| 摘要 |
<p><PICT:1030937/C6-C7/1> In a radio frequency plasma flame spraying arrangement, the oscillator circuit is of the tunedgrid, tuned anode type [see Division H3] and the item 14 being sprayed is coupled to the anode circuit via an auxiliary resonant circuit which may comprise a quarter-wave line, 15 or parallel resonant circuit [Fig. 3, not shown]. The anode tank coil 2 is made of concentric copper tubing to allow of water cooling, and terminates in a conically tapered torch lip 3: this is surrounded by an insulating sleeve 4 of polystyrene ending in a nozzle 5. To generate the plasma flame argon is supplied from pressure tank 8 to gas inlet 6 at the rear of sleeve 4. Attached in front of and above nozzle 5 is a powder feed nozzle 9 to which the powder to be sprayed is fed from feeder 10, utilizing carrier gas, e.g. air, nitrogen or argon, from source 12: the spraying of aluminium and its oxide is referred to. The item 4 to be sprayed may comprise a roughened steel plate.</p> |
