Rapidly densified ceramic-based composite material slurry as well as preparation method and application thereof

Abstract

The invention discloses quickly densified ceramic matrix composite slurry as well as a preparation method and application thereof, and belongs to the technical field of preparation of composite materials. The slurry comprises slurry powder and a slurry solvent; the slurry powder is prepared from the following components in parts by weight: 25 to 35 parts of polycarbosilane, 10 to 15 parts of SiC whiskers, 40 to 50 parts of SiC ceramic powder, 0.5 to 3 parts of calcium fluoride, 0.5 to 2 parts of lanthanum oxide and 10 to 25 parts of boron-containing powder; the slurry solvent comprises the following components in parts by weight: 60-70 parts of ethanol, 20-25 parts of a polyurethane binder, 1-10 parts of a dispersing agent and 1-10 parts of a thickening agent. According to the method, the slurry is coated and permeated into the blank ceramic-based composite material, so that rapid densification of the ceramic-based composite material can be realized, the internal porosity of the ceramic-based composite material is reduced, the preparation of the ceramic-based composite material is accelerated, and the toughness and fracture resistance of the prepared ceramic-based composite material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and particularly relates to a rapidly densifying ceramic matrix composite material slurry, a preparation method thereof, and an application thereof. Background Art

[0002] Due to excellent properties such as high-temperature mechanical properties, low density, corrosion resistance, and thermal shock resistance, ceramic matrix composites have broad application prospects in the fields of aerospace, energy engineering, national defense industry, and high-end manufacturing. Although traditional bulk ceramic materials have excellent high-temperature stability and wear resistance, they generally have disadvantages such as high brittleness and poor heat shock resistance, which limit their application in engineering structural components that need to withstand complex loads or thermal stresses. To overcome this shortcoming, researchers have proposed to significantly improve the toughness and fracture resistance of ceramic materials by introducing fiber reinforcement phases into the ceramic matrix. Such fiber-reinforced ceramic matrix composites have greatly expanded the application boundaries of ceramics.

[0003] However, traditional ceramic matrix composite material preparation technologies (such as PIP, CVI, MI) have defects such as long preparation cycles and poor material densification improvement effects, resulting in poor preparation efficiency of ceramic matrix composites and severely restricting the improvement of the engineering application level of ceramic matrix composites. Taking the PIP preparation method as an example, its core steps include ceramic precursor infiltration, curing, and pyrolysis, and usually need to be iterated repeatedly many times to reach the required density and strength. Each cycle takes a long time (ranging from several days to more than ten days), making it difficult to meet the requirements of industrial mass production. In addition, significant volume shrinkage (usually up to 30%-50%) occurs during the pyrolysis of polymer ceramic precursors, resulting in the formation of a large number of microcracks or local damage inside the ceramic matrix, and the performance attenuation of fibers caused by frequent thermal shock impacts also restricts the performance improvement of ceramic matrix composites. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a rapidly densifying ceramic matrix composite material slurry, a preparation method thereof, and an application thereof, so as to solve the problems of long preparation cycles of existing ceramic matrix composite material preparation technologies, poor material densification improvement effects, and low preparation efficiency of ceramic matrix composites caused by the long cycle required for densification.

[0005] The technical solution of the present invention for solving the above technical problems is as follows:

[0006] A rapidly densifying ceramic matrix composite material slurry, comprising slurry powder and slurry solvent;

[0007] The slurry powder comprises the following components in parts by weight:

[0008] 25-35 parts of polycarbosilane, 10-15 parts of SiC whiskers, 40-50 parts of SiC ceramic powder, 0.5-3 parts of calcium fluoride, 0.5-2 parts of lanthanum oxide, and 10-25 parts of boron-containing element powder;

[0009] The slurry solvent includes the following components in parts by weight:

[0010] 60-70 parts of ethanol, 20-25 parts of polyurethane binder, 1-10 parts of dispersant, and 1-10 parts of thickener.

[0011] The beneficial effects of the present invention are as follows: The present invention provides a slurry for accelerating the densification of ceramic matrix composites. By coating and infiltrating the slurry into the interior of the green ceramic matrix composites, rapid densification of the ceramic matrix composites can be achieved, the porosity inside the ceramic matrix composites can be reduced, and the preparation of the ceramic matrix composites can be accelerated.

[0012] Furthermore, the powder components include the following components in parts by weight:

[0013] 25-30 parts of polycarbosilane, 12-15 parts of SiC whiskers, 42-47 parts of SiC ceramic powder, 1-3 parts of calcium fluoride, 1-2 parts of lanthanum oxide, and 12-20 parts of boron-containing element powder;

[0014] The solvent includes the following components in parts by weight:

[0015] 63-67 parts of ethanol, 22-25 parts of polyurethane binder, 3-7 parts of dispersant, and 3-7 parts of thickener.

[0016] Preferably, the powder components include the following components in parts by weight:

[0017] 25 parts of polycarbosilane, 15 parts of SiC whiskers, 45 parts of SiC ceramic powder, 2 parts of calcium fluoride, 1 part of lanthanum oxide, and 15 parts of boron-containing element powder;

[0018] The solvent includes the following components in parts by weight:

[0019] 65 parts of ethanol, 25 parts of polyurethane binder, 5 parts of dispersant, and 5 parts of thickener.

[0020] Furthermore, the boron-containing element powder is B 4 C or BN; the dispersant is PVP; the thickener is silicon nitride or acrylate.

[0021] Furthermore, the mass ratio of the slurry powder to the slurry solvent in the ceramic matrix composite slurry is (1-3):1, and the viscosity is 500-1500 mPa·s.

[0022] Preferably, the mass ratio of the slurry powder to the slurry solvent in the ceramic matrix composite slurry is 2:1.

[0023] Further, the whisker length of the SiC whiskers is 10 - 20 μm, the diameter is 0.1 - 0.2 μm, and the aspect ratio is 100:1 - 200:1.

[0024] Preferably, the whisker length of the SiC whiskers is 15 μm, the diameter is 0.1 μm, and the aspect ratio is 150:1.

[0025] Further, the SiC whiskers are modified through the following steps:

[0026] First, the SiC whiskers are impregnated successively in a hydrofluoric acid solution and a nitric acid solution, filtered and dried, then impregnated in a silane coupling agent solution, and after filtration and drying, heat treatment is carried out at high temperature to complete the modification.

[0027] Further, the mass concentration of the hydrofluoric acid solution is 5 - 20%, the mass concentration of the nitric acid solution is 5 - 20%, the concentration of the silane coupling agent solution is 1 - 10 g / L, and the silane coupling agent is KH-550;

[0028] The impregnation treatment time in the hydrofluoric acid solution is 20 - 40 min, the impregnation treatment time in the nitric acid solution is 30 - 90 min, and the impregnation treatment time in the silane coupling agent solution is 3 - 5 h;

[0029] The conditions for high-temperature heat treatment are: first, the temperature is raised at a heating rate of 3 - 7 °C / min to 500 - 700 °C, held for 30 - 90 min, then the temperature is raised at a heating rate of 8 - 12 °C / min to 1400 - 1600 °C, held for 2 - 4 h, and finally cooled naturally to room temperature.

[0030] The beneficial effects of adopting the above further technical solutions are as follows: Through hydrofluoric acid modification and silane coupling agent modification, the present invention enhances the dispersibility and wettability of SiC whiskers in the solution, avoids agglomeration in the solution to form large particle agglomerates, and effectively ensures rapid densification during the densification processing of the ceramic matrix composite material by the slurry.

[0031] Preferably, the mass concentration of the hydrofluoric acid solution is 10%, the mass concentration of the nitric acid solution is 10%, the concentration of the silane coupling agent solution is 5 g / L, and the silane coupling agent is KH-550;

[0032] The impregnation treatment time in the hydrofluoric acid solution is 30 min, the impregnation treatment time in the nitric acid solution is 60 min, and the impregnation treatment time in the silane coupling agent solution is 4 h;

[0033] The conditions for high-temperature heat treatment are: first, the temperature is raised at a heating rate of 5 °C / min to 600 °C, held for 30 - 90 min, then the temperature is raised at a heating rate of 10 °C / min to 1500 °C, held for 3 h, and finally cooled naturally to room temperature.

[0034] Furthermore, the particle size of the SiC ceramic powder is 0.1 - 1 μm, and D50 ≈ 0.5 μm.

[0035] The method for preparing the above-mentioned rapidly densified ceramic matrix composite material slurry includes the following steps:

[0036] First, mix the slurry powder for ball milling, then uniformly mix the ball-milled slurry powder with the slurry solvent, and finally perform vacuum degassing treatment to obtain it.

[0037] Furthermore, the rotation speed of the ball milling is 200 - 400 rpm, and the time is 8 - 12 h; the vacuum degree of the vacuum degassing treatment is -0.08 to -0.1 MPa, and the time is 15 - 30 min.

[0038] The application of the above-mentioned rapidly densified ceramic matrix composite material slurry in ceramic densification processing.

[0039] A method for ceramic densification processing based on the above-mentioned rapidly densified ceramic matrix composite material slurry includes the following steps:

[0040] First, coat the above-mentioned rapidly densified ceramic matrix composite material slurry on the surface of the ceramic composite material and infiltrate it into the material interior, then perform drying and curing, and finally perform high-temperature sintering treatment.

[0041] Furthermore, the temperature of the drying and curing is 200 - 300 °C, and the time is 20 - 30 h;

[0042] The conditions for the high-temperature sintering treatment are: first, heat up at a heating rate of 1 - 3 °C / min to 100 - 300 °C, then heat up at a heating rate of 1 - 5 °C / min to 1000 - 1400 °C, hold for 1 - 3 h, then heat up at a heating rate of 2 - 3 °C / min to 1500 - 1700 °C, hold for 1 - 3 h, and finally cool down naturally or at a cooling rate of 1 - 3 °C / min to room temperature.

[0043] The present invention has the following beneficial effects:

[0044] The present invention provides a slurry for rapid densification of ceramic matrix composites and a preparation method thereof. By coating and infiltrating the slurry into the interior of the green ceramic matrix composite material, rapid densification of the ceramic matrix composite material can be achieved, the porosity inside the ceramic matrix composite material can be reduced, and the preparation of the ceramic matrix composite material can be accelerated; by introducing modified SiC whiskers, on the one hand, the rapid densification effect of the slurry in the processing of the ceramic matrix composite material is promoted, and on the other hand, the toughness and fracture resistance of the obtained ceramic matrix composite material are improved. Description of the Drawings

[0045] Figure 1 It is a columnar diagram of density measurement of different samples in the test example;

[0046] Figure 2 It is a bar chart for measuring the flexural strength of different samples in the test examples. Detailed implementation manners

[0047] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. For those conditions not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0048] Example 1:

[0049] A method for preparing a rapidly densified ceramic matrix composite slurry, comprising the following steps:

[0050] (1) Raw material preparation

[0051] Weigh each powder component according to the following parts by weight: 25 parts of PCS, 15 parts of SiC whiskers (aspect ratio 150:1, length 15 μm, diameter 0.1 μm), 45 parts of SiC ceramic powder (particle size 0.1 - 1 μm, D50 ≈ 0.5 μm, purity ≥ 99%), 2 parts of calcium fluoride (purity ≥ 99%), 1 part of lanthanum oxide (purity ≥ 99%) and B 4 C 15 parts.

[0052] Among them, the SiC whiskers are modified by the following method:

[0053] First, take 5 g of SiC whiskers and add them to 100 mL of 10 wt% HF solution, ultrasonically clean for 30 min, filter and then rinse 4 times with deionized water until the solution pH is 7;

[0054] Then, place the SiC whiskers treated in the previous step in 100 mL of 10 wt% HNO 3 solution, stir at 300 rpm for 1 h, filter and rinse 4 times, and dry in a vacuum drying oven at 80 °C for 6 h;

[0055] Next, add the SiC whiskers treated in the previous step to a KH-500 ethanol solution with a concentration of 0.5 g / L, ultrasonically disperse for 30 min, then stir at 50 °C for 4 h, filter and rinse 3 times with deionized water, and dry in a vacuum drying oven at 80 °C for 6 h;

[0056] Finally, the SiC whiskers processed in the previous step are subjected to high-temperature heat treatment in a vacuum furnace. The conditions for high-temperature heat treatment are as follows: under an argon flow rate of 300 mL / min, first heat up to 600 °C at a heating rate of 5 °C / min, hold for 1 h, then continue to heat up to 1600 °C at a heating rate of 10 °C / min, hold for 4 h, and finally cool naturally to room temperature, and take out the SiC whiskers.

[0057] (2) Solvent preparation

[0058] Weigh the solvent components according to the following mass percentages: 65% ethanol, 25% polyurethane binder, 5% dispersant (PVP), and 5% silicon nitride.

[0059] (3) Slurry preparation

[0060] First, mix ethanol and PVP and stir until the dispersant is completely dissolved. Then add the powder components, polyurethane binder, and silicon nitride, and stir in a ball mill at a speed of 300 rpm for 5 h to ensure that the powder is evenly dispersed, obtaining a uniform slurry without bubbles. The mass ratio of the total slurry powder to the total slurry solvent in the slurry is 2:1. Use a rotational viscometer to test the viscosity of the slurry, and the obtained viscosity is 784 mPa·s.

[0061] (4) Degassing treatment

[0062] Place the slurry obtained in step (3) in a vacuum degassing device, set the vacuum degree to -0.08 MPa, and the degassing time to 30 min to obtain a rapidly densified ceramic matrix composite slurry.

[0063] Based on the above rapidly densified ceramic matrix composite slurry, a method for densifying the ceramic matrix composite includes the following steps:

[0064] (5) Matrix treatment

[0065] Select a C / SiC blank material with a density of 1.0 g / cm 3 and perform ultrasonic cleaning, and dry it at 120 °C for 2 h to remove moisture.

[0066] (6) Infiltrating the slurry

[0067] Using the spraying process, evenly coat the slurry obtained in step (4) on the surface of the C / SiC blank material to ensure that the material surface is evenly covered.

[0068] (7) Vacuum filtration densification

[0069] Place the coated blank material in a vacuum filtration device, set the negative pressure to -0.05 MPa, and hold for 10 min to allow the slurry to fully infiltrate the pores of the material.

[0070] Repeat the suction filtration process in steps (6) to (7) three times, and then dry in an oven at 100 °C for 2 h to remove the residual solvent.

[0071] (8) Curing and sintering

[0072] Put the densified material into an argon atmosphere furnace, set the heating rate at 2 °C / min, cure at 400 °C for 2 h, then continue to heat up to 1600 °C, hold for 3 h, and finally cool naturally to room temperature in the furnace to obtain the densified ceramic matrix composite.

[0073] Example 2:

[0074] A method for preparing a rapidly densified ceramic matrix composite slurry, comprising the following steps:

[0075] (1) Raw material preparation

[0076] Weigh each powder component according to the following parts by weight: 25 parts of PCS, 15 parts of SiC whiskers (aspect ratio 200:1, length 20 μm, diameter 0.1 μm), 50 parts of SiC ceramic powder (particle size 0.1 - 1 μm, D50 ≈ 0.5 μm, purity ≥ 99%), 3 parts of calcium fluoride (purity ≥ 99%), 1.5 parts of lanthanum oxide (purity ≥ 99%) and 4 20 parts of BC.

[0077] Among them, the SiC whiskers are modified by the following method:

[0078] First, take 5 g of SiC whiskers and add them to 100 mL of 10 wt% HF solution, ultrasonically clean for 30 min, filter and rinse 4 times with deionized water until the solution pH is 7;

[0079] Then, place the SiC whiskers treated in the previous step in 100 mL of 10 wt% HNO 3 solution, stir at 300 rpm for 1 h, filter and rinse 4 times, and dry in a vacuum drying oven at 80 °C for 6 h;

[0080] Next, add the SiC whiskers treated in the previous step to a KH-500 ethanol solution with a concentration of 0.5 g / L, ultrasonically disperse for 30 min, stir at 50 °C for 4 h, filter and rinse 3 times with deionized water, and dry in a vacuum drying oven at 80 °C for 6 h;

[0081] Finally, the SiC whiskers processed in the previous step are subjected to high-temperature heat treatment in a vacuum furnace. The conditions for high-temperature heat treatment are as follows: under an argon flow rate of 300 mL / min, first heat up to 600 °C at a heating rate of 5 °C / min, hold for 1 h, then continue to heat up to 1600 °C at a heating rate of 10 °C / min, hold for 4 h, and finally cool naturally to room temperature, and take out the SiC whiskers.

[0082] (2) Solvent preparation

[0083] Weigh the solvent components according to the following mass percentages: ethanol 65%, polyurethane binder 25%, dispersant (PVP) 5%, and silicon nitride 5%.

[0084] (3) Slurry preparation

[0085] First, mix ethanol and PVP and stir until the dispersant is completely dissolved. Then add the powder components, polyurethane binder, and silicon nitride, and stir in a ball mill at a speed of 300 rpm for 5 h to ensure that the powder is evenly dispersed and obtain a uniform slurry without bubbles. Use a rotational viscometer to test the viscosity of the slurry, and the obtained viscosity is 816 mPa·s.

[0086] (4) Degassing treatment

[0087] Place the slurry obtained in step (3) in a vacuum degassing device, set the vacuum degree to -0.08 MPa, and the degassing time to 30 min to obtain a rapidly densified ceramic matrix composite slurry.

[0088] Based on the above-mentioned rapidly densified ceramic matrix composite slurry, a densification preparation method for ceramic matrix composites includes the following steps:

[0089] (5) Matrix treatment

[0090] Select a C / SiC blank material with a density of 1.0 g / cm 3 , clean it by ultrasonic wave, and dry it at 120 °C for 2 h to remove moisture.

[0091] (6) Infiltrate the slurry

[0092] Use the spraying process to evenly coat the slurry obtained in step (4) on the surface of the C / SiC blank material to ensure that the material surface is evenly covered.

[0093] (7) Vacuum filtration densification

[0094] Place the coated blank material in a vacuum filtration device, set the negative pressure to -0.05 MPa, and keep it for 10 min to make the slurry fully infiltrate into the material pores.

[0095] Repeat the suction filtration process from step (6) to step (7) three times, and then dry in an oven at 100 °C for 2 h to remove the residual solvent.

[0096] (8) Curing and sintering

[0097] Put the densified material into an argon atmosphere furnace, set the heating rate to 2 °C / min, cure at 400 °C for 2 h, then continue to heat up to 1600 °C, keep the temperature for 3 h, and finally cool naturally to room temperature with the furnace to obtain the densified ceramic matrix composite.

[0098] Example 3:

[0099] A method for preparing a fast-densifying ceramic matrix composite slurry, comprising the following steps:

[0100] (1) Raw material preparation

[0101] Weigh each powder component according to the following weight parts: 25 parts of PCS, 12.5 parts of SiC whiskers (aspect ratio of 200:1, length of 20 μm, diameter of 0.1 μm), 40 parts of SiC ceramic powder (particle size of 0.1 - 1 μm, D50 ≈ 0.5 μm, purity ≥ 99%), 1 part of calcium fluoride (purity ≥ 99%), 0.5 part of lanthanum oxide (purity ≥ 99%) and 4 10 parts of B

[0102] Among them, the SiC whiskers are modified by the following method:

[0103] First, take 5 g of SiC whiskers and add them to 100 mL of 10 wt% HF solution, ultrasonically clean for 30 min, filter and then rinse 4 times with deionized water until the solution pH is 7;

[0104] Then, place the SiC whiskers treated in the previous step in 100 mL of 10 wt% HNO 3 solution, stir at 300 rpm for 1 h, filter and rinse 4 times, and dry in a vacuum drying oven at 80 °C for 6 h;

[0105] Next, add the SiC whiskers treated in the previous step to a KH-500 ethanol solution with a concentration of 0.5 g / L, ultrasonically disperse for 30 min, then stir at 50 °C for 4 h, filter and rinse 3 times with deionized water, and dry in a vacuum drying oven at 80 °C for 6 h;

[0106] Finally, the SiC whiskers processed in the previous step are subjected to high-temperature heat treatment in a vacuum furnace. The conditions for high-temperature heat treatment are as follows: in an atmosphere with an argon flow rate of 300 mL / min, first heat up to 600 °C at a heating rate of 5 °C / min, hold for 1 h, then continue to heat up to 1600 °C at a heating rate of 10 °C / min, hold for 4 h, and finally cool naturally to room temperature, and take out the SiC whiskers.

[0107] (2) Solvent preparation

[0108] Weigh the solvent components according to the following mass percentages: 65% ethanol, 25% polyurethane binder, 5% dispersant (PVP), and 5% silicon nitride.

[0109] (3) Slurry preparation

[0110] First, mix ethanol and PVP and stir until the dispersant is completely dissolved. Then add the powder components, polyurethane binder, and silicon nitride, and stir in a ball mill at a speed of 300 rpm for 5 h to ensure that the powder is evenly dispersed, and obtain a uniform slurry without bubbles. Use a rotational viscometer to test the viscosity of the slurry, and the obtained viscosity is 699 mPa·s.

[0111] (4) Degassing treatment

[0112] Place the slurry obtained in step (3) in a vacuum degassing device, set the vacuum degree to -0.08 MPa, and the degassing time to 30 min to obtain a rapidly densified ceramic matrix composite slurry.

[0113] Based on the above rapidly densified ceramic matrix composite slurry, a method for densifying the ceramic matrix composite includes the following steps:

[0114] (5) Matrix treatment

[0115] Select a C / SiC blank material with a density of 1.0 g / cm 3 Perform ultrasonic cleaning and dry at 120 °C for 2 h to remove moisture.

[0116] (6) Infiltrate the slurry

[0117] Using the spraying process, evenly coat the slurry obtained in step (4) on the surface of the C / SiC blank material to ensure uniform coverage of the material surface.

[0118] (7) Vacuum filtration densification

[0119] Place the coated blank material in a vacuum filtration device, set the negative pressure to -0.05 MPa, and keep it for 10 min to allow the slurry to fully infiltrate the pores of the material.

[0120] Repeat the suction filtration process in steps (6) to (7) three times, and then dry in an oven at 100 °C for 2 h to remove the residual solvent.

[0121] (8) Curing and sintering

[0122] Put the material after densification treatment into an argon atmosphere furnace, set the heating rate to 2 °C / min, cure at 400 °C for 2 h, then continue to heat up to 1600 °C, keep the temperature for 3 h, and finally cool naturally to room temperature in the furnace to obtain the densified ceramic matrix composite material.

[0123] Comparative example 1:

[0124] A preparation method of a rapidly densified ceramic matrix composite material slurry, comprising the following steps:

[0125] The preparation method is the same as that of Example 1, except that the SiC whiskers in step (1) of this comparative example are not modified, and the remaining steps remain unchanged.

[0126] The densification preparation method of the ceramic matrix composite material based on the above rapidly densified ceramic matrix composite material slurry is the same as that of Example 1.

[0127] Comparative example 2:

[0128] A preparation method of a rapidly densified ceramic matrix composite material slurry, comprising the following steps:

[0129] The preparation method is the same as that of Example 1, except that the aspect ratio of the SiC whiskers in step (1) of this comparative example is changed to 50:1, and the remaining steps remain unchanged.

[0130] The densification preparation method of the ceramic matrix composite material based on the above rapidly densified ceramic matrix composite material slurry is the same as that of Example 1.

[0131] Comparative example 3:

[0132] A preparation method of a rapidly densified ceramic matrix composite material slurry, comprising the following steps:

[0133] The preparation method is the same as that of Example 1, except that the aspect ratio of the SiC whiskers in step (1) of this comparative example is changed to 250:1, and the remaining steps remain unchanged.

[0134] The densification preparation method of the ceramic matrix composite material based on the above rapidly densified ceramic matrix composite material slurry is the same as that of Example 1.

[0135] Comparative example 4:

[0136] A preparation method of a rapidly densified ceramic matrix composite material slurry, comprising the following steps:

[0137] The preparation method is the same as that of Example 1, except that in step (1) of this comparative example, the weight portion of B 4 C is changed to 5 parts, and the remaining steps remain unchanged.

[0138] The densification preparation method of the ceramic matrix composite material based on the above-mentioned rapidly densifying ceramic matrix composite material slurry is the same as that of Example 1.

[0139] Comparative Example 5:

[0140] A preparation method of a rapidly densifying ceramic matrix composite material slurry, comprising the following steps:

[0141] The preparation method is the same as that of Example 1, except that in step (1) of this comparative example, B 4 C is not added to the powder component, and the remaining steps remain unchanged.

[0142] The densification preparation method of the ceramic matrix composite material based on the above-mentioned rapidly densifying ceramic matrix composite material slurry is the same as that of Example 1.

[0143] Comparative Example 6:

[0144] A preparation method of a rapidly densifying ceramic matrix composite material slurry, comprising the following steps:

[0145] The preparation method is the same as that of Example 1, except that in step (1) of this comparative example, lanthanum oxide is not added to the powder component, and the remaining steps remain unchanged.

[0146] The densification preparation method of the ceramic matrix composite material based on the above-mentioned rapidly densifying ceramic matrix composite material slurry is the same as that of Example 1.

[0147] Test Example:

[0148] Take the ceramic matrix composite materials prepared in Examples 1-3 and Comparative Examples 1-6, and measure their densities at room temperature of 22 °C, humidity of 31%, and atmospheric pressure of 99 kPa. The experimental results are as Figure 1 shown.

[0149] The results show that the ceramic matrix composites prepared in Examples 1-3 have little difference and all have good density, proving the successful preparation of dense ceramic matrix composites. In Comparative Example 1, since the SiC whiskers were not modified, the dispersibility and wettability of the SiC whiskers in the solution were insufficient, and they were prone to agglomeration, forming large particle agglomerates instead of uniformly distributed whiskers. Therefore, the density of the ceramic matrix composite decreased significantly. The densities of the ceramic matrix composites of Example 1, Comparative Example 4, and Comparative Example 5 decreased in turn. The main reason is that the proportion of boron carbide as a sintering aid decreased in turn. Boron carbide and SiC or SiC whiskers have good chemical compatibility and can form a B-Si-C eutectic or reaction interface at high temperature, significantly reducing the sintering temperature and promoting densification. From Example 1 and Comparative Example 6, it can be seen that lanthanum oxide can cause an increase in the density of the ceramic matrix composite. The main reason is that lanthanum oxide can enhance the formation of the liquid phase during sintering and accelerate densification.

[0150] The ceramic matrix composites prepared in Examples 1-3 and Comparative Examples 1-6 were taken, and the flexural strength was measured using an Instron 8801 electro-hydraulic servo fatigue test system at room temperature of 20 °C, humidity of 32%, and atmospheric pressure of 99 kPa. The experimental results are as Figure 2 shown.

[0151] The results show that the difference in flexural strength among Examples 1-3 is small, and all meet the production standards of ceramic matrix composites. For the ceramic matrix composite prepared in Comparative Example 2, due to the relatively low aspect ratio of the selected silicon carbide, its flexural strength decreased significantly without significant change in the material density. The main reason is that although the SiC whiskers with a low aspect ratio have good dispersibility, their enhancement effect on fracture toughness and flexural strength in the ceramic matrix composite is limited, and it is difficult to effectively hinder the propagation of cracks.

[0152] The flexural strength of the ceramic matrix composite prepared in Comparative Example 3 is close to that of Examples 1-3. The main reason is that the aspect ratio of the whiskers is relatively high, significantly enhancing the pull-out effect. When the crack propagates to the area where the SiC whiskers are located, the interfacial bonding force is moderate, so that the whiskers do not break directly but are gradually pulled out from the matrix. During this process, it is necessary to overcome the interfacial friction force and adhesion force, consuming additional fracture energy, thereby effectively improving the flexural strength of the material.

[0153] The flexural strength of Comparative Example 5 decreased significantly. The main reason is that boron carbide was lacking in the slurry, resulting in poor wettability and impregnation on the carbon fiber framework, and it was difficult to form a dense interfacial bonding layer. During the high-temperature sintering process, the poor interfacial bonding aggravated the oxidative damage of the carbon fiber, resulting in a significant decrease in the mechanical properties of the composite material, manifested as a significant attenuation of the flexural strength.

[0154] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fast densification ceramic matrix composite material slurry, characterized in that: including slurry powder and slurry solvent; The slurry powder comprises the following components in parts by weight: 25-35 parts of polycarbosilane, 10-15 parts of SiC whiskers, 40-50 parts of SiC ceramic powder, 0.5-3 parts of calcium fluoride, 0.5-2 parts of lanthanum oxide and 10-25 parts of boron-containing powder; The slurry solvent comprises the following components in parts by weight: 60-70 parts of ethanol, 20-25 parts of polyurethane binder, 1-10 parts of dispersant and 1-10 parts of thickener.

2. The rapid densification ceramic-based composite material slurry according to claim 1, characterized in that: The mass ratio of the slurry powder to the slurry solvent in the ceramic-based composite material slurry is (1-3):1, and the viscosity is 500-1500 mPa·s.

3. The rapid densification ceramic-based composite material slurry according to claim 1, characterized in that: The SiC whisker has a whisker length of 10-20 μm, a diameter of 0.1-0.2 μm, and an aspect ratio of 100:1-200:

1.

4. The rapid densification ceramic-based composite material slurry according to claim 1 or 3, characterized in that: The SiC whiskers are modified by the following steps: The SiC whisker is first immersed in a hydrofluoric acid solution and a nitric acid solution in sequence, filtered and dried, and then immersed in a silane coupling agent solution, filtered and dried, and then subjected to high-temperature heat treatment to complete the modification.

5. The rapid densification ceramic-based composite material slurry according to claim 4, characterized in that: The mass concentration of the hydrofluoric acid solution is 5-20%, the mass concentration of the nitric acid solution is 5-20%, the concentration of the silane coupling agent solution is 1-10 g / L, and the silane coupling agent is KH-550; The immersion time in the hydrofluoric acid solution is 20-40 minutes, the immersion time in the nitric acid solution is 30-90 minutes, and the immersion time in the silane coupling agent solution is 3-5 hours; The conditions of high temperature heat treatment are: first increase the temperature to 500-700°C at a heating rate of 3-7°C / min, keep warm for 30-90min, then increase the temperature to 1400-1600°C at a heating rate of 8-12°C / min, keep warm for 2-4h, and finally cool naturally to room temperature.

6. The method for preparing the rapid densification ceramic-based composite material slurry according to any one of claims 1 to 5, characterized in that: The following steps are involved: The slurry powder is first mixed and ball-milled, and then the ball-milled slurry powder is evenly mixed with a slurry solvent, and finally vacuum degassing is performed to obtain the product.

7. The method for preparing a rapid densification ceramic-based composite material slurry according to claim 6, characterized in that: The rotation speed of the ball mill is 200-400 rpm, and the time is 8-12 hours; the vacuum degree of the vacuum degassing treatment is -0.08 to -0.1 MPa, and the time is 15-30 minutes.

8. Use of the rapid densification ceramic-based composite material slurry according to any one of claims 1 to 5 in ceramic densification processing.

9. A method for ceramic densification processing based on the rapid densification ceramic-based composite material slurry according to any one of claims 1 to 5, characterized in that: The following steps are involved: The rapid densification ceramic-based composite material slurry according to any one of claims 1 to 5 is firstly coated on the surface of the ceramic composite material and penetrated into the interior of the material, then dried and solidified, and finally subjected to high-temperature sintering treatment.

10. The method for ceramic densification processing based on rapid densification ceramic matrix composite material slurry according to claim 9, characterized in that: The drying and curing temperature is 200-300°C and the time is 20-30h; The conditions of the high temperature sintering treatment are: first increase the temperature to 100-300°C at a heating rate of 1-3°C / min, then increase the temperature to 1000-1400°C at a heating rate of 1-5°C / min, keep warm for 1-3h, then increase the temperature to 1500-1700°C at a heating rate of 2-3°C / min, keep warm for 1-3h, and finally cool down naturally or cool down to room temperature at a cooling rate of 1-3°C / min.

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