AVS 51st International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS-ThM

Paper PS-ThM8
Atmospheric He-O@sub 2@ DBD Plasma for Steel Decontamination

Thursday, November 18, 2004, 10:40 am, Room 213A

Session: Atmospheric and Microdischarges
Presenter: E. Michel, Universite Libre de Bruxelles, Belgium
Authors: E. Michel, Universite Libre de Bruxelles, Belgium
E. Silberberg, Arcelor Group
F. Reniers, Universite Libre de Bruxelles, Belgium
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The use of a DBDs allows the stabilization of cold plasmas at atmospheric pressure which are of a great interest for industrial surface treatments because they do not request expensive vacuum systems. Contrary to wet treatments traditionally used to clean steel surfaces, the plasma treatments are environmental friendly, as they do not produce toxic waste. Standard steel surfaces were covered with various amounts of oil using dip coating. The contaminated surfaces were treated using atmospheric pressure plasma in a DBD. In our configuration, the hot electrode only is covered with the dielectric, whereas the other electrode being the sample. Voltages between 1 to 4 kV were applied between the electrodes, at a frequency varying between 5 and 30 kHz. The plasma gas consisted in a mixture of He-O@sub 2@ (2 to 10 % oxygen), at atmospheric pressure. The plasma chemistry was characterized using optical emission spectrometry (OES). The electrical characteristic of the plasma were recorded as a function of the applied voltage, frequency and gas composition. The transition parameters between the homogenous glow discharge and the filamentary one were established for our configuration. The kinetics of decontamination was studied by Auger electron spectroscopy (AES) and infrared spectroscopy (IRRAS- FTIR). The effect of the frequency, the applied voltage, the discharge current, the initial amount of contamination and the plasma gas composition on the kinetics of oil degradation was studied and discussed. The resulting surface state of steel was investigated using AES and X-ray photoelectron spectroscopy. Finally, a macroscopic model for the kinetics of decontamination of steel surfaces by He-O@sub 2@ atmospheric plasmas is proposed.