Experimental investigation of the electrical characteristics and initiation dynamics of pulsed high-voltage glow discharge

Pulsed high-voltage glow discharge, a process that falls between conventional plasma ion implantation and plasma nitriding, is a potentially effective surface treatment technique. The electrical characteristics and initiation dynamics of the process are experimentally investigated in this work. The discharge behaviour is found to depend on the applied voltage, gas pressure, pulse duration, and pulsing frequency. The voltage-current characteristics basically obey the collisionless Child-Langmuir relationship, and the discharge current varies substantially with the applied voltage and gas pressure in the high-voltage, high-pressure domain. The seed plasma before each glow discharge pulse affects the initiation mechanism regardless of whether it is sustained by an external plasma source or it is simply the residual plasma of the afterglow after the voltage pulse has been turned off. Our results also disclose that the presence of an initial plasma before the glow discharge is ignited has a large impact on the initiation time of the glow discharge but has only a slight effect on the steady-state current.