Dear Vinith

As you know the kinetic of a chemical reaction of a metallic sample in a specific aqueous solution is time dependent. Therefore, by decreasing the scan rate , in a cyclic polarization test, in order to minimize the overall runtime of the test, you will probably lose some insight details of the obtained data in a comparison to the standard scan rate, as ASTM G5 standard.

Dear Vinith,

The selection of scan rate depends on the kinetic activity of the metallic samples in specific electrolytes. It can also be affected by the type of reaction (oxidation and/or reduction) of interest. It can not be selected same in all situations. Very active metals or catalytic surface can be scanned at high rate (larger than 10 mV/min) as you will always get limiting anodic or cathodic current response. The low scan rate will give you very noisy data in this case. Beyond certain limit at very high scan rates you will too start losing important information as suggested by Dr. Habib. In highly conductive electrolytes you will find less difference in polarization trends compared to the behavior in low conductivity solutions by varying scan rate within certain limits. I am not sure about your system in detail and therefore unable to give you specific conditions.

As a general rule, increase the scan rate gradually in three to four steps (different experiments under same conditions but different scan rates). If you see any significant shift in the curves (change in current at some specific potential or any shift in potential (Ecorr, etc.)), it means you must work at low scan rate or vice versa. Depending upon the system under study you may select the highest scan rate which have negligible influence on the curve shifting. Thanks

Kashif

Good Job

Thank you Sir for the kind compliment.