Silicon carbide aerogel and preparation method thereof

An airgel and silicon carbide technology, applied in the field of airgel, can solve the problems of complicated purification treatment, harsh preparation conditions, and long cycle, and achieve the effects of simple and controllable process, stable physical and chemical properties, and low oxygen content

Active Publication Date: 2016-05-25
厦门纳美特新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most studied are mainly SiO2 aerogels and C aerogels, SiO2 2 When airgel and its composite materials are used above 800°C, the thermal insulation performance drops sharply, while C airgel is easily oxidized and invalidated when used in an air atmosphere >400°C
Both are difficult to meet the requirements of the increasing development of science and technology
CN103864076A discloses a SiO 2 The method for preparing SiC airgel from airgel as a template, CN102910926A discloses a bulk silicon carbide airgel material and its method, both of which use silicon source and carbon source to form a co-precursor, and then undergo high-temperature carbon heat Reduction reaction (1400-1500°C), the preparation conditions are relatively harsh, and the subsequent purification treatment is complex, long-term, and difficult, which also leads to a relatively low yield of silicon carbide airgel materials

Method used

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  • Silicon carbide aerogel and preparation method thereof
  • Silicon carbide aerogel and preparation method thereof
  • Silicon carbide aerogel and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] (1) 6.0gPCS (its infrared spectrum such as figure 1 Shown) powder is dissolved in 94.0g cyclohexane, the preparation concentration is 6.0% PCS solution; Add 6.0gDVB and 0.3g~Pt, stir well to form a homogeneous solution, then transfer to the polytetrafluoroethylene tank in the reaction kettle , and then transferred to a pressure reactor, and carried out hydrosilylation polymerization and crosslinking reaction at 150°C for a reaction time of 5 hours. After the reaction was completed, the reactor and materials were cooled to room temperature to obtain a precursor gel;

[0029] (2) Transfer the precursor gel to a supercritical drying kettle, first replace it with liquid carbon dioxide for 1-3 days, and then undergo supercritical drying (50°C, 20MPa) to obtain the precursor aerogel;

[0030] (3) Under an inert atmosphere, the precursor aerogel is kept at 200°C for 1h, and then heat-treated at 800°C (heating rate 2°C / min) for 1-3h to obtain amorphous SiC aerogel, which is tre...

Embodiment 2

[0033] The raw material PCS in Example 1 was changed to polycarbosilane PXCS containing heterogeneous elements (X includes elements such as aluminum, iron, yttrium), and following the above test process, silicon carbide airgel materials containing heterogeneous elements can be obtained for use in special field.

Embodiment 3

[0035] Preparation of SiC airgel material by drying under normal pressure: After the precursor gel obtained in Example 1 was sealed and aged, n-hexane was used as a replacement solvent to replace cyclohexane in the pores, and the replacement was performed 3 times for 24 hours each time. Then it is placed in a programmed temperature-controlled oven, and the drying program is as follows: heat up to 50°C (3°C / min) for 2 hours; heat up to 80°C (2°C / min) for 4 hours; heat up to 110°C (5°C / min) ) for 6 hours; natural cooling to obtain the precursor airgel, the subsequent steps are the same as in Example 1, and SiC airgel materials can also be obtained. SiC airgel porosity ~ 75%, specific surface area ~ 110m 2 / g.

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Abstract

The present invention discloses a silicon carbide aerogel, which is prepared from polycarbosilane containing Si-H bond, divinylbenzene, a Pt catalyst and an organic solvent by a polymer precursor conversion ceramic preparation method and aerogel preparation method. The silicon carbide aerogel has a specific surface area of 50-400 m<2> / g, a porosity of 70-90% and density of 0.1-0.2 g / mL; the mass ratio of polycarbosilane to divinylbenzene is 1:08-1.2; and the Pt catalyst accounts for 0.1-0.5% of the total weight of polycarbosilane and divinylbenzene. The method utilizes polymer precursor conversion ceramic preparation method for preparation of SiC aerogel, and the conversion temperature is as low as 800 DEG C. The obtained SiC aerogel has low oxygen content, high purity, good quality, and controllable porosity and density; and the process is simple and controllable.

Description

technical field [0001] The invention belongs to the technical field of airgel, and in particular relates to a silicon carbide airgel and a preparation method thereof. Background technique [0002] Airgel usually refers to a lightweight nano-solid material, a skeleton, in which nano-scale particles aggregate to form a nano-porous network mechanism. The particle diameter is 1-20nm, the pore size is 2-100nm, and the porosity is as high as 90%. The special structure makes it have the advantages of light weight and high-efficiency heat insulation at the same time, and can be widely used in the fields of heat, light, sound, electricity, mechanics, etc., and has attracted extensive attention from the scientific research and industry circles. One of the most promising materials in the century. At present, the most studied are mainly SiO2 aerogels and C aerogels, SiO2 2 When airgel and its composite materials are used above 800°C, the thermal insulation performance drops sharply, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/04C04B35/571C04B35/624
CPCC04B35/571C04B35/624C04B38/04C04B2235/483C04B2235/77C04B38/0045C04B38/0074C04B38/0067
Inventor 余煜玺陈勇
Owner 厦门纳美特新材料科技有限公司
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