Fine ceramics (advanced ceramics, advanced technical ceramics) — Measurement of thixotropic behaviour of ceramic slurry by use of a rotational viscometer

ISO 20379:2018 specifies a method for measurement of thixotropic behaviour of ceramic slurry with rotational viscometer. The slurry with high-solid loading, which is used in ceramic manufacturing, has a generally non-Newtonian property. This method is limited to measurement of thixotropic behaviour of high-solid loaded ceramic slurry with "coaxial double cylinder viscometer", "cone and plate viscometer" and "a parallel plate viscometer" as rotational viscometers.

Céramiques techniques (céramiques avancées, céramiques techniques avancées) — Mesurage du comportement thixotropique d’une barbotine de céramique à l’aide d’un viscosimètre rotatif

General Information

Status
Published
Publication Date
12-Feb-2018
Technical Committee
Drafting Committee
Current Stage
6060 - International Standard published
Start Date
13-Feb-2018
Completion Date
13-Feb-2018
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ISO 20379:2018 - Fine ceramics (advanced ceramics, advanced technical ceramics) -- Measurement of thixotropic behaviour of ceramic slurry by use of a rotational viscometer
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INTERNATIONAL ISO
STANDARD 20379
First edition
2018-02
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Measurement of thixotropic behaviour
of ceramic slurry by use of a rotational
viscometer
Céramiques techniques (céramiques avancées, céramiques techniques
avancées) — Mesurage du comportement thixotropique d’une
barbotine de céramique à l’aide d’un viscosimètre rotatif
Reference number
ISO 20379:2018(E)
ISO 2018
---------------------- Page: 1 ----------------------
ISO 20379:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 20379:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 2

4.1 Evaluation of thixotropic behaviour by hysteresis measurement of flow curve ............................ 2

4.2 Evaluation of thixotropic behaviour by time-dependence of shear stress at

constant low shear rate ................................................................................................................................................................... 2

5 Apparatus ..................................................................................................................................................................................................................... 2

5.1 Measuring system ................................................................................................................................................................................. 2

5.2 Basic capacity of the instrument ............................................................................................................................................. 2

5.3 Calibration of rotational viscometer .................................................................................................................................... 3

5.4 Temperature control device ........................................................................................................................................................ 3

6 Pretreatment of the slurry samples ................................................................................................................................................. 3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Degassing ..................................................................................................................................................................................................... 3

6.3 Dispersion by stirring, mixing and ultrasonication................................................................................................. 3

7 Measurement condition ................................................................................................................................................................................ 3

7.1 Setting of ceramic slurry to rotational viscometer .................................................................................................. 3

7.2 Temperature .............................................................................................................................................................................................. 3

8 Measurement procedure .............................................................................................................................................................................. 4

8.1 Measurement of thixotropic behaviour by hysteresis measurement of flow curve .................... 4

8.1.1 Condition of shear rate and setting of measurement range ....................................................... 4

8.1.2 Measurement procedure ........................................................................................................................................... 4

8.1.3 Analysis method of measurement results .................................................................................................. 4

8.2 Measurement of thixotropic behaviour by time-dependence of shear stress at

constant low shear rate ................................................................................................................................................................... 5

8.2.1 Setting of measurement programme ............................................................................................................. 5

8.2.2 Measurement procedure ........................................................................................................................................... 5

8.2.3 Analysis method of measurement results .................................................................................................. 5

9 Test report ................................................................................................................................................................................................................... 6

Bibliography ................................................................................................................................................................................................................................ 8

© ISO 2018 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 20379:2018(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

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URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
iv © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 20379:2018(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Measurement of thixotropic behaviour of
ceramic slurry by use of a rotational viscometer
1 Scope

This document specifies a method for measurement of thixotropic behaviour of ceramic slurry with

rotational viscometer. The slurry with high-solid loading, which is used in ceramic manufacturing, has a

generally non-Newtonian property. This method is limited to measurement of thixotropic behaviour of

high-solid loaded ceramic slurry with “coaxial double cylinder viscometer”, “cone and plate viscometer”

and “a parallel plate viscometer” as rotational viscometers.
2 Normative references
There are no normative references in this document.
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
shear stress

force developed on the plane which is perpendicular to the shear force when there is shear applied to

the fluid
3.2
shear rate
proportion of laminar flow rate change perpendicular to the fluid flow
3.3
Newtonian property
slurry property of which the shear stress is proportional to the shear rate
3.4
non-Newtonian property
slurry property of which the shear stress is not proportional to the shear rate
3.5
viscosity
proportion of shear stress and shear rate
Note 1 to entry: The proportion is a representation of resistance to flow.
3.6
flow curve
curve showing the relationship between shear rate and shear stress
© ISO 2018 – All rights reserved 1
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ISO 20379:2018(E)
3.7
thixotropic behaviour

behaviour of fluid which has time-dependence of flow behaviour so that the apparent viscosity

decreases with time at controlled shear and recovers gradually with removal of the shear force

3.8
ceramic slurry

suspension of grinding ceramic powders mixed or dispersed in water or other liquid

Note 1 to entry: The suspension is used in the ceramic process, for example screen printing, slip casting, tape

casting, granule production.
4 Principle
4.1 Evaluation of thixotropic behaviour by hysteresis measurement of flow curve

Measurement of flow curve of ceramic slurry is performed using a rotational viscometer, which can

monitor shear rate and shear stress at the same time. The thixotropic behaviour is evaluated from the

magnitude of hysteresis that is indicated by the process of the flow curve.

4.2 Evaluation of thixotropic behaviour by time-dependence of shear stress at constant

low shear rate

Measurement of the flow curve of ceramic slurry is performed using a rotational viscometer, which

can monitor shear rate and shear stress at the same time. After the viscosity of ceramic slurry is

decreased by destruction of aggregated or flocculated structure in ceramic slurry at high shear rate,

the thixotropic behaviour is evaluated by measuring the recovery process of viscosity at low shear rate.

The relationship between fabrication of re-flocculated structure and time can be detected at low shear

rate. Therefore, the thixotropic behaviour is evaluated by using data from low shear rate.

5 Apparatus

A rotational viscometer has various measuring geometrics. In this document, the rotational viscometers

with defined shear rate are a coaxial double cylinder system, a cone and plate system and a parallel

plate system.
5.1 Measuring system
The measuring
...

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