Self-passivating (Re,Al)B2 coatings synthesized by magnetron sputtering

Pascal Bliem; Stanislav Mráz; Sandipan Sen; Oliver Hunold; Jochen M Schneider

doi:10.1038/s41598-018-34042-1

Self-passivating (Re,Al)B₂ coatings synthesized by magnetron sputtering

Sci Rep. 2018 Oct 22;8(1):15570. doi: 10.1038/s41598-018-34042-1.

Authors

Pascal Bliem¹, Stanislav Mráz², Sandipan Sen², Oliver Hunold², Jochen M Schneider²

Affiliations

¹ Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074, Aachen, Germany. pascal.bliem@rwth-aachen.de.
² Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074, Aachen, Germany.

Abstract

(Re_0.67Al_0.10)B₂ and (Re_0.74Al_0.11)B₂ solid solution as well as Re_0.85B₂ thin films were deposited by hybrid RF-DC magnetron sputtering. X-ray diffraction (XRD) showed that all films exhibit the ReB₂ (P6₃/mmc) crystal structure. X-ray photoelectron spectroscopy (XPS) analyses performed on atmosphere exposed thin film surfaces suggest that ReB₂ corrodes, consistent with literature, by forming perrhenic acid (HReO₄) already after two days, while (Re_0.74Al_0.11)B₂ forms a self-passivating Al-oxide layer preventing corrosion in a time period ≥ 60 days. Hence, it is evident that Al additions to ReB₂ significantly increase the chemical stability during atmosphere exposure.