MEASUREMENT AND PREVENTION OF CORROSION BY ELECTROCHEMICAL METHODS

Abstract

THE ELECTROCHEMICAL THEORY OF AQUEOUS CORROSION IS BRIEFLY REVIEWED, AND THE APPLICATIONS AND LIMITATIONS OF LABORATORY ELECTROCHEMICAL TECHNIQUES ARE DESCRIBED. EXAMPLES OF ALLOY EVALUATION BY ANODIC POLARIZATION ARE DISCUSSED, PARTICULARLY IN ENVIRONMENTS SIMULATING INDUSTRIAL SERVICE CONDITIONS. APPLICATIONS AND LIMITATIONS OF ANODIC PROTECTION ARE OUTLINED TOGETHER WITH REFERENCES TO THE ENGINEERING OF ANODIC PROTECTION SYSTEMS. CATHODIC PROTECTION IS DISCUSSED WITH RESPECT TO THE APPLIED CURRENT AND ELECTROCHEMICAL POTENTIAL REQUIRED FOR ADEQUATE PROTECTION, CONTROLLED POTENTIAL CATHODIC PROTECTION, AND THE PERFORMANCE OF SACRIFICIAL ANODES. ELECTROCHEMICAL CORROSION RATE DETERMINATIONS ARE REVIEWED. THE POLARIZATION RESISTANCE (OR LINEAR POLARIZATION) METHOD IS DESCRIBED AS A USEFUL TECHNIQUE TO MONITOR CHANGES IN CORROSIVITY OF CERTAIN INDUSTRIAL PROCESS STREAMS. IN GENERAL, THE DISCUSSIONS ARE LIMITED TO THOSE ASPECTS OF THEORY AND PRACTICE WHICH MAY BE OF INTEREST TO THE PRACTICING ENGINEER CONCERNED WITH SERVICE CORROSION PROBLEMS AND MATERIALS SELECTION. /AUTHOR/