Properties of Electrodeposited Tungsten Coatings on Graphite Substrates for Plasma Facing Components

Abstract

Tungsten coating on graphite substrate is considered as one of promising candidate materials of plasma facing components. In this study, tungsten coatings on graphite substrate were successfully prepared by direct current (DC) and pulse current (PC) electrodeposition methods in Na 2 WO 4 -WO 3 molten salt under the air atmosphere. Pores were found on the surfaces of the tungsten coatings produced by DC electrodeposition method. For the coatings fabricated by PC method, compact and smooth tungsten coatings were successfully obtained. The crystal structure, morphology, density, microhardness, adhesive strength, oxygen content and the thermal conductivity of the coatings fabricated by PC method were investigated. The obtained tungsten coatings had a body centered cubic structure. After electro-deposition for 100 h, the thickness of the tungsten coating reached 810.02 ± 10.40 lm and the oxygen content was 0.03 wt%. The thermal conductivity of the tungsten coating was 134.29 W m -1 K -1 . The density of the tungsten coating was 18.83 g cm -3 . The hardness of the coating was 492.0 ± 7.8 HV. After deuterium plasma irradiation, the tungsten coatings were prone to blistering.

Combinatorial Discovery of Irradiation Damage Tolerant Nano-structured W-based alloys

“…The W-based HEAs did not contain irradiationinduced dislocation loops and had negligible irradiation hardening. Processing techniques have been developed to fabricate the ultra-fine grained W at large scales [28] and deposition techniques were suggested to produce nanostructured coatings for PFMs [29,30] Although nanostructured W-alloys seem promising as PFMs, limited combinations of composition-microstructure have been explored. Irradiation damages of vast combinations of composition and microstructure need to be investigated in order to deepen our understanding on the irradiation damage tolerant materials and to discover novel alloys with the ideal set of properties.…”

Effect of Electron Beam Remelting Treatments on the Microstructure and Properties of Atmospheric Plasma Sprayed Tungsten Coatings

“…It is hard to use W block directly for the first wall as it's a brittle feature. At present, the W-wall is covered by a thin W coating on graphite and carbon fiber composite tiles, and these W coatings are commonly fabricated by traditional deposition techniques (Ref [9][10][11], among which atmospheric plasma spraying (APS) technique has attracted much more attention since its high deposition efficiency, flexible deposition shapes, in-situ repair and cost-effective (Ref 12 -14). However, with regard to the application of the atmospheric plasma-sprayed W coatings, there are still many problems to be solved, such as high porosity and oxide content, which can significantly reduce the mechanical erosion and corrosion resistance and influence the quality of the sprayed coatings (Ref 15,16).…”