ASTM B343-92a(2004)e1
(Practice)Standard Practice for Preparation of Nickel for Electroplating with Nickel
Standard Practice for Preparation of Nickel for Electroplating with Nickel
ABSTRACT
This practice summarizes well-known, generally practical methods for producing adherent electrodeposits of nickel on nickel. The types of nickel for which an overplate of nickel may be desired are dull nickel, semi-bright nickel, bright nickel, and nickel strike. The following cleaning treatments may be used for all conditions and types of electrodeposited nickel: degreasing and electrolytic alkaline cleaning. The procedures should be used for etching or activating the nickel surface are the following: anodic treatment in concentrated sulfuric acid; anodic etching in sulfuric acid; anodic etching in watts-type bath; acid-nickel chloride treatment; etching by acid immersion; electropolishing treatment; and cathodic treatment.
SCOPE
1.1 This practice summarizes well-known, generally practical methods for producing adherent electrodeposits of nickel on nickel.
1.2 Electrodeposits of nickel on nickel are produced, for example, to improve the performance of decorative coatings, to reclaim electroplated parts that are defective, and to resume nickel electroplating after interruptions in processing. Interruptions may be deliberate, for example, to machine the electrodeposit at an intermediate stage in the electrodeposition of thick nickel coatings. The interruptions may be unintentional, for example, resulting from equipment and power failures.
1.3 To ensure good adhesion of nickel to nickel, precautions should be taken to avoid biopolar effects during nickel electroplating. This is of particular importance in return-type automatic plating machines where one rack follows another rack closely. Bipolar effects can be avoided by making the racks cathodic while they are entering or leaving the nickel tank. Separate current control on entry and exit stations is desirable.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Endorsed by American
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Designation:B343–92a(Reapproved 2004) Electroplaters’ Society
Endorsed by National
Association of Metal Finishers
Standard Practice for
Preparation of Nickel for Electroplating with Nickel
This standard is issued under the fixed designation B343; 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.
´ NOTE—Warning note in 4.2 updated in May 2004.
1. Scope 2.2.3 Buffed, polished, or machine-ground surfaces (see
5.3), and
1.1 This practice summarizes well-known, generally practi-
2.2.4 Surfaces that have been given a reverse-current treat-
cal methods for producing adherent electrodeposits of nickel
ment in an alkaline solution for cleaning or possibly stripping
on nickel.
an overplate of chromium (see 5.4).
1.2 Electrodeposits of nickel on nickel are produced, for
example,toimprovetheperformanceofdecorativecoatings,to
3. Cleaning
reclaim electroplated parts that are defective, and to resume
3.1 The following cleaning treatments may be used for all
nickel electroplating after interruptions in processing. Interrup-
conditions and types of electrodeposited nickel. The choice of
tions may be deliberate, for example, to machine the electrode-
the procedure will be governed largely by the condition of the
posit at an intermediate stage in the electrodeposition of thick
surface.
nickel coatings. The interruptions may be unintentional, for
3.1.1 Degreasing—Degreasing is used to remove the bulk
example, resulting from equipment and power failures.
of grease, oil, and buffing compounds that may be present on
1.3 To ensure good adhesion of nickel to nickel, precautions
the surface. The cleaning may be effected with vapor degreas-
should be taken to avoid biopolar effects during nickel elec-
ing, organic solvents, emulsion cleaners, or soak cleaner.
troplating. This is of particular importance in return-type
3.1.2 Electrolytic Alkaline Cleaning—Removal of final
automatic plating machines where one rack follows another
traces of dirt, grease, and oil is accomplished best with
rack closely. Bipolar effects can be avoided by making the
electrolytic alkaline cleaning. The solution may be either a
racks cathodic while they are entering or leaving the nickel
proprietary cleaner or a formulated one. Since a nickel surface
tank. Separate current control on entry and exit stations is
forms an oxide coating if treated anodically in an alkaline
desirable.
solution, this condition must be altered in subsequent steps if it
1.4 This standard does not purport to address all of the
cannot be avoided.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Activating
priate safety and health practices and determine the applica-
4.1 The procedure used for etching or activating the nickel
bility of regulatory limitations prior to use.
surface usually determines the soundness of the adhesion. The
2. Types of Nickel choice of the procedure may be governed by the condition of
the surface and possibly the type of nickel. The milder etching
2.1 Thetypesofnickelforwhichanoverplateofnickelmay
treatment should be used in the case of highly finished
bedesiredaredullnickel,semi-brightnickel,brightnickel,and
surfaces, but it may result in sacrificing maximum adhesion.
nickel strike. Variations in these types may possibly require
The thickness of the nickel may militate against the use of
special handling.
certain etching procedures, and therefore the thickness re-
2.2 Surface conditions of the nickel may vary as follows:
moved is indicated for each procedure described in 4.2 to 4.8.
2.2.1 Freshly electroplated surfaces that are still wet with
4.2 Anodic Treatment in Concentrated Sulfuric Acid—
electroplating solution or rinse water (see 5.1),
(Nickel removed nil). A70 mass % sulfuric acid solution
2.2.2 Freshly electroplated surfaces that have been allowed
containing 661 mL of concentrated, 96 mass % sulfuric acid
to dry (see 5.2),
(density 1.83 mL) diluted to 1 Lmay be used for activating the
nickel surface provided the temperature of the solution is not
This practice is under the jurisdiction of ASTM Committee B08 on Metallic
over 30°C (see Warning). When the initial mixture cools,
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on
dilute to exact volume. The time of treatment should be about
Pre Treatment.
1 min at a current density of 10 A/dm . At this current density
Current edition approved April 1, 2004. Published May 2004. Originally
approved in 1960. Last previous edition approved in 1998 as B343 – 92a (1998).
the nickel normally goes passive and a bright surface becomes
DOI: 10.1520/B0343-92AR04E01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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B343–92a (2004)
only slightly dull. This type of passivity is removed by g/mL) diluted to 1 L. See Warning in 4.2. Temperature of
subsequent rinsing in water. (Warning—Slowly add the sul- solution ranges from 45 to 55°C. The work is made anodic at
furic acid with rapid stirring to the approximate amount of current densities from 15 to 20 A/dm . The electropolishing
water required.) treatment is usually applied for 2 to 15 min. The cathodes may
be electrolytic nickel strip. Subsequent alkaline cleaning and
4.3 Anodic Etching in Sulfuric Acid—(Nickel removed
approximately 1.3 µm.) A25 mass % sulfuric acid solution, an acid dip are normally used before electroplating.
4.8 Cathodic Treatment—(Nickel removed nil.) These pro-
containing 166 mL of concentrated, 96 mass % sulfuric acid
(density 1.83 g/mL), diluted to 1 L is used for this anodic cedures are recommended where the nickel surface has not
been severely passivated. Prior cleaning may be required, such
etching treatment in which the nickel surface is first etched at
a low current density of 2 A/dm for 10 min and then made as alkaline soak cleaning or electrocleaning, or both. If
passive at 20A/dm for 2 min and finally cathodic for 2 or 3 s electrocleaning is employed, only cathodic current should be
at 20 A/dm . See Warning in 4.2. The temperature of the used. In the following formulations, 96 mass % sulfuric acid
solution should be kept below 25°C. This treatment results in with a density of 1.83 g/mL, and 37 mass % hydrochloric acid
excellent adhesion, but the amount of etching makes it less with a density of 1.16 g/mL, are used.
desira
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