ASTM B607-91(2003)

Standard Specification for Autocatalytic Nickel Boron Coatings for Engineering Use

ABSTRACT
This standard contains the requirements for autocatalytic nickel boron alloy coatings deposited from aqueous solutions without the use of external electric sources. The specification classifies the hard, uniform, microporous, and limited corrosion protection coatings as either Type 1 or Type 2 depending on the boron content. Both the physical and mechanical properties of the coatings such as density, hardness, stress, and melting point also vary with the boron content. In general, these coatings are not heat treated to maintain solderability.
SCOPE
1.1 Nickel boron coatings are produced by autocatalytic (electroless) deposition from aqueous solutions. These solutions contain either an alkylamineborane or sodium borohydride as a reducing agent, a source of nickel ions, a buffer, complexant, and control chemicals.
1.2 This standard describes the requirements for coatings of autocatalytic nickel boron deposited from aqueous solutions onto substrates for engineering use. The specification classifies these coatings into two types:
1.2.1 Type 1 coatings have a boron content of 0.1 to less than 3.5 mass percent with the balance nickel.
1.2.2 Type 2 coatings have a boron content of 3.5 to 6 mass percent and a minimum of 90 mass percent nickel.
1.3 The coatings are hard and uniform in thickness, even on irregular shaped parts, and used in a wide range of applications.
1.4 Process solutions formulated with an alkylamineborane usually produce coatings that contain 0.1 to 3.5 % boron. Thin coatings of this type provide bondability and solderability on electronic components such as lead frames, electrical contacts, and headers. To maintain solderability, these coatings are generally not heat treated.
1.5 Process solutions formulated with sodium borohydride are strongly alkaline and are frequently used to plate steel and titanium parts to impart surface hardness and wear resistance properties. Deposits produced from these processes can contain 3 to 5 % boron and thallium or other metals which are used to stabilize the plating solution and modify the coating properties.
1.6 The physical and mechanical properties of these deposits such as density, hardness, stress, and melting point will vary with the boron content. The variation of boron content also affects the quantity and structure of nickel boride precipitated during heat treatment. In the as-plated condition the deposit consists of a predominantly amorphous mixture of nickel and boron with a hardness of about 700 HKN. When the deposit is heated above 300°C the nickel crystallizes, forming nickel clusters of Ni (111) and boron precipitates as nickel boride, Ni3B (211) and (311), increasing the hardness to greater than 1000 HK100 for Type 2 coatings.
1.7 The nickel boron coatings are microporous and offer limited corrosion protection. Their columnar structure, however, is beneficial in reducing wear because it provides a means of trapping lubricants within the surface of the coated part.
1.8 This document describes only autocatalytic nickel boron coatings that have been produced without use of external electric sources.
1.9 The following hazards caveat pertains only to the Test Methods section of this specification:  This standard does not purport to address the safety problems 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.
Note 1—The following AMS standards are not requirements. They are referenced for information only: AMS 2399 and AMS 2433.

General Information

• Status: Historical
• Publication Date: 09-Sep-2003
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.03 - Engineering Coatings

Relations

• Replaces: ASTM B607-91(1998) - Standard Specification for Autocatalytic Nickel Boron Coatings for Engineering Use
• Effective Date: 10-Sep-2003
• Replaced By: ASTM B607-91(2008) - Standard Specification for Autocatalytic Nickel Boron Coatings for Engineering Use
• Effective Date: 01-Aug-2008
• Referred By: ASTM G195-22 - Standard Guide for Conducting Wear Tests Using a Rotary Platform Abraser
• Effective Date: 10-Sep-2003
• Referred By: ASTM B851-04(2020) - Standard Specification for Automated Controlled Shot Peening of Metallic Articles Prior to Nickel, Autocatalytic Nickel, or Chromium Plating, or as Final Finish
• Effective Date: 10-Sep-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: B 607 – 91 (Reapproved 2003)
Standard Specification for
Autocatalytic Nickel Boron Coatings for Engineering Use
This standard is issued under the fixed designation B 607; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope Ni B (211) and (311), increasing the hardness to greater than
1000 HK for Type 2 coatings.
1.1 Nickel boron coatings are produced by autocatalytic 100
1.7 The nickel boron coatings are microporous and offer
(electroless) deposition from aqueous solutions. These solu-
limited corrosion protection. Their columnar structure, how-
tions contain either an alkylamineborane or sodium borohy-
ever,isbeneficialinreducingwearbecauseitprovidesameans
dride as a reducing agent, a source of nickel ions, a buffer,
of trapping lubricants within the surface of the coated part.
complexant, and control chemicals.
1.8 Thisdocumentdescribesonlyautocatalyticnickelboron
1.2 This standard describes the requirements for coatings of
coatings that have been produced without use of external
autocatalytic nickel boron deposited from aqueous solutions
electric sources.
onto substrates for engineering use.The specification classifies
1.9 The following hazards caveat pertains only to the Test
these coatings into two types:
Methods section of this specification: This standard does not
1.2.1 Type 1 coatings have a boron content of 0.1 to less
purport to address the safety problems associated with its use.
than 3.5 mass percent with the balance nickel.
It is the responsibility of the user of this standard to establish
1.2.2 Type 2 coatings haveaboroncontentof3.5to6mass
appropriate safety and health practices and determine the
percent and a minimum of 90 mass percent nickel.
applicability of regulatory limitations prior to use.
1.3 The coatings are hard and uniform in thickness, even on
irregularshapedparts,andusedinawiderangeofapplications.
NOTE 1—The followingAMS standards are not requirements. They are
1.4 Process solutions formulated with an alkylamineborane
referenced for information only: AMS 2399 and AMS 2433.
usually produce coatings that contain 0.1 to 3.5 % boron. Thin
2. Referenced Documents
coatings of this type provide bondability and solderability on
2.1 ASTM Standards:
electronic components such as lead frames, electrical contacts,
and headers. To maintain solderability, these coatings are B 374 Terminology Relating to Electroplating
B 487 Test Method for Measurement of Metal and Oxide
generally not heat treated.
1.5 Process solutions formulated with sodium borohydride Coating Thickness by Microscopical Examination of a
Cross Section
are strongly alkaline and are frequently used to plate steel and
titanium parts to impart surface hardness and wear resistance B 567 Test Method for Measurement of Coating Thickness
by Beta Backscatter Method
properties.Depositsproducedfromtheseprocessescancontain
3 to 5 % boron and thallium or other metals which are used to B 568 Test Method for Measurement of Coating Thickness
by X-Ray Spectrometry
stabilizetheplatingsolutionandmodifythecoatingproperties.
1.6 The physical and mechanical properties of these depos- B 571 Practice for QualitativeAdhesion Testing of Metallic
Coatings
itssuchasdensity,hardness,stress,andmeltingpointwillvary
with the boron content. The variation of boron content also B 578 Test Method for Microhardness of Electroplated
affects the quantity and structure of nickel boride precipitated Coatings
B 602 Test Method for Attribute Sampling of Metallic and
during heat treatment. In the as-plated condition the deposit
consists of a predominantly amorphous mixture of nickel and Inorganic Coatings
B 656 Guide for Autocatalytic (Electroless) Nickel-
boron with a hardness of about 700 HKN. When the deposit is
heated above 300°C the nickel crystallizes, forming nickel Phosphorus Deposition on Metals for Engineering Use
B 667 Practice for Construction and Use of a Probe for
clusters of Ni (111) and boron precipitates as nickel boride,
Measuring Electrical Contact Resistance
B 678 Test Method for Solderability of Metallic-Coated
1 Products
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
B08.08.01 on Engineering Coatings.
Current edition approved Sept. 10, 2003. Published Sept. 2003. Originally
Annual Book of ASTM Standards, Vol 02.05.
approved in 1991. Last previous edition approved in 1998 as B 607 – 91 (1998).
Annual Book of ASTM Standards, Vol 03.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B 607 – 91 (2003)
B 697 Guide for Selection of Sampling Plans for Inspection 4.2.1 Class1—Partsaresuppliedasplatedwithnopostheat
of Electrodeposited Metallic and Inorganic Coatings treatment.
B 762 Test Method of Variables Sampling of Metallic and 4.2.2 Class2—Partsareheattreatedafterplatingtoincrease
Inorganic Coatings hardness. The coating is heat treated at 365 to 385°C for 90
D 2670 Test Method for Measuring Wear Properties of min (see 7.2.4).
Fluid Lubricants (Falex Pin and Vee Block Method) 4.2.3 Class 3—Parts are heat treated after plating at 180 to
D 2714 Test Method for Calibration and Operation of the 200°C for 2 to 23 h to improve coating adhesion on steel and
Falex Block-on-Ring Friction and Wear Testing Machine for hydrogen embrittlement relief of steels (see 7.2.4).
E 39 Test Methods for Chemical Analysis of Nickel 4.2.4 Class 4—Parts are heat treated after plating at 120 to
F 519 Test Method for Mechanical Hydrogen Embrittle- 130°C for a minimum of1hto improve adhesion on
ment Evaluation of Plating Processes and Service Environ- heat-treatable (age-hardened) aluminum alloys and carburized
ments steels (see 7.2.4).
2.2 Aerospace Materials Specifications: 4.2.5 Class 5—Parts are heat treated after plating at 365 to
AMS 2399 Electroless Nickel-Boron Plating 375°C for a minimum of4hto improve adhesion on titanium
AMS 2433 Electroless Nickel-Thallium-Boron Plating and titanium alloys (see 7.2.4).
2.3 U.S. Government Standards: 4.3 The classification by grade establishes the minimum
MIL-STD-105 Sampling Procedures and Tables for Inspec- thickness of the coating:
tion by Attributes 4.3.1 Grade A—Parts are plated to a minimum coating
MIL-STD-13165 Shot Peening of Metal Parts thickness of 0.5 µm.
4.3.2 Grade B—Parts are plated to a minimum coating
3. Terminology
thickness of 12 µm.
4.3.3 Grade C—Parts are plated to a minimum coating
3.1 Definitions—Many terms used in this standard are
defined in Terminology B 374. thickness of 25 µm.
4.3.4 Grade D—Parts are plated to a minimum coating
3.2 Definitions of Terms Specific to This Standard:
3.2.1 cold shut—a void on the surface which has been thickness of 75 µm.
closed by machining and then partially opened through clean-
5. Ordering Information
ing.
5.1 The purchaser should be aware of several processing
3.2.2 hot halide stress-corrosion cracking—a type of me-
considerations or options available to the processor and when
chanical failure produced by halogenated solvents that have
ordering should supply the information described in 5.1.1
been absorbed onto titanium and then in the presence of heat
through 5.1.15 in the purchase order and drawings.
cause microcracking, and the loss of mechanical strength.
5.1.1 Title, ASTM designation, and year of issue of this
3.2.3 lap cracks—a surface imperfection caused by cold
specification.
working of steels producing a void which can be duplicated in
5.1.2 Composition and metallurgical condition of the basis
the deposit.
metal, assemblies of dissimilar materials must be identified.
3.2.4 significant surface—those substrate surfaces which
5.1.3 Classification of the coating: type, class, and grade for
the coating must protect and that are essential to the appear-
this specification (see Section 4).
ance.
5.1.4 Minimum thickness required on the significant sur-
4. Classification face, and any maximum dimensions or tolerance requirements,
if any (see 7.2.2).
4.1 The classification by type of these coatings establishes
5.1.5 Method of adhesion testing from Test Method B 571
the amount of boron in the alloy.
to be used in acceptance requirements (see 8.3).
4.1.1 Type 1—Coatings shall contain 0.1 to less than 3.5
5.1.6 Requirements for certification and test reports (see
mass percent boron with the balance nickel.
Section 11).
4.1.2 Type 2—Coatings shall contain 3.5 to 6 mass percent
5.1.7 Requirements for heat treatment of the part(s) for
boron and a minimum of 90 mass percent nickel.
stress relief prior to plating (see 7.2.4).
4.2 The classification by class of these coatings establishes
5.1.8 Optionalsamplingplanforlotinspectionofthepart(s)
the post treatment to be performed on the part(s). The post
(see 9.1 and 13.1).
treatment steps are designed to reduce the potential for
5.1.9 Increased sampling frequency, if any, for qualification
hydrogen embrittlement, increase the adhesion of the coating
tests (see 7.3).
to the substrate, improve the fatigue properties of the part(s),
5.1.10 Supplemental requirements for shot peening of the
and increase the wear resistance and hardness of the coating:
part(s) (see 12.1).
5.1.11 Supplementalrequirementsforweartesting(see12.2
4 and 12.3).
Annual Book of ASTM Standards, Vol 05.01.
5.1.12 Supplemental requirements for heat treatment in
Discontinued; see 1994 Annual Book of ASTM Standards, Vol 03.05.
Annual Book of ASTM Standards, Vol 15.03.
vacuum or inert or reducing atmosphere (see 7.2.1 & 12.4).
Available from Society of Automotive Engineers, Inc. (SAE), 400 Common-
5.1.13 Supplemental contact resistance requirements (see
wealth Drive, Warrendale, PA 15096.
12.5).
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. 5.1.14 Supplemental solderability requirements (see 12.6).
B 607 – 91 (2003)
5.1.15 Supplemental U.S. Government requirements, if any 7.2.3 Adhesion—The coating shall pass the adhesion test of
(see Section 13). Test Method B 571 as specified in the ordering information
(see 5.1.15).
6. Materials and Manufacture 7.2.4 Heat Treatment:
7.2.4.1 All steel part(s) with a tensile strength of 1000 MPa
6.1 Pretreatment—Parts can be processed in accordance
or greater shall be heat treated at 190 6 15°C for stress relief
with Practice B 656.
in accordance with Table 1 before plating and baked within 3
6.1.1 A suitable method should be used to remove surface
h after plating for hydrogen embrittlement relief.
oxides and foreign materials which can cause poor adhesion
7.2.4.2 Class 2 coated part(s) shall be heat treated after
and increased porosity.
plating in accordance with Table 2 for precipitation hardening
6.1.2 A suitable method should be used to condition and
of the deposit.
activate the surface so that an adherent coating will be
7.2.4.3 Heat treatment for Class 3 coated steel part(s) shall
produced.
be in accordance with Table 1.
6.2 Basis Material and Workmanship— Nickel boron coat-
7.2.4.4 Heat treatment for Class 4 and 5 coated part(s) other
ings will replicate the surface finish of the basis material.
than steel basis material shall be in accordance with Table 3.
Imperfections in the surface of the basis material including
7.3 Qualification Requirements—Coating and process at-
scratches, porosity, pits, inclusions, roll and die marks, lap
tributes that require testing on a monthly basis, or more
crack, burrs, cold shuts, and surface roughness that could
frequently when specified in the ordering information by the
adversely affect the coating should be brought to the attention
purchaser. A test specimen or part, processed in a manner that
of the purchaser prior to processing (see 7.2.1).
duplicates the characteristics of production parts, shall be
6.3 Stress Relief—Surface-hardened parts can require stress
produced and used in these tests.
reliefbeforeplating.Thestressreliefheattreatmentcanreduce
7.3.1 Hardness—ThehardnessoftheType2,Class2,Grade
the hardness of some alloys and should therefore be reviewed
CandDcoatingshallbenotlessthan1000HK asmeasured
by all parties before processing (see 5.1.7 and 7.2.4). Shorter
by Test Method B 578.
times and higher temperature can be used if the resulting loss
7.3.2 Composition—The coating composition produced
of surface hardness is acceptable to the purchaser.
from the process shall be analyzed for nickel and boron. The
6.4 Hydrogen Embrittlement Relief— Hydrogen embrittle-
alloy produced shall be within the range specified for the
mentofhighstrengthsteelscanbeinitiatedbyseveraldifferent
coating type.
processing operations. Exposure of the parts to hydrogen
7.3.3 Hydrogen Embrittlement—The process and coating
sources will generally induce the condition. Care must be
shall be evaluated for freedom from hydrogen embrittlement
exercised whenever high strength steel is processed to ensure
and pass requirements of Test Method F 519.
minimal exposure and timely relief treatment.
8. Test Methods
6.5 Stress-Corrosion Cracking—Titanium and titanium al-
loys are subject to stress-corrosion cracking after processing.
8.1 Test Specimens:
Pretreatment solutions including rinses should not contain
8.1.1 When separate test specimens are required, the num-
methanol, halogenated hydrocarbon, or more than 50 ppm
ber to be used, the material from which they are to be made,
chlorides, all of which can cause subsequent stress-corrosion
and their shape and size shall be specified by the purchaser.
cracking when the parts are heated to 260°C or higher.
8.1.2 When separate test specimens are used for acceptance
or qualification testing of the coating, the specimens shall be
7. Requirements
made of the same material as the part(s), have the same
metallurgical condition as the part(s), and be processed with
7.1 Process—The nickel boron coatings shall be produced
the part(s).
by autocatalytic nickel deposition from aqueous solutions.
8.2 Thickness—The thickness shall be measured at any
7.2 Acceptance Requirements—The acceptance require-
place on the significant surface designated by the purchaser,
ments in 7.2.1 through 7.2.4 are required for all lots of part(s).
and the measurement shall be made with an accuracy of better
Each lot of part(s) shall be sampled with the recommended
than 10 % by a method selected by the purchaser. Fig. X1
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