ASTM B867-95(2023)
(Specification)Standard Specification for Electrodeposited Coatings of Palladium-Nickel for Engineering Use
Standard Specification for Electrodeposited Coatings of Palladium-Nickel for Engineering Use
ABSTRACT
This specification establishes the requirements for electrodeposited palladium-nickel (Pd-Ni) coatings for engineering applications. Composite coatings consisting of palladium-nickel and a thin gold over-plate for applications involving electrical contacts are also covered. The classification system for the coatings covered here shall be specified by the basis metal, the thickness of the underplating, the composition type and thickness class of the palladium-nickel coating, and the grade of the gold overplating. Coatings should be sampled, tested, and conform to specified requirements as to purity, appearance, thickness, composition, adhesion, ductility, and integrity (including gross defects, mechanical damage, porosity, and microcracks). Alloy composition shall be examined either by wet method, X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Auger or electron probe X-ray microanalysis (EPMA), or wavelength dispersive spectroscopy (WDS). Coating adhesion shall be analyzed either by bend, heat, or cutting test.
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).2
Note 1: Electroplated deposits generally have a lower density than their wrought metal counterparts.
Approximate Hardness (HK25)
Gold
50–250
Palladium
75–600
Platinum
150–550
Palladium-Nickel
300–650
Rhodium
750–1100
Ruthenium
600–1300
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
General Information
Relations
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: B867 − 95 (Reapproved 2023)
Standard Specification for
Electrodeposited Coatings of Palladium-Nickel for
Engineering Use
This standard is issued under the fixed designation B867; 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 1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 Composition—This specification covers requirements
ization established in the Decision on Principles for the
for electrodeposited palladium-nickel coatings containing be-
Development of International Standards, Guides and Recom-
tween 70 mass % and 95 mass % of palladium metal. Com-
mendations issued by the World Trade Organization Technical
posite coatings consisting of palladium-nickel and a thin gold
Barriers to Trade (TBT) Committee.
overplate for applications involving electrical contacts are also
covered.
2. Referenced Documents
1.2 Properties—Palladium is the lightest and least noble of
2.1 ASTM Standards:
the platinum group metals. Palladium-nickel is a solid solution
B183 Practice for Preparation of Low-Carbon Steel for
alloy of palladium and nickel. Electroplated palladium-nickel
Electroplating
alloys have a density between 10 and 11.5, which is substan-
B242 Guide for Preparation of High-Carbon Steel for Elec-
tially less than electroplated gold (17.0 to 19.3) and compa-
troplating
rable to electroplated pure palladium (10.5 to 11.8). This yields
B254 Practice for Preparation of and Electroplating on
a greater volume or thickness of coating per unit mass and,
Stainless Steel
consequently, some saving of metal weight. The hardness
B281 Practice for Preparation of Copper and Copper-Base
range of electrodeposited palladium-nickel compares favorably
Alloys for Electroplating and Conversion Coatings
with electroplated noble metals and their alloys (1, 2).
B322 Guide for Cleaning Metals Prior to Electroplating
NOTE 1—Electroplated deposits generally have a lower density than
B343 Practice for Preparation of Nickel for Electroplating
their wrought metal counterparts.
with Nickel
Approximate Hardness (HK )
B374 Terminology Relating to Electroplating
Gold 50–250
B481 Practice for Preparation of Titanium and Titanium
Palladium 75–600
Platinum 150–550 Alloys for Electroplating
Palladium-Nickel 300–650
B482 Practice for Preparation of Tungsten and Tungsten
Rhodium 750–1100
Alloys for Electroplating
Ruthenium 600–1300
B487 Test Method for Measurement of Metal and Oxide
1.3 The values stated in SI units are to be regarded as the
Coating Thickness by Microscopical Examination of
standard. The values given in parentheses are for information
Cross Section
only.
B488 Specification for Electrodeposited Coatings of Gold
1.4 This standard does not purport to address all of the
for Engineering Uses
safety concerns, if any, associated with its use. It is the
B489 Practice for Bend Test for Ductility of Electrodepos-
responsibility of the user of this standard to establish appro-
ited and Autocatalytically Deposited Metal Coatings on
priate safety, health, and environmental practices and deter-
Metals
mine the applicability of regulatory limitations prior to use.
B507 Practice for Design of Articles to Be Electroplated on
Racks
B542 Terminology Relating to Electrical Contacts and Their
Use
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and is under the direct responsibility of Subcom-
mittee B08.03 on Engineering Coatings.
Current edition approved Nov. 1, 2023. Published November 2023. Originally
approved in 1995. Last previous edition approved in 2018 as B867 – 95 (2018). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/B0867-95R23. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this specification. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B867 − 95 (2023)
B558 Practice for Preparation of Nickel Alloys for Electro- 4. Classification
plating
4.1 Orders for articles to be plated in accordance with this
B568 Test Method for Measurement of Coating Thickness
specification shall specify the coating system, indicating the
by X-Ray Spectrometry
basis metal, the thicknesses of the underplatings, the type and
B571 Practice for Qualitative Adhesion Testing of Metallic
thickness class of the palladium-nickel coating, and the grade
Coatings
of the gold overplating according to Table 1, Table 2, and Table
B602 Guide for Attribute Sampling of Metallic and Inor-
3. See Section 7.
ganic Coatings
B697 Guide for Selection of Sampling Plans for Inspection
5. Ordering Information
of Electrodeposited Metallic and Inorganic Coatings
5.1 In order to make the application of this specification
B741 Test Method for Porosity In Gold Coatings On Metal
complete, the purchaser shall supply the following information
Substrates By Paper Electrography (Withdrawn 2005)
to the seller in the purchase order or other governing document:
B748 Test Method for Measurement of Thickness of Metal-
5.1.1 The name, designation, and date of issue of this
lic Coatings by Measurement of Cross Section with a
specification;
Scanning Electron Microscope
5.1.2 The coating system including basis metal, composi-
B762 Guide of Variables Sampling of Metallic and Inorganic
tion type, thickness class and gold overplate grade (see 4.1 and
Coatings
Table 1, Table 2, and Table 3);
B765 Guide for Selection of Porosity and Gross Defect Tests
5.1.3 Presence, composition, and thickness of underplating
for Electrodeposits and Related Metallic Coatings
(see 3.2.1). For nickel underplating see 6.5.1;
B798 Test Method for Porosity in Gold or Palladium Coat-
5.1.4 Significant surfaces shall be defined (see 3.2.3);
ings on Metal Substrates by Gel-Bulk Electrography
5.1.5 Requirements, if any, for porosity testing (see 9.6);
B799 Test Method for Porosity in Gold and Palladium
5.1.6 (Steel parts only) Stress relief if required (see Speci-
Coatings by Sulfurous Acid/Sulfur-Dioxide Vapor
fication B849);
B809 Test Method for Porosity in Metallic Coatings by
5.1.7 (Steel parts only) Hydrogen embrittlement relief (see
Humid Sulfur Vapor (“Flowers-of-Sulfur”)
B850 );
B827 Practice for Conducting Mixed Flowing Gas (MFG)
5.1.8 Sampling plan employed (see Section 8); and,
Environmental Tests
5.1.9 Requirement, if any, for surface coating cleanliness
B845 Guide for Mixed Flowing Gas (MFG) Tests for Elec-
(absence of residual salts). See Appendix X6.
trical Contacts
B849 Specification for Pre-Treatments of Iron or Steel for
6. Manufacture
Reducing Risk of Hydrogen Embrittlement
6.1 Any process that provides an electrodeposit capable of
B850 Guide for Post-Coating Treatments of Steel for Reduc-
meeting the specified requirements will be acceptable.
ing the Risk of Hydrogen Embrittlement
D1125 Test Methods for Electrical Conductivity and Resis- 6.2 Substrate:
tivity of Water
6.2.1 The surface condition of the basis metal should be
D3951 Practice for Commercial Packaging specified and should meet this specification prior to the plating
of the parts.
3. Terminology
6.2.2 Defects in the surface of the basis metal, such as
3.1 Definitions: Many terms used in this specification are scratches, porosity, pits, inclusions, roll and die marks, laps,
defined in Terminology B374 or B542. cracks, burrs, cold shuts, and roughness may adversely affect
the appearance and performance of the deposit, despite the
3.2 Definitions of Terms Specific to This Standard:
observance of the best plating practice. Any such defects on
3.2.1 overplating, n—a coating applied onto the topmost
significant surfaces should be brought to the attention of the
palladium-nickel coating. The thickness of an overplating or
supplier and the purchaser.
“flash” is usually less than 0.25 μm.
6.2.3 Clean the basis metal as necessary to ensure a satis-
3.2.2 significant surfaces, n—those surfaces normally vis-
factory surface for subsequent electroplating in accordance
ible (directly or by reflection) or which are essential to the
with Practices B183, B242, B254, B281, B322, B343, B481,
serviceability or function of the article; or which can be the
B482, and B558.
source of corrosion products or tarnish films that interfere with
6.2.4 Proper preparatory procedures and thorough cleaning
the function or desirable appearance of the article. The signifi-
of the basis metal are essential for satisfactory adhesion and
cant surfaces shall be indicated on the drawings of the parts, or
performance of these coatings. The surface must be chemically
by the provision of suitably marked samples.
3.2.3 underplating, n—a metallic coating layer or layers
TABLE 1 Composition Type
between the basis metal or substrate and the palladium-nickel
coating. The thickness of an underplating is usually greater Type Nominal Composition (Mass %) Range (Mass% Pd)
than 1 μm, in contrast to a strike which is thinner. I 75 % Pd/25 % Ni 70–80 % Pd
II 80 % Pd/20 % Ni 75–85 % Pd
III 85 % Pd/15 % Ni 80–90 % Pd
The last approved version of this historical standard is referenced on IV 90 % Pd/10 % Ni 85–95 % Pd
www.astm.org.
B867 − 95 (2023)
A
TABLE 2 Thickness Class
6.5.3 Plating—Good practice calls for the work to be
Thickness Class Minimum Thickness of Pd-Ni (μm)
electrically connected when entering the palladium-nickel
0.4 0.4
solution.
0.5 0.5
0.7 0.7
NOTE 5—Some palladium-nickel electroplating solutions attack copper.
1.0 1.0
This can result in codeposition of copper impurity. The situation is further
1.3 1.3
aggravated when low current densities are utilized. Copper can be
1.5 1.5 2
removed from solutions by low current density electrolysis (0.1 mA ⁄cm
2.0 2.0
to 0.3 mA ⁄cm ).
2.5 2.5
3.0 3.0
6.5.4 Gold Overplating—Apply a thin gold overplating after
A
See Appendix X3 on Electrical Contact Performance Versus Thickness Class.
the palladium-nickel in any application in which palladium-
nickel plated electrical connectors are mated together in a
contact pair. This process is necessary to preserve the perfor-
A
TABLE 3 Gold Overplate
mance of the contact surface. See Appendix X1 for other
MIL-G- Thickness
Grade Type Hardness (Code)
reasons for using a gold overplate.
45204 Range
0 No Overplate . . .
NOTE 6—When using Type 1 gold, the thickness of the gold overplate
1 1 (99.9 % Au min) III 90 HK max (A) 0.05–0.12 μm
shall not exceed 0.12 μm (5 μin.) due to increased risk of degrading
2 2 (99.7 % Au min) I 130–200 HK (C) 0.05–0.25 μm
durability and increasing the coefficient of friction.
A
See Specification B488 and Appendix X1 and Appendix X2.
6.5.5 Residual Salts—For rack and barrel plating
applications, residual plating salts can be removed from the
articles by a clean, hot (50 °C to 100 °C) water rinse. A
minimum rinse time of 2.5 min (racks) or 5 min (barrel) is
clean and continuously conductive, that is, without inclusions
suggested. Best practice calls for a minimum of three dragout
or other contaminants. The coatings must be smooth and as free
rinses and one running rinse with dwell times of 40 s in each
of scratches, gouges, nicks, and similar imperfections as
station when rack plating and 80 s when barrel plating. Modern
possible.
high-velocity impingement type rinses can reduce this time to
a few seconds. This is particularly useful in automatic reel-to-
NOTE 2—A metal finisher can often remove defects through special
treatments such as grinding, polishing, abrasive blasting, chemical reel applications where dwell times are significantly reduced.
treatments, and electropolishing. However, these may not be normal in the
See Appendix X6.
treatment steps preceding the plating, and a special agreement is indicated.
6.3 If required (see 5.1.6), steel parts with a hardness greater
7. Coating Requirements
than 1000 MPa (31 HRC) shall be given a suitable stress relief
7.1 Nature of Coating—The palladium-nickel deposit shall
heat treatment prior to plating in accordance with Specification
have a minimum purity of 70 mass % palladium.
B849. Such stress relief shall not reduce the hardness to a value
7.2 Composition—The composition of the palladium-nickel
below the specified minimum. Avoid acid pickling of high
electrodeposit shall be within 65 mass % of the specified type.
strength steels.
6.3.1 Apply the coating after all basis metal preparatory heat
7.3 Appearance—Palladium-nickel coatings shall be
treatments and mechanical operations on significant surfaces
coherent, continuous, and have a uniform appearance to the
have been completed.
extent that the nature of the basis metal and good commercial
practices permit.
6.4 Racking:
6.4.1 Position parts to allow free circulation of solution over
7.4 Thickness—Everywhere on the significant surface (see
all surfaces. The location of rack or wire marks in the coating
5.1), the thickness of the palladium-nickel coating shall be
should be agreed upon between the producer and supplier.
equal to or exceed the specified thickness. The maximum
thickness, however, shall not exceed the drawing tolerance.
6.5 Plating Process:
6.5.1 Nickel Underplating—Apply a nickel underplating
NOTE 7—The coating thickness requirement of this specification is a
before the palladium-nickel when the product is made from
minimum requirement, that is, the coating thickness is required to equal or
copper or copper alloy. Nickel underplatings are also applied
exceed the specified thickness everywhere on the significant surfaces
while conforming to all maximum thickness tolerances given in the
for other reasons. See Appendix X5.
engineering drawing. Variation in the coating thickness from point to point
NOTE 3—In certain instances where high frequency analog signals are
on a coated article is an inherent characteristic of electroplating processes.
employed, such as wave guides, the magnetic properties of nickel may
The coating thickness at any single point on the significant surface,
attenuate the signal. Palladium-nickel itself is non-ferromagnetic when the
therefore, will sometimes have to exceed the specified value in order to
nickel content is less than 14 mass %.
ensure tha
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