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The Characteristics and Development History of Silicon Nitride

wallpapers Industry 2020-10-10
Silicon nitride is an inorganic substance with the chemical formula Si3N4. It is an essential structural ceramic material with high hardness, inherent lubricity, wear resistance, and atomic crystals; it is resistant to oxidation at high temperatures. Moreover, it can resist the impact of cold and heat. It will not be broken if it is heated to more than 1000℃ in the air, cooled rapidly and then heated rapidly. It is precisely because of the excellent characteristics of silicon nitride ceramic that people often use it to manufacture mechanical components such as bearings, gas turbine blades, mechanical seal rings, permanent moulds and so on. If silicon nitride ceramics, which are resistant to high temperatures and difficult to transfer heat, are used to make the heating surfaces of engine components, not only can the quality of the diesel engine be improved, fuel savings and thermal efficiency can be improved. China, the United States, Japan and other countries have developed such diesel engines.
 
Henry Edin St. Clair Deville and Friedrich Weiler first reported the synthesis of silicon nitride in 1857. In the synthesis method, they said, another crucible filled with silicon was buried in a crucible filled with carbon and heated to reduce the infiltration of oxygen. They reported a product they called silicon nitride, but they could not figure out its chemical composition. In 1879, Paul Schuetzenberger mixed silicon with a lining material (a paste that can be used as a crucible lining, obtained by blending charcoal, coal or coke and clay) and heated it in a blast furnace, and reported it as a component. It is a compound of Si3N4. In 1910, Ludwig Weiss and Teodor Engelhardt heated silicon element under pure nitrogen to obtain Si3N4. In 1925, Friederich and Sittig used carbothermal reduction method to combine silicon dioxide and carbon in a nitrogen atmosphere. Heat to 1250-1300℃ to synthesize silicon nitride.
 
In the following decades, until the commercial use of silicon nitride appeared, silicon nitride was not paid attention to and studied. From 1948 to 1952, Acheson founded the Emery Company near Niagara Falls, New York, and registered several patents for the manufacture and use of silicon nitride. In 1958, the silicon nitride produced by Union Carbide was used to make thermocouple tubes, rocket nozzles and crucibles for molten metal. British research on silicon nitride began in 1953, with the purpose of manufacturing high-temperature parts for gas turbines. This led to the development of bonded silicon nitride and hot-pressed silicon nitride. In 1971, the Defense Advanced Research Projects Agency under the US Department of Defense signed a $17 million contract with Ford and Westinghouse to develop two ceramic gas turbines.
 
Although the properties of silicon nitride have long been well known, the silicon nitride (approximately 2×5µm in size) that exists in the natural world of the Earth was only discovered in meteorites in the 1990s. To commemorate the pioneer of mass spectrometry research, Alfred Otto Carl Neal named this type of silicon nitride ore found in nature "nierite". However, there is evidence that this type of silicon nitride ore may have been found in meteorites in Azerbaijan in the former Soviet Union earlier. Meteorites containing silicon nitride minerals have also been found in Guizhou Province, China. In addition to meteorites that exist on Earth, silicon nitride is also distributed in cosmic dust in outer space.


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Tag: Silicon Nitride