Microstructure and Electron Energy-Loss Spectroscopy Analysis of Interface Between Cu Substrate and Al2O3 Film Formed by Aerosol Deposition Method

• Published in: Journal of thermal spray technology 2014-12, Vol.23 (8), p.1333-1338
• Main Authors: Naoe, Kazuaki, Nishiki, Masashi, Sato, Keishi
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Exact sciences and technology; Machines; Manufacturing; Materials Science; Metals. Metallurgy; Peer Reviewed; Processes; Production techniques; Surface treatment; Surfaces and Interfaces; Thin Films; Tribology
• ISSN: 1059-9630; 1544-1016
• DOI: 10.1007/s11666-014-0172-4

Aerosol deposition method is a technique to form dense films by impacting solid particles on a substrate at room temperature. To clarify the bonding mechanism between AD films and substrates, TEM observation and electron energy-loss spectroscopy (EELS) analysis of the interface between Al 2 O 3 AD films and Cu substrates were conducted. The Al 2 O 3 film was directly adhered to the Cu substrate without any void or crack. The film was composed of randomly oriented α-Al 2 O 3 crystal grains of about 10-20 nm large. At the Al 2 O 3 /Cu interface, the lattice fringes of the film were recognized, and no interfacial layer with nanometer-order thickness could be found. EELS spectra near O- K edge obtained at the interface had the pre-peak feature at around 528 eV. According to previously reported experiments and theoretical calculations, this suggests interactions between Cu and O in Al 2 O 3 at the interface. It is inferred that not only the anchoring effect but also the ionic bonding and covalent bonding that originates from the Cu-O interactions contribute to the bonding between Al 2 O 3 AD films and Cu substrates.