ISO/ASTM FDIS 52940
(Main)Additive manufacturing of ceramics — Feedstock materials — Characterization of ceramic slurry in vat photopolymerization
Additive manufacturing of ceramics — Feedstock materials — Characterization of ceramic slurry in vat photopolymerization
This standard specifies the characterization of ceramic slurry for use as feedstock in vat photopolymerization additive manufacturing (AM) process. The characterization includes the composition and properties of the slurry, such as solids content, dynamic viscosity, particle size distribution, chemical composition, and solid dispersion stability. This standard also provides available methods about sampling and preparing slurry samples for testing. This standard does not deal with safety aspects.
Fabrication additive de céramiques — Matières premières — Caractérisation de la barbotine de céramique en photopolymérisation en cuve
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FINAL DRAFT
International
Standard
ISO/ASTM
FDIS
ISO/TC 261
Additive manufacturing of
Secretariat: DIN
ceramics — Feedstock materials —
Voting begins on:
Characterization of ceramic slurry
2025-08-20
in vat photopolymerization
Voting terminates on:
2025-10-15
Fabrication additive de céramiques — Matières premières
— Caractérisation de la barbotine de céramique en
photopolymérisation en cuve
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/ASTM
FDIS
ISO/TC 261
Additive manufacturing of
Secretariat: DIN
ceramics — Feedstock materials —
Voting begins on:
Characterization of ceramic slurry
in vat photopolymerization
Voting terminates on:
Fabrication additive de céramiques — Matières premières
— Caractérisation de la barbotine de céramique en
photopolymérisation en cuve
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
© ISO/ASTM International 2025
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
IN ADDITION TO THEIR EVALUATION AS
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
or ISO’s member body in the country of the requester. In the United States, such requests should be sent to ASTM International.
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
ISO copyright office ASTM International TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
CP 401 • Ch. de Blandonnet 8 100 Barr Harbor Drive, PO Box C700
CH-1214 Vernier, Geneva West Conshohocken, PA 19428-2959, USA
Phone: +41 22 749 01 11 Phone: +610 832 9634
Fax: +610 832 9635
Email: copyright@iso.org Email: khooper@astm.org
Website: www.iso.org Website: www.astm.org
Published in Switzerland Reference number
© ISO/ASTM International 2025 – All rights reserved
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling and preparation of test sample . 2
5 Slurry characterization . 2
5.1 Ceramics content .2
5.2 Dynamic viscosity.2
5.3 Particle size distribution .3
5.4 Chemical composition of ceramic powders.4
5.5 Solid dispersion stability .5
6 Test report . 5
Annex A (informative) Principle of the ceramics content. 7
Annex B (informative) Characteristics and observation methods for changes in dispersion
stability . 8
Bibliography . 9
© ISO/ASTM International 2025 – All rights reserved
iii
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 of the voluntary nature of standards, 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 261, Additive manufacturing, in cooperation
with ASTM Committee F42, Additive Manufacturing Technologies, on the basis of a partnership agreement
between ISO and ASTM International with the aim to create a common set of ISO/ASTM standards on
Additive Manufacturing, and in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 438, Additive manufacturing, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
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.
© ISO/ASTM International 2025 – All rights reserved
iv
FINAL DRAFT International Standard ISO/ASTM FDIS 52940:2025(en)
Additive manufacturing of ceramics — Feedstock materials —
Characterization of ceramic slurry in vat photopolymerization
1 Scope
This document specifies the characterization of ceramic slurry for use as feedstock in vat photopolymerization
additive manufacturing (AM) processes. The characterization includes the composition and properties of
the slurry, such as solids content, dynamic viscosity, particle size distribution, chemical composition, and
solid dispersion stability. This document also provides available methods on sampling and preparing slurry
samples for testing.
This document does not deal with safety aspects.
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 1513, Paints and varnishes — Examination and preparation of test samples
ISO 3252, Powder metallurgy — Vocabulary
ISO 8213, Chemical products for industrial use — Sampling techniques — Solid chemical products in the form of
particles varying from powders to coarse lumps
ISO 9276-1, Representation of results of particle size analysis — Part 1: Graphical representation
ISO 9276-2, Representation of results of particle size analysis — Part 2: Calculation of average particle sizes/
diameters and moments from particle size distributions
ISO 11358-1, Plastics — Thermogravimetry (TG) of polymers — Part 1: General principles
ISO 13097, Guidelines for the characterization of dispersion stability
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
ASTM B243, Standard Terminology of Powder Metallurgy
ASTM C242, Standard Terminology of Ceramic Whitewares and Related Products
ASTM C1145, Standard Terminology of Advanced Ceramics
ASTM D6370, Standard Test Method for Rubber — Compositional Analysis by Thermogravimetry (TGA)
ASTM D7348, Standard Test Methods for Loss on Ignition (LOI) of Solid Combustion Residues
ASTM E1131, Standard Test Method for Compositional Analysis by Thermogravimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3252, ISO/ASTM 52900, ASTM
B243, ASTM C242 and ASTM C1145 apply.
© ISO/ASTM International 2025 – All rights reserved
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Sampling and preparation of test sample
Test samples shall be representatives of the ceramic slurry product batch. The sampling methods and
devices for a certain quantity of ceramic slurry shall comply with the requirements mutually agreed upon
by the supplier and customer. The obtained samples shall be suitable for examination and preparation in
accordance with ISO 1513. The sampling procedure for testing raw ceramic powders prior to mixing with
photocurable resins shall comply with the requirements specified in ISO 8213; otherwise, the methods
specified in a suitable national standard, or another method mutually agreed upon by the supplier and
customer, shall be used.
The number of samples to be taken depends on the sampling plan (e.g. ISO 28590) or supply agreements. Test
samples shall be taken in consideration of the minimum sample amount as well as the repetitions required
in each test method. Preparation of test samples as well as all operations for subsequent characterization
tests are recommended to be performed under a UV-blocked laboratory environment.
5 Slurry characterization
5.1 Ceramics content
Ceramics content refers to the amount of ceramic powder in the total slurry. The amount of ceramic powder
that has been added during the slurry preparation process is expressed as mass fraction in SI unit (kg/kg)
or more commonly mass percentage (wt %). If the proportion of ceramic powder in test sample is unknown,
the ceramics content shall be estimated from the loss on ignition of ceramic slurry referring to ISO 11358-1,
ASTM D6370, ASTM D7348, and ASTM E1131 (see Annex A).
5.2 Dynamic viscosity
Dynamic viscosity describes the flow resistance of a fluid and is an important fluid property that is related
2 -1 -1
to the internal friction within the fluid. Dynamic viscosity is usually expressed in N·s/m , kg·m ·s , Pa·s (or
mPa·s) in SI unit, or P (or cP) in CGS unit.
X = shear rate in 1/s X = shear rate in 1/s
Y = viscosity (Pa s) Y = viscosity (Pa s)
a) Zirconia slurry b) Alumina slurry
© ISO/ASTM International 2025 – All rights reserved
Figure 1 — Examples of dynamic viscosity of the commercial AM ceramic slurries
Dynamic viscosity is the measurement of a fluids resistance to gradual deformation or movement caused
by shear or tensile stress, and it usually refers to the rheological property of a suspension slurry in ceramic
materials. The dynamic viscosity of a ceramic slurry in vat photopolymerization is affected by various
factors, such as ceramic powder contents, particle distribution and shapes, the types of resins, hydrodynamic
interactions between powders and resins, and slurry mixing conditions or aging time.
As shown in Figure 1, the dynamic viscosity of AM
...
ISO /TC 261
Secretariat: DIN
Date: 2025-07-14
Additive manufacturing of ceramics — Feedstock materials —
Characterization of ceramic slurry in vat photopolymerization
Fabrication additive de céramiques — Matières premières — Caractérisation de la barbotine de céramique en
photopolymérisation en cuve
FDIS stage
© ISO/ASTM 2025
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. In the United States, such requests should be
sent to ASTM International.
ISO copyright office ASTM International
CP 401 • Ch. de Blandonnet 8 100 Barr Harbor Drive, PO Box C700
CH-1214 Vernier, Geneva West Conshohocken, PA 19428-2959, USA
Phone: + 41 22 749 01 11 Phone: +610 832 9634
Fax: +41 22 749 09 47 Fax: +610 832 9635
Email: Email: khooper@astmE-mail: copyright@iso.org
Website: Website: : www.iso.org
Published in Switzerland
© ISO/ASTM 2025 – All rights reserved
ii
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling and preparation of test sample . 2
5 Slurry characterization . 2
5.1 Ceramics content . 2
5.2 Dynamic viscosity . 2
5.3 Particle size distribution . 4
5.4 Chemical composition of ceramic powders . 5
5.5 Solid dispersion stability . 5
6 Test report . 6
Annex A (informative) Principle of the ceramics content . 7
Annex B (informative) Characteristics and observation methods for changes in dispersion
stability . 8
Bibliography . 9
Foreword . iv
© ISO/ASTM 2025 – All rights reserved
iii
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 of the voluntary nature of standards, 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 261, Additive manufacturing, in cooperation
with ASTM Committee F42, Additive Manufacturing Technologies, on the basis of a partnership agreement
between ISO and ASTM International with the aim to create a common set of ISO/ASTM standards on Additive
Manufacturing, and in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 438, Additive manufacturing, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
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.
© ISO/ASTM 2025 – All rights reserved
iv
Additive manufacturing of ceramics — Feedstock materials —
Characterization of ceramic slurry in vat photopolymerization
1 Scope
This document specifies the characterization of ceramic slurry for use as feedstock in vat photopolymerization
additive manufacturing (AM) processes. The characterization includes the composition and properties of the
slurry, such as solids content, dynamic viscosity, particle size distribution, chemical composition, and solid
dispersion stability. This document also provides available methods on sampling and preparing slurry
samples for testing.
This document does not deal with safety aspects.
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 1513, Paints and varnishes — Examination and preparation of test samples
ISO 3252, Powder metallurgy — Vocabulary
ISO 8213, Chemical products for industrial use — Sampling techniques — Solid chemical products in the form of
particles varying from powders to coarse lumps
ISO 9276--1, Representation of results of particle size analysis — Part 1: Graphical representation
ISO 9276--2, Representation of results of particle size analysis — Part 2: Calculation of average particle
sizes/diameters and moments from particle size distributions
ISO 11358--1, Plastics — Thermogravimetry (TG) of polymers — Part 1: General principles
ISO 13097, Guidelines for the characterization of dispersion stability
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
ASTM B243, Standard Terminology of Powder Metallurgy
ASTM C242, Standard Terminology of Ceramic Whitewares and Related Products
ASTM C1145, Standard Terminology of Advanced Ceramics
ASTM D6370, Standard Test Method for Rubber — Compositional Analysis by Thermogravimetry (TGA))
ASTM D7348, Standard Test Methods for Loss on Ignition (LOI) of Solid Combustion Residues
ASTM E1131, Standard Test Method for Compositional Analysis by Thermogravimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3252, ISO/ASTM 52900, ASTM B243,
ASTM C242 and ASTM C1145 apply.
© ISO/ASTM 2025 – All rights reserved
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
4 Sampling and preparation of test sample
Test samples shall be representatives of the ceramic slurry product batch. The sampling methods and devices
for a certain quantity of ceramic slurry shall comply with the requirements mutually agreed upon by the
supplier and customer. The obtained samples shall be suitable for examination and preparation in accordance
with ISO 1513. The sampling procedure for testing raw ceramic powders prior to mixing with photocurable
resins shall comply with the requirements specified in ISO 8213; otherwise, the methods specified in a suitable
national standard, or another method mutually agreed upon by the supplier and customer, shall be used.
The number of samples to be taken depends on the sampling plan (e.g. ISO 28590) or supply agreements. Test
samples shall be taken in consideration of the minimum sample amount as well as the repetitions required in
each test method. Preparation of test samples as well as all operations for subsequent characterization tests
are recommended to be performed under a UV-blocked laboratory environment.
5 Slurry characterization
5.1 Ceramics content
Ceramics content refers to the amount of ceramic powder in the total slurry. The amount of ceramic powder
that has been added during the slurry preparation process is expressed as mass fraction in SI unit (kg/kg) or
more commonly mass percentage (wt. %). If the proportion of ceramic powder in test sample is unknown, the
ceramics content shall be estimated from the loss on ignition of ceramic slurry referring to ISO 11358-1, ASTM
D6370, ASTM D7348, and ASTM E1131 (see Annex AAnnex A).).
5.2 Dynamic viscosity
Dynamic viscosity describes the flow resistance of a fluid and is an important fluid property that is related to
2 -1 -1
the internal friction within the fluid. Dynamic viscosity is usually expressed in N·s/m , kg·m ·s , Pa·s (or
mPa·s) in SI unit, or P (or cP) in CGS unit.
52940_ed1fig1a.EPS 52940_ed1fig1b.EPS
X = shear rate in 1/s X = shear rate in 1/s
Y = viscosity (Pa s) Y = viscosity (Pa s)
a) Zirconia slurry b) Alumina slurry
© ISO/ASTM 2025 – All rights reserved
Figure 1 — Examples of dynamic viscosity of the commercial AM ceramic slurries
Dynamic viscosity is the measurement of a fluids resistance to gradual deformation or movement caused by
shear or tensile stress, and it usually refers to the rheological property of a suspension slurry in ceramic
materials. The dynamic viscosity of a ceramic slurry in vat photopolymerization is affected by various factors,
such as ceramic powder contents, particle distribution and shapes, the types of resins, hydrodynamic
interactions between powders and resins, and slurry mixing conditions or aging time.
As shown in Figure 1Figure 1,, the dynamic viscosity of AM ceramic slurry typically decreases due to the shear-
thinning effect, which occurs with increasing shear rate or decreasing shear stress. Therefore, both shear rate
and shear stress shall be considered when selecting an appropriate method for evaluating dynamic viscosity.
The dynamic viscosity of a ceramic slurry shall be determined in accordance with one or several of the
methods listed in Table 1Table 1,, or an alternative method mutually agreed upon by the supplier and the
customer.
Table 1 — Available testing standards for measuring the dynamic viscosity of ceramic slurry
StandardsStan
Type Method CharacteristicsCharacteristic
dard
— — Viscosity range from low to high viscosities
ISO 3219-2
— — Test method for ceramic slurry
ISO 19613
Cone and plate
-1
rheometer — — Shear rate limit: 500 s
ASTM D7395
-1 -1
— — Shear rate limit: 10 000 s ∼to 12 000 s
ASTM D4287
— — Viscosity range from low to high viscosities
ISO 3219-2
Coaxial–
cylinder — — Test method for ceramic slurry
ISO 19613
— — Viscosity range from low to high viscosities
Double-gap ISO 3219-2
— — Measuring of coarsely dispersed samples is possible
ISO 3219-2
— — Pastes, gels, or molten high-viscosity polymer sample
ISO 6721-10
Parallel-plate
Rotational
rheometer — — Test method for ceramic slurry
ISO 19613
— — Particle size limit: up to 250 μm
ASTM D7175
— — Viscosity: 0,02 Pa·s ∼to 60 000 Pa·s
ISO 2555
Brookfield
-1 -1
— — Shear rate limit: 0,1 s ∼to 50 s
ASTM D2196
— — Coaxial relative cylinder measuring geometries with a
radius ratio >1,1
ISO 3219-2
— — Relative measuring geometries with surface
Others
modification
— — Single cylinder viscometer
ISO 19613
— — Viscosity: 0,6 mPa·s ∼to 250 000 mPa·s
Falling ball Falling ball ISO 12058-1
© ISO/ASTM 2025 – All rights reserved
StandardsStan
Type Method CharacteristicsCharacteristic
dard
— — Temperature: - -20 °C ∼to 120 °C
— — Viscosity: greater than 1 Pa·s
ASTM D1343
— — Viscosity: up to 34 Pa·s
Disc spindle/
Disc or ball ISO 2884-2
Ball spindle — — Temperature: 23 °C ± 0,3 °C
5.3 Particle size distribution
Particle size distribution is expressed as v
...
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