ASTM B867-95(2003)
(Specification)Standard Specification for Electrodeposited Coatings of Palladium-Nickel for Engineering Use
Standard Specification for Electrodeposited Coatings of Palladium-Nickel for Engineering Use
SCOPE
1.1 Composition—This specification covers requirements for electrodeposited palladium-nickel coatings containing between 70 and 95 mass % of palladium metal. Composite coatings consisting of palladium-nickel and a thin gold overplate for applications involving electrical contacts are also covered.
1.2 Properties—Palladium is the lightest and least noble of the platinum group metals. Palladium-nickel is a solid solution alloy of palladium and nickel. Electroplated palladium-nickel alloys have a density between 10 and 11.5, which is substantially less than electroplated gold (17.0 to 19.3) and comparable to electroplated pure palladium (10.5 to 11.8). This yields a greater volume or thickness of coating per unit mass and, consequently, some saving of metal weight. The hardness range of electrodeposited palladium-nickel compares favorably with electroplated noble metals and their alloys (1,2).
Note 1—Electroplated deposits generally have a lower density than their wrought metal counterparts.Approximate Hardness (HK25)Gold 50-250Palladium75-600Platinum150-550Palladium-Nickel300-650Rhodium 750-1100Ruthenium600-1300
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
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Designation: B 867 – 95 (Reapproved 2003)
Standard Specification for
Electrodeposited Coatings of Palladium-Nickel for
Engineering Use
This standard is issued under the fixed designation B 867; 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 183 Practice for Preparation of Low-Carbon Steel for
Electroplating
1.1 Composition—This specification covers requirements
B 242 Practice for Preparation of High-Carbon Steel for
for electrodeposited palladium-nickel coatings containing be-
Electroplating
tween 70 and 95 mass % of palladium metal. Composite
B 254 Practice for Preparation of and Electroplating on
coatings consisting of palladium-nickel and a thin gold over-
Stainless Steel
plate for applications involving electrical contacts are also
B 281 Practice for Preparation of Copper and Copper-Base
covered.
Alloys for Electroplating and Conversion Coatings
1.2 Properties—Palladium is the lightest and least noble of
B 322 Practice for Cleaning Metals Prior to Electroplating
the platinum group metals. Palladium-nickel is a solid solution
B 343 Practice for Preparation of Nickel for Electroplating
alloy of palladium and nickel. Electroplated palladium-nickel
with Nickel
alloys have a density between 10 and 11.5, which is substan-
B 374 Terminology Relating to Electroplating
tially less than electroplated gold (17.0 to 19.3) and compa-
B 481 Practice for Preparation of Titanium and Titanium
rable to electroplated pure palladium (10.5 to 11.8).This yields
Alloys for Electroplating
a greater volume or thickness of coating per unit mass and,
B 482 Practice for Preparation of Tungsten and Tungsten
consequently, some saving of metal weight. The hardness
Alloys for Electroplating
rangeofelectrodepositedpalladium-nickelcomparesfavorably
B 487 Test Method for Measurement of Metal and Oxide
with electroplated noble metals and their alloys (1, 2).
Coating Thickness by Microscopical Examination of a
NOTE 1—Electroplated deposits generally have a lower density than 3
Cross Section
their wrought metal counterparts.
B 488 Standard Specification for Electrodeposited Coatings
Approximate Hardness (HK )
of Gold for Engineering Uses
Gold 50–250
B 489 Practice for Bend Test for Ductility of Electrodepos-
Palladium 75–600
Platinum 150–550
ited and Autocatalytically Deposited Metal Coatings on
Palladium-Nickel 300–650
Metals
Rhodium 750–1100
B 507 Practice for Design ofArticles to Be Electroplated on
Ruthenium 600–1300
Racks
1.3 The values stated in SI units are to be regarded as the
B 542 Terminology Relating to Electrical Contacts and
standard. The values given in parentheses are for information
Their Use
only.
B 558 Practice for Preparation of NickelAlloys for Electro-
1.4 This standard does not purport to address all of the
plating
safety concerns, if any, associated with its use. It is the
B 568 Test Method for Measurement of Coating Thickness
responsibility of the user of this standard to establish appro-
by X-Ray Spectrometry
priate safety and health practices and determine the applica-
B 571 Practice for QualitativeAdhesion Testing of Metallic
bility of regulatory limitations prior to use.
Coatings
2. Referenced Documents B 578 Test Method for Microhardness of Electroplated
Coatings
2.1 ASTM Standards:
B 602 Test Method for Attribute Sampling of Metallic and
Inorganic Coatings
This specification is under the jurisdiction of ASTM Committee B08 on B 689 Specification for Electroplated Engineering Nickel
Metallic and Inorganic Coatings and is under the direct responsibility of Subcom-
Coatings
mittee B08.08.01 on Engineering Coatings.
Current edition approved Feb. 10, 2003. Published May 2003. Originally
approved in 1995. Last previous edition approved in 1995 as B 867 – 95.
The boldface numbers in parentheses refer to the list of references at the end of 3
Annual Book of ASTM Standards, Vol 02.05.
this specification. 4
Annual Book of ASTM Standards, Vol 02.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B 867 – 95 (2003)
TABLE 1 Composition Type
B 697 Guide for Selection of Sampling Plans for Inspection
of Electrodeposited Metallic and Inorganic Coatings Type Nominal Composition (Mass %) Range (Mass% Pd)
B 741 Test Methods for Porosity in Gold Coatings on Metal
I 75 % Pd/25 % Ni 70–80 % Pd
II 80 % Pd/20 % Ni 75–85 % Pd
Substrates by Paper Electrography
III 85 % Pd/15 % Ni 80–90 % Pd
B 748 Test Method for Measurement of Thickness of Me-
IV 90 % Pd/10 % Ni 85–95 % Pd
tallic Coatings by Measurement of a Cross Section with a
Scanning Electron Microscope
A
B 762 Method of Variables Sampling of Metallic and Inor-
TABLE 2 Thickness Class
ganic Coatings
Thickness Class Minimum Thickness of Pd-Ni (µm)
B 765 Guide for Selection of Porosity Tests for Electrode-
0.4 0.4
posits and Related Metallic Coatings
0.5 0.5
0.7 0.7
B 798 Test Method for Porosity in Gold or Palladium
4 1.0 1.0
Coatings on Metal Substrates by Gel-Bulk Electrography
1.3 1.3
B 799 Test Method for Porosity in Gold and Palladium
1.5 1.5
2.0 2.0
Coatings by Sulfurous Acid/Sulfur-Dioxide Vapor
2.5 2.5
B 809 Test Method for Porosity in Metallic Coatings by
3.0 3.0
Humid Sulfur Vapor (“Flowers-of-Sulfur”)
A
See Appendix X3 on Electrical Contact Performance Versus Thickness Class.
B 827 Practice for Conducting Mixed Flowing Gas (MFG)
Environmental Tests
A
TABLE 3 Gold Overplate
B 845 Guide to Mixed Flowing Gas (MFG) Tests for
4 MIL-G- Thickness
Electrical Contacts Grade Type Hardness (Code)
45204 Range
B 849 Specification for Pre-Treatments of Iron or Steel for
0 No Overplate . . .
Reducing Risk of Hydrogen Embrittlement
1 1 (99.9 % Au min) III 90 HK max (A) 0.05–0.12 µm
B 850 Specification for Post-Coating Treatments Steel for
2 2 (99.7 % Au min) I 130–200 HK (C) 0.05–0.25 µm
A
Reducing Risk of Hydrogen Embrittlement
See Specification B 488 and Appendix X1 and Appendix X2.
D 1125 Test Methods for Electrical Conductivity and Re-
sistivity of Water
5. Ordering Information
D 3951 Practice for Commercial Packaging
5.1 In order to make the application of this specification
3. Terminology complete, the purchaser shall supply the following information
tothesellerinthepurchaseorderorothergoverningdocument:
3.1 Definitions: Many terms used in this specification are
5.1.1 The name, designation, and date of issue of this
defined in Terminology B 374 or B 542.
specification;
3.2 Definitions of Terms Specific to This Standard:
5.1.2 The coating system including basis metal, composi-
3.2.1 overplating, n—a coating applied onto the topmost
tion type, thickness class and gold overplate grade (see 4.1 and
palladium-nickel coating. The thickness of an overplating or
Table 1, Table 2, and Table 3);
“flash” is usually less than 0.25 µm.
5.1.3 Presence, composition, and thickness of underplating
3.2.2 significant surfaces, n—those surfaces normally vis-
(see 3.2.1). For nickel underplating see 6.5.1;
ible (directly or by reflection) or which are essential to the
5.1.4 Significant surfaces shall be defined (see 3.2.3);
serviceability or function of the article; or which can be the
5.1.5 Requirements, if any, for porosity testing (see 9.6);
source of corrosion products or tarnish films that interfere with
5.1.6 (Steel parts only) Stress relief if required (see Speci-
the function or desirable appearance of the article. The signifi-
fication B 849);
cant surfaces shall be indicated on the drawings of the parts, or
5.1.7 (Steel parts only) Hydrogen embrittlement relief (see
by the provision of suitably marked samples.
B 850 );
3.2.3 underplating, n—a metallic coating layer or layers
5.1.8 Sampling plan employed (see Section 8); and,
between the basis metal or substrate and the palladium-nickel
5.1.9 Requirement, if any, for surface coating cleanliness
coating. The thickness of an underplating is usually greater
(absence of residual salts). See Appendix X6.
than 1 µm, in contrast to a strike which is thinner.
6. Manufacture
4. Classification
6.1 Any process that provides an electrodeposit capable of
4.1 Orders for articles to be plated in accordance with this
meeting the specified requirements will be acceptable.
specification shall specify the coating system, indicating the
6.2 Substrate:
basis metal, the thicknesses of the underplatings, the type and
6.2.1 The surface condition of the basis metal should be
thickness class of the palladium-nickel coating, and the grade
specified and should meet this specification prior to the plating
ofthegoldoverplatingaccordingtoTable1,Table2,andTable
of the parts.
3. See Section 7.
6.2.2 Defects in the surface of the basis metal, such as
scratches, porosity, pits, inclusions, roll and die marks, laps,
cracks, burrs, cold shuts, and roughness may adversely affect
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 15.09. the appearance and performance of the deposit, despite the
B 867 – 95 (2003)
observance of the best plating practice. Any such defects on gether in a contact pair. This process is necessary to preserve
significant surfaces should be brought to the attention of the the performance of the contact surface. See Appendix X1 for
supplier and the purchaser. other reasons for using a gold overplate.
6.2.3 Clean the basis metal as necessary to ensure a satis-
NOTE 6—When using Type 1 gold, the thickness of the gold overplate
factory surface for subsequent electroplating in accordance
shall not exceed 0.12 µm (5 µin.) due to increased risk of degrading
with Practices B 183, B 242, B 254, B 281, B 322, B 343,
durability and increasing the coefficient of friction.
B 481, B 482 and B 558.
6.5.5 Residual Salts—For rack and barrel plating applica-
6.2.4 Proper preparatory procedures and thorough cleaning
tions, residual plating salts can be removed from the articles by
of the basis metal are essential for satisfactory adhesion and
a clean, hot (50 to 100°C) water rinse. A minimum rinse time
performance of these coatings.The surface must be chemically
of 2.5 min (racks) or 5 min (barrel) is suggested. Best practice
clean and continuously conductive, that is, without inclusions
calls for a minimum of three dragout rinses and one running
orothercontaminants.Thecoatingsmustbesmoothandasfree
rinse with dwell times of 40 s in each station when rack plating
of scratches, gouges, nicks, and similar imperfections as
and 80 s when barrel plating. Modern high-velocity impinge-
possible.
ment type rinses can reduce this time to a few seconds. This is
NOTE 2—A metal finisher can often remove defects through special particularly useful in automatic reel-to-reel applications where
treatments such as grinding, polishing, abrasive blasting, chemical treat-
dwell times are significantly reduced. See Appendix X6.
ments, and electropolishing. However, these may not be normal in the
7. Coating Requirements
treatmentstepsprecedingtheplating,andaspecialagreementisindicated.
7.1 Nature of Coating—The palladium-nickel deposit shall
6.3 Ifrequired(see5.1.6),steelpartswithahardnessgreater
have a minimum purity of 70 mass % palladium.
than 1000 MPa (31 HRC) shall be given a suitable stress relief
7.2 Composition—The composition of the palladium-nickel
heat treatment prior to plating in accordance with Specification
electrodeposit shall be within 65 mass % of the specified type.
B 849. Such stress relief shall not reduce the hardness to a
7.3 Appearance—Palladium-nickel coatings shall be coher-
value below the specified minimum. Avoid acid pickling of
ent, continuous, and have a uniform appearance to the extent
high strength steels.
that the nature of the basis metal and good commercial
6.3.1 Applythecoatingafterallbasismetalpreparatoryheat
practices permit.
treatments and mechanical operations on significant surfaces
7.4 Thickness—Everywhere on the significant surface (see
have been completed.
5.1), the thickness of the palladium-nickel coating shall be
6.4 Racking:
equal to or exceed the specified thickness. The maximum
6.4.1 Positionpartstoallowfreecirculationofsolutionover
thickness, however, shall not exceed the drawing tolerance.
all surfaces. The location of rack or wire marks in the coating
should be agreed upon between the producer and supplier.
NOTE 7—The coating thickness requirement of this specification is a
6.5 Plating Process:
minimumrequirement,thatis,thecoatingthicknessisrequiredtoequalor
6.5.1 Nickel Underplating—Apply a nickel underplating exceed the specified thickness everywhere on the significant surfaces
while conforming to all maximum thickness tolerances given in the
before the palladium-nickel when the product is made from
engineeringdrawing.Variationinthecoatingthicknessfrompointtopoint
copper or copper alloy. Nickel underplatings are also applied
on a coated article is an inherent characteristic of electroplating processes.
for other reasons. See Appendix X5.
The coating thickness at any single point on the significant surface,
therefore, will sometimes have to exceed the specified value in order to
NOTE 3—In certain instances where high frequency analog signals are
ensurethatthethicknessequalsorexceedsthespecifiedvalueatallpoints.
employed, such as wave guides, the magnetic properties of nickel may
Hence, most average coating thicknesses will be greater than the specified
attenuatethesignal.Palladium-nickelitselfisnon-ferromagneticwhenthe
value. How much greater is largely determined by the shape of the article
nickel content is less than 14 mass %.
(see Practice B 507) and the characteristics of the plating process. In
NOTE 4—In applications where forming or flaring operations are to be
addition, the average coating thickness on products will vary from article
applied to the plated component, a ductile nickel electrodeposit should be
to article within a production lot. If all of the articles in a production lot
specified.
are to meet the thickness requirement, the average coating thickness for
6.5.2 Strikes—Good practice suggests the use of a palla-
the production lot as a whole will be greater than the average necessary to
dium strike to follow any underplate or substrate (other than
assure that a single article meets the requirement. See 8.1.
silver or platinum) immediately prior to applying the
7.5 Adhesion—The palladium-nickel coatings shall be ad-
palladium-nickel.
herent to the substrate or underplate when tested by one of the
6.5.3 Plating—Good practice calls for the work to be
procedures
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