| 摘要 |
PURPOSE:To prevent drop of the re-arcing probability while the fusion deposit resistance is well maintained, by specifying the respective contents of Cr, Bi, Cu, and giving a specific dimension to Cr particles appearing at the contact section structure. CONSTITUTION:A Cu-Cr-Bi material for a contact of a vacuum valve is prepared so that the Cr content ranges 20-60wt.% and the Bi content corresponds to 0.05-1.0wt.% of the Cu content, and that a Cr particle appearing at the contact, section structure has a specific circumference ratio ranging 1.0-1.3, wherein the specific ratio means that of the actual circumferential length to the circumferential length of an ideal circle having the same area as the Cr particle section area. Thereby the withstand voltage and re-arcing probability can be obtained substantially the same as those of the Cu-Cr material for contacts while the fusion deposit resistance is well maintained. |
