Metals and Materials International

, Volume 22, Issue 2, pp 305–310

Nanoporous microtubes obtained from a Cu-Ni metallic wire

  • Emanuele Francesco Marano
  • Danilo Lussana
  • Alberto Castellero
  • Marcello Baricco
Article

Abstract

Nanoporous microtubes of a nickel-copper alloy were obtained from a Cu-44Ni-1Mn (wt%) commercial wire (200 μm diameter). A new synthesis method was established through three steps: 1) partial oxidation of the wire at 1173 K in air, 2) removal of the inner unoxidized core by chemical etching, 3) reduction in 10 bar hydrogen atmosphere. During oxidation, the segregation of Cu and Ni occurred because of their different diffusion coefficients in the corresponding oxides. As a consequence, pores were formed by Kirkendall effect and due to selective chemical etching of the different oxides. Additional porosity formed because of volume contraction during reduction with hydrogen. After reduction, the microtube shows a composition gradient from the inner wall (almost pure nickel) to the outer wall (almost pure copper). The process allowed to obtain microtubes with tuneable wall thickness and inner pores around 180 ± 80 nm. The morphological features developed suggest improved capillarity properties for applications in MEMS.

Keywords

microtube porous materials annealing oxidation X-ray diffraction 

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Copyright information

© The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  • Emanuele Francesco Marano
    • 1
  • Danilo Lussana
    • 2
  • Alberto Castellero
    • 1
  • Marcello Baricco
    • 1
  1. 1.Department of Chemistry and NISUniversity of TurinTurinItaly
  2. 2.Cogne Acciai Speciali SpaAostaItaly

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