Infrared high shield core-shell structure opacifying agent for SiO2 aerogel and preparation method of opacifying agent

Abstract

The invention relates to an infrared high shield core-shell structure opacifying agent for SiO2 aerogel and a preparation method of the opacifying agent, and belongs to the field of high temperature heat-insulating materials. The opacifying agent is a TiO2-coated SiC hollow core-shell structure ceramic microsphere, wherein the hollow size theta is 0.8-1.5 mu m, the thickness of a nuclear layer SiC is 0.1-0.2 mu m, and the thickness of a shell layer TiO2 is 0.1-0.3 mu m. The preparation method comprises the following steps: I, sequentially adding butyl titanate, polysilazane and divinyl benzene into fused paraffin, and magnetically stirring to obtain a uniform oil phase; dispersing an emulsifier in deionized water in an ultrasonic condition to obtain a uniform water phase; stirring the water phase and the oil phase at a high speed to uniformly emulsify; installing a condensating device, and carrying out a reaction on the emulsion in an oil bath pan; II, centrifugalizing, cleaning and drying the product obtained in the step I; III, sintering the dried product in an atmosphere furnace; and IV, uniformly mixing the sintered product with the SiO2 aerogel and pressing and forming. The core-shell structure ceramic beads are controllable in size, light in weight and high-temperature resistant, and the core-shell structure opacifying agent can effectively improve the anti-infrared shield performance of the SiO2 aerogel.

Description

technical field [0001] The invention relates to a size-controllable core-shell ceramic microsphere and a preparation method thereof, more specifically, to a method for SiO 2 The invention discloses an airgel infrared high-shielding core-shell structure sunscreen and a preparation method thereof, belonging to the field of high-temperature heat-insulating materials. Background technique [0002] SiO 2 Airgel is an amorphous lightweight material with a nanoporous structure, with a porosity as high as 99%, and has good thermal insulation properties. The thermal insulation materials prepared with it have the advantages of light weight, low thermal conductivity, and high strength. It can be used in important fields such as aerospace, construction, industry, transportation, etc. But pure SiO 2 Airgel is penetrable to infrared rays in the 2-8μm infrared band at high temperatures, and SiO 2 When the base insulation material is used for a long time above 800 °C, the internal nanop...

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Problems solved by technology

Among them, carbon black is a kind of infrared sunscreen agent used earlier, but it is easy to oxidize when encountering high temperature, and the use temperature is low; Al 2 o 3 The fibers of inorganic ceramic fibers are generally longer, which are often used to prepare fiber composite materials, and the shading effect is poor; SiC micropowder, potassium hexatitanate whiskers, and titanium dioxide and SiO 2 Airgel doping can significantly reduce the pure SiO 2 Infrared transmittance of airgel

However, these powders themselves have a high density, and they are prone to precipitation during the gelation process, causing uneven dispersion in the airgel, reducing the high-temperature radiation heat transfer shielding effect, and the sediment will also increase solid-phase heat transfer. Cause the airgel block to crack during the drying process, seriously affecting its performance

[0004] In the past few decades, the core-shell structure has been widely studied due to its special structure and unique photoelectric, magnetic, and catalytic properties. However, most research on the core-shell structure mainly focuses on catalytic performance, adsorption performance, and electrode materials applications, little research has been done on thermal aspects

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