| 摘要 |
<p>Contact plate 11 and Contact base for generating axial magnetic field 12 are made of copper-based alloy such as copper-chromium alloy for example. On the periphery of contact base for generating axial magnetic field 12, Outer circumferential section film 17 is provided. Outer circumferential section film 17 is formed by plasma irradiation of chromium that is a arcing part having a melting point higher than the melting point of contact plate 11.</p> |
