李仲
,
英哲
,
刘敏
,
成会明
新型炭材料
doi:10.3969/j.issn.1007-8827.2005.02.003
采用传统的熔融纺丝技术大量制备了定向性良好的纳米碳管/聚丙烯复合纤维.扫描电镜观察证实了纳米碳管在纤维里的定向性以及分散性都得到了较大的改善.通过拉伸实验测试了纳米碳管/聚丙烯复合纤维的力学性能,采用Weibull统计分析发现纳米碳管的添加显著提高了复合纤维的拉伸强度,当添加纳米碳管的质量分数达到3 %时,纤维强度最高,达到61MPa,超过聚丙烯纤维强度120%.复合纤维拉伸断口的形貌特征也证实了纳米碳管添加对复合纤维拉伸性能影响存在临界现象.
关键词:
多壁纳米碳管
,
聚丙烯
,
复合纤维
,
熔融纺丝
,
拉伸强度
Caiyin YOU
金属学报(英文版)
Magnetic properties, phase evolution and microstructures of Pr9.44Fe90.56-xBx (x=7.16 and 4.76) nanocomposite magnets have been investigated. Both as-spun ribbons exhibit two-step demagnetization curves, indicating the feature of partial crystallization. By using differential scanning calorimeter (DSC) measurements, remained amorphous phase of ribbon with x=7.16 shows a higher crystallization temperature. At optimum annealing temperature of 650 ℃ for 10 min, better magnetic properties, Mr=1.01 T, jHc=796 kA/m and (BH)max=136 kJ/m3 were obtained in the sample with x=4.76. Transmission electron microscopy (TEM) observation confirms that the sample with x=4.76 possesses much finer grain size, which causing a better exchange coupling between soft and hard magnetic grains.
关键词:
Nanocomposite magnet
,
melt spinning
,
exchange coupling
,
microstructure
