Carbon fiber / ceramic material containing a helical structure and method for producing the same

Abstract

The present application relates to a kind of carbon fiber / ceramic material containing helical structure and its preparation method.The method: carbon fiber bundle is carried out on polytetrafluoroethylene film and is spread yarn, and carbon fiber weftless cloth is obtained;Ceramic slurry is brushed on the surface of carbon fiber weftless cloth, then polytetrafluoroethylene film is covered;The obtained sandwich structure is immersed in liquid nitrogen to remove polytetrafluoroethylene film, and ceramic film is obtained;Multiple ceramic films are sequentially horizontally stacked in clockwise or counterclockwise direction according to preset angle, so that the included angle between the carbon fiber bundle of adjacent ceramic films is preset angle;The obtained green body preform is molded and cured in vacuum environment;The obtained ceramic green body is pyrolyzed and densified by PIP process, and carbon fiber / ceramic material containing helical structure is prepared.The fracture toughness and fracture work of the carbon fiber / ceramic material prepared by the present application are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon fiber toughened ceramic materials, and relates to a carbon fiber / ceramic material containing a spiral structure and a preparation method thereof. BACKGROUND

[0002] Ultra-high temperature ceramics have good oxidation resistance and ablation resistance, high melting point, high strength, high temperature resistance and chemical inertness, and other excellent properties. However, the inherent brittleness, crack sensitivity and low toughness of ceramic materials seriously affect the application of ceramic materials in many advanced fields. At present, the toughening methods of ultra-high temperature ceramics are mainly divided into two categories: structural toughening and adding phase toughening. In the existing application of ultra-high temperature ceramics, multiple toughening methods are usually applied to a composite material to improve the inherent brittleness and low toughness of the ultra-high temperature ceramic material.

[0003] There are related reports on the preparation of carbon fiber ceramic matrix composites containing spiral structure (Bouligand structure) in the prior art. For example, Chinese Patent Application CN110845240A discloses a preparation method for realizing spiral microstructure carbon fiber toughened ceramic material by vacuum filtration and spark plasma sintering technology. For example, Chinese Patent Application CN115124360A discloses a preparation method for realizing carbon fiber toughened ceramic material with biomimetic spiral and brick-mud layered structure by precursor impregnation and hot-pressing sintering technology. However, the materials prepared by the above two methods have the problem of poor mechanical properties, and the bonding ability between the upper and lower carbon fiber composite layers is weak. In addition, the hot-pressing sintering technology and the spark plasma sintering technology involved in the above two methods need to force the combination of each layer by high pressure and high temperature. This sintering process needs to apply a considerable pressure, and sintering under high pressure conditions will limit the shape of the green body, which may cause deformation of the material shape, and is not suitable for the preparation of materials with protrusions or other special shapes.

[0004] In summary, it is necessary to provide a new carbon fiber / ceramic material containing a spiral structure and a preparation method thereof. SUMMARY

[0005] In order to solve one or more technical problems in the prior art, the present application provides a carbon fiber / ceramic material containing a spiral structure and a preparation method thereof.

[0006] In a first aspect, the present application provides a preparation method of a carbon fiber / ceramic material containing a spiral structure, which comprises the following steps:

[0007] (1) Spreading the carbon fiber bundle on a polytetrafluoroethylene film to obtain a carbon fiber veil on the polytetrafluoroethylene film;

[0008] (2) brushing the surface of the carbon fiber veil obtained on the polytetrafluoroethylene film with ceramic slurry, then covering the polytetrafluoroethylene film to obtain a sandwich structure;

[0009] (3) soaking the sandwich structure in liquid nitrogen to remove the polytetrafluoroethylene film to obtain a ceramic film;

[0010] (4) sequentially horizontally stacking a plurality of ceramic films in a clockwise or counterclockwise direction at a preset angle, so that the included angle between the carbon fiber bundles of adjacent ceramic films is the preset angle, to obtain a green body preform containing a spiral structure;

[0011] (5) mold curing the green body preform containing the spiral structure in a vacuum environment to obtain a ceramic green body;

[0012] (6) high-temperature pyrolysis and PIP process densification of the ceramic green body to obtain a carbon fiber / ceramic material containing a spiral structure.

[0013] Preferably, the soaking time in liquid nitrogen is not more than 2 min.

[0014] Preferably, the mold curing is performed in a mold die, the mold die comprising a mold body and an inner liner located in the mold body, the inner liner comprising a gasket for clamping the green body preform therein, the inner liner being in clearance fit with the gasket; the gasket comprises an upper gasket and a lower gasket, and the mold curing is performed by clamping the upper gasket and the lower gasket and curing at 120-200°C for 1-2 h.

[0015] Preferably, the absolute pressure of the vacuum environment is not more than 10 -3 Pa; the high-temperature pyrolysis is atmospheric pressure pyrolysis at a temperature of 1000-1200°C for 0.5-1.5 h; the high-temperature pyrolysis is performed under the protection of a flowing inert gas, and the flow rate of the inert gas during the high-temperature pyrolysis is 5-10 L / h; and / or the PIP process uses polycarbosilane as the impregnating liquid, and the number of repetitions of the PIP process is 6-10 times, preferably 8 times.

[0016] Preferably, the ceramic slurry is prepared by uniformly mixing a ceramic precursor, zirconium diboride powder and silicon carbide powder to obtain the ceramic slurry.

[0017] Preferably, the mass ratio of the zirconium diboride powder, the silicon carbide powder and the ceramic precursor is (14-16):(1.5-2.5):(4-6), preferably 15:2:5; and / or the ceramic precursor is polycarbosilane.

[0018] Preferably, the carbon fiber bundle in step (1) is a pretreated carbon fiber bundle, the pretreatment of the carbon fiber bundle is: soaking the carbon fiber bundle with N-methyl pyrrolidone, then washing with anhydrous ethanol, repeating the soaking and washing in turn for multiple times, and finally drying to obtain the pretreated carbon fiber bundle; the width of the single carbon fiber after spreading is not less than 1.5 cm; the length of the carbon fiber veil obtained on the polytetrafluoroethylene film is 9-10 cm, and the width is not less than 4.4 cm; preferably, when the length of the carbon fiber veil obtained on the polytetrafluoroethylene film is 9 cm and the width is 4.5 cm, the mass of the ceramic slurry for brushing is 0.715 g.

[0019] Preferably, before step (3) is performed, a step of uniformly scraping the obtained sandwich structure with a scraper is further included; and / or the range interval of the preset angle is (0°, 90°], preferably 10-30°.

[0020] Preferably, the carbon fiber / ceramic material containing a spiral structure prepared has a bending strength of 240-390 MPa, a fracture toughness of 7-12 MPa·m 1 / 2 , and a fracture work of 1300-2300 J / m 2 .

[0021] The present application provides, in a second aspect, a carbon fiber / ceramic material containing a spiral structure prepared by the preparation method described in the first aspect of the present application.

[0022] Compared with the prior art, the present application has at least the following beneficial effects:

[0023] (1) The present application is based on the microstructure Bouligand structure (biomimetic spiral structure) in marine crustacean biological materials, and for the first time combines a mold forming process and an ultralow-temperature demolding technology to realize the biomimetic Bouligand microstructure in a ceramic matrix composite material, and at the same time realizes the preparation of an ultrathin ceramic film, which can contain more spiral periods in a limited height; at present, there is no report on the preparation of a carbon fiber toughened ceramic composite material containing a spiral structure (Bouligand structure) by using a mold forming process and an ultralow-temperature demolding technology in combination with a ceramic precursor impregnation and pyrolysis process, the present application realizes the construction of a Bouligand structure in a ceramic matrix composite material, and in combination with an ultralow-temperature demolding technology, realizes the preparation of a ceramic film, which can contain more complete periods in a unit thickness (unit size), and the present application can prepare 6-8 or even more complete periods in 2 mm.

[0024] (2) The Bouligand structure is introduced in the continuous carbon fiber toughened ceramic matrix composite material, the thickness of single layer can be effectively controlled in the preparation process of the ceramic film, and the preparation of the ultra-thin ceramic layer is realized; in the research on the Bouligand structure composite material, most of the research is based on the carbon fiber toughened resin matrix composite material, and in the research on the ceramic matrix composite material, due to the great difficulty in preparation, only a limited number of layers can be researched, while the Bouligand microstructure is constructed in the ceramic matrix composite material, and the preparation effect of the complete period and multiple periods is realized; more importantly, the low-temperature demolding technology is combined, so that the fusion and bonding force of the upper and lower ceramic slurries in the preparation process are stronger, so that better mechanical properties are realized; the mechanical properties of the carbon fiber / ceramic material containing the spiral structure prepared by the present application are obviously better than those of the prior art, the fracture toughness can reach about 1.3-3 times of the existing carbon fiber toughened ceramic matrix composite material containing the spiral structure, and the fracture function can reach more than 1.4-1.7 times of the existing carbon fiber toughened ceramic matrix composite material containing the spiral structure. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a preparation flowchart of the carbon fiber / ceramic material containing the spiral structure in some specific embodiments of the present application;

[0026] Figure 2 is a schematic diagram of the spiral structure arrangement of the present application;

[0027] Figure 3 is a microstructure diagram of the fracture SEM scanning of the period 6 sample of the carbon fiber / ceramic material containing the spiral structure prepared in embodiment 1 of the present application;

[0028] Figure 4 is a single-edge notched beam force and displacement curve diagram of the period 6 sample of the carbon fiber / ceramic material containing the spiral structure prepared in embodiment 1 of the present application;

[0029] Figure 5 is a microstructure diagram of the fracture SEM scanning of the period 8 sample of the carbon fiber / ceramic material containing the spiral structure prepared in embodiment 1 of the present application;

[0030] Figure 6 is a schematic diagram of the cross-sectional structure of the mold pressing mold used in some specific embodiments of the present application; in the figure, 1 is a mold pressing mold, 2 is an inner liner, 3 is a gasket, and 4 is a blank preform;

[0031] Figure 7 is a schematic diagram of the outer contour of the mold pressing mold used in some specific embodiments of the present application. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] The present application provides in a first aspect a method for preparing a carbon fiber / ceramic material having a spiral structure, the method comprising the following steps:

[0034] (1) spreading a carbon fiber bundle on a polytetrafluoroethylene film to obtain a carbon fiber veil on the polytetrafluoroethylene film; in the present application, preferably, the carbon fiber bundle is a pretreated carbon fiber bundle, the pretreatment of the carbon fiber bundle is: soaking the carbon fiber bundle with N-methyl pyrrolidone, then washing with anhydrous ethanol, repeating the soaking and washing in turn for multiple times, and finally drying to obtain the pretreated carbon fiber bundle; specifically, for example, after soaking the carbon fiber bundle with N-methyl pyrrolidone (NMP) organic solvent for 48-96 hours, preferably 72 hours, pouring out the NMP solution, placing the fiber in anhydrous ethanol for ultrasonic cleaning, for example, ultrasonic cleaning for 10 minutes, then pouring out the anhydrous ethanol, repeating the above soaking and cleaning operation for three times, and placing in a drying oven for drying to obtain the pretreated carbon fiber bundle; in order to ensure that the fiber bundle does not disperse when the carbon fiber is delivered from the factory, a certain amount of resin is generally added to constrain the fiber bundle, the present application soaks the carbon fiber bundle with an organic solvent, which can make the resin dissolve in the NMP organic solvent; the process conditions for spreading are not specifically limited in the present application, which are the conventional technology in the art; specifically, step (1) is for example spreading the pretreated carbon fiber bundle on the polytetrafluoroethylene film to a certain width (spreading to a preset width) to obtain the carbon fiber veil;

[0035] (2) the surface of the carbon fiber unidirectional fabric obtained in step (1) is brushed with ceramic slurry, and then a polytetrafluoroethylene film is covered to obtain a sandwich structure; the polytetrafluoroethylene film is not specifically limited in the present application, and can be a product purchased directly or a product prepared by an existing method; in the present application, for example, steps (1) and (2) are repeated multiple times to obtain a large number of sandwich structures; in the present application, for example, the ceramic slurry is brushed on the carbon fiber unidirectional fabric in a weight-controlled manner, and then the polytetrafluoroethylene film is covered, preferably a mold knife is used to cut out a preset shape, for example, a sandwich structure disc is obtained; in the present application, the ceramic slurry is prepared, for example: a ceramic precursor (PCS) is mixed with a certain amount of ZrB2 (zirconium diboride) powder and SiC (silicon carbide) powder, mixed and stirred for more than 24 h to obtain a uniform ceramic slurry; in the present application, preferably, before step (3) is performed, a step of uniformly scraping the sandwich structure with a scraper is performed, preferably, the scraper is repeatedly scraped along the fiber arrangement direction of the carbon fiber bundle, and the number of times of scraping can be, for example, 4-12 times; in the present application, due to the sandwiching of the ceramic film between the two layers of polytetrafluoroethylene film, the scraper can be used for uniform scraping, which helps the ceramic slurry to be more uniformly coated on the carbon fiber unidirectional fabric, so that a ceramic film layer with consistency can be formed on the entire surface, avoiding the problems of uneven thickness or local excessive coating, and also helping to avoid the possible phenomena of bubbles, impurities or unevenness during coating, obviously improving the quality and performance of the ceramic film layer;

[0036] (3) the sandwich structure is soaked in liquid nitrogen to remove the polytetrafluoroethylene film, and a ceramic film (also referred to as a carbon fiber ceramic composite film) is obtained; in the present application, when the polytetrafluoroethylene film sandwiched with the ceramic film is soaked in liquid nitrogen, the polytetrafluoroethylene film will quickly shrink and separate due to the difference in shrinkage rate, and a ceramic film with a certain hardness in a frozen state at low temperature is obtained;

[0037] (4) a plurality of ceramic films are sequentially and horizontally stacked (horizontal stacking) in a clockwise or counterclockwise direction at a preset angle, so that the included angle between the carbon fiber bundles of adjacent ceramic films is the preset angle, and a green body preform containing a spiral structure is obtained; wherein the orientation of the carbon fiber bundles in the green body preform is distributed in a clockwise or counterclockwise direction; the unidirectional Bouligand structure is arranged in the same spiral direction with a certain angle difference, such as Figure 2As shown, according to a certain direction, spiral arrangement, horizontal layer arrangement; specifically, for example, the obtained ceramic film is placed in the mold in a certain angle, forming a spiral arrangement of the layer structure with a certain angle difference, and the fiber bundle of each ceramic film is in a fixed angle with the fiber bundle of the previous ceramic film in clockwise or counterclockwise direction, so that the fiber bundle in each ceramic film is in a spiral shape as a whole;

[0038] (5) The green body preform containing the spiral structure is subjected to mold curing in a vacuum environment to obtain a ceramic green body; in the mold curing process, after complete mold closing, there are still a small amount of bubbles in the green body preform, which reduces the amount of exuded slurry; the mold curing is performed in a vacuum environment, which is different from the conventional cross-linking curing in an air atmosphere, and is helpful to remove the bubbles from the green body containing the spiral structure, reduces the residual bubbles in the green body, and thus reduces the formation of pores and other defects, and is helpful to form a more dense structure, thereby improving the density and strength of the ceramic green body;

[0039] (6) The ceramic green body is subjected to high-temperature pyrolysis and PIP process densification to obtain a carbon fiber / ceramic material containing a spiral structure; in the present application, for example, the ceramic green body is placed in a tube furnace and subjected to high-temperature pyrolysis in a flowing protective gas environment, and then subjected to PIP process to improve the density of the material, thereby obtaining a carbon fiber / ceramic material containing a spiral structure (Bouligande structure); the carbon fiber / ceramic material containing a spiral structure in the present application is a continuous carbon fiber toughened ceramic matrix composite material containing a Bouligand structure.

[0040] The present application can improve the coating effect of the subsequent ceramic slurry, can make the ceramic slurry fully adhere to the surface of the carbon fiber, and can make the ceramic slurry on the carbon fiber non-woven fabric more uniform, and another piece of polytetrafluoroethylene film is covered on the carbon fiber non-woven fabric coated with ceramic slurry, which forms a sandwich structure, and the ceramic film is sandwiched between the two polytetrafluoroethylene films. In addition to facilitating subsequent liquid nitrogen treatment, it can also facilitate uniform treatment by a scraper, which can make the ceramic slurry on the carbon fiber non-woven fabric more uniform. The polytetrafluoroethylene film sandwich structure with the ceramic film is soaked in liquid nitrogen, which not only removes the polytetrafluoroethylene film, but more importantly makes the ceramic film temporarily frozen. Since the ceramic slurry on the ceramic film is not solidified but only temporarily frozen, the fusion and bonding force of the upper and lower ceramic slurries can be significantly improved in the subsequent step, thereby greatly improving the mechanical properties of the material. If the ceramic layer is first crosslinked and solidified, the ceramic slurry attached to the carbon fiber non-woven fabric has already solidified, which will result in weak bonding between the upper and lower carbon fiber composite layers. Of course, there are also reports of ceramic slurry on carbon fiber non-woven fabric obtained by vacuum filtration in the prior art. However, due to problems such as uniformity of the concentration, viscosity or flowability of the ceramic slurry, or due to the fact that the surface of the carbon fiber non-woven fabric is not flat enough during the vacuum filtration process, the ceramic slurry may not be evenly distributed on the fabric surface, which will affect the quality and performance of the ceramic film. In addition, the ceramic film obtained by vacuum filtration may contain impurities or bubbles due to the problems in the vacuum filtration process, which will affect the performance of the carbon fiber / ceramic material.

[0041] In order to improve the fiber wettability, the present application needs to spread a single fiber bundle to a certain width, and after brushing the ceramic slurry, the whole presents a soft state. The present application adopts a low-temperature demolding technology, which not only can make the ceramic film maintain relative integrity during the transfer and lamination process, but more importantly, compared with the ceramic layer which is first solidified and then laminated, the ceramic film obtained by the present application can make the fusion and bonding force of the upper and lower ceramic slurries stronger, thereby greatly improving the mechanical properties of the material. The present application first combines the molding process of resin composite materials and the precursor impregnation process to realize the preparation of continuous carbon fiber toughened ceramic matrix composite materials containing Bouligande structure (biological spiral structure). It realizes better control of the fiber volume fraction and prepares ceramic green bodies with stable fiber volume fraction. In addition, the present application adopts a low-temperature demolding (liquid nitrogen demolding) technology to realize the preparation of ceramic film with controllable thickness.

[0042] There is no report on the preparation of carbon fiber toughened ceramic composite material containing spiral structure (Bouligand structure) by using the molding process and ultra-low temperature demolding technology combined with the ceramic precursor impregnation pyrolysis process. The present application realizes the construction of Bouligand structure in the ceramic matrix composite, and realizes the preparation of ultra-thin ceramic film by combining the ultra-low temperature demolding technology, which can contain more complete cycles in unit thickness (unit size). The present application can prepare 6-8 or even more complete cycles in 2mm. The mechanical properties of the carbon fiber / ceramic material containing spiral structure prepared by the present application are significantly better than those of the prior art. The fracture toughness can reach 1.3-3 times of the existing carbon fiber toughened ceramic matrix composite containing spiral structure, and the fracture function can reach more than 1.4-1.7 times of the existing carbon fiber toughened ceramic matrix composite containing spiral structure.

[0043] According to some preferred embodiments, the soaking time in liquid nitrogen is not more than 2min, for example 1-2min. In the present application, the direct soaking method using liquid nitrogen can quickly freeze and realize rapid demolding.

[0044] According to some preferred embodiments, the molding curing is carried out in a molding mold, for example, as shown in Figure 6 and Figure 7 The molding mold 1 includes a mold body and an inner liner 2 located in the mold body, and the inner liner 2 includes a gasket 3 for clamping a green body preform 4, and the inner liner and the gasket are in clearance fit. The gasket includes an upper gasket and a lower gasket, and the molding curing is to clamp the upper gasket and the lower gasket, and to cure at 120-200℃ (for example 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃ or 200℃) for 1-2h (for example 1h, 1.5h or 2h). In the present application, the molding mold is bolted, and the inner liner and the gasket are in clearance fit, which facilitates exhaust in a vacuum environment and facilitates the flow of excess slurry along the gap during the molding process. In the present application, different sizes of gaskets are added according to the size of the clamped green body preform, and only the clamping of the upper gasket and the lower gasket can realize the control of the overall size of the clamped green body preform.

[0045] According to some preferred embodiments, the absolute pressure of the vacuum environment is not more than 10 -3Pa; the high-temperature pyrolysis is atmospheric pyrolysis at 1000-1200℃ (e.g. 1000℃, 1050℃, 1100℃, 1150℃ or 1200℃) for 0.5-1.5h (e.g. 0.5, 1 or 1.5h); unlike the hot-press sintering and spark plasma sintering techniques in the prior art, which both need to force the combination of each layer by high pressure and high temperature, the shape of the green body is limited, the present application is suitable for irregular materials by high-temperature atmospheric pyrolysis and PIP process, after the ceramic green body with different shapes is prepared by moulding, high-temperature atmospheric pyrolysis and repeated PIP process densification are carried out, which will not be limited by the size and shape.

[0046] According to some preferred embodiments, the high-temperature pyrolysis is carried out under the protection of flowing inert gas, and the flow rate of the inert gas is 5-10L / h (e.g. 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10L / h) when the high-temperature pyrolysis is carried out; the present application preferably carries out the high-temperature pyrolysis under the protection of flowing inert gas, and it is found that the flow of inert gas helps to form a more dense ceramic structure during high-temperature pyrolysis, reduces the formation of pores and defects, and thus improves the density and compactness of the ceramic green body, which may be because the flow of inert gas helps to remove the gas generated by the pyrolysis of PCS, reduces the formation of pores and defects, and also prevents air from entering and being oxidized by high temperature; in the present application, the flow rate of the inert gas is preferably controlled to be 5-10L / h, and insufficient gas flow rate will result in that the inert gas cannot effectively cover the surface of the ceramic green body, thus failing to provide sufficient protection, while too high a flow rate of gas flow may generate too much gas flow pressure on the surface of the ceramic green body, thus leading to unstable gas flow dynamics on the surface.

[0047] According to some preferred embodiments, the PIP process uses polycarbosilane as the impregnation liquid, and the PIP process is repeated for 6-10 times, preferably 8 times; in the present application, the polycarbosilane (PCS) is a liquid polycarbosilane, which is a precursor of SiC, and is provided by the Institute of Chemistry, Chinese Academy of Sciences, and is a flowable liquid at room temperature, and is a light yellow transparent liquid, and can be cross-linked and solidified at 120-200℃, and is a colorless transparent crystal after solidification, and is cracked into SiC bulk at high temperature; in the present application, the PIP process using liquid polycarbosilane as the impregnation liquid is a conventional technique in the art, and the PIP process (polymer impregnation pyrolysis process) is, for example, vacuum impregnation of liquid polycarbosilane into a ceramic green body, followed by solidification and high-temperature cracking, and the steps are, for example, vacuum impregnation of the ceramic green body after high-temperature cracking, followed by solidification, and high-temperature cracking after the completion of solidification, and the temperature of vacuum impregnation is, for example, 20-30℃, and the time of vacuum impregnation is, for example, 1-3h, and the temperature of solidification is, for example, 120-200℃, and the time of solidification is, for example, 1-5h, and the temperature of high-temperature cracking is, for example, 1000-1200℃, and the time of high-temperature cracking is, for example, 1-2h, and the high-temperature cracking is performed in a flowable protective gas.

[0048] According to some preferred embodiments, the ceramic slurry is prepared by uniformly mixing a ceramic precursor, zirconium diboride powder and silicon carbide powder.

[0049] According to some preferred embodiments, the mass ratio of the zirconium diboride powder, the silicon carbide powder and the ceramic precursor is (14-16):(1.5-2.5):(4-6), preferably 15:2:5; in the present application, the zirconium diboride powder is, for example, a powder with a particle size of 50nm-5μm, the silicon carbide powder is, for example, a powder with a particle size of 0.2-1μm, and / or the ceramic precursor is polycarbosilane (liquid polycarbosilane).

[0050] According to some preferred embodiments, the carbon fiber bundle in step (1) is a pretreated carbon fiber bundle, and the pretreatment of the carbon fiber bundle is soaking the carbon fiber bundle in N-methyl pyrrolidone, and then washing with anhydrous ethanol, and repeating the soaking and washing in turn for multiple times, and finally drying to obtain the pretreated carbon fiber bundle; the width of the single carbon fiber bundle after being spread is not less than 1.5cm; the length of the carbon fiber veil obtained on the polytetrafluoroethylene film is 9-10cm, and the width is not less than 4.4cm; preferably, when the length of the carbon fiber veil obtained on the polytetrafluoroethylene film is 9cm, and the width is 4.5cm, the mass of the ceramic slurry for brushing is 0.715g.

[0051] According to some preferred embodiments, before step (3) is performed, a step of using a doctor blade to scrape the obtained sandwich structure is further included; and / or the preset angle is in the range interval of (0°, 90°], preferably 10-30°.

[0052] According to some preferred embodiments, the carbon fiber / ceramic material containing a spiral structure prepared has a bending strength of 240-390 MPa, preferably not less than 350 MPa, a fracture toughness of 7-12 MPa·m 1 / 2 , preferably not less than 10 MPa·m 1 / 2 , a fracture work of 1300-2300 J / m 2 , preferably not less than 2000 J / m 2 .

[0053] The present application provides, in a second aspect, a carbon fiber / ceramic material containing a spiral structure prepared by the preparation method described in the first aspect of the present application.

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present application. In the absence of a specific description, each reaction raw material used in the embodiments and comparative examples of the present application can be commercially purchased or synthesized by existing methods.

[0055] Embodiment 1

[0056] ①After soaking the carbon fiber bundle in N-methyl pyrrolidone (NMP) organic solvent for 72 h, the NMP solution was poured out, and then the carbon fiber bundle was ultrasonically cleaned in anhydrous ethanol for 10 min. The anhydrous ethanol was then poured out, and the above soaking and cleaning operations were repeated three times. The pretreated carbon fiber bundle was then dried in a drying oven, and then spread on a polytetrafluoroethylene film to obtain a carbon fiber veil on the polytetrafluoroethylene film. The spreading method of the carbon fiber bundle was as follows: 3 bundles of pretreated 12K carbon fibers with a length of 9 cm were taken and separated, and the carbon fiber filaments were uniformly arranged in the same direction. The 3 bundles of carbon fibers were spread to form a carbon fiber veil with a size of 9 cm (length) x 4.5 cm (width), and the single bundle of carbon fibers was spread to a width of 1.5 cm.

[0057] ②obtaining the carbon fiber veil on a polytetrafluoroethylene film, then covering the polytetrafluoroethylene film to obtain a sandwich structure, and then using a doctor blade to uniformly scrape the sandwich structure, that is, repeatedly scraping the sandwich structure along the fiber arrangement direction of the carbon fiber bundle for 8 times, and cutting to obtain a sandwich structure disc (diameter 40 mm); the mass of the ceramic slurry brushed on a 9 cm (length) x 4.5 cm (width) carbon fiber veil is 0.715 g; the ceramic slurry is prepared as follows: ZrB2 powder and SiC powder are added to liquid polycarbosilane, mixed and stirred for 24 h to obtain a uniform ceramic slurry, wherein the mass ratio of ZrB2 powder, SiC powder and liquid polycarbosilane is 15:2:5; repeating steps ① and ② multiple times to obtain a large number of sandwich structure discs (diameter 40 mm).

[0058] ③immersing the obtained sandwich structure disc in liquid nitrogen for 1 min to remove the polytetrafluoroethylene film to obtain a ceramic film.

[0059] ④sequentially horizontally stacking a plurality of ceramic films according to an interlayer spiral angle (i.e. a preset angle) of 30° in a clockwise direction to arrange a spiral layered structure to obtain a green body preform containing a spiral structure; wherein the included angle between the fiber bundles of adjacent ceramic films is 30°, and the obtained green body preform containing a spiral structure has 6 complete spiral periods within 2 mm.

[0060] ⑤molding and curing the green body preform containing a spiral structure in a vacuum environment (the absolute pressure of the vacuum environment is not more than 10 -3 Pa) to obtain a ceramic body; the molding and curing is carried out in a molding die, the molding die comprises a die body and an inner liner located in the die body, the inner liner comprises a gasket for clamping the green body preform, and the inner liner and the gasket are in clearance fit; the gasket comprises an upper gasket and a lower gasket, and the molding and curing is as follows: the upper gasket and the lower gasket are tightly combined, and cured at 160℃ for 1 h.

[0061] ⑥The ceramic green body is pyrolyzed at high temperature and densified by PIP process to obtain carbon fiber / ceramic material containing spiral structure; the pyrolysis at high temperature is pyrolysis at 1200℃ for 1h under normal pressure, and the pyrolysis at high temperature is carried out under the protection of flowing argon gas, and the flow rate of argon gas is 8L / h during the pyrolysis at high temperature; the PIP process uses liquid polycarbosilane as impregnating liquid, and the PIP process is repeated for 8 times; each PIP process includes the following steps: vacuum impregnation of the ceramic green body after pyrolysis at high temperature, the temperature of vacuum impregnation is 25℃, the time of vacuum impregnation is 2h, then solidification, the temperature of solidification is 160℃, the time of solidification is 2h, after the solidification is completed, pyrolysis at high temperature (pyrolysis at high temperature under normal pressure) is carried out, the temperature of pyrolysis at high temperature is 1200℃, the time of pyrolysis at high temperature is 1h, and the pyrolysis at high temperature is carried out in flowing argon atmosphere, and the flow rate of argon is 8L / h.

[0062] Example 2

[0063] Example 2 is basically the same as Example 1, except that:

[0064] ①The carbon fiber bundle is soaked in N-methyl pyrrolidone (NMP) organic solvent for 72h, then the NMP solution is poured out, and then the carbon fiber bundle is placed in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then the anhydrous ethanol is poured out, and the above soaking and cleaning operation is repeated three times, and then the carbon fiber bundle is placed in a drying oven for drying to obtain a pretreated carbon fiber bundle, then the pretreated carbon fiber bundle is spread on a polytetrafluoroethylene film to obtain a carbon fiber veil on the polytetrafluoroethylene film; the spreading method of the carbon fiber bundle is as follows: 2 bundles of pretreated 12K carbon fibers with a length of 9cm are taken, and the carbon fibers are separated to make the carbon fiber filaments uniformly arranged in the same direction, and the 2 bundles of carbon fibers are spread to form a carbon fiber veil with a size of 9cm (length) x 4.4cm (width), and the single bundle of carbon fibers is spread to a width of 2.2cm.

[0065] ②The surface of the carbon fiber veil obtained on the polytetrafluoroethylene film is brushed with ceramic slurry, then the polytetrafluoroethylene film is covered to obtain a sandwich structure, then the sandwich structure is uniformly scraped by a scraper, that is, the scraper is repeatedly scraped along the fiber arrangement direction of the carbon fiber bundle for 8 times, and a sandwich structure disc (diameter 40mm) is obtained by cutting; the mass of the ceramic slurry brushed on a 9cm (length) x 4.4cm (width) carbon fiber veil is 0.478g; the preparation of the ceramic slurry is as follows: ZrB2 powder and SiC powder are added into liquid polycarbosilane, mixed and stirred for 24h to obtain a uniform ceramic slurry, and the mass ratio of ZrB2 powder, SiC powder and liquid polycarbosilane is 15:2:5; steps ① and ② are repeated multiple times to obtain a large amount of sandwich structure discs.

[0066] (4) sequentially horizontally stack the plurality of ceramic films according to the interlayer spiral angle (i.e. preset angle) 30° in a clockwise direction to form a spiral layered structure, to obtain a green body preform containing a spiral structure; wherein the included angle between the fiber bundles of adjacent ceramic films is 30°, and the obtained green body preform containing a spiral structure has 8 complete spiral periods within 2 mm.

[0067] Comparative Example 1

[0068] Comparative Example 1 is basically the same as Example 1, except that:

[0069] (5) the green body preform containing a spiral structure is subjected to mold curing in an air atmosphere to obtain a ceramic green body; the mold curing is performed in a mold, and the mold includes a mold body and an inner liner in the mold body, and the inner liner includes a gasket for clamping the green body preform, and the inner liner and the gasket are in clearance fit; the gasket includes an upper gasket and a lower gasket, and the mold curing is performed by clamping the upper gasket and the lower gasket and curing at 160°C for 1 h.

[0070] The amount of slurry precipitated during mold curing and the quality of the ceramic green body obtained by mold curing in this comparative example are obviously not as good as the results of mold curing in a vacuum environment in Example 1.

[0071] Comparative Example 2

[0072] (1) carbon fiber bundles were soaked in N-methyl pyrrolidone (NMP) organic solvent for 72 h, then the NMP solution was poured out, and the carbon fiber bundles were then placed in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then the anhydrous ethanol was poured out, and the above soaking and cleaning operations were repeated three times, and the carbon fiber bundles were then placed in a drying oven for drying, to obtain pretreated carbon fiber bundles, which were then spread to obtain carbon fiber veil; the spreading method of the carbon fiber bundles was as follows: 3 bundles of pretreated 12K carbon fibers with a length of 9 cm were taken and separated, and the carbon fiber filaments were uniformly arranged in the same direction, and the 3 bundles of carbon fibers were spread to form a carbon fiber veil with a size of 9 cm (length) x 4.5 cm (width), and each bundle of carbon fibers was spread to a width of 1.5 cm.

[0073] ② brushing ceramic slurry on the surface of the carbon fiber unidirectional fabric, then standing for 10 h at 25℃ to make the ceramic slurry fully enter and wrap the carbon fiber, then curing at 160℃ for 1 h to make it crosslink and solidify, to obtain ceramic film, and cutting into ceramic film disc; the mass of ceramic slurry brushed on a 9 cm (length) x 4.5 cm (width) carbon fiber unidirectional fabric is 0.715 g; the preparation of the ceramic slurry is: adding ZrB2 powder and SiC powder into liquid polycarbosilane, mixing and stirring for 24 h to obtain uniform ceramic slurry, wherein the mass ratio of ZrB2 powder, SiC powder and liquid polycarbosilane is 15:2:5; repeating steps ① and ② multiple times to obtain a large number of ceramic film discs (diameter 40 mm).

[0074] ③ stacking multiple ceramic film discs in a clockwise direction according to the interlayer spiral angle (i.e. the preset angle) 30° to sequentially arrange them into a spiral layered structure to obtain a green body preform containing a spiral structure; wherein the included angle between the fiber bundles of adjacent ceramic films is 30°, and the obtained green body preform containing a spiral structure has 6 complete spiral periods within 2 mm.

[0075] ④ molding the green body preform containing a spiral structure in a vacuum environment (the absolute pressure of the vacuum environment is not more than 10 -3 Pa) to obtain a ceramic green body; the molding is performed in a molding die, and the molding die comprises a die body and an inner liner located in the die body, and the inner liner comprises a gasket for clamping the green body preform, and the inner liner and the gasket are in clearance fit; the gasket comprises an upper gasket and a lower gasket, and the molding is performed by clamping the upper gasket and the lower gasket at 160℃ for 1 h.

[0076] ⑤ pyrolysis and PIP densification of the ceramic green body to obtain a carbon fiber / ceramic material containing a spiral structure; the pyrolysis is performed at a temperature of 1200℃ under normal pressure for 1 h, and the pyrolysis is performed under the protection of flowing argon gas, and the flow rate of argon gas is 8 L / h during pyrolysis; the PIP process uses liquid polycarbosilane as the impregnating liquid, and the number of repetitions of the PIP process is 8; each PIP step: vacuum impregnation of the ceramic green body after pyrolysis at a temperature of 25℃ for 2 h, followed by curing at a temperature of 160℃ for 2 h, and then pyrolysis (pyrolysis under normal pressure) at a temperature of 1200℃ for 1 h, and the pyrolysis is performed in a flowing argon atmosphere, and the flow rate of argon is 8 L / h.

[0077] The flowability of the ceramic film is provided by the PCS, which has certain viscosity at room temperature. In the comparative example, the ceramic slurry no longer has flowability after being cured at 160 DEG C, the surface is dry, and no longer has viscosity. The comparative example has the problem that it cannot be bonded at room temperature and normal pressure, and cannot form a complete green body.

[0078] Comparative Example 3

[0079] Comparative Example 3 is basically the same as Comparative Example 2, except that:

[0080] 2) The first ceramic slurry is brushed on the surface of the carbon fiber veil cloth, and then is allowed to stand at 25 DEG C for 10 h, so that the ceramic slurry fully enters and wraps the carbon fiber, and then is allowed to stand in an oven at 160 DEG C for 1 h to crosslink and cure, to obtain a ceramic layer, and is cut into a ceramic layer disc (40 mm in diameter); then the ceramic layer is hung with the second ceramic slurry, and then is allowed to stand at 50 DEG C for 30 min to completely dry, to obtain a ceramic film disc, wherein the mass of the ceramic film disc is increased by 0.05 g compared to the mass of the ceramic layer disc; the mass of the first ceramic slurry brushed on one carbon fiber veil cloth of 9 cm (length) x 4.5 cm (width) is 0.715 g; the first ceramic slurry is prepared by adding ZrB2 powder and SiC powder into liquid polycarbosilane, mixing and stirring for 24 h, to obtain a uniform first ceramic slurry, wherein the mass ratio of ZrB2 powder, SiC powder and liquid polycarbosilane is 15:2:5; the second ceramic slurry is prepared by dispersing a solid phase component composed of zirconium diboride powder and silicon carbide powder in anhydrous ethanol, and mixing to obtain the second ceramic slurry; wherein the volume fraction ratio of zirconium diboride powder and silicon carbide powder is 4:1, and the volume ratio of anhydrous ethanol to the solid phase component is 5:1; steps 1) and 2) are repeated multiple times to obtain a large number of ceramic film discs (40 mm in diameter).

[0081] The comparative example applies the hanging slurry treatment method compared to Comparative Example 2, but still cannot improve the adhesion between the ceramic films of the layers, and the upper and lower layers cannot be effectively bonded by mold pressing, and at the same time, because new ceramic powder is added between the layers, it is difficult to control the height of the green body under low pressure, which ultimately affects the volume fraction of the carbon fiber in the green body.

[0082] Comparative Examples 2 and 3 both have the problem that it is difficult to effectively bond the upper and lower layers together at 1200 DEG C under normal pressure.

[0083] The room temperature (25 DEG C) fracture toughness, bending strength and fracture work of the materials finally prepared in Examples 1-2 and Comparative Example 1 are tested, and the results are shown in Table 1.

[0084] Table 1

[0085]

[0086] The part of the present application not described in detail is the technology known to the person skilled in the art.

[0087] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing a carbon fiber / ceramic material having a spiral structure, characterized by, The method comprises the following steps: (1) spreading carbon fiber bundles on a polytetrafluoroethylene film to obtain carbon fiber veil on the polytetrafluoroethylene film; (2) brushing ceramic slurry on the surface of the carbon fiber veil obtained on the polytetrafluoroethylene film, then covering the polytetrafluoroethylene film to obtain a sandwich structure; (3) soaking the sandwich structure in liquid nitrogen to remove the polytetrafluoroethylene film to obtain a ceramic film; (4) sequentially horizontally stacking a plurality of ceramic films according to a preset angle in a clockwise or counterclockwise direction, so that the included angle between the carbon fiber bundles of adjacent ceramic films is the preset angle, to obtain a green body preform containing a spiral structure; (5) mold curing the green body preform containing the spiral structure in a vacuum environment to obtain a ceramic green body; (6) high-temperature pyrolysis and PIP process densification of the ceramic green body to obtain a carbon fiber / ceramic material containing a spiral structure.

2. The preparation method according to claim 1, wherein the soaking time in liquid nitrogen is not more than 2 min.

3. The preparation method according to claim 1, wherein the mold curing is performed in a mold die, and the mold die comprises a die body and an inner liner in the die body, and the inner liner comprises a gasket for clamping the green body preform, and the inner liner and the gasket are in clearance fit; the gasket comprises an upper gasket and a lower gasket, and the mold curing is performed by clamping the upper gasket and the lower gasket and curing at 120-200°C for 1-2 h.

4. The preparation method according to claim 1, wherein the high-temperature pyrolysis is performed at a temperature of 1000-1200°C under normal pressure for 0.5-1.5 h; the high-temperature pyrolysis is performed under the protection of flowing inert gas, and the flow rate of the inert gas is 5-10 L / h during the high-temperature pyrolysis; and / or the PIP process uses polycarbosilane as the impregnating liquid, and the number of repetitions of the PIP process is 6-10 times. The absolute pressure of the vacuum environment is not greater than 10 -3 Pa; 5. The preparation method according to claim 4, wherein the number of repetitions of the PIP process is 8 times.

6. The preparation method according to claim 1, wherein the ceramic slurry is prepared by uniformly mixing a ceramic precursor, zirconium diboride powder and silicon carbide powder.

7. The preparation method according to claim 6, wherein the mass ratio of the zirconium diboride powder, the silicon carbide powder and the ceramic precursor is (14-16):(1.5-2.5):(4-6); and / or the ceramic precursor is polycarbosilane.

8. The preparation method according to claim 7, wherein the mass ratio of the zirconium diboride powder, the silicon carbide powder and the ceramic precursor is 15:2:

5.

9. The preparation method according to claim 1, wherein the carbon fiber bundles in step (1) are pretreated carbon fiber bundles, and the pretreatment of the carbon fiber bundles comprises soaking the carbon fiber bundles in N-methylpyrrolidone, then washing with anhydrous ethanol, repeatedly performing the soaking and washing, and finally drying to obtain the pretreated carbon fiber bundles. ​ ​ ​ ​ ​ ​ ​ ​ ​ The width of the single carbon fiber after spreading is not less than 1.5 cm; The length of the carbon fiber veil obtained on the polytetrafluoroethylene film is 9-10 cm, and the width is not less than 4.4 cm.

10. The preparation method according to claim 9, characterized in that: When the length of the carbon fiber veil obtained on the polytetrafluoroethylene film is 9 cm, and the width is 4.5 cm, the mass of the ceramic slurry for brushing is 0.715 g.

11. The preparation method according to claim 1, characterized in that: Before step (3) is performed, the method further comprises a step of uniformly scraping the obtained sandwich structure by using a scraper; and / or The range interval of the preset angle is (0°, 90°].

12. The preparation method according to claim 11, characterized in that: The range interval of the preset angle is 10-30 °C.

13. The preparation method according to any one of claims 1-12, characterized in that: The bending strength of the carbon fiber / ceramic material with the spiral structure is 240-390 MPa, the fracture toughness is 7-12 MPa·m 1 / 2 , and the fracture work is 1300-2300 J / m 2 .

14. A carbon fiber / ceramic material containing a spiral structure prepared by the preparation method according to any one of claims 1-13.

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