【摘要】 为了在炭纤维表面原位生长纳米炭纤维/纳米碳管,研究它对炭/炭复合材料微观界面结构和导热性能的影响,以硝酸镍为催化剂前驱体,H2为还原气体,N2为载气,采用浸渍-还原技术在炭纤维表面制备纳米Ni催化剂颗粒。用扫描电镜观察Ni颗粒形貌和粒径,分析讨论还原温度和时间对纳米Ni颗粒的影响及纳米颗粒的形成原因。研究结果表明:随着还原温度升高,Ni颗粒逐渐变大;随着还原时间增加,催化剂前驱体涂层先分裂,再逐渐形成纳米Ni颗粒,而后又因烧结变大;H2和N2气在Ni颗粒形成过程中还起到刻蚀涂层、吸附弱化颗粒间粘结力的作用;合成纳米Ni颗粒的最佳工艺条件是:还原温度为400～450℃,还原时间为30～60min。更多还原

【Abstract】 In order to grow carbon nanofibers/carbon nanotubes on carbon fibers,and further investigate their effect on the interface microstructure and thermal conductivity of C/C composites,nano Ni catalyst particles were coated on the surfaces of carbon fibers by impregnation-reduction method using Ni(NO3)2 as catalyst precursor,H2 as reduction gas and N2 as carrier gas.The effects of reduction temperature and time on morphology and diameters of nano Ni particles were studied by scanning electron microscope(SEM),and the formation reasons of Ni particles were also discussed.The results show that the diameters of Ni particles increase with the increase of reduction temperature;Catalyst precursor coating is first broken up and then nano Ni particles are formed which then agglomerate bigger with the increase of reduction time.The formation of Ni particles is importantly due to H2 and N2 gas because they have etched catalyst coating to form small separated particle islands and adsorbed on Ni particles to prevent them associating.The optimized synthesis process of nano Ni particles is as follows: the reduction temperature is 40～450 ℃ and time is 30～60 min.更多还原