High-impact-toughness cubic boron nitride, synthetic method and application thereof

Abstract

The invention discloses high-impact-toughness cubic boron nitride (cBN). The synthetic raw materials comprise Li3N accelerant powder and high-purity hexagonal boron nitride powder with the weight ratio of 1:9-12. In the high-purity hexagonal boron nitride powder, by the weight ratio, the content of hexagonal boron nitride (hBN) is larger than or equal to 98%, and the content of B2O3 is smaller than or equal to 0.5%. The granularity of the high-purity hexagonal boron nitride powder is 20-30 microns. The granularity of the Li3N accelerant powder is 80-100 microns. The invention further discloses a synthetic method and application of the high-impact-toughness cBN. According to high-impact-toughness cBN crystals synthesized through the method, the granularity is that the Ti value of a 60 / 70 cBN single crystal is 61%-64%, the impact toughness value (Ti) of a 70 / 80 cBN single crystal is 67%-70%, and the Ti value of an 80 / 100 cBN single crystal is 75%-78%. The synthesized cBN single crystals are transparent and complete in crystalline form, the hBN conversion rate is 60-65%, and high industrial production value is achieved. The cBN is good in crystalline form, high in conversion rate and long in service life when being used for rough grinding machining.

Description

technical field

[0001] The invention relates to a synthesis technology belonging to superhard materials, in particular to a cubic boron nitride with high impact toughness and its synthesis method and application. Background technique

[0002] Cubic boron nitride (cBN) is a synthetic superhard material that has not been found in nature. Because cBN has excellent characteristics such as ultra-high hardness, higher oxidation resistance temperature and chemical stability than diamond, and does not react with iron group elements at high temperatures, it can be widely used in ferrous metals as super abrasives, abrasive tools and tool materials. Grinding and cutting processing of materials and their alloys.

[0003] In the prior art, the method for industrial production of synthetic cBN mainly adopts hexagonal boron nitride (hBN) as raw material, and alkali metals Li, Mg, Ca, etc. and their nitrides are synthesized under high temperature and high pressure as catalyst materials (su...

Examples

Embodiment 1

[0038] A preliminary preparation

[0039] 1) Li with a particle size of 80 μm 3 N catalyst powder and hBN content 98% by mass ratio, B 2 o 3 The high-purity hexagonal boron nitride powder with a particle size of 20 μm and a content of 0.5% is weighed at a weight ratio of 1:9, put into a mortar and evenly mixed with a spoon to form a mixed powder;

[0040] 2) Put the hand-mixed powder into an inclined, uniformly rotating mixer for mixing; the time is 4 hours; during the mixing process, attention should be paid to the tightness of the sample, in order to avoid Li 3 N reacts with water in the air, and vacuumizes the mixing tank;

[0041]3), because hBN is a barren raw material, the molding performance is relatively poor; the mixed powder mixed in step 2) is sealed, and isostatically pressed on a frame-type cold isostatic press with a pressure of 120Mpa, and the isostatic pressing molding can Form the barren powder into a compact green body;

[0042] 4) Weigh the powder with ...

Embodiment 2

[0055] A preliminary preparation

[0056] 1) Li with a particle size of 90 μm 3 N catalyst powder and hBN content 99% by mass ratio, B 2 o 3 The high-purity hexagonal boron nitride powder with a particle size of 25 μm and a content of 0.4% is weighed at a weight ratio of 1:10, put into a mortar and evenly mixed with a spoon to form a mixed powder;

[0057] 2) Put the hand-mixed powder into an inclined, uniformly rotating mixer for mixing; the time is 5 hours; during the mixing process, attention should be paid to the tightness of the sample, in order to avoid Li 3 N reacts with water in the air, and vacuumizes the mixing tank;

[0058] 3), because hBN is a barren raw material, the molding performance is relatively poor; the step 2) is mixed uniformly and sealed, and isostatically pressed with a pressure of 130Mpa on a frame-type cold isostatic press, and the isostatically pressed molding can Form the barren powder into a compact green body;

[0059] 4) Weigh the powder wi...

Embodiment 3

[0072] A preliminary preparation

[0073] 1) Li with a particle size of 100 μm 3 N catalyst powder and hBN content 99% by mass ratio, B 2 o 3 The high-purity hexagonal boron nitride powder with a particle size of 0.3% and a particle size of 30 μm is weighed at a weight ratio of 1:11, put into a mortar and mixed evenly with a spoon to form a mixed powder;

[0074] 2) Put the hand-mixed powder into an inclined, uniformly rotating mixer for mixing; the time is 6 hours; during the mixing process, attention should be paid to the tightness of the sample, in order to avoid Li3N from reacting with water in the air , vacuumize the mixing tank;

[0075] 3), because hBN is a barren raw material, the molding performance is relatively poor; the mixed powder mixed in step 2) is sealed, and isostatically pressed on a frame-type cold isostatic press with a pressure of 140Mpa, and the isostatic molding can Form the barren powder into a compact green body;

[0076] 4) Weigh the powder with...

technical field

[0001] The invention relates to a synthesis technology belonging to superhard materials, in particular to a cubic boron nitride with high impact toughness and its synthesis method and application. Background technique

[0002] Cubic boron nitride (cBN) is a synthetic superhard material that has not been found in nature. Because cBN has excellent characteristics such as ultra-high hardness, higher oxidation resistance temperature and chemical stability than diamond, and does not react with iron group elements at high temperatures, it can be widely used in ferrous metals as super abrasives, abrasive tools and tool materials. Grinding and cutting processing of materials and their alloys.

[0003] In the prior art, the method for industrial production of synthetic cBN mainly adopts hexagonal boron nitride (hBN) as raw material, and alkali metals Li, Mg, Ca, etc. and their nitrides are synthesized under high temperature and high pressure as catalyst materials (su...

Examples

Embodiment 1

[0038] A preliminary preparation

[0039] 1) Li with a particle size of 80 μm 3 N catalyst powder and hBN content 98% by mass ratio, B 2 o 3 The high-purity hexagonal boron nitride powder with a particle size of 20 μm and a content of 0.5% is weighed at a weight ratio of 1:9, put into a mortar and evenly mixed with a spoon to form a mixed powder;

[0040] 2) Put the hand-mixed powder into an inclined, uniformly rotating mixer for mixing; the time is 4 hours; during the mixing process, attention should be paid to the tightness of the sample, in order to avoid Li 3 N reacts with water in the air, and vacuumizes the mixing tank;

[0041]3), because hBN is a barren raw material, the molding performance is relatively poor; the mixed powder mixed in step 2) is sealed, and isostatically pressed on a frame-type cold isostatic press with a pressure of 120Mpa, and the isostatic pressing molding can Form the barren powder into a compact green body;

[0042] 4) Weigh the powder with ...

Embodiment 2

[0055] A preliminary preparation

[0056] 1) Li with a particle size of 90 μm 3 N catalyst powder and hBN content 99% by mass ratio, B 2 o 3 The high-purity hexagonal boron nitride powder with a particle size of 25 μm and a content of 0.4% is weighed at a weight ratio of 1:10, put into a mortar and evenly mixed with a spoon to form a mixed powder;

[0057] 2) Put the hand-mixed powder into an inclined, uniformly rotating mixer for mixing; the time is 5 hours; during the mixing process, attention should be paid to the tightness of the sample, in order to avoid Li 3 N reacts with water in the air, and vacuumizes the mixing tank;

[0058] 3), because hBN is a barren raw material, the molding performance is relatively poor; the step 2) is mixed uniformly and sealed, and isostatically pressed with a pressure of 130Mpa on a frame-type cold isostatic press, and the isostatically pressed molding can Form the barren powder into a compact green body;

[0059] 4) Weigh the powder wi...

Embodiment 3

[0072] A preliminary preparation

[0073] 1) Li with a particle size of 100 μm 3 N catalyst powder and hBN content 99% by mass ratio, B 2 o 3 The high-purity hexagonal boron nitride powder with a particle size of 0.3% and a particle size of 30 μm is weighed at a weight ratio of 1:11, put into a mortar and mixed evenly with a spoon to form a mixed powder;

[0074] 2) Put the hand-mixed powder into an inclined, uniformly rotating mixer for mixing; the time is 6 hours; during the mixing process, attention should be paid to the tightness of the sample, in order to avoid Li3N from reacting with water in the air , vacuumize the mixing tank;

[0075] 3), because hBN is a barren raw material, the molding performance is relatively poor; the mixed powder mixed in step 2) is sealed, and isostatically pressed on a frame-type cold isostatic press with a pressure of 140Mpa, and the isostatic molding can Form the barren powder into a compact green body;

[0076] 4) Weigh the powder with...

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