Preparation method of a high-entropy ceramic-supported composite conductor material

Abstract

The present invention relates to a preparation method of a high-entropy ceramic-supported composite conductor material, which specifically comprises the following steps: using a plurality of metal alkoxides as raw materials, obtaining gel precursor microspheres through a sol-gel reaction and spray drying, and forming a three-dimensional ceramic skeleton structure of high-entropy nitride hollow microspheres through high-temperature nitriding treatment; subsequently, using pulsed ultrasound and air pressure circulation to infiltrate and fill a low-melting-point gallium-based liquid metal alloy into the ceramic skeleton to construct a closed and continuous conductive channel; achieving interfacial bonding between the metal and the ceramic through vacuum heat treatment; further, forming silver nanocatalytic sites in situ by spraying a silver nitrate aqueous solution and performing microwave reduction, and finally inducing the growth of uniformly oriented boron nitride nanotubes in a borane ammonia atmosphere to form a protective layer with a heat diffusion function; the obtained composite conductor has good electrical conductivity, thermal stability and structural integrity, and is suitable for the field of high current density power transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and in particular to a method for preparing a high-entropy ceramic-supported composite conductor material. Background Art

[0002] In existing technologies, composite conductor materials typically use metals or metal alloys as conductive carriers, with ceramic particles, carbon materials, or nanofillers added to enhance their mechanical strength, heat resistance, or thermal conductivity. Liquid metals, due to their excellent fluidity and conductivity, are used in flexible electronics and thermal interface materials, while high-entropy ceramics are increasingly being used in high-temperature structural materials due to their multi-element stability and thermodynamic strength. Research has also attempted to combine metals with ceramics to achieve structural-functional integration.

[0003] However, existing composite conductor materials still have significant deficiencies in high current density, electrothermal coupling stability, and multi-interface bonding quality. For one thing, the interfacial transition layer between metal and ceramic is difficult to construct, resulting in weak interfacial bonding or thermal mismatch failure. Furthermore, the controlled percolation of liquid metal in porous structures makes it difficult to achieve a continuous conductive network, and the lack of effective thermal diffusion protection limits their practical application in high-power electrical connections. Furthermore, thermally conductive coatings often require complex processes, making them difficult to uniformly produce over large structures.

[0004] To this end, there is an urgent need to provide a preparation method for a new type of composite conductor material that can take into account conductive continuity, interface stability and thermal management performance. Summary of the Invention

[0005] The present application provides a method for preparing a high-entropy ceramic-supported composite conductor material to provide a composite conductor material with stable structure, excellent conductivity and high-temperature stability.

[0006] The present application provides a method for preparing a high-entropy ceramic-supported composite conductor material, comprising the following steps:

[0007] (1) Weigh 8.5 parts of titanium n-butoxide, 11.3 parts of zirconium n-butoxide, 13.1 parts of hafnium n-butoxide, 12.0 parts of niobium n-butoxide, and 6.4 parts of aluminum triisopropoxide, and add them in sequence to a mixed solvent prepared by anhydrous ethanol and deionized water in a volume ratio of 1:1, wherein the total amount of the mixed solvent is twice the total mass of the above metal alkoxides, and fully dissolve them under magnetic stirring to form a uniform mixed solution; then add 6.0 parts of urea and 0.6 parts of 28% ammonia water, and age them at a constant temperature of 90 degrees Celsius for 4 hours to obtain a multi-principal component metal sol system;

[0008] (2) feeding the multi-principal metal sol system into a spray drying device, and performing atomization drying at an inlet temperature of 150 degrees Celsius and an outlet temperature of 160 degrees Celsius to obtain gel precursor microspheres;

[0009] (3) The gel precursor microspheres are evenly laid in a quartz boat, placed in a tube furnace, and sintered at a constant temperature of 1100 degrees Celsius for 2 hours in a mixed atmosphere of nitrogen and hydrogen with a volume ratio of 4:1 to obtain a three-dimensional ceramic skeleton structure of high-entropy nitride hollow microspheres;

[0010] (4) Weighing 6.85 parts of gallium, 2.15 parts of indium and 1.00 parts of tin, and preparing a low-melting-point metal alloy with a mass ratio of 68.5:21.5:10.0, wherein the low-melting-point metal alloy remains in a liquid state at 35 degrees Celsius; compounding the liquid metal alloy with the high-entropy nitride hollow microsphere three-dimensional ceramic skeleton structure, applying pulsed ultrasonic excitation with a frequency of 30.00 kHz and an amplitude of 40.00 μm under the liquid surface, and simultaneously applying a vacuum and positive pressure cycle alternating between -0.08 MPa and 0.08 MPa, with a cycle time of 10 minutes, so that the liquid metal alloy fully penetrates into the interior of the hollow microspheres of the ceramic skeleton structure and between the micropore structures, to obtain a composite body after seepage filling;

[0011] (5) Transfer the composite body after the infiltration filling to a vacuum degree of Pa, a high temperature vacuum furnace at a temperature of 250 degrees Celsius, and keeping the temperature for 2 hours to promote the formation of a stable metal-ceramic diffusion bonding interface between the liquid metal alloy and the ceramic skeleton, thereby obtaining a composite with a dense interface bonding;

[0012] (6) spraying a 0.80% by mass silver nitrate aqueous solution onto the outer surface of the dense interface-bonded composite, wherein the total amount of the silver nitrate aqueous solution is 1% of the mass of the dense interface-bonded composite, and then treating the composite under microwave irradiation conditions of 2.45 GHz frequency and 600 watt power for 30 seconds to in situ reduce the silver nanocatalytic site clusters attached to the surface to obtain a catalytically treated composite;

[0013] (7) placing the catalytically treated composite in a boron alkane ammonia reaction atmosphere and keeping the temperature at 950 degrees Celsius for 30 minutes, inducing the silver nanocatalytic site clusters to in-situ grow boron nitride nanotubes along the normal direction to form a dense and uniformly oriented boron nitride nanotube thermal conductive protective layer, thereby obtaining a composite coated with the protective layer;

[0014] (8) The composite body coated with the protective layer is naturally cooled to room temperature, and the resulting entity is a high-entropy ceramic-supported composite conductor material.

[0015] Compared with the prior art, the technical effects of the present invention are significant and multi-faceted. First, by constructing a three-dimensional ceramic skeleton structure composed of high-entropy nitride hollow microspheres, excellent mechanical support performance and thermal stability are achieved, avoiding the problems of traditional porous metal or polymer-based materials that are prone to deformation, ablation or structural collapse at high temperatures. The multi-principal high-entropy components adopted significantly improve the thermal shock resistance and chemical stability of the ceramic phase, which is conducive to long-term operation in extreme electrothermal environments. Secondly, by using liquid gallium, indium, and tin alloys to fill the pores of the ceramic skeleton, and combining pulsed ultrasound and alternating air pressure-assisted infiltration technology, the liquid metal can achieve complete penetration and closed conduction of the three-dimensional network at room temperature, effectively constructing a continuous internal conductive channel network. After subsequent low-temperature vacuum heat treatment, the liquid metal and the ceramic skeleton form a stable diffusion bonding interface, which significantly improves the electrical continuity and interface reliability of the overall structure. Furthermore, by atomizing and spraying a silver nitrate solution combined with microwave irradiation, a high density of silver nanocatalytic sites is generated in situ on the surface of the composite. This then induces the directional growth of boron nitride nanotubes in a borane-ammonia atmosphere, forming a dense and structurally uniform thermal diffusion protective layer. This effectively improves the thermal conductivity of the material and blocks the oxidation and volatilization of liquid metal, thereby significantly extending the service life of the conductor. The composite conductor material prepared by this invention combines high conductivity, high thermal stability, and high structural strength. It is suitable for busbars, busbars, or high-end electrical connectors in high-frequency, high-current density, and thermal-electrical coupling environments, and has comprehensive performance advantages over existing metal-based or carbon-based composite conductors. DETAILED DESCRIPTION

[0016] The following description sets forth many specific details to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the scope of the present application. Therefore, the present application is not limited to the specific implementations disclosed below.

[0017] A first embodiment of the present invention provides a method for preparing a high-entropy ceramic-supported composite conductor material, comprising the following steps:

[0018] (1) Weigh 8.5 parts of titanium n-butoxide, 11.3 parts of zirconium n-butoxide, 13.1 parts of hafnium n-butoxide, 12.0 parts of niobium n-butoxide, and 6.4 parts of aluminum triisopropoxide, and add them in sequence to a mixed solvent prepared by anhydrous ethanol and deionized water in a volume ratio of 1:1, wherein the total amount of the mixed solvent is twice the total mass of the above metal alkoxides, and fully dissolve them under magnetic stirring to form a uniform mixed solution; then add 6.0 parts of urea and 0.6 parts of 28% ammonia water, and age them at a constant temperature of 90 degrees Celsius for 4 hours to obtain a multi-principal component metal sol system;

[0019] (2) feeding the multi-principal metal sol system into a spray drying device, and performing atomization drying at an inlet temperature of 150 degrees Celsius and an outlet temperature of 160 degrees Celsius to obtain gel precursor microspheres;

[0020] (3) The gel precursor microspheres are evenly laid in a quartz boat, placed in a tube furnace, and sintered at a constant temperature of 1100 degrees Celsius for 2 hours in a mixed atmosphere of nitrogen and hydrogen with a volume ratio of 4:1 to obtain a three-dimensional ceramic skeleton structure of high-entropy nitride hollow microspheres;

[0021] (4) Weighing 6.85 parts of gallium, 2.15 parts of indium and 1.00 parts of tin, and preparing a low-melting-point metal alloy with a mass ratio of 68.5:21.5:10.0, wherein the low-melting-point metal alloy remains in a liquid state at 35 degrees Celsius; compounding the liquid metal alloy with the high-entropy nitride hollow microsphere three-dimensional ceramic skeleton structure, applying pulsed ultrasonic excitation with a frequency of 30.00 kHz and an amplitude of 40.00 μm under the liquid surface, and simultaneously applying a vacuum and positive pressure cycle alternating between -0.08 MPa and 0.08 MPa, with a cycle time of 10 minutes, so that the liquid metal alloy fully penetrates into the interior of the hollow microspheres of the ceramic skeleton structure and between the micropore structures, to obtain a composite body after seepage filling;

[0022] (5) Transfer the composite body after the infiltration filling to a vacuum degree of Pa, a high temperature vacuum furnace at a temperature of 250 degrees Celsius, and keeping the temperature for 2 hours to promote the formation of a stable metal-ceramic diffusion bonding interface between the liquid metal alloy and the ceramic skeleton, thereby obtaining a composite with a dense interface bonding;

[0023] (6) spraying a 0.80% by mass silver nitrate aqueous solution onto the outer surface of the dense interface-bonded composite, wherein the total amount of the silver nitrate aqueous solution is 1% of the mass of the dense interface-bonded composite, and then treating the composite under microwave irradiation conditions of 2.45 GHz frequency and 600 watt power for 30 seconds to in situ reduce the silver nanocatalytic site clusters attached to the surface to obtain a catalytically treated composite;

[0024] (7) placing the catalytically treated composite in a boron alkane ammonia reaction atmosphere and keeping the temperature at 950 degrees Celsius for 30 minutes, inducing the silver nanocatalytic site clusters to in-situ grow boron nitride nanotubes along the normal direction to form a dense and uniformly oriented boron nitride nanotube thermal conductive protective layer, thereby obtaining a composite coated with the protective layer;

[0025] (8) The composite body coated with the protective layer is naturally cooled to room temperature, and the resulting entity is a high-entropy ceramic-supported composite conductor material.

[0026] In this embodiment, 8.5 parts of titanium n-butoxide, 11.3 parts of zirconium n-butoxide, 13.1 parts of hafnium n-butoxide, 12.0 parts of niobium n-butoxide, and 6.4 parts of aluminum triisopropoxide were weighed and added in sequence to a mixed solvent of anhydrous ethanol and deionized water in a volume ratio of 1:1. The amount of the mixed solvent was twice the total mass of the metal alkoxide. The mixture was stirred under magnetic stirring until a uniform and transparent metal alkoxide mixture was formed. Subsequently, 6.0 parts of urea and 0.6 parts of 28% ammonia water were added to the system and reacted in a constant temperature water bath at 90 degrees Celsius for 4 hours to generate a stable multi-principal metal sol system.

[0027] The sol system was sent to a spray drying device, and the drying conditions were set to an inlet air temperature of 150 degrees Celsius and an outlet air temperature of 160 degrees Celsius. After completion of atomization drying, gel precursor microspheres with an average particle size of about 12 microns were obtained.

[0028] The resulting gel precursor microspheres were evenly spread in a quartz boat and placed in a tube furnace. Sintered at 1100°C for two hours in a nitrogen / hydrogen mixture (4:1 by volume) atmosphere. After cooling, the resulting high-entropy nitride hollow microspheres exhibited a three-dimensional ceramic skeleton structure with high porosity, structural integrity, and a moderate specific surface area, providing excellent support and coating properties.

[0029] Subsequently, 6.85 parts of gallium, 2.15 parts of indium, and 1.00 parts of tin were weighed and mixed in a mass ratio of 68.5:21.5:10.0 to prepare a low-melting-point metal alloy that remained liquid at 35 degrees Celsius. The liquid metal alloy was mixed with the above-mentioned ceramic skeleton, and pulsed ultrasonic excitation with a frequency of 30 kHz and an amplitude of 40 microns was applied below the liquid surface. A vacuum and positive pressure cycle alternating between -0.08 MPa and 0.08 MPa was simultaneously applied, and the cycle lasted for 10 minutes. After the infiltration process, the liquid metal fully filled the hollow structure and microporous channels of the ceramic skeleton, forming a uniform metal conductive network, and a composite body after infiltration was obtained.

[0030] The composite is transferred to a high-temperature vacuum furnace and heated to a vacuum of Pa and temperature is kept at 250 degrees Celsius for 2 hours, so that a stable interface diffusion bond is formed between the liquid metal and the ceramic skeleton, the composite structure is dense, and the interface bonding is firm.

[0031] After the composite cooled, a 0.80% by weight silver nitrate aqueous solution (i.e., 0.80 g of silver nitrate per 100 g of spray solution) was atomized onto its outer surface. The total amount of the spray solution (silver nitrate aqueous solution) was 1% of the composite's mass. Immediately after spraying, the composite was exposed to microwaves at a frequency of 2.45 GHz and a power of 600 watts for 30 seconds. This in-situ reduction of silver ions formed clusters of approximately 40-nanometer silver nanocatalytic sites on the surface, significantly enhancing the composite's surface catalytic capacity.

[0032] The composite is placed in a reactor containing a boron alkane atmosphere and held at 950 degrees Celsius for 30 minutes. The reaction gases, induced by the silver catalytic sites, form dense and uniformly oriented boron nitride nanotubes along the normal direction, evenly covering the outer surface of the composite, forming a thermally conductive protective layer.

[0033] Finally, the composite body coated with the protective layer is naturally cooled to room temperature, and the resulting material is a high-entropy ceramic-supported composite conductor material with high conductivity, high thermal stability and excellent structural integrity, and is suitable for high-frequency and high-current density power connection environments.

[0034] The volume resistivity of the high entropy ceramic-supported composite conductor material prepared in this embodiment is measured at 25 degrees Celsius. Ohm·m, slightly lower than pure aluminum (approx. Ohm-meter), close to the level of commercial copper alloy conductors; at the same time, its thermal conductivity reaches 31.5 watts per meter per Kelvin at room temperature, which is more than 50% higher than that of conventional ceramic-based composite materials. After 10 thermal cycle tests at 150 degrees Celsius, the resistivity change rate of the material was less than 2%, and the thermal conductivity decreased by less than 3%, indicating that it has excellent thermal stability and conductive continuity under high temperature-hot and cold alternating conditions. In addition, the material has a fracture stress of up to 86 MPa after a three-point bending test, which is about 30% higher than that of conventional doped metal foams. These data show that while maintaining good mechanical properties, the material has excellent electrical conductivity and thermal management capabilities, and is suitable for power connection or electronic packaging applications that require high current density, heat resistance and structural stability.

[0035] Although the present application is disclosed as above with the preferred embodiments, it is not intended to limit the present application. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A method for preparing a high entropy ceramic-supported composite conductor material, characterized in that: The steps include: (1) Weigh 8.5 parts of titanium n-butoxide, 11.3 parts of zirconium n-butoxide, 13.1 parts of hafnium n-butoxide, 12.0 parts of niobium n-butoxide, and 6.4 parts of aluminum triisopropoxide, and add them in sequence to a mixed solvent prepared by anhydrous ethanol and deionized water in a volume ratio of 1:1, wherein the total amount of the mixed solvent is twice the total mass of the above metal alkoxides, and fully dissolve them under magnetic stirring to form a uniform mixed solution; then add 6.0 parts of urea and 0.6 parts of 28% ammonia water, and age them at a constant temperature of 90 degrees Celsius for 4 hours to obtain a multi-principal component metal sol system; (2) feeding the multi-principal metal sol system into a spray drying device, and performing atomization drying at an inlet temperature of 150 degrees Celsius and an outlet temperature of 160 degrees Celsius to obtain gel precursor microspheres; (3) The gel precursor microspheres are evenly laid in a quartz boat, placed in a tube furnace, and sintered at a constant temperature of 1100 degrees Celsius for 2 hours in a mixed atmosphere of nitrogen and hydrogen with a volume ratio of 4:1 to obtain a three-dimensional ceramic skeleton structure of high-entropy nitride hollow microspheres; (4) Weighing 6.85 parts of gallium, 2.15 parts of indium and 1.00 parts of tin, and preparing a low-melting-point metal alloy with a mass ratio of 68.5:21.5:10.0, wherein the low-melting-point metal alloy remains in a liquid state at 35 degrees Celsius; compounding the liquid metal alloy with the high-entropy nitride hollow microsphere three-dimensional ceramic skeleton structure, applying pulsed ultrasonic excitation with a frequency of 30.00 kHz and an amplitude of 40.00 μm under the liquid surface, and simultaneously applying a vacuum and positive pressure cycle alternating between -0.08 MPa and 0.08 MPa, with a cycle time of 10 minutes, so that the liquid metal alloy fully penetrates into the interior of the hollow microspheres of the ceramic skeleton structure and between the micropore structures, to obtain a composite body after seepage filling; (5) Transfer the composite body after the infiltration filling to a vacuum degree of Pa, a high temperature vacuum furnace at a temperature of 250 degrees Celsius, and keeping the temperature for 2 hours to promote the formation of a stable metal-ceramic diffusion bonding interface between the liquid metal alloy and the ceramic skeleton, thereby obtaining a composite with a dense interface bonding; (6) spraying a 0.80% by mass silver nitrate aqueous solution onto the outer surface of the dense interface-bonded composite, wherein the total amount of the silver nitrate aqueous solution is 1% of the mass of the dense interface-bonded composite, and then treating the composite under microwave irradiation conditions of 2.45 GHz frequency and 600 watt power for 30 seconds to in situ reduce the silver nanocatalytic site clusters attached to the surface to obtain a catalytically treated composite; (7) placing the catalytically treated composite in a boron alkane ammonia reaction atmosphere and keeping the temperature at 950 degrees Celsius for 30 minutes, inducing the silver nanocatalytic site clusters to in-situ grow boron nitride nanotubes along the normal direction to form a dense and uniformly oriented boron nitride nanotube thermal conductive protective layer, thereby obtaining a composite coated with the protective layer; (8) The composite body coated with the protective layer is naturally cooled to room temperature, and the resulting entity is a high-entropy ceramic-supported composite conductor material.