A zr / si composite ceramic precursor based on active alkenyl side group-containing zirconium source and a preparation method thereof

Abstract

This invention belongs to the field of ceramic materials technology, specifically relating to a Zr / Si multiphase ceramic precursor based on a zirconium source with active alkenyl side groups and its preparation method. The method includes: reacting zirconium n-propoxide with an unsaturated carboxylic acid in a solution system to obtain an organozirconium monomer with unsaturated carboxylic acid and hydroxyl side groups; subjecting the monomer to dehydration condensation under acidic conditions to obtain an organozirconium compound, which serves as the zirconium source in the multiphase ceramic precursor; and mixing the zirconium source with vinyl hydrogenated polycarbosilane (VHPCS) and vinyl hydrogenated polysiloxane (VHPSO) in solution to obtain the Zr / Si multiphase ceramic precursor. The Zr / Si multiphase ceramic precursor preparation process of this invention is simple, has good solubility, a flexible and adjustable zirconium-silicon ratio, and high curing and ceramic yield, meeting the performance requirements of aerospace materials.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a Zr / Si composite ceramic precursor based on a zirconium source containing active alkenyl side groups and its preparation method. Background Technology

[0002] Zirconium / silicon (Zr / Si) multiphase ceramics are a class of high-temperature structural materials with excellent high-temperature resistance, thermal shock resistance, and oxidation corrosion resistance, showing significant application prospects in aerospace thermal protection systems and ultra-high-temperature engine components. Precursor conversion is an important method for preparing ceramic materials through the pyrolysis reaction of organic-inorganic precursors. It offers advantages such as designable composition, low processing temperature, and ease of achieving near-net-shape forming of complex components, making it particularly suitable for the preparation of multi-component multiphase ceramics. Currently, precursors commonly used to prepare Zr / Si systems mainly include zirconium and silicon-modified organic polymers or organic-inorganic hybrid molecules, which can be converted into the target ceramic through high-temperature pyrolysis in an inert or controlled atmosphere.

[0003] Chinese patent CN110357632A discloses a ZrC / SiC multiphase ceramic precursor and its preparation method. The precursor is prepared by reacting nonpolar polyzirconium oxane as the zirconium source, modified phenolic resin as the carbon source, and polycarbosilane as the silicon source. Some hydroxyl groups in the modified phenolic resin are etherified, and it contains carbon-carbon unsaturated functional groups. The preparation method involves applying high-temperature prepolymerization during the preparation of the nonpolar polyzirconium oxane, and mixing and reacting the zirconium source and carbon source at a certain temperature to obtain the ZrC precursor. This invention, by selecting phenolic resin containing unsaturated functional groups and etherified hydroxyl groups as the carbon source, and simultaneously treating the zirconium source specifically, reduces the residual Zr-OR structure content in the polyzirconium oxane, improving the stability of the zirconium carbide precursor, thereby further improving the storage performance of the multiphase ceramic precursor at room temperature. However, it suffers from a low ceramic conversion rate of only 20-30%.

[0004] Chinese patent CN110156468A discloses a precursor conversion method for preparing ZrC-ZrB2-SiC ceramic composite powder. The method uses zirconium oxychloride octahydrate, boric acid, tetraethyl orthosilicate, and glucose as starting materials, and anhydrous ethanol and deionized water as solvents. The molar ratio of boric acid:zirconium oxychloride octahydrate:tetraethyl orthosilicate is 1-5:1:0.5-5, and the mass ratio of glucose:tetraethyl orthosilicate is 1-4:1. Zirconium precursor solutions, boric acid solutions, tetraethyl orthosilicate solutions, and glucose solutions are prepared separately and mixed evenly to obtain a borosilicate-zirconium precursor solution. After drying the borosilicate-zirconium precursor solution, it is heat-treated at 1450-1600℃ for 1-2 hours under an argon atmosphere to obtain ZrC-ZrB2-SiC ceramic powder. However, the zirconium content in this patent is relatively fixed and low.

[0005] Current methods for preparing Zr / Si multiphase ceramics using precursor conversion often face several key challenges in the organic-to-ceramic conversion process. On one hand, precursors with common linear structures are prone to pyrolysis during curing, leading to the escape of numerous small molecules from the side groups of their molecular chains and resulting in low ceramic yields (often below 45%). On the other hand, insufficient active functional groups at the end groups of the precursor can lead to uneven distribution of the Zr / Si phases and weak interfacial bonding in the final ceramicized product, making it difficult to fully leverage the synergistic reinforcing effect of the multiphase ceramic. Most notably, existing precursor conversion methods for Zr / Si multiphase ceramics generally suffer from a core defect: a relatively fixed Zr / Si component content and a conflict between the need for high ceramic yield and high zirconium content. Furthermore, the processing properties of the precursors, such as solubility, viscosity, and curing behavior, directly affect their practical engineering applications in key areas such as aerospace thermal protection and ultra-high temperature engines.

[0006] Therefore, there is an urgent need to develop a novel multiphase ceramic precursor with a flexible and adjustable zirconium-silicon ratio, good solubility, high curing crosslinking density, excellent ceramic yield, and uniform dispersion of Zr / Si phases in the ceramic product. This precursor should address the technical challenges of severe pyrolysis, insufficient active functional groups, and uneven Zr / Si dispersion in existing precursors from the perspective of molecular structure design, so as to meet the stringent performance requirements of high-end equipment for ultra-high temperature ceramic materials. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a Zr / Si multiphase ceramic precursor based on a zirconium source with active alkenyl side groups and its preparation method.

[0008] The objective of this invention can be achieved through the following technical solutions: A method for preparing a Zr / Si composite ceramic precursor based on a zirconium source with active alkenyl side groups includes the following steps: S1. Using an organozirconium compound as a zirconium source, mix it evenly with a silicon source in a solvent to prepare a mixed solution; S2. The mixed solution obtained in step S1 is thermally cured to obtain a Zr / Si composite ceramic precursor; The structural formula of the organozirconium compound is shown in Formula I: , Wherein, R is -CH2-, -CH2-CH2-, or -CH(CH3)-; The silicon source is hyperbranched vinyl hydrogenated polycarbosilane (VHPCS) or vinyl hydrogenated polysiloxane (VHPSO).

[0009] Furthermore, the method for preparing the organozirconium compound includes: subjecting n-propoxide (as shown in Formula II) to an unsaturated carboxylic acid (as shown in Formula III) via a substitution reaction to obtain a zirconium-containing organic monomer (as shown in Formula IV); and then subjecting the zirconium-containing organic monomer to a hydrolysis-condensation reaction to obtain the organozirconium compound. ; ; ; Where R is -CH2-, -CH2-CH2-, or -CH(CH3)-.

[0010] The reaction process is as follows: .

[0011] Furthermore, the unsaturated carboxylic acid is selected from at least one of acrylic acid, methacrylic acid, and n-butenoic acid; And / or, the molar ratio of zirconium propoxide to unsaturated carboxylic acid is 1:2.0~2.5; And / or, the substitution reaction and hydrolysis-condensation reaction are carried out in an anhydrous solvent; the anhydrous solvent is selected from at least one of ether solvents and alcohol solvents, and the anhydrous solvent does not react with any compound in the reaction system; preferably, the anhydrous solvent is selected from at least one of diethyl ether, tetrahydrofuran, dioxane, n-propanol, isopropanol, and butanol; And / or, both the substitution reaction and the hydrolysis-condensation reaction are carried out under inert gas protection; And / or, the reaction temperature of the substitution reaction is 0~40℃ and the reaction time is 12~72 h; the reaction temperature is controlled below 40℃ to suppress the violent exothermic reaction during the addition of unsaturated carboxylic acids and the side reactions during the dropwise addition process; And / or, the hydrolysis-condensation reaction is carried out at a temperature of room temperature to 100°C for a time of 1 to 6 hours. And / or, the pH of the reaction solution for the hydrolysis-condensation reaction is 1-5, and the pH of the system is adjusted using nitric acid; And / or, after the preparation of the organozirconium compound is completed, a post-processing is performed, wherein the post-processing is: removing the solvent and unreacted monomer by rotary evaporation to obtain the purified organozirconium compound.

[0012] Furthermore, the structural formula of the hyperbranched vinyl hydrogenated polycarbosilane is shown in Formula V: , The structural formula of the vinyl hydrogenated polysiloxane is shown in Formula XII: , Where z is the molar ratio of structural units containing vinyl side groups to the total number of structural units in the molecular chain.

[0013] Furthermore, the preparation method of the hyperbranched vinyl hydrogenated polycarbosilane includes the following steps: S1. The chloromethyltrichlorosilane shown in Formula VI is partially methoxylated and substituted with methanol shown in Formula VII to obtain an intermediate monomer as shown in Formula VIII. S2. The reaction intermediate monomer obtained in step S1 is subjected to a Grignard reaction with metallic magnesium to obtain the compound shown in Formula IX. Then, it is mixed with the vinyl magnesium chloride Grignard reagent shown in Formula X and subjected to a Grignard condensation reaction to obtain a polymer reaction intermediate with a hyperbranched structure containing chlorine at the end group, as shown in Formula XI. S3. The chlorine-terminated polymeric reaction intermediate obtained in step S2 is reduced with lithium aluminum hydride to obtain hyperbranched vinyl hydrogenated polycarbosilane.

[0014] The reaction route is as follows: .

[0015] Furthermore, the molar ratio of methanol to chloromethyltrichlorosilane is 0.1~3:1; that is, the proportion of methoxy group y in formula VIII is 0.1~3; preferably, y is 1~1.75; And / or, the molar amount of the vinyl magnesium chloride Grignard reagent is 0.1 to 1 times the total molar amount of chloromethyltrichlorosilane, corresponding to a molar percentage z of 0.1 to 1 for the vinyl side group structural unit in formula V, preferably z is 0.2 to 0.6; And / or, the reaction temperature of the substitution reaction is 0~40℃, and the reaction time is 10~36 hours; And / or, the Grignification reaction is carried out at a temperature of 50-70°C for a duration of 1-4 hours; And / or, the Grignard condensation reaction is carried out at a temperature of 50-70°C for a duration of 12-24 hours; And / or, the reduction reaction is carried out at a temperature of 40-70°C for a duration of 5-20 hours.

[0016] And / or, the entire preparation process of the hyperbranched vinyl hydrogenated polycarbosilane is carried out in an anhydrous, oxygen-free, and inert gas-protected environment; And / or, the solvent used in the reaction is an ultra-dry solvent, selected from at least one of ethers and aromatic solvents, and does not participate in the reaction; preferably, the ultra-dry solvent is selected from one or more of diethyl ether, tetrahydrofuran, dioxane, toluene, and xylene; And / or, the magnesium metal used in the Grignard condensation reaction is at least one of magnesium shavings or magnesium powder; And / or, in the reduction reaction, lithium aluminum hydride is added at -10 to 25°C; the main purpose of setting the addition temperature below 25°C is to prevent the reaction system from releasing a large amount of heat after the addition of lithium aluminum hydride; And / or, after the reaction is completed, post-treatment is performed, which includes quenching with ice water and n-hexane, separation, drying with anhydrous sodium sulfate, and rotary evaporation to remove solvent.

[0017] Furthermore, the method for preparing the vinyl hydrogenated polysiloxane includes: Methyl dichlorosilane of Formula XIII and methyl vinyl dichlorosilane of Formula XIV are mixed in hexane, and then deionized water is added dropwise under an ice-water bath to carry out a hydrolysis-condensation reaction. After the addition is complete, the reaction continues to obtain vinyl hydrogenated polysiloxane.

[0018] The reaction route is as follows: .

[0019] Furthermore, the molar amount of the methylvinyldichlorosilane is 0.2 to 0.6 times the total molar amount of the chlorosilane monomer, corresponding to a molar percentage z of vinyl structural units in the product of 0.2 to 0.6. And / or, in the hydrolysis-condensation reaction, the molar amount of deionized water added is 3 to 20 times the total molar amount of chlorosilane monomer; And / or, the temperature of the hydrolysis-condensation reaction is -10~30℃, the reaction time is 1~3 h, and the preferred reaction temperature is 20~30℃; the main purpose of setting this temperature is to prevent a large amount of heat from being released after the addition of chlorosilane, which would make it difficult to control the degree of polymerization.

[0020] And / or, after the preparation of the vinyl hydrogenated polysiloxane is completed, post-processing is performed, including n-hexane extraction, drying with anhydrous sodium sulfate, filtration, and rotary evaporation to remove solvent.

[0021] Furthermore, in the Zr / Si multiphase ceramic precursor, the molar ratio of zirconium to silicon is 10:1 to 1:10; And / or, the solvent is selected from one or more of alcohol reagents, ether reagents, and aromatic reagents; preferably, the solvent is selected from one or more of diethyl ether, tetrahydrofuran, dioxane, ethanol, n-propanol, isopropanol, benzene, toluene, and xylene.

[0022] And / or, the solid content of the solution (based on the total mass of the zirconium source and the silicon source) is 20 to 80 wt%.

[0023] The present invention also provides a Zr / Si composite ceramic precursor based on a zirconium source containing active alkenyl side groups, wherein the Zr / Si composite ceramic precursor is prepared by the preparation method described in any of the above claims; the zirconium-silicon ratio of the precursor is adjustable, both the zirconium source and the silicon source contain terminal active functional groups, and it has a high ceramic conversion rate.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention, through molecular structure design, simultaneously introduces crosslinkable active functional groups such as vinyl groups and silane groups at the ends of zirconium and silicon source molecules, enabling the precursor to undergo efficient addition crosslinking during the curing stage, forming a high crosslinking density network structure. This significantly reduces the thermal desorption of small molecule compounds during the pyrolysis process, suppressing volume shrinkage and defect generation at the source, and significantly improving the curing quality retention rate and high-temperature ceramicization yield. Simultaneously, the zirconium source used in this invention has small oxygen-containing groups and high thermal stability, resulting in fewer small molecule components that can be removed during curing and ceramicization, further reducing mass loss and maintaining excellent ceramic yield even under high zirconium content conditions.

[0025] (2) The organozirconium compound prepared by the present invention using olefinic compounds such as acrylic acid as ligands contains carbon-carbon double bond active end groups in the molecule, which can not only participate in cross-linking and curing, but also catalyze the curing reaction. It can effectively reduce the initial curing temperature and peak curing temperature of the system, so that the precursor can complete cross-linking under milder conditions, and reduce the energy consumption and side reactions caused by high temperature pre-curing.

[0026] (3) The zirconium source and silicon source used in this invention are miscible in any proportion in common solvents, exhibiting excellent compatibility. The Zr / Si molar ratio can be precisely controlled within the range of 10:1 to 1:10, meeting the composition design requirements of different scenarios. The high cross-linking density structure can effectively suppress phase segregation during high-temperature pyrolysis, ensuring uniform distribution of Zr and Si elements in the ceramic product. This fully leverages the synergistic enhancement effect of multiphase ceramics, solving the key problems of uneven two-phase structure and weak interfacial bonding in traditional precursors.

[0027] (4) The precursor of this invention has good solubility and viscosity below 70 mPa·S, excellent rheological and processing properties, and is suitable for various molding processes such as coating, impregnation, molding, and additive manufacturing. Its typical performance indicators are outstanding: ceramic conversion rate at 1000℃ is higher than 90%, and ceramic conversion rate at 1600℃ is higher than 45%, which combines high ceramic yield with high-temperature structural stability, and can meet the stringent requirements of aerospace thermal protection systems, ultra-high temperature engine components, etc. for complex shapes and high-performance high-temperature structural ceramics.

[0028] (5) Starting from the design of precursor molecules, this invention simultaneously solves a series of problems in traditional Zr / Si multiphase ceramic precursors, such as low yield, non-tunability of zirconium and silicon, poor dispersibility, poor processability, and easy cracking. It greatly improves the comprehensive performance of materials and powerfully promotes the industrial application of precursor conversion method in the field of high-performance multiphase ceramics. It is especially suitable for the manufacturing of key hot-end components of high-end equipment. Attached Figure Description

[0029] Figure 1 The FT-IR spectrum of the zirconium-containing organic compound diacrylate polyzirconoxane prepared in Example 1 is shown below. Figure 2The DSC image of the Zr / Si multiphase ceramic precursor prepared in Example 6 under a nitrogen atmosphere; Figure 3 TGA image of the Zr / Si multiphase ceramic precursor cured product prepared in Example 6 under nitrogen atmosphere; Figure 4 The XRD pattern of the ceramicized product of the Zr / Si multiphase ceramic precursor prepared in Example 6; Figure 5 TGA image of the Zr / Si multiphase ceramic precursor cured product prepared in Example 7 under nitrogen atmosphere; Figure 6 The XRD pattern of the ceramicized product of the Zr / Si multiphase ceramic precursor prepared in Example 7; Figure 7 XRD pattern of the ceramicized product of the Zr / Si multiphase ceramic precursor prepared in Example 8; Figure 8 Transmission electron microscope (TEM) images and corresponding EDS mapping images of the ceramicized products of the Zr / Si multiphase ceramic precursor prepared in Example 8. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0031] For experimental methods in the following examples where specific conditions are not specified, follow conventional methods and conditions, or select according to the product instructions.

[0032] Unless otherwise specified, all raw materials used in this invention are commercially available products.

[0033] In this invention, the structure of the zirconium-containing organic compound was characterized using Fourier transform infrared spectroscopy (FT-IR); the curing temperature range of the precursor was measured using differential scanning calorimetry (DSC) under a N2 atmosphere at a heating rate of 10 °C / min. The 5% thermogravimetric temperature of the cured product (…) T d5 ) and the residual rate of thermal decomposition at 1000℃ ( Y r1000 The ablation resistance of the ceramized products was tested using a thermogravimetric analyzer under N2 atmosphere at a heating rate of 10℃ / min. The material structure analysis of the ceramized products was determined using X-ray polycrystalline diffraction (XRD) with a measurement range of 10~80° and metallic copper as the target material.

[0034] Example 1 The specific preparation steps for diacrylate-based polyzirconoxane are as follows: 500 mL of a 70% zirconium propoxide solution (containing 1.07 mol of zirconium propoxide) was added to a 1000 mL four-necked flask equipped with a stirrer, thermometer, constant-pressure dropping funnel, and reflux condenser. The temperature was maintained at 25 °C in an ice-water bath. 154.08 g of acrylic acid (2.14 mol) was slowly added dropwise through the constant-pressure dropping funnel while stirring at 500 rpm. After the addition was complete, the reaction was continued at room temperature for 24 h to obtain a milky white suspension containing the compound shown in Formula IV. Nitric acid was then added dropwise to adjust the pH to 3, and the temperature was raised to 80 °C and maintained for 2 h to obtain a clear yellow liquid. After removing the solvent by rotary evaporation, a yellow gel-like product, diacrylate polyzirconium oxane, was finally obtained.

[0035] Figure 1 Fourier transform infrared (FT-IR) characterization results of diacrylate-based polyzirconium oxane: 3250 cm⁻¹ -1 The broad peak at 3000 cm⁻¹ is the hydroxyl peak; -1 The left and right sides are the CH bending vibration peaks; 1630~1641 cm. -1 The sharp, strong peak at 1500-1600 cm⁻¹ is attributed to the stretching vibration of the C=C bond in the allyl group, and the appearance of this peak proves that the co-hydrolysis reaction of acrylic acid has occurred; -1 A set of strong peaks at 1260 cm⁻¹ contains bending vibration peaks of the Zr-O-Zr bond; -1 The peak at 1000 cm⁻¹ represents the bending vibration of the CH bond in the allyl group. -1 The nearby area corresponds to the characteristic absorption of CO bond stretching vibration.

[0036] Example 2 The specific preparation steps for dimethacrylate-based polyzirconoxane are as follows: 500 mL of a 70% zirconium propoxide solution (containing 1.07 mol of zirconium propoxide) was added to a 1000 mL four-necked flask equipped with a stirrer, thermometer, constant-pressure dropping funnel, and reflux condenser. The temperature was maintained at 25 °C in an ice-water bath. 184.23 g (2.14 mol) of methacrylic acid mixed with 50 mL of tetrahydrofuran was slowly added dropwise through the constant-pressure dropping funnel while stirring at 500 rpm. After the addition was complete, the reaction was continued at room temperature for 48 h to obtain a milky white suspension containing the compound shown in Formula IV. Nitric acid was then added dropwise to adjust the pH to 3, and the temperature was raised to 40 °C and maintained for 6 h to obtain a clear yellow liquid. After removing the solvent by rotary evaporation, a yellow gel-like product, dimethacrylate-based polyzirconium oxane, was finally obtained.

[0037] Example 3 The specific preparation steps for di-n-butenoic acid-based polyzirconoxane are as follows: 500 mL of a 70% zirconium propoxide solution (containing 1.07 mol of zirconium propoxide) was added to a 1000 mL four-necked flask equipped with a stirrer, thermometer, constant-pressure dropping funnel, and reflux condenser. The temperature was maintained at 25 °C in an ice-water bath. 184.23 g (2.14 mol) of butenoic acid mixed with 50 mL of tetrahydrofuran was slowly added dropwise through the constant-pressure dropping funnel while stirring at 500 rpm. After the addition was complete, the reaction was continued at room temperature for 48 h to obtain a milky white suspension containing the compound shown in Formula IV. Nitric acid was then added dropwise to adjust the pH to 3, and the temperature was raised to 40 °C and maintained for 6 h to obtain a clear yellow liquid. After removing the solvent by rotary evaporation, a yellow gel-like product, di-butenoic acid-based polyzirconium oxane, was finally obtained.

[0038] Example 4 The specific preparation steps for vinyl hydrogenated polysiloxane (VHPSO) are as follows: Add 50 mL of deionized water to a 250 mL four-necked flask equipped with a stirrer, thermometer, constant-pressure dropping funnel, and condenser, and purged with nitrogen. Add 0.1 mol of methyldichlorosilane and 0.25 mol of methylvinyldichlorosilane to the constant-pressure dropping funnel, followed by 70 mL of n-hexane as a solvent and 3 g of tetrahydrofuran, to obtain a chlorosilane mixed solution. Under ice-water bath conditions, slowly add this chlorosilane mixed solution to deionized water over a period of 1 h. After the addition is complete, continue the reaction at room temperature for 2 h. After the reaction is complete, extract and separate the solutions, dry them, and then distill under reduced pressure to finally obtain vinyl hydrogenated polysiloxane (VHPSO).

[0039] Example 5 The specific preparation steps for hyperbranched vinyl hydrogenated polycarbosilanes (VHPCS) are as follows: S1. Add 36.785 g (0.2 mol, 24.92 mL) of chloromethyltrichlorosilane to a 500 mL four-necked flask equipped with a stirrer, thermometer, constant-pressure dropping funnel, and condenser, and purged with nitrogen. Measure 11.214 g (0.35 mol, 14.18 mL) of anhydrous methanol into the constant-pressure dropping funnel and add it slowly at a rate of 5–10 drops per second. After the anhydrous methanol has been added, continue stirring the reaction at room temperature for 12 h.

[0040] S2. Take another 500 mL four-necked flask, purge it with nitrogen, and add 6.57 g (0.27 mol) of magnesium powder, 50 mL of tetrahydrofuran (THF), and 0.345 mL of dibromoethane in sequence. Transfer the product obtained in step S1 to a constant-pressure dropping funnel, and after the system cools to about 25°C, slowly add the product dropwise until it is completely absorbed. After the chlorosilane material is added, continue to add 20 mL of a 2 mol / L vinyl magnesium chloride solution. After the addition is complete, stir at room temperature for 30 min, then heat to reflux and maintain the temperature for 3 h.

[0041] S3. Place the reaction system from step S2 in an ice-water bath and stir rapidly to cool. Slowly add 46.8 mL of a 2.5 mol / L lithium aluminum hydride solution (0.117 mol in amount, tetrahydrofuran as solvent) to the system using a syringe. After the addition is complete, stir at room temperature for 30 min, then raise the temperature to 60°C and stir continuously at a constant temperature for 3 h.

[0042] S4. In a glass reaction vessel, 75 mL of 38% concentrated hydrochloric acid, 250 g of crushed ice, and 250 mL of n-hexane were mixed. The n-hexane-hydrochloric acid mixture was vigorously stirred using a mechanical stirrer. Under rapid stirring, the reduced mixture was slowly poured into the low-temperature n-hexane-hydrochloric acid mixture, and stirring was continued for 10 min. After standing for 5-10 min to separate the layers, a yellow organic phase precipitated on the upper layer of the aqueous phase. Deionized water was added and stirring was continued for about 10 min, followed by standing for another 5-10 min to separate the layers. The mixture was then filtered and separated by liquid-liquid separation. The organic phase was washed with water 3-4 times and dried with anhydrous sodium sulfate for 2 h. After filtering out the drying agent, the mixture was washed with n-hexane and filtered again. The solvent was removed by rotary evaporation, and finally, colorless and transparent hyperbranched vinyl hydrogenated polycarbosilane (VHPCS) was obtained.

[0043] Example 6 Preparation and ceramicization of Zr / Si multiphase ceramic precursor 1.36 g of tetrahydrofuran was used as a solvent, and 2 g of diacrylate-based polyzirconium oxane prepared in Example 1 and 0.05 g of hyperbranched vinyl hydrogenated polycarbosilane (VHPCS) prepared in Example 5 were added. The mixture was stirred until the system was homogeneous, and a multiphase ceramic precursor solution with a solid content of 60 wt% and a Zr / Si molar ratio of 8:1 was obtained.

[0044] The above-mentioned multiphase ceramic precursor solution was subjected to segmented thermosetting treatment in an air atmosphere. For example... Figure 2As shown in the DSC curve of the precursor, the system exhibits two distinct exothermic peaks, with an initial curing temperature of 175℃ and peak curing temperatures of 214℃ and 276℃, respectively. Based on this, a stepped curing regime was adopted: 100℃ for 2 h → 170℃ for 2 h → 210℃ for 2 h → 250℃ for 2 h → 280℃ for 2 h. After curing, a homogeneous brownish-red solid product was obtained, with a product mass of 1.97 g and a cured mass retention rate of approximately 96%.

[0045] like Figure 3 As shown, the residual rate of the cured product after thermal decomposition at 1000℃ under a nitrogen atmosphere is... Y r1000 It is 71%.

[0046] The cured product was placed in an argon atmosphere and subjected to high-temperature ceramization treatment according to a segmented heating regime: 100℃ for 1 h → 200℃ for 2 h → 500℃ for 2 h → 750℃ for 2 h → 1000℃ for 2 h → 1200℃ for 2 h → 1400℃ for 2 h → 1600℃ for 4 h. Finally, a black Zr / Si multiphase ceramic was obtained, with a ceramization yield of 49%. The XRD pattern of the ceramized product is shown below. Figure 4 As shown.

[0047] Example 7 Preparation and ceramicization of Zr / Si multiphase ceramic precursor In 3.41 g of tetrahydrofuran, 2 g of diacrylated polyzirconium oxane prepared in Example 1 and 3.42 g of hyperbranched vinyl hydrogenated polycarbosilane (VHPCS) prepared in Example 5 were mixed evenly to obtain a multiphase ceramic precursor solution with a solid content of 60 wt% and a Zr / Si molar ratio of 1:8.

[0048] In an air atmosphere, the above-mentioned multiphase ceramic precursor solution was cured according to the following stepped heating process: 100℃ for 2 h → 170℃ for 2 h → 210℃ for 2 h → 250℃ for 2 h → 280℃ for 2 h. After curing, a uniform pale yellow solid product with a mass of 2.473 g was obtained, and the curing mass retention rate was 97%.

[0049] like Figure 5 As shown, the 5% thermogravimetric temperature of the solidified material under N2 atmosphere is... T d5 The thermal decomposition residue rate at 528℃ and 1000℃ is... Y r1000 It is 90%.

[0050] The obtained cured product was ceramicized under an Ar atmosphere according to the following heating process: 100℃ for 1 h → 200℃ for 2 h → 500℃ for 2 h → 750℃ for 2 h → 1000℃ for 2 h → 1200℃ for 2 h → 1400℃ for 2 h → 1600℃ for 4 h, to obtain black Zr / Si multiphase ceramic with a ceramicization yield of 45%.

[0051] The XRD pattern of the obtained ceramization product is as follows: Figure 6 As shown.

[0052] Example 8 Preparation and ceramicization of Zr / Si multiphase ceramic precursor In 1.59 g of tetrahydrofuran, 2 g of diacrylated polyzirconium oxane prepared in Example 1 and 0.39 g of hyperbranched vinyl hydrogenated polycarbosilane (VHPCS) prepared in Example 5 were mixed evenly to obtain a multiphase ceramic precursor solution with a solid content of 60 wt% and a Zr / Si molar ratio of 1:1.

[0053] In an air atmosphere, the above-mentioned multiphase ceramic precursor solution was cured according to the following stepped heating process: 100℃ for 2 h → 170℃ for 2 h → 210℃ for 2 h → 250℃ for 2 h → 280℃ for 2 h. After curing, a uniform pale yellow solid product of 2.17 g was obtained, with a curing quality retention rate of 91%.

[0054] The residual rate of the solidified material after thermal decomposition at 1000℃ under N2 atmosphere Y r1000 It is 85%.

[0055] The obtained cured product was ceramicized under an Ar atmosphere according to the following heating process: 100℃ for 1 h → 200℃ for 2 h → 500℃ for 2 h → 750℃ for 2 h → 1000℃ for 2 h → 1200℃ for 2 h → 1400℃ for 2 h → 1600℃ for 4 h, to obtain black Zr / Si multiphase ceramic with a ceramicization yield of 45%.

[0056] The XRD pattern of the obtained ceramization product is as follows: Figure 7 As shown.

[0057] Transmission electron microscope images and corresponding EDS mapping images of the obtained ceramization products are shown below. Figure 8 As shown, zirconium, silicon, and carbon are represented by cyan, green, and yellow, respectively. The uniform dispersion of zirconium and silicon in the figure demonstrates that the zirconium-containing and silicon-containing components are evenly distributed in the ceramization product, achieving the goal of synergistic reinforcement in multiphase ceramics.

[0058] Example 9 Preparation and ceramicization of Zr / Si multiphase ceramic precursor In a 1.8 g dioxane solution, 2 g of dimethacrylate-based polyzirconium oxane prepared in Example 2 and 0.78 g of hyperbranched vinyl hydrogenated polycarbosilane (VHPCS) prepared in Example 5 were mixed evenly to obtain a multiphase ceramic precursor solution with a solid content of 60 wt% and a Zr / Si molar ratio of 1:2.

[0059] In an air atmosphere, the above-mentioned multiphase ceramic precursor solution was cured according to the following stepped heating process: 110℃ for 2 h → 170℃ for 2 h → 210℃ for 2 h → 250℃ for 2 h → 280℃ for 2 h. After curing, a uniform yellow solid product was obtained.

[0060] The obtained cured product was ceramicized under an Ar atmosphere according to the following heating process: 100℃ for 1 h → 200℃ for 2 h → 500℃ for 2 h → 750℃ for 2 h → 1000℃ for 2 h → 1200℃ for 2 h → 1400℃ for 2 h → 1600℃ for 4 h, to obtain black Zr / Si multiphase ceramic.

[0061] Example 10 Preparation and ceramicization of Zr / Si multiphase ceramic precursor 1 g of diacrylated polyzirconium oxane prepared in Example 1 and 0.27 g of vinyl hydrogenated polysiloxane (VHPSO) prepared in Example 4 were mixed evenly in 0.85 g of tetrahydrofuran to obtain a multiphase ceramic precursor solution with a solid content of 60 wt% and a Zr / Si molar ratio of 1:1.

[0062] In an air atmosphere, the above-mentioned multiphase ceramic precursor solution was cured according to the following stepped heating process: 110℃ for 2 h → 170℃ for 2 h → 210℃ for 2 h → 250℃ for 2 h → 280℃ for 2 h. After curing, 1.16 g of uniform yellow solid product was obtained, with a curing quality retention rate of 91%.

[0063] The residual rate of the solidified material after thermal decomposition at 1000℃ under N2 atmosphere Y r1000 It is 75%.

[0064] The obtained cured product was ceramicized under an Ar atmosphere according to the following heating process: 100℃ for 1 h → 200℃ for 2 h → 500℃ for 2 h → 750℃ for 2 h → 1000℃ for 2 h → 1200℃ for 2 h → 1400℃ for 2 h → 1600℃ for 4 h, to obtain black multiphase ceramic with a ceramicization yield of 48%.

[0065] Example 11 Preparation and ceramicization of Zr / Si multiphase ceramic precursor 1 g of diacrylated polyzirconium oxane prepared in Example 1 and 1.95 g of vinyl hydrogenated polysiloxane (VHPSO) prepared in Example 4 were mixed evenly in 1.96 g of tetrahydrofuran to obtain a multiphase ceramic precursor solution with a solid content of 60 wt% and a Zr / Si molar ratio of 1:10.

[0066] In an air atmosphere, the above-mentioned multiphase ceramic precursor was cured according to the following stepped heating process: 110℃ for 2 h → 170℃ for 2 h → 210℃ for 2 h → 250℃ for 2 h → 280℃ for 2 h. After curing, a uniform yellow solid product of 2.77 g was obtained, with a curing quality retention rate of 94%.

[0067] The residual rate of the solidified material after thermal decomposition at 1000℃ under N2 atmosphere Y r1000 It is 92%.

[0068] The obtained cured product was ceramicized under an Ar atmosphere according to the following heating process: 100℃ for 1 h → 200℃ for 2 h → 500℃ for 2 h → 750℃ for 2 h → 1000℃ for 2 h → 1200℃ for 2 h → 1400℃ for 2 h → 1600℃ for 4 h, to obtain black multiphase ceramic with a ceramicization yield of 67%.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a Zr / Si multiphase ceramic precursor based on a zirconium source containing active alkenyl side groups, characterized in that, Includes the following steps: S1. Using an organozirconium compound as a zirconium source, mix it evenly with a silicon source in a solvent to prepare a mixed solution; S2. The mixed solution obtained in step S1 is thermally cured to obtain a Zr / Si composite ceramic precursor; The structural formula of the organozirconium compound is shown in Formula I: ， Wherein, R is -CH2-, -CH2-CH2-, or -CH(CH3)-; The silicon source is a hyperbranched vinyl hydrogenated polycarbosilane or a vinyl hydrogenated polysiloxane.

2. The preparation method according to claim 1, characterized in that, The method for preparing the organozirconium compound includes: subjecting zirconium n-propoxide to an unsaturated carboxylic acid via a substitution reaction to obtain a zirconium-containing organic monomer; and then subjecting the zirconium-containing organic monomer to a hydrolysis-condensation reaction to obtain the organozirconium compound.

3. The preparation method according to claim 2, characterized in that, The unsaturated carboxylic acid is selected from at least one of acrylic acid, methacrylic acid, and n-butenoic acid; And / or, the molar ratio of zirconium propoxide to unsaturated carboxylic acid is 1:2.0~2.5; And / or, the substitution reaction and hydrolysis-condensation reaction are carried out in an anhydrous solvent; the anhydrous solvent is selected from at least one of ether solvents and alcohol solvents; And / or, both the substitution reaction and the hydrolysis-condensation reaction are carried out under inert gas protection; And / or, the reaction temperature of the substitution reaction is 0~40℃, and the reaction time is 12~72 h; And / or, the hydrolysis-condensation reaction is carried out at a temperature of room temperature to 100°C for a time of 1 to 6 hours. And / or, the pH of the reaction solution for the hydrolysis-condensation reaction is 1-5; And / or, after the preparation of the organozirconium compound is completed, a post-processing is performed, wherein the post-processing is: removing the solvent and unreacted monomer by rotary evaporation to obtain the purified organozirconium compound.

4. The preparation method according to claim 1, characterized in that, The structural formula of the hyperbranched vinyl hydrogenated polycarbosilane is shown in Formula V: ， The structural formula of the vinyl hydrogenated polysiloxane is shown in Formula XII: ， Where z is the molar ratio of structural units containing vinyl side groups to the total number of structural units in the molecular chain.

5. The preparation method according to claim 4, characterized in that, The preparation method of the hyperbranched vinyl hydrogenated polycarbosilane includes the following steps: S1. Chloromethyltrichlorosilane is partially methoxylated with methanol to obtain an intermediate monomer. S2. The intermediate monomer obtained in step S1 is subjected to Grignard reaction with metallic magnesium, then mixed with vinyl magnesium chloride Grignard reagent and subjected to Grignard condensation reaction to obtain a polymeric reaction intermediate with chlorine end group. S3. The chlorine-terminated polymeric reaction intermediate obtained in step S2 is reduced with lithium aluminum hydride to obtain hyperbranched vinyl hydrogenated polycarbosilane.

6. The preparation method according to claim 5, characterized in that, The molar ratio of methanol to chloromethyltrichlorosilane is 0.1 to 3:1; And / or, the molar amount of the vinyl magnesium chloride Grignard reagent is 0.1 to 1 times the total molar amount of chloromethyltrichlorosilane; And / or, the reaction temperature of the substitution reaction is 0~40℃, and the reaction time is 10~36 hours; And / or, the Grignification reaction is carried out at a temperature of 50-70°C for a duration of 1-4 hours; And / or, the Grignard condensation reaction is carried out at a temperature of 50-70°C for a duration of 12-24 hours; And / or, the reduction reaction is carried out at a temperature of 40-70°C for a duration of 5-20 hours; And / or, the solvent used in the reaction is an ultra-dry solvent, selected from at least one of ethers and aromatic solvents, and does not participate in the reaction; And / or, the magnesium metal used in the Grignard condensation reaction is at least one of magnesium shavings or magnesium powder; And / or, in the reduction reaction, lithium aluminum hydride is added at -10 to 25°C; And / or, after the reaction is completed, post-treatment is performed, which includes quenching with ice water and n-hexane, separation, drying with anhydrous sodium sulfate, and rotary evaporation to remove solvent.

7. The preparation method according to claim 4, characterized in that, The method for preparing the vinyl hydrogenated polysiloxane includes: Methyldichlorosilane and methylvinyldichlorosilane were mixed in hexane, and then deionized water was added dropwise under an ice-water bath to carry out a hydrolysis-condensation reaction. After the addition was complete, the reaction continued to obtain vinyl hydrogenated polysiloxane.

8. The preparation method according to claim 7, characterized in that, The molar amount of the methylvinyldichlorosilane is 0.2 to 0.6 times the total molar amount of the chlorosilane monomer; And / or, in the hydrolysis-condensation reaction, the molar amount of deionized water added is 3 to 20 times the total molar amount of chlorosilane monomer; And / or, the hydrolysis-condensation reaction is carried out at a temperature of -10 to 30°C for a duration of 1 to 3 hours; And / or, after the preparation of the vinyl hydrogenated polysiloxane is completed, post-processing is performed, including n-hexane extraction, drying with anhydrous sodium sulfate, filtration, and rotary evaporation to remove solvent.

9. The preparation method according to claim 1, characterized in that, In the Zr / Si multiphase ceramic precursor, the molar ratio of zirconium to silicon is 10:1 to 1:

10. And / or, the solvent is selected from one or more of alcohol reagents, ether reagents, and aromatic reagents; And / or, the solid content of the solution is 20-80 wt%.

10. A Zr / Si multiphase ceramic precursor based on a zirconium source containing active alkenyl side groups, characterized in that, The Zr / Si multiphase ceramic precursor is prepared by the preparation method according to any one of claims 1 to 9.

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