Silicon powder is made of natural quartz (SiO2) or molten quartz (amorphous SiO2 after high temperature melting and cooling of natural quartz) by crushing, ball milling (or vibration, air grinding), flotation, pickling purification, high purity water treatment and other processes. Silicon powder is a kind of inorganic non-metallic material which is odorless and pollution-free. Because it has good temperature resistance, acid and alkali corrosion resistance, poor thermal conductivity, high insulation, low expansion, chemical stability, high hardness and other excellent properties, it is widely used in chemical industry, electronics, integrated circuit (IC), electrical appliances, plastics, coatings, advanced paint, rubber, national defense and other fields. With the rapid development of high-tech fields, silicon powder will also enter a new historical development period.
1. Classification by level
Silicon powder can be divided into: ordinary silicon powder, electrical grade silicon powder, electronic grade silicon powder, molten silicon powder, ultrafine silicon powder, "spherical" silicon powder.
1, ordinary silicon powder is mainly used for epoxy resin castable, potting material, welding electrode protective layer, metal casting, ceramics, silicone rubber, coating and other chemical industry.
2, electrical grade silicon powder is mainly used for ordinary electrical insulation casting, high voltage electrical insulation casting, APG process injection material, epoxy pot-sealing material, ceramic glaze and so on.
3, the main use of electronic grade silicon powder is mainly used for integrated circuits, electronic components of plastic sealing materials and packaging materials.
4, molten silicon powder Molten quartz powder (WG) the raw material used is natural quartz after high temperature melting, cooling amorphous SiO2, through the process of processing of micro-powder. The product has high purity, low thermal expansion coefficient, low internal stress, high moisture resistance, low radioactivity and other excellent characteristics.
Mainly used in large scale and very large scale integrated circuit for plastic sealing material, epoxy castable, potting material, and other chemical fields.
5, the main use of ultrafine silicon powder is mainly used in coatings, paints, engineering plastics, adhesives, Quay rubber, precision casting advanced ceramics.
6, "pellet" silicon powder "pellet" silicon powder selection of high-quality quartz ore, a kind of high strength, high hardness, inert spherical particles, its main component SiO2 content of more than 99.6%, density of 2.65, Mohs hardness of 7, fineness between 325 mesh to 5000 mesh, whiteness between 70-94, It has a reasonable and controllable particle size range, and the appearance is white powder.
High quality "pelleted" silica powder with extremely low oil absorption, mixing viscosity and friction coefficient. Its unique spheroidal structure, compared with other angular quartz powder (silicon powder), the powder has good fluidity, and the resting Angle formed by the powder accumulation is small, so it is dense when mixed with organic polymer materials, enhancing the strength of the body. Easy to disperse, uniform mixing, can significantly increase the fluidity of the material.
Mainly used in coating, epoxy floor, silicone rubber, etc., greatly reduce the cost, significantly improve the processing performance of mixed materials.
Second, use division
Silicon powder can be divided into: paint powder with silicon powder, epoxy floor with silicon powder, rubber with silicon powder, sealant with silicon powder. Electronic grade and electrical grade silica powder for plastic sealing material, precision ceramic silica powder 1, paint and coating silica powder mesh number: 600-2500 mesh whiteness: 70-94 degrees between hardness: 7 (Mohs hardness)
Oil absorption, low mixing viscosity, good dispersion and fluidity, small resting Angle formed by accumulation, friction resistance.
2, epoxy floor with silicon powder mesh number: 600-1250 whiteness: 70-94 degrees between hardness: 7 (Mohs hardness)
Low viscosity, good fluidity, good accumulation, easy compaction, easy to combine with epoxy resins. Compared with traditional silicon powder, the amount of epoxy resin can be saved.
3, rubber with silicon powder mesh: 1250-5000 mesh SiO2: >99.5% whiteness: >70-94 degrees hardness: 7 (Mohs hardness)
(1). Application in wear-resistant rubber products Wear-resistant rubber products include rubber sheets, tubes, belts, rollers, which require the rubber to have good permeability and strong bonding, the test results show that the mixed rubber filled with silicon powder fully reflects the unique properties of thin rubber, good permeability, good dispersion, strong bonding, etc. It is beneficial to rub the rubber on the canvas and enhance the adhesive strength between the film and the canvas, and the mechanical properties such as the breaking strength and deformation of the product are significantly improved, especially the wear resistance of rubber products.
2). Application in silicone rubber products very low water content, good insulation; The particle size is less than 5μm, and it has certain reinforcement performance.
4, sealant with silicon powder mesh: 1250 mesh SiO2: >99.5% whiteness: >80-94 degrees hardness: 7 (Mohs hardness)
The water content of the treated silicon powder is less than 0.1%, which can improve the bonding strength, yield value and shear dilution index of the colloid in the sealant. It has the effect of thickening, reinforcing, anti-tearing and anti-aging.
5, electronic and electrical grade plastic sealing material with silicon powder mesh number: 600-5000 mesh SiO2: >99.5% whiteness: >90 degrees hardness: 7 (Mohs hardness)
Quasi-spherical silicon powder used in epoxy resin insulating packaging materials can greatly increase the filling amount, reduce the viscosity of the mixed material system, improve the processing performance, improve the permeability of the mixture, reduce the expansion coefficient of the cured material and the shrinkage rate of the curing process, and reduce the thermal growth difference.
6, precision ceramics with silicon powder mesh: 5000 mesh SiO2: >99.7% whiteness: >92 degrees hardness: 7 (Mohs hardness)
Third, the production process can be divided into: crystalline silicon powder molten silicon powder cristobalite silicon powder active silicon powder.
1, crystalline silicon powder Crystalline silicon powder is the use of high grade natural quartz, through a unique iron-free grinding process production and processing, its color is white, pure quality. Because of its mature process, it has stable physical and chemical properties and reasonable and controllable particle size distribution. Crystalline silicon powder can be divided into high purity crystalline silicon powder, electronic grade crystalline silicon powder and general packing grade crystalline silicon powder. Scope of use of crystalline silicon powder.
2, molten silicon powder Molten silicon powder is the selection of high-quality natural quartz, through a unique processing process to form the powder, through high temperature treatment, its molecular structure arrangement from orderly arrangement to disorderly arrangement. Its color is white, high purity and has the following characteristics: very low coefficient of linear expansion; Good electromagnetic radiation; Stable chemical properties such as chemical corrosion resistance; Reasonable, orderly and controllable particle size distribution. Molten silicon powder is widely used.
3, cristobalite silica powder cristobalite silica powder is the selection of high-quality natural quartz, the use of unique technology and special processing of powder. The high purity silica obtained after high temperature calcination can stabilize the changed crystal structure through rapid cooling, due to its stable chemical properties, reasonable orderly and controllable particle size distribution. And is widely used.
4, Active silicon powder Active silicon powder through its unique process, the use of silane and other materials to modify the surface of silicon powder particles, enhance the hydrophobic performance of silicon powder, improve the mechanical, electronic and chemical characteristics of the mixture and filling system. The surface treatment of silicon powder particles is mainly to improve the performance of the filling system.
