Corrosion Material Library
The Corrosion material library contains polarization data (local current density versus electrode potential) for a number of different metals in various electrolytes. Equilibrium potentials (potential at zero current density) are also provided.
All corrosion material data in the library is based on open literature sources. These can be viewed by clicking the Edit/Show Property Information button in the info column in the Output Properties section of the Property Group subnodes once a Material node has been added to the model.
Polarization curves are typically added as interpolation polynomials, using linear extrapolation and interpolation. Polarization data is added with respect to the same reference electrode as in the scientific literature source. The material node will, however, by definition assume the voltage input from the physics to the material to be versus a Standard Hydrogen Electrode (SHE). Conversion of the potential input versus SHE value to the relevant reference is hence done locally within the Material node before calling the interpolation polynomial function. On the physics side, using another reference electrode than SHE for postprocessing and user-defined equilibrium potentials can be accomplished by the Physics vs. Materials Reference Electrode Potential setting on the physics top node. The reference electrode in the original data is stated in the Property Information but also in the descriptions of the local properties defined by the material node, where applicable.
Equilibrium (open circuit) potential data is also provided, defined as the potential for which the current is zero or the magnitude of the current is at its minimum in the experimental polarization curve. Equilibrium potentials are also defined versus the reference in the original data and then converted to equilibrium potentials versus SHE on the Materials node itself.
The equilibrium (open circuit) potential has no impact on the local current density expression defined by the Material node. However, the equilibrium potential could be used by the physics during Primary Current Distribution simulations, the Current Distribution Initialization (primary option) study step, and for calculating electrode reaction heat sources. It should, however, be noted that for polarization data representing the sum of multiple reactions (for example, oxygen reduction plus metal dissolution in many corrosion polarization measurements), there is, in a thermodynamical sense, no well-defined equilibrium for the sum of the reactions, and the equilibrium potential value provided by the Material node should, in this case, not be used for deriving electrochemical heat sources.