ASTM D7187-15
(Test Method)Standard Test Method for Measuring Mechanistic Aspects of Scratch/Mar Behavior of Paint Coatings by Nanoscratching
Standard Test Method for Measuring Mechanistic Aspects of Scratch/Mar Behavior of Paint Coatings by Nanoscratching
SIGNIFICANCE AND USE
4.1 This test attempts to address two major drawbacks in existing mar tests such as Test Methods D1044, D3363, D5178, D6037, and D6279, namely:
4.1.1 Measured damage is caused by hundreds of contacts with differing contact geometries making it difficult or impossible for mechanical quantities (force, displacement) at the contact points to be reliably determined.
4.1.2 The damage is evaluated using subjective visual assessments, which provide only a qualitative sense of wear with little information about mar mechanisms.
4.2 This test provides a quantitative assessment of a paint coating’s mechanistic aspects of scratch/mar behavior in various conditions. The ability to control testing variables such as rate and temperature allow the study of the scratch/mar behavior in a variety of environments.
4.3 This test method is particularly suitable for measurement of paint coatings on laboratory test panels.
4.4 The accuracy and precision of scratch/mar performance may be significantly influenced by surface nonuniformity and irregularities.
4.5 A correlation has been observed between good mar resistance in field studies and a combination of high Plastic Resistance and high Fracture Resistance (terms are defined below). When coatings have had either high Plastic Resistance and low Fracture Resistance, or low Plastic Resistance and high Fracture Resistance, there have been contradictory results in field studies.
4.6 Mar resistance characterizes the ability of the coating to resist light damage. The difference between mar and scratch resistance is that mar is related to only the relatively fine surface scratches which spoil the appearance of the coating. The mechanistic aspects of mar resistance depend on a complex interplay between visco-elastic and thermal recovery, yield or plastic flow, and micro-fracture. Polymers are challenging because they exhibit a range of mechanical properties from near liquid through rubber materials to brittle solids. The mecha...
SCOPE
1.1 This test method covers the nanoscratch method for determining the resistance of paint coatings on smooth flat surfaces to scratch/mar.
1.2 Previous methods used in scratch/mar evaluation first physically scratch or mar a sample’s surface with multiple contact cutting, and then use visual inspection to assign a ranking. It has been recognized that loss of appearance is mainly due to surface damages created. The philosophy of this method is to quantitatively and objectively measure scratch/mar behavior by making the evaluation process two steps with emphasis on surface damages. Step one is to find the relationship between damage shape and size and external input (such as forces, contact geometry, and deformation). Step two is to relate damage shape and size to visual loss of luster. The first step is covered by this method; in addition, a survey in the appendix provides an example of an experiment to relate the damage to the change in luster.
1.3 There are three elementary deformation mechanisms: elastic deformation, plastic deformation and fracture; only the latter two both contribute significantly to mar. This method evaluates scratch/mar based on the latter two damage mechanisms.
1.4 Although this standard was developed for paint coatings, it can also be applied to other types of similar polymer-based coatings, for example, lacquers, varnishes, glazes and other decorative and protective layers deposited on hard substrates.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 This standard does not purport to address all of 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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Designation: D7187 − 15
Standard Test Method for
Measuring Mechanistic Aspects of Scratch/Mar Behavior of
1
Paint Coatings by Nanoscratching
This standard is issued under the fixed designation D7187; 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 priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This test method covers the nanoscratch method for
determining the resistance of paint coatings on smooth flat
2. Referenced Documents
surfaces to scratch/mar.
2
2.1 ASTM Standards:
1.2 Previous methods used in scratch/mar evaluation first
D609 Practice for Preparation of Cold-Rolled Steel Panels
physically scratch or mar a sample’s surface with multiple
for Testing Paint, Varnish, Conversion Coatings, and
contact cutting, and then use visual inspection to assign a
Related Coating Products
ranking. It has been recognized that loss of appearance is
D823 Practices for Producing Films of Uniform Thickness
mainly due to surface damages created. The philosophy of this
of Paint, Varnish, and Related Products on Test Panels
method is to quantitatively and objectively measure scratch/
D1005 Test Method for Measurement of Dry-Film Thick-
mar behavior by making the evaluation process two steps with
ness of Organic Coatings Using Micrometers
emphasis on surface damages. Step one is to find the relation-
D1044 TestMethodforResistanceofTransparentPlasticsto
ship between damage shape and size and external input (such
Surface Abrasion
as forces, contact geometry, and deformation). Step two is to
D3363 Test Method for Film Hardness by Pencil Test
relate damage shape and size to visual loss of luster. The first
D3924 Specification for Environment for Conditioning and
step is covered by this method; in addition, a survey in the
Testing Paint, Varnish, Lacquer, and Related Materials
appendix provides an example of an experiment to relate the
D5178 Test Method for Mar Resistance of Organic Coatings
damage to the change in luster.
D6037 Test Methods for Dry Abrasion Mar Resistance of
1.3 There are three elementary deformation mechanisms:
High Gloss Coatings
elastic deformation, plastic deformation and fracture; only the
D6279 Test Method for Rub Abrasion Mar Resistance of
latter two both contribute significantly to mar. This method
High Gloss Coatings
evaluates scratch/mar based on the latter two damage mecha-
D7091 Practice for Nondestructive Measurement of Dry
nisms.
Film Thickness of Nonmagnetic Coatings Applied to
Ferrous Metals and Nonmagnetic, Nonconductive Coat-
1.4 Although this standard was developed for paint
ings Applied to Non-Ferrous Metals
coatings, it can also be applied to other types of similar
G171 Test Method for Scratch Hardness of Materials Using
polymer-based coatings, for example, lacquers, varnishes,
a Diamond Stylus
glazes and other decorative and protective layers deposited on
hard substrates.
3. Summary of Test Method
1.5 The values stated in SI units are to be regarded as the
3.1 This test method is based on representative samples of
standard. The values given in parentheses are for information
the paint film being scratched using a nanoscratch instrument.
only.
From information received during a scratch test, values for
1.6 This standard does not purport to address all of the
plastic resistance and fracture resistance can be determined.
safety problems, if any, associated with its use. It is the
3.2 From these values of plastic resistance and fracture
responsibility of the user of this standard to establish appro-
resistance, the mechanistic aspects of scratch/mar behavior of
the coating can be subsequently compared.
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
2
Subcommittee D01.23 on Physical Properties of Applied Paint Films. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2015. Published April 2015. Originally contact ASTM Customer Service at service@astm.org. For ASTM Book of ASTM
approved in 2005. Last previous edition approved in 2010 as D7187 – 10. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7187-15. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D7187 − 15
4. Significance and Use instrument should have a maximum normal force of at least 50
mN (mN should be read as
...
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: D7187 − 10 D7187 − 15
Standard Test Method for
Measuring Mechanistic Aspects of Scratch/Mar Behavior of
1
Paint Coatings by Nanoscratching
This standard is issued under the fixed designation D7187; 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
1.1 This test method covers the nanoscratch method for determining the resistance of paint coatings on smooth flat surfaces to
scratch/mar.
1.2 Previous methods used in scratch/mar evaluation first physically scratch or mar a sample’s surface with multiple contact
cutting, and then use visual inspection to assign a ranking. It has been recognized that loss of appearance is mainly due to surface
damages created. The philosophy of this method is to quantitatively and objectively measure scratch/mar behavior by making the
evaluation process two steps with emphasis on surface damages. Step one is to find the relationship between damage shape and
size and external input (such as forces, contact geometry, and deformation). Step two is to relate damage shape and size to visual
loss of luster. The first step is covered by this method; in addition, a survey in the appendix provides an example of an experiment
to relate the damage to the change in luster.
1.3 There are three elementary deformation mechanisms: elastic deformation, plastic deformation and fracture; only the latter
two both contribute significantly to mar. This method evaluates scratch/mar based on the latter two damage mechanisms.
1.4 Although this standard was developed for paint coatings, it can also be applied to other types of similar polymer-based
coatings, for example, lacquers, varnishes, glazes and other decorative and protective layers deposited on hard substrates.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 This standard does not purport to address all of 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D609 Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related Coating
Products
D823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
D1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
D1044 Test Method for Resistance of Transparent Plastics to Surface Abrasion
D1186 Test Methods for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to a Ferrous
3
Base (Withdrawn 2006)
D1400 Test Method for Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to a
3
Nonferrous Metal Base (Withdrawn 2006)
D3363 Test Method for Film Hardness by Pencil Test
D3924 Specification for Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials
D5178 Test Method for Mar Resistance of Organic Coatings
D6037 Test Methods for Dry Abrasion Mar Resistance of High Gloss Coatings
D6279 Test Method for Rub Abrasion Mar Resistance of High Gloss Coatings
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved Dec. 1, 2010Feb. 1, 2015. Published December 2010April 2015. Originally approved in 2005. Last previous edition approved in 20052010 as
D7187 – 05.– 10. DOI: 10.1520/D7187-10.10.1520/D7187-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For ASTM 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
1
---------------------- Page: 1 ----------------------
D7187 − 15
D7091 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals
and Nonmagnetic, Nonconductive Coatings Applied to Non-F
...
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