galvanisk

Galvanisk (galvanic) refers to processes driven by electrochemical potential differences between two electrodes in an electrolyte, producing an electric current. In electrochemistry, galvanic reactions are spontaneous redox processes that convert chemical energy into electrical energy.

A galvanic cell consists of two conducting electrodes immersed in an electrolyte and connected by an external circuit. At the anode, oxidation occurs and electrons are released; at the cathode, reduction consumes electrons. The resulting cell potential, Ecell, equals the difference between the reduction potentials of the two electrodes. If Ecell is positive, the reaction proceeds spontaneously and current flows; reversing the potentials leads to an electrolytic process requiring external power.

Common examples include the Daniell cell (zinc and copper) and modern batteries that rely on galvanic reactions to store and release energy. Applications span portable power sources, and sacrificial galvanic protection in metal structures, where a more active metal corrodes in preference to the protected material.

Galvanic corrosion arises when two different metals are electrically connected in an electrolyte; the less noble metal acts as an anode and corrodes, while the more noble metal is protected as a cathode. Mitigation strategies include insulating joints, applying protective coatings, using insulating materials, or placing a sacrificial anode of a more active metal.

The term is contrasted with electrolytic (non-spontaneous) processes, where an external power source drives a redox reaction. The galvanic series orders metals by their electrode potentials and helps predict corrosion risk in mixed-metal contact.