Smooth surface treated by low-pressure arc discharge

Low-pressure arc cleaning is a process for removing an oxide layer. Currently, chemical and mechanical processes are typically used to remove such layers. However, both methods present severe problems such as liquid wastes, dust, and noise. In the case of low-pressure arc cleaning, waste comes from only one place—the oxide layer. In addition, because the cathode spot has very high temperature, it is sufficient to remove the oxide layer. This paper describes the removal of the nanometer-thick oxide layer from a thin metal plate. The oxide layer was removed and a smooth surface whose respective arithmetical mean height (Ra) and average length of outline curve element (Rsm) are 0.04 and 6.4 μm was obtained using an oxide layer of 27 nm. Those results depend on the oxide layer thickness. Therefore, although the surface is cratered and rough after cathode spot treatment on the chemical oxide layer (6.7 nm), a smooth surface is obtainable after cathode spot treatment on the thermal oxide layer (27 and 157 nm).