid from cobalt, nickel, iron-cobalt alloy, nickel alloy, iron alloy, 6% to 4% by weight,
A mixture mixed in a ratio selected from within the ratio range is used as a raw material for sintering. Next, the raw material for sintering is heated to a pressure of 57.0OOK9 or more and 1.5
The sintering process is carried out by heating under pressure at a temperature of 00° C. or higher and at a pressure and temperature that satisfy selected diamond stability conditions. In the sintering process, the molten metal powder used as a sintering aid in the sintering raw material melts the individual diamond particles and the surface of each diamond particle, and the surface becomes sintered with the sintering aid metal powder. Individual diamond fine particles and individual diamond particles melted in the melt combine with each other to produce a diamond particle bond, and
A melt of the sintering aid metal powder is liquid-phase sintered on individual whisker single fibers dispersed within the gaps in the diamond particle bond to produce a liquid-phase composite sintered body, and then, Only the heating is stopped while the applied pressure is maintained, and the in-phase composite sintered structure is generated by further cooling.Then, the maintained pressure is returned to normal pressure to produce a whisker composite, which is a composite sintered structure. Produces a diamond sintered body. A whisker composite diamond sintered body consists of individual hard substance whisker single fibers which are a dispersed composite material, individual diamond fine particles which are a dispersed composite auxiliary material, and individual diamond particles which are a main material. Since the sintered structure of the metal powder and the sintered structure of the metal powder, which is a sintering aid, each have a unique coefficient of expansion, strain is inherent in the inside of the whisker composite diamond sintered body.

When performing cutting work using a tool made using a Ricecal composite diamond sintered body that has such internal strain, the internal strain may cause cracks or chips due to the impact of the work. However, the large number of hard whiskers with high tensile strength that are dispersed and bonded inside tools made using whisker composite sintered bodies has the function of suppressing these phenomena. be.

〔Example〕

Example 1゜A mixture was prepared by mixing 50% by weight of silicon carbide liner secondary aggregate aggregates as hard whiskers to be used as a dispersed composite material and 50% by weight of diamond fine powder as a dispersed composite auxiliary material. Pour into highly polar water and stir by mechanical movement and ultrasonic vibration to generate a whisker-dispersed mixture, then heat the whisker-dispersed mixture to vaporize the water and remove the whiskers. A mixture was produced. Then, 5% by weight of the whisker dispersion mixture
The raw material for sintering was a mixture of 90% by weight of diamond powder as the main material and 5% by weight of cobalt powder as a sintering aid. 59,000Kg/i using a high temperature and high pressure generator
A liquid-phase sintered structure is generated by pressurizing the material at a pressure of A solid-phase sintered tissue was produced, and then the pressure that had been maintained was returned to normal pressure, and the resulting composite sintered tissue was taken out. The obtained composite sintered structure is produced by dispersing and acting on the surface of a large number of diamond particles, in which a molten cobalt powder, which is a sintering aid, binds the large number of diamond particles to each other, forming diamond particles. Cobalt powder, which is a sintering aid, is melted into the interstices inside the diamond particle combination and sintered into the diamond combination in a liquid phase. It was a whisker composite diamond sintered body in which molten cobalt was liquid-phase sintered into a large number of internally dispersed silicon carbide whisker single fibers, and then solidified to form a composite sintered structure.

Example 2 A mixture of 40% by weight of aggregates of silicon carbide whisker secondary aggregates as hard substance whiskers to be used as a dispersed composite material and 60% by weight of fine diamond powder as a dispersed composite auxiliary material was prepared. A whisker-dispersed mixture is generated by pouring it into highly polar water and performing mechanical motion (two-way stirring and stirring using ultrasonic vibrations), and then the whisker-dispersed mixture is heated to vaporize the water. Then, the whisker mixture was mixed with 5% by weight and the diamond powder as the main material was mixed with 90% by weight.
A mixture of 5% by weight of sintering aid tosul cobalt powder was used as a raw material for sintering. Next, the raw material for sintering is heated to 61. OO
A liquid phase sintered structure is generated by pressurizing at a pressure of OKg/i and heating at a temperature of 1,650°C at the same time, then stopping only the heating while maintaining the applied pressure, and then applying pressure from the outside. A solid-phase sintered structure was produced by cooling, and then the pressure that had been maintained was returned to normal pressure, and the produced composite sintered structure was taken out. In the obtained composite sintered structure, a molten cobalt powder, which is a sintering aid, is dispersed and acts on the surface of a large number of diamond particles, and the large number of diamond particles are bonded to each other to form a diamond. The particles bond with each other to form a diamond particle bond, and the internal gaps of the diamond particle bond are filled with molten cobalt powder, which is a sintering aid, to form a liquid phase in the diamond particle bond. While being sintered, molten cobalt is sintered in a liquid phase onto a large number of silicon carbide whisker single fibers internally and dispersed in the internal gaps of the diamond particle bond, and then solidified to form a composite sintered structure. It was a whisker composite diamond sintered body.

〔Effect of the invention〕

The whisker composite diamond sintered body of the present invention manufactured by the manufacturing method of the present invention described above is a composite of a large number of diamond particles as a main material, a large number of hard substance whisker single fibers as a dispersed composite material, and a dispersed composite material. A composite sintered structure composed of a large number of fine diamond particles used as an auxiliary material and a sintered structure of a sintering auxiliary metal powder, and the main material constituting the composite sintered structure. A large number of diamond particles, a large number of fine diamond particles that are a dispersed composite material, and a sintered structure of a metal powder that is a sintering aid each have their own specific expansion coefficients. There is built-in strain inside the whisker composite diamond sintered body, which is a composite sintered body made of diamond. During cutting work using a cutting tool made using such a whisker composite diamond composite sintered body, the impact received during the cutting process causes damage to the whisker composite diamond composite sintered body that forms the tool. The applied strain tends to induce large and small cracks or large and small defects, but the large number of hard substance whisker single fibers with high tensile strength that are dispersed and bonded inside the sintered body induce large and small cracks or defects. Since it exhibits the function of suppressing the occurrence of large and small defects, it can significantly increase the effective utilization rate of the tool.

Claims (2)

[Claims] (1) 60% to 40% by weight of an aggregate of secondary aggregates of hard whisker single fibers selected as a dispersed composite material from various types of hard whiskers, and 40% by weight of fine diamond powder as a dispersed composite auxiliary material. A mixture selected from a proportion range of 60% by weight is poured into a highly polar dispersion medium such as water or methyl alcohol, and stirred by mechanical motion and ultrasonic vibration. to produce a whisker-dispersed mixture, then vaporize and remove the dispersion medium from the whisker-dispersed mixture to produce a whisker-dispersed mixture, and add 20% to 5% by weight of the generated whisker-dispersed mixture. 74% to 91% by weight of diamond powder as the main material, and cobalt.
6% by weight of metal powder selected as a sintering aid from nickel, iron, cobalt alloy, nickel alloy, and iron alloy.
A mixture selected from the ratio range of 4% by weight is used as the raw material for sintering, and the raw material for sintering is 57% by weight.
In a sintered body produced by pressurizing and heating using a pressure of ,000Kg/cm^2 or more and a temperature of 1,500℃ or more, a large number of diamond fine particles and diamond particles mutually act as sintering aids. The sintered structure of the metal powder, which is a sintering aid, is bonded to the diamond particle combination in the gap inside the diamond particle combination, which is formed by combining a certain metal powder by the action of the molten body, and the metal powder is sintered. A whisker composite diamond sintered body, characterized in that the connective tissue is bonded to a large number of whisker single fibers dispersed inside the gaps in the diamond particle combination body to form a composite sintered body. . (2) 60% to 40% by weight of an aggregate of secondary aggregates of hard whisker single fibers selected as a dispersed composite material from various types of hard whiskers, and 40% by weight of fine diamond powder as a dispersed composite auxiliary material. A mixture selected from a proportion range of 60% by weight is poured into a highly polar dispersion medium such as water or methyl alcohol, and stirred by mechanical movement and ultrasonic vibration. to produce a whisker-dispersed mixture, then vaporize and remove the dispersion medium from the whisker-dispersed mixture to produce a whisker-dispersed mixture, and add 20% to 5% by weight of the generated whisker-dispersed mixture. 74% to 91% by weight of diamond powder as the main material, and cobalt.
6% by weight of metal powder selected as a sintering aid from nickel, iron, cobalt alloy, nickel alloy, and iron alloy.
A mixture selected from a proportion range of 4% by weight is used as a raw material for sintering, and the raw material for sintering is 57% by weight.
,000Kg/cm^2 or more and at the same time heated at a temperature of 1,500℃ or more, a large number of fine diamond particles and a molten metal powder in which the diamond particles are sintering aids are mutually bonded. The molten metal powder, which is a sintering aid, is sintered in the gap inside the diamond particle combination to form a sintered structure, and at the same time, the diamond particles are combined. Whisker composite diamond sintering is characterized in that a molten metal powder, which is a sintering aid, is combined with a large number of whisker single fibers dispersed in the gaps in the body to produce a composite sintered structure. Method of manufacturing solids.