【作者】 王海泉；

【导师】 陈秀琴；

【作者基本信息】 华侨大学 ， 材料学， 2004， 硕士

【摘要】 随着信息时代的到来，电子产品、通讯器材已成为人们日常生活的重要部分，21世界严重恶化的电磁环境会对人体健康、电子产品、电气产品及系统造成灾难性的危害。电磁波吸收材料是各国政府和科学家及社会共同关注的一个课题。 本课题旨在开发钛化物复合纤维吸波材料，该材料可望成为一种二十一世纪保护电磁环境和人体免受电磁波侵害的新型材料。 本论文以PAN基碳纤维、气相生长碳纤维(VGCF)、微米螺旋碳管为基体，采用化学气相沉积工艺制备TiC／C，TiN／C复合纤维。通过SEM、TEM、XRD和EMAX分析复合纤维的微观形态、结构和组成。探讨了反应温度、反应时间对TiC颗粒大小、镀层厚度的影响，结果表明：随着反应温度的提高和反应时间的延长，TiC层的颗粒尺寸逐渐增大，均匀程度下降；在1200℃涂层的表面形貌呈现为片状或针状结构。还对该气相沉积过程进行了动力学、热力学分析，探讨了复合纤维的形成机理。 本论文还把复合纤维添加到树脂基体中制得复合吸波板，比较了添加不同条件制备而得的TiC／C复合纤维吸收剂的复合吸波板的电磁波吸收性能，还和传统电磁波吸收剂进行了比较，并探讨了碳纤维和复合纤维的吸波机理。结果表明：以PAN基碳纤维为基体制备而得的TiC／C复合纤维的吸波板在15-35GHz频段内具有良好的电磁波吸收性能，有效带宽超过5GHz，最大吸收峰达到-15dB。随着吸收剂含量的增加，复合吸波板的吸收性能增强。TiC／C复合纤维在对频率为2G左右的电磁波就有很强的吸收性能，其吸收波能明显高于传统的吸波剂SiC、铁氧体。更多还原

【Abstract】 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.更多还原