水基石墨烯-铜复合导电浆料的制备及性能

Preparation and properties of water-based graphene-copper composite conductive paste

采用水基载体替代有机载体,以粒径为5和15μm的混合铜粉作为主导电相,添加少量石墨烯为导电增强相,按一定的质量配比制备水基石墨烯-铜复合导电浆料。用四探针测试仪、SEM等分析测试手段研究水基载体对浆料性能的影响,分析其导电机理并建立导电相连接模型。结果表明,在m(去离子水)∶m〔羧甲基纤维素钠(CMC)〕∶m〔聚乙二醇(PEG)〕∶m(消泡剂)=96.9∶1.5∶1.5∶0.1的条件下制备的水基载体性能较好;水基载体含量为30%(质量分数)时,制备的水基石墨烯-铜复合导电浆料具有优良的印刷性能,且电阻率较小,为1.65 mΩ·cm;添加石墨烯的水基复合浆料较纯铜浆料电阻率降低了97.1%,较有机载体制备的石墨烯-铜复合浆料电阻率降低了75.78%。制得的导电膜更平坦、致密,导电相间的接触更紧密,大量的石墨烯在铜粉间隙之间或横向搭接,或径向填充,与铜粉形成并联或串联的导电通道,从而形成致密的导电网络,改善复合浆料的导电性能。

Water-based graphene-copper composite conductive paste was prepared using water-based carrier instead of organic carrier, inwhich, mixed copper powder with particle size of 5 and 15 μm as mainly conductive phase and a small amount of graphene as conductive reinforcement phase. The effect of water-based carrier on the paste performance was studied by four-probe tester and scanning electron microscope(SEM). The possible conductive mechanism of water-based graphene-copper composite conductive paste was discussed and the conductive connection model was established. The results show that the prepared water-based carriers have better performance when m(deionized water)∶m 〔sodium carboxymethyl cellulose(CMC)〕∶m〔polyethylene glycol(PEG)〕∶m(defoamer) being 96.9∶1.5∶1.5∶0.1. When the content of water-based carrier is 30%(mass fraction), the prepared water-based graphenecopper composite conductive paste has excellent printing performance and a small electrical resistivity of 1.65 mΩ·cm. The resistivity of water-based composite paste with graphene is 97.1% lower than that of pure copper paste, and 75.78% lower than that of graphene-copper composite paste prepared with organic carrier.The prepared conductive film is flatter and denser, and the contact between conductive phases is more compact. A large number of graphene overlaps laterally or fills radially the gap between copper powders, forming conductive channels in parallel or in series with copper powders and forming a dense conductive network, thus improving the conductivity of the composite paste.