JPS5812322B2 - Manufacturing method of cubic boron nitride solids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a cubic boron nitride solid for use as a hard tool material.

In the raw materials used in manufacturing cubic boron nitride solids used as hard tool materials, the present invention includes cubic boron nitride powder as a hard main material and silicon nitride powder as a hard sub-material. The added mixed powder is used as a hard material, and the mixed powder used as the hard material is sintered.
The present invention is characterized in that a mixed powder of magnesium powder and silicon powder or a powder of an alloy of magnesium and silicon is used as a binding material for sintering and bonding.

As described above, the present invention provides a mixed powder of cubic boron nitride powder as a hard main material and silicon nitride powder as a hard sub-material, and a mixed powder of magnesium powder and silicon powder or a combination of magnesium and silicon powder. A mixture containing alloy powder as a binder is used as a raw material, and the raw material prepared in this way is used for sintering, which is necessary to satisfy the stable temperature and pressure conditions of cubic boron nitride and at the same time perform liquid phase sintering. The object of the present invention is to provide an industrially effective method for producing cubic boron nitride solids for use as hard tool materials by sintering them at high temperatures and sintering pressures.

Next, the process and operation of manufacturing a cubic boron nitride solid body to be used as a hard tool material by the method of the present invention will be explained.

The raw materials for producing cubic boron nitride solids that can be used as hard tool materials include cubic boron nitride powder in an amount of 40% to 80% by weight, silicon nitride powder in an amount of 35% to 10% by weight, and magnesium powder. Magnesium-silicon mixed powder mixed in a ratio selected from within the ratio range of 12 weight ratio to 65 weight ratio and silicon powder 88 weight ratio to 35 weight ratio, or a magnesium silicon alloy capable of forming a composition in the selected ratio. A mixture of 25 parts by weight * 10 parts by weight of powder is mixed in a ratio selected from within the ratio range.

The raw material prepared in this manner is filled into a container, and the container is loaded into a high temperature and high pressure generation chamber in a high temperature and high pressure generation device.

Next, the work of sintering the raw materials in the container loaded into the high-temperature, high-pressure generating chamber is carried out at the sintering temperature and sintering temperature necessary to satisfy the stable temperature and pressure conditions for cubic boron nitride, and at the same time to perform liquid phase sintering. pressure and temperature within the range of 1,400℃ to 1,600℃ and 43,000kg/im2 to 55,000k
g/cy2, and then applying the selected sintering pressure to the sintering raw material filled in the container,
Next, the raw material for sintering with the sintering pressure applied is gradually heated to the selected sintering temperature.
The heating necessary to maintain the sintering temperature is maintained for 20 to 60 minutes.

Under this sintering temperature and sintering pressure, for 20 minutes to 60 minutes.
In the sintering raw material exposed for 0 minutes, magnesium and silicon were present in the gaps between the individual particles in the aggregate formed by mixing a large number of cubic boron nitride particles and a large number of boron nitride particles. melts to produce a spongy alloy melt structure, and the spongy alloy melt structure produces a state in which individual cubic boron nitride particles and individual silicon nitride particles are liquid-phase sintered. do.

Next, only the heating is stopped while maintaining the applied sintering pressure, and the high temperature/high pressure generation chamber is further cooled to lower the temperature in the chamber to 300°C.

As a result of the cooling operation under this sintering pressure, the molten alloy structure that had formed a spongy shape and filled the gaps between the individual particles solidified, producing an alloy structure with a spongy structure. The resulting spongy alloy structure sinters and bonds individual cubic boron nitride particles and individual boron nitride particles to produce a solid-phase sintered state.

Next, the main sintering pressure that had been maintained was returned to normal pressure,
The container is pushed out from inside the high temperature and high pressure generation chamber, and the sintered body is taken out from inside the container.

The obtained sintered body contains an alloy structure with a spongy structure made of a magnesium silicon alloy between individual particles in an aggregate of a large number of cubic boron nitride particles and a large number of silicon nitride particles. comprising a binder region that is
The alloy structure having a spongy structure made of a magnesium silicon alloy, which is the binder region, is a composite of individual cubic boron nitride particles in an aggregate in which a large number of cubic boron nitride particles and a large number of silicon nitride particles are mixed. And by combining individual silicon nitride particles! There are seven cubic boron nitride solids that can be used as hard tool materials.

Next, a method for producing a cubic boron nitride solid body used as a hard tool material by the method of the present invention will be described with reference to examples.

Example 1 The raw materials include magnesium silicon having a composition of 50 parts by weight of cubic boron nitride powder, 25 parts by weight of silicon nitride powder, 20 parts by weight of magnesium and 80 parts by weight of silicon. A mixture was used in which alloy powder was mixed at a ratio of 25% by weight.

The raw material prepared in this manner was filled into a container, and the container was loaded into a high temperature and high pressure generation chamber of a high temperature and high pressure generation device.

Next, a temperature of 1,500°C and a pressure of 50,000 kg/cr2 were selected as the sintering temperature and pressure used in the operation of sintering the raw materials filled in the container.

Next, a selected sintering pressure of 50,00oky/crt was applied to the sintering raw material in the container loaded into the high temperature and high pressure generating chamber.

Next, the raw material for sintering with the sintering pressure applied was gradually heated to a selected sintering temperature of 1,500°C, and the sintering temperature was increased to 1,500°C. The heating required to maintain 500C was maintained for 55 minutes.

Next, while maintaining the main sintering pressure,
Only the heating was stopped, and the high temperature and high pressure generation chamber was water cooled from the outside.

After the temperature in the chamber fell to 300° C., the main sintering pressure that had been applied was returned to Josho.

Next, the container was pushed inside the high temperature and high pressure generating chamber, and the sintered body was taken out from inside the container.

The obtained sintered body has an alloy structure with a spongy structure made of a magnesium-silicon alloy between the individual particles in an aggregate in which a large number of cubic boron nitride particles and a large number of silicon nitride particles are mixed. It is the body.

A spongy-structured alloy structure made of a magnesium-silicon alloy, which is a binder region, is an aggregate of a large number of cubic boron nitride particles and a large number of silicon nitride particles. This is a cubic boron nitride solid that can be used as a hard tool material and is made by combining individual cubic boron nitride particles and individual silicon nitride particles.

Example 2 The raw materials include 60 parts by weight of cubic boron nitride powder, 20 parts by weight of silicon nitride powder, 20 parts by weight of magnesium silicon mixed powder with a ratio of 24 parts by weight of magnesium powder and 76 parts by weight of silicon powder. A mixture was used which was mixed in the proportions of .

The raw material prepared in this manner was filled into a container, and the container was loaded into a high temperature and high pressure generating chamber.

Next, the work of sintering the raw materials in the container loaded into the high temperature and high pressure generating chamber was carried out in the same manner as in Example 1.

Similar to the sintered body obtained in Example 1, the sintered body obtained after the sintering process is a mixture of a large number of cubic boron nitride particles and a large number of silicon nitride particles. The bonding material region is a spongy-structured alloy tissue made of a magnesium-silicon alloy between individual particles in the body, and the binder region is a spongy-structured alloy tissue made of a magnesium-silicon alloy. However, it can be used as a hard tool material made by combining individual cubic boron nitride particles and individual silicon nitride particles in a mixed aggregate of many cubic boron nitride particles and many silicon nitride particles. It was a cubic boron nitride solid.

Example 3 Raw materials include cubic boron nitride powder in a proportion of 70 parts by weight, silicon nitride powder in a proportion of 15 parts by weight, magnesium powder in a ratio of 37 parts by weight and silicon powder in a ratio of 15 parts by weight. A mixture was used which was mixed in the proportions of .

The raw material prepared in this manner was filled into a container, and the container was loaded into a high temperature and high pressure generation chamber.

Next, the work of sintering the raw materials in the container loaded into the high temperature and high pressure generating chamber was carried out in the same manner as in Example 1.

Similar to the sintered body obtained in Example 1, the sintered body obtained after the sintering process is a mixture of a large number of cubic boron nitride particles and a large number of silicon nitride particles. The bonding material region is a spongy-structured alloy tissue made of a magnesium-silicon alloy between individual particles in the body, and the binder region is a spongy-structured alloy tissue made of a magnesium-silicon alloy. However, a cubic boron nitride particle that can be used as a hard tool material is made by combining individual cubic boron nitride particles and individual silicon nitride particles in an aggregate in which a large number of cubic boron nitride particles and a large number of silicon nitride particles are mixed. It was a crystalline boron nitride solid.

Cutting work was carried out using a tip made of a cubic boron nitride solid body manufactured in the example described above and a tip made of a tungsten carbide sintered body made by sintering tungsten carbide powder with cobalt. The actual results were as follows.

If a tip made of sintered tungsten carbide is used to cut a ring-shaped body formed and hardened from chrome tool steel into an outer ring for a roller bearing with an outer diameter of 52 mm and a width of 15 mm, only one polishing is required. In contrast, when using a tip made of cubic boron nitride solids, it was possible to cut 1,720 to 1,760 pieces in a row in one polishing. Ta.

As is clear from this cutting experiment, compared to chips made of sintered tungsten carbide, chips made of cubic boron nitride solids were able to achieve significantly higher productivity.

Claims (1)

[Claims] 1 Cubic boron nitride powder is 40 to 80 weight, silicon nitride powder is 35 to 10, magnesium powder is 12 to 65, and silicon powder is 8.
8% by weight to 35% by weight of a magnesium-silicon mixed powder or a magnesium-silicon alloy powder capable of forming a composition of the selected proportion to a proportion range of 25% by weight to 10% by weight. A cubic crystal is produced by using a mixture mixed in a proportion selected from the above as raw materials, filling the raw materials into a container, loading the container into a high temperature and high pressure generating chamber, and then sintering the raw materials filled in the container. The sintering temperature and sintering pressure necessary to satisfy the stable temperature and pressure conditions for boron nitride and at the same time perform liquid phase sintering are set at 1,400°C to 1,400°C.
The sintering material was selected based on the temperature within the range of 600°C and the pressure within the range of 43,000 kg/crl to 55,000 kg/air, and then the material for sintering was selected as the raw material for sintering in the container loaded into the high temperature and high pressure generation chamber. Then, the sintering material under the sintering pressure is gradually heated to the predetermined sintering temperature, and then the sintering material is heated to the predetermined sintering temperature. The heating necessary to maintain the temperature is maintained for 20 to 60 minutes, then only the heating is stopped while maintaining the applied sintering pressure, the high temperature and high pressure generation chamber is further cooled, and then the high temperature and high pressure generation chamber is cooled. A cubic boron nitride solid body, characterized in that after the temperature in the chamber drops to 300°C, the main sintering pressure maintained is returned to normal pressure and the sintered body is taken out from the high temperature and high pressure generation chamber. manufacturing method.