Material for metal ceramic cutter and preparation method thereof

Abstract

The invention belongs to the technical field of metal ceramic composite materials, and particularly relates to a material for a metal ceramic cutter and a preparation method of the material. The material for the metal ceramic cutter is prepared from the following raw materials in percentage by weight: 10 to 14 weight percent of metal binding phase, 6 to 13 weight percent of tungsten oxide whisker, 3 to 8 weight percent of tantalum and hafnium carbide powder and the balance of modified titanium carbonitride powder, the modified titanium carbonitride powder is prepared through the following preparation processes that copper salt and scandium salt are added into water to be dissolved, then titanium carbonitride is added for ultrasonic dispersion, the pH is adjusted to 8.5-9.5, then a heating reaction is conducted, filtering, washing and drying are conducted, and solid powder is obtained; and calcining the solid powder in a mixed gas atmosphere of nitrogen and hydrogen to obtain the modified titanium carbonitride. The material for the metal ceramic cutter has excellent high temperature resistance and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of metal-ceramic composite materials technology, specifically relating to a metal-ceramic cutting tool material and its preparation method. Background Technology

[0002] Machining is one of the main forming methods for parts. During machining, the mechanical properties of the tool material have a crucial impact on cutting performance. Therefore, the selection of tool material directly affects machining efficiency, machining quality, and machining cost. With the continuous advancement of manufacturing, the pursuit of product precision and production efficiency is becoming increasingly urgent. Machining technology is also developing towards high precision, high efficiency, low energy consumption, and low pollution. To improve machining efficiency, high-speed cutting methods are usually adopted. During this process, the intense friction between the tool and the workpiece generates high temperatures and pressures. Therefore, the tool is required to have good hardness, wear resistance, thermal conductivity, high strength, and corrosion resistance. However, traditional tool materials are gradually becoming insufficient to meet the actual needs of modern production.

[0003] Commonly used materials for cutting tools include cemented carbide, alumina-based ceramics, cubic boron nitride, and cermets. Among these, cermet materials, composed of nitride, carbide, or oxide ceramic phases and single or composite metal binder phases, possess unique advantages as tool materials, combining the high strength, hardness, and wear resistance of ceramics with the good toughness and ductility of metals. With the expanding applications of cutting tools, they often need to operate in extreme environments, such as high-temperature environments and chemically corrosive media. To prevent tool deformation or failure and extend tool life, modifying cermet materials by adding reinforcing phases to improve their high-temperature stability while maintaining high strength, hardness, and toughness, thus meeting the demands of extreme operating environments, is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] The primary objective of this invention is to provide a material for metal-ceramic cutting tools, which possesses excellent high-temperature resistance and superior mechanical properties.

[0005] The second objective of this invention is to provide a method for preparing the above-mentioned metal-ceramic cutting tool material.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A metal-ceramic cutting tool material is composed of the following raw materials by weight percentage: 10-14 wt% metal binder phase, 6-13 wt% tungsten oxide whiskers, 3-8 wt% tantalum carbide hafnium powder, and the balance being modified titanium carbonitride powder. The modified titanium carbonitride powder is prepared by the following process: (1) Dissolve copper salt and scandium salt in water, then add titanium carbonitride and disperse ultrasonically. Adjust the pH to 8.5-9.5 and then heat the reaction. Filter, wash and dry to obtain solid powder; (2) The solid powder is calcined in a mixed atmosphere of nitrogen and hydrogen to obtain the modified titanium carbonitride.

[0007] Further, the molar ratio of titanium carbonitride, copper salt and scandium salt in step (1) is 1:(0.08-0.15):(0.02-0.06).

[0008] Furthermore, the heating reaction in step (1) is carried out at a temperature of 120-150°C for 10-12 hours.

[0009] Further, in step (2), the volume ratio of nitrogen to hydrogen is 1:1-3; the calcination temperature is 1200-1400℃ and the time is 2-3h.

[0010] Furthermore, the tungsten oxide whiskers are prepared by the following process: Sodium tungstate was dissolved in water, and the pH was adjusted to 1.5-2.5. The mixture was stirred until a precipitate formed. The mixture was allowed to stand for 20-25 hours, and the pH was adjusted to 9-10. After stirring for another 2-5 hours, sodium sulfide was added to carry out a hydrothermal reaction. The mixture was then filtered, washed, and dried to obtain the tungsten oxide whiskers.

[0011] Furthermore, the mass ratio of sodium sulfide to sodium tungstate is 1:8-10; the hydrothermal reaction temperature is 140-170℃, and the time is 35-40h.

[0012] Furthermore, the metal binder phase consists of equimolar amounts of Fe, Co, and Ni.

[0013] The preparation method of the above-mentioned metal-ceramic cutting tool material includes the following steps: According to the stated weight percentages, the metal binder phase, tungsten oxide whiskers, tantalum carbide hafnium powder, and modified titanium carbonitride powder are ball-milled and mixed, and then pre-pressed to obtain a compact; the compact is then sintered under vacuum conditions to obtain the final product.

[0014] Furthermore, the pre-compression pressure is 200-300 MPa, and the time is 2-5 min; the vacuum degree of the vacuuming is 10-20 Pa.

[0015] Furthermore, the sintering temperature is 1250-1550℃ and the time is 60-80min.

[0016] The beneficial technical effects of this invention are as follows: 1. This invention uses copper-scandium composite-modified titanium carbonitride as a raw material to prepare cermet cutting tools, which can effectively improve the mechanical properties and sintering performance of the material. Copper has good ductility and softness, while scandium can form a solid solution with titanium carbonitride, inhibiting grain boundary diffusion and refining grains. The combination of the two modifies titanium carbonitride, maintaining its high hardness while delaying ceramic brittleness, improving the material's strength and toughness, and forming a lubricating film on the material surface, reducing the coefficient of friction and further improving the material's wear resistance. Furthermore, copper has a low melting point and good sintering properties, forming a liquid phase during sintering, promoting atomic rearrangement, and improving the sintering performance of the ceramic. Scandium, as a rare earth element, adsorbs impurities and purifies grain boundaries, and calcination in a nitrogen atmosphere forms a dense nitride layer, improving the material's corrosion resistance.

[0017] 2. This invention adds tungsten oxide whiskers and tantalum carbide hafnium powder as reinforcing phases to cermets, thereby improving the high-temperature stability and mechanical properties of the material. Tungsten oxide whiskers remain stable at temperatures exceeding 1200℃, while tantalum carbide hafnium has a melting point exceeding 3000℃. Furthermore, the Ta / Hf elements form dense oxide layers such as tantalum pentoxide and hafnium dioxide, which inhibit oxygen diffusion and prevent high-temperature softening. The combined addition of these two components allows the material to maintain good mechanical properties at high temperatures. Tungsten oxide whiskers possess high strength and toughness, and through bridging and pull-out effects, they can prevent crack propagation, thus enhancing the fracture toughness and impact resistance of the cermet as a reinforcing phase. The small-particle-size tantalum carbide hafnium powder is distributed within the ceramic grain boundaries, playing a solid solution strengthening role, refining the grains, and improving the strength and hardness of the cermet. Attached Figure Description

[0018] Figure 1 This is a SEM image of the modified titanium carbonitride powder prepared in Example 1 of the present invention; Figure 2 This is a SEM image of the tungsten oxide whiskers obtained in Example 1 of the present invention. Detailed Implementation

[0019] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0020] (I) Implementation Examples Example 1 Example 1 provides a material for metal-ceramic cutting tools, which is composed of the following raw materials by weight percentage: 12wt% metal binder phase, 10wt% tungsten oxide whiskers, 5wt% tantalum carbide hafnium powder, and the balance being modified titanium carbonitride powder.

[0021] The modified titanium carbonitride powder is prepared by the following process: (1) According to the ratio of titanium carbonitride, copper nitrate, scandium nitrate and water, 1 mol: 0.1 mol: 0.04 mol: 0.8 L, copper nitrate and scandium nitrate were added to water and stirred to dissolve. Then titanium carbonitride was added and ultrasonically dispersed for 15 min to obtain a mixture. The pH of the mixture was adjusted to 9 with 18 mol / L ammonia water, and then heated at 130 °C for 10 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a solid powder. (2) Nitrogen and hydrogen are mixed at a volume ratio of 1:2. Under the mixed gas atmosphere, the solid powder from step (1) is calcined at 1300℃ for 2 hours to obtain modified titanium carbonitride. Figure 1 This is a SEM image of the modified titanium carbonitride.

[0022] Tungsten oxide whiskers are prepared by the following process: Sodium tungstate, sodium sulfide, and water were added to water at a ratio of 1 g: 9 g: 90 mL and stirred until dissolved. The pH was then adjusted to 2 using 4 mol / L hydrochloric acid. After stirring until a precipitate formed, the mixture was allowed to stand for 22 hours. The pH was then adjusted to 9 using 8 mol / L ammonia solution. Sodium sulfide was then added, and the mixture was subjected to a hydrothermal reaction at 150°C for 38 hours. After the reaction was completed, the solid was filtered off, washed, and dried to obtain tungsten oxide whiskers. Figure 2 This is a SEM image of tungsten oxide whiskers.

[0023] This embodiment also provides a method for preparing the above-mentioned material for metal-ceramic cutting tools, the specific steps of which are as follows: According to the above weight percentages, the metal binder phase, tungsten oxide whiskers, tantalum carbide hafnium powder, and modified titanium carbonitride powder were ball-milled at 200 r / min for 22 h to obtain a mixture; the mixture was pre-pressed at 250 MPa for 4 min to obtain a compact; then the compact was placed in a sintering furnace and sintered at 1300 °C for 70 min under a vacuum of 15 Pa to obtain a material for metal-ceramic cutting tools.

[0024] Example 2 Example 2 provides a material for metal-ceramic cutting tools, which is composed of the following raw materials by weight percentage: 10wt% metal binder phase, 6wt% tungsten oxide whiskers, 3wt% tantalum carbide hafnium powder, and the balance being modified titanium carbonitride powder.

[0025] The modified titanium carbonitride powder is prepared by the following process: (1) According to the ratio of titanium carbonitride, copper nitrate, scandium nitrate and water, 1 mol: 0.08 mol: 0.02 mol: 0.5 L, copper nitrate and scandium nitrate were added to water and stirred to dissolve. Then titanium carbonitride was added and ultrasonically dispersed for 10 min to obtain a mixed solution. The pH of the mixed solution was adjusted to 8.5 using ammonia water with a concentration of 15 mol / L. Then the reaction was heated at 120 °C for 10 h. After the reaction was completed, the solution was filtered, washed and dried to obtain a solid powder. (2) Nitrogen and hydrogen are mixed in a volume ratio of 1:1. Under the mixed gas atmosphere, the solid powder from step (1) is calcined at 1200°C for 2 hours to obtain modified titanium carbonitride.

[0026] Tungsten oxide whiskers are prepared by the following process: Sodium sulfide, sodium tungstate, and water were added to water at a ratio of 1g:8g:80mL and stirred to dissolve. The pH was then adjusted to 1.5 with 3mol / L hydrochloric acid and stirred until a precipitate formed. The mixture was allowed to stand for 20 hours. The pH was then adjusted to 9 with 8mol / L ammonia solution. Sodium sulfide was then added, and the mixture was subjected to a hydrothermal reaction at 140℃ for 35 hours. After the reaction was completed, the solid was filtered out, washed, and dried to obtain tungsten oxide whiskers.

[0027] This embodiment also provides a method for preparing the above-mentioned material for metal-ceramic cutting tools, the specific steps of which are as follows: According to the above weight percentages, the metal binder phase, tungsten oxide whiskers, tantalum carbide hafnium powder, and modified titanium carbonitride powder were ball-milled at 150 r / min for 20 h to obtain a mixture; the mixture was pre-pressed at 200 MPa for 2 min to obtain a compact; then the compact was placed in a sintering furnace and sintered at 1250 °C for 60 min under a vacuum of 10 Pa to obtain a material for metal-ceramic cutting tools.

[0028] Example 3 Example 3 provides a material for metal-ceramic cutting tools, which is composed of the following raw materials by weight percentage: 14wt% metal binder phase, 13wt% tungsten oxide whiskers, 8wt% tantalum carbide hafnium powder, and the balance being modified titanium carbonitride powder.

[0029] The modified titanium carbonitride powder is prepared by the following process: (1) According to the ratio of titanium carbonitride, copper nitrate, scandium nitrate and water, 1 mol: 0.15 mol: 0.06 mol: 1 L, copper nitrate and scandium nitrate were added to water and stirred to dissolve. Then titanium carbonitride was added and ultrasonically dispersed for 20 min to obtain a mixed solution. The pH of the mixed solution was adjusted to 9.5 with 20 mol / L ammonia water, and then heated at 150 °C for 12 h. After the reaction was completed, the solution was filtered, washed and dried to obtain a solid powder. (2) Nitrogen and hydrogen are mixed at a volume ratio of 1:3. Under the mixed gas atmosphere, the solid powder from step (1) is calcined at 1400°C for 3 hours to obtain modified titanium carbonitride.

[0030] Tungsten oxide whiskers are prepared by the following process: Sodium sulfide, sodium tungstate, and water were added to water at a ratio of 1g:10g:100mL and stirred until dissolved. The pH was then adjusted to 2.5 with 5mol / L hydrochloric acid and stirred until a precipitate formed. The mixture was allowed to stand for 25 hours. The pH was then adjusted to 10 with 10mol / L ammonia solution. Sodium sulfide was added, and the mixture was subjected to a hydrothermal reaction at 170℃ for 40 hours. After the reaction was completed, the solid was filtered out, washed, and dried to obtain tungsten oxide whiskers.

[0031] This embodiment also provides a method for preparing the above-mentioned material for metal-ceramic cutting tools, the specific steps of which are as follows: According to the above weight percentages, the metal binder phase, tungsten oxide whiskers, tantalum carbide hafnium powder, and modified titanium carbonitride powder were ball-milled at 250 r / min for 25 h to obtain a mixture; the mixture was pre-pressed at 300 MPa for 5 min to obtain a compact; then the compact was placed in a sintering furnace and sintered at 1550 °C for 80 min under a vacuum of 20 Pa to obtain a material for metal-ceramic cutting tools.

[0032] (ii) Comparative Example Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that the modified titanium carbonitride powder in Example 1 is replaced with titanium carbonitride.

[0033] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that the modified titanium carbonitride powder in Example 1 is replaced with a physical mixture of copper, scandium oxide and titanium carbonitride, and the molar ratio of titanium carbonitride, copper and scandium oxide is 1:0.1:0.04.

[0034] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that the tantalum carbide hafnium powder in Example 1 is replaced with tantalum carbide.

[0035] Comparative Example 4 Comparative Example 4 is basically the same as Example 1, except that the tungsten oxide whiskers in Example 1 are replaced with tungsten oxide particles.

[0036] (III) Test Examples The following performance tests were conducted on the cermet cutting tool materials prepared in Examples 1-3 and Comparative Examples 1-4.

[0037] Relative density test: The sample density is tested using the Archimedes method, and the sample density is divided by the theoretical density.

[0038] Bending strength test: The bending strength of the materials for cermet cutting tools in Examples 1-3 and Comparative Examples 1-4 was tested in accordance with JB / T12613-2016 "Test Methods for Performance of Ceramic Cutting Tool Materials". The results are shown in Table 1.

[0039] Hardness test: The hardness of the materials for cermet cutting tools in Examples 1-3 and Comparative Examples 1-4 were tested according to JB / T12613-2016 "Test Methods for Performance of Ceramic Cutting Tool Materials". The results are shown in Table 1.

[0040] Fracture toughness test: The fracture toughness of the materials for cermet cutting tools in Examples 1-3 and Comparative Examples 1-4 was tested in accordance with JB / T12613-2016 "Test Methods for Performance of Ceramic Cutting Tool Materials". The results are shown in Table 1.

[0041] High-temperature fracture toughness test: At 600℃, the fracture toughness of the materials for cermet cutting tools in Examples 1-3 and Comparative Examples 1-4 was tested according to JB / T12613-2016 "Test Methods for Performance of Ceramic Cutting Tool Materials". The results are shown in Table 1.

[0042] Table 1 Performance test results of materials for cermet cutting tools As shown in Table 1, the metal-ceramic cutting tool materials prepared in Examples 1-3 of the present invention have excellent high-temperature resistance and superior mechanical properties.

[0043] Compared to Example 1, Comparative Example 1 replaced the modified titanium carbonitride powder in Example 1 with titanium carbonitride; Comparative Example 2 replaced the modified titanium carbonitride powder in Example 1 with a physical mixture of copper, scandium oxide and titanium carbonitride; Comparative Example 3 replaced the tantalum carbide hafnium powder in Example 1 with tantalum carbide; and Comparative Example 4 replaced the tungsten oxide whiskers in Example 1 with tungsten oxide particles. The hardness, compressive strength, fracture toughness and high-temperature fracture toughness of Comparative Examples 1-4 all decreased to varying degrees. Specific analysis shows that, on the one hand, the present invention uses copper-scandium composite modified titanium carbonitride as a raw material to prepare metal-ceramic cutting tools, which can effectively improve the mechanical properties and sintering performance of the material. Copper possesses excellent ductility and softness. Scandium can form a solid solution with titanium carbonitride, inhibiting grain boundary diffusion and refining grains. The combination of these two modifies titanium carbonitride, maintaining its high hardness while delaying ceramic brittleness, improving strength and toughness, and forming a lubricating film on the material surface to reduce the coefficient of friction and further enhance wear resistance. Copper also has a low melting point and good sinterability, forming a liquid phase during sintering to promote atomic rearrangement and improve ceramic sintering performance. Scandium, as a rare earth element, adsorbs impurities and purifies grain boundaries; calcination in a nitrogen atmosphere forms a dense nitride layer, improving corrosion resistance. Furthermore, this invention adds tungsten oxide whiskers and tantalum carbide hafnium powder as reinforcing phases to the cermet, improving its high-temperature stability and mechanical properties. Tungsten oxide whiskers remain stable at temperatures exceeding 1200℃, while tantalum carbide hafnium has a melting point exceeding 3000℃. The Ta / Hf elements form dense oxide layers such as tantalum pentoxide and hafnium dioxide, which inhibit oxygen diffusion and prevent material softening at high temperatures. The combined addition of these two elements allows the material to maintain good mechanical properties at high temperatures. Furthermore, tungsten oxide whiskers possess high strength and toughness, and through bridging and pull-out effects, they can prevent crack propagation, acting as a reinforcing phase to improve the fracture toughness and impact resistance of cermets. Small-particle-size tantalum carbide hafnium powder, distributed within the ceramic grain boundaries, plays a role in solid solution strengthening, refining the grains and enhancing the strength and hardness of the cermet.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A material for metal-ceramic cutting tools, characterized in that, It is composed of the following raw materials by weight percentage: 10-14 wt% metal binder phase, 6-13 wt% tungsten oxide whiskers, 3-8 wt% tantalum carbide hafnium powder, and the balance being modified titanium carbonitride powder. The modified titanium carbonitride powder is prepared by the following process: (1) Dissolve copper salt and scandium salt in water, then add titanium carbonitride and disperse ultrasonically. Adjust the pH to 8.5-9.5 and then heat the reaction. Filter, wash and dry to obtain solid powder; (2) The solid powder is calcined in a mixed atmosphere of nitrogen and hydrogen to obtain the modified titanium carbonitride.

2. The material for metal-ceramic cutting tools according to claim 1, characterized in that, The molar ratio of titanium carbonitride, copper salt and scandium salt in step (1) is 1:(0.08-0.15):(0.02-0.06).

3. The material for metal-ceramic cutting tools according to claim 1, characterized in that, The heating reaction in step (1) is carried out at a temperature of 120-150℃ for 10-12 hours.

4. The material for metal-ceramic cutting tools according to claim 1, characterized in that, The volume ratio of nitrogen to hydrogen in step (2) is 1:1-3; the calcination temperature is 1200-1400℃ and the time is 2-3h.

5. The material for metal-ceramic cutting tools according to claim 1, characterized in that, The tungsten oxide whiskers are prepared by the following process: Sodium tungstate was dissolved in water, and the pH was adjusted to 1.5-2.

5. The mixture was stirred until a precipitate formed. The mixture was allowed to stand for 20-25 hours, and the pH was adjusted to 9-10. After stirring for another 2-5 hours, sodium sulfide was added to carry out a hydrothermal reaction. The mixture was then filtered, washed, and dried to obtain the tungsten oxide whiskers.

6. The material for metal-ceramic cutting tools according to claim 5, characterized in that, The mass ratio of sodium sulfide to sodium tungstate is 1:8-10; the hydrothermal reaction temperature is 140-170℃ and the time is 35-40h.

7. The material for metal-ceramic cutting tools according to claim 1, characterized in that, The metallic binder phase consists of equimolar amounts of Fe, Co, and Ni.

8. A method for preparing a cermet cutting tool material according to any one of claims 1-7, characterized in that, Includes the following steps: According to the stated weight percentages, the metal binder phase, tungsten oxide whiskers, tantalum carbide hafnium powder, and modified titanium carbonitride powder are ball-milled and mixed, and then pre-pressed to obtain a compact; the compact is then sintered under vacuum conditions to obtain the final product.

9. The method for preparing the material for metal-ceramic cutting tools according to claim 8, characterized in that, The pre-compression pressure is 200-300 MPa, and the time is 2-5 min; the vacuum degree of the vacuuming is 10-20 Pa.

10. The method for preparing the material for metal-ceramic cutting tools according to claim 8, characterized in that, The sintering temperature is 1250-1550℃ and the time is 60-80min.

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