Preparation Of Titanic Carbon Composited Fibers And Their Application In Electromagnetic Wave Absorption Materials

With increasing various electronic products and telecommunication equipments which are facilitating the daily life, the electromagnetic wave (EMW), which is vital to these technologies, is bringing disastrous harm to human health, as well as to the electronic equipments that are sensitive to excessive EMW. In order to reduce the negative effects of EMW, the development of EMW absorbing material has been attracting much research attention.In this work, novel EMW absorbing composite fibers of TiC (or TiN)/carbon fibers were prepared by the reaction of TiCl4 with carbon fibers such as PAN-based carbon fibers, vapor-grown carbon fibers and micron-size carbon solenoids via chemical vapor deposition (CVD) process. SEM, TEM, XRD and EMAX were applied to characterize the microstructure and compositions of the synthesized materials. The influences of CVD reaction conditions such as temperature and reaction time on the TiC particle size and the thickness of the deposited layer were investigated. Higher temperature and longer time resulted in the growth of bigger size of the TiC crystal particles, and the particle uniformity was also decreased. TiC deposited at 1200C had the crystal shape of platelets or needles instead of grains. The kinetics and thermodynamics of this CVD process and the formation mechanism of the composite fibers were discussed.The obtained TiC/C fibers were filled into resin matrix to prepared composite EMW absorption plates. These materials were proved to be excellent candidates of EMW absorbing material to protect human being and electronic equipments from destructive EMW radiation. The adsorption strength increased with the increased concentration of the TiC/C fiber in the composite absorbing plates. Especially, the TiC/C composite fiber prepared with the PAN-based carbon fibers strongly absorbed EMW in the frequencies ranging from 15GHz to 35 GHz. Strong adsorption of EMW, especially of the EMW of frequencies at about 2 GHz, was observed in the composite EMW absorption plates, in obvious contrast to the conventional EMW absorbing agents such as SiC and ferric oxide. The effective absorption band width was more than 5GHz and the biggest adsorption peak reached about -15dB.