Potentiostat

Cormetrics has 3 high-sensitivity potentiostats for performing electrochemical measurements in our autoclave and RCE experiments. The potentiostat has a potential range of ±12V and maximum current of ±1 A. It is able to take current readings over 9 ranges with a minimum resolution of 3.3 fA. In combination with the attached multiplexer we can perform these measurements over multiple cells.

Depending on the test requirements, the following DC electrochemical methods can be used to monitor corrosion during the exposure period:

Linear Polarization Resistance (LPR)

Test design is to record current flow and material potentials between dissimilar metals and report on corrosion rate identifying the extent to which one material is anodic to the other. Weight loss corrosion rate are also recorded. The standard experiment is completed over a four day period in the pressurized autoclaves or over a two day period at atmospheric pressure in the rotating cylinder electrode apparatus.

Cyclic Potentiodynamic Polarization (CPP)

Test design is to investigate the pitting and repassivation of materials. Also used to indicate inhibitor influence on pitting potentials. Standard test is run in the autoclaves over a two day period. Reporting includes discussion on the open circuit, pitting and repassivation potentials.

Zero Resistance Ammeter (ZRA)

Potentiostatic Polarization

Test design is to apply a small potential to the electrode and determine the current response. This technique is used to evaluate materials and can be informative for corrosion inhibitor testing. The technique is combined with the CPP scan to determine the applied potential for the test and is typically run over a three day period.