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DF: Fachverband Dielektrische Festkörper

DF 19: Poster 2

DF 19.7: Poster

Mittwoch, 13. März 2013, 15:00–17:30, Poster B2

Kelvin probe force microscopy investigations of the contact charging of single crystalline insulators — •Monika Mirkowska^{1, 2}, Markus Kratzer², Christian Teichert², and Helmut Flachberger¹ — ¹Chair of Mineral Processing, Department Mineral Resources and Petroleum Engineering, Montanuniversität Leoben, Austria — ²Institute of Physics, Montanuniversität Leoben, Austria

Detailed knowledge about the contact charging behavior of dielectric materials is of great interest for technological applications like tribocharging separation of mineral particles. The underlying mechanisms are still not well understood. Here, an attempt is made to study the electric charging of well-defined surfaces (quartz and calcite monocrystals) upon contact with a conventional AFM tip. Measurements were performed in a fluid cell under controlled temperature (30 * 100 °C) and relative humidity (4 * 40 % RH) conditions. Kelvin probe force microscopy was applied to verify the electrostatic characteristic of the surfaces before and after contact charging. Both, tribocharging due to rubbing and static contact charging with applied tip bias have been investigated. The influence of humidity, contact time, contact force, and probe bias has been studied. The relative humidity turned out to play a key role in the charging process.