Effect of Pressure on the Behavior of Cathode Spots in Oxide Removal by Arc Discharge

Cathode Spot Behavior Variation in Oxide Layer Removal Caused by Potassium Hydroxide Pre-treatment

“…Because our previous work showed that the cathode spot behavior was affected by the larger pressure difference, the pressure effect can be neglected in the present work. 11,14) Consequently, cathode spot behaviors of two types are identifiable, designated herein as slow cathode spots (SCS) and fast cathode spots (FCS). The change between these two-type behaviors seemed to occur discretely.…”

“…The motion of the cathode spot while removing the oxide layer is influenced strongly by two factors: discharge pressure and the oxide-layer surface states before cleaning. [8][9][10][11] Especially, it has been recognized that the work function change of the oxide layer surface causes different behavior of cathode spots and engenders decreases in both the roughness and heat-affected layer thickness of the cleaned metal surfaces when an aqueous solution of potassium hydroxide (KOH) is applied to the oxide layer surface before VAC. 12,13) Although the detailed mechanism has not been unveiled yet, this phenomenon must be a key to understanding the roles of the cathode spots in VAC.…”