Tungsten-Steel Functionally Graded Coatings for Nuclear Fusion Applications Manufactured by Cold Gas Spraying

In nuclear fusion reactors, the first wall is the name given to the surface which is in direct contact with the plasma. A part of it is the divertor which is a device that removes fusion products from the plasma and impurities that have entered into it from the vessel lining. It is covered with water cooled tiles which have to withstand high temperatures and high heat fluxes. Moreover, resistance to neutron bombardment, low tritium absorption and low hydrogen permeation are additional demands. One materials concept under research is the application of a Reduced Activation Ferritic Martensitic Steel (RAFM) as a structural material with a tungsten protective coating. Since there is a considerable thermal mismatch between, a functional-graded materials concept was proposed

Investigations and New Physical Behaviour of Special DC-Plasma Generator Mettech "Axial III"

The use of plasma generators for thermal surface coating has grown enormously in the field of thermal insulation and wear resistant coatings, especially with regard to deposition of refractory oxide ceramic layers using powders such as aluminum oxide, alumina / titania, zirconia and chromium oxide. Nonetheless, innovative plasma sources are still being developed to provide more-efficient, tailor-made solutions due to their specific characteristics. A brief overview of the DC plasma generator Mettech “Axial III” are shown, which generator are allowed to use the central injection (advantage for suspension applications). In this paper first diagnostic results characterized the physical behaviour and special plasma symmetry, which can be described by three partial plasma jets. Thereby computer tomography (CT), high speed camera investigations coupled with time-adjusted current-voltage measurements, particle parameter detections and first resulting coatings are presented and discussed. The complete paper concludes with an outlook for future diagnostic measurements and possible future applications for this DC-plasma torch