Researchers Develop Method to Make Extreme Heat Resistant Carbon Composite
Researchers at Oak Ridge National Laboratory have developed a novel process to produce extreme heat-resistant carbon-carbon composites.
Carbon-carbon composites, or reinforced carbon-carbon, are basically carbon fibers based on carbon precursors and carbon nano-tubes embedded in a carbon matrix. Every engineer loves it for its extraordinary mechanical properties such as the extremely high strength combined with almost unbelievable lightness.
Although these composite materials can retain their properties even at 2000 OC (3632 OF), in some very demanding applications such as aerospace, this is not enough. The solution of using protective coatings to prevent oxidation and allow the carbon-carbon composite to reach higher temperatures can only do so much, and also increases the density of the material.
The researchers followed a different experimentation approach, using a pure graphite matrix instead of epoxy to bind the fibers. Epoxy is the source of the problem when it comes to heat, as taking up too much thermal energy causes the material to shrink and the composite piece to deform.
To avoid using epoxy, the scientists deployed additive manufacturing and fused deposition modeling. This has significantly cut the production time, and by extension, the costs of producing such exotic composite materials.
Additionally, pyrolysis fuel impregnation and oil-derived mesophase binder pitches were used in order to achieve oxidative stabilization and increase the density and mechanical properties of thick carbon-carbon composites.
The team manufactured a nose cone and fins that feature embedded temperature sensors and sent their prototype to the U.S. Navy that will test the piece on a NASA rocket test launch. As the leader of the researchers stated, this launch will enable them to collect data, measure temperatures, and evaluate the performance of the material under extreme conditions. If the results are positive, it’ll be a huge step for materials of this kind to finally find a more omnipresent place in high-speed flight and aerospace engineering in general.