Spectroscopic Characterization of Two Different Microwave (2.45 GHz) Induced Argon Plasmas at Atmospheric Pressure

2005 ◽  
Vol 59 (4) ◽  
pp. 519-528 ◽  
Author(s):  
M. C. García ◽  
C. Yubero ◽  
M. D. Calzada ◽  
M. P. Martínez-Jiménez

A surface-wave-sustained discharge created by using a surfatron device in a tube open to the atmosphere can be used to maintain a microwave (2.45 GHz) plasma at atmospheric pressure at powers of less than 300 W. The TIA ( Torche à Injection Axiale) is a device also producing a plasma that, moreover, permits us to work at high power (higher than 200 W and up to 1000 W). A study of the departure from the thermodynamic equilibrium existing in the argon plasmas created by both devices has been done by using optical emission spectroscopy techniques in order to characterize them and to evaluate their possible advantages when they are used for applied purposes.

2021 ◽  
Vol 11 (5) ◽  
pp. 2275
Author(s):  
Rok Zaplotnik ◽  
Gregor Primc ◽  
Alenka Vesel

A suitable technique for localized surface treatment of solid materials is an atmospheric pressure plasma jet (APPJ). The properties of the APPJ plasma often depend on small details like the concentration of gaseous impurities what influences the surface kinetics. The simplest and often most useful configuration of the APPJ is presented, characterized by optical emission spectroscopy (OES), and results are discussed in view of various papers. Furthermore, results of additional recent papers on the characterization of the APPJ by OES are presented as well. Because the APPJ is operating at atmospheric pressure, even the water vapor traces may significantly alter the type and concentration of reactive species. The APPJ sustained in noble gases represents a source of vacuum ultraviolet (VUV) radiation that is absorbed in the surface of the treated material, thus causing bond scission. The addition of minute amounts of reactive gases causes significant suppression of VUV radiation and the formation of reactive radicals. These radicals such as OH, O, N, NO, O3, and alike interact chemically with the surface causing its functionalization. Huge gradients of these radicals have been reported, so the surface finish is limited to the area reached by the radicals. Particularly OH radicals significantly prevail in the OES spectra, even when using very pure noble gas. They may cause suppression of other spectral features. OH radicals are especially pronounced in Ar plasmas. Their density decreases exponentially with a distance from the APPJ orifice.


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