Light weight structures are a key technology for efficient utilization of resources and for manufacturing of high-quality products. The application of light weight metals in automotive structures reduces the weight of the vehicles and therefore their fuel consumption. This helps to reduce CO2 emission and to reach the EU-targets regarding climate protection. One approach towards implementation of lightweight structures is the substitution of multi-component steel parts by single component die cast parts. A further approach, which combines multiple aspects of lightweight construction is the application of multi-material-design – combining components of high-strength steel, Aluminium and Magnesium alloys and carbon fibre reinforced plastics (CFRP)s. CAR estimates, that 96% of all automotive programmes will consider the application of Aluminium as construction material for car bodies until the year 2030. Besides aluminium, Magnesium becomes more and more important, as its application will further reduce the weight of cars.
The biggest challenge concerning the application of lightweight metals is galvanic corrosion (contact corrosion), which occurs, when dissimilar metals (with dissimilar electrochemical potentials) are in electrically conductive contact with each other in presence of an electrolyte. To counteract corrosion (including contact corrosion), measures for corrosion protection are required. In automotive industry, corrosion protection is usually applied after assembly of the car body (and other parts of the car), by chemical pre-treatment – (degreasing; passivation by phosphating or zirconium oxide process) – and electrophoretic (usually cataphoretic) dip-coating, followed by application of a layer system of sealing, base coat and top coat. As of now, there is no pre-treatment process available, which would be compatible with Magnesium alloys in assembly with (galvanized) steel and/or aluminium alloys. Therefore, Magnesium coatings must be subjected to a cost-intensive off-line pre-coating before assembly. This circumstance hinders the broad application of Magnesium alloys in automotive Industry – as of now, the use of Magnesium parts is more or less limited to upper class, luxury- and sports cars, and only slowly penetrates into middle class cars of higher-priced brands. The project IBM-Sys aims to develop and test novel pre-treatment processes to pre-treat assemblies of Steel, Aluminium and Magnesium before electrophoretic dip-coating, without the need of an off-line treatment or coating of the Magnesium components.
Program: Mobilität der
Zukunft 15. Ausschreibung
Funding agency: FFG
Project duration: 12 months, 03/2021-02/2022