Heat Shielding
A heat shield is designed to shield some part of equipment from absorbing excessive heat from an outside source by either dissipating, reflecting or simply absorbing the heat.
Due to the large amounts of heat given off by internal combustion engines, especially exhausts, heat shields are used on most engines to protect components and bodywork from heat damage.
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Heat shielding gold foil |
Heat shielding flexible aluminium heat shield with ceramic thermal coating |
Heat shields vary widely in price. In Formula 1, the rigid heat shield are made out of aluminium or gold sheet or other composites, with a ceramic thermal barrier coating to improve the heat insulation. High performance flexible heat shields sometimes include extras, such as ceramic insulation applied via plasma spraying.
Most used is gold sheet, and we can see it very often on lower wing element or covering rear suspension wishbones to protect them from heat from exhaust. As heat shielding, apparently very, very thin layers will effectively reflect radiant heat with almost no mass, needing only to be a few atoms thick to do the job, and gold's extreme malleability allows making these thin foils.
Road car fans will recall that BMW used gold-sheet heat shielding in the installation of the 6l V-12 used in the McLaren F1 road car. Gordon Murray elected to line almost the entire engine bay of the McLaren F1 with gold cladding because of its superior reflectivity and thermal diffusivity.
But as we can see in case of RedBull and Ferrari cars, in area around low exhaust bodywork with blown diffuser, no gold foil can be seen (with exception of wishbones). Modern technology offer other solution when structural integrity and strength is needed. Strange material is called „PyroSyc“, and is invention of „Pyromeral Systems“.
After 10 years of development, Pyromeral Systems has introduced an entirely new generation of materials that finally brings the advantages of composites to the world of high temperatures. With this technology, it is now possible to design and manufacture lightweight composite parts used at high temperatures that not only provide an excellent level of thermo-mechanical performance, but also remain easy and affordable to produce.
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Hybrid composite material: |
These new composite materials, marketed under the PyroSic® and PyroKarb™ names, are based on proprietary glass-ceramic matrix systems reinforced with silicon carbide or carbon fibers. Thanks to the use of advanced inorganic polymers, they are processed at low temperatures with the same techniques and tooling as those used for conventional carbon-fiber reinforced plastics (CFRP). 
Yet, they also offer a much improved resistance to heat and fire, as they retain good mechanical properties at temperatures for which CFRP cannot even be considered (typically, up to 1000°C/1800°F). Material is lightweight, especially compared to metals like steel, inconel or titanium, have an excellent resistance to long term exposure up to 1000°C (1800°F) depending on the reinforcement, is compatibility with applications requiring good mechanical strength and resistance to vibrations, have dimensional stability at high temperatures. However this material is not permitted by FIA technical regulation to be used like exhaust building material. During 2011 preseason testing Ferrari wanted to produce the exhaust in glass ceramic composite (such as PyroSic), but this request was denied by technical delegate Charlie Whiting who clarified the exhaust must be made of materials on the permitted materials list. Such composites, while allowed to be used in some other areas, are not allowed to be the actual material of the exhaust pipe.
PyroSic materials are glass-ceramic matrix composites based on inorganic thermoset polymers. The glass-ceramic matrices specifically feature a glassy phase containing silicon oxide nanoparticles. These matrices are derived from geopolymeric systems and inherently resistant to heat and fire.
Applications for PyroSic and PyroKarb include heat shields, exhaust ducts, pipes for hot fluids or gases, fire barriers and other structural components. The materials are typically used in the field of motorsports, aerospace, defense, naval or automotive, either as a replacement of metals for weight reduction purposes, or as a replacement/complement for CFRP for improved thermal stability.
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