9. Conclusion

Since the 1970s, thermal plasma applications at powers below 400 kW have been developed for cutting, welding, reloading, spraying, particle spheroidization, spectrochemical analysis, and in recent years for nanometric powder synthesis, plasma-assisted CVD deposition and zone fusion purification.

A great deal of progress has been made in several areas:

• improved torch design, in particular to limit electrode wear;

• creation of new torches, e.g. arc-spray torches for :

  • axial particle injection,

  • shooting inside engine cylinders,

  • reduce bow foot fluctuations,

  • operate in a controlled atmosphere with chamber pressure down to 1 mbar,

  • ...