INSIGHT INTO Corrosion

The well-known Pourbaix diagrams (showing specific zones in which no corrosion and passivation occur), in which pH is plotted against electrode potential, are valid only in pure water at 25°C. A comparison of the behavior of zinc and other metals offers a deeper insight into corrosion by water, however. 

While supercritical water oxidation (SCWO) chemistry conditions are much more aggressive than those expected in an SCWR core, there is some synergy between these systems and SCWO data can provide insights into corrosion phenomena in an SCWR core [11]. 

The mechanisms of lead corrosion in sulfuric acid have been studied and good reviews of the Hterature are available (27—30). The main techniques used in lead corrosion studies have been electrochemical measurements, x-ray diffraction, and electron microscopy. More recendy, laser Raman spectroscopy and photoelectrochemistry have been used to gain new insight into the corrosion process (30,31). 

Other Useful Information Obtained by Probes Both EIS and electrochemical noise probes can be used to determine information about the reactions that affect corrosion. Equivalent circuit analysis, when properly applied by an experienced engineer, can often give insight into the specifics of the corrosion reactions. Information such as corrosion product layer buildup, or inhibitor effectiveness, or coating breakdown can be obtained directly from analysis of the data from EIS or indirectly from electrochemical noise data. In most cases, this is merely making use of methodology developed in the corrosion laboratory. 

Reardon, P. A. Bernahl, W.E. New Insights into Oxygen Corrosion Control. Nalco/NACE International Corrosion Forum, 87. NACE International, USA, March 1987. 

Corrosion is the unwanted oxidation of a metal. It cuts short the lifetimes of steel products such as bridges and automobiles, and replacing corroded metal parts costs billions of dollars a year. Corrosion is an electrochemical process, and the electrochemical series is a source of insight into why corrosion occurs and how to prevent it. 

Some data from corrosion-monitoring probes do not measure corrosion rate, but rather give other useful information about the system. For example, suppose conditions change dramatically during a process upset. An ejq)erienced corrosion engineer can examine the data and correlate it with the upset conditions. Such analysis can provide insight into the process and help to improve performance and extend equipment lifetime. Changes in simple parameters such as pH, ion content, and temperature may lead to detection of a process upset. Without careful analysis, process upsets can reduce the corrosion lifetime of equipment and even cause a system failure. 

P. Boden and D. Kingerley, Inorganic chemicals as metallic corrosion inhibitors. In Insights into Speciality Inorganic Chemicals (D. Thompson, ed.). Royal Society of Chemistry, Cambridge, 1995. 

To have insight into these mechanisms, we have performed and published several experiments on diffusion of corrosive, rinsing with different osmolar solutions to check the influence of osmolar conditioning of the cornea [8]. Further, we have tried to evaluate the diffusion of corrosive throughout the cornea [9]. In the latest experiments being published under www.acto.de, we present the effect of fluids of different osmolarities and their action on cells. Unpublished data give insight into... 

To evaluate these questions that are on one hand related to the corrosive and on the other hand related to the biological and chemical response to an accidental exposure, we have tried to set up experiments to give insight into the questions. 

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