固化过程及银粉形貌对导电胶电阻率的影响

Effect of curing process and morphology of silver powder on resistivity of ECA

采用2种不同形貌的银粉、3种不同固化收缩率的导电胶基体配制6种导电胶,研究等温固化过程中导电胶基体的固化收缩率以及银粉形貌对导电胶电阻率的影响,探讨导电胶的导电机理。结果表明,银粉形貌对导电胶的电阻率影响较小;基体固化收缩率越大,使得银粉颗粒之间的接触面积增大,发生隧道效应的几率也增大,所以导电胶的电阻率越小,基体的固化收缩对导电胶导电性能的形成贡献较大,在导电胶由不导电到导电的转变过程中起着决定性的作用。导电胶未固化前是不导电的,导电性的建立发生在导电胶基体的凝胶化阶段,且在这一阶段中导电胶的电阻率随时间延长急剧下降,之后趋于稳定。

Based on two kinds of silver powder with different morphology and three matrixes with different curing shrinkage, six electrical conductive adhesives （ECA） were prepared. The effects of the curing shrinkage of matrix and the morphology of silver powder on the resistivity of the ECA were studied. The conductive mechanism of ECA has also been explored. The results show that the morphology of silver powder has less influence on the resistivity, while the curing shrinkage of the matrixes contributes more to the conductivity developments and plays a crucial role in the process of conductivity achievement. The higher shrinkage of the matrix curing, the lower the resistivity. The ECA are nearly insulated before cured. Its conductivity establishment is completed during the gelatinization stage, the conductivity dropped sharply first and then changed slightly in the process of the conductivity establishment.