Oxide-Layer Thickness Effect for Surface Roughness Using Low-Pressure Arc

Low-pressure arc cleaning is a process for removing an oxide layer. Currently, chemical and mechanical means are typically used to remove such layers. However, both methods present difficulties such as a liquid waste, dust, and noise. Regarding the low-pressure arc cleaning, waste comes from one source: the oxide layer. In addition, the cathode spot has very high temperatures that are sufficient to remove the oxide layer. This paper describes the removal of the nanometer-thick oxide layer from a thin metal plate. An oxide layer of 27-157 nm was removed, thereby, obtaining a smooth surface whose respective arithmetical mean height (R_a) and average length of an outline curve element (R _sm) are 0.04 and 6.4 mum. In that case, R_a and R _sm increased with an increasing oxide-layer thickness at 397-1680 nm. Those results depend on the oxide-layer thickness. Therefore, although the surface is cratered and rough after a cathode-spot treatment on the chemical oxide layer (6.7 nm), a smooth surface is obtainable after the cathode-spot treatment on the thermal oxide layer (27, 66, and 157 nm). Surface roughness depends on the processing time to produce one crater, which depends on the oxide-layer thickness