张墅野, 许孙武, 曹洋, 林铁松, 何鹏. 新型导电胶中铜粉表面化学镀纳米银颗粒的导电机理研究[J]. 焊接, 2019, (2): 1-5. DOI: 10.12073/j.hj.20181107006
引用本文: 张墅野, 许孙武, 曹洋, 林铁松, 何鹏. 新型导电胶中铜粉表面化学镀纳米银颗粒的导电机理研究[J]. 焊接, 2019, (2): 1-5. DOI: 10.12073/j.hj.20181107006
ZHANG Shuye, XU Sunwu, CAO Yang, LIN Tiesong, HE Peng. Study on conductive mechanism of silver coated copper powders for conductive adhesives[J]. WELDING & JOINING, 2019, (2): 1-5. DOI: 10.12073/j.hj.20181107006
Citation: ZHANG Shuye, XU Sunwu, CAO Yang, LIN Tiesong, HE Peng. Study on conductive mechanism of silver coated copper powders for conductive adhesives[J]. WELDING & JOINING, 2019, (2): 1-5. DOI: 10.12073/j.hj.20181107006

新型导电胶中铜粉表面化学镀纳米银颗粒的导电机理研究

Study on conductive mechanism of silver coated copper powders for conductive adhesives

  • 摘要: 通过讨论集中电阻及邃穿电阻的影响因素来分析覆纳米银铜粉导电胶的导电机理。系统地从理论计算和试验验证两方面考察了导电胶的固化工艺对电性能的影响;考察了所制备的导电胶对铜板的电性能;并对纳米填料对导电胶导电机理影响进行了分析。结果表明随着填料体积分数的增加,填料之间距离越小,相互接触的概率越大。填料之间接触点越多集中电阻越小,当填料相互之间的距离足够小时隧穿电子或场致发射电子才能通过树脂基体。因此填料体积分数只有达到渗流阈值以后,才有优良的导电性;导电填料的形貌主要影响集中电阻的大小。树枝状的覆纳米银铜粉,由于其枝干长,枝杈多,相互搭接的概率大大加大,从而降低了集中电阻;纳米银颗粒主要影响隧穿电阻的大小。纳米银颗粒表面能高,在170~200℃即出现熔化现象,为电子跨过势垒,形成隧穿电子提供足够的能量。最后场致发射现象也影响着隧穿电阻的大小。这是由于在导电胶固化连接铜板之后,铜板两端施加电压较高时,在搭接面之间的导电胶中产生较强的均匀电场,产生场致发射现象,增强了导电胶的电性能。

     

    Abstract: The conductive mechanism of the nano-silver-copper powder conductive adhesive was analyzed by discussing the influencing factors of the concentrated resistance and the breakdown resistance. The effects of curing process of conductive adhesive on electrical properties were systematically investigated from theoretical calculations and experimental verification. The electrical properties of the prepared conductive paste on copper plates were investigated. The influence of nano fillers on the conductive mechanism of conductive adhesives was analyzed. The results show that as the volume fraction of the filler increases,the smaller the distance between the fillers,the greater the probability of contact with each other. The more contact points between the fillers,the smaller the concentration resistance,and the tunneling electrons or field emission electrons can pass through the resin matrix when the distance between the fillers is sufficiently small. Therefore,the filler volume fraction has excellent conductivity only after reaching the percolation threshold. The morphology of the conductive filler mainly affects the size of the concentrated resistance. The dendritic nano-silver-copper powder has a large branch length and many branches,and the probability of overlapping each other is greatly increased,thereby reducing the concentrated resistance. The nano silver particles mainly affect the size of the tunneling resistance. The surface energy of the nano-silver particles is high,and melting occurs at 170-200 ℃,which provides sufficient energy for electrons to cross the barrier and form tunneling electrons. Finally the field emission phenomenon also affects the tunneling resistance. This is because after the conductive paste is solidified and the copper plate is applied,when a voltage is applied across the copper plate,a strong uniform electric field is generated in the conductive paste between the lap joints,and a field emission phenomenon is generated,thereby enhancing the electrical properties of the conductive paste.

     

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