The Physical And Chemical Indexes Of Silicon Powder For Electronic And Electrical Industry

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Silica fume, also called micro-silica fume, scientific name "silica fume", is made by special trapping device to collect and process the smoke and dust escaping from exhaust gas during the process of smelting industrial silicon and ferrosilicon at high temperature in industrial electric furnace. In the escaping smoke and dust, the content of SiO2 accounts for about 90% of the total smoke and dust. The particle size is very small, and the average particle size is almost nanometer level, so it is called silica fume.
 
Intensity influence
 
Although pure cement can be used to make HPC with a compressive strength of up to 100 MPa, it is much easier when using silica fume. For the preparation of concrete with a strength exceeding 100 MPa, the use of silica fume is almost indispensable. Silica fume is used as a filling material and a pozzolan material in the concrete. After the use of silicon powder, the pore size in the hydration slurry is greatly reduced, and the pore size distribution is improved, so that the strength is improved and the permeability is reduced. For example, the research results show (CEB2FIP1988) that in order to obtain a concrete strength of 70 MPa, the application of pure cement requires a water-to-binder ratio of 0.35, and when 8% silica fume is added, the water-to-binder ratio can be 0.50. Because the silica fume particles are very fine, they can undergo a pozzolanic reaction within a few hours early. According to Carette and Malhotra 1992), the contribution of silica fume to the strength of concrete is mainly before 28 days. Therefore, in terms of long-term strength growth, it is generally believed that silica fume concrete is inferior to pure cement concrete or fly ash concrete. Almad (1994) cited the experimental results of silica fume on the strength development of NSC, which showed that the increase in the amount of silica fume reduced the early relative strength development. Sandvik 1992 also found this phenomenon in 65 MPa concrete.
 
The physical and chemical indexes of silicon powder for electronic and electrical industry
 
Product classification and code name of micro-silicon powder for electronic and electrical industry (SJ/T10675-2002): For the electrical industry, there are ordinary silicon micro-powder (PG), ordinary active silicon micro-powder (PGH), electrical-grade silicon micro-powder (DG), and electrical-grade active Silicon powder (DGH). Used in the electronics industry, there are electronic grade crystalline silicon powder (JG), electronic grade crystalline active silicon powder (JGH), electronic grade fused silica powder (RG), and electronic grade fused active silicon powder (RGH). Product specifications are the number of product meshes, divided into 300, 400, 600, and 1000 meshes.

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