Influence of heat treatment on morphological changes of nano-structured titanium oxide formed by anodic oxidation of titanium in acidic fluoride solution.
TiO(2) nanotube array (TN) on titanium plate was fabricated by using an electrochemical method. The crystal structure and surface morphology of TN array was examined by X-ray diffraction (XRD) and Field Emission Scanning Electronic Microscopy (FE-SEM), respectively. The stability of the nanotube structure and crystal phase transition was studied at different temperatures in dry oxygen ambient. The as-deposited films were found to be amorphous. The tubes crystallized in the anatase phase at a temperature of 450 degrees C. Anatase crystallites formed inside the tubes walls was transformed completely to rutile at 500 degrees C in dry environment. With the heating temperature increased the intensity of rutile peak increased with decrease in reflection from titanium. Intense rutile peak was observed at 600 degrees C. The average pore diameter as calculated from FE-SEM images was 50-100 nm. At higher temperature tubular structure completely collapsed leaving dense rutile crystallites. A model was proposed to explain the formation mechanism of TN fabricated on titanium plate in HF/H(2)SO(4) electrolyte.
Neupane
Madhav Prasad
MP
Department of Bionanosystem Engineering, Chonbuk National University, Jeonju, Republic of Korea.
Park
Il Song
IS
Lee
Min Ho
MH
Bae
Tae Sung
TS
Watari
Fumio
F
D003460:Crystallization / Q000379:methods; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D006358:Hot Temperature; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010084:Oxidation-Reduction; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
D046911:Macromolecular Substances; C009495:titanium dioxide; D014025:Titanium