Cr-ti-v based out-of-plane ordered max phase ceramic material and applications thereof

Abstract

The application discloses a Cr-Ti-V-based out-of-plane ordered MAX phase ceramic material and application thereof. The ceramic material takes Cr2TiAlC2 as a matrix, is prepared by controlling a solid solution amount of V elements to partially replace Ti elements, and has a chemical formula of Cr2(Ti 1‑x V x )AlC2; wherein 0

Description

Technical Field

[0001] This invention relates to the field of braking materials technology, and in particular to a Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material and its applications. Background Technology

[0002] Braking materials play an irreplaceable role in ensuring braking performance, maintaining driving safety, and enhancing the driving experience. High-performance braking materials, as stable and reliable friction energy dissipation components, dissipate vehicle kinetic energy by converting it into frictional heat, making them a key option for efficient deceleration and safe parking. However, during high-intensity or continuous braking operations that result in high temperatures, these temperatures can cause severe performance degradation in brake friction pairs, such as brake pads and brake discs. This degradation involves various physicochemical processes, such as the thermal decomposition of organic binders, softening and vitrification of the friction material surface layer, and oxidation of the friction film components. These high-temperature degradation effects lead to a sharp decrease in the coefficient of friction of the braking materials (thermal fade), resulting in a catastrophic decline in braking performance and seriously threatening vehicle driving safety.

[0003] The key to solving the thermal degradation problem of brake materials lies in suppressing their thermal deterioration. For example, powder metallurgy composite materials are selected to avoid the use of organic binders, high-hardness and high-melting-point ceramic materials are chosen to reduce the risk of softening, and the thermal conductivity of brake materials is enhanced to prevent heat accumulation. Among these, the preferred high-performance brake materials currently in service are carbon-ceramic systems primarily composed of carbon and silicon carbide (C / C, C / C-SiC) reinforced with carbon fibers. However, due to the oxidation loss of carbon materials and the glass transition problem of Si oxides, the thermal degradation problem of these materials at high temperatures has not yet been fundamentally solved.

[0004] Layered MAX phase ceramics are a new type of ceramic material that combines the high-temperature resistance and oxidation resistance of ceramics with the ductility and toughness of metals. Their grains can undergo interlaminar shear sliding at the friction interface, forming a surface oxide film, which shows great promise for applications in braking and solid lubrication. However, some common Ti-based MAX phase ceramics reported so far, such as Ti3AlC2 and Ti3SiC2, are usually only added as solid lubricant phases in braking materials due to their low interlaminar shear strength. Reference 1: Du CF, Xue YQ, Zeng QY, Wang JJ, Zhao XY, Wang Z, et al. Mo-doped Cr-Ti-Mo Ternary-MAX with Ultra-low Wear at Elevated Temperatures. J Eur Ceram Soc. 2022;42:7403-7413. This paper discloses a MAX ceramic material containing Cr-Ti-Mo based ternary transition metal. The incorporation of Mo allows it to still exhibit an out-of-plane chemically ordered structure and significantly reduces the wear rate at 800℃. However, because Mo forms a lubricating phase at high temperatures, the friction coefficient of the material decreases at high temperatures, resulting in poor braking performance and making it unsuitable for braking applications. Reference 2: Du C, Wang C, Liang H, et al., In-situ liquid lubrication with bearing effect on a semi-out-of-plane ordered ternary (TiVCr)3AlC2MAX at 800 ºC. Journal of the European Ceramic Society, 2023. 43(16): 7341-7353. This paper discloses a MAX ceramic material containing Cr-Ti-V ternary transition metals and its tribological properties. However, the out-of-plane order of the three transition metals in this material is disrupted, resulting in a severe loss of elastic modulus. Furthermore, the introduction of V leads to the formation of a large amount of low-melting-point V2O5 at high temperatures, causing the coefficient of friction to decrease above 400℃, thus making it difficult to apply in the braking field. Summary of the Invention

[0005] To address the problem of decreased friction coefficient in existing MAX phase ceramic materials under high-temperature conditions, leading to brake instability, this invention provides an out-of-plane ordered MAX phase ceramic material based on a Cr-Ti-V matrix. This ceramic material exhibits a significantly improved friction coefficient at high temperatures and maintains long-term stability.

[0006] The Cr-Ti-V out-of-plane ordered MAX phase ceramic material provided by this invention is prepared by controllable solid solution of V element to partially replace Ti element, using Cr2TiAlC2 as the matrix. The resulting ceramic material exhibits sublattice out-of-plane ordered characteristics of the transition metal elements; its chemical formula is as follows: Cr2(Ti 1-x V x AlC2; where 0 < x ≤0.5.

[0007] The preparation method of the Cr-Ti-V out-of-plane ordered MAX phase ceramic material is as follows: Using Cr, Ti, V, Al, and C powders as raw materials, the mixtures were ball-milled and then hot-pressed under an inert atmosphere. The hot-pressing conditions were: pressure 5 MPa to 20 MPa, temperature 1300℃ to 1500℃, and time 60 min to 180 min, to obtain Cr-Ti-V out-of-plane ordered MAX phase ceramic materials.

[0008] The purity of the raw materials Cr, Ti, V, Al, and C powders is ≥99%.

[0009] The ball milling process is performed intermittently. This process ensures that the powders of each element are mixed evenly and prevents them from sticking together due to excessively high temperatures.

[0010] The specific operation of hot pressing sintering is as follows: The ball-milled mixed powder was loaded into a graphite mold and placed in a high-temperature tube furnace. Hot pressing sintering was carried out under an argon atmosphere. The hot pressing sintering conditions were: pressure 5 MPa~20 MPa, temperature 1300℃~1500℃, and time 60 min~180 min, to obtain Cr-Ti-V out-of-plane ordered MAX phase ceramic material.

[0011] The Cr-Ti-V out-of-plane ordered MAX phase ceramic material of this invention is used to prepare braking materials. The braking material is used in an atmospheric environment ranging from room temperature to 800°C. It exhibits excellent tribological properties in this range, effectively solving the problem of reduced friction coefficients in existing materials at high temperatures, leading to brake runaway.

[0012] Compared with the prior art, the advantages of the present invention are: (1) This invention uses Cr2TiAlC2 as the matrix and uses V to replace Ti elements in an equimolar proportion to prepare Cr-Ti-V matrix out-of-plane ordered MAX phase ceramic materials with solid solution V. In existing MAX phase ceramic materials, the dissolution of V is an effective means to reduce the friction coefficient of the material. For example, in (TiVCr)3AlC2 of Reference 2, the introduction of solid solution V elements causes the formation of V2O5 lubricating phase at 800℃, resulting in a sharp drop in the friction coefficient. V elements mainly play a lubricating role. In contrast, this invention, by controlling the proportion of V added, found that the limited introduction of V elements not only allows the ceramic transition metal elements to retain the sublattice out-of-plane ordered characteristics, but also has less solid solution V compared to (TiVCr)3AlC2. Due to the synergistic effect of V with Cr and Ti elements, it promotes the formation of high-melting-point rutile phase at high temperature, thereby controlling the composition of the oxide film of the ceramic material at high temperature, so that the ceramic material has a high and stable friction coefficient and excellent wear resistance at high temperature.

[0013] (2) Compared with existing braking materials, the Cr-Ti-V out-of-plane ordered MAX phase ceramic material of the present invention has good tribological properties under atmospheric conditions from room temperature to 800℃, and the friction coefficient is higher and more stable at 800℃ than at room temperature, which effectively solves the problem of reduced friction coefficient and brake runaway of existing materials at high temperature.

[0014] (3) The composition of the Cr-Ti-V out-of-plane ordered MAX phase ceramic material of the present invention is easy to control, the required raw material powder is easy to obtain, and all of them are commercially available raw materials. The preparation process is simple and efficient, and can be further realized for large-scale industrial production.

[0015] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0016] Figure 1 The X-ray diffraction patterns are those of the MAX phase ceramic materials obtained in Examples 1-5 and Comparative Examples 1 and 2.

[0017] Figure 2 The crystal axis parameters of the MAX phase ceramic materials obtained in Examples 1-5 and Comparative Example 1 are as follows. a shaft and c Curve showing the change of shaft content with V content.

[0018] Figure 3These are scanning electron microscope (SEM) backscattering (SEM) images and EDS elemental distribution maps of the MAX phase ceramic materials of Examples 1-5 and Comparative Example 1. Among them, (a) is the SEM backscattering and EDS elemental distribution map of the MAX phase ceramic material of Comparative Example 1; (b) to (f) are the SEM backscattering and EDS elemental distribution maps of the Cr-Ti-V out-of-plane ordered MAX phase ceramic materials obtained in Examples 1-5.

[0019] Figure 4 The image shows aberration-corrected transmission electron microscope (TEM) image of the MAX phase ceramic material prepared in Example 5.

[0020] Figure 5 The images show scanning electron microscope (SEM) images of the surface of the MAX phase ceramic materials obtained in Examples 1-5 and Comparative Example 1 after friction tests at room temperature (a) and 800°C (b).

[0021] Figure 6 The graphs show the tribological performance test results of the MAX phase ceramic materials obtained in Examples 1-5 and Comparative Examples 1 and 2. Specifically, (a) is the friction coefficient-time graph for Examples 1-5 at room temperature; (b) is the friction coefficient-time graph for Examples 1-5 at 800°C; (c) is the average friction coefficient graph for the materials of Examples 1-5 and Comparative Examples 1 and 2 at room temperature and 800°C; and (d) is the average wear rate graph for the materials of Examples 1-5 and Comparative Examples 1 and 2 at room temperature and 800°C. Detailed Implementation

[0022] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0023] Example 1 A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, with the chemical formula Cr2(Ti 0.9 V 0.1 AlC2. The preparation steps are as follows: Step 1: Using commercially available Cr powder, Ti powder, V powder, Al powder, and C powder as raw materials, the ingredients are stoichiometrically prepared according to a molar ratio of Cr powder, Ti powder, V powder, Al powder, and C powder of 2:0.9:0.1:1.2:1.9. The proportion of C powder was slightly reduced and the proportion of Al powder was increased. This is mainly because a graphite mold is used for sintering, which introduces additional C; and Al will volatilize at high temperatures and react with the graphite mold, so some Al powder needs to be added to avoid Al deficiency.

[0024] Step 2: Place the prepared raw material powder in a ball mill jar and ball mill twice, each time for 30 minutes, with a 30-minute interval; to obtain a mixed powder.

[0025] Step 3: The uniformly mixed powder from the ball mill is placed in a glove box under an argon atmosphere and then loaded into a graphite mold. The mold is then placed in a high-temperature tube furnace for hot pressing sintering at a pressure of 15 MPa, a temperature of 1380℃, and a holding time of 180 min, thus preparing the Cr-Ti-V out-of-plane ordered MAX phase ceramic material Cr2(Ti 0.9 V 0.1 )AlC2.

[0026] Example 2 A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, with the chemical formula Cr2(Ti 0.8 V 0.2 AlC2. The preparation steps are as follows: Step 1: Using commercially available Cr powder, Ti powder, V powder, Al powder and C powder as raw materials, the ingredients are prepared according to the chemical metric ratio of Cr powder, Ti powder, V powder, Al powder and C powder as 2:0.8:0.2:1.3:1.9.

[0027] Steps 2 and 3 are the same as in Example 1.

[0028] Cr-Ti-V out-of-plane ordered MAX phase ceramic material Cr2(Ti) was prepared. 0.8 V 0.2 )AlC2.

[0029] Example 3 A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, with the chemical formula Cr2(Ti 0.7 V 0.3 AlC2. The preparation steps are as follows: Step 1: Using commercially available Cr powder, Ti powder, V powder, Al powder and C powder as raw materials, the ingredients are quantified according to the molar ratio of Cr powder, Ti powder, V powder, Al powder and C powder as 2:0.7:0.3:1.3:1.9.

[0030] Steps 2 and 3 are the same as in Example 1.

[0031] Cr-Ti-V out-of-plane ordered MAX phase ceramic material Cr2(Ti) was prepared. 0.7 V 0.3 )AlC2.

[0032] Example 4 A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, with the chemical formula Cr2(Ti 0.6 V 0.4 AlC2. The preparation steps are as follows: Step 1: Using commercially available Cr powder, Ti powder, V powder, Al powder and C powder as raw materials, the ingredients are quantified according to the molar ratio of Cr powder, Ti powder, V powder, Al powder and C powder as 2:0.6:0.4:1.4:1.9.

[0033] Steps 2 and 3 are the same as in Example 1.

[0034] Cr-Ti-V out-of-plane ordered MAX phase ceramic material Cr2(Ti) was prepared. 0.6 V 0.4 )AlC2.

[0035] Example 5 A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, with the chemical formula Cr2(Ti 0.5 V 0.5 AlC2, the preparation steps are as follows: Step 1: Using commercially available Cr powder, Ti powder, V powder, Al powder and C powder as raw materials, the ingredients are quantified according to the molar ratio of Cr powder, Ti powder, V powder, Al powder and C powder as 2:0.5:0.5:1.4:1.9.

[0036] Steps 2 and 3 are the same as in Example 1.

[0037] Cr-Ti-V out-of-plane ordered MAX phase ceramic material Cr2(Ti) was prepared. 0.5 V 0.5 )AlC2.

[0038] Comparative Example 1 A Cr-Ti based MAX phase ceramic material, with the chemical formula Cr2TiAlC2, is prepared as follows: Step 1: Using commercially available Cr powder, Ti powder, Al powder and C powder as raw materials, the ingredients are quantified according to the molar ratio of Cr powder, Ti powder, Al powder and C powder of 2:1:1.2:1.9.

[0039] Steps 2 and 3 are the same as in Example 1.

[0040] Cr-Ti based MAX phase ceramic material Cr2TiAlC2 was prepared.

[0041] Comparative Example 2 A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, with the chemical formula Cr2(Ti 0.4 V 0.6 AlC2, the preparation steps are as follows: Step 1: Using commercially available Cr powder, Ti powder, V powder, Al powder and C powder as raw materials, the ingredients are quantified according to the molar ratio of Cr powder, Ti powder, V powder, Al powder and C powder as 2:0.4:0.6:1.4:1.9.

[0042] Steps 2 and 3 are the same as in Example 1.

[0043] Cr-Ti-V based MAX phase ceramic material Cr2(Ti) was prepared. 0.4 V 0.6 )AlC2.

[0044] The properties of the MAX phase ceramic materials prepared in Examples 1-5 and Comparative Examples 1 and 2 were characterized as follows.

[0045] (1) Figure 1 The X-ray diffraction patterns of the MAX phase ceramic materials obtained in Examples 1-5 and Comparative Examples 1 and 2 are shown. It can be seen that the diffraction peak shapes of the Cr-Ti-V out-of-plane ordered MAX phase ceramic materials obtained in Examples 1-5 and Comparative Example 1 are consistent with the diffraction peak shapes of the Cr2TiAlC2 standard card, and none have obvious impurity peaks. This indicates that the Cr-Ti-V out-of-plane ordered MAX phase ceramic materials obtained in Examples 1-5 and the MAX phase ceramic materials obtained in Comparative Example 1 both have good crystallinity and phase purity. Meanwhile, the main phase purity of the Cr-Ti-V based MAX phase ceramic material obtained in Comparative Example 2 is significantly reduced, and obvious Cr2AlC impurity phases appear. This indicates that when the amount of V introduced is too large (… x When the ratio is 0.6), the Cr-Ti-V out-of-plane ordered MAX phase ceramic material of the present invention cannot be prepared. Therefore, the ceramic material Cr2(Ti) of the present invention cannot be prepared. 1-x V x In AlC2, 0 < x ≤0.5, the solid solution limit of V is x =0.5.

[0046] (2) Figure 2 The crystal axis parameters of the MAX phase ceramic materials obtained in Examples 1-5 and the ceramic material of Comparative Example 1 are as follows. a shaft and c The crystal axis parameters change with V content. It can be seen that, compared to Comparative Example 1, by introducing V solid solution, the crystal axis parameters of the MAX phase ceramic materials obtained in Examples 1-5... a shaft and c The average axis gradually decreases with increasing V content, indicating that V was successfully introduced into the lattice and formed a solid solution phase structure.

[0047] (3) The Cr-Ti-V out-of-plane ordered MAX phase ceramic materials obtained in Examples 1-5 and the MAX phase ceramic materials obtained in Comparative Example 1 were polished from 80 grit to about 3000 grit with sandpaper, and their surfaces were polished with 1.5 μm and 1 μm diamond polishing paste respectively. The different phases contained in the materials were observed using a high vacuum backscattered electron (CBS) probe of a scanning electron microscope (SEM), and the elemental distribution of the different phases of the samples was analyzed using a matching energy dispersive spectroscopy (EDS).

[0048] Scanning electron microscope backscattering image and EDS elemental distribution map are shown below Figure 3 Among them, (a) is the scanning electron microscope backscattering image and EDS elemental distribution map of the MAX phase ceramic material of Comparative Example 1; (b) to (f) are the scanning electron microscope backscattering images and EDS elemental distribution maps of the Cr-Ti-V out-of-plane ordered MAX phase ceramic materials obtained in Examples 1-5.

[0049] The elemental proportions analyzed by EDS energy dispersive spectroscopy are shown in Table 1. By observing the relative content of elements, it was found that the proportions of Cr, Ti, V, Al, and C in the prepared ceramic material samples are consistent with their stoichiometric ratios in their chemical formulas. Combined with... Figure 3 As shown in Table 1, the MAX phase ceramic material samples prepared by this invention have uniform composition.

[0050] Table 1. Atomic percentage of MAX phase ceramic materials obtained in Examples 1-5 and Comparative Example 1

[0051] Note: "-" indicates no data.

[0052] (4) Elemental characterization and analysis were performed using high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) combined with energy-dispersive X-ray spectroscopy (EDS). The results are as follows: Figure 4 As shown, the HAADF-STEM images reveal the typical layer stacking structure of MAX <11-20>, while the EDS images detect successful dissolution of V atoms. Along Figure 4 (a) The results of EDS line scanning along the C-axis are as follows Figure 4 As shown in (b), the periodic signal fluctuations of each element along the scanning path clearly indicate an ordered atomic distribution, and when V atoms dissolve, they form a solid solution with Ti atoms at site 2a. This proves that the obtained Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material still maintains its original sublattice out-of-plane ordered layered structure, while also exhibiting metal element solid solution, successfully achieving element solid solution of out-of-plane ordered MAX ceramic material.

[0053] (5) The Cr-Ti-V out-of-plane ordered MAX phase ceramic materials obtained by hot pressing sintering in Examples 1-5 and the material obtained in Comparative Example 1 were processed into semi-circular samples with a diameter of 25 mm by wire cutting. The samples were polished with sandpaper to about 3000 grit and polished with 1-micron diamond polishing paste. Friction tests were conducted on an HT-1000 ball-and-disc high-temperature friction and wear testing machine, which can be heated to 1000℃. ZrO2 balls with a diameter of 6 mm were used as the friction pair. All tests were conducted at room temperature and in air at 800℃ for 30 minutes with a load of 5 N, a rotation radius of 2 mm, and a rotation speed of 100 rpm. The friction coefficient was automatically recorded by a computer program, and each test data point was repeated at least three times. The final wear volume, three-dimensional pit image, and wear cross-sectional curve of the sample were measured using a three-dimensional profilometer. The wear rate was calculated by dividing the wear volume by the sliding distance and the applied load.

[0054] Figure 5 The images show scanning electron microscope (SEM) images of the MAX phase ceramic materials obtained in Examples 1-5 after friction tests at room temperature and 800°C. (a) is an SEM image of the MAX phase ceramic materials obtained in Examples 1-5 after friction tests at room temperature. (b) is an SEM image of the MAX phase ceramic materials obtained in Examples 1-5 after friction tests at 800°C. It can be seen that at room temperature, the width of the crater gradually decreases with increasing V content, corresponding to a decrease in wear rate. At 800°C, a dense and uniform friction film is formed on the surface of the prepared Cr-Ti-V out-of-plane ordered MAX phase ceramic materials, which is closely related to the stability of the friction coefficient and the improvement of wear resistance at high temperatures.

[0055] Figure 6 (a) is a friction coefficient-time graph of the MAX phase ceramic materials of Examples 1-5. (b) is a friction coefficient-time graph of the MAX phase ceramic materials of Examples 1-5 at 800°C. Figure 6 (c) shows the average friction coefficient of the MAX phase ceramic materials of Examples 1-5, Comparative Examples 1 and 2 at room temperature and 800°C. Figure 6(d) shows the average wear rate of the MAX phase ceramic materials of Examples 1-5 and Comparative Examples 1 and 2 at room temperature and 800°C. As can be seen from Figures (a) and (b), the friction coefficient of the MAX phase ceramic materials prepared in Examples 1-5 is significantly improved at 800°C compared to room temperature, and the long-term stability of the friction coefficient is also better than at room temperature. Figure (c) also shows that the average friction coefficient of Examples 1-5 is higher than that of Comparative Examples 1 and 2 at both room temperature and 800°C. At room temperature and 800°C, there is no significant difference in the average friction coefficient of the material in Comparative Example 1, while the average friction coefficient of the material in Comparative Example 2 decreases at high temperatures, falling below room temperature. The materials in Examples 1-5 show an increased average friction coefficient at 800°C, significantly higher than at room temperature. Figure (d) shows that the material in Example 5 has the lowest wear rate at room temperature, significantly lower than that in Comparative Examples 1 and 2, exhibiting both high friction coefficient and low wear rate. Although the wear rate of Examples 1-4 is higher than that in Comparative Examples 1 and 2, the friction coefficient of Examples 1-4 is significantly higher than that in Comparative Examples 1 and 2. When evaluating the frictional properties of materials, both the coefficient of friction and the wear rate need to be considered. At 800℃, Comparative Example 1 showed the lowest wear rate, but it was still roughly on the same order of magnitude as the wear rates of Examples 1-5, with little difference. Furthermore, the coefficient of friction for Examples 1-5 was significantly higher than that for Comparative Examples 1 and 2. Considering both the coefficient of friction and the wear rate, the material properties of Examples 1-5 are superior to those of Comparative Examples 1 and 2 under high-temperature conditions. This demonstrates that the Cr-Ti-V out-of-plane ordered MAX phase ceramic material prepared in this invention possesses excellent frictional stability and wear resistance.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A Cr-Ti-V basal out-of-plane ordered MAX phase ceramic material, characterized in that, The chemical formula of the ceramic material is: Cr2(Ti 1-x V x )AlC2; where 0 < x ≤ 0.5; the transition metal elements in the ceramic material have the characteristics of off-plane order of the sublattice.

2. The Cr-Ti-V out-of-plane ordered MAX phase ceramic material as described in claim 1, characterized in that, Using Cr, Ti, V, Al, and C powders as raw materials, the mixtures were ball-milled and then hot-pressed under an inert atmosphere. The hot-pressing conditions were: pressure 5 MPa to 20 MPa, temperature 1300℃ to 1500℃, and time 60 min to 180 min, to obtain Cr-Ti-V out-of-plane ordered MAX phase ceramic materials.

3. The Cr-Ti-V out-of-plane ordered MAX phase ceramic material as described in claim 2, characterized in that, The purity of the raw materials Cr, Ti, V, Al and C powders is ≥99%.

4. The Cr-Ti-V out-of-plane ordered MAX phase ceramic material as described in claim 2, characterized in that, The ball milling process is performed using intermittent ball milling.

5. The Cr-Ti-V out-of-plane ordered MAX phase ceramic material as described in claim 1, characterized in that, The inert gas is argon.

6. The application of a Cr-Ti-V out-of-plane ordered MAX phase ceramic material as described in any one of claims 1-5 in the preparation of braking materials.

7. The application of the Cr-Ti-V out-of-plane ordered MAX phase ceramic material as described in claim 6 in the preparation of braking materials, characterized in that, The braking material is used in an atmospheric environment ranging from room temperature to 800°C.

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