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Wednesday, March 19, 2008 - 2:20 PM
Convention Center, Second Level, R05 (Ernest N. Morial Convention Center)
08389
Microelectrochemical Techniques for Characterization of the Behavior of Corrosion Resistant Alloys (CRA)
The standard way to perform electrochemical measurements on metallic specimen is to cut pieces from the part under consideration, connect it to an electrical lead and immerse it into a vessel type electrochemical cell. This means that the part has to be destroyed and the specimen is exposed with all sides to the electrolyte. In quality control and field evaluations there are many situations where a destruction is not possible. In other cases only specific surface areas of a samples should be evaluated. In both these cases special electrochemical cells are to be used. In very special cases the sensitivity of the measurements can be increased when the size of the measuring spot is reduced to diameters well below 1 mm. With these cells very small areas of sensitized zones in austenitic and martensitic stainless steels can be detected. In other cases the techniques are used to characterize the surface properties of austenitic and duplex stainless steels. The electrochemical techniques used with the microcells include classical DC techniques as well as EPR-tests, electrochemical impedance measurments and electrochmical noise analysis. The chances and the limits of the techniques are shown.