| 摘要 |
PCT No. PCT/JP94/00270 Sec. 371 Date Aug. 24, 1995 Sec. 102(e) Date Aug. 24, 1995 PCT Filed Feb. 23, 1994 PCT Pub. No. WO94/19137 PCT Pub. Date Sep. 1, 1994A plasma arc torch is provided which has a very long electrode lifetime, even if the number of times that an arc is generated and stopped is great. Improper electric discharge can be effectively prevented, and the lifetime can be increased due to the excellent resistance to heat. For this purpose, a metallic layer is provided in the portion where a pilot arc is generated, and the metallic layer contains at least one metal selected from the group consisting of gold and silver. The metallic layer is provided on the surface of the electrode holder, or on both of a surface of the electrode holder and a surface of the nozzle. Further, at least one of the electrode holder and the nozzle can be formed of aluminum or an aluminum alloy, and after the formation, an anodic oxide film can be formed on the surface thereof.
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