| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 103 === In the last decades, much research had been dedicated to improving the performance of high-solid-content silver pastes. However, reducing the silver content of the pastes while maintaining low resistance of silver thick films is a long-term goal in current industries. For this purpose, we systematically investigated the rheological behavior of low-solid-content silver pastes (47wt%) and the performance of their screen-printed thick films. Both rotational and oscillatory measurements were carried out to scrutinize the viscoelastic behavior of silver pastes under the influences of polymer binder, surfactant, and silver powder. Scanning electron microscope (SEM), tensile strength and sheet resistance were used to analyze the performance of silver thick films. From this study, it was found that silver pastes which contained polymer binder and a specific surfactant exhibited time-evolving behavior, which can be fine-tuned through a proper combination of binder, surfactant, and silver powder. This phenomenon implied that the interaction of silver powder and polymer binder is promoted, and showed the improvement of the dispersion state of silver powder as later confirmed by the SEM micrographs. In addition, the results from this study suggested that the rheological properties of pastes are highly associated with the dispersion state of silver powder, printability of pastes, and performance of silver films. Accordingly, the present findings provide more specific information for assessment of paste quality.
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