Decomposition Method of N and C-atoms in R (Ar)-N2-CH4 Flowing Afterglows in High Power RF Jet | Chapter 5 | Plasmas Afterglows with N2 for Surface Treatments synthesis 2024

The primary purpose of the study is to investigate the decomposition mechanisms of nitrogen (N) and carbon (C) atoms in a plasma afterglow environment consisting of argon (Ar), nitrogen (N2), and methane (CH₄). One of the major problems in depollution processes using the plasma technique is the analysis and monitoring of the effluent gases. Radiative species in the Ar RF plasma torch with the addition of H₂, CH₄ and CF₄ polluting gases have been analyzed by emission spectroscopy. An efficient etching by F atoms of reactor quartz tube is detected from Si atom emission when a few 10^-3 CF₄ was introduced into the Ar plasma. The Si emission disappeared with H₂ introduction into the Ar - CF₄ gas mixture which has been correlated with HF formation. From C atom emission, it is deduced that CF₄ as CH₄ polluting gases are largely dissociated into the Ar plasma torch. The C-atom density was evaluated from the N-atom density measured by NO titration by considering the part of N+N recombination which populated the N2 (B,v’) radiative states. It is found that the RF 64 MHz plasma jet at 3 kW brought N and C -atoms densities in an afterglow at 3 10^-2s near the atmospheric gas pressure which are respectively ~10¹⁶ cm^-3 and 10¹⁵ cm^-3 are 10¹ and 10² higher than in 2450 MHz afterglows at about 100 W and 10 Torr. The gas temperature determined from the CN and N2 rotational systems is 3200± 200 K in the RF torch and 700± 100 K in the afterglow at 3 10^-2 s.

 

Author (s) Details

 

André Ricard
LAPLACE, Université de Toulouse, CNRS, INPT, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 9, France.

 

Simon Cavadias
IRCP 2PM—Chimie-Paristech—UMR 8247, 11 rue P. et M. Curie, 75231 Paris Cedex 05, France.

 

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-93-5/CH5