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Corrosion Glossary - L
a fast-drying usually clear coating
that is highly flammable and dries by solvent evaporation only. Can be reconstituted
after drying by adding solvent.
- Lamellar corrosion:
a form of corrosion in which the expanding corrosion products stack up as layers.
Similar to exfoliation of
high strength aluminum alloys.
- Laminar flow: the flow of fluid in which
the flow paths are in smooth, parallel lines, with essentially no mixing and
A calculated number used to predict the calcium carbonate (CaCO3) stability
of a water; that is, whether a water will precipitate, dissolve, or be in equilibrium
with calcium carbonate. It is sometimes
erroneously assumed that
any water that tends to dissolve calcium carbonate will always be corrosive.
- Lanthanides: commonly referred to as
'Rare Earth' metals. Examples: Neodymium,
Lanthanum and Yttrium.
- Lap joint: a welded joint in which two
overlapping metal parts are joined by means of a fillet, plug or slot weld.
- Lapping: rubbing two surfaces together,
with or without abrasives, for the purpose obtaining extreme dimensional accuracy
or superior surface finish.
- Laser alloying: the application of a
powder to a surface followed by fusing and alloying into the surface via the
heat from an impinging laser.
- Laser glazing: the melting and quenching
of a surface to form a fine grained structure or 'glaze'.
- Laser hardening: the localized surface
heating of a medium carbon steel by an incident laser so that the temperature
is raised above 900oC. The part is quenched (or self-quenches by virtue of the
remaining cool bulk of the component) and tempered to produce a hard martensitic
structure at the surface.
paint: general term used for water-based emulsion
paints made with synthetic binders
such as 100% acrylic, vinyl acrylic, terpolymer or styrene acrylic. A stable
emulsion of polymers and pigment in water.
- Leaching: a process in which
metal is extracted from mined ore
by means of adding a soluble substance. Commonly used in
- Leakage: the uncontrolled quantity of
fluid which enters or leaves through the enclosure of air or gas passages.
- Life Cycle Costing: a process of estimating
and assessing the total costs of ownership, operation and maintenance of an
item of equipment during its projected equipment life. Typically used in comparing
alternative equipment design or purchase options in order to select the most
- Lime: the common name for calcium oxide
(CAO). Hydrated lime is calcium hydroxide, Ca(OH)2, the cement in
- Lime scale: hard water
a high percentage of calcium carbonate.
- Limestone: a sedimentary rock, largely
calcium carbonate, and usually also
containing significant amounts of magnesium carbonate.
- Linear alkyl sulfonate: a term applied
to a family of straight chain chemical compounds, widely used as detergents;
sometimes called "soft" detergents because they are more readily degraded to
simpler substances by biological action than the previously used alkyl benzene
- Lining: the material used on the furnace
side of a furnace wall. it is usually of high grade refractory tile or brick
or plastic refractory material.
- Liquid impingement erosion: progressive
loss of material from a solid surface due to continue exposure to impacts by
liquid drops or jets.
- Liquid metal
brittle failure of a normally ductile metal when in contact with a liquid metal
and subsequently stressed in tension.
- Liquid metal fast breeder reactor (LMFBR):
nuclear reactor that uses a liquid metal, such as sodium, to transfer heat from
the reactor to a steam generator. A breeder reactor makes more fuel than it
uses by converting uranium-238 to plutonium-239.
- Liquid penetrant examination (PT): a
method of nondestructive examination. Typical discontinuities found with this
method are cracks and laminations
- Liter: the basic metric unit of volume;
3.785 liters equal 1 U.S. gallon; 1 liter of water weighs 1000 grams.
- Lithopone: a white pigment of barium
sulfate and zinc sulfide.
- Load: the rate of output required; also
the weight carried.
- Load factor: the ratio of the average
load in a given period to the maximum load carried during that period.
- Local action
corrosion: corrosion caused by local corrosion cells on a metal
- Local cell: a
galvanic cell resulting
from inhomogeneities between areas on a metal surface in an electrolyte. The
inhomogeneities may be of physical or chemical nature in either the metal or
- Local corrosion
cell: an electrochemical
cell created on a metal surface because of a difference in potential between
adjacent areas on that surface.
corrosion: corrosion at discrete sites, for example, pining,
crevice corrosion, and stress corrosion cracking.
- Logistic support analysis (LSA): A methodology
for determining the type and quantity of logistic support required for a system
over its entire lifecycle. Used to determine the cost effectiveness of asset
- Long-line current: electric current
through the earth from an anodic to a cathodic area of a continuous metallic
structure. (Usually used only where the areas are separated by considerable
distance and where the current results from
- Low water cutoff: safety device that
shuts off the boiler/burner in the event of low water, preventing pressure vessel
- LPPS: see vacuum or low pressure plasma
- Lubricant: any substance interposed
between two surfaces for the purpose of reducing the friction or wear between
- Lug: any projection, like an ear, used
for supporting or grasping.
- Luggin probe or
Luggin-Haber capillary: a
device used in measuring the potential of an electrode with a significant current
density imposed on its surface. (The probe minimizes the IR drop that would
otherwise be included in the measurement and without significantly disturbing
the current distribution on the specimen.