Papers by Author: Shigeo Hayashi

Abstract: Electrophoretic deposition (EPD) and infiltration (EPI) behavior of a natural zeolite (clinoptilolite, produced in Akita prefecture, Japan) particles on/into a steel and a porous glass substrates were investigated for the purpose of the environmental purification. The obtained deposit of the zeolite prepared by the EPD was less durable against peeling off compared with the EPI process, but it was improved by use of silica sol particles as a binder. Ion uptake efficiency of the EPD sample was superior to that of the EPI sample, that will be caused by the shape factor of the zeolite particle deposit.

Abstract: Stabilized zirconia is a common material for oxygen sensors as a solid electrolyte. The electrophoretic deposition (EPD) behavior of 8Y-YSZ (Yttria-stabilized zirconia with 8 mol% Y2O3) powder was investigated on stainless steel and carbon based substrates. This study will be the starting point for the fabrication of complex shaped (even in micro-scale) YSZ based devices. Ethanol + HNO3 based suspensions were used for the EPD experiments and three different YSZ powders were deposited, one commercially available powder and two own-made coprecipitated powder. The latter powders were calcined at respectively 900 and 1200°C. The concentration of the suspension was 3 g/300 cm3, and a small amount of HNO3 solution was added as a dispersant. DC electric field of 100-200 V/15 mm was applied between parallel electrodes. It was found that on stainless steel electrodes the calcined own-made coprecipitated powder showed the best best deposition properties, whereas the commercial YSZ powder showed the best deposition properties on carbon electrodes. These experimental results are discussed with regard to some powder properties (e.g. particle size distribution and packing behavior) and the adhesion between the particles and the substrate.