Understanding the Rheology of Screen-Printing Inks for the Fabrication of SOFC Thick Films

Abstract

Fabrication of SOFC components by screen-printing using an optimized ink is very significant for the production of high quality films with improved performance. Understanding the correlation between the composition and rheology of the inks may enhance the properties screen-printed films. In this study, the rheological properties of NiO/ScSZ anode inks were studied and correlated to the particle network strength, screen-printability and film properties. All the inks were fabricated using a triple roll mill. The dynamic study showed that inks having particle network strength and complex modulus in the range of 50-200 Pa and 500-4000 Pa, respectively, were determined suitable for screen-printing application. In addition, these inks showed suitable viscosity and thixotropy with acceptable tackiness for screen-printing application. This range was exhibited by inks having binder and solids loading in the range of 1-3 wt% and 25-30 vol%, respectively. Furthermore, films fabricated using these inks showed improved particle connectivity, mechanical hardness, electrical and electrochemical performance resulting from increased particle connectivity.