Properties of tungsten coatings deposited onto fine grain graphite by different methods

Tungsten coatings on fine grain graphite with film thicknesses in the micro meter range were prepared by three different methods: electron beam evapora tion, magnetron sputtering, and arc deposition. They were compared with res pect to properties relevant for the application of such systems in the nucl ear fusion experiment ASDEX Upgrade. The content of light impurities was de termined by sputter XPS. A deposition parameter study for magnetron sputter ed coatings is presented; the formation of compressive stress is identified to be the major drawback of this method. Furthermore, experiments with the rmal loading by an electron beam facility are presented. (C) 2001 Elsevier Science BN. All rights reserved.