SIST EN ISO 14705:2021

Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for hardness of monolithic ceramics at room temperature (ISO 14705:2016)

ISO 14705:2016 specifies a test method for determining the Vickers and Knoop hardness of monolithic fine ceramics at room temperature.

Hochleistungskeramik - Härteprüfung von monolithischer Keramik bei Raumtemperatur (ISO 14705:2016)

Dieses Dokument legt ein Prüfverfahren zur Bestimmung der Härte von monolithischer Hochleistungskeramik bei Raumtemperatur nach Vickers und Knoop fest.

Céramiques techniques - Méthode d'essai de dureté des céramiques monolithiques à température ambiante (ISO 14705:2016)

Le présent document spécifie une méthode d'essai pour déterminer la dureté Vickers et Knoop des céramiques techniques monolithiques à température ambiante.

Fina keramika (sodobna keramika, sodobna tehnična keramika) - Preskus trdote za monolitno keramiko pri sobni temperaturi (ISO 14705:2016)

General Information

• Status: Published
• Public Enquiry End Date: 31-Oct-2020
• Publication Date: 31-Jan-2021
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 28-Jan-2021
• Due Date: 04-Apr-2021
• Completion Date: 01-Feb-2021
• Ref Project: EN ISO 14705:2021 - Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for hardness of monolithic ceramics at room temperature (ISO 14705:2016)

Relations

• Revises: oSIST prEN ISO 14705:2025 - Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for hardness of monolithic ceramics at room temperature (ISO/DIS 14705:2025)
• Effective Date: 19-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2021
Fina keramika (sodobna keramika, sodobna tehnična keramika) - Preskus trdote za
monolitno keramiko pri sobni temperaturi (ISO 14705:2016)
Fine ceramics (advanced ceramics, advanced technical ceramics) - Test method for
hardness of monolithic ceramics at room temperature (ISO 14705:2016)
Hochleistungskeramik - Härteprüfung von monolithischer Keramik bei Raumtemperatur
(ISO 14705:2016)
Céramiques techniques - Méthode d'essai de dureté des céramiques monolithiques à
température ambiante (ISO 14705:2016)
Ta slovenski standard je istoveten z: EN ISO 14705:2021
ICS:
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 14705
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2021
EUROPÄISCHE NORM
ICS 81.060.30
English Version
Fine ceramics (advanced ceramics, advanced technical
ceramics) - Test method for hardness of monolithic
ceramics at room temperature (ISO 14705:2016)
Céramiques techniques - Méthode d'essai de dureté Hochleistungskeramik - Härteprüfung von
des céramiques monolithiques à température ambiante monolithischer Keramik bei Raumtemperatur (ISO
(ISO 14705:2016) 14705:2016)
This European Standard was approved by CEN on 20 December 2020.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14705:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 14705:2016 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 14705:2021
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 July 2021, and conflicting national standards shall be
withdrawn at the latest by July 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 14705:2016 has been approved by CEN as EN ISO 14705:2021 without any modification.

INTERNATIONAL ISO
STANDARD 14705
Third edition
2016-12-15
Fine ceramics (advanced ceramics,
advanced technical ceramics) — Test
method for hardness of monolithic
ceramics at room temperature
Céramiques techniques — Méthode d’essai de dureté des céramiques
monolithiques à température ambiante
Reference number
ISO 14705:2016(E)
©
ISO 2016
ISO 14705:2016(E)
© 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

ISO 14705:2016(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Vickers hardness . 2
4.1 Principle . 2
4.2 Symbols, abbreviated terms and designations . 2
4.3 Significance and use . 4
4.4 Apparatus . 5
4.5 Test pieces . 5
4.6 Procedure . 5
4.7 Accuracy and uncertainties . 7
4.8 Test report . 8
5 Knoop hardness .11
5.1 Principle .11
5.2 Symbols and designations .11
5.3 Significance and use .13
5.4 Apparatus .14
5.5 Test pieces .14
5.6 Procedure .14
5.7 Accuracy and uncertainty .15
5.8 Test report .16
Bibliography .20
ISO 14705:2016(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.
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 third edition cancels and replaces the second edition (ISO 14705:2008), which has been technically
revised.
iv © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 14705:2016(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Test method for hardness of monolithic
ceramics at room temperature
1 Scope
This document specifies a test method for determining the Vickers and Knoop hardness of monolithic
fine ceramics at room temperature.
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 4545-1, Metallic materials — Knoop hardness test — Part 1: Test method
ISO 4545-2, Metallic materials — Knoop hardness test — Part 2: Verification and calibration of testing
machines
ISO 4545-4, Metallic materials — Knoop hardness test — Part 4: Table of hardness values
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6507-2, Metallic materials — Vickers hardness test — Part 2: Verification and calibration of testing
machines
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
Vickers hardness
value obtained by dividing the applied force by the surface area of the indentation computed from the
mean of the measured diagonals of the indentations, assuming that the indentation is an imprint of the
undeformed indenter
Note 1 to entry: Vickers hardness may be expressed in two different units:
a)  with unit GPa, obtained by dividing the applied force in N by the surface area of the indentation in mm ;
b) Vickers hardness number, obtained by dividing the applied force in kgf by the surface area of the
indentation in mm .
ISO 14705:2016(E)
3.2
Vickers indenter
indenter in the shape of a right-angle pyramid with a square base and an angle between opposite
faces of 136°
Note 1 to entry: See Table 1 and Figure 1.
3.3
Knoop hardness
value obtained by dividing the applied force by the projected area of the indentation computed from the
measurement of the long diagonal of the indentation, assuming that the indentation is an imprint of the
undeformed indenter
Note 1 to entry: The Knoop hardness may be expressed in two different units:
a)  with units of GPa, obtained by dividing the applied force in N by the projected area of the indentation in mm ;
b)  Knoop hardness number, obtained by dividing the applied force in kgf by the projected area of the indentation
in mm , without units specified.
3.4
Knoop indenter
indenter in the shape of a rhombic-based pyramid with the two angles between the opposite edges at
172,5° and 130°
Note 1 to entry: See Table 3 and Figure 6.
4 Vickers hardness
4.1 Principle
Forcing a diamond indenter in the form of a right-angle pyramid with a square base, and with a specified
angle between opposite faces at the vertex into the surface of a test piece and measuring the length of
the diagonals of the indentation left in the surface after removal of the test force, F. See Figure 1 and
Figure 2.
4.2 Symbols, abbreviated terms and designations
4.2.1 See Table 1, Figure 1 and Figure 2.
4.2.2 The Vickers hardness is denoted by the symbol HV, preceded by the hardness value and followed
by a number representing the test force (see Table 2).
Examples:
a)  Use of SI unit (GPa):
15,0 GPa HV 9,807 N represents a Vickers hardness of 15,0 GPa, determined with a test force of
9,807 N (1 kgf)
b)  Use of the Vickers hardness number (no units specified):
1 500 HV 1 represents a Vickers hardness number of 1 500, determined with a test force of 9,807 N
(1 kgf).
2 © ISO 2016 – All rights reserved

ISO 14705:2016(E)
Table 1 — Symbols, abbreviated terms and designations for Vickers hardness testing
Symbol or
abbreviated Designation
term
α Angle between the opposite faces at the vertex of the pyramidal indenter (136° ± 0,5°)
F Test force, in newtons
d Arithmetic mean, in millimetres, of the two diagonals, d and d
1 2
HV Vickers hardness
Test force
=×Constant
Surfaceareaofindentation
a)  Units of GPa
136°
2Fsin
F
=0,001 =0,001 854
d d
b)  Hardness number (no units specified)
136°
2Fsin
F
=0,102 =0,1891
d d
c Arithmetic mean of the half of the two median crack lengths, 2c and 2c
1 2
SD Standard deviation
HV −HV
()
∑ n
=
n−1
where
HV
∑ n
HV  is the arithmetic mean of the Vickers hardness = ;
n
HV  is the HV obtained from nth indentation;
n
n     is the number of indentations.
NOTE  Constant =0,102 , where g is the acceleration due to gravity.
g 9,807
Table 2 — Hardness symbols and the nominal values of test forces, F, for Vickers hardness testing
Test force, F
Hardness symbol
(nominal value)
HV 0,5 4,903 N
HV 1 9,807 N
HV 2 19,61 N
HV 3 29,42 N
HV 5 49,03 N
HV 10 98,07 N
HV 20 196,1 N
==
ISO 14705:2016(E)
Figure 1 — Vickers indenter (diamond pyramid)
Figure 2 — Vickers indentation
4.3 Significance and use
Vickers indentation diagonal lengths are approximately 2,8 times shorter than the long diagonal
of Knoop indentations, and the indentation depth is approximately 1,5 times deeper than Knoop
indentations made at the same force. Vickers indentations are influenced less by the specimen surface
flatness, parallelism of the diamond axis to the test piece surface normal, and surface finish than Knoop
indentations, but these parameters should be considered nonetheless. Vickers indentations are much
more likely to cause cracks in fine ceramics than Knoop indentations. Conversion between hardness
scales shall not be made.
Vickers indentations on metallic materials are mainly formed by the plastic deformation. However,
Vickers indentations on fine ceramics are formed by micro-cracking and micro-fracture, besides plastic
deformation. This difference shall be noted for comparing the hardness of metals and ceramics.
4 © ISO 2016 – All rights reserved

ISO 14705:2016(E)
4.4 Apparatus
4.4.1 Testing machine, capable of applying a predetermined test force in the range of 4,903 N (0,5 kgf)
to 98,07 N (10 kgf), preferably 9,807 N (1 kgf), in accordance with ISO 6507-2. Verification of the test
force shall be carried out in accordance with ISO 6507-2.
4.4.2 Diamond indenter, in the shape of a right-angle pyramid with a square base, as specified in
ISO 6507-1 and ISO 6507-2. Verification of the indenter shall be carried out in accordance with ISO 6507-2.
4.4.3 Measuring device, capable of measuring the indentation diagonals with a readout resolution
of ±0,2 µm or finer. A numerical aperture (NA) between 0,60 and 0,95 for the objective lens for the
microscope is recommended. Verification of the measuring device shall be carried out in accordance
with ISO 6507-2.
NOTE Indirect verification can be carried out by means of standardized blocks calibrated in accordance
with ISO 6507-3, following ISO 6507-2, or other approved and traceable ceramic standard reference blocks.
4.5 Test pieces
4.5.1 The test shall be carried out on a surface which is smooth, flat and free from foreign matter. The
test piece shall be polished to permit accurate measurement of the diagonal lengths of the indentation.
Preparation shall be carried out in such a way that any alteration of the surface hardness is minimized.
Surfaces shall not be thermally or chemically etched. If applicable, residual surface stresses shall be
removed by suitable polishing or annealing procedures.
4.5.2 The thickness of the test piece shall be at least 0,5 mm. It shall be at least 1,5 times the diagonal
of the indentation, d, and at least 2 times the crack length, c, whichever is greater. No indentation damage
shall be visible at the back of the test piece upon completion of the test.
4.6 Procedure
4.6.1 In general, the test shall be carried out at room temperature within the limits of 10 °C to 35 °C.
Tests carried out under controlled conditions shall be made at a temperature of 23 °C ± 5 °C.
4.6.2 The test force shall be 9,807 N (1 kgf). In cases where significant chipping or lateral crack-spalling
occurs or where the impression is too faint, the test forces within the range 4,903 N (0,5 kgf) to 196,1 N
(20 kgf), listed in Table 2, may be used. Other instances where a heavier load may be required are where
the grain structure is very coarse and the indentation area at lower loads may contact only a few grains
of the material (e.g. a multiphase material).
4.6.3 The following items shall be confirmed before the test.
a) Check the zero of the measuring system.
b) Check the measuring system using a calibrated scale or certified indentation in a test block.
c) Check the operation of the loading system by performing a test on a certified test block.
d) Check the condition of the indenter by examining the indentation made in the test block. Replace
the indenter, if necessary, by taking into account the conditions given in 4.6.10.
e) A test block with high hardness has to be used in order to obtain impressions in the same size
range as expected during tests on ceramics.
4.6.4 The indenter shall be cleaned prior to and during the test series, as ceramic powders or fragments
from the ceramic test piece can adhere to the diamond indenter.
ISO 14705:2016(E)
4.6.5 The test piece shall be placed on a rigid support. The support surface shall be clean and free from
foreign matter. It is important that the test piece lies firmly on the support, so that displacement cannot
occur during the test.
4.6.6 Carefully adjust the illumination and focusing conditions, in order to obtain the optimum view
and clarity of the indentation. Both indentation tips shall be in focus at the same time. Do not change the
focus when measuring the distance from tip to tip.
4.6.7 Bring the indenter into contact with the test surface and apply the test force in a direction
perpendicular to the surface, without shock or vibration, until the applied force attains the specified
value. The time from the initial application of the force until the full test force is reached shall not be less
than 1 s nor greater than 5 s. The duration of application of the constant maximum test force shall be 15 s.
4.6.8 Throughout the test, the apparatus shall be protected from shock or vibration.
4.6.9 The distance between the centre of any indentations and the edge of the test piece shall be at
least 2,5 times the mean diagonal of the indentation, and at least 5 times the mean length of the crack,
as shown in Figure 3. The distance between the centres of two adjacent indentations shall be at least
4 times the mean diagonal of the indentation, and at least 5 times the mean length of the crack, as shown
in Figure 3. If two adjacent indentations differ in size and crack length, the spacing shall be based on the
mean diagonal of the larger indentation and the longer crack length.
Key
1 edge of test piece
2 indentations
c length from the centre of indentation to the end of crack
d length of indent diagonal
l distance
...