ASTM B319-91(2020)
(Guide)Standard Guide for Preparation of Lead and Lead Alloys for Electroplating
Standard Guide for Preparation of Lead and Lead Alloys for Electroplating
SIGNIFICANCE AND USE
3.1 The preparation of lead and lead-alloy surfaces for electroplating is often critical to the successful performance of electrodeposited and autocatalytic metallic coatings.
3.2 This standard outlines the process operation procedures and processing solutions required, that lead to satisfactory electrodeposited metallic coatings (including undercoating) on surfaces of lead and lead-alloys.
SCOPE
1.1 This guide provides methods for preparing lead or lead alloy products for the application of electroplated or autocatalytic coatings.
1.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B319 − 91 (Reapproved 2020) Endorsed by American
Electroplaters’ Society
Endorsed by National
Association of Metal Finishers
Standard Guide for
Preparation of Lead and Lead Alloys for Electroplating
This standard is issued under the fixed designation B319; 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.
1. Scope 4. Nature of Lead
4.1 The tensile strength of lead and lead alloys ranges from
1.1 This guide provides methods for preparing lead or lead
15 to 35 MPa (2000 to 5000 psi), therefore, the measured
alloy products for the application of electroplated or autocata-
adhesion of electroplated coatings cannot be greater than these
lytic coatings.
values.
1.2 This standard does not purport to address all of the
4.2 Difficulties in applying high-quality electroplated coat-
safety concerns, if any, associated with its use. It is the
ings to lead are due to the following properties of lead:
responsibility of the user of this standard to establish appro-
4.2.1 The very active chemical nature of lead, leading to the
priate safety, health, and environmental practices and deter-
formation of oxide films in air,
mine the applicability of regulatory limitations prior to use.
4.2.2 The fact that the lead surface will form films of
1.3 This international standard was developed in accor-
insoluble lead salts with most acids used in pickling,
dance with internationally recognized principles on standard-
4.2.3 The ease with which lead diffuses in contact with
ization established in the Decision on Principles for the
nonferrous metals, and
Development of International Standards, Guides and Recom-
4.2.4 The poor resistance to plastic deformation during
mendations issued by the World Trade Organization Technical
polishing.
Barriers to Trade (TBT) Committee.
5. Process Precautions
2. Referenced Documents
5.1 The following process precautions should be observed:
2.1 ASTM Standards:
5.1.1 Precleaning of raw castings is sometimes necessary to
B281 Practice for Preparation of Copper and Copper-Base
remove mold parting compounds, surface oxides, and residues
Alloys for Electroplating and Conversion Coatings
from recessed areas which are never reached by polishing-
wheel or scratch-brush operations (Section 6).
3. Significance and Use
5.1.2 In high-speed type cyanide electroplating solutions,
the initial current density must be controlled and kept low
3.1 The preparation of lead and lead-alloy surfaces for
enough so that no gassing occurs to cause poor adhesion. This
electroplating is often critical to the successful performance of
is revealed as groups of blisters in the high-current-density
electrodeposited and autocatalytic metallic coatings.
areas of the electroplate.
3.2 This standard outlines the process operation procedures
5.1.3 If a strike electroplate is used, it should be thick
and processing solutions required, that lead to satisfactory
enough to prevent the next electroplating solution from attack-
electrodeposited metallic coatings (including undercoating) on
ingthebasislead.Acopperornickelstrike2.5µmthickshould
surfaces of lead and lead-alloys.
be used, but because there are so many variables involved, no
specific recommendations can be made.
5.1.4 Preplates should be of such thickness that complete
This guide is under the jurisdiction of ASTM Committee B08 on Metallic and alloying with the lead does not take place, an occurrence that
Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on Pre
causes poor adhesion of subsequent deposits. This defect is
Treatment.
indicated by blistering after prolonged storage or after an
Current edition approved Nov. 1, 2020. Published December 2020. Originally
accelerated aging test.
approvedin1957.Lastpreviouseditionapprovedin2014asB319 – 91(2014).DOI:
10.1520/B0319-91R20.
5.1.5 Theleadcompoundsformedbytheactionofacidsand
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
alkalies most often used in electroplating are not water soluble.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Caution must be taken to remove or prevent the formation of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. these to eliminate subsequent adhesion failure. Acids that
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B319 − 91 (2020)
cannot be used are sulfuric, hydrochloric, and hydrofluoric. cleaners and ammonia, or wetting agent soaks should be used.
(Acids that can be used are sulfamic and fluoboric.) Alkalies Spray washing with alkaline or solvent-type cleaners may be
should not be high in caustic content. Mild or buffered cleaners used before the electrocleaning cycle instead of soak cleaning.
are preferred in order to minimize attack on the basis lead
9.2 Electrocleaning:
surface.
9.2.1 Cathodic electrocleaning usually is used, especially
5.1.6 Engraving of electroplated finishes on lead cannot be
for decorative bright finishes.Anodic electrocleaning dissolves
performed on deposits over 5 µm thick as the deposit will tear
the lead and is used sometimes in industrial or special
away from the lead at cross cuts. Engine turning by burnishing
applications if stressed or distorted surface layers must be
can be done on any thickness of deposits.
removed to expose the natural understructure.
5.1.7 Polishing and coloring of the deposit must be per-
9.2.2 There are proprietary cleaners designed for special
formed at slow speeds, and with loose or cooled buffs to
conditions;however,acleanermadeupusing23g/Lofsodium
eliminate overheating and flowing of basis metal.
carbonate and 23 g/L of trisodium orthophosphate, anhydrous
operated at 60 to 80 °C with 6 to 8 V with the work cathodic
6. Precleaning
for 30 to 60 s is advantageous. Hand cleaning by mopping and
6.1 Removefinsandpartinglinesbyuseoftrimmingdiesor
brushing is performed, but the trend is away from hand
by scraping, filing, or grinding. Some machining may be done
operations.
at this point, such as drilling holes, or milling or cutting slots,
9.3 Acid Pickle:
groove, flats, or squared surfaces.
9.3.1 An acid pickle of one of the following types is used to
6.2 Clean in alkaline, emulsion type, or other standard
remove all oxide residues and insoluble compounds left from
cleaning material to remove surface materials (5.1.5).
cleaning:
6.3 After rinsing, transfer the parts into one of the following
9.3.1.1 Anaqueoussolutioncontaining120to250mLof48
pickling solutions, the function of which is to remove surface
mass % fluoboric acid diluted to 1 Lused at 20 to 25 °C for 30
oxides, without significant attack on the lead surface.
...
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