Phase formation of B2-RuAl during annealing of Ru/Al multilayers

• Published in: Intermetallics Vol. 18; no. 8; pp. 1507 - 1516
• Main Authors: Zotov, N., Woll, K., Mücklich, F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2010
• Subjects: A. Aluminides, miscellaneous; Aluminum; Annealing; B. Diffusion; C. Thin films; D. Phase interfaces; Diffusion; Diffusion layers; F. Diffraction; Multilayers; Roughness; Scanning electron microscopy; Tantalum; C. Thin films; D. Phase interfaces; A. Aluminides, miscellaneous; B. Diffusion; F. Diffraction
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2010.04.001

The formation of B2-RuAl from Ru/Al multilayers (MLs) with an average MLs composition of Ru 47Al 53 and modulation periods Λ up to 22.4 nm was studied by in-situ X-ray diffraction (XRD), differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy. The as-deposited MLs with Λ < 4.5 nm grow epitaxially with relatively small roughness of the atomic layers. At higher Λ values, the epitaxy is lost and polycrystalline MLs with strongly distorted atomic layers develop during deposition. In-situ high-temperature XRD demonstrated that Λ influences the phase evolution and kinetics during annealing. At annealing temperatures T A < 673 K Al diffuses into the Ru layers leading to the formation first of Ru(Al) solid solution. At T A > 823 K the ordered B2-RuAl phase is formed via a diffusion-controlled nucleation. The RuAl grain growth kinetics accelerates with increasing Λ.