Oil removal from metals by linear multi-orifice hollow cathode

A linear multi-orifice hollow cathode oxygen plasma source has been developed for oil removal from moving metal surfaces. The source is a linear set of plasma jets created at each orifice by a magnetically enhanced and directed d.c. hollow cathode discharge. Vacuum and electrical characteristics of the source are presented and discussed. Substantial reduction of carbon-containing contamination on a metal surface after exposure to the oxygen plasma is demonstrated by using in situ XPS. The surface cleanliness of a metal sheet is evaluated by the contact angle with water. This angle is desired to be 10 deg or less. The contact angle dependence on plasma dose density is described for plasma atmospheres of O sub 2 and O sub 2 +CF sub 4 and two different aluminium foil thicknesses.