ISO 9350:2025

Corrosion of metals and alloys — Testing method of corrosion resistance for hafnium at high temperature and pressure

This document specifies: a) the determination of mass gain; b) the surface inspection of products of hafnium when corrosion tested in water at 360 °C. This document is applicable to hot-work or cold-work hafnium rods, wires, plates, sheets and strips. This method has been widely used in the development of hafnium products. It is applicable for use in its entirety to the extent specified for a product acceptance test, rather than merely a means of assessing performance in service of pressurized water reactor.

Corrosion des métaux et alliages — Méthode d'essai de la résistance à la corrosion du hafnium à haute température et pression

General Information

• Status: Published
• Publication Date: 27-Aug-2025
• ICS: 77.060 - Corrosion of metals
• Technical Committee: ISO/TC 156 - Corrosion of metals and alloys
• Drafting Committee: ISO/TC 156 - Corrosion of metals and alloys
• Current Stage: 6060 - International Standard published
• Start Date: 28-Aug-2025
• Due Date: 10-Oct-2025
• Completion Date: 28-Aug-2025

Standards Content (Sample)

International
Standard
ISO 9350
First edition
Corrosion of metals and alloys —
2025-08
Testing method of corrosion
resistance for hafnium at high
temperature and pressure
Corrosion des métaux et alliages — Méthode d'essai de la
résistance à la corrosion du hafnium à haute température et
pression
Reference number
© ISO 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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Significance . 2
6 Reagents and materials . 2
7 Apparatus . 2
8 Hazards . 3
9 Sampling, test specimens and test units . 3
10 Preparation of apparatus . 3
11 Calibration and standardization . 3
11.1 Coupon preparation .3
11.2 Autoclaves .4
11.3 Use of control coupons.4
11.4 Calibration .5
12 Conditioning . 5
12.1 Test water quality .5
12.2 Autoclave load restrictions .5
12.3 Test conditions .5
12.3.1 Temperature .5
12.3.2 Pressure .5
12.3.3 Time .5
12.3.4 Tests .5
12.4 Specimen preparation .6
12.4.1 Etched specimens .6
12.4.2 As-manufacturer specimens .6
13 Procedure . 6
13.1 Inspection of specimens . .6
13.2 Dimensions, weight and inspection .6
13.3 Autoclaving .6
13.3.1 Placing of test specimens .6
13.3.2 Venting method A .6
13.3.3 Refreshed autoclaving, method B .7
13.4 Post-test measurements and inspection .7
14 Calculation or interpretation of results . 7
14.1 Calculation of mass gain .7
14.2 Visual interpretation of surface appearance .8
14.3 Invalid tests .8
15 Test report . 8
Annex A (informative) Guide to specimen preparation . 9
Bibliography .11

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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 156, Corrosion of metals and alloys.
Any feedback or questions on this document are directed to the user’s national standards body. A complete
listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Hafnium has a high-capture cross section for thermal energy. It is used in nuclear reactors. Hafnium is
typically manufactured into rods, plates, sheets and strips. It is used as a neutron absorption material.
This document establishes a test method for the corrosion of hafnium. The water corrosion test is a useful
way to evaluate the properties of hafnium. The corrosion test can determine the performance of hafnium
products in reactors. The parameters of the corrosion test are different to the parameters of tests for other
materials. This is why a test method for the corrosion of hafnium is necessary.
This document establishes a corrosion test and requirements for hafnium material and provides a basis for
consistency across different laboratories. This document also gives the performance prediction of hafnium
products in service.
v
International Standard ISO 9350:2025(en)
Corrosion of metals and alloys — Testing method of corrosion
resistance for hafnium at high temperature and pressure
WARNING — The use of this document can involve hazardous materials, operations and equipment
(see Clause 8). It is the responsibility of the user of this document to consult and establish appropriate
safety and health practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This document specifies:
a) the determination of mass gain;
b) the surface inspection of products of hafnium when corrosion tested in water at 360 °C.
This document is applicable to hot-work or cold-work hafnium rods, wires, plates, sheets and strips.
This method has been widely used in the development of hafnium products. It is applicable for use in its
entirety to the extent specified for a product acceptance test, rather than merely a means of assessing
performance in service of pressurized water reactor.
2 Normative references
T
...

FINAL DRAFT
International
Standard
ISO/FDIS 9350
ISO/TC 156
Corrosion of metals and alloys —
Secretariat: SAC
Testing method of corrosion
Voting begins on:
resistance for hafnium at high
2025-05-22
temperature and pressure
Voting terminates on:
2025-07-17
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
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
ISO/FDIS 9350:2025(en) © ISO 2025

FINAL DRAFT
ISO/FDIS 9350:2025(en)
International
Standard
ISO/FDIS 9350
ISO/TC 156
Corrosion of metals and alloys —
Secretariat: SAC
Testing method of corrosion
Voting begins on:
resistance for hafnium at high
temperature and pressure
Voting terminates on:
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.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 9350:2025(en) © ISO 2025

ii
ISO/FDIS 9350:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Significance . 2
6 Reagents and materials . 2
7 Apparatus . 2
8 Hazards . 3
9 Sampling, test specimens and test units . 3
10 Preparation of apparatus . 3
11 Calibration and standardization . 3
11.1 Coupon preparation .3
11.2 Autoclaves .4
11.3 Use of control coupons.4
11.4 Calibration .5
12 Conditioning . 5
12.1 Test water quality .5
12.2 Autoclave load restrictions .5
12.3 Test conditions .5
12.3.1 Temperature .5
12.3.2 Pressure .5
12.3.3 Time .5
12.3.4 Tests .5
12.4 Specimen preparation .6
12.4.1 Etched specimens .6
12.4.2 As-manufacturer specimens .6
13 Procedure . 6
13.1 Inspection of specimens . .6
13.2 Dimensions, weight and inspection .6
13.3 Autoclaving .6
13.3.1 Placing of test specimens .6
13.3.2 Venting method A .6
13.3.3 Refreshed autoclaving, method B .7
13.4 Post-test measurements and inspection .7
14 Calculation or interpretation of results . 8
14.1 Calculation of mass gain .8
14.2 Visual interpretation of surface appearance .8
14.3 Invalid tests .8
15 Test report . 8
Annex A (informative) Guide to specimen preparation . 9
Bibliography .11

iii
ISO/FDIS 9350:2025(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 156, Corrosion of metals and alloys.
Any feedback or questions on this document are directed to the user’s national standards body. A complete
listing of these bodies can be found at www.iso.org/members.html.

iv
ISO/FDIS 9350:2025(en)
Introduction
Hafnium has a high-capture cross section for thermal energy. It is used in nuclear reactors. Hafnium is
typically manufactured into rods, plates, sheets and strips. It is used as a neutron absorption material.
This document establishes a test method for the corrosion of hafnium. The water corrosion test is a useful
way to evaluate the properties of hafnium. The corrosion test can determine the performance of hafnium
products in reactors. The parameters of the corrosion test are different to the parameters of tests for other
materials. This is why a test method for the corrosion of hafnium is necessary.
This document establishes a corrosion test and requirements for hafnium material and provides a basis
...

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ISO/TC 156
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Secretariat: SAC
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Date: 2025-05-07
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Corrosion of metals and alloys — Testing method of corrosion
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resistance for hafnium at high temperature and pressure
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ISO/DISFDIS 9350:2025(en)
Formatted: Font: 11 pt
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Formatted: Font: 11 pt
Formatted: HeaderCentered, Space After: 0 pt, Line
spacing: single
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
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
Formatted: FooterPageRomanNumber
2 © ISO 2020 – All rights reserved
ii
ISO/FDIS 9350:2025(en)
Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold, English (United Kingdom)
Formatted: Font: 11 pt, Bold
Contents
Formatted: Font: Bold
Formatted: HeaderCentered, Left
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Significance . 2
6 Reagents and materials . 2
7 Apparatus . 2
8 Hazards . 3
9 Sampling, test specimens and test units . 3
10 Preparation of apparatus . 3
11 Calibration and standardization . 3
11.1 Coupon preparation . 3
11.2 Autoclaves . 4
11.3 Use of control coupons . 4
11.4 Calibration . 5
12 Conditioning . 5
12.1 Test water quality . 5
12.2 Autoclave load restrictions . 5
12.3 Test conditions . 5
12.4 Specimen preparation . 6
13 Procedure . 6
13.1 Inspection of specimens . 6
13.2 Dimensions, weight and inspection . 6
13.3 Autoclaving . 6
13.4 Post-test measurements and inspection . 7
14 Calculation or interpretation of results . 7
14.1 Calculation of mass gain . 7
14.2 Visual interpretation of surface appearance . 8
14.3 Invalid tests . 8
15 Test report . 8
Annex A (informative) Guide to specimen preparation . 9
Bibliography . 11

Formatted: Font: 10 pt
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Formatted: FooterCentered, Left, Line spacing: single
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iii
ISO/DISFDIS 9350:2025(en)
Formatted: Font: 11 pt
Formatted: Font: 11 pt
Formatted: Font: 11 pt
Foreword
Formatted: HeaderCentered, Space After: 0 pt, Line
spacing: single
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 156, Corrosion of metals and alloys.
Any feedback or questions on this document are directed to the user’s national standards body. A complete
listing of these bodies can be found at www.iso.org/members.html.
Formatted: FooterPageRomanNumber
4 © ISO 2020 – All rights reserved
iv
ISO/FDIS 9350:2025(en)
Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold, English (United Kingdom)
Formatted: Font: 11 pt, Bold
Introduction
Formatted: Font: Bold
Formatted: HeaderCentered, Left
Hafnium has a high-capture cross section for thermal energy. It is used in nuclear reactors. Hafnium is typically
manufactured into rods, plates, sheets and strips. It is used as a neutron absorption material.
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
This document establishes a test method for the corrosion of hafnium. The water corrosion test is a useful way
to evaluate the properties of hafnium. The corrosion test can determine the performance of hafnium products
in reactors. The parameters of the corrosion test are different to the parameters of tests for other materials.
This is why a test method for the corrosion of hafnium is necessary.
This document establishes a corrosion test and requirements for hafnium material, and provides a basis for
consistency across different laboratories. This document also gives the performance prediction of hafnium
products in service.
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: FooterCentered, Left, Line spacing: single
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Left, Space
After: 0 pt, Line spacing: single
v
FINAL DRAFT International Standard ISO/FDIS 9350

Corrosion of metals and alloys — Testing method of corrosion
resistance for hafnium at high temperature and pressure
WARNING — The use of this document can involve hazardous materials, operations and equipment
(see 8). It is the responsibility of the user of this document to consult and establish appropriate safety
and health practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This document specifies:
a) the determination of mass gain;
b) the surface inspection of products of hafnium when corrosion tested in water at 360 °C.
This document is applicable to hot-work or cold-work hafnium rods, wires, plates, sheets and strips.
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
This method has been widely used in the development of hafnium products. It is applicable for use in its
entirety to the extent specified for a product acceptance test, rather than merely a means of assessing
performance in service of pressurized water reactor.
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 https://www.electropedia.org/
3.1
etching
process to remove surface metal by action of acids in water
3.2
control coupon
hafnium specimen of known performance used to monitor the validity of the test
4 Principle
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
Specimens of hafnium are exposed to high-pressure water at 360 °C for 672 h. The corrosion is normally
measured by the gain in mass of the specimens and inspected by the appearance of an oxide film on the
specimen surfaces. The test pressure in water is 18,7 MPa. The pressure is also determined by the contractor
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requirements.
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ISO/DISFDIS 9350:2025(en)
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5 Significance
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Specimens are normally tes
...