Affiliation:
1. Cerel-Ceramic Technologies Ltd.
2. Israel Institute of Technology
Abstract
Cerel has devoted the past several years to the development of prototype microcomponents
for the electronics industry based on EPD processing. The present contribution
summarizes some problems Cerel has experienced in the integration of EPD for metallic silver
particles into a viable production process. In particular, the parameters that need to be controlled
due to the metallic nature of the silver particles have been analyzed.
Selection of a metallic silver powder suitable for EPD is the key factor. An appropriate particle size
and shape, as well as a controlled size distribution, significantly improves the green density of the
deposit. Metallic silver particles in a suspension tend to aggregate, especially when exposed to an
electric field. This leads to premature sedimentation, as well as low green densities for the
electrophoretic deposit. The following factors were found to contribute significantly to preventing
premature sedimentation:
• The replacement of pure silver by palladium-coated silver particles.
• Dispersion preparation in a high viscosity medium of low dielectric constant.
• The presence of steric, electrosteric and ceramic oxide additives in the siver powder
dispersion.
Finally, control of the solids loading and particle size distribution in the suspension, and the
geometrical design of the EPD cell, including the counter-electrodes, were also shown to be
important for the successful electrophoretic deposition of silver particles in the commercial
production of micro-components by EPD.
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
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3. J. Van Tassel, C.A. Randall, J. Mater. Sci., Vol. 39 (2004), pp.867-879.
4. M. Zarbov, I. Schuster, L. Gal-or, J. Mater. Sci., Vol. 39 (2004), pp.813-817.
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