Application status of crystalline silicon powder

 Crystalline silicon micro powder (SiO2) is a widely used inorganic nonmetallic material, which has excellent dielectric properties, low thermal expansion coefficient, low thermal conductivity and corrosion resistance. At the same time, high quality silicon micro powder has become one of the important and key raw materials in high-tech field because of its excellent physical properties, high chemical stability and unique optical properties.

Crystalline silicon micro powder is a kind of micro powder made of natural quartz (SiO2) or fused quartz (non crystalline SiO2 after high temperature melting and cooling) through crushing, ball milling (or vibration, air flow grinding), flotation, pickling purification, high purity water treatment and other processes.

(1) Application in electronic and electrical industry

At present, modern microelectronics technology is developing towards high integration, high density and miniaturization with amazing speed. The rapid development of advanced packaging technology of spherical silicon powder has put forward higher and higher requirements for packaging materials. 70% - 90% of the epoxy plastic materials used in IC packaging are silicon powder. When the integration degree reaches 1m-4m, it is required to add some spherical silicon powder, while when the integration degree reaches 8m-16m, spherical silicon powder must be used. It is used in electronic industry, including electronic grade crystalline silicon powder, electronic grade crystalline active silicon powder (JGH), electronic melting silicon powder and electronic grade melting type active silicon powder. The product specification is the number of product net, which is divided into 300, 400, 600, 1000 mesh.

(2) Application of wear-resistant rubber products

The rubber products include rubber plate, tube, belt and roller. It requires that the rubber blend has good permeability and strong adhesion. The test results show that the rubber filled with silica powder fully reflects the unique properties of the rubber material thin, good permeability, good dispersion and strong adhesion, which is conducive to the friction of the rubber on canvas and the adhesion strength between the film and canvas, and the preparation of the rubber The mechanical properties of the products such as breaking strength and permanent deformation have been improved obviously, especially the wear resistance of rubber products is enhanced.

(3) Application of silicone rubber products

High quality ultra micro SiO2 has high whiteness, high hardness, high temperature resistance and flame retardant. Its molecular structure is similar to that of silicone rubber. It can be used for the modification of reinforcing agent and resin based composite of silicone rubber, as well as additives for new plastics, plexiglass, coatings, paper and other products, and also for large-scale electronic plastic sealing. It can be used in infrared shielding, UV radiation resistance, high dielectric insulation and electrostatic shielding in functional materials, and also has important applications in bionic materials and other fields.

(4) Other applications

In refractory industry, crystalline silicon micro powder is used as additive to prepare high performance refractories. In chemical industry, it can be used as inert filler in various compounds instead of silicate materials such as talc and kaolin. In the construction industry, cement admixture can be used to reduce the water cement ratio, improve and ease of use; for reinforced concrete, the compactness of concrete can be greatly improved and the leakage resistance can be enhanced, such as for hydropower dams and large and small water pools.

At present, almost all silicon powder production enterprises in China use conventional processing equipment of non mineral industry, including crushing, grading and drying. In the process, there is no systematic control means, and some enterprises take simple online monitoring and off-line control measures, but still can not solve the fundamental problems. As for the cleanliness of the production environment, it is more worrying. Therefore, the purity, granularity and stability of the products are poor, which can not be counterbalanced with the imported products abroad. Driven by the rapid development of domestic microelectronics industry, the amount of spherical silicon powder is increasing day by day. Because foreign manufacturers have strictly blocked and monopolized the introduction of production technology and special equipment of spherical silicon micro powder in China, since the "Tenth Five Year Plan", some domestic research units, such as Tsinghua University, Wuhan University and Nanjing University, have been tackling the key issues, but they are still in practice at present In the laboratory stage, industrialization has not been realized.