ASTM B840-15

Standard Specification for Electrodeposited Coatings of Zinc Cobalt Alloy Deposits

ABSTRACT
This specification covers the requirements for electrodeposited zinc cobalt alloy coatings on metals. The coating class is Class 1 and five coating types are Type a, Type b, Type c, Type d, and Type e. The metal to be plated shall be subjected to such cleaning, pickling, and electroplating procedures. Coating requirements include: substrate, nature of coating, appearance, thickness, adhesion, corrosion resistance, and pre- and post-coating treatments of iron and steel for reducing the risk of hydrogen embrittlement. Adhesion, porosity, corrosion resistance, or appearance tests shall be made.
SCOPE
1.1 This specification covers the requirements for electrodeposited zinc cobalt alloy coatings on metals.  
1.2 The following precautionary caveat pertains to the test method portion only, Section 8, 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: 30-Apr-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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:B840 −15
Standard Specification for
1
Electrodeposited Coatings of Zinc Cobalt Alloy Deposits
This standard is issued under the fixed designation B840; 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.
1. Scope B571Practice for Qualitative Adhesion Testing of Metallic
Coatings
1.1 Thisspecificationcoverstherequirementsforelectrode-
B602Test Method for Attribute Sampling of Metallic and
posited zinc cobalt alloy coatings on metals.
Inorganic Coatings
1.2 The following precautionary caveat pertains to the test
B697Guide for Selection of Sampling Plans for Inspection
method portion only, Section 8, of this specification: This
of Electrodeposited Metallic and Inorganic Coatings
standard does not purport to address all of the safety concerns,
B762Test Method of Variables Sampling of Metallic and
if any, associated with its use. It is the responsibility of the user
Inorganic Coatings
of this standard to establish appropriate safety and health
B849Specification for Pre-Treatments of Iron or Steel for
practices and determine the applicability of regulatory limita-
Reducing Risk of Hydrogen Embrittlement
tions prior to use.
B850GuideforPost-CoatingTreatmentsofSteelforReduc-
ing the Risk of Hydrogen Embrittlement
2. Referenced Documents
D3951Practice for Commercial Packaging
2
2.1 ASTM Standards:
B117Practice for Operating Salt Spray (Fog) Apparatus
3. Terminology
B183Practice for Preparation of Low-Carbon Steel for
3.1 Definitions—Many terms used in this specification are
Electroplating
defined in Terminology B374.
B242Guide for Preparation of High-Carbon Steel for Elec-
3.2 Definitions of Terms Specific to This Standard:
troplating
3.2.1 significant surface, n—that portion of a coated arti-
B320Practice for Preparation of Iron Castings for Electro-
cle’s surface where the coating is required to meet all the
plating
requirements of the coating specification for that article.
B322Guide for Cleaning Metals Prior to Electroplating
Significant surfaces are usually those that are essential to the
B374Terminology Relating to Electroplating
serviceability or function of the article or can be a source of
B487Test Method for Measurement of Metal and Oxide
corrosion products or tarnish films that interfere with the
Coating Thickness by Microscopical Examination of
function or desirable appearance of the article. Significant
Cross Section
surfaces are those surfaces that are identified by the purchaser
B499Test Method for Measurement of CoatingThicknesses
by, for example, indicating them on an engineering drawing of
by the Magnetic Method: Nonmagnetic Coatings on
the product or marking a sample item of the product.
Magnetic Basis Metals
B504Test Method for Measurement of Thickness of Metal-
4. Classification
lic Coatings by the Coulometric Method
4.1 There is one coating class, and it is defined as Class
B507Practice for Design ofArticles to Be Electroplated on
Racks 1—a zinc cobalt alloy that is approximately 99% by mass zinc
and at minimum 0.5% by mass cobalt.
B568Test Method for Measurement of Coating Thickness
by X-Ray Spectrometry
4.2 There are five coating types and they are defined as
follows:
1 4.2.1 Type A—With colorless (blue bright) chromate con-
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatingsand is the direct responsibility of Subcommittee version coatings.
B08.06 on Soft Metals.
4.2.2 Type B—With yellow chromate conversion coating.
Current edition approved May 1, 2015. Published May 2015. Originally
4.2.3 Type C—With bronze chromate conversion coating.
approvedin1993.Lastpreviouseditionapprovedin2009asB840–99(2009).DOI:
4.2.4 Type D—With black chromate conversion coating.
10.1520/B0840-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.2.5 Type E—Anyoftheabovetypesplusorganictopcoat.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on NOTE 1—Whereas colored chromate conversion coatings are usually
the ASTM website. meant to include various shades of yellow to bronze when used with
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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B840−15
non-alloyed zinc, yellow and bronze chromate conversion coatings are
6.3 Appearance:
considered distinctly different when applied to alloyed zinc coatings and
6.3.1 The coating on all readily visible surfaces shall have
are formulated specifically to produce the desired coating.
a
...

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: B840 − 99 (Reapproved 2009) B840 − 15
Standard Specification for
1
Electrodeposited Coatings of Zinc Cobalt Alloy Deposits
This standard is issued under the fixed designation B840; 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 electrodeposited zinc cobalt alloy coatings on metals.
1.2 The following precautionary caveat pertains to the test method portion only, Section 8, 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
2.1 ASTM Standards:
B117 Practice for Operating Salt Spray (Fog) Apparatus
B183 Practice for Preparation of Low-Carbon Steel for Electroplating
B242 Guide for Preparation of High-Carbon Steel for Electroplating
B320 Practice for Preparation of Iron Castings for Electroplating
B322 Guide for Cleaning Metals Prior to Electroplating
B374 Terminology Relating 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
B507 Practice for Design of Articles to Be Electroplated on Racks
B568 Test Method for Measurement of Coating Thickness by X-Ray Spectrometry
B571 Practice for Qualitative Adhesion Testing of Metallic Coatings
B602 Test Method for Attribute Sampling of Metallic and Inorganic Coatings
B697 Guide for Selection of Sampling Plans for Inspection of Electrodeposited Metallic and Inorganic Coatings
B762 Test Method of Variables Sampling of Metallic and Inorganic Coatings
B849 Specification for Pre-Treatments of Iron or Steel for Reducing Risk of Hydrogen Embrittlement
B850 Guide for Post-Coating Treatments of Steel for Reducing the Risk of Hydrogen Embrittlement
D3951 Practice for Commercial Packaging
3. Terminology
3.1 Definitions—Many terms used in this specification are defined in Terminology B374.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 significant surface, n—that portion of a coated article’s surface where the coating is required to meet all the requirements
of the coating specification for that article. Significant surfaces are usually those that are essential to the serviceability or function
of the article or can be a source of corrosion products or tarnish films that interfere with the function or desirable appearance of
the article. Significant surfaces are those surfaces that are identified by the purchaser by, for example, indicating them on an
engineering drawing of the product or marking a sample item of the product.
1
This specification is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatingsand is the direct responsibility of Subcommittee B08.06 on Soft
Metals.
Current edition approved Sept. 1, 2009May 1, 2015. Published December 2009 June 2015. Originally approved in 1993. Last previous edition approved in 20042009 as
B840 – 99(2004).(2009). DOI: 10.1520/B0840-99R09.10.1520/B0840-15.
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 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B840 − 15
4. Classification
4.1 There is one coating class, and it is defined as Class 1—deposits having 99 mass % zinc, the balance being 1—a zinc cobalt
alloy that is approximately 99% by mass zinc and at minimum 0.5% by mass cobalt.
4.2 There are five coating types and they are defined as follows:
4.2.1 Type a—WithA—With colorless (blue bright) chromate conversion coatings.
4.2.2 Type b—WithB—With yellow chromate conversion coating.
4.2.3 Type c—WithC—With bronze chromate conversion coating.
4.2.4 Type d—WithD—With black chromate conv
...