Preparation Of Biological Microporous SiC

Silicon carbide material has specific mechanical properties, chemical properties and electrical properties. It is a substance of oxidation resistance, corrosion resistance and highly chemically inert. It has a higher thermal stability and conductivity and a smaller thermal expansion coefficient. And it exhibited semiconductor properties at high temperatures. Therefore, it can be made to abrasives, building materials, heat exchangers, electronics, sensors materials and so on, in the field of national defense, aviation, metallurgy, chemical industry and others has a wide range of applications. Porous silicon carbide has widened the application in the field of catalysis, energy storage, biomedical and environmental protection.Diatomaceous earth is a natural mineral, found in nature. Its main component is silicon dioxide. It also contains iron oxide, aluminum oxide and other impurities. Thus its purity is not high. In the past, it was used as the filter and decolorizing material merely but its unique biological porous structure was not utilized fully. It belongs to the early development of products, economic efficiency is relatively low. Therefore, the development of its new value is very meaningful. Biological Porous silicon carbide prepared using diatomaceous earth as a raw material has the microstructure of diatomite. And biological porous SiC has the excellent performance of SiC also has good biocompatible sexual, physical and chemical stability, nontoxic side effects. It was developed into a higher value of biomaterials, such as artificial bone, becoming one of the focus in the future biomedical research and biomedical fields. Therefore, biological microporous silicon carbide will has good economic and practical value.In this paper, diatomite with biological pores structure was used as raw material. Fine diatomite with high content of SiO2 and large specific surface area was prepared by acid leaching and calcination treatment. Then mixed fine diatomite with carbon powder as raw material, via carbon thermal reduction at 1200-1500 ℃ calcinations for different times to prepare high-purity β-SiC products. The results show that the yield increased, the specific surface area decreased as the increase of calcination temperature and time. The best preparation conditions of bio-microporous SiC is mixing diatomite evenly with carbon powder as the amount of substance ratio 1:3, then compressed them into billet, afterward calcined the billet at 1400 ℃ for 4 h. It is confirmed that the product is β-SiC by FT-IR and XRD. The SEM showed that the prepared SiC holds micropores microstructure of diatomite. Specific surface area of the product was test by Physical adsorption analyzer and it is 97.56 m2/g. The average particle size is 40 μm, the apparent density is 1.4336 g/cm3, porosity is 68.41%, hardness is 7.8 GPa, acid and alkali resistance and other chemical and physical properties. Bio-microporous silicon carbide prepared in this manner not only has high purity and high porosity but also is low energy consumption and better economic efficiency.