High-performance nano hard alloy, preparation method and application of high-performance nano hard alloy to milling cutter

Abstract

The invention provides a high-performance nano hard alloy, a preparation method and application of the high-performance nano hard alloy to a milling cutter, and the high-performance nano hard alloy comprises the following components in parts by weight: 90.5-98.5 parts of WC powder, 3-6 parts of tungsten powder, 1-3 parts of nano nickel powder, 0.3-0.7 part of bismuth trioxide, 0.5-1.5 parts of chromium boride and 0.6-1.2 parts of rare earth metal powder. The rare earth metal powder comprises lanthanum, cerium, yttrium and rubidium, and the mass ratio of lanthanum to cerium to yttrium to rubidium is 1: (1.2-1.5): (0.8-1.2): (0.4-0.8); the particle size of the WC powder ranges from 0.3 nm to 0.8 nm; the prepared hard alloy has excellent toughness, hardness, bending strength and the like at the same time, and can be better applied to milling cutter manufacturing.

Description

Technical Field

[0001] The invention belongs to the technical field of cemented carbide, and specifically relates to a high-performance nano cemented carbide, a preparation method and an application thereof in a milling cutter. Background Art

[0002] Cemented carbide is a composite material composed of tungsten carbide (WC) and other metals (such as cobalt, nickel, chromium, etc.). It has extremely high hardness, wear resistance and heat resistance, and is widely used in cutting tools, wear-resistant parts, mining equipment, mold manufacturing and other fields. The excellent properties of cemented carbide make it an indispensable key material in modern industry.

[0003] As a key parameter of cemented carbide, carbon content plays a vital role in its performance. Carbon content can directly affect the hardness and wear resistance of cemented carbide products. The presence of carbon can refine the hard phase and enhance the bonding force between hard particles, thereby improving the wear resistance of the alloy. Traditional WC-Co cemented carbide has deficiencies in high temperature strength, fatigue resistance, and crack resistance during processing.

[0004] In the study, in order to improve hardness, toughness and strength at the same time, by adopting the method of fine grain strengthening and solid solution strengthening, compared with conventional grain WC-Co alloy materials, low cobalt (≤6wt% Co) ultrafine grains have higher hardness, strength and wear resistance and other comprehensive mechanical properties. This type of alloy has a WC grain size of 0.3-0.5μm, WC powder is very fine, the specific surface area is large, and the cobalt content is low. The carbon interval of the two-phase region is very narrow. If the industrial production process is not properly controlled, it is very easy to oxidize, decarburize, carburize, uneven dispersion and abnormal grain growth, resulting in unstable product quality and ultimately affecting product performance. Therefore, it is of practical significance to develop a nano-hard alloy with good toughness, hardness and bending strength and other high performance. Summary of the invention

[0005] The purpose of the present invention is to provide a high-performance nano cemented carbide, a preparation method and its application in milling cutters. By taking homemade characteristic WC powder as the main body and under the action of ingredients such as tungsten powder, nickel powder, bismuth trioxide, chromium boride and rare earth metal powder, the prepared cemented carbide has excellent toughness, hardness and bending strength and other properties, and can be better used in milling cutter production.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A high-performance nano-hard alloy comprises the following components by weight: 90.5-98.2 parts of WC powder, 3-6 parts of tungsten powder, 1-3 parts of nano-nickel powder, 0.3-0.7 parts of bismuth trioxide, 0.5-1.5 parts of chromium boride and 0.6-1.2 parts of rare earth metal powder.

[0008] Preferably, the rare earth metal powder comprises lanthanum, cerium, yttrium and rubidium, and the mass ratio is 1:1.2 - 1.5:0.8 - 1.2:0.4 - 0.8.

[0009] Preferably, the particle size of the WC powder is 0.3 - 0.8 nm; the particle size of the tungsten powder is 40 - 60 nm; the particle size of the nickel powder is 2 - 6 nm; the particle size of the bismuth trioxide is 3 - 7 nm; the particle size of the chromium boride is 1 - 4 nm; the particle size of the rare earth metal is 50 - 70 nm.

[0010] A preparation method of a high-performance nano cemented carbide, comprising the following steps:

[0011] S1; Weigh 90.5 - 98.5 parts of WC powder, 3 - 6 parts of tungsten powder, 1 - 3 parts of nano nickel powder, 0.3 - 0.7 parts of bismuth trioxide, 0.5 - 1.5 parts of chromium boride and 0.6 - 1.2 parts of rare earth metal powder and mix to obtain a mixture.

[0012] S2: Put the mixture obtained in step S1 into a ball mill, and then add a ball milling medium to carry out ball milling treatment; after drying and pressing into shape, a green compact is obtained.

[0013] S3: Sinter the green compact obtained in step S2 in a sintering furnace to obtain the cemented carbide.

[0014] Preferably, the preparation process of the WC powder in step S1 is as follows: According to the mass ratio of WC:V:Cr in the WC powder being 95 - 99:0.2 - 0.5:0.3 - 0.6, take ammonium metatungstate, vanadium oxalate, and chromium acetate, and dissolve ammonium metatungstate, vanadium oxalate, and chromium acetate in deionized water according to the solid-liquid ratio of 1 g:10 - 15 ml to obtain a precursor; control the calcination temperature at 650 - 750 °C, the calcination time at 1.5 - 2.5 h, the hydrogen flow rate at 3 - 5 L / min, the carbonization temperature at 1350 - 1500 °C, and the carbonization time at 1 - 3 h. After calcining the precursor, carry out hydrogen reduction carbonization to obtain the WC powder.

[0015] Preferably, the ball-to-material ratio in step S2 is 7 - 12:1; the ball milling medium is alcohol; ball mill at a rate of 350 - 450 r / min for 10 - 14 h.

[0016] Preferably, 1 - 4 parts of sodium hexametaphosphate are further included in step S2.

[0017] Preferably, the pressing pressure in step S2 is 40 - 60 Mpa, and press for 3 - 6 min; the molding agent is PEG 1000 or paraffin.

[0018] Preferably, the sintering temperature in step S3 is 1450 - 1550 °C, and sinter for 1 - 3 h.

[0019] When ordinary nickel powder is used instead of the modified nano-nickel powder, the stability of the product deteriorates most significantly. Secondly, when WC powder is directly commercially available, the change in the performance stability of the product is relatively obvious. When the product raw materials of the present invention are used, the performance stability of the product is the most significant.

[0020] The nano-nickel powder is also subjected to a modification treatment. The specific modification method is as follows:

[0021] S11: Blend 2-5 parts of hexagonal boron nitride nanosheets, 2-3 parts of fullerene powder, and 3-4 parts of carbon nanotubes and add them to 5-8 parts of a 5% sodium silicate solution by mass fraction and stir well to obtain hexagonal boron nitride nanosheet tablets;

[0022] S12: Subsequently, blend 1-2 parts of silane coupling agent KH550, 2-4 parts of TiC, 3-5 parts of hexagonal boron nitride nanosheet tablets, and 5-8 parts of an 8% hydrochloric acid dopamine solution by mass fraction and mix well to obtain a modification liquid;

[0023] S13: First irradiate the nano-nickel powder in a proton irradiation chamber for 10-15 min with an irradiation power of 350 W. After the irradiation ends, add the irradiated nano-nickel powder to the modification liquid according to a weight ratio of 2:5 and stir for modification treatment, then filter and dry. The average particle size of the hexagonal boron nitride nanosheets is 100 nm, the stirring speed for the stirring modification treatment is 450-500 r / min, and stir for 1 h.

[0024] The inventors of the present invention found that when the hexagonal boron nitride nanosheet tablets are not added to the modification liquid, the performance of the product deteriorates more significantly. Secondly, when hexagonal boron nitride nanosheets are not added in the preparation of the hexagonal boron nitride nanosheet tablets, fullerene powder and carbon nanotubes are not added in the preparation of the hexagonal boron nitride nanosheet tablets, and silane coupling agent KH550 and TiC are not added to the modification liquid, the performance of the product all shows a trend of deterioration to varying degrees. Only when the modification liquid obtained by the specific method of the present invention is used, the performance effect of the product is the most significant, and using other methods to replace it is not as obvious as the effect of the present invention.

[0025] The application of the cemented carbide prepared by any one of the above in a milling cutter.

[0026] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0027] In the present invention, ammonium metatungstate, vanadium oxalate, and chromium acetate are calcined and then reduced and carbonized with hydrogen. By precisely controlling the ratio of ammonium metatungstate, vanadium oxalate, and chromium acetate, the contents of W, V, and Cr in the final WC powder can be adjusted, so as to obtain WC powder with specific sizes and physical and chemical properties such as hardness, wear resistance, and corrosion resistance. Meanwhile, tungsten powder, nickel powder, bismuth trioxide, chromium boride, rare earth metal powder, etc. with corresponding particle sizes are combined. During the sintering stage, catalytic sintering densification and mutual penetration and solid solution between alloy materials occur, refining the grain structure in the cemented carbide, making the prepared ultrafine cemented carbide uniform, free of thick inclusions, and void-free; it can effectively improve the toughness and impact resistance of the cemented carbide, improve the processing performance of the cemented carbide, make it easier to form and cut, and improve the oxidation resistance of the cemented carbide, especially when working in a high-temperature environment, so as to enhance the hardness, toughness, flexural strength, etc. of the cemented carbide. At the same time, the nano-nickel powder is improved through a specific process. A modified solution is co-adjusted with hexagonal boron nitride nanosheets, fullerene powder, carbon nanotubes, and a sodium silicate solution with a mass fraction of 5%, as well as through a silane coupling agent KH550, TiC, and a dopamine hydrochloride solution with a mass fraction of 8%. The nano-nickel powder is optimized and improved with the specific modified solution, so that the nano-nickel powder can better cooperate with the self-made nano-nickel powder in the system, optimize the performance coordination of the product, and at the same time, the improvement of the performance stability of the product under harsh conditions such as corrosion, scratching, and high temperature is remarkable. When it is applied to the production of milling cutters, it has high hardness, high toughness, and high strength, and a longer service life. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1

[0030] This example provides a method for preparing a high-performance nano-cemented carbide, including the following steps:

[0031] S1; According to the mass ratio of W:V:Cr of 95:0.2:0.3, take ammonium metatungstate, vanadium oxalate, and chromium acetate. According to the solid-liquid ratio of 1 g:10 ml, dissolve ammonium metatungstate, vanadium oxalate, and chromium acetate in deionized water, and obtain a precursor after drying; control the calcination temperature at 650 °C, the calcination time at 1.5 h, the hydrogen flow rate at 3 L / min, the carbonization temperature at 1350 °C, and the carbonization time at 1 h. After calcining the precursor, perform hydrogen reduction and carbonization to obtain the WC powder;

[0032] Lanthanum, cerium, yttrium and rubidium were mixed in a mass ratio of 1:1.2:0.8:0.4, and stirred at a rate of 200 r / min until uniform to obtain rare earth metal powder;

[0033] Weigh 90.5 g of WC powder, 3 g of tungsten powder, 1 g of nano nickel powder, 0.3 g of bismuth trioxide, 0.5 g of chromium boride and 0.6 g of rare earth metal powder and mix them to obtain a mixed material;

[0034] S2: according to the ball-to-material ratio of 7:1, the mixed material obtained in step S1 was put into a ball mill, and then alcohol was added thereto for ball milling at a rate of 350r / min for 10h; dried at 85°C for 40min; then 0.5g PEG 1000 was added, and the mixture was pressed at a pressure of 40Mpa for 3min to obtain a compact;

[0035] S3: The compact obtained in step S2 is heated to 1450° C. at a rate of 5° C. / min in a sintering furnace, and sintered for 1 hour at this temperature. After cooling, a cemented carbide can be obtained.

[0036] The nano nickel powder is also modified, and the specific modification method is:

[0037] S11: adding 2 parts of hexagonal boron nitride nanosheets, 2 parts of fullerene powder and 3 parts of carbon nanotubes to 5 parts of 5% by mass sodium silicate solution and stirring thoroughly to obtain hexagonal boron nitride nanosheets;

[0038] S12: Then, 1 part of silane coupling agent KH550, 2 parts of TiC, 3 parts of hexagonal boron nitride nano-tablets and 5 parts of 8% by mass dopamine hydrochloride solution are fully mixed to obtain a modified solution;

[0039] S13: irradiate the nano nickel powder in a proton irradiation box for 10 minutes at an irradiation power of 350 W. After the irradiation is completed, add the irradiated nano nickel powder into the modification liquid at a weight ratio of 2:5, stir and modify it, filter and dry it. The average particle size of the hexagonal boron nitride nanosheets is 100 nm. The stirring speed of the stirring modification treatment is 450 r / min, and the stirring is for 1 hour.

[0040] Example 2

[0041] This embodiment provides a method for preparing high-performance nano-cemented carbide, comprising the following steps:

[0042] S1; according to the mass ratio of W:V:Cr being 99:0.5:0.6, ammonium metatungstate, vanadium oxalate and chromium acetate are taken, and the ammonium metatungstate, vanadium oxalate and chromium acetate are dissolved in deionized water according to the solid-liquid ratio of 1g:15ml, and dried to obtain a precursor; the calcination temperature is controlled to be 750°C, the calcination time is 2.5h, the hydrogen flow rate is 5L / min, the carbonization temperature is 1500°C, and the carbonization time is 3h, and the precursor is calcined and then reduced and carbonized by hydrogen to obtain the WC powder;

[0043] Lanthanum, cerium, yttrium and rubidium were mixed in a mass ratio of 1:1.5:1.2:0.8, and stirred at a rate of 300 r / min until uniform to obtain rare earth metal powder;

[0044] Weigh 98.5 g of WC powder, 6 g of tungsten powder, 3 g of nano nickel powder, 0.7 g of bismuth trioxide, 1.5 g of chromium boride and 1.2 g of rare earth metal powder and mix them to obtain a mixture;

[0045] S2: according to the ball-to-material ratio of 12:1, the mixed material obtained in step S1 was put into a ball mill, and then alcohol was added thereto for ball milling at a rate of 450r / min for 14h; dried at 85°C for 40min; then 1.5g paraffin was added, and the mixture was pressed at a pressure of 60Mpa for 6min to obtain a pressed green sheet;

[0046] S3: The compact obtained in step S2 is heated to 1550° C. at a rate of 10° C. / min in a sintering furnace, and sintered for 3 hours at this temperature. After cooling, a cemented carbide can be obtained.

[0047] The nano nickel powder is also modified, and the specific modification method is:

[0048] S11: 5 parts of hexagonal boron nitride nanosheets, 3 parts of fullerene powder and 4 parts of carbon nanotubes are mixed and added into 8 parts of 5% by mass sodium silicate solution and stirred thoroughly to obtain hexagonal boron nitride nanosheets;

[0049] S12: Then, 2 parts of silane coupling agent KH550, 4 parts of TiC, 5 parts of hexagonal boron nitride nano-tablets and 8 parts of 8% by mass dopamine hydrochloride solution are fully blended to obtain a modified solution;

[0050] S13: irradiate the nano-nickel powder in a proton irradiation box for 15 minutes at an irradiation power of 350W. After the irradiation is completed, add the irradiated nano-nickel powder to the modification liquid at a weight ratio of 2:5, stir and modify it, filter and dry it. The average particle size of the hexagonal boron nitride nanosheets is 100nm. The stirring speed of the stirring modification treatment is 500r / min, and the stirring is for 1h.

[0051] Example 3

[0052] This embodiment provides a method for preparing high-performance nano-cemented carbide, comprising the following steps:

[0053] S1; according to the mass ratio of W:V:Cr being 97:0.4:0.5, ammonium metatungstate, vanadium oxalate and chromium acetate are taken, and the solid-liquid ratio is 1g:13ml, and the ammonium metatungstate, vanadium oxalate and chromium acetate are dissolved in deionized water, and dried to obtain a precursor; the calcination temperature is controlled to be 700°C, the calcination time is 2h, the hydrogen flow rate is 4L / min, the carbonization temperature is 1450°C, and the carbonization time is 2h, and the precursor is calcined and then reduced and carbonized by hydrogen to obtain the WC powder;

[0054] Lanthanum, cerium, yttrium and rubidium were mixed in a mass ratio of 1:1.4:1:0.7, and stirred at a rate of 250 r / min until uniform to obtain rare earth metal powder;

[0055] Weigh 95 g of WC powder, 5 g of tungsten powder, 2 g of nano nickel powder, 0.5 g of bismuth trioxide, 1.2 g of chromium boride and 1 g of rare earth metal powder and mix them to obtain a mixture;

[0056] S2: according to the ball-to-material ratio of 10:1, the mixed material obtained in step S1 is put into a ball mill, and then alcohol is added thereto for ball milling at a rate of 420r / min for 12h; dried at 85°C for 40min; then 1.3g PEG 1000 or paraffin is added, and pressed at a pressure of 55Mpa for 5min to obtain a pressed green sheet;

[0057] S3: The compact obtained in step S2 is heated to 1500° C. at a rate of 8° C. / min in a sintering furnace, and sintered for 2 hours at this temperature. After cooling, a cemented carbide can be obtained.

[0058] The nano nickel powder is also modified, and the specific modification method is:

[0059] S11: 3.5 parts of hexagonal boron nitride nanosheets, 2.5 parts of fullerene powder and 3.5 parts of carbon nanotubes are mixed and added into 6.5 parts of 5% by mass sodium silicate solution and stirred thoroughly to obtain hexagonal boron nitride nanosheets;

[0060] S12: Then, 1.5 parts of silane coupling agent KH550, 3 parts of TiC, 4 parts of hexagonal boron nitride nano-tablets and 6.5 parts of 8% by mass dopamine hydrochloride solution are mixed to obtain a modified solution;

[0061] S13: The nano-nickel powder is first irradiated in a proton irradiation box for 12.5 minutes at an irradiation power of 350W. After the irradiation is completed, the irradiated nano-nickel powder is added to the modification liquid at a weight ratio of 2:5, stirred for modification treatment, filtered, and dried. The average particle size of the hexagonal boron nitride nanosheets is 100nm, the stirring speed of the stirring modification treatment is 470r / min, and the stirring is for 1h.

[0062] Comparative Example 1

[0063] The difference from Example 3 is that in step S1, the WC powder is directly commercially available with a particle size of 30 - 40 nm, and the other steps remain unchanged.

[0064] Comparative Example 2

[0065] The difference from Example 3 is that in step S1, there is no rare earth metal powder, and the other steps remain unchanged.

[0066] Comparative Example 3

[0067] The difference from Example 3 is that in step S1, bismuth trioxide is not added, and the other steps remain unchanged.

[0068] Comparative Example 4

[0069] The difference from Example 3 is that in step S1, chromium boride is not added, and the other steps remain unchanged.

[0070] Comparative Example 5

[0071] The difference from Example 3 is that in step S1, ordinary nickel powder is used instead of the modified nano - nickel powder, and the other steps remain unchanged.

[0072] Performance Test:

[0073] The Rockwell hardness was detected according to GB5237 - 2004; its toughness was tested according to the test method for impact toughness of cemented carbide at room temperature in GB / T1817 - 2017; its flexural strength was tested according to the metal material bending test standard in GB / T232 - 2010. The results are shown in the following table.

[0074] Table 1

[0075] Test HV20 Hardness kg / mm Toughness MPa·m Flexural Strength MPa Example 1 2456 9.5 3457 Example 2 2487 9.8 3478 Example 3 2500 10.3 3513 Comparative Example 1 1623 8.1 2010 Comparative Example 2 2106 8.8 2218 Comparative Example 3 1986 8.4 2105 Comparative Example 4 2031 8.5 2189 Comparative Example 5 1658 8.2 2015

[0076] From the above performance test results, it can be seen that the cemented carbides prepared in Examples 1 - 3 have good hardness, toughness, flexural strength and other properties. Especially for Example 3, the comprehensive performance is better. While in Comparative Examples 1 - 5, because the necessary technical solutions are not adopted, their performance in the corresponding performance tests is significantly worse than that of the examples. The above experimental results further prove the importance of the technical solutions defined in the present invention for its technical effects. And it can be seen from Comparative Example 1, Comparative Example 5 and Example 3 that when using commercially available WC powder and ordinary nickel powder, the performance of the product shows an obvious downward trend, while using the specific WC powder and modified nickel powder of the present invention, the performance effect of the product is remarkable.

[0077] Based on the above test, the present invention places the product under 5% hydrochloric acid mist conditions for 24 hours, and heat treats it at 110°C for 12 hours, and finally scratches it 10 times at a load force of 10N. The above is one cycle, and the cycle is 10 times to test the corrosion resistance, high temperature resistance and scratch stability of the product. The test results are as follows:

[0078] Table 2

[0079] Test HV20 Hardness kg / mm Toughness MPa·m Flexural Strength MPa Example 1 2423 9.1 3423 Example 2 2445 9.2 3442 Example 3 2478 9.7 3478 Comparative Example 1 1021 7.0 1234 Comparative Example 2 1856 7.9 1476 Comparative Example 3 1652 7.3 1302 Comparative Example 4 1753 7.5 1324 Comparative Example 5 985 6.5 1076

[0080] From the stability test, it can be seen that in Comparative Example 5, ordinary nickel powder is used instead of the modified nano nickel powder, and the stability of the product deteriorates most significantly. Next, in Comparative Example 1, the WC powder is directly used from the market, and the product performance stability changes more significantly. The product raw materials of Example 3 of the present invention are used, and the performance stability of the product is the most significant.

[0081] Based on the corrosion resistance, high temperature resistance and scratch stability tests, the present invention further explores the effect of modified nano nickel powder on the performance stability of the product:

[0082] The nano nickel powder is also modified, and the specific modification method is:

[0083] S11: 3.5 parts of hexagonal boron nitride nanosheets, 2.5 parts of fullerene powder and 3.5 parts of carbon nanotubes are mixed and added into 6.5 parts of 5% by mass sodium silicate solution and stirred thoroughly to obtain hexagonal boron nitride nanosheets;

[0084] S12: Then, 1.5 parts of silane coupling agent KH550, 3 parts of TiC, 4 parts of hexagonal boron nitride nano-tablets and 6.5 parts of 8% by mass dopamine hydrochloride solution are mixed to obtain a modified solution;

[0085] S13: The nano-nickel powder is first irradiated in a proton irradiation box for 12.5 minutes at an irradiation power of 350W. After the irradiation is completed, the irradiated nano-nickel powder is added to the modification liquid at a weight ratio of 2:5, stirred for modification treatment, filtered, and dried. The average particle size of the hexagonal boron nitride nanosheets is 100nm, the stirring speed of the stirring modification treatment is 470r / min, and the stirring is for 1h.

[0086] Comparative Example 6 is different from Example 3 in that no silane coupling agent KH550 or TiC is added to the modified liquid.

[0087] Comparative Example 7 is different from Example 3 in that no hexagonal boron nitride nano-tablets are added to the modified solution.

[0088] Comparative Example 8 is different from Example 3 in that no fullerene powder and carbon nanotubes are added in the preparation of the hexagonal boron nitride nano-tablets.

[0089] Comparative Example 9, which is different from Example 3 in that hexagonal boron nitride nanosheets were not added during the preparation of the hexagonal boron nitride nanosheets.

[0090] Test the performance of the modified nickel powder under corrosion resistance, high temperature resistance and scratching conditions, and the test results are as follows

[0091] Table 3

[0092] Test HV20 Hardness kg / mm Toughness MPa·m Flexural Strength MPa Comparative Example 6 1687 8.5 2541 Comparative Example 7 1078 7.2 1378 Comparative Example 8 1389 8.3 2032 Comparative Example 9 1154 7.8 1889

[0093] It can be seen from Comparative Examples 6-9 that when hexagonal boron nitride nanosheets were not added to the modification solution, the performance of the product deteriorated significantly. Secondly, when hexagonal boron nitride nanosheets were not added during the preparation of the hexagonal boron nitride nanosheets, fullerene powder and carbon nanotubes were not added during the preparation of the hexagonal boron nitride nanosheets, and silane coupling agent KH550 and TiC were not added to the modification solution, the performance of the product showed a deteriorating trend to varying degrees. Only when the modification solution obtained by the specific method of the present invention was used, the performance effect of the product was the most significant, and the effects of using other methods instead were not as obvious as that of the present invention.

[0094] The above are the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A high performance nano cemented carbide, characterized in that: The invention comprises the following components in parts by weight: 90.5-98.5 parts of WC powder, 3-6 parts of tungsten powder, 1-3 parts of nano nickel powder, 0.3-0.7 parts of bismuth trioxide, 0.5-1.5 parts of chromium boride and 0.6-1.2 parts of rare earth metal powder.

2. A high performance nano-hard alloy according to claim 1, characterized in that: The rare earth metal powder includes lanthanum, cerium, yttrium and rubidium, and the mass ratio is 1:1.2-1.5:0.8-1.2:0.4-0.

8.

3. A high performance nano-hard alloy according to claim 1, characterized in that: The particle size of the WC powder is 0.3-0.8 nm; the particle size of the tungsten powder is 40-60 nm; the particle size of the nickel powder is 2-6 nm; the particle size of the bismuth trioxide is 3-7 nm; the particle size of the chromium boride is 1-4 nm; and the particle size of the rare earth metal is 50-70 nm.

4. A method for preparing high-performance nano-hard alloy, characterized in that: The steps include: S1; weigh 90.5-98.5 parts of WC powder, 3-6 parts of tungsten powder, 1-3 parts of nano nickel powder, 0.3-0.7 parts of bismuth trioxide, 0.5-1.5 parts of chromium boride and 0.6-1.2 parts of rare earth metal powder and mix them to obtain a mixture; S2: putting the mixed material obtained in step S1 into a ball mill, adding a ball milling medium thereto for ball milling; drying and pressing to obtain a compact; S3: Sintering the compact obtained in step S2 in a sintering furnace to obtain a cemented carbide.

5. The method for preparing a high-performance nano-hard alloy according to claim 4, characterized in that: The preparation process of WC powder in step S1 is: According to the mass ratio of WC:V:Cr in WC powder of 95-99:0.2-0.5:0.3-0.6, ammonium metatungstate, vanadium oxalate and chromium acetate are taken, and the ammonium metatungstate, vanadium oxalate and chromium acetate are dissolved in deionized water according to the solid-liquid ratio of 1g:10-15ml, and the precursor is obtained after drying; The calcination temperature is controlled to be 650-750° C., the calcination time is 1.5-2.5 h, the hydrogen flow rate is 3-5 L / min, the carbonization temperature is 1350-1500° C., and the carbonization time is 1-3 h. The precursor is calcined and then reduced and carbonized by hydrogen to obtain the WC powder.

6. The method for preparing a high-performance nano-hard alloy according to claim 4, characterized in that: In step S2, the ball-to-material ratio is 7-12:1; the ball milling medium is alcohol; the ball milling is performed at a rate of 350-450 r / min for 10-14 hours; and step S2 further includes 1-4 parts of sodium hexametaphosphate; The pressing pressure in step S2 is 40-60 MPa, and the pressing time is 3-6 minutes; the molding agent is PEG 1000 or paraffin; the sintering temperature in step S3 is 1450-1550° C., and the sintering time is 1-3 hours.

7. The method for preparing a high-performance nano-hard alloy according to claim 4, characterized in that: The nano nickel powder is also modified, and the specific modification method is: S11: adding 2-5 parts of hexagonal boron nitride nanosheets, 2-3 parts of fullerene powder and 3-4 parts of carbon nanotubes to 5-8 parts of 5% by mass sodium silicate solution and stirring thoroughly to obtain hexagonal boron nitride nanosheets; S12: Then, 1-2 parts of silane coupling agent KH550, 2-4 parts of TiC, 3-5 parts of hexagonal boron nitride nano-tablets and 5-8 parts of 8% by mass dopamine hydrochloride solution are mixed to obtain a modified solution; S13: irradiate the nano nickel powder in a proton irradiation box for 10-15 minutes at an irradiation power of 350W. After the irradiation is completed, add the irradiated nano nickel powder into the modified liquid at a weight ratio of 2:5, stir and modify, filter and dry.

8. The method for preparing a high-performance nano-hard alloy according to claim 7, characterized in that: The average particle size of the hexagonal boron nitride nanosheets is 100 nm.

9. The method for preparing a high-performance nano-hard alloy according to claim 7, characterized in that: The stirring speed of the modified treatment is 450-500 r / min, and the stirring is for 1 hour.

10. Use of the cemented carbide prepared according to any one of claims 1 to 9 in a milling cutter.