ASTM B490-92(2008)e1
(Practice)Standard Practice for Micrometer Bend Test for Ductility of Electrodeposits
Standard Practice for Micrometer Bend Test for Ductility of Electrodeposits
SIGNIFICANCE AND USE
This practice is useful as one method of controlling some electroplating solutions. It serves to indicate the presence of contamination or some other adverse condition.
Ductility measurements are of particular value when electroplated parts are to be subjected to moderate stress such as that involved in bolting an electroplated bumper to an automobile.
Note 1—The foils used in this practice are typically 25 to 40 μm thick. Foils in this thickness range do not have the same properties as bulk metal. For example, a nickel electrodeposit 0.5 mm thick, prepared in purified bright nickel electroplating solutions for which this test is being used, had less than 3 % elongation in a tension test, and could not be bent to a 90° angle without complete fracture. However, foils 25 to 40 μm thick, electroplated at the same time, had micrometer ductility values in the 10 to 25 % range.
SCOPE
1.1 This practice describes a procedure for measuring the ductility of electrodeposited foils.
1.2 This practice is suitable only for the evaluation of electrodeposits having low ductility.
1.3 The obtained ductility values must only be considered semi-quantitative because this test has a significant operator dependence.
1.4 This practice is best used for in-house process control where measurements are always made by the same operator. A change in ductility value can be used as an indication of possible changes in the electroplating solution.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address the safety problems, 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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e1
Designation:B490–92(Reapproved2008)
Standard Practice for
Micrometer Bend Test for Ductility of Electrodeposits
This standard is issued under the fixed designation B 490; 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.
e NOTE—The units statement in subsection 1.5 was corrected editorially in April 2008.
1. Scope 4. Significance and Use
1.1 This practice describes a procedure for measuring the 4.1 This practice is useful as one method of controlling
ductility of electrodeposited foils. some electroplating solutions. It serves to indicate the presence
1.2 This practice is suitable only for the evaluation of of contamination or some other adverse condition.
electrodeposits having low ductility. 4.2 Ductility measurements are of particular value when
1.3 The obtained ductility values must only be considered electroplated parts are to be subjected to moderate stress such
semi-quantitative because this test has a significant operator as that involved in bolting an electroplated bumper to an
dependence. automobile.
1.4 This practice is best used for in-house process control
NOTE 1—The foils used in this practice are typically 25 to 40 µm thick.
where measurements are always made by the same operator.A
Foilsinthisthicknessrangedonothavethesamepropertiesasbulkmetal.
change in ductility value can be used as an indication of
For example, a nickel electrodeposit 0.5 mm thick, prepared in purified
possible changes in the electroplating solution.
bright nickel electroplating solutions for which this test is being used, had
less than 3 % elongation in a tension test, and could not be bent to a 90°
1.5 The values stated in SI units are to be regarded as
angle without complete fracture. However, foils 25 to 40 µm thick,
standard. No other units of measurement are included in this
electroplated at the same time, had micrometer ductility values in the 10
standard.
to 25 % range.
1.6 This standard does not purport to address the safety
problems, if any, associated with its use. It is the responsibility
5. Apparatus
of the user of this standard to establish appropriate safety and
5.1 Micrometer, 25-mm with flat jaws to measure the
health practices and determine the applicability of regulatory
thickness and to compress the foil.
limitations prior to use.
5.2 Hand or Power Shear, grinding wheel, or hack saw, to
trimtheedgesoftheelectroplatedpanelandtoseparatethefoil
2. Referenced Documents
from the basis metal.
2.1 ASTM Standards:
5.3 Pair of Sharp Scissors to cut the test specimens.
B 177 Guide for Engineering Chromium Electroplating
6. Test Specimens
3. Summary of Practice
6.1 An electrodeposit shall be prepared using a basis metal
3.1 This practice consists of measuring the bend of a foil
with a smooth surface from which the electrodeposit can be
held between the jaws of a micrometer; these are closed until
readily separated.Astainless steel or nickel electroplated steel
fracture or cracks appear.
panel may be used for this purpose, prepared as in 6.2.
6.2 Apieceofcold-rolledsteel,ofanyconvenientsize,such
as 100 by 150 mm, shall be properly cleaned, acid dipped, and
electroplated with approximately 7.5 µm of nickel. After
This practice is under the jurisdiction of ASTM Committee B08 on Metallic
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on
rinsing, the specimen shall be cleaned anodically for 15 s in a
Test Methods.
hot alkaline cleaner, rinsed, acid dipped in about 1 Nsulfuric
Current edition approved April 1, 2008. Published April 2008. Originally
acid (about 27 mLof concentrated sulfuric acid added to about
approved in 1968. Last previous edition approved in 2003 as B 490 – 92 (2003).
900 mL of cold water, mixed, and diluted with cold water to 1
For a discussion of this test see Mohrnheim, A. F., “The Bend Test for
Measuring the Strain Limit of Surfaces,” Plating, Vol 50, 1963, pp. 1094–1099.
L), and immediately placed in the electroplating solution of the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
metal to be tested.An electrodeposit 25 to 40 µm thick shall be
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
electroplated on the prepared surface. The deposit shall be
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. plated at an average current density and under conditions
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