阅读说明：本技术 聚晶立方氮化硼复合材料及其制备方法、硼化钨作为聚晶立方氮化硼复合材料粘结相的应用 (Polycrystalline cubic boron nitride composite material, preparation method thereof and application of tungsten boride as binding phase of polycrystalline cubic boron nitride composite material ) 是由 莫培程 陈家荣 陈超 于 2021-08-13 设计创作，主要内容包括：本发明提供一种聚晶立方氮化硼复合材料及其制备方法和应用,属于超硬材料技术领域。本发明提供的聚晶立方氮化硼复合材料,包括以下质量份数的制备原料：立方氮化硼60～100份,硼系烧结助剂和碳化钨5～30份,氧化铝和钴粉1～3份；所述硼系烧结助剂为高纯硼粉和/或碳化硼。本发明提供的聚晶立方氮化硼复合材料(PcBN)具有较高的硬度、强度以及优异的耐磨性能。实施例结果表明,本发明制得的PcBN的硬度为36.1～42.5GPa,磨耗比为8420～13700,抗弯强度至少达789.6MPa。(The invention provides a polycrystalline cubic boron nitride composite material and a preparation method and application thereof, belonging to the technical field of superhard materials. The polycrystalline cubic boron nitride composite material provided by the invention comprises the following preparation raw materials in parts by mass: 60-100 parts of cubic boron nitride, 5-30 parts of boron sintering aid and tungsten carbide, and 1-3 parts of alumina and cobalt powder; the boron-based sintering aid is high-purity boron powder and/or boron carbide. The polycrystalline cubic boron nitride composite material (PcBN) provided by the invention has higher hardness and strength and excellent wear resistance. The embodiment results show that the hardness of the PcBN prepared by the invention is 36.1-42.5 GPa, the wear ratio is 8420-13700, and the bending strength is at least 789.6 MPa.)

1. The polycrystalline cubic boron nitride composite material is characterized by comprising the following preparation raw materials in parts by mass:

60-100 parts of cubic boron nitride;

5-30 parts of boron sintering aid and tungsten carbide;

1-3 parts of aluminum oxide and cobalt powder;

the boron-based sintering aid is high-purity boron powder and/or boron carbide.

2. The polycrystalline cubic boron nitride composite material of claim 1, wherein the cubic boron nitride has an average particle size of 1 to 22 μm.

3. The polycrystalline cubic boron nitride composite material of claim 1 wherein the cubic boron nitride comprises a first cubic boron nitride and a second cubic boron nitride; the grain size of the first cubic boron nitride is 1-3 mu m; the grain size of the second cubic boron nitride is 4-8 mu m; the mass ratio of the first cubic boron nitride to the second cubic boron nitride is (8-5) to (2-5).

4. The polycrystalline cubic boron nitride composite material according to claim 1, wherein the average particle sizes of the alumina and the cobalt powder are both 0.5 to 2 μm; the mass ratio of the alumina to the cobalt powder is 1: 1.

5. The polycrystalline cubic boron nitride composite material according to claim 1, wherein the average particle size of the boron-based sintering aid is 0.5 to 3 μm; the average particle size of the high-purity boron powder is 0.5-2 mu m; the average particle size of the boron carbide is 2-3 mu m; the average particle size of the tungsten carbide is 1-5 μm.

6. The polycrystalline cubic boron nitride composite material according to claim 1, wherein when the boron-based sintering aid is high-purity boron powder, the molar ratio of tungsten carbide to the high-purity boron powder is 1-2: 2; when the boron-based sintering aid is boron carbide, the molar ratio of the boron carbide to the tungsten carbide is 1: 2-3.

7. The method of preparing the polycrystalline cubic boron nitride composite material of any one of claims 1 to 6, comprising the steps of:

mixing tungsten carbide, aluminum oxide, a boron sintering aid, cobalt powder and cubic boron nitride to obtain a mixed material;

and sequentially carrying out pre-reaction and sintering on the mixed material to obtain the polycrystalline cubic boron nitride composite material.

8. The preparation method according to claim 7, wherein the sintering pressure is 4-7 GPa, the temperature is 1400-1700 ℃, and the holding time is 5-15 min.

9. The preparation method according to claim 7, wherein the pre-reaction temperature is 800-1200 ℃ and the vacuum degree is 10^-1～10^-3Pa, the time is 1-3 h.

10. The application of the tungsten boride as a bonding phase of the polycrystalline cubic boron nitride composite material is characterized in that the tungsten boride is generated in situ by tungsten carbide and a boron sintering aid; the boron-based sintering aid is the boron-based sintering aid in the raw materials for preparing the polycrystalline cubic boron nitride composite material according to any one of claims 1 to 6.

Technical Field

The invention belongs to the technical field of superhard materials, and particularly relates to a polycrystalline cubic boron nitride composite material, a preparation method thereof, and application of tungsten boride as a binding phase of the polycrystalline cubic boron nitride composite material.

Background

Polycrystalline cubic boron nitride (PcBN) composite materials are polycrystalline bodies which are formed by sintering cubic boron nitride (cBN) micro powder and a bonding agent at high temperature and high pressure. The polycrystalline cubic boron nitride (PcBN) composite material has higher hardness and wear resistance, better heat resistance and chemical inertia than diamond, and is particularly suitable for cutting hardened steel, cast iron, powder metallurgy materials, heat-resistant alloys and other iron-based materials. The binder acts as a bridge to bind the cBN particles, and its presence or absence will directly affect the performance of the PcBN composite.

Conventional ceramic binders commonly used in the art include Al₂O₃TiN and TiC, have good high temperature mechanical properties and thermal conductivity stability, but PcBN made from traditional ceramic binders has problems of poor hardness, strength and wear resistance at room temperature.

Disclosure of Invention

In view of the above, the invention provides a polycrystalline cubic boron nitride composite material, a preparation method thereof and application of tungsten boride as a binding phase of the polycrystalline cubic boron nitride composite material. The polycrystalline cubic boron nitride composite material provided by the invention has higher hardness and strength and excellent wear resistance.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention provides a polycrystalline cubic boron nitride composite material which comprises the following preparation raw materials in parts by mass:

60-100 parts of cubic boron nitride;

5-30 parts of boron sintering aid and tungsten carbide;

1-3 parts of aluminum oxide and cobalt powder;

the boron-based sintering aid is high-purity boron powder and/or boron carbide.

Preferably, the cubic boron nitride has an average particle diameter of 1 to 22 μm.

Preferably, the cubic boron nitride includes a first cubic boron nitride and a second cubic boron nitride; the grain size of the first cubic boron nitride is 1-3 mu m; the grain size of the second cubic boron nitride is 4-8 mu m; the mass ratio of the first cubic boron nitride to the second cubic boron nitride is (8-5) to (2-5).

Preferably, the average grain diameter of the alumina powder and the average grain diameter of the cobalt powder are both 0.5-2 μm; the mass ratio of the alumina to the cobalt powder is 1: 1.

Preferably, the average particle size of the boron-based sintering aid is 0.5 to 3 μm; the average particle size of the high-purity boron powder is 0.5-2 mu m; the average particle size of the boron carbide is 2-3 mu m; the average particle size of the tungsten carbide is 1-5 μm.

Preferably, when the boron-based sintering aid is high-purity boron powder, the molar ratio of tungsten carbide to the high-purity boron powder is 1-2: 2; when the boron-based sintering aid is boron carbide, the molar ratio of the boron carbide to the tungsten carbide is 1: 2-3.

The invention also provides a preparation method of the polycrystalline cubic boron nitride composite material, which comprises the following steps:

mixing tungsten carbide, aluminum oxide, a boron sintering aid, cobalt powder and cubic boron nitride to obtain a mixed material;

and sequentially carrying out pre-reaction and sintering on the mixed material to obtain the polycrystalline cubic boron nitride composite material.

Preferably, the sintering pressure is 4-7 GPa, the temperature is 1400-1700 ℃, and the heat preservation time is 5-15 min.

Preferably, the pre-reaction temperature is 800-1200 ℃, and the vacuum degree is 10^-1～10^-3Pa, the time is 1-3 h.

The invention also provides the application of the tungsten boride as a bonding phase of the polycrystalline cubic boron nitride composite material, wherein the tungsten boride is generated in situ by tungsten carbide and a boron sintering aid; the boron-based sintering aid is the boron-based sintering aid in the raw materials for preparing the polycrystalline cubic boron nitride composite material in the technical scheme.

The polycrystalline cubic boron nitride composite material (PcBN) provided by the invention comprises the following preparation raw materials in parts by mass: 60-100 parts of cubic boron nitride; 5-30 parts of boron sintering aid and tungsten carbide; 1-3 parts of aluminum oxide and cobalt powder; the boron-based sintering aid is high-purity boron powder and/or boron carbide. In the invention, the boron-based sintering aid can react with tungsten carbide to generate tungsten boride with high hardness and excellent wear resistance, and the tungsten boride generated in situ in the system is used as a bonding phase to bond cBN particles, so that the hardness and wear resistance of the polycrystalline cubic boron nitride composite material can be improved; in addition, the method takes the tungsten boride generated in situ as a binding phase to play a role in filling pores, prepares compact-structure PcBN, and enhances the strength of the polycrystalline cubic boron nitride composite material. The embodiment results show that the hardness of the PcBN prepared by the invention is 36.1-42.5 GPa, the wear ratio is 8420-13700, and the bending strength is at least 789.6 MPa.

The invention also provides a preparation method of the polycrystalline cubic boron nitride composite material, which comprises the following steps: mixing tungsten carbide, aluminum oxide, a boron sintering aid, cobalt powder and cubic boron nitride to obtain a mixed material; and sequentially carrying out pre-reaction and sintering on the mixed material to obtain the polycrystalline cubic boron nitride composite material. The preparation method provided by the invention is simple to operate, wide in raw material source and easy for industrial production.

Drawings

FIG. 1 is an SEM photograph of a sample obtained in example 1;

FIG. 2 is an XRD analysis pattern of a sample obtained in example 1.

Detailed Description

The invention provides a polycrystalline cubic boron nitride composite material which comprises the following preparation raw materials in parts by mass:

60-100 parts of cubic boron nitride, 5-30 parts of boron-based sintering aid and tungsten carbide, and 1-3 parts of alumina and cobalt powder, wherein the boron-based sintering aid is high-purity boron powder and/or boron carbide.

In the present invention, the raw materials used are all commercial products conventional in the art unless otherwise specified.

The polycrystalline cubic boron nitride composite material is prepared from 60-100 parts by mass of cubic boron nitride, preferably 70-90 parts by mass of cubic boron nitride, and particularly preferably 70, 75 and 90 parts by mass of the polycrystalline cubic boron nitride composite material in an embodiment of the invention. In the present invention, the average particle size of the cubic boron nitride is preferably 1 to 22 μm, and more preferably 1 to 12 μm. In the present invention, the cubic boron nitride preferably includes a first cubic boron nitride and a second cubic boron nitride; the particle size of the first cubic boron nitride is preferably 1-3 mu m; the grain size of the second cubic boron nitride is preferably 4-8 mu m; the mass ratio of the first cubic boron nitride to the second cubic boron nitride is preferably 8-5: 2-5, and more preferably 7: 3. in the invention, the cubic boron nitride with two granularity sizes is mixed for use, so that the compactness of the sintered block can be improved, and the mechanical property can be improved.

In the invention, the raw materials for preparing the polycrystalline cubic boron nitride composite material comprise, by mass, 5-30 parts of a boron-based sintering aid and tungsten carbide, and more preferably 9-28 parts of cubic boron nitride. In the invention, when the boron-based sintering aid is high-purity boron powder, the molar ratio of the high-purity boron powder to tungsten carbide is preferably 2: 1-2, and more preferably 2: 1-1.2; when the boron-based sintering aid is boron carbide, the molar ratio of boron carbide to tungsten carbide is 1:2 to 3, and more preferably 1:2 to 2.2. In the invention, the average particle size of the boron-based sintering aid is preferably 0.5-3 μm, and when the boron-based sintering aid is high-purity boron powder, the particle size of the high-purity boron powder is preferably 0.5-2 μm; when the boron-based sintering aid is boron carbide, the particle size of the boron carbide is preferably 2 to 3 μm. In the present invention, the average particle size of the tungsten carbide is preferably 1 to 5 μm, more preferably 2 to 5 μm, and most preferably 5 μm. In the invention, the boron-based sintering aid can react with tungsten carbide to generate tungsten boride with high hardness and excellent wear resistance, and the tungsten boride generated in the system is used as a bonding phase to bond cBN particles, so that the hardness and wear resistance of the polycrystalline cubic boron nitride composite material can be improved. Meanwhile, the invention takes tungsten boride generated in the system as a binding phase to play a role in filling pores, prepares compact-structure PcBN, and enhances the strength of the polycrystalline cubic boron nitride composite material.

In the invention, the raw materials for preparing the polycrystalline cubic boron nitride composite material comprise, based on the mass parts of cubic boron nitride, 1-3 parts of alumina and cobalt powder, preferably 1-2 parts, and most preferably 1 part. In the invention, the average particle size of the alumina is preferably 50 to 500nm, more preferably 200 to 500nm, and most preferably 500 nm; the particle size of the cobalt powder is preferably 0.5-2 μm, and more preferably 1 μm. In the present invention, the mass ratio of the alumina to the cobalt powder is preferably 1: 1. in the invention, the alumina and cobalt powder are used as sintering aids, which can accelerate the sintering process, so that the expanded tungsten binding phase is rapidly generated in situ to firmly bind the cubic boron nitride.

In the present invention, the polycrystalline cubic boron nitride composite material is preferably a polycrystalline cubic boron nitride compact.

The invention also provides a preparation method of the polycrystalline cubic boron nitride composite material in the technical scheme, which comprises the following steps:

mixing tungsten carbide, aluminum oxide, a boron sintering aid, cobalt powder and cubic boron nitride to obtain a mixed material;

and sequentially carrying out pre-reaction and sintering on the mixed material to obtain the polycrystalline cubic boron nitride composite material.

The invention mixes tungsten carbide, alumina, boron series sintering auxiliary agent, cobalt powder and cubic boron nitride to obtain mixed material.

In the invention, the mixing mode is preferably wet ball milling, and the mixing medium of the wet ball milling is preferably ethanol; the ball-material ratio of the wet ball milling is preferably 3-5: 1, more preferably 4: 1; the rotation speed of the wet ball milling is preferably 200-300 r/min, and more preferably 250 r/min; the time of the wet ball milling is preferably 1-4 h. In the present invention, the wet ball-milled material is preferably tungsten carbide balls. In the invention, the wet ball milling mixing can make the materials mixed more uniformly.

After the mixing is completed, the invention preferably further comprises drying, crushing and screening the materials obtained after the mixing in sequence.

In the invention, the drying temperature is preferably 80-150 ℃, more preferably 80-100 ℃, and most preferably 80 ℃; the drying time is preferably 6-12 h, more preferably 8-12 h, and most preferably 12 h. The crushing mode is not particularly limited in the present invention, and a crushing mode known to those skilled in the art may be adopted. In the present invention, the average pore diameter of the sieving screen is preferably 100 mesh. In the present invention, after the sieving, the undersize fraction is preferably the target fraction.

After the mixed material is obtained, the mixed material is subjected to pre-reaction and sintering in sequence to obtain the polycrystalline cubic boron nitride composite material.

The pre-reaction is preferably carried out after the mixed material is pressed into a cylinder with the diameter of 14mm and the height of 5mm by a cold press. According to the invention, the mixture is pressed into a cylinder shape and then pre-reacted, so that the pollution of impurities to powder can be reduced.

In the invention, the pre-reaction temperature is preferably 800-1200 ℃, more preferably 900-1100 ℃, and most preferably 1000 ℃; the degree of vacuum is preferably 10^-1～10^-3Pa, more preferably 10^-2Pa, the time is preferably 1-3 h, more preferably 1-2 h, and most preferably 1 h. The specific operation of the pre-reaction is not particularly limited in the present invention, and the conventional pre-reaction operation can be adopted by those skilled in the art. Impurities and moisture in the components are fully removed through pre-reaction, and the purity of powder is ensured, so that the performance of the polycrystalline cubic boron nitride composite material is ensured; in particular in combination with the selected defined pre-reaction conditions, the purity of the material is further increased.

In the invention, the sintering pressure is preferably 4-7 GPa, and more preferably 5.5 GPa; the sintering temperature is preferably 1400-1700 ℃, and further preferably 1500-1650 ℃; the heat preservation time of the sintering is preferably 5-15 min, and more preferably 10 min. In the present invention, sintering is carried out under the above conditions, which is more favorable for the production of tungsten boride. The present invention does not specifically limit the operation of the sintering process, and the sintering process known to those skilled in the art may be used. In an embodiment of the invention, the sintering is preferably carried out in a cubic press.

The invention also provides application of the tungsten boride as a binding phase of the polycrystalline cubic boron nitride composite material, wherein the tungsten boride is generated in situ by tungsten carbide and a boron sintering aid; the boron-based sintering aid is the boron-based sintering aid in the raw materials for preparing the polycrystalline cubic boron nitride composite material in the technical scheme.

The polycrystalline cubic boron nitride composite material and the preparation method thereof, and the application of tungsten boride as a binder phase of polycrystalline cubic boron nitride composite material provided by the present invention are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

Example 1

According to the mass parts, 70 parts of cubic boron nitride micro powder, 2.4 parts of high-purity boron powder, 25.6 parts of tungsten carbide, 1 part of aluminum oxide and 1 part of cobalt powder are prepared.

The cubic boron nitride micro powder consists of two particle sizes which are respectively 1-3 mu m and 4-8 mu m, and the weight ratio of the two particle sizes is 7: 3; the average grain size of the high-purity boron powder is 0.5-2 mu m, and the average grain size of the tungsten carbide is 5 mu m; the average particle size of the alumina was 0.5 μm, and the average particle size of the cobalt powder was 1 μm.

Performing wet ball milling on the prepared material on a ball mill, and adding ethanol as a dispersion medium; then adding tungsten carbide balls, wherein the ball-to-material ratio of wet ball milling is 4:1, the rotating speed is 250r/min, drying for 12h at 80 ℃ after wet ball milling is carried out for 2h, and sieving with a 100-mesh sieve to obtain a mixed material.

The mixed material was pressed into a cylindrical shape having a diameter of 14mm and a height of 5mm by a cold press. Then, the temperature was 1000 ℃ and the degree of vacuum was 10^-2The mixture pressed into a cylinder under the Pa condition is pre-reacted for 1 hour.

And assembling the treated samples according to an assembling mode required by a press.

And sintering the assembled sample in a cubic hinge press to synthesize the polycrystalline cubic boron nitride composite material, wherein the pressure is 5.5GPa, the temperature is 1600 ℃, and the heat preservation time is 10min to obtain the polycrystalline cubic boron nitride composite material.

Example 2

Preparing 90 parts of cubic boron nitride micro powder, 0.9 part of high-purity boron powder, 8.1 parts of tungsten carbide, 0.5 part of aluminum oxide and 0.5 part of cobalt powder.

Wherein the grain size of the cubic boron nitride micro powder is 4-8 μm, the average grain size of the high-purity boron powder is 0.5-2 μm, and the average grain size of the tungsten carbide is 5 μm; the average particle size of the alumina was 0.5 μm, and the average particle size of the cobalt powder was 1 μm.

Performing wet ball milling on the prepared material on a ball mill, and adding ethanol as a dispersion medium; adding tungsten carbide balls, performing wet ball milling at a ball-to-material ratio of 4:1 and a rotation speed of 250r/min for 3h, drying at 80 ℃ for 12h, and sieving with a 100-mesh sieve to obtain a mixed material.

The mixed material was pressed into a cylindrical shape having a diameter of 14mm and a height of 5mm by a cold press. Then, the temperature was 1000 ℃ and the degree of vacuum was 10^-2The mixture pressed into a cylinder under the Pa condition is pre-reacted for 1 hour.

And assembling the treated samples according to an assembling mode required by a press.

And sintering the assembled sample in a cubic hinge press to synthesize the polycrystalline cubic boron nitride composite material, wherein the pressure is 5.5GPa, the temperature is 1650 ℃, and the heat preservation time is 10min to obtain the polycrystalline cubic boron nitride composite material.

Example 3

75 parts of cubic boron nitride micro powder, 2.6 parts of boron carbide, 20.4 parts of tungsten carbide, 1 part of aluminum oxide and 1 part of cobalt powder are prepared.

Wherein the cubic boron nitride micro powder consists of two particle sizes which are respectively 1-3 μm and 4-8 μm, and the weight ratio of the two particle sizes is 7: 3; the average particle size of boron carbide is 2-3 mu m, and the average particle size of tungsten carbide is 5 mu m; the average particle size of the alumina powder was 0.5 μm, and the average particle size of the cobalt powder was 1 μm.

Performing wet ball milling on the prepared material on a ball mill, and adding ethanol as a dispersion medium; adding tungsten carbide balls, performing wet ball milling at a ball-to-material ratio of 4:1 and a rotation speed of 250r/min for 2h, drying at 80 ℃ for 12h, and sieving with a 100-mesh sieve to obtain a mixed material.

The mixed material was pressed into a cylindrical shape having a diameter of 14mm and a height of 5mm by a cold press. Then, the temperature was 1000 ℃ and the degree of vacuum was 10^-2The mixture pressed into a cylinder under the Pa condition is pre-reacted for 1 hour.

And assembling the treated samples according to an assembling mode required by a press.

And sintering the assembled sample in a cubic hinge press to synthesize the polycrystalline cubic boron nitride composite material, wherein the pressure is 5.5GPa, the temperature is 1600 ℃, and the heat preservation time is 10min to obtain the polycrystalline cubic boron nitride composite material.

Example 4

Preparing 90 parts of cubic boron nitride micro powder, 1.1 parts of boron carbide, 7.9 parts of tungsten carbide, 0.5 part of aluminum oxide and 0.5 part of cobalt powder.

Wherein the grain size of the cubic boron nitride micro powder is 4-8 mu m, the average grain size of boron carbide is 2-3 mu m, the average grain size of tungsten carbide powder is 5 mu m, the average grain size of alumina powder is 0.5 mu m, and the average grain size of cobalt powder is 1 mu m.

Performing wet ball milling on the prepared material on a ball mill, and adding ethanol as a dispersion medium; adding tungsten carbide balls, performing wet ball milling at a ball-to-material ratio of 4:1 and a rotation speed of 250r/min for 3h, drying at 80 ℃ for 12h, and sieving with a 100-mesh sieve to obtain a mixed material.

The mixed material was pressed into a cylindrical shape having a diameter of 14mm and a height of 5mm by a cold press. Then, the temperature was 1000 ℃ and the degree of vacuum was 10^-2The mixture pressed into a cylinder under the Pa condition is pre-reacted for 1 hour.

And assembling the treated samples according to an assembling mode required by a press.

And sintering the assembled sample in a cubic hinge press to synthesize the polycrystalline cubic boron nitride composite material, wherein the pressure is 5.5GPa, the temperature is 1650 ℃, and the heat preservation time is 10min to obtain the polycrystalline cubic boron nitride composite material.

Example 5

According to the preparation method described in example 1, the hardness of the sample obtained in example 5 was 36.1GPa, and the wear ratio was 9150, which were obtained by replacing the grain size composition of the cubic boron nitride fine powder with grain sizes of 4 to 8 μm and keeping the other conditions unchanged.

Example 6

According to the preparation method described in example 3, the hardness of the sample obtained in example 6 was 36.7GPa and the wear ratio was 8420, which were obtained by replacing only the grain size composition of the cubic boron nitride fine powder of two grain sizes with a grain size of 4 to 8 μm, and keeping the other conditions.

The test results of example 1 and example 5, and example 3 and example 6 can prove that: the cubic boron nitride with two granularity sizes is mixed for use, so that the compactness of the sintered block can be improved, and the hardness and the abrasion ratio of the sintered block are further facilitated.

SEM tests were performed on the samples obtained in examples 1-6, and the test results of example 1 are shown in FIG. 1: the bonding interface between the cBN particles and the binding phase tungsten boride in the sintered sample is very tight, and the prepared sample is proved to have good compactness. As can be seen from the observation, obvious grain boundaries and smooth crystal faces can be observed in the figure, which indicates that the samples have along-grain fracture. In addition, obvious saw-toothed grains are observed in the sample in the fracture process, which shows that the cBN and the bonding phase tungsten boride have strong interface bonding force and are accompanied with the occurrence of a transgranular fracture phenomenon in the sample, so that the bending strength of the PcBN is obviously improved. In addition, the three-point bending strength test is carried out on the samples obtained in the example 1 and the example 3, the bending strength of the sample obtained in the example 1 is 809.5MPa, and the bending strength of the sample obtained in the example 3 is 789.6 MPa.

XRD analysis of the polycrystalline cubic boron nitride composite materials prepared in examples 1-6 shows WB₂WB and BN phases, the test results of example 1 are shown in fig. 2: the obtained polycrystalline cubic boron nitride composite material contains WB₂And WB, the results demonstrate that the present invention produces a binder phase of tungsten boride during the reaction.

The polycrystalline cubic boron nitride composite materials prepared in the embodiments 1 to 6 are subjected to performance tests, and the test results are shown in table 1; wherein the microhardness and the abrasion ratio of the hardness test are tested according to JB-T3235.

TABLE 1 Performance test results for polycrystalline cubic boron nitride composites prepared in examples 1-6

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Test method
								Hardness (GPa)	37.6	42.1	38.6	42.5	36.1	36.7	Microhardness
Wear ratio	10710	12860	9370	13700	9150	8420	JB-T3235

According to the analysis of the experimental data, the polycrystalline cubic boron nitride composite material provided by the invention has higher strength and hardness and excellent wear resistance.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.