Yuan Lei's Little Knowledge | Spherical Silicon Micropowder of Silicon Micropowder Series
Spherical silica powder, also known as spherical quartz powder, refers to the amorphous quartz powder material with spherical particles and silica as the main component. It is widely used in large-scale integrated circuit packaging in copper clad laminate and epoxy plastic filler, aerospace, fine chemicals and daily cosmetics and other high-tech fields.
01, spherical silicon powder preparation method.
There are physical and chemical methods for preparing spherical silica powder. Physical methods mainly include flame ball forming method, high temperature melting injection method, self-propagating low temperature combustion method, plasma method, and high temperature calcination spheroidization, etc. Chemical methods mainly include gas phase method, hydrothermal synthesis method, sol-gel method, precipitation method, microemulsion method, etc.
▼ Flame ball forming method
The process flow of the flame balling method is as follows: firstly, the high purity quartz sand is crushed, screened and purified, and then the quartz micropowder is sent into the high temperature field generated by gas-oxygen, for high temperature melting, cooling into a ball, and finally forming high purity spherical silicon micropowder.
▼ High temperature melt injection method
The high-temperature melting jet method is to melt high-purity quartz into quartz liquid at 2100-2500 ℃, after spraying and cooling, the spherical silicon powder is obtained, its surface is smooth, the spherical rate and amorphous rate can reach 100%. The high-temperature melt jet method is easy to ensure the spheroidization rate and amorphous rate, but the difficulty of this technology is the atomization system of high-temperature materials, viscous quartz molten liquid, and the problem of preventing pollution and further purification.
▼ Gas phase method
The gas phase method is based on silicon haloalkane as raw material, under the condition of high temperature hydrolysis to prepare ultrafine spherical silica powder. The silica molecules of the hydrolysis reaction agglomerate with each other to form spherical particles, and these particles collide with each other to form aggregates, which agglomerate to form spherical powder.
▼ Chemical precipitation method
The precipitation method uses water glass and acidifying agent as raw materials, adds surfactant in time, controls the reaction temperature, and adds stabilizer when the pH value of the precipitation solution is 8. The resulting precipitate is washed, dried and calcined to form silica powder. The reaction principle such as formula 5 ~ formula 6. The SiO2 generated by precipitation method has uniform particle size and low cost, and the process is easy to control, which is conducive to industrial production, but there is a certain agglomeration phenomenon.
02, Silicon micro-powder application field
Spherical silicon powder is mainly used for large-scale integrated circuit packaging, and is also used in high-tech fields such as aviation, aerospace, fine chemicals, rewritable CDs, large-area electronic substrates, special ceramics and daily cosmetics, and has broad market prospects.
▼ Copper Clad Laminate
Silicon powder as an inorganic filler used in copper clad laminate, not only can reduce costs, but also improve some properties of copper clad laminate (such as thermal expansion coefficient, bending strength, dimensional stability, etc.), is a real functional filler. With the continuous improvement of the overall technical level of the copper clad laminate industry, in a good market environment, it is required to launch high-end spherical silicon micropowder products with high purity, high liquidity, low expansion coefficient and good particle size distribution, so the application prospect of spherical silicon micropowder in the copper clad laminate industry is worth looking forward.
▼ Paints and Coatings
Spherical silica powder in coating applications can bring scratch resistance, leveling, transparency, weather resistance and other aspects of excellent performance, including decorative paint, wood paint, powder coatings, anti-corrosion coatings, floor coatings, etc.
As an energy-saving mineral raw material, spherical silica powder is used in special high-temperature ceramic materials, and it has also received ideal results in reducing the firing temperature and improving the yield of finished products. After adding spherical silicon powder to the ceramic, it is more dense, heat-resistant cold fatigue, and the strength is greatly improved. After adding spherical silica powder to special refractory materials, it has good fluidity, sintering, binding, filling pore performance, etc., so that the special refractory materials have the characteristics of dense structure, high strength, wear resistance, erosion resistance and so on.
Silicon powder, spherical, high temperature, copper plate, melting, forming, coating, special, precipitation method
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