Diffusion assisted reactive coating for plasma resistant tungsten surfaces

Abstract

Plasma facing surfaces are prone to corrosion due to the aggressive environment. Due to their high temperature and chemical stability, tungsten parts are commonly used for these applications. To further improve the plasma resistance of tungsten, a method was developed to provide the parts in close proximity to the plasma with a coating containing tungsten carbide or tungsten boride. In order to achieve fully covered surfaces, carbon and boron were deposited by a suspension technique onto the tungsten component at room temperature. During downstream heat treatment, diffusion and subsequent chemical reactions take place and a well adhering carbide or boride coating is formed. Such coatings show no spalling or bulging. Analyses of microstructure and phase discrimination in the coating were performed by EBSD (electron backscatter diffraction). The manufacturing and characterization of such carbon and boron containing surface layers are presented and discussed in this paper.