ASTM E2109-01
(Test Method)Test Methods for Determining Area Percentage Porosity in Thermal Sprayed Coatings
Test Methods for Determining Area Percentage Porosity in Thermal Sprayed Coatings
SCOPE
1.1 These test methods cover procedures to perform porosity ratings on metallographic specimens of thermal sprayed coatings (TSCs) prepared in accordance with Guide E1920 by direct comparison to standard images and via the use of automatic image analysis equipment.
1.2 These test methods deal only with recommended measuring methods and nothing in them should be construed as defining or establishing limits of acceptability for any measured value of porosity.
1.3 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.
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Designation: E 2109 – 01
Test Methods for
Determining Area Percentage Porosity in Thermal Sprayed
1
Coatings
This standard is issued under the fixed designation E 2109; 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.
1. Scope 3.2.2 linear detachment, n—a region within aTSC in which
two successively deposited splats of coating material have not
1.1 These test methods cover procedures to perform poros-
metallurgically bonded.
ity ratings on metallographic specimens of thermal sprayed
3.2.3 porosity, n—cavity type discontinuities (voids) or
coatings (TSCs) prepared in accordance with Guide E 1920 by
linear detachments within a sprayed coating.
direct comparison to standard images and via the use of
3.2.4 splat, n—an individual globule of thermal sprayed
automatic image analysis equipment.
material that has been deposited on a substrate.
1.2 These test methods deal only with recommended mea-
suring methods and nothing in them should be construed as
4. Significance and Use
defining or establishing limits of acceptability for any mea-
4.1 TSCs are susceptible to the formation of porosity due to
sured value of porosity.
a lack of fusion between sprayed particles or the expansion of
1.3 This standard does not purport to address all of the
gases generated during the spraying process. The determina-
safety concerns, if any, associated with its use. It is the
tion of area percent porosity is important in order to monitor
responsibility of the user of this standard to establish appro-
the effect of variable spray parameters and the suitability of a
priate safety and health practices and determine the applica-
coating for its intended purpose. Depending on application,
bility of regulatory limitations prior to use.
some or none of this porosity may be tolerable.
2. Referenced Documents 4.2 These test methods cover the determination of the area
percentage porosity of TSCs. Method A is a manual, direct
2.1 ASTM Standards:
2
comparison method utilizing the seven standard images in
E 3 Practice for Preparation of Metallographic Specimens
2
Figs. 1-7 which depict typical distributions of porosity in
E 7 Terminology Relating to Metallography
TSCs.MethodBisanautomatedtechniquerequiringtheuseof
E 562 Practice for Determining Volume Fraction by Sys-
2 a computerized image analyzer.
tematic Point Count
4.3 These methods quantify area percent porosity only on
E 1245 Practice for Determining the Inclusion Content or
the basis of light reflectivity from a metallographically pol-
Second-Phase Constituent Content of Metals byAutomatic
2
ished cross section. See Guide E 1920 for recommended
Image Analysis
metallographic preparation procedures.
E 1920 Guide for Metallographic Preparation of Thermal
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4.4 The person using these test methods must be familiar
Sprayed Coatings
with the visual features of TSCs and be able to determine
3. Terminology
differences between inherent porosity and oxides. The indi-
vidual must be aware of the possible types of artifacts that may
3.1 Definitions—For definitions of terms used in these test
be created during sectioning and specimen preparation, for
methods refer to Terminology E 7.
example, pullouts and smearing, so that results are reported
3.2 Definitions of Terms Specific to This Standard:
only on properly prepared specimens. Examples of properly
3.2.1 halo effect—unwanted detection of the perimeter of
preparedspecimensareshowninFigs.8-10.Iftherearedoubts
one phase (due to a shared gray value at the phase boundary)
as to the integrity of the specimen preparation it is suggested
when setting the detection limits of another.
that other means be used to confirm microstructural features.
This may include energy dispersive spectroscopy (EDS),
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This test method is under the jurisdiction of ASTM Committee E04 on
wavelength dispersive spectroscopy (WDS) or cryogenic frac-
Metallography and is the direct responsibility of Subcommittee E04.14 on Quanti-
ture of the coating followed by analysis of the fractured
tative Metallography.
surfaces with a scanning electron microscope (SEM).
Current edition approved Dec. 10, 2001. Published January 2002. Originally
published as E 2109 – 00. Last previous edition E 2109 – 00.
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Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E 2109
FIG. 1 — 0.5 % Porosity
FIG. 2 — 1.0 % Porosity
5. Apparatus 5.2 Test Method B—TestMethodBrequiresareflectedlight
metallurgical microscope, upright or inverted, equipped
...
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