Electrochemical Behavior of Tantalum in Anhydrous Ethanol

The electrochemical behaviors of Ta in Et 4 NCl ethanol solutions were investigated using potentiodynamic polarization, cyclic voltammetry, and potentiostatic current-time transient techniques, complemented with a scanning electron microscope (SEM). The potentiodynamic anodic polarization curves did not exhibit an active dissolution region due to the presence of a thin oxide film on the electrode surface, which was followed by pitting corrosion as a result of passivity breakdown by the aggressive attack of Cl - anions. SEM images confirmed the existence of pits on the electrode surface. The pitting potential (E b ) decreased with the increase in solution temperature, but increased with increasing potential scan rate. The potentiostatic current-time transients showed that the incubation time slightly decreased with increasing Et 4 NCl concentrations. The pitting growth current density agreed well with Hills's model.

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