中文摘要：

采用磁场辅助固化工艺，制备了纳米碳包镍／环氧树脂复合材料，用SEM观察了复合材料的微观组织，测量了复合材料的直流电学特性，考察了磁场强度、纳米粒子含量、温度对电性能的影响。在无磁场情况下固化时，纳米粒子在环氧树脂中均匀分布；而施加磁场后，纳米粒子在基体中以纤维状线性排列；施加的磁场越大，纤维组织发育得越粗壮，获得的复合材料的电阻率越小。复合材料的I-U曲线呈现非线性特征，表明电导机制依赖于导电粒子之间的隧道传递，电阻率随温度上升而下降，显示奇怪的负温度系数（NTC）效应，且可由填料含量、磁场强度调节。为解释NTC起源，提出一个修正的量子隧道模型。根据该模型，复合材料的NTC效应归因于占统治地位的电子热活化隧道传递；另一方面，环氧树脂的低膨胀率促成了这一效果。

英文摘要：

Epoxy resin （ER） composites filled with aligned carbon coated nickel （Ni - C） nanoparticle were prepared by use of magnetic field assisted curing process, and the electrical properties were tested. The higher the content of nanoparticles, the greater the magnitude of the magnetic field applied, the lower the resistivity of the composites obtained. I- U characteristic of the composites is tested nonlinear, indicating that the electrical conduction depends on the tunneling transport of electron cross the adjacent Ni C nanoparticles. The resistivity of the composites exhibits negative temperature coefficient （NTC） effect above the room temperature, and can be adjusted by varying the filler content and the magnitude of magnetic field. A modified quantum tunneling model was developed to understand the origin of NTC effect in the composites, which shows that the NTC effect is attributed to the dominant thermal activation tunneling of electron, and to the low thermal expansivity of the epoxy resin matrix.