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Galvanic
Pertaining to the current resulting from the coupling
of dissimilar electrodes in an electrolyte
galvanic
anode
A metal which because of its relative position in the
galvanic series, provides sacrificial protection to metals that are
more noble in the series, when coupled in an electrolyte.
galvanic
cell
A cell in which chemical change is the source of
electrical energy. It usually consists of two dissimilar conductors in
contact with each other and with an electrolyte. or of two similar
conductors in contact with each other and with dissimilar electrolytes.
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. See also galvanic corrosion.
galvanic
couple potential
See mixed potential.
galvanic
current
The electric current that flows between metals or
conductive nonmetal in a galvanic couple.
galvanic
series
A list of metals and alloys arranged according to
their relative corrosion potentials in a given environment. Compare with electromotive
series.
galvanize
To coat a metal surface with zinc using any of various
processes.
galvanneal
To produce a zinc-iron alloy coating on iron or steel
by keeping the coating molten after hot dip galvanizing until the zinc
alloys completely with the base metal.
galvanometer
An instrument for indicating or measuring a small
electric current by means of a mechanical motion derived from
electromagnetic or electrodynamic forces produced by the current.
galvanostatic
An experimental technique where by an electrode is
maintained at a constant current in an electrolyte.
gaseous
corrosion
Corrosion with gas as the only corrosive agent and
without any aqueous phase on the surface of the metal. Also called dry
corrosion.
gamma
iron
The face-centered cubic form of pure iron, stable from
910 to l400 ºC (1670 to 2550 ºF).
General
corrosion
A form of deterioration that is distributed more or
less uniformly over a surface; See uniform corrosion.
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Gibbs
free energy
The thermodynamic function 3G = 5H - TSS, where
H is enthalpy, T is absolute temperature. and S is
entropy. Also called free energy, free enthalpy, or Gibbs function.
glass
electrode
A glass membrane electrode used to measure pH
or hydrogen-ion activity.
grain
An individual crystal in a polycrystalline metal or
alloy; it may or may not contain twinned regions and subgrains; a portion of
a solid metal (usually a fraction of an inch in size), in which the atoms
are arranged in an orderly pattern.
grain
boundary
A narrow zone in a metal corresponding to the
transition from one crystallographic orientation to another, thus
separating one grain from another; the atoms in each grain are
arranged in an orderly pattern; the irregular junction of two adjacent
grains is known as a grain boundary.
grain-boundary
corrosion
Same as intergranular corrosion. See also interdendritic
corrosion.
graphitic
corrosion
Deterioration of gray cast iron in which the metallic
constituents are selectively leached or converted to corrosion products
leaving the graphite intact. The term graphic quotation is commonly
used to identify this form of corrosion, but is not recommended because of
its use in metallurgy for the decomposition of carbide to graphite;
deterioration of gray cast iron in which the metallic constituents are
selectively leached or converted to corrosion products leaving the graphite
intact.See also dealloying and selective leaching.
graphitization
A metallurgical term describing the formation of
graphite in iron or steel, usually from decomposition of iron carbide at
elevated temperatures. Not recommended as a term to describe graphitic corrosion.
green
liquor
The liquor resulting from dissolving molten melt irom
the kraft recovery furnace in water. See also kraft process and smelt.
Green
Rot
A form of high-temperature corrosion of
chromium-bearing alloys in which green chromium oxide (Cr2O3)
forms, but certain other alloy constituents remain metallic; some
simultaneous carburization is sometimes observed.
groundbed
A buried item, such as junk steel or graphite
rods, that serves as the anode for the cathodic protection of
pipelines or other buried structures. See also deep groundbed.
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