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 Na2WO4–WO3 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 μm 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.