ASTM B604-91(2015)

Standard Specification for Decorative Electroplated Coatings of Copper Plus Nickel Plus Chromium on Plastics

ABSTRACT
This specification establishes the requirements for several grades and types of electrodeposited copper plus nickel plus chromium coatings on plateable plastic substrates where appearance, durability and resistance to thermal cycling are important to service performance. The coatings covered here are applied subsequent to the application of metal film by autocatalytic deposition or of any strike coatings after autocatalytic deposition. Each coating shall be designated a classification code, which comprises of the following numbers and symbols: service condition number, which indicates the severity of exposure for which the coating is intended; coating classification number, which contains the chemical symbol of each metallic element that comprises the coating, and their corresponding thickness; and symbols for expressing the type of coating. The coatings shall be sampled, tested, and conform to specified requirements as to appearance (visual defects), ductility, minimum thickness (inspected either by coulometric, microscopical, or beta backscatter methods), corrosion and thermal cycling resistance, adhesion, sulfur content, density, and discontinuities.
SCOPE
1.1 This specification covers the requirements for several grades and types of electrodeposited copper plus nickel plus chromium coatings on plateable plastic substrates where appearance, durability and resistance to thermal cycling are important to service performance. Five grades of coatings are provided to correlate with the service conditions under which each is expected to provide satisfactory performance.  
1.2 This specification covers the requirements for coatings applied subsequent to the application of metal film by autocatalytic deposition or subsequent to the application of any strike coatings after autocatalytic deposition.  
1.3 The following caveat pertains only to the test method portions of Section 6, Annex A1, and Appendix X2, Appendix X3, and Appendix X4 of this specification. 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.

General Information

• Status: Historical
• Publication Date: 28-Feb-2015
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.05 - Decorative Coatings

Relations

• Replaces: ASTM B604-91(2008) - Standard Specification for Decorative Electroplated Coatings of Copper Plus Nickel Plus Chromium on Plastics
• Effective Date: 01-Mar-2015
• Replaced By: ASTM B604-91(2019) - Standard Specification for Decorative Electroplated Coatings of Copper Plus Nickel Plus Chromium on Plastics
• Effective Date: 01-Oct-2019
• Referred By: ASTM B380-97(2023) - Standard Test Method for Corrosion Testing of Decorative Electrodeposited Coatings by the Corrodkote Procedure
• Effective Date: 01-Mar-2015
• Referred By: ASTM B456-17(2022) - Standard Specification for Electrodeposited Coatings of Copper Plus Nickel Plus<brk/> Chromium and Nickel Plus Chromium
• Effective Date: 01-Mar-2015
• Referred By: ASTM B368-21 - Standard Test Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test)
• Effective Date: 01-Mar-2015
• Referred By: ASTM B727-04(2020) - Standard Practice for Preparation of Plastics Materials for Electroplating
• Effective Date: 01-Mar-2015

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:B604 −91 (Reapproved 2015)
Standard Specification for
Decorative Electroplated Coatings of Copper Plus Nickel
Plus Chromium on Plastics
This standard is issued under the fixed designation B604; 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 lic Coatings by the Coulometric Method
B530 Test Method for Measurement of Coating Thicknesses
1.1 This specification covers the requirements for several
by the Magnetic Method: Electrodeposited Nickel Coat-
grades and types of electrodeposited copper plus nickel plus
ings on Magnetic and Nonmagnetic Substrates
chromium coatings on plateable plastic substrates where
B532 Specification for Appearance of Electroplated Plastic
appearance, durability and resistance to thermal cycling are
Surfaces
important to service performance. Five grades of coatings are
B533 Test Method for Peel Strength of Metal Electroplated
provided to correlate with the service conditions under which
Plastics
each is expected to provide satisfactory performance.
B556 Guide for Measurement of Thin Chromium Coatings
1.2 This specification covers the requirements for coatings
by Spot Test
applied subsequent to the application of metal film by auto-
B567 Test Method for Measurement of Coating Thickness
catalytic deposition or subsequent to the application of any
by the Beta Backscatter Method
strike coatings after autocatalytic deposition.
B568 Test Method for Measurement of Coating Thickness
1.3 The following caveat pertains only to the test method by X-Ray Spectrometry
portions of Section 6, AnnexA1, and Appendix X2, Appendix
B602 Test Method for Attribute Sampling of Metallic and
X3, and Appendix X4 of this specification. This standard does Inorganic Coatings
not purport to address all of the safety concerns, if any,
B659 Guide for Measuring Thickness of Metallic and Inor-
associated with its use. It is the responsibility of the user of this ganic Coatings
standard to establish appropriate safety and health practices
B727 Practice for Preparation of Plastics Materials for Elec-
and determine the applicability of regulatory limitations prior troplating
to use.
B764 Test Method for Simultaneous Thickness and Elec-
trode Potential Determination of Individual Layers in
2. Referenced Documents
Multilayer Nickel Deposit (STEP Test)
D1193 Specification for Reagent Water
2.1 ASTM Standards:
E50 Practices for Apparatus, Reagents, and Safety Consid-
B368 Test Method for Copper-Accelerated Acetic Acid-Salt
erations for Chemical Analysis of Metals, Ores, and
Spray (Fog) Testing (CASS Test)
Related Materials
B487 Test Method for Measurement of Metal and Oxide
Coating Thickness by Microscopical Examination of
3. Terminology
Cross Section
3.1 Definitions:
B489 Practice for Bend Test for Ductility of Electrodepos-
3.1.1 significant surfaces—those surfaces normally visible
ited and Autocatalytically Deposited Metal Coatings on
(directlyorbyreflection)thatareessentialtotheappearanceor
Metals
serviceability of the article when assembled in normal position
B504 Test Method for Measurement of Thickness of Metal-
or that can be the source of corrosion products that deface
visible surfaces on the assembled article.
This specification is under the jurisdiction of ASTM Committee B08 on
4. Classification
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
B08.05 on Decorative Coatings.
4.1 Five grades of coatings designated by service condition
Current edition approved March 1, 2015. Published April 2015. Originally
numbers and several types of coatings defined by classification
approved in 1975. Last previous edition approved in 2008 as B604 – 91 (2008).
numbers are covered by this specification.
DOI: 10.1520/B0604-91R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.2 Service Condition Number:
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4.2.1 The service condition number indicates the severity of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. exposure for which the grade of coating is intended, in
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B604−91 (2015)
accordance with the following scale: 5. Ordering Information
SC5—extended very severe
5.1 Whenorderingarticlestobeelectroplatedinaccordance
SC4—very severe
with this standard, the purchaser shall state the following:
SC3—severe
5.1.1 ASTM designation number.
SC2—moderate
5.1.2 Either the classification number of the specific coating
SC1—mild
required (see 4.3) or the substrate material and the service
4.2.2 Service condition numbers are further defined in
condition number denoting the severity of the conditions it is
AppendixX1wheretheyarerelatedtotheseverityofexposure
required to withstand (see 4.2). If the service condition number
encountered by electroplated articles.
isquotedandnottheclassificationnumber,themanufactureris
4.3 Coating Classification Number— The coating classifi- free to supply any of the types of coatings designated by the
cation number is a means of specifying the types and thick- classification number corresponding to the service condition
nesses of coatings appropriate for each grade and is comprised number, as given in Table 1. On request, the manufacturer
of the following: shall inform the purchaser of the classification number of the
4.3.1 The symbol for the substrate (PL) indicating it is coating applied.
plateable plastic, followed by a slash mark, 5.1.3 The appearance required, for example, bright, dull, or
4.3.2 The chemical symbol for copper (Cu), satin. Alternatively, samples showing the required finish or
4.3.3 Anumbergivingtheminimumthicknessofthecopper range of finish shall be supplied or approved by the purchaser.
coating in micrometres, 5.1.4 The significant surfaces, to be indicated on drawings
4.3.4 A lower-case letter designating the type of copper of the parts, or by the provision of suitably marked specimens
electrodeposit (see 4.4 and 6.3.1), (see 3.1).
4.3.5 The chemical symbol for nickel (Ni), 5.1.5 The positions on significant surfaces for rack or
4.3.6 Anumber giving the minimum thickness of the nickel contact marks, where such marks are unavoidable (see 6.1.1).
in micrometres, 5.1.6 The extent to which defects shall be tolerated on
4.3.7 A lower-case letter designating the type of nickel nonsignificant surfaces.
electrodeposit (see 4.4 and 6.3.2), 5.1.7 The ductility if other than the standard value (see 6.4).
4.3.8 The chemical symbol for chromium (Cr), and 5.1.8 The extent of tolerable surface deterioration after
4.3.9 A lower-case letter or letters designating the type of corrosion testing (see 6.6.3).
chromium (see 4.4 and 6.3.3). 5.1.9 Sampling methods and acceptance levels (See Section
7).
4.4 Symbols for Expressing Classification—The following
5.1.10 Whether thermal cycle and corrosion testing shall be
lower-case letters shall be used in coating classification num-
conducted individually on separate specimens as described in
bers to describe the types of coatings:
6.6 and 6.7, or sequentially using the same specimens as
a — ductile copper deposited from acid-type baths
described in 6.8, and whether the specimens shall be un-
b — single-layer nickel deposited in the fully-bright condition
d — double- or triple-layer nickel coatings mounted or mounted in a manner simulating assembly when
r — regular (that is, conventional) chromium
these tests are conducted.
mc — microcracked chromium
mp — microporous chromium
5.2 The minimum values of the electrochemical potential
differences between individual nickel layers as measured in
4.5 Example of Complete Classification Number—Acoating
accordance with Test Method B764 within the limits given in
onplasticcomprising15µmminimumductileacidcopperplus
6.10.
15 µm minimum double-layer nickel plus 0.25 µm minimum
microporous chromium has the classification number: PL/
Cu15a Ni15d Cr mp. 6. Product Requirements
6.1 Visual Defects:
TABLE 1 Copper Plus Nickel Plus Chromium Coatings on
6.1.1 The significant surfaces of the electroplated articles
A
Plastic
shall be free of visible defects, such as blisters, pits, roughness,
Service
Equivalent Nickel Thickness
cracks, and uncoated areas, and shall not be stained or
Condition Classification Number
µm mils (approx.)
Number discolored. On articles where a visible contact mark is
SC 5 PL/Cu15a Ni30d Cr mc 30 1.2 unavoidable, its position shall be specified by the purchaser.
PL/Cu15a Ni30d Cr mp 30 1.2
The electroplated article shall be free of damage and clean.
SC 4 PL/Cu15a Ni30d Cr r 30 1.2
6.1.2 Defects in the surface of the molded plastic, such as
PL/Cu15a Ni25d Cr mc 25 1.0
PL/Cu15a Ni25d Cr mp 25 1.0 cold shots, ejection marks, flash, gate marks, parting lines,
SC 3 PL/Cu15a Ni25d Cr r 25 1.0
splay and others, may adversely affect the appearance and
PL/Cu15a Ni20d Cr mc 20 0.8
performance of coatings applied thereto despite the observance
PL/Cu15a Ni20d Cr mp 20 0.8
SC 2 PL/Cu15a Ni15b Cr r 15 0.6
PL/Cu15a Ni10b Cr mc 10 0.4
PL/Cu15a Ni10b Cr mp 10 0.4
SC 1 PL/Cu15a Ni7b Cr r 7 0.3 3
“Performance of Decorative Electrodeposited Copper-Nickel-Chromium Coat-
A
ings on Plastics” is a final report on programs conducted by ASTM and ASEP to
The minimum copper thickness may be greater in some applications to meet
evaluate the coating classification numbers. A copy of the report has been filed at
thermal cycling and other requirements.
ASTM Headquarters as RR B-8-1003.
B604−91 (2015)
in electrodeposited nickel.
of the best electroplating practice.Accordingly, the electroplat-
NOTE 3—It will usually be possible to identify the type of nickel by
er’s responsibility for defects in the coating resulting from the
microscopical examination of the polished and etched section of an article
plastic-molding operation shall be waived (Note 1).
prepared in accordance with Test Method B487. The thickness of the
individual nickel layers in double-layer and triple-layer coatings, as well
NOTE1—Tominimizeproblemsofthistype,thespecificationscovering
as the electrochemical relationships between the individual layers can be
the items to be electroplated should contain appropriate limitations on the
measured by the STEP test in accordance with Test Method B764.
extentofsurfacedefects.PracticeB532distinguishesbetweendefectsthat
ariseprimarilyinmoldingandthosethatariseinelectroplatingoperations.
6.4 Ductility—The minimum value of the ductility shall be
8 % for copper and for nickel when tested by the method given
6.2 Pretreatments—Proper preparatory procedures are es-
sential for satisfactory performance of electrodeposited coat- in Appendix X3. Greater ductility may be requested but shall
be subject to agreement between the purchaser and the manu-
ings on plastics. Procedures described in PracticeB727 may be
followed. In the case of patented processes, the instructions facturer.
provided by the suppliers of those processes shall be followed.
6.5 Coating Thickness:
6.3 Process and Coating Requirements—Following prepa- 6.5.1 The minimum coating thickness shall be as designated
ratory operations, plastic articles are placed in electroplating by the coating classification number.
solutions as required to produce the composite coating de- 6.5.2 Itisrecognizedthatrequirementsmayexistforthicker
scribed by the specific coating classification number or by coatings than are covered by this specification.
coating one of the specified classification numbers listed in 6.5.3 The thickness of a coating and its various layers shall
Table 1 appropriate for the specified service condition number. be measured at points on the significant surfaces (see 4.2 and
6.3.1 Type of Copper—Ductile copper shall be deposited Note 4.)
from acid-type baths containing organic additives that promote
NOTE 4—When significant surfaces are involved on which the specified
leveling by the copper deposit.
thickness of deposit cannot readily be controlled, such as threads, holes,
6.3.2 Type of Nickel—For double- or triple-layer nickel
deep recesses, bases of angles, and similar areas, the purchaser and the
manufacturer should recognize the necessity for either thicker deposits on
coatings, the bottom layer shall contain less than 0.005 mass %
the more accessible surfaces or for special racking. Special racks may
sulfur (Note 2). The top layer shall contain greater than 0.04
involve the use of conforming, auxiliary, or bipolar electrodes, or
mass % sulfur (Note 3), and its thickness shall be not less than
nonconducting shields.
10 % of the total nickel thickness. In double-layer coatings, the
6.5.3.1 The coulometric method described in Test Method
thickness of the bottom layer shall be not less than 60 % of the
B504 may be used to measure thickness of the chromium, the
total nickel thickness. In triple-layer coatings, the bottom layer
total thickness of the nickel, and the thickness of the copper.
shall be not less than 50 % nor more than 70 %. If there are
The STEP test, Test Method B764, which is similar to the
three layers, the intermediate layer shall contain not less than
coulometric method, may be used to determine the thicknesses
0.15 mass % sulfur and shall not exceed 10 % of the total
of individual layers of nickel in a multilayer coating.
nickel thickness. These requirements for multilayer nickel
6.5.3.2 The microscopical method described inTest Method
coatings are summarized in Table 2.
B487 may be used to measure the thickness of each nickel
6.3.3 Thickness of Chromium Deposit—The minimum per-
layer and of the copper layer.
missiblethicknessofthechromiumdepositshallbe0.25µmon
6.5.3.3 The beta backscatter method described in Test
significant surfaces. The thickness of chromium is designated
Method B567 may be used when the total thickness of a
bythesamesymbolasthetypeinsteadofbynumeralsasinthe
copper/nickel/chromium composite coating is to be measured,
case of copper and nickel (see 4.4).
withoutanyindicationofthethicknessofeachindividuallayer.
NOTE 2—The sulfur content is specified in order to indicate which type
6.5.3.4 Other methods may be used if it can be demon-
ofnickelelectroplatingsolutionmustbeused.Althoughnosimplemethod
strated that the uncertainty of the measurement is less than
is yet available for determining the sulfur content of a nickel deposit on a
10 %, or less than that of any applicable method mentioned in
coated article, chemical determinations are possible using specially
...

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: B604 − 91 (Reapproved 2008) B604 − 91 (Reapproved 2015)
Standard Specification for
Decorative Electroplated Coatings of Copper Plus Nickel
Plus Chromium on Plastics
This standard is issued under the fixed designation B604; 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
1.1 This specification covers the requirements for several grades and types of electrodeposited copper plus nickel plus
chromium coatings on plateable plastic substrates where appearance, durability and resistance to thermal cycling are important to
service performance. Five grades of coatings are provided to correlate with the service conditions under which each is expected
to provide satisfactory performance.
1.2 This specification covers the requirements for coatings applied subsequent to the application of metal film by autocatalytic
deposition or subsequent to the application of any strike coatings after autocatalytic deposition.
1.3 The following caveat pertains only to the test method portions of Section 6, Annex A1, and Appendix X2, Appendix X3,
and Appendix X4 of this specification.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.
2. Referenced Documents
2.1 ASTM Standards:
B368 Test Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test)
B487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section
B489 Practice for Bend Test for Ductility of Electrodeposited and Autocatalytically Deposited Metal Coatings on Metals
B504 Test Method for Measurement of Thickness of Metallic Coatings by the Coulometric Method
B530 Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Electrodeposited Nickel Coatings on
Magnetic and Nonmagnetic Substrates
B532 Specification for Appearance of Electroplated Plastic Surfaces
B533 Test Method for Peel Strength of Metal Electroplated Plastics
B556 Guide for Measurement of Thin Chromium Coatings by Spot Test
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
B602 Test Method for Attribute Sampling of Metallic and Inorganic Coatings
B659 Guide for Measuring Thickness of Metallic and Inorganic Coatings
B727 Practice for Preparation of Plastics Materials for Electroplating
B764 Test Method for Simultaneous Thickness and Electrode Potential Determination of Individual Layers in Multilayer Nickel
Deposit (STEP Test)
D1193 Specification for Reagent Water
E50 Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
3. Terminology
3.1 Definitions:
This specification is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.05 on
Decorative Coatings.
Current edition approved Aug. 1, 2008March 1, 2015. Published September 2008April 2015. Originally approved in 1975. Last previous edition approved in 20032008
ε1
as B604 – 91 (2003)(2008). . DOI: 10.1520/B0604-91R08.10.1520/B0604-91R15.
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 19428-2959. United States
B604 − 91 (2015)
3.1.1 significant surfaces—those surfaces normally visible (directly or by reflection) that are essential to the appearance or
serviceability of the article when assembled in normal position or that can be the source of corrosion products that deface visible
surfaces on the assembled article.
4. Classification
4.1 Five grades of coatings designated by service condition numbers and several types of coatings defined by classification
numbers are covered by this specification.
4.2 Service Condition Number:
4.2.1 The service condition number indicates the severity of exposure for which the grade of coating is intended, in accordance
with the following scale:
SC5—extended very severe
SC4—very severe
SC3—severe
SC2—moderate
SC1—mild
4.2.2 Service condition numbers are further defined in Appendix X1 where they are related to the severity of exposure
encountered by electroplated articles.
4.3 Coating Classification Number— The coating classification number is a means of specifying the types and thicknesses of
coatings appropriate for each grade and is comprised of the following:
4.3.1 The symbol for the substrate (PL) indicating it is plateable plastic, followed by a slash mark,
4.3.2 The chemical symbol for copper (Cu),
4.3.3 A number giving the minimum thickness of the copper coating in micrometres,
4.3.4 A lower-case letter designating the type of copper electrodeposit (see 4.4 and 6.3.1),
4.3.5 The chemical symbol for nickel (Ni),
4.3.6 A number giving the minimum thickness of the nickel in micrometres,
4.3.7 A lower-case letter designating the type of nickel electrodeposit (see 4.4 and 6.3.2),
4.3.8 The chemical symbol for chromium (Cr), and
4.3.9 A lower-case letter or letters designating the type of chromium (see 4.4 and 6.3.3).
4.4 Symbols for Expressing Classification—The following lower-case letters shall be used in coating classification numbers to
describe the types of coatings:
a — ductile copper deposited from acid-type baths
b — single-layer nickel deposited in the fully-bright condition
d — double- or triple-layer nickel coatings
r — regular (that is, conventional) chromium
mc — microcracked chromium
mp — microporous chromium
4.5 Example of Complete Classification Number—A coating on plastic comprising 15 μm minimum ductile acid copper plus 15
μm minimum double-layer nickel plus 0.25 μm minimum microporous chromium has the classification number: PL/Cu15a Ni15d
Cr mp.
TABLE 1 Copper Plus Nickel Plus Chromium Coatings on
A
Plastic
Service
Equivalent Nickel Thickness
Condition Classification Number
μm mils (approx.)
Number
SC 5 PL/Cu15a Ni30d Cr mc 30 1.2
PL/Cu15a Ni30d Cr mp 30 1.2
SC 4 PL/Cu15a Ni30d Cr r 30 1.2
PL/Cu15a Ni25d Cr mc 25 1.0
PL/Cu15a Ni25d Cr mp 25 1.0
SC 3 PL/Cu15a Ni25d Cr r 25 1.0
PL/Cu15a Ni20d Cr mc 20 0.8
PL/Cu15a Ni20d Cr mp 20 0.8
SC 2 PL/Cu15a Ni15b Cr r 15 0.6
PL/Cu15a Ni10b Cr mc 10 0.4
PL/Cu15a Ni10b Cr mp 10 0.4
SC 1 PL/Cu15a Ni7b Cr r 7 0.3
A
The minimum copper thickness may be greater in some applications to meet
thermal cycling and other requirements.
B604 − 91 (2015)
5. Ordering Information
5.1 When ordering articles to be electroplated in accordance with this standard, the purchaser shall state the following:
5.1.1 ASTM designation number.
5.1.2 Either the classification number of the specific coating required (see 4.3) or the substrate material and the service condition
number denoting the severity of the conditions it is required to withstand (see 4.2). If the service condition number is quoted and
not the classification number, the manufacturer is free to supply any of the types of coatings designated by the classification number
corresponding to the service condition number, as given in Table 1. On request, the manufacturer shall inform the purchaser of
the classification number of the coating applied.
5.1.3 The appearance required, for example, bright, dull, or satin. Alternatively, samples showing the required finish or range
of finish shall be supplied or approved by the purchaser.
5.1.4 The significant surfaces, to be indicated on drawings of the parts, or by the provision of suitably marked specimens (see
3.1).
5.1.5 The positions on significant surfaces for rack or contact marks, where such marks are unavoidable (see 6.1.1).
5.1.6 The extent to which defects shall be tolerated on nonsignificant surfaces.
5.1.7 The ductility if other than the standard value (see 6.4).
5.1.8 The extent of tolerable surface deterioration after corrosion testing (see 6.6.3).
5.1.9 Sampling methods and acceptance levels (See Section 7).
5.1.10 Whether thermal cycle and corrosion testing shall be conducted individually on separate specimens as described in 6.6
and 6.7, or sequentially using the same specimens as described in 6.8, and whether the specimens shall be unmounted or mounted
in a manner simulating assembly when these tests are conducted.
5.2 The minimum values of the electrochemical potential differences between individual nickel layers as measured in
accordance with Test Method B764 within the limits given in 6.10.
6. Product Requirements
6.1 Visual Defects:
6.1.1 The significant surfaces of the electroplated articles shall be free of visible defects, such as blisters, pits, roughness, cracks,
and uncoated areas, and shall not be stained or discolored. On articles where a visible contact mark is unavoidable, its position
shall be specified by the purchaser. The electroplated article shall be free of damage and clean.
6.1.2 Defects in the surface of the molded plastic, such as cold shots, ejection marks, flash, gate marks, parting lines, splay and
others, may adversely affect the appearance and performance of coatings applied thereto despite the observance of the best
electroplating practice. Accordingly, the electroplater’s responsibility for defects in the coating resulting from the plastic-molding
operation shall be waived (Note 1).
NOTE 1—To minimize problems of this type, the specifications covering the items to be electroplated should contain appropriate limitations on the
extent of surface defects. Practice B532 distinguishes between defects that arise primarily in molding and those that arise in electroplating operations.
6.2 Pretreatments—Proper preparatory procedures are essential for satisfactory performance of electrodeposited coatings on
plastics. Procedures described in Practice B727 may be followed. In the case of patented processes, the instructions provided by
the suppliers of those processes shall be followed.
6.3 Process and Coating Requirements—Following preparatory operations, plastic articles are placed in electroplating solutions
as required to produce the composite coating described by the specific coating classification number or by coating one of the
specified classification numbers listed in Table 1 appropriate for the specified service condition number.
6.3.1 Type of Copper—Ductile copper shall be deposited from acid-type baths containing organic additives that promote
leveling by the copper deposit.
6.3.2 Type of Nickel—For double- or triple-layer nickel coatings, the bottom layer shall contain less than 0.005 mass % sulfur
(Note 2). The top layer shall contain greater than 0.04 mass % sulfur (Note 3), and its thickness shall be not less than 10 % of the
total nickel thickness. In double-layer coatings, the thickness of the bottom layer shall be not less than 60 % of the total nickel
thickness. In triple-layer coatings, the bottom layer shall be not less than 50 % nor more than 70 %. If there are three layers, the
intermediate layer shall contain not less than 0.15 mass % sulfur and shall not exceed 10 % of the total nickel thickness. These
requirements for multilayer nickel coatings are summarized in Table 2.
6.3.3 Thickness of Chromium Deposit—The minimum permissible thickness of the chromium deposit shall be 0.25 μm on
significant surfaces. The thickness of chromium is designated by the same symbol as the type instead of by numerals as in the case
of copper and nickel (see 4.4).
NOTE 2—The sulfur content is specified in order to indicate which type of nickel electroplating solution must be used. Although no simple method is
yet available for determining the sulfur content of a nickel deposit on a coated article, chemical determinations are possible using specially prepared test
specimens. See Appendix X2 for the determination of sulfur in electrodeposited nickel.
“Performance of Decorative Electrodeposited Copper-Nickel-Chromium Coatings on Plastics” is a final report on programs conducted by ASTM and ASEP to evaluate
the coating classification numbers. A copy of the report has been filed at ASTM Headquarters as RR B-8-1003.
B604 − 91 (2015)
TABLE 2 Summary of the Requirements for Double- and Triple-
Layer Nickel Coatings
Thickness Relative to Total
Layer Type of Specific
Nickel Thickness
Sulfur Content
Nickel Elongation
Double-Layer Triple-Layer
Bottom(s) 8 % less than equal to or equal to or
0.005 % greater than greater than
50 % 50 %
Middle (high-sulfur . greater than . 10 % max
(b)) 0.15 mass %
Top (b) . greater than equal to or equal to or
0.04 % greater than greater than
40 % 40 %
A B
Test Method Appendix X3 .
A
See Note 2 in the text of this specification.
B
See Note 3 in the text of this specification.
NOTE 3—It will usually be possible to identify the type of nickel by microscopical examination of the polished and etched section of an article prepared
in accordance with Test Method B487. The thickness of the individual nickel layers in double-layer and triple-layer coatings, as well as the
electrochemical relationships between the individual layers can be measured by the STEP test in accordance with Test Method B764.
6.4 Ductility—The minimum value of the ductility shall be 8 % for copper and for nickel when tested by the method given in
Appendix X3. Greater ductility may be requested but shall be subject to agreement between the purchaser and the manufacturer.
6.5 Coating Thickness:
6.5.1 The minimum coating thickness shall be as designated by the coating classification number.
6.5.2 It is recognized that requirements may exist for thicker coatings than are covered by this specification.
6.5.3 The thickness of a coating and its various layers shall be measured at points on the significant surfaces (see 4.2 and Note
4.)
NOTE 4—When significant surfaces are involved on which the specified thickness of deposit cannot readily be controlled, such as threads, holes, deep
recesses, b
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