ASTM B734-97
(Specification)Standard Specification for Electrodeposited Copper for Engineering Uses
Standard Specification for Electrodeposited Copper for Engineering Uses
SCOPE
1.1 This specification covers requirements for electrodeposited coatings of copper used for engineering purposes. Examples include surface hardening, heat treatment stop-off, as an underplate for other engineering coatings, for electromagnetic interferences (EMI) shielding in electronic circuitry, and in certain joining operations.
1.2 This specification is not intended for electrodeposited copper when used as a decorative finish, or as an undercoat for other decorative finishes.
1.3 This specification is not intended for electrodeposited copper when used for electroforming.
General Information
Relations
Standards Content (Sample)
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Designation: B 734 – 97
Standard Specification for
Electrodeposited Copper for Engineering Uses
This standard is issued under the fixed designation B 734; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope B 568 Test Method for Measurement of Coating Thickness
by X-Ray Spectrometry
1.1 This specification covers requirements for electrodepos-
B 571 Test Methods for Adhesion of Metallic Coatings
ited coatings of copper used for engineering purposes. Ex-
B 588 Test Method for Measurement of Thickness of Trans-
amples include surface hardening, heat treatment stop-off, as
parent or Opaque Coatings by Double-Beam Interference
an underplate for other engineering coatings, for electromag-
Microscope Technique
netic interferences (EMI) shielding in electronic circuitry, and
B 602 Test Method for Attribute Sampling of Metallic and
in certain joining operations.
Inorganic Coatings
1.2 This specification is not intended for electrodeposited
B 659 Guide for Measuring Thickness of Metallic and
copper when used as a decorative finish, or as an undercoat for
Inorganic Coatings
other decorative finishes.
B 678 Test Method for Solderability of Metallic-Coated
1.3 This specification is not intended for electrodeposited
Products
copper when used for electroforming.
B 697 Guide for Selection of Sampling Plans for Inspection
2. Referenced Documents
of Electrodeposited Metallic and Inorganic Coatings
B 762 Method of Variables Sampling of Metallic and Inor-
2.1 ASTM Standards:
ganic Coatings
B 183 Practice for Preparation of Low-Carbon Steel for
B 765 Guide for Selection of Porosity Tests for Electrode-
Electroplating
posits and Related Metallic Coatings
B 242 Practice for Preparation of High-Carbon Steel for
B 832 Guide for Electroforming with Nickel and Copper
Electroplating
B 849 Specification for Pre-treatments of Iron or Steel for
B 254 Practice for Preparation of and Electroplating on
Reducing Risk of Hydrogen Embrittlement
Stainless Steel
B 850 Specification for Post-Coating Treatments of Iron or
B 320 Practice for Preparation of Iron Castings for Electro-
Steel for Reducing Risk of Hydrogen Embrittlement
plating
B 851 Specification for Automated Controlled Shot Peening
B 322 Practice for Cleaning Metals Prior to Electroplating
of Metallic Articles Prior to Nickel, Auto Catalytic Nickel,
B 374 Terminology Relating to Electroplating
or Chromium Plating, or as a Final Finish
B 487 Test Method for Measurement of Metal and Oxide
D 3951 Practice for Commercial Packaging
Coating Thickness by Microscopical Examination of a
F 519 Method for Mechanical Hydrogen Embrittlement
Cross Section
Testing of Plating Processes and Aircraft Maintenance
B 499 Test Method for Measurement of Coating Thick-
Chemicals
nesses by the Magnetic Method: Nonmagnetic Coatings on
2.2 Military Standard:
Magnetic Basis Metals
MIL-R-81841 Rotary Flap Peening of Metal Parts
B 504 Test Method for Measurement of Thickness of Me-
MIL-S-13165 Shot Peening of Metal Parts
tallic Coatings by the Coulometric Method
MIL-W-81840 Rotary Flap Peening Wheels
B 507 Practice for Design of Articles to Be Electroplated on
Racks
3. Terminology
B 555 Guide for Measurement of Electrodeposited Metallic
2 3.1 Definitions of Terms Specific to This Standard:
Coating Thicknesses by the Dropping Test
3.1.1 significant surfaces—those surfaces normally visible
B 567 Test Method for Measurement of Coating Thickness
2 (directly or by reflection) that are essential to the appearance or
by the Beta Backscatter Method
serviceability of the article when assembled in a normal
position; or which can be the source of corrosion products that
This specification is under the jurisdiction of ASTM Committee B-8 on
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
B08.08.01 on Engineering Coatings.
Current edition approved May 10, 1997. Published Feb. 1998. Originally Annual Book of ASTM Standards, Vol 15.09.
published as B 734 – 84. Last previous edition B 734 – 84 (90). Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 02.05. Robbins Ave., Philadelphia, PA 19111-5094. Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued. NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information. Contact ASTM International (www.astm.org) for the latest information.
B 734
deface visible surfaces on the assembled article. When neces- 6. Coating Requirements
sary, the significant surface shall be indicated on the drawing of
6.1 Appearance—The coating on the significant surfaces of
the article, or by the provision of suitably marked samples.
the product shall be smooth and free of visual defects such as
blisters, pits, roughness, cracks, flaking, burned deposits, and
NOTE 1—When significant surfaces are involved on which the specified
uncoated areas. The boundaries of electroplating that cover
thickness of coating cannot readily be controlled, such as threads, holes,
deep recesses, and bases of angles, it will be necessary to apply thicker only a portion of the surface shall, after finishing as indicated
coatings on the more accessible surfaces, or to use special racking or both.
in the drawing, be free of beads, nodules, jagged edges and
other detrimental irregularities. Imperfections and variations in
3.1.2 inspection lot—a collection of coated articles that; are
appearance in the coating that arise from surface conditions of
of the same type; have been produced to the same specifica-
the basis metal (scratches, pores, roll marks, inclusions, etc.)
tions; have been coated by a single supplier at one time, or at
and that persist in the finish despite the observance of good
approximately the same time, under essentially identical con-
metal finishing practices shall not be cause for rejection.
ditions; and are submitted for acceptance or rejection as a
group.
NOTE 3—Electroplated finishes generally perform better when the
3.2 Definitions—For definitions of the technical terms used substrate over which they are applied is smooth and free of deep scratches,
torn metal, pores, inclusions, and other defects. It is recommended that the
in this specification see Terminology B 374.
specifications covering the unfinished product provide limits for these
defects. A metal finisher can often remove defects through special
4. Classification
treatments such as grinding, polishing, abrasive blasting, and special
4.1 The electrodeposited copper is classified according to
chemical treatments. However, these are not normal treatment steps.
When they are desired, they must be agreed upon between the buyer and
thickness of the electrodeposit in the following table:
the producer.
Class Minimum Thickness, μm
25 25
6.2 Thickness—The thickness of the copper coating on the
20 20
significant surfaces shall conform to the requirements of the
12 12
specified class as defined in Section 4.
x Thickness specified
NOTE 4—Variation in the coating thickness from point-to-point on a
NOTE 2—For electroforming applications, that require much thicker
coated article is an inherent characteristic of electroplating processes.
applications, see Guide B 832.
Therefore, the coating thickness will have to exceed the specified value at
some points on the significant surfaces to ensure that the thickness equals
5. Ordering Information
or exceeds the specified value at all points. As a result, the average coating
thickness on an article will usually be greater than the specified value; how
5.1 The buyer shall supply to the producer in the purchase
much greater is largely determined by the shape of the article (see Practice
order or engineering drawings; marked samples or other
B 507) and the characteristics of the electroplating process. Additionally,
governing documents the following information:
the average coating thickness on an article will vary from article to article
5.1.1 Title, ASTM designation number (Specification
within a production lot. Therefore, if all of the articles in a production lot
B 734), and date of issue.
are to meet the thickness requirement, the average coating thickness of the
production lot as a whole will be greater than the average necessary to
5.1.2 Classification or thickness of electrodeposited copper
ensure that a single article meets the requirements.
(see 4.1),
NOTE 5—When electroplating threaded parts such as machine screws,
5.1.3 Significant surfaces if other than defined in 3.1.1,
care is required to avoid too much plate buildup on the crest of the thread.
5.1.4 Sampling plan (Section 7),
In such applications a maximum plate thickness allowable on the crests
5.1.5 Number of test specimens for destructive testing
may require that thicknesses in other areas be thinner.
(Section 8), and
6.3 Porosity—When specified, the coating shall be suffi-
5.1.6 Thickness, adhesion, solderability, porosity and num-
ciently free of pores to pass the porosity test specified in 8.4.
ber of pores acceptable, or hydrogen embrittlement tests and
6.4 Solderability—When specified, the coating shall meet
methods required (Section 8).
the requirements of Test Method B 678.
5.2 Where required, dimensional tolerances allowed for the
6.5 Pretreatment of Iron and Steel for Reducing the Risk of
specified electroplated copper thickness shall be specified.
Hydrogen Embrittlement—Parts for critical applications that
5.3 In addition to the requirements of 5.1 and when the parts
are made of steels with ultimate tensile strengths of 1000 MPa,
to be electroplated are supplied to the electroplater by the
hardness of 31 HRC or greater, that have been machined,
buyer, the buyer shall also supply the following information as
ground, cold formed, or cold straightened subsequent to heat
required.
treatment, shall require stress relief heat treatment when
5.3.1 Identity of the base material by alloy identification
specified by the purchaser, the tensile strength to be supplied
such as ASTM, AISI, or SAE numbers, or equivalent compo-
by the purchaser. Specification B 849 may be consulted for a
sition information,
list of pretreatments that are used widely.
5.3.2 Hardness of the parts, and
6.6 Post Coating Treatment of Iron and Steel for Reducing
5.3.3 Heat treatment for stress relief, whether it has been
the Risk of Hydrogen Embrittlement—Parts for critical appli-
performed or is required. cations that are made of steels with ultimate tensile strengths of
5.4 If required by either party, the manufacturer of the parts 1000 MPa, hardness of 31 HRC or greater, as well as surface
to be electroplated shall provide the electroplating facility with hardened parts, shall require post coating hydrogen embrittle-
separate test specimens (see section 8.1). ment relief baking when specified by the purchaser, the tensile
NOTICE: This standard has either been superceded and replaced by a new version or discontinued. NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information. Contact ASTM International (www.astm.org) for the latest information.
B 734
NOTE 9—Test specimens often are used to represent the coated articles
strength to be supplied by the purchaser. Specification B 850
in a test if the articles are of a size, shape, or material that is not suitable
may be consulted for a list of post treatments that are used
for the test, or if it is preferred not to submit articles to a destructive test
widely.
because, for example, the articles are expensive or few in number. The
6.7 Peening of Metal Parts—If peening is required before
specimen should duplicate the characteristics of the article that influence
electroplating to induce residual compressive stress to increase
the property being tested.
fatique strength and resistance to stress corrosion cracking of
8.1.1 Special test specimens used to represent articles in an
the metal parts, refer to MIL-S-13165, MIL-R-81841, MIL-W-
adhesion, porosity, corrosion resistance, or appearance test
81840, and Specification B 851.
shall be made of the same material, in the same metallurgical
6.8 Supplementary Requirements:
condition, and have the same surface condition as the articles
6.8.1 Packaging—If packaging requirements are to be met
they represent, and be placed in the production lot of and be
under this specification, they shall be in accordance with
processed along with the articles they represent.
Practice D 3951, or as specified in the contract or order.
8.1.2 Special test specimens used to represent articles in a
NOTE 6—Caution: Some contemporary packaging materials may emit coating thickness test may be made of a material that is suitable
fumes that are deleterious to the surface of the coating.
for the test method even if the represented article is not of the
same material. For example, a low-carbon steel specimen may
7. Sampling
represent a brass article when the magnetic thickness test is
7.1 The sampling plan used for the inspection of a quantity
used (Test Method B 499). The thickness specimen need not be
of the coated articles shall be as agreed upon between the
carried through the complete process with the represented
purchaser and the seller.
article. If not, introduce it into the process at the point where
the coating is applied and carry it through all steps that have a
NOTE 7—Usually, when a collection of coated articles, the inspection
lot (7.2), is examined for compliance with the requirements placed on the bearing on the coating thickness. In rack plating, rack the
articles, a relatively small number of the articles, the sample, is selected at
specimen in the same way with the same distance from and
random and is inspected. The inspection lot then is classified as complying
orientation with the anodes and other items in the process as
or not complying with the requirements based on the results of the
the article it represents.
inspection of the sample. The size of the sample and the criteria of
compliance are determined by the application of statistics. The procedure NOTE
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