High-density SiC / SiC composite material with uniformly distributed self-healing components and application of preparation method of high-density SiC / SiC composite material

Abstract

The invention relates to a high-density SiC / SiC composite material with uniformly distributed self-healing components and application of a preparation method of the high-density SiC / SiC composite material. UV-curable SiCw-SiBOC precursor slurry is pre-cured on the surface of two-dimensional SiC fiber cloth, stacked and compacted in a mold and then subjected to thermocuring to be qualitative as a SiC cellulose blank; the densification of the self-healing SiC / SiC composite material is realized through inert atmosphere cracking and reaction melt permeation under a vacuum condition. And uniform distribution of self-healing components such as B4C and SiBC in the two-dimensional SiC fiber cloth layers and between the two-dimensional SiC fiber cloth layers is realized. After the self-healing component is oxidized, diboron trioxide glass and borosilicate glass are generated to seal and fill matrix cracks so as to realize matrix self-healing, so that the whole water-oxygen service environment self-healing performance of the composite material is effectively improved. A high-toughness SiCw phase is introduced as an initial site of a carbon-silicon reaction, so that a part of pores among fiber bundles and pores among fiber cloth layers can be filled, and the problem of low fracture toughness caused by continuous distribution of a self-healing phase can be solved.

Description

Technical Field

[0001] The present invention relates to composite materials and preparation methods thereof, and in particular to a high-density SiC / SiC composite material with uniformly distributed self-healing components and application of the preparation method thereof. Background Art

[0002] SiC fiber-reinforced SiC ceramic matrix composites (SiC / SiC composites) offer significant advantages in high-temperature, high-stress service environments in the aerospace sector due to their excellent properties, including low density, high specific strength, high specific modulus, and non-catastrophic fracture. Among them, SiC / SiC composites with 2D woven SiC fibers (such as non-woven, plain, and satin weaves) are the most widely used, often in aerospace engine hot-end components such as regulating plates and combustion chambers. However, in the high-temperature, thermodynamically coupled oxygen environment of aerospace engines, water-oxygen corrosion of SiC / SiC composites can easily trigger matrix cracking, further corroding the fibers, causing material damage and significantly shortening their service life. Therefore, improving their antioxidant properties is key to extending service life and improving aerospace engine efficiency. Research has shown that the introduction of boron-containing self-healing components can effectively enhance antioxidant properties. The liquid-phase boron-containing oxides generated by oxidation can fill cracks through viscous flow, preventing oxygen from diffusing into the matrix and causing cracking, thereby protecting the fibers.

[0003] Patent No. CN200910021047.5 discloses a method for preparing a self-healing SiC / SiC composite material using a chemical vapor infiltration (CVI) process, which involves alternately depositing a silicon carbide and boron carbide matrix and applying a silicon carbide coating. However, the matrix prepared by this process has a high porosity and large pore size, resulting in insufficient sealing efficiency of the silicon-boron self-healing component and an inability to effectively prevent the rapid penetration of water and oxygen. This inherent porous structure of the matrix limits the protective effect of the self-healing component in high-temperature oxidizing environments, making it difficult to meet the high requirements of aircraft engines for the material's antioxidant properties.

[0004] Patent No. CN202210239625.8 discloses a method for preparing a dense SiC fiber / Si-YBC composite material by vacuum infiltration of B4C slurry and combining Si-Y alloy infiltration through a reactive melt infiltration (RMI) process. Although the process can form a dense matrix, the introduction of the B source through SI slurry infiltration results in an uneven distribution of self-healing components, with a higher content of self-healing components in the outer area and less in the inner area. This uneven distribution weakens the overall oxidation resistance of the material, especially in long-term high-temperature service environments, where the oxidation resistance of the internal area of ​​the composite material is insufficient.

[0005] The paper "Effect of heat flux on ablation behavior and mechanism of C / C-ZrB2-SiC composite under oxyacetylene torch flame" studied the ablation behavior of C / C-ZrB2-SiC composites and found that the precursor infusion pyrolysis (PIP) process can produce composites with uniform component distribution. However, this process requires multiple cycles (up to 14) to introduce ZrB2 and SiC, resulting in long manufacturing cycles and high costs.

[0006] The above-mentioned existing technologies show that although the CVI, RMI and PIP processes each have their own advantages in the preparation of SiC / SiC composite materials, they all have certain limitations. The CVI process has a high matrix porosity, which limits the sealing efficiency of the self-healing components; although the RMI process can produce a dense matrix, the self-healing components are unevenly distributed; although the PIP process has a uniform distribution of components, the manufacturing cycle is long and the cost is high. These shortcomings indicate that there is an urgent need to develop a new preparation method that can efficiently and evenly introduce self-healing components, while shortening the manufacturing cycle and reducing costs to meet the demand for high-performance SiC / SiC composites in aircraft engines. Summary of the Invention

[0007] Technical problems to be solved

[0008] In order to avoid the shortcomings of the prior art, the present invention proposes a high-density SiC / SiC composite material with uniform distribution of self-healing components and the application of its preparation method, through a series of combined processes including light-curing pre-shaped prepreg, thermal curing shaping blank, inert atmosphere cracking and forming SiC fiber preform and reactive melt infiltration (RMI) to prepare a high-density SiC / SiC composite material with uniform distribution of self-healing components.

[0009] Technical Solution

[0010] A high-density SiC / SiC composite material with uniformly distributed self-healing components, characterized in that: a SiBOC ceramic precursor that can be cured by ultraviolet light is used as a self-healing modified boron source, SiC w -SiBOC precursor slurry is evenly dispersed on the two-dimensional SiC fiber cloth by light curing to obtain SiC uniformly distributed on the SiC cloth. w -SiBOC ceramic precursor, realizing self-healing component B element and interlayer reinforcement phase SiC w Uniform distribution of SiC in composite materials w , B4C and SiBC are evenly distributed in the SiC matrix after the reaction melt infiltration; the SiC generated by the reaction is along the SiC wThe composite material grows in a radial direction and is overlapped and inlaid with each other to improve the strength and toughness of the matrix; the porosity of the composite material is less than 8%, and the bending strength retention rate after oxidation at 1300°C for 50 hours is greater than 80%.

[0011] A method for preparing a high-density SiC / SiC composite material with uniform distribution of the self-healing components, characterized by the following steps:

[0012] Step 1: UV-curable SiC w -Preparation of SiBOC ceramic precursor slurry: SiBoc with a mass fraction of 25-40 wt.% w , 25-32 wt.% of a photocurable SiBOC ceramic precursor resin, 25-32 wt.% of a diluent, 3-5 wt.% of a dispersant, 1 wt.% of a photoinitiator and 3-5 wt.% of a light absorber are mixed and dispersed, ball milled, and a UV-curable SiC is obtained. w -SiBOC ceramic precursor slurry;

[0013] Step 2: Photocuring pre-shaped two-dimensional SiC fiber prepreg: The UV-curable SiC obtained in step 1 is w - SiBOC ceramic precursor slurry is evenly coated on SiC fiber cloth, and the UV power is 80-90mW / cm 2 Under light-curing conditions, simultaneous UV pre-curing of the slurry coating is achieved to obtain a light-cured two-dimensional SiC fiber prepreg;

[0014] Step 3, thermally curing and shaping the SiC cellulose blank: the two-dimensional SiC fiber prepreg obtained by light curing in step 2 is laminated, compacted and shaped, and then placed in an oven for thermal curing to obtain a SiC cellulose blank;

[0015] Step 4, inert atmosphere cracking SiC fiber preform: placing the heat-cured and shaped SiC cellulose blank in a vacuum furnace, heating it to 1200-1400°C at a heating rate of 1°C / min or 2°C / min in an argon atmosphere of 100-200 sccm and keeping it warm for 3 hours, and setting three 1-3 hour holding sections at 200-300°C, 400-600°C and 700-800°C during the heating process, finally cooling it to 400-600°C at a rate of 2-5°C / min and cooling it to room temperature with the furnace, so that the SiBOC precursor is fully cracked and evenly covers the SiC fiber and SiC w , forming a SiC fiber preform;

[0016] Step 5: Prepare the self-healing modified matrix by reactive melt infiltration: SiC fiber preform is coated with Si powder and encapsulated with graphite paper, and then the whole is placed in a vacuum furnace at a vacuum degree of 5×10 2Pa, the temperature is 1500 ℃ ~ 1600 ℃, the reaction melt infiltration is completed after the reaction is carried out for 40 to 80 minutes, and a high-density SiC / SiC composite material with uniform distribution of self-healing components is obtained.

[0017] The thickness of the SiC cellulose blank in step 3 is 1 to 6 mm.

[0018] The two-dimensional SiC fiber prepreg stack is compacted and shaped using a graphite mold.

[0019] The SiC of step 1 w Surface treatment: SiC w The powder is placed in a vacuum heat treatment furnace at a temperature of 1600-1700°C for 1-2 hours to improve the surface smoothness. w The powder is placed in a box furnace, the treatment temperature is 900-1050℃, the treatment time is 30-90min, and the SiC with nano-scale SiO2 film on the surface is obtained. w .

[0020] The slurry dispersion: the SiC w The mixture with the photosensitive precursor is first dispersed in a vacuum mixer for 15 to 30 minutes, and then placed in a planetary ball mill for 6 to 8 hours, with a ball-to-material ratio of 3:1 to 2:1 and a rotation speed controlled at 200 to 300 r / min. The viscosity of the obtained slurry is at room temperature and a shear rate of 100s -1 1~6Pa·s -1 .

[0021] In the thermal curing process of the SiC cellulose blank in step 2, the prepreg laminate and the mold are placed in an oven and heated to 170-200° C. at a heating rate of 5-10° C. / min, and kept at this temperature for 60-90 minutes to fully crosslink and cure the precursors between the fibers.

[0022] The diluent is 1,6-hexanediol diacrylate HDDA; the dispersant is one or more of KOS110, Solsperse41000, Solsperse17000, BYK110, and silane coupling agent KH550; the photoinitiator is one of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide 819 and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide TPO; the light absorber is Sudan red, phosphor BaMgAl 10 O 17 :Eu BAM:Eu 2+ and one or more of Sr5(PO4)3Cl:Eu.

[0023] A photocuring system for two-dimensional SiC fiber prepreg, characterized in that it includes a first main rotating shaft, a first slave rotating shaft, a second main rotating shaft, a second slave rotating shaft, a glass plate, a release film, an ultraviolet curing light source, a polytetrafluoroethylene material cylinder, a bracket, a front scraper and a rear scraper; a release film is provided on the glass plate, one end of the release film is wound around the first main rotating shaft, and the other end of the release film is located on the second main rotating shaft; a first slave rotating shaft and a second slave rotating shaft are respectively provided on both sides of the glass plate, the release film is placed on the glass plate through the two slave rotating shafts, and moves on the glass plate with the first main rotating shaft under the traction of the second main rotating shaft; a polytetrafluoroethylene material cylinder, a bracket and an ultraviolet curing light source are sequentially provided on the glass plate along the moving direction of the release film, and a front scraper and a rear scraper are provided on the bracket; the distance between the front scraper and the release film is longer than the distance between the rear scraper and the release film.

[0024] A method for using a photocuring system for two-dimensional SiC fiber prepreg is characterized in that: during operation, slurry is placed in a polytetrafluoroethylene material cylinder, and the two-dimensional SiC fiber is placed on a release film; the release film drives the two-dimensional SiC fiber through the polytetrafluoroethylene material cylinder, and the slurry is laid on the two-dimensional SiC fiber; the release film drives the two-dimensional SiC fiber through a bracket, and the front scraper and the rear scraper on the bracket evenly coat the slurry on the two-dimensional SiC fiber; then the two-dimensional SiC fiber passes through a UV curing light source area, so that the two-dimensional SiC fiber coated with the slurry is cured; the distance between the front scraper and the release film, as well as the distance between the rear scraper and the release film, is adjusted, and the difference between the two distances is the thickness of the slurry.

[0025] Beneficial effects

[0026] The present invention proposes a high-density SiC / SiC composite material with uniform distribution of self-healing components and its preparation method, which is used to solve the problem that the self-healing SiC / SiC composite material prepared by the existing technology is difficult to meet the requirements of high density, high toughness and uniform distribution of self-healing components (containing boron elements, such as B4C or SiBC). The technical solution is to use a doctor blade coating combined with UV curing to coat the UV-curable SiC w -SiBOC precursor slurry is pre-cured on the surface of two-dimensional SiC fiber cloth. Multiple pre-cured two-dimensional SiC fiber cloths are stacked in a mold, compacted, and then thermally cured to form SiC cellulose blanks. Then, the densification of the self-healing SiC / SiC composite material is achieved by inert atmosphere cracking and reactive melt infiltration under vacuum conditions. The combined process of doctor blade coating combined with UV pre-curing and mold pressing thermal curing can achieve uniform distribution of self-healing components such as B4C and SiBC within and between two-dimensional SiC fiber cloth layers. After oxidation, the self-healing components generate boron trioxide glass and silicon boron glass to seal the matrix cracks to achieve matrix self-healing, which effectively improves the overall self-healing performance of the composite material in water and oxygen service environment. The introduction of high-strength and tough SiC wThe phase is the starting point of the carbon-silicon reaction, which can not only fill a part of the pores between fiber bundles and fiber cloth layers, but also make up for the problem of low fracture toughness caused by the continuous distribution of the self-healing phase.

[0027] In the present invention:

[0028] 1. The boron-containing component is introduced into the matrix of the composite material through two rounds of curing using a photocurable SiBOC ceramic precursor as a carrier. In particular, in the precuring step, the preparation of the two-dimensional SiC fiber prepreg utilizes the efficiency and convenience of ultraviolet curing to achieve the simultaneous coating and curing of the precursor slurry on the SiC fiber cloth, which improves the single-layer preparation efficiency of the prepreg. On the other hand, timely ultraviolet curing ensures that the boron-containing component is uniformly dispersed on the SiC fiber cloth and will not be affected by gravity and the pore structure of the fiber cloth, causing uneven distribution of the boron-containing component in the layer. Unlike the existing process method of introducing boron-containing components into a three-dimensional preform, the uniform introduction of boron-containing components directly on the two-dimensional fiber cloth lays a solid foundation for the uniform distribution of boron-containing components in the composite material matrix after densification, and effectively improves the overall self-healing performance of the composite material in water and oxygen service environment.

[0029] 2. SiC w As an interlayer high-strength and tough phase, it is also evenly distributed within and between the fiber cloth layers. On the one hand, it prevents the self-healing modified phase from being too continuous and reducing the fracture toughness, thereby increasing the matrix cracking energy; on the other hand, the whiskers serve as nucleation sites for the carbon-silicon reaction, which can enable the SiC generated by the reaction to grow in a specific direction, overlap and embed with each other, and at the same time increase the crack propagation path, improve the matrix strength and toughness, and effectively alleviate the problem of poor fracture toughness of the matrix of traditional self-healing modified SiC / SiC composite materials.

[0030] Due to SiC w The scattering and absorption losses of ultraviolet light are very large, resulting in poor ultraviolet curing performance of the ultraviolet curable precursor paste with whiskers added. The characteristic of the light absorber is that it specifically absorbs the ultraviolet light source from the ultraviolet curing lamp at 405nm and uses the short afterglow effect of its fluorescence to continuously provide energy to the photoinitiator in a short time to more fully initiate the light curing of the photosensitive precursor inside the paste, alleviating the SiC w Negative impact on the curing performance of light-curing paste. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 :It is the process flow chart of the preparation method involved in the present invention

[0032] Figure 2 Schematic diagram of the slurry coating and UV pre-curing device used to prepare SiC fiber prepreg

[0033] 1-Second main shaft, 2-Second slave shaft, 3-UV curing light source, 4-Bracket, 5-Rear scraper, 6-Front scraper, 7-Release film, 8-PTFE cylinder, 9-UV curable SiC w -SiBOC ceramic precursor slurry, 10-first slave rotating shaft, 11-first main rotating shaft, 12-glass plate;

[0034] Figure 3 This is a backscattered (BSE) photograph of the polished morphology of the high-density SiC / SiC composite material matrix with uniform distribution of self-healing components prepared in Example 1.

[0035] Figure 4 X-ray photoelectron spectroscopy (XPS) graphs of the B element in the internal matrix of the highly dense SiC / SiC composite materials with uniformly distributed self-healing components prepared in Examples 1, 2 and 3. DETAILED DESCRIPTION

[0036] The present invention will now be further described with reference to the embodiments and accompanying drawings:

[0037] A method for preparing a high-density SiC / SiC composite material with uniform distribution of the self-healing components, characterized by the following steps:

[0038] Step 1: UV-curable SiC w -Preparation of SiBOC ceramic precursor slurry:

[0039] The mass fraction of SiC after surface treatment is 25-40wt.% w , 25-32 wt.% of UV-curable SiBOC ceramic precursor resin, 25-32 wt.% of diluent 1,6-hexanediol diacrylate, 3-5 wt.% of dispersants KOS110, Solsperse41000, Solsperse17000, BYK110, one or more of silane coupling agent KH550, 1 wt.% of photoinitiators phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide 819 and diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide TPO, and 3-5 wt.% of light absorber Sudan red, phosphor BaMgAl 10 O 17 :Eu(BAM:Eu 2+ ) and one or more of Sr5(PO4)3Cl:Eu are mixed in a vacuum stirring tank;

[0040] The above SiC w The mixture with the photosensitive precursor is first dispersed in a vacuum mixer at level 3 speed for 15 to 30 minutes;

[0041] The dispersed mixture was placed in a planetary ball mill with a ball-to-material ratio of 3:1-2:1 and a ball milling bead size of 4mm:6mm:8mm=5:3:2. The ball mill was milled for 6-8 hours at a speed of 200-300 r / min.

[0042] Viscometer measurement of ball-milled UV-curable SiC w -SiBOC ceramic precursor slurry, slurry viscosity at room temperature, shear rate of 100s -1 1~6Pa·s -1 .

[0043] SiC w Surface treatment:

[0044] Step (1) SiC with a diameter of 600nm and a length of 10-50μm w The powder is placed in a graphite crucible and placed in a vacuum heat treatment furnace, and the temperature is raised to 1600-1700℃ at a heating rate of 10℃ / min and kept at this temperature for 1-2h to improve the SiC w Surface flatness.

[0045] Step (2) heat-treated SiC w The powder is placed in an alumina crucible and placed in a box furnace, and the temperature is raised to 900-1050°C at a heating rate of 5°C / min and kept at this temperature for 30-90min to obtain SiC with a surface coated with a nano-scale SiO2 film. w .

[0046] The diluent is 1,6-hexanediol diacrylate HDDA; the dispersant is one or more of KOS110, Solsperse41000, Solsperse17000, BYK110, and silane coupling agent KH550; the photoinitiator is one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO); the light absorber is Sudan red, phosphor BaMgAl 10 O 17 :Eu(BAM:Eu 2+ ) and one or more of Sr5(PO4)3Cl:Eu.

[0047] The slurry dispersion: the SiC w The mixture with the photosensitive precursor was first dispersed in a vacuum mixer at gear 3 for 15 to 30 minutes, and then placed in a planetary ball mill for 6 to 8 hours, with a ball-to-material ratio of 3:1 and a speed controlled at 200 to 300 r / min. The viscosity of the obtained slurry was -1 1~6Pa·s -1 .

[0048] The SiC w The diameter is 600nm and the length is 10-50μm.

[0049] Step 2: Photocuring of pre-shaped two-dimensional SiC fiber prepreg:

[0050] UV-curable SiC prepared using digital light processing 3D printer test step 2 w -The cured thickness of SiBOC ceramic precursor slurry reaches 360-450mJ / cm 2 The curing depth under the ultraviolet radiation dose is 75 to 150 μm;

[0051] SiC fiber cloth (SiC plain cloth, two-dimensional plain weave SiC cloth, two-dimensional satin weave SiC cloth) was cut into a cuboid with a length and width of 250 mm × 150 mm;

[0052] Use Figure 2 The light-curing prepreg device shown in the figure fixes the two-dimensional SiC fiber cloth flatly on the release film between the rotating shafts, and uses a micrometer to adjust the scraper height to ensure that the height difference between the rear scraper and the fiber cloth is controlled within 200-500μm, and the front scraper is 200μm higher than the rear scraper. w - SiBOC ceramic precursor slurry into a polytetrafluoroethylene cylinder;

[0053] Turn on the rotating shaft and UV lamp, adjust the rotating shaft speed to 10-30r / min so that the slurry is evenly coated on the fiber cloth, and adjust the UV light power to 80-90mW / cm 2 Achieve simultaneous UV pre-curing of slurry coating;

[0054] The SiC fiber cloth includes two-dimensional SiC flat cloth, two-dimensional plain weave SiC cloth, and two-dimensional satin weave SiC cloth; the SiC fiber cloth is cut into a rectangular parallelepiped with a length and width of 250 mm×150 mm.

[0055] Precured SiC fiber cloth prepreg slurry coating and UV precuring device Figure 2 As shown, the apparatus comprises a rotating shaft, a release film, a UV curing light source, a bracket, a rear scraper, a front scraper, a polytetrafluoroethylene material bar and a glass plate. The rotation direction and speed of the rotating shaft and the light intensity of the UV curing light source are all adjustable.

[0056] The specific layout of the system is:

[0057] It includes a first main rotating shaft 11, a first slave rotating shaft 10, a second main rotating shaft 1, a second slave rotating shaft 2, a glass plate 12, a release film 7, a UV curing light source 3, a polytetrafluoroethylene material cylinder 8, a bracket 4, a front scraper 6 and a rear scraper 5; a release film 7 is provided on the glass plate 12, one end of the release film 7 is wound around the first main rotating shaft 11, and the other end of the release film 7 is located on the second main rotating shaft 1; a first slave rotating shaft 10 and a second slave rotating shaft 2 are respectively provided on both sides of the glass plate 12, the release film 7 is placed on the glass plate through the two slave rotating shafts, and moves on the glass plate with the first main rotating shaft under the traction of the second main rotating shaft 1; a polytetrafluoroethylene material cylinder 8, a bracket 4 and a UV curing light source 3 are sequentially provided on the glass plate 12 along the moving direction of the release film 7, and a front scraper 6 and a rear scraper 5 are provided on the bracket; the distance between the front scraper and the release film is longer than the distance between the rear scraper and the release film.

[0058] A method for using a two-dimensional SiC fiber prepreg light curing system, characterized in that: during operation, slurry is placed in a polytetrafluoroethylene material cylinder, and the cut two-dimensional SiC fiber cloth is flatly fixed on a release film between rotating shafts;

[0059] Use a micrometer to adjust the scraper height, control the height difference between the rear scraper and the fiber cloth at 150-300 μm, and the front scraper is 200 μm higher than the rear scraper.

[0060] The prepared UV-curable SiC w - SiBOC ceramic precursor slurry is added to the polytetrafluoroethylene material cylinder, then the shaft and UV lamp are turned on, and the shaft speed is adjusted to 10-30r / min so that the slurry is evenly coated on the fiber cloth. The release film drives the two-dimensional SiC fiber through the polytetrafluoroethylene material cylinder, and the slurry is laid on the two-dimensional SiC fiber; the release film drives the two-dimensional SiC fiber through the bracket, and the front and rear scrapers on the bracket evenly coat the slurry on the two-dimensional SiC fiber;

[0061] Then pass through the UV curing light source area and adjust the UV light power to 80-90mW / cm 2 The slurry coating is simultaneously pre-cured by ultraviolet light, so that the two-dimensional SiC fiber coated with the slurry is cured; the distance between the front scraper and the release film, as well as the distance between the rear scraper and the release film are adjusted. The difference between the two distances is the thickness of the slurry.

[0062] Step 3: Thermally solidify and shape the SiC cellulose blank:

[0063] The two-dimensional SiC fiber prepreg prepared in step 2 is laminated, compacted and shaped using a graphite mold, and then placed in an oven for thermal curing to obtain a SiC cellulose blank with a thickness of 1 to 6 mm;

[0064] Thermal curing process of SiC cellulose blank: The prepreg stack and the mold are placed in an oven and heated to 170-200°C at a heating rate of 10°C / min. The temperature is kept at this temperature for 60-90 minutes to fully crosslink and cure the precursors between the fibers, obtaining a SiC cellulose blank with a thickness of 1-6 mm.

[0065] Step 4: Pyrolysis of SiC fiber preform in inert atmosphere:

[0066] The SiC cellulose blank after heat curing and shaping was placed in a vacuum furnace, and heated to 1200-1400℃ at a heating rate of 1℃ / min or 2℃ / min in an argon atmosphere of 100-200sccm and kept warm for 3h. During the heating process, three 2h holding sections were set at 250℃, 500℃ and 750℃. Finally, the temperature was lowered to 500℃ at a rate of 5℃ / min and cooled to room temperature with the furnace, so that the SiBOC precursor was fully cracked and evenly coated with SiC fibers and SiC w , forming a SiC fiber preform;

[0067] Step 5: Preparation of self-healing modified matrix by reactive melt infiltration:

[0068] The SiC fiber preform was coated with Si powder and encapsulated with graphite paper. The whole preform was then placed in a vacuum furnace at a vacuum degree of 5×10 2 Pa, under the condition of temperature of 1500℃~1600℃, the reaction time is 40~80min to complete the reaction melt infiltration.

[0069] Reference Figure 1 The following examples illustrate the present invention in detail by taking the preparation of a two-dimensional SiC / SiC composite material with uniformly distributed self-healing components as an example.

[0070] Example 1

[0071] Step 1SiC w Surface treatment:

[0072] Step 1.1 SiC with a diameter of 600 nm and a length of 10-50 μm w The powder was placed in a graphite crucible and placed in a vacuum heat treatment furnace and heated to 1600℃ for 2 hours to improve the SiC w Surface flatness.

[0073] Step 1.2 Heat-treated SiC w The powder was placed in an alumina crucible and placed in a box furnace and heated to 900℃ for 90 minutes to obtain SiC coated with nano-scale SiO2 film. w .

[0074] Step 2: Prepare UV-curable SiC w-SiBOC ceramic precursor slurry:

[0075] Step 2.1 The surface is treated to a mass fraction of 25wt.% SiC w , 32 wt.% of UV-curable SiBOC ceramic precursor resin, 32 wt.% of diluent 1,6-hexanediol diacrylate HDDA, 5 wt.% of dispersant KOS110, 1 wt.% of photoinitiator diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide TPO and 5 wt.% of light absorber Sudan Red are mixed in a vacuum stirring tank.

[0076] Step 2.2 Place the above SiC w The mixture with the photosensitive precursor was first dispersed in a vacuum mixer at level 3 for 15 minutes.

[0077] Step 2.3: Place the dispersed mixture into a planetary ball mill with a ball-to-material ratio of 2:1 and a ball milling bead size of 4 mm:6 mm:8 mm = 5:3:2. Mill for 6 h at a speed of 200 r / min.

[0078] Step 2.4 Use viscometer to measure the UV-curable SiC obtained by ball milling w -SiBOC ceramic precursor slurry, slurry viscosity at room temperature, shear rate of 100s -1 1.9 Pa·s -1 .

[0079] Step 3: Photocuring of pre-shaped two-dimensional SiC fiber prepreg:

[0080] Step 3.1 Test the UV-curable SiC prepared in step 2 using a digital light processing 3D printer w -The cured thickness of SiBOC ceramic precursor slurry reaches 360mJ / cm 2 The curing depth under the UV radiation dose is 139μm.

[0081] Step 3.2: Cut the SiC non-woven fabric into a rectangular parallelepiped with a length and width of 250 mm × 150 mm.

[0082] Step 3.3: Flatten and fix the cut two-dimensional SiC free-weft fabric on the release film between the rotating shafts, and use a micrometer to adjust the scraper height to control the height difference between the rear scraper and the fiber cloth to 150 μm.

[0083] Step 3.4: Prepare the UV-curable SiC w - SiBOC ceramic precursor slurry was added to the polytetrafluoroethylene cylinder, and then the shaft and UV lamp were turned on. The shaft speed was adjusted to 25 r / min so that the slurry was evenly coated on the fiber cloth. The UV light power was adjusted to 80 mW / cm 2Realize simultaneous UV pre-curing of slurry coating.

[0084] Replace the fiber cloth and repeat step 3 to pre-solidify multiple cut two-dimensional SiC fiber cloths to meet the thickness requirement of the green blank after stacking, compaction and thermal curing.

[0085] Step 4: Heat curing and shaping the SiC cellulose blank:

[0086] Step 4.1: Use a graphite mold to stack and compact the two-dimensional SiC fiber prepreg prepared in step 3.

[0087] Step 4.2: Place the prepreg laminate and the mold in an oven and heat it to 170°C at a heating rate of 10°C / min. Maintain the temperature for 60 minutes to allow the precursors between the fibers to fully crosslink and solidify, obtaining a SiC cellulose blank with a thickness of 2.2 mm.

[0088] Step 5: Inert atmosphere cracking and forming SiC fiber preform:

[0089] The SiC cellulose blank after heat curing was placed in a vacuum furnace and heated to 1200℃ at a heating rate of 1℃ / min or 2℃ / min under 100sccm argon atmosphere and kept warm for 3h. During the heating process, three 1.5h holding sections were set at 200℃, 400℃ and 700℃. Finally, the temperature was lowered to 600℃ at a rate of 2℃ / min and cooled to room temperature with the furnace, so that the SiBOC precursor was fully cracked and evenly coated on the SiC fibers and SiC w , forming a SiC fiber preform;

[0090] Step 6: Preparation of a uniform self-healing modified matrix by reaction melt infiltration:

[0091] The SiC fiber preform was coated with Si powder and encapsulated with graphite paper. The whole preform was then placed in a vacuum furnace at a vacuum degree of 5×10 2 Pa, the temperature is 1500℃, and the reaction melt infiltration is completed after 45 minutes of reaction.

[0092] The density of the prepared SiC / SiC composite material measured by the Archimedean drainage method was 2.68 g / cm 3 , the open porosity is 7.31%. Figure 3 It shows that the self-healing phase and whisker toughening phase introduced into the matrix are dispersed and evenly distributed. Figure 4 BO and BC bonds were detected within the composite matrix, further demonstrating the uniform distribution of the self-healing components within the composite matrix. Tests revealed that the SiC / SiC composite retained 80.96% of its flexural strength after oxidation at 1300°C for 50 hours. The self-healing modified material exhibited excellent resistance to water and oxygen corrosion.

[0093] Example 2

[0094] Step 1SiC w Surface treatment:

[0095] Step 1.1 SiC with a diameter of 600 nm and a length of 10-50 μm w The powder was placed in a graphite crucible and placed in a vacuum heat treatment furnace, and the temperature was raised to 1700℃ at a heating rate of 10℃ / min and kept at that temperature for 1h to improve the SiC w Surface flatness.

[0096] Step 1.2 Heat-treated SiC w The powder was placed in an alumina crucible and placed in a box furnace, and the temperature was raised to 950°C at a heating rate of 5°C / min and kept at this temperature for 60 min to obtain SiC with a surface coated with a nano-scale SiO2 film. w .

[0097] Step 2: Prepare UV-curable SiC w -SiBOC ceramic precursor slurry:

[0098] Step 2.1 The surface is treated to a mass fraction of 31wt.% SiC w , 30 wt.% of UV-curable SiBOC ceramic precursor resin, 30 wt.% of diluent 1,6-hexanediol diacrylate HDDA, 4 wt.% of dispersant Solsperse 41000, 1 wt.% of photoinitiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide 819 and 4 wt.% of light absorber phosphor Sr5(PO4)3Cl:Eu were mixed in a vacuum stirring tank.

[0099] Step 2.2 Place the above SiC w The mixture with the photosensitive precursor was first dispersed in a vacuum mixer at level 3 for 20 minutes.

[0100] Step 2.3: Place the dispersed mixture into a planetary ball mill with a ball-to-material ratio of 2.5:1 and a ball milling bead size of 4 mm:6 mm:8 mm = 5:3:2. Mill for 7 h at a speed of 250 r / min.

[0101] Step 2.4 Use viscometer to measure the UV-curable SiC obtained by ball milling w -SiBOC ceramic precursor slurry, slurry viscosity at room temperature, shear rate of 100s -1 3.1 Pa·s -1 .

[0102] Step 3: Photocuring of pre-shaped two-dimensional SiC fiber prepreg:

[0103] Step 3.1 Test the UV-curable SiC prepared in step 2 using a digital light processing 3D printer w -The cured thickness of SiBOC ceramic precursor slurry reaches 400mJ / cm 2 The curing depth under the UV radiation dose is 109μm.

[0104] Step 3.2: Cut the two-dimensional plain-weave SiC cloth into a cuboid with a length and width of 250 mm × 150 mm.

[0105] Step 3.3: Flatten the cut two-dimensional SiC fiber cloth on the release film between the rotating shafts, and use a micrometer to adjust the scraper height to control the height difference between the rear scraper and the fiber cloth to 200 μm.

[0106] Step 3.4: Prepare the UV-curable SiC w - SiBOC ceramic precursor slurry was added to the polytetrafluoroethylene cylinder, and then the shaft and UV lamp were turned on. The shaft speed was adjusted to 20 r / min so that the slurry was evenly coated on the fiber cloth. The UV light power was adjusted to 85 mW / cm 2 Realize simultaneous UV pre-curing of slurry coating.

[0107] Replace the fiber cloth and repeat step 3 to pre-solidify multiple cut two-dimensional SiC fiber cloths to meet the thickness requirement of the green blank after stacking, compaction and thermal curing.

[0108] Step 4: Heat curing and shaping the SiC cellulose blank:

[0109] Step 4.1: Use a graphite mold to stack and compact the two-dimensional SiC fiber prepreg prepared in step 3.

[0110] Step 4.2: Place the prepreg laminate and the mold in an oven and heat it to 180°C at a heating rate of 10°C / min. Maintain the temperature for 75 minutes to allow the precursors between the fibers to fully crosslink and solidify, obtaining a SiC cellulose blank with a thickness of 3.4 mm.

[0111] Step 5: Inert atmosphere cracking and forming SiC fiber preform:

[0112] The SiC cellulose blank after heat curing was placed in a vacuum furnace and heated to 1300°C at a heating rate of 1°C / min or 2°C / min under an argon atmosphere of 150 sccm and kept warm for 3 hours. During the heating process, three 2-hour holding sections were set at 250°C, 500°C and 750°C. Finally, the temperature was lowered to 500°C at a rate of 4°C / min and cooled to room temperature with the furnace, so that the SiBOC precursor was fully cracked and evenly coated on the SiC fibers and SiC w , forming a SiC fiber preform;

[0113] Step 6: Preparation of a uniform self-healing modified matrix by reaction melt infiltration:

[0114] The SiC fiber preform was coated with Si powder and encapsulated with graphite paper. The whole preform was then placed in a vacuum furnace at a vacuum degree of 5×10 2 Pa, the temperature is 1550℃, and the reaction melt infiltration is completed after 60 minutes of reaction.

[0115] The density of the prepared SiC / SiC composite material measured by the Archimedean drainage method was 2.73 g / cm 3 , the open porosity is 5.84%. Figure 3 It shows that the self-healing phase and whisker toughening phase introduced into the matrix are dispersed and evenly distributed. Figure 4 BO and BC bonds were detected within the composite matrix, further demonstrating the uniform distribution of the self-healing components within the composite matrix. Tests revealed that the SiC / SiC composite retained 81.22% of its flexural strength after oxidation at 1300°C for 50 hours. The self-healing modified material exhibited excellent resistance to water and oxygen corrosion.

[0116] Example 3

[0117] Step 1SiC w Surface treatment:

[0118] Step 1.1 SiC with a diameter of 600 nm and a length of 10-50 μm w The powder was placed in a graphite crucible and placed in a vacuum heat treatment furnace, and the temperature was raised to 1700℃ at a heating rate of 10℃ / min and kept at that temperature for 2h to improve the SiC w Surface flatness.

[0119] Step 1.2 Heat-treated SiC w The powder was placed in an alumina crucible and placed in a box furnace, and the temperature was raised to 1000°C at a heating rate of 5°C / min and kept at this temperature for 30 min to obtain SiC with a surface coated with a nano-scale SiO2 film. w .

[0120] Step 2: Prepare UV-curable SiC w -SiBOC ceramic precursor slurry:

[0121] Step 2.1 The surface is treated to a mass fraction of 39wt.% SiC w, 25wt.% UV-curable SiBOC ceramic precursor resin, 25wt.% diluent 1,6-hexanediol diacrylate HDDA, 5wt.% dispersant KOS110: silane coupling agent KH550 = 1:1, 1wt.% photoinitiator diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide TPO and 5wt.% light absorber phosphor BaMgAl 10 O 17 :Eu BAM:Eu 2+ Mix in a vacuum mixing tank.

[0122] Step 2.2 Place the above SiC w The mixture with the photosensitive precursor was first dispersed in a vacuum mixer at level 3 speed for 30 minutes.

[0123] Step 2.3: Place the dispersed mixture into a planetary ball mill with a ball-to-material ratio of 3:1 and bead sizes of 4 mm:6 mm:8 mm = 5:3:2. Mill for 8 h at a speed of 300 r / min.

[0124] Step 2.4 Use viscometer to measure the UV-curable SiC obtained by ball milling w -SiBOC ceramic precursor slurry, slurry viscosity at room temperature, shear rate of 100s -1 5.3 Pa·s -1 .

[0125] Step 3: Photocuring of pre-shaped two-dimensional SiC fiber prepreg:

[0126] Step 3.1 Test the UV-curable SiC prepared in step 2 using a digital light processing 3D printer w -The cured thickness of SiBOC ceramic precursor slurry reaches 450mJ / cm 2 The curing depth under the UV radiation dose is 79μm.

[0127] Step 3.2: Cut the two-dimensional satin SiC cloth into a cuboid with a length and width of 250 mm × 150 mm.

[0128] Step 3.3: Flatten the cut two-dimensional SiC fiber cloth on the release film between the rotating shafts, and use a micrometer to adjust the scraper height to control the height difference between the rear scraper and the fiber cloth to 250 μm.

[0129] Step 3.4: Prepare the UV-curable SiC w - SiBOC ceramic precursor slurry was added to the polytetrafluoroethylene cylinder, and then the shaft and UV lamp were turned on. The shaft speed was adjusted to 10 r / min so that the slurry was evenly coated on the fiber cloth. The UV light power was adjusted to 90 mW / cm 2Realize simultaneous UV pre-curing of slurry coating.

[0130] Replace the fiber cloth and repeat step 3 to pre-solidify multiple cut two-dimensional SiC fiber cloths to meet the thickness requirement of the green blank after stacking, compaction and thermal curing.

[0131] Step 4: Heat curing and shaping the SiC cellulose blank:

[0132] Step 4.1: Use a graphite mold to stack and compact the two-dimensional SiC fiber prepreg prepared in step 3.

[0133] Step 4.2: Place the prepreg laminate and the mold in an oven and heat it to 190°C at a heating rate of 10°C / min. Maintain the temperature for 90 minutes to allow the precursors between the fibers to fully crosslink and solidify, obtaining a SiC cellulose blank with a thickness of 5.1 mm.

[0134] Step 5: Inert atmosphere cracking and forming SiC fiber preform:

[0135] The SiC cellulose blank after heat curing was placed in a vacuum furnace and heated to 1400℃ at a heating rate of 1℃ / min or 2℃ / min under 200sccm argon atmosphere and kept at this temperature for 3h. During the heating process, three 2.5h holding sections were set at 300℃, 550℃ and 800℃. Finally, the temperature was lowered to 400℃ at a rate of 5℃ / min and cooled to room temperature with the furnace, so that the SiBOC precursor was fully cracked and evenly coated with SiC fibers and SiC w , forming a SiC fiber preform;

[0136] Step 6: Preparation of a uniform self-healing modified matrix by reaction melt infiltration:

[0137] The SiC fiber preform was coated with Si powder and encapsulated with graphite paper. The whole preform was then placed in a vacuum furnace at a vacuum degree of 5×10 2 Pa, the temperature is 1600℃, and the reaction melt infiltration is completed after 75 minutes of reaction.

[0138] The density of the prepared SiC / SiC composite material measured by the Archimedean drainage method was 2.79 g / cm 3 , the open porosity is 4.91%. Figure 3 It shows that the self-healing phase and whisker toughening phase introduced into the matrix are dispersed and evenly distributed. Figure 4 BO and BC bonds were detected within the composite matrix, further demonstrating the uniform distribution of the self-healing components within the composite matrix. Tests revealed that the SiC / SiC composite retained 81.47% of its flexural strength after oxidation at 1300°C for 50 hours. The self-healing modified material exhibited excellent resistance to water and oxygen corrosion.

[0139] The high-density SiC / SiC composite material with uniformly distributed self-healing components prepared by the above method is characterized in that the introduction of the self-healing modified boron source comes from a SiBOC ceramic precursor that can be cured by ultraviolet light. w -SiBOC precursor slurry is evenly dispersed on the two-dimensional SiC fiber cloth by light curing. w -The UV curing effect of SiBOC ceramic precursor slurry can obtain SiC uniformly distributed on the SiC cloth without changing the thickness of the SiC cloth. w -SiBOC ceramic precursor, which can achieve self-healing component B element and interlayer reinforcement phase SiC without being affected by gravity w The uniform distribution of SiC in the final composite material w , B4C and SiBC are evenly distributed in the matrix, solving the problem that the slurry cannot be retained on the SiC cloth in sufficient quantity; the single crystal SiC w Evenly distributed within the layer after light curing and between layers after thermal curing, and SiC w The SiC fibers are fully covered by the self-healing matrix after RMI, and the high-strength and tough SiC w As the nucleation site of the carbon-silicon reaction, the SiC generated by the reaction can grow in a specific direction, which can not only fill a part of the pores between the fiber bundles and the pores between the fiber cloth layers, but also make up for the problem of low fracture toughness caused by the continuous distribution of the self-healing phase; the porosity of the composite material is less than 8%, and the bending strength retention rate after oxidation at 1300°C for 50 hours is greater than 80%.

Claims

1. A high-density SiC / SiC composite material with uniformly distributed self-healing components, characterized by: Using UV-curable SiBOC ceramic precursor as self-healing modified boron source, SiC w -SiBOC precursor slurry is evenly dispersed on the two-dimensional SiC fiber cloth by light curing to obtain SiC uniformly distributed on the SiC cloth. w -SiBOC ceramic precursor, realizing self-healing component B element and interlayer reinforcement phase SiC w Uniform distribution of SiC in composite materials w , B4C and SiBC are evenly distributed in the SiC matrix after the reaction melt infiltration; the SiC generated by the reaction is along the SiC w The composite material grows in a radial direction and is overlapped and embedded to improve the strength and toughness of the matrix; the porosity of the composite material is less than 8%, The bending strength retention rate after oxidation at 1300℃ for 50h is greater than 80%.

2. A method for preparing a high-density SiC / SiC composite material with uniformly distributed self-healing components according to claim 1, characterized in that Here are the steps: Step 1: UV-curable SiC w -Preparation of SiBOC ceramic precursor slurry: SiBoc with a mass fraction of 25-40 wt.% w , 25-32 wt.% of a photocurable SiBOC ceramic precursor resin, 25-32 wt.% of a diluent, 3-5 wt.% of a dispersant, 1 wt.% of a photoinitiator and 3-5 wt.% of a light absorber are mixed and dispersed, ball milled, and a UV-curable SiC is obtained. w -SiBOC ceramic precursor slurry; Step 2: Photocuring pre-shaped two-dimensional SiC fiber prepreg: The UV-curable SiC obtained in step 1 is w - SiBOC ceramic precursor slurry is evenly coated on SiC fiber cloth, and the UV power is 80-90mW / cm 2 Under light-curing conditions, simultaneous UV pre-curing of the slurry coating is achieved to obtain a light-cured two-dimensional SiC fiber prepreg; Step 3, thermally curing and shaping the SiC cellulose blank: the two-dimensional SiC fiber prepreg obtained by light curing in step 2 is laminated, compacted and shaped, and then placed in an oven for thermal curing to obtain a SiC cellulose blank; Step 4, inert atmosphere cracking SiC fiber preform: placing the heat-cured and shaped SiC cellulose blank in a vacuum furnace, heating it to 1200-1400°C at a heating rate of 1°C / min or 2°C / min in an argon atmosphere of 100-200 sccm and keeping it warm for 3 hours, and setting three 1-3 hour holding sections at 200-300°C, 400-600°C and 700-800°C during the heating process, finally cooling it to 400-600°C at a rate of 2-5°C / min and cooling it to room temperature with the furnace, so that the SiBOC precursor is fully cracked and evenly covers the SiC fiber and SiC w , forming a SiC fiber preform; Step 5: Prepare the self-healing modified matrix by reactive melt infiltration: SiC fiber preform is coated with Si powder and encapsulated with graphite paper, and then the whole is placed in a vacuum furnace at a vacuum degree of 5×10 2 Pa, the temperature is 1500 ℃ ~ 1600 ℃, the reaction melt infiltration is completed after the reaction is carried out for 40 to 80 minutes, and a high-density SiC / SiC composite material with uniform distribution of self-healing components is obtained.

3. The method according to claim 2, wherein: The thickness of the SiC cellulose blank in step 3 is 1 to 6 mm.

4. The method according to claim 2, wherein: The two-dimensional SiC fiber prepreg stack is compacted and shaped using a graphite mold.

5. The method according to claim 2, wherein: The SiC of step 1 w Surface treatment: SiC w The powder is placed in a vacuum heat treatment furnace at a temperature of 1600-1700°C for 1-2 hours to improve the surface smoothness. w The powder is placed in a box furnace, the processing temperature is: 900 ~ 1050 ° C, the processing time is: 30~90min, SiC with nano-scale SiO2 film on the surface is obtained w .

6. The method according to claim 2, wherein: The slurry dispersion: the SiC w The mixture with the photosensitive precursor is first dispersed in a vacuum mixer for 15 to 30 minutes, and then placed in a planetary ball mill for 6 to 8 hours, with a ball-to-material ratio of 3:1 to 2:1 and a rotation speed controlled at 200 to 300 r / min. The viscosity of the obtained slurry is at room temperature and a shear rate of 100s -1 1~6Pa·s -1 .

7. The method according to claim 2, wherein: In the thermal curing process of the SiC cellulose blank in step 2, the prepreg laminate and the mold are placed in an oven and heated to 170-200° C. at a heating rate of 5-10° C. / min, and kept at this temperature for 60-90 minutes to fully crosslink and cure the precursors between the fibers.

8. The method according to claim 2, wherein: The diluent is 1,6-hexanediol diacrylate HDDA; the dispersant is one or more of KOS110, Solsperse41000, Solsperse17000, BYK110, and silane coupling agent KH550; the photoinitiator is one of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide 819 and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide TPO; the light absorber is Sudan red, phosphor BaMgAl 10 O 17 :Eu BAM:Eu 2+ and one or more of Sr5(PO4)3Cl:Eu.

9. A light curing system for two-dimensional SiC fiber prepreg, characterized in that The invention comprises a first main rotating shaft, a first slave rotating shaft, a second main rotating shaft, a second slave rotating shaft, a glass plate, a release film, an ultraviolet curing light source, a polytetrafluoroethylene material cylinder, a bracket, a front scraper and a rear scraper; a release film is provided on the glass plate, one end of the release film is wound on the first main rotating shaft, and the other end of the release film is located on the second main rotating shaft; a first slave rotating shaft and a second slave rotating shaft are respectively provided on both sides of the glass plate, the release film is placed on the glass plate through the two slave rotating shafts, and moves on the glass plate with the first main rotating shaft under the traction of the second main rotating shaft; a polytetrafluoroethylene material cylinder, a bracket and an ultraviolet curing light source are sequentially provided on the glass plate along the moving direction of the release film, and a front scraper and a rear scraper are provided on the bracket; the distance between the front scraper and the release film is longer than the distance between the rear scraper and the release film.

10. A method for using a light-curing system for two-dimensional SiC fiber prepreg, characterized by: During operation, the slurry is placed in a polytetrafluoroethylene cylinder and the two-dimensional SiC fiber is placed on a release film; the release film drives the two-dimensional SiC fiber through the polytetrafluoroethylene cylinder and the slurry is laid on the two-dimensional SiC fiber; the release film drives the two-dimensional SiC fiber through the bracket, and the front scraper and the rear scraper on the bracket evenly coat the slurry on the two-dimensional SiC fiber; then the fiber passes through the ultraviolet curing light source area to cure the two-dimensional SiC fiber coated with the slurry; the distance between the front scraper and the release film, as well as the distance between the rear scraper and the release film, are adjusted, and the difference between the two distances is the thickness of the slurry.

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