| 纳米碳包镍/环氧树脂复合材料的NTC效应及其调节 |
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| 引用本文： | 张邦文,李保卫.纳米碳包镍/环氧树脂复合材料的NTC效应及其调节[J].复合材料学报,2008,25(5):39-44. |
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| 作者姓名： | 张邦文 李保卫 |
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| 作者单位： | 内蒙古科技大学材料与冶金学院, 白云鄂博矿稀土及铌资源高效利用省部共建教育部重点实验室, 包头 014010 |
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| 基金项目： | 国家自然科学基金项目（No 50704021）和内蒙古自治区高等学校科学研究项目（No NJ06074） |
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| 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。
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| 关 键 词： | 纳米碳包镍 环氧树脂 复合材料 NTC 隧道传递模型 磁场 |
| 收稿时间： | 2007-10-15 |
| 修稿时间： | 2008-03-31 |
NTC effect and the adjustment in nano Ni-C/ER composites |
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| ZHANG Bangwen,LI Baowei.NTC effect and the adjustment in nano Ni-C/ER composites[J].Acta Materiae Compositae Sinica,2008,25(5):39-44. |
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| Authors: | ZHANG Bangwen LI Baowei |
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| Affiliation: | Key Laboratory of High Efficiency Utilization of Rare Earth and Niobium for Bayan Obo Resource, Ministry of Education, College of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, China |
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| Abstract: | 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. |
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| Keywords: | NTC |
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