Discharge Characteristics of Ar/NH3/H2O Plasma Jet Under Atmospheric Pressure

To enhance the treatment effects of the atmospheric pressure plasma jet (APPJ) in the fields of material surface treatment, environmental protection, and disinfection sterilization, etc., NH3/H2O were added to the Ar APPJ to improve the activity of the APPJ. The optical emission spectral intensities of NH, OH and O and the length of the plasma plume were investigated at various applied voltages and NH3/H2O ratios by optical emission spectra diagnosis and light-emission images observation. The voltage-current waveforms and Lissajous figures were also recorded correspondingly. Results showed that the main species produced by APPJ in Ar/NH3/H2O included Ar, N2, NH, OH, and O. As the applied voltage increased, the emission spectral intensities of NH, OH and O, the length of the plasma plume, discharge power and transported charges all increased. When the added NH3 reached 0.012 5% in the Ar/NH3 mixed gas, the emission spectral intensity of NH reached the maximum.,When H2O was added under this condition, it was found that the emission spectral intensities of OH and O reached the maximum values when the water vapor content was 0.25% and the emission spectral intensities of OH and O increased by 104.4% and 55.8% as compared with those of APPJ in Ar/NH3, while the emission spectral intensity of NH decreased by 18.7%. The overall emission spectral intensities of the oxidizing particles (NH, OH and O) in Ar APPJ reached the maximum, and it should be more favorable for applications in materials hydrophilic modification and disinfection sterilization, etc. © 2019, High Voltage Engineering Editorial Department of CEPRI. All right reserved.