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MONITORING AND MEASUREMENT TECHNIQUES - Coggle Diagram
MONITORING AND MEASUREMENT TECHNIQUES
Weight Loss measurement
The method involves exposing a specimen of material (the coupon) to a process environment for a given duration, then removing the specimen for analysis
The basic measurement which is determined from corrosion coupons is weight loss; the weight loss taking place over the period of exposure being expressed as corrosion rate
Advantages of weight loss coupons
Inhibitor performance can be easily assessed
Visual inspection can be undertaken
The technique is applicable to all environments - gases, liquids, solids/particulate flow
Localized corrosion can be identified and measured
Corrosion deposits can be observed and analyzed
Potentiodynamic Polarization Measurements
Enables the electrochemist to determine information relating to the corrosion rate, passivity and pitting susceptibility
Potentiodynamic polarization is the characterization of a metal specimen by its current - potential relationship
A potentiodynamic anodic polarization plot can yield important information
The ability of the material to spontaneously passivate in the particular medium
The potential region over which the specimen remains passive
The corrosion rate in the passive region
Linear Polarization resistance
Useful for determining the effect on the corrosion rate of a number of possible corrosion inhibitors added at different concentrations
Electrochemical Impedance Spectroscopy(EIS)
The terms resistance and impedance both denote an opposition to the flow of electrons or current
In direct current (DC) circuits, only resistors produce this effect. However, in alternation current (AC) circuits, two other circuit elements, capacitors and inductors, impede the flow of electrons
Electrochemical impedance is usually measured by applying an AC potential to an electrochemical cell and measuring the current through the cell
A resistor is the only element that impedes the flow of electrons in a DC circuit.