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Plasma state in pulsed arc, laser and electron deposition

: Witke, T.; Ziegele, H.


Surface and coatings technology 97 (1997), pp.414-419
ISSN: 0257-8972
Journal Article
Fraunhofer IWS ()
plasma-Diagnostik; Bogentechnologie; PLD; plasma; PVD

Thin coatings can be produced with good hardness and wear protection under the low-pressure processes of plasma enhanced deposition. The aim of these coatings is to reduce mechanical wear, abrasion on tools and to protect the surface of different components against corrosion to guarantee their optical and decorative properties. With arc current, laser beam and a pulsed electron beam of channel spark discharge, it is possible to produce a power density over 10(exp 8) W cm(-2) on a target surface. The advantage of these techniques over other PVD processes like EB evaporation or magnetron sputtering is the characteristic of the plasmas with high energetic excitation and the high kinetic energy of the particles. In particular, these plasma conditions have an influence on the structure of the coatings. In this work, the plasma parameters of the laser deposition, arc deposition and channel spark discharge are compared. These plasma sources are able to produce full ionized plasmas on aluminum and carbon surfaces. The amount of double ionized ions in the plasmas can be over 75 per cent. Experimentally determined electron temperatures in the centers of the different plasmas reach values between 1 and 2 eV. In addition, the average kinetic energy of expanding motion of the ions is in the range 30-250 eV. The process of hydrodynamic expansion of the plasmas will be discussed.