ASTM B659-90(2021)

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: B659 − 90 (Reapproved 2021)
Standard Guide for
Measuring Thickness of Metallic and Inorganic Coatings
This standard is issued under the fixed designation B659; 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 by the Magnetic Method: Nonmagnetic Coatings on
Magnetic Basis Metals
1.1 This guide covers the methods for measuring the thick-
B504 Test Method for Measurement of Thickness of Metal-
ness of many metallic and inorganic coatings including
lic Coatings by the Coulometric Method
electrodeposited, mechanically deposited, vacuum deposited,
B530 Test Method for Measurement of Coating Thicknesses
anodic oxide, and chemical conversion coatings.
by the Magnetic Method: Electrodeposited Nickel Coat-
1.2 This guide is limited to tests considered in ASTM
ings on Magnetic and Nonmagnetic Substrates
standardsanddoesnotcovercertainteststhatareemployedfor
B567 Test Method for Measurement of Coating Thickness
special applications.
by the Beta Backscatter Method
B568 Test Method for Measurement of Coating Thickness
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this by X-Ray Spectrometry
B588 Test Method for Measurement of Thickness of Trans-
standard.
parent or Opaque Coatings by Double-Beam Interference
1.4 This standard does not purport to address all of the
Microscope Technique (Withdrawn 2016)
safety concerns, if any, associated with its use. It is the
B681 Test Method for Measurement of Thickness ofAnodic
responsibility of the user of this standard to establish appro-
CoatingsonAluminumandofOtherTransparentCoatings
priate safety, health, and environmental practices and deter-
on Opaque Surfaces Using the Light-Section Microscope
mine the applicability of regulatory limitations prior to use.
(Withdrawn 2001)
1.5 This international standard was developed in accor-
B767 Guide for Determining Mass Per Unit Area of Elec-
dance with internationally recognized principles on standard-
trodeposited and Related Coatings by Gravimetric and
ization established in the Decision on Principles for the
Other Chemical Analysis Procedures
Development of International Standards, Guides and Recom-
2.2 ISO Standards:
mendations issued by the World Trade Organization Technical
1463 Metal and Oxide Coatings—Measurement of Thick-
Barriers to Trade (TBT) Committee.
ness by Microscopic Examination of Cross Sections
2. Referenced Documents 2128 Surface Treatment of Metals—Anodization (Anodic
Oxidation) ofAluminum and ItsAlloys—Measurement of
2.1 ASTM Standards:
the Thickness of Oxide Coatings—Nondestructive Mea-
B244 Test Method for Measurement of Thickness ofAnodic
surement by Light Section Microscope
Coatings on Aluminum and of Other Nonconductive
2176 Petroleum Products Lubricating Grease Determination
Coatings on Nonmagnetic Basis Metals with Eddy-
of Dropping Point
Current Instruments
2177 Metallic Coatings—Measurement of Coating
B487 Test Method for Measurement of Metal and Oxide
Thickness—Coulometric Method by Anodic Solution
Coating Thickness by Microscopical Examination of
2178 Non-Magnetic Metallic and Vitreous or Porcelain
Cross Section
EnamelCoatingsonMagneticBasisMetals,Measurement
B499 Test Method for Measurement of Coating Thicknesses
of Coating Thickness, Magnetic Method
2360 Non-Conductive Coatings on Non-Magnetic Basis
Metals—Measurement of Coating Thickness—Eddy Cur-
This guide is under the jurisdiction of ASTM Committee B08 on Metallic and
Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on Test
rent Method
Methods.
2361 Electrodeposited Nickel Coatings on Magnetic and
Current edition approved April 1, 2021. Published May 2021. Originally
approved in 1979. Last previous edition approved in 2014 as B659–90(2014). DOI:
10.1520/B0659-90R21.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
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B659 − 90 (2021)
Non-Magnetic Substrates—Measurement of Coating material and on the equipment used. When exposed to X rays,
Thickness—Magnetic Method the intensity of the secondary radiation emitted by the coating
3497 Metallic Coatings—Measurement of Coating or by the substrate followed by attenuation by the coating is
Thickness—X-Ray Spectrometric Methods measured.Theintensityofthesecondaryradiationisafunction
3543 Metallic and Non-Metallic Coatings—Measurement of of the coating thickness.
Thickness—Beta Backscatter Method 5.3.2 In multiple coatings the X-ray method is generally
applicable to the final metal coating.
3. Significance and Use
5.3.3 Suitable equipment is available commercially (Test
Method B568 and ISO 3497).
3.1 Most coating specifications specify the thickness of the
coating because coating thickness is often an important factor
5.4 Beta Backscatter Method:
in the performance of the coating in service.
5.4.1 The beta backscatter method employs radioisotopes
that emit beta radiation and a detector that measures the
3.2 The methods included in this guide are suitable for
intensity of the beta radiation backscattered by the test speci-
acceptance testing and are to be found in ASTM standards.
men. Part of the beta radiation entering the material collides
3.3 Each method has its own limitations with respect to the
with atoms of the material and is scattered back towards the
kind of coating and its thickness.
source. The intensity of the backscattered radiation is a
function, among others, of the coating thickness. A measure-
4. Reliability of Methods
ment is possible if the atomic number of the coating material is
4.1 All methods covered by this guide are sufficiently
sufficiently different from that of its substrate and if the beta
reliable to be used for acceptance testing of many electroplated
radiationisofsuitableenergyandintensity.Themethodcanbe
and other coatings. That is, each method is capable of yielding
used for measuring both thin and thick coatings, the maximum
measurements with an uncertainty of less than 10 % of the
thicknessbeingafunctionoftheatomicnumberofthecoating.
coating thickness over a significant range of coating thick-
In practice, high atomic number coatings, such as gold, can be
nesses when used by properly instructed personnel.
measured up to 50 µm, while low atomic number coatings,
such as copper or nickel, can be measured up to about 200 µm.
5. Nondestructive Methods
5.4.2 Coating thickness gages of this type are available
5.1 MagneticMethods—Thesemethodsemployinstruments
commercially (Test Method B567 and ISO 3543).
that measure the magneti
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