Effect of particle packing on extrusion behavior of pastes

Two powders with different average particle sizes and size distributions were blended in various proportions. The influence of powder mixing on extrusion behavior of pastes containing a water-based binder has been examined. The bimodal mixed stainless steel powder exhibits a low extrusion pressure, small amount of binder and high green density when the mixing fractions of large and small particles are approximately equal. With regard to the mixing of zirconia and stainless steel powders, a similar result has been found, but the mixing fraction of powder corresponding to the optimal packing is shifted to stainless steel-side. In order to improve the extrudability of pastes, it is effective to mix two powders with a large difference in particle size. (C) 2000 Kluwer Academic Publishers.