Common P-EIS[1] is non destructive[2], if you performed a measurement under the conditions:

1) a low Vac(:=1 to 5, mV) amplitudes,

2) a low over-potential stress Vdc(=OCP), and

3) short (stress) measurement time (

Hi,

EIS is nearly non destructive, if peformed with low amplitudes at the OCP. During Tafel meaurements you polarize cathodic/anodic for some hundred millivolts, which can seriously damage/alternate your specimen. Depends also on polarization speed.

Mass loss should be regarded to exposed area, then its no problem, when half of the sample is coated (not exposed). Take care to avoid crevice corrosion or degradation of the coating.

hope that helps, best regards

Andreas

hallo ,Dr.Jigness Hirpara , I have writing that might have something to do with the corrosion of your writing, try to examine how it might be understood?

EIS is non destructive at low frequencies and open circuit conditions. Taefel is destructive on the other hand and you cannot use the same sample for both

Common P-EIS[1] is non destructive[2], if you performed a measurement under the conditions:

1) a low Vac(:=1 to 5, mV) amplitudes,

2) a low over-potential stress Vdc(=OCP), and

3) short (stress) measurement time (

Dear Dr. Jignesh G. Hirpara,

as has already been said by several colleagues, the EIS technique is non-destructive while the petenziodynamic polarization tests used for the calculation of Icorr and Ecorr alter the situation of the sample (in particular the anodic branch). The material behaviour also depends on the aggressiveness of the solution in which the working electrode is immersed and on immersion time (before, during and after every test. Using the different techniques on a single sample must be successive; first EIS then the potentiodynamic polarizations and at times not too distant from each other. If you wanted to follow the progress of the different measurements over time, with the EIS technique you could use a single sample while for the potentiodynamic polarizations a dedicated sample would be necessary for each immersion time. If you are also interested in weight loss it is preferable to perform them on a series of samples at different immersion time and if your sample is painted it would be better to use a cell that exposes a well-defined area of ​​the uncoated sample to the corrosive solution. If these tests are carried out in a gravimetric way, remember also to check the cleaning procedures from any corrosion products formed on the exposed surface. Weight losses could also be achieved by using a chemical method such as soluble corrosion products present in the aggressive solution added to the insoluble corrosion products present on the surface of the exposed sample (after chemical dissolution of the same). The method is reliable but significantly more complex.

Best regards,

Pierluigi Traverso

Thank you very much for your valuable suggestions and information.

Welcome.

In my opinion, for corrosion study the main goal is to get reproducible and comparable results. This requires to start with well defined specimens surface conditions for each test. Therefore, I am not understand how the obtained results with multi techniques in serial will be discussed. Please do the tests systematically with separate specimens to be acceptable for all, then the results from EIS and Tafel scan be comparable and reproducible.

Best regards

You must perform the tests in the following order: EIS, stabilization of corrosion potential, Tafel. EIS is a non-destructive technique, so the surface of the sample will change as if it were exposed to the solution tested by the measurement time. The applied amplitude will depend on what metal (alloy) you are exploring.

G-EIS[1] mode is better[2,3] than the common P-EIS[1] mode as a non-destructive technique for very long time corrosion studies.

1. EIS: Potentiostatic or Galvanostatic Mode? https://www.gamry.com/application-notes/EIS/eis-potentiostatic-galvanostatic-mode/

2. STUDY OF CORROSION OF 13 Cr STAINLESS STEEL UNDER ALTERNATING CURRENT IN ARTIFICIAL SEAWATER https://mountainscholar.org/bitstream/handle/11124/170868/T6896.pdf?sequence=1&isAllowed=y

3. Answer of Jacinto Rosas, in: https://www.researchgate.net/post/differences_between_galvanostatic_and_potentiostatic_mode_in_electrochemistry_Why_is_the_galvanostatic_mode_more_stable