Hi every body,
I added an inhibitor to the 1 M HCl solution and assessed the corrosion behavior of mild steel by electrochemical impedance spectroscopy.
Would you please tell me which EIS equivalent circuit shows a good fitting? please see the pics z1 ans z2.
How can I fit the observed "semi-inductor"part of the plot properly?
What is the reason for the observed inductor?
Many thanks in advance.
The pseudo-inductive characteristics, mainly in the (low) frequency (sub-Hz) response, are (hypothesized) to be due to many adsorbed intermediates on the WE, during the corrosion mechanism(s). An EC (equivalent circuit) set of models, to fit EIS with pseudo-inductive characteristics, is not easy task[1]; there are many unknown[2] experimental parameters in such a complex chemical system. These systems are dynamically modified hindering 1D, 2D, 3D-topology (as corrosion paths), sometimes following not, only, a single corrosion mechanism(s), as well as surface (and sub-surface) modifications[3]. So, we need specific[2] system prototype(s) in order to find a reliable EC model, to fit healthy (y)our EIS.
1. Corrosion inhibition of mild steel in 1M HCl ... https://www.nature.com/articles/srep44432
2. Aerated or Deaerated solution(?), the type(s) of mild steel(?), the surface preparation, depending on a rich set of the intermediates (on the WE), the temperature, ... etc.
3. The corrosion behaviour of a low carbon steel in ... https://www.saimm.co.za/Journal/v106n08p585.pdf.
The pseudo-inductive characteristics, mainly in the (low) frequency (sub-Hz) response, are (hypothesized) to be due to many adsorbed intermediates on the WE, during the corrosion mechanism(s). An EC (equivalent circuit) set of models, to fit EIS with pseudo-inductive characteristics, is not easy task[1]; there are many unknown[2] experimental parameters in such a complex chemical system. These systems are dynamically modified hindering 1D, 2D, 3D-topology (as corrosion paths), sometimes following not, only, a single corrosion mechanism(s), as well as surface (and sub-surface) modifications[3]. So, we need specific[2] system prototype(s) in order to find a reliable EC model, to fit healthy (y)our EIS.
1. Corrosion inhibition of mild steel in 1M HCl ... https://www.nature.com/articles/srep44432
2. Aerated or Deaerated solution(?), the type(s) of mild steel(?), the surface preparation, depending on a rich set of the intermediates (on the WE), the temperature, ... etc.
3. The corrosion behaviour of a low carbon steel in ... https://www.saimm.co.za/Journal/v106n08p585.pdf.
Dear Taher, look for this paper: Electrochimica Acta 121 (2014) 394. They got that inductance behavior during the corrosion of Mg. They used several equivalent circuits...
The lower frequency part of the spectrum might not be stationary yet. In other words, if the |Z| or R-value of the capacitive loop is decreasing with time, the low f region, where the inductive behavior was observed,
will be distorted, while the applied f increases during spectrum acquisition.
You can check that by increasing f just after the lowest applied f value and observe if the capacitive loop still has the same shape.
- Badges
- Science topic
- Similar topics
- Chemistry
- Electrochemistry