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

ISO 19613:2018 specifies a method for measurement of the viscosity of a ceramic slurry using a rotational viscometer.

Céramiques techniques — Mesure de la viscosité des céramiques en suspension au moyen d'un viscosimètre rotatif

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Status
Published
Publication Date
05-Apr-2018
Technical Committee
Drafting Committee
Current Stage
6060 - International Standard published
Start Date
06-Apr-2018
Completion Date
06-Apr-2018
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ISO 19613:2018 - Fine ceramics (advanced ceramics, advanced technical ceramics) -- Measurement of viscosity of ceramic slurry by use of a rotational viscometer
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INTERNATIONAL ISO
STANDARD 19613
First edition
2018-04
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Measurement of viscosity of
ceramic slurry by use of a rotational
viscometer
Céramiques techniques — Mesure de la viscosité des céramiques en
suspension au moyen d'un viscosimètre rotatif
Reference number
ISO 19613:2018(E)
ISO 2018
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ISO 19613:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

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Published in Switzerland
ii © ISO 2018 – All rights reserved
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ISO 19613:2018(E)
Contents Page

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

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

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

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

4 Principle ........................................................................................................................................................................................................................ 3

4.1 Rotational viscometer with defined shear rate .......................................................................................................... 3

4.2 Single cylinder viscometer ............................................................................................................................................................ 3

5 Apparatus ..................................................................................................................................................................................................................... 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Rotational viscometer with defined shear rate. ......................................................................................................... 4

5.2.1 Measuring system ........................................................................................................................................................... 4

5.2.2 Basic capacity of the instrument ........................................................................................................................ 4

5.2.3 Installation of rotational viscometer .............................................................................................................. 4

5.3 Single cylinder viscometer. ........................................................................................................................................................... 5

5.3.1 Main body of single cylinder viscometer .................................................................................................... 5

5.3.2 Spindle ...................................................................................................................................................................................... 5

5.4 Temperature-control device........................................................................................................................................................ 5

5.4.1 Thermostat ........................................................................................................................................................................... 5

5.4.2 Thermometer ...................................................................................................................................................................... 5

6 Calibration of the rotational viscometer ..................................................................................................................................... 5

7 Measurement condition ................................................................................................................................................................................ 6

7.1 Temperature .............................................................................................................................................................................................. 6

7.2 Selection of geometry and/or spindle (shear rate or angular velocity) ................................................ 6

8 Pretreatment of the sample ...................................................................................................................................................................... 6

8.1 General ........................................................................................................................................................................................................... 6

8.2 Degassing ..................................................................................................................................................................................................... 6

8.3 Mixing and dispersion by ultrasonication ....................................................................................................................... 6

9 Measurement procedure .............................................................................................................................................................................. 7

9.1 Sampling ....................................................................................................................................................................................................... 7

9.2 Measurement at fixed shear rate or angular velocity ............................................................................................ 7

9.3 Repeat ............................................................................................................................................................................................................. 7

10 Expression of the results .............................................................................................................................................................................. 7

11 Test report ................................................................................................................................................................................................................... 7

Annex A (informative) Coaxial double cylinder system .................................................................................................................... 9

Annex B (informative) Cone and plate system .........................................................................................................................................12

Annex C (informative) Parallel plate system .............................................................................................................................................13

Annex D (informative) Single cylinder viscometer .............................................................................................................................15

Bibliography .............................................................................................................................................................................................................................18

© ISO 2018 – All rights reserved iii
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ISO 19613:2018(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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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

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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
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INTERNATIONAL STANDARD ISO 19613:2018(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Measurement of viscosity of ceramic slurry by
use of a rotational viscometer
1 Scope

This document specifies a method for measurement of the viscosity of a ceramic slurry using a

rotational viscometer.
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/IEC 17025, General requirements for the competence of testing and calibration laboratories

ISO 20507, Fine ceramics (advanced ceramics, advanced technical ceramics) — Vocabulary

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 20507 and the following 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

stress acting on planes parallel to the direction of flow when the fluid is subject to laminar flow

Note 1 to entry: The SI units are pascals (Pa).
3.2
shear rate
gradient of laminar flow rate perpendicular to the fluid flow
Note 1 to entry: The SI units are s .
3.3
viscosity
ratio of shear stress to shear rate

Note 1 to entry: This ratio is representative of the internal resistance of the fluid to flow.

Note 2 to entry: The SI unit of viscosity is Pa × s.

Note 3 to entry: mPa × s = 1 cP in terms of c.g.s. units [where 1 P = 1 g/(cm × s)].

Note 4 to entry: Viscosity is sometimes called ‘dynamic viscosity’ or ‘shear viscosity’ for clarification. The

measured viscosity is conventionally called ‘apparent viscosity’ since the gradient of shear rate is not identical

for all parts of the spindle.
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ISO 19613:2018(E)
3.4
Newtonian fluid
fluid in which shear stress is proportional to shear rate
Note 1 to entry: The ratio of shear stress to shear rate is viscosity.
3.5
non-Newtonian fluid
fluid in which shear stress is not proportional to shear rate

Note 1 to entry: The non-Newtonian behaviour can be determined by measuring shear stress using varying

shear rate (or angular velocity). Viscosity of the non-Newtonian fluid changes with the shear rate, in contrast

with Newtonian fluid, which has constant viscosity with the shear rate.
3.6
thixotropy

flow behaviour of fluid that shows time dependence, such that the apparent viscosity decreases with

time for a constant shear rate, and recovers slowly with withdrawal of the shear force

3.7
shear thickening

increase of shear viscosity of fluid when the shear rate (or stress) is increased

3.8
shear thinning

decrease of shear viscosity of fluid when the shear rate (or stress) is increased

3.9
Bingham plastic

linear shear stress/shear rate relationship starting from a finite yield stress value below which the

fluid does not flow
3.10
flow curve
curve showing the relationship between shear rate and shear stress
Note 1 to entry: See Figure 1 a).
3.11
viscosity curve

curve showing the relationship between shear rate (or shear stress) and viscosity

Note 1 to entry: See Figure 1 b).
3.12
ceramic slurry

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

Note 1 to entry: ceramic slurry is used in ceramic processes such as dip coating, spray coating, screen printing,

slip casting, tape casting, spray drying and polishing.

Note 2 to entry: The category may include low-viscosity colloids with small particles with sizes in the nanometre

or micrometre range, and high-viscosity pastes with inhomogeneous mixtures.
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ISO 19613:2018(E)
a) Flow curve b) Viscosity curve
Key
shear rate 2 shear thickening (dilatant)
τ shear stress 3 Newtonian
η viscosity 4 shear thinning (pseudoplastic)
1 Bingham plastic 5 thixotropy (time dependent)
Figure 1 — Summary of rheological behaviours
4 Principle
4.1 Rotational viscometer with defined shear rate

The viscosity, η, of a ceramic slurry measured using a rotational viscometer with a defined shear rate is

determined using Formula (1):
η = (1)
where
η is the viscosity, in Pa × s;
τ is the shear stress, in Pa;
 is the shear rate, in s .
NOTE Symbols are in accordance with ISO 80000-4.
4.2 Single cylinder viscometer

A spindle of cylindrical or disk-like shape is driven in the ceramic slurry at a fixed angular velocity.

Torque is developed from the fluid resistance, and it depends on the viscosity of the slurry. Theoretically,

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ISO 19613:2018(E)

shear rate (or shear stress) cannot be determined, but viscosity can be measured as a function of

angular velocity.

NOTE The gradient of shear rate is not identical for all parts of the spindle. Therefore, the measurement

result is conventionally called apparent viscosity because it is not the viscosity determined from the gradient of a

known shear rate.
5 Apparatus
5.1 General

Rotational viscometers have various measuring geometries. Representative rotational viscometers

having a defined shear rate are a coaxial cylinder system (Annex A), a cone and plate system (Annex B),

and a parallel plates system (Annex C). In contrast, single cylinder viscometers without a defined shear

rate (Annex D) are able to give an apparent viscosity relatively quickly and reproducibly, and to provide

a comparison between samples.
5.2 Rotational viscometer with defined shear rate.
5.2.1 Measuring system

The measuring system shall consist of two rigid, symmetrical, coaxial surfaces between which the fluid

whose viscosity is to be measured is placed. One of these surfaces shall rotate while the other remains

at rest. The measuring system shall be such that the shear rate can be defined for each measurement.

A torque-measuring device shall be connected to one of the surfaces, thus permitting determination of

the torque required to overcome the viscous resistance of the fluid. Suitable measuring systems are the

coaxial double cylinder system (Annex A), cone and plate system (Annex B), and parallel plate system

(Annex C), as prescribed by JIS 8803 and ISO 20507. The dimensions of each measuring system are

detailed in Annexes A, B, and C, which are designed to ensure a geometrically similar flow field for all

types of measurement and all common types of basic instrument.
5.2.2 Basic capacity of the instrument

The basic instrument shall be designed to permit alternative rotors and stators to be fitted, for the

generation of a range of defined rotational frequencies (stepwise or continuously variable), and for

measuring the resulting torque, or vice versa (i.e. measurement of the necessary angular velocity to

generate a defined torque). The apparatus shall have a torque-measurement accuracy of 2 % of the full-

scale reading. Within the regular working range of the instrument, the accuracy of rotational-frequency

measurement shall be 2 % of the measured value. The repeatability of viscosity measurement shall

be ±2 %.

NOTE By using different measuring systems and rotational frequencies, most commercial instruments

−2 3
cover a viscosity range of at least 10 Pa × s to 10 Pa × s.
5.2.3 Installation of rotational viscometer
5.2.3.1 Coaxial double cylinder viscometer
a) The axis of rotation of the viscometer is installed vertically.

b) The surface of the sample is maintained at a lower position than the surface of the thermostat or

the top of the liquid jacket in the outer cylinder.

c) The inner cylinder is placed with its axis coinciding with the axis of the outer cylinder; the distance

from the bottom of the inner cylinder to the bottom of the outer cylinder is more than 5 mm. The

upper surface of the inner cylinder is more than 5 mm below the surface of the sample.

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ISO 19613:2018(E)
5.2.3.2 Cone and plate viscometer

a) The axis of rotation of the viscometer is installed vertically, and the plate horizontally.

b) The surface of the sample is maintained at a lower position than the surface of the thermostat or

the top of the liquid jacket in cone and plate.

c) The cone is adjusted so its tip lies on the axis of rotation, and the centre of the parallel plate is also

positioned on the axis.

NOTE The tip of the cone may cause friction if it is in contact with the plate. The tip means the imaginary tip

of the cone obtained by extrapolation if the end is cut flat.
5.3 Single cylinder viscometer.

The single cylinder viscometer has two main components relevant to this standard.

5.3.1 Main body of single cylinder viscometer

It is necessary to select the proper model of viscometer for the viscosity to be measured, each model

being suited to a specific range of viscosities. Brookfield provides single cylinder viscometers that are

classified as LV (low viscosity), RV (medium viscosity) and HA/HB (high viscosity), as prescribed in

ISO 2555. Other manufacturers also provide equivalent systems. The suitable uses of cylinder-type

viscometers are also determined by special spindles such as Krebs or vane types. Some single cylinder

viscometers do not have a demarcation point between the body/shaft and spindle to define

...

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