Silicon-containing high-entropy MAB phase ceramic powder and preparation method thereof

Abstract

The invention relates to the technical field of ceramic materials, in particular to silicon-containing high-entropy MAB phase ceramic powder and a preparation method thereof. The chemical formula of the silicon-containing high-entropy MAB phase ceramic powder is M4CrSiB2, M is transition metal, and the transition metal is equal in stoichiometric ratio or nearly equal in stoichiometric ratio. According to the method, the elementary substance powder is used as a raw material, sintering is carried out in the Joule heating equipment in a rapid temperature rising and falling and short-time heat preservation mode, generation of a complex intermediate phase and loss of volatile raw materials in the sintering process are effectively avoided, and accurate and rapid preparation of the single-phase silicon-containing high-entropy MAB phase ceramic powder is achieved. The preparation method provided by the invention has the advantages of low cost, simple process, high synthesis efficiency, low energy consumption and the like, and is suitable for batch production.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, specifically to a silicon-containing high-entropy MAB phase ceramic powder and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] MAB phase ceramics are ternary layered ceramics, where M is a transition metal element, A is aluminum or silicon, and B is boron. This material combines the properties of both metals and ceramics, exhibiting excellent mechanical properties, high damage tolerance, oxidation resistance, and machinability, making it highly promising for applications in high-temperature oxidizing environments. Currently, research on MAB phase ceramics mainly focuses on aluminum-containing MAB phase ceramics such as MoAlB and Fe2AlB2, while reports on silicon-containing MAB phase ceramics are relatively limited.

[0004] High-entropy ceramics are near-equimolar multi-component single-phase solid solution ceramic materials. Their unique "high-entropy effect" gives them distinct advantages in mechanical, thermal, and oxidation resistance properties. However, there are currently no reports of silicon-containing high-entropy MAB phase ceramics, hindering the further expansion of MAB phase ceramic varieties. Introducing solid solution atoms at the M or A positions of MAB phase ceramics can effectively affect their properties. Therefore, simultaneously introducing multiple solid solution atoms at the M position to form silicon-containing high-entropy MAB phase ceramics holds promise for providing broader scope for composition and performance control. However, the preparation of silicon-containing high-entropy MAB phase ceramics still faces the following bottlenecks: (1) The crystal form and purity of silicon-containing MAB phase ceramics are closely related to the type and ratio of transition metal elements at the M site. Due to the influence of the selected components, some silicon-containing MAB phase ceramics failed to obtain high-purity target products. For example, the purity of Ta4VSiB2 ceramics was 81 wt%, while the purity of Ta4MoSiB2 ceramics was only 46 wt%. For silicon-containing high-entropy MAB phase ceramics, the increase in the number of element components increases the difficulty of selecting the type and ratio of transition metal elements. Only by rationally selecting the components can high-purity target products be prepared.

[0005] (2) The preparation of MAB phase ceramic powder is mainly achieved through high-temperature solid-state reaction, which generally involves slow heating and cooling and long-term holding. Moreover, the preparation of high-entropy ceramics often requires holding at higher temperatures for longer periods to ensure the full solid solution of various elements. The raw materials for synthesizing the MAB phase undergo complex intermediate states during slow heating, resulting in the presence of various borides or alloy byproducts in the product. For the preparation of silicon-containing high-entropy MAB phase ceramics, the diversity of raw material types makes the intermediate reaction more complex and makes it more difficult to obtain high-purity target products. In addition, long-term high-temperature reactions lead to the loss of volatile raw materials, making it difficult to accurately control the stoichiometry of each element in silicon-containing high-entropy MAB phase ceramic powder. Furthermore, conventional high-temperature solid-state reactions also have problems such as low preparation efficiency and high energy consumption, making it difficult to achieve efficient synthesis of silicon-containing high-entropy MAB phase ceramic powder with a huge component control range, which is not conducive to industrialization and limits the practical application of this material. Summary of the Invention

[0006] To overcome the above problems, the present invention provides a silicon-containing high-entropy MAB phase ceramic powder and its preparation method.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a silicon-containing high-entropy MAB phase ceramic powder with the chemical formula M4CrSiB2, wherein M is a transition metal selected from at least three of titanium, molybdenum, tungsten, niobium and tantalum, and the transition metals are in stoichiometric or near-stoichiometric ratios.

[0008] A second aspect of the present invention provides a method for preparing the silicon-containing high-entropy MAB phase ceramic powder described in the first aspect, comprising the following steps: (1) Weigh the transition metal powder, chromium powder, silicon powder and boron powder according to the chemical formula M4CrSiB2; (2) Various powders are wet-milled and vacuum-dried to obtain a mixed powder; (3) The mixed powder is hydraulically compacted to obtain a dense green body; (4) The blank is embedded in a graphite carrier for Joule thermal sintering, and after cooling, a bulk sample is obtained; (5) The bulk sample was crushed and ground to obtain silicon-containing high-entropy MAB phase ceramic powder.

[0009] In one or more embodiments, in step (2), the milling medium is anhydrous ethanol or methanol.

[0010] In one or more embodiments, in step (2), the ball milling speed is 200~400 rpm and the ball milling time is 12~24 h.

[0011] In one or more embodiments, in step (2), the drying temperature is 60~150 ℃ and the drying time is 8~24h.

[0012] In one or more embodiments, in step (3), the hydraulic pressure is 150~300 MPa and the pressure holding time is 5~15 min.

[0013] In one or more embodiments, in step (4), the selected graphite carrier is graphite paper, graphite felt, or graphite plate.

[0014] In one or more embodiments, in step (4), the reaction is carried out under a protective gas, which is argon or helium.

[0015] In one or more embodiments, in step (4), the heating rate is 10. 3 ~10 5 ℃ / min, sintering temperature is 1700~1900 ℃, holding time is 20~60 s; The cooling rate is 10 3 ~10 5 ℃ / min.

[0016] The beneficial effects of this invention are as follows: (1) This invention prepares silicon-containing high-entropy MAB phase ceramic powder by rapid heating and cooling and short-term heat preservation. During the rapid heating process, the agglomeration of atoms in the reactants is suppressed by kinetic control, realizing rapid and uniform diffusion of atoms and improving the growth rate of ceramic grains. Subsequently, the non-uniform reaction products are held at the target sintering temperature for a short time, and the non-uniform reaction products form a high-entropy phase with a single-phase lattice through atomic diffusion and particle fusion. Finally, the high-entropy phase is frozen and preserved by rapid cooling.

[0017] (2) The silicon-containing high-entropy MAB phase ceramic powder prepared by the present invention has a wide range of composition control space. The ceramic powder has good stability in high-temperature oxidation environment and has broad application prospects in the preparation of high-temperature thermal structural components.

[0018] (3) In the preparation method provided by the present invention, rapid heating helps to cross the reaction intermediate state, avoids the generation of complex intermediate phases during sintering, and is conducive to obtaining high-purity target products. Rapid heating and short-term holding can suppress the loss of volatile raw materials and can precisely control the stoichiometric ratio of each element in the ceramic powder. Rapid cooling can make the high-entropy phase reach the final stable state in a short time, effectively avoiding phase separation.

[0019] (4) The preparation method provided by the present invention has the advantages of low cost, simple process, high synthesis efficiency and low energy consumption, and is suitable for mass production of silicon-containing high-entropy MAB phase ceramic powder. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 The silicon-containing high-entropy MAB phase (Ta) in Example 1 1 / 3 Mo 1 / 3 W 1 / 3 Scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) plots of 4CrSiB2 ceramic powder; Figure 2 The silicon-containing high-entropy MAB phase (Ta) in Example 1 1 / 3 Mo 1 / 3 W 1 / 3 XRD pattern of 4CrSiB2 ceramic powder; Figure 3 The silicon-containing high-entropy MAB phase (Ta) in Example 1 1 / 3 Mo 1 / 3 W 1 / 3 TG-DSC curve of 4CrSiB2 ceramic powder in air. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0025] Example 1 (1) Weigh out tantalum powder, molybdenum powder, tungsten powder, chromium powder, silicon powder and boron powder according to the element molar ratio Ta:Mo:W:Cr:Si:B=4:4:4:3:3:6; (2) The weighed raw materials were placed in anhydrous ethanol and mixed evenly by wet mechanical ball milling (the ball milling speed was 300 r / min and the ball milling time was 20 h). The mixture after ball milling was vacuum dried at 80 ℃ for 20 h to obtain mixed powder. (3) Under a hydraulic pressure of 200 MPa, the mixture is pressed into a dense blank for 10 min. (4) Embed the blank into the graphite paper and place the graphite paper on the sample rack of the Joule heating device. Heat it to 1800 ℃ in an argon atmosphere at 180 ℃ / s, hold it for 30 s, and then cool it at 180 ℃ / s to obtain the block sample. (5) The bulk sample was crushed and ground to obtain a silicon-containing high-entropy MAB phase (Ta). 1 / 3 Mo 1 / 3 W 1 / 3 4CrSiB2 ceramic powder.

[0026] Figure 1 It is a silicon-containing high-entropy MAB phase (Ta 1 / 3 Mo 1 / 3 W 1 / 3 Scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) elemental distribution maps of 4CrSiB2 ceramic powder, from... Figure 1 As can be seen from this, the obtained silicon-containing high-entropy MAB phase (Ta) 1 / 3 Mo 1 / 3 W 1 / 3 The microstructure of 4CrSiB2 ceramic powder is a lamellar structure, and the constituent elements are evenly distributed with no obvious elemental segregation.

[0027] Figure 2 It is a silicon-containing high-entropy MAB phase (Ta 1 / 3 Mo 1 / 3 W 1 / 3 XRD patterns of 4CrSiB2 ceramic powder, from Figure 2 As can be seen from this, the obtained silicon-containing high-entropy MAB phase (Ta) 1 / 3 Mo 1 / 3 W 1 / 3 The 4CrSiB2 ceramic powder has good crystallinity and almost no impurity peaks.

[0028] Figure 3 It is a silicon-containing high-entropy MAB phase (Ta 1 / 3 Mo 1 / 3 W 1 / 3 The TG-DSC curve of 4CrSiB2 ceramic powder in air, from Figure 3 As can be seen, the ceramic powder begins to show oxidation weight gain and exothermic peaks at 700~850 ℃, and no obvious oxidation exothermic peaks appear as the temperature continues to rise, indicating that the ceramic powder has good stability in high-temperature oxidation environment.

[0029] Example 2 (1) Weigh out tantalum powder, molybdenum powder, tungsten powder, chromium powder, silicon powder and boron powder according to the element molar ratio Ta:Mo:W:Cr:Si:B=4:4:4:3:3:6; (2) The weighed raw materials were placed in anhydrous ethanol and mixed evenly by wet mechanical ball milling (the ball milling speed was 300 r / min and the ball milling time was 18 h). The mixture after ball milling was vacuum dried at 80 ℃ for 15 h to obtain mixed powder. (3) Under a hydraulic pressure of 200 MPa, the mixture is pressed into a dense blank for 15 min. (4) Embed the blank into the graphite felt and place the graphite felt on the sample rack of the Joule heating device. Heat it to 1900 ℃ at 125 ℃ / s in an argon atmosphere, hold it for 30 s, and then cool it at 125 ℃ / s to obtain the block sample. (5) The bulk sample was crushed and ground to obtain a silicon-containing high-entropy MAB phase (Ta). 1 / 3 Mo 1 / 3 W 1 / 3 4CrSiB2 ceramic powder.

[0030] Example 3 (1) Weigh out titanium powder, molybdenum powder, tungsten powder, chromium powder, silicon powder and boron powder according to the element molar ratio Ti:Mo:W:Cr:Si:B=4:4:4:3:3:6; (2) The weighed raw materials were placed in anhydrous ethanol and mixed evenly by wet mechanical ball milling (the ball milling speed was 250 r / min and the ball milling time was 24 h). The mixture after ball milling was vacuum dried at 80 ℃ for 20 h to obtain mixed powder. (3) Under a hydraulic pressure of 200 MPa, the mixture is pressed into a dense blank for 10 min. (4) Embed the blank into the graphite paper and place the graphite paper on the sample rack of the Joule heating device. Heat it to 1800 ℃ in an argon atmosphere at 180 ℃ / s, hold it for 40 s, and then cool it at 180 ℃ / s to obtain the block sample. (5) The bulk sample was crushed and ground to obtain a silicon-containing high-entropy MAB phase (Ti). 1 / 3 Mo 1 / 3 W 1 / 3 4CrSiB2 ceramic powder.

[0031] Example 4 (1) Weigh out titanium powder, tantalum powder, molybdenum powder, chromium powder, silicon powder and boron powder according to the element molar ratio Ti:Ta:Mo:Cr:Si:B=4:4:4:3:3:6; (2) The weighed raw materials were placed in anhydrous ethanol and mixed evenly by wet mechanical ball milling (the ball milling speed was 300 r / min and the ball milling time was 20 h). The mixture after ball milling was vacuum dried at 80 ℃ for 20 h to obtain mixed powder. (3) Under a hydraulic pressure of 200 MPa, the mixture is pressed into a dense blank for 10 min. (4) Embed the blank into the graphite paper and place the graphite paper on the sample rack of the Joule heating device. Heat it to 1800 ℃ in an argon atmosphere at 180 ℃ / s, hold it for 30 s, and then cool it at 180 ℃ / s to obtain the block sample. (5) The bulk sample was crushed and ground to obtain a silicon-containing high-entropy MAB phase (Ti). 1 / 3 Ta 1 / 3 Mo 1 / 3 4CrSiB2 ceramic powder.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A silicon-containing high-entropy MAB phase ceramic powder, characterized in that, Its chemical formula is M4CrSiB2, where M is a transition metal selected from at least three of titanium, molybdenum, tungsten, niobium and tantalum, with each transition metal having an equistoichiometric or near-equistoichiometric ratio.

2. The method for preparing silicon-containing high-entropy MAB phase ceramic powder according to claim 1, characterized in that, Includes the following steps: (1) Weigh the transition metal powder, chromium powder, silicon powder and boron powder according to the chemical formula M4CrSiB2; (2) Various powders are wet-milled and vacuum-dried to obtain a mixed powder; (3) The mixed powder is hydraulically compacted to obtain a dense green body; (4) The blank is embedded in a graphite carrier for Joule thermal sintering, and after cooling, a bulk sample is obtained; (5) The bulk sample was crushed and ground to obtain silicon-containing high-entropy MAB phase ceramic powder.

3. The preparation method according to claim 2, characterized in that, In step (2), the ball milling medium is anhydrous ethanol or methanol.

4. The preparation method according to claim 2, characterized in that, In step (2), the ball milling speed is 200~400 rpm and the ball milling time is 12~24 h.

5. The preparation method according to claim 2, characterized in that, In step (2), the drying temperature is 60~150 ℃ and the drying time is 8~24 h.

6. The preparation method according to claim 2, characterized in that, In step (3), the hydraulic pressure is 150~300 MPa and the pressure holding time is 5~15 min.

7. The preparation method according to claim 2, characterized in that, In step (4), the selected graphite carrier is graphite paper, graphite felt or graphite plate.

8. The preparation method according to claim 2, characterized in that, In step (4), the reaction is carried out under a protective gas, which is argon or helium.

9. The preparation method according to claim 2, characterized in that, In step (4), the heating rate is 10. 3 ~10 5 The sintering rate was ℃ / min, the sintering temperature was 1700~1900 ℃, and the holding time was 20~60 s.

10. The preparation method according to claim 2, characterized in that, In step (4), the cooling rate is 10. 3 ~10 5 ℃ / min.

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