linear polarisation resistance measurementReading time:
This electrochemical type measurement is used for continuous monitoring of corrosion. After a few days’ exposure, measurements are carried out electrically without removing the test piece from the corrosive fluid and, therefore, without disturbing the system. Therefore, this type of measurement is perfectly suited to crisis situations where the reasons for excessive corrosion have to be found quickly.
The principle behind this method consists in applying a low voltage (10-20 mV) to the electrodes and in measuring the resulting current: the current’s intensity will be linked to the rate of corrosion (the LPR assumes that the water in the circuit has minimum electrical conductivity, typically 100 mS · m–1 and more).