ASTM B374-06(2019)

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Designation: B374 − 06 (Reapproved 2011) B374 − 06 (Reapproved 2019) Endorsed by American
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 (´) 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.
1. Referenced Documents
1.1 ASTM Standards:
B368 Test Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test)
2. Terminology
abrasive blasting—a process for cleaning or finishing by means of an abrasive directed at high velocity against the work piece.
activator—in diffusion coatings, a chemical, usually a halide salt, that enters into a reaction with the source or master alloy,
depositing the source on the substrate.
activation—elimination of a passive condition on a surface.
activity (ion)—the ion concentration corrected for deviations from ideal behavior. Concentration multiplied by activity coefficient.
addition agent—a material added in small quantities to a solution to modify its characteristics. It is usually added to a plating
solution for the purpose of modifying the character of a deposit.
adhesion—the attractive force that exists between an electrodeposit and its substrate that can be measured as the force required
to separate an electrodeposit and its substrate.
adhesion, practical, n—the force or work required to detach or remove a coating from the underlayer or substrate; it can be
measured in terms of peel, pull, or shear strength as an experimentally determined quantity.
aluminizing—forming of an aluminum or aluminum alloy coating on a metal by hot dipping, hot spraying, or diffusion.
amorphous—noncrystalline, or devoid of regular structure.
ampere—the current that will deposit silver at the rate of 0.0011180 g/s. Current flowing at the rate of 1 C/s.
−8
angström unit (A˚)—10 cm.
anion—a negatively-charged ion.
anode—the electrode in electrolysis, at which negative ions are discharged, positive ions are formed, or other oxidizing reactions
occur.
anode corrosion—dissolution of anode metal by the electrochemical action in an electrolytic cell.
This terminology is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.01 on
Ancillary Activities.
Current edition approved April 1, 2011Dec. 1, 2019. Published April 2011January 2020. Originally approved in 1961. Last previous edition approved in 20062011 as
B374 – 06.B374 – 06(2011). DOI: 10.1520/B0374-06R10.10.1520/B0374-06R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B374 − 06 (2019)
anode efficiency—current efficiency of a specified anodic process.
anode film—(1) the layer of solution in contact with the anode that differs in composition from that of the bulk of the solution.
(2) The outer layer of the anode itself consisting of oxidation or reaction products of the anode metal.
anode polarization—Seesee polarization.
anodic coating—a protective, decorative, or functional coating, formed by conversion of the surface of a metal in an electrolytic
oxidation process.
anodizing—an electrolytic oxidation process in which the surface of a metal, when anodic, is converted to a coating having
desirable protective, decorative, or functional properties.
anolyte—the portion of electrolyte in the vicinity of the anode; in a divided cell, the portion of electrolyte on the anode side of
the diaphragm.
anti-pitting agent—an addition agent for the specific purpose of preventing gas pits in a deposit.
autocatalytic plating—deposition of a metal coating by a controlled chemical reduction, catalyzed by the metal or alloy being
deposited.
automatic machine (or conveyor)—a machine for mechanically processing parts through treatment cycles, such as cleaning,
anodizing, or plating.
automatic plating: (1) full—plating in which the cathodes are automatically conveyed through successive cleaning and plating
tanks.tanks; (2) semi—plating in which the cathodes are conveyed automatically through only one plating tank.
auxiliary anode—a supplementary anode employed during electrodeposition to achieve a desired thickness distribution of the
deposit.
auxiliary cathode—See thief.
back emf (electromotive force)—the potential set up in an electrolytic cell that opposes the flow of current, caused by such factors
as concentration polarization and electrode films. See emf (electromotive force).
ball burnishing—See barrel burnishing.
barrel burnishing—the smoothing of surfaces by means of tumbling the work in rotating barrels in the presence of metallic or
ceramic shot, and in the absence of abrasive. In ball burnishing, the shot consists of hardened steel balls.
barrel electroplating—an electroplating process in which electrodeposits are applied to articles in bulk in a rotating, oscillating,
or otherwise moving container.
barrel finishing (or tumbling)—bulk processing in barrels, in either the presence or absence of abrasives or burnishing shot, for
the purpose of improving the surface finish.
barrel plating (or cleaning)—plating or cleaning in which the work is processed in bulk in a rotating container.
barrel processing—mechanical, chemical, cleaning, or electrolytic treatment of articles in bulk or in a rotating, oscillating, or
otherwise moving container.
barrier layer—in anodizing aluminum, the thin, pore-free, semiconducting aluminum oxide region nearest the metal surface and
distinct from the main anodic oxide coating which has a pore structure.
base metal—(1) See basis metal; (2) in diffusion coatings, the metal present in the largest proportion in an alloy.
basis metal (or material)—material upon which coatings are deposited.
bipolar electrode—an electrode that is not directly connected to the power supply but is so placed in the solution between the
anode and the cathode that the part nearest the anode becomes cathodic and the part nearest the cathode becomes anodic.
black oxide—a finish on metal produced by immersing a metal in hot oxidizing salts or salt solutions.
blasting—See sand blasting; grit blasting; wet blasting.
blister—a dome-shaped imperfection or defect, resulting from loss of adhesion between a metallic deposit and the substrate.
bloom—a visible exudation or efflorescence on a surface.
blue dip—a solution, once widely used, containing a mercury compound used to deposit mercury upon a metal by immersion,
usually prior to silver plating.
blueing—the formation of a thin oxide film on steel, either by heating in air, or by immersion in oxidizing solutions.
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bright dip (nonelectrolytic)—a solution used to produce a bright surface on a metal.
bright electroplating—a process that produces an electrodeposit having a high degree of specular reflectance in the as-plated
condition.
bright electroplating range—the range of current densities within which an electroplating solution produces a bright deposit
under a given set of operating conditions.
bright plating—a process that produces an electrodeposit having a high degree of specular reflectance in the as-plated condition.
bright plating range—the range of current densities within 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.
bright-throwing power—the measure of the ability of a plating solution or a specified set of plating conditions to deposit
uniformly bright electroplate upon an irregularly shaped cathode.
bronzing—the application of a chemical finish to copper or copper alloy surfaces to alter the color.
brush plating—a method of plating in which the plating solution is applied with a pad or brush, within which is an anode and
which is moved over the cathode to be plated.
brush polishing (electrolytic)—a method of electropolishing (q.v.) in which the electrolyte is applied with a pad or brush in
contact with the part to be polished.
buffer—a compound or mixture that, when contained in solution, causes the solution to resist change in pH. Each buffer has a
characteristic limited range of pH over which it is effective.
buffing—the smoothing of a surface by means of a rotating flexible wheel to the surface of which fine, abrasive particles are
applied in liquid suspension, paste, or grease stick form.
building up—electroplating for the purpose of increasing the dimensions of an article.
burn off—the unintentional removal of an autocatalytic deposit from a nonconducting substrate, during subsequent electroplating
operations, owing to the application of excess current or a poor contact area.
burnishing—the smoothing of surfaces by rubbing, accomplished chiefly by the movement rather than the removal of the surface
layer.
burnt deposit—a rough, noncoherent or otherwise unsatisfactory deposit produced by the application of an excessive current
density and usually containing oxides or other inclusions.
bus (bus bar)—a rigid conducting section, for carrying current to the anode and cathode bars.
butler finish—a finish composed of fine, uniformly distributed parallel lines, having a characteristic luster usually produced with
rotating wire brushes or cloth wheels with applied abrasives.
calomel half cell (calomel electrode)— a half cell containing a mercury electrode in contact with a solution of potassium chloride
of specified concentration that is saturated with mercurous chloride (calomel).
calorizing—imparting resistance to oxidation to an iron or steel surface by heating in aluminum powder at 800 to 1000°C1000 °C
(1470 to 1830°F).1830 °F).
CASS test (copper accelerated salt spray)—an accelerated corrosion test for some electrodeposits and for anodic coatings on
aluminum (see Test Method B368).
cataphoresis—See electrophoresis.
cathode—the electrode in electrolysis at which positive ions are discharged, negative ions are formed, or other reducing actions
occur.
cathode efficiency—the current efficiency of a specified cathodic process.
cathode film—the layer of solution in contact with the cathode that differs in composition from that of the bulk of the solution.
cathode polarization— See see polarization.
catholyte—the portion of the electrolyte in the vicinity of the cathode; in a divided cell, the portion of the cathode side of the
diaphragm.
cation—a positively-charged ion.
caustic dip—in diffusion coatings, a strongly alkaline treatment applied by dip or spray for neutralizing acid residues.
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cementation—See pack cementation.
chelate compound—a compound in which the metal is contained as an integral part of a ring structure and is not readily ionized.
chelating agent—a compound capable of forming a chelate compound with a metal ion. See chelate compound.
chemical milling—the shaping of a work piece by immersion in an etchant employing a resist for selective removal of material.
chemical plating—deposition of a metal coating by chemical, non-electrolytic methods. See also immersion plate,contact
plating.
chemical polishing—the improvement in surface smoothing of a metal by simple immersion in a suitable solution. See bright dip
(nonelectrolytic).
chromating—a process for producing a conversion coating containing chromium compounds.
chromizing—a surface treatment at elevated temperatures, generally carried out in pack, vapor, or salt baths, in which an alloy
is formed by the inward diffusion of chromium into the base metal.
cleaning—the removal of grease, oxides, or other foreign material from a surface.
alkaline cleaning—cleaning by means of alkaline solutions.
anodic or reverse cleaning—electrolytic cleaning in which the work is the anode.
cathodic or direct cleaning—electrolytic cleaning in which the work is the cathode.
diphase cleaning—cleaning by means of solutions that contain a solvent layer and an aqueous layer. Cleaning is effected both
by solvent and emulsifying action.
direct current cleaning—See cathodic or direct cleaning.
electrolytic cleaning—alkaline cleaning in which a current is passed through the solution, the work being one of the electrodes.
emulsion cleaning—cleaning by means of solutions containing organic solvents, water, and emulsifying agents.
immersion—See soak cleaning.
reverse current cleaning—See anodic or reverse cleaning.
soak cleaning—cleaning by immersion without the use of current, usually in alkaline solution.
solvent cleaning—cleaning by means of organic solvents.
spray cleaning—cleaning by means of spraying.
ultrasonic cleaning—cleaning by any chemical means aided by ultrasonic energy.
cleaning-emulsifiable solvent—two-stage cleaning system wherein a concentrate containing organic solvents and surface-active
agents is applied to a surface, subsequently emulsified, and removed along with the soil, by water rinsing.
coating cycle—specific time and temperature to achieve desired depth of diffusion.
coating, diffusion—an alloy coating produced by applying heat to one or more coatings deposited on a metal substrate.
colloidal particle—an electrically-charged particle, generally smaller in size than 200 mμ, dispersed in a second continuous phase.
color anodizing—in anodizing aluminum, formation of a colored coating on aluminum where the colored compound, pigment, or
dye is incorporated after the coating has been formed.
coloring—(1) the production of desired colors on metal surfaces by appropriate chemical or electrochemical action.
(1) the production of desired colors on metal surfaces by appropriate chemical or electrochemical action; (2) light buffing of
metal surfaces for the purpose of producing a high luster. Called “color buffing.”
complex ion—an ion composed of two or more ions or radicals
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