Introduction to Silicon Carbide Ceramics
SiC ceramics not only have excellent room temperature mechanical properties, such as high bending strength, excellent oxidation resistance, good corrosion resistance, high wear resistance and low friction coefficient, but also high temperature mechanical properties (strength, creep resistance etc.) is the best among known ceramic materials. The high-temperature strength of hot-press sintering, pressureless sintering, and hot isostatic pressing sintering materials can be maintained up to 1600°C, making them the best high-temperature strength among ceramic materials. Oxidation resistance is also the best among all non-oxide ceramics. Also known as emery.
Silicon carbide (SiC) is a compound with strong covalent bonds. The ionic form of its Si--C bond is only about 12%. Therefore, it also has excellent mechanical properties, excellent oxidation resistance, high wear resistance and Low coefficient of friction, etc. The biggest feature of silicon carbide is its high high temperature strength. The strength of ordinary ceramic materials will be significantly reduced at 1200 ~ 1400 degrees Celsius, while the flexural strength of silicon carbide still maintains a high level of 500 ~ 600MPa at 1400 degrees Celsius, so its working temperature It can reach 1600 ~ 1700 degrees Celsius. In addition, silicon carbide ceramics have high thermal conductivity, second only to beryllium oxide ceramics among ceramics. Therefore, silicon carbide has been widely used in high-temperature bearings, bulletproof plates, nozzles, high-temperature corrosion-resistant components, and electronics in high-temperature and high-frequency ranges. Equipment parts and other fields.
SiC ceramics have excellent mechanical properties, excellent oxidation resistance, high wear resistance and low friction coefficient. The disadvantage of SiC ceramics is low fracture toughness, that is, high brittleness. For this reason, complex phase ceramics based on SiC ceramics, such as fiber (or whisker) reinforcement, heterogeneous particle dispersion strengthening, and gradient functional materials have appeared one after another. , improving the toughness and strength of the single material.
The initial application of SiC was due to its superhard properties, which can be prepared into various grinding wheels, emery cloths, sandpapers and various abrasives, so it is widely used in the mechanical processing industry. During World War II, it was discovered that it could also be used as a reducing agent and heating element in steelmaking, thus promoting the rapid development of SiC. SiC ceramics have been widely used in industrial fields such as petroleum, chemicals, microelectronics, automobiles, aerospace, aviation, papermaking, lasers, mining and atomic energy. Silicon carbide has been widely used in high-temperature bearings, bulletproof plates, nozzles, and high-temperature corrosion-resistant components. As well as electronic equipment components in high temperature and high frequency ranges.