ISO 20808:2016

Fine ceramics (advanced ceramics, advanced technical ceramics) - Determination of friction and wear characteristics of monolithic ceramics by ball-on-disc method

ISO 20808:2016 specifies a procedure for and provides guidance on the determination of the coefficient of friction and the specific wear rate for monolithic ceramics. In this method, the materials are tested in pairs, in a ball-on-disc configuration, under dry, non-abrasive conditions.

Céramiques techniques — Détermination des caractéristiques de frottement et d'usure des céramiques monolithiques par la méthode "bille sur disque"

General Information

• Status: Published
• Publication Date: 13-Jul-2016
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206 - Fine ceramics
• Current Stage: 9093 - International Standard confirmed
• Start Date: 03-Dec-2021
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 20808:2004 - Fine ceramics (advanced ceramics, advanced technical ceramics) - Determination of friction and wear characteristics of monolithic ceramics by ball-on-disc method
• Effective Date: 30-Nov-2013

Overview

ISO 20808:2016 specifies a standardized laboratory procedure - the ball-on-disc method - for determining the coefficient of friction and the specific wear rate of monolithic fine ceramics (advanced/technical ceramics). Tests are performed in pairs (ball vs. disc) under dry, non‑abrasive conditions to produce comparable friction and wear data for material selection, quality control and R&D.

Key topics and requirements

• Test configuration: ball-on-disc contact with the ball pressed against a rotating disc under constant load.
• Specimens:
  • Ball: true sphere >5 mm (recommended 10 mm); surface roughness ≤ 0.1 µm Ra (ISO 4287).
  • Disc: thickness >3 mm; sliding circle >30 mm diameter; flatness and parallelism within 0.02 mm (ISO 1101); surface roughness ≤ 0.1 µm Ra.
  • Ball and disc may be from the same or different ceramic materials; material details (composition, microstructure, heat treatments) must be reported.
• Apparatus & measurements:
  • Disc holder, drive system, rigid ball holder, controlled loading mechanism, friction transducer (accuracy ±1% of applied load), optional linear wear measurement (sensitivity ≤2.5 µm).
  • Environmental control: temperature ±2 °C, relative humidity 50 ± 10 %.
  • Ancillary equipment: balance (0.01 mg), micrometers, profilometer, micrometer microscope.
• Procedure essentials:
  • Pre-test cleaning (e.g., ultrasonic acetone rinse, hexane rinse, drying at 120 °C) and storage in test atmosphere.
  • Record specimen mass before/after test, measure wear scar on ball and wear track on disc, and calculate specific wear rate and coefficient of friction.
• Key metrics:
  • Coefficient of friction μ = Ff / Fp.
  • Specific wear rate Ws = V / (Fp × L) (wear volume V, normal force Fp, sliding distance L).
• Recommended conditions (example): applied load 10 N; sliding speed 0.1 m/s; but parameters can be adjusted and must be recorded.

Applications

• Comparative wear and friction evaluation for advanced ceramics used in bearings, seals, cutting tools, engine components, biomedical implants and high-temperature or corrosive environments.
• Material selection and qualification, process optimization, failure analysis, and R&D for new ceramic compositions or surface treatments.
• Establishing baseline tribological data for design engineers and quality labs.

Related standards

• ISO 4287 (surface texture), ISO 1101 (geometrical tolerancing), ISO 3611 (micrometers), ISO 3274 (profilometers), ISO 13385 (dimensional equipment), ISO/IEC 17025 (laboratory competence), ISO 80000‑1 (quantities and units). ISO 18754 referenced for alternative density determination.

Keywords: ISO 20808:2016, fine ceramics, advanced ceramics, ball-on-disc method, friction and wear testing, coefficient of friction, specific wear rate, monolithic ceramics.

Standards Content (Sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 20808
ISO/TC 206 Secretariat: JISC
Voting begins on: Voting terminates on:
2015-10-29 2016-01-29
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Determination of friction and wear
characteristics of monolithic ceramics by ball-on-disc
method
Céramiques techniques — Détermination des caractéristiques de frottement et d’usure des céramiques
monolithiques par la méthode “bille sur disque”
ICS: 81.060.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 20808:2015(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2015

ISO/DIS 20808:2015(E) ISO/DIS 20808

Contents Page
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Significance and use . 2
5 Test materials and specimen preparation . 2
5.1 Materials . 2
5.2 Ball specimen . 3
5.3 Disc specimen . 3
6 Apparatus . 3
7 Testing procedure . 4
7.1 Determination of specimen density . 4
7.2 Treatment of specimen before test . 4
7.3 Measurement of mass before test . 4
7.4 Preparation of wear test . 4
7.5 Testing conditions . 4
7.6 Measurement of friction force . 5
7.7 Measurement of mass after test . 5
7.8 Measurement of wear scar on ball specimen . 5
7.9 Measurement of wear track on disc specimen . 5
7.10 Number of test repeats . 5
8 Calculation of test results. 6
8.1 Specific wear rate of ball specimen . 6
8.1.1 Specific wear rate according to wear volume . 6
8.1.2 Specific wear rate according to mass loss . 8
8.2 Specific wear rate of disc specimen . 8
8.2.1 Specific wear rate according to wear volume . 8
8.2.2 Specific wear rate according to mass loss . 9
8.3 Coefficient of friction . 9
8.4 Rounding off of numerical values . 9
9 Test report . 9
Bibliography . 11

© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved
ISO/DIS 20808
Contents Page
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Significance and use . 2
5 Test materials and specimen preparation . 2
5.1 Materials . 2
5.2 Ball specimen . 3
5.3 Disc specimen . 3
6 Apparatus . 3
7 Testing procedure . 4
7.1 Determination of specimen density . 4
7.2 Treatment of specimen before test . 4
7.3 Measurement of mass before test . 4
7.4 Preparation of wear test . 4
7.5 Testing conditions . 4
7.6 Measurement of friction force . 5
7.7 Measurement of mass after test . 5
7.8 Measurement of wear scar on ball specimen . 5
7.9 Measurement of wear track on disc specimen . 5
7.10 Number of test repeats . 5
8 Calculation of test results. 6
8.1 Specific wear rate of ball specimen . 6
8.1.1 Specific wear rate according to wear volume . 6
8.1.2 Specific wear rate according to mass loss . 8
8.2 Specific wear rate of disc specimen . 8
8.2.1 Specific wear rate according to wear volume . 8
8.2.2 Specific wear rate according to mass loss . 9
8.3 Coefficient of friction . 9
8.4 Rounding off of numerical values . 9
9 Test report . 9
Bibliography . 11

ISO/DIS 20808
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 20808 was prepared by Technical Committee ISO/TC 206, Fine ceramics.
This second/third/. edition cancels and replaces the first/second/. edition (), [clause(s) / subclause(s) /
table(s) / figure(s) / annex(es)] of which [has / have] been technically revised.

iv © ISO 2015 – All rights reserved

DRAFT INTERNATIONAL STANDARD ISO/DIS 20808

Fine ceramics (advanced ceramics, advanced technical
ceramics) — Determination of friction and wear characteristics
of monolithic ceramics by ball-on-disc method
1 Scope
This International Standard specifies a procedure for and provides guidance on the determination of the
coefficient of friction and the specific wear rate for monolithic ceramics. In this method, the materials are
tested in pairs, in a ball-on-disc configuration, under dry, non-abrasive conditions.
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 31-0, Quantities and units — Part 0: General principles
ISO 1101, Geometrical Product Specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
ISO 3274, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Nominal
characteristics of contact (stylus) instruments
ISO 3599, Vernier callipers reading to 0,1 and 0,05 mm
ISO 3611, Micrometer callipers for external measurement
ISO 4287, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Terms, definitions
and surface texture parameters
ISO 18754, Fine ceramics (advanced ceramics, advanced technical ceramics) — Determination of density
and apparent porosity
3 Terms and definitions
For the purposes of this document the following terms and definitions apply.
3.1
wear
alteration of a solid surface by progressive loss or progressive displacement of material due to relative motion
between that surface and a contacting substance or substances
3.2
wear test
method of evaluating the friction and wear performance of materials in sliding contact
ISO/DIS 20808
3.3
ball-on-disc method
one of the wear test methods in which the sliding contact is brought about by pushing a ball specimen on to a
rotating disc specimen under a constant load
3.4
friction force
the resisting force tangential to the interface between two bodies when, under the action of an external force,
one body moves or tends to move relative to the other
3.5
coefficient of friction
µ
the dimensionless ratio of the friction force between the two bodies, F , to the normal force, F , pressing these
f p
bodies together
µ = F /F
f p
3.6
specific wear rate
W
s
Rate of material removal by wear defined as the quotient of wear volume, V, and the product of normal force,
F , and sliding distance, L, where
P
W =V/(F x L)
P
s
4 Significance and use
This International Standard gives guidance on conducting a sliding friction and wear test in a ball-on-disc
configuration. It shall be used to determine the wear resistance and friction generated in uniaxial sliding
contacts between ceramics.
It should be noted that there are many parameters in sliding contact that affect the magnitude of friction and
wear. The aim of performing any wear test is to simulate, as closely as possible, the conditions that occur in
the real application. As the deviation between the test conditions and the application conditions becomes
larger, the test results become less relevant. To add credence to the test results, the appearance of the worn
surfaces from the test samples shall be compared with the appea
...

INTERNATIONAL ISO
STANDARD 20808
Second edition
2016-07-15
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Determination of friction and wear
characteristics of monolithic ceramics
by ball-on-disc method
Céramiques techniques — Détermination des caractéristiques de
frottement et d’usure des céramiques monolithiques par la méthode
“bille sur disque”
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Significance and use . 2
5 Test materials and specimen preparation . 2
5.1 Materials . 2
5.2 Ball specimen . 3
5.3 Disc specimen . 3
6 Apparatus . 3
7 Testing procedure . 4
7.1 Determination of specimen density . . 4
7.2 Treatment of specimen before test . 4
7.3 Measurement of mass before test . 4
7.4 Preparation of wear test . 4
7.5 Testing conditions . 4
7.6 Measurement of friction force . 5
7.7 Measurement of mass after test . 5
7.8 Measurement of wear scar on ball specimen . 5
7.9 Measurement of wear track on disc specimen . 5
7.10 Number of test repeats . 5
8 Calculation of test results . 6
8.1 Specific wear rate of ball specimen . 6
8.1.1 Specific wear rate according to wear volume . 6
8.1.2 Specific wear rate according to mass loss . 8
8.2 Specific wear rate of disc specimen . 8
8.2.1 Specific wear rate according to wear volume . 8
8.2.2 Specific wear rate according to mass loss . 9
8.3 Coefficient of friction . 9
8.4 Rounding off of numerical values . 9
9 Test report .10
Bibliography .11
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.
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.
For an explanation on the meaning of ISO specific terms and 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 the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 206, Fine ceramics.
This second edition cancels and replaces the first edition (ISO 20808:2004), which has been technically
revised.
iv © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 20808:2016(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Determination of friction and wear
characteristics of monolithic ceramics by ball-on-disc
method
1 Scope
This document specifies a procedure for and provides guidance on the determination of the coefficient
of friction and the specific wear rate for monolithic ceramics. In this method, the materials are tested in
pairs, in a ball-on-disc configuration, under dry, non-abrasive conditions.
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 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form,
orientation, location and run-out
ISO 3274, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Nominal
characteristics of contact (stylus) instruments
ISO 3611, Geometrical product specifications (GPS) — Dimensional measuring equipment: Micrometers for
external measurements — Design and metrological characteristics
ISO 4287, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Terms, definitions
and surface texture parameters
ISO 13385 (all parts), Geometrical product specifications (GPS) — Dimensional measuring equipment
ISO 80000-1, Quantities and units — Part 1: General
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.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
wear
alteration of a solid surface by progressive loss or progressive displacement of material due to relative
motion between that surface and a contacting substance or substances
3.2
wear test
method of evaluating the friction and wear performance of materials in sliding contact
3.3
ball-on-disc method
wear test method in which the sliding contact is brought about by pushing a ball specimen on to a
rotating disc specimen under a constant load
3.4
friction force
resisting force tangential to the interface between two bodies when, under the action of an external
force, one body moves or tends to move relative to the other
3.5
coefficient of friction
µ
dimensionless ratio of the friction force between the two bodies, F , to the normal force, F , pressing
f p
these bodies together
F
f
μ =
F
p
3.6
specific wear rate
W
s
rate of material removal by wear defined as the quotient of wear volume, V, and the product of normal
force, F , and sliding distance, L
P
V
W =
s
()FL×
P
4 Significance and use
This document gives guidance on conducting a sliding friction and wear test in a ball-on-disc
configuration. It shall be used to determine the wear resistance and friction generated in uniaxial
sliding contacts between ceramics.
It should be noted that there are many parameters in sliding contact that affect the magnitude of friction
and wear. The aim of performing any wear test is to simulate, as closely as possible, the conditions
that occur in the real application. As the deviation between the test conditions and the application
conditions becomes larger, the test results become less relevant. To add credence to the test results, the
appearance of the worn surfaces from the test samples shall be compared with the appearance of the
worn surface from the actual worn component in order to ensure that similar wear mechanisms have
taken place in each case.
The recommended test conditions suggested in this document shall be used when the application
conditions are not well defined but general comparison among materials is required.
5 Test materials and specimen preparation
5.1 Materials
This test method can be applied to a variety of materials. The only requirement is that ball and disc
specimens having the dimensions specified below can be prepared, and that they shall withstand the
stresses imposed during the testing without failure or excessive flexure. In principle, the ball and disc
specimen should be from the same material, but ball and disc specimens from different materials can
also be tested by this method. Any pertinent details of the materials such as their dimensions, surface
finish, material type, composition, microstructure and processing treatments shall be reported.
2 © ISO 2016 – All rights reserved

5.2 Ball specimen
The ball specimen shall be a true sphere of more than 5 mm diameter, or a straight rod whose end
part is machined to a spherical cap. The recommended diameter of the sphere is 10 mm. The surface
roughness of the specimen shall be not more than 0,1 µm R as specified in ISO 4287.
a
5.3 Disc specimen
The disc specimen shall be more than 3 mm in thickness and be large enough to enable the testing
surface to contain a sliding circle of more than 30 mm diameter. The surfaces of the disc shall be flat
and parallel to within 0,02 mm as specified in ISO 1101. The roughness of the test surface shall be not
more than 0,1 µm R as specified in ISO 4287.
a
6 Apparatus
6.1 Ball-on-disc method testing apparatus.
The testing apparatus shall consist of the following:
— the disc holder, for securing a disc specimen;
— the dri
...