导电胶导电/导热性能影响因素研究

Study of the influence factors on the electrical and thermal conductivity of conductive adhesive

选用双氰胺固化环氧树脂体系制备导电胶，分别研究了银粉含量和尺寸、低熔点合金以及短链二元酸的添加对导电胶导电／导热性能的影响。结果表明，所制导电胶的导电及导热性能均随银粉含量的增加或尺寸（3～9LLm）的增大而增强。低熔点合金可在银粉间形成冶金键合，降低银粉间的接触电阻与热阻，从而有效提高导电胶的导电及导热性能。少量己二酸的添加可有效去除银粉表面的绝缘油酸，提高导电胶的导电性能，同时其会与双氰胺反应起到偶联作用，降低银粉与树脂的接触热阻，最终有效提高导电胶的导热性能。

Dicyandiamide-cured epoxy resin was selected as the system of electrically conductive adhesives （ECAs）. The influences of the silver powder content and size, low-melting alloy and adipic acid doping on ECAs＇ electrical and thermal conductivity were studied. The result reveals that both the electrical and thermal conductivity of the ECAs increase with the content or size （from 3 ~tm to 9 ~tm） of the silver powder increasing. The low-melting alloy can sinter with the sliver powders, and then decrease the contact resistance and interface thermal resistance between the sliver powders so that both the ECAs＇ electrical and thermal conductivity are improved significantly with the addition of a small amount of low-melting alloy. Doping a little amount of adipic acid could remove the insulating oleic acid on the surface of the silver flakes, which results in improvement on the electrical conductivity of the ECAs. Moreover, the adipic acid could react with dicyandiamide simultaneously, playing the role of coupling agent in this system, which would eventually improve the thermal conductivity of the ECAs.