Application of carbon-aluminum nanostructures in divertor coatings from fusion reactor

摘要

Nanostructured carbon materials have increasingly attracted the interest of the scientific community, because of theirfascinating physical properties and potential applications in high-tech devices. In the current ITER design, the tiles madeof carbon fiber composites (CFCs) are foreseen for the strike point zone and tungsten (W) for other parts of the divertorregion. This choice is a compromise based mainly on experience with individual materials in many different tokamaks.Also Carbon-Aluminum composites are the candidate material for the First Wall in ITER.In order to prepare nanostructured carbon-aluminum nanocomposite for the divertor part in fusion applications, theoriginal method thermionic vacuum arc (TVA) was used in two electronic guns configuration. One of the mainadvantages of this technology is the bombardment of the growing thin film just by the ions of the depositing film.Moreover, the energy of ions can be controlled. Thermo-electrons emitted by an externally heated cathode and focusedby a Wehnelt focusing cylinder are strongly accelerated towards the anode whose material is evaporated and brightplasma is ignited by a high voltage DC supply.The nanostructured C-Al films were characterized by Scanning Electron Microscopy (SEM), Transmission ElectronMicroscopy (TEM). Tribological properties in dry sliding were evaluated using a CSM ball-on-disc tribometer. Thecarbon - aluminum films were identified as a nanocrystals complex (from 2nm to 50 nm diameters) surrounded byamorphous structures with a strong graphitization tendency, allowing the creating of adherent and wear resistant films.The friction coefficients (0.1 - 0.2, 0.5) of the C-Al coatings was decreased more than 2-5 times in comparison with theuncoated substrates proving excellent tribological properties. C-Al nanocomposites coatings were designed to haveexcellent tribological properties while the structure is composed by nanocrystals complex surrounded by amorphousstructures with a strong graphitization tendency, allowing the creating of adherent and wear resistant films.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.