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Improved Plasma Spray Torch Stability Through Multi‐Electrode Design
Author(s) -
Schein J.,
Zierhut J.,
Dzulko M.,
Forster G.,
Landes K. D.
Publication year - 2007
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.200710064
Subject(s) - plasma torch , anode , materials science , cathode , plasma , electrode , jet (fluid) , thermal spraying , residence time distribution , plasma arc welding , coating , electric arc , current (fluid) , analytical chemistry (journal) , mechanics , composite material , flow (mathematics) , chemistry , thermodynamics , physics , quantum mechanics , chromatography , welding
Coating production by thermal plasma spray is dependent on the residence time of particles in the plasma jet produced by the gas flow inside a plasma torch. To ensure a high fraction of well‐molten particles to be accelerated towards the substrate a long reproducible residence time is needed. This can be achieved by a long plasma jet with little or no temporal variation in length and temperature. While single electrode plasma torches need an unstable attachment of the anodic arc root in order to avoid excess erosion, which also causes an unstable plasma jet, multi‐electrode torches allow operation with fixed anode attachments by subdividing the anode current by the number of electrodes used, and thereby thus reducing the power input for each separated arc root. Once the steady anode attachment has been obtained the produced plasma jet exhibits a steady characteristic, but also looses rotational symmetry. The separation can be achieved by using either multi anode or multi cathode geometry with appropriate electrical control. Both version have been produced with 3 electrodes each resulting in two systems known as the Delta Gun (3 anodes) and Triplex (3 cathodes). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)