A wide-temperature-range max phase ceramic material and a preparation method thereof

Abstract

This invention belongs to the field of ceramic materials technology, specifically relating to a wide-temperature-range MAX phase ceramic material and its preparation method. The general chemical formula of this ceramic material is (Ti 1‑x‑y Mn x Mo y The formula is 3AlC2, where x ranges from 0.15 to 0.25, y ranges from 0.05 to 0.15, and x + y = 0.3. The preparation method includes: weighing titanium powder, manganese powder, molybdenum powder, aluminum powder, and graphite powder according to stoichiometric ratios, and adding 1-3 at.% excess aluminum powder; after ball milling, drying, and sieving, sintering is performed using a two-stage hot-pressing sintering process to obtain MAX phase ceramic materials. This invention significantly improves the structural stability, mechanical properties, and tribological properties of the material over a wide temperature range from room temperature to 1600℃ through Mo and Mn element solid solution strengthening, excess Al addition, and a two-stage gradient heating sintering process.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a wide-temperature-range MAX phase ceramic material and its preparation method. Background Technology

[0002] Since their discovery in the 1960s, MAX phase ceramics have attracted much attention due to their unique nanolayered structure. This structure combines the electrical conductivity, machinability, and thermal shock resistance of metals with the high strength, high modulus, and high temperature resistance of ceramics, showing great potential in the field of high-temperature structural materials.

[0003] However, the application of traditional MAX phase ceramics (such as Ti3AlC2) in extreme high-temperature environments is severely limited. The main technical bottleneck lies in the following: when the service temperature exceeds 1300℃, the activity of Al elements in the crystal lattice increases dramatically, easily volatilizing and reacting with oxygen to form gaseous Al2O, leading to Al depletion on the material surface and deterioration of the microstructure. Simultaneously, the resulting in-situ oxide film is usually loose and porous with poor density, unable to effectively block the internal diffusion of oxygen, resulting in a rapid decline in oxidation resistance. Furthermore, under the coupled effects of high temperature and stress, grain boundaries become weak points; grain boundary migration accelerates the precipitation of the second phase, easily inducing grain boundary slip and the nucleation and propagation of microcracks, leading to a sharp decrease in the material's high-temperature compressive strength, creep resistance, and tribological properties. These defects severely restrict the application of MAX phase ceramics in extreme environments such as hot-end components of aero-engines.

[0004] With increasingly stringent requirements for materials used in extreme environments such as hot-end components of aero-engines and high-temperature reactors in fields like aerospace and new energy equipment, developing a novel MAX phase ceramic material that can maintain structural stability and excellent mechanical and tribological properties across a wide temperature range from room temperature to ultra-high temperature has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to develop a novel MAX phase ceramic material. Through solid solution strengthening of Ti sites using Mo and Mn elements, the resulting MAX phase ceramic material maintains structural stability across a wide temperature range from room temperature to ultra-high temperatures, while also exhibiting excellent mechanical and tribological properties.

[0006] On one hand, the present invention provides a wide-temperature-range MAX phase ceramic material, wherein the general chemical formula of the ceramic material is (Ti 1-x-y Mn x Mo y )3AlC2, where the range of x is 0.15≤x≤0.25, the range of y is 0.05≤y≤0.15, and x+y=0.3.

[0007] Furthermore, in the wide-temperature-range MAX phase ceramic material, the value of x is 0.2, and the value of y is 0.1.

[0008] Secondly, a method for preparing the wide-temperature-range MAX phase ceramic material described in this invention is also provided, the method comprising the following steps:

[0009] S1. Mixing: According to (Ti) 1-x-y Mn x Mo y )3AlC2 stoichiometric ratio: Weigh out titanium powder, manganese powder, molybdenum powder, aluminum powder and graphite powder, and add 1 at.%~3 at.% excess aluminum powder to it, mix evenly to obtain mixed powder;

[0010] S2. Sintering: The mixed powder is placed in a sintering device and sintered using a two-stage hot pressing sintering process to obtain MAX phase ceramic material.

[0011] Furthermore, in the method, in step S1, the additional excess aluminum powder is 2 at.%.

[0012] Furthermore, in the method, in step S1, the mixing is achieved by ball milling, with anhydrous ethanol as the process control agent, a ball-to-material ratio of 8~10:1, a rotation speed of 280~300 rpm, and a milling time of 12~15 hours; after ball milling, the mixed powder is obtained by drying and sieving.

[0013] Furthermore, in the method, the two-stage hot-pressing sintering process specifically comprises:

[0014] First stage: Heat to 800~1000℃ at a heating rate of 15℃ / min, apply a pressure of 10~20MPa, and hold for 20~40 minutes;

[0015] Second stage: Heat to 1350~1450℃ at a heating rate of 10℃ / min, apply pressure of 30~40MPa, and hold at the temperature and pressure for 140~180 minutes.

[0016] Furthermore, in the method, in step S2, the sintering is carried out in a graphite mold, and the inner wall of the graphite mold is pretreated with a hexagonal boron nitride coating.

[0017] Furthermore, in the method, in step S2, after sintering is completed, the furnace is cooled, and the pressure is released when the temperature drops below 600°C.

[0018] Finally, the invention also provides the application of the wide-temperature-range MAX phase ceramic material in the preparation of hot-end components of aerospace engines, high-temperature wear-resistant components, or high-temperature protective coatings.

[0019] Furthermore, in the application, the material is used in a temperature range of 25°C to 1600°C.

[0020] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0021] (1) This invention introduces Mn and Mo elements to strengthen the Ti site through solid solution, effectively suppressing the volatilization of Al elements and grain boundary migration at high temperature, enhancing lattice stability, and enabling the material to maintain excellent performance in an ultra-high temperature environment of 1600℃.

[0022] (2) The present invention adopts a two-stage hot pressing sintering process combined with the addition of excessive Al powder, which effectively compensates for Al loss during the sintering process, promotes the densification process, reduces brittleness, and significantly improves the density and mechanical strength of the material.

[0023] (3) The MAX phase ceramics prepared by the present invention exhibit stable and excellent tribological properties in a wide temperature range of 25℃ to 1600℃. In particular, the coefficient of friction is significantly reduced to 0.74~0.83 in the high temperature range of 800℃~1200℃, and the wear rate is as low as 10. -4 ~10 -5 This material achieves a self-lubricating effect, overcoming the technical bottleneck of high-temperature performance degradation in traditional MAX phase materials. It provides high-performance materials for high-temperature structures / wear-resistant materials in extreme environments such as hot-end components of aero-engines, and has significant engineering application value. Detailed Implementation

[0024] The technical solution of the present invention will be described below with reference to the embodiments. However, the present invention is not limited to the following embodiments.

[0025] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments, but the embodiments are not intended to limit the present invention.

[0026] Unless otherwise specified, the experimental and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0027] Ti powder, purity >99.5%, particle size 40~45μm.

[0028] Mn powder, purity >99.5%, particle size 40~45μm.

[0029] Mo powder, purity >99.5%, particle size 40~45μm.

[0030] Al powder, purity >99.5%, particle size 5~10μm.

[0031] C powder, purity >99.9%, particle size 5~10μm.

[0032] Example 1

[0033] This example demonstrates the preparation of MAX phase ceramic materials with a wide temperature range.

[0034] According to (Ti) 0.7 Mn 0.15 Mo 0.15 The stoichiometric proportions of titanium powder (Ti), manganese powder (Mn), molybdenum powder (Mo), aluminum powder (Al), and graphite powder (C) were precisely weighed. To prevent excessive volatilization of Al during sintering, an additional 1 at.% of excess Al powder was added. The MAX phase ceramic material was prepared according to the following steps.

[0035] S1. Weigh the above-mentioned titanium powder (Ti powder), manganese powder (Mn powder), molybdenum powder (Mo powder), aluminum powder (Al powder) and graphite powder (C powder) and use a planetary ball mill with a cemented carbide grinding jar and grinding balls. Use anhydrous ethanol as the process control agent, the ball-to-material ratio is 8:1, the rotation speed is 280 rpm, and the ball milling time is 15 hours to obtain a mixed slurry.

[0036] S2. Transfer the ball-milled mixture to a vacuum drying oven and dry at 80°C for 12 hours. Pass the mixture through a 200-mesh sieve to obtain a mixed powder.

[0037] S3. Carefully load the mixed powder into a pre-treated graphite mold (the inner wall of the graphite mold is pre-treated with a hexagonal boron nitride coating). Place it in a hot press sintering furnace, evacuate to <10 Pa, and perform two-stage sintering.

[0038] First stage (reaction synthesis): The temperature is increased at a rate of 15℃ / min. When the temperature reaches 800℃, a pressure of 15MPa is applied and the temperature is maintained for 20 minutes.

[0039] Second stage (densification): Heat to the target sintering temperature of 1350℃ at a rate of 10℃ / min, apply pressure to 35 MPa, and hold at the temperature and pressure for 140 minutes.

[0040] Cooling: Cool with the furnace, and depressurize after the temperature drops below 600℃. The resulting MAX phase ceramic material is labeled as 1# MAX phase ceramic material.

[0041] Example 2

[0042] This example demonstrates the preparation of MAX phase ceramic materials.

[0043] According to (Ti) 0.7 Mn 0.2 Mo 0.1The stoichiometric proportions of titanium powder (Ti), manganese powder (Mn), molybdenum powder (Mo), aluminum powder (Al), and graphite powder (C) were precisely weighed. To prevent excessive volatilization of Al during sintering, an additional 2 at.% of excess Al powder was added. The MAX phase ceramic material was prepared according to the following steps.

[0044] S1. Weigh the above-mentioned titanium powder (Ti powder), manganese powder (Mn powder), molybdenum powder (Mo powder), aluminum powder (Al powder) and graphite powder (C powder) and use a planetary ball mill with a cemented carbide grinding jar and grinding balls. Use anhydrous ethanol as the process control agent, the ball-to-material ratio is 9:1, the rotation speed is 290 rpm, and the ball milling time is 12 hours to obtain a mixed slurry.

[0045] S2. Transfer the ball-milled mixture to a vacuum drying oven and dry at 80°C for 12 hours. Pass the mixture through a 200-mesh sieve to obtain a mixed powder.

[0046] S3. Carefully load the mixed powder into the prepared graphite mold (the inner wall of the graphite mold is pretreated with a hexagonal boron nitride coating). Place it in a hot press sintering furnace, evacuate to <10 Pa, and perform two-stage sintering.

[0047] First stage (reaction synthesis): The temperature is increased at a rate of 15℃ / min. When the temperature reaches 900℃, a pressure of 15MPa is applied and the temperature is maintained for 30 minutes.

[0048] Second stage (densification): Heat to sintering temperature of 1400℃ at a rate of 10℃ / min, apply pressure to 35MPa, and hold at the temperature and pressure for 150 minutes.

[0049] S4. Cooling: Cool with the furnace, and depressurize after the temperature drops below 600℃. The resulting MAX phase ceramic material is labeled as 2# MAX phase ceramic material.

[0050] Example 3

[0051] This example demonstrates the preparation of MAX phase ceramic materials with a wide temperature range.

[0052] According to (Ti) 0.7 Mn 0.25 Mo 0.05 The stoichiometric ratio of titanium powder (Ti), manganese powder (Mn), molybdenum powder (Mo), aluminum powder (Al), and graphite powder (C) was precisely weighed. To prevent excessive volatilization of Al during sintering, an additional 3 at.% of excess Al powder was added. The MAX phase ceramic material was prepared according to the following steps.

[0053] S1. Weigh the above-mentioned titanium powder (Ti powder), manganese powder (Mn powder), molybdenum powder (Mo powder), aluminum powder (Al powder) and graphite powder (C powder) and use a planetary ball mill with a cemented carbide grinding jar and grinding balls. Use anhydrous ethanol as the process control agent, the ball-to-material ratio is 10:1, the rotation speed is 300 rpm, and the ball milling time is 14 hours to obtain a mixed slurry.

[0054] S2. Transfer the ball-milled mixture to a vacuum drying oven and dry at 80°C for 12 hours. Pass the mixture through a 200-mesh sieve to obtain a mixed powder.

[0055] S3. Carefully load the mixed powder into a pre-treated graphite mold (the inner wall of the graphite mold is pre-treated with a hexagonal boron nitride coating). Place it in a hot press sintering furnace, evacuate to <10 Pa, and perform two-stage sintering.

[0056] First stage (reaction synthesis): The temperature is increased at a rate of 15℃ / min. When the temperature reaches 1000℃, a pressure of 15MPa is applied and the temperature is maintained for 40 minutes.

[0057] Second stage (densification): Heat to the target sintering temperature of 1450℃ at a rate of 10℃ / min, apply pressure to 35MPa, and hold at the temperature and pressure for 180 minutes.

[0058] S4. Cooling: Cool with the furnace, and depressurize after the temperature drops below 600℃. The resulting MAX phase ceramic material is labeled as 3# MAX phase ceramic material.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 2 is that Al powder was not added in excess.

[0061] According to (Ti) 0.7 Mn 0.2 Mo 0.1 Precisely weigh titanium powder (Ti powder), manganese powder (Mn powder), molybdenum powder (Mo powder), aluminum powder (Al powder), and graphite powder (C powder) according to the stoichiometric ratio of 3AlC2. Prepare MAX phase ceramic materials according to the following steps.

[0062] S1. Weigh the above-mentioned titanium powder (Ti powder), manganese powder (Mn powder), molybdenum powder (Mo powder), aluminum powder (Al powder) and graphite powder (C powder) and use a planetary ball mill with a cemented carbide grinding jar and grinding balls. Use anhydrous ethanol as the process control agent, the ball-to-material ratio is 9:1, the rotation speed is 290 rpm, and the ball milling time is 12 hours to obtain a mixed slurry.

[0063] S2. Transfer the ball-milled mixture to a vacuum drying oven and dry at 80°C for 12 hours. Pass the mixture through a 200-mesh sieve to obtain a mixed powder.

[0064] S3. Carefully load the mixed powder into the prepared graphite mold (the inner wall of the graphite mold is pretreated with a hexagonal boron nitride coating). Place it in a hot press sintering furnace, evacuate to <10 Pa, and perform two-stage sintering.

[0065] First stage (reaction synthesis): The temperature is increased at a rate of 15℃ / min. When the temperature reaches 900℃, a pressure of 15MPa is applied and the temperature is maintained for 30 minutes.

[0066] Second stage (densification): Heat to sintering temperature of 1400℃ at a rate of 10℃ / min, apply pressure to 35MPa, and hold at the temperature and pressure for 150 minutes.

[0067] S4. Cooling: Cool with the furnace, and depressurize after the temperature drops below 600℃. The resulting MAX phase ceramic material is marked as #1 contrast agent.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 2 is that the MAX phase ceramic material was prepared using a one-stage sintering process.

[0070] According to (Ti) 0.7 Mn 0.2 Mo 0.1 The stoichiometric proportions of titanium powder (Ti), manganese powder (Mn), molybdenum powder (Mo), aluminum powder (Al), and graphite powder (C) were precisely weighed. To prevent excessive volatilization of Al during sintering, an additional 2 at.% of excess Al powder was added. The MAX phase ceramic material was prepared according to the following steps.

[0071] S1. Weigh the above-mentioned titanium powder (Ti powder), manganese powder (Mn powder), molybdenum powder (Mo powder), aluminum powder (Al powder) and graphite powder (C powder) and use a planetary ball mill with a cemented carbide grinding jar and grinding balls. Use anhydrous ethanol as the process control agent, the ball-to-material ratio is 9:1, the rotation speed is 290 rpm, and the ball milling time is 12 hours to obtain a mixed slurry.

[0072] S2. Transfer the ball-milled mixture to a vacuum drying oven and dry at 80°C for 12 hours. Pass the mixture through a 200-mesh sieve to obtain a mixed powder.

[0073] S3. Carefully load the mixed powder into the prepared graphite mold (the inner wall of the graphite mold is pretreated with a hexagonal boron nitride coating). Place it in a hot press sintering furnace, evacuate to <10Pa, heat to the sintering temperature of 1400℃, apply pressure to 35MPa, and hold at that temperature and pressure for 180 minutes.

[0074] S4. Cooling: Cool with the furnace, and depressurize after the temperature drops below 600℃. The resulting MAX phase ceramic material is marked as #2 contrast agent.

[0075] Test case

[0076] This test is a wide-temperature-range tribological property test of the 1#~3# MAX phase ceramic materials prepared in Examples 1~3.

[0077] The MAX phase ceramic materials prepared in Examples 1 to 3 and the MAX phase ceramic materials prepared in Comparative Examples 1 to 2 were tested under the same conditions. The friction conditions were: load of 5N, grinding pair of Si3N4, reciprocating distance of 5mm, and frequency of 300 rpm.

[0078] Table 1. Test results of the wide-temperature-range tribological properties of MAX phase ceramic materials

[0079]

[0080] As shown in Table 1, within the ambient temperature range of 25℃ to 400℃, the MAX phase ceramic materials prepared in Examples 1 to 3 all exhibited relatively high friction coefficients (>1.0) compared to the comparative agents prepared in Comparative Examples 1 and 2. This is generally because at low temperatures, an effective lubricating film cannot be formed on the material surface, and friction is mainly characterized by abrasive wear and adhesive wear. However, the friction coefficients of the MAX phase ceramic materials prepared in Examples 1 to 3 ranged from 1.00 to 1.13, significantly lower than the friction coefficients of the comparative agents in the two comparative examples (1.21 to 1.45). This indicates that MAX phase ceramics prepared through Mo and Mn element doping, excessive Al powder addition, and sintering processes possess superior anti-friction properties even at low temperatures.

[0081] In the medium-high temperature range of 800℃ to 1200℃, the friction coefficients of the 1# to 3# MAX phase ceramic materials prepared in Examples 1 to 3 significantly decreased and stabilized at a low level of 0.74 to 0.83. This indicates that within this temperature range, an oxide layer with lubricating properties may form on the material surface, thereby achieving a self-lubricating effect. The friction coefficients of the contrast agents in Comparative Examples 1 and 2 remained high in this temperature range, with frictional dilution > 1.1, suggesting that the surface contrast agents may not have formed an effective lubricating film, or the formed lubricating film was of poor quality and unstable.

[0082] In the 1600℃ ultra-high temperature region: the friction coefficients of all samples increased, but the friction coefficients of the 1#~3# MAX phase ceramic materials prepared in Examples 1~3 were 0.81~0.89, which were still significantly lower than the friction coefficients of Comparative Examples 1 and 2 and the contrast agent prepared in Comparative Example 1, which were 0.91~0.95. This may be because the properties of the oxide film changed or partially softened at ultra-high temperatures, but the 1#~3# MAX phase ceramic materials prepared in Examples 1~3 still maintained relatively good lubrication performance.

[0083] At 1000℃ and 1200℃: the wear rate of the 1#~3# MAX phase ceramic materials prepared in Examples 1~3 was further reduced to an extremely low level of 8.13×10. -5 Up to 1.09×10 -4 The friction coefficient was approximately 50% to 75% lower than that of contrast agents 1 to 2. This further confirms the formation of the "effective lubricating oxide layer" mentioned in the friction coefficient analysis, which not only reduces friction but also inhibits material wear.

[0084] In the 1600℃ ultra-high temperature region: the wear rate of all samples increased compared to the optimal value at 1000~1200℃, indicating that the ultra-high temperature environment posed a challenge to the surface condition of the materials. However, the wear rate of the 1#~3# MAX phase ceramic materials prepared in Examples 1~3 was 1.51×10 -4 ~1.69×10 -4 The wear rate was significantly lower than that of contrast agents 1 and 2. This indicates that at an ultra-high temperature of 1600℃, the MAX phase ceramic materials 1#~3# prepared in Examples 1~3 still maintained excellent wear resistance, with a wear rate of only about 25%~30% of the comparative examples. This suggests that MAX phase ceramics prepared by optimizing the process still have higher structural stability and anti-peeling ability at extreme temperatures, either in their matrix or in the oxide film formed.

[0085] In summary, the preparation method provided by this invention can significantly improve the wide-temperature-range tribological properties of MAX phase ceramic materials, especially maintaining a low wear rate and stable oxide film structure even at ultra-high temperatures of 1600℃. Among them, (Ti 0.8 Mn 0.15 Mo 0.05 The 3AlC2 component exhibits optimal comprehensive performance through the synergistic effect of Mo and Mn solid solution strengthening and oxide film, making it suitable for extreme environments such as hot-end components of aero-engines and ultra-high temperature seals.

[0086] As described above, the basic principles, main features, and advantages of the present invention have been well described. The above embodiments and specifications are merely descriptions of preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope defined by the present invention.

Claims

1. A wide-temperature-range MAX phase ceramic material, characterized in that, The chemical general formula of the ceramic material is (Ti 1-x- y Mn x Mo y )3AlC2, wherein, the value range of x is 0.15≤x≤0.25, the value range of y is 0.05≤y≤0.15, and x+y=0.

3.

2. The wide-temperature-range MAX phase ceramic material according to claim 1, characterized in that, The value of x is 0.2, and the value of y is 0.

1.

3. A method for preparing a wide-temperature-range MAX phase ceramic material as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Mixing: According to (Ti) 1-x-y Mn x Mo y )3AlC2 stoichiometric ratio: Weigh out titanium powder, manganese powder, molybdenum powder, aluminum powder and graphite powder, and add 1 at.%~3 at.% excess aluminum powder to it, mix evenly to obtain mixed powder; S2. Sintering: The mixed powder is placed in a sintering device and sintered using a two-stage hot pressing sintering process to obtain MAX phase ceramic material.

4. The method according to claim 3, characterized in that, In step S1, the additional excess aluminum powder is 2 at.%.

5. The method according to claim 3, characterized in that, In step S1, the mixing is achieved by ball milling. During ball milling, anhydrous ethanol is used as the process control agent, the ball-to-material ratio is 8~10:1, the rotation speed is 280~300 rpm, and the ball milling time is 12~15 hours. After ball milling, the mixed powder is obtained by drying and sieving.

6. The method according to claim 3, characterized in that, The two-stage hot pressing sintering process is specifically as follows: First stage: Heat to 800~1000℃ at a heating rate of 15℃ / min, apply a pressure of 10~20 MPa, and hold for 20~40 minutes; Second stage: Heat to 1350~1450℃ at a heating rate of 10℃ / min, apply pressure of 30~40 MPa, and maintain the temperature and pressure for 140~180 minutes.

7. The method according to claim 3, characterized in that, In step S2, the sintering is carried out in a graphite mold, the inner wall of which is pretreated with a hexagonal boron nitride coating.

8. The method according to claim 3, characterized in that, In step S2, the furnace is cooled after sintering, and the pressure is released when the temperature drops below 600°C.

9. An application of the wide-temperature-range MAX phase ceramic material as described in claim 1 or 2, characterized in that, It is used in the preparation of hot-end components of aerospace engines, high-temperature wear-resistant components, or high-temperature protective coatings.

10. The application according to claim 9, characterized in that, Wide-temperature-range MAX phase ceramic materials can be used in a temperature range of 25℃ to 1600℃.

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