Fibers to the world: heavy-duty material will allow the creation of new generation spaceships

Russian scientists have created a new generation of carbon fiber material with record thermal conductivity and zero thermal expansion. It is able to withstand heavy loads and extreme temperature changes. Its implementation will open up prospects for the creation of next-generation spacecraft, as well as orbital telescopes, solar sails and cooling surfaces of nuclear power plants. The development is based on mesophase pakes (a product of the coal industry), which, with a certain processing algorithm, turn into almost perfect crystals.

Material for space and nuclear technologies

In Russia, scientists from the Rosatom Chemical Technology Cluster have developed innovative carbon fiber for strategic industries. Its material is highly rigid, does not deform under load, and does not change shape under extreme temperature fluctuations.

As the developers explained, such qualities make it promising for next-generation spacecraft and technology. In particular, the new fiber will be in demand when creating structures made of polymer composites with dimensions of about 200 m (like two football fields) and more.

For example, it will be possible to use it to make solar sails for interstellar travel, huge radio telescopes and antennas for exploring deep space, as well as grandiose reflectors for orbital power plants. They will be able to capture the energy flow from the Sun and transmit it to Earth using a laser or microwave radiation.

— The new filaments also have one of the highest thermal conductivity values. This will make it possible to create structures that can quickly "take" heat from hot parts and remove it by radiating from a large surface. This is the only way to cool in space, so the development will be useful when creating powerful power plants," Artur Gareev, Deputy Director for Science and Innovation of the Rosatom Chemical Technology Cluster, told Izvestia.

The new carbon fiber will be in demand in various descent vehicles that experience extreme temperature overloads when entering the dense layers of the Earth's atmosphere and a number of other planets, he added. Thus, the material can effectively dissipate heat from the heated surface to cold areas.

Other applications of the development include the enrichment process in centrifuges, where high-modulus fiber will help keep machine elements from collapsing at tremendous rotational speeds, added Artur Gareev. In addition, lightweight and super-rigid filaments will find application in aircraft structures that experience the greatest stresses when creating lift and during flight.

— Fibers are made from mesophase pitch. It is a complex mixture of polycyclic aromatic hydrocarbons. Such raw materials are obtained from coal tar, a viscous liquid that is formed during coking (heating without air access) of coal," explained Andrey Karpov, head of the carbon—carbon composite Materials Department of the cluster.

According to him, the hydrocarbon molecules in the resin are ordered when the temperature increases to 300-500 ° C and high pressure, forming a liquid crystalline phase — a mesophase. At the same time, structures arise in it that are involved in the formation of carbon fiber.

How to create carbon fiber with unique properties

Production begins with the pulling of filaments from a mesophase pitch. Then comes the oxidation, when the fibers are stabilized so that they do not melt during further processing. Next, carbonation occurs, which is the heating of the material in an oxygen—free environment, which leaves almost pure carbon structures, the specialist explained.

This is followed by processing at temperatures up to 2500-3000 ° C (graphitization), while to orient the graphene layers, the fiber is subjected to stretching, as a result of which the atoms are arranged in a perfectly ordered lattice. At this stage, the material acquires its own unique properties.: high coefficient of thermal conductivity, close in values to the theoretical limit for crystalline carbon, high modulus of elasticity (stiffness) and mechanical strength.

— Graphene layers, which form the basis of carbon materials, can combine into crystal structures. Based on their size and orientation, it is possible to obtain materials with different properties. For example, with a certain crystal orientation, carbon fibers will have maximum strength in a given direction," explained Egor Danilov, head of the cluster's Functional Materials Department.

In addition, he added, carbon fibers can be obtained from various starting materials (including wood, and products of coal and oil processing), which is of great importance for the industry.

Currently, the production technology of the new material is at the stage of laboratory testing, noted Artur Gareev. In order to reach industrial volumes, investors and partners are needed, while the development potential is huge, he added. According to him, carbon fiber is currently in demand in the domestic space industry, and when creating lunar bases, nuclear tugboats and other equipment, which now seems fantastic, the need for a new material will increase significantly.

— The development of composite materials based on high—modulus carbon fibers is one of the most promising areas in modern materials science. Carbon fibers, which have record—breaking specific strength and rigidity, when combined with innovative matrices, such as ceramics or metal alloys, make it possible to create functional materials that surpass their traditional counterparts in resistance to deformation, wear and extreme temperatures," Mikhail Maslov, Professor of the Department of Condensed Matter Physics at the National Research Nuclear University MEPhI, commented on the development.

According to him, the key factor of progress in this area is the development of nanoengineering methods that allow controlling the orientation and density of fiber laying, as well as creating hybrid materials by embedding nanoparticles (for example, graphene, carbon nanotubes) or binding to polymer matrices at the molecular level.

The expert noted that heavy-duty and highly heat-conducting carbon composites are in demand where high mechanical stress is combined with strict heat dissipation requirements. In addition to the above-mentioned applications, these can be, for example, blades of wind turbines and components of hydrogen infrastructure and powerful laser systems. As well as new-generation electronics, where the composite is able to simultaneously play the role of a bearing part and a thermal radiator, which will significantly reduce the mass and increase the life of the devices.

— The significance of the development lies in the fact that it is now possible to create lightweight, durable, stable structures in space conditions. This is important because in space, on one surface of a thin sheet illuminated by the Sun, the temperature can be +170°C, and on the shadow surface -170°C. This leads to a "warping" of the product if its coefficient of linear expansion is not zero," said Andrey Stepashkin, senior researcher at the NUST MISIS Center for Composite Materials.

According to him, the fact that Russia has developed a domestic technology for the production of carbon fibers based on mesophase pitches is a great achievement, since up to now such fibers have been purchased abroad, and sanctions have seriously hampered this process.