Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1664426 | Thin Solid Films | 2016 | 11 Pages |
Abstract
The electrochemical behavior of titanium has been investigated in chloride electrolyte of different pH values (2.1, 5.2 and 7.4). Potentiodynamic polarization studies showed wide passive behavior irrespective of change in pH. Passive films were grown by applying different passive potentials (0.2 to 0.6 V (vs SCE)) by recording chronoamperometric curves for duration of 8 h. Electrochemical impedance spectroscopy (EIS) measurements showed higher impedance values for the oxide layer grown in neutral pH condition and for oxides formed at higher formation potentials. Emphasis is made mainly on the properties of titanium oxide estimated by Mott-Schottky analysis, which shows that passive film formed, is of n-type semiconducting film and the donor concentration is in the order of 1020 cmâ 3. The calculated diffusivity of point defects is in the range of (0.5 to 2.5) à 10Ë16 cm2sâ 1 and tends to decrease with increase in electrolyte pH. Surface morphology of the passive films was examined using scanning electron microscope and surface roughness was characterized using confocal microscope. Ex- situ ellipsometry measurements were performed to analyze the optical constants of the oxide layer and to determine the oxide thickness. The thickness is in the range of 3.5 to 5.8 nm and comparable to the calculated values.
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Balakrishnan Munirathinam, R. Narayanan, Lakshman Neelakantan,