SIC materials are critical for improving aero-engine performance
Recently, ZGDK revealed to the public that they have made a breakthrough in the research of large-diameter silicon carbide (SIC) single crystal growth and realized the mass production of high-dimensional SIC powder, marking that China has made great progress in this material field.
SIC single crystal is considered to be one of the most widely used new materials. Its biggest feature is stable performance, excellent heat resistance and wear resistance, which makes this material widely used in machinery, electronics and other fields. It is a national defense construction and national One of the key materials urgently needed by the economy.
The most concerned use of SIC materials is the use in engines, especially aero engines. The design requirements of aero engines are to use lighter weight and provide greater thrust, and to achieve this goal to increase the working temperature of the engine, which is what we often hear. The temperature before the turbine, but increasing the temperature before the turbine means that the material must have better high temperature resistance, which will reduce the cooling requirements for the engine, simplify the engine structure, and reduce the weight. It is generally believed that the weight of the engine is 1 kg, and the weight of the aircraft will be reduced by 3 kg. If the material is not good enough, complex cooling methods need to be used. As a result, the engine structure will be more complicated, and the weight will increase. The increase in the weight of the engine will lead to a further increase in the weight of the aircraft. The contribution of high-temperature materials to the engine and the aircraft can be imagined.
Aero-engines work in high temperature, high speed and high pressure environments, and have higher requirements for materials
The LEAP engine uses a SIC-based ceramic matrix composite material, which successfully reduces the weight of the engine, thereby reducing the empty weight of the aircraft
The tail nozzle of F414 also uses SIC material
Judging from the research progress of aero-engine at home and abroad, metal high-temperature materials have approached the limit, and the future development focus is on ceramic matrix composites (CMC). CMC materials use fiber toughness to make up for the fragile shortcomings of ceramic materials. As mentioned earlier, SIC materials have excellent High temperature resistance, wear resistance and other properties, so among the ceramic matrix composite materials, SIC materials are the most concerned. At present, CMC materials have been used in aero-engines abroad. For example, the new generation of LEAP turbofan engines use CMC materials, so that the engine The weight is reduced by hundreds of kilograms, which in turn reduces the structural weight of the aircraft by nearly 1 ton, which greatly improves the economic performance of the aircraft. It can be said that the effect is remarkable. Tracking research has also been carried out in this field in China, and turbine blades based on CMC materials have been completed. According to relevant information, the weight of turbine blades based on CMC material is reduced by about 70% compared with metal turbine blades, which can effectively improve engine performance.
In addition to engine blades, CMC materials can also be used in other parts of the engine, such as fuel chambers, tail nozzles, etc., and can also be laid on the surface of aircraft as a heat-resistant layer to prevent aerodynamic heating from causing the body temperature to rise, which is detrimental to the aircraft structure. influence.
SIC is also widely used in the field of new generation electronic materials
The substation system of the Ford-class aircraft carrier adopts SIC-based electrical components
The application field of SIC is not only limited to the mechanical field, but also has a wide range of applications in the semiconductor field. Traditional silicon-based (SI) materials have poor high temperature resistance. It is generally believed that the operating temperature of SI-based integrated circuits cannot exceed 250 degrees. , With the improvement of the performance requirements of electronic equipment, the performance requirements for equipment power, voltage, environment, etc. are also getting higher and higher, and the performance of SIC materials is much better than that of SI materials, for example, the withstand voltage is 10 times that of the latter, and the The energy band spacing is 2.8 times that of silicon (wide band gap), reaching 3.09 electron volts. Its dielectric breakdown field strength is 5.3 times that of silicon, and its thermal conductivity is 3.3 times that of silicon, so it is more suitable for the production of radiation-resistant, high-frequency, high-power and high-density integrated electronic devices. It is reported that the US Ford-level substation system uses SIC-based devices, thereby reducing the size and weight of the equipment by about 50%.
To sum up, we can see that China has made breakthroughs in SIC materials, which has laid a solid foundation for the improvement of the performance of domestic engines and electronic equipment.