Corrosion Research and Corrosion Applied

Many corrosion phenomena are due to electrochemical reactions, therefore electrochemical techniques can be used to study these phenomena.  Measurements of current-potential relations under carefully controlled conditions yield information on corrosion rates, coatings and films, passivity, pitting tendencies, and other important data.  Techniques for applications such as rapid screening for materials selection, failure analysis, inhibitor evaluation, and even more specialized applications are widely known and practiced.  The National Association of Corrosion Engineers (NACE) and the American Society for Testing Materials (ASTM) have accepted several techniques as routine procedures, lending credibility and popularity to these electrochemical techniques. Techniques such as Tafel Plots, Polarization Resistance, Cyclic Polarization, Galvanic Corrosion, and Electrochemical Impedance Spectroscopy (EIS) are some of those common to corrosion studies.  We offer application notes for the non-electrochemist that describes not only the basic techniques, but also an overview of electrochemistry and its associated instrumentation as it pertains to corrosion measurements. 

Instrumentation for Electrochemical Corrosion Studies

Princeton Applied Research equipment has been used for electrochemical corrosion studies for over 25 years.  Starting with the Model 331-1 Corrosion Measurement System, Princeton Applied Research set the standards for corrosion testing equipment.  The Model 332 Corrosion Software, written originally in AppleSoft, was the first computer software written to run corrosion experiments with a potentiostat.  The Model 351 Corrosion System was the first use of a microprocessor in a corrosion measurement system.

From these beginnings, Princeton Applied Research has continued to provide the widest range of instrumentation for the study of corrosion phenomena.

Potentiostats and Galvanostats

All of the Princeton Applied Research computer controlled potentiostats (control DC potential and monitor resulting DC current) can also operate as galvanostats (control DC current and monitor the resulting DC voltage), and most of the available systems can be upgraded to perform AC techniques (EIS), as well.

For basic DC techniques, the Versastat 3 and 263A are excellent general-purpose systems.  When portability is an issue, the PARSTAT^®  2263 is lightweight, has a portable option for “floating” (isolated from ground) and working with grounded electrodes, and has an easy USB connection to a laptop or PC.  If working with larger electrodes where higher currents (>200mA) are in demand, both the Versastat 3 and 263A have 2 amp options. The model 273A, the most popular and most referenced potentiostats/galvanostat in the world, handles up to 1 amp of current.  The model PARSTAT 2273 is recommended when attempting to measure very low currents, such as those associated with titanium corrosion measurements.

For EIS studies (AC technique), the models 263A and 273A can be upgraded with additional hardware (i.e., 5210EC, or FRD100 frequency detectors)  to perform AC techniques.  For an all-in-one system, the Versastat 3 with FRA option is the system customers prefer most for performing both DC and AC techniques, and like the PARSTAT^®  2263 , has a portable option and an easy USB connection to a laptop or PC.

Software

For DC corrosion techniques with PARSTATs and GPIB-controlled systems, PowerCORR^®  offers 12 standard techniques, and has exceptional flexibility in customizing graphics and data handling.  For EIS techniques, PowerSINE^®  offers the same flexibility as PowerCORR^®, including the ability to place up to four different plots on the screen simultaneously (a powerful tool for ease of EIS data interpretation).  For equivalent circuit modeling of  EIS data, the software ZSimpWin is available to statistically compare acquired data with that of selected models.

Electrochemical Accessories

If you are going to perform corrosion studies, you will most likely need a cell for mounting your samples and containing the solution of interest.  Princeton Applied Research offers the K0047 Corrosion Cell (used in ASTM standard G-5 ) and the more flexible K0235 Flat Cell for studies on flat panels or specimens.  If your application is non-standard and you need the expertise of our highly experienced staff to offer suggestions, feel free to contact us with your application needs, and we will be glad to assist in any way that we can.

Imaging Techniques and Instrumentation

When it is desirable to obtain an image of the corrosion event occurring on the surface of the material, Princeton Applied Research offers several options for surface imaging.  The SVP370 uses the scanning reference electrode technique (SRET) to measure localized corrosion events of less than 5uA/cm^2 and to evaluate passivation/repassivation characteristics of a material.  The SKP370 conducts studies under atmospheric environments, and is ideal for semiconductor, filliform corrosion, and paint/coating applications.  Finally, there is the LEIS 370  which provides spatially resolved electrochemical impedance spectroscopy measurements for the surface study of coatings, corrosion inhibitors, localized corrosion, biofilms, delamination studies, and scratch tests.

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