ASTM C1624-05

Standard Test Method for Adhesion Strength and Mechanical Failure Modes of Ceramic Coatings by Quantitative Single Point Scratch Testing

SCOPE
1.1 This test method covers the determination of the practical adhesion strength and mechanical failure modes of hard (Vickers Hardness HV = 5 GPa or higher), thin (≤30 μm) ceramic coatings on metal and ceramic substrates at ambient temperatures. These ceramic coatings are commonly used for wear/abrasion resistance, oxidation protection, and functional (optical, magnetic, electronic, biological) performance improvement.
1.2 In the test method, a diamond stylus of defined geometry (Rockwell C, a conical diamond indenter with an included angle of 120° and a spherical tip radius of 200 μm) is drawn across the flat surface of a coated test specimen at a constant speed and a defined normal force (constant or progressively increasing) for a defined distance. The damage along the scratch track is microscopically assessed as a function of the applied force. Specific levels of progressive damage are associated with increasing normal stylus forces. The force level(s) which produce a specific type/level of damage in the coating are defined as a critical scratch load(s). The test method also describes the use of tangential force and acoustic emission signals as secondary test data to identify different coating damage levels.
1.3 Applicability to Coatings—This test method is applicable to a wide range of hard ceramic coating compositions: carbides, nitrides, oxides, diamond, and diamond-like carbon on ceramic and metal substrates. The test method, as defined with the 200 μm radius diamond stylus, is commonly used for coating thicknesses in the range of 0.1 to 30 μm. Test specimens generally have a planar surface for testing, but cylinder geometries can also be tested with an appropriate fixture.
1.4 Principal Limitations:
1.4.1 The test method does not measure the fundamental adhesion strength of the bond between the coating and the substrate. Rather, the test method gives an engineering measurement of the practical (extrinsic) adhesion strength of a coating-substrate system, which depends on the complex interaction of the test parameters (stylus properties and geometry, loading rate, displacement rate, and so forth) and the coating/substrate properties (hardness, fracture strength, modulus of elasticity, damage mechanisms, microstructure, flaw population, surface roughness, and so forth).
1.4.2 The defined test method is not directly applicable to metal or polymeric coatings which fail in a ductile, plastic manner, because plastic deformation mechanisms are very different than the brittle damage modes and features observed in hard ceramic coatings. The test method may be applicable to hard metal coatings which fail in a brittle mode with appropriate changes in test parameters and damage analysis procedures and criteria.
1.4.3 The test method, as defined with the Rockwell C diamond stylus and specific normal force and rate parameters, is not recommended for very thin (30 μm). Such coatings may require different stylus geometries, loading rates, and ranges of applied normal force for usable, accurate, repeatable results.
1.4.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Test data values in SI units (newtons (N) for force and millimetres (mm) for displacement) are to be considered as standard and are in accordance with IEEE/ASTM SI 10.
1.4.5 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

• Status: Historical
• Publication Date: 31-May-2005
• ICS: 25.220.99 - Other treatments and coatings
• Technical Committee: C28 - Advanced Ceramics
• Drafting Committee: C28.04 - Applications

Relations

• Replaced By: ASTM C1624-05(2010) - Standard Test Method for Adhesion Strength and Mechanical Failure Modes of Ceramic Coatings by Quantitative Single Point Scratch Testing
• Effective Date: 01-Dec-2010

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1624 – 05
Standard Test Method for
Adhesion Strength and Mechanical Failure Modes of
Ceramic Coatings by Quantitative Single Point Scratch
Testing
This standard is issued under the fixed designation C1624; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope surement of the practical (extrinsic) adhesion strength of a
coating-substrate system, which depends on the complex
1.1 This test method covers the determination of the prac-
interaction of the test parameters (stylus properties and geom-
tical adhesion strength and mechanical failure modes of hard
etry, loading rate, displacement rate, and so forth) and the
(Vickers Hardness HV = 5 GPa or higher), thin (#30 µm)
coating/substrateproperties(hardness,fracturestrength,modu-
ceramic coatings on metal and ceramic substrates at ambient
lus of elasticity, damage mechanisms, microstructure, flaw
temperatures. These ceramic coatings are commonly used for
population, surface roughness, and so forth).
wear/abrasion resistance, oxidation protection, and functional
1.4.2 The defined test method is not directly applicable to
(optical, magnetic, electronic, biological) performance im-
metal or polymeric coatings which fail in a ductile, plastic
provement.
manner, because plastic deformation mechanisms are very
1.2 Inthetestmethod,adiamondstylusofdefinedgeometry
different than the brittle damage modes and features observed
(Rockwell C, a conical diamond indenter with an included
inhardceramiccoatings.Thetestmethodmaybeapplicableto
angle of 120° and a spherical tip radius of 200 µm) is drawn
hard metal coatings which fail in a brittle mode with appro-
across the flat surface of a coated test specimen at a constant
priate changes in test parameters and damage analysis proce-
speed and a defined normal force (constant or progressively
dures and criteria.
increasing) for a defined distance. The damage along the
1.4.3 The test method, as defined with the Rockwell C
scratch track is microscopically assessed as a function of the
diamond stylus and specific normal force and rate parameters,
applied force. Specific levels of progressive damage are
isnotrecommendedforverythin(<0.1µm)orthickercoatings
associated with increasing normal stylus forces. The force
(>30 µm). Such coatings may require different stylus geom-
level(s) which produce a specific type/level of damage in the
etries, loading rates, and ranges of applied normal force for
coatingaredefinedasacriticalscratchload(s).Thetestmethod
usable, accurate, repeatable results.
alsodescribestheuseoftangentialforceandacousticemission
1.4.4 The values stated in SI units are to be regarded as
signals as secondary test data to identify different coating
standard. No other units of measurement are included in this
damage levels.
standard. Test data values in SI units (newtons (N) for force
1.3 Applicability to Coatings—This test method is appli-
andmillimetres(mm)fordisplacement)aretobeconsideredas
cable to a wide range of hard ceramic coating compositions:
standard and are in accordance with IEEE/ASTM SI10.
carbides, nitrides, oxides, diamond, and diamond-like carbon
1.4.5 This standard does not purport to address all of the
on ceramic and metal substrates. The test method, as defined
safety concerns, if any, associated with its use. It is the
with the 200 µm radius diamond stylus, is commonly used for
responsibility of the user of this standard to establish appro-
coating thicknesses in the range of 0.1 to 30 µm. Test
priate safety and health practices and determine the applica-
specimens generally have a planar surface for testing, but
bility of regulatory limitations prior to use.
cylinder geometries can also be tested with an appropriate
1.5 Organization—The test method is organized into the
fixture.
following sections:
1.4 Principal Limitations:
Section
1.4.1 The test method does not measure the fundamental
Scope 1
adhesion strength of the bond between the coating and the
Purpose and Description 1.1
substrate. Rather, the test method gives an engineering mea-
Applicability 1.3
Principal Limitations 1.4
Organization 1.5
Referenced Documents 2
This test method is under the jurisdiction of ASTM Committee C28 on
ASTM Standards 2.1
Advanced Ceramics and is the direct responsibility of Subcommittee C28.04 on
Other Standards and References 2.2
Applications.
Current edition approved June 1, 2005. Published June 2005. DOI: 10.1520/
C1624-05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1624 – 05
E18 Test Methods for Rockwell Hardness of Metallic Ma-
Section
Terminology 3
terials
Summary of Test Method 4
E750 Practice for CharacterizingAcoustic Emission Instru-
Significance and Use 5
mentation
Test Methodology and Experimental Control 6
Test Overview 6.1
E1316 Terminology for Nondestructive Examinations
Test Modes 6.2
E1932 Guide for Acoustic Emission Examination of Small
Primary and Supplementary Measurements 6.3
Parts
Critical Scratch Load Damage Criteria and Scratch Atlas 6.4
Experimental Factors and Variables 6.5
IEEE/ASTM SI10 Standard for Use of the International
Interferences 7
System of Units (SI) (The Modern Metric System)
Material and Specimen Related 7.2
Test Method Related 7.3 2.2 ASME Standard:
Apparatus 8
ASME B46.1 Surface Texture (Surface Roughness, Wavi-
General Description 8.1
ness, and Lay)
Stylus and Stylus Mounting 8.2
Mechanical Stage and Displacement Control 8.3 2.3 CEN Standard:
Test Frame and Force Application System 8.4
CEN prEN 1071-3 Advanced Technical Ceramics—
Force and Displacement Sensors 8.5
Methods of Test for Ceramic Coatings—Part 3: Determi-
Optical Analysis and Measurement 8.6
nation OfAdhesiveAnd Other Mechanical Failure Modes
Data Acquisition and Recording 8.7
Acoustic Emission (Optional) 8.8
By A Scratch Test
Coating Adhesion Reference Specimens (Optional) 8.9
Coating Surface Profilometry (Optional) 8.10
3. Terminology
Data Analysis and Output Software (Optional) 8.11
Test Specimens 9
3.1 Definitions:
Specimen Requirements 9.1
3.1.1 acoustic emission, n—class of phenomenon in which
Specimen Characterization 9.2
Specimen Size 9.3 elasticwavesaregeneratedbytherapidreleaseofenergyfrom
Specimen Flatness and Level 9.4
localized sources within a material, or the transient waves so
Polishing (Optional) 9.5
generated. E1316
Specimen Exposure Conditioning (Optional) 9.6
Specimen Cleaning 9.7
3.1.2 adhesive failure, n—detachment and separation of a
Specimen Handling and Storage 9.8
coating from the substrate with cracking and debonding at the
Calibration 10
coating-substrate interface.
System Calibration 10.1
Reference Specimens 10.2 3.1.3 cohesive failure, n—material damage and cracking in
Test Procedure 11
the coating or in the substrate, separate and distinct from
Calibration 11.1
detachment and adhesive debonding at the coating-substrate
Test Mode Selection 11.2
Test Planning 11.3
interface.
Stylus Inspection and Cleaning 11.4
3.1.4 critical scratch load (L ), n—appliednormalforceat
CN
Environmental Conditions 11.5
which a specific, well-defined, recognizable damage/failure
System Set-Up and Check 11.6
Test Specimen Mounting 11.7
event occurs or is observed in the scratch test of a specific
Conducting the Test 11.8
coating on a specific substrate.
Specimen Count 11.9
3.1.4.1 Discussion—The subscript N is used to identify
Invalid and Censored Data 11.10
Scratch Damage Assessment 11.11
progressive failure events. For example, L is often used to
C1
Calculations 12
identify the first level of cohesive failure in the coating itself;
Report 13
L is often used to identify first adhesive failure between the
Test Identification 13.2
C2
Specimen Information 13.3
coating and the substrate. Multiple subscripts can be used for
Test Equipment and Procedure Information 13.4
progressive levels of distinct damage in a specific coating-
Test Data and Statistics 13.5
substrate systems.
Precision and Bias 14
Keywords 15
3.1.5 fundamental adhesion, n—summation of all interfa-
Rockwell Diamond Indenter Specifications Annex A1
cial intermolecular interactions between a film or coating and
Alignment and Calibration Annex A2
its substrate.
Repeatability and Reproducibility Studies Annex A3
Coating Damage Criteria and Scratch Atlas Appendix X1
3.1.6 normal force (L ), n—in a scratch test, the force
N
Experimental Variables in Scratch Adhesion Testing Appendix X2
exerted by the stylus, perpendicular to the test surface of the
Bibliography
test specimen.
3.1.7 practical adhesion, n—force or work required to
2. Referenced Documents
2 remove or detach a film or coating from its substrate irrespec-
2.1 ASTM Standards:
tive of the locus of failure.
B659 Guide for Measuring Thickness of Metallic and Inor-
3.1.7.1 Discussion—“Practical adhesion” is a test concept
ganic Coatings
which uses various engineering coating adhesion test methods
E4 Practices for Force Verification of Testing Machines
Available from American Society of Mechanical Engineers (ASME), ASME
For referenced ASTM standards, visit the ASTM website, www.astm.org, or International Headquarters, Three ParkAve., NewYork, NY10016-5990, www.as-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM me.org.
Standards volume information, refer to the standard’s Document Summary page on Available from European Committee for Standardization (CEN), 36 rue de
the ASTM website. Stassart, B–1050 Brussels, www.cenorm.be.
C1624 – 05
to obtain a quantitative, reproducible adhesion measurement
which can be related to the functional performance of the
coating. The practical adhesion is an extrinsic property which
depends on the complex interaction of coating/substrate prop-
erties and characteristics with the specific test parameters.
3.1.8 stylus drag coeffıcient, n—in scratch testing, the di-
mensionless ratio of the tangential force to the normal force
applied to the stylus at a specific point in the scratch test.
3.1.8.1 Discussion—The term stylus drag coefficient is
preferred to the more common term scratch coefficient of
friction (SCF). The tangential force is primarily a measure of
the perpendicular force required to plow the indenter through
the coating, rather than to slide it on the surface (sliding
friction is a relatively minor contribution to the measured
tangential force unless penetration is very small and surface
FIG. 2 Schematic Example of Progressive Damage in Scratch
properties dominate). Thus the term friction coefficient is not Track in a Progressive Load Scratch Test
appropriate for these stylus scratch tests. The SCF term is too
easily misunderstood or misused as a measurement of sliding
specific, defined, reproducible type/level of damage is defined
friction.
as a critical scratch load (L ). For a given coating-substrate
C
3.1.9 tangential force (L ), n—force that opposes the rela-
T system, one or more different critical scratch loads (L ) can
CN
tive motion between a moving stylus and the surface that is
be defined for progressive levels of defined coating damage.
beingscratchedbythestylusandwhichisperpendiculartothe
4.3 Coating damage is assessed by optical microscopy or
normal force exerted by the stylus (also called the friction
scanning electron microscopy, or both, during or after the
force, drag force, or the scratching force).
scratchtestisdone.Thetangentialforceandacousticemission
signals can also be measured and recorded during the scratch
4. Summary of Test Method
test process and used as supplementary test data to identify
4.1 This test consists of producing and assessing controlled
different coating damage levels. In commercial instruments,
damageinahardceramiccoatingbysinglepointscratchaction
computerized electronic systems are commonly used to apply,
(seeFig.1).Thescratchisdevelopedonacoatedtestspecimen
control, measure, and record the force signals and acoustic
by drawing a diamond stylus of defined geometry and tip size
emissionsignalsandtocontrolthestylus-specimenmovement.
(Rockwell C, 200 µm radius) across the flat surface of the
4.4 The two primary modes of scratch adhesion testing are
specimen at a constant speed and a controlled and measured
constant load and progressive load. In constant load (CL)
normal force (constant or progressively increasing). With
scratch testing, the normal force on the stylus is maintained at
increasing applied normal force, the stylus produces progres-
a constant level as the stylus moves in relation to the test
sive mechanical damage in the coating and the substrate
specimen surface. Sequential scratch tests are done at increas-
through the complex combination of elastic/plastic indentation
ing force increments to determine the critical scratch load for
stresses, frictional forces, and residual internal stresses in the
a given damage level.
coating/substrate system (Fig. 2).
NOTE 1—Test systems may have either a movable stage or a movable
4.2 The specific levels and types of progressive damage in
stylus with the alternate component in a fixed position.
the scratch track are assessed and associated with the applied
4.5 In progressive load (PL) scratch tests, the applied stylus
normal stylus forces. The normal force which produces a
force is linearly increased to a defined maximum force as the
stylus moves in relation to the test specimen surface.
4.6 The critical scratch loads at which a defined coating
failure event occurs depend on a complex interaction of
coating-substrate properties and test parameters/conditions. It
is the purpose of this test standard to: (1) describe and define
the test equipment and procedures and the major and minor
coating-substrate properties which have to be controlled, mea-
sured, and understood to produce reliable, comparable coating
adhesion test data, and (2) define a report format that will
provide complete and accurate test data.
5. Significance and Use
5.1 This test is intended to assess the mechanical integrity,
failure modes, and practical adhesion strength of a specific
hard ceramic coating on a given metal or ceramic substrate.
The test method does not measure the fundamental “adhesion
FIG. 1 Test Method Schematic strength” of the bond between the coating and the substrate.
C1624 – 05
Rather, the test method gives a quantitative engineering mea- 5.8 The test is commonly conducted under unlubricated
surement of the practical (extrinsic) adhesion strength and conditionsandatroomtemperature.However,itisfeasibleand
possib
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