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1164 |
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Monday, June 02, 2008, Room 05 2:40 PM New Equipment 2 Latest developments in thermal spray equipment, modern multiple arc plasma guns, optimized powder feeder, new vacuum processes |
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Homogenization of coating properties in atmospheric plasma spraying - technical objectives and first results of a DFG funded research group |
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Karsten Hartz / Institute of Materials Science, Leibniz Universität Hannover, Germany Friedrich-Wilhelm Bach / Institute of Materials Science, Leibniz Universität Hannover, Germany Kirsten Bobzin/ Surface Engineering Institute (IOT), RWTH Aachen, Germany Jochen Schein*/ Institute of Plasma Technology and Mathematics, Universität der Bundeswehr München, Germany Kai Möhwald/ Institute of Materials Science, Leibniz Universität Hannover, Germany Daniel Parkot/ Surface Engineering Institute (IOT), RWTH Aachen, Germany Ivica Petkovic/ Surface Engineering Institute (IOT), RWTH Aachen, Germany Günter Forster/ Institute of Plasma Technology and Mathematics, Universität der Bundeswehr München, Germany Stephan Zimmermann/ Institute of Plasma Technology and Mathematics, Universität der Bundeswehr München, Germany |
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The disadvantage of plasma torches using conventional single cathode techniques is the occurrence of azimuthal and axial instabilities inside the plasma torch. This causes electrical power fluctuations which result in inhomogenieties of the plasma jet enthalpy and with that an uneven plasma particle interaction. Hence, variations in particle properties occur and consequently an uneven coating quality is produced.
Using the triple-cathode technique these electrical power fluctuations were successfully reduced, resulting in a stationary plasma flow. Thus this technique appears to offer the potential to homogenize coating properties. Similar results have been shown for plasma torches with triple anode arrangements.
The goal of this research group is to homogenize properties of plasma spayed coatings using of 3-cathode and 3-anode technologies based on numerical simulations. The approach used is to subdivide the complete APS process into the areas plasma torch, free jet as well as coating formation and characteristics. By simulation of the individual areas and combination with experimental results the corresponding process parameters will be obtained for the desired coating properties. |