Leveling and thixotropic characteristics of concentrated zirconia inks for screen-printing
- 607 Downloads
Screen-printing is a cost-effective method for the mass manufacture of zirconia-based solid oxide fuel cells (SOFCs) and oxygen separation membranes. The present work outlines an investigation into the leveling, thixotropic, and screen-printing characteristics of concentrated zirconia inks by a variety of rheological and imaging methods. A combination of viscosity, shear rate jump experiments, creep and recovery analysis, and yield stress measurements were used to assess ink thixotropy. Oscillatory rheometry and scanning electron microscopy/optical microscopy revealed a consistent effect of ethyl cellulose (binder) content upon the thixotropic and leveling characteristics of zirconia inks. While the yield stress (τ 0), extent of recovery R(%), and rate of recovery (K) increase with increasing binder content, so did the surface roughness and thickness of the screen-printed films. Increasing the binder content not only increases the network strength of the thick films but also leads to increased leveling time. As a result, rheological modifiers are proposed to be necessary to improve the leveling characteristics of zirconia inks without losing the green strength of the thick films.
KeywordsInks Thixotropy Yield stress Leveling Coatings
The author gratefully acknowledges Lene Knudsen for the preparation of the ink samples.
- Camina N, Roffey CG (1971) Statistical interpretation of viscoelasticity. Rheol Acta 10:606–609Google Scholar
- Coussot P, Nguyen QD, Huynh HT, Bonn D (2002a) Avalanche behavior in yield stress fluids. Phys Rev Lett 88:175501.1–175501.4Google Scholar
- Fraioli AV (1974) Yield values in thick-film rheology. Solid State Technol 17:48–50Google Scholar
- Mezger TG (2006) The rheology handbook. Vincentz Network, Hannover, pp 1–299Google Scholar
- Pierrehu RC (1974) Experiments in measurement of leveling of latex paints. J Paint Technol 46:31–36Google Scholar
- Quach A, Hansen CM (1974) Evaluation of leveling characteristics of some latex paints. J Paint Technol 46:40–46Google Scholar
- Voisard C (2004) Manufacturing solid oxide fuel cells for the sulzer hexis stationary system. Int J Appl Ceram Technol 1:31–39Google Scholar
- Zhang YH, Huang XQ, Lu Z, Liu ZG, Ge XD, Xu JH, Xin XS, Sha XQ, Su WH (2006a) A novel method for fabrication of Y2O3-stabilized ZrO2 electrolyte films. J Am Ceram Soc 89:2304–2307Google Scholar