Corrosion Terminology - G's

galvanic anode—a metal that provides sacrificial protection to another metal that is more noble when electrically coupled in an electrolyte. This type of anode is the electron source in one type of cathodic protection.

galvanic corrosion—accelerated corrosion of a metal because of an electrical contact with a more noble metal or nonmetallic conductor in a corrosive electrolyte.

galvanic couple—a pair of dissimilar conductors, commonly metals, in electrical contact in an electrolyte.

galvanic current—the electric current flowing between metals or conductive nonmetals in a galvanic couple.

galvanic series—a list of metals and alloys arranged according to their corrosion potentials in a given environment.

galvanized coating(1)  a coating of zinc on steel that contains an interfacial interdiffusion layer of zinc and iron, forming a metallurgical bond at the steel surface; (2) [not preferred] a coating of metallic zinc applied by hot-dipping, mechanical means,electroplating or other means.

galvanizing(1) applying a coating of zinc. (2) see galvanized coating.

galvanodynamic—refers to a technique wherein current, continuously varied at a selected rate, is applied to an electrode in an electrolyte.

galvano staircase—refers to a galvano step technique for polarizing an electrode in a series of constant current steps wherein the time duration and current increments or decrements are equal for each step.

galvanostatic—refers to a technique wherein an electrode is maintained at a constant current in an electrolyte.

galvano step—refers to a technique wherein an electrode is polarized in a series of current increments or decrements.

general corrosion—corrosion that is distributed more-or-less uniformly over the surface of a material.

grain—an individual crystal in a solid metal or alloy in which the atoms are arranged in an orderly pattern.

grain boundary—an interface separating two grains.

grain dropping—the dislodgement and loss of a grain or grains (crystals) from a metal surface as a result of inter granular corrosion.

graphitic corrosion—deterioration of cast iron wherein the metallic constituents are selectively leached or converted to corrosion products, leaving the graphitic particles intact.[should not be used as a term to describe graphitization]

graphitization—the formation of graphite in iron or steel, usually from decomposition of iron carbide at elevated temperatures. [should not be used as a term to describe graphitic corrosion]

graycast iron—cast iron that displays a gray fracture surface as a result of the presence of flake graphite.

grit—small particles of hard material (e.g., iron, steel, or mineral) with irregular shapes that are commonly used as an abrasive in abrasive blast cleaning.

gritblasting—abrasive blast cleaning using grit as the abrasive.

ground bed—one or more anodes installed below the earth's surface for the purpose of supplying cathodic protection current.