"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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