ASTM B607-91(2009)
(Specification)Standard Specification for Autocatalytic Nickel Boron Coatings for Engineering Use
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 specificationdescribes 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 values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.10 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.
X2.1.1 This test method will evaluate the resistance of the coating to abrasive wear. The test is performed on a rotating plated panel that is abraded by two rotating rubber wheels. The panel is weighed before...
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Designation:B607 −91(Reapproved 2009)
Standard Specification for
Autocatalytic Nickel Boron Coatings for Engineering Use
This standard is issued under the fixed designation B607; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope boron with a hardness of about 700 HKN. When the deposit is
heated above 300°C the nickel crystallizes, forming nickel
1.1 Nickel boron coatings are produced by autocatalytic
clusters of Ni (111) and boron precipitates as nickel boride,
(electroless) deposition from aqueous solutions. These solu-
Ni B (211) and (311), increasing the hardness to greater than
tions contain either an alkylamineborane or sodium borohy-
1000 HK for Type 2 coatings.
dride as a reducing agent, a source of nickel ions, a buffer,
complexant, and control chemicals. 1.7 The nickel boron coatings are microporous and offer
limited corrosion protection. Their columnar structure,
1.2 This specification describes the requirements for coat-
however, is beneficial in reducing wear because it provides a
ings of autocatalytic nickel boron deposited from aqueous
means of trapping lubricants within the surface of the coated
solutions onto substrates for engineering use.The specification
part.
classifies these coatings into two types:
1.2.1 Type 1 coatings have a boron content of 0.1 to less 1.8 Thisdocumentdescribesonlyautocatalyticnickelboron
than 3.5 mass percent with the balance nickel. coatings that have been produced without use of external
1.2.2 Type 2 coatings have a boron content of 3.5 to 6 mass electric sources.
percent and a minimum of 90 mass percent nickel.
1.9 The values stated in SI units are to be regarded as
1.3 The coatings are hard and uniform in thickness, even on standard. No other units of measurement are included in this
irregularshapedparts,andusedinawiderangeofapplications. standard.
1.10 The following hazards caveat pertains only to the Test
1.4 Process solutions formulated with an alkylamineborane
Methods section of this specification: This standard does not
usually produce coatings that contain 0.1 to 3.5 % boron. Thin
purport to address the safety problems associated with its use.
coatings of this type provide bondability and solderability on
It is the responsibility of the user of this standard to establish
electronic components such as lead frames, electrical contacts,
appropriate safety and health practices and determine the
and headers. To maintain solderability, these coatings are
applicability of regulatory limitations prior to use.
generally not heat treated.
1.5 Process solutions formulated with sodium borohydride NOTE 1—The followingAMS standards are not requirements. They are
referenced for information only: AMS 2399 and AMS 2433.
are strongly alkaline and are frequently used to plate steel and
titanium parts to impart surface hardness and wear resistance
2. Referenced Documents
properties.Depositsproducedfromtheseprocessescancontain
2.1 ASTM Standards:
3 to 5 % boron and thallium or other metals which are used to
B374 Terminology Relating to Electroplating
stabilizetheplatingsolutionandmodifythecoatingproperties.
B487 Test Method for Measurement of Metal and Oxide
1.6 The physical and mechanical properties of these depos-
Coating Thickness by Microscopical Examination of
itssuchasdensity,hardness,stress,andmeltingpointwillvary
Cross Section
with the boron content. The variation of boron content also
B567 Test Method for Measurement of Coating Thickness
affects the quantity and structure of nickel boride precipitated
by the Beta Backscatter Method
during heat treatment. In the as-plated condition the deposit
B568 Test Method for Measurement of Coating Thickness
consists of a predominantly amorphous mixture of nickel and
by X-Ray Spectrometry
B571 Practice for Qualitative Adhesion Testing of Metallic
Coatings
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee
B08.03 on Engineering Coatings. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 1, 2009. Published November 2009. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1991. Last previous edition approved in 2008 as B607 – 91 (2008). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/B0607-91R09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B607−91 (2009)
B578 Test Method for Microhardness of Electroplated Coat- 4.1.1 Type 1—Coatings shall contain 0.1 to less than 3.5
ings mass percent boron with the balance nickel.
B602 Test Method for Attribute Sampling of Metallic and 4.1.2 Type 2—Coatings shall contain 3.5 to 6 mass percent
Inorganic Coatings boron and a minimum of 90 mass percent nickel.
B656 Guide for Autocatalytic (Electroless) Nickel-
4.2 The classification by class of these coatings establishes
Phosphorus Deposition on Metals for Engineering Use
the post treatment to be performed on the part(s). The post
(Discontinued 2000) (Withdrawn 2000)
treatment steps are designed to reduce the potential for
B667 Practice for Construction and Use of a Probe for
hydrogen embrittlement, increase the adhesion of the coating
Measuring Electrical Contact Resistance
to the substrate, improve the fatigue properties of the part(s),
B678 Test Method for Solderability of Metallic-Coated
and increase the wear resistance and hardness of the coating:
Products
4.2.1 Class 1—Partsaresuppliedasplatedwithnopostheat
B697 Guide for Selection of Sampling Plans for Inspection
treatment.
of Electrodeposited Metallic and Inorganic Coatings
4.2.2 Class 2—Partsareheattreatedafterplatingtoincrease
B762 Test Method of Variables Sampling of Metallic and
hardness. The coating is heat treated at 365 to 385°C for 90
Inorganic Coatings
min (see 7.2.4).
D2670 Test Method for Measuring Wear Properties of Fluid
4.2.3 Class 3—Parts are heat treated after plating at 180 to
Lubricants (Falex Pin and Vee Block Method)
200°C for 2 to 23 h to improve coating adhesion on steel and
D2714 Test Method for Calibration and Operation of the
for hydrogen embrittlement relief of steels (see 7.2.4).
Falex Block-on-Ring Friction and Wear Testing Machine
4.2.4 Class 4—Parts are heat treated after plating at 120 to
E39 Methods for Chemical Analysis of Nickel (Withdrawn
130°C for a minimum of1hto improve adhesion on
1995)
heat-treatable (age-hardened) aluminum alloys and carburized
F519 Test Method for Mechanical Hydrogen Embrittlement
steels (see 7.2.4).
Evaluation of Plating/Coating Processes and Service En-
4.2.5 Class 5—Parts are heat treated after plating at 365 to
vironments
375°C for a minimum of4hto improve adhesion on titanium
2.2 Aerospace Materials Specifications:
and titanium alloys (see 7.2.4).
AMS 2399 Electroless Nickel-Boron Plating
4.3 The classification by grade establishes the minimum
AMS 2433 Electroless Nickel-Thallium-Boron Plating
thickness of the coating:
2.3 U.S. Government Standards:
4.3.1 Grade A—Parts are plated to a minimum coating
MIL-STD-105 Sampling Procedures and Tables for Inspec-
thickness of 0.5 µm.
tion by Attributes
4.3.2 Grade B—Parts are plated to a minimum coating
MIL-STD-13165 Shot Peening of Metal Parts
thickness of 12 µm.
3. Terminology
4.3.3 Grade C—Parts are plated to a minimum coating
thickness of 25 µm.
3.1 Definitions: Many terms used in this specificationare
4.3.4 Grade D—Parts are plated to a minimum coating
defined in Terminology B374.
thickness of 75 µm.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 cold shut—a void on the surface which has been
5. Ordering Information
closed by machining and then partially opened through clean-
5.1 The purchaser should be aware of several processing
ing.
considerations or options available to the processor and when
3.2.2 hot halide stress-corrosion cracking—a type of me-
ordering should supply the information described in 5.1.1
chanical failure produced by halogenated solvents that have
through 5.1.15 in the purchase order and drawings.
been absorbed onto titanium and then in the presence of heat
5.1.1 Title, ASTM designation, and year of issue of this
cause microcracking, and the loss of mechanical strength.
specification.
3.2.3 lap cracks—a surface imperfection caused by cold
5.1.2 Composition and metallurgical condition of the basis
working of steels producing a void which can be duplicated in
metal, assemblies of dissimilar materials must be identified.
the deposit.
5.1.3 Classification of the coating: type, class, and grade for
this specification (see Section 4).
3.2.4 significantsurface—thosesubstratesurfaceswhichthe
5.1.4 Minimum thickness required on the significant
coating must protect and that are essential to the appearance.
surface, and any maximum dimensions or tolerance
4. Classification
requirements, if any (see 7.2.2).
4.1 The classification by type of these coatings establishes 5.1.5 MethodofadhesiontestingfromTestMethodB571to
be used in acceptance requirements (see 8.3).
the amount of boron in the alloy.
5.1.6 Requirements for certification and test reports (see
Section 11).
The last approved version of this historical standard is referenced on
www.astm.org.
5.1.7 Requirements for heat treatment of the part(s) for
Available from Society of Automotive Engineers (SAE), 400 Commonwealth
stress relief prior to plating (see 7.2.4).
Dr., Warrendale, PA 15096-0001, http://www.sae.org.
5.1.8 Optionalsamplingplanforlotinspectionofthepart(s)
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. (see 9.1 and 13.1).
B607−91 (2009)
5.1.9 Increased sampling frequency, if any, for qualification 7.2.1 Appearance—The coating shall have a uniform ap-
tests (see 7.3). pearance without visible imperfections such as blisters, pits,
5.1.10 Supplemental requirements for shot peening of the pimples, and cracks.
part(s) (see 12.1). 7.2.1.1 Imperfections that arise from the surface condition
of the basis metal and that cannot be removed using conven-
5.1.11 Supplementalrequirementsforweartesting(see12.2
and 12.3). tional metal finishing techniques and that persist in the coating
shall not be cause for rejection.
5.1.12 Supplemental requirements for heat treatment in
vacuum or inert or reducing atmosphere (see 7.2.1 & 12.4). 7.2.1.2 Discoloration caused by heat treatment shall not be
cause for rejection unless specified in the ordering information
5.1.13 Supplemental contact resistance requirements (see
12.5). (see 5.1.12 and 12.4).
7.2.2 Thickness—The coating thickness shall be measured
5.1.14 Supplemental solderability requirements (see 12.6).
and conform to the specified grade.
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).
TestMethodB571asspecifiedintheorderinginformation(see
5.1.15).
6. Materials and Manufacture
7.2.4 Heat Treatment:
6.1 Pretreatment—Parts can be processed in accordance
7.2.4.1 All steel part(s) with a tensile strength of 1000 MPa
with Practice B656.
or greater shall be heat treated at 190 6 15°C for stress relief
6.1.1 A suitable method should be used to remove surface
in accordance with Table 1 before plating and baked within 3
oxides and foreign materials which can cause poor adhesion
h after plating for hydrogen embrittlement relief.
and increased porosity.
7.2.4.2 Class 2 coated part(s) shall be heat treated after
6.1.2 A suitable method should be used to condition and
plating in accordance with Table 2 for precipitation hardening
activate the surface so that an adherent coating will be
of the deposit.
produced.
7.2.4.3 Heat treatment for Class 3 coated steel part(s) shall
6.2 Basis Material and Workmanship—Nickel boron coat-
be in accordance with Table 1.
ings will replicate the surface finish of the basis material.
7.2.4.4 Heat treatment for Class 4 and 5 coated part(s) other
Imperfections in the surface of the basis material including
than steel basis material shall be in accordance with Table 3.
scratches, porosity, pits, inclusions, roll and die marks, lap
7.3 Qualification Requirements—Coating and process attri-
crack, burrs, cold shuts, and surface roughness that could
butes that require testing on a monthly basis, or more fre-
adversely affect the coating should be brought to the attention
quently when specified in the ordering information by the
of the purchaser prior to processing (see 7.2.1).
purchaser. A test specimen or part, processed in a manner that
6.3 Stress Relief—Surface-hardened parts can require stress duplicates the characteristics of production parts, shall be
reliefbeforeplating.Thestressreliefheattreatmentcanreduce
produced and used in these tests.
the hardness of some alloys and should therefore be reviewed 7.3.1 Hardness—ThehardnessoftheType2,Class2,Grade
by all parties before processing (see 5.1.7 and 7.2.4). Shorter CandDcoatingshallbenotlessthan1000HK asmeasured
times and higher temperature can be used if the resulting loss by Test Method B578.
of surface hardness is acceptable to the purchaser. 7.3.2 Composition—The coating composition produced
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 F519.
minimal exposure and timely relief treatment.
6.5 Stress-Corrosion Cracking—Titanium and titanium al-
8. Test Methods
loys are subject to stress-corrosion cracking after processing.
8.1 Test Specimens:
Pretreatment solutions including rinses should not contain
methanol, halogenated hydrocarbon, or more than 50 ppm
chlorides, all of which can cause subsequent stress-corrosion
cracking when the parts are heated to 260°C or higher.
TABLE 1 Heat Treatment for Stress Relief Before Plating and for
Hydrogen Embrittlement Relief After Plating
7. Re
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