| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a plasma heating device in which the lifetime of an insulating film to cover the external exposed face of a plasma torch is improved greatly without using a special material. Ž<P>SOLUTION: Nozzle cylinders 12, 13 have nozzle outer cylinders 14, 15, nozzle inner cylinders 18, 19, and nozzle tips 20, 21 which close tips of spaces 32, 33 formed between the nozzle outer cylinders 14, 15 and the nozzle inner cylinders 18, 19, and insulating films 30, 31 for preventing a side arc in which a current flows directly between an anode plasma torch 10 and a cathode plasma torch 11 are formed on external exposed faces of the nozzle cylinders 12, 13. The insulating film 30 has an interlayer 30b formed of a mixture of a lowermost layer 30a and an uppermost layer 30c between the lowermost layer 30a composed of a bonding coat material such as Ni-Al and Ni-Cr and the uppermost layer 30a composed of alumina or spinel or mullite. The mixture has a ratio of the bonding coat material in a range of 1/3-2/3 in mass. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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