SIST EN 61788-5:2014

SLOVENSKI STANDARD
SIST EN 61788-5:2014
01-maj-2014
1DGRPHãþD
SIST EN 61788-5:2002
Superprevodnost - 5. del: Matrika za merjenje superprevodniškega volumenskega
razmerja - Razmerje med bakrom in superprevodniškim volumenskim razmerjem
superprevodnih žic iz kompozita Cu/Nb-Ti (IEC 61788-5:2013)
Superconductivity - Part 5: Matrix to superconductor volume ratio measurement - Copper
to superconductor volume ratio of Cu/Nb-Ti composite superconducting wires
Supraleitfähigkeit - Teil 5: Messung des Verhältnisses von Matrixvolumen zu
Supraleitervolumen - Verhältnis von Kupfervolumen zu Supraleitervolumen von Cu/NbTi-
Verbundsupraleitern
Supraconductivté - Partie 5 : Mesure du rapport volumique matrice/supraconducteur -
Rapport volumique cuivre/supraconducteur des fils en composite supraconducteur
Cu/Nb-Ti
Ta slovenski standard je istoveten z: EN 61788-5:2013
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
SIST EN 61788-5:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61788-5:2014

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SIST EN 61788-5:2014

EUROPEAN STANDARD
EN 61788-5

NORME EUROPÉENNE
September 2013
EUROPÄISCHE NORM

ICS 17.220.20; 29.050 Supersedes EN 61788-5:2001


English version


Superconductivity -
Part 5: Matrix to superconductor volume ratio measurement -
Copper to superconductor volume ratio of Cu/Nb-Ti composite
superconducting wires
(IEC 61788-5:2013)


Supraconductivité -  Supraleitfähigkeit -
Partie 5 : Mesure du rapport volumique Teil 5: Messung des Verhältnisses von
matrice/supraconducteur - Matrixvolumen zu Supraleitervolumen -
Rapport volumique Verhältnis von Kupfervolumen zu
cuivre/supraconducteur des fils en Supraleitervolumen von Cu/Nb-Ti
composite supraconducteur Cu/Nb-Ti Verbundsupraleiterdrähten
(CEI 61788-5:2013) (IEC 61788-5:2013)



This European Standard was approved by CENELEC on 2013-07-02. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61788-5:2013 E

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SIST EN 61788-5:2014
EN 61788-5:2013 - 2 -
Foreword
The text of document 90/321/FDIS, future edition 2 of IEC 61788-5, prepared by IEC/TC 90
"Superconductivity" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN 61788-5:2013.

The following dates are fixed:
(dop) 2014-04-02
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2016-07-02
standards conflicting with the
document have to be withdrawn

This document supersedes EN 61788-5:2001.

EN 61788-5:2013 includes the following significant technical changes with respect to
EN 61788-5:2001:
The main revisions are the addition of two new annexes, "Uncertainty considerations" (Annex E) and
"Uncertainty evaluation in test method of copper to superconductor volume ratio of Cu/Nb-Ti
composite superconductors" (Annex F).

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

Endorsement notice
The text of the International Standard IEC 61788-5:2013 was approved by CENELEC as a European
Standard without any modification.

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SIST EN 61788-5:2014
- 3 - EN 61788-5:2013
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

IEC 60050-815 Series International Electrotechnical Vocabulary - -
(IEV)

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SIST EN 61788-5:2014

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SIST EN 61788-5:2014



IEC 61788-5

®


Edition 2.0 2013-05




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Superconductivity –

Part 5: Matrix to superconductor volume ratio measurement – Copper to

superconductor volume ratio of Cu/Nb-Ti composite superconducting wires




Supraconductivité –

Partie 5: Mesure du rapport volumique matrice/supraconducteur – Rapport


volumique cuivre/supraconducteur des fils en composite supraconducteur

Cu/Nb-Ti












INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX T


ICS 17.220.20; 29.050 ISBN 978-2-83220-831-1



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 61788-5:2014
– 2 – 61788-5 © IEC:2013
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Principle . 7
5 Chemicals . 7
6 Apparatus . 7
7 Measurement procedure . 8
7.1 Quantity of specimen . 8
7.2 Removal of insulating cover material . 8
7.3 Cleaning . 8
7.4 Drying . 8
7.5 Measurement of specimen mass and its repetition . 8
7.6 Dissolving copper . 8
7.7 Cleaning and drying the Nb-Ti filaments . 9
7.8 Measurement of dissolved specimen mass and its repetition . 9
7.9 Procedural repetition for second specimen . 10
8 Calculation of results . 10
9 Uncertainty of the test method . 10
10 Test report . 11
10.1 Identification of test specimen . 11
10.2 Report of copper to superconductor volume ratio . 11
10.3 Report of test conditions . 11
Annex A (normative) Copper to superconductor volume ratio – copper mass method . 12
Annex B (informative) Specific mass depending on Nb-Ti fraction . 14
Annex C (information) Mechanical removal of insulating cover materials . 15
Annex D (informative) Second etch of specimen . 16
Annex E (informative) Uncertainty considerations . 17
Annex F (informative) Uncertainty evaluation in the test method of copper to
superconductor volume ratio of Cu/Nb-Ti composite superconductors . 22

Table B.1 – Specific mass of Nb-Ti . 14
Table E.1 – Output signals from two nominally identical extensometers . 18
Table E.2 – Mean values of two output signals . 18
Table E.3 – Experimental standard deviations of two output signals . 18
Table E.4 – Standard uncertainties of two output signals . 19
Table E.5 – Coefficient of variations of two output signals . 19

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SIST EN 61788-5:2014
61788-5 © IEC:2013 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SUPERCONDUCTIVITY –

Part 5: Matrix to superconductor volume ratio measurement –
Copper to superconductor volume ratio of Cu/Nb-Ti composite
superconducting wires


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in
addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses
arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61788-5 has been prepared by IEC technical committee 90:
Superconductivity.
This second edition cancels and replaces the first edition published in 2000. It constitutes a
technical revision. The main revisions are the addition of two new annexes, "Uncertainty
considerations" (Annex E) and "Uncertainty evaluation in test method of copper to
superconductor volume ratio of Cu/Nb-Ti composite superconductors" (Annex F).
The text of this standard is based on the following documents:
FDIS Report on voting
90/321/FDIS 90/324/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

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SIST EN 61788-5:2014
– 4 – 61788-5 © IEC:2013
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61788 series, published under the general title Superconductivity,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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SIST EN 61788-5:2014
61788-5 © IEC:2013 – 5 –
INTRODUCTION
The copper to superconductor volume ratio of composite superconductors is used mainly to
calculate the critical current density of superconducting wires. The test with the method given
in this International Standard may be used to provide part of the information needed to
determine the suitability of a specific superconductor. Moreover, this method is useful for
quality control, acceptance or research testing if the precautions given in this standard are
observed.
The test method given in this International Standard is based on the condition that the specific
mass of Nb-Ti is known or the Nb-Ti alloy fraction is known and Annex B can be used to estimate
the specific mass. If the specific mass of Nb-Ti is unknown and the Nb-Ti alloy fraction is
unknown and/or the fraction of Nb barrier is unknown, another method to determine the copper
to superconductor volume ratio of composite superconductors is described in Annex A.

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SIST EN 61788-5:2014
– 6 – 61788-5 © IEC:2013
SUPERCONDUCTIVITY –

Part 5: Matrix to superconductor volume ratio measurement –
Copper to superconductor volume ratio of Cu/Nb-Ti composite
superconducting wires



1 Scope
This part of IEC 61788 covers a test method for the determination of copper to superconductor
volume ratio of Cu/Nb-Ti composite superconducting wires.
This test method and the alternate method in Annex A are intended for use with Cu/Nb-Ti
2 2
composite superconducting wires with a cross-sectional area of 0,1 mm to 3 mm , a diameter
of the Nb-Ti filament(s) of 2 µm to 200 µm, and a copper to superconductor volume ratio of 0,5
or more.
The Cu/Nb-Ti composite test conductor discussed in this method has a monolithic structure
with a round or rectangular cross-section. This test method is carried out by dissolving the
copper with nitric acid. Deviations from this test method that are allowed for routine tests and
other specific restrictions are given in this standard.
Cu/Nb-Ti composite superconducting wires beyond the limits in the cross-sectional area, the
filament diameter and the copper to superconductor volume ratio could be measured with this
present method with an anticipated reduction of uncertainty. Other, more specialized,
specimen test geometries may be more appropriate for conductors beyond the limits and have
been omitted from this present standard for simplicity and to retain low uncertainty.
The test method given in this standard is expected to apply to other superconducting composite
wires after some appropriate modifications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
IEC 60050-815 (all parts), International Electrotechnical Vocabulary (available at
)
3 Terms and definitions
For the purposes of this document, the definitions given in IEC 60050-815 as well as the
following definition apply.
3.1
copper to superconductor volume ratio
ratio of the volume of the copper stabilizing material to the volume without copper consisting of
Nb-Ti filaments and their Nb barriers

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SIST EN 61788-5:2014
61788-5 © IEC:2013 – 7 –
4 Principle
The test method utilizes the nature of the Cu/Nb-Ti composite superconducting wire whereby
the copper dissolves in nitric acid solution but the Nb-Ti filaments and Nb barriers do not.
After measuring its mass, dip the specimen into the nitric acid solution to dissolve only the
copper.
Then measure the mass of the remaining Nb-Ti filaments and their Nb barriers.
The volume and mass of the starting wire and the mass of the filaments are used to determine
the copper to superconductor volume ratio.
5 Chemicals
The following chemicals shall be prepared for sample preparation:
a) nitric acid solution consisting of nitric acid (a volume fraction of 50 % to 65 % recommended)
and distilled water;
b) organic solvent;
c) degreasing solvent;
d) ethyl alcohol;
e) distilled (pure) water.
NOTE When nitric acid of more than a mass fraction of 65 % is used, the acid is diluted with distilled water within
the range of the above content.
6 Apparatus
The following apparatus shall be prepared.
• Draft chamber
• Balance
A balance shall have a manufacturer’s specified uncertainty of ±0,1 mg or better.
• Dryer or drying oven
A dryer or a drying oven shall be used for evaporating moisture after washing the specimen.
• Beaker
• Watch-glass
• Plastic tweezers
• Filter papers
• Thermometer
• Rubber gloves and protection spectacles
Rubber gloves and protection spectacles shall be used for protecting the human body from the
harmful acid liquid or fumes. The dissolution of the specimen shall be performed in a draft
chamber in order to protect the human body.

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SIST EN 61788-5:2014
– 8 – 61788-5 © IEC:2013
7 Measurement procedure
7.1 Quantity of specimen
Take a specimen of around 1 g to 10 g in mass from the base test material.
7.2 Removal of insulating cover material
An appropriate organic solvent, which does not erode the copper, shall be used to remove any
insulating cover material of the specimen. Finally, it shall be visually checked that the insulating
cover material no longer remains.
If no organic solvents can remove the insulating cover material, the mechanical removal in
Annex C is an alternative.
7.3 Cleaning
A degreaser shall be used to remove oil and/or grease traces from the specimen, whose cover
material has been removed. It shall then be cleaned with pure water. Finally, the degreased
specimen shall be dipped into ethyl alcohol to replace the water. Cleaning without using ethyl
alcohol is an alternative, by using the drying process described in 7.4.
7.4 Drying
The clean specimen shall be placed on a watch-glass and dried fully in a dryer or a drying oven
at a temperature of 60 °C or lower with the holding time more than 0,5 hours. When cleaning
the specimen is carried out without ethyl alcohol, the specimen shall be dried fully in a dryer or
a drying oven at a temperature of 100 °C with the holding time more than 0,5 hours.
7.5 Measurement of specimen mass and its repetition
When the specimen is cooled down to 35 °C or lower, its mass shall be measured on a sheet of
weighing paper, using a balance with a manufacturer’s specified uncertainty of ±0,1 mg or
better.
After completion of this mass measurement (the first measurement), remove the specimen from
the balance.
To assure that the specimen has been fully dried, the mass of the specimen shall be measured
again about 10 min after the first measurement (the second measurement).
The difference in mass between the first and second measurements shall be within ±0,5 %. If
this difference is within ±0,5 %, the average of the two measurements shall be regarded as the
mass of the specimen.
If the difference in mass is more than ±0,5 %, cleaning of the specimen with ethyl alcohol and
drying of the specimen shall be repeated as described in 7.3, 7.4 and 7.5 until the difference in
mass of the two measurements is within ±0,5 %.
As soon as this part of the method is qualified by a successful repetition, the second mass
measurement can be omitted in subsequent measurements. However, periodic re-qualification
shall be performed every six months or after changes of equipment or personnel.
7.6 Dissolving copper
The copper shall be dissolved from the specimen in the following manner.

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SIST EN 61788-5:2014
61788-5 © IEC:2013 – 9 –
Put approximately 150 ml of the nitric acid solution in a 300 ml beaker. Tie a knot in the
specimen to help retain all of the filaments upon completion of the etch. In the draft chamber,
while maintaining the temperature of the nitric acid solution between 20 °C and 50 °C, the
whole specimen shall be dipped into the nitric acid solution for 30 min to 1 h to completely
dissolve the copper of the specimen. It shall be checked visually that the copper has been
completely dissolved. For wires with filaments less than 10 µm, the second etch according to
Annex D is recommended to assure a complete copper dissolution.
Note that a fresh nitric acid solution shall be used for each specimen that is etched.
When copper is dissolved in the nitric acid solution, nitrite gas is generated. Because the nitric
acid and the nitrite gas are harmful to the human body, use all safety precautions in handling
acids such as wearing protective clothing and carrying out work to dissolve the copper in the
draft chamber. In addition, the fumes generated during storage and use are harmful. Normal
safety precautions for acid storage, use and disposal shall be followed.
Use rubber gloves, protection spectacles and a pair of plastic tweezers during the treatment of
the nitric acid solution.
NOTE The temperature of the nitric acid solution specified here is that before dipping the specimen in it. The
temperature can rise to more than 50 °C when dissolution of the copper is in progress.
When mixing the solution, always add the nitric acid to the water.
7.7 Cleaning and drying the Nb-Ti filaments
Cleaning and drying the Nb-Ti filaments shall be performed in the following manner.
Acid shall be carefully poured out of the beaker into a plastic sewage reservoir, keeping the
specimen in the beaker so as not to lose any broken filaments. The beaker shall be refilled with
distilled water to rinse. The water shall be carefully poured out of the beaker. The beaker shall
now be refilled, with ethyl alcohol this time to replace any remaining water. Now to dry all of the
filaments fully, the specimen shall be placed, using plastic tweezers, on a sheet of filter paper
with any broken or loose filaments. They shall then be placed in a dryer or a drying oven
(see 7.4).
If a green stain is noticed on the filter paper, then there is acid remaining on the filaments. This
acid shall be removed by rinsing again in alcohol.
Cleaning without using ethyl alcohol is an alternative, by using the drying process described
in 7.4.
If there are too many broken filaments, the procedures shall be repeated from the beginning on
a new specimen.
Nb-Ti filaments with a diameter of about 10 µm or less can be combustible when they are
removed from the acid and exposed to air after the matrix has been removed. Ignition sources
(including flame, heat, spark and electrostatic discharge) are avoided. In addition, tweezers
shall be used to handle the etched filaments and they shall not be put in contact with any part of
the body. Normal safety precautions for metal combustion hazards shall be followed.
7.8 Measurement of dissolved specimen mass and its repetition
When the specimen is cooled down to 35 °C or lower, using a balance with a manufacturer’s
specified uncertainty of ±0,1 mg or better, the specimen shall be weighed as in 7.5. A sheet of
weighing paper shall be used for the measurement to avoid losing broken filaments (the first
measurement).

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SIST EN 61788-5:2014
– 10 – 61788-5 © IEC:2013
After completion of the mass measurement described in 7.5, the Nb-Ti filaments shall be
removed from the balance. To know whether the Nb-Ti filaments have been fully dried, the
mass of the Nb-Ti filaments shall be weighed again about 10 min after the first measurement
(the second measurement).
The difference in mass shall be within ±0,5 % between the second measurement and the first
measurement. If the difference in mass is within ±0,5 % between the two measurements, the
average of the masses of the two measurements shall be regarded as the mass of the
filaments.
If the difference in mass of the two measurements is more than ±0,5 %, only cleaning with ethyl
alcohol and drying shall be repeated as described in the procedural step of 7.7, and then
procedural steps shall be repeated again in the procedural step of 7.5. Then, check again to
make sure that the difference in mass of the two measurements is within ±0,5 %.
As soon as this part of the method is qualified by a successful repetition, the second mass
measurement can be omitted in subsequent measurements. However, periodic re-qualification
shall be performed every six months or after changes in equipment or personnel.
7.9 Procedural repetition for second specimen
The procedural steps in 7.1 through 7.8 shall be repeated on the second specimen.
As soon as the method is qualified by a successful repetition, the repeated measurements on
the second specimen can be omitted in subsequent measurements. However, periodic
re-qualification shall be performed every six months or after changes in equipment or
personnel.
8 Calculation of results
For each measurement, the copper to superconductor volume ratio shall be obtained down to
two decimal places in the following equation, by rounding
...