Cubic boron nitride, catalyst for synthesizing cubic boron nitride, and process for producing cubic boron nitride

Abstract

Cubic boron nitride (CBN) is produced with a CBN synthesis catalyst which comprises a CBN synthesis catalyst ingredient and an organic substance with which the surface of the catalyst ingredient has been coated. The amount of the organic substance is preferably 0.01 to 50 parts by weight per 100 parts by weight of the CBN synthesis catalyst ingredient. The organic substance preferably is stearic acid and / or lauric acid. By the use of such CBN synthesis catalyst, CBN which has a sharp shape with a well developed (111) plane and which is reduced in catalyst ingredient inclusion therein can be produced at a high conversion (in high yield) through simple steps and operations with satisfactory productivity.

Description

Technical field

[0001] The present invention relates to cubic boron nitride (hereinafter referred to as CBN) used in grinding wheels, etc., and a CBN synthesis catalyst (also referred to as solvent) used in the production of CBN from hexagonal boron nitride (hereinafter referred to as HBN), and the use of The CBN manufacturing method of the CBN synthesis catalyst is described. Background technique

[0002] CBN has a hardness second only to diamond and has a chemical stability that exceeds that of diamond, and its demand for abrasive grains for grinding, polishing, and cutting materials is increasing. Various methods for the manufacture of cubic boron nitride have been proposed. Among them, the most widely known and widely used method in industry is to maintain HBN at about 4 to 6 GPa and about 1400 to 1600°C in the presence of a CBN synthesis catalyst. A method of converting hexagonal boron nitride into cubic boron nitride in the thermodynamically stable region of cubic boron nit...

Examples

Embodiment 1～21

[0088] The various catalysts described in Table 1 were pulverized to 50 μm or less using a vibration mill in a glove box of dried nitrogen flow. In the combination and ratio shown in Table 1, the catalyst powder taken out from the pulverizing container was mixed with the organic substance in the liquid state using a sealed mixer to form an organic substance layer on the surface of the catalyst. When using solid organics at normal temperature, heat the mixing container from the outside so that the organics can maintain a liquid state during the mixing process.

[0089] Relative to 10 parts by mass of raw material HBN powder (UHP-1 manufactured by Showa Denko (TM) Grade), mix and mix the CBN synthesis catalyst with the ratio shown in Table 1, so that the mixed powder becomes 1.85g / cm 3 The molding density is the same.

[0090] Then, the molded body was stored in a reaction vessel and treated at 1450° C. and 5.0 GPa for 10 minutes under high temperature and high pressure conditions, ...

Embodiment 22～25、 comparative example 11～18

[0106] The CBN of the Examples and Comparative Examples described in Table 5 was classified into a particle size of 140 / 170 as described in JIS B 4130: 1998 "Diamond / CBN Tool-Diamond or CBN and (Abrasive) Grain Size". The so-called 140 / 170 of the particle size described in JIS B 4130: 1998 means that when four electro-engraved sieves with meshes of 165 μm, 116 μm, 90 μm, and 65 μm are used, the particle size is adjusted so that 99.9% or more passes through the sieve The first sieve with a hole of 165μm, the remaining amount on the second sieve with a sieve opening of 116μm is less than 11%, and the remaining 85% or more on the third sieve with a sieve opening of 90μm, passing the same 90μm The amount of the sieve is 11% or less, and the amount that passes through the fourth sieve with a mesh opening of 65 μm is less than 2%. Then, for the CBN whose particle size was adjusted to 140 / 170, as one of the indicators of the strength of the CBN, the toughness value, which is an indicator...

Embodiment 26、 comparative example 19

[0111] The CBN of Example 20 and Comparative Example 3 were classified into a particle size of 140 / 170 as described in JIS B 4130: 1998, and used to form grinding wheel segments. A mixture of CBN, a borosilicate glassy bonding material as a bonding agent, and a binder (phenolic resin) is prepared, press-molded at 150°C, and then fired at 1100°C (atmospheric atmosphere). The binder used burns when the grinding wheel is fired to form pores. The mixing ratio was 50% by volume of abrasive grains, 20% by volume of binder, 10% by volume of binder, and 30% by volume of porosity after firing. After the thus-obtained grinding wheel segments were bonded to aluminum base metal for grinding wheel formation, a grinding test was performed under the following grinding conditions. The grinding results are shown in Table 6.

[0112] Grinding wheel 1A1 shape, 150D×5U×3X×76.2H

[0113] Grinding disc Horizontal axis surface grinding disc (grinding wheel shaft engine 3.7kW)

[0114] Material to be gro...

Technical field

[0001] The present invention relates to cubic boron nitride (hereinafter referred to as CBN) used in grinding wheels, etc., and a CBN synthesis catalyst (also referred to as solvent) used in the production of CBN from hexagonal boron nitride (hereinafter referred to as HBN), and the use of The CBN manufacturing method of the CBN synthesis catalyst is described. Background technique

[0002] CBN has a hardness second only to diamond and has a chemical stability that exceeds that of diamond, and its demand for abrasive grains for grinding, polishing, and cutting materials is increasing. Various methods for the manufacture of cubic boron nitride have been proposed. Among them, the most widely known and widely used method in industry is to maintain HBN at about 4 to 6 GPa and about 1400 to 1600°C in the presence of a CBN synthesis catalyst. A method of converting hexagonal boron nitride into cubic boron nitride in the thermodynamically stable region of cubic boron nit...

Examples

Embodiment 1～21

[0088] The various catalysts described in Table 1 were pulverized to 50 μm or less using a vibration mill in a glove box of dried nitrogen flow. In the combination and ratio shown in Table 1, the catalyst powder taken out from the pulverizing container was mixed with the organic substance in the liquid state using a sealed mixer to form an organic substance layer on the surface of the catalyst. When using solid organics at normal temperature, heat the mixing container from the outside so that the organics can maintain a liquid state during the mixing process.

[0089] Relative to 10 parts by mass of raw material HBN powder (UHP-1 manufactured by Showa Denko (TM) Grade), mix and mix the CBN synthesis catalyst with the ratio shown in Table 1, so that the mixed powder becomes 1.85g / cm 3 The molding density is the same.

[0090] Then, the molded body was stored in a reaction vessel and treated at 1450° C. and 5.0 GPa for 10 minutes under high temperature and high pressure conditions, ...

Embodiment 22～25、 comparative example 11～18

[0106] The CBN of the Examples and Comparative Examples described in Table 5 was classified into a particle size of 140 / 170 as described in JIS B 4130: 1998 "Diamond / CBN Tool-Diamond or CBN and (Abrasive) Grain Size". The so-called 140 / 170 of the particle size described in JIS B 4130: 1998 means that when four electro-engraved sieves with meshes of 165 μm, 116 μm, 90 μm, and 65 μm are used, the particle size is adjusted so that 99.9% or more passes through the sieve The first sieve with a hole of 165μm, the remaining amount on the second sieve with a sieve opening of 116μm is less than 11%, and the remaining 85% or more on the third sieve with a sieve opening of 90μm, passing the same 90μm The amount of the sieve is 11% or less, and the amount that passes through the fourth sieve with a mesh opening of 65 μm is less than 2%. Then, for the CBN whose particle size was adjusted to 140 / 170, as one of the indicators of the strength of the CBN, the toughness value, which is an indicator...

Embodiment 26、 comparative example 19

[0111] The CBN of Example 20 and Comparative Example 3 were classified into a particle size of 140 / 170 as described in JIS B 4130: 1998, and used to form grinding wheel segments. A mixture of CBN, a borosilicate glassy bonding material as a bonding agent, and a binder (phenolic resin) is prepared, press-molded at 150°C, and then fired at 1100°C (atmospheric atmosphere). The binder used burns when the grinding wheel is fired to form pores. The mixing ratio was 50% by volume of abrasive grains, 20% by volume of binder, 10% by volume of binder, and 30% by volume of porosity after firing. After the thus-obtained grinding wheel segments were bonded to aluminum base metal for grinding wheel formation, a grinding test was performed under the following grinding conditions. The grinding results are shown in Table 6.

[0112] Grinding wheel 1A1 shape, 150D×5U×3X×76.2H

[0113] Grinding disc Horizontal axis surface grinding disc (grinding wheel shaft engine 3.7kW)

[0114] Material to be gro...