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

(ReAl)B and (ReAl)B solid solution as well as ReB thin films were deposited by hybrid RF-DC magnetron sputtering. X-ray diffraction (XRD) showed that all films exhibit the ReB (P6/mmc) crystal structure. X-ray photoelectron spectroscopy (XPS) analyses performed on atmosphere exposed thin film surfaces suggest that ReB corrodes, consistent with literature, by forming perrhenic acid (HReO) already after two days, while (ReAl)B forms a self-passivating Al-oxide layer preventing corrosion in a time period ≥ 60 days.