Nace CP 1, Course Manual

Page: 247 / 535

NACE GLOSSARY OF CORROSION-RELATED TERMS
©
2002, NACE International. This publication may not be reprinted without the written consent of NACE International.
Page 1 of 18
A
ABRASIVE
Small particles of material that
are propelled at high velocity to
impact a surface during abrasive
blast cleaning.
ABRASIVE BLAST
CLEANING
Cleaning and roughening of a
surface produced by the high-
velocity impact of an abrasive
that is propelled by the discharge
of pressurized fluid from a blast
nozzle or by a mechanical device
such as a centrifugal blasting
wheel. (Also referred to as
Abrasive Blasting .)
ACCELERATOR
A chemical substance that
increases the rate at which a
chemical reaction (e.g., curing)
would otherwise occur.
ACRYLIC
Type of resin polymerized from
acrylic acid, methacrylic acid,
esters of these acids, or
acrylonitrile.
ACTIVATOR
A chemical substance that
initiates and accelerates a
chemical reaction (e.g., curing).
Heat and radiation may also
serve as activators for some
chemical reactions.
ACTIVE
(1) The negative direction of
electrode potential. (2) A state
of a metal that is corroding
without significant influence of
reaction product.
AERATION CELL
[See Differential Aeration Cell. ]
AIR DRYING
Process by which an applied wet
coat converts to a dry coating
film by evaporation of solvent or
reaction with oxygen as a result
of simple exposure to air without
intentional addition of heat or a
curing agent.
AIRLESS SPRAYING
Process of spraying coating
liquids using hydraulic pressure,
not air pressure, to atomize.
ALKYD
Type of resin formed by the
reaction of polyhydric alcohols
and polybasic acids, part of
which is derived from saturated
or unsaturated oils or fats.
ALLIGATORING
Pronounced wide cracking over
the surface of a coating, which
has the appearance of alligator
hide.
AMPHOTERIC METAL
A metal that is susceptible to
corrosion in both acid and
alkaline environments.
ANAEROBIC
Free of air or uncombined
oxygen.
ANION
A negatively charged ion that
migrates through the electrolyte
toward the anode under the
influence of a potential gradient.
ANODE
The electrode of an
electrochemical cell at which
oxidation occurs. Electrons flow
away from the anode in the
external circuit. Corrosion
usually occurs and metal ions
enter the solution at the anode.
ANODE CAP
An electrical insulating material
placed over the end of the anode
at the lead wire connection.
ANODE CORROSION
EFFICIENCY
The ratio of the actual corrosion
(mass loss) of an anode to the
theoretical corrosion (mass loss)
calculated from the quantity of
electricity that has passed
between the anode and cathode
using Faraday's law.
ANODIC INHIBITOR
A chemical substance that
prevents or reduces the rate of
the anodic or oxidation reaction.
ANODIC POLARIZATION
The change of the electrode
potential in the noble (positive)
direction caused by current
across the electrode/electrolyte
interface. [
See Polarization .]
ANODIC PROTECTION
Polarization to a more oxidizing
potential to achieve a reduced
corrosion rate by the promotion
of passivity.
ANODIZING
Oxide coating formed on a metal
surface (generally aluminum) by
an electrolytic process.
ANOLYTE
The electrolyte adjacent to the
anode of an electrochemical cell.
ANTIFOULING
Preventing fouling. [See
Fouling. ]