Hafnium-tantalum-zirconium ternary carbide whisker as well as preparation method and application thereof

Abstract

The invention discloses a hafnium-tantalum-zirconium ternary carbide whisker and a preparation method and application thereof, and the preparation method of the whisker comprises the following steps: (1) mixing a metal oxide, a carbon source and a halide to obtain precursor powder; (2) carrying out temperature control reaction on the precursor powder in a heat treatment furnace to obtain hafnium-tantalum-zirconium ternary carbide whiskers; the metal oxides are hafnium oxide, tantalum oxide and zirconium oxide. Therefore, the preparation process is simple and convenient to operate, the product structure, components and morphology can be regulated and controlled, and the prepared hafnium-tantalum-zirconium ternary carbide whisker grows vertically, has excellent high-temperature stability, mechanical property, heat conduction performance, electrical conductivity and oxidation / ablation resistance and has wide application prospects in the fields of ceramic materials, microelectronic devices and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of whisker materials, and in particular relates to a hafnium tantalum zirconium ternary carbide whisker and a preparation method and application thereof. Background Art

[0002] Ultra-high temperature ceramics have a melting point of over 3000°C and maintain stable physical and chemical properties in extreme environments. They mainly include transition metal Me (Me = Hf, Ta, Zr, Ti, Nb) carbides, borides and nitrides. The extremely strong chemical bonds of this type of material determine its many excellent properties such as high melting point, high hardness, high strength and corrosion resistance, making it a material with great application potential in the ultra-high temperature field.

[0003] Compared to single carbides such as HfC, TaC, and ZrC, multi-component carbides possess superior overall properties, such as melting point, elastic modulus, strength, hardness, thermal conductivity, and electrical conductivity, making them promising carbide ultra-high-temperature ceramics. Currently, there are few reports on the preparation of multi-component carbide whiskers.

[0004] Literature 1( N,Johnsson M,Larsson AK,et al.On the carbothermalvapour-liquid-solid(VLS)mechanism for TaC,TiC,and Ta x Ti 1-x C whiskergrowth.Journal of the European Ceramic Society.2000,20:2607-2618)Ta2O5, TiO2, C, NaCl as raw materials, Ni as catalyst by carbothermal reduction method to prepare Ta x Ti 1-x C whiskers, the whisker yield obtained by this method is low and the whisker diameter distribution is uneven. In addition, the Ni catalyst introduces metal impurities and easily accumulates at the top of the whiskers, affecting their service stability in high-temperature oxygen environments.

[0005] CN11830810B discloses an ultra-high-porosity hafnium-tantalum-niobium ternary carbide ultra-high-temperature thermal insulation material. The material uses hafnium carbide, tantalum carbide, and niobium carbide powders as raw materials, and water as the dispersion medium to prepare a ceramic slurry. The slurry is then heated, a foaming agent is added, and rapidly stirred to foam. The slurry is then injection molded and frozen to form a green body. This is followed by vacuum drying, demolding, and oven drying. Finally, the porous hafnium-tantalum-niobium ternary carbide ceramic is sintered in a tubular furnace and a high-temperature carbon tube furnace, respectively. The resulting ternary carbide has a blocky structure and is suitable for use as a thermal insulation material in high-temperature thermal protection applications.

[0006] Currently, research on ternary carbide ceramics focuses on the preparation of ceramic blocks or coatings, while there are very few reports on the preparation method of ternary carbide whiskers. Therefore, there is an urgent need to develop a hafnium tantalum zirconium ternary carbide whisker and its preparation method, in order to enhance the mechanical properties, high-temperature stability, and oxidation / ablation resistance of composite materials and ultra-high temperature ceramics, and broaden the application prospects of whisker materials in the field of microelectronic devices, such as electromagnetic shielding and field emission. Summary of the Invention

[0007] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. The present invention provides a hafnium tantalum zirconium ternary carbide whisker and its preparation method and application.

[0008] In a first aspect of the present invention, a method for preparing hafnium tantalum zirconium ternary carbide whiskers is provided. According to an embodiment of the present invention, the method comprises:

[0009] (1) mixing a metal oxide, a carbon source, and a halide to obtain a precursor powder;

[0010] (2) Using inert gas as protective gas, the precursor powder is subjected to temperature-controlled reaction in a heat treatment furnace to obtain hafnium tantalum zirconium ternary carbide whiskers.

[0011] In some embodiments, the metal oxide is hafnium oxide, tantalum oxide, and zirconium oxide.

[0012] In some embodiments, in step (1), the carbon source includes at least one of carbon nanotubes, activated carbon, and carbon powder.

[0013] In some embodiments, the halide includes at least one of potassium fluoride, sodium fluoride, sodium chloride, and potassium chloride.

[0014] In some embodiments, in step (1), the molar ratio of the metal oxide to the carbon source is 1:(1-4), for example, 1:1, 1:1.5, 1:2, 1:2.5; 1:3; 1:3.5; 1:4, etc.

[0015] In some embodiments, the molar ratio of the halide to the carbon source is (1-2):(1-2), for example, 1:1, 1:1.5, 1:2, 2:1, 2:1.5, etc.

[0016] In some embodiments, before step (1), the metal oxide, carbon source and halide are dried at 80-120° C. for 4-12 hours.

[0017] In some embodiments, in step (1), the temperature-controlled reaction includes: under the protection of an inert gas, heating to T1 at a first rate ν1, and then performing a first heat preservation; then heating to T2 at a second rate ν2, and then performing a second heat preservation; finally cooling to T3 at a third rate ν3, and then turning off the heating power supply to allow the heat treatment furnace to naturally cool to room temperature.

[0018] In some embodiments, ν1 is 6 - 10 °C / min, such as 7, 8, 9 °C / min, etc., T1 is 300 - 500 °C, such as 350, 400, 450 °C, etc., and the first heat preservation time is 1 - 3 h, such as 1.5, 2, 2.5 h, etc.

[0019] In some embodiments, ν2 is 2 - 8 °C / min, such as 3, 4, 5, 6, 7 °C / min, etc., T2 is 1400 - 1700 °C, such as 1450, 1500, 1550, 1600, 1650 °C, etc., and the second heat preservation time is 1 - 3 h, such as 1.5, 2, 2.5 h, etc.

[0020] In some embodiments, ν3 is 3 - 6 °C / min, such as 4, 4.5, 5, 5.5 °C / min, etc., T3 is 300 - 400 °C, such as 320, 340, 360, 380 °C, etc.

[0021] In some embodiments, the flow rate of the inert gas is 20 - 100 mL / min, such as 30, 40, 50, 60, 70, 80, 90 mL / min, etc.

[0022] In some embodiments, before step (2), the heat treatment furnace is evacuated to below 0.1 MPa, and then a protective gas is introduced to restore the furnace to normal pressure.

[0023] In some embodiments, the protective gas includes at least one of nitrogen and argon.

[0024] In the second aspect of the present invention, the present invention provides a hafnium tantalum zirconium ternary carbide whisker, which is prepared by the above method.

[0025] In some embodiments, the chemical formula of the hafnium tantalum zirconium ternary carbide whisker is (Hf x Ta y Zr z )C, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1.

[0026] In some embodiments, the length of the hafnium tantalum zirconium ternary carbide whiskers is 50-400 μm, for example, 100, 150, 200, 250, 300, 350 μm, etc.

[0027] The diameter of the hafnium tantalum zirconium ternary carbide whiskers is 0.5-2 μm, for example, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 μm, etc.

[0028] The aspect ratio of the hafnium tantalum zirconium ternary carbide whiskers is 25 to 800, for example, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, etc.

[0029] In a third aspect of the present invention, the present invention provides a use of the above-mentioned hafnium tantalum zirconium ternary carbide whiskers in the field of ceramic materials and / or microelectronic devices.

[0030] The present invention has the following beneficial effects:

[0031] (1) (Hf x Ta y Zr z )C whiskers are multi-component carbide solid solution structures. They not only inherit the high melting point, high strength and corrosion resistance of single carbide ceramics HfC, TaC, and ZrC, but also have controllable properties due to multi-component solid solution. Lattice distortion occurs during multi-component solid solution, and this solid solution strengthening effect enhances mechanical properties such as hardness and elastic modulus. (Hf x Ta y Zr z )C solid solution also has excellent thermal conductivity, electrical conductivity and anti-oxidation / ablation properties;

[0032] (2) The preparation process of the present invention does not use metal catalysts, which ensures the high purity of the whiskers and can be used for (Hf x Ta y Zr z )C whisker structure, composition, morphology can be regulated, therefore, according to (Hf x Ta y Zr z )C whisker materials are used in different service environments. The composition, structure and distribution of the materials are designed and prepared in a targeted manner to obtain whisker materials with different properties, in order to give full play to the (Hf x Ta y Zr z )C solid solution structure and whisker morphology advantages, to achieve (Hf x Ta y Zr z ) Reliable application of C whiskers;

[0033] (3) (Hf x Ta y Zr z )C vertical growth provides convenience for its application in the field of microelectronics;

[0034] (4) The ultra-high temperature hafnium tantalum zirconium ternary carbide whiskers prepared by this method are ideal reinforcements for composite materials and ultra-high temperature ceramics. They can be used in ceramic-based, carbon-based composite materials and ultra-high temperature ceramic coatings to significantly improve their mechanical properties and anti-oxidation / ablation properties. They also have broad development prospects in the fields of electromagnetic shielding and field emission.

[0035] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The phase composition and structural characterization diagrams of the hafnium tantalum zirconium ternary carbide whiskers prepared in Example 1, wherein (a) is an XRD pattern of the hafnium tantalum zirconium ternary carbide whiskers; (b) is an SEM image of the hafnium tantalum zirconium ternary carbide whiskers;

[0037] Figure 2 This is an SEM image of the hafnium tantalum zirconium ternary carbide whiskers prepared in Example 2;

[0038] Figure 3 These are structural representations of the hafnium, tantalum, and zirconium ternary carbide whiskers prepared in Example 3, wherein (a) is a SEM image of the hafnium, tantalum, and zirconium ternary carbide whiskers; (b) is a high-magnification SEM image of the hafnium, tantalum, and zirconium ternary carbide whiskers; and (c) is a SEM image of the hafnium, tantalum, and zirconium ternary carbide whiskers after heat treatment at 2100°C.

[0039] Figure 4 This is an SEM image of the hafnium tantalum zirconium ternary carbide whiskers prepared in Example 4;

[0040] Figure 5 This is the SEM image of the product prepared in Comparative Example 1;

[0041] Figure 6 This is the SEM image of the product prepared in Comparative Example 2;

[0042] Figure 7 This is the SEM image of the product prepared in Comparative Example 3. DETAILED DESCRIPTION

[0043] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way. In the following examples and comparative examples, unless otherwise specified, the raw materials used are common commercial products that can be directly purchased in the art or prepared according to conventional methods available in the art. Unless otherwise specified, the mixing or reaction temperature is room temperature.

[0044] Example 1

[0045] (1) Weighing HfO2, Ta2O5 and ZrO2 precursor powders with a molar ratio of 3:0.5:1, weighing carbon nanotubes with a total molar ratio of 4:1 to the above precursor powders, and weighing NaF powder with a molar ratio of 2:1 to the carbon nanotubes, placing the above powders in a ball mill on a ball mill, mixing them evenly, and then placing them in a crucible, and placing the crucible in an oven at 80°C for 12 hours for the preparation of hafnium tantalum zirconium ternary carbide whiskers;

[0046] (2) Place the dried mixed powder in the high-temperature heating zone of a heat treatment furnace, evacuate the heat treatment furnace to 0.1 MPa, check that it is airtight, and then introduce Ar to restore the heat treatment furnace to normal pressure;

[0047] (3) After the heat treatment furnace returns to normal pressure, adjust the flow rate of protective gas Ar to 20 ml / min and set the temperature rise and fall program:

[0048] (a) heating the heat treatment furnace to 300°C at a heating rate of 6°C / min, allowing the reaction materials to fully contact at this temperature for 3 hours;

[0049] (b) Heating to 1400°C at a heating rate of 8°C / min and holding for 3 h;

[0050] (4) After cooling to 300°C at a cooling rate of 6°C / min, the heating power is turned off and the heat treatment furnace is allowed to cool to room temperature naturally, thereby obtaining hafnium tantalum zirconium ternary carbide whiskers.

[0051] Figure 1 (a) shows the preparation of the present invention (Hf 3 / 5 Ta 1 / 5 Zr 1 / 5 ) The XRD pattern of C whiskers shows that the characteristic peaks are sharp and symmetrical, with no other impurity peaks, indicating that the whiskers have good crystallinity and high purity.

[0052] Figure 1 (b) shows (Hf 3 / 5 Ta 1 / 5 Zr 1 / 5) SEM image of C whiskers. It can be seen from the figure that the prepared whiskers grow vertically, with a whisker length of 250-330 μm, a diameter of 0.5-1.5 μm, an aspect ratio of 220-660, and an Hf:Ta:Zr element molar ratio of approximately 3:1:1, which is close to the Hf:Ta:Zr molar ratio in the precursor powder feed, indicating that this method can synthesize ternary carbide whiskers with a set ratio.

[0053] Example 2

[0054] (1) Weighing HfO2, Ta2O5 and ZrO2 precursor powders with a molar ratio of 1:0.5:1, weighing carbon nanotubes with a total molar ratio of 1:1 to the above precursor powders, and weighing KF powder with a molar ratio of 1:2 to the carbon nanotubes, placing the above powders in a ball mill on a ball mill, mixing them evenly, and then placing them in a crucible, and placing the crucible in an oven at 80°C for 12 hours for the preparation of hafnium tantalum zirconium ternary carbide whiskers;

[0055] (2) Place the dried mixed powder in the high-temperature heating zone of a heat treatment furnace, evacuate the heat treatment furnace to 0.1 MPa, check that it is airtight, and then introduce Ar to restore the heat treatment furnace to normal pressure;

[0056] (3) After the heat treatment furnace returns to normal pressure, adjust the flow rate of protective gas Ar to 20 ml / min and set the temperature rise and fall program:

[0057] (a) heating the heat treatment furnace to 300°C at a heating rate of 6°C / min, allowing the reaction materials to fully contact at this temperature for 3 hours;

[0058] (b) Heating to 1400°C at a heating rate of 8°C / min and holding for 3 h;

[0059] (4) After cooling to 300°C at a cooling rate of 6°C / min, the heating power is turned off and the heat treatment furnace is allowed to cool to room temperature naturally, thereby obtaining hafnium tantalum zirconium ternary carbide whiskers.

[0060] Figure 2 Shown is (Hf 1 / 3 Ta 1 / 3 Zr 1 / 3 ) SEM image of C whiskers. It can be seen from the figure that the prepared whiskers have a length of 80-240 μm, a diameter of 0.6-1.0 μm, an aspect ratio of 80-400, and an Hf:Ta:Zr element molar ratio of approximately 1:1:1, which is close to the Hf:Ta:Zr molar ratio in the precursor powder feed.

[0061] Example 3

[0062] (1) Weighing HfO2, Ta2O5 and ZrO2 precursor powders with a molar ratio of 1:0.5:1, weighing carbon nanotubes with a total molar ratio of 1:1 to the above precursor powders, and weighing KF powder with a molar ratio of 1:2 to the carbon nanotubes, placing the above powders in a ball mill on a ball mill, mixing them evenly, and then placing them in a crucible, and placing the crucible in a 120°C oven to dry for 4 hours for the preparation of hafnium tantalum zirconium ternary carbide whiskers;

[0063] (2) Place the dried mixed powder in the high-temperature heating zone of a heat treatment furnace, evacuate the heat treatment furnace to 0.1 MPa, check that it is airtight, and then introduce nitrogen to restore the heat treatment furnace to normal pressure;

[0064] (3) After the heat treatment furnace returns to normal pressure, adjust the flow rate of protective gas N2 to 50ml / min and set the temperature rise and fall program:

[0065] (a) The heat treatment furnace was heated to 400°C at a heating rate of 8°C / min, and the reaction materials were kept in contact at this temperature for 2 h;

[0066] (b) Heating to 1550°C at a rate of 5°C / min and holding for 2 h;

[0067] (4) After cooling to 350°C at a cooling rate of 4°C / min, the heating power is turned off and the heat treatment furnace is allowed to cool to room temperature naturally, thereby obtaining hafnium tantalum zirconium ternary carbide whiskers.

[0068] Figure 3 (a) shows (Hf 1 / 3 Ta 1 / 3 Zr 1 / 3 )C Whiskers SEM image shows that the whiskers grow vertically and have a high yield. Figure 3 (b) is a single root (Hf 1 / 3 Ta 1 / 3 Zr 1 / 3 A high-magnification SEM image of the C whiskers shows a smooth surface and uniform diameter with no significant axial variation. The whiskers are approximately 100 to 160 μm in length, 0.8 to 1.5 μm in diameter, and have an aspect ratio of 60 to 200. The Hf:Ta:Zr molar ratio is approximately 1:1:1, which is close to the Hf:Ta:Zr molar ratio in the precursor powder feed.

[0069] The whiskers were subjected to high temperature heat treatment to study their high temperature structure retention rate. Figure 3 (c) shows the SEM image of the whiskers after heat treatment at 2100°C in an inert environment for 2 hours. It can be seen from the figure that after heat treatment, the whiskers still maintain a complete one-dimensional structure and there is no obvious change in diameter along the axial direction, indicating that the whiskers prepared by this method have good high-temperature stability.

[0070] Example 4

[0071] (1) Weighing HfO2, Ta2O5 and ZrO2 precursor powders with a molar ratio of 1:0.5:3, weighing carbon nanotubes with a total molar ratio of 2:1 to the above precursor powders, and weighing KCl powder with a molar ratio of 1:1 to the carbon nanotubes, placing the above powders in a ball mill on a ball mill and mixing them evenly, and then placing them in a crucible, and placing the crucible in an oven at 100°C for 8 hours for the preparation of hafnium tantalum zirconium ternary carbide whiskers;

[0072] (2) Place the dried mixed powder in the high-temperature heating zone of a heat treatment furnace, evacuate the heat treatment furnace to 0.1 MPa, check that it is airtight, and then introduce Ar to restore the heat treatment furnace to normal pressure;

[0073] (3) After the heat treatment furnace returns to normal pressure, adjust the flow rate of protective gas Ar to 100 ml / min and set the temperature rise and fall program:

[0074] (a) heating the heat treatment furnace to 500°C at a heating rate of 10°C / min, allowing the reaction materials to fully contact at this temperature for 1 hour;

[0075] (b) Heating to 1700°C at a rate of 2°C / min and holding for 1 h;

[0076] (4) After cooling to 400°C at a cooling rate of 3°C / min, the heating power is turned off and the heat treatment furnace is allowed to cool to room temperature naturally, thereby obtaining hafnium tantalum zirconium ternary carbide whiskers.

[0077] Figure 4 Shown is (Hf 1 / 5 Ta 1 / 5 Zr 3 / 5 ) SEM images of C whiskers show uniform distribution, no apparent agglomeration, and no impurities, demonstrating high whisker yield and purity. The whiskers grown vertically ranged from 120 to 180 μm in length, 1.5 to 2 μm in diameter, and an aspect ratio of 60 to 120. The Hf:Ta:Zr molar ratio was approximately 1:1:3, close to the Hf:Ta:Zr molar ratio in the precursor powder feed.

[0078] Comparative Example 1

[0079] The heating process (a) in step (3) was omitted, and the other steps were the same as in Example 3 to obtain the product.

[0080] Figure 5 This is the SEM image of the product prepared by the above method. It can be seen from the figure that there are a large number of ceramic blocks accumulated in the prepared product, while only a very small number of whiskers are generated on the surface of the ceramic blocks. The whiskers grow in a disorderly manner and the surface is relatively rough.

[0081] Comparative Example 2

[0082] The heating process in step (3) (b) was changed to: heating to 1300° C. at a heating rate of 8° C. / min and holding time of 3 h. Other steps were the same as those in Example 1 to obtain the product.

[0083] Figure 6 This is the SEM image of the prepared product. It can be seen from the figure that when the preparation temperature is 1300℃, no one-dimensional material is generated and the product is a sintered ceramic block.

[0084] Comparative Example 3

[0085] The carbon nanotubes were weighed in a total molar ratio of 1:4 to the precursor powder, and the other steps were the same as those in Example 3 to obtain the product.

[0086] Figure 7 This is the SEM image of the prepared product. It can be seen from the figure that when the carbon source precursor powder is reduced, a large number of ceramic blocks are generated in the prepared product, and only a small amount of whiskers are generated in the gaps between the ceramic blocks.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing hafnium tantalum zirconium ternary carbide whiskers, characterized in that: The method comprises: (1) mixing a metal oxide, a carbon source, and a halide to obtain a precursor powder; (2) subjecting the precursor powder to a temperature-controlled reaction in a heat treatment furnace to obtain hafnium tantalum zirconium ternary carbide whiskers; The metal oxides are hafnium oxide, tantalum oxide and zirconium oxide.

2. The method according to claim 1, characterized in that In step (1), the carbon source includes at least one of carbon nanotubes, activated carbon and carbon powder; and / or, The halide includes at least one of potassium fluoride, sodium fluoride, sodium chloride and potassium chloride.

3. The method according to claim 1, characterized in that In step (1), the molar ratio of the metal oxide to the carbon source is 1:(1-4); and / or, The molar ratio of the halide to the carbon source is (1-2): (1-2).

4. The method according to claim 1, wherein In step (1), the temperature control reaction includes: under the protection of inert gas, heating to T1 at a first rate ν1, and then performing a first heat preservation; then heating to T2 at a second rate ν2, and then performing a second heat preservation; finally cooling to T3 at a third rate ν3, and then turning off the heating power to allow the heat treatment furnace to naturally cool to room temperature.

5. The method according to claim 4, characterized in that The ν1 is 6 to 10°C / min, the T1 is 300 to 500°C, and the first holding time is 1 to 3 hours; and / or, The ν2 is 2 to 8°C / min, the T2 is 1400 to 1700°C, and the second holding time is 1 to 3 hours; and / or, The ν3 is 3-6°C / min, the T3 is 300-400°C; and / or, The flow rate of the inert gas is 20-100 mL / min.

6. The method according to claim 1, characterized in that Before step (1), the metal oxide, carbon source and halide are dried at 80-120° C. for 4-12 hours; and / or, Before step (2), the heat treatment furnace is evacuated to below 0.1 MPa, and then protective gas is introduced to restore the furnace to normal pressure.

7. A hafnium tantalum zirconium ternary carbide whisker, characterized in that: The hafnium tantalum zirconium ternary carbide whiskers are prepared by the method according to any one of claims 1 to 6.

8. The ternary carbide whisker according to claim 7, characterized in that: The chemical formula of the whisker is (Hf x Ta y Zr z )C, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1.

9. The ternary carbide whisker according to claim 7, characterized in that: The length of the whiskers is 50 to 400 μm; and / or, The diameter of the whiskers is 0.5 to 2 μm; and / or, The aspect ratio of the whiskers is 25-800.

10. Use of the ternary carbide whisker according to any one of claims 7 to 9 in the field of ceramic materials and / or microelectronic devices.

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