electrochemical corrosion testing

Menu:

Electrochemical Corrosion Tests:

Electrochemical corrosion tests rely on electrochemical theory and electrochemical corrosion measurements to characterize corrosion damage and, where possible, estimate corrosion rates. Fundamentally, two types of electrochemical measurements can be made:

Applying external current to generate electrochemical data away from the free corrosion potential. These tests generally explore the relationship between electrochemical potential and current.
Electrochemical measurements at the free corrosion potential, without the application of an external current.

The usefulness of electrochemical corrosion tests for short term, accelerated testing is based on the following fundamental considerations:

The application of external current allows corrosion damage, such as pitting corrosion, to be induced and studied in very short time frames (typically within minutes).
Electrochemical corrosion rate measurements can be made almost instantly, long before a conventional weight change would be measurable.

References/Literature:

ASTM G5: Standard Reference Test Method for Making Potentiostatic and Potentiodynamic Anodic Polarization Measurements.

ASTM G59: Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements.

ASTM G61: Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements for Localized Corrosion Susceptibility of Iron-, Nickel-, or Cobalt-Based Alloys.

ASTM G102: Standard Practice for Calculation of Corrosion Rates and Related Information from Electrochemical Measurements.

ASTM G106: Standard Practice for Verification of Algorithm and Equipment for Electrochemical Impedance Measurements.

Links:

More on classification of "dc" and "ac" techniques.

ASTM International
www.astm.org