The Influence of Interface Characteristics on the Adhesion/Cohesion of Plasma Sprayed Tungsten Coatings

Abstract

Abstract:Tungsten is the prime candidate material for plasma facing components of future fusion devices. Plasma spraying, with its ability to coat large areas, including non-planar surfaces, with a significant thickness, is a prospective fabrication technology for components subject to moderate heat loads, e.g., the first wall of the Demonstration Reactor (DEMO). The functionality of such coatings is critically dependent on their adhesion to the underlying material. This in turn, is influenced by a variety of processing-related factors, chief among them being the state of the interface. In this study, the effects of two factors-surface roughness and the presence of thin interlayers-were investigated. Two different levels of roughness of steel substrates were induced by grit blasting, and two thin interlayers-titanium (Ti) and tungsten (W)-were applied by physical vapor deposition prior to plasma spraying of W by a Water Stabilized Plasma (WSP) torch. Coating adhesion was determined by a shear adhesion test. The structures of the coatings and the interfaces, as well as the characteristics of the fractured surfaces, were observed by SEM.

Effect of Substrate Type on the Fractal Characteristics of AFM Images of Sputtered Aluminium Thin Films

“…For instance, Takadoum and Bennani reported that titanium nitride (TiN) thin films deposited on rough steel substrates have poor adhesion [1]. In other cases, surface roughness has been shown to increase adhesion and cohesion between plasma-sprayed coatings and substrates [2,3]. For microelectronic applications, surfaces of Indium tin oxide (ITO) films should be atomically smooth to avoid electrical leakages; in fact, for such applications the interface width should be ~ 1 nm [4], [5].…”

An oxygen plasma treated poly(dimethylsiloxane) bioscaffold coated with polydopamine for stem cell therapy

“…Hence, we stored our PDMS bioscaffolds in de-ionized water immediately after oxygen plasma treatment. As oxygen plasma treatment makes the PDMS surface rough [22] and brittle [56], it has the advantage of increasing the bonding strength between a coating layer and the underling PDMS bioscaf-fold [57]. Furthermore, the addition of another layer on top of the oxygen plasma treated PDMS surface has also been shown to prevent its hydrophobic recovery by mechanically stabilizing the surface [56].…”

Overview of processing technologies for tungsten-steel composites and FGMs for fusion applications

“…Several FGM fabrication techniques were reviewed in [21]. The tungsten-steel bonding can be achieved by a number of techniques, including those using a third material as a bonding interlayer, instead of an FGM [22,23].…”