Rheological behavior of alumina water-base suspension and properties of green sheets was investigated. In the case of 0.6μm alumina, the suspension showed shear thinning flow behavior at 0.7Pa yield stress, suggesting that the alumina particles are partially flocculated. On the other hand the suspension of 1.7μm alumina showed a behavior close to Newtonian flow, suggesting that the alumina particles are well dispersed. Through the adsorption isotherm measurement of binder on alumina particles, each binder molecule is estimated to occupy 19.6nm² and adsorbs on the alumina surface with stretched conformation like ‘tail’ or ‘loop’ in both cases. The critical solid content of 0.6μm alumina suspension measured by additional vaporization method was smaller than that of 1.7μm alumina suspension. This is the same tendency as the result that the packing density of 0.6μm alumina green sheet was smaller than that of 1.7μm alumina green sheet. The non-adsorbed binder in suspension is found to accumulate between alumina particles and affect the tensile properties of green sheets after drying.

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Although crystallization process is optimized mainly with respect to the physicochemical properties, the mechanical properties such as the strength of crystal particles are the important factors in the industrial process because the crystallization usually follows the filtration process and the filtration time occupies relatively a long time in the whole processing time. In this study, the crystallization process of a sulfate which forms spherical agglomerate of primary crystal particles has been studied with particular attention to the effect of the operating conditions of crystallization on the filtation characteristics of crystal agglomerates.
The filtration characteristics were evaluated by the specific resistance calculated from Darcy's equation through the filtration experiments carried out under constant pressure drop. The compression ratio is also measured with a tapping method. It was found that the specific resistance has almost no correlation with the compression ratio, suggesting that the compression ratio is an inadequate parameter for the evaluation of the filtration characteristics. The specific resistance of agglomerated crystal is higher at a lower crystallization temperature and a higher mixing speed during crystallization. However, the amount of seed particles has no effect on the specific resistance.
The centrifugal filtration time under optimized conditions were compared with the filtration time under the condition employed in an industrial process. It was confirmed that the filtration time of the tested sulfate crystals can be reduced to a half by optimizing of the operating conditions of crystallization.

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Platinum (Pt) particles with high thermal durability are required for ceramic electrodes. In this work, spherical Pt particles coated with Al₂O₃ were prepared by coating pure Pt particles with Aluminum (Al) chelate followed by heat-treatment at 700°C. The thermal-gravimetric analysis of pure Pt particles and coated Pt particles showed that the weight decrease of coated particles is small compared to pure Pt particles. Thermal durability of an electrode made from the Pt particles was measured by repeating heat-treatment at 1500°C. The rate of change in the electrical resistance of an electrode prepared from Al-coated Pt particles was lower than that of the electrode prepared from pure Pt particles.

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A monopole probe and a dipole probe are introduced for one-by-one manipulation of fine particles. The holding force of a particle is controlled by an external power supply. The monopole probe is a tungsten needle, and it can manipulate conducting particles on a metal substrate by applying voltage between the probe and the substrate. It is also capable of welding metal particles on the substrate using it as an electrode. The dipole probe consists of two electrodes, and traps fine particles for any combination of materials of particle and substrate. Both probes can manipulate particles larger than 30μm, which cannot be done by the conventional needle-like probes.

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