High-toughness and high-compactness titanium carbonitride-based metal ceramic material and preparation method thereof

Abstract

The invention discloses a titanium carbonitride-based metal ceramic material with high toughness and high compactness, titanium carbonitride is used as a hard matrix phase, tungsten carbide is used as an additive, FeCoCrNi is used as a binding phase, the mass ratio of entropy alloy in FeCoCrNi in the metal ceramic material is 12%-30%, and the mass ratio of tungsten carbide in the metal ceramic material is 20%. The invention also provides a preparation method of the titanium carbonitride-based metal ceramic material, which comprises the following steps: carrying out primary ball-milling mixing on iron, cobalt, nickel and chromium powder to obtain medium-entropy alloy binding phase powder, carrying out secondary ball-milling mixing on titanium carbonitride, the uniformly dried medium-entropy alloy binding phase powder and tungsten carbide powder, filling into a graphite mold after mixing, and carrying out compression molding to obtain the titanium carbonitride-based metal ceramic material. And carrying out spark plasma sintering on the titanium carbonitride-based metal ceramic material to prepare the titanium carbonitride-based metal ceramic material. According to the titanium carbonitride-based metal ceramic material and the preparation method thereof, the excellent mechanical property and the good molten aluminum corrosion resistance are achieved at the same time.

Description

Technical Field

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

[0002] During the production, processing and application of aluminum and its alloys, such as aluminum smelting, casting, aluminum electrolysis, aluminum liquid transportation pipelines, etc., they are in high temperature and strong corrosive environment all year round. Traditional metal materials are very easy to react with oxygen, sulfides, and even sodium, potassium and other substances in aluminum liquid, which aggravates the corrosion process, shortens the service life of equipment, reduces production efficiency, and affects the stability and continuity of aluminum industry production. Therefore, the development of materials that can resist molten aluminum corrosion has become a research focus.

[0003] In order to deal with the problem of molten aluminum corrosion, various types of metal materials, surface modification treatments, intermetallic compounds, and inorganic non-metallic materials have been studied. Among them, modified titanium-based alloys and refractory alloys with relatively good molten aluminum resistance have complex processing processes and high costs. FeAl3, TiAl3 and other Al-containing intermetallic compounds, Al2O3, SiC and other traditional corrosion-resistant ceramics have excellent molten aluminum corrosion resistance. However, they are brittle and easy to crack. Transition metal ceramics such as TiCN not only have excellent molten aluminum resistance, high hardness and wear resistance, good chemical stability, and compared with traditional materials, their corrosion rate in aluminum liquid is lower, which can improve the service life and processing accuracy of equipment and tools. Titanium carbonitride-based metal ceramic materials have significant advantages, but there is an urgent need to improve the technical problems of difficult preparation densification and low strength and toughness. Summary of the invention

[0004] In view of the above technical problems to be solved, the present invention provides a high-toughness and high-density titanium carbonitride-based metal ceramic material and a preparation method thereof.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0006] A high-toughness and high-density titanium carbonitride-based cermet material, with titanium carbonitride as a hard matrix phase, tungsten carbide as an additive, and FeCoCrNi as a bonding phase, wherein the mass ratio of the FeCoCrNi medium-entropy alloy in the cermet material is 12%-30%, and the mass ratio of tungsten carbide in the cermet material is 20%.

[0007] As a further improvement of the above technical solution:

[0008] Preferably, the titanium carbonitride-based cermet material is composed of the following components by mass percentage: 50-68% of TiCN, 2.97%-7.43% of Fe, 3.14%-7.84% of Co, 2.77%-6.92% of Cr, 3.12%-7.81% of Ni, and 20% of WC.

[0009] Titanium carbonitride itself has high hardness and wear resistance, but is brittle and difficult to process. In the present invention, the addition of the FeCoCrNi medium-entropy alloy as a binder phase forms a liquid phase during sintering, enhancing particle wettability, accelerating mass transfer, reducing the densification temperature (from the traditional 1600-1800 °C to 1300-1500 °C), and promoting material densification; moreover, Ni and Co elements can form a plastic phase in the ceramic matrix, improving fracture toughness and playing a role in solid solution strengthening. Fe and Cr elements are mainly dissolved in the material, effectively refining the grain size of the hard phase, and the passivation reaction of Cr elements also enhances the corrosion resistance to molten aluminum and improves mechanical properties. In the present invention, tungsten carbide accounting for 20% by mass is used as an additive to the titanium carbonitride-based metal material. The introduction of tungsten carbide can be pinned at the grain boundaries of TiCN, hindering grain boundary migration, inhibiting abnormal grain growth, and realizing the Hall-Petch effect of fine grain strengthening. The fine grains can form a physical barrier, reducing the direct contact between the molten aluminum and the matrix, thereby reducing the corrosion rate. Moreover, tungsten carbide and titanium carbonitride may form a partial eutectic liquid phase at high temperatures, enhancing particle wettability, reducing the sintering temperature, and accelerating densification.

[0010] The present invention also provides a preparation method for a high-toughness and high-density titanium carbonitride-based cermet material for preparing the above-mentioned titanium carbonitride-based cermet material. First, iron, cobalt, nickel, and chromium powders are ball-milled and mixed for the first time to obtain a medium-entropy alloy binder phase powder. Then, titanium carbonitride, the dried and uniform medium-entropy alloy binder phase powder, and tungsten carbide powder are ball-milled and mixed for the second time. After mixing evenly, the powder is loaded into a graphite mold and pressed into shape, and then subjected to spark plasma sintering to obtain the titanium carbonitride-based cermet material.

[0011] As a further improvement of the above technical solution:

[0012] Preferably, the preparation method includes the following specific steps:

[0013] Step S1, add Fe, Co, Cr, Ni powders and anhydrous ethanol with a mass of 120%-150% of the powder into the ball mill tank, vacuum seal it, and use a planetary ball mill to perform the first ball milling to obtain a slurry. Put the slurry into a vacuum drying oven and dry it at a temperature of 80 °C - 85 °C for 10 h, and grind and screen it to obtain the FeCoCrNi medium-entropy alloy powder;

[0014] Step S2: Mix the medium-entropy alloy powder, TiCN powder, and WC powder. Meanwhile, prepare absolute ethanol with a mass of 120%-150% of the powder, add it to the ball mill tank, seal it under vacuum, and use a planetary ball mill for the second ball milling to obtain a slurry. Place the slurry in a vacuum drying oven and dry it at a temperature of 80°C - 85°C for 10 hours. Grind and sieve it to obtain a titanium carbonitride-based cermet mixed powder.

[0015] Step S3: After filling the mixed powder obtained in Step S2 into the mold, use a tablet press to apply a uniaxial pressure to the mold along the Y-axis direction, so that the powder coated with graphite paper is densely formed under the action of pressure.

[0016] Step S4: Place the mold filled with the powder in a sintering furnace prepared by powder metallurgy for SPS sintering; after sintering is completed, cool it to room temperature and perform demolding treatment to obtain a block-shaped ceramic product.

[0017] Preferably, after sintering, the titanium carbonitride-based cermet has a bulk density of 5.77 - 6.04 g / cm3, a relative density of 85.27% - 97.48%, and a Vickers hardness of 1670 HV - 1864 HV.

[0018] Preferably, the particle size of the TiCN powder is 3 - 5 μm, and the purity is ≥99.5%.

[0019] Preferably, the average particle size of the Fe, Co, Cr, and Ni powders is 1 - 2 μm.

[0020] Preferably, the first ball milling mixes to obtain a uniform medium-entropy alloy binder phase powder, with a ball-to-powder ratio of 10:1, a ball milling time of 48 hours, and a rotation speed of 300 r / min.

[0021] Preferably, the second ball milling mixes to obtain a uniform titanium carbonitride-based cermet, with a ball-to-powder ratio of 7:1, a ball milling time of 24 hours, and a rotation speed of 300 r / min.

[0022] Preferably, in Step S4, the SPS sintering process is as follows: the sintering temperature is 1450°C, the sintering pressure is 40 Mpa, the heating step is to heat from room temperature to 650°C in 6 minutes, then heat at a heating rate of 50 - 150°C per minute for 6 minutes to 1250°C, after heating to 1250°C, heat at a heating rate of 0 - 100°C per minute for 3 minutes to 1450°C, and keep it at this temperature for 5 minutes, and then cool it to room temperature with the furnace, maintaining a vacuum throughout the process, and the vacuum degree is 10-3 - 10-1 Pa.

[0023] The high-toughness and high-density titanium carbonitride-based cermet material and its preparation method provided by the present invention have the following advantages compared with the prior art:

[0024] (1) The high-toughness and high-density titanium carbonitride-based cermet material and its preparation method of the present invention. The ceramic phase has excellent chemical stability. The ceramic phases TiCN (titanium carbonitride) and WC (tungsten carbide) have the characteristics of high hardness, high melting point, and extremely strong chemical inertness. TiCN shows good corrosion resistance in acidic, alkaline, and oxidizing environments, while WC has high stability in non-oxidizing acids (such as hydrochloric acid and sulfuric acid). In the metal binder phase (FeCoCrNi) of the present invention, the Cr element can form a dense Cr 2 O 3 passivation film, significantly improving the resistance to pitting corrosion and uniform corrosion; Ni and Co enhance the corrosion resistance in reducing media; the synergistic anti-corrosion mechanism: the ceramic phase (TiCN / WC) acts as a hard skeleton, which can block the penetration of corrosive media; the metal phase (FeCoCrNi) protects the matrix through the passivation film, forming a double protective layer to delay the corrosion propagation. High-temperature corrosion resistance: TiCN and WC still maintain structural stability at high temperatures, while the high-temperature oxidation resistance of the FeCoCrNi alloy makes it suitable for high-temperature corrosion environments.

[0025] (2) The high-toughness and high-density titanium carbonitride-based cermet material and its preparation method of the present invention. The multi-phase composite structure inhibits corrosion propagation: The ceramic phases (TiCN, WC) and the metal phase (FeCoCrNi) are tightly combined through the interface to form a physical barrier. Corrosive media need to bypass the ceramic phase or break the interface to penetrate deep into the matrix, significantly extending the corrosion path. Uniform corrosion characteristics of the multi-principal element alloy: As a multi-principal element alloy, FeCoCrNi has a high mixing entropy effect that inhibits the formation of harmful precipitation phases and reduces the tendency of galvanic corrosion; the compositional uniformity also reduces the sensitivity to local corrosion.

[0026] (3) The high-toughness and high-density titanium carbonitride-based cermet material and its preparation method of the present invention. Low defect density and densified structure: Through an advanced sintering process, the internal porosity of the material is extremely low, reducing the penetration channels of corrosive media and improving the overall corrosion resistance. Brief Description of the Drawings

[0027] Figure 1 is the process diagram of the present invention.

[0028] Figure 2 is the microscopic SEM diagram of the titanium carbonitride-based cermet refractory aluminum corrosion-resistant material in Examples 1-3 of the present invention.

[0029] Figure 3 is the diagram of the density, theoretical and bulk density of the titanium carbonitride-based cermet refractory aluminum corrosion-resistant material in Examples 1-3 of the present invention varying with different binder contents;

[0030] Figure 4 is the diagram of the hardness of the titanium carbonitride-based cermet refractory aluminum corrosion-resistant material in Examples 1-3 of the present invention varying with different binder phase contents.

[0031] Figure 5 This is a graph showing the change in the fracture toughness of the titanium carbonitride-based cermet refractory aluminum corrosion-resistant material in Examples 1-3 of the present invention with different binder phase contents.

[0032] Figure 6 This is a scanning electron microscope image of the corrosion interface of the cermet material sample of Example 1 of the present invention after being corroded in molten aluminum at 700 °C for 1 day, 3 days, 5 days, 10 days, and 20 days.

[0033] Figure 7 This is a scanning electron microscope image of the corrosion interface of the cermet material sample of Example 2 of the present invention after being corroded in molten aluminum at 700 °C for 1 day, 3 days, 5 days, 10 days, and 20 days.

[0034] Figure 8 This is a scanning electron microscope image of the corrosion interface of the cermet material sample of Example 3 of the present invention after being corroded in molten aluminum at 700 °C for 1 day, 3 days, 5 days, 10 days, and 20 days.

[0035] Figure 9 This is a graph showing the change in the corrosion thickness of the cermet material samples of Examples 1-3 of the present invention after being corroded in molten aluminum at 700 °C for 1 day, 3 days, 5 days, 10 days, and 20 days. Detailed implementation manners

[0036] The following provides a detailed description of the specific implementation manners of the present invention. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0037] Example 1

[0038] In this example, a high-toughness and high-density titanium carbonitride-based cermet refractory aluminum corrosion-resistant material and its preparation method are provided. Specifically, TiCN-12wt.% FeCoCrNi-20wt.% WC is prepared by using spark plasma sintering technology, which specifically includes the following steps:

[0039] Step (1), powder mixing: Weigh 2.97 g of iron powder, 3.14 g of cobalt powder, 2.77 g of chromium powder, and 3.12 g of nickel powder with a purity of ≥99.5% and an average particle size of 1-2 μm purchased from the market according to mass percentages of 2.97%, 3.14%, 2.77%, and 3.12%; weigh 20.4 g of TiCN powder with a purity of ≥99.5% and an average particle size of 3-5 μm purchased from the market, and 6 g of tungsten carbide powder with a mass percentage of 20%.

[0040] Step (2), first ball milling: Load the weighed metal powder into the ball milling tank, and simultaneously add anhydrous ethanol with a mass of 100%-150% of the powder and 120 g of mixed tungsten carbide grinding balls with a ball-to-material ratio of 10:1. Then, vacuum seal and install it on a planetary vertical ball mill for ball milling. The ball milling time is 48 h, the ball milling speed is 300 r / min, and it stops rotating for 5 minutes every hour of rotation.

[0041] Step (3), first vacuum drying: Put the ball-milled slurry into a vacuum drying oven for vacuum drying. The drying temperature is 85 °C, the vacuum degree is -0.1 MPa, and the drying time is 24 h. Finally, uniformly dried FeCoCrNi medium-entropy alloy powder is obtained.

[0042] Step (4), second ball milling: Take a total of 30 g of powder, including 3.6 g of medium-entropy alloy powder, 6 g of tungsten carbide powder, and 20.4 g of titanium carbonitride powder, and load it into the ball milling tank. At the same time, add anhydrous ethanol with a mass of 100%-150% of the powder and 210 g of mixed tungsten carbide grinding balls with a ball-to-material ratio of 7:1. Then, vacuum seal and install it on a planetary vertical ball mill for ball milling. The ball milling time is 24 h, the ball milling speed is 300 r / min, and it stops rotating for 5 minutes every hour of rotation.

[0043] Step (5), second vacuum drying: Put the mixed slurry into a vacuum drying oven for vacuum drying. The drying temperature is 85 °C, the vacuum degree is -0.1 MPa, and the drying time is 24 h. Finally, uniformly dried sample powder is obtained.

[0044] Step (6), sintering: Take 30 g of the mixed powder and put it into a cylindrical graphite mold with a diameter of Ψ30 mm. Use a tablet press to pre-press the powder. After removing the upper and lower columns, the powder will not leak out, that is, the graphite paper firmly seals the powder to form an initial powder block. Then, send the mold into the furnace cavity of a spark plasma machine for sintering. The sintering process is as follows:

[0045] In the first stage, heat up from room temperature to 650 °C at a rate of 100 °C / min for 6 min, and the sintering pressure increases from 0 MPa to 15 MPa.

[0046] In the second stage, continue to heat up at a rate of 100 °C / min for 3 min, heating up to 900 °C, and the sintering pressure increases from 15 MPa to the sample sintering pressure of 40 MPa.

[0047] In the third stage, heat up at a rate of 50 °C / min for 10 min, heating up to 1400 °C, the sintering pressure is 40 Mpa, keep it warm for 5 min, and then cool it to room temperature with the furnace.

[0048] Step (7): After sintering is completed, demolding treatment is carried out. The sample in the mold is taken out, and the surface graphite paper is removed to obtain TiCN-12wt.% FeCoCrNi-20wt.% WC cermet.

[0049] Example 2

[0050] In this example, a high-toughness and high-density titanium carbonitride-based cermet refractory aluminum corrosion-resistant material and its preparation method are provided. That is, TiCN-20wt.% FeCoCrNi-20wt.% WC is prepared by using spark plasma sintering technology.

[0051] Compared with the method of Example 1, the method of Example 2 is the same in other aspects except for steps (1) and (4). In step (1) of Example 2, powder mixing: Weigh 4.95g of iron powder, 5.23g of cobalt powder, 4.61g of chromium powder, and 5.21g of nickel powder with a commercially available purity of ≥99.5% and an average particle size of 1-2μm according to mass percentages of 4.95%, 5.23%, 4.61%, and 5.21%; Weigh 18g of TiCN powder with a commercially available purity of ≥99.5% and an average particle size of 3-5μm, and 6g of tungsten carbide powder with a mass percentage of 20%.

[0052] Step (4) Second ball milling: Take a total of 30g of powder, including 6g of medium-entropy alloy powder, 6g of tungsten carbide powder, and 18g of titanium carbonitride powder, and put them into a ball milling tank. At the same time, add anhydrous ethanol with a mass of 100%-150% of the powder and 210g of mixed tungsten carbide grinding balls with a ball-to-material ratio of 7:1. Then, it is vacuum-sealed and installed on a planetary vertical ball mill for ball milling. The ball milling time is 24h, the ball milling speed is 300r / min, and it stops rotating for 5 minutes every 1 hour of rotation.

[0053] Example 3

[0054] In this example, a high-toughness and high-density titanium carbonitride-based cermet refractory aluminum corrosion-resistant material and its preparation method are provided. That is, TiCN-30wt.% FeCoCrNi-20wt.% WC is prepared by using spark plasma sintering technology.

[0055] Compared with the method of Example 1, the method of Example 3 is the same in other aspects except for steps (1) and (4), which will not be elaborated here. In step (1) of Example 3: Powder mixing: Weigh 7.43g of iron powder, 7.84g of cobalt powder, 6.92g of chromium powder, and 7.81g of nickel powder with a commercially available purity of ≥99.5% and an average particle size of 1-2μm according to mass percentages of 7.43%, 7.84%, 6.92%, and 7.81%; Weigh 15g of TiCN powder with a commercially available purity of ≥99.5% and an average particle size of 3-5μm, and 6g of tungsten carbide powder with a mass percentage of 20%;

[0056] Step (4), secondary ball milling: Take 9 g of medium-entropy alloy powder, 6 g of tungsten carbide powder, and 15 g of titanium carbonitride powder, a total of 30 g of powder, and put them into a ball mill tank. At the same time, add anhydrous ethanol with a mass of 100%-150% of the powder and 210 g of mixed tungsten carbide grinding balls with a ball-to-material ratio of 7:1. Then, vacuum-seal and install it on a planetary vertical ball mill for ball milling. The ball milling time is 24 h, the ball milling speed is 300 r / min, and it stops rotating for 5 minutes every 1 hour of rotation.

[0057] Perform performance tests on the cermet materials prepared in Examples 1-3 respectively:

[0058] (I) Apparent density test

[0059] Use the Archimedes drainage method to measure the bulk density of the ceramic sample. Its calculation formula is as follows

[0060]

[0061] where m1 is the mass (g) of the dry sample, m2 is the mass (g) of the saturated sample in water, m3 is the mass (g) of the saturated sample in air, and ρ 0 is the density of water (g / cm 3 );

[0062] The relative density (apparent density) of the material, its calculation formula is as follows:

[0063]

[0064] where D b is the bulk density (g / cm3), and ρ t is the theoretical density (g / cm3);

[0065] (II) Vickers hardness test

[0066] Use a Vickers hardness tester to perform Vickers hardness tests on the cermet materials prepared in Examples 1-3 respectively. The applied force is 98 N, and the loading time is 15 s. Five different positions are selected for measurement on each specimen. The relationship between the Vickers hardness of the cermet materials prepared in Examples 1-3 and the change in the binder phase content is as Figure 4 shown. It can be seen from Figure 4 that the Vickers hardness of the prepared cermet materials first decreases and then increases with the increase in the binder phase content.

[0067] (III) Fracture toughness test

[0068] After testing the Vickers hardness of the cermet specimen, indentations and cracks will appear on the specimen surface. Therefore, the indentation method can be used to calculate the fracture toughness of the cermet specimen. Its calculation formula is:

[0069]

[0070] Among them, KIC is the fracture toughness, P is the indentation load, a is half of the indentation diagonal, and l is the crack length measured from the indentation angle.

[0071] The variation relationship of the Vickers hardness of the cermet materials prepared in Examples 1-3 with the binder phase content is as Figure 5 shown. It can be seen from the figure that in the range where the binder phase content is 12%-20%, the fracture toughness of the cermet materials prepared with the increase of the binder phase content is improved. The fracture toughness of the titanium carbonitride-based cermet specimen prepared in Example 1 can reach 11.40 MPa·m1 / 2, making up for the deficiency of the large brittleness of the pure titanium carbonitride ceramic material and being able to be applied to industrial production.

[0072] (IV) Refractory aluminum corrosion test

[0073] The refractory aluminum corrosion resistance of the chromium boride-based cermet materials prepared in Examples 1-3 can be reflected by the thickness of the corrosion layer formed in the aluminum liquid, the thickness loss of the matrix in the aluminum liquid, and the average corrosion rate. The present invention uses the depth method to calculate the average corrosion rate v, and its calculation formula is:

[0074] v = (a - b) / 2t

[0075] Among them, a is the thickness of the specimen before corrosion, b is the thickness of the specimen after corrosion, a - b is the thickness loss of the matrix, and t is the corrosion time.

[0076] Refractory aluminum corrosion test: Before conducting the refractory aluminum corrosion test, first use a digital display vernier caliper to measure the thickness of the chromium boride-based cermet specimens of Examples 1-3. The measurement method is to measure 5 times at different positions of the specimen and then take the average value. Then put the samples after measuring the thickness into an ultrasonic cleaning machine to clean the oil stains and other impurities on the surface of the samples. Finally, place each specimen in a preheated graphite crucible containing molten aluminum liquid respectively, and then put these graphite crucibles into a pit furnace for heating. By setting the program, make the temperature in the pit furnace constant at 700 °C. Finally, take out the samples after 1 day, 3 days, 5 days, 10 days, and 20 days of corrosion respectively. Subsequently, use a wire cutting machine to cut the corroded samples along the cross-section, and then observe the cross-section of the corroded samples under a scanning electron microscope (SEM), and measure the thickness of the matrix and the thickness of the corrosion layer. The measurement method is to measure 5 times at different positions and then take the average value.

[0077] The scanning electron microscope images of the cross-sections of the cermet specimens of Examples 1-3 after being corroded in the molten aluminum liquid at 700 °C for 1 day, 3 days, 5 days, 10 days, and 20 days are respectively as Figures 6 - 8(a)-(e) as shown. It can be seen from the figure that as the corrosion time prolongs, the thickness of the corrosion layer gradually increases. Figure 6 In (a)-(e), they respectively correspond to the SEM images of the corrosion interfaces after 1 day, 3 days, 5 days, 10 days, and 20 days of corrosion. Figure 7 In (a)-(e), they respectively correspond to the SEM images of the corrosion interfaces after 1 day, 3 days, 5 days, 10 days, and 20 days of corrosion. Figure 8 In (a)-(e), they respectively correspond to the SEM images of the corrosion interfaces after 1 day, 3 days, 5 days, 10 days, and 20 days of corrosion.

[0078] The relationship between the thickness of the corrosion layer and the corrosion time of the cermet specimens in Examples 1-3 after being corroded in molten aluminum at 700 °C for 3 days, 6 days, 9 days, 12 days, and 15 days is as Figure 9 shown. From Figure 9 it can be seen that the thickness of the corrosion layer of the cermet specimen in Example 1 shows a positive correlation with different growth rates with the corrosion time, indicating that as the corrosion time prolongs, the thickness of the corrosion layer continuously increases, but the increasing amplitude slows down with the change of time, indicating that the prepared cermet specimen has good corrosion resistance to molten aluminum.

[0079] Table 1 Average corrosion rate of specimens

[0080] Sample Example 1 (TiCN - 12) Example 2 (TiCN - 20) Example 3 (TiCN - 30) Average corrosion rate <![CDATA[2.38253×10 -3 mm / h]]> <![CDATA[5.45392×10 -3 mm / h]]> <![CDATA[8.0727×10 -3 mm / h]]>

[0081] Comparative Example 1

[0082] Other conditions are the same as those in Example 3, only the sintering pressure is different. The sintering pressure used in Comparative Example 1 is 50 MPa. The sintered sample in Comparative Example 1 is not formed because the sintering pressure is too high, and part of the metal reaches the boiling point and volatilizes, causing a lot of metal to stick inside the furnace cavity and outside the mold, and the remaining sample composition decreases, making it impossible to carry out the next experiment.

[0083] Comparative Example 2

[0084] The average corrosion rate of the AlCoCrFeNi high-entropy alloy exemplified in Patent CN 109913673 A is 1.2x10-2, the average corrosion rate of cast iron is 3.0x10-1, and the average corrosion rate of 316 stainless steel is 2.2x10-1. Comparing with the present invention, it can be seen that the corrosion resistance of the titanium carbonitride-based cermet material has increased by about 200 times.

[0085] The above embodiments are only preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-toughness and high-density titanium carbonitride-based cermet material, characterized in that: Titanium carbonitride is used as a hard matrix phase, tungsten carbide is used as an additive, and FeCoCrNi is used as a bonding phase, wherein the mass ratio of the FeCoCrNi medium entropy alloy in the metal ceramic material is 12%-30%, and the mass ratio of tungsten carbide in the metal ceramic material is 20%.

2. The high-toughness and high-density titanium carbonitride-based cermet material according to claim 1, characterized in that: The titanium carbonitride-based metal ceramic material is composed of the following in terms of mass percentage: TiCN 50-68%, Fe 2.97%-7.43%, Co 3.14%-7.84%, Cr 2.77%-6.92%, Ni 3.12%-7.81%, and WC 20%.

3. A method for preparing a high-toughness and high-density titanium carbonitride-based metal ceramic material, characterized in that: For preparing the titanium carbonitride-based metal ceramic material described in claim 2, firstly, iron, cobalt, nickel and chromium powders are ball-milled for the first time to obtain medium-entropy alloy bonding phase powder, and then titanium carbonitride, dry and uniform medium-entropy alloy bonding phase powder and tungsten carbide powder are ball-milled for the second time. After mixing evenly, the powder is loaded into a graphite mold for pressing and forming, and it is subjected to spark plasma sintering to obtain the titanium carbonitride-based metal ceramic material.

4. The preparation method according to claim 3, characterized in that: The preparation method comprises the following specific steps: Step S1, adding Fe, Co, Cr, Ni powders and anhydrous ethanol with a mass percentage of 120%-150% of the powders into a ball milling jar and sealing it in vacuum, using a planetary ball mill to perform the first ball milling to obtain a slurry, placing the slurry into a vacuum drying oven at a temperature of 80° C.-85° C. and drying it for 10 hours, and grinding and sieving to obtain a FeCoCrNi medium-entropy alloy powder; Step S2, mixing the medium entropy alloy powder, TiCN powder and WC powder, preparing 120%-150% of the powder mass of anhydrous ethanol, adding the mixture into a ball mill and vacuum sealing the mixture, using a planetary ball mill for a second ball milling to obtain a slurry, placing the slurry into a vacuum drying oven at 80° C.-85° C. and drying the mixture for 10 h, grinding and sieving the mixture to obtain a titanium carbonitride-based metal ceramic mixed powder; Step S3, after the mixed powder in step S2 is filled into the mold, a uniaxial pressure is applied to the mold along the Y-axis direction by a tablet press, so that the powder coated with graphite paper is compacted under the pressure; Step S4, placing the mold filled with powder in a sintering furnace prepared by powder metallurgy for SPS sintering; After sintering, the temperature is lowered to room temperature for demoulding to obtain a bulk ceramic product.

5. The preparation method according to claim 4, characterized in that: The volume density of titanium carbonitride-based cermet after sintering is 5.77-6.04g / cm3, the density is 85.27%-97.48%, and the Vickers hardness is 1670HV- 1864HV.

6. The preparation method according to claim 4, characterized in that: The TiCN powder has a particle size of 3-5 μm and a purity of ≥99.5%.

7. The preparation method according to claim 4, characterized in that: The average particle size of the Fe, Co, Cr and Ni powders is 1 to 2 μm.

8. The preparation method according to claim 4, characterized in that: The first ball milling mixing obtains uniform medium entropy alloy bonding phase powder, the ball-to-material ratio is 10:1, the ball milling time is 48 hours, and the rotation speed is 300r / min.

9. The preparation method according to claim 4, characterized in that: The second ball milling mixing obtains uniform titanium carbonitride-based cermet, with a ball-to-material ratio of 7:1, a ball milling time of 24 hours, and a rotation speed of 300 r / min.

10. The preparation method according to claim 4, characterized in that: In step S4, the SPS sintering process is as follows: the sintering temperature is 1450°C, the sintering pressure is 40Mpa, the heating step is to heat from room temperature to 650°C for 6 minutes, then heat to 1250°C at a heating rate of 50-150°C per minute for 6 minutes, and then heat to 1250°C at a heating rate of 0-100°C per minute for 3 minutes to 1450°C, and keep warm for 5 minutes, and then cool to room temperature with the furnace, and maintain vacuum throughout the process, with a vacuum degree of 10-3-10-1Pa.

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