"THE GALVANIZATION PROCESS"
(Source: Wikipedia Encyclopedia)
In current use, "galvanization" typically means hot-dip galvanizing, a metallurgical
process that is used to coat steel or iron with zinc. This is done to prevent corrosion
(specifically rusting) of ferrous items; while it is accomplished by
non-electrochemical means, it serves an electrochemical purpose.
Galvanization is the
process of coating a base metal, such as iron, with a thin layer of zinc to
protect the base metal from corrosion. The zinc layer protects the base metal
even when there are cracks or small gaps in the coating, because oxygen reacts
more readily with zinc than with the exposed base metal.
Hot-dip galvanized steel has been effectively used for more than 150 years. The value of hot-dip galvanizing stems from the relative corrosion resistance
of zinc, which, under most service conditions, is considerably better than iron
and steel. In addition to form a physical barrier against corrosion, zinc,
applied as a hot-dip galvanized coating, cathodically protects exposed steel.
Furthermore, galvanizing for protection of iron and steel is favored because of
its low cost, the ease of application, and the extended maintenance-free
service that it provides.
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Originally, galvanization was the administration of electric shocks (in the
19th century also termed Faradism, after Michael Faraday).
It stemmed
from Luigi Galvani's induction of twitches in severed frogs' legs, by his accidental
generation of electricity.
It had been found that a charge applied to
the spinal cord of a frog could generate muscular spasms throughout its body. Charges
could make frog legs jump even if the legs were no longer attached to a frog. While
cutting a frog leg, Galvani's steel scalpel touched a brass hook that was
holding the leg in place. The leg twitched.
In honor of Galvani's research, Volta coined the
term galvanism for a direct current of electricity produced by chemical action.
Galvani's name is still associated with electricity in the words galvanism and
galvanization.
Later, the word "galvanic" was used for processes of electro deposition. 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.
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