ASTM D7187-10
(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
This test attempts to address two major drawbacks in existing mar tests such as Test Methods D1044, D3363, D5178, D6037, and D6279, namely:
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.
The damage is evaluated using subjective visual assessments, which provide only a qualitative sense of wear with little information about mar mechanisms.
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.
This test method is particularly suitable for measurement of paint coatings on laboratory test panels.
The accuracy and precision of scratch/mar performance may be significantly influenced by surface nonuniformity and irregularities.
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.
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 mechanical properties are rate and temperature d...
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 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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 − 10
StandardTest 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 2. Referenced Documents
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1.1 This test method covers the nanoscratch method for 2.1 ASTM Standards:
determining the resistance of paint coatings on smooth flat D609 Practice for Preparation of Cold-Rolled Steel Panels
surfaces to scratch/mar. for Testing Paint, Varnish, Conversion Coatings, and
Related Coating Products
1.2 Previous methods used in scratch/mar evaluation first
D823 Practices for Producing Films of Uniform Thickness
physically scratch or mar a sample’s surface with multiple
of Paint, Varnish, and Related Products on Test Panels
contact cutting, and then use visual inspection to assign a
D1005 Test Method for Measurement of Dry-Film Thick-
ranking. It has been recognized that loss of appearance is
ness of Organic Coatings Using Micrometers
mainly due to surface damages created. The philosophy of this
D1044 TestMethodforResistanceofTransparentPlasticsto
method is to quantitatively and objectively measure scratch/
Surface Abrasion
mar behavior by making the evaluation process two steps with
D1186 Test Methods for Nondestructive Measurement of
emphasis on surface damages. Step one is to find the relation-
Dry Film Thickness of Nonmagnetic Coatings Applied to
ship between damage shape and size and external input (such
3
a Ferrous Base (Withdrawn 2006)
as forces, contact geometry, and deformation). Step two is to
D1400 TestMethodforNondestructiveMeasurementofDry
relate damage shape and size to visual loss of luster. The first
Film Thickness of Nonconductive Coatings Applied to a
step is covered by this method; in addition, a survey in the
3
Nonferrous Metal Base (Withdrawn 2006)
appendix provides an example of an experiment to relate the
D3363 Test Method for Film Hardness by Pencil Test
damage to the change in luster.
D3924 Specification for Environment for Conditioning and
1.3 There are three elementary deformation mechanisms:
Testing Paint, Varnish, Lacquer, and Related Materials
elastic deformation, plastic deformation and fracture; only the
D5178 Test Method for Mar Resistance of Organic Coatings
latter two both contribute significantly to mar. This method
D6037 Test Methods for Dry Abrasion Mar Resistance of
evaluates scratch/mar based on the latter two damage mecha-
High Gloss Coatings
nisms.
D6279 Test Method for Rub Abrasion Mar Resistance of
High Gloss Coatings
1.4 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information G171 Test Method for Scratch Hardness of Materials Using
a Diamond Stylus
only.
1.5 This standard does not purport to address all of the
3. Summary of Test Method
safety problems, if any, associated with its use. It is the
3.1 This test method is based on representative samples of
responsibility of the user of this standard to establish appro-
the paint film being scratched using a nanoscratch instrument.
priate safety and health practices and determine the applica-
From information received during a scratch test, values for
bility of regulatory limitations prior to use.
plastic resistance and fracture resistance can be determined.
1 2
This test method is under the jurisdiction of ASTM Committee D01 on Paint For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Related Coatings, Materials, andApplications and is the direct responsibility of contact ASTM Customer Service at service@astm.org. For ASTM Book of ASTM
Subcommittee D01.23 on Physical Properties of Applied Paint Films. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2010. Published December 2010. Originally the ASTM website.
3
approved in 2005. Last previous edition approved in 2005 as D7187 – 05. DOI: The last approved version of this historical standard is referenced on
10.1520/D7187-10. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7187 − 10
3.2 From these values of plastic resistance and fracture instrumented scratch of controlled and variable normal force
resistance, the mechanistic aspects of scratch/mar behavior of and continuously measured displacement during testing. The
the coating can be subsequently compared. normal force must be feedback controlled, in order t
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:D7187–05 Designation:D7187–10
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 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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 PracticeforPreparationofCold-RolledSteelPanelsforTestingPaint,Varnish,ConversionCoatings,andRelatedCoating
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
Base
D1400 Test Method for Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to a
Nonferrous Metal Base
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 Test Method for Rub Abrasion Mar Resistance
of High Gloss Coatings
G171 Test Method for Scratch Hardness of Materials Using a Diamond Stylus
3. Summary of Test Method
3.1 This test method is based on representative samples of the paint film being scratched using a nanoscratch instrument. From
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 July 1, 2005. Published October 2005. DOI: 10.1520/D7187-05.
Current edition approved Dec. 1, 2010. Published December 2010. Originally approved in 2005. Last previous edition approved in 2005 as D7187 - 05. DOI:
10.1520/D7187-10.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForASTMBookofASTMStandards
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 ----------------------
D7187–10
information received during a scratch test, values for plastic resistance and fracture resistance can be determined.
3.2 From these values of plastic resistance
...
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