الفهرس 
ExperimentalOnly 14 pages are availabe for public view
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Abstract
Zinc (Zn) metal and its oxide (ZnO) are recognized as being extensively used engineering materials for widespread applications in many industries. Therefore, the electrochemical and semiconductor properties of spontaneously formed and electrodeposited passive films on pure zinc metal were carefully investigated to gain more information about their behaviors in alkaline carbonate/bicarbonate buffer mixtures.The effect of different operating parameters such as: solution pH, temperature, immersion time and formation voltage (Va), in addition to the dopant (nature and its concentration) were examined and discussed.
The study was performed using different electrochemical measurements, Mott-Schottky analysis and surface characterization techniques. Undoped and doped electrodeposited thin oxide films on zinc metal were formed potentiostatically at -1.04 to -0.99 V (vs. Ag/AgCl), while the choronoamperometric traces were recorded during the deposition method. The processing solution was pH 9.2 borate buffer solution free or containing the dopant Li+ or In3+ ions.
The results revealed direct correlation between each of buffer pH, temperature, immersion time and Va with the total film resistance (Rf) and its thickness (δf). Generally, zinc passivation is enhanced with increasing pH over the range 9.2 to 9.8, decreasing the ambient temperature, increasing immersion time or the formformation voltage (Va), in parallel with the increase of its film thickness. In the meantime, (Rf) values for the undoped anodic ZnO films are always higher than those for the doped ones.
Mott-Schottky results showed that the charge carrier donor concentration (ND) increases by increasing either pH, Va or In3+ doping level, but it decreases by increasing the solution temperature or Li+ dopant concentration, commensurate with the increasing or decreasing trends, respectively in the thickness of the formed oxide film.