Titanium carbonitride-based metal ceramic and preparation method thereof

Abstract

The invention discloses a titanium carbonitride-based metal ceramic, the calculation formula of the mass ratio of each component is Ti (C, N) 50WCxMo (50-x) / 4Ni (50-x) / 4Co (50-x) / 4Cr (50-x) / 4, in the formula, X represents the WC content, and the rest four elements of Mo, Ni, Co and Cr are in equal mass ratio and change along with the change of the WC content. The invention also discloses a preparation method of the titanium carbonitride-based metal ceramic, which comprises the following steps: S1, weighing according to the ratio of the raw materials, respectively putting the raw materials into a ball milling tank, and adopting absolute ethyl alcohol as a dispersion medium; continuously carrying out ball milling for 24 hours under the condition that the rotating speed is 300rpm; s2, slurry obtained through ball milling is dried, and dried powder is placed in a vacuum bag to be sealed and stored; s3, spark plasma sintering is adopted, the sintering temperature ranges from 1300 DEG C to 1500 DEG C, the sintering pressure is 35 MPa, and the heat preservation time is 10 minutes; and after sintering, the hard phase and the second kind of carbide dissolved in the liquid phase form an annular structure around the hard phase through recrystallization, so that a specific'core-ring 'microstructure of the Ti (C, N)-based metal ceramic is constructed.

Description

Technical Field

[0001] The present invention relates to the technical field of metal ceramic materials, in particular to a titanium carbonitride-based metal ceramic and a preparation method thereof. Background Art

[0002] With the rapid development of aerospace, advanced manufacturing, and other fields, traditional cemented carbides are no longer able to meet the material performance requirements of extreme operating conditions (coupled high temperature, corrosion, and wear). Ti(C,N)-based cermets, due to their combination of high hardness (TiC / TiN hard phase), good toughness (metal binder phase), and excellent high-temperature stability, show great potential in areas such as high-speed cutting tools and turbine blade coatings. However, the research and development and manufacturing of cermet tool materials still face challenges in nitrogen stability, strength, toughness, and service performance, and high-end cermet cutting tools still rely on imports from domestic companies.

[0003] like Figure 1 As shown in the figure, the typical microstructure of Ti(C,N)-based ceramics exhibits a "core-shell" structure, with hard phase particles (such as Ti(C,N) forming a core surrounded by a layer of solid solution (Ti,Hf,Mo)(C,N) or (Ti,W,Mo)(C,N)). This structure contributes to the material's improved fracture toughness. The structural formation mechanism is as follows: During high-temperature sintering, Ti(C,N) particles partially dissolve to form a liquid phase, or form a solid solution with metallic elements such as Mo and Ni to form a (Ti,Hf,Mo)(C,N) or (Ti,W,Mo)(C,N) solid solution. As the temperature decreases, the dissolved Ti(C,N) reprecipitates on the surface of the undissolved particles, forming a ring-like structure. The black core phase is composed of TiC or Ti(C,N) and may form during the initial sintering process. The ring phase is a complex carbide solid solution containing heavy elements such as W, Ta, and Mo. The inner shell typically forms during solid-state sintering, before the raw materials reach the eutectic temperature. The outer shell forms during liquid-phase sintering as a result of dissolution and reprecipitation, with the composition of the binder determining the properties of the outer shell. Therefore, the microstructure within each grain is determined by its composition.

[0004] Ti(C,N) based cermet material is a multiphase composite cemented carbide material manufactured by traditional powder metallurgy method with Ti(C,N) as hard phase, Ni and Co as binder phase, and WC, Mo2C, TaC, NbC and other transition metal carbides as additives to improve material properties. Its performance characteristics combine the high hardness and high temperature resistance of ceramics with the toughness of metals.

[0005] Due to their excellent performance, Ti(C,N)-based cermet tools have been used in high-speed dry cutting of typical materials such as carbon steel, stainless steel, and high-temperature alloys. Ti(C,N)-based cermets have the problems of low bending strength and toughness, which restricts the expansion of cermet applications. Compared with traditional WC-Co carbide tool materials, Ti(C,N)-based cermets have a more complex three-phase structure of hard core phase + hard shell phase + binder phase, which requires the hard shell phase to have good interfacial bonding ability with the hard core phase and binder phase at the same time. Research results show that during the sintering preparation process, the hard shell phase is formed by the reaction of carbide additives and Ti(C,N) particles, and it has a low interfacial mismatch with the hard core phase. However, due to the poor wettability of the existing hard shell phase and binder phase, its interface structure and bonding strength still need to be improved.

[0006] In addition, high-temperature oxidation will lead to the formation of an oxide layer on the surface of the material, which may be accompanied by volume expansion, crack initiation or interface peeling, thereby causing degradation of mechanical properties. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems, the present invention provides a titanium carbonitride-based cermet and a preparation method thereof, which improve the mechanical properties and high-temperature oxidation resistance of Co-Al-V system high-temperature alloys.

[0008] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0009] A titanium carbonitride-based cermet, the mass ratio of each component is calculated as Ti(C,N) 50 WC x Mo (50-x) / 4Ni (50-x) / 4 Co (50-x) / 4 Cr (50-x) / 4 , where X represents the WC content, and the other four elements, Mo, Ni, Co, and Cr, are in equal mass ratios and change with the change of WC content.

[0010] As a further improvement of the above technical solution:

[0011] Preferably, X is 15-30.

[0012] Preferably, the WC content is 20-25%.

[0013] The present invention also provides a method for preparing a titanium carbonitride-based cermet, comprising the following steps:

[0014] Step S1, powder preparation: weigh the raw materials according to the ratio and place them into a ball mill respectively, using anhydrous ethanol as the dispersion medium; then, install the ball mill into a planetary ball mill and continuously ball mill at a speed of 300 rpm for 24 hours;

[0015] Step S2, drying: the slurry obtained by ball milling is dried in a vacuum drying oven at a temperature of 80° C. for 80 to 140 minutes until the powder is completely dry; then, the dried powder is sieved through a 60-mesh sieve and sealed in a vacuum bag for storage;

[0016] Step S3, sintering: spark plasma sintering is adopted, the sintering temperature is 1300℃~1500℃, the sintering pressure is 35MPa, the holding time is 10 minutes, and the vacuum degree during the sintering process is controlled between 10-1Pa and 10Pa; after the sintering is completed, the hard phase and the second type of carbide dissolved in the liquid phase form a ring structure around the hard phase through recrystallization, thereby constructing the unique "core-ring" microstructure of Ti(C,N)-based metal ceramics.

[0017] As a further improvement of the above technical solution:

[0018] Preferably, the raw materials are titanium carbonitride, tungsten carbide, molybdenum powder, cobalt powder, nickel powder and chromium powder.

[0019] Preferably, the purity of the titanium carbonitride, tungsten carbide, molybdenum powder, cobalt powder, nickel powder and chromium powder is above 99%.

[0020] Preferably, the particle size of the titanium carbonitride, tungsten carbide, molybdenum powder, cobalt powder, nickel powder and chromium powder is 0.8-10 μm.

[0021] Preferably, in step S1, cemented carbide balls are used as grinding media, and the balls are weighed at a mass ratio of 8:1 to powder.

[0022] Preferably, the sintering temperature is 1370-1400°C.

[0023] The titanium carbonitride-based cermet and its preparation method provided by the present invention have the following advantages over the prior art:

[0024] The titanium carbonitride-based cermet and its preparation method of the present invention use Ti(C,N) as the main ceramic reinforcement phase, introduce Ni, Co, Cr, and Mo as metal binder phases, and use WC as an additive to prepare the Ti(C,N)-based cermet using spark plasma sintering technology. When the WC content is 20%, the hardness is up to 18.14GPa; when the WC content is 25%, the fracture toughness is the best. The wear resistance is the best; when the WC content is 15% and the sintering temperature is 1430℃, the oxidation resistance of the metal ceramic is the best, and the oxidation rate in 40h is 3.65×10 -5 g 2 cm -2 s -1 The WC content and sintering temperature can be designed according to different usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a typical microstructure of Ti(C,N)-based ceramics.

[0026] Figure 2 This is the preparation process of the Ti(C, N)-WC-MoCoNiCr metal ceramic of the present invention.

[0027] Figure 3 This is a Vickers hardness diagram of metal ceramic blocks with different WC contents used in the experimental verification of the present invention.

[0028] Figure 4 This is a Vickers hardness diagram of metal ceramic blocks at different sintering temperatures in the experimental verification of the present invention.

[0029] Figure 5 It is a fracture toughness diagram of metal ceramic blocks with different WC contents in the experimental verification of the present invention.

[0030] Figure 6 It is a fracture toughness diagram of metal ceramic blocks sintered at different temperatures in the experimental verification of the present invention.

[0031] Figure 7 It is the microstructure and element distribution diagram of the as-cast structure in the experimental verification of the present invention.

[0032] Figure 8 This is the oxidation surface and element distribution diagram of the Ti(C,N)-WC-MoCoNiCr metal ceramic sintered at 1370°C and oxidized at 900°C for 40 hours in the experimental verification of the present invention.

[0033] Figure 9 This is the oxidation surface and element distribution diagram of the Ti(C,N)-WC-MoCoNiCr metal ceramic sintered at 1400°C and oxidized at 900°C for 40 hours in the experimental verification of the present invention.

[0034] Figure 10 This is the oxidation surface and element distribution diagram of the Ti(C,N)-WC-MoCoNiCr metal ceramic sintered at 1430°C and oxidized at 900°C for 40 hours in the experimental verification of the present invention.

[0035] Figure 11 This is the oxidation cross section and element distribution diagram of the metal ceramic sintered at 1370°C and oxidized at 900°C for 40 hours in the experimental verification of the present invention.

[0036] Figure 12 This is the oxidation cross section and element distribution diagram of the metal ceramic sintered at 1400°C and oxidized at 900°C for 40 hours in the experimental verification of the present invention.

[0037] Figure 13This is the oxidation cross section and element distribution diagram of the metal ceramic sintered at 1430°C and oxidized at 900°C for 40 hours in the experimental verification of the present invention. DETAILED DESCRIPTION

[0038] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0039] Example

[0040] In the present invention, Ti(C,N)-WCMoCoNiCr metal ceramics are prepared by solid phase synthesis using titanium carbonitride, tungsten carbide and six kinds of powders such as molybdenum powder, cobalt powder, nickel powder and chromium powder. The mass ratio of each component of Ti(C,N)-WCMoCoNiCr is calculated as follows: 50 WC x Mo (50-x) / 4 Ni (50-x) / 4 Co (50-x) / 4 Cr (50-x) / 4 , where X represents the WC content, and the other four elements, Mo, Ni, Co, and Cr, are in equal mass ratios and change with the change of WC content.

[0041] In this embodiment, four groups of solid phase synthesis ceramic compositions with different WC contents are used, with 15%, 20%, 25% and 30% WC added, respectively, Ti(C,N) 50 WC 15 Mo 8.75 Ni 8.75 Co 8.75 Cr 8.75 , Ti(C,N) 50 WC 20 Mo 7.5 Ni 7.5 Co 7.5 Cr 7.5 , Ti(C,N) 50 WC 25 Mo 6.25 Ni 6.25 Co 6.25 Cr 6.25 and Ti(C,N) 50 WC 30 Mo5Ni5Co5Cr5 is numbered WC15, WC20, WC25, and WC30. The mass ratios of the oxide powders were calculated using the molar ratios of the elements. The component numbers and mass ratios are shown in Tables 1 and 2. The main raw materials prepared in this example were Ti(C,N), WC, Mo, Ni, Co, and Cr powders. The specific specifications of the powders are shown in Table 3.

[0042] Table 1 Composition of ingredients

[0043]

[0044] Table 2 Mass ratio

[0045]

[0046]

[0047] Table 3 Experimental raw materials

[0048]

[0049] The preparation method of the titanium carbonitride-based cermet in this embodiment includes the following steps:

[0050] Step S1, powder preparation: weigh the raw materials according to the ratio and place them into a ball mill respectively, using anhydrous ethanol as the dispersion medium; then, install the ball mill into a QM-3SP4 planetary ball mill and continuously ball mill for 24 hours at a rotation speed of 300 rpm.

[0051] Step S2, Drying: The milled slurry was dried in a DZF-6050 vacuum drying oven at 80°C for 80 to 140 minutes until the powder was completely dry. The dried powder was then sieved through a 60-mesh sieve and sealed in a vacuum bag for storage to prevent environmental impacts on its quality stability.

[0052] Step S3, sintering: The sintering process primarily includes the sintering method (e.g., hot pressing, pressureless sintering, spark plasma sintering), heating rate, sintering temperature, and holding time. As the sintering process progresses, the binder phase transforms into a liquid state after reaching the critical temperature for liquid-phase sintering and dissolves into the liquid phase, forming a typical Ti(C,N)-based cermet core-shell structure. The binder phase content is one of the key factors determining the upper limit of the sintering temperature for Ti(C,N)-based cermets. Typically, its content is negatively correlated with the sintering temperature.

[0053] In this embodiment, the metal ceramic block is sintered using a FHP-828 rapid hot pressing sintering furnace, and three sintering temperatures of 1370°C, 1400°C and 1430°C are selected. The sintering pressure is 35MPa and the holding time is 10 minutes. The vacuum degree during the sintering process is controlled between 10-1Pa and 10Pa. After sintering is completed, the hard phase and the second type of carbide dissolved in the liquid phase form a ring structure around the hard phase through recrystallization, thereby constructing the "core-ring" microstructure unique to Ti(C,N)-based metal ceramics. In this embodiment, in a rapid hot pressing sintering furnace, three different sintering temperatures (respectively 1370°C, 1400°C and 1430°C, all maintained at a holding time of 10 minutes) are set to prepare the block process.

[0054] Mechanical properties experimental verification

[0055] 1) Effect of WC content on Vickers hardness.

[0056] Twelve groups of Ti(C,N)-WC-MoCoNiCr metal ceramic blocks were prepared by adding different WC contents (15%, 20%, 25%, and 30%) at three different sintering temperatures, and the Vickers hardness and fracture toughness were measured using a Vickers hardness tester.

[0057] The Ti(C,N)-WC-MoCoNiCr metal ceramic block prepared by sintering at 1370℃, when the WC content increases from 15% to 30%, the Vickers hardness of the metal ceramic block first increases and then decreases. When the WC content is 20%, the Vickers hardness is the highest, which is 18.12GPa. The fracture toughness first increases and then decreases, and is the best when the WC content is 25%, reaching The Ti(C,N)-WC-MoCoNiCr metal ceramic block prepared by sintering at 1400℃, when the WC content increases from 15% to 30%, the Vickers hardness of the metal ceramic block always maintains a positive relationship. When the WC content is 30%, the Vickers hardness is the highest, which is 18.91GPa. The fracture toughness first increases and then decreases, and is the best when the WC content is 25%, reaching The Ti(C,N)-WC-MoCoNiCr metal ceramic block prepared by sintering at 1430℃, when the WC content increases from 15% to 30%, the Vickers hardness density of the metal ceramic block first increases and then decreases. When the WC content is 20%, the Vickers hardness is the highest, which is 16.06GPa. The fracture toughness first increases and then decreases, and is the best when the WC content is 25%, reaching

[0058] The WC content has a significant impact on the mechanical properties of Ti(C,N)-based cermets. The operating mechanism of this effect mainly includes the precise control of the microstructure, the optimization of the phase composition, and the strengthening of the interfacial bonding force. The three work together to improve the overall performance of the material. WC is widely used in metal-ceramic composites as a second-phase particle. Its purpose is to significantly improve the hardness and wear resistance of the material by strengthening the matrix phase. Under the sintering process, WC and the Ti(C,N) phase undergo a solid solution reaction, which not only enhances the mechanical properties of the matrix, but also effectively inhibits the excessive growth of Ti(C,N) grains. This mechanism promotes the refinement of the grain size, thereby improving the overall uniformity and density of the material. Figure 3 The trend of the Vickers hardness of metal ceramics changing with the amount of WC added is shown. Overall, with the increase of WC content, the Vickers hardness of the material shows an upward trend; after reaching a certain critical point, continuing to increase the WC content will cause the Vickers hardness to decrease. In the metal ceramic system, when the WC addition is less than 20%, it can significantly improve the sintering performance, enhance the wettability of the matrix, and promote grain refinement, while showing a significant porosity reduction effect. The refinement of grains leads to a significant increase in the contact area between the hard phase and the metal matrix, thereby improving the continuity of the bonding phase and shortening the mean free path between atoms. These factors together lead to an increase in the hardness of the metal ceramic material.

[0059] 2) Effect of WC content on fracture toughness.

[0060] Figure 5 It is the trend of the fracture toughness of metal ceramics with the addition of WC. When the WC content increases from 15% to 20%, the fracture toughness of metal ceramics decreases. This is because the increase in WC content causes the shell phase to become thicker and more brittle. The deformation of the grains after coarsening makes it easy for the internal stress to be concentrated in one place, causing brittle fracture. Therefore, the fracture toughness K IC When the WC content increases from 20% to 25%, the interface bonding between the hard phase and the binder phase is improved to a certain extent, thus increasing the fracture toughness. When the WC content increases from 25% to 30%, the fracture toughness decreases. This is because a harmful brittle second phase is generated, resulting in increased brittleness and decreased toughness.

[0061] When the WC content is 25%, the fracture toughness of the cermet reaches the optimal value As the WC content increases from 15% to 20%, the fracture toughness of the cermet decreases. When the WC content increases from 20% to 25%, the wettability between the ceramic phase and the binder phase of the cermet improves, leading to an increase in fracture toughness. However, when the WC content increases from 25% to 30%, the fracture toughness decreases again.

[0062] 3) Effect of sintering temperature on Vickers hardness.

[0063] from Figure 4 It can be seen that the sintering temperature has a significant effect on the hardness of Ti(C,N)-WC-MoCoNiCr cermets. As the sintering temperature increases, the Vickers hardness first increases slowly and then drops sharply. This is because within the appropriate temperature range, the temperature increase can promote particle diffusion and liquid phase formation (such as melting of the metal bonding phase), improve density, reduce pores, achieve uniform grain growth, and refine grains. At the same time, high temperature may cause Ti(C,N) to form a solid solution with WC, or react with the bonding phase metal to generate new phases. These phase changes may enhance solid solution strengthening or interfacial bonding, thereby improving the Vickers hardness. As the temperature continues to rise, it may cause the bonding phase to flow excessively or volatilize, which in turn introduces pores or composition segregation and reduces density. Excessively high temperatures will cause grain coarsening, resulting in a decrease in Vickers hardness and may also trigger crack propagation. Therefore, the sintering temperature used in the present invention is 1300℃~1500℃.

[0064] 4) Effect of sintering temperature on fracture toughness.

[0065] Figure 6 The effect of sintering temperature on the fracture toughness (K IC ). In the sintering temperature range of 1370℃ to 1400℃, the fracture toughness of cermets with different WC contents does not change much, indicating that in this temperature range, the sintering temperature has little effect on the fracture toughness K IC However, when the sintering temperature is increased to 1430℃, the fracture toughness K IC This is mainly attributed to the fact that the higher sintering temperature promotes the growth of hard phase particles, so that the crack is affected by the cutting and bypassing mechanisms during the expansion process, thereby effectively hindering the crack expansion and improving the fracture toughness K of the material. IC .

[0066] In the sintering temperature range of 1370~1400℃, the K of Ti(C,N) based cermets with different WC contents IC The value fluctuation is not obvious, and the fracture toughness K IC It is almost unaffected by the sintering temperature. When the sintering temperature is increased to 1430℃, the fracture toughness K IC Reached the peak value of

[0067] The titanium carbonitride-based cermet and its preparation method of the present invention have a maximum Vickers hardness of 18.14 GPa when the WC content is 20% and the sintering temperature is 1400°C; the fracture toughness is best when the WC content is 25% and the sintering temperature is 1430°C.

[0068] Oxidation performance experimental verification

[0069] Figure 7 It is the micromorphology and element distribution of the cast structure. Figure 8 、 Figure 9 、 Figure 10 Ti(C,N)-WC sintered at 1370℃, 1400℃, and 1430℃ respectively X -Surface morphology and element distribution of MoNiCoCr (x = 0.15, 0.2, 0.25, 0.3) metal ceramics after oxidation at 900℃ for 40h. All metal ceramics are covered with oxide scale, and no obvious surface peeling area is found. It can be clearly observed that the oxidation products have great differences in morphology. The enrichment state of the oxide can be roughly observed based on the distribution of various elements on the surface of the metal ceramics after oxidation.

[0070] according to Figures 8 to 11Analysis reveals that after oxidation at 900°C for 40 hours, the surface morphology of the WC15 sample reveals a relatively dense oxide layer with no apparent spalling. Elemental distribution analysis reveals that Ti is primarily distributed in the outer layers of the oxide layer, forming TiO2 as the primary protective oxide. W and Mo are relatively uniformly distributed, with no distinct enrichment zones, indicating that their oxidation products are well distributed within the oxide layer. This uniform elemental distribution contributes to the formation of a stable oxide layer, effectively protecting the substrate from further oxidation. The surface morphology of the oxidized WC20 sample reveals a decrease in the uniformity of the oxide layer, with the appearance of some microcracks and small areas of spalling. Elemental distribution analysis reveals that Ti remains primarily distributed in the outer layers of the oxide layer, but the continuity of the TiO2 is somewhat compromised. Ni is more prominent in the middle region of the oxide layer, while W and Mo begin to show localized enrichment, particularly in this region. This element enrichment increases the local brittleness of the oxide layer, leading to microcracks and spalling. Observation reveals that the uniformity and integrity of the oxide layer in the WC25 sample further deteriorates, with distinct areas of cracking and spalling appearing. Elemental distribution analysis shows that while Ti remains concentrated in the outer layers of the oxide layer, the continuity of the TiO2 layer is significantly reduced. Ni is more concentrated in the middle region of the oxide layer, while W and Mo are significantly enriched in the middle and outer regions. This enrichment significantly increases the local brittleness of the oxide layer, leading to more pronounced crack propagation and spalling, exposing more matrix material and accelerating the oxidation process. When the WC content increases to 30%, the uniformity and integrity of the oxide layer deteriorate to the point of extreme deterioration, with extensive spalling and severe cracking. Elemental distribution analysis shows that Ti remains concentrated in the outer layers of the oxide layer, but the continuity of the TiO2 layer is almost completely lost. Ni is more prominent in the middle region of the oxide layer, while W and Mo are significantly enriched in the outer layers. This enrichment leads to a significant increase in the brittleness of the oxide layer, severe spalling, and exposure of a large amount of matrix material, further accelerating the oxidation process.

[0071] Figures 11 to 13The cross-sectional micromorphology and element distribution of the metal ceramic after 40 hours of oxidation treatment at 900 ° C are presented. As shown in the graph, it is observed that during the oxidation process, the surfaces of WC15 specimens, WC20 specimens, WC25 specimens and WC30 specimens all show a titanium-rich structural layer. The emergence of this phenomenon is attributed to the difference in the composition of different specimens, which leads to the inconsistency of the thickness of the titanium layer. In the material system, there is a clear boundary feature between the titanium Ti-rich structural layer and the Ni and Co-rich structural layer. The element distribution in these two specific areas shows a complementary pattern, that is, the Ti-rich area is relatively poor in Ni and Co, while the Ni and Co-rich areas have a corresponding reduction in the concentration of Ti. This complementary distribution pattern may reflect the element distribution mechanism during the material synthesis process or the influence of subsequent processing. According to Figure 13 EDS spectra analysis, combined with the XRD diffraction patterns of the 40-h oxidized cermet sample previously reported, reveal that the outer oxidized layer is primarily composed of Ti oxide, TiO₂. This is due to the lower oxide formation energy of Ti, making it more susceptible to oxidation than other elements. Notably, the oxide layer thickens significantly with increasing WC content. When the WC content reaches 30%, the oxide layer exhibits significant cracking and flaking, indicating that the TiO₂ film fails to effectively protect the sample. Oxygen continues to penetrate the sample, creating pores and subsequently cracking the oxide layer. Combined with oxidation kinetic analysis, it can be concluded that the WC15 cermet exhibits the best oxidation resistance, which decreases with increasing WC content. Furthermore, sintering temperature also influences the oxidation resistance of the cermet material. As the sintering temperature increases, the oxidation resistance of the cermet sample initially weakens and then increases, with the cermet block sintered at 1430°C exhibiting the best oxidation resistance.

[0072] After 40 hours of oxidation, the four groups of cermet samples with different compositions all conform to the parabolic oxidation kinetics law. The four main oxides appearing during the oxidation process are (Ni, Co) WO4, NiCO3, TiO2, and CrO3. When the WC content is 15% and the sintering temperature is 1430℃, the cermet has the best oxidation resistance, with an oxidation rate of 3.65×10 -5 g 2 cm -2 s -1 When the WC content increases to 30%, the oxide scale begins to peel off in large quantities.

[0073] The above examples are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, they are not intended to limit the present invention. Therefore, any simple modifications, equivalent variations, and modifications to the above examples that do not depart from the technical solution of the present invention and are based on the technical essence of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A titanium carbonitride-based cermet, characterized in that: The formula for calculating the mass ratio of each component is Ti(C,N) 50 WC x Mo (50-x) / 4 Ni (50-x) / 4 Co (50-x) / 4 Cr (50-x) / 4 , where X represents the WC content, and the other four elements, Mo, Ni, Co, and Cr, are in equal mass ratios and change with the change of WC content.

2. The titanium carbonitride-based cermet according to claim 1, characterized in that: The X is 15-30.

3. The titanium carbonitride-based cermet according to claim 1, characterized in that: The WC content is 20-25%.

4. A method for preparing a titanium carbonitride-based cermet, characterized in that: The method for preparing the titanium carbonitride-based cermet according to any one of claims 1 to 3 comprises the following steps: Step S1, powder preparation: weigh the raw materials according to the ratio and place them into a ball mill respectively, using anhydrous ethanol as the dispersion medium; then, install the ball mill into a planetary ball mill and continuously ball mill at a speed of 300 rpm for 24 hours; Step S2, drying: the slurry obtained by ball milling is dried in a vacuum drying oven at a temperature of 80° C. for 80 to 140 minutes until the powder is completely dry; the dried powder is sieved through a 60-mesh sieve and sealed in a vacuum bag for storage; Step S3, sintering: spark plasma sintering is adopted, the sintering temperature is 1300℃~1500℃, the sintering pressure is 35MPa, the holding time is 10 minutes, and the vacuum degree during the sintering process is controlled between 10-1Pa and 10Pa; after the sintering is completed, the hard phase and the second type of carbide dissolved in the liquid phase form a ring structure around the hard phase through recrystallization, thereby constructing the unique "core-ring" microstructure of Ti(C,N)-based metal ceramics.

5. The preparation method according to claim 4, characterized in that The raw materials are titanium carbonitride, tungsten carbide, molybdenum powder, cobalt powder, nickel powder and chromium powder.

6. The preparation method according to claim 4, characterized in that The purity of the titanium carbonitride, tungsten carbide, molybdenum powder, cobalt powder, nickel powder and chromium powder is above 99%.

7. The preparation method according to claim 4, characterized in that The particle sizes of the titanium carbonitride, tungsten carbide, molybdenum powder, cobalt powder, nickel powder and chromium powder are 0.8-10 μm.

8. The preparation method according to claim 4, characterized in that In step S1, cemented carbide balls are used as grinding media, and the balls are weighed at a mass ratio of 8:1 to powder.

9. The preparation method according to claim 4, characterized in that The sintering temperature is 1370-1400°C.

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