阅读说明：本技术 氧化铝纤维增强碳化硅陶瓷材料的制备方法及制得的氧化铝纤维增强碳化硅陶瓷材料 (Preparation method of alumina fiber reinforced silicon carbide ceramic material and prepared alumina fiber reinforced silicon carbide ceramic material ) 是由 吴宝林 侯振华 吴迪 于 2021-10-08 设计创作，主要内容包括：本发明提供氧化铝纤维增强碳化硅陶瓷材料的制备方法,包括以下步骤：改性氧化铝纤维布的制备、改性氧化铝纤维布层的制备、压制、烧结、增强、表面清理。本发明还提供了氧化铝纤维增强碳化硅陶瓷材料,包括：分散有棒状氧化铝和/或片状氧化铝的碳化硅材料,碳化硅材料内设置的多层改性氧化铝纤维布层,碳化硅材料表面的碳化硅增强层；所述改性氧化铝纤维布包括表面分散磷酸氢锆的氧化铝纤维布。该碳化硅陶瓷材料内部设有改性氧化铝纤维布层,同时在纤维布层上沉积磷酸氢锆氧化铝纤维布层与碳化硅的接触面积大大提高,不仅提高了材料强度,而且提高了材料韧性,同时在碳化硅内掺杂棒状和/或片状氧化铝,从而大大提高了碳化硅陶瓷材料的韧性。(The invention provides a preparation method of an alumina fiber reinforced silicon carbide ceramic material, which comprises the following steps: the preparation method comprises the steps of preparation of modified alumina fiber cloth, preparation of the modified alumina fiber cloth layer, pressing, sintering, reinforcement and surface cleaning. The invention also provides an alumina fiber reinforced silicon carbide ceramic material, comprising: the silicon carbide material is dispersed with rod-shaped alumina and/or flake alumina, a plurality of layers of modified alumina fiber cloth layers are arranged in the silicon carbide material, and a silicon carbide enhancement layer is arranged on the surface of the silicon carbide material; the modified alumina fiber cloth comprises alumina fiber cloth with zirconium hydrogen phosphate dispersed on the surface. The modified alumina fiber cloth layer is arranged in the silicon carbide ceramic material, the contact area between the zirconium hydrogen phosphate alumina fiber cloth layer deposited on the fiber cloth layer and the silicon carbide is greatly increased, the material strength is improved, the material toughness is improved, and simultaneously rodlike and/or flaky alumina is doped in the silicon carbide, so that the toughness of the silicon carbide ceramic material is greatly improved.)

1. The preparation method of the alumina fiber reinforced silicon carbide ceramic material is characterized by comprising the following steps: the method comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

(2) preparing a modified alumina fiber cloth layer: adding rod-shaped alumina and/or flake alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; uniformly spraying partial silicon carbide slurry on the surface of the modified alumina fiber cloth, laminating the modified alumina fiber cloth sprayed with slurry in multiple layers, and needling by using a needle with barbs to obtain the modified alumina fiber cloth layer;

(3) pressing: adding a sintering aid into the balance of the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould after drying, and pressurizing to perform compression molding to obtain a silicon carbide ceramic biscuit;

(4) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material;

(5) enhancing: placing the silicon carbide ceramic material in the step (4) in a reaction kettle, introducing inert gas, pressurizing to 2-3MPa, heating to 1500-fold sand 1600 ℃ at the speed of 5-10 ℃/min, preserving heat for 2-4h, cooling to 600-fold sand 850 ℃ along with a furnace, and preserving heat for 1-2 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of the polycarbosilane in the reaction kettle reaches 0.05-0.5mol/L, heating to 1200-1400 ℃ at the speed of 5-10 ℃/min and preserving heat for 4-8 h; then stopping introducing polycarbosilane, keeping the flow of the inert gas at 100-;

(6) surface cleaning: and taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

2. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (1), ethylene diamine tetraacetic acid is also contained in the zirconium hydrogen phosphate dispersion, and the pH value is adjusted to 3-4; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g (100-300) mL; the airing conditions are as follows: standing at room temperature for 10-15 h or keeping the temperature at 50-70 ℃ for 1-2 h.

3. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (2), the length-diameter ratio of the rod-shaped alumina is 3 to 5, and the radial width of the rod-shaped alumina is 0.1 to 0.8 μm; the width of the plate of the flaky alumina is 0.3-6.0 mu m, and the ratio of the width of the plate to the thickness of the plate is 3-10.

4. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (2), the weight ratio of the rod-shaped alumina and/or the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is (4-6): 20: (1-4): (1-4); the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethylcellulose or tetramethylammonium hydroxide, and the weight of the dispersing agent is 0.5-0.7% of the total weight of the rodlike alumina and/or the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the thickness of the laminated modified alumina fiber cloth layer of the multilayer spraying slurry is 1-3 mm.

5. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (3), the weight of the sintering aid is 2-4% of the total weight of the rodlike alumina and/or the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 1-2 h; the pressing pressure is 150-²The pressing time is 1-10 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: (40-80).

6. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (4), the sintering temperature is 2100-2200 ℃, and the sintering time is 1-3 h.

7. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (5), the preparation method of the polycarbosilane comprises the following steps:

(a) uniformly dispersing nano boehmite in an aqueous solution of KH550, and ultrasonically oscillating for 0.5-2 hours to obtain a mixture 1;

(b) distilling polydimethylsiloxane PDMS, collecting the fraction at 103 ℃, and drying; and then dropwise adding an organic solvent into the mixture and continuously stirring until the mass ratio of the organic solvent to the polydimethylsiloxane PDMS is (5-15): 100, denoted as solution 2;

(c) pouring the mixture 1 into the solution 2, heating in water bath at 60-80 ℃, and stirring for 2-6 hours to obtain a mixture 3;

(d) putting the mixture 3 into a reaction kettle, introducing mixed gas of CO2 and inert gas, and pressurizing to 5-10 MPa; heating to 500-520 ℃ according to a certain heating program, and preserving heat for 12-24 hours; cooling to room temperature along with the furnace to obtain a crude product 4;

(e) and dissolving the crude product 4 in an organic solvent, filtering, vacuumizing, and distilling under reduced pressure to obtain the polycarbosilane PCS.

8. The method for preparing an alumina fiber reinforced silicon carbide ceramic material according to claim 1, wherein: in the step (6), the surface cleaning method comprises the following steps: firstly, polishing the surface by using sand paper, then placing the polished surface in ethanol for cleaning, and then placing the cleaned surface at 60-80 ℃ for drying.

9. An alumina fibre reinforced silicon carbide ceramic material obtainable by the process of any one of claims 1 to 8.

10. An alumina fiber reinforced silicon carbide ceramic material, comprising: the silicon carbide material is dispersed with rod-shaped alumina and/or flake alumina, a plurality of layers of modified alumina fiber cloth layers are arranged in the silicon carbide material, and a silicon carbide enhancement layer is arranged on the surface of the silicon carbide material; the modified alumina fiber cloth comprises alumina fiber cloth with zirconium hydrogen phosphate dispersed on the surface.

Technical Field

The invention belongs to the field of new materials, and particularly relates to an alumina fiber reinforced silicon carbide ceramic material and a preparation method thereof.

Background

Silicon carbide is used as an important structural ceramic material, and by virtue of excellent high-temperature mechanical strength, high hardness, high elastic modulus, high wear resistance, high thermal conductivity, corrosion resistance and other properties, the silicon carbide is not only applied to the traditional industrial fields of high-temperature kiln furniture, combustion nozzles, heat exchangers, sealing rings, sliding bearings and the like, but also can be used as a bulletproof armor material, a space reflector, a clamp material in semiconductor wafer preparation and a nuclear fuel cladding material.

Silicon carbide materials have properties such as high hardness, wear resistance, and high elastic modulus, which are largely determined by their high covalent bonding and stable crystal structure. The silicon carbide has two crystal structures of beta and alpha, beta-SiC is a face-centered cubic sphalerite structure, and alpha-SiC is a hexagonal wurtzite structure. The alpha-SiC derives 2H, 4H, 6H, 15R and other polytypes due to different stacking modes of the structural unit layers, wherein the 6H polytype is the most widely applied in industry. Although SiC exists in many polytypes and has varying lattice constants, its densities are very close. The density of the beta-SiC is 3.215g/cm³The densities of the various alpha-SiC variants were essentially the same, 3.217g/cm³. beta-SiC, commonly referred to as "low temperature modification", is a metastable phase at room temperature that converts to one or more polytypes of alpha-SiC at temperatures above 2100 ℃ and the conversion is irreversible. The 15R variant is thermodynamically less stable, is the mesophase generated when the β -SiC → 6H-SiC conversion occurs, and is absent at high temperatures. In addition, SiC synthesized at 2000 ℃ or lower in the production of silicon carbide powder is mainly β -type, while SiC synthesized at 2200 ℃ or higher is mainly α -SiC and mainly 6H.

Ceramic materials have many advantages not comparable to other materials, but their brittleness is an inevitable fatal disadvantage, and the brittleness of ceramic materials greatly affects the reliability and consistency of material properties. Ceramic materials are polycrystalline structures consisting of ionic or covalent bonds and lack a slip system which promotes the deformation of the material, which, once subjected to an applied load, together with the presence of micro-defects on the surface of the material, which are difficult to avoid by ceramic processes, may constitute sources of cracks at which stresses are concentrated at the tips of these cracks, and in which there are no other systems which consume external energy, exchanged only by new free energy, which is the energy absorbed by the new surface formed by the propagation of the crack tip, with the result that the crack rapidly propagates and is manifested as a so-called brittle fracture. It follows that the brittleness of a ceramic material is determined by the chemical bonding properties of the substance and its microstructure. Therefore, in order to make silicon carbide exhibit its excellent wear resistance, its brittleness, i.e., toughness of the silicon carbide ceramic, should be overcome first.

In order to improve the toughness of silicon carbide ceramics, a great deal of scientific research is carried out, and from the viewpoint of the formation mode of a toughened microstructure, the silicon carbide ceramics can be divided into two types: (1) the self-toughening silicon carbide ceramic is prepared by sintering or heat treatment to generate toughening phase in microstructure; (2) the toughening of additive is to add a second phase with toughening effect by a mechanical mixing method, wherein the most applications are fiber toughening, particle toughening, phase change toughening and the like.

Although multiple toughening materials have been developed, the toughening effect has various problems and is difficult to satisfy.

Disclosure of Invention

The technical problem is as follows: in order to overcome the defects of the prior art, the invention provides a preparation method of an alumina fiber reinforced silicon carbide ceramic material and the prepared alumina fiber reinforced silicon carbide ceramic material.

The technical scheme is as follows: the invention provides a preparation method of an alumina fiber reinforced silicon carbide ceramic material, which comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

(2) preparing a modified alumina fiber cloth layer: adding rod-shaped alumina and/or flake alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; uniformly spraying partial silicon carbide slurry on the surface of the modified alumina fiber cloth, laminating the modified alumina fiber cloth sprayed with slurry in multiple layers, and needling by using a needle with barbs to obtain the modified alumina fiber cloth layer;

(3) pressing: adding a sintering aid into the balance of the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould after drying, and pressurizing to perform compression molding to obtain a silicon carbide ceramic biscuit;

(4) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material;

(5) enhancing: placing the silicon carbide ceramic material in the step (4) in a reaction kettle, introducing inert gas, pressurizing to 2-3MPa, heating to 1500-fold sand 1600 ℃ at the speed of 5-10 ℃/min, preserving heat for 2-4h, cooling to 600-fold sand 850 ℃ along with a furnace, and preserving heat for 1-2 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of the polycarbosilane in the reaction kettle reaches 0.05-0.5mol/L, heating to 1200-1400 ℃ at the speed of 5-10 ℃/min and preserving heat for 4-8 h; then stopping introducing polycarbosilane, keeping the flow of the inert gas at 100-;

(6) and taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

In the step (1), ethylene diamine tetraacetic acid is also contained in the zirconium hydrogen phosphate dispersion, and the pH value is adjusted to 3-4; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g (100-300) mL; the airing conditions are as follows: standing at room temperature for 10-15 h or keeping the temperature at 50-70 ℃ for 1-2 h.

In the step (2), the length-diameter ratio of the rod-shaped alumina is 3 to 5, and the radial width of the rod-shaped alumina is 0.1 to 0.8 μm; the width of the plate of the flaky alumina is 0.3-6.0 mu m, and the ratio of the width of the plate to the thickness of the plate is 3-10.

In the step (2), the weight ratio of the rod-shaped alumina and/or the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is (4-6): 20: (1-4): (1-4); the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethylcellulose or tetramethylammonium hydroxide, and the weight of the dispersing agent is 0.5-0.7% of the total weight of the rodlike alumina and/or the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the thickness of the laminated modified alumina fiber cloth layer of the multilayer spraying slurry is 1-3 mm.

In the step (3), the weight of the sintering aid is 2-4% of the total weight of the rodlike alumina and/or the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 1-2 h; the pressing pressure is 150-²The pressing time is 1-10 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: (40-80).

In the step (4), the sintering temperature is 2100-2200 ℃, and the sintering time is 1-3 h.

In the step (5), the preparation method of the polycarbosilane comprises the following steps:

(a) uniformly dispersing nano boehmite in an aqueous solution of KH550, and ultrasonically oscillating for 0.5-2 hours to obtain a mixture 1;

(b) distilling polydimethylsiloxane PDMS, collecting the fraction at 103 ℃, and drying; and then dropwise adding an organic solvent into the mixture and continuously stirring until the mass ratio of the organic solvent to the polydimethylsiloxane PDMS is (5-15): 100, denoted as solution 2;

(c) pouring the mixture 1 into the solution 2, heating in water bath at 60-80 ℃, and stirring for 2-6 hours to obtain a mixture 3;

(d) putting the mixture 3 into a reaction kettle, introducing mixed gas of CO2 and inert gas, and pressurizing to 5-10 MPa; heating to 500-520 ℃ according to a certain heating program, and preserving heat for 12-24 hours; cooling to room temperature along with the furnace to obtain a crude product 4;

(e) and dissolving the crude product 4 in an organic solvent, filtering, vacuumizing, and distilling under reduced pressure to obtain the polycarbosilane PCS.

In the step (6), the surface cleaning method comprises the following steps: firstly, polishing the surface by using sand paper, then placing the polished surface in ethanol for cleaning, and then placing the cleaned surface at 60-80 ℃ for drying.

The invention also provides the alumina fiber reinforced silicon carbide ceramic material prepared by the method.

The invention also provides an alumina fiber reinforced silicon carbide ceramic material, which comprises: the silicon carbide material is dispersed with rod-shaped alumina and/or flake alumina, a plurality of layers of modified alumina fiber cloth layers are arranged in the silicon carbide material, and a silicon carbide enhancement layer is arranged on the surface of the silicon carbide material; the modified alumina fiber cloth comprises alumina fiber cloth with zirconium hydrogen phosphate dispersed on the surface.

Has the advantages that: the modified alumina fiber cloth layer is arranged in the silicon carbide ceramic material, meanwhile, the contact area between the zirconium hydrogen phosphate alumina fiber cloth layer deposited on the fiber cloth layer and the silicon carbide is greatly increased, the material strength is improved, the material toughness is improved, and simultaneously, rod-shaped and/or sheet-shaped alumina is doped in the silicon carbide, so that the toughness of the silicon carbide ceramic material is greatly improved.

Detailed Description

The present invention is further explained below.

In the present invention, the rod-shaped alumina used has an aspect ratio of 3 to 5 and a radial width of 0.1 to 0.8. mu.m; the plate width of the flaky alumina is 0.3-6.0 mu m, and the ratio of the plate width to the plate thickness is 3-10.

Example 1

The preparation method of the alumina fiber reinforced silicon carbide ceramic material comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

the zirconium hydrogen phosphate dispersion also comprises ethylene diamine tetraacetic acid, and the pH value is adjusted to 3.5; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g:200 mL; the airing conditions are as follows: keeping the temperature for 1.5h at 50-70 ℃.

(2) Preparing a modified alumina fiber cloth layer: adding rod-shaped alumina and flake-shaped alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; uniformly spraying partial silicon carbide slurry on the surface of the modified alumina fiber cloth, laminating the modified alumina fiber cloth sprayed with slurry in multiple layers, and needling by using a needle with barbs to obtain the modified alumina fiber cloth layer;

the weight ratio of the rod-shaped alumina to the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is 5: 20: 2.5: 2.5, the weight ratio of the rod-shaped alumina to the flake-shaped alumina is 1: 2; the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethyl cellulose or tetramethyl ammonium hydroxide, and the weight of the dispersing agent is 0.6 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the thickness of the laminated modified alumina fiber cloth layer of the multilayer spraying slurry is 2 mm.

(3) Pressing: adding a sintering aid into the balance of the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould after drying, and pressurizing to perform compression molding to obtain a silicon carbide ceramic biscuit;

the weight of the sintering aid is 3 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 1.5 h; the pressing pressure is 200MPa/cm²The pressing time is 5 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: 60.

(4) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2150 ℃, and the sintering time is 2 h.

(5) Enhancing: putting the silicon carbide ceramic material obtained in the step (4) into a reaction kettle, introducing inert gas, pressurizing to 2.5MPa, heating to 1550 ℃ at the speed of 8 ℃/min, preserving heat for 3h, furnace-cooling to 750 ℃ and preserving heat for 1.5 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of polycarbosilane in the reaction kettle reaches 0.3mol/L, heating to 1300 ℃ at the speed of 8 ℃/min and preserving heat for 6 hours; then stopping introducing polycarbosilane, keeping the flow of the inert gas at 150ml/min, and cooling to room temperature along with the furnace;

the preparation method of the polycarbosilane comprises the following steps:

(a) uniformly dispersing nano boehmite in an aqueous solution of KH550, and ultrasonically oscillating for 1 hour to obtain a mixture 1;

(b) distilling polydimethylsiloxane PDMS, collecting the fraction at 103 ℃, and drying; and then dropwise adding an organic solvent into the mixture and continuously stirring the mixture until the mass ratio of the organic solvent to the polydimethylsiloxane PDMS is 10: 100, denoted as solution 2;

(c) pouring the mixture 1 into the solution 2, heating in a water bath at 70 ℃, and stirring for 4 hours to obtain a mixture 3;

(d) putting the mixture 3 into a reaction kettle, introducing mixed gas of CO2 and inert gas, and pressurizing to 8 MPa; heating to 510 ℃ according to a certain heating program, and preserving heat for 18 hours; cooling to room temperature along with the furnace to obtain a crude product 4;

(e) and dissolving the crude product 4 in an organic solvent, filtering, vacuumizing, and distilling under reduced pressure to obtain the polycarbosilane PCS.

(6) And taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

The surface cleaning method comprises the following steps: firstly, the surface is polished by sand paper, then the surface is cleaned in ethanol, and finally the surface is dried at 70 ℃.

Example 2

The preparation method of the alumina fiber reinforced silicon carbide ceramic material comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

the zirconium hydrogen phosphate dispersion also comprises ethylene diamine tetraacetic acid, and the pH value is adjusted to 4; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g:300 mL; the airing conditions are as follows: keeping the temperature at 50 ℃ for 2 h.

(2) Preparing a modified alumina fiber cloth layer: adding rod-shaped alumina and flake-shaped alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; uniformly spraying partial silicon carbide slurry on the surface of the modified alumina fiber cloth, laminating the modified alumina fiber cloth sprayed with slurry in multiple layers, and needling by using a needle with barbs to obtain the modified alumina fiber cloth layer;

the weight ratio of the rod-shaped alumina to the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is 6: 20: 1: 4, the weight ratio of the rod-shaped alumina to the flake-shaped alumina is 1: 1; the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethyl cellulose or tetramethyl ammonium hydroxide, and the weight of the dispersing agent is 0.5 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the thickness of the laminated modified alumina fiber cloth layer of the multilayer spraying slurry is 1 mm.

(3) Pressing: adding a sintering aid into the balance of the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould after drying, and pressurizing to perform compression molding to obtain a silicon carbide ceramic biscuit;

the weight of the sintering aid is 2 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 2 h; the pressing pressure is 150MPa/cm²The pressing time is 10 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: 40.

(4) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2100 ℃, and the sintering time is 1 h.

(5) Enhancing: putting the silicon carbide ceramic material obtained in the step (4) into a reaction kettle, introducing inert gas, pressurizing to 2MPa, heating to 1500 ℃ at the speed of 10 ℃/min, preserving heat for 4h, cooling to 600 ℃ along with a furnace, and preserving heat for 2 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of the polycarbosilane in the reaction kettle reaches 0.05mol/L, heating to 1200 ℃ at the speed of 10 ℃/min and preserving heat for 8 hours; stopping introducing polycarbosilane, keeping the flow of inert gas at 100ml/min, and cooling to room temperature along with the furnace;

the preparation method of the polycarbosilane comprises the following steps:

(a) uniformly dispersing nano boehmite in an aqueous solution of KH550, and ultrasonically oscillating for 2 hours to obtain a mixture 1;

(b) distilling polydimethylsiloxane PDMS, collecting the fraction at 103 ℃, and drying; and then dropwise adding an organic solvent into the mixture and continuously stirring the mixture until the mass ratio of the organic solvent to the polydimethylsiloxane PDMS is 15: 100, denoted as solution 2;

(c) pouring the mixture 1 into the solution 2, heating in water bath at 60 ℃, and stirring for 6 hours to obtain a mixture 3;

(d) putting the mixture 3 into a reaction kettle, introducing mixed gas of CO2 and inert gas, and pressurizing to 5 MPa; heating to 520 ℃ according to a certain heating program, and keeping the temperature for 24 hours; cooling to room temperature along with the furnace to obtain a crude product 4;

(e) and dissolving the crude product 4 in an organic solvent, filtering, vacuumizing, and distilling under reduced pressure to obtain the polycarbosilane PCS.

(6) And taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

The surface cleaning method comprises the following steps: firstly, polishing the surface by using sand paper, then placing the polished surface in ethanol for cleaning, and then placing the cleaned surface at 80 ℃ for drying.

Example 3

The preparation method of the alumina fiber reinforced silicon carbide ceramic material comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

the zirconium hydrogen phosphate dispersion also comprises ethylene diamine tetraacetic acid, and the pH value is adjusted to 3; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g:100 mL; the airing conditions are as follows: keeping the temperature at 70 ℃ for 1 h.

(2) Preparing a modified alumina fiber cloth layer: adding rod-shaped alumina and flake-shaped alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; uniformly spraying partial silicon carbide slurry on the surface of the modified alumina fiber cloth, laminating the modified alumina fiber cloth sprayed with slurry in multiple layers, and needling by using a needle with barbs to obtain the modified alumina fiber cloth layer;

the weight ratio of the rod-shaped alumina to the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is 4: 20: 4: 1, the weight ratio of the rod-shaped alumina to the flake alumina is 1: 3; the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethyl cellulose or tetramethyl ammonium hydroxide, and the weight of the dispersing agent is 0.7 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the thickness of the laminated modified alumina fiber cloth layer of the multilayer spraying slurry is 3 mm.

(3) Pressing: adding a sintering aid into the balance of the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould after drying, and pressurizing to perform compression molding to obtain a silicon carbide ceramic biscuit;

the weight of the sintering aid is 4% of the total weight of the rodlike aluminum oxide, the flaky aluminum oxide, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 1 h; the pressing pressure is 250MPa/cm²The pressing time is 1 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: 80.

(4) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2200 ℃ and the sintering time is 3 h.

(5) Enhancing: putting the silicon carbide ceramic material in the step (4) into a reaction kettle, introducing inert gas, pressurizing to 3MPa, heating to 1600 ℃ at the speed of 5 ℃/min, preserving heat for 2h, furnace-cooling to 850 ℃ and preserving heat for 1 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of the polycarbosilane in the reaction kettle reaches 0.5mol/L, heating to 1400 ℃ at the speed of 5 ℃/min and preserving heat for 4 hours; then stopping introducing polycarbosilane, keeping the flow of inert gas at 200ml/min, and cooling to room temperature along with the furnace;

the preparation method of the polycarbosilane comprises the following steps:

(a) uniformly dispersing nano boehmite in an aqueous solution of KH550, and ultrasonically oscillating for 0.5 hour to obtain a mixture 1;

(b) distilling polydimethylsiloxane PDMS, collecting the fraction at 103 ℃, and drying; and then dropwise adding an organic solvent into the mixture and continuously stirring the mixture until the mass ratio of the organic solvent to the polydimethylsiloxane PDMS is 5: 100, denoted as solution 2;

(c) pouring the mixture 1 into the solution 2, heating in water bath at 80 ℃, and stirring for 2 hours to obtain a mixture 3;

(d) putting the mixture 3 into a reaction kettle, introducing mixed gas of CO2 and inert gas, and pressurizing to 10 MPa; heating to 500 ℃ according to a certain heating program, and keeping the temperature for 12 hours; cooling to room temperature along with the furnace to obtain a crude product 4;

(e) and dissolving the crude product 4 in an organic solvent, filtering, vacuumizing, and distilling under reduced pressure to obtain the polycarbosilane PCS.

(6) And taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

The surface cleaning method comprises the following steps: firstly, the surface is polished by sand paper, then the surface is cleaned in ethanol, and finally the surface is dried at 60 ℃.

Example 4

The same as example 1 except that: except that rod-shaped alumina was used in an amount of the sum of the weights of the rod-shaped alumina and the flake-shaped alumina in example 1.

Example 5

The same as example 1 except that: except that the tabular alumina was used in an amount of the sum of the weights of the rod-shaped alumina and the tabular alumina in example 1.

Comparative example 1

The preparation method of the silicon carbide ceramic material comprises the following steps:

(1) pressing: adding a sintering aid into the silicon carbide mixed slurry, immersing an alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould for pressurization to perform compression molding to obtain a silicon carbide ceramic biscuit;

the weight of the sintering aid is 3% of that of the silicon carbide powder; the dipping time is 1.5 h; the pressing pressure is 200MPa/cm²The pressing time is 5 s; the weight ratio of the alumina fiber cloth to the silicon carbide is 10: 60.

(2) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2150 ℃, and the sintering time is 2 h.

(3) Enhancing: putting the silicon carbide ceramic material obtained in the step (2) into a reaction kettle, introducing inert gas, pressurizing to 2.5MPa, heating to 1550 ℃ at the speed of 8 ℃/min, preserving heat for 3h, furnace-cooling to 750 ℃ and preserving heat for 1.5 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of polycarbosilane in the reaction kettle reaches 0.3mol/L, heating to 1300 ℃ at the speed of 8 ℃/min and preserving heat for 6 hours; then stopping introducing polycarbosilane, keeping the flow of the inert gas at 150ml/min, and cooling to room temperature along with the furnace;

the preparation method of the polycarbosilane is the same as that of example 1.

(4) And taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

The surface cleaning method comprises the following steps: firstly, the surface is polished by sand paper, then the surface is cleaned in ethanol, and finally the surface is dried at 70 ℃.

Comparative example 2

The preparation method of the silicon carbide ceramic material comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

the zirconium hydrogen phosphate dispersion also comprises ethylene diamine tetraacetic acid, and the pH value is adjusted to 3.5; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g:200 mL; the airing conditions are as follows: keeping the temperature for 1.5h at 50-70 ℃.

(2) Pressing: adding a sintering aid into the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould for pressurization to perform compression molding, and obtaining a silicon carbide ceramic biscuit;

the weight of the sintering aid is 3% of that of the silicon carbide powder; the dipping time is 1.5 h; the pressing pressure is 200MPa/cm²The pressing time is 5 s; the weight ratio of the alumina fiber cloth to the silicon carbide is 10: 60.

(3) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2150 ℃, and the sintering time is 2 h.

(4) Enhancing: putting the silicon carbide ceramic material obtained in the step (3) into a reaction kettle, introducing inert gas, pressurizing to 2.5MPa, heating to 1550 ℃ at the speed of 8 ℃/min, preserving heat for 3h, furnace-cooling to 750 ℃ and preserving heat for 1.5 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of polycarbosilane in the reaction kettle reaches 0.3mol/L, heating to 1300 ℃ at the speed of 8 ℃/min and preserving heat for 6 hours; then stopping introducing polycarbosilane, keeping the flow of the inert gas at 150ml/min, and cooling to room temperature along with the furnace;

the preparation method of the polycarbosilane is the same as that of example 1.

(5) And taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

The surface cleaning method comprises the following steps: firstly, the surface is polished by sand paper, then the surface is cleaned in ethanol, and finally the surface is dried at 70 ℃.

Comparative example 3

The preparation method of the silicon carbide ceramic material comprises the following steps:

(1) pressing: adding rod-shaped alumina and flake-shaped alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; adding the rest of silicon carbide powder and sintering aid, and adding the silicon carbide powder and the sintering aid into a steel die to pressurize and press and form to obtain a silicon carbide ceramic biscuit;

the weight ratio of the rod-shaped alumina to the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is 5: 20: 2.5: 2.5, the weight ratio of the rod-shaped alumina to the flake-shaped alumina is 1: 2; the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethyl cellulose or tetramethyl ammonium hydroxide, and the weight of the dispersing agent is 0.6 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin;

the weight of the sintering aid is 3 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 1.5 h; the pressing pressure is 200MPa/cm²The pressing time is 5 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: 60.

(2) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2150 ℃, and the sintering time is 2 h.

(3) Enhancing: putting the silicon carbide ceramic material obtained in the step (2) into a reaction kettle, introducing inert gas, pressurizing to 2.5MPa, heating to 1550 ℃ at the speed of 8 ℃/min, preserving heat for 3h, furnace-cooling to 750 ℃ and preserving heat for 1.5 h; introducing polycarbosilane into the reaction kettle by taking inert gas as carrier gas; when the concentration of polycarbosilane in the reaction kettle reaches 0.3mol/L, heating to 1300 ℃ at the speed of 8 ℃/min and preserving heat for 6 hours; then stopping introducing polycarbosilane, keeping the flow of the inert gas at 150ml/min, and cooling to room temperature along with the furnace;

the preparation method of the polycarbosilane is the same as that of example 1.

(4) And taking out the reinforced silicon carbide ceramic material, and cleaning the surface to obtain the alumina fiber reinforced silicon carbide ceramic material.

The surface cleaning method comprises the following steps: firstly, the surface is polished by sand paper, then the surface is cleaned in ethanol, and finally the surface is dried at 70 ℃.

Comparative example 4

The preparation method of the silicon carbide ceramic material comprises the following steps:

(1) preparing modified alumina fiber cloth: dispersing zirconium hydrogen phosphate into water at room temperature to obtain a zirconium hydrogen phosphate dispersion; vacuum impregnation is carried out on the alumina fiber cloth by adopting zirconium hydrogen phosphate dispersion at vacuum and room temperature; drying the alumina fiber cloth subjected to vacuum impregnation to obtain modified alumina fiber cloth;

the zirconium hydrogen phosphate dispersion also comprises ethylene diamine tetraacetic acid, and the pH value is adjusted to 3.5; the dosage ratio of the zirconium hydrogen phosphate to the water is 1g:200 mL; the airing conditions are as follows: keeping the temperature for 1.5h at 50-70 ℃.

(2) Preparing a modified alumina fiber cloth layer: adding rod-shaped alumina and flake-shaped alumina into water, adding silicon carbide powder, graphite powder and phenolic resin, and uniformly stirring to obtain silicon carbide mixed slurry; uniformly spraying partial silicon carbide slurry on the surface of the modified alumina fiber cloth, laminating the modified alumina fiber cloth sprayed with slurry in multiple layers, and needling by using a needle with barbs to obtain the modified alumina fiber cloth layer;

the weight ratio of the rod-shaped alumina to the sheet-shaped alumina to the silicon carbide powder to the graphite powder to the phenolic resin is 5: 20: 2.5: 2.5, the weight ratio of the rod-shaped alumina to the flake-shaped alumina is 1: 2; the silicon carbide mixed slurry can also comprise a dispersing agent, wherein the dispersing agent is sodium carboxymethyl cellulose or tetramethyl ammonium hydroxide, and the weight of the dispersing agent is 0.6 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the thickness of the laminated modified alumina fiber cloth layer of the multilayer spraying slurry is 2 mm.

(3) Pressing: adding a sintering aid into the balance of the silicon carbide mixed slurry, immersing the modified alumina fiber cloth layer into the silicon carbide mixed slurry for impregnation, drying the silicon carbide mixed slurry by using a steam drying box, adding the dried silicon carbide mixed slurry into a steel mould after drying, and pressurizing to perform compression molding to obtain a silicon carbide ceramic biscuit;

the weight of the sintering aid is 3 percent of the total weight of the rodlike alumina, the flaky alumina, the silicon carbide powder, the graphite powder and the phenolic resin; the dipping time is 1.5 h; the pressing pressure is 200MPa/cm²The pressing time is 5 s; the weight ratio of the alumina fiber cloth to the silicon carbide mixed slurry is 10: 60.

(4) and (3) sintering: sintering the silicon carbide ceramic biscuit in a vacuum furnace to obtain a silicon carbide ceramic material; the sintering temperature is 2150 ℃, and the sintering time is 2 h.

Examples of the experiments

The product properties of examples 1 to 5 and comparative examples 1 to 4 were tested. The results are as follows:

the above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.