13.7 Anodization of Valve Metals
499
Table 13.3 Valve metals
yielding a porous
nanostructure upon
anodization with a few
representative reference
studies
Anodized valve metal
References
Zr
[203–208]
Nb
[209–212]
Hf
[213–216]
Ta
[217–221]
W
[222–227]
(iv) The oxide structure formed is either amorphous or crystalline and the degree
of crystallinity can be improved with annealing up to the collapse temperature of
the nanostructure. A few examples for works dealing with this field are summarized in Table 13.3, and the transition between nanoporous to nanotubular oxide is
exemplified for Zr in Fig. 13.6.
Fig. 13.6 Transition from a porous to nanotubular structure of anodized zirconium with the change
of the water content of NH 4 F solution in glycerol. Insets show the cross-sectional morphology.
Reprinted from [204]. Copyright (2008), with permission from Elsevier
499
Table 13.3 Valve metals
yielding a porous
nanostructure upon
anodization with a few
representative reference
studies
Anodized valve metal
References
Zr
[203–208]
Nb
[209–212]
Hf
[213–216]
Ta
[217–221]
W
[222–227]
(iv) The oxide structure formed is either amorphous or crystalline and the degree
of crystallinity can be improved with annealing up to the collapse temperature of
the nanostructure. A few examples for works dealing with this field are summarized in Table 13.3, and the transition between nanoporous to nanotubular oxide is
exemplified for Zr in Fig. 13.6.
Fig. 13.6 Transition from a porous to nanotubular structure of anodized zirconium with the change
of the water content of NH 4 F solution in glycerol. Insets show the cross-sectional morphology.
Reprinted from [204]. Copyright (2008), with permission from Elsevier