Joachim Heberlein

University of Minnesota, Department of Mechanical Engineering, Minneapolis, MN 55455, USA
jvrh@me.umn.edu

The primary characteristics of thermal plasmas which make them attractive for materials processing are: (1) the high energy density allows modification of practically any material, and (2) the temperature and heat transfer can be controlled independently of the oxygen potential of the medium or the material to be processed. The consequences are fast processing rates and good control over the co-products including off-gases. Plasma processing in the metallurgical industry is one of the oldest applications of plasma technology, but only in the recent past have new developments started to make full use of the advantages offered by thermal plasmas, such as low gas flow rates. Concern for effects of materials processes on the environment have led to further spreading of thermal plasma processing applications and have led to the development of plasma waste treatment technologies. Plasma synthesis of materials allows the use of vapor phase reactions, and has recently gained in importance with the development of nanophase materials. The fastest growing application of thermal plasma technology is in the field of coatings, since coatings can increase the functional value of a material. An example os the use of plasma sprayed thermal barrier coatings for power generating equipment and in the automotive industry. Lastly, a combination of plasma synthesis and coating technology is provided by thermal plasma chemical vapor deposition, a process which can produce coatings of high functional value at a rapid rate. Deposition of diamond films for a variety of applications is the primary example of this emerging process. This presentation will review the recent advances in the ares of plasma metallurgy and waste processing, plasma synthesis and plasma coating technology.