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VAPOR PHASE PREPARATION OF ELECTRIC CONDUCTIVE AND MICRO-COILED METAL NITRIDE FIBERS AND THEIR ELECTROMAGNETIC ABSORPTION PROPERTIES

导电微卷金属氮化物纤维的气相制备及其电磁吸收性能

基本信息

批准号：
09650731
负责人：
MOTOJIMA Seiji
金额：
$ 2.05万
依托单位：
GIFU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650731/
关键词：
Carbon fibers Vapor grown carbon fibers (VGCF)Carbon coils Micro-coils Micro-tubes Metal nitrides TiN NbN マイクロコイル

项目摘要

Micro-coils or micro-tubes of various metal nitrides were prepared by the vapor phase nitriding of metal carbide coils (indirect process or two step process) and metalizing/nitriding of carbon coils (one step process or direct process), and the preparation conditions, mechanism, microstructure, properties were examined. The obtained results can be summarized as follows.(A) Indirect process or two step process :(1) The carbon micro-coils was vapor phase titianized at 800-1200ﾟC under TiCl4 + H2 atmosphere to form TiC micro-coils. Using regular carbon coils, the obtained TIC micro-coils have micro-tube like morphology.(2) The TiC micro-coils was nitrided at 800-1200ﾟC in N2 atmosphere. The TiC micro-coils was partly nitrided at 800ﾟC for 6-hr reaction times to form TiN/TiC micro-coils/tubes.(3) TiC micro-coils was fully nitrided to the core at 1000ﾟC for 6-hr reaction time to form TiN micro-coils/micro-tubes.(B) Direct process :(1) The carbon coils was treated with MCI (M=Ti, Nb, Ta, Si) … More +N2+H2 atmosphere in the temperature range of 800-1200ﾟC.(2) The carbon coils changed to metal nitride with full preservation of the coiling pattern, without the formation of intermediate layers of metal carbides.(3) Using very regular-coiled carbon fibers, the coiling pattern gradually disappeared with increasing reaction temperature and reaction times, and then fully disappeared to form apparent straight fibers of 3-10 mum diameter.(4) The straight fibers have a continuous pore of submicrom diameter through the fiber axis. That is, this straight fibers obtained by the metarizing/nitriding of the regular carbon coils is a micro-tube of metal nitride.(5) The carbon coils was fully titanized/nitride to the core at 1000ﾟC for 6 hrs, while partly titanized/nitrides from the surface at 800ﾟC for 6 hrs.(6) The large specific surface area of carbon coils ; about 100m^2/g, was decreased to 10-20m^2/g by the metalizing/nitriding, depending on the reaction temperature and reaction time.(7) The metal nitride micro-coils/micro-tubes have bulk electrical resistivities of 0.1-0.01 "0"cm depending on the bulk density and conversion ratio of the carbon coils to the metal nitride.(8) The electromagnetic wave absorption of the metal nitride micro-coils/micro-tubes was about 90% in 800-900 MHz region for 20wt% in an epoxy resin. Less

采用金属碳化物卷气相氮化（间接法或两步法）和碳卷金属化/氮化（一步法或直接法）制备了各种金属氮化物的微线圈或微管，并对其制备条件、机理、组织和性能进行了研究。所获得的结果可以总结如下。(A)间接法或两步法：（1）在800-1200 ℃、TiCl_4 + H_2气氛下对碳微线圈进行气相钛化，形成TiC微线圈。使用规则的碳线圈，所获得的TIC微线圈具有微管状的形态。(2)TiC微线圈在800-1200 ℃下在N2气氛中氮化。TiC微线圈在800 ℃下部分氮化6小时反应时间以形成TiN/TiC微线圈/管。(3)TiC微线圈在1000 ℃下完全氮化至芯部，反应时间为6小时，以形成TiN微线圈/微管。(B)直接法：（1）用MCI（M=Ti，Nb，Ta，Si）对碳卷进行表面处理; ...更多信息 +N2+H2气氛中，温度范围为800-1200 ℃。(2)碳线圈变成金属氮化物，完全保留了线圈图案，而没有形成金属碳化物的中间层。(3)使用非常规则的卷曲碳纤维，随着反应温度和反应时间的增加，卷曲图案逐渐消失，然后完全消失，形成直径为3-10 μ m的明显的直纤维。(4)直纤维具有贯穿纤维轴的亚微米直径的连续孔。也就是说，通过常规碳线圈的金属化/氮化获得的这种直纤维是金属氮化物的微管。(5)碳线圈在1000 ℃下完全钛化/氮化至芯部6小时，而在800 ℃下从表面部分钛化/氮化6小时。(6)碳卷的比表面积约为100 m^2/g，经金属化/氮化处理后可降至10- 20 m^2/g，其变化取决于反应温度和反应时间。(7)金属氮化物微线圈/微管具有0.1-0.01 - 0-cm的体积电导率，这取决于碳线圈与金属氮化物的体积密度和转化率。(8)在800-900 MHz范围内，当在环氧树脂中的质量分数为20%时，金属氮化物微线圈/微管的电磁波吸收率约为90%。少