ASTM B579-73(2015)

Standard Specification for Electrodeposited Coatings of Tin-Lead Alloy (Solder Plate)

ABSTRACT
This specification establishes the requirements for mat, bright, and flow-brightened electrodeposited tin-lead alloy coatings on fabricated articles of iron, steel, copper, and copper alloys to protect them against corrosion, to improve and preserve solderability over long periods of storage, and to improve anti-galling characteristics. Sheets, strips, or wires in the unfabricated form, or threaded articles having a specified diameter, are not covered here. The classification notation shall include the type of basis metal, thickness of tin-lead coating required, service condition number indicating the severity of service required, and coating composition. Coatings shall be sampled, tested, and shall conform accordingly to specified requirements as to composition, appearance, thickness, adhesion (to be examined either by burnishing test, quenching test, reflow test, or bend test), and solderability (to be assessed either by non-automated or automated dip test, spread test, globule test, or artificial aging test).
SCOPE
1.1 This specification covers the requirements for electrodeposited tin-lead coatings on fabricated articles of iron, steel, copper, and copper alloys, to protect them against corrosion (Note 1), to improve and preserve solderability over long periods of storage, and to improve anti-galling characteristics.  
Note 1: Some corrosion of tin-lead coatings may be expected in outdoor exposure. In normal indoor exposure, tin-lead is protective on iron, copper, and copper alloys. Corrosion may be expected at discontinuities (pits or pores) in the coating. Porosity decreases as the thickness is increased. A primary use of the tin-lead coating (solder) is with the printed circuit industry as a solderable coating and as an etch mask material.  
1.2 This specification applies to electrodeposited coatings containing a minimum of 50 % and a maximum of 70 % tin. The specification applies to mat, bright, and flow-brightened tin-lead coatings.  
Note 2: Tin-lead plating baths are composed of tin and lead fluoborates and of addition agents to promote stability. The final appearance may be influenced by the addition of proprietary brighteners. Without brighteners, the coatings are mat; with brighteners, they are semibright or bright. Flow-brightened coatings are obtained by heating mat coatings to above the melting point of tin-lead for a few seconds and then quenching; palm oil, hydrogenated oils, or fats are used as a heat-transfer medium at a temperature of 260 ± 10°C (500 ± 20°F), but other methods of heating are also in use. The maximum thickness for flow-brightening is about 7.5 μm (0.3 mil); thicker coatings tend to reflow unevenly. The shape of the part is also a factor; flat surfaces tend to reflow more unevenly than wires or rounded shapes (Note 3).
Note 3: Volatile impurities in tin-lead coatings will cause bubbling and foaming during flow-brightening resulting in voids and roughness. The impurities can arise from plating solution addition agents and from improper rinsing and processing.  
1.3 This specification does not apply to sheet, strip, or wire in the unfabricated form or to threaded articles having basic major diameters up to and including 19 mm (0.75 in.).

General Information

• Status: Historical
• Publication Date: 28-Feb-2015
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.06 - Soft Metals

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: B579 −73 (Reapproved 2015)
Standard Specification for
1
Electrodeposited Coatings of Tin-Lead Alloy (Solder Plate)
This standard is issued under the fixed designation B579; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 Thisspecificationcoverstherequirementsforelectrode-
B183Practice for Preparation of Low-Carbon Steel for
posited tin-lead coatings on fabricated articles of iron, steel,
Electroplating
copper, and copper alloys, to protect them against corrosion
B242Guide for Preparation of High-Carbon Steel for Elec-
(Note 1), to improve and preserve solderability over long
troplating
periods of storage, and to improve anti-galling characteristics.
B281Practice for Preparation of Copper and Copper-Base
Alloys for Electroplating and Conversion Coatings
NOTE 1—Some corrosion of tin-lead coatings may be expected in
outdoor exposure. In normal indoor exposure, tin-lead is protective on
B322Guide for Cleaning Metals Prior to Electroplating
iron, copper, and copper alloys. Corrosion may be expected at disconti-
B487Test Method for Measurement of Metal and Oxide
nuities(pitsorpores)inthecoating.Porositydecreasesasthethicknessis
Coating Thickness by Microscopical Examination of
increased.Aprimaryuseofthetin-leadcoating(solder)iswiththeprinted
Cross Section
circuit industry as a solderable coating and as an etch mask material.
B499Test Method for Measurement of CoatingThicknesses
1.2 This specification applies to electrodeposited coatings
by the Magnetic Method: Nonmagnetic Coatings on
containing a minimum of 50% and a maximum of 70% tin.
Magnetic Basis Metals
The specification applies to mat, bright, and flow-brightened B504Test Method for Measurement of Thickness of Metal-
tin-lead coatings. lic Coatings by the Coulometric Method
B567Test Method for Measurement of Coating Thickness
NOTE 2—Tin-lead plating baths are composed of tin and lead fluobo-
by the Beta Backscatter Method
ratesandofadditionagentstopromotestability.Thefinalappearancemay
B568Test Method for Measurement of Coating Thickness
be influenced by the addition of proprietary brighteners. Without
by X-Ray Spectrometry
brighteners, the coatings are mat; with brighteners, they are semibright or
E105Practice for Probability Sampling of Materials
bright. Flow-brightened coatings are obtained by heating mat coatings to
abovethemeltingpointoftin-leadforafewsecondsandthenquenching; E122PracticeforCalculatingSampleSizetoEstimate,With
palm oil, hydrogenated oils, or fats are used as a heat-transfer medium at
Specified Precision, the Average for a Characteristic of a
a temperature of 260 6 10°C (500 6 20°F), but other methods of heating
Lot or Process
are also in use. The maximum thickness for flow-brightening is about 7.5
2.2 Other Standards:
µm (0.3 mil); thicker coatings tend to reflow unevenly. The shape of the
MIL-STD-105 Sampling Procedures and Tables for Inspec-
part is also a factor; flat surfaces tend to reflow more unevenly than wires
3
tion by Attributes
or rounded shapes (Note 3).
MIL-STD-414Sampling Procedures and Tables for Inspec-
NOTE 3—Volatile impurities in tin-lead coatings will cause bubbling
3
and foaming during flow-brightening resulting in voids and roughness. tion by Variables for Percent Defective
The impurities can arise from plating solution addition agents and from
improper rinsing and processing. 3. Classification and Service Condition
3.1 Orders for articles to be plated in accordance with this
1.3 This specification does not apply to sheet, strip, or wire
specificationshallspecify,inadditiontotheASTMdesignation
in the unfabricated form or to threaded articles having basic
number and year of issue, the classification notation indicating
major diameters up to and including 19 mm (0.75 in.).
the basis metal and thickness of tin-lead coating required, or
1 2
This specification is under the jurisdiction of ASTM Committee B08 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
B08.06 on Soft Metals. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved March 1, 2015. Published April 2015. Originally the ASTM website.
3
approvedin1973.Lastpreviouseditionapprovedin2009asB579–73(2009).DOI: AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
10.1520/B0579-73R
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B579 − 73 (Reapproved 2009) B579 − 73 (Reapproved 2015)
Standard Specification for
1
Electrodeposited Coatings of Tin-Lead Alloy (Solder Plate)
This standard is issued under the fixed designation B579; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This specification covers the requirements for electrodeposited tin-lead coatings on fabricated articles of iron, steel, copper,
and copper alloys, to protect them against corrosion (Note 1), to improve and preserve solderability over long periods of storage,
and to improve anti-galling characteristics.
NOTE 1—Some corrosion of tin-lead coatings may be expected in outdoor exposure. In normal indoor exposure, tin-lead is protective on iron, copper,
and copper alloys. Corrosion may be expected at discontinuities (pits or pores) in the coating. Porosity decreases as the thickness is increased. A primary
use of the tin-lead coating (solder) is with the printed circuit industry as a solderable coating and as an etch mask material.
1.2 This specification applies to electrodeposited coatings containing a minimum of 50 % and a maximum of 70 % tin. The
specification applies to mat, bright, and flow-brightened tin-lead coatings.
NOTE 2—Tin-lead plating baths are composed of tin and lead fluoborates and of addition agents to promote stability. The final appearance may be
influenced by the addition of proprietary brighteners. Without brighteners, the coatings are mat; with brighteners, they are semibright or bright.
Flow-brightened coatings are obtained by heating mat coatings to above the melting point of tin-lead for a few seconds and then quenching; palm oil,
hydrogenated oils, or fats are used as a heat-transfer medium at a temperature of 260 6 10°C (500 6 20°F), but other methods of heating are also in
use. The maximum thickness for flow-brightening is about 7.5 μm (0.3 mil); thicker coatings tend to reflow unevenly. The shape of the part is also a factor;
flat surfaces tend to reflow more unevenly than wires or rounded shapes (Note 3).
NOTE 3—Volatile impurities in tin-lead coatings will cause bubbling and foaming during flow-brightening resulting in voids and roughness. The
impurities can arise from plating solution addition agents and from improper rinsing and processing.
1.3 This specification does not apply to sheet, strip, or wire in the unfabricated form or to threaded articles having basic major
diameters up to and including 19 mm (0.75 in.).
2. Referenced Documents
2
2.1 ASTM Standards:
B183 Practice for Preparation of Low-Carbon Steel for Electroplating
B242 Guide for Preparation of High-Carbon Steel for Electroplating
B281 Practice for Preparation of Copper and Copper-Base Alloys for Electroplating and Conversion Coatings
B322 Guide for Cleaning Metals Prior to Electroplating
B487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section
B499 Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis
Metals
B504 Test Method for Measurement of Thickness of Metallic Coatings by the Coulometric Method
B567 Test Method for Measurement of Coating Thickness by the Beta Backscatter Method
B568 Test Method for Measurement of Coating Thickness by X-Ray Spectrometry
E105 Practice for Probability Sampling of Materials
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
1
This specification is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.06 on Soft
Metals.
Current edition approved Sept. 1, 2009March 1, 2015. Published November 2009April 2015. Originally approved in 1973. Last previous edition approved in 20042009
as B579–73 (2004).–73 (2009). DOI: 10.1520/B0579-73R09.10.1520/B0579-73R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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 19
...