High-yield ceramic precursor based on filler activation technology

Abstract

The invention discloses a high-yield ceramic precursor based on a filler activation technology, and belongs to the technical field of ceramic-based composite materials, and the high-yield ceramic precursor is prepared by the following steps: micro-oxidizing the surfaces of carbide ceramic particles by using high-energy ball milling, and grafting hydroxyl as an active group; enabling the ceramic particles grafted with the hydroxyl groups to react with micromolecular monochlorodimethylsilane with carbon-carbon double bonds; washing the ceramic particles for multiple times by using a hydroxyl-free organic solvent, and carrying out vacuum drying treatment; doping the dried ceramic particles into a vinyl ceramic precursor, and carrying out ultra-high-speed shearing dispersion treatment; and curing and cracking the mixed precursor to prepare the high-temperature-resistant ceramic. The high-yield ceramic precursor based on the filler activation technology has extremely high ceramization yield, and the preparation process of the ceramic or ceramic-based composite material prepared by using the high-yield ceramic precursor has the characteristics of short densification period and excellent temperature resistance.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic-based composite materials, in particular to a high-yield ceramic precursor based on filler activation technology. Background Art

[0002] Fiber-reinforced ceramic matrix composites are widely used in aerospace vehicles, nuclear energy and many other fields due to their good temperature resistance, low density and high service reliability. Traditional ceramic matrix composite processes include precursor impregnation pyrolysis (PIP), chemical vapor deposition (CVI) and reactive melt infiltration (RMI). The CVI process achieves material densification through gas-phase small molecule pyrolysis deposition, but is not suitable for thick-walled samples; the PIP process densifies through repeated impregnation-pyrolysis of the precursor, and can freely prepare various shapes of samples, but it often requires 9-16 rounds of repetition, and the precursor utilization rate is low (about 30wt%); the long cycle and high cost of the CVI and PIP processes greatly limit their wide application. Compared with the first two, the RMI process has a relatively short preparation cycle, but the high-temperature metal melt has a large degree of damage to the fiber, which significantly affects the mechanical properties of the material.

[0003] In order to shorten the densification cycle of the PIP process, various precursor modification methods emerge in an endless stream. Chinese patent CN118546168 discloses a high-yield SiBCN precursor, which uses unsaturated double bonds such as vinyl to increase the crosslinking degree of the precursor, thereby greatly improving the ceramic yield, but this precursor can still be further improved by adding inorganic fillers. Chinese patent CN 113788697 discloses a ceramic slurry doped with an inert filler, which uses a vinyl organosilicon precursor and an inert ceramic filler to achieve a higher ceramic yield, but the degree of improvement is limited. Chinese patent CN114014654 discloses an active filler-modified organosilicon precursor, which has a higher ceramic yield. However, the active fillers represented by titanium, aluminum, and silicon have low melting points, resulting in poor high-temperature service capabilities of ceramic-based composites. In addition, in the existing PIP technology, even for filler-modified precursors, 6-9 rounds of impregnation-cracking are still required for densification of ceramic-based composites.

[0004] Filler blending is a very effective means to improve the precursor yield. Rich high-melting-point inert fillers provide effective protection for the high-temperature service capability of ceramic-based composites. However, compared with active fillers, the precursor yield improvement they can provide is very limited. Therefore, it is very necessary to provide a modification technology that can activate high-melting-point inert fillers, so as to obtain high-yield precursors and ceramic / ceramic-based composites with excellent temperature resistance. Summary of the invention

[0005] The object of the present invention is to provide a high-yield ceramic precursor based on filler activation technology to solve the above problems.

[0006] To achieve the above object, the present invention provides a high-yield ceramic precursor based on filler activation technology, and the preparation method comprises:

[0007] (1) blending high melting point inert ceramic particles with deionized water, using high energy ball milling to make the inert ceramic particles react with the deionized water, slightly oxidizing the surface of the ceramic particles and grafting hydroxyl groups, obtaining inert ceramic powder after ball milling, and drying the inert ceramic powder to obtain dried hydroxyl-grafted ceramic powder;

[0008] (2) mixing the dried hydroxy-grafted ceramic powder and monochlorodimethylsilane having an unsaturated double bond in an organic solvent, and dispersing the mixture using a high-speed shear disperser to obtain a dispersed ceramic filler reaction solution;

[0009] (3) passing the dispersed ceramic filler reaction liquid through a nitrogen atmosphere and performing a heating and stirring reaction, and after the reaction is completed, washing it several times with an organic solvent, and vacuum drying the washed ceramic filler to prepare a double bond silane-modified ceramic filler;

[0010] (4) dispersing the double-bond silane-modified ceramic filler dried in step (3) in an organic silicon precursor having a carbon-carbon double bond, adding peroxide as an initiator, and finally preparing an activated ceramic filler-modified precursor;

[0011] (5) solidifying the activated ceramic filler modified precursor, and pyrolyzing the solidified precursor at high temperature to prepare a pyrolyzed ceramic / ceramic matrix composite material.

[0012] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the inert ceramic particles in step (1) are micron-sized or submicron-sized refractory metal carbides, borides and nitrides.

[0013] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the volume ratio of filler to deionized water in step (1) is 1:5-10; the ball milling time is 15h-30h; and the temperature of the dried deionized water is 80°C-110°C.

[0014] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the monochlorodimethylsilane with unsaturated double bonds in step (2) is vinyldimethylchlorosilane or allyldimethylchlorosilane, and the added amount is 10wt% to 40wt% of the filler mass.

[0015] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the rate of high-speed shear dispersion in step (2) is 10000 r / min to 20000 r / min; and the selected organic solvent is n-hexane or diethyl ether.

[0016] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the heating temperature in step (3) is 40° C. to 80° C., and the stirring speed is 1000 r / min to 1600 r / min.

[0017] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the washing solvent used in step (3) is n-hexane, and the temperature of vacuum drying is 40-60°C.

[0018] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the amount of double-bond silane-modified ceramic filler added in step (4) is 10 Vol% to 30 Vol% of the organosilicon precursor with carbon-carbon double bonds, and the high-speed shear dispersion rate is 10,000 r / min to 20,000 r / min; the organosilicon precursor with carbon-carbon double bonds used is polycarbosilane, polysiloxane, polysilazane, polysiliborazane with vinyl or allyl groups.

[0019] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, the peroxide initiator added in step (4) is benzoyl peroxide, diisopropylbenzene peroxide, di-tert-butyl peroxide isopropylbenzene, or tert-butyl peroxide; the added amount is 0.5wt% to 1wt% of the precursor mass.

[0020] Preferably, in the above-mentioned high-yield ceramic precursor based on filler activation technology, in step (5), the pyrolysis heating program is: heating from room temperature to 200°C within 1 hour and keeping warm for 30 minutes; heating from 200°C to 250°C within 30 minutes and keeping warm for 15 minutes; heating from 250°C to 300°C within 30 minutes and keeping warm for 30 minutes; heating from 300°C to 400°C within 1 hour and keeping warm for 1-2 hours; heating from 400°C to 600°C within 3 hours and keeping warm for 1-2 hours; heating from 600°C to 800°C within 2 hours and keeping warm for 1-2 hours; heating from 800°C to the target temperature within 3 hours and keeping warm for 1-2 hours; the target temperature is 900-1100°C.

[0021] The prepared activated ceramic filler modified precursor has a high ceramic yield, and the pyrolyzed ceramic has extremely high sintering activity and can be sintered below 1500°C. At the same time, due to the introduction of high-melting-point refractory metal-based ceramics as modified fillers, the ceramics pyrolyzed from this precursor have excellent temperature resistance.

[0022] Therefore, the present invention adopts a high-yield ceramic precursor based on filler activation technology with the above structure, which has the following beneficial effects:

[0023] (1) In the present invention, the grafted ceramic powder modified organosilicon precursor has an extremely high ceramic yield. Compared with the mass yield of 30wt% to 60wt% of the traditional precursor, the mass yield of this precursor can reach 93wt%. This process greatly reduces the production cost of ceramic / ceramic matrix composite materials and improves the preparation efficiency.

[0024] (2) In the present invention, a high melting point refractory metal compound is used as a grafted modified filler, so that the temperature resistance of the ceramic-based composite material is further improved. Compared with the stable service temperature of the unmodified silicon-based ceramic matrix of about 1500°C, the ceramic precursor prepared in the present invention introduces a refractory metal matrix ceramic with a service temperature of up to 2000°C as a modified phase, which greatly improves the temperature resistance of the cracked ceramic product.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a process flow chart of preparing a vinyl grafted inert filler modified precursor of a high-yield ceramic precursor embodiment based on filler activation technology of the present invention;

[0027] Figure 2 It is an infrared spectrum of ceramic particles before and after activation of an embodiment of a high-yield ceramic precursor based on filler activation technology of the present invention;

[0028] Figure 3 This is a TG-DSC curve of an activated high entropy ceramic powder modified polysilicon borazane precursor according to a high-yield ceramic precursor embodiment of the present invention based on filler activation technology. DETAILED DESCRIPTION

[0029] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0031] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0032] Example 1

[0033] (1) Zirconium boride powder and deionized water were added into a ball mill at a volume ratio of 1:5 and high-energy ball milled for 15 h. The milled powder was dried at 90° C. until it was completely free of moisture.

[0034] (2) The dried zirconium boride powder and vinyldimethylchlorosilane were mixed in n-hexane at a mass ratio of 4:1, and dispersed at a speed of 20000 r / min using high-speed shear dispersion.

[0035] (3) The dispersed liquid was placed in a Schlenk apparatus with nitrogen protection and heated with magnetic stirring, the heating temperature was 40°C, the stirring speed was 1400 r / min, and the reaction time was 24 h. The ceramic powder after the reaction was rinsed with n-hexane four times, and the rinsed ceramic powder was vacuum dried at a temperature of 50°C.

[0036] (4) The grafted zirconium boride and vinyl polycarbosilane are blended in a volume ratio of 7:100 and dispersed by high-speed shear, and 1 wt % of benzoyl peroxide is added as an initiator to obtain an activated zirconium boride-modified polysilicon borazane precursor.

[0037] (5) The precursor is cured at 180°C, and the cured block is cracked at a peak temperature of 1000°C. The cracking process is as follows: heating from room temperature to 200°C within 1 hour and keeping the temperature for 30 minutes; heating from 200°C to 250°C within 30 minutes and keeping the temperature for 15 minutes; heating from 250°C to 300°C within 30 minutes and keeping the temperature for 30 minutes; heating from 300°C to 400°C within 1 hour and keeping the temperature for 1 hour; heating from 400°C to 600°C within 3 hours and keeping the temperature for 1 hour; heating from 600°C to 800°C within 2 hours and keeping the temperature for 1 hour; heating from 800°C to 1000°C within 3 hours and keeping the temperature for 1 hour.

[0038] The active grafted filler modified ceramic precursor prepared in this embodiment has a ceramic mass yield of 83wt% and a volume yield of 37Vol%.

[0039] Example 2

[0040] Example 2 is basically the same as Example 1 (1) to (6), except that:

[0041] The powder added in step (1) is (Ti, Zr, Hf)C high entropy ceramic powder.

[0042] In step (4), the grafted modified high entropy ceramic powder is blended with vinyl polysilicon borazane in a volume ratio of 25:100 and dispersed by high-speed shear, and 1 wt % of isopropylbenzene peroxide is added as an initiator.

[0043] The infrared spectrum analysis of the filler prepared in this example before and after active grafting is as follows Figure 2 The modified ceramic precursor prepared in this example has a ceramic mass yield of 93wt%, a volume yield of 54Vo l%, and a TG-DSC curve as shown in Figure 3 shown.

[0044] Comparative Example 1

[0045] Comparative Example 1 is substantially the same as Example 1 (4) to (6), except that:

[0046] The ceramic powder used in step (4) is unmodified 1 μm zirconium boride ceramic powder, and the precursor is vinyl polysilicon borazane.

[0047] The conventional inert filler-modified ceramic precursor prepared in this embodiment has a ceramic mass yield of 75 wt % and a volume yield of 31 Vol %.

[0048] Comparative Example 2

[0049] Comparative Example 2 is substantially the same as Example 1 (4) to (6), except that:

[0050] In step 4, no ceramic particles are added for modification, and vinyl polysilicon borazane is directly used for curing and cracking.

[0051] The ceramic precursor used in this embodiment has a ceramic mass yield of 62wt% and a volume yield of 25Vol%.

[0052] Table 1: Performance indicators of examples and comparative examples

[0053]

[0054] Therefore, the present invention adopts a high-yield ceramic precursor based on filler activation technology with the above structure, and the grafted ceramic powder modified organic silicon precursor has an extremely high ceramic yield. Compared with the mass yield of 30wt% to 60wt% of the traditional precursor, the mass yield of this precursor can reach 93wt%. This process greatly reduces the production cost of ceramic / ceramic-based composite materials and improves the preparation efficiency. The use of high-melting-point refractory metal compounds as grafted modified fillers further improves the temperature resistance of ceramic-based composite materials. Compared with the stable service temperature of about 1500°C of the unmodified silicon-based ceramic matrix, the ceramic precursor prepared in the present invention introduces a refractory metal matrix ceramic with a service temperature of up to 2000°C as a modified phase, which greatly improves the temperature resistance of the cracked ceramic product.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A high-yield ceramic precursor based on filler activation technology, characterized in that: Made by the following steps: (1) blending high melting point inert ceramic particles with deionized water, using high energy ball milling to make the inert ceramic particles react with the deionized water, slightly oxidizing the surface of the ceramic particles and grafting hydroxyl groups, obtaining inert ceramic powder after ball milling, and drying the inert ceramic powder to obtain dried hydroxyl-grafted ceramic powder; (2) mixing the dried hydroxy-grafted ceramic powder and monochlorodimethylsilane having an unsaturated double bond in an organic solvent, and dispersing the mixture using a high-speed shear disperser to obtain a dispersed ceramic filler reaction solution; (3) passing the dispersed ceramic filler reaction liquid through a nitrogen atmosphere and performing a heating and stirring reaction, and after the reaction is completed, washing it several times with an organic solvent, and vacuum drying the washed ceramic filler to prepare a double bond silane-modified ceramic filler; (4) dispersing the double-bond silane-modified ceramic filler dried in step (3) in an organic silicon precursor having a carbon-carbon double bond, adding peroxide as an initiator, and finally preparing an activated ceramic filler-modified precursor; (5) solidifying the activated ceramic filler modified precursor, and pyrolyzing the solidified precursor at high temperature to prepare a pyrolyzed ceramic / ceramic matrix composite material.

2. A high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: The inert ceramic particles described in step (1) are micron-sized or submicron-sized refractory metal carbides, borides and nitrides.

3. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: Step (1) The volume ratio of filler to deionized water is 1:5-10; the ball milling time is 15h-30h; and the temperature of drying the deionized water is 80°C-110°C.

4. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: In step (2), the monochlorodimethylsilane having unsaturated double bonds is vinyldimethylchlorosilane or allyldimethylchlorosilane, and the added amount is 10wt% to 40wt% of the mass of the filler.

5. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: The speed of high-speed shear dispersion in step (2) is 10000 r / min to 20000 r / min; the selected organic solvent is n-hexane or ether.

6. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: The heating temperature in step (3) is 40° C. to 80° C., and the stirring speed is 1000 r / min to 1600 r / min.

7. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: The washing solvent used in step (3) is n-hexane, and the temperature of vacuum drying is 40-60°C.

8. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: In step (4), the amount of double-bond silane-modified ceramic filler added is 10 Vol% to 30 Vol% of the organic silicon precursor with carbon-carbon double bonds, and the high-speed shear dispersion rate is 10000 r / min to 20000 r / min; the organic silicon precursor with carbon-carbon double bonds used is polycarbosilane, polysiloxane, polysilazane, and polysiliborazane with vinyl or allyl groups.

9. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: The peroxide initiator added in step (4) is benzoyl peroxide, diisopropylbenzene peroxide, di-tert-butyl peroxide isopropylbenzene, or tert-butyl peroxide; the added amount is 0.5 wt% to 1 wt% of the mass of the precursor.

10. The high-yield ceramic precursor based on filler activation technology according to claim 1, characterized in that: In step (5), the pyrolysis temperature program is: heating from room temperature to 200°C within 1 hour and keeping warm for 30 minutes; heating from 200°C to 250°C within 30 minutes and keeping warm for 15 minutes; heating from 250°C to 300°C within 30 minutes and keeping warm for 30 minutes; heating from 300°C to 400°C within 1 hour and keeping warm for 1-2 hours; heating from 400°C to 600°C within 3 hours and keeping warm for 1-2 hours; heating from 600°C to 800°C within 2 hours and keeping warm for 1-2 hours; heating from 800°C to the target temperature within 3 hours and keeping warm for 1-2 hours; the target temperature is 900-1100°C.

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