无铅玻璃粉对石墨烯-铜电子浆料性能的影响

Effect of lead-free glass powders on the graphene-copper electronic pastes

为提高铜浆料的导电性,以微量石墨烯为电子浆料导电增强相,与贱金属铜粉混合,加入无铅玻璃粉、有机载体制备导电性优异的复合电子浆料,并研究不同熔点玻璃粉及玻璃粉含量对复合浆料性能的影响.采用四探针测定复合浆料膜层的电阻率,采用X射线衍射和显微组织分析对样品进行表征.结果表明,熔点为430℃的玻璃粉作为黏结剂且质量分数为8%时,所制备的石墨烯-铜浆料获得较为理想的电阻率,为16.21mΩ·cm,比铜浆料降低了57.97%;分析其导电机理并建立导电模型,在导电膜层中,部分折断的石墨烯颗粒会填充到铜粉之间的空隙中,较长石墨烯片则会形成"搭桥"现象,增加导电相之间的连接,形成较紧密的微观组织和良好的导电网络,烧结后玻璃粉熔化充分润湿导电相颗粒,使导电相颗粒相互紧密接触结合,提高浆料导电性.

To increase the conductivity of the copper paste, graphene was added as conductive reinforced phase,and the copper powders were mixed with lead-free glass powders, organic carrier and graphene to prepare the electronic paste.The effect of lead-free glass powders with different melting point on the paste was studied. The desirable resistivity of the paste was measured by four-point probe, and the samples were characterized by X-ray diffraction and microstructure analysis. The results show that the desirable resistivity of the paste is 16.21 mΩ·cm,which is decreased by 57.97% compared to that of the copper pastes,when the glass powder with 8% mass fraction and 430 ℃ melting point taken as binder,and the gaps between copper powders were filled by the broken graphene. The bridges were jointed between copper powders by graphenehe flake. After sintering, the glass powders are melted to fully enwrap the conductive particles. The conductive particles are closely contacted to improve the conductivity of the paste.