Is it possible to use a devanathan cell to measure hydrogen diffusion during corrosion this way :
The entry side (also called cathode side), corrosion of the working electrode generates hydrogen that enters the working electrode (no power supply or potentiostat etc., only corrosion in humid condition).
The exit side (also called anodic side), here we have a counter electrode and a reference electrode that measures the current from the oxidized hydrogen (generated by the corrosion) that has diffused through the working electrode.
So is this possible, or will the corrosion reaction (Fe-->Fe2+ + 2e-) on the entry side disturb the measurement on the exit side (H-->H+ + e-)?
Hi Kristina, I see no problem why it should not work that way. Consider that you will only detect H from corrosion on the entry side, when its formed there, adsorbed, absorbed and diffuse through the metal to the detection side. Maybe you want use the technique to study H-entry during ewtmospheric corrosion? Then this paper could be of interest for you: doi:10.1016/j.electacta.2010.09.043
I just dont get how the potentiostat can distinguish between the current from the hydrogen oxidation and the current from the iron oxidation. Or do one assume that the current from the iron oxidation will be consumed by the cathodic counter reaction? I mean all this is going on on the working electrode. I guess Im missing something relevant as nobody ales think this is a problem. I want to understand...
as far as I know you need 2 potentiostats, one for H-detection and one for loading or corrosion ;-)
p.s. if you mean the detection side, you work with alkalic solution and assume passivity of the electrode, therefore no significant corrosion should take place and you are able to measure purely H-oxidation (+ some passive currents that maintain passivity)
I mean that you just corrode the sample (working electrode) in a corrosive atmosphere on the entry side (no potentiostat or power supply connected) and on the exit side you have a CE and reference electrode and detect the current from the oxidized hydrogen.
So is this possible, or will the corrosion reaction (Fe-->Fe2+ + 2e-) on the entry side disturb the measurement on the exit side (H-->H+ + e-)? Both reactions gives electrons to the working electrode.
Or do I know that on the entry side, the electrons from (Fe-->Fe2+ + 2e-)will be consumed by the counter cathode reaction on the entry side?
Hi Kristina,
since you have a separate electrolyte on the detection side of your sample, you will not see any of the corrosion reactions there, just the diffusing/effusing H on the detection side, if there´s any from corrosion reactions. Hope that helps ;-)
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