High-performance cemented carbide with dispersed and uniform tantalum carbide and preparation method thereof

Abstract

The application belongs to the technical field of hard alloy, and particularly relates to high-performance hard alloy with dispersed and uniform tantalum carbide and a preparation method thereof. The preparation method comprises the following steps: adding potassium fluotantalate solution into a cobalt-nickel solution; adjusting the pH of the solution to make cobalt, nickel and tantalum completely precipitate, and then filtering, washing with water and drying to obtain cobalt-nickel-tantalum precursors; then reducing, crushing and sieving to obtain precursor powder; mixing the precursor powder with carbon black, tungsten carbide and paraffin, and then wet ball-milling, spray granulating, preparing a compact and sintering to obtain high-performance hard alloy. By adding nickel element, using a liquid-liquid mixing method and reducing, superfine cobalt-nickel solid solution powder is obtained, which can improve the toughness of the alloy; the conversion of tantalum is completed in the sintering process, which is beneficial to the dispersion of tantalum and the strengthening of the alloy performance, improves the solid solution amount of tantalum in cobalt-nickel, inhibits the sintering growth of WC, and improves the hardness and wear resistance of the alloy.

Description

Technical Field

[0001] This application belongs to the field of cemented carbide technology, specifically a high-performance cemented carbide with uniformly dispersed tantalum carbide and its preparation method. Background Technology

[0002] Cemented carbide is a key structural material that combines high wear resistance and toughness. Thanks to its excellent mechanical properties, it is widely used in cutting tools, mining tools, wear-resistant parts, and special working conditions. However, the working conditions in different applications vary greatly, leading to significant differences in the performance requirements of cemented carbide. For example, cutting tools need to balance high hardness to resist wear and high toughness to resist impact, while mining tools place greater emphasis on fracture resistance under extreme conditions.

[0003] In traditional cemented carbide systems, hardness and toughness always present an inherent contradiction of "one for the other": if hardness is increased to enhance wear resistance by adjusting the binder phase content or refining the hard phase grains, it often leads to a significant decrease in the material's toughness; conversely, if the proportion of the binder phase is increased to improve toughness, hardness and wear resistance are sacrificed. This contradiction makes it difficult for traditional processes to produce high-performance products that combine "ultra-high hardness" and "excellent toughness," which has long restricted the application of cemented carbide in high-end fields.

[0004] With the continuous exploration of researchers, a series of innovative technologies that break through traditional bottlenecks have emerged. For example, by introducing trace amounts of functional additives, adopting novel hard phases and binder phases such as bicrystalline tungsten carbide (WC), or optimizing sintering processes to achieve atomic-level uniform dispersion, the "hardness-toughness" opposition has been successfully broken, enabling the hardness and toughness of cemented carbides to be improved simultaneously compared to traditional products. However, these innovative methods are also accompanied by new technical challenges. Taking the additive modification strategy as an example, although trace additives can effectively improve toughness while maintaining the same hardness through mechanisms such as refining grains and optimizing interface bonding, when the amount of additives exceeds the critical value, agglomeration and segregation can easily occur inside the alloy due to uneven element diffusion. This agglomeration not only destroys the uniformity of the material composition but also forms brittle second phases (such as carbide and oxide inclusions), becoming weak points of stress concentration, resulting in a significant decrease in the material's fatigue resistance and fracture resistance, ultimately greatly shortening the service life of the product.

[0005] To address the difficulty of additive dispersion, the patent "A cemented carbide for mining tools with dispersed tantalum carbide and its preparation method" proposes to add polytantaloxane to a WC-Co mixture, using glucose as a carbon source to generate ultrafine tantalum carbide particles through in-situ reaction, and combining this with a staged sintering process to control its precipitation and dispersion distribution. This avoids the agglomeration and irregular morphology caused by traditional additive methods, achieving a uniform dispersion structure. However, glucose decomposes during sintering, introducing oxygen and making it difficult to control the carbon content of the alloy, which can easily lead to decarburization and performance degradation. Summary of the Invention

[0006] To address the aforementioned issues, this application proposes a high-performance cemented carbide with uniformly dispersed tantalum carbide and its preparation method.

[0007] According to a first aspect of this application, this application provides a method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide, comprising the following steps:

[0008] S1. Obtain a cobalt-nickel solution and a potassium fluorotantalate solution. Add the potassium fluorotantalate solution to the cobalt-nickel solution and stir to obtain a cobalt-nickel-tantalum solution.

[0009] S2. Adjust the pH of the cobalt-nickel-tantalum solution to completely precipitate cobalt, nickel, and tantalum, then filter, wash with water, and dry to obtain the cobalt-nickel-tantalum precursor;

[0010] S3. The cobalt-nickel-tantalum precursor is reduced, crushed, and sieved to obtain precursor powder;

[0011] S4. The precursor powder is mixed with carbon black, tungsten carbide and paraffin wax and wet ball milled, and then spray granulated to obtain a mixture.

[0012] S5. Prepare a compact using the mixture, and sinter the compact to obtain a high-performance cemented carbide.

[0013] Furthermore, in step S1, the mass ratio of cobalt to nickel in the cobalt-nickel solution is (4~9):1, and the mass ratio of the total mass of cobalt and nickel to the mass of tantalum in the cobalt-nickel-tantalum solution is (12~20):1.

[0014] Furthermore, in step S4, the mass of tantalum in the precursor powder is 0.3% to 0.5% of the total mass of the precursor powder and the tungsten carbide, and the total mass of cobalt and nickel in the precursor powder is 0.6% of the total mass of the precursor powder and the tungsten carbide.

[0015] Furthermore, in step S4, the amount of carbon black added is 1.0 to 1.1 times the theoretical amount.

[0016] Furthermore, in step S4, the mass of the paraffin is 2.0% to 2.5% of the total mass of the precursor powder and the tungsten carbide.

[0017] Further, step S1 includes dissolving cobalt acetate and nickel nitrate hexahydrate in water and stirring to obtain the cobalt-nickel solution; dissolving potassium fluorotantalate in water and stirring to obtain the potassium fluorotantalate solution.

[0018] Furthermore, in step S2, ammonia is added to the cobalt-nickel-tantalum solution to adjust the pH to 8-9 so that cobalt, nickel, and tantalum are completely precipitated.

[0019] Furthermore, in step S3, the reduction process is as follows:

[0020] A. In an N2 atmosphere, heat to 250~300℃ at a rate of 10℃ / min and hold for 30~60min;

[0021] B. In an H2 atmosphere, heat to 450~500℃ at a rate of 10℃ / min and hold for 90~120min;

[0022] C. In an H2 atmosphere, heat to 600~650℃ at a rate of 10℃ / min and hold for 90~120min;

[0023] D. Cool the atmosphere to 290~310℃ in H2 atmosphere, convert it to N2 atmosphere and cool it to room temperature.

[0024] Furthermore, in step S4, the ball milling medium for the wet ball mill is anhydrous ethanol, the ball-to-material ratio is (5~8):1, and the time is 30~48h.

[0025] Furthermore, in step S4, the temperature of the spray granulation is 90~95℃.

[0026] Furthermore, in step S5, the sintering process is as follows:

[0027] I. In an H2 atmosphere, heat to 250~280℃ at a rate of 10℃ / min and hold for 30~60min;

[0028] II. Under vacuum conditions, heat to 1150~1200℃ at a rate of 10℃ / min and hold for 60~90min;

[0029] III. Under vacuum conditions, heat to 1300~1350℃ at a rate of 5℃ / min and hold for 120~180min;

[0030] IV. Under vacuum conditions, heat to 1380~1400℃ at a rate of 5℃ / min and hold for 60~120min;

[0031] V. In an argon atmosphere at a pressure of 8-10 MPa, heat to 1420-1500℃ and hold for 180-240 minutes.

[0032] Furthermore, step S1 includes dissolving cobalt acetate and nickel nitrate hexahydrate in water and stirring to obtain the cobalt-nickel solution.

[0033] Furthermore, step S1 includes dissolving potassium fluorotantalate in water and stirring to obtain the potassium fluorotantalate solution.

[0034] According to a second aspect of this application, this application provides a high-performance cemented carbide with uniformly dispersed tantalum carbide, prepared by the above-described method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide. The high-performance cemented carbide has a hardness greater than or equal to 1500 and a fracture toughness greater than or equal to 12 MPa·m. 1 / 2 The strength is greater than or equal to 3150 MPa.

[0035] This application proposes a method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide, which yields the following beneficial effects:

[0036] 1. By adding nickel and preparing cobalt-nickel-tantalum ternary precursor powder, cobalt in the FCC phase and the melt of cobalt and nickel are obtained. This not only shortens the migration distance of tantalum in cobalt-nickel, but also improves the dispersibility of tantalum and increases the solid solubility of tantalum in the alloy.

[0037] 2. By controlling the cobalt-nickel ratio, ultrafine cobalt-nickel solid solution powder is obtained through liquid-liquid mixing and hydrogen reduction, which helps to improve the toughness of the alloy.

[0038] 3. The conversion of tantalum is completed in the cemented carbide sintering process, which is beneficial to the dispersion of tantalum and the enhancement of alloy performance. The solid solution content of tantalum in cobalt-nickel is increased during the sintering process, the sintering growth of WC is inhibited, and the hardness and wear resistance of the alloy are improved. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0040] Figure 1 Metallographic images of the high-performance cemented carbide prepared in Example 1 of this application;

[0041] Figure 2Metallographic images of the cemented carbide prepared in Comparative Example 1 of this application;

[0042] Figure 3 Metallographic images of the cemented carbide prepared in Comparative Example 2 of this application;

[0043] Figure 4 Metallographic images of the cemented carbide prepared in Comparative Example 3 of this application;

[0044] Figure 5 Metallographic image of the cemented carbide prepared in Comparative Example 4 of this application.

[0045] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] According to a first aspect of this application, this application provides a method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide, comprising the following steps:

[0048] S1. Obtain a cobalt-nickel solution and a potassium fluorotantalate solution. Add the potassium fluorotantalate solution to the cobalt-nickel solution and stir to obtain a cobalt-nickel-tantalum solution.

[0049] Preferably, cobalt acetate and nickel nitrate hexahydrate are dissolved in water and stirred to obtain a cobalt-nickel solution, wherein the mass ratio of cobalt to nickel is (4~9):1; potassium fluorotantalate is dissolved in water and stirred to obtain a potassium fluorotantalate solution, which is then added to the cobalt-nickel solution and stirred to obtain a cobalt-nickel-tantalum solution, wherein the mass ratio of the total mass of cobalt and nickel to the mass of tantalum is (12~20):1. Specifically, the mass ratio of cobalt to nickel in the cobalt-nickel solution can be any one of 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or any range between two of these, and the mass ratio of the total mass of cobalt and nickel to the mass of tantalum in the cobalt-nickel-tantalum solution can be any one of 12:1, 14:1, 16:1, 18:1, 20:1 or any range between two of these.

[0050] S2. Adjust the pH of the cobalt-nickel-tantalum solution to completely precipitate cobalt, nickel, and tantalum. Filter, wash with water, and dry to obtain the cobalt-nickel-tantalum precursor.

[0051] Preferably, ammonia is added to the cobalt-nickel-tantalum solution to adjust the pH to 8-9, causing cobalt, nickel, and tantalum to precipitate completely. The solution is then filtered, washed with water, and dried to obtain the cobalt-nickel-tantalum precursor. Specifically, the pH can be adjusted to any one or any two of 8, 8.2, 8.4, 8.6, 8.8, and 9.

[0052] S3. Reduce, crush, and sieve the cobalt-nickel-tantalum precursor to obtain precursor powder;

[0053] The preferred reduction process is as follows:

[0054] A. In an N2 atmosphere, heat to 250~300℃ at a rate of 10℃ / min and hold for 30~60min;

[0055] B. In an H2 atmosphere, heat to 450~500℃ at a rate of 10℃ / min and hold for 90~120min;

[0056] C. In an H2 atmosphere, heat to 600~650℃ at a rate of 10℃ / min and hold for 90~120min;

[0057] D. Cool the atmosphere to 290~310℃ in H2 atmosphere, convert it to N2 atmosphere and cool it to room temperature.

[0058] In steps S1 to S3 above, cobalt, nickel, and tantalum are first prepared into a solution and then uniformly mixed together through liquid-liquid doping. After precipitation and reduction, ultrafine precursor powder is obtained. Compared to directly mixing solid powders containing cobalt, nickel, and tantalum, the precursor powder exhibits a more uniform distribution of cobalt, nickel, and tantalum, which helps improve the alloy's toughness. Furthermore, since cobalt, nickel, and tantalum have different reduction temperatures, staged reduction can be employed to ensure complete reduction and uniform dispersion of the three components at each holding stage.

[0059] S4. The precursor powder is mixed with carbon black, tungsten carbide and paraffin wax and wet ball milled, and then spray granulated to obtain the mixture.

[0060] Preferably, anhydrous ethanol is used as the ball milling medium. The precursor powder is mixed with tungsten carbide and paraffin wax and wet ball milled at a ball-to-material ratio of (5~8):1 for 30~48 hours. Then, spray granulation is performed at 90~95℃ to obtain a mixture. The mass of tantalum in the precursor powder is 0.3%~0.5% of the total mass of the precursor powder and tungsten carbide, and the total mass of cobalt and nickel in the precursor powder is 0.6% of the total mass of the precursor powder and tungsten carbide. The mass of paraffin wax is 2.0%~2.5% of the total mass of the precursor powder and tungsten carbide. The amount of carbon black added is 1.0~1.1 times the theoretical amount. Specifically, the ball-to-material ratio in wet ball milling can be any one of 5:1, 6:1, 7:1, 8:1, or any combination thereof; the time can be any one of 30h, 32h, 34h, 36h, 38h, 40h, or any combination thereof; the spray granulation temperature can be any one of 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, or any combination thereof; the mass of tantalum in the precursor powder can be any one of 0.3%, 0.35%, 0.4%, 0.45%, 0.5% of the total mass of the precursor powder and tungsten carbide, or any combination thereof; and the mass of paraffin can be any one of 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5% of the total mass of the precursor powder and tungsten carbide, or any combination thereof.

[0061] S5. Prepare a compact using a mixture, and sinter the compact to obtain a high-performance cemented carbide.

[0062] The preferred sintering process is as follows:

[0063] I. In an H2 atmosphere, heat to 250~280℃ at a rate of 10℃ / min and hold for 30~60min;

[0064] II. Under vacuum conditions, heat to 1150~1200℃ at a rate of 10℃ / min and hold for 60~90min;

[0065] III. Under vacuum conditions, heat to 1300~1350℃ at a rate of 5℃ / min and hold for 120~180min;

[0066] IV. Under vacuum conditions, heat to 1380~1400℃ at a rate of 5℃ / min and hold for 60~120min;

[0067] V. In an argon atmosphere at a pressure of 8-10 MPa, heat to 1420-1500℃ and hold for 180-240 minutes.

[0068] In steps S4 and S5 above, adding carbon black can both fully reduce unreduced tantalum oxide and react with tantalum to form tantalum carbide. Therefore, the oxygen content of the precursor powder can be measured before wet ball milling, and the theoretical amount of carbon to be added can be calculated based on the oxygen content. Then, the precursor powder is mixed with carbon black, tungsten carbide, and paraffin wax for wet ball milling, followed by spray granulation to obtain a mixture. During the sintering stage, carbon black is used to consume the oxygen and complete the conversion of tantalum, which is beneficial for further dispersion of tantalum and further increases the solid solution content of tantalum in cobalt-nickel, thereby strengthening the alloy properties. In some preferred embodiments of this application, a segmented sintering process can be adopted. First, paraffin wax is removed at a low temperature, followed by solid-state sintering at a higher temperature. Segmented sintering during solid-state sintering allows the unreduced tantalum oxide in the precursor powder to fully react and obtain a cobalt-nickel-tantalum mixed powder, thereby strengthening the toughness of the cemented carbide. Finally, liquid-state sintering is performed at a higher temperature to obtain a high-performance cemented carbide.

[0069] According to a second aspect of this application, this application provides a high-performance cemented carbide with uniformly dispersed tantalum carbide, prepared by the above-described method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide. The high-performance cemented carbide has a hardness (HV10) greater than or equal to 1500 and a fracture toughness greater than or equal to 12 MPa·m. 1 / 2 The strength is greater than or equal to 3150 MPa.

[0070] The technical solution of this application will be further described below with reference to specific embodiments.

[0071] Example 1

[0072] A method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide includes the following steps:

[0073] S1. Cobalt acetate and nickel nitrate hexahydrate are dissolved in water and stirred to obtain a cobalt-nickel solution, wherein the mass ratio of cobalt to nickel is 9:1; potassium fluorotantalate is dissolved in water and stirred to obtain a potassium fluorotantalate solution; the potassium fluorotantalate solution is added to the cobalt-nickel solution and stirred to obtain a cobalt-nickel-tantalum solution, wherein the total mass ratio of cobalt and nickel to tantalum is 15:1.

[0074] S2. Add ammonia to the cobalt-nickel-tantalum solution to adjust the pH to 8.5 so that cobalt, nickel and tantalum are completely precipitated. Filter, wash with water and dry to obtain the cobalt-nickel-tantalum precursor.

[0075] S3. Reduce, crush, and sieve the cobalt-nickel-tantalum precursor to obtain precursor powder;

[0076] The reduction process is as follows:

[0077] A. In an N2 atmosphere, heat to 300℃ at a rate of 10℃ / min and hold for 30min;

[0078] B. In an H2 atmosphere, heat to 500℃ at a rate of 10℃ / min and hold for 90min;

[0079] C. In an H2 atmosphere, heat to 600℃ at a rate of 10℃ / min and hold for 120min;

[0080] D. Cool the atmosphere to 300°C in H2 atmosphere, then switch to N2 atmosphere and cool to room temperature.

[0081] S4. Using anhydrous ethanol as the ball milling medium, the precursor powder is mixed with tungsten carbide and paraffin wax and wet ball milled at a ball-to-material ratio of 5:1 for 35 hours. Then, spray granulation is performed at 93°C to obtain a mixture. The mass of tantalum in the precursor powder is 0.4% of the total mass of the precursor powder and tungsten carbide, and the mass of paraffin wax is 2.2% of the total mass of the precursor powder and tungsten carbide.

[0082] S5. Prepare a compact using a mixture, and sinter the compact to obtain a high-performance cemented carbide;

[0083] The sintering process is as follows:

[0084] I. In an H2 atmosphere, heat to 280℃ at a rate of 10℃ / min and hold for 30min;

[0085] II. Under vacuum conditions, heat to 1150℃ at a rate of 10℃ / min and hold for 60min;

[0086] III. Under vacuum conditions, heat to 1350℃ at a rate of 5℃ / min and hold for 180min;

[0087] IV. Under vacuum conditions, heat to 1400℃ at a rate of 5℃ / min and hold for 60min;

[0088] V. In an argon atmosphere at a pressure of 9 MPa, heat to 1430℃ and hold for 180 min.

[0089] The properties of the high-performance cemented carbide prepared in this embodiment are shown in Table 1, and its metallographic images are shown below. Figure 1 As shown.

[0090] Example 2

[0091] A method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide includes the following steps:

[0092] S1. Cobalt acetate and nickel nitrate hexahydrate are dissolved in water and stirred to obtain a cobalt-nickel solution, wherein the mass ratio of cobalt to nickel is 4:1; potassium fluorotantalate is dissolved in water and stirred to obtain a potassium fluorotantalate solution; the potassium fluorotantalate solution is added to the cobalt-nickel solution and stirred to obtain a cobalt-nickel-tantalum solution, wherein the total mass ratio of cobalt and nickel to tantalum is 20:1.

[0093] S2. Add ammonia to the cobalt-nickel-tantalum solution to adjust the pH to 8.5 so that cobalt, nickel and tantalum are completely precipitated. Filter, wash with water and dry to obtain the cobalt-nickel-tantalum precursor.

[0094] S3. Reduce, crush, and sieve the cobalt-nickel-tantalum precursor to obtain precursor powder;

[0095] The reduction process is as follows:

[0096] A. In an N2 atmosphere, heat to 300℃ at a rate of 10℃ / min and hold for 30min;

[0097] B. In an H2 atmosphere, heat to 500℃ at a rate of 10℃ / min and hold for 90min;

[0098] C. In an H2 atmosphere, heat to 600℃ at a rate of 10℃ / min and hold for 120min;

[0099] D. Cool the atmosphere to 300°C in H2 atmosphere, then switch to N2 atmosphere and cool to room temperature.

[0100] S4. Using anhydrous ethanol as the ball milling medium, the precursor powder was mixed with tungsten carbide and paraffin wax and wet ball milled at a ball-to-material ratio of 8:1 for 33 hours. Then, spray granulation was performed at 93°C to obtain a mixture. The mass of tantalum in the precursor powder was 0.3% of the total mass of the precursor powder and tungsten carbide, and the mass of paraffin wax was 2.0% of the total mass of the precursor powder and tungsten carbide.

[0101] S5. Prepare a compact using a mixture, and sinter the compact to obtain a high-performance cemented carbide;

[0102] The sintering process is as follows:

[0103] I. In an H2 atmosphere, heat to 280℃ at a rate of 10℃ / min and hold for 30min;

[0104] II. Under vacuum conditions, heat to 1200℃ at a rate of 10℃ / min and hold for 60min;

[0105] III. Under vacuum conditions, heat to 1350℃ at a rate of 5℃ / min and hold for 120min;

[0106] IV. Under vacuum conditions, heat to 1400℃ at a rate of 5℃ / min and hold for 60min;

[0107] V. In an argon atmosphere at a pressure of 9 MPa, heat to 1430℃ and hold for 180 min.

[0108] The properties of the high-performance cemented carbide prepared in this embodiment are shown in Table 1, and no abnormalities were observed in the metallographic structure.

[0109] Example 3

[0110] A method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide includes the following steps:

[0111] S1. Cobalt acetate and nickel nitrate hexahydrate are dissolved in water and stirred to obtain a cobalt-nickel solution, wherein the mass ratio of cobalt to nickel is 9:1; potassium fluorotantalate is dissolved in water and stirred to obtain a potassium fluorotantalate solution; the potassium fluorotantalate solution is added to the cobalt-nickel solution and stirred to obtain a cobalt-nickel-tantalum solution, wherein the total mass ratio of cobalt and nickel to tantalum is 12:1.

[0112] S2. Add ammonia to the cobalt-nickel-tantalum solution to adjust the pH to 8.5 so that cobalt, nickel and tantalum are completely precipitated. Filter, wash with water and dry to obtain the cobalt-nickel-tantalum precursor.

[0113] S3. Reduce, crush, and sieve the cobalt-nickel-tantalum precursor to obtain precursor powder;

[0114] The reduction process is as follows:

[0115] A. In an N2 atmosphere, heat to 300℃ at a rate of 10℃ / min and hold for 60min;

[0116] B. In an H2 atmosphere, heat to 500℃ at a rate of 10℃ / min and hold for 90min;

[0117] C. In an H2 atmosphere, heat to 600℃ at a rate of 10℃ / min and hold for 120min;

[0118] D. Cool the atmosphere to 300°C in H2 atmosphere, then switch to N2 atmosphere and cool to room temperature.

[0119] S4. Using anhydrous ethanol as the ball milling medium, the precursor powder is mixed with tungsten carbide and paraffin wax and wet ball milled at a ball-to-material ratio of 5:1 for 48 hours. Then, spray granulation is performed at 93°C to obtain a mixture. The mass of tantalum in the precursor powder is 0.5% of the total mass of the precursor powder and tungsten carbide, and the mass of paraffin wax is 2.3% of the total mass of the precursor powder and tungsten carbide.

[0120] S5. Prepare a compact using a mixture, and sinter the compact to obtain a high-performance cemented carbide;

[0121] The sintering process is as follows:

[0122] I. In an H2 atmosphere, heat to 280℃ at a rate of 10℃ / min and hold for 30min;

[0123] II. Under vacuum conditions, heat to 1200℃ at a rate of 10℃ / min and hold for 60min;

[0124] III. Under vacuum conditions, heat to 1350℃ at a rate of 5℃ / min and hold for 150min;

[0125] IV. Under vacuum conditions, heat to 1400℃ at a rate of 5℃ / min and hold for 60min;

[0126] V. In an argon atmosphere at a pressure of 9 MPa, heat to 1430℃ and hold for 180 min.

[0127] The properties of the high-performance cemented carbide prepared in this embodiment are shown in Table 1, and no abnormalities were observed in the metallographic structure.

[0128] Comparative Example 1

[0129] The only difference between this comparative example and Example 1 is that in step S1, cobalt acetate is used to prepare a cobalt solution, and potassium fluorotantalate solution is added to the cobalt solution to obtain a cobalt-tantalum solution; subsequently, the same method is used to prepare cobalt-tantalum precursor powder using the cobalt-tantalum solution, and hard alloy is obtained.

[0130] The properties of the cemented carbide prepared in this comparative example are shown in Table 1, and its metallographic images are shown below. Figure 2 As shown in the figure, tantalum carbide enrichment is observed in its metallographic structure.

[0131] Comparative Example 2

[0132] The only difference between this comparative example and Example 1 is that in step S1, only a cobalt-nickel solution is prepared without adding potassium fluorotantalate solution; subsequently, the same method is used to prepare cobalt-nickel precursor powder using the cobalt-nickel solution, and cemented carbide is obtained.

[0133] The properties of the cemented carbide prepared in this comparative example are shown in Table 1, and its metallographic images are shown below. Figure 3 As shown in the figure, its metallographic structure has many coarse particles.

[0134] Comparative Example 3

[0135] The only difference between this comparative example and Example 1 is that steps S1 to S3 are omitted, and in step S4, cobalt powder, nickel powder, and tantalum carbide powder in the same proportion are added to replace the precursor powder for wet ball milling; subsequently, the same method is used to prepare cemented carbide.

[0136] The properties of the cemented carbide prepared in this comparative example are shown in Table 1, and its metallographic images are shown below. Figure 4 As shown in the figure, the metallographic structure shows an enrichment of tantalum carbide and contains a large number of coarse particles.

[0137] Comparative Example 4

[0138] The only difference between this comparative example and Example 1 is that: in step S1, only a cobalt-nickel solution is prepared without adding potassium fluorotantalate solution; subsequently, the same method is used to prepare cobalt-nickel precursor powder using the cobalt-nickel solution; in step S4, tantalum carbide powder in the same proportion is added for wet ball milling; subsequently, the same method is used to prepare cemented carbide.

[0139] The properties of the cemented carbide prepared in this comparative example are shown in Table 1, and its metallographic images are shown below. Figure 5 As shown in the figure, tantalum carbide enrichment is observed in its metallographic structure.

[0140] Table 1

[0141]

[0142] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide, characterized in that, Includes the following steps: S1. Obtain a cobalt-nickel solution and a potassium fluorotantalate solution. Add the potassium fluorotantalate solution to the cobalt-nickel solution and stir to obtain a cobalt-nickel-tantalum solution. S2. Adjust the pH of the cobalt-nickel-tantalum solution to completely precipitate cobalt, nickel, and tantalum, then filter, wash with water, and dry to obtain the cobalt-nickel-tantalum precursor; S3. The cobalt-nickel-tantalum precursor is reduced, crushed, and sieved to obtain precursor powder; S4. The precursor powder is mixed with carbon black, tungsten carbide and paraffin wax and wet ball milled, and then spray granulated to obtain a mixture. S5. Prepare a compact using the mixture, and sinter the compact to obtain a high-performance cemented carbide; In step S1, the mass ratio of cobalt to nickel in the cobalt-nickel solution is (4~9):1, and the mass ratio of the total mass of cobalt and nickel to the mass of tantalum in the cobalt-nickel-tantalum solution is (12~20):

1. In step S3, the reduction process is as follows: A. In an N2 atmosphere, heat to 250~300℃ at a rate of 10℃ / min and hold for 30~60min; B. In an H2 atmosphere, heat to 450~500℃ at a rate of 10℃ / min and hold for 90~120min; C. In an H2 atmosphere, heat to 600~650℃ at a rate of 10℃ / min and hold for 90~120min; D. Cool the atmosphere to 290~310℃ in H2 atmosphere, convert it to N2 atmosphere and cool it to room temperature.

2. The method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide according to claim 1, characterized in that, In step S4, the mass of tantalum in the precursor powder is 0.3% to 0.5% of the total mass of the precursor powder and the tungsten carbide, and the total mass of cobalt and nickel in the precursor powder is 0.6% of the total mass of the precursor powder and the tungsten carbide.

3. The method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide according to claim 1, characterized in that, Step S1 includes dissolving cobalt acetate and nickel nitrate hexahydrate in water and stirring to obtain the cobalt-nickel solution; dissolving potassium fluorotantalate in water and stirring to obtain the potassium fluorotantalate solution.

4. The method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide according to claim 1, characterized in that, In step S2, ammonia is added to the cobalt-nickel-tantalum solution to adjust the pH to 8-9 so that cobalt, nickel and tantalum are completely precipitated.

5. The method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide according to claim 1, characterized in that, In step S4, the ball milling medium for the wet ball mill is anhydrous ethanol, the ball-to-material ratio is (5~8):1, and the time is 30~48h.

6. The method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide according to claim 1, characterized in that, In step S4, the temperature of the spray granulation is 90~95℃.

7. The method for preparing a high-performance cemented carbide with uniformly dispersed tantalum carbide according to claim 1, characterized in that, In step S5, the sintering process is as follows: I. In an H2 atmosphere, heat to 250~280℃ at a rate of 10℃ / min and hold for 30~60min; II. Under vacuum conditions, heat to 1150~1200℃ at a rate of 10℃ / min and hold for 60~90min; III. Under vacuum conditions, heat to 1300~1350℃ at a rate of 5℃ / min and hold for 120~180min; IV. Under vacuum conditions, heat to 1380~1400℃ at a rate of 5℃ / min and hold for 60~120min; V. In an argon atmosphere at a pressure of 8-10 MPa, heat to 1420-1500℃ and hold for 180-240 minutes.

8. A high-performance cemented carbide with uniformly dispersed tantalum carbide, characterized in that, The high-performance cemented carbide is prepared by the method for preparing uniformly dispersed tantalum carbide according to any one of claims 1 to 7, wherein the hardness of the high-performance cemented carbide is greater than or equal to 1500 and the fracture toughness is greater than or equal to 12 MPa·m. 1 / 2 The strength is greater than or equal to 3150 MPa.

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