Influences of CF₄ content on discharge characteristics of argon plasma jet under atmospheric pressure

In order to produce low tempreture plasma jet containing high active fluorine and to optimize its efficiency as well, the effects of CF₄ content on the discharge characteristics of Argon plasma jet under atmospheric pressure are investigated by means of electrical properties measurements, including the voltage-current waveforms and the Lissajous figures, and optical properties measurements, including light-emission images and optical emission spectra. The trends of the main discharge parameters, such as discharge power, transferred charges, and the spectrum line intensities of the main particles in the discharge, changing with CF₄ contents are calculated from the measured electrical and optical characteristics. And the experimental results are analyzed from the view point of discharge ionization process. Results show that with the increase of CF₄ content within the Ar/CF₄ plasma jet, the number of current pulses reduces, the pulse duration time and jet length become shorter, the lighting emission intensity becomes weaker, and the discharge power and the transferred charges also decrease. The spectrum line intensities for other particles except F decrease with the increase of CF₄ content. The spectrum line intensity of F achieves its maximum value when the CF₄ content is 4%, which suggests that the amounts of F containing groups is the most at this case. Under this condition the plasma jet can be used for hydrophobic surface modification of the insulation materials to achieve preferable results.