Swerea works with modelling of the corrosion progression in various sectors, providing valuable information that is applied in materials selection and corrosion protection, service-life prediction, design of components and plant facilities, as well as an aid to improved understanding of corrosion mechanisms.
Corrosion modelling with numerical methods is often applied in studies of galvanic corrosion and cathodic protection. Detailed models are used to construct models of local corrosion; pitting and microgalvanic cells. Statistical models for atmospheric corrosion are also developed.
Galvanic corrosion and cathodic protection
Corrosion-related problems often affect the infrastructure, such as railways, tramlines and pipelines. In many cases, problems can be reduced to two-dimensional resistance grids resulting in equation systems that are large but easily solved. In more complicated cases, Finite Element Methods (FEM) are used, for example, when objects have to be represented in three dimensions.
Pitting and microgalvanic cells
Local chemistry has a great bearing on local corrosion. Environment controls corrosion, but reaction products from corrosion processes also change the environment, at least locally. Electrochemical reaction rates, local equilibrium and reaction kinetics of precipitation reactions, as well as transport mechanisms via diffusion and electromigration are included in the models. For corrosion of alloys in natural environments the chemical systems are often large and lead to relatively long computation times for FEM computations in 2D or 3D.
Statistical models for atmospheric corrosion
Determining corrosivity in different parts of the world is often an advantage for companies wishing to establish themselves on new markets, as well as when selecting materials. We have produced dose-response functions that describe the degree of corrosion in relation to different meteorological parameters and contaminant concentrations. These functions are based on data gathered from locations throughout the world. Many metals and alloys have been subjected to atmospheric corrosion tests according to standardised methods in various programmes, a number of which have been coordinated by Swerea. Results from individual observations have been compiled in the database program KorrField, which also contains a computation module that predicts and visualises corrosivity under different environmental parameters.
Contact and more information
claes.taxen [at] ri.se