ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Cerel has devoted the past several years to the development of prototype microcomponentsfor the electronics industry based on EPD processing. The present contributionsummarizes some problems Cerel has experienced in the integration of EPD for metallic silverparticles into a viable production process. In particular, the parameters that need to be controlleddue 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 sizeand shape, as well as a controlled size distribution, significantly improves the green density of thedeposit. Metallic silver particles in a suspension tend to aggregate, especially when exposed to anelectric field. This leads to premature sedimentation, as well as low green densities for theelectrophoretic deposit. The following factors were found to contribute significantly to preventingpremature 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 powderdispersion.Finally, control of the solids loading and particle size distribution in the suspension, and thegeometrical design of the EPD cell, including the counter-electrodes, were also shown to beimportant for the successful electrophoretic deposition of silver particles in the commercialproduction of micro-components by EPD
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.314.95.pdf
Permalink
