SIST EN ISO 26424:2016

SLOVENSKI STANDARD
01-junij-2016
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SIST EN 1071-6:2009
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Fine ceramics (advanced ceramics, advanced technical ceramics) - Determination of the
abrasion resistance of coatings by a micro-scale abrasion test (ISO 26424:2008)
Hochleistungskeramik - Bestimmung der Beständigkeit gegen Abrieb von Schichten
durch eine Mikroabriebprüfung (ISO 26424:2008)
Céramiques techniques - Détermination de la résistance à l'abrasion des revêtements
par essai d'abrasion à micro-échelle (ISO 26424:2008)
Ta slovenski standard je istoveten z: EN ISO 26424:2016
ICS:
25.220.99 Druge obdelave in prevleke Other treatments and
coatings
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 26424
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2016
EUROPÄISCHE NORM
ICS 81.060.30 Supersedes EN 1071-6:2007
English Version
Fine ceramics (advanced ceramics, advanced technical
ceramics) - Determination of the abrasion resistance of
coatings by a micro-scale abrasion test (ISO 26424:2008)
Céramiques techniques - Détermination de la Hochleistungskeramik - Bestimmung der Beständigkeit
résistance à l'abrasion des revêtements par essai gegen Abrieb von Schichten durch eine
d'abrasion à micro-échelle (ISO 26424:2008) Mikroabriebprüfung (ISO 26424:2008)
This European Standard was approved by CEN on 18 March 2016.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 26424:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
The text of ISO 26424:2008 has been prepared by Technical Committee ISO/TC 206 “Fine ceramics” of
the International Organization for Standardization (ISO) and has been taken over as EN ISO 26424:2016
by Technical Committee CEN/TC 184 “Advanced technical ceramics” the secretariat of which is held by
DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2016, and conflicting national standards shall
be withdrawn at the latest by October 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN 1071-6:2007.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 26424:2008 has been approved by CEN as EN ISO 26424:2016 without any modification.

INTERNATIONAL ISO
STANDARD 26424
First edition
2008-11-01
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Determination of the abrasion resistance
of coatings by a micro-scale abrasion
test
Céramiques techniques — Détermination de la résistance à l'abrasion
des revêtements par essai d'abrasion à micro-échelle

Reference number
ISO 26424:2008(E)
©
ISO 2008
ISO 26424:2008(E)
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ii © ISO 2008 – All rights reserved

ISO 26424:2008(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Significance and use . 1
5 Principle. 2
6 Apparatus and materials. 2
6.1 Test system . 2
6.2 Test balls . 2
6.3 Abrasive slurry. 3
6.4 Measurement of crater dimensions . 4
7 Preparation of test pieces. 5
8 Test procedure . 5
8.1 Different types of test. 5
8.1.1 Type A: no perforation of coating. 5
8.1.2 Type B: perforation of coating . 5
8.2 Type A test: no perforation of coating. 5
8.3 Type B test: perforation of coating. 7
9 Analysis of results. 8
9.1 Type A test: no perforation of coating. 8
9.1.1 Basic equations . 8
9.1.2 Calculation of K . 9
c
9.2 Type B test: perforation of coating. 9
9.2.1 Basic equations . 9
9.2.2 Calculation of K and K . 10
c s
10 Test reproducibility, repeatability and limits . 10
10.1 Reproducibility and repeatability. 10
10.2 Limits. 11
11 Test report . 13
Annex A (informative) Measurement of coating thickness . 14
Bibliography . 15

ISO 26424:2008(E)
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 committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 26424 was prepared by Technical Committee ISO/TC 206, Fine ceramics.

iv © ISO 2008 – All rights reserved

INTERNATIONAL STANDARD ISO 26424:2008(E)

Fine ceramics (advanced ceramics, advanced technical
ceramics) — Determination of the abrasion resistance of
coatings by a micro-scale abrasion test
1 Scope
This International Standard specifies a method for measuring the abrasive wear rate of ceramic coatings by
means of a micro-scale abrasion wear test based on the well-known crater-grinding technique used for
[11]
coating thickness determination in ISO 26423 .
The method can provide data on both coating and substrate wear rates, either by performing two separate
tests or by careful analysis of the data from a single test series.
The method can be applied to samples with planar or non-planar surfaces, but the results analysis described
in Clause 9 applies only to flat samples. For non-planar samples, a more complicated analysis, possibly
requiring the use of numerical methods, is required.
2 Normative references
The following referenced documents are indispensable for the application 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 3290-1, Rolling bearings — Balls — Part 1: Steel balls
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
abrasive wear rate
abrasive wear coefficient
K
volume of material removed in unit sliding distance under a normal contact load of 1 N
4 Significance and use
Although few protective coatings are subject to single wear processes, the abrasive wear resistance of such
coatings can play a decisive role in their performance. Hence, knowledge of the abrasive wear resistance of
ceramic coatings can help in the proper selection of coatings for applications where abrasion plays a major
role in their degradation. Although techniques exist to measure the abrasive wear behaviour of bulk materials
and thick films (see References [1] to [3]), these techniques are not easily applied to thin films and the results
are difficult to interpret when the methods are used on curved surfaces.
ISO 26424:2008(E)
The purpose of this International Standard is to provide a method for measuring the abrasion resistance of
both thin and thick coatings and of bulk materials. The test can be carried out on flat surfaces or surfaces with
a known radius of curvature and requires test pieces measuring only a few square millimetres. However, the
calculations described in Clause 9 apply only to flat test pieces and are applicable only to homogeneous
single-layer coatings. Errors may occur if the test is used on inhomogeneous coatings. References [4] and [5]
give details of analytical treatments for determining the wear rate of coatings on curved surfaces.
By proper treatment of the results as indicated in 9.2, where the test produces penetration of the coating, it
can provide abrasive wear coefficients for both the coating and the substrate from a single test series.
Although the test is designed to allow quantitative measurement of abrasive wear coefficients, it can be
adapted as a quality control test for use on real components.
5 Principle
In the test, a ball is rotated whilst being pressed against the test piece, and an abrasive slurry is fed into the
contact zone. A spherical depression is produced, and the size of this depression is measured. Where
perforation of the coating does not occur, the wear rate of the coating can be obtained from a single crater.
When perforation of the coating occurs, the wear rate of both the coating and the substrate can be calculated
by making a series of such craters and measuring their dimensions.
6 Apparatus and materials
6.1 Test system
A ball which can be rotated and pressed against the coated test piece shall be used. Two variants of the ball
system are shown in Figure 1, where either the test piece, mounted on a deadweight-loaded lever, is pressed
against a directly driven ball or the ball’s own weight presses it against the test piece.
[6]
NOTE It has been found that the results obtained with free-ball systems [see Figure 1 a)] can vary depending on
the precise system geometry. In particular, it has been found that the tilt angle of the test piece holder and the width of the
groove in the drive shaft that supports the ball can have an important influence on the results. A tilt angle of 60° to 75° and
a shaft groove width of 10 mm have been found to result in the smallest variability under typical conditions.
The test system shall be constructed so that the rotational speed of the ball remains constant throughout any
test and is reproducible to better than ± 10 % of the nominal value between tests. The drive shaft shall have a
total run-out of less than 20 µm at the points of contact with the ball.
6.2 Test balls
The balls used are typically 25-mm-diameter hardened steel, e.g. UNS G52986 (SAE 52100) and shall, prior
to any conditioning, conform to the requirements of ISO 3290-1.
[7]
NOTE 1 Balls can be used in a polished condition, but it has been found that the test behaviour is erratic and poor
results are obtained if balls are used without conditioning.
The recommended conditioning treatment consists of running the new test ball for at least 300 revolutions on
a non-critical part of the test piece, or another suitable surface, under normal test conditions and repeating this
for at least five different orientations of the ball before starting the test programme.
NOTE 2 A flat, ground steel coupon with a hardness of between 200 HV30 and 800 HV30 has been found to be
suitable for conditioning the ball.
NOTE 3 Following conditioning, balls have been found to be usable for around 50 individual craters, depending on the
precise conditions used.
2 © ISO 2008 – All rights reserved

ISO 26424:2008(E)
Balls shall be subjected to regular performance checks to ensure that they continue to produce acceptable
craters. Balls shall be replaced if such a check indicates any abnormal cratering behaviour.
NOTE 4 Performance checks can be carried out using any suitable test piece, such as hardened and tempered high-
speed steel, or a well-characterized titanium nitride or other coating deposited on a stable substrate material.

a)  Free-ball system
b)  Fixed-ball system
Key
1 ball 5 load cell
2 test piece 6 weight
3 drive shaft 7 pivot point
4 test piece support 8 lever
Figure 1 — Two different types of ball cratering system
6.3 Abrasive slurry
In all cases, a slurry of silicon carbide (SiC) or another suitable abrasive in a suitable liquid, normally water,
shall be used.
The abrasive is normally F1200 SiC, but F1200 alumina or another fine abrasive can be used. The average
size of the abrasive should preferably not exceed 5 µm.
ISO 26424:2008(E)
The use of different abrasive media will produce different wear rates, and results shall not be compared
unless they are obtained from craters produced under identical conditions.
The slurry used shall be kept homogeneous throughout the test. This can be done by stirring the slurry
continuously or by adding stabilizers.
If testing is to be undertaken on coatings deposited onto steel substrates that are susceptible to corrosion, it is
recommended that sodium nitrite (NaNO ) be added to the slurry at the rate of 1 g for each 100 cm of water
to prevent corrosion of craters before they can be measured.
The abrasive slurry shall be made from the abrasive powder and the chosen liquid in the required proportions.
As the mode of wear that is observed can depend critically on the concentration of the abrasive slurry, two
concentrations are recommended. These are:
a) Dilute (promotes grooving wear)
Concentration 2 % by volume.
−3 3
For SiC, for example, with a density of 3,2 g⋅cm , this is achieved by mixing 6,4 g of SiC into 98 cm of
distilled or deionized water.
b) Concentrated (promotes rolling wear)
Concentration 20 % by volume.
−3 3
For SiC, for example, with a density of 3,2 g⋅cm , this is achieved by mixing 80 g of SiC into 100 cm of
distilled or deionized water.
NOTE The type of wear promoted depends both on the concentration of the slurry and on the type of abrasive, as
well as on the material being tested. For example, it has been found that micro-grain (submicron) rutile can promote rolling
wear even at concentrations as low as 3 % by volume.
As an alternative to mixing slurries, ready-mixed abrasive slurries can be used. If this is done, all details of the
supplier and makeup of the slurry shall be reported.
It is recommended that preliminary testing be undertaken to ensure that the slurry concentration chosen
produces the wear mode(s) of interest during the test.
6.4 Measurement of crater dimensions
Measurement of crater dimensions may be carried out with any suitable equipment, e.g. a microscope with
calibrated graticule, provided that the calibration used is traceable to national standards. Where
measurements are made from photographically captured images, it is essential that fiducial (reference) marks
of known dimensions are incorporated in the images to ensure that any shrinkage of the photographic film
after development or during storage can be eliminated. Alternatively, automatic measurement using an
electronically captured image may be used provided that the measurement system is fully calibrated, the
procedure used being traceable to national standards.
NOTE In some cases, e.g. rolling wear with relatively large abrasive particles, it has been found difficult to identify the
edges of craters, particularly at the outer surface of the coating. In such cases, the use of profilometry, a change in
illumination angle, or substrate etching (for craters that penetrate the coating) can help.
Profilometry may lead to results which are different from those obtained by optical-microscopy evaluation of
the crater size, due to rounded crater edges. Results of tests evaluated by different measurement methods
shall not be compared to each other.
4 © ISO 2008 – All ri
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