A Lead Free Graphite Conducting Paste for Screen Printing
A lead free graphite conducting pastes were prepared by using graphite powder, lead free low-melting glass and terpineol ethyl cellulose solution. By analyzing the sheet resistance, Vickers hardness as well as the adhesion strength of the sintered film prepared by the pastes formulated with different composition, the composition of the paste with preferable properties was evaluated as in mass percent: organic vehicle 60, graphite powder 15~20, and low melting glass 20~25. The films, prepared by the pastes using the lead free glass with a glass transition temperature of 476°C, were perfectly flat and compact after fired at a peak temperature within the range from 520°C to 580°C. The sheet resistance of the fired film with glass content of 25wt% was 135Ω/mm2 when the thickness of the film was 25±3μm, while the Vickers hardness and the binder force between the sintered film and the substrate were favorable. In addition, the rheological behaviors of the typical paste were characterized by using an ARES (RFS-III) rheometer. It is found that a weak flocculated network structure is formed in the paste for the high solid filler.
Xiaoming Sang, Pengcheng Wang, Liqun Ai, Yungang Li and Jinglong Bu
S. Y. Luo et al., "A Lead Free Graphite Conducting Paste for Screen Printing", Advanced Materials Research, Vols. 284-286, pp. 2230-2233, 2011