Tuesday, March 28, 2017
This presentation will focus on the new standard test method for the specification, selection, and use of sensors for monitoring atmospheric corrosion that are based on electrochemical techniques. The sensors may be used like more traditional mass loss coupons or painted test panels, but these sensors provide continuous records of contaminants, corrosion rates, or coating condition over time as opposed to singular cumulative measurements of mass loss or coating degradation. This method permits instantaneous evaluation of corrosion rates so that situations where changes in environmental conditions cause changes in the corrosion rate can be detected in real time. This is considered a substantive benefit as compared with mass loss methods. These continuous records of material condition are broadly applicable to studying atmospheric corrosion, evaluating materials, or managing assets.
The method addresses the use of electrochemical sensors in a bare metal condition or with protective coatings. It encompasses sensor elements for measurement of free corrosion, galvanic corrosion, and conductance for assessing atmospheric corrosion. Atmospheric corrosivity measurements, using electrochemical based sensors, provide a means to obtain instantaneous corrosion rate, surface contaminant, and coating property estimates over long exposure periods. The electrochemical-based sensors may be used to estimate free corrosion rate of specific alloys, galvanic corrosion rate of coupled materials, conductance of surface moisture layers, or the barrier properties of coatings. These sensors may be included in instrumentation used in accelerated test chambers, outdoor exposure sites, or actual service environments.
Two presentations are related to the draft standard TG530 with time for discussion of the intended uses and recent results with sensors covered by the draft standard.
Presented by: Fritz Friefersdorf, Luna Innovations and James Dante, Southwest Research Institute