ISO 23114:2020

Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for determining bonding strength of ceramic coatings

This document specifies the testing method for the determination of the bonding strength of ceramic coatings at ambient temperature by the compression tests on the cross-joined test pieces. Methods for test piece preparation, test mode and rate, data collection and reporting procedures are addressed. This document applies primarily to any ceramic coatings, thick or thin, bonded onto substrates of various materials. The test method described can be used for materials research, quality control, characterization and design data generation purposes.

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General Information

• Status: Published
• Publication Date: 05-Jan-2020
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206/WG 10 - Coatings
• Current Stage: 9093 - International Standard confirmed
• Start Date: 11-Dec-2025
• Completion Date: 13-Dec-2025

Overview

ISO 23114:2020 specifies a standardized laboratory method to determine the bonding strength of ceramic coatings (fine/advanced ceramics) at ambient temperature. The method uses compression tests on a specially prepared cross-joined test piece to produce either tensile or shear stresses at the coating–substrate interface. It applies to thin or thick ceramic coatings bonded to a variety of substrates and is intended for materials research, quality control, characterization and design-data generation.

Key topics and technical requirements

• Test principle: compressive loading of a cross-joined specimen to induce tensile or shear stresses at the interface; record failure load and calculate bonding strength from the joined area.
• Test pieces: preparation of a coating sample and a perpendicular coupling bar joined by high-strength adhesive to create the cross-joined test piece; storage and number of test pieces are specified.
• Fracture modes: interface debonding (true bonding strength), cohesive failure within the coating, and adhesive joint failure - single or mixed modes are possible and influence interpretation of results.
• Apparatus and metrology:
  • Testing machine accuracy: in accordance with ISO 7500-1, Class 1 (1% load accuracy).
  • Data acquisition: recording load vs. displacement/time; devices accurate to 1% with a minimum acquisition rate of 10 Hz (50 Hz recommended).
  • Dimension measurement: micrometers or equivalent with resolution/accuracy of 0.01 mm (per ISO 3611).
  • Fixtures: pressure head and sample holder geometry to avoid asymmetric stress; fixture material with elastic modulus > 200 GPa recommended.
• Test procedure and calculation: defined placement, cross-head rate, measurement of tensile/shear failure loads, evaluation of true debonded area, and calculation of tensile bonding strength and shear bonding strength.
• Reporting: procedures for data collection and reporting of failure loads, joined area, fracture mode and calculated strengths.

Practical applications

• Quality control and production acceptance testing of ceramic coatings (protective, thermal barrier, wear-resistant coatings).
• Research and development: compare coating processes, materials, surface treatments and adhesives.
• Materials characterization and design: provide input data for component design, simulation and lifetime assessments.
• Failure analysis: determine whether coating detachment is due to poor interface bonding, cohesive weakness, or adhesive joint failure.

Who should use this standard

• Materials scientists and R&D engineers working with advanced ceramic coatings
• Coating process engineers and QC laboratories
• Component designers and reliability engineers requiring bond-strength data
• Test laboratories performing interlaboratory comparisons and method validation

Related standards

• ISO 7500-1 - Calibration and verification of static uniaxial testing machines
• ISO 3611 - Micrometers for external measurements (dimensional metrology)
• Annex A of ISO 23114:2020 addresses interlaboratory testing guidance

Keywords: ISO 23114:2020, bonding strength, ceramic coatings, fine ceramics, tensile bonding strength, shear bonding strength, cross-joined test piece, test method, quality control, materials research.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 23114
First edition
2020-01
Fine ceramics (advanced ceramics,
advanced technical ceramics) — Test
method for determining bonding
strength of ceramic coatings
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 3
5 Principle . 3
6 Apparatus . 5
6.1 Testing machine . 5
6.2 Data acquisition . 5
6.3 Dimension-measuring device. 6
6.4 Testing fixture . 6
7 Test pieces . 7
7.1 Test piece preparation . 7
7.1.1 Coating sample . 7
7.1.2 Coupling bar . . 7
7.1.3 Joining of coating sample with coupling bar . 7
7.2 Test piece storage . 8
7.3 Number of test pieces . 8
8 Test procedure . 8
8.1 Placement of testing pieces . 8
8.2 Test mode and rate . 8
8.3 Measurements of the tensile bonding strength . 8
8.4 Measurements of the shear bonding strength . 9
8.5 E valuation of the true coating debonded area . 9
8.6 Post test . 9
9 Calculation of results .10
9.1 Tensile bonding strength of ceramics coating .10
9.2 Shear bonding strength of ceramics coating .10
10 Analysis of precision and uncertainty .10
11 Test report .10
Annex A (informative) Interlaboratory testing .12
Bibliography .13
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
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expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 23114:2020(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Test method for determining bonding
strength of ceramic coatings
1 Scope
This document specifies the testing method for the determination of the bonding strength of ceramic
coatings at ambient temperature by the compression tests on the cross-joined test pieces. Methods for
test piece preparation, test mode and rate, data collection and reporting procedures are addressed.
This document applies primarily to any ceramic coatings, thick or thin, bonded onto substrates of
various materials. The test method described can be used for materials research, quality control,
characterization and design data generation purposes.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3611, Geometrical product specifications (GPS) — Dimensional measuring equipment: Micrometers for
external measurements — Design and metrological characteristics
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
ceramic coating
coating of ceramics onto a substrate, via a physical or chemical technique, which creates an interface or
boundary between the coating and the substrate
3.2
interface
smooth or rough boundary generated between coating and substrate that results from one or several
bonding mechanisms, for example mechanical anchorage, interatomic or intermolecular bonds
3.3
cross-joined test piece
test piece prepared by joining coating sample (see Figure 1 and 7.1.1) and coupling bar (see Figure 2
and 7.2.2) perpendicularly to each other at middle, by means of high-strength adhesive, as shown in
Figure 3
Key
1 notch
2 coating
3 substrate
Figure 1 — Schematic of the coating sample
a)
b)
Key
1 groove
2 sloped end
Figure 2 — Schematic of the coupling bar
Figure 3 — Schematic of the cross-joined test piece
2 © ISO 2020 – All rights reserved

3.4
tensile failure load
maximum load applied to the horizontally placed cross-joined test piece during a test by subjecting load
normal to interface between coating and substrate
3.5
tensile bonding strength
tensile stress calculated from the tensile failure load and the cross-joined area
3.6
shear failure load
maximum load applied to the vertically placed cross-joined test piece during a test by subjecting load
parallel to interface between coating and substrate
3.7
shear bonding strength
shear stress calculated by using the shear failure load and the cross-joined area
4 Symbols
Symbol Designation Unit References
2 2
A Cross-joined area (=b ) mm Formulae (1) and (2)
A True coating debonded area mm 8.5
c
b Test piece width mm Table 1
b Groove width of sample holder mm Figure 6 b)
b Sample holder width mm Figure 6 b)
b Pressure head width (=b) mm Figure 6 a)
c Pressure head length ( 1 2
c Slot span of pressure head (>b) mm Figure 6 a)
d Space of two notches (=b) mm Table 1
h Test piece thickness mm Table 1
h Sample holder height mm Figure 6 b)
h Pressure head height mm Figure 6 a)
h Slot depth of pressure head (>b) mm Figure 6 a)
l Test piece length mm Table 1
l Sample holder length mm Figure 6 b)
l Groove length of sample holder (>c ) mm Figure 6 a)
2 1
P Failure load to debonding N Formulae (1) and (2)
c
σ Tensile bonding strength by calculation MPa Formula (1)
t
σ Tensile bonding strength of ceramics coating MPa 9.1
ct
τ Shear bonding strength by calculation MPa Formula (2)
τ Shear bonding strength of ceramics coating MPa 9.2
c
5 Principle
A cross-joined test piece is subjected to an increasing compression load giving a tensile or shear stress
on the area that is joined until the coating is debonded. Two different forms of mounting the cross-joined
test piece in a fixture are conducted to measure the tensile and shear bond strength, respectively. In the
case of the tensile test, a uniaxial tensile stress is generated when the cross-joined test piece is subjected
to compressive load, as shown in Figure 4. The tensile strength of the coating–substrate interface, or
the cohesive strength of the ceramic coating, will be obtained. In the case of the shear strength test, a
cross-joined test piece is loaded in compression to induce failure by shear at the interface, as shown in
ISO
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