Corrosion and Coatings

How is the corrosion current measured with the Tafel and LPR (Rp) methods?

Corrosion-current determination on an iron electrode in acid solution by Tafel extrapolation and polarisation resistance (Stern-Geary); EC-Lab® Tafel Fit and Rp Fit tools.

Sections of the note: Introduction · Experimental Conditions · Protocol Description · Stern Method (Tafel Fit) · Stern and Geary Method (Rp Fit) · Conclusion

How is rebar corrosion in reinforced concrete monitored electrochemically?

Rp and EIS measurement on steel in concrete, ohmic-drop correction due to the high resistance and long-term monitoring with the VMP3 (today VMP-3e).

Sections of the note: Introduction · Experimental Conditions · Results · Calculation of Polarization Resistance · Realkalization · CHARACTERIZATIONS OF THE METALLIC ROD.

How is pitting corrosion evaluated on multiple samples?

Pitting and repassivation potentials by cyclic polarisation; parallel sample testing with a multichannel instrument (VMP3/VSP → VMP-3e/VSP-3e).

Sections of the note: Introduction · Experimental Conditions · Results · LP Investigations · MPP Investigations and Statistics · Conclusion

How are Rp and the Tafel coefficients determined with the VASP technique?

Rp, βa and βc in a single measurement with variable-amplitude sinusoidal polarisation (VASP); application with the SP-300 and comparison with classical methods.

Sections of the note: Introduction · Experimental setup · Results · Conclusion

How is Rp determined with the CASP technique?

Calculation of corrosion parameters from the harmonics of constant-amplitude sinusoidal polarisation (CASP). (The source file was downloaded incorrectly; the summary will be completed when it is re-supplied.)

Electrochemical noise measurement 1: How is instrument noise validated according to ASTM?

Measurement of the instrument noise floor with a dummy cell under ASTM G199; noise performance of the SP-200/SP-300/VSP-300 and the ULC option.

Sections of the note: Introduction · ASTM Requirements · Experimental Setup · Results · Conclusion · Appendix

Electrochemical noise measurement 2: ASTM evaluation on a real system

Noise recording in ZRA mode in a real corrosion cell, data processing and ASTM evaluation of results obtained with the VSP-300.

Sections of the note: Introduction · ASTM Experiment · ASTM Comparison · Conclusion · Appendix

Electrochemical noise measurement 3: How is the noise resistance Rn calculated?

Rn determination from the standard deviations of potential and current noise, its relationship with Rp and use of the EC-Lab® ENA tool.

Sections of the note: Introduction · Experimental Conditions · Impedance Measurement · Noise Measurements · Results · Impedance Measurement

How is the corrosion current determined under mass-transfer-limited corrosion?

In oxygen-reduction-limited systems the Stern relation does not hold; the note gives the appropriate fit model in EC-Lab® and the interpretation of the results.

Sections of the note: Introduction · Corrosion with mass transfer limitation · I vs. E Relationship · Dummy cell · Stern method (Tafel fit) · Stern and Geary method

How much does ohmic drop mislead corrosion-current determination?

How uncorrected IR drop distorts Tafel slopes and Icorr; the effect of correction with ZIR with numerical examples.

Sections of the note: Introduction · Ohmic drop · Corrosion current measurement in presence of an ohmic drop · ZIR Technique · STERN Method (TAFEL Fit) · Stern and Geary method