Electrochemical Corrosion

Electrochemical Corrosion Research
Researchers looking at high throughput or materials selection are looking for easy-to-use, reliable systems, that give them the right answer. Gamry has long been known as the market leader when it comes to instrumentation for electrochemical corrosion testing.

 

Gamry Advantages

Researchers looking at high throughput or materials selection are looking for easy-to-use, reliable systems, that give them the right answer.  Gamry has long been known as the market leader when it comes to instrumentation for corrosion testing.  Running ASTM testing is easy with our standard list of experiments – Polarization Resistance, Potentiodynamic, Cyclic Polarization, etc.  Our Sequence Wizard lets you string together experiments, click Start, and then come back when finished.

All of Gamry potentiostats are electrically isolated, allowing you to run experiments on grounded cells such as autoclaves.  High compliance voltages ensure adequate power when dealing with resistive electrolytes. 

Our analysis software allows for easy data workup, reporting and charting.  Easily compare results or export data for workup in another program.

Gamry Expertise

Gamry Instruments has been producing lower cost, electrically isolated potentiostats for corrosion testing since 1989. We have the most comprehensive electrochemical corrosion technique library around, including Gamry developed/exclusive experiments.

We are also very willing to share our expertise with our customers. There are Applications Notes which are relevant to corrosion scientists and engineers. We also have electrochemistry specialists available over email or phone that understand corrosion testing, and can get you pointed in the right direction.

If you are new to corrosion research and electrochemical corrosion testing in particular, you may want to start with a quick look at our Application Note on DC Corrosion Techniques, and consider enrolling in a short course like the one taught at Pennsylvania State University every summer. For those who are already familiar with the electrochemical corrosion process, please have a look at our Application Notes covering Electrochemical Impedance Spectroscopy, and consider swapping your Rp/Ec Trend out with EFM Trend.

Recommended

Recommended Systems:

Routine ASTM G 59, G 61, F 746, or F 2129 Testing - Interface 1010B1010E or 5000E (single or multichannel setups depending on throughput needs), Multiport, two Saturated Calomel Reference electrodes (one as a backup).  Gamry recommends the ECM8 Electrochemical Multiplexer if increased throughput at a lower price point is necessary. Note that the multiplexer runs experiments sequentially, not simultaneously. For very corrosion resistant systems (very low corrosion rates), Gamry recommends the Reference 600+ due to its low-current (60 pA lowest full-scale range) capabilities. 

If you are considering doing electrochemical impedance experiments, the Interface 1010E, Reference 600+, Reference 3000, and Reference 3000AE are all ideal instruments.  

Critical Pitting Temperature - Any of the above-mentioned instruments can perform critical pitting temperature experiments but you will also need a TDC4 temperature controller (or equivalent), FlexCell, heating mantle, stirring motor, and stirring rod kit.  

Electrochemical Corrosion Q & A

What is electrochemical corrosion?

Most metallic corrosion occurs via electrochemical reactions at the interface between the metal and an electrolyte solution.   

Corrosion is a chemical process whereby materials deteriorate as part of the oxidation process. Corrosion typically occurs when a metal is under stress or is in an anaerobic, or airless, environment. Metal ions dissolve and are taken up by a depolarizer, typically Oxygen.  

Why is corrosion an electrochemical process?

Corrosion is an electrochemical process because it is the process where electrons move from one area of a metal surface to another through an environment hospitable to ions. Liquid, in some form, typically acts as an electrolyte that reacts chemically with the metal surfaces.  

Corrosion normally occurs at a rate determined by an equilibrium between opposing electrochemical reactions. The slowest chemical reaction between ions controls how fast corrosion occurs. It happens because of metals tendency to return to its naturally occurring state, as an oxide or ore.  

One reaction is the anodic reaction, in which a metal is oxidized, releasing electrons into the metal.  

What is the difference between chemical and electrochemical corrosion?

Chemical corrosion occurs in wet conditions such as the presence of electrolyte or moisture. Electrochemical corrosion takes place by an electrochemical attack of corrosive environment on the surface of metal. Electrochemical corrosion is typically faster than chemical corrosion. It is typically more common and more severe.   

What four things are necessary for electrochemical corrosion to occur?

The four things needed for electrochemical corrosion are: anode, cathode, electrolyte, and a return current path.  

Anodic and Cathodic reactions

Anode - The electrode where galvanic reactions generate electrons.  Negative ions are discharged - positive ions are formed. Corrosion occurs at the anode.  

Cathode - The electrode that receives electrons - positive ions are discharged, negative ions are formed. The cathode is protected from corrosion.  

Most metallic corrosion occurs via electrochemical reactions at the interface between the metal and an electrolyte solution.

Electrolyte - The conductor through which current is carried. Electrolytes include aqueous solutions or other liquids.  

The potential of the metal is the means by which the anodic and cathodic reactions are kept in balance.

Return Current Path - The metallic pathway connecting the anode to the cathode. It is often the underlying metal substrate.

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