Something about silicon
Silicon is a chemical element, the English name Silicon, the chemical symbol is Si, the old name is silicon, the atomic number is 14, the relative atomic mass is 28.0855, the density is 2.4g/cm³, the melting point is 1414°C, the boiling point is 2355°C, and it belongs to the IVA group on the periodic table.metal element.Silicon has two allotropes, crystalline silicon and amorphous silicon. Crystalline silicon is steel gray and amorphous silicon is black. Crystalline silicon is an atomic crystal, hard and shiny, and has semiconductor properties.The chemical properties of silicon are relatively active. It can combine with oxygen and other elements at high temperatures. It is insoluble in water, nitric acid and hydrochloric acid, but soluble in hydrofluoric acid and lye.Silicon is widely distributed in nature, and generally rarely occurs in the form of simple substances, mainly in the form of silicon dioxide and silicate. The crust contains about 27.6%, which is the second most abundant element in the crust after oxygen.Mainly used to make high-purity semiconductors, high temperature resistant materials, optical fiber communication materials, organic silicon compounds, alloys, etc., are widely used in aerospace, electronic and electrical, construction, transportation, energy, chemical, textile, food, light industry, medical, Agriculture and other industries.
High purity semiconductor
High-purity monocrystalline silicon is an important semiconductor material. It can be made into diodes, triodes, thyristors and various integrated circuits (including chips and CPUs in people's computers), and it can also be made into solar photovoltaic cells to convert radiant energy into electrical energy.In 2012, China has surpassed Europe and Japan to become the world's largest producer of solar cells.
High temperature resistant materials
Silicon can be used to make metal-ceramic composite materials. This material inherits the respective advantages of metal and ceramics, while also making up for the shortcomings of the two. It has the advantages of high temperature resistance, high toughness, and cutting ability.The first space shuttle "Columbia" relied on the shell built of silicon tiles to withstand the high temperature generated by friction when the aircraft passed through the dense atmosphere at high speed.
Optical fiber communication materials
The organic compound of silicon combines the excellent inorganic properties of silicon with the properties of organic materials, making the organic silicon compound unique and opening up new areas.It has the basic properties of low surface tension, low viscosity-temperature coefficient, high compressibility, high gas permeability, etc., and has high and low temperature resistance, electrical insulation, oxidation stability, weather resistance, flame retardancy, water repellency, corrosion resistance, and noToxic, odorless, and physiologically inert, and other excellent characteristics, mainly used in sealing, bonding, lubrication, coating, surface activity, demoulding, defoaming, foam suppression, waterproof, moisture-proof, inert filling, etc.With the continuous growth of the number and variety of silicones, and the continuous expansion of application areas, silicones have become a unique and important product system in the field of new chemical materials. Many silicones are irreplaceable and indispensable for other chemicals.
According to their different forms, silicone materials can be divided into: silane coupling agent (silicone chemical reagent), high temperature vulcanized silicone rubber, liquid silicone rubber, silicone oil (silicone grease, silicone emulsion, silicone surfactant), silicone resin, compositeThings etc.For example, organic plastics can be made into waterproof fabrics with excellent performance. Silicone sprayed on the four walls of the subway can solve the problem of water seepage. The surface coatings of ancient cultural relics and sculptures are also organic silicon compounds.Silicone oil can be made into a good lubricant.Silicone rubber can be used as an insulating material as well as a medical polymer material. Affected by the distribution and demand of my country's textile, electronics, medical, daily chemical and other terminal industries, silicone rubber occupies half of the downstream products of organic silicon.
Relying on its better characteristics, silicone rubber has gradually been accepted by the product industry and has gradually become popular rubber in some areas. With the development of the terminal industry in recent years, silicone oil, the second largest product of silicone, has also received more and more attention.Attention, in the textile, electronics, papermaking and other fields, silicone oil has become an indispensable force for the production of high-quality products. It is estimated that in 2015, the apparent consumption will reach 360,000 tons, an increase of 44%. Silicone oil is in the downstream products of organic silicon.The proportion of China will tend to developed countries such as Europe and the United States.
In the process of sustainable development of downstream products in my country's organic silicon industry, the development potential of silicone rubber has gradually stabilized, while silicone oil and silane coupling agents will become the key development directions of downstream products with strong continuity.
For a long time, the largest downstream product of organic silicon in my country is silicone rubber, and the largest end application field of silicone rubber is the construction industry. This structure will continue in the short term. In the past two years, my country’s real estate industry has developed rapidly. The demand for silicone products is increasing year by year.At the end of the two sessions in 2014, the impact of the new-type urbanization began to manifest.
The National New-type Urbanization Plan (2014-2020) was released under the authorization of Xinhua News Agency.The plan puts forward development goals, that is, "the urbanization rate of the permanent population will reach about 60%, and the urbanization rate of the registered population will reach about 45%."In recent years, more and more organic silicon companies have begun to pay attention to the high added value of products and the research and development of new products. In various high-end fields, such as medicine and fine electronics, organic silicon products have begun to be applied.The degree of dependence on the market has begun to weaken, and with the continuous improvement of technology, the proportion of late-stage silicone products in the high-end industry will become larger and larger.
Silicon alloy
The presence of silicon in the silicon aluminum alloy can improve the fluidity of the alloy, reduce the tendency of hot cracking, reduce porosity, and improve air tightness.This kind of alloy has good corrosion resistance and medium machining performance, has medium strength and hardness, and has low plasticity. It is used to manufacture low and medium strength castings with complex shapes, such as cover plates, motor housings, and brackets.And so on, also used as brazing solder.
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