Fine ceramics (advanced ceramics, advanced technical ceramics) — Methods for chemical analysis of zirconium oxide powders

This document specifies methods for the chemical analysis of zirconium oxide powders used as the raw material for fine ceramics. It stipulates the determination methods of the zirconium, aluminium, barium, calcium, cerium, cobalt, gadolinium, hafnium, iron, magnesium, potassium, silicon, sodium, strontium, titanium and yttrium contents in zirconium oxide powders for fine ceramics. The test sample is decomposed by acid pressure decomposition or alkali fusion. Contents of zirconium and yttrium are determined by using either a precipitation and gravimetric method or an inductively coupled plasma–optical emission spectrometry (ICP–OES) method. Contents of aluminium, barium, calcium, cerium, cobalt, gadolinium, hafnium, iron, magnesium, potassium, silicon, sodium, strontium and titanium are determined by using an ICP–OES method.

Céramiques techniques — Méthodes pour l'analyse chimique des poudres d'oxyde de zirconium

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Published
Publication Date
30-Aug-2021
Current Stage
6060 - International Standard published
Start Date
31-Aug-2021
Completion Date
31-Aug-2021
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INTERNATIONAL ISO
STANDARD 23739
First edition
2021-08
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Methods for chemical analysis of
zirconium oxide powders
Céramiques techniques — Méthodes pour l'analyse chimique des
poudres d'oxyde de zirconium
Reference number
ISO 23739:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 23739:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 23739:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

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

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

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

4 Analytes and ranges .......................................................................................................................................................................................... 1

5 Preparation of the test sample ............................................................................................................................................................... 2

5.1 General ........................................................................................................................................................................................................... 2

5.2 Sampling ....................................................................................................................................................................................................... 2

5.3 Drying ............................................................................................................................................................................................................. 2

5.4 Weighing ....................................................................................................................................................................................................... 2

6 Reporting the analytical values ............................................................................................................................................................. 2

6.1 Number of analyses............................................................................................................................................................................. 2

6.2 Blank test ..................................................................................................................................................................................................... 2

6.3 E valuation of the analytical values......................................................................................................................................... 2

6.4 Expression of analytical values ................................................................................................................................................. 3

7 Decomposition of the test sample ...................................................................................................................................................... 3

7.1 Classification of the sample decomposition methods ........................................................................................... 3

7.2 Acid pressure decomposition ..................................................................................................................................................... 3

7.2.1 Reagents .................................................................................................................................................................................. 3

7.2.2 Apparatus and instruments.................................................................................................................................... 3

7.2.3 Procedure ............................................................................................................................................................................... 4

7.2.4 Blank test ................................................................................................................................................................................ 4

7.3 Alkali fusion ............................................................................................................................................................................................... 5

7.3.1 Reagents .................................................................................................................................................................................. 5

7.3.2 Apparatus and instruments.................................................................................................................................... 5

7.3.3 Procedure ............................................................................................................................................................................... 5

7.3.4 Blank test ................................................................................................................................................................................ 5

8 Determination of the zirconium content ..................................................................................................................................... 6

8.1 Precipitation and gravimetric method ............................................................................................................................... 6

8.1.1 Principle .................................................................................................................................................................................. 6

8.1.2 Reagents .................................................................................................................................................................................. 6

8.1.3 Apparatus and instruments.................................................................................................................................... 6

8.1.4 Procedure ............................................................................................................................................................................... 6

8.1.5 Blank test ................................................................................................................................................................................ 7

8.1.6 Calculation ............................................................................................................................................................................. 7

8.2 ICP–OES method .................................................................................................................................................................................... 7

8.2.1 Principle .................................................................................................................................................................................. 7

8.2.2 Reagents .................................................................................................................................................................................. 7

8.2.3 Apparatus and instruments.................................................................................................................................... 7

8.2.4 Procedure ............................................................................................................................................................................... 7

8.2.5 Blank test ................................................................................................................................................................................ 8

8.2.6 Drawing of calibration curve ................................................................................................................................. 8

8.2.7 Calculation ............................................................................................................................................................................. 8

9 Determination of the major elements contents ................................................................................................................... 8

9.1 Precipitation and gravimetric method (for yttrium) ............................................................................................. 8

9.1.1 Principle .................................................................................................................................................................................. 8

9.1.2 Reagents .................................................................................................................................................................................. 8

9.1.3 Apparatus and instruments.................................................................................................................................... 8

9.1.4 Procedure ............................................................................................................................................................................... 9

9.1.5 Blank test ................................................................................................................................................................................ 9

9.1.6 Calculation ............................................................................................................................................................................. 9

© ISO 2021 – All rights reserved iii
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ISO 23739:2021(E)

9.2 ICP–OES method (for calcium, hafnium, magnesium and yttrium) .......................................................... 9

9.2.1 Principle .................................................................................................................................................................................. 9

9.2.2 Reagents .................................................................................................................................................................................. 9

9.2.3 Apparatus and instruments.................................................................................................................................10

9.2.4 Procedure ............................................................................................................................................................................10

9.2.5 Blank test .............................................................................................................................................................................10

9.2.6 Drawing of calibration curve ..............................................................................................................................10

9.2.7 Calculation ..........................................................................................................................................................................11

10 Determination of the trace elements contents ..................................................................................................................11

10.1 Principle .....................................................................................................................................................................................................11

10.2 Reagents.....................................................................................................................................................................................................11

10.2.1 Elemental standard solution ..............................................................................................................................11

10.2.2 Mixed standard solution (each element 50 mg/l) ...........................................................................12

10.3 Apparatus and instruments ......................................................................................................................................................12

10.4 Procedure .................................................................................................................................................................................................12

10.5 Blank test ..................................................................................................................................................................................................13

10.6 Drawing of the calibration curve ..........................................................................................................................................13

10.7 Calculation ...............................................................................................................................................................................................13

11 Test report ................................................................................................................................................................................................................14

Annex A (informative) Analytical results obtained from the interlaboratory test ............................................15

Bibliography .............................................................................................................................................................................................................................16

iv © ISO 2021 – All rights reserved
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ISO 23739:2021(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 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 206, Fine ceramics.

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 2021 – All rights reserved v
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INTERNATIONAL STANDARD ISO 23739:2021(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Methods for chemical analysis of zirconium
oxide powders
1 Scope

This document specifies methods for the chemical analysis of zirconium oxide powders used as the raw

material for fine ceramics.

It stipulates the determination methods of the zirconium, aluminium, barium, calcium, cerium, cobalt,

gadolinium, hafnium, iron, magnesium, potassium, silicon, sodium, strontium, titanium and yttrium

contents in zirconium oxide powders for fine ceramics. The test sample is decomposed by acid pressure

decomposition or alkali fusion. Contents of zirconium and yttrium are determined by using either a

precipitation and gravimetric method or an inductively coupled plasma–optical emission spectrometry

(ICP–OES) method. Contents of aluminium, barium, calcium, cerium, cobalt, gadolinium, hafnium, iron,

magnesium, potassium, silicon, sodium, strontium and titanium are determined by using an ICP–OES

method.
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 835, Laboratory glassware — Graduated pipettes
ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 8656-1, Refractory products — Sampling of raw materials and unshaped products — Part 1: Sampling

scheme
3 Terms and definitions
No terms and definitions are listed in this document.

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 http:// www .electropedia .org/
4 Analytes and ranges
— Zirconium (Zr), range of 60 % to 74 % (mass fraction).
— Aluminium (Al), range of 0,01 % to 0,5 % (mass fraction).
— Barium (Ba), range of 0,01 % to 0,5 % (mass fraction).
— Calcium (Ca), range of 0,01 % to 6 % (mass fraction).
— Cerium (Ce), range of 0,01 % to 0,5 % (mass fraction).
— Cobalt (Co), range of 0,01 % to 0,5 % (mass fraction).
© ISO 2021 – All rights reserved 1
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ISO 23739:2021(E)
— Gadolinium (Gd), range of 0,01 % to 0,5 % (mass fraction).
— Hafnium (Hf), range of 0,01 % to 2 % (mass fraction).
— Iron (Fe), range of 0,01 % to 0,5 % (mass fraction).
— Magnesium (Mg), range of 0,01 % to 6 % (mass fraction).
— Potassium (K), range of 0,01 % to 0,5 % (mass fraction).
— Sodium (Na), range of 0,01 % to 0,5 % (mass fraction).
— Silicon (Si), range of 0,01 % to 0,5 % (mass fraction).
— Strontium (Sr), range of 0,01 % to 0,5 % (mass fraction).
— Titanium (Ti), range of 0,01 % to 0,5 % (mass fraction).
— Yttrium (Y), range of 0,01 % to 15 % (mass fraction).
5 Preparation of the test sample
5.1 General

The sample preparation method shall be in accordance with ISO 8656-1, unless otherwise mutually

agreed upon by the analyser and customer.
5.2 Sampling
The sample shall be collected in accordance with ISO 8656-1.
5.3 Drying

Place 10 g of the sample into a flat-type weighing bottle (60 mm × 30 mm) and spread it uniformly over

the bottom of the bottle. Place the bottle in an air bath at 110 °C ± 5 °C for 2 h, uncovered, and cool in a

desiccator, covered, for 1 h.
5.4 Weighing

Weigh the test sample to the nearest 0,1 mg of the required quantity using a balance.

6 Reporting the analytical values
6.1 Number of analyses
Analyse the test sample twice on different days.
6.2 Blank test
Upon analysis, perform a blank test to correct the measured values.
6.3 E valuation of the analytical values

When the difference between the two analytical values does not exceed the tolerance value (Table 1),

the average value shall be reported. When the difference between the two analytical values exceeds the

tolerance value, perform two additional analyses. When the difference of these further two analyses

does not exceed the tolerance value, the average value thereof shall be reported. If the difference also

exceeds the tolerance value, the median of four analytical values shall be reported.

2 © ISO 2021 – All rights reserved
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ISO 23739:2021(E)
Table 1 — Tolerances for the analytical values
Units: % (mass fraction)
Component Zr Ca, Hf, Mg, Y Al, Ba, Ce, Co, Gd, Fe, K, Na, Si, Sr, Ti
0,01
Tolerance 0,70 0,01
0,1
Applicable to content of less than 0,1 %.
Applicable to content of not less than 0,1 %.
6.4 Expression of analytical values

The analytical values shall be given in % (mass fraction) in dryness. The results shall be expressed to

two decimal places (see Annex A).
7 Decomposition of the test sample
7.1 Classification of the sample decomposition methods
a) Acid pressure decomposition.

b) Alkali fusion, for the determination of the contents of major elements such as zirconium, calcium,

hafnium, magnesium and yttrium, and also for the determination of silicon content.

7.2 Acid pressure decomposition
7.2.1 Reagents

It shall be ascertained that the reagents are of sufficiently high purity to permit their use without

compromising the accuracy of the determination.
7.2.1.1 Water, grade 1 or superior as specified in ISO 3696.
7.2.1.2 Sulfuric acid (1+1).
7.2.2 Apparatus and instruments
Use ordinary laboratory apparatus and instruments together with the following:

7.2.2.1 Pressure decomposition vessel. A pressure decomposition vessel is shown in Figure 1. Use

the vessel exclusively for this analysis to avoid cross-contamination.
7.2.2.2 Polytetrafluoroethylene (PTFE) bottle, with cap.
© ISO 2021 – All rights reserved 3
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ISO 23739:2021(E)
7.2.2.3 Air bath, capable of heating at 230 °C ± 5 °C.
Key
1 centre screw
2 screw cap
3 top plate
4 PTFE cap
5 cylinder
6 PTFE bottle
7 bottom plate
Figure 1 — Example of a pressure decomposition vessel
7.2.3 Procedure

Weigh 0,2 g of the test sample in a polytetrafluoroethylene bottle (7.2.2.2) and add 10 ml of sulfuric acid

(1+1). Put the PTFE bottle into a pressure decomposition vessel (7.2.2.1) and close the vessel according

to the manufacturer's instructions. Place the vessel in an air bath and heat it at 230 °C ± 5 °C for 16 h.

After cooling, disassemble the vessel and transfer the dissolved solution to a 150-ml beaker. Wash the

bottle six times with approximately 10 ml of warm water each time and collect the washings into the

beaker. Transfer the solution into a 200-ml volumetric flask, dilute it with water up to the mark and mix

well. This solution is designated as the sample solution.
7.2.4 Blank test

Perform the operation described in 7.2.3 without taking a sample to obtain the blank test value. The

resulting solution is designated as blank test solution.
4 © ISO 2021 – All rights reserved
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ISO 23739:2021(E)
7.3 Alkali fusion
7.3.1 Reagents

It shall be ascertained that the reagents are of sufficiently high purity to permit their use without

compromising the accuracy of the determination.
7.3.1.1 Water, grade 1 or superior as specified in ISO 3696.

7.3.1.2 Lithium tetraborate (Li B O ), powdery, more than 99,995 % purity by trace metal basis.

2 4 7

Some commercial products of lithium tetraborate can contain certain impurities such as calcium,

potassium, silicon and sodium. Check their conformity with the test before use.
7.3.1.3 Hydrochloric acid (35 %, mass fraction).
7.3.2 Apparatus and instruments
Use ordinary laboratory apparatus and instruments together with the following:

7.3.2.1 Platinum crucible (30 ml), heated at 1 200 °C ± 50 °C for 15 min, and then cooled down to

room temperature in a desiccator.
7.3.2.2 Platinum lid.
7.3.2.3 Electric furnace, capable of being operated at 1 300 °C.
7.3.2.4 Ultrasonic bath.
7.3.3 Procedure

Mix 0,2 g of the test sample and 1,0 g of lithium tetraborate (7.3.1.2) in a platinum crucible (7.3.2.1).

Add 1,0 g of lithium tetraborate to the mixed sample. After covering the crucible with a platinum lid

(7.3.2.2), place the crucible in an electric furnace (7.3.2.3).

Raise the temperature of the furnace gradually and heat the crucible at 1 200 °C ± 50 °C until the

contents are completely decomposed.
Remove the crucible from the furnace and cool it to room temperature.

Put the crucible and the platinum lid into a 150-ml beaker containing 20 ml of hydrochloric acid (7.3.1.3)

and 100 ml of water (7.3.1.1). Covering the beaker with a watch glass, warm the beaker in an ultrasonic

bath (7.3.2.4) until the melt is completely dissolved into the solution.

Remove the beaker from the ultrasonic bath. Wash the watch glass, the crucible and the platinum lid

several times with approximately 50 ml of water and collect the washings into the beaker. After cooling,

transfer the solution into a 200-ml volumetric flask, dilute it with water up to the mark and mix well.

This is designated as the sample solution.
7.3.4 Blank test

Perform the operation described in 7.3.3 without taking a sample to obtain the blank test value. The

resulting solution is designated as blank test solution.
© ISO 2021 – All rights reserved 5
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ISO 23739:2021(E)
8 Determination of the zirconium content
8.1 Precipitation and gravimetric method
8.1.1 Principle

Zirconium with hafnium in the sample solution is precipitated by adding DL-mandelic acid solution.

After igniting the precipitate, the mass of the zirconium oxide (ZrO ) and hafnium oxide (HfO ) is

2 2

measured. The zirconium content is calculated from the mass of zirconium oxide as well as the hafnium

oxide content.
8.1.2 Reagents

It shall be ascertained that the reagents are of sufficiently high purity to permit their use without

compromising the accuracy of the determination.
8.1.2.1 Water, grade 1 or superior as specified in ISO 3696.
8.1.2.2 Hydrochloric acid (35 %, mass fraction).
8.1.2.3 DL-mandelic acid.

8.1.2.4 DL-mandelic acid solution (1 M), dissolve 152,15 g DL-mandelic acid (8.1.2.3) in 1 000 ml of

warm water.

8.1.2.5 Washing solution, dissolve 10 g DL-mandelic acid (8.1.2.3) in 200 ml of warm water and 4 ml

of hydrochloric acid (8.1.2.2).
8.1.3 Apparatus and instruments

Use the apparatus and instruments described in 7.3.2 together with the following:

8.1.3.1 Glass volumetric pipette, 50 ml, Class A, according to ISO 835.
8.1.3.2 Filter paper (ashless), diameter 110 mm, pore size index 8 µm.
8.1.3.3 Hot plate, with magnetic stirrer, capable of being operated at 450 °C.
8.1.4 Procedure

Transfer 50 ml of the sample solution (7.2.3 or 7.3.3) using a volumetric pipette (8.1.3.1) into a 500-ml

beaker. After adding 25 ml of hydrochloric acid (8.1.2.2) to the beaker, heat the solution to 90 °C on a hot

plate. While stirring the solution, add 50 ml of DL-mandelic acid solution (8.1.2.4). Covering the beaker

with a watch glass, heat the beaker at 90 °C for 1h. Wash the watch glass with approximately 30 ml of

warm water and add the washings into the beaker. Filter the solution using a filter paper (8.1.3.2) and

wash the precipitate several times with hot washing solution (8.1.2.5).

Weigh the mass of a platinum crucible (7.3.2.1) to the nearest 0,1 mg. Put the used filter paper and the

precipitate into the crucible and place the crucible in an electric furnace (7.3.2.3). Raise the temperature

of the furnace gradually and ignite the contents at (1 050 ± 50) °C for 30 min.

Remove the crucible from the furnace and cool it in a desiccator. After weighing the mass of the crucible

and the contents to the nearest 0,1 mg, calculate the mass of the precipitate.
6 © ISO 2021 – All rights reserved
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ISO 23739:2021(E)
8.1.5 Blank test

Perform the operation described in 8.1.4 with the blank test solution (7.2.4 or 7.3.4).

8.1.6 Calculation
Calculate the zirconium content, w , from Formula (1).
w = [(m – m )/m × 200/50 × 100 – w × F ] × F (1)
Zr i 0 s Hf 1 2
where
w is the zirconium content, in % (mass fraction);
m is the mass of the precipitate in the sample solution (7.2.3 or 7.3.3), in g;

m is the mass of the precipitate in the blank test solution (7.2.4 or 7.3.4), in g;

m is the mass of the test sample (7.2.3 or 7.3.3), in g;

w is the hafnium content calculated from Formula (4) or Formula (5), in % (mass fraction);

...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 23739
ISO/TC 206
Fine ceramics (advanced ceramics,
Secretariat: JISC
advanced technical ceramics) —
Voting begins on:
2021­06­02 Methods for chemical analysis of
zirconium oxide powders
Voting terminates on:
2021­07­28
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
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 23739:2021(E)
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. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 23739:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 23739:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

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

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

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

4 Analytes and ranges .......................................................................................................................................................................................... 1

5 Preparation of the test sample ............................................................................................................................................................... 2

5.1 General ........................................................................................................................................................................................................... 2

5.2 Sampling ....................................................................................................................................................................................................... 2

5.3 Drying ............................................................................................................................................................................................................. 2

5.4 Weighing ....................................................................................................................................................................................................... 2

6 Reporting the analytical values ............................................................................................................................................................. 2

6.1 Number of analyses............................................................................................................................................................................. 2

6.2 Blank test ..................................................................................................................................................................................................... 2

6.3 E valuation of the analytical values......................................................................................................................................... 2

6.4 Expression of analytical values ................................................................................................................................................. 3

7 Decomposition of the test sample ...................................................................................................................................................... 3

7.1 Classification of the sample decomposition methods ........................................................................................... 3

7.2 Acid pressure decomposition ..................................................................................................................................................... 3

7.2.1 Reagents .................................................................................................................................................................................. 3

7.2.2 Apparatus and instruments.................................................................................................................................... 3

7.2.3 Procedure ............................................................................................................................................................................... 4

7.2.4 Blank test ................................................................................................................................................................................ 4

7.3 Alkali fusion ............................................................................................................................................................................................... 5

7.3.1 Reagents .................................................................................................................................................................................. 5

7.3.2 Apparatus and instruments.................................................................................................................................... 5

7.3.3 Procedure ............................................................................................................................................................................... 5

7.3.4 Blank test ................................................................................................................................................................................ 5

8 Determination of the zirconium content ..................................................................................................................................... 6

8.1 Precipitation and gravimetric method ............................................................................................................................... 6

8.1.1 Principle .................................................................................................................................................................................. 6

8.1.2 Reagents .................................................................................................................................................................................. 6

8.1.3 Apparatus and instruments.................................................................................................................................... 6

8.1.4 Procedure ............................................................................................................................................................................... 6

8.1.5 Blank test ................................................................................................................................................................................ 7

8.1.6 Calculation ............................................................................................................................................................................. 7

8.2 ICP–OES method .................................................................................................................................................................................... 7

8.2.1 Principle .................................................................................................................................................................................. 7

8.2.2 Reagents .................................................................................................................................................................................. 7

8.2.3 Apparatus and instruments.................................................................................................................................... 7

8.2.4 Procedure ............................................................................................................................................................................... 7

8.2.5 Blank test ................................................................................................................................................................................ 8

8.2.6 Drawing of calibration curve ................................................................................................................................. 8

8.2.7 Calculation ............................................................................................................................................................................. 8

9 Determination of the major elements contents ................................................................................................................... 8

9.1 Precipitation and gravimetric method (for yttrium) ............................................................................................. 8

9.1.1 Principle .................................................................................................................................................................................. 8

9.1.2 Reagents .................................................................................................................................................................................. 8

9.1.3 Apparatus and instruments.................................................................................................................................... 8

9.1.4 Procedure ............................................................................................................................................................................... 9

9.1.5 Blank test ................................................................................................................................................................................ 9

9.1.6 Calculation ............................................................................................................................................................................. 9

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ISO/FDIS 23739:2021(E)

9.2 ICP–OES method (for calcium, hafnium, magnesium and yttrium) .......................................................... 9

9.2.1 Principle .................................................................................................................................................................................. 9

9.2.2 Reagents .................................................................................................................................................................................. 9

9.2.3 Apparatus and instruments.................................................................................................................................10

9.2.4 Procedure ............................................................................................................................................................................10

9.2.5 Blank test .............................................................................................................................................................................10

9.2.6 Drawing of calibration curve ..............................................................................................................................10

9.2.7 Calculation ..........................................................................................................................................................................11

10 Determination of the trace elements contents ..................................................................................................................11

10.1 Principle .....................................................................................................................................................................................................11

10.2 Reagents.....................................................................................................................................................................................................11

10.2.1 Elemental standard solution ..............................................................................................................................11

10.2.2 Mixed standard solution (each element 50 mg/l) ...........................................................................12

10.3 Apparatus and instruments ......................................................................................................................................................12

10.4 Procedure .................................................................................................................................................................................................12

10.5 Blank test ..................................................................................................................................................................................................13

10.6 Drawing of the calibration curve ..........................................................................................................................................13

10.7 Calculation ...............................................................................................................................................................................................13

11 Test report ................................................................................................................................................................................................................14

Annex A (informative) Analytical results obtained from the interlaboratory test ............................................15

Bibliography .............................................................................................................................................................................................................................16

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ISO/FDIS 23739:2021(E)
Foreword

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bodies (ISO member bodies). The work of preparing International Standards is normally carried out

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electrotechnical standardization.

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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).

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on the ISO list of patent declarations received (see www .iso .org/ patents).

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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.

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 2021 – All rights reserved v
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 23739:2021(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Methods for chemical analysis of zirconium
oxide powders
1 Scope

This document specifies methods for the chemical analysis of zirconium oxide powders used as the raw

material for fine ceramics.

It stipulates the determination methods of the zirconium, aluminium, barium, calcium, cerium, cobalt,

gadolinium, hafnium, iron, magnesium, potassium, silicon, sodium, strontium, titanium and yttrium

contents in zirconium oxide powders for fine ceramics. The test sample is decomposed by acid pressure

decomposition or alkali fusion. Contents of zirconium and yttrium are determined by using either a

precipitation and gravimetric method or an inductively coupled plasma–optical emission spectrometry

(ICP–OES) method. Contents of aluminium, barium, calcium, cerium, cobalt, gadolinium, hafnium, iron,

magnesium, potassium, silicon, sodium, strontium and titanium are determined by using an ICP–OES

method.
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 835, Laboratory glassware — Graduated pipettes
ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 8656­1, Refractory products — Sampling of raw materials and unshaped products — Part 1: Sampling

scheme
3 Terms and definitions
No terms and definitions are listed in this document.

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/
4 Analytes and ranges
— Zirconium (Zr), range of 60 % to 74 % (mass fraction).
— Aluminium (Al), range of 0,01 % to 0,5 % (mass fraction).
— Barium (Ba), range of 0,01 % to 0,5 % (mass fraction).
— Calcium (Ca), range of 0,01 % to 6 % (mass fraction).
— Cerium (Ce), range of 0,01 % to 0,5 % (mass fraction).
— Cobalt (Co), range of 0,01 % to 0,5 % (mass fraction).
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ISO/FDIS 23739:2021(E)
— Gadolinium (Gd), range of 0,01 % to 0,5 % (mass fraction).
— Hafnium (Hf), range of 0,01 % to 2 % (mass fraction).
— Iron (Fe), range of 0,01 % to 0,5 % (mass fraction).
— Magnesium (Mg), range of 0,01 % to 6 % (mass fraction).
— Potassium (K), range of 0,01 % to 0,5 % (mass fraction).
— Sodium (Na), range of 0,01 % to 0,5 % (mass fraction).
— Silicon (Si), range of 0,01 % to 0,5 % (mass fraction).
— Strontium (Sr), range of 0,01 % to 0,5 % (mass fraction).
— Titanium (Ti), range of 0,01 % to 0,5 % (mass fraction).
— Yttrium (Y), range of 0,01 % to 15 % (mass fraction).
5 Preparation of the test sample
5.1 General

The sample preparation method shall be in accordance with ISO 8656-1, unless otherwise mutually

agreed upon by the analyser and customer.
5.2 Sampling
The sample shall be collected in accordance with ISO 8656­1.
5.3 Drying

Place 10 g of the sample into a flat-type weighing bottle (60 mm × 30 mm) and spread it uniformly over

the bottom of the bottle. Place the bottle in an air bath at 110 °C ± 5 °C for 2 h, uncovered, and cool in a

desiccator, covered, for 1 h.
5.4 Weighing

Weigh the test sample to the nearest 0,1 mg of the required quantity using a balance.

6 Reporting the analytical values
6.1 Number of analyses
Analyse the test sample twice on different days.
6.2 Blank test
Upon analysis, perform a blank test to correct the measured values.
6.3 E valuation of the analytical values

When the difference between the two analytical values does not exceed the tolerance value (Table 1),

the average value shall be reported. When the difference between the two analytical values exceeds the

tolerance value, perform two additional analyses. When the difference of these further two analyses

does not exceed the tolerance value, the average value thereof shall be reported. If the difference also

exceeds the tolerance value, the median of four analytical values shall be reported.

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ISO/FDIS 23739:2021(E)
Table 1 — Tolerances for the analytical values
Units: % (mass fraction)
Component Zr Ca, Hf, Mg, Y Al, Ba, Ce, Co, Gd, Fe, K, Na, Si, Sr, Ti
0,01
Tolerance 0,70 0,01
0,1
Applicable to content of less than 0,1 %.
Applicable to content of not less than 0,1 %.
6.4 Expression of analytical values

The analytical values shall be given in % (mass fraction) in dryness. The results shall be expressed to

two decimal places (see Annex A).
7 Decomposition of the test sample
7.1 Classification of the sample decomposition methods
a) Acid pressure decomposition.

b) Alkali fusion, for the determination of the contents of major elements such as zirconium, calcium,

hafnium, magnesium and yttrium, and also for the determination of silicon content.

7.2 Acid pressure decomposition
7.2.1 Reagents

It shall be ascertained that the reagents are of sufficiently high purity to permit their use without

compromising the accuracy of the determination.
7.2.1.1 Water, grade 1 or superior as specified in ISO 3696.
7.2.1.2 Sulfuric acid (1+1).
7.2.2 Apparatus and instruments
Use ordinary laboratory apparatus and instruments together with the following:

7.2.2.1 Pressure decomposition vessel. A pressure decomposition vessel is shown in Figure 1. Use

the vessel exclusively for this analysis to avoid cross-contamination.
7.2.2.2 Polytetrafluoroethylene (PTFE) bottle, with cap.
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ISO/FDIS 23739:2021(E)
7.2.2.3 Air bath, capable of heating at 230 °C ± 5 °C.
Key
1 centre screw
2 screw cap
3 top plate
4 PTFE cap
5 cylinder
6 PTFE bottle
7 bottom plate
Figure 1 — Example of a pressure decomposition vessel
7.2.3 Procedure

Weigh 0,2 g of the test sample in a polytetrafluoroethylene bottle (7.2.2.2) and add 10 ml of sulfuric acid

(1+1). Put the PTFE bottle into a pressure decomposition vessel (7.2.2.1) and close the vessel according

to the manufacturer's instructions. Place the vessel in an air bath and heat it at 230 °C ± 5 °C for 16 h.

After cooling, disassemble the vessel and transfer the dissolved solution to a 150­ml beaker. Wash the

bottle six times with approximately 10 ml of warm water each time and collect the washings into the

beaker. Transfer the solution into a 200-ml volumetric flask, dilute it with water up to the mark and mix

well. This solution is designated as the sample solution.
7.2.4 Blank test

Perform the operation described in 7.2.3 without taking a sample to obtain the blank test value. The

resulting solution is designated as blank test solution.
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ISO/FDIS 23739:2021(E)
7.3 Alkali fusion
7.3.1 Reagents

It shall be ascertained that the reagents are of sufficiently high purity to permit their use without

compromising the accuracy of the determination.
7.3.1.1 Water, grade 1 or superior as specified in ISO 3696.

7.3.1.2 Lithium tetraborate (Li B O ), powdery, more than 99,995 % purity by trace metal basis.

2 4 7

Some commercial products of lithium tetraborate can contain certain impurities such as calcium,

potassium, silicon and sodium. Check their conformity with the test before use.
7.3.1.3 Hydrochloric acid (35 %, mass fraction).
7.3.2 Apparatus and instruments
Use ordinary laboratory apparatus and instruments together with the following:

7.3.2.1 Platinum crucible (30 ml), heated at 1 200 °C ± 50 °C for 15 min, and then cooled down to

room temperature in a desiccator.
7.3.2.2 Platinum lid.
7.3.2.3 Electric furnace, capable of being operated at 1 300 °C.
7.3.2.4 Ultrasonic bath.
7.3.3 Procedure

Mix 0,2 g of the test sample and 1,0 g of lithium tetraborate (7.3.1.2) in a platinum crucible (7.3.2.1).

Add 1,0 g of lithium tetraborate to the mixed sample. After covering the crucible with a platinum lid

(7.3.2.2), place the crucible in an electric furnace (7.3.2.3).

Raise the temperature of the furnace gradually and heat the crucible at 1 200 °C ± 50 °C until the

contents are completely decomposed.
Remove the crucible from the furnace and cool it to room temperature.

Put the crucible and the platinum lid into a 150-ml beaker containing 20 ml of hydrochloric acid (7.3.1.3)

and 100 ml of water (7.3.1.1). Covering the beaker with a watch glass, warm the beaker in an ultrasonic

bath (7.3.2.4) until the melt is completely dissolved into the solution.

Remove the beaker from the ultrasonic bath. Wash the watch glass, the crucible and the platinum lid

several times with approximately 50 ml of water and collect the washings into the beaker. After cooling,

transfer the solution into a 200-ml volumetric flask, dilute it with water up to the mark and mix well.

This is designated as the sample solution.
7.3.4 Blank test

Perform the operation described in 7.3.3 without taking a sample to obtain the blank test value. The

resulting solution is designated as blank test solution.
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ISO/FDIS 23739:2021(E)
8 Determination of the zirconium content
8.1 Precipitation and gravimetric method
8.1.1 Principle

Zirconium with hafnium in the sample solution is precipitated by adding DL-mandelic acid solution.

After igniting the precipitate, the mass of the zirconium oxide (ZrO ) and hafnium oxide (HfO ) is

2 2

measured. The zirconium content is calculated from the mass of zirconium oxide as well as the hafnium

oxide content.
8.1.2 Reagents

It shall be ascertained that the reagents are of sufficiently high purity to permit their use without

compromising the accuracy of the determination.
8.1.2.1 Water, grade 1 or superior as specified in ISO 3696.
8.1.2.2 Hydrochloric acid (35 %, mass fraction).
8.1.2.3 DL-mandelic acid.

8.1.2.4 DL-mandelic acid solution (1 M), dissolve 152,15 g DL­mandelic acid (8.1.2.3) in 1 000 ml of

warm water.

8.1.2.5 Washing solution, dissolve 10 g DL­mandelic acid (8.1.2.3) in 200 ml of warm water and 4 ml

of hydrochloric acid (8.1.2.2).
8.1.3 Apparatus and instruments

Use the apparatus and instruments described in 7.3.2 together with the following:

8.1.3.1 Glass volumetric pipette, 50 ml, Class A, according to ISO 835.
8.1.3.2 Filter paper (ashless), diameter 110 mm, pore size index 8 µm.
8.1.3.3 Hot plate, with magnetic stirrer, capable of being operated at 450 °C.
8.1.4 Procedure

Transfer 50 ml of the sample solution (7.2.3 or 7.3.3) using a volumetric pipette (8.1.3.1) into a 500­ml

beaker. After adding 25 ml of hydrochloric acid (8.1.2.2) to the beaker, heat the solution to 90 °C on a hot

plate. While stirring the solution, add 50 ml of DL­mandelic acid solution (8.1.2.4). Covering the beaker

with a watch glass, heat the beaker at 90 °C for 1h. Wash the watch glass with approximately 30 ml of

warm water and add the washings into the beaker. Filter the solution using a filter paper (8.1.3.2) and

wash the precipitate several times with hot washing solution (8.1.2.5).

Weigh the mass of a platinum crucible (7.3.2.1) to the nearest 0,1 mg. Put the used filter paper and the

precipitate into the crucible and place the crucible in an electric furnace (7.3.2.3). Raise the temperature

of the furnace gradually and ignite the contents at (1 050 ± 50) °C for 30 min.

Remove the crucible from the furnace and cool it in a desiccator. After weighing the mass of the crucible

and the contents to the nearest 0,1 mg, calculate the mass of the precipitate.
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ISO/FDIS 23739:2021(E)
8.1.5 Blank test
Perform the operation described in 8.1.4 with the blank test solu
...

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