阅读说明：本技术 一种高导热金属基碳纤维发热体材料的制备方法 (Preparation method of high-thermal-conductivity metal-based carbon fiber heating body material ) 是由 刘翔 于 2020-12-07 设计创作，主要内容包括：本发明专利提供了一种高导热金属基碳纤维发热体材料的制备方法,具体涉及金属基碳纤维材料领域。该高导热金属基碳纤维发热体材料的制备方法包括：通过微波辐射超声氧化法制备具有表面活性的碳纤维粉体；通过熔盐法在所述碳纤维粉体的表面包覆碳化物,制备得到包覆型碳纤维粉体；通过热压法将包覆型碳纤维粉体和合金粉体压制成发热针形状,制备得到发热体材料。使用金属基碳纤维材料制备的发热体外壳能够结合碳纤维材料高导热特性和金属材料高强度特性,提高发热体的导热效率,同时能够降低外壳的热膨胀系数,提高材料的使用性能。(The invention provides a preparation method of a high-heat-conductivity metal-based carbon fiber heating body material, and particularly relates to the field of metal-based carbon fiber materials. The preparation method of the high-thermal-conductivity metal-based carbon fiber heating body material comprises the following steps: preparing carbon fiber powder with surface activity by a microwave radiation ultrasonic oxidation method; coating carbide on the surface of the carbon fiber powder by a molten salt method to prepare coated carbon fiber powder; and pressing the coated carbon fiber powder and the alloy powder into a heating needle shape by a hot pressing method to prepare the heating body material. The heating element shell prepared by using the metal-based carbon fiber material can combine the high heat conduction characteristic of the carbon fiber material and the high strength characteristic of the metal material, improve the heat conduction efficiency of the heating element, reduce the thermal expansion coefficient of the shell and improve the service performance of the material.)

1. A preparation method of a high-thermal-conductivity metal-based carbon fiber heating body material is characterized by comprising the following steps:

preparing carbon fiber powder with surface activity by a microwave radiation ultrasonic oxidation method;

coating carbide on the surface of the carbon fiber powder by a molten salt method to prepare coated carbon fiber powder;

and pressing the coated carbon fiber powder and the alloy powder into a heating needle shape by a hot pressing method to prepare the heating material.

2. The method for producing a metal-based carbon fiber heat-generating body material with high thermal conductivity as described in claim 1,

the microwave radiation ultrasonic oxidation method comprises the following specific steps: selecting carbon fibers to be invaded into the oxide solution, enabling the carbon fibers to be completely dispersed in the solution, putting the solution into a microwave oven for radiation treatment, simultaneously mixing the solution by using ultrasonic waves, and taking out a sample to be washed to be neutral by deionized water after the ultrasonic oxidation is finished.

3. A preparation method of a high thermal conductivity metal-based carbon fiber heating element material as claimed in claim 2, wherein the oxide is at least one of hydrogen peroxide, ozone and potassium permanganate, and the concentration range used is 2% -8%;

and/or the carbon fiber is at least one of chopped PAN series carbon fiber, pitch series carbon fiber and activated carbon fiber, the average diameter of the carbon fiber is 5-15 μm, and the length of the carbon fiber is 0.2-2 mm.

4. A method for preparing a metal-based carbon fiber heating element material with high thermal conductivity as claimed in claim 2, wherein the microwave radiation is used at a frequency of 1500MHz to 3000MHz for a radiation time of 1s to 1000 s; the ultrasonic frequency range is 10 KHz-50 KHz, and the ultrasonic time is 1 s-1000 s.

5. The method for producing a metal-based carbon fiber heat-generating body material with high thermal conductivity as described in claim 1,

the method for coating the carbide on the surface of the carbon fiber powder by the molten salt method specifically comprises the following steps:

mixing Ti powder and the carbon fiber powder with surface activity to obtain a mixture;

adding molten salt with the same mass into the mixture, and mixing by using a high-energy ball mill, wherein the ball milling medium is absolute ethyl alcohol; and (3) putting the uniformly mixed raw materials into a crucible, introducing argon atmosphere into the crucible, heating the crucible by using microwave, cooling the crucible along with a furnace, and boiling and washing the crucible by using deionized running water to obtain the coated carbon fiber powder.

6. The method for preparing a metal-based carbon fiber heating element material with high thermal conductivity as claimed in claim 5, wherein the thickness of the carbide layer coated on the surface of the carbon fiber powder is 100nm to 130 nm.

7. A method for preparing a metal-based carbon fiber heating element material with high thermal conductivity as claimed in claim 5, wherein the molten salt is at least one of NaCl, KCl, NaF, KF, NaBr and KBr, and has an average particle diameter of 1 μm to 5 μm;

and/or, the molar ratio of the Ti powder to the carbon fiber powder with surface activity is 1: (4.0-4.2).

8. The method for producing a metal-based carbon fiber heat-generating body material with high thermal conductivity as described in claim 1,

and crushing the coated carbon fiber powder into carbon fiber powder with the average particle size of 10-50 mu m, mixing the carbon fiber powder with alloy powder, prepressing the mixture into a heating needle or heating rod shape, and performing hot-pressing sintering to obtain the heating material.

9. The preparation method of the metal-based carbon fiber heating element material with high thermal conductivity as claimed in claim 8, wherein the alloy powder is a mixture of Ti powder and Al powder or a mixture of Cu powder and Mg powder, and the mixing molar ratio is (2.8-3): (0.8 to 1.1),

or the alloy powder is formed by mixing Ti powder, Al powder and Cu powder or Ti powder, Al powder and Mg powder, and the mixing molar ratio is (2.5-3): (0.5-0.8): (0.2-0.4),

and the molar ratio of the alloy powder to the coated carbon fiber powder is 1: (1-2);

and the average grain diameter of the alloy powder is 5-50 μm.

10. A high thermal conductive metal-based carbon fiber heating case prepared from the high thermal conductive metal-based carbon fiber heating element material according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of metal-based carbon fiber materials, in particular to a preparation method of a high-heat-conductivity metal-based carbon fiber heating body material.

Background

Carbon fibers are fiber materials which are carbonized at a high temperature and contain more than 85% of carbon, including carbon fibers and graphite fibers, and are the most important reinforcing materials of composite materials in recent years as high-performance fibers with the characteristics of high specific strength, high specific modulus, small thermal expansion coefficient, low friction coefficient, good low-temperature resistance and the like, and are widely applied to aerospace and sports goods. The carbon fiber has inert surface, small specific surface area, less active carbon atoms at the edge, low surface energy, poor interface performance of other materials and low shearing strength of the composite material layer, thereby restricting the further popularization and application of the field of the carbon fiber composite material. At present, ceramic materials and metal materials are generally adopted as heat conducting shells of heating needles in heat conducting materials of non-burning atomizers, and the materials of the type have the disadvantages of large heat loss, small heating area, uneven temperature distribution and the like in the heat conducting process.

In order to improve the heating efficiency and the temperature distribution uniformity of the metal or ceramic heating needle used at present and improve the heating effect of the heating element, the invention provides a composite material combining carbon fiber and a metal material as a heat conduction material of the heating element, and solves the problems. In order to improve the surface activity of the carbon fiber, reduce the treatment time, improve the coating uniformity of the surface of the carbon fiber and improve the composite effect of the carbon fiber and a metal material, so that the carbon fiber material can not be oxidized at high temperature. The invention provides a method for increasing the active carbon atomic weight on the surface of carbon fiber by using microwave radiation combined with an ultrasonic method, thereby improving the surface coating characteristic of the carbon fiber, and secondly, improving the sintering density of the material by adopting a vacuum hot-pressing sintering technology, thereby obtaining the high-heat-conductivity metal-based carbon fiber composite material.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a preparation method of a high-heat-conductivity metal-based carbon fiber heating element material, which solves at least one technical problem provided by the background technology.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

the invention provides a preparation method of a high-heat-conductivity metal-based carbon fiber heating element material, which comprises the following steps:

preparing carbon fiber powder with surface activity by a microwave radiation ultrasonic oxidation method;

coating carbide on the surface of the carbon fiber powder by a molten salt method to prepare coated carbon fiber powder;

and pressing the coated carbon fiber powder and the alloy powder into a heating needle shape by a vacuum hot pressing method to prepare the heating body material.

Preferably, the microwave radiation ultrasonic oxidation method specifically comprises the following steps: selecting carbon fibers to be invaded into the oxide solution, enabling the carbon fibers to be completely dispersed in the solution, putting the solution into a microwave oven for radiation treatment, simultaneously mixing the solution by using ultrasonic waves, and taking out a sample after the microwave ultrasonic oxidation is finished, and washing the sample to be neutral by using deionized water.

Preferably, the oxide is at least one of hydrogen peroxide, ozone and potassium permanganate, and the used concentration range is 2-8%;

and/or the carbon fiber is at least one of chopped PAN series carbon fiber, pitch series carbon fiber and activated carbon fiber, the average diameter of the carbon fiber is 5-15 μm, and the length of the carbon fiber is 0.2-2 mm.

Preferably, the frequency of the microwave radiation is 1500 MHz-3000 MHz, and the radiation time is 1 s-1000 s; the ultrasonic frequency range is 10 KHz-50 KHz, and the ultrasonic time is 1 s-1000 s.

Preferably, the coating of the carbide on the surface of the carbon fiber powder by the molten salt method specifically comprises the following steps:

mixing Ti powder and the carbon fiber powder with surface activity to obtain a mixture;

adding molten salt with the same mass into the mixture, and mixing by using a high-energy ball mill, wherein the ball milling medium is absolute ethyl alcohol; and (3) putting the uniformly mixed raw materials into a crucible, introducing argon atmosphere into the crucible, heating the crucible by using microwave, cooling the crucible along with a furnace, and boiling and washing the crucible by using deionized running water to obtain the coated carbon fiber powder.

Preferably, the thickness of the carbide layer coated on the surface of the carbon fiber powder is 100nm to 130 nm.

Preferably, the molten salt is at least one of NaCl, KCl, NaF, KF, NaBr and KBr, and the average particle size is 1-5 μm;

and/or, the molar ratio of the Ti powder to the carbon fiber powder with surface activity is 1: (4.0-4.2).

Preferably, the coated carbon fiber powder is crushed into carbon fiber powder with the average particle size of 10-50 μm, the carbon fiber powder and the alloy powder are mixed, pre-pressed into a heating needle or heating rod shape, and hot-pressed and sintered to obtain the heating material.

Preferably, the alloy powder is formed by mixing Ti powder and Al powder or mixing Cu powder and Mg powder, and the mixing molar ratio is (2.8-3): (0.8 to 1.1),

or the alloy powder is formed by mixing Ti powder, Al powder and Cu powder or Ti powder, Al powder and Mg powder, and the mixing molar ratio is (2.5-3): (0.5-0.8): (0.2-0.4),

and the molar ratio of the alloy powder to the coated carbon fiber powder is 1: (1-2);

and the average grain diameter of the alloy powder is 5-50 μm.

The invention also provides a high-heat-conductivity metal-based carbon fiber heating element shell prepared from any one of the high-heat-conductivity metal-based carbon fiber heating element materials.

(III) advantageous effects

The invention provides a preparation method of a high-heat-conductivity metal-based carbon fiber heating element material, which has the following beneficial effects compared with the prior art:

(1) the invention increases the number of the activated carbon atoms on the surface of the carbon fiber by a microwave radiation ultrasonic oxidation method, reduces the number of carbon-carbon double bonds and carbon-carbon single bonds on the surface of the carbon fiber, and provides reaction sites for later coating. Microwave treatment in combination with ultrasound can provide more energy for the reaction. When ultrasonic vibration is transmitted into liquid, strong cavitation effect is excited in the liquid due to the high sound intensity, so that a large amount of cavitation bubbles are generated in the liquid. Along with the generation and the explosion of the cavitation bubbles, micro-jet flow is generated to break down carbon fiber granules in the liquid, so that the surface of the carbon fiber can be more fully subjected to oxidation reaction with hydrogen peroxide, and the oxidation reaction can be greatly promoted under the action of ultrasound.

(2) TiC has a high elastic modulus, high strength, good thermal and electrical conductivity, and is a very widely used ceramic coating. The surface of the carbon fiber is subjected to activation of microwave irradiation and ultrasonic combination, so that the TiC coating layer can be uniformly and compactly attached to the surface of the carbon fiber without falling off, and the internal carbon fiber can be protected from being oxidized due to heat conduction at high temperature.

(3) The heating element shell prepared by using the metal-based carbon fiber material can combine the high heat conduction characteristic of the carbon fiber material and the high strength characteristic of the metal material, improve the heat conduction efficiency of the heating element, reduce the thermal expansion coefficient of the shell and improve the service performance of the material.

Drawings

Fig. 1 is a microstructure diagram of a high thermal conductivity metal-based carbon fiber heater case.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention provides a preparation method of a high-heat-conductivity metal-based carbon fiber heating element material, which comprises the following steps:

preparing carbon fiber powder with surface activity by a microwave radiation ultrasonic oxidation method;

coating carbide on the surface of the carbon fiber powder by a molten salt method to prepare coated carbon fiber powder;

and pressing the coated carbon fiber powder and the alloy powder into a heating needle shape by a hot pressing method to prepare the heating material.

In one embodiment, the microwave radiation ultrasonic oxidation method specifically comprises: selecting carbon fibers to be invaded into the oxide solution, enabling the carbon fibers to be completely dispersed in the solution, putting the solution into a microwave oven for radiation treatment, simultaneously mixing the solution by using ultrasonic waves, and taking out a sample to be washed to be neutral by deionized water after the ultrasonic oxidation is finished.

In one embodiment, the oxide is at least one of hydrogen peroxide, ozone and potassium permanganate, and the concentration range of the oxide is 2-8%;

and/or the carbon fiber is at least one of chopped PAN series carbon fiber, pitch series carbon fiber and activated carbon fiber, the average diameter of the carbon fiber is 5-15 μm, and the length of the carbon fiber is 0.2-2 mm. The selection of the oxide and the carbon fiber in the above embodiments can be selected by themselves as needed.

In one embodiment, the microwave radiation has a frequency of 1500MHz to 3000MHz and a radiation time of 1s to 1000 s; the ultrasonic frequency range is 10 KHz-50 KHz, and the ultrasonic time is 1 s-1000 s.

In one embodiment, the coating of the carbide on the surface of the carbon fiber powder by a molten salt method specifically includes:

mixing Ti powder and the carbon fiber powder with surface activity to obtain a mixture;

adding molten salt with the same mass into the mixture, and mixing by using a high-energy ball mill, wherein the ball milling medium is absolute ethyl alcohol; and (3) putting the uniformly mixed raw materials into a crucible, introducing argon atmosphere into the crucible, heating the crucible by using microwave, cooling the crucible along with a furnace, and boiling and washing the crucible by using deionized running water to obtain the coated carbon fiber powder.

In one embodiment, the thickness of the carbide layer coated on the surface of the carbon fiber powder is 100nm to 130 nm.

In one embodiment, the molten salt is at least one of NaCl, KCl, NaF, KF, NaBr and KBr, and the average particle size is 1-5 μm;

and/or, the molar ratio of the Ti powder to the carbon fiber powder with surface activity is 1: (4.0-4.2).

Further, the uniformly mixed materials (Ti powder and carbon fiber powder with surface activity)Body, molten salt) was charged into a crucible, and placed in an atmosphere furnace for sintering. The atmosphere is N₂、Ar、CO₂、H₂And the like. The sintering time is 1-5 h, and the sintering temperature is 750-900 ℃. And cleaning the sintered powder by using deionized water to remove molten salt, wherein the cleaning mode is a rotating disc type stirrer, the rotating speed of the rotating disc is 200r/min, and the cleaning time is 1-3h, so that the TiC-coated carbon fiber powder is obtained. In particular to titanium powder with the Ti content of 99-99.99 percent.

In one embodiment, the coated carbon fiber powder is pulverized into carbon fiber powder having an average particle size of 10 to 50 μm, the carbon fiber powder and the alloy powder are mixed, pre-pressed into a shape of a heating pin or a heating rod, and hot-pressed and sintered to obtain a heating material.

In one embodiment, the alloy powder is a mixture of Ti powder and Al powder or a mixture of Cu powder and Mg powder, and the mixing molar ratio is (2.8-3): (0.8 to 1.1),

or the alloy powder is formed by mixing Ti powder, Al powder and Cu powder or Ti powder, Al powder and Mg powder, and the mixing molar ratio is (2.5-3): (0.5-0.8): (0.2-0.4),

and the molar ratio of the alloy powder to the coated carbon fiber powder is 1: (1-2);

and the average grain diameter of the alloy powder is 5-50 μm.

Further, the hot-pressing sintering adopts low-vacuum hot-pressing sintering, the used mold is a graphite mold, the vacuum degree is-0.1 MPa, the pressure range is 15-30 MPa, the temperature range is 800-1300 ℃, the heat preservation time is 1-5 h, the temperature rise rate is 5-20 ℃/min, and the sample is cooled to the room temperature along with the furnace.

The high-heat-conductivity metal-based carbon fiber heating element shell is prepared from any one of the high-heat-conductivity metal-based carbon fiber heating element materials. The heating element shell prepared by using the metal-based carbon fiber material can combine the high heat conduction characteristic of the carbon fiber material and the high strength characteristic of the metal material, improve the heat conduction efficiency of the heating element, reduce the thermal expansion coefficient of the shell and improve the service performance of the material.

The following is a detailed description of the embodiments:

example 1

(1) Surface treatment of carbon fibers

Firstly, completely soaking carbon fibers with the diameter of 10 mu m and the length of 50 mu mPA in an acetone solution, stirring and degumming for 24h, repeatedly washing with deionized water, and then drying in a drying oven at 120 ℃ for 12 h. Preparing a hydrogen peroxide solution with the mass fraction of 5% by using deionized water, then completely immersing degummed carbon fibers into the hydrogen peroxide solution, wherein the using amount of the hydrogen peroxide solution is 30 times of the mass of the carbon fibers, mechanically stirring to completely disperse the carbon fibers in the solution, placing the solution into a microwave heating furnace for radiation treatment for 30s, simultaneously mixing the solution by using ultrasonic waves, taking out a sample after the treatment is finished, washing the sample to be neutral by using the deionized water, and drying the sample at 120 ℃ to constant weight.

(2) Preparation of carbon fiber coating layer

Ti powder having a purity of 99% and a particle diameter of 30 μm and the surface-treated carbon fiber were mixed at a molar ratio of 1: 4. Adding a mixture of NaCl and KCl with the same mass into the mixture, mixing by using a high-energy ball mill according to the mass ratio of 1:1, wherein the ball milling rotation speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the milling ball is zirconia balls. The uniformly mixed raw materials are placed in a crucible, and pure argon (99.9%) is introduced into the crucible. The crucible is heated to 900 ℃ by a microwave heating furnace, and the temperature is kept for 1h, wherein the heating rate is 100 ℃/min. And (4) cooling along with the furnace, repeatedly boiling and washing by using deionized running water, removing salts in the sample, and separating out a carbon fiber sample to obtain the TiC-coated carbon fiber.

(3) Preparation of metal-based carbon fiber composite material

Crushing the obtained carbon fiber into carbon fiber powder with the length of 10 mu m, adding Ti powder, Al powder and Cu powder with the purity of 99 percent according to the molar ratio of 1: 2.5: 0.5: 0.4. and (3) mixing by using a high-energy ball mill, wherein the ball milling rotating speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the grinding balls are zirconia balls. And after the mixing is finished, drying the mixture for 12h at 110 ℃, sieving the mixture by a 50-mesh sieve, filling the obtained powder into a graphite mold, prepressing the powder into a heating needle or heating rod shape at 20MPa, then carrying out heat preservation at the vacuum degree of-0.1 MPa, the pressure of 20MPa, the temperature of 1100 ℃ for 2h, the heating rate of 10 ℃/min, and cooling the sample to the room temperature along with a furnace to obtain the metal-based carbon fiber composite heating needle shell.

Example 2

(1) Surface treatment of carbon fibers

Firstly, completely soaking carbon fibers with the diameter of 10 mu m and the length of 50 mu mPA in an acetone solution, stirring and degumming for 24h, repeatedly washing with deionized water, and then drying in a drying oven at 120 ℃ for 12 h. Preparing a hydrogen peroxide solution with the mass fraction of 5% by using deionized water, then completely immersing degummed carbon fibers into the hydrogen peroxide solution, wherein the using amount of the hydrogen peroxide solution is 30 times of the mass of the carbon fibers, mechanically stirring to completely disperse the carbon fibers in the solution, placing the solution into a microwave heating furnace for radiation treatment for 30s, simultaneously mixing the solution by using ultrasonic waves, taking out a sample after the treatment is finished, washing the sample to be neutral by using the deionized water, and drying the sample at 120 ℃ to constant weight.

(2) Preparation of carbon fiber coating layer

Ti powder having a purity of 99% and a particle diameter of 30 μm and the surface-treated carbon fiber were mixed at a molar ratio of 1: 4. Adding a mixture of NaCl and KCl with the same mass into the mixture, mixing by using a high-energy ball mill according to the mass ratio of 1:1, wherein the ball milling rotation speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the milling ball is zirconia balls. The uniformly mixed raw materials are placed in a crucible, and pure argon (99.9%) is introduced into the crucible. The crucible is heated to 950 ℃ by a microwave heating furnace, and the temperature is kept for 1.5h, wherein the heating rate is 100 ℃/min. And (4) cooling along with the furnace, repeatedly boiling and washing by using deionized running water, removing salts in the sample, and separating out a carbon fiber sample to obtain the TiC-coated carbon fiber.

(3) Preparation of metal-based carbon fiber composite material

The obtained carbon fibers are crushed into carbon fiber powder with the length of 10 mu m, and Ti powder, Al powder, Mg powder and the like with the purity of 99 percent are added according to the molar ratio of 1: 2.6: 0.6: 0.3. and (3) mixing by using a high-energy ball mill, wherein the ball milling rotating speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the grinding balls are zirconia balls. And after the mixing is finished, drying the mixture for 12h at 110 ℃, sieving the mixture by a 50-mesh sieve, filling the obtained powder into a graphite mold, prepressing the powder into a heating needle or heating rod shape at 20MPa, then carrying out heat preservation for 3h at the vacuum degree of-0.1 MPa, the pressure of 20MPa and the temperature of 1000 ℃ at the heating rate of 10 ℃/min, and cooling the sample to the room temperature along with a furnace to obtain the metal-based carbon fiber composite heating needle shell.

Example 3

(1) Surface treatment of carbon fibers

Firstly, completely soaking carbon fibers with the diameter of 10 mu m and the length of 50 mu mPA in an acetone solution, stirring and degumming for 24h, repeatedly washing with deionized water, and then drying in a drying oven at 120 ℃ for 12 h. Preparing a hydrogen peroxide solution with the mass fraction of 8% by using deionized water, then completely immersing degummed carbon fibers into the hydrogen peroxide solution, wherein the using amount of the hydrogen peroxide solution is 30 times of the mass of the carbon fibers, mechanically stirring to completely disperse the carbon fibers in the solution, placing the solution into a microwave heating furnace for radiation treatment for 30s, simultaneously mixing the solution by using ultrasonic waves, taking out a sample after the treatment is finished, washing the sample to be neutral by using the deionized water, and drying the sample at 120 ℃ to constant weight.

(2) Preparation of carbon fiber coating layer

Ti powder having a purity of 99% and a particle diameter of 30 μm and the surface-treated carbon fiber were mixed at a molar ratio of 1: 4. Adding a mixture of NaCl and KCl with the same mass into the mixture, mixing by using a high-energy ball mill according to the mass ratio of 1:1, wherein the ball milling rotation speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the milling ball is zirconia balls. The uniformly mixed raw materials are placed in a crucible, and pure argon (99.9%) is introduced into the crucible. The crucible is heated to 900 ℃ by a microwave heating furnace, and the temperature is kept for 2h, wherein the heating rate is 80 ℃/min. And (4) cooling along with the furnace, repeatedly boiling and washing by using deionized running water, removing salts in the sample, and separating out a carbon fiber sample to obtain the TiC-coated carbon fiber.

(3) Preparation of metal-based carbon fiber composite material

Crushing the obtained carbon fiber into carbon fiber powder with the length of 10 mu m, adding Ti powder, Al powder and Cu powder with the purity of 99 percent according to the molar ratio of 1: 2.5: 0.5: 0.4. and (3) mixing by using a high-energy ball mill, wherein the ball milling rotating speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the grinding balls are zirconia balls. And after the mixing is finished, drying the mixture for 12h at 110 ℃, sieving the mixture by a 50-mesh sieve, filling the obtained powder into a graphite mold, prepressing the powder into a heating needle or heating rod shape at 20MPa, then carrying out heat preservation at the vacuum degree of-0.1 MPa, the pressure of 20MPa, the temperature of 1100 ℃ for 2h, the heating rate of 10 ℃/min, and cooling the sample to the room temperature along with a furnace to obtain the metal-based carbon fiber composite heating needle shell.

Example 4

(1) Surface treatment of carbon fibers

Firstly, completely soaking carbon fibers with the diameter of 10 mu m and the length of 50 mu mPA in an acetone solution, stirring and degumming for 24h, repeatedly washing with deionized water, and then drying in a drying oven at 120 ℃ for 12 h. Preparing a hydrogen peroxide solution with the mass fraction of 8% by using deionized water, then completely immersing degummed carbon fibers into the hydrogen peroxide solution, wherein the using amount of the hydrogen peroxide solution is 30 times of the mass of the carbon fibers, mechanically stirring to completely disperse the carbon fibers in the solution, placing the solution into a microwave heating furnace for radiation treatment for 30s, simultaneously mixing the solution by using ultrasonic waves, taking out a sample after the treatment is finished, washing the sample to be neutral by using the deionized water, and drying the sample at 120 ℃ to constant weight.

(2) Preparation of carbon fiber coating layer

Ti powder having a purity of 99% and a particle diameter of 30 μm and the surface-treated carbon fiber were mixed at a molar ratio of 1: 4. And adding a mixture of NaCl and KF with the same mass into the mixture, and mixing by using a high-energy ball mill according to the mass ratio of 1:1, wherein the ball milling rotation speed is 300r/min, the ball milling time is 2h, the ball milling medium is absolute ethyl alcohol, and the milling ball is zirconia balls. The uniformly mixed raw materials are placed in a crucible, and pure argon (99.9%) is introduced into the crucible. The crucible is heated to 950 ℃ by a microwave heating furnace, and the temperature is kept for 1.5h, wherein the heating rate is 100 ℃/min. And (4) cooling along with the furnace, repeatedly boiling and washing by using deionized running water, removing salts in the sample, and separating out a carbon fiber sample to obtain the TiC-coated carbon fiber.

(3) Preparation of metal-based carbon fiber composite material

The obtained carbon fibers are crushed into carbon fiber powder with the length of 10 mu m, and Ti powder, Al powder, Mg powder and the like with the purity of 99 percent are added according to the molar ratio of 1: 2.6: 0.6: 0.3. and (3) mixing by using a high-energy ball mill, wherein the ball milling rotating speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the grinding balls are zirconia balls. And after the mixing is finished, drying the mixture for 12h at 110 ℃, sieving the mixture by a 50-mesh sieve, filling the obtained powder into a graphite mold, prepressing the powder into a heating needle or heating rod shape at 20MPa, then carrying out heat preservation for 3h at the vacuum degree of-0.1 MPa, the pressure of 20MPa and the temperature of 1000 ℃ at the heating rate of 10 ℃/min, and cooling the sample to the room temperature along with a furnace to obtain the metal-based carbon fiber composite heating needle shell.

Example 5

(1) Surface treatment of carbon fibers

Firstly, completely soaking carbon fibers with the diameter of 10 mu m and the length of 50 mu mPA in an acetone solution, stirring and degumming for 24h, repeatedly washing with deionized water, and then drying in a drying oven at 120 ℃ for 12 h. Preparing a hydrogen peroxide solution with the mass fraction of 10% by using deionized water, then completely immersing degummed carbon fibers into the hydrogen peroxide solution, wherein the using amount of the hydrogen peroxide solution is 30 times of the mass of the carbon fibers, mechanically stirring to completely disperse the carbon fibers in the solution, placing the solution into a microwave heating furnace for radiation treatment for 30s, simultaneously mixing the solution by using ultrasonic waves, taking out a sample after the treatment is finished, washing the sample to be neutral by using the deionized water, and drying the sample at 120 ℃ to constant weight.

(2) Preparation of carbon fiber coating layer

Ti powder having a purity of 99% and a particle diameter of 30 μm and the surface-treated carbon fiber were mixed at a molar ratio of 1: 4. Adding a mixture of NaCl and KCl with the same mass into the mixture, mixing by using a high-energy ball mill according to the mass ratio of 1:1, wherein the ball milling rotation speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the milling ball is zirconia balls. The uniformly mixed raw materials are placed in a crucible, and pure argon (99.9%) is introduced into the crucible. The crucible is heated to 850 ℃ by using a microwave heating furnace, and the temperature is kept for 5h, wherein the heating rate is 100 ℃/min. And (4) cooling along with the furnace, repeatedly boiling and washing by using deionized running water, removing salts in the sample, and separating out a carbon fiber sample to obtain the TiC-coated carbon fiber.

(3) Preparation of metal-based carbon fiber composite material

Crushing the obtained carbon fibers into carbon fiber powder with the length of 10 mu m, adding Ti powder, Al powder and Mg powder with the purity of 99 percent according to the molar ratio of 1: 2.5: 0.5: 0.3. and (3) mixing by using a high-energy ball mill, wherein the ball milling rotating speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the grinding balls are zirconia balls. And after the mixing is finished, drying the mixture for 12h at 110 ℃, sieving the mixture by a 50-mesh sieve, filling the obtained powder into a graphite mold, prepressing the powder into a heating needle or heating rod shape at 20MPa, then carrying out heat preservation at the vacuum degree of-0.1 MPa, the pressure of 20MPa, the temperature of 1100 ℃ for 2h, the heating rate of 10 ℃/min, and cooling the sample to the room temperature along with a furnace to obtain the metal-based carbon fiber composite heating needle shell.

Example 6

(1) Surface treatment of carbon fibers

Firstly, completely soaking carbon fibers with the diameter of 10 mu m and the length of 50 mu mPA in an acetone solution, stirring and degumming for 24h, repeatedly washing with deionized water, and then drying in a drying oven at 120 ℃ for 12 h. Preparing a hydrogen peroxide solution with the mass fraction of 10% by using deionized water, then completely immersing degummed carbon fibers into the hydrogen peroxide solution, wherein the using amount of the hydrogen peroxide solution is 30 times of the mass of the carbon fibers, mechanically stirring to completely disperse the carbon fibers in the solution, placing the solution into a microwave heating furnace for radiation treatment for 60s, simultaneously mixing the solution by using ultrasonic waves, taking out a sample after the treatment is finished, washing the sample to be neutral by using the deionized water, and drying the sample at 120 ℃ to constant weight.

(2) Preparation of carbon fiber coating layer

Ti powder having a purity of 99% and a particle diameter of 30 μm and the surface-treated carbon fiber were mixed at a molar ratio of 1: 4. Adding a mixture of NaCl and KCl with the same mass into the mixture, mixing by using a high-energy ball mill according to the mass ratio of 1:1, wherein the ball milling rotation speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the milling ball is zirconia balls. The uniformly mixed raw materials are placed in a crucible, and pure argon (99.9%) is introduced into the crucible. The crucible is heated to 950 ℃ by a microwave heating furnace, and the temperature is kept for 1.5h, wherein the heating rate is 100 ℃/min. And (4) cooling along with the furnace, repeatedly boiling and washing by using deionized running water, removing salts in the sample, and separating out a carbon fiber sample to obtain the TiC-coated carbon fiber.

(3) Preparation of metal-based carbon fiber composite material

The obtained carbon fibers are crushed into carbon fiber powder with the length of 10 mu m, and Ti powder, Al powder, Mg powder and the like with the purity of 99 percent are added according to the molar ratio of 1: 2.6: 0.6: 0.3. and (3) mixing by using a high-energy ball mill, wherein the ball milling rotating speed is 300r/min, the ball milling time is 2 hours, the ball milling medium is absolute ethyl alcohol, and the grinding balls are zirconia balls. And after the mixing is finished, drying the mixture for 12h at 110 ℃, sieving the mixture by a 50-mesh sieve, filling the obtained powder into a graphite mold, prepressing the powder into a heating needle or heating rod shape at 20MPa, then carrying out heat preservation for 3h at the vacuum degree of-0.1 MPa, the pressure of 20MPa and the temperature of 1000 ℃ at the heating rate of 10 ℃/min, and cooling the sample to the room temperature along with a furnace to obtain the metal-based carbon fiber composite heating needle shell.

Case(s)	Coefficient of thermal expansion (. degree. C. -1)	Thermal conductivity W/(m.K)
			Example 1	7×10-6	320
Example 2	8×10-6	300
			Example 3	9×10-6	338
Example 4	8.5×10-6	330
			Example 5	7.3×10-6	325
Example 6	9.2×10-6	340

Among the above-described measurement parameters, the thermal expansion coefficient was measured using a thermal expansion tester DH4608A metal thermal expansion tester, and the thermal conductivity was measured using a DRM-1 flat thermal conductivity meter, using a thermal conductivity meter.

Based on the measurement data, the heating element material prepared by the method has good heat conduction efficiency and effective thermal expansion coefficient, and can be applied to the preparation of a heating element shell, so that the product performance can be obviously improved.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.