Simulated current distribution around an electrolyte-wetted Mg-Al mixed compound (Al-rivet in a Mg-sheet).
The Corrosion and Surface Technology department (WZK), headed by Prof. Mikhail Zheludkevich, studies the corrosion mechanisms of different light-weight metallic systems with a special focus on Mg alloys. WZK contributes to the development of new more corrosion resistant or controlled degradable alloys and designs novel corrosion protection concepts for Mg components or hybrid structures. Specific use of modelling of partial aspects related to corrosion and coating processes assists in all the development activities.
The alloy development is performed in close collaboration with the departments of Mg Processing and Wrought Alloys with the aim to improve the corrosion properties of magnesium alloys further including the development of suitable recycling and degradable alloys.
Magnesium surface attacked by corrosion.
The work related to the design of new multifunctional corrosion protection systems and concepts including pretreatments such as cleaning and passivation as well as the development of new inorganic and organic coatings and multilayer systems with and without active corrosion protection. The latter should guarantee sufficient corrosion protection even in the case of mechanical damage of the coating.
In the case of degradable implants the coatings should extend and provide the required timescale for dissolution. Additional functionalities can be included such as delivery of drugs, stimulation of cell growth or antibacterial properties.
Calcium phosphate coating on magnesium alloy.
Corrosive environments can have a severe influence on the mechanical properties of magnesium alloys. Components and weldments can suffer from stress and fatigue corrosion cracking at loads well below the yield stress. The crack formation and growth in corrosive media as well as the related hydrogen embrittlement are studied and analysed.