ASTM B530-02
(Test Method)Standard Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Electrodeposited Nickel Coatings on Magnetic and Nonmagnetic Substrates
Standard Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Electrodeposited Nickel Coatings on Magnetic and Nonmagnetic Substrates
SIGNIFICANCE AND USE
The thickness of a coating is often critical to its performance. This magnetic method is suitable for measuring nondestructively the thickness of some nickel coatings and for specification acceptance.
This method requires that the magnetic properties of the coating and its substrate be the same as those of the calibration standards.
SCOPE
1.1 This test method covers the use of magnetic instruments for the nondestructive measurement of the thickness of an electrodeposited nickel coating on either a magnetic or nonmagnetic substrate.
1.2 These instruments measure either the magnetic attraction between a magnet and the coating-substrate combination, or the reluctance of a magnetic flux path passing through the coating and the basis metal.
1.3 For this test method, there are two types of coating-substrate combinations that can be encountered: Type A, nickel coatings on a magnetic substrate, and Type B, nickel coatings on a nonmagnetic substrate.
1.4 The effective measuring ranges of instruments using the principle of magnetic attraction are up to 50 m for Type A coatings, and up to 25 m for Type B coatings. For reluctance gages, the effective ranges are much greater, and measurements up to 1 mm or more, can be made on both types of coatings.
1.5 Measurements made in accordance with this test method will be in compliance with the requirements of ISO Standard 2361 as printed in 1982.
1.6 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:B530 –02
Standard Test Method for
Measurement of Coating Thicknesses by the Magnetic
Method: Electrodeposited Nickel Coatings on Magnetic and
1
Nonmagnetic Substrates
This standard is issued under the fixed designation B 530; 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 3. Significance and Use
1.1 This test method covers the use of magnetic instruments 3.1 The thickness of a coating is often critical to its
for the nondestructive measurement of the thickness of an performance. This magnetic method is suitable for measuring
electrodeposited nickel coating on either a magnetic or non- nondestructively the thickness of some nickel coatings and for
magnetic substrate. specification acceptance.
1.2 These instruments measure either the magnetic attrac- 3.2 This method requires that the magnetic properties of the
tion between a magnet and the coating-substrate combination, coating and its substrate be the same as those of the calibration
or the reluctance of a magnetic flux path passing through the standards.
coating and the basis metal.
4. Factors Affecting the Measuring Accuracy
1.3 For this test method, there are two types of coating-
4.1 Coating Thickness—Inherent in the method is a mea-
substrate combinations that can be encountered:TypeA, nickel
coatings on a magnetic substrate, and Type B, nickel coatings suring uncertainty that, for thin coatings, is constant and
independent of the coating thickness; for thicknesses greater
on a nonmagnetic substrate.
1.4 The effective measuring ranges of instruments using the thanabout50µm,thisuncertaintyisproportionaltothecoating
thickness.
principle of magnetic attraction are up to 50 µm for Type A
coatings, and up to 25 µm for Type B coatings. For reluctance 4.2 Magnetic Properties of the Basis Metal (Type A coat-
ings only)—Magnetic thickness measurements are affected by
gages,theeffectiverangesaremuchgreater,andmeasurements
variations in the magnetic properties of the basis metal. For
up to 1 mm or more, can be made on both types of coatings.
1.5 Measurementsmadeinaccordancewiththistestmethod practical purposes, magnetic variations in low-carbon steel can
often be considered to be insignificant. To avoid the influences
will be in compliance with the requirements of ISO Stan-
dard 2361 as printed in 1982. of severe or localized heat treatments and cold working, the
instrument should be calibrated using a calibration standard
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the having a basis metal with the same magnetic properties as that
of the test specimen or, preferably and if available, with a
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- sampleoftheparttobetestedbeforeapplicationofthecoating.
4.3 Basis Metal Thickness (Type A coatings only)—For
bility of regulatory limitations prior to use.
each instrument, there is a critical thickness of the basis metal
2. Referenced Documents
above which the measurements will not be affected by an
2.1 ISO International Standard: increase in that thickness. Since it depends on the instrument
ISO 2361 Electrodeposited Nickel Coatings on Magnetic probe (Note 1) and the nature of the basis metal, its value
and Nonmagnetic Substrates—Measurement of Coating should be determined experimentally, if it is not supplied by
2
Thickness—Magnetic Method the manufacturer.
NOTE 1—Theterm“instrumentprobe”alsoincludestheterm“magnet.”
1
This test method is under the jurisdiction ofASTM Committee B08 on Metallic
4.4 Edge Effect—The method is sensitive to abrupt changes
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on
in the surface contour of the test specimen. Therefore, mea-
General Test Methods.
surements made too near an edge or inside corner will not be
Current edition approved Sept. 10, 2002. Published November 2002. Originally
published as B 530 – 70. Last previous edition B 530 – 96.
valid, unless the instrument is specially calibrated for such a
2
Available from American National Standards Institute, 11 W. 42nd St., 13th
measurement. This also applies to measurements made on
Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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B530 –02
geometrically limited areas, such as narrow conductors on same compositi
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