G. Mueller¹ , V. Engelko² , H. Bluhm¹, A. Heinzel¹, G. Schumacher¹, D. Strauss¹,

A. Weisenburger¹, F. Zimmermann¹, V. Shulov³, N. Notchovnaia³

Material surface treatment by intense large area pulsed electron beams offers a wide range of applications for the improvement of material surface properties such as wear, corrosion and oxidation resistance. The treatment involves rapid melting of a material surface layer followed by rapid quenching due to heat conduction into the bulk unaffected material.

The pulsed electron beam facilities GESA I and GESA II, have been designed especially for large area surface treatment. They offer the possibility to melt the surface of materials to a depth of 10-100 µm. The beam parameters are: electron energy 50-400 keV; current 200-500 A; pulse duration 5-250 µs; maximum power and energy density at the target 6 MW/cm and 500 J/cm², resp..

Both facilities were developed in cooperation between Efremov Institute St. Petersburg, Russia and the Research Center Karlsruhe (FZK), Germany and operate at FZK, GESA I since 1996 and GESA II since 2000, with the following technological applications:

• improvement of high temperature oxidation resistance of MCrAlY coatings and bonding stability of thermal barrier coatings (TBC) on MCrAlY coated gas turbine blades,
• increasing operation temperature and time of steels as structural materials in liquid lead and lead bismuth alloys by surface alloying of elements which form stable protective oxide scales,
• hardening of surface and increase of their wear resistance by causing metastable hard structures preferably with nano-crystalline grain sizes,
• improvement of resistance against sea water corrosion and high cycle fatigue of aircraft turbine blades by surface restructuring.

The present paper describes after a short introduction to the GESA facilities examples and results of the technological applications.