special ceramics properties and functions

The properties of special ceramic materials are determined by two factors. First of all, the material structure, the main chemical bond property crystal structure. They determine the properties of ceramic materials, such as high temperature resistance, semiconductor and insulation. Secondly, microstructure, including distribution, grain size, shape, pore size distribution, impurities, defects and so on. Ordinary ceramics are made of clay, feldspar and quartz by preparation and sintering. This kind of ceramics is hard in texture, does not oxidize and rust, is corrosion-resistant, does not conduct electricity, can withstand certain high temperature, has good processing formability and low cost, but its strength is relatively low. Generally, the highest use temperature is no more than 1200 ℃, which is widely used in electrical, chemical and other industries due to its large output and variety.

Silicon carbide powder for silicon carbide ceramics is made by powder metallurgy through reaction sintering or hot pressing sintering process. Silicon carbide ceramics are characterized by high temperature strength, good thermal stability, wear resistance and creep resistance. It is suitable for pouring metal nozzle, thermowell, gas turbine blade, bearing and other parts. At the same time, because of its high heat conduction capacity, it is also suitable for heat exchanger materials under high temperature conditions, and can also be used to make various pump sealing rings.

Silicon nitride ceramics are rich in raw materials and have good processability. It can be used to produce all kinds of size and precision components with low cost, especially those with complex shape, with higher yield than other ceramic materials. Silicon nitride ceramic has good resistance to temperature shock and high hardness. Its hardness is second only to diamond, boron nitride and other materials. When the working temperature is increased to 1370 ℃, the engine efficiency can be increased by 30%. At the same time, due to the increase of temperature, the fuel can be fully combusted, and the exhaust gas pollution composition can be greatly reduced, which not only reduces energy consumption, but also reduces energy consumption environmental pollution.

There are many kinds of other special ceramic materials. They have their own characteristics and can be made into various functional components. Lithium oxide ceramics are high temperature materials, talc ceramics are high frequency insulating materials, thorium oxide ceramics are dielectric materials, barium titanate ceramics are photoelectric materials, boride, nitride, silicide and other cermets are ultra-high temperature materials. Ferrite ceramics are permanent magnets, memory magnets, magnetic heads and other materials, rare earth cobalt ceramics are memory materials, semiconductor ceramics are sub sensitive elements, solar cells and other materials.

What is special ceramics? Special ceramics are also called modern ceramics, industrial ceramics, fine ceramics or high-performance ceramics, including special structural ceramics and functional ceramics, such as electronic ceramics, wear-resistant ceramics, piezoelectric ceramics, magnetic ceramics, capacitor ceramics, high-temperature ceramics, nano ceramics, metal ceramics, bioceramics, etc. High temperature ceramics are the most important in engineering, including oxide ceramics, boride ceramics, nitride ceramics and carbide ceramics.