Nace CP 1, Course Manual

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NACE GLOSSARY OF CORROSION-RELATED TERMS
©
2002, NACE International. This publication may not be reprinted without the written consent of NACE International.
Page 11 of 18
corrosion ).
INTERGRANULAR
STRESS CORROSION
CRACKING
Stress corrosion cracking in
which the cracking occurs along
grain boundaries.
INTERNAL OXIDATION
The formation of isolated
particles of oxidation products
beneath the metal surface.
INTUMESCENCE
The swelling or bubbling of a
coating usually caused by
heating. [The term is commonly
used in aerospace and fire-
protection applications.]
ION
An electrically charged atom or
group of atoms.
IR DROP
The voltage across a resistance
in accordance with Ohm’s Law.
IRON ROT
Deterioration of wood in contact
with iron-based alloys.
K
KNIFE-LINE ATTACK
Intergranular corrosion of an
alloy along a line adjoining or in
contact with a weld after heating
into the sensitization temperature
range.
L
LAMELLAR CORROSION
[See Exfoliation Corrosion. ]
LANGELIER INDEX
A calculated saturation index for
calcium carbonate that is useful
in predicting scaling behavior of
natural water.
LINE CURRENT
The direct current flowing on a
pipeline.
LINING
A coating or layer of sheet
material adhered to or in intimate
contact with the interior surface
of a container used to protect the
container against corrosion by its
contents and/or to protect the
contents of the container from
contamination by the container
material.
LIQUID METAL
CRACKING
Cracking of a metal caused by
contact with a liquid metal.
LONG-LINE CURRENT
Current though the earth
between an anodic and a
cathodic area that returns along
an underground metallic
structure.
LOW-CARBON STEEL
Steel having less than 0.30%
carbon and no intentional
alloying additions.
LOW-PRESSURE WATER
CLEANING
Water cleaning performed at
pressures less than 34 MPa
(5,000 psig).
LUGGIN PROBE
A small tube or capillary filled
with electrolyte, terminating close
to the metal surface of an
electrode under study, which is
used to provide an ion-
conducting path without diffusion
between the electrode under
study and a reference electrode.
M
MARTENSITE
A hard supersaturated solid
solution of carbon in iron
characterized by an acicular
(needle-like) microstructure.
METAL DUSTING
The catastrophic deterioration of
a metal exposed to a
carbonaceous gas at elevated
temperature.
METALLIZING
The coating of a surface with a
thin metal layer by spraying, hot
dipping, or vacuum deposition.
MILL SCALE
The oxide layer formed during
hot fabrication or heat treatment
of metals.
MIXED POTENTIAL
A potential resulting from two or
more electrochemical reactions
occurring simultaneously on one
metal surface.