A carbon-nitrogen dual-phase ceramic material and a method of making the same

Abstract

The application discloses a carbon-nitrogen dual-phase ceramic material and a preparation method thereof. The raw material for preparing the carbon-nitrogen dual-phase ceramic material is composed of a non-stoichiometric compound and a transition metal carbide. y The chemical formula of the non-stoichiometric compound is MN ’ , wherein M includes Cr, V, Mo, W, Ti, Nb, Ta, Hf and Zr metal; y is a stoichiometric ratio value, and ranges from 0.3 to 1.3; the chemical formula of the transition metal carbide is MC ’ , wherein M includes Cr, V, Mo, W, Ti, Nb, Ta, Hf and Zr metal; the mass fraction of the non-stoichiometric compound is 5-95 wt.%, and the rest is the transition metal carbide. The carbon-nitrogen dual-phase ceramic material prepared by the method has a Vickers hardness of up to 18.9 GPa and a fracture toughness of up to 6.7 Mpa.m 1 / 2 , and forms a complete solid solution.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a carbon-nitrogen dual-phase ceramic material and its preparation method. Background Technology

[0002] Carbon-nitrogen dual-phase ceramics are a class of ceramic materials possessing high hardness, high wear resistance, high thermal conductivity, and high chemical stability. They combine the high hardness of carbide ceramics with the good toughness of nitride ceramics, overcoming the performance bottlenecks of single-phase ceramics. They are commonly used to manufacture components and devices for use in special environments such as high temperature, high pressure, and high corrosion, meeting the rapidly developing needs of high-tech industries such as aerospace, energy, machinery, and chemical engineering. However, due to the presence of ionic, covalent, and mixed bonds in ceramic materials, intergranular slip and dislocation movement are not easily achieved, resulting in intrinsic brittleness macroscopically. At the preparation level, the required sintering temperature is as high as 1600–2000 °C, often requiring special atmospheres and high-pressure conditions, making composition control difficult. These defects limit the reliability and stability of carbon-nitrogen dual-phase ceramics in key components of high-end equipment. Therefore, improving the intrinsic brittleness and preparation process of carbon-nitrogen dual-phase ceramics is crucial for the development of high-performance ceramics.

[0003] Zhao Zhiwei et al. optimized the process during the material preparation stage. They mixed TiNC, WC, Co, Mo2C, cemented carbide spheres, and anhydrous ethanol, and dried them to obtain mixture A. They then mixed TiNC, WC, Co, Mo2C, multi-walled carbon nanotubes, cemented carbide spheres, and anhydrous ethanol, and dried them to obtain mixture B. Mixtures A and B were added layer by layer to a mold to obtain an ABA three-layer mixture. This mixture was then subjected to spark plasma (SPS) sintering under vacuum conditions. The heating rate was 50–75 °C / min, and the temperature was raised to 1350–1500 °C for holding sintering. The heating current during holding sintering was 1700–2000 A, the sintering pressure was 25–40 MPa, and the holding time was 8–20 min, resulting in a Brinell hardness of 2061.6 kgf / mm². 2 The fracture toughness is 10.26 MPa·m. 1 / 2 A stacked Ti(C,N)-based cermet [Zhao Zhiwei et al. A stacked Ti(C,N)-based cermet and its preparation method: CN119194149A. Henan University of Technology, published on December 27, 2024]. The ABA three-layer stack assembly method can effectively reduce stress concentration between layers. However, a problem with the stacked structure design is that when using a sintering furnace with unidirectional current heating, the heating of each layer is relatively uneven during the heating process. This uneven heating can lead to a large difference in the mechanical properties of the two surfaces, placing high demands on the sintering process.

[0004] Currently, improving the toughness of ceramic materials mainly involves introducing toughening components. Dong Shun et al. mixed Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder, and carbon black in a molar ratio of 2:(2~4):(2~4):(0.5~1.5):(0.5~1.5):(5~9) and ball-milled and dried to obtain a mixed powder. The mixed powder was then heated to 1500~1600 ℃ at a heating rate of 3~5 ℃ / min under a nitrogen atmosphere, held for 1~2 h, and then cooled to room temperature at a cooling rate of 3~5 ℃ / min to obtain ceramic powder. The ceramic powder was then subjected to SPS under vacuum conditions, heated to 1800~1900 ℃ at a heating rate of 80~100 ℃ / min, sintered at a pressure of 30~40 MPa, held for 10~15 min, and then cooled to 200~300 ℃ at a cooling rate of 10~20 ℃ / min. The mixture was heated to ℃ and then allowed to cool naturally to room temperature to obtain high-entropy carbonitride ceramics with a Vickers hardness of 20.12~22.04 GPa and an elastic modulus of 479~510 GPa [Dong Shun et al. A high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio and high hardness and high elastic modulus and its preparation method: CN119977592B. Harbin Institute of Technology, published on November 28, 2025]. By adjusting the molar ratio of metal powder to carbon black, the carbon vacancy concentration of the high-entropy system can be controlled, thereby introducing nitrogen atoms. This makes it easier to control the carbon-nitrogen ratio of the ceramic powder, which is beneficial to improving the mechanical properties of high-entropy carbonitride ceramics. However, this method only adjusts the molar ratio of metal powder to carbon black, which is a single-factor control method. The preparation temperature is high, especially relying on atmospheric protection ball milling, which increases the preparation cost and is not conducive to industrial production.

[0005] Wu Hao et al. used a titanium source, a tungsten source, and metal powder. The titanium source was at least one of titanium carbonitride, titanium nitride, and titanium carbide; the tungsten source was a tungsten carbide; and the metal powder was cobalt powder or nickel powder. Weigh out titanium source (42.2–58.6 wt.%), tungsten source (11.5–25.5 wt.%), and metal powder (13.3–19.2 wt.%), and a measured amount of paraffin wax. Mix the materials by ball milling, sieving, and spray granulation to obtain a mixture. Press the mixture into a compact under 200–300 MPa pressure. Perform hydrogen-assisted deesterification at 400–600 °C and hold for 1–2 h. Then, raise the temperature to 1100–1200 °C for vacuum sintering at a vacuum degree below 5 Pa and hold for 3–6 h. Next, sequentially raise the temperature to 1460–1520 °C and lower it to 1250–1350 °C for argon-assisted micro-pressure sintering, holding for 0.5–1.5 h and 1–8 h respectively. Finally, cool the temperature to 800 °C at a cooling rate of 25–35 °C / min. After cooling in the furnace below ℃, the final material has a hardness of HRA 93.8 and a fracture toughness of 9.2 MPa·m. 1 / 2A Ti(C,N)-based cermet cutting tool material with a bending strength of 2288 MPa [Wu Hao et al. A Ti(C,N)-based cermet cutting tool material and its preparation method and application: CN117070819A, Zhuzhou Huarui Precision Tools Co., Ltd., published on November 17, 2023]. This material utilizes coarse Ti-rich carbonitride particles as the core in a black-core-gray-ring structure, and fine W-rich carbide particles as the core in a white-core-gray-ring structure. The former can give the matrix high toughness, while the latter can achieve dispersion strengthening and toughening effects. However, the preparation process is complex, and the addition of the core as the temperature increases may destroy the original component structure, thus affecting the material properties.

[0006] Guo Weiming et al. provided a dual-phase high-entropy ceramic based on microstructure control. Nanoscale carbide mixed powder and boride mixed powder were loaded into a coating machine and mixed at high speed to obtain boride powder with a carbide powder coating. The powder was then loaded into a graphite mold and subjected to SPS at 1850–2200 °C under an argon atmosphere with a density greater than 98%, a Vickers hardness of 23–26 GPa, and a fracture toughness of 5–7 MPa·m. 1 / 2 A boride / carbide dual-phase high-entropy ceramic with an electrical conductivity of 1.2~2.2 S / m and a thermal conductivity of 20~35 W / m·K. This dual-phase high-entropy ceramic uses high-entropy boride as the main phase and adds a small amount of high-entropy carbide as the second phase. It has good heating efficiency and oxidation resistance, and a long service life [Guo Weiming et al. A dual-phase high-entropy ceramic based on microstructure regulation and its preparation method and application: CN115385696B, Guangdong University of Technology, published on August 15, 2023]. However, the mechanism of the high-entropy effect in dual-phase ceramics is not explained in depth, and the preparation process of multi-component high-entropy ceramics is complex. The microstructure of dual-phase high-entropy ceramics consists of interconnected carbide phases, while the boride phase is surrounded and isolated by the carbide phases, rather than forming a monolithic phase. As the proportion of high-entropy carbide phases increases, the number of interconnected high-entropy carbide phases increases, as does the number of isolated high-entropy boride phases surrounded by carbide phases. The increased spacing between the isolated high-entropy boride phases will have a negative impact on the material properties.

[0007] In summary, while current research on the preparation of carbon-nitrogen dual-phase ceramics has achieved some breakthroughs, solving some traditional technical challenges in areas such as precise control of the carbon-nitrogen ratio and low-temperature densification, significant bottlenecks remain in achieving synergistic performance improvement. It is impossible to simultaneously achieve synergistic optimization of low sintering temperature, high density, high hardness, and high toughness. Specifically, existing technologies either suffer from insufficient precision in carbon-nitrogen ratio control and weak interfacial bonding strength, or fail to balance the strengthening of the hard phase and the toughening of the toughening phase, or are prone to denitrification and poor microstructural stability under high-temperature service environments. Therefore, the industry currently lacks a carbon-nitrogen dual-phase ceramic preparation strategy that offers controllable carbon-nitrogen ratios, tight interfacial bonding, green and efficient processes, and synergistic improvement in mechanical properties and thermal stability. Summary of the Invention

[0008] The technical problem to be solved: The intrinsic brittleness of carbon-nitrogen dual-phase ceramics leads to low fracture toughness, which has a significant impact on the reliability and stability of carbide ceramics. At the same time, due to strong covalent bonds and low diffusion coefficients, it is difficult to achieve both hardness and toughness, and sintering densification is difficult. Existing low-temperature preparation processes often sacrifice density, hardness, or process stability, and cannot achieve synergistic optimization of mechanical properties and preparation process.

[0009] To address the aforementioned technical problems, this invention provides a carbon-nitrogen dual-phase ceramic material and its preparation method.

[0010] 2. Technical Solution: A carbon-nitrogen dual-phase ceramic material, the raw materials for which it is prepared consist of non-stoichiometric compounds and transition metal carbides; The chemical formula of the non-stoichiometric compound is MN. y M includes: Cr, V, Mo, W, Ti, Nb, Ta, Hf, Zr metals; y is the stoichiometric ratio value, which ranges from 0.3 to 1.3; The chemical formula of the transition metal carbide is M. ’ C, where M ’ Including: Cr, V, Mo, W, Ti, Nb, Ta, Hf, and Zr metals; The mass fraction of non-stoichiometric compounds is 5-95 wt.%, with the balance being transition metal carbides.

[0011] Furthermore, the non-stoichiometric compound MN y It is prepared by mechanical alloying of elemental metal M powder and corresponding stoichiometric compound MN powder in a certain proportion.

[0012] Preferably, the particle size of M powder is <30 μm and the purity is >99.3%; the particle size of the stoichiometric compound MN powder and the transition metal carbide powder are both 1~3 μm and the purity is >99.5%.

[0013] Furthermore, the chemical formula of the non-stoichiometric compound is TiN. 0.3 .

[0014] Furthermore, the chemical formula of the transition metal carbide is Mo2C or ZrC.

[0015] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1, Press MN in the air y The stoichiometric ratio of elemental metal M powder and the corresponding stoichiometric ratio of compound MN powder were weighed and prepared by mechanical alloying to obtain the non-stoichiometric compound MN. y pink; S2. Preparation of composite powder: Non-stoichiometric compound MN is placed in air... y The powder and carbide powder are weighed in a certain proportion and then ball-milled and mixed. S3. Oxidation of composite powder: Oxidize the composite powder without additional oxidation or at 350 ℃ for 1~6 min. S4. Cold pressing: The composite powder is evenly loaded into the mold and cold pressed. The pressure is set to 4 MPa and the holding time is 45 s. S5. High temperature and high pressure sintering: The cold-pressed sample is loaded into the assembly module of the six-sided top press for high temperature and high pressure sintering. The sintering pressure is 3~15 GPa, the sintering temperature is 1100~2100 ℃, and the holding time is 5~90 ​​min. Then the temperature is reduced and the pressure is released to obtain the blank. S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain the carbon-nitrogen dual-phase ceramic material.

[0016] Furthermore, in S1, the ball milling speed during mechanical alloying is 300~600 r / min, the ball milling time is 2~60 h, and the ball-to-material mass ratio is 2:1~20:1.

[0017] Furthermore, during ball milling in S2, 0.2 ml / 10 g of alcohol is added as a powder dispersant. The ball milling speed is 200~600 r / min, the ball-to-material mass ratio is 2:1~20:1, and the operating mode is clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constitutes one cycle.

[0018] Furthermore, the S5 six-sided top press assembly module is an assembly cavity, with pyrophyllite on the outside and conductive steel cap, graphite gasket, graphite crucible, hBN insulating liner, and sample column in the middle hole from bottom to top.

[0019] 3. Beneficial effects: This invention utilizes transition metal carbides and transition metal non-stoichiometric compounds MN y MN was prepared from raw materials by mechanical alloying in a certain proportion. y Powder, MN y Powder and carbide powder were mixed in a certain proportion, with alcohol as the powder dispersant, and the mixing process was carried out in a ball mill jar. Oxygen was introduced into the mixed powder, and after cooling, it was pre-pressed into shape. Finally, it was subjected to high-temperature and high-pressure sintering at a pressure of 3~15 GPa, a sintering temperature of 1100~2100 ℃, and a holding time of 5~90 ​​min, achieving a Vickers hardness of up to 18.9 GPa and a fracture toughness of up to 6.7 MPa·m. 1 / 2 It is a carbon-nitrogen dual-phase ceramic material that forms a complete solid solution.

[0020] The innovation of this invention lies in the introduction of a non-stoichiometric compound MN. y On the one hand, when y < 1, anionic vacancies make atoms more prone to migration, diffusion, and rearrangement during sintering, reducing the diffusion activation energy of atoms and significantly increasing the sintering rate. When y > 1, anions in non-stoichiometric compounds can accelerate the inter-elemental solubility between transition metal carbides, forming composite carbides, effectively improving interfacial bonding strength, inhibiting the precipitation of harmful phases, and improving the hardness and toughness of the material. On the other hand, the introduction of non-stoichiometric compound phases can lock the two-phase crystal structure of carbon-nitrogen ceramics by controlling the ratio and distribution of carbon and nitrogen atoms in the lattice, effectively preventing structural degradation phenomena such as phase separation, amorphization, or secondary phase transformation in subsequent processing. In addition, the vacancies rich in non-stoichiometric compounds exist as point defects, accelerating diffusion and sintering, significantly increasing the spark plasma sintering rate, and achieving densification sintering under low temperature and high pressure. At the same time, the introduction of trace oxygen atoms into carbon-nitrogen two-phase ceramic materials can, on the one hand, occupy lattice interstices, introduce a large number of lattice defects, and significantly improve the sintering activity of the powder; on the other hand, the diffusion of oxygen atoms leads to lattice distortion, forming a defect strengthening effect. This study has enabled the preparation of high-hardness and high-toughness carbon-nitrogen dual-phase ceramic materials at relatively low temperatures, providing a new approach for the preparation of carbon-nitrogen dual-phase ceramic materials. These materials can be widely used in fields such as novel cermets, cutting tools, and abrasives. Attached Figure Description

[0021] Figure 1 Examples 1-4 correspond to TiN with different oxidation degrees 0.3 -Microstructure of Mo2C composite sintered body.

[0022] Figure 2 Examples 1-4 correspond to TiN with different oxidation degrees 0.3 XRD pattern of Mo2C composite sintered body at 1300 ℃ / 5 GPa pressure / 10 min holding time.

[0023] Figure 3 Examples 1-4 correspond to TiN with different oxidation degrees 0.3 -Hardness and toughness curves of Mo2C composite sintered body.

[0024] Figure 4 Examples 5-8 correspond to TiN with different oxidation degrees 0.3 - Microstructure of ZrC composite sintered body.

[0025] Figure 5 Examples 5-8 correspond to TiN with different oxidation degrees 0.3 XRD pattern of ZrC composite sintered body at 1300 ℃ / 5 GPa / 10 min holding time.

[0026] Figure 6 Examples 5-8 correspond to TiN with different oxidation degrees 0.3 - Hardness and toughness curves of ZrC composite sintered bodies. Detailed Implementation

[0027] The testing equipment described in this invention are all instruments used in conventional testing methods, such as X-ray diffractometer (XRD), Vickers hardness tester, apparent porosity and bulk density tester, scanning electron microscope (SEM), universal testing machine, assembled material surface and interface performance tester, and synchronous thermal analyzer, etc.

[0028] The present invention will now be described in detail with reference to the accompanying drawings.

[0029] As attached Figure 1 To be continued Figure 6 . Example 1

[0030] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min and a ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0031] S2. Preparation of composite powder: Weigh 0.285 g TiN in air. 0.3 0.215 g of Mo2C powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0032] S3. Oxidation of composite powder: The composite powder is oxidized at 350 ℃ and held for 1 min.

[0033] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0034] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0035] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -Mo2C composite sintered body.

[0036] Microstructure of sintered body as follows Figure 1 As shown in (c) to (d), the results indicate that the sintered product of this embodiment mainly exhibits two phases: one is a cubic titanium nitride phase, and the other is a close-packed hexagonal molybdenum carbide phase. Coarse grains appear on the surface, and cracks and micro-defects are present. Figure 3 The data corresponding to 1 minute shows that the Vickers hardness of the sintered block is 17.4 GPa, and the toughness is 4.9 MPa·m. 1 / 2 . Example 2

[0037] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min and a ball-to-powder mass ratio of 20:1 for 60 h.0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0038] S2. Preparation of composite powder: Weigh 0.285 g TiN in air. 0.3 0.215 g of Mo2C powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0039] S3. Oxidation of composite powder: The composite powder is oxidized at 350 ℃ and kept at that temperature for 3 min.

[0040] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0041] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0042] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -Mo2C composite sintered body.

[0043] Microstructure of sintered body as follows Figure 1 As shown in (e) to (f), the results indicate that the sintered product of this embodiment mainly exhibits two phases: one is a cubic titanium nitride phase, and the other is a hexagonal close-packed molybdenum carbide phase. The surface grains are coarser, the surface is uneven, and more cracks and defects appear. Figure 3 The data corresponding to 3 min yielded a Vickers hardness of 12.3 GPa and a toughness of 5.2 MPa·m for the sintered block. 1 / 2 . Example 3

[0044] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min and a ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0045] S2. Preparation of composite powder: Weigh 0.285 g TiN in air. 0.3 0.215 g of Mo2C powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0046] S3. Oxidation of composite powder: The composite powder is oxidized at 350 ℃ and kept at that temperature for 6 min.

[0047] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0048] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0049] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -Mo2C composite sintered body.

[0050] Microstructure of sintered body as follows Figure 1 As shown in (g)~(h), the results show that the sintered products of this embodiment mainly exhibit two phases: one is a cubic titanium nitride phase, and the other is a close-packed hexagonal molybdenum carbide phase. The surface grains are the coarsest and unevenly dispersed, with many cracks and defects. Figure 3 The data corresponding to 6 min yielded a Vickers hardness of 11.3 GPa and a toughness of 4.9 MPa·m for the sintered block. 1 / 2 . Example 4

[0051] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min and a ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0052] S2. Preparation of composite powder: Weigh 0.285 g TiN in air. 0.3 0.215 g of Mo2C powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0053] S3. Oxidation of composite powder: No additional oxidation was performed in this example.

[0054] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0055] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0056] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -Mo2C composite sintered body.

[0057] Microstructure of sintered body as follows Figure 1 As shown in (a) to (b), the results show that the sintered product of this embodiment mainly exhibits two phases: one is a cubic titanium nitride phase, and the other is a hexagonal close-packed molybdenum carbide phase. The surface morphology is dense, and the solid solution structure is complete. Figure 3 The data corresponding to 0 min yields a Vickers hardness of 18.3 GPa and a toughness of 4.0 MPa·m for the sintered block. 1 / 2 . Example 5

[0058] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min, ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0059] S2. Preparation of composite powder: Weigh 0.3325 g TiN in air. 0.3 0.178 g of ZrC powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0060] S3. Oxidation of composite powder: The composite powder is oxidized at 350 ℃ and held for 1 min.

[0061] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0062] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0063] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -ZrC composite sintered body.

[0064] Microstructure of sintered body as follows Figure 4 As shown in (b), the results indicate that the sintered product of this embodiment mainly exhibits two phases: one is a cubic titanium nitride phase, and the other is a cubic zirconium carbide phase. Surface porosity is significantly increased and its size is larger, the interparticle gaps are greatly widened, and defects are more pronounced. Figure 6The data corresponding to 1 min yields a Vickers hardness of 12.3 GPa and a toughness of 6.1 MPa·m for the sintered block. 1 / 2 . Example 6

[0065] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min, ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0066] S2. Preparation of composite powder: Weigh 0.3325 g TiN in air. 0.3 0.178 g of ZrC powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0067] S3. Oxidation of composite powder: The composite powder is oxidized at 350 ℃ and kept at that temperature for 3 min.

[0068] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0069] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0070] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -ZrC composite sintered body.

[0071] Microstructure of sintered body as follows Figure 4As shown in (c), one phase is titanium nitride with a cubic crystal system, and the other is zirconium carbide with a cubic crystal system. Numerous large-sized pores and obvious cracks appear on the surface, indicating particle agglomeration. Figure 6 The data corresponding to 3 min yielded a Vickers hardness of 10.1 GPa and a toughness of 3.8 MPa·m for the sintered block. 1 / 2 . Example 7

[0072] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min, ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0073] S2. Preparation of composite powder: Weigh 0.3325 g TiN in air. 0.3 0.178 g of ZrC powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0074] S3. Oxidation of composite powder: The composite powder is oxidized at 350 ℃ and kept at that temperature for 6 min.

[0075] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0076] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0077] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -ZrC composite sintered body.

[0078] Microstructure of sintered body as follows Figure 4 As shown in (d), one phase is titanium nitride with a cubic crystal system, and the other is zirconium carbide with a cubic crystal system. The surface pores are interconnected to form a network structure, and the grains are broken and randomly distributed, exhibiting a loose and porous appearance. Figure 6 The data corresponding to 6 min yielded a Vickers hardness of 9.3 GPa and a toughness of 4.7 MPa·m for the sintered block. 1 / 2 . Example 8

[0079] A method for preparing a carbon-nitrogen dual-phase ceramic material includes the following steps: S1. Preparation of non-stoichiometric TiN 0.3 Powder: Using Ti powder (particle size <30 μm, purity >99.3%) and TiN powder as raw materials, 16.6 g of Ti powder and 3.58 g of TiN powder were weighed in air and prepared by mechanical alloying. TiN was obtained by ball milling at 450 r / min, ball-to-powder mass ratio of 20:1 for 60 h. 0.3 Powder. TiN 0.3 Powder at a vacuum degree of 10 -1 Annealing at 600 ℃ for 30 min under Pa conditions removes impurities and stress. Commercial Mo2C powder (particle size 1~3 μm, purity >99%) is refined in a ball mill at a ball-to-powder mass ratio of 10:1 and a rotation speed of 300 r / min.

[0080] S2. Preparation of composite powder: Weigh 0.3325 g TiN in air. 0.3 0.178 g of ZrC powder was ball-milled and mixed with 0.01 ml of alcohol as a powder dispersant. The ball-to-powder mass ratio was 10:1, the ball mill speed was 300 r / min, and the operating mode was clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constituted one cycle.

[0081] S3. Oxidation of composite powder: No additional oxidation was performed in this example.

[0082] S4. Cold pressing: Take a certain amount of powder and compact it in the mold. The pressure is about 4 MPa, and the pressure is held for 45 seconds.

[0083] S5. High-Temperature and High-Pressure Sintering: The pre-pressed sample is loaded into the assembly module of a six-sided top press for high-temperature and high-pressure sintering. The sintering pressure is 5 GPa, the sintering temperature is 1300 ℃, and the holding time is 10 min. Subsequently, the sample is cooled and depressurized to obtain a blank.

[0084] S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain TiN. 0.3 -ZrC composite sintered body.

[0085] Microstructure of sintered body as follows Figure 4 As shown in (a), one phase is titanium nitride with a cubic crystal system, and the other is zirconium carbide with a cubic crystal system. The surface morphology is generally dense, with uniform particle distribution and no large-sized pores. Figure 6 The data corresponding to 0 min yields a Vickers hardness of 18.9 GPa and a toughness of 6.7 MPa·m for the sintered block. 1 / 2 .

[0086] A longitudinal comparison of Examples 1-8 revealed that oxidation time significantly affects the properties of carbon-nitrogen dual-phase ceramic materials: the unoxidized samples (Examples 4 and 8) exhibited the highest Vickers hardness. In Examples 1-4, the material hardness gradually decreased with increasing oxidation time (1 min → 3 min → 6 min), while the toughness initially increased and then decreased. This is because the increased oxidation degree of the mixed powder leads to excessive oxygen disrupting the crystal structure integrity, reducing the solid solution phase in the sintered body, and worsening interparticle bonding, thus reducing material hardness. Small-particle TiN... 0.3 Similar to green bodies, the sintered body absorbs crack propagation energy and reduces crack propagation distance, thus increasing the toughness of the sintered body. In Examples 5-8, as oxidation time increases, the material hardness gradually decreases, while the toughness first decreases and then increases. This is because the presence of ZrO2 enhances the toughness of the sintered body, resulting in higher toughness. However, as the amount of Ti oxide increases, the toughening effect of ZrO2 decreases. When the oxide content in the sintered body is high, the hard phase decreases, and the number of small particles increases. Cracks encountering the soft phase consume energy and inhibit crack propagation, thus gradually increasing the toughness. Through a horizontal comparison of Examples 1 and 5, 2 and 6, 3 and 7, 4 and 8, the type of second-phase powder has a certain impact on performance: under the same oxidation conditions, the hardness of the Mo2C system is generally higher than that of the ZrC system, indicating that Mo2C and TiN... 0.3 It exhibits superior solid solution compatibility, enabling a better synergistic enhancement of material hardness. The composite material prepared by this patent boasts a Vickers hardness of up to 18.9 GPa and a toughness of up to 6.7 MPa·m. 1 / 2 Compared to traditional ceramic sintered bodies, it achieves stable performance at a lower sintering temperature.

[0087] Although the present invention has been disclosed above with reference to preferred embodiments, these are not intended to limit the invention. Any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be defined by the scope of the claims of this application.

Claims

1. A carbon-nitrogen dual-phase ceramic material, characterized in that, The raw materials for its preparation consist of non-stoichiometric compounds and transition metal carbides; The chemical formula of the non-stoichiometric compound is MN. y M includes: Cr, V, Mo, W, Ti, Nb, Ta, Hf, Zr metals; y is the stoichiometric ratio value, which ranges from 0.3 to 1.3; The chemical formula of the transition metal carbide is M. ’ C, where M ’ Including: Cr, V, Mo, W, Ti, Nb, Ta, Hf, and Zr metals; The mass fraction of non-stoichiometric compounds is 5-95 wt.%, with the balance being transition metal carbides.

2. The carbon-nitrogen dual-phase ceramic material according to claim 1, characterized in that, The non-stoichiometric compound MN y It is prepared by mechanical alloying of elemental metal M powder and corresponding stoichiometric compound MN powder in a certain proportion.

3. The carbon-nitrogen dual-phase ceramic material according to claim 2, characterized in that, M powder has a particle size of <30 μm and a purity of >99.3%; the stoichiometric compound MN powder and transition metal carbide powder both have a particle size of 1~3 μm and a purity of >99.5%.

4. The carbon-nitrogen dual-phase ceramic material according to claim 1, characterized in that, The chemical formula of the non-stoichiometric compound is TiN. 0.3 .

5. A carbon-nitrogen dual-phase ceramic material according to claim 1, characterized in that, The chemical formula of the transition metal carbide is Mo2C or ZrC.

6. The method for preparing the carbon-nitrogen dual-phase ceramic material according to any one of claims 1-5, characterized in that, Includes the following steps: S1, Press MN in the air y The stoichiometric ratio of elemental metal M powder and the corresponding stoichiometric ratio of compound MN powder were weighed and prepared by mechanical alloying to obtain the non-stoichiometric compound MN. y pink; S2. Preparation of composite powder: Non-stoichiometric compound MN is placed in air... y The powder and carbide powder are weighed in a certain proportion and then ball-milled and mixed. S3. Oxidation of composite powder: Oxidize the composite powder without additional oxidation or at 350 ℃ for 1~6 min. S4. Cold pressing: The composite powder is evenly loaded into the mold and cold pressed. The pressure is set to 4 MPa and the holding time is 45s. S5. High temperature and high pressure sintering: The cold-pressed sample is loaded into the assembly module of the six-sided top press for high temperature and high pressure sintering. The sintering pressure is 3~15 GPa, the sintering temperature is 1100~2100 ℃, and the holding time is 5~90 ​​min. Then the temperature is reduced and the pressure is released to obtain the blank. S6. Post-processing: The prepared blank is subjected to surface grinding and deburring to obtain the carbon-nitrogen dual-phase ceramic material.

7. The method for preparing carbon-nitrogen dual-phase ceramic material according to claim 6, characterized in that, When preparing S1 using the mechanical alloying method, the ball milling speed is 300~600 r / min, the ball milling time is 2~60 h, and the ball-to-material mass ratio is 2:1~20:

1.

8. The method for preparing carbon-nitrogen dual-phase ceramic material according to claim 6, characterized in that, In S2, 0.2 ml / 10 g of alcohol is added as a powder dispersant during ball milling. The ball milling speed is 200~600 r / min, the ball-to-material mass ratio is 2:1~20:1, and the operating mode is clockwise for 1 hour, stop for 0.5 hours, and counterclockwise for 1 hour, which constitutes one cycle.

9. The method for preparing carbon-nitrogen dual-phase ceramic material according to claim 6, characterized in that, The S5 six-sided top press assembly module is an assembly cavity. Its outer side is pyrophyllite, and the middle hole contains, from bottom to top, a conductive steel cap, a graphite gasket, a graphite crucible, an hBN insulating liner, and a sample column.

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