Surface microstructures and corrosion resistance of Ni-Ti-Nb shape memory thin films

  • Kun Li
  • , Yan Li*
  • , Xu Huang
  • , Des Gibson
  • , Yang Zheng
  • , Jiao Liu
  • , Lu Sun
  • , Yong Qing Fu
  • *Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Ni-Ti-Nb and Ni-Ti shape memory thin films were sputter-deposited onto silicon substrates and annealed at 600 °C for crystallization. X-ray diffraction (XRD) measurements indicated that all of the annealed Ni-Ti-Nb films were composed of crystalline Ni-Ti (Nb) and Nb-rich grains. X-ray photoelectron spectroscopy (XPS) tests showed that the surfaces of Ni-Ti-Nb films were covered with Ti oxides, NiO and Nb 2 O 5 . The corrosion resistance of the Ni-Ti-Nb films in 3.5 wt.% NaCl solution was investigated using electrochemical tests such as open-circuit potential (OCP) and potentio-dynamic polarization tests. Ni-Ti-Nb films showed higher OCPs, higher corrosion potentials (E corr ) and lower corrosion current densities (i corr ) than the binary Ni-Ti film, which indicated a better corrosion resistance. The reason may be that Nb additions modified the passive layer on the film surface. The OCPs of Ni-Ti-Nb films increased with further Nb additions, whereas no apparent difference of E corr and i corr was found among the Ni-Ti-Nb films.

Original languageEnglish
Pages (from-to)63-67
Number of pages5
JournalApplied Surface Science
Volume414
DOIs
StatePublished - 31 Aug 2017

Keywords

  • Corrosion resistance
  • Microstructures
  • Ni-Ti-Nb
  • Thin film

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