Formation of barrier-type amorphous anodic films on Ti-Mo alloys

H. Habazaki, M. Uozumi, H. Konno, S. Nagata, K. Shimizu

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

Barrier-type amorphous anodic films with uniform thickness grow at high current efficiency on sputter-deposited Ti-Mo alloys containing 11.5-37.0 at.% molybdenum to high voltages of more than 100 V in 0.1 mol dm-3 ammonium pentaborate electrolyte, in contrast to an amorphous-to-crystalline transition of anodic film on titanium and subsequent oxygen formation at relatively low voltages of less than 20 V. During anodizing of the alloys at a constant voltage of 80 V, the currents decrease to the order of 10-2 A m-2 within 3 h, whereas the current for titanium decreases only to the order of 1 A m-2, due to the presence of flaws in the film, associated with oxygen evolution. The capacitance of the anodic films formed on the Ti-11.5 at.% Mo alloy is almost comparable to that formed on tantalum at the same voltage. The increase in molybdenum content in the alloy results in a slight decrease in the capacitance of the films. From these results, the structure of anodic films on titanium can be modified by incorporation of molybdenum species from the substrate so that uniform amorphous anodic films with a relatively high capacitance and a low defect density have been obtained.

Original languageEnglish
Pages (from-to)151-154
Number of pages4
JournalSurface and Coatings Technology
Volume169-170
DOIs
Publication statusPublished - 2003 Jun 2

Keywords

  • Amorphous oxide
  • Anodizing
  • Capacitance
  • TEM
  • Ti-Mo alloy

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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