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8/10/2019 B734

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Designation: B 734 ± 97

Standard Speci®cation for Electrodeposited Copper for Engineering Uses

1

This standard is issued under the ®xed 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 ! number in parentheses indicates the year of last reapproval !

superscript epsilon "e# indicates an editorial change since the last revision or reapproval

1. Scope

$$ This speci®cation covers re%uirements for electrodepos&ited coatings of copper used for engineering purposes 'x&

amples

include

surface

hardening,

heat

treatment

stop&off,

as

an underplate for other engineering coatings, for electromag&netic interferences "'()# shielding in electronic circuitry, and in certain *oining operations$+ This speci®cation is not intended for electrodeposited

copper when used as a decorative ®nish, or as an undercoat for other decorative ®nishes$3 This speci®cation is not intended for electrodeposited

copper when used for electroforming

2. Referenced Documents

+$ ASTM Standards:B $3 -ractice for -reparation of .ow&/arbon 0teel for

'lectroplating

+

B +4+ -ractice for -reparation of 1igh&/arbon 0teel for 'lectroplating+

B +24 -ractice for -reparation of and 'lectroplating on 0tainless 0teel+

B 3+ -ractice for -reparation of )ron /astings for 'lectro& plating+

B 3++ -ractice for /leaning (etals -rior to 'lectroplating+

B 374 Terminology elating to 'lectroplating+

B 47 Test (ethod for (easurement of (etal and 5xide/oating Thic6ness by (icroscopical 'xamination of a/ross 0ection+

B 4 Test (ethod for (easurement of /oating Thic6&nesses by the (agnetic (ethod8 9onmagnetic /oatings on

(agnetic

Basis

(etals+

B 24 Test (ethod for (easurement of Thic6ness of (e&tallic /oatings by the /oulometric (ethod+

B 27 -ractice for :esign of!rticles to Be 'lectroplated on ac6s+

B 222 uide for (easurement of 'lectrodeposited (etallic /oating Thic6nesses by the :ropping Test+

B 2<7 Test (ethod for (easurement of /oating Thic6ness by the Beta Bac6scatter (ethod+

$ This speci®cation is under the *urisdiction of !0T( /ommittee B& on

(etallic and )norganic /oatings and is the direct responsibility of 0ubcommittee

B$ on 'ngineering /oatings

/urrent

edition

approved

(ay

$,

$7

-ublished

=eb

$

5riginally

published as B 734 > 4 .ast previous edition B 734 > 4 "#+ Annual Book of ASTM Standards, ?ol +2

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B 734

deface visible surfaces on the assembled article Ahen neces&sary, the signi®cant surface shall be indicated on the drawing of the article, or by the provision of suitably mar6ed samples

95T' $Ahen

signi®cant

surfaces

are

involved

on

which

the

speci®ed

thic6ness of coating cannot readily be controlled, such as threads, holes,

deep recesses, and bases of angles, it will be necessary to apply thic6er

coatings on the more accessible surfaces, or to use special rac6ing or both

3$+ inspection lot a collection of coated articles that; are

of the same type; have been produced to the same speci®ca&tions; have been coated by a single supplier at one time, or at

approximately the same time, under essentially identical con&

ditions; and are submitted for acceptance or re*ection as a

group3+ De®nitions=or de®nitions of the technical terms used

in this speci®cation see Terminology B 374

4.

Classi®cation4$ The electrodeposited copper is classi®ed according to

thic6ness of the electrodeposit in the following table8

C)ass Mini*+* Thickness, *

"%

"%

"0 "0

1" 1"

% %

- Thickness speci.e'

95T' +=or electroforming applications, that re%uire much thic6er

applications, see uide B 3+

5. Ordering Information

2$ The buyer shall supply to the producer in the purchase

order

or

engineering

drawings;

mar6ed

samples

or

other governing documents the following information8

2$$ Title, !0T( designation number "0peci®cation

B 734#, and date of issue

2$+ /lassi®cation or thic6ness of electrodeposited copper

"see 4$#,

2$3 0igni®cant surfaces if other than de®ned in 3$$,

2$4 0ampling plan "0ection 7#,

2$2 9umber of test specimens for destructive testing

"0ection #, and

2$< Thic6ness, adhesion, solderability, porosity and num&

ber of pores acceptable, or hydrogen embrittlement tests and

methods re%uired "0ection #

2+

Ahere

re%uired,

dimensional

tolerances

allowed

for

the

speci®ed electroplated copper thic6ness shall be speci®ed

23 )n addition to the re%uirements of 2$ and when the parts

to be electroplated are supplied to the electroplater by the

buyer, the buyer shall also supply the following information as

re%uired

23$ )dentity of the base material by alloy identi®cation

such as !0T(, !)0), or 0!' numbers, or e%uivalent compo&

sition information,

23+ 1ardness of the parts, and

233 1eat treatment for stress relief, whether it has been

performed or is re%uired

24 )f re%uired by either party, the manufacturer of the parts

to be electroplated shall provide the electroplating facility withseparate test specimens "see section $#

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.

Coating

Re!uirements

<$ AppearanceThe coating on the signi®cant surfaces of the product shall be smooth and free of visual defects such as blisters, pits, roughness, crac6s, C a6ing, burned deposits, and uncoated areas The boundaries of electroplating that cover only a portion of the surface shall, after ®nishing as indicated in the drawing, be free of beads, nodules, *agged edges and other detrimental irregularities )mperfections and variations in appearance in

the

coating

that

arise

from

surface

conditions

of

the

basis metal "scratches, pores, roll mar6s, inclusions, etc# and

that persist in the ®nish despite the observance of good

metal ®nishing practices shall not be cause for re*ection

95T' 3'lectroplated ®nishes generally perform better when

the substrate over which they are applied is smooth and free of deep

scratches, torn metal, pores, inclusions, and other defects )t is

recommended that the speci®cations covering the un®nished product

provide limits for these defects ! metal ®nisher can often

remove defects through special treatments such as grinding,

polishing, abrasive blasting, and special chemical treatments

1owever, these are not normal treatment steps Ahen they are

desired, they must be agreed upon between the buyer and the

producer

<+

ThicknessThe

thic6ness

of

the

copper

coating

on

the signi®cant surfaces shall conform to the re%uirements of the speci®ed class as de®ned in 0ection 4

95T' 4?ariation in the coating thic6ness from point&to&point on

a coated article is an inherent characteristic of electroplating

processes Therefore, the coating thic6ness will have to exceed the

speci®ed value at some points on the signi®cant surfaces to ensure

that the thic6ness e%uals or exceeds the speci®ed value at all

points !s a result, the average coating thic6ness on an article will usually

be greater than the speci®ed value; how much greater is largely determined

by the shape of the article "see -ractice B 27# and the characteristics of

the electroplating process !dditionally, the average coating thic6ness on

an article will vary from article to article within a production lot

Therefore, if all of the articles in a production lot are to meet the thic6ness

re%uirement, the average coating thic6ness of the production lot as a

whole will be greater than the average necessary to ensure that a single

article meets the re%uirements

95T' 2Ahen electroplating threaded parts such as machine screws,

care is re%uired to avoid too much plate buildup on the crest of the thread

)n

such

applications

a

maximum

plate

thic6ness

allowable

on

the

crests

may re%uire that thic6nesses in other areas be thinner

<3 PorosityAhen speci®ed, the coating shall be suffi&ciently free of pores to pass the porosity test speci®ed in 4<4 SolderabilityAhen speci®ed, the coating shall meet

the re%uirements of Test (ethod B <7<2 Pretreatment of Iron and Steel for Reducing the Risk of

ydrogen !mbrittlement -arts for critical applications that are made of steels with ultimate tensile strengths of $ (-a, hardness of 3$ 1/ or greater, that have been machined, ground, cold formed, or cold straightened subse%uent to heat treatment, shall re%uire stress relief heat treatment when speci®ed by the purchaser, the tensile strength to be supplied

by

the

purchaser

0peci®cation

B

4

may

be

consulted

for

a list of pretreatments that are used widely

<< Post "oating Treatment of Iron and Steel for Reducing the Risk of ydrogen !mbrittlement -arts for critical appli&cations that are made of steels with ultimate tensile strengths of $ (-a, hardness of 3$ 1/ or greater, as well as surface hardened parts, shall re%uire post coating hydrogen embrittle&ment relief ba6ing when speci®ed by the purchaser, the tensile

+

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B 734

strength to be supplied by the purchaser 0peci®cation B 2may be consulted for a list of post treatments that are used

widely

<7

Peening

of

Metal

Parts)f

peening

is

re%uired

before electroplating to induce residual compressive stress to increase

fati%ue strength and resistance to stress corrosion crac6ing of the metal parts, refer to ().&0&$3$<2, ().&&$4$, ().&A&$4, and 0peci®cation B 2$< Supplementary Re#uirements:<$ Packaging )f pac6aging re%uirements are to be met

under this speci®cation, they shall be in accordance with -ractice : 32$, or as speci®ed in the contract or order

95T' <

Caution" 0ome contemporary pac6aging materials may emit

fumes that are deleterious to the surface of the coating

#. Sampling

7$ The sampling plan used for the inspection of a %uantityof

the

coated

articles

shall

be

as

agreed

upon

between

the purchaser and the seller

95T' 7Esually, when a collection of coated articles, the inspection

lot "7+#, is examined for compliance with the re%uirements placed on the

articles, a relatively small number of the articles, the sample, is selected at

random and is inspected The inspection lot then is classi®ed as complying

or not complying with the re%uirements based on the results of the

inspection of the sample The siDe of the sample and the criteria of

compliance are determined by the application of statistics The procedure

is 6nown as sampling inspection Three standards, Test (ethod B <+,

uide B <7, and (ethod B 7<+ contain sampling plans that are designed

for the sampling inspection of coatings Test (ethod B <+ contains four

sampling plans, three for use with tests that are non&destructive and one

when they are destructive The buyer and seller may agree on the plan or

plans

to

be

used

)f

they

do

not,

Test

(ethod

B

<+

identi®es

the

plan

to be used uide B <7 provides a large number of plans and also gives

guidance in the selection of a plan Ahen uide B <7 is speci®ed, the

buyer and seller need to agree on the plan to be used (ethods B 7<+ can

be used only for coating re%uirements that have numerical limit, such as

coating thic6ness The test must yield a numerical value and certain

statistical re%uirements must be met (ethods B 7<+ contains several

plans and also gives instructions for calculating plans to meet special

needs The buyer and the seller may agree on the plan or plans to be used

)f they do not, (ethods B 7<+ identi®es the plan to be used

95T' Ahen both destructive and non&destructive tests exist for the

measurement of a characteristic, the purchaser needs to state which is to

be used so that the proper sampling plan is selected! test may destroy the

coating but in a non&critical area; or, although it may destroy the coating,

a tested part can be reclaimed by stripping and recoating The purchaser

needs to state whether the test is to be considered destructive or

non&destructive

7+ !n inspection lot shall be de®ned as a collection of coated articles that are of the same 6ind, that have been produced to the same speci®cations, that have been coated by a single supplier at one time, or at approximately the same time under essentially identical conditions, and that are submitted for acceptance or re*ection as a group73 )f special test specimens are used to represent the coatedarticles in a test, the number used shall be that re%uired in

$$

$. Test %et&ods

$ The permission or the re%uirement to use special test

specimens, the number to be used, the material from whichthey are to be made, and their shape and siDe shall be stated by the purchaser

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95T' Test specimens often are used to represent the coated

articles in a test if the articles are of a siDe, shape, or material that is

not suitable for the test, or if it is preferred not to submit articles to a

destructive test because, for example, the articles are expensive or

few in number The specimen should duplicate the characteristics of

the article that in C uence the property being tested

$$ 0pecial test specimens used to represent articles inan adhesion, porosity, corrosion resistance, or appearance test shall be made of the same material, in thesame metallurgical condition, and have the same surface

condition

as

the

articles

they

represent,

and

be

placed

inthe production lot of and be processed along with thearticles they represent$+ 0pecial test specimens used to represent articles

in a coating thic6ness test may be made of a material that issuitable for the test method even if the represented articleis not of the same material =or example, a low&carbonsteel specimen may represent a brass article when themagnetic thic6ness test is used "Test (ethod B 4# Thethic6ness specimen need not be carried through thecomplete process with the represented article )f not,introduce it into the process at the point where the coatingis applied and carry it through all steps that have a bearingon the coating thic6ness )n rac6 plating, rac6 thespecimen

in

the

same

way

with

the

same

distance

fromand orientation with the anodes and other items in the process as the article it represents

95T' $Ahen special test specimens are used to represent

coated articles in a thic6ness test, the specimens will not necessarily

have the same thic6ness and thic6ness distribution as the articles

unless the specimens and the articles are of the same general

siDe and shape Therefore, before ®nished articles can be accepted on

the basis of a thic6ness test performed on special test specimens,

the relationship between the thic6ness on the specimen and the thic6ness

on the part needs to be established The criterion of acceptance is that

thic6ness on the specimen that corresponds to the re%uired thic6ness on

the article

+ Thickness(easure the coating thic6ness at locations on the signi®cant surface designated by the purchser, and ma6e the measurement with an accuracy of $ F or better by use of one of the following test methods8 Test (ethods B 47, B 4,

B

24,

B

2<,

and

B

2

95T' $$5ther thic6ness measurement methods may be used where it

can be demonstrated that the uncertainty is less than $ F

3 AdhesionEse one or more of the methods described in

Test (ethods B 27$ as agreed and as speci®ed in the purchase order or other specifying document4 Porosity/onduct the ferroxyl test as described in

!ppendix @$ 5bserve the results after 2 min The part fails if more than the number of pores per unit area speci®ed by the purchaser is found2 Solderability/onduct the test in accordance with Test

(ethod B <7 The coating shall be deemed solderable if the solder coating is adherent, bright, smooth, and uniform over at

least

2

F

of

the

test

surface

95T' $+'lectroplated copper surfaces become more difficult to

solder as they age )t may be necessary to clean the copper surface *ust

prior to the soldering test or soldering operation

< !mbrittlement Relief -arts shall be examined visually for crac6s indicating embrittlement failure, or the effectiveness of the relief treatment shall be determined by a procedure speci®ed by the purchaser

3

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B 734

95T' $3(ethod = 2$ describes hydrogen embrittlement testing that

utiliDes specially machined test specimens

'. Re(ection and Re&earing

$

(aterials

that

fail

to

conform

to

the

re%uirements

of

this

speci®cation shall be re*ected e*ection shall be reported to

the producer or the supplier promptly, and in writing )n case of dissatisfaction with the results of a test, the producer or supplier may ma6e a claim for a rehearing =inishes that show

imperfections during subse%uent manufacturing operations may be re*ected

1). Certi®cation

$$ The purchaser may re%uire in the purchase order or

contract that the producer or supplier give to the purchaser

certi®cation

that

the

®nish

was

produced

and

tested

in

accor&

dance with this speci®cation and found to meet the re%uire&

ments The purchaser may similarly re%uire that a report of the

test results be furnished

*++,-DI

/-onmandatory Information0

1.

%ODII,D

,RRO

T,ST

/*SO

S,,

ID,

6

#50

1.1

eneral

@$$$ This method reveals discontinuities, such as pores, in electroplated copper on iron or steel

95T' @$$This test is slightly corrosive to copper, particularly if the

test period is extended appreciably "3 min or more# beyond the 2&min

period The test is very sensitive to the super®cial presence of iron, that is,

blue spots can occur on an electrodeposited copper surface that has been

in sufficient contact with a piece of iron to leave a trace of the iron on the

copper surface

1.2 %aterials

@$+$

Three

solutions

and

strips

of

Gwet

strengthH

®lter

paper are re%uired@$+$$ Solution A, is prepared by dissolving 2 g of white

gelatine and 2 g of sodium chloride in $ . of warm "42I/#distilled water@$+$+ Solution B, is prepared by dissolving 2 g of

sodium chloride and $ g of a non&ionic wetting agent in $ .of distilled water@$+$3 Solution " , is prepared by dissolving $ g of

potassium ferricyanide in $ . of distilled water

1.3

+rocedure

@$3$ )mmerse ®lter paper strips in 0olution A "which is 6ept sufficiently warm to 6eep the gelatine dissolved#, then remove and allow to dry Just before use, immerse the dry ®lter paper strips in 0olution B *ust long enough to thoroughly wet all of the ®lter paper =irmly press the ®lter paper against the thoroughly cleaned and degreased electroplated copper surface to be tested !llow 2&min contact time for the test period "see 9ote @$$# )f the ®lter paper should become dry during the test, moisten again with 0olution B emove the papers at the end of the contact period and place at once into 0olution "

0harply

de®ned

blue

mar6ings

will

appear

on

the

papers

indicating basis metal corrosion or porosity

1.4 Report

@$4$ The report shall include the following information8 @$4$$ The area of surface tested@$4$+ The total number and diameter of all spots on the

®lter paper oriented to surface area tested@$4$3 The highest number of spots visible within a

s%uare area as de®ned and speci®ed by the purchaser

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This stan'ar' is s+bect to revision at any ti*e by the responsib)e technica) co**ittee an' *+st be reviee' every .ve years an'

i/

not

revise',

either

reapprove'

or

ith'ran( 2o+r

co**ents

are

invite'

either

/or

revision

o/

this

stan'ar'

or

/or

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