ASTM E1920-03(2008)

Standard Guide for Metallographic Preparation of Thermal Sprayed Coatings

SIGNIFICANCE AND USE
TSCs are used in a number of critical industrial components. TSCs can be expected to contain measurable levels of porosity and linear detachment. Accurate and consistent evaluation of specimens is essential to ensure the integrity of the coating and proper adherence to the substrate.
Example 1: By use of inappropriate metallographic methods, the apparent amount of porosity and linear detachment displayed by a given specimen can be increased, by excessive edge rounding, or decreased by smearing of material into voids. Therefore inaccurate levels of porosity and linear detachment will be reported even when the accuracy of the measurement technique is acceptable.
Example 2: Inconsistent metallographic preparation methods can cause the apparent amount of voids to vary excessively indicating a poorly controlled thermal spray process, while the use of consistent practice will regularly display the true microstructure and verify the consistency of the thermal spray process.
During the development of TSC procedures, metallographic information is necessary to validate the efficacy of a specific application.
Cross sections are usually taken perpendicular to the long axis of the specimen and prepared to reveal information concerning the following:
Variations in structure from surface to substrate,
The distribution of unmelted particles throughout the coating,
The distribution of linear detachment throughout the coating,
The distribution of porosity throughout the coating,
The presence of contamination within the coating,
The thickness of the coating (top coat and bond coat, where applicable),
The presence of interfacial contamination,
The integrity of the interface between the coating and substrate, and,
The integrity of the coating microstructure with respect to chemistry.
SCOPE
1.1 This guide covers recommendations for sectioning, cleaning, mounting, grinding, and polishing to reveal the microstructural features of thermal sprayed coatings (TSCs) and the substrates to which they are applied when examined microscopically. Because of the diversity of available equipment, the wide variety of coating and substrate combinations, and the sensitivity of these specimens to preparation technique, the existence of a series of recommended methods for metallographic preparation of thermal sprayed coating specimens is helpful. Adherence to this guide will provide practitioners with consistent and reproducible results. Additional information concerning standard practices for metallographic preparation can be found in Practice E 3.
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

• Status: Historical
• Publication Date: 30-Sep-2008
• ICS: 25.220.20 - Surface treatment
• Technical Committee: E04 - Metallography
• Drafting Committee: E04.01 - Specimen Preparation

Relations

• Replaces: ASTM E1920-03 - Standard Guide for Metallographic Preparation of Thermal Sprayed Coatings
• Effective Date: 01-Oct-2008
• Referred By: ASTM E2109-01(2021) - Standard Test Methods for Determining Area Percentage Porosity in Thermal Sprayed Coatings
• Effective Date: 01-Oct-2008
• Referred By: ASTM E3-11(2017) - Standard Guide for Preparation of Metallographic Specimens
• Effective Date: 01-Oct-2008

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: E1920 − 03(Reapproved 2008)
Standard Guide for
1
Metallographic Preparation of Thermal Sprayed Coatings
This standard is issued under the fixed designation E1920; 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 3.2.3 taper mount, n—ametallographicspecimencreatedby
mounting a feature, typically an interface or thin coating, at a
1.1 This guide covers recommendations for sectioning,
small angle to the polishing plane, such that the visible width
cleaning, mounting, grinding, and polishing to reveal the
exhibited by the feature is expanded.
microstructural features of thermal sprayed coatings (TSCs)
3.2.4 TSC, n—thermal sprayed coating, including, but not
and the substrates to which they are applied when examined
limited to, those formed by plasma, flame, and high velocity
microscopically. Because of the diversity of available
oxyfuel.
equipment, the wide variety of coating and substrate
combinations, and the sensitivity of these specimens to prepa-
4. Significance and Use
ration technique, the existence of a series of recommended
methods for metallographic preparation of thermal sprayed
4.1 TSCs are used in a number of critical industrial compo-
coating specimens is helpful. Adherence to this guide will
nents. TSCs can be expected to contain measurable levels of
provide practitioners with consistent and reproducible results.
porosity and linear detachment.Accurate and consistent evalu-
Additional information concerning standard practices for met-
ation of specimens is essential to ensure the integrity of the
allographic preparation can be found in Practice E3.
coating and proper adherence to the substrate.
1.2 This standard does not purport to address all of the 4.1.1 Example 1: By use of inappropriate metallographic
safety concerns, if any, associated with its use. It is the methods, the apparent amount of porosity and linear detach-
responsibility of the user of this standard to establish appro- ment displayed by a given specimen can be increased, by
priate safety and health practices and determine the applica- excessive edge rounding, or decreased by smearing of material
bility of regulatory limitations prior to use. into voids. Therefore inaccurate levels of porosity and linear
detachment will be reported even when the accuracy of the
2. Referenced Documents
measurement technique is acceptable.
2
4.1.2 Example 2: Inconsistent metallographic preparation
2.1 ASTM Standards:
methods can cause the apparent amount of voids to vary
E3 Guide for Preparation of Metallographic Specimens
excessively indicating a poorly controlled thermal spray
E7 Terminology Relating to Metallography
process, while the use of consistent practice will regularly
3. Terminology
display the true microstructure and verify the consistency of
the thermal spray process.
3.1 Definitions—For definitions of terms used in this guide,
see Terminology E7.
4.2 During the development of TSC procedures, metallo-
graphic information is necessary to validate the efficacy of a
3.2 Definitions of Terms Specific to This Standard:
specific application.
3.2.1 linear detachment, n—a region within a TSC in which
two successively deposited splats of coating material have not
4.3 Cross sections are usually taken perpendicular to the
metallurgically bonded.
long axis of the specimen and prepared to reveal information
concerning the following:
3.2.2 splat, n—an individual globule of thermal sprayed
4.3.1 Variations in structure from surface to substrate,
material that has been deposited on a substrate.
4.3.2 The distribution of unmelted particles throughout the
coating,
1
ThisguideisunderthejurisdictionofASTMCommitteeE04onMetallography
4.3.3 The distribution of linear detachment throughout the
and is the direct responsibility of Subcommittee E04.01 on Specimen Preparation.
coating,
Current edition approved Oct. 1, 2008. Published January 2009. Originally
4.3.4 The distribution of porosity throughout the coating,
approved in 1997. Last previous edition approved in 2003 as E1920–03. DOI:
10.1520/E1920-03R08.
4.3.5 The presence of contamination within the coating,
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.3.6 The thickness of the coating (top coat and bond coat,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
where applicable),
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 4.3.7 The presence of interfacial contamination,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United St
...

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:E1920–97 Designation:E1920–03 (Reapproved 2008)
Standard Guide for
1
Metallographic Preparation of Thermal Sprayed Coatings
This standard is issued under the fixed designation E 1920; 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 Thisguidecoversrecommendationsforsectioning,cleaning,mounting,grinding,andpolishingtorevealthemicrostructural
features of thermal sprayed coatings (TSCs) and the substrates to which they are applied when examined microscopically. Because
of the diversity of available equipment, the wide variety of coating and substrate combinations, and the sensitivity of these
specimens to preparation technique, the existence of a series of recommended methods for metallographic preparation of thermal
sprayed coating specimens is helpful. Adherence to this guide will provide practitioners with consistent and reproducible results.
Additional information concerning standard practices for metallographic preparation can be found in Practice E 3.
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:
E3 Practice of Preparation of Metallographic Specimens Guide for Preparation of Metallographic Specimens
E7 Terminology Relating to Metallography
3. Terminology
3.1 Definitions—For definitions of terms used in this guide, see Terminology E 7.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 linear detachment, n—a region within a TSC in which two successively deposited splats of coating material have not
metallurgically bonded.
3.2.2 splat, n—an individual globule of thermal sprayed material that has been deposited on a substrate.
3.2.3 taper mount, n—ametallographicspecimencreatedbymountingafeature,typicallyaninterfaceorthincoating,atasmall
angle to the polishing plane, such that the visible width exhibited by the feature is expanded.
3.2.4 TSC, n—thermal sprayed coating, including, but not limited to, those formed by plasma, flame, and high velocity oxyfuel.
4. Significance and Use
4.1 TSCs are used in a number of critical industrial components.TSCs can be expected to contain measurable levels of porosity
andlineardetachment.Accurateandconsistentevaluationofspecimensisessentialtoensuretheintegrityofthecoatingandproper
adherence to the substrate.
4.1.1 Example 1: By use of inappropriate metallographic methods, the apparent amount of porosity and linear detachment
displayed by a given specimen can be increased, by excessive edge rounding, or decreased by smearing of material into voids.
Therefore inaccurate levels of porosity and linear detachment will be reported even when the accuracy of the measurement
technique is acceptable.
4.1.2 Example 2: Inconsistent metallographic preparation methods can cause the apparent amount of voids to vary excessively
indicating a poorly controlled thermal spray process, while the use of consistent practice will regularly display the true
microstructure and verify the consistency of the thermal spray process.
4.2 During the development of TSC procedures, metallographic information is necessary to validate the efficacy of a specific
application.
4.3 Cross sections are usually taken perpendicular to the long axis of the specimen and prepared to reveal information
concerning the following:
1
This guide is under the jurisdiction of ASTM Committee E–4 on Metallography and is the direct responsibility of Subcommittee E04.01 on Sampling, Specimen
Preparation, and Photography.
Current edition approved Dec. 10, 1997. Published February 1998.
1
This guide is under the jurisdiction of ASTM Committee E04 on Metallography and is the direct responsibility of Subcommittee E04.01 on Specimen Preparation.
Current edition approved Oct. 1, 2008. Published January 2009. Originally approved in 1997. Last previous edition approved in 2003 as E 1920–03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E1920–03 (2008)
4.3.1 Variations in structure from surface to substrate,
4.3.2 The distrib
...

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:E1920–03 Designation:E1920–03 (Reapproved 2008)
Standard Guide for
1
Metallographic Preparation of Thermal Sprayed Coatings
This standard is issued under the fixed designation E 1920; 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 Thisguidecoversrecommendationsforsectioning,cleaning,mounting,grinding,andpolishingtorevealthemicrostructural
features of thermal sprayed coatings (TSCs) and the substrates to which they are applied when examined microscopically. Because
of the diversity of available equipment, the wide variety of coating and substrate combinations, and the sensitivity of these
specimens to preparation technique, the existence of a series of recommended methods for metallographic preparation of thermal
sprayed coating specimens is helpful. Adherence to this guide will provide practitioners with consistent and reproducible results.
Additional information concerning standard practices for metallographic preparation can be found in Practice E 3.
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:
E3 Guide for Preparation of Metallographic Specimens
E7 Terminology Relating to Metallography
3. Terminology
3.1 Definitions—For definitions of terms used in this guide, see Terminology E 7.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 linear detachment, n—a region within a TSC in which two successively deposited splats of coating material have not
metallurgically bonded.
3.2.2 splat, n—an individual globule of thermal sprayed material that has been deposited on a substrate.
3.2.3 taper mount, n—ametallographicspecimencreatedbymountingafeature,typicallyaninterfaceorthincoating,atasmall
angle to the polishing plane, such that the visible width exhibited by the feature is expanded.
3.2.4 TSC, n—thermal sprayed coating, including, but not limited to, those formed by plasma, flame, and high velocity oxyfuel.
4. Significance and Use
4.1 TSCs are used in a number of critical industrial components.TSCs can be expected to contain measurable levels of porosity
andlineardetachment.Accurateandconsistentevaluationofspecimensisessentialtoensuretheintegrityofthecoatingandproper
adherence to the substrate.
4.1.1 Example 1: By use of inappropriate metallographic methods, the apparent amount of porosity and linear detachment
displayed by a given specimen can be increased, by excessive edge rounding, or decreased by smearing of material into voids.
Therefore inaccurate levels of porosity and linear detachment will be reported even when the accuracy of the measurement
technique is acceptable.
4.1.2 Example 2: Inconsistent metallographic preparation methods can cause the apparent amount of voids to vary excessively
indicating a poorly controlled thermal spray process, while the use of consistent practice will regularly display the true
microstructure and verify the consistency of the thermal spray process.
4.2 During the development of TSC procedures, metallographic information is necessary to validate the efficacy of a specific
application.
4.3 Cross sections are usually taken perpendicular to the long axis of the specimen and prepared to reveal information
concerning the following:
1
This guide is under the jurisdiction of ASTM Committee E04 on Metallography and is the direct responsibility of Subcommittee E04.01 on Sampling, Specimen
Preparation, and Photography. Preparation.
Current edition approved May 10, 2003.Oct. 1, 2008. Published July 2003.January 2009. Originally approved in 1997. Last previous edition approved in 19972003 as E
1920–97. E 1920–03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E1920–03 (2008)
4.3.1 Variations in structure from surface to substrate,
4.3.2 The distribution of unmelted particles throughout the coating,
4.3.3 The distribution of linear detachment throughout the coating,
4.3.4 The distribution of porosity throughout the coating,
4.3.5 The presence of contamination within the
...