Control of Porous Materials Structure Based on the Design of Surface Interaction between Fine Particles by Surface Modification

点击翻译按钮获取中文摘要

In order to prepare high performance and high reliability ceramics, it is necessary to avoid the irregular aggregate structure in their original ceramic slurries before green compact formation. In order to control the aggregation structure of ceramic powders in slurry, polymer dispersants are generally added. However, since the mechanism of polymer dispersants adsorbed on powder has not been clarified, the amount and molecular structure of polymer dispersant (hydrophobic to hydrophilic ratio, e.g.), pH, counter-ion concentration to obtain the minimum suspension viscosity have been often decided by an empirical approach.In this work the systems of the powder of silica, alumina, silicon nitride with and without metal oxide additives and silicon carbide have been chosen to clarify the action mechanism of polymer dispersant in dense suspension and to correlate the macroscopic suspension viscosity and microscopic surface interaction between particles measured by an atomic force microscopy (AFM).The following topics have been focused :1) Influence of particle diameter on surface silanol structure, hydration force, and aggregation behavior of alkoxide-derived silica particles2) Effect of anionic polymer dispersant structure and content on dense alumina suspension viscosity analyzing with the electrosteric interaction of polymer dispersant by AFM and colloid probe AFM under different counter-ion densities3) Analysis of anionic polymer dispersant behavior in dense silicon nitride suspensions with and without oxide additives by using AFM and colloid probe AFM4) Effect of anionic polymer dispersant structure and aggregation behavior on dense silicon carbide suspension characteristics and slip-casted green body structure5) Control of microstructure and surface behavior of silica gel prepared from metal oxide