The electrochemical technique, commonly referred to as Linear Polarization Resistance, is the only corrosion monitoring method that allows corrosion rates to be measured directly, in real time. Although limited to electrolytically conducting liquids, the response time and data quality of this technique make it clearly superior, where applicable, to all other forms of corrosion monitoring.
Polarization resistance is particularly useful as a method to rapidly identify corrosion upsets and initiate remedial action, thereby prolonging plant life and minimizing unscheduled downtime. The technique is utilized to maximum effect, when installed as a continuous monitoring system.
This technique has been used successfully for over thirty years, in almost all types of water-based, corrosive environments. Some of the more common applications are:
- Cooling water systems
- Secondary recovery system
- Potable water treatment and distribution systems
- Amine sweetening
- Waste water treatment systems
- Pickling and mineral extraction processes
- Pulp and paper manufacturing
- Hydrocarbon production with free water
When a metal/alloy electrode is immersed in an electrolytically conducting liquid of sufficient oxidizing power, it will corrode by an electrochemical mechanism. This process involves two, simultaneous, complementary reactions.
At anodic sites, metal will pass from the solid surface into the adjacent solution and, in so doing, leave a surplus of electrons at the metal surface. The excess electrons will flow to nearby sites, designated cathodic sites, at which they will be consumed by oxidizing species from the corrosive liquid.
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