Galvanic corrosion of metal/ceramic coupling

• The galvanic corrosion of a ceramic/metal coupling is investigated.
• The specific conductivity of the SiC-based ceramic plays a key role.
• If the specific conductivity high enough, the corrosion is oxygen diffusion limited.
• In all investigated cases the ceramic represents the cathodic site of the coupling.

The galvanic corrosion risk of metal/SiC-based ceramic coupling in 3.5 wt% NaCl aqueous solution is investigated. Electrochemical measurements as linear sweep voltammetry and galvanic corrosion tests according to DIN-50919 were used. The results clearly show that the resistivity of the SiC-based ceramic plays the key role in the understanding of galvanic corrosion between metal and ceramic. In all cases the ceramic represents the cathodic site of the coupling. The corrosion rate is dominated by the electrical resistance of the ceramic.