ASTM B578-87(2015)
(Test Method)Standard Test Method for Microhardness of Electroplated Coatings
Standard Test Method for Microhardness of Electroplated Coatings
ABSTRACT
This test method specifies the determination of the microhardness of metallic coatings upon various substrates (electroplated coatings). Measurements shall be made with the Knoop indenter under specified test loads, and the hardness shall be reported as a Knoop hardness number (HK).
SCOPE
1.1 This test method covers the determination of the hardness of metallic coatings upon various substrates. The measurements are made with the Knoop indenter under a test load of 0.245 N (25 gf) or 0.981 N (100 gf).
1.2 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.
General Information
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Designation: B578 − 87 (Reapproved 2015)
Standard Test Method for
1
Microhardness of Electroplated Coatings
This standard is issued under the fixed designation B578; 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 3.1.2 The thickness of the coating shall be at least 38 µm for
soft coatings such as gold, copper, and silver, and 25 µm for
1.1 This test method covers the determination of the hard-
hard coatings such as nickel, cobalt, iron, and hard gold. This
ness of metallic coatings upon various substrates. The mea-
is approximately equivalent to 0.6 times the length of the long
surements are made with the Knoop indenter under a test load
Knoop diagonal.
of 0.245 N (25 gf) or 0.981 N (100 gf).
3.1.3 Make the indentation near the center of the cross
1.2 This standard does not purport to address all of the
section of the coating.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2 No single test load is applicable to all coatings. Use a
priate safety and health practices and determine the applica-
load of 0.245 N for soft coatings (from 50 to 300 HK) and a
bility of regulatory limitations prior to use.
load of 0.981 N for hard coatings (greater than 300 HK).
3.2.1 A load of less than 0.245 N is not recommended.
2. Referenced Documents
However, when the length of the diagonal is great enough at a
2.1 ASTM Standards: load of 0.245 N, which may occur for very soft coatings such
E384 Test Method for Knoop and Vickers Hardness of as tin and indium, a lighter load or a lower magnification shall
2
Materials be specified provided the requirements of 3.3 are met. When
testing extremely hard coatings, a load greater than 0.981 N
3. Special Requirements
may be used provided this is specified in the purchase order.
The Knoop hardness number decreases appreciably with loads
3.1 In addition to the requirements listed herein, the test
from 0.245 N to 0.981 N especially for the higher hardness
method shall be performed in accordance with Test Method
numbers.
E384.
3.1.1 The measurement shall be made on the cross section
3.3 Measure the length of the long diagonal to within 0.25
with the long diagonal of the indentation parallel to the
µmor0.4 %,whicheverislarger,atthemagnificationspecified
substrate using a Knoop indenter.
in Test Method E384.
NOTE 1—When a nondestructive test is necessary, the measurement
3.4 When readings are taken in a direction parallel to the
may be made normal to the surface provided that the whole of the
substrate, space them from each other by at least the length of
indentation is clearly delineated in the field of the microscope at the
thelongdiagonal.Whentworeadingsaretakeninthedirection
magnification specified in Test Method E384, and the coating thickness is
at least 0.7 that of the long diagonal. The outlines of the indentation must
of the short axis, separate them by at least the length of the
be sharp and undistorted by any mechanical effects resulting from the
diagonal perpendicular to the substrate (short diagonal). In
thinness of the coating such as “butterfly” fractures, etc. Values obtained
such cases, the distance from the substrate and from the outer
from measurements made normal to the electroplated surface may not be
surface of the coating to an edge of the indentation shall be at
equivalent to those obtained on microsections and are not, therefore,
least the width of the short diagonal.
reportable according to Section 6.
3.5 If the electroplated coating is cracked, or if cracks or
“butterfly” markings (see 7.2 of Test Method E384) appear
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ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic
when the indentation load is applied or removed, the hardness
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on
measurement is invalid.
Test Methods.
Current edition approved March 1, 2015. Published April 2015. Originally
approved in 1973. Last previous edition approved in 2009 as B578 – 87 (2009).
4. Preparation of Test Specimen
DOI: 10.1520/B0578-87R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.1 Overplate the specimen to a thickness of at least 12 µm
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
with a metal of a contrasting color whose hardness approxi-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. mates that of the coating.
Copyright © ASTM International, 100 Barr Har
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B578 − 87 (Reapproved 2009) B578 − 87 (Reapproved 2015)
Standard Test Method for
1
Microhardness of Electroplated Coatings
This standard is issued under the fixed designation B578; 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
1.1 This test method covers the determination of the hardness of metallic coatings upon various substrates. The measurements
are made with the Knoop indenter under a test load of 0.245 N (25 gf) or 0.981 N (100 gf).
1.2 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.
2. Referenced Documents
2.1 ASTM Standards:
2
E384 Test Method for Knoop and Vickers Hardness of Materials
3. Special Requirements
3.1 In addition to the requirements listed herein, the test method shall be performed in accordance with Test Method E384.
3.1.1 The measurement shall be made on the cross section with the long diagonal of the indentation parallel to the substrate
using a Knoop indenter.
NOTE 1—When a nondestructive test is necessary, the measurement may be made normal to the surface provided that the whole of the indentation is
clearly delineated in the field of the microscope at the magnification specified in Test Method E384, and the coating thickness is at least 0.7 that of the
long diagonal. The outlines of the indentation must be sharp and undistorted by any mechanical effects resulting from the thinness of the coating such
as “butterfly” fractures, etc. Values obtained from measurements made normal to the electroplated surface may not be equivalent to those obtained on
microsections and are not, therefore, reportable according to Section 6.
3.1.2 The thickness of the coating shall be at least 38 μm for soft coatings such as gold, copper, and silver, and 25 μm for hard
coatings such as nickel, cobalt, iron, and hard gold. This is approximately equivalent to 0.6 times the length of the long Knoop
diagonal.
3.1.3 Make the indentation near the center of the cross section of the coating.
3.2 No single test load is applicable to all coatings. Use a load of 0.245 N for soft coatings (from 50 to 300 HK) and a load
of 0.981 N for hard coatings (greater than 300 HK).
3.2.1 A load of less than 0.245 N is not recommended. However, when the length of the diagonal is great enough at a load of
0.245 N, which may occur for very soft coatings such as tin and indium, a lighter load or a lower magnification shall be specified
provided the requirements of 3.3 are met. When testing extremely hard coatings, a load greater than 0.981 N may be used provided
this is specified in the purchase order. The Knoop hardness number decreases appreciably with loads from 0.245 N to 0.981 N
especially for the higher hardness numbers.
3.3 Measure the length of the long diagonal to within 0.25 μm or 0.4 %, whichever is larger, at the magnification specified in
Test Method E384.
3.4 When readings are taken in a direction parallel to the substrate, space them from each other by at least the length of the long
diagonal. When two readings are taken in the direction of the short axis, separate them by at least the length of the diagonal
1
This test method is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on Test
Methods.
Current edition approved Sept. 1, 2009March 1, 2015. Published December 2009April 2015. Originally approved in 1973. Last previous edition approved in 20042009
as B578 – 87 (2004).(2009). DOI: 10.1520/B0578-87R09.10.1520/B0578-87R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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B578 − 87 (2015)
perpendicular to the substrate (short diagonal). In such cases, th
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