Aerogels Are Produced In A Variety Of Forms
Silica Aerogel is a gel-like material with an extremely low density, thermal conductivity and refractive index. It exhibits remarkable physical properties and has been used for various applications in high-tech fields such as acoustics, fire protection and kinetic energy capture. Silica Aerogel is an excellent thermal insulation material, capable of reducing the transmission of heat to adjacent materials by a factor of 100 compared to conventional insulations such as cellular foam or mineral wool. In fact, it is the material of choice for insulating cryogenic spacecraft and the interior of the ISS.
However, despite its incredible thermal properties, the current technology is limited by poor mechanical strength. The brittleness of the interparticle connections in the gel network renders it inapt for load bearing applications. Nonetheless, the elasticity of silica aerogel can be improved by cross-linking and the use of various polymers. This is particularly crucial in aerospace applications such as protective shields and cladding for small satellites, spacecraft, and planetary vehicles.
Currently, silica aerogel is produced using a supercritical drying process which is expensive and labor intensive. This limits the mass production of the material for various applications. Moreover, the toxicity of the raw material (tetraethyl orthosilicate) imposes stringent safety standards for synthesis. The use of a new raw material, tetraethyl borosilicate (TEOS) has made the process less hazardous but has not yet reached the stage of commercialization.
The TEOS-based aerogel is currently manufactured Silica Aerogel in Insulation , Custom Materials, Inc. These companies produce blocks and granules as well as flexible blankets. They are also active in research and development activities. In order to reduce the cost of production, it is important to develop new preparation methods to replace the supercritical drying method and improve the mechanical properties of silica aerogels.
In addition to its excellent thermal performance, the unique chemical composition of silica aerogel makes it an incombustible and non-toxic material that can prevent fire from spreading to other components in the aerospace sector. The fire protection capabilities of the aerogel allow it to be a viable alternative to existing combustible coatings that release toxic fumes on combustion. Using aerogel blankets for insulating the pipes, wires and electronic accessories within the hot zones of an aircraft will significantly save weight and space compared to traditional metal sheets.
In addition, the inorganic nature of aerogel can help to reduce the fire risks caused by lithium ion batteries in an aircraft. The thermal insulation capability of the aerogel can help to lower the temperatures inside the battery compartment preventing damage and short circuits caused by overheating. This will enable better management of power generation, resulting in significant savings for the airlines. Furthermore, the thermal insulation capacity of aerogel will allow them to operate at higher temperature ranges for longer periods of time, increasing the efficiency and lifespan of lithium ion batteries. This will contribute to the overall improvement of aircraft fuel economy and reduce carbon emissions.