As an excellent performance and high temperature materials, silicon carbide ceramics has been increasingly used in petrochemical, iron and steel metallurgy, machinery and electronics, aerospace, energy and environmental protection, nuclear energy, automotive, high temperature kiln and other industrial fields.
(1) Sealing rings, plain bearings
Pressureless sintered and reaction sintered dense silicon carbide materials, because of its excellent wear resistance, high thermal conductivity, high temperature and corrosion resistance, is the manufacture of sealing rings, plain bearings and friction protection bushings ideal materials. It can be processed into various shapes and sealing rings with high dimensional accuracy and surface finish, and used as mechanical seals in many harsh environments. For example, they are used in sealing devices and sliding devices of acid- and alkali-resistant pumps in the shipbuilding, chemical, metallurgical, petroleum and paper industries, and have been widely used because of their good airtightness and long service life. Take Sic sealing ring in automobile water-cooling pump face seal application as an example. Face seals mainly provide sealing at the rotating interface, preventing the liquid or gas on the sealing side from flowing to the other side. For water-cooled automotive engine circulating water pumps, the use of ceramic ring seals can avoid water leakage during pump rotation, and can realize both sealing and sliding at the same time. In the past, commonly used Al, O, ceramic manufacturing, but now using siC material, because SiC than Al.O, high hardness, wear resistance and good service life. Similar siC sealing ring in the automobile air conditioning compressor has also been applied.
(2) Bulletproof ceramics
Silicon carbide ceramics due to high hardness, low density, better protective properties and lower prices (compared with B, C ceramics), applied in bulletproof armor has – a certain competitive advantage. Its protective performance is better than Al2O3 ceramics, although slightly inferior to B, C ceramics (about B, C ceramics of 70% ~ 80%), but SiC ceramics manufacturing cost is much lower than B.C. At present, atmospheric pressure sintering SiC and reaction sintering SiC ceramic plate is particularly suitable for large amounts and protective armor can not be overly thick and heavy occasions. Such as the United States CERCOM, INC company prepared high hardness, high toughness and high Weibull modulus (four-point bending strength of 580 MPa, fracture toughness Kxc for 4.7 MPa ● m1/2, Weibull modulus m = 17) SiC ceramics is an excellent bulletproof material.
(3) Nozzle
In the petroleum industry, energy, environmental protection, space rockets and machinery manufacturing and other fields need to use a variety of nozzles, see Figure 8-13 (g). Silicon carbide ceramics than Al2O3 and SiN ceramics due to higher hardness and thermal shock resistance and excellent corrosion resistance, and therefore widely used. For example, the service life of SiC ceramics is 3.5 times longer than that of Al2O3 ceramics for sand blasting nozzles. Reaction sintering, pressureless sintering and recrystallization sic can be used as high temperature kiln burner nozzle and thermal power plant desulfurization nozzle for desulfurization.