INTERLAYER ASYMMETRICALLY ALIGNED MULTI-ELEMENT MAX PHASE AND MXene, AND METHODS FOR PRODUCING THE SAME

Abstract

To provide an interlayer asymmetrically aligned multi-element MAX phase and MXene.SOLUTION: The disclosed MAX phase has a layered structure of M(n+1)AXn comprising a plurality of transition metal layers (where n is a natural number, and n and n+1 indicate the number of layers), wherein M comprises two or more transition metal elements, X comprises nitrogen or carbon, A comprises at least a first element and a second element that are different from each other and selected from Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements, a difference in atomic radius between the first element and the second element is 0.1 Å or more, and among the transition metal layers, a first transition metal layer and a second transition metal layer corresponding to outermost layers opposed to each other have compositions different from each other, whereby the MAX phase and MXene have an interlayer asymmetrically aligned structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to MXene. More particularly, the present invention relates to a multi-element MAX phase and MXene with asymmetric interlayer ordering, and methods for producing the same. [Background technology]

[0002] MXene is the corresponding three-dimensional Max phase (M( n+1 )AX n ) derived from the general formula M( n+1 )X n where M is an early transition metal (Ti, V, Cr, Nb, Ta, Zr, and Mo), A includes group 13 and 14 elements, and X is carbon or nitrogen.

[0003] Maxine is obtained by etching the Max phase and removing the MA bonds. Maxine has a high surface area, electrical conductivity, and unique optical properties, making it a new material with potential applications in a variety of areas, including batteries, photocatalysts, sensors, environmental purification, and electromagnetic wave shielding. To control these properties, a method can be used to manufacture Maxine by mixing various transition metals, and a stable solid solution Max phase, which is a transcription product of these metals, has been discovered.

[0004] To date, Max phases with various chemical orderings have been discovered, including a complete solid-solution Max phase in which the transition metals are uniformly mixed, an out-of-plane ordered Max phase in which the metal compositions of the central transition metal layer and the outer transition metal layer are differently ordered, and an in-plane ordered Max phase in which each transition metal layer has a unique ordering.

[0005] Among these, interlayer-ordered maxine (e.g., Mo2TiC2) exhibits semiconductor properties, unlike conventional maxine (Ti3C2), and can have a negative temperature coefficient of resistance. By adjusting the elements in the central atomic layer and the outer atomic layers, it can be converted into a diamagnetic or paramagnetic material.

[0006] In the case of a conventional interlayer aligned max phase or maxine, the two transition metal layers (M'') on the outer surface are symmetrically aligned from the central transition metal layer (M') in the form of M''2M'AX2 or M''2M'2AX3. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] China Patent Publication No. 116119668 [Non-patent literature]

[0008] [Non-Patent Document 1] Chemically complex double solid solution MAX phase-based ceramics in the (Ti,Zr,Hf,V,Nb)-(Al,Sn)-C system, Materials Research Letters, Vol 10, 2, 2022, 52-61 [Non-patent document 2] Non-Patent Document 2: Ta-based 413 and 211 MAX phase solid solutions with Hf and Nb, Journal of the European Ceramic Society, 40, 2020, 1829-1838 (2019-12-27) Summary of the Invention [Problem to be solved by the invention]

[0009] It is an object of the present invention to provide multi-element max phases and maxines with interlayer asymmetric ordering.

[0010] Another object of the present invention is to provide a method for preparing said Max phase and Maxine.

[0011] However, the object of the present invention is not limited to the above-mentioned object, and can be expanded in various ways without departing from the spirit and scope of the present invention. [Means for solving the problem]

[0012] To achieve the above object, the present invention provides a MAX phase comprising multiple transition metal layers (M( n+1 )AX n (n is a natural number, and n and n+1 represent the number of layers), M includes two or more transition metal elements, X includes nitrogen or carbon, A includes at least a first element and a second element selected from the group 13 elements, the group 14 elements, the group 15 elements, and the group 16 elements, and the difference in atomic radius between the first element and the second element is 0.1 Å or more, and the first transition metal layer and the second transition metal layer corresponding to the outermost layer opposite each other among the transition metal layers have different compositions, thereby forming an interlayer asymmetrical ordered structure.

[0013] The first element of A is Al, and the second element is Sn.

[0014] The molar ratio of Al to Sn is 1.8:1 to 2.2:1.

[0015] The Max phase has 312 phases.

[0016] M includes three or more elements, and the element that is most abundant in the first transition metal layer is the element with the highest atomic number among the elements in M, and the element that is most abundant in the second transition metal layer is the element with the lowest atomic number among the elements in M.

[0017] The transition metal layer further includes a third transition metal layer disposed between the first transition metal layer and the second transition metal layer, and M includes Ti, Zr, Hf, and Ta, the element most abundant in the first transition metal layer is Ti, the element most abundant in the second transition metal layer is Ta, and the element most abundant in the third transition metal layer is Hf.

[0018] The transition metal layer further includes a third transition metal layer disposed between the first transition metal layer and the second transition metal layer, and M includes Ti, Zr, Hf, and Ta, with Ti and Ta having the lowest content in the third transition metal layer and Zr and Hf having the lowest content in the second transition metal layer.

[0019] The maxine of the present invention is a M( n+1 )X n (n is a natural number, and n and n+1 represent the number of layers), M includes two or more transition metal elements, X includes nitrogen or carbon, and the first transition metal layer and the second transition metal layer corresponding to the outermost layers opposite each other have different compositions, thereby having an asymmetric interlayer ordering structure.

[0020] The method for producing the max phase according to the present invention includes the steps of mixing and milling raw materials of an M component containing two or more transition metal elements, an X component containing nitrogen or carbon, and an A component containing at least a first element and a second element different from each other selected from the group 13 elements, the group 14 elements, the group 15 elements, and the group 16 elements, and pressure-sintering the powder obtained by the milling to produce an M( n+1 )AX nand forming a MAX phase having a layered structure (n is a natural number, and n and n+1 represent the number of layers), wherein the difference in atomic radius between the first element and the second element is 0.1 Å or more, and the MAX phase has an asymmetric interlayer ordered structure, since the first transition metal layer and the second transition metal layer corresponding to the outermost layers opposite each other among the transition metal layers have different compositions, and the number of moles of the raw material of the A component is equal to or greater than the number of moles of the raw material of the M component.

[0021] The method for producing Max according to the present invention is characterized by comprising the step of removing A from the Max phase to obtain Maxine. [Effects of the Invention]

[0022] According to the present invention, it is possible to obtain a Max phase and Maxine with an asymmetrically ordered structure between layers, and by fine-tuning each transition metal layer, it is possible to adjust the composition of Maxine to have the properties desired for the application field.

[0023] Furthermore, Maxine with this structure has semiconductor properties as well as excellent photocatalytic, thermoelectric, and piezoelectric properties, making it suitable for use in a variety of fields, including sensors using the piezoelectric effect, biotechnology, computers, and home appliances using thermoelectric elements, and eco-friendly or hydrogen power generation using catalytic properties.

[0024] In addition, the Max phase and Maxine, whose outer layers are asymmetrically aligned, can adjust the semiconductor and magnetic properties, making them applicable to next-generation memory and advanced semiconductor fields. In particular, by adjusting the composition and structure, topological insulator properties are expected, making them useful in the field of quantum computers. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram showing the layered structure of the Max phase and Maxine according to one embodiment of the present invention. [Figure 2]FIG. 2 is a sequence diagram for explaining a method for manufacturing a max phase according to one embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the results of XRD (X-ray Diffraction) analysis of the Max phase of Example 1. [Figure 4] FIG. 4 is an enlarged image of a HAADF-TEM (High Angle Annular Dark Field-Transmission Electromicroscopy) photograph of the Max phase of Example 1. [Figure 5] FIG. 5 is a schematic diagram showing the atomic pair distribution function (PDF) of the Max phase in Example 1 and the results of large-box modeling obtained based on the measured values ​​of XRD. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, a multi-element asymmetrically ordered multi-element max phase and meccin according to an embodiment of the present invention, and a method for manufacturing the same, will be described in detail with reference to the accompanying drawings. The present invention may be modified in various ways and may have various forms, and specific embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the present invention to the specific disclosed form, but it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. In the accompanying drawings, the dimensions of structures are exaggerated to ensure clarity of the present invention.

[0027] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise" or "have" and the like are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the presence or possible addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an idealized or overly formal meaning unless expressly defined in this application.

[0029] FIG. 1 is a schematic diagram showing the layered structure of the Max phase and Maxine according to one embodiment of the present invention.

[0030] The Max phase according to one embodiment of the present invention is M( n+1 )AX n (n is a natural number, and n and n+1 indicate the number of layers). M is a transition metal (early transition metal) and contains two or more elements. For example, M contains two or more elements selected from Ti, V, Cr, Zr, Nb, Mo, Hf, and Ta. A contains two or more elements selected from Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements. For example, A contains two or more elements selected from Al, Si, P, S, Ga, Ge, As, In, and Sn. The two elements contained in A have different atomic radii. For example, the difference in atomic radii of the two elements contained in A is 0.1 Å or more.

[0031] For example, A includes a first element and a second element having an atomic radius larger than that of the first element. According to one embodiment, A includes Al and Sn. X represents N or C.

[0032] Thus, the Max phase and Maxine contain at least two layers containing M. As shown in FIG. 1, the Max phase and Maxine have three layers containing M (transition metals) and two layers containing X. For example, the Max phase contains a first M layer (LM1), a second M layer (LM2), and a third M layer (LM3). The first M layer (LM1) and the second M layer (LM2) correspond to outer layers adjacent to the A layer (LA), respectively, and the third M layer (LM3) corresponds to an intermediate layer disposed between the first M layer (LM1) and the second M layer (LM2). Two X layers are disposed between the first M layer (LM1) and the third M layer (LM3), and between the second M layer (LM2) and the third M layer (LM3), respectively. Maxine is obtained by removing the A layer from the Max phase.

[0033] According to one embodiment, the multiple M layers of the Max phase and Maxine have different compositions. For example, the first M layer (LM1) and the second M layer (LM2) in contact with the A layer (LA) have different compositions, thereby forming an asymmetrically ordered structure between layers. As shown in FIG. 1, the first M layer (LM1) contains a first M element (M 1 ), and the second M layer (LM2) is composed of a second M element (M 2 ), each M layer may not actually be made of a single element, but may contain multiple elements and have different compositions.

[0034] For example, the first M layer (LM1) contains a first M element (M 1 ) at the highest content, and the second M layer (LM2) contains the first M element (M 1 ) and a second M element (M 2 The third M layer (LM3), which corresponds to the intermediate layer, contains the third M element (M 3) in the highest content, but the present invention is not limited thereto, and the third M layer (LM3) contains the first M element (M 1 ) or a second M element (M 2 ) may also be included in the highest content.

[0035] According to one embodiment, the first M element (M 1 ) is the element with the lowest atomic number among the elements contained in M, and is the second M element (M 2 ) is the element with the highest atomic number among the elements in M.

[0036] As described above, the number of layers of M may be two or more and may contain two or more elements. Therefore, the present invention is not limited to the above structure. When the M layers in contact with the A layer have different compositions, it can be defined as having an asymmetrically ordered structure between layers.

[0037] For example, M includes four or more different elements, and the number of layers of M is 3. Alternatively, M includes two to four different elements, and the number of layers of M is 5 or more. Alternatively, M includes two or more different elements, and the number of layers of M is 2.

[0038] According to one embodiment, in the Max phase and Maxine, the number of M layers is three, M includes Ti, Zr, Hf, and Ta, and A includes Al and Sn. The A layer has a solid-solution phase of Al and Sn mixed together. If the Max phase includes a first M layer and a second M layer corresponding to the outer layer adjacent to the A layer (LA), and a third M layer corresponding to the intermediate layer, the element with the highest content in the first M layer is Ti, the element with the highest content in the second M layer is Ta, and the element with the highest content in the third M layer is Hf. Furthermore, Ti and Ta have the lowest contents in the third M layer, and Zr and Hf have the lowest contents in the second M layer. Furthermore, Zr has the highest content in the third M layer.

[0039] FIG. 2 is a sequence diagram illustrating a method for manufacturing a Max phase according to one embodiment of the present invention. As shown in FIG. 2, ball milling is used to obtain the Max phase according to one embodiment of the present invention, as with general Max phases. For example, powders of each elemental component are mixed and ball milled, and the resulting powder is pelletized and sintered in an inert gas atmosphere. The Max phase can then be obtained by removing intermetallic compounds and carbide impurities from the sintered body using a strong acid such as hydrochloric acid. Alternatively, Maxine can be obtained by heating the Max phase at high temperatures in molten salt or by treating it with hydrofluoric acid to remove the A layer.

[0040] According to one embodiment, when mixing the elemental components, the contents of the M and C components are the same or similar to the composition of the desired Max phase, but the A component is added in excess. The Max phase and A layer generally tend to form a symmetric structure at temperatures above the high temperature at which the Max phase forms (approximately 1,400°C). However, the A layer formed by melting the excess A component at high temperature acts as a solvent, substantially lowering the temperature at which the Max phase or A layer is formed, thereby forming an asymmetric structure.

[0041] According to one embodiment, when the number of transition metal layers is three and the A layer is to obtain a M3AC2 Mack phase containing Al and Sn, the molar ratio of M to Al is 3:2.5 to 3:2.7. If the Al content is too low, the M2AC impurity content increases, which substantially increases the Mack phase formation temperature and results in a symmetric Mack phase. If the content of M containing Al is too high, the amount of intermetallic compounds increases.

[0042] The molar ratio of Al to Sn is 1:0.15 to 1:0.25, for example, about 1:0.2. The ratio of M to the total A component including Al and Sn is 3:3 to 3:3.2. That is, the number of moles of A component is equal to or greater than the number of moles of M component. This is much higher than the quantitative range of Max phase and Maxine and the A content used in the production of existing Max phase.

[0043] The molar ratio of Al to Sn in the Max phase and the Maxine A layer is about 2: 1. Taking into account the margin of error, the molar ratio of Al to Sn is 1.8:1 to 2.2:1.

[0044] The A layer, which has a solid solution of the above composition, has distortion, which may result in differences in affinity, electronegativity, etc. As a result, the resulting Max phase forms a stable structure, and the M layer (transition metal layer) adjacent to the top surface of the A layer and the M layer adjacent to the bottom surface may have different compositions. As a result, the M layer adjacent to the A layer may have an asymmetric interlayer alignment.

[0045] According to one embodiment, the resulting Max phase and Maxine have a 312 phase.

[0046] According to the present invention, it is possible to obtain a Max phase and Maxine with an asymmetrically ordered structure between layers, and by fine-tuning each transition metal layer, it is possible to adjust the composition of Maxine to have the properties desired for the application field.

[0047] Furthermore, Maxin with this structure has semiconductor properties as well as excellent photocatalytic, thermoelectric, and piezoelectric properties, making it suitable for use in a variety of fields, including sensors using the piezoelectric effect, biotechnology, computers, and home appliances using thermoelectric elements, and eco-friendly or hydrogen power generation using catalytic properties.

[0048] In addition, the Max phase and Maxine, whose outer layers are asymmetrically aligned, can adjust the semiconductor and magnetic properties, making them applicable to next-generation memory and advanced semiconductor fields. In particular, by adjusting the composition and structure, topological insulator properties are expected, making them useful in the field of quantum computers.

[0049] The manufacture and effects of the present invention will be described below through specific examples and experimental examples. The examples and experimental examples are provided for illustrative purposes only, and the scope of the present invention is not limited to the contents provided in the experimental examples. [Example]

[0050] Example 1 Powders of Ti, Zr, Hf, Ta, Al, Sn, and C were mixed in a ratio of 0.75:0.75:0.75:0.75:2.6:0.52:1.8, and milled for a total of 10 hours using 100 g of zirconia balls with a diameter of 5 mm (ball to powder ratio 5:1), milling for 10 minutes followed by cooling for 5 minutes.

[0051] 3 g of the powder obtained by milling was placed in an 8 mm steel mold and a pressure of 100 MPa was applied to produce green pellets. The green pellets were placed in alumina glass and sintered under atmospheric pressure at 1,500°C in an argon atmosphere for 4 hours (heating rate: 3°C / min).

[0052] The sintered pellets were crushed and sieved, and then reacted with HCl for more than 18 hours to remove intermetallic impurities (such as ZrAl3) and obtain the max phase.

[0053] The analysis of the obtained MAX phase by EDS (Energy-Dispersive X-ray Spectroscopy) revealed that the composition of the MAX phase was (Ti 0.818 Zr 0.545 Hf 0.818 Ta 0.818 )3(Al 0.66 Sn 0.33 )C2(=(Ti 3 / 11 Zr 2 / 11 Hf 3 / 11 Ta 3 / 11 )3(Al 2 / 3 Sn 1 / 3 )C2).

[0054] The Max phase was placed in a molten salt consisting of CuCl2-KCl-NaCl and heated at 750°C, and the A layer (Al, Sn) was etched to obtain Maxine.

[0055] 3 shows the XRD (X-ray diffraction) analysis results of the Max phase of Example 1. Obs is the measured value, and Calc is the calculated value of the interlayer symmetric structure Max phase predicted through the composition.

[0056] As shown in Figure 3, contrary to the expected result, the (004) peak was not present, but the (006) peak was observed, confirming that the max phase of Example 1 does not have an interlayer symmetric structure.

[0057] FIG. 4 is an enlarged image of a HAADF-TEM (High Angle Annular Dark Field-Transmission Electron Microscopy) photograph of the Max phase of Example 1.

[0058] As shown in Figure 4, the Max phase of Example 1 contains three transition metal layers, and it was confirmed that the distances from the intermediate layer to the A layers on both sides are different, which indicates that the Max phase of Example 1 has an asymmetric interlayer ordering structure.

[0059] To track the composition of the Max phase in Example 1, large-box modeling was performed to refine the structure by fitting the atomic pair distribution function (PDF) and XRD measurements through reverse Monte Carlo simulation. Figure 5 is a schematic diagram showing the results of large-box modeling obtained based on the atomic pair distribution function (PDF) and XRD measurements of the Max phase in Example 1.

[0060] The structure determined by large-box modeling in FIG. 5 was analyzed, and the element ratios of each transition metal layer were shown in Table 1 below.

[0061] [Table 1]

[0062] From Table 1, it can be seen that the Max phase of Example 1 is the first M layer (M 1 ) and the second M layer (M 2 ), and a third M layer (M 3 ), the element with the highest content in the first M layer is Ti, the element with the highest content in the second M layer is Ta, and the element with the highest content in the third M layer is Hf. It was also confirmed that the contents of Ti and Ta are lowest in the third M layer, the contents of Zr and Hf are lowest in the second M layer, and the content of Zr is highest in the third M layer.

[0063] While the present invention has been described with reference to exemplary embodiments thereof, those skilled in the art will appreciate that various modifications and variations can be made thereto without departing from the spirit and scope of the present invention as set forth in the following claims. [Industrial Applicability]

[0064] Embodiments of the present invention can be used in a variety of fields, such as the sensor field using the piezoelectric effect, biotechnology using thermoelectric elements, computers, home appliances, eco-power generation or hydrogen power generation using catalytic properties, and the semiconductor field using semiconductor properties.

Claims

1. M( ｎ＋１ ) AX ｎ (n is a natural number, and n and n+1 represent the number of layers), M contains two or more transition metal elements; X contains nitrogen or carbon; A includes at least a first element and a second element which are different from each other and selected from the group consisting of Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements; a difference between the atomic radii of the first element and the second element is 0.1 Å or more; Among the transition metal layers, the first transition metal layer and the second transition metal layer corresponding to the outer layers opposite each other have different compositions, thereby having an asymmetric interlayer ordering structure. MAX phase.

2. 2. The Max phase of claim 1, wherein the first element of A is Al and the second element of A is Sn.

3. The Max phase according to claim 2, characterized in that the molar ratio of Al to Sn is 1.8:1 to 2.2:

1.

4. The max phase of claim 1 , wherein the max phase comprises a 312 phase.

5. M contains three or more elements, the element with the highest content in the first transition metal layer is the element with the highest atomic number among the elements of M, The max phase according to claim 1 , wherein the element with the highest content in the second transition metal layer is the element with the lowest atomic number among the elements of M.

6. the transition metal layer further includes a third transition metal layer disposed between the first transition metal layer and the second transition metal layer; M includes Ti, Zr, Hf, and Ta; the element with the highest content in the first transition metal layer is Ti; the element with the highest content in the second transition metal layer is Ta; The max phase according to claim 1 , wherein the element with the highest content in the third transition metal layer is Hf.

7. the transition metal layer further includes a third transition metal layer disposed between the first transition metal layer and the second transition metal layer; M includes Ti, Zr, Hf, and Ta; Ti and Ta have the lowest contents in the third transition metal layer, The max phase according to claim 1 , wherein the Zr and Hf contents are lowest in the second transition metal layer.

8. M( ｎ＋１ ) X ｎ (n is a natural number, and n and n+1 represent the number of layers), M contains two or more transition metal elements; X contains nitrogen or carbon; Among the transition metal layers, the first transition metal layer and the second transition metal layer corresponding to the outermost layers opposite each other have different compositions, thereby forming an asymmetric interlayer alignment structure.

9. 9. The maxine of claim 8, wherein the maxine has 312 phases.

10. M contains three or more elements, the element with the highest content in the first transition metal layer is the element with the highest atomic number among the elements of M, 9. The maxin according to claim 8, wherein the element with the highest content in the second transition metal layer is the element with the lowest atomic number among the elements of M.

11. the transition metal layer further includes a third transition metal layer disposed between the first transition metal layer and the second transition metal layer; M includes Ti, Zr, Hf, and Ta; the element with the highest content in the first transition metal layer is Ti; the element with the highest content in the second transition metal layer is Ta; 9. The maxin according to claim 8, wherein the element with the highest content in the third transition metal layer is Hf.

12. the transition metal layer further includes a third transition metal layer disposed between the first transition metal layer and the second transition metal layer; M includes Ti, Zr, Hf, and Ta; Ti and Ta have the lowest contents in the third transition metal layer; 9. The maxin of claim 8, wherein Zr and Hf are present in the second transition metal layer at the lowest concentrations.

13. a step of mixing and milling raw materials of an M component containing two or more transition metal elements, an X component containing nitrogen or carbon, and an A component containing at least a first element and a second element different from each other selected from Group 13 elements, Group 14 elements, Group 15 elements, and Group 16 elements; The powder obtained by the milling is pressure-sintered to form M( ｎ＋１ ) AX ｎ and forming a MAX phase having a layered structure of (n is a natural number, and n and n+1 represent the number of layers), a difference between the atomic radii of the first element and the second element is 0.1 Å or more; The max phase has an interlayer asymmetric ordering structure because the first transition metal layer and the second transition metal layer corresponding to the outermost layers opposite each other among the transition metal layers have different compositions. A method for producing a max phase, characterized in that the number of moles of the raw material of the A component is equal to or greater than the number of moles of the raw material of the M component.

14. The method for producing the max phase according to claim 13, wherein the first element of the A component is Al and the second element is Sn.

15. 15. The method for producing the max phase according to claim 14, wherein n is 2, and the raw material molar ratio of the M component to Al is 3:2.5 to 3:2.

7.

16. The method for producing the max phase according to claim 15, characterized in that the raw material molar ratio of Al to Sn is 1:0.15 to 1:0.25, and the molar ratio of Al to Sn within the max phase is 1.8:1 to 2.2:

1.

17. The method for producing the MAX phase according to claim 13, characterized in that the MAX phase has a 312 phase.

18. The method for producing a max phase according to claim 14, wherein the M component includes Ti, Zr, Hf, and Ta.

19. The method for producing the max phase according to claim 14, wherein the milling step uses zirconia balls.

20. 20. The method of any one of claims 13 to 19, comprising producing a MAX phase; and removing the component A from the max phase to obtain maxine.

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