Metals and their alloys are subject to electrochemical corrosion when they come into contact with an electrolyte. Physiological solutions in the body, such as saliva or blood, act as electrolytes. As a result, the implant surface begins to corrode. This can lead to the dissolution of the metal with the accompanying release of ions. However, metal compounds can also form and protect the surface from corrosive attacks, known as (re)passivation.

Our current focus is on investigating the corrosion behavior of dental alloys using examples from prosthetics and orthodontics. The composition of the alloy plays a role here, but also the fact that material pairings of different alloy compositions (galvanic element) frequently occur in the oral cavity. Another aspect is the joining techniques [(laser) welding, soldering] used in the manufacture and repair of dental restorations. In addition to the joining technique, the influence of heat also leads to changes in the microstructure.

We investigate these issues using current density potential measurements (linear polarization) on various alloys and their material pairings and the subsequent analysis of characteristic parameters such as the resting potential, the corrosion potential, the corrosion resistance and the corrosion rate through to the breakthrough potential. In the case of iron-free alloys, the repassivation behaviour can also be investigated using cyclic polarization.

The electrochemical measurement is accompanied by morphological characterization (light and electron microscopy) as well as qualitative element analysis (EDX) and quantitative ion analysis (ICP-MS).