The Corrosion Module, which is new in version 4.3, is intended for the modeling of corrosion and corrosion protection. The descriptions made available by the module are based on current and potential distribution in galvanic cells. Its modeling capabilities covers galvanic corrosion, cathodic protection, anodic protection, and sacrificial anode protection.
The Corrosion Module consists of a number of chemical species transport, fluid flow, heat transfer, electrochemistry, and corrosion interfaces. These physics interfaces describe the potential in the electrolyte and in the corroding or protected metallic structure. The electrode reactions can be described using arbitrary electrode kinetic expressions of the overpotential for the anodic and cathodic reactions. The potential and current distribution can also include the influence of mass transport and heat transfer, which means that the Corrosion Module makes it possible to model composition and temperature in a corrosion cell in detail. The ability to account for mass transport in the electrolyte allows for modeling of corrosion caused by variations in, for example, salt concentration, oxygen concentration, and pH.
The basis of the Corrosion Module is the mass and current balances in the electrolyte an in the corroding or protected metal structure. In the electrolyte, the current balance is defined together with individual species balances for the charged species and the electroneutrality condition. In the metallic structure, the current balance is described using Ohm’s law for the current density. The electron transfer reactions, at the interface between the metallic structure and the electrolyte, couple the transport processes in the electrolyte with the current flowing in the metallic structure. The module contains predefined formulations for the abovementioned processes. In addition, the module modifies the Heat Transfer interfaces so that predefined terms for heat sources caused by losses in the electrochemical process are described properly.