阅读说明：本技术 一种采用溶胶-凝胶法制备ZrO2-SiO2-SiC涂层C/C复合材料的方法 (ZrO preparation by adopting sol-gel method2-SiO2Method for coating C/C composite material with-SiC ) 是由 陈晓红 卢亚平 李孟 于 2021-01-05 设计创作，主要内容包括：一种采用溶胶-凝胶法制备ZrO-2-SiO-2-SiC涂层C/C复合材料的方法,属于先进复合抗氧化涂层材料技术领域。该方法首先制得均匀的包覆在C/C复合材料表面的SiC涂层,随后采用溶胶-凝胶法制得ZrO-2-SiO-2二元混合溶胶涂层。将SiC涂层C/C复合材料试样常压浸渍于ZrO-2-SiO-2溶胶中,然后经过干燥和高温热处理工序,制得高纯度ZrO-2-SiO-2-SiC三元混合溶胶涂层。该复合涂层能均匀致密地覆盖C/C复合材料,大幅提高C/C复合材料的抗氧化性能。该发明使单层SiC涂层表面的微孔、裂纹等缺陷被SiO-2、ZrO-2填充,大大提高了涂层的致密性,因而获得了抗氧化能力极强的复合涂层材料。(ZrO preparation by adopting sol-gel method 2 ‑SiO 2 A method for preparing a-SiC coating C/C composite material, belonging to the technical field of advanced composite anti-oxidation coating materials. The method comprises the steps of preparing a uniform SiC coating coated on the surface of a C/C composite material, and preparing ZrO by adopting a sol-gel method 2 ‑SiO 2 Binary mixed sol coating. Soaking a SiC coating C/C composite material sample in ZrO at normal pressure 2 ‑SiO 2 In the sol, drying and high-temperature heat treatment are carried out to prepare high-purity ZrO 2 ‑SiO 2 -SiC ternary hybrid sol coating. The composite coating can uniformly and compactly cover the C/C composite material, and the oxidation resistance of the C/C composite material is greatly improved. The invention ensures that the defects of micropores, cracks and the like on the surface of the single-layer SiC coating are covered by SiO 2 、ZrO 2 The compactness of the coating is greatly improved by filling, so that the composite coating material with strong oxidation resistance is obtained.)

1. ZrO preparation by adopting sol-gel method₂-SiO₂-a method for coating a C/C composite with SiC, characterized in that it essentially comprises the following steps:

step (1) preparing SiO₂Sol, ZrO₂Mixing the sol according to a certain molar ratio, and magnetically stirring for a certain time at room temperature.

Step (2) soaking a SiC coating C/C composite material sample prepared from MTES sol with a certain mass fraction in ZrO at normal pressure₂-SiO₂In the sol, when no obvious air bubble escapes from the surface of the sample, the sample is placed in an oven with a certain temperature for drying for a certain time, and the steps are repeated.

Step (3) putting the C/C composite material judgment sample into a graphite crucible, putting the graphite crucible into a high-temperature carbonization furnace, taking high-purity nitrogen as protective atmosphere, controlling the temperature rise rate of the carbonization furnace, raising the temperature of the furnace from room temperature to a certain temperature, and keeping the temperature for a section at a constant temperatureTime to obtain ZrO₂-SiO₂-a SiC coating.

2. The method according to claim 1, wherein in step (1) Zr is selected: zirconium-silicon mixed sol with Si ratio of 4; stirred magnetically at room temperature for 1.5 h.

3. The method according to claim 1, wherein the step (2) is to select MTES sol with the mass fraction of 7% to prepare the SiC coating; the sample was dried in an oven at 80 ℃ for 2 h.

4. The method according to claim 1, wherein the step (3) of controlling the temperature rise rate of the carbonization furnace to 5 ℃/min, maintaining the temperature of the carbonization furnace at a constant temperature of 2 hours from room temperature to 900 ℃ and at a constant temperature of 1350 ℃ for 1 hour to obtain ZrO₂-SiO₂-a SiC coating.

5. High purity ZrO prepared by the process according to any one of claims 1 to 4₂-SiO₂the-SiC ternary mixed sol coating is characterized in that the coating can uniformly and compactly cover the C/C composite material, plays a certain role in protecting the C/C composite material and greatly improves the oxidation resistance of the C/C composite material.

Technical Field

ZrO preparation by adopting sol-gel method₂-SiO₂A method for preparing a-SiC coating C/C composite material, belonging to the technical field of advanced composite anti-oxidation coating materials.

Background

The C/C composite material is a carbon matrix composite material taking carbon fibers as a reinforcing phase, and has a plurality of excellent properties, such as low density, thermal shock resistance, friction resistance, ablation resistance, high strength and high modulus, and low thermal expansion coefficient. And with the rise of temperature, the mechanical property of the C/C composite material is enhanced, so that the composite material is obtained in various fields such as aerospace, military, biomedical treatment and the likeIs widely applied. However, when the C/C composite material is in an oxygen atmosphere at the temperature of more than 370 ℃ and the water vapor temperature exceeds 650 ℃, CO₂When the temperature exceeds 750 ℃, oxidation reaction can occur, which greatly restricts the application of the C/C composite material. Therefore, the improvement and the improvement of the high-temperature oxidation resistance of the C/C composite material are leading edges and hot spots of research in the application field of the current C/C composite material.

Aiming at the oxidation process of the C/C composite material, two main ways for improving the oxidation resistance of the C/C composite material are provided at present: the first is the oxidation resistance technology of the C/C composite material, namely the preparation process of the C/C composite material. The carbon fiber and the matrix carbon are modified, and the oxidation resistance of the carbon fiber and the matrix carbon is improved by adding some oxidation-resistant and ablation-resistant components; secondly, preparing an anti-oxidation coating, wherein the C/C composite material is isolated from O by preparing the C/C composite material on the surface₂Oxidation resistant coating of, avoiding O₂Directly contacts with the C/C composite material, thereby achieving the purpose of oxidation resistance. At present, the external anti-oxidation coating technology is the best means for improving the high-temperature anti-oxidation performance of the C/C composite material.

Compared with the composite antioxidant coating, the single antioxidant coating has very limited protection on the C/C composite material. This is because the oxidation mechanism of the C/C composite material is different at different temperatures, and the oxidation resistance of different oxidation-resistant coating systems is different. For example, the glass coating has good self-healing performance, but the oxidation resistance temperature is low due to the defects of volatility and fluidity at high temperature, and the application of the glass coating in the oxidation resistance field is greatly limited. The metal coating and the ceramic coating have high melting points and higher heat-resistant temperature, but the coating can fall off from the surface of the C/C composite material at high temperature, so that the service life of the coating is limited. The composite coating has the advantages that the advantages of the coatings are combined to make up the defects of the coatings, so that the oxidation resistance of the composite coating is greatly improved.

Disclosure of Invention

In view of the above problems, the present invention is to produce ZrO by using a sol-gel method₂-SiO₂The C/C composite material with the SiC coating can uniformly and densely cover the C/C composite materialThe composite material greatly improves the oxidation resistance of the C/C composite material, and is a coating material with high quality.

The invention provides a method for preparing high-performance ZrO₂-SiO₂The method for preparing the-SiC ternary composite coating mainly comprises the following steps:

step (1) preparing SiO₂Sol, ZrO₂Mixing the sol according to a certain molar ratio, and magnetically stirring for a certain time at room temperature.

Step (2) soaking a SiC coating C/C composite material sample prepared from MTES sol with a certain mass fraction in ZrO at normal pressure₂-SiO₂In the sol, when no obvious air bubble escapes from the surface of the sample, the sample is placed in an oven with a certain temperature for drying for a certain time, and the steps are repeated.

And (3) putting the C/C composite material sample into a graphite crucible, putting the graphite crucible into a high-temperature carbonization furnace, taking high-purity nitrogen as protective atmosphere, controlling the temperature rise rate of the carbonization furnace, raising the temperature of the carbonization furnace from room temperature to a certain temperature, keeping the temperature for a period of time, and preparing ZrO₂-SiO₂-a SiC coating.

2. The method according to claim 1, wherein in step (1) Zr is selected: zirconium-silicon mixed sol with Si ratio of 4; stirred magnetically at room temperature for 1.5 h.

3. The method according to claim 1, wherein the step (2) is to select MTES sol with the mass fraction of 7% to prepare the SiC coating; the sample was dried in an oven at 80 ℃ for 2 h.

4. The method according to claim 1, wherein the step (3) of controlling the temperature rise rate of the carbonization furnace to 5 ℃/min, maintaining the temperature of the carbonization furnace at a constant temperature of 2 hours from room temperature to 900 ℃ and at a constant temperature of 1350 ℃ for 1 hour to obtain ZrO₂-SiO₂-a SiC coating.

5. High purity ZrO prepared by the process according to any one of claims 1 to 4₂-SiO₂the-SiC ternary mixed sol coating is characterized in that the coating can uniformly and compactly cover the C/C composite material, plays a certain role in protecting the C/C composite material and greatly improves the oxidation resistance of the C/C composite material.

The invention has the following advantages:

(1) the selected raw materials have low cost and wide sources, and the prepared sol has good stability.

(2) The sol-gel method is adopted to prepare the gel with low temperature and low energy consumption, and the microstructure of the gel is easy to control by changing conditions.

(3) The sol-gel method is adopted to improve the uniformity of a multicomponent system, so that ZrO₂-SiO₂the-SiC ternary mixed sol coating can be uniformly coated on the surface of the C/C material.

(4) The sol-gel method can be used for forming on a substrate with a large area or any shape, the thickness can be adjusted from a few nanometers to a micron, and the purity of the obtained product is extremely high.

(5) ZrO prepared by sol-gel method₂-SiO₂the-SiC ternary mixed sol coating can uniformly and compactly cover the C/C composite material, plays a certain role in protecting the C/C composite material, and greatly improves the oxidation resistance of the C/C composite material

Drawings

FIG. 1 shows the ZrO thus obtained₂-SiO₂Electron scan of-SiC ternary mixed sol coating.

Detailed Description

The present invention is illustrated by way of specific examples, but is not intended to be limited thereto. SiC coating and ZrO which have been prepared in the examples below₂-SiO₂Preparing ZrO from sol by sol-gel method₂-SiO₂-SiC ternary hybrid sol coating.

Example 1:

SiO to be prepared₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 80: 20 and mixed and stirred magnetically for 1.5h at room temperature. Then soaking a SiC coating C/C composite material sample prepared from MTES sol with the mass fraction of 7% in ZrO at normal pressure₂-SiO₂In the sol, when no obvious bubbles escape from the surface of the sample, the sample is placed in an oven at 80 ℃ for drying for 2h, and the steps are repeated. Placing the C/C composite material judgment sample into a graphite crucible, placing the graphite crucible into a high-temperature carbonization furnace, taking high-purity nitrogen as protective atmosphere, and controlling the temperature rise rate of the carbonization furnace to be 5 ℃/minHeating the furnace temperature from room temperature to 900 ℃ and keeping the temperature for 2h, and keeping the temperature for 1h at 1350 ℃ to prepare ZrO₂-SiO₂-a SiC coating. The coating is oxidized for 1 hour at the medium temperature in the air at the temperature of 1000 ℃, and the mass loss rate is about 9.3 percent.

Example 2:

mixing SiO₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 0: 100, and the other conditions are the same as those of the example 1, so that the prepared C/C mixed coating material cannot well protect the C/C composite material.

Example 3:

mixing SiO₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 20: 80 and the other conditions are the same as those of the example 1, and the prepared C/C mixed coating material cannot well protect the C/C composite material.

Example 4:

mixing SiO₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 40: 60, and the other conditions are the same as those of the example 1, so that the prepared C/C mixed coating material cannot well protect the C/C composite material.

Example 5:

mixing SiO₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 50: 50, and the other conditions are the same as those of the example 1, so that the prepared C/C mixed coating material cannot well protect the C/C composite material.

Example 6:

mixing SiO₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 60: 40, and the other conditions are the same as those of the example 1, so that the prepared C/C mixed coating material cannot well protect the C/C composite material.

Example 7:

mixing SiO₂Sol, ZrO₂The sol is prepared by the following steps of Zr: si molar ratio 100: 0, and the other conditions are the same as those of the example 1, so that the prepared C/C mixed coating material cannot well protect the C/C composite material.

Example 8:

the sample of the C/C composite material was immersed in 1% MTES sol under normal pressure, and the mass change of the C/C composite material after immersion in the MTES sol was 4.30% under the same conditions as in example 1.

Example 9:

the sample of the C/C composite material was immersed in 3% MTES sol under normal pressure, and the mass change of the C/C composite material after immersion in the MTES sol was 16.10% under the same conditions as in example 1.

Example 10:

the sample of the C/C composite material was immersed in 5% MTES sol under normal pressure, and the mass change of the C/C composite material after immersion in the MTES sol was 24.00% under the same conditions as in example 1.

Example 11:

the sample of the C/C composite material was immersed in 9% MTES sol under normal pressure, and the mass change of the C/C composite material after immersion in the MTES sol was 30.30% under the same conditions as in example 1.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.