Galvanization refers to any of several electrochemical processes named after the Italian scientist Luigi Galvani. Electrochemistry is the science of the reactions that can take place at the interface of an electronic conductor (the electrode, which can be a metal or a semiconductor including graphite) and an ionic conductor (the electrolyte). ... Luigi Galvani Luigi Galvani (September 9, 1737–December 4, 1798) was an Italian physician and physicist who lived and died in Bologna. ...

1. Originally, galvanization was the administration of electric shocks (in the 19th century also termed Faradism, after Michael Faraday). It stemmed from Galvani's induction of twitches in severed frogs' legs, by his accidental generation of electricity. This archaic sense is the origin of the meaning of galvanized when meaning 'stirred to sudden action'. Its claims to health benefits have largely been disproven, except for some limited uses in psychiatry. See also: Galvanism, Violet wand
2. Later the word was used for processes of electrodeposition. This remains a useful and broadly applied technology, but the term "galvanization" has largely come to be associated with zinc coatings, to the exclusion of other metals.
3. In current use, it typically means hot-dip galvanizing, a chemical process that is used to coat steel or iron with zinc. This is done to reduce corrosion (specifically rusting) of the ferrous item; while it is accomplished by non-electrochemical means, it serves an electrochemial purpose.

The remainder of the article is about zinc anti-corrosion coatings. Michael Faraday Michael Faraday (September 22, 1791 – August 25, 1867) was a British scientist (a physicist and chemist) who contributed significantly to the fields of electromagnetism and electrochemistry. ... Genera Afrana Amietia Amnirana Amolops Aubria Batrachylodes Ceratobatrachus Chaparana Conraua Discodeles Euphlyctis Fejervarya Hildebrandtia Hoplobatrachus Huia Indirana Ingerana Lankanectes Lanzarana Limnonectes Meristogenys Micrixalus Minervarya Nannophrys Nanorana Nyctibatrachus Occidozyga Paa Palmatorappia Platymantis Pseudoamolops Pterorana Ptychadena Pyxicephalus Rana Sphaerotheca Staurois Strongylopus Tomopterna Frogs are amphibians in the Order Anura, which includes true... Electricity is a general term applied to phenomena involving a fundamental property of matter called an electric charge. ... Adjective archaic (more archaic, most archaic) From an earlier period and no longer in common use; of or characterized by antiquity or archaism, antiquated. ... Psychiatry is the branch of medicine that diagnoses, treats, and studies mental illness and behavioral conditions. ... In biology, galvanism is the contraction of a muscle that is stimulated by an electric current. ... A violet ray or violet wand is a quack medical device used for the application of low current, high frequency electricity to the body using a Tesla coil for purposes of electrotherapy. ... Electroplating is the the coating of an electrically conductive item with a layer of metal using electrical current. ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... Hot-dip galvanizing is the process of coating iron or steel with a thin zinc layer by passing the steel through a molten bath of zinc at a temperature of around 450°C. Zinc rusts to form zinc oxide, a fairly strong material that stops further rusting, protecting the steel... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... Corrosion, atmospheric and biologic (Barnacles) Corrosion is deterioration of useful properties in a material due to reactions with its environment. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ...

Zinc coatings prevent oxidation of the protected metal by forming a barrier, and by acting as a sacrificial anode if this barrier is damaged. Zinc oxide is a fine white dust that (in contrast to iron oxide) does not cause a breakdown of the substrate's surface integrity as it is formed. Indeed the zinc oxide, if undisturbed, can act as a barrier to further oxidation, in a way similar to the protection afforded to aluminium and stainless steels by their oxide layers. This article or section should be merged with Cathodic protection A galvanic anode, also known as a sacrificial anode, is used to protect metals from galvanic corrosion, by the use of a metal electrode which is itself consumed instead in an anodic oxidation reaction. ... Zinc oxide is a chemical compound with formula ZnO. It is nearly insoluble in water but soluble in acids or alkalis. ... The word substrate can mean the following: In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ... The most fundamental reactions in chemistry are the redox processes. ... Passivation is the process of making a material passive in relation to another material prior to using the materials together. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... In metallurgy, stainless steel (inox) is defined as a ferrous alloy with a minimum of 10. ...

Hot dip galvanizing deposits a thick, robust layer that may be more than is necessary for the protection of the underlying metal in some applications. This is the case in automobile bodies, where additional rust proofing paint will be applied. Here, a thinner form of galvanizing is applied by electroplating, called "electro-galvanized". Where the metal is not to be painted or is to be used in critical exposure conditions such as near salt water, "hot-dip galvanized" is preferred for its long term durability. Galvanized nails are now usually electro-galvanized but these are greatly inferior to the hot-dipped kind, particularly when used outdoors. A small variety of cars, the most popular kind of automobile. ... Electroplating is the coating of an electrically conductive item with a layer of metal using electrical current. ...

Galvanic protection (also known as sacrificial-anode or cathodic protection) can be achieved by connecting zinc both electronically (often by direct bonding to the protected metal) and ionically (by submerging both into the same body of elecrolyte, such as a drop of rain). In such a configuration the zinc is absorbed into the electrolyte in preference to the metal that it protects, and maintains that metal's structure by inducing an electric current. In the usual example, ingots of zinc are used to protect a boat's hull and propellers, with the ocean as the common electrolyte. This article or section should be merged with Cathodic protection A galvanic anode, also known as a sacrificial anode, is used to protect metals from galvanic corrosion, by the use of a metal electrode which is itself consumed instead in an anodic oxidation reaction. ... Aluminium anodes mounted on a steel jacket structure Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell. ... An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ...

As noted previously, both mechanisms are often at work in practical applications. For example, the traditional measure of a coating's effectiveness is resistance to a salt spray. Thin coatings cannot remain intact indefinitely when subject to surface abrasion, and the galvanic protection offered by zinc can be sharply contrasted to more noble metals. As an example, a scratched or incomplete coating of chromium actually exacerbates corrosion of the underlying steel, since it is less electrochemically active than the substrate. A spray of water originating from ocean waves. ... General Name, Symbol, Number chromium, Cr, 24 Chemical series transition metals Group, Period, Block 6, 4, d Appearance silvery metallic Atomic mass 51. ...

Galvanized surface with visible spangle

The size of crystallites in galvanized coatings is an aesthetic feature, known as spangle. By varying the number of particles added for heterogeneous nucleation and the rate of cooling in a hot-dip process, the spangle can be adjusted from an apparently uniform surface (crystallites too small to see with the naked eye) to grains several centimeters wide. Visible crystallites are rare in other engineering materials. Image:Galvanized surface. ... Image:Galvanized surface. ... A crystallite is a domain of solid-state matter that has the same structure as a single crystal. ... Bubbles in a soft drink each nucleate independently, responing to a decrease in pressure. ...

See also

• Hot-dip galvanizing

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Galvanization