ASTM B374-96(2003)
(Terminology)Standard Terminology Relating to Electroplating
Standard Terminology Relating to Electroplating
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Endorsed by American
Designation:B374–96 (Reapproved 2003) Electroplaters’ Society
Endorsed by National
Association of Metal Finishers
Standard Terminology Relating to
Electroplating
This standard is issued under the fixed designation B374; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
These definitions correspond to interpretations as applied to electroplating and do not necessarily
correspond to the definitions used in other fields.
abrasive blasting—a process for cleaning or finishing by anode efficiency—current efficiency of a specified anodic
means of an abrasive directed at high velocity against the process.
work piece. anode film—(1)thelayerofsolutionincontactwiththeanode
activator—in diffusion coatings, a chemical, usually a halide that differs in composition from that of the bulk of the
salt, that enters into a reaction with the source or master solution. (2) The outer layer of the anode itself consisting of
alloy, depositing the source on the substrate. oxidation or reaction products of the anode metal.
activation—elimination of a passive condition on a surface. anode polarization—See polarization.
activity (ion)—the ion concentration corrected for deviations anodic coating—a protective, decorative, or functional coat-
from ideal behavior. Concentration multiplied by activity ing, formed by conversion of the surface of a metal in an
coefficient. electrolytic oxidation process.
addition agent—a material added in small quantities to a anodizing—an electrolytic oxidation process in which the
solution to modify its characteristics. It is usually added to a surface of a metal, when anodic, is converted to a coating
platingsolutionforthepurposeofmodifyingthecharacterof having desirable protective, decorative, or functional prop-
a deposit. erties.
adhesion—the attractive force that exists between an elec- anolyte—theportionofelectrolyteinthevicinityoftheanode;
trodeposit and its substrate that can be measured as the force in a divided cell, the portion of electrolyte on the anode side
required to separate an electrodeposit and its substrate. of the diaphragm.
adhesion, practical, n—the force or work required to detach anti-pitting agent—an addition agent for the specific purpose
or remove a coating from the underlayer or substrate; it can of preventing gas pits in a deposit.
be measured in terms of peel, pull, or shear strength as an autocatalytic plating—deposition of a metal coating by a
experimentally determined quantity. controlled chemical reduction, catalyzed by the metal or
aluminizing—forming of an aluminum or aluminum alloy alloy being deposited.
coatingonametalbyhotdipping,hotspraying,ordiffusion. automatic machine (or conveyor)—a machine for mechani-
amorphous—noncrystalline, or devoid of regular structure. cally processing parts through treatment cycles, such as
ampere—the current that will deposit silver at the rate of cleaning, anodizing, or plating.
0.0011180 g/s. Current flowing at the rate of 1 C/s. automatic plating: (1) full—plating in which the cathodes are
−8
˚
angström unit (A)—10 cm. automatically conveyed through successive cleaning and
anion—a negatively-charged ion. plating tanks. (2) semi—plating in which the cathodes are
anode—the electrode in electrolysis, at which negative ions conveyed automatically through only one plating tank.
are discharged, positive ions are formed, or other oxidizing auxiliary anode—a supplementary anode employed during
reactions occur. electrodeposition to achieve a desired thickness distribution
anode corrosion—dissolution of anode metal by the electro- of the deposit.
chemical action in an electrolytic cell. auxiliary cathode—See thief.
back emf (electromotive force)—the potential set up in an
electrolytic cell that opposes the flow of current, caused by
This terminology is under the jurisdiction of ASTM Committee B08 on
such factors as concentration polarization and electrode
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
films. See emf (electromotive force).
B08.01 on Ancillary Activities.
ball burnishing—See barrel burnishing.
Current edition approved Feb. 10, 2003. Published May 2003. Originally
approved in 1961. Last previous edition approved in 1996 as B 374–96.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B374–96 (2003)
barrel burnishing—the smoothing of surfaces by means of bright-throwing power—the measure of the ability of a
tumbling the work in rotating barrels in the presence of plating solution or a specified set of plating conditions to
metallic or ceramic shot, and in the absence of abrasive. In deposit uniformly bright electroplate upon an irregularly
ball burnishing, the shot consists of hardened steel balls. shaped cathode.
barrel electroplating—an electroplating process in which bronzing—the application of a chemical finish to copper or
electrodeposits are applied to articles in bulk in a rotating, copper alloy surfaces to alter the color.
oscillating, or otherwise moving container. brush plating—a method of plating in which the plating
barrel finishing (or tumbling)—bulk processing in barrels, in solution is applied with a pad or brush, within which is an
either the presence or absence of abrasives or burnishing anode and which is moved over the cathode to be plated.
shot, for the purpose of improving the surface finish. brush polishing (electrolytic)—a method of electropolishing
barrel plating (or cleaning)—platingorcleaninginwhichthe (q.v.) in which the electrolyte is applied with a pad or brush
work is processed in bulk in a rotating container. in contact with the part to be polished.
barrel processing—mechanical, chemical, cleaning, or elec- buffer—a compound or mixture that, when contained in
trolytic treatment of articles in bulk or in a rotating, solution, causes the solution to resist change in pH. Each
oscillating, or otherwise moving container. buffer has a characteristic limited range of pH over which it
barrier layer—in anodizing aluminum, the thin, pore-free, is effective.
semiconducting aluminum oxide region nearest the metal buffing—the smoothing of a surface by means of a rotating
surface and distinct from the main anodic oxide coating flexiblewheeltothesurfaceofwhichfine,abrasiveparticles
which has a pore structure. are applied in liquid suspension, paste, or grease stick form.
base metal—(1) See basis metal;(2) in diffusion coatings, the building up—electroplating for the purpose of increasing the
metal present in the largest proportion in an alloy. dimensions of an article.
basis metal (or material)—material upon which coatings are burn off—the unintentional removal of an autocatalytic de-
deposited. posit from a nonconducting substrate, during subsequent
bipolar electrode—an electrode that is not directly connected electroplating operations, owing to the application of excess
to the power supply but is so placed in the solution between current or a poor contact area.
the anode and the cathode that the part nearest the anode burnishing—the smoothing of surfaces by rubbing, accom-
becomes cathodic and the part nearest the cathode becomes plished chiefly by the movement rather than the removal of
anodic. the surface layer.
black oxide—afinishonmetalproducedbyimmersingametal burnt deposit—a rough, noncoherent or otherwise unsatisfac-
in hot oxidizing salts or salt solutions. tory deposit produced by the application of an excessive
blasting—See sand blasting; grit blasting; wet blasting. current density and usually containing oxides or other
blister—a dome-shaped imperfection or defect, resulting from inclusions.
loss of adhesion between a metallic deposit and the sub- bus (bus bar)—arigidconductingsection,forcarryingcurrent
strate. to the anode and cathode bars.
bloom—a visible exudation or efflorescence on a surface. butler finish—afinishcomposedoffine,uniformlydistributed
blue dip—a solution, once widely used, containing a mercury parallel lines, having a characteristic luster usually produced
compound used to deposit mercury upon a metal by immer- with rotating wire brushes or cloth wheels with applied
sion, usually prior to silver plating. abrasives.
blueing—the formation of a thin oxide film on steel, either by calomel half cell (calomel electrode)— a half cell containing
heating in air, or by immersion in oxidizing solutions. a mercury electrode in contact with a solution of potassium
bright dip (nonelectrolytic)—a solution used to produce a chloride of specified concentration that is saturated with
bright surface on a metal. mercurous chloride (calomel).
bright electroplating—a process that produces an electrode- calorizing—imparting resistance to oxidation to an iron or
posit having a high degree of specular reflectance in the steel surface by heating in aluminum powder at 800 to
as-plated condition. 1000°C (1470 to 1830°F).
bright electroplating range—the range of current densities CASS test (copper accelerated salt spray)— an accelerated
within which an electroplating solution produces a bright corrosion test for some electrodeposits and for anodic
deposit under a given set of operating conditions. coatings on aluminum (see Test Method B368 ).
bright plating—a process that produces an electrodeposit cataphoresis—See electrophoresis.
having a high degree of specular reflectance in the as-plated cathode—the electrode in electrolysis at which positive ions
condition. are discharged, negative ions are formed, or other reducing
bright plating range—the range of current densities within actions occur.
which a given plating solution produces a bright plate.
brightener—an addition agent that leads to the formation of a
bright plate, or that improves the brightness of the deposit. Annual Book of ASTM Standards, Vol 02.05.
B374–96 (2003)
cathode efficiency—the current efficiency of a specified ca- ultrasonic cleaning—cleaning by any chemical means aided
thodic process. by ultrasonic energy.
cathode film—thelayerofsolutionincontactwiththecathode cleaning-emulsifiable solvent—two-stage cleaning system
that differs in composition from that of the bulk of the wherein a concentrate containing organic solvents and
solution. surface-active agents is applied to a surface, subsequently
cathode polarization— See polarization. emulsified, and removed along with the soil, by water
catholyte—the portion of the electrolyte in the vicinity of the rinsing.
cathode; in a divided cell the portion of the cathode side of coating cycle—specific time and temperature to achieve de-
the diaphragm. sired depth of diffusion.
cation—a positively-charged ion. coating, diffusion—an alloy coating produced by applying
caustic dip—in diffusion coatings, a strongly alkaline treat- heat to one or more coatings deposited on a metal substrate.
ment applied by dip or spray for neutralizing acid residues. colloidal particle—an electrically-charged particle, generally
cementation—See pack cementation. smaller in size than 200 mµ, dispersed in a second continu-
chelate compound—a compound in which the metal is con- ous phase.
tainedasanintegralpartofaringstructureandisnotreadily color anodizing—in anodizing aluminum, formation of a
ionized. colored coating on aluminum where the colored compound,
chelating agent—a compound capable of forming a chelate pigment, or dye is incorporated after the coating has been
compound with a metal ion. See chelate compound. formed.
chemical milling—the shaping of a work piece by immersion coloring—(1) the production of desired colors on metal
in an etchant employing a resist for selective removal of surfaces by appropriate chemical or electrochemical action.
material.
(2) light buffing of metal surfaces for the purpose of
chemical plating—deposition of a metal coating by chemical,
producing a high luster. Called “color buffing.”
non-electrolytic methods. See also immersion plate, con-
complex ion—an ion composed of two or more ions or
tact plating.
radicals,bothofwhicharecapableofindependentexistence,
chemical polishing—the improvement in surface smoothing =
for example, cuprocyanide (Cu(CN) ) .
of a metal by simple immersion in a suitable solution. See
complexing agent—a compound that will combine with me-
bright dip (nonelectrolytic).
tallic ions to form complex ions. See complex ion.
chromating—the process for producing a conversion coating
composite coating—a coating consisting of deposits incorpo-
(q.v.) containing chromium compounds.
rating particles of another material. See also dispersion
chromizing—a surface treatment at elevated temperatures,
coating.
generally carried out in pack, vapor, or salt baths, in which
composite plate—an electrodeposit consisting of two or more
an alloy is formed by the inward diffusion of chromium into
layers of metal deposited successively.
the base metal.
concentration polarization—thatpartofthetotalpolarization
cleaning—the removal of grease, oxides, or other foreign
that is caused by changes in the activity of the potential-
material from a surface.
determining components of the electrolyte.
alkaline cleaning—cleaningbymeansofalkalinesolutions.
conductance—the capacity of a medium, usually expressed in
anodic or reverse cleaning—electrolytic cleaning in which
mhos, for transmitting electric current. The reciprocal of
the work is the anode.
resistance.
cathodic or direct cleaning—electrolytic cleaning in which
conducting salt—a salt added to the solution in order to
the work is the cathode.
increase its conductivity.
diphase cleaning— cleaning by means of solutions that
conductivity—specific conductance—the current transferred
contain a solvent layer and an aqueous layer. Cleaning is
across unit area per unit potential gradient. In the metric
effected both by solvent and emulsifying action.
system, K=amperes per square centimetre divided by volts
direct current cleaning—See cathodic or direct cleaning.
per centimetre. The reciprocal of resistivity.
electrolytic cleaning—alkalinecleaninginwhichacurrentis
contact plating—deposition of a metal by the use of an
passed through the solution, the work being one of the
internal source of current by immersion of the work in
electrodes.
solution in contact with another metal.
emulsion cleaning— cleaning by means of solutions con-
contact potential—the potential difference at the junction of
taining organic solvents, water, and emulsifying agents.
two dissimilar substances.
immersion—See soak cleaning.
reverse current
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