I am running corrosion tests on a Verastat3 potentiostat. I am getting decent curves, but when I look at the displayed value, my beta vales for the cathode and the anode are the same. Is this possible?
Unlikely but not impossible. Question though: are those measured beta values from a Tafel curve or are they values that are input? Default inputs for beta constants are commonly 120 mV/decade as that minimizes the maximum error.
Unlikely that they are absolutely the same. If so, that are maybe given values or from a (wrong) matematical algorithm. How about deriving beta values by yourself from anodic/cathodic branches?
Jacob Ketter
Jacob, they are calculated when I move the slopes during the Curve Analysis after the Tafel curves are formed. I can move the slopes to the curves and adjust to make the best slope where the curve goes up (anode) and down (cathode).
Michael Bram Kuijer, in that case, it's probably just that the actual constants are close enough that the fitting algorithm lands on the same values. I can't discount that there could be a problem, however--if the slopes look very different then there is some problem but I can't say what because I'm not sufficiently familiar with the software.
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