Deposition, Morphological, and Mechanical Evaluation of W and Be-Al2O3 and Er2O3 Co-Sputtered Films in Comparison with Pure Oxides

Abstract

Compact and defect-free high melting point oxide strengthened metallic matrix configurations are promising to resolve the hydrogen permeation and brittleness issues relevant to the fusion research community. Previous studies on oxide addition to metallic matrix demonstrated a mitigation in brittleness behavior, while deposition techniques and material configurations are still to be investigated. Thus, here, we report the structural, morphological, and mechanical characterization of metal-oxides thin layers co-deposited by radio frequency (RF)and direct current (DC) magnetron sputtering. A total of six configurations were deposited such as single thin layers of oxides (Al2O3, Er2O3) and co-deposition configurations as metal-oxides (W, Be)—(Al2O3, Er2O3). The study of films roughness by atomic force microscopy (AFM) method show that for Al2O3 metallic-oxides is increased to an extent that could favor gaseous trapping, while co-depositions with Be seem to promote an increased roughness and defects formation probability compared to W co-depositions. Lower elastic modulus on metal-oxide co-depositions was observed, while the indentation hardness increased for Be and decreased for W matrix configurations. These outputs are highly relevant for choosing the proper compact and trap-free configuration that could be categorized as a permeation barrier for hydrogen and furtherly studied in laborious permeation yield campaigns.

Surface, Structural, and Mechanical Properties Enhancement of Cr2O3 and SiO2 Co-Deposited Coatings with W or Be

“…Depositions were carried out in a conventional magnetron sputtering facility in codeposition configuration integrating magnetrons powered up with RF power sources for oxides targets and DC power sources for the metallic targets. Details regarding the experimental configuration were disseminated elsewhere [30].…”

“…The coatings were deposited on an austenitic 304L stainless steel substrate, often being used in permeation measurements [29]. Moreover, the experimental plan was based on the previously established validation protocol which correlates the configuration of the layers to the mechanical properties (i.e., adhesion, hardness), surface morphology (i.e., roughness), chemical state, and crystalline structure, all applied to (W, Be)-(Al 2 O 3 , Er 2 O 3 ) configurations [30]. Hereinafter, the same protocol is applied for (W, Be)-(Cr 2 O 3 , SiO 2 ) configurations, expanding the scientific insight regarding the structural integrity while contributing to the development of dense and compact coatings.…”