Formation of self-organized niobium porous oxide on niobium

Abstract Anodization of niobium in mixed H 2 SO 4 /HF electrolytes was investigated. Under optimized electrochemical conditions the formation of self-organized porous Nb 2 O 5 layers was observed. The porous Nb 2 O 5 layers consist of ordered pore arrays with single pore diameters ranging from 20 to 30 nm. The pore morphology and the layer thickness strongly depend on the HF concentration and the time of anodization. Well-ordered uniform porous layers of up to 500 nm in thickness were formed. The formation of thicker layers is hampered by dissolution process and a tendency to film delamination.

[1]  B. Ohtani,et al.  Electrochromism of Niobium Oxide Thin Films Prepared by the Sol‐Gel Process , 1994 .

[2]  Kenji Fukuda,et al.  Ordered Metal Nanohole Arrays Made by a Two-Step Replication of Honeycomb Structures of Anodic Alumina , 1995, Science.

[3]  S. Maken,et al.  Kinetics of growth of anodic oxide film on niobium in aqueous electrolyte , 1988 .

[4]  Heon-Cheol Shin,et al.  Porous Tin Oxides Prepared Using an Anodic Oxidation Process , 2004 .

[5]  R. L. Aagard,et al.  Optical waveguide characteristics of reactive dc‐sputtered niobium pentoxide films , 1975 .

[6]  W. Badawy,et al.  Kinetics of the dissolution behaviour of anodic oxide films on niobium in NaOH solutions , 1987 .

[7]  N. Magnussen,et al.  Analysis of anodic oxide films on niobium , 1989 .

[8]  F. Kover,et al.  A comparative study of anodic oxide films on titanium, niobium and tantalum , 1968 .

[9]  G. Hutchings,et al.  Designing oxidation catalysts , 1999 .

[10]  C. D'Alkaine,et al.  The anodic behaviour of niobium—I. The state of the art , 1993 .

[11]  L. Young,et al.  An Ellipsometric Study of Steady‐State High Field Ionic Conduction in Anodic Oxide Films on Tantalum, Niobium, and Silicon , 1966 .

[12]  A. Mozalev,et al.  Nucleation and growth of the nanostructured anodic oxides on tantalum and niobium under the porous alumina film , 2003 .

[13]  Patrik Schmuki,et al.  Thick self-organized porous zirconium oxide formed in H2SO4/NH4F electrolytes , 2004 .

[14]  T. Oishi,et al.  Formation of Porous TiO 2 by Anodic Oxidation and Chemical Etching of Titanium , 2000 .

[15]  L. Young,et al.  Anodic Oxide Films , 1962 .

[16]  Craig A. Grimes,et al.  Titanium oxide nanotube arrays prepared by anodic oxidation , 2001 .