Galvanic

Galvanic refers to processes and devices in electrochemistry in which electrical energy is produced by a spontaneous redox reaction. The term honors Luigi Galvani, an 18th-century Italian physician whose experiments on animal electricity helped establish the foundations of galvanic phenomena. In modern usage, galvanic is applied to galvanic cells, galvanic corrosion, and related concepts.

A galvanic cell consists of two electrodes of different materials immersed in electrolytes and connected by an external circuit. In the cell, oxidation occurs at the anode and reduction at the cathode, causing electrons to flow through the external circuit and establishing a potential difference, or cell potential, between the electrodes. The overall reaction is spontaneous when the cell potential is positive. Standard cell potentials are tabulated for common electrode couples and are used to predict reaction feasibility and energy yield.

Galvanic corrosion occurs when two dissimilar metals are connected through an electrolyte. The more active metal acts as the anode and corrodes, while the more noble metal is protected as the cathode. Factors include metal pair, electrolyte conductivity, temperature, and the relative surface areas of the metals. Mitigation strategies include selecting compatible metals, using insulating barriers, applying protective coatings, employing sacrificial anodes, and ensuring proper electrical isolation in structures.

Other uses include galvanic isolation in electronics, which prevents current flow between circuits to avoid unwanted coupling, and galvanic sensors or cells used in batteries and corrosion monitoring.