Background:
Lithium tantalate (LiTaO3) thin film was synthesized and in situ coated on
tantalum substrate via anodic oxidation.
Methods:
The effects of temperature, voltage and time on composition, morphology and hardness of
film were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers
hardness, respectively.
Results:
Our results showed that surface hardness of all coated samples has been increased compared
with that of pure tantalum. The value of hardness was found to gradually increase with temperature,
voltage and reaction time of the coating process. Selected specimens, after coating, were immersed
into 10 wt% NaOH solution at 50oC for 96h to explore their anti-corrosion performance. Immersing
results indicated that LiTaO3 coated samples have a smaller mass loss and corrosion rate compared
to those of pure Ta substrate. Pure tantalum sample and those coated by LiTaO3 thin film were further
examined by electrochemical methods including open-circuit potential (OCP), potentiodynamic
polarization curves and electrochemical impedance spectra (EIS).
Conclusion:
We have found that samples coated with LiTaO3 thin film exhibit higher potentials and
lower corrosion current densities than those of pure tantalum substrate, according to the results and
analysis of OCP curves and potentiodynamic polarization curves. Upon anodic oxidation, samples
display higher polarization resistance with higher resistance to corrosion.
Orientation and deformation conditions dependence of dislocation substructures in cold deformed pure tantalum
