The fine defective structure of silicon carbide powders obtained from silicic acid-saccharose, aerosil-saccharose, aerosil-carbon black, and hydrated cellulose-silicic acid gel systems was investigated. The relation between IR absorption characteristics and the microstructure of SiC particles obtained from different starting materials was established. The numerical relationship between the lattice parameter a and the frequency ?TO is presented.
A new method for producing silicon carbide platelets with low cost and high yield was
introduced. The silicon carbide platelets were synthesized by powder-heating techniques with carbon
black and SiO2 powder as raw materials and CoCl2 as catalyst. The starting mixtures were heated at a
temperature in the range of 1800-2000°C for the duration of about 2-4h to produce substantially
completely unagglomerated silicon carbide platelets with a thickness of 5-20μm and the average diameter
of 50-200μm. Compared to the conventional heating, the powder-heating technique is advantageous of
less investment on equipment, easy to manufacture and convenient to operate. Furthermore, it is very
suitable for realizing the scaled production because of the lower synthesizing temperature, shorter
reaction time and greater output.
To solve more and more serious electromagnetic radiations, electromagnetic wave absorption cement were prepared by introducing carbon black and glass fiber as composited absorbing reagent, wich can be useful in building anechoic chamber and other electromagnetic radiation protection to buildings. The results showed that the absorption properties were improved compared with single absorbing agent such as carbon or glass fiber. the lowest reflection loss of-11.3dB was obtained at 18 GHz of 5wt.% carbon black and 9wt.% glass fiber filled cement with thickness of 20mm. The increase of thickness separately can not improve the absorption properties.
Double Layer Material Designed to Reduce Electromagnetic Radiation with Carbon Black, Silicon Carbide and Manganese Zinc Ferrite