Silica Aerogel And Its Applications In The Aerospace Sector

Aerogels are an extremely porous form of silica with a low bulk density and high surface area. This makes them a good thermal insulator. Additionally, they have many other interesting properties such as optical transparency in the visible spectrum (99%), a very low index of refraction, and the ability to retain and concentrate large amounts of matter [7]. This makes them useful in outer-space explorations for capturing hypervelocity particles from cosmic debris.

Silica Aerogel in Insulation can be produced using a variety of methods. One method involves the use of tetraethyl orthosilicate (TEOS), also known as waterglass, as the precursor. TEOS is nontoxic and inexpensive. However, the production process is complicated and requires a lot of manual labor. Another method uses a solvent such as methanol. However, this is not a sustainable process and the resulting material is often not as transparent.

A third technique involves the use of rice husk ash as the precursor. The resulting material is less expensive than TEOS and can be made without a lot of manual labor. The disadvantage of this approach is that the material loses its optical transparency when methanol is added to the mixture.

The use of methanol also affects the mechanical properties of the material. It can be improved, but it is still not as strong as a conventional silica gel. Another method of making stronger silica aerogel is to add a polymer to it. The polymer reinforces the silica nanostructure and improves its strength. Moreover, it also enhances the acoustical and thermal insulation properties of the material.

Several different applications for Silica Aerogel are being promoted in the aerospace sector. A number of experiments have been carried out to test its capabilities as a Cherenkov radiation detector. One such experiment involved the use of five aerogel thermal insulated covers that were placed on top of the Shuttle Get Away Special (GAS) payload canisters and equipped with a grid of hypervelocity particle capture cells.

The tests showed that the aerogels survived both launch and reentry without any damage or loss of function. Another important application is to use a silica aerogel to capture particles from a meteor or asteroid. This would allow scientists to study the makeup of these objects.

The most important problem faced by researchers is to increase the mechanical strength of silica aerogels to a point that it can be used in load bearing applications. The brittle nature of aerogels is due to the fact that they are composed of many small, tortuous, and interlocked particles in a fractal network. This network has many dead-ends and therefore impedes the flow of heat. To overcome this, researchers are working to incorporate a polymer into the aerogels to strengthen them. This should make them twice as strong as conventional silica gel. In addition to this, there are a variety of other techniques being developed for characterization and enhancing the mechanical properties of the material. These include ultrasonic testing, three-point bending, and atomic force microscopy.