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Generation of ultrafine particles by spark discharging.

Aerosol Sci. Technol. 38, 228-235 (2004)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Ultrafine carbon, metal, and metal oxide particles were generated with a commercially available spark generator designed for the production of carbon particles. Aerosols with number concentrations up to 107 cm−3 were produced at flow rates up to 150 lpm. Lognormal size distributions with modal diameters in the range of 18–150 nm and geometric standard deviations of about 1.5 were obtained. The chemical composition, size, number concentration, morphology, and surface area of the particles were varied, and the generation of particles with fixed characteristics could be maintained over many hours. The particle characteristics, however, could not be varied independently. For a certain chemical composition only size and number concentration were variable; morphology and surface area were fixed regardless of particle size. The particles grow by coagulation of primary particles formed by nucleation. The coagulated particles can either stick together and maintain their identity or fuse together and lose their identity. Each material used for the generation of ultrafine particles is thus associated with a certain morphology and surface area: silver with a low mass-related BET surface area (20 m2 g−1), metal oxides and iridium with a low-to-intermediate BET surface area (50 m2 g−1 for cadmium oxide, 120 m2 g−1 for iridium, and 300 m2 g− 1 for ferric oxide), and carbon with a large BET surface area (750 m2 g−1). Iridium, on the other hand, has a huge volume-related BET surface area (2800 m2 cm−3). It was not possible to generate ultrafine carbon particles without contaminations with the generator. However, these contaminations could be decreased in this study from 25% to 6% by replacing organic components of the generator by pure inorganic components.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
ISSN (print) / ISBN 0278-6826
e-ISSN 1521-7388
Quellenangaben Volume: 38, Issue: 3, Pages: 228-235 Article Number: , Supplement: ,
Publisher Taylor & Francis
Non-patent literature Publications
Reviewing status Peer reviewed