scope:

This test method for making atmospheric corrosion measurements encompasses: 1) two-electrode electrochemical impedance, 2) zero resistance ammeter (ZRA), and 3) precision resistor current measurement techniques. The measurements can be used to quantify free corrosion, galvanic corrosion, conductance of surface contaminants (electrolyte layers), and properties of protective coatings. Factors important in specifying and selecting sensing elements and electrochemical measurement methods are provided. Sensing element types are described, along with excitation methods and data collection considerations. Methods are given to convert electrical responses to corrosion rate and cumulative corrosion measurements. Guidance is given for quality assurance practices, sensor preparation, and atmospheric corrosion testing. The test method also provides instruction for the preparation and testing of coatings using electrochemical sensors. Use and limitations of this method for determining the performance of materials and predicting corrosion behavior are described. Guidance is given for reporting sensor information, results, and environmental test parameters