Nace CP 1, Course Manual

Page: 260 / 535

NACE GLOSSARY OF CORROSION-RELATED TERMS
©
2002, NACE International. This publication may not be reprinted without the written consent of NACE International.
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the polarization resistance when
the scan rate is low and any
uncompensated resistance is
small relative to the polarization
resistance.)
POLARIZED POTENTIAL
The potential across the
structure/electrolyte interface that
is the sum of the corrosion
potential and the cathodic
polarization.
POLYESTER
Type of resin formed by the
condensation of polybasic and
monobasic acids with polyhydric
alcohols.
POSTWELD HEAT
TREATMENT
Heating and cooling a weldment
in such a way as to obtain
desired properties.
POTENTIAL-pH DIAGRAM
A graphical method of
representing the regions of
thermodynamic stability of
species for metal/electrolyte
systems (also known as
Pourbaix
diagram ).
POTENTIODYNAMIC
Refers to a technique wherein
the potential of an electrode with
respect to a reference electrode
is varied at a selected rate by
application of a current through
the electrolyte.
POTENTIOKINETIC
[See Potentiodynamic. ]
POTENTIOSTAT
An instrument for automatically
maintaining a constant electrode
potential.
POTENTIOSTATIC
Refers to a technique for
maintaining a constant electrode
potential.
POT LIFE
The elapsed time within which a
coating can be effectively applied
after all components of the
coating have been thoroughly
mixed.
POULTICE CORROSION
[See Deposit Attack. ]
POURBAIX DIAGRAM
[See Potential-pH Diagram. ]
POWER TOOL CLEANING
Removal of loose rust, loose mill
scale, and loose paint to degree
specified by power tool chipping,
descaling,
sanding, wire
brushing, and grinding. [See
SSPC-SP 3.]
PRECIPITATION
HARDENING
Hardening caused by the
precipitation of a constituent from
a supersaturated solid solution.
PRIMARY PASSIVE
POTENTIAL
The potential corresponding to
the maximum active current
density (critical anodic current
density) of an electrode that
exhibits active-passive corrosion
behavior.
PRIME COAT
[See Primer .]
PRIMER
A coating material intended to be
applied as the first coat on an
uncoated surface. The coating is
specifically formulated to adhere
to and protect the surface as well
as to produce a suitable surface
for subsequent coats. [Also
referred to
as Prime Coat .]
PROFILE
Anchor pattern on a surface
produced by abrasive blasting or
acid treatment.
PROTECTIVE COATING
A coating applied to a surface to
protect the substrate from
corrosion.
R
REDUCTION
Gain of electrons by a constituent
of a chemical reaction.
REFERENCE
ELECTRODE
An electrode whose open-circuit
potential is constant under similar
conditions of measurement,
which is used for measuring the
relative potentials of other
electrodes.
REFERENCE HALF-CELL
[See Reference Electrode. ]
RELATIVE HUMIDITY
The ratio, expressed as a
percentage, of the amount of
water vapor present in a given
volume of air at a given
temperature to the amount
required to saturate the air at that
temperature.
REMOTE EARTH
A location on the earth far
enough from the affected
structure that the soil potential
gradients associated with
currents entering the earth from
the affected structure are