Aluminium–copper–nickel thin film compositional spread: Nickel influence on fundamental alloy properties and chemical stability of copper

• Published in: Thin solid films 2015-04, Vol.580, p.36-44
• Main Authors: Hafner, Martina, Burgstaller, Wolfgang, Mardare, Andrei Ionut, Hassel, Achim Walter
• Format: Article
• Language: English
• Subjects: Aluminium–copper alloys; Aluminum; Auger electron spectroscopy; Co-evaporation; Copper; Corrosion; Corrosion resistance; Cyclic voltammetry; Dissolution; Downstream analytics; Nickel; Scanning droplet cell microscopy; Scanning Kelvin probe; Thin film combinatorial libraries; Thin films; Voltammetry
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2015.03.018

An Al–Cu–Ni thin film compositional spread was deposited by thermal evaporation and investigated in order to study the Ni influence on the overall properties. The chemical composition was detected by energy dispersive X-ray spectroscopy and showed a compositional spread of approximately 20at.% Ni. Decreasing the Ni content in the Al–Cu–Ni thin films resulted in an increased grain size and characteristic surface microstructure evolution. Scanning Kelvin probe measurements were performed to investigate the surface potential variation along the compositional gradient, and a distinct surface potential drop was observed between Al–Cu–7at.% Ni and Al–Cu–13at.% Ni. The results of the X-ray photoelectron spectroscopy surface analysis and Auger electron spectroscopy as well as the electrochemical investigations by cyclic voltammetry evidenced mainly the presence of Al2O3 but also CuO and Cu2O together with metallic Cu were clearly identified along the compositional gradient. Chemical dissolution experiments have shown that Ni is enhancing the chemical stability of Cu, excepting inside the compositional region between 7 and 13at.% Ni. •Properties of Al–Cu–Ni thin film combinatorial library (5–25at.% Ni) were mapped.•A surface potential drop was found between AlCu–7at.% Ni and AlCu–13at.% Ni.•CuO, Cu2O and Cu were found along the Al–Cu–Ni library by cyclic voltammetry.•Downstream analytics probed the corrosion behaviour of Al–Cu–Ni alloys.•Ni enhanced Cu chemical stability excepting the compositional range 7–13at.% Ni.