Object of this work is to analyse experimentally the rheological behavior of the consolidated suspension layer. The experiment has started when the consolidated particle bed expanded visco-elastically after loading on the bed was reduced. To confirm the visco-elastic expansion of the suspension, and uniaxial compression test (UCT) was applied for a highly filled suspension (HFS) at a constant concentration of the same material as the consolidation experiment. Stress hardening was observed after loading on the UCT. A three-element model (Voigt model plus an elastic element) was found to be simple and sufficient to represent the response of the creep test after stress hardening was achieved. The expansion experiment of the consolidated HFS bed showed that real expansion appeared after loading on the bed was reduced to some limited one, F_B, from the original load, F_A. It was confirmed from the experiment that the load difference (F_A-F_B) corresponded to the friction between the cylinder wall and HFS. The visco-elastic expansion of the HFS bed on the load region less than F_B showed the strain approached the predicted strain curve from the UCT experiment.

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In order to analyse the consolidation process, it was assumed that the highly filled suspension (HFS) was to be an elastic body. Using the final strain observed in an expansion test of the consolidated bed and the elasticity constant obtained in an uniaxial compression test in the previous work, elastic stress of the HFS was expressed as a function of the void ratio. Permeability experiment of the HFS bed was also engaged to confirm the Kozeny-Carman equation and to obtain the meterial constant in the equation. A stress equilibrium equation was derived during consolidation involving elastic stress of the HFS, static pressure for permeation and wall friction on the cylinder wall. Combining this with the continuity equation, a new consolidation equation with modified initial and boundary conditions was proposed. The solutions of the new equation could predict well the consolidation results of H-Bentonite and Kaolin suspensiouns until the middle of the consolidation process. The deviation of the approximate solution from experiments gave useful information to understand the so called “secondary consoliation process.”

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Composite fine particles were prepared by using polymethyl methacrylate latex (diameter c. 6μm) as the core and silica particles (0.51μm) as the shell by the addition of a cationic surfactant (cethyltrimethylammonium bromide).
As the results, the zeta potential of both particles could be adjusted by controlling such factors as pH and the concentration of the surfactant. The coverage of the core surface with silica particles went up to over 0.82 under the optimum preparation condition. The theoretical maximum coverage under that circumstance was 0.91. The coverage and the logarithm of the stability ratio estimated on the basis of the DLVO theory bore a linear relationship to each other.

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A new method for preparing surface-modified ceramic particles was proposed. Applying a silent mode electrical discharge as the means of activation in the CVD reactions, it is possible to prepare ceramic particles which have organic groups on the surface.
The surface-modified ultrafine SiO₂ particles were prepared from various organosilicon compounds. The particles were characterized by thermal analyses and infrared spectrum measurements. The organic groups which were contained in the material existed on the particle surface and hence showed a hydrophobic character. Ultrafine hydrophobic SiO₂ particles could be synthesized directly from the reactant gases without secondary surface-treatment. The surface methyl groups were very heat-stable in comparison with other organic groups.

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