ASTM B766-23

Standard Specification for Electrodeposited Coatings of Cadmium

ABSTRACT
This specification covers the requirements for electrodeposited cadmium coatings on products of iron, steel, and other metals. Cadmium coatings are used for corrosion resistance and for corrosion prevention of the basis metal part. The as deposited coating (Type I) is useful for the lowest cost protection in a mild or noncorrosive environment where early formation of white corrosion products is not detrimental or harmful to the function of a component. The prime purpose of the supplementary chromate finishes (Types II and III) on the electroplated cadmium is to increase corrosion resistance.Electrodeposited cadmium coatings shall be classified on the basis of thickness as Class 25, 12, 8, and 5. The coating shall be essentially pure cadmium produced by electrodeposition usually from an alkaline cyanide solution. The basis metal shall be subjected to such cleaning procedures as necessary to ensure a surface satisfactory for subsequent electroplating. Cadmium shall be deposited directly on the basis metal part without an undercoat of another metal except when the part is either stainless steel or aluminum and its alloys. The plating shall be applied after all basis metal heat treatments and mechanical operations. The thickness of the coating everywhere on the significant surface shall conform to the requirements of the specified class. The cadmium coating shall be sufficiently adherent to the basis metal to pass the tests. The supplementary Type II chromate film shall be adherent, nonpowdery, and abrasion resistant. The thickness of electrodeposited cadmium coatings shall be determined by the applicable test methods.
SCOPE
1.1 This specification covers the requirements for electrodeposited cadmium coatings on products of iron, steel, and other metals.  
Note 1: Cadmium is deposited as a coating principally on iron and steel products. It can also be electrodeposited on aluminum, brass, beryllium copper, copper, nickel, and powder metallurgy parts.  
1.2 The coating is provided in various thicknesses up to and including 25 μm either as electrodeposited or with supplementary finishes.  
1.3 Cadmium coatings are used for corrosion resistance and for corrosion prevention of the basis metal part. The as-deposited coating (Type I) is useful for the lowest cost protection in a mild or noncorrosive environment where early formation of white corrosion products is not detrimental or harmful to the function of a component. The prime purpose of the supplementary chromate finishes (Types II and III) on the electroplated cadmium is to increase corrosion resistance. Chromating will retard or prevent the formation of white corrosion products on surfaces exposed to various environmental conditions as well as delay the appearance of corrosion from the basis metal.  
1.4 Cadmium plating is used to minimize bi-metallic corrosion between high-strength steel fasteners and aluminum in the aerospace industry. Undercutting of threads on fastener parts is not necessary as the cadmium coating has a low coefficient of friction that reduces the tightening torque required and allows repetitive dismantling.  
1.5 Cadmium-coated parts can easily be soldered without the use of corrosive fluxes. Cadmium-coated steel parts have a lower electrical contact resistance than zinc-coated steel. The lubricity of cadmium plating is used on springs for doors and latches and for weaving machinery operating in high humidity. Corrosion products formed on cadmium are tightly adherent. Unlike zinc, cadmium does not build up voluminous corrosion products on the surface. This allows for proper functioning during corrosive exposure of moving parts, threaded assemblies, valves, and delicate mechanisms without jamming with debris.  
1.6 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 R...

General Information

• Status: Published
• Publication Date: 30-Apr-2023
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.06 - Soft Metals

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: B766 − 23
Standard Specification for
1
Electrodeposited Coatings of Cadmium
This standard is issued under the fixed designation B766; 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 products on the surface. This allows for proper functioning
during corrosive exposure of moving parts, threaded
1.1 This specification covers the requirements for electrode-
assemblies, valves, and delicate mechanisms without jamming
posited cadmium coatings on products of iron, steel, and other
with debris.
metals.
1.6 This international standard was developed in accor-
NOTE 1—Cadmium is deposited as a coating principally on iron and
dance with internationally recognized principles on standard-
steel products. It can also be electrodeposited on aluminum, brass,
ization established in the Decision on Principles for the
beryllium copper, copper, nickel, and powder metallurgy parts.
Development of International Standards, Guides and Recom-
1.2 The coating is provided in various thicknesses up to and
mendations issued by the World Trade Organization Technical
including 25 μm either as electrodeposited or with supplemen-
Barriers to Trade (TBT) Committee.
tary finishes.
2. Referenced Documents
1.3 Cadmium coatings are used for corrosion resistance and
for corrosion prevention of the basis metal part. The as-
2.1 The following standards form a part of this document to
deposited coating (Type I) is useful for the lowest cost
the extent referenced herein.
protection in a mild or noncorrosive environment where early
2
2.2 ASTM Standards:
formation of white corrosion products is not detrimental or
A165 Specification for Electrodeposited Coatings of Cad-
harmful to the function of a component. The prime purpose of
3
mium on Steel (Withdrawn 1987)
the supplementary chromate finishes (Types II and III) on the
B117 Practice for Operating Salt Spray (Fog) Apparatus
electroplated cadmium is to increase corrosion resistance.
B183 Practice for Preparation of Low-Carbon Steel for
Chromating will retard or prevent the formation of white
Electroplating
corrosion products on surfaces exposed to various environmen-
B201 Practice for Testing Chromate Coatings on Zinc and
tal conditions as well as delay the appearance of corrosion from
Cadmium Surfaces
the basis metal.
B242 Guide for Preparation of High-Carbon Steel for Elec-
1.4 Cadmium plating is used to minimize bi-metallic corro-
troplating
sion between high-strength steel fasteners and aluminum in the
B253 Guide for Preparation of Aluminum Alloys for Elec-
aerospace industry. Undercutting of threads on fastener parts is
troplating
not necessary as the cadmium coating has a low coefficient of
B254 Practice for Preparation of and Electroplating on
friction that reduces the tightening torque required and allows
Stainless Steel
repetitive dismantling.
B281 Practice for Preparation of Copper and Copper-Base
1.5 Cadmium-coated parts can easily be soldered without Alloys for Electroplating and Conversion Coatings
B320 Practice for Preparation of Iron Castings for Electro-
the use of corrosive fluxes. Cadmium-coated steel parts have a
lower electrical contact resistance than zinc-coated steel. The plating
B322 Guide for Cleaning Metals Prior to Electroplating
lubricity of cadmium plating is used on springs for doors and
B343 Practice for Preparation of Nickel for Electroplating
latches and for weaving machinery operating in high humidity.
with Nickel
Corrosion products formed on cadmium are tightly adherent.
B374 Terminology Relating to Electroplating
Unlike zinc, cadmium does not build up voluminous corrosion
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 May 1, 2023. Published May 2023. Originally the ASTM website.
3
approved in 1986. Last previous edition approved in 2015 as B766 – 86 (2015). The last approved version of this historical standard is referenced on
DOI: 10.1520/B0766-23. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700,
...

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: B766 − 86 (Reapproved 2015) B766 − 23
Standard Specification for
1
Electrodeposited Coatings of Cadmium
This standard is issued under the fixed designation B766; 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 cadmium coatings on products of iron, steel, and other metals.
NOTE 1—Cadmium is deposited as a coating principally on iron and steel products. It can also be electrodeposited on aluminum, brass, beryllium copper,
copper, nickel, and powder metallurgy parts.
1.2 The coating is provided in various thicknesses up to and including 25 μm either as electrodeposited or with supplementary
finishes.
1.3 Cadmium coatings are used for corrosion resistance and for corrosion prevention of the basis metal part. The as-deposited
coating (Type I) is useful for the lowest cost protection in a mild or noncorrosive environment where early formation of white
corrosion products is not detrimental or harmful to the function of a component. The prime purpose of the supplementary chromate
finishes (Types II and III) on the electroplated cadmium is to increase corrosion resistance. Chromating will retard or prevent the
formation of white corrosion products on surfaces exposed to various environmental conditions as well as delay the appearance
of corrosion from the basis metal.
1.4 Cadmium plating is used to minimize bi-metallic corrosion between high-strength steel fasteners and aluminum in the
aerospace industry. Undercutting of threads on fastener parts is not necessary as the cadmium coating has a low coefficient of
friction that reduces the tightening torque required and allows repetitive dismantling.
1.5 Cadmium-coated parts can easily be soldered without the use of corrosive fluxes. Cadmium-coated steel parts have a lower
electrical contact resistance than zinc-coated steel. The lubricity of cadmium plating is used on springs for doors and latches and
for weaving machinery operating in high humidity. Corrosion products formed on cadmium are tightly adherent. Unlike zinc,
cadmium does not build up voluminous corrosion products on the surface. This allows for proper functioning during corrosive
exposure of moving parts, threaded assemblies, valves, and delicate mechanisms without jamming with debris.
1.6 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.
2. Referenced Documents
2.1 The following standards form a part of this document to the extent referenced herein.
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 March 1, 2015May 1, 2023. Published April 2015May 2023. Originally approved in 1986. Last previous edition approved in 20082015 as B766 –
86 (2008). DOI: 10.1520/B0766-86R15.(2015). DOI: 10.1520/B0766-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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B766 − 23
2
2.2 ASTM Standards:
3
A165 Specification for Electrodeposited Coatings of Cadmium on Steel (Withdrawn 1987)
B117 Practice for Operating Salt Spray (Fog) Apparatus
B183 Practice for Preparation of Low-Carbon Steel for Electroplating
B201 Practice for Testing Chromate Coatings on Zinc and Cadmium Surfaces
B242 Guide for Preparation of High-Carbon Steel for Electroplating
B253 Guide for Preparation of Aluminum Alloys for Electroplating
B254 Practice for Preparation of and Electroplating on Stainless Steel
B281 Practice for Preparation of Copper and Copper-Base Alloys for Electroplating and Conversion Coatings
B320 Practice for Preparation of Iron Castings for Electroplating
B322 Guide for Cleaning Metals Prior to Electroplating
B343 Practice for Preparation of Nickel for Electroplating with Nickel
B374 Terminology Relating to Electroplating
B487 Test Method for Measur
...