According to the creators, they have succeeded in simultaneously increasing the melting point, thermal conductivity and oxidation resistance, as well as reducing the density of the material and energy costs of its production. Their study results were published in the Ceramics International journal.
Rocket and space equipment must be able to withstand intensive loads at temperatures above 2000 °С when passing through the Earth's atmosphere. According to scientists, heat protective coatings made of composite materials are used in the production of these elements.
‘Structural Ceramic Materials’ Research Center
© Photo : NUST MISIS
However, the materials must also be able to withstand intense oxidation under such conditions. Therefore, the most common carbon-carbon composites are not used at temperatures above 1600 °C as oxidation becomes uncontrollable beyond this temperature: the active oxygen ingress and product formation from the gas-phase reactions leads to the coating’s complete burnout.
Dmitry Moskovskikh, head of the ‘Structural Ceramic Materials’ Research Center
© Photo : NUST MISIS
A scientific team from the NUST MISIS Research Center “Structural Ceramic Materials” comprised of Veronika Suvorova, Andrey Nepapushev and Dmitry Moskovskikh has developed a new composite material based on hafnium carbonitride, which is resistant both to high temperature and oxidation.
“Our proposed composite not only possesses high oxidation resistance at temperatures above 2000 °С, but also has high mechanical and thermophysical properties. The addition of silicon carbide has increased the oxidation resistance and reduced the density of the material by almost half without reducing its mechanical properties,” said Moskovskikh, who is head of the Research Center.
According to him, their material can be applied during the production of the critical assembly units of the rocket-space and other perspective equipment. The segments of the constructions made of the new composite will provide effective heat protection in the points of full flow braking that experience the highest thermal load, the creators explained.
Andrey Nepapushev, senior researcher of the ‘Structural Ceramic Materials’ Research Center
© Photo : NUST MISIS
The scientists explained that they have synthesized hafnium carbonitride by burning a mixture of hafnium and carbon in a nitrogen atmosphere, and used spark plasma sintering to produce the volumetric material. According to the researchers, this method provides a simple, fast and energy-efficient approach that is suitable for industrial production.
The study was carried out within the framework of the Russian Science Foundation (RSF) Grant No. 19-79-10280. At the next stage, the research team intends to work out the production technology from the new composite of various construction elements operated in high-speed gas flows.