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High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes)

An International Journal

ISSN for PRINT: 1093-3611

Institutional price:	$604.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2005, Volume9

162 pages

DOI: 10.1615/HighTempMatProc.v9.i1

Issue price - $144.00

CHARACTERISATION OF PLASMA-SPRAYED BORON CARBIDE AND TUNGSTEN LAYERS FOR FUSION APPLICATIONS

S. Lindig
Max-Planck-Institut fur Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching, Germany

V. Alimov
Max-Planck-Institut fur Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching, Germany

H. Bolt
Max-Planck-Institut fur Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching, Germany

B. Boswirth
Max-Planck-Institut fur Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching, Germany

H. Greuner
Max-Planck-Institut fur Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching, Germany

T. Huber
PLANSEE AG, A-6600 Reutte / Tirol, Austria

G. Matern
Max-Planck-Institut fur Plasmaphysik, Euratom Association, Boltzmannstr. 2, D-85748 Garching, Germany

ABSTRACT

In nuclear fusion devices plasma-facing materials (PFM) have to sustain extreme environments. The first wall of fusion experiments or future power plants is loaded with thermal radiation and high-energy particles, eroding the wall material. In current experiments low-Z-materials such as graphite and carbon composites are preferred PFM, but basic disadvantages are the high erosion rate and accumulation of hydrogen. For the new WENDELSTEIN 7-X fusion experiment (W7-X), now under construction at Greifswald (Germany), 70 m² of water-cooled wall protection will be coated with B₄C layers by vacuum plasma spraying (VPS). VPS provides the required high purity of coating materials and is an effective industrial method. The thermal expansion mismatch of the ceramic B₄C coating and stainless-steel (SS) substrate and, the high processing temperature require an interlayer to reduce residual stress. An interlayer made of SS mixed with B₄C has been successfully developed. An alternative high-Z PFM with very low erosion is tungsten, which shows good plasma-physical and thermo-mechanical behaviour in fusion experiments. The VPS-B₄C technology developed is transferable to coatings of W on SS. Tungsten will possibly be employed as a protective material for the first wall in the next fusion experiment, ITER.