Experimental investigation on the Ar/NH3, He/N2 plasma jet

Summary form only given. Atmospheric pressure plasma jets (APPJ) in mono-gas have been investigated widely by different groups. Some works about the plasma jet in mixture gases ambient are also conducted in the field of polymer materials surface modification. However, the property and mechanism of APPJ in mixture gases ambient are not yet clear. In the work, the APPJs that were generated by using co-axis double ring electrodes¹ in two kinds of mixture gases ambient which are Ar/NH₃ and He/N₂, respectively, have been investigated. Interesting phenomena were observed when a little ammonia was added into the argon or a little nitrogen was added into the helium. In pure argon plasma jet (Ar 3slm, slm means the standard liter per minute), the plasma plume only appears at downstream of the ground electrode. However, keep the flow rate of Ar 3slm, like-glow plume appears at both the upstream of the powered electrode and the downstream of the ground electrode when change the flow rate of ammonia from 0sccm to 27.7sccm (sccm means standard cube centimeter per minute). Furthermore, the plume at upstream of the powered electrode gets longer (reaching the longest length at NH₃ of 0.5sccm) and then shorter. While the plume at downstream of the ground electrode gets shorter continuously and finally disappears at NH₃ of 17.7sccm. In the case of He/N₂ (He 3slm, N₂ changing from 0sccm to 27.8sccm), the plasma plume at upstream of the ground electrode is very long only when the flow rate of N₂ is very little, such as in the range of 0sccm to 0.1sccm. When the flow rate increases to a certain value, the plasma plumes outside of both electrodes get shorter. Moreover, the electrical characteristics of these two kinds of plasma jets are also probed.