1、 INTERNATIONAL STANDARD IEC 61788-3Second edition 2006-04Superconductivity Part 3: Critical current measurement DC critical current of Ag- and/or Ag alloy-sheathed Bi-2212 and Bi-2223 oxide superconductors Reference number IEC 61788-3:2006(E) Publication numbering As from 1 January 1997 all IEC publ
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8、ONAL STANDARD IEC 61788-3Second edition 2006-04Superconductivity Part 3: Critical current measurement DC critical current of Ag- and/or Ag alloy-sheathed Bi-2212 and Bi-2223 oxide superconductors IEC 2006 Copyright - all rights reserved No part of this publication may be reproduced or utilized in an
9、y form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission, 3, rue de Varemb, PO Box 131, CH-1211 Geneva 20, Switzerland Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-ma
10、il: inmailiec.ch Web: www.iec.ch T For price, see current catalogue PRICE CODE Commission Electrotechnique Internationale International Electrotechnical Commission 2 61788-3 IEC:2006(E) CONTENTS FOREWORD.3 INTRODUCTION.5 1 Scope.6 2 Normative reference.6 3 Terms and definitions .6 4 Principle.8 5 Re
11、quirements.8 6 Apparatus.8 7 Specimen preparation.9 8 Measurement procedure.10 9 Precision and accuracy of the test method11 10 Calculation of results12 11 Test report13 Annex A (informative) Additional information relating to Clauses 1 to 1015 Annex B (informative) Magnetic hysteresis of the critic
12、al current of high-temperature oxide superconductors21 Bibliography23 Figure 1 Intrinsic U-I characteristic 14 Figure 2 U-I characteristic with a current transfer component.14 Figure A.1 Illustration of a measurement configuration for a short specimen of a few hundred A class conductors20 Figure A.2
13、 Illustration of superconductor simulator circuit 20 Table A.1 Thermal expansion data of Bi-oxide superconductor and selected materials 19 61788-3 IEC:2006(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ SUPERCONDUCTIVITY Part 3: Critical current measurement DC critical current of Ag- and/or Ag all
14、oy-sheathed Bi-2212 and Bi-2223 oxide superconductors 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-operat
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23、r 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 m
24、ay be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61788-3 has been prepared by IEC technical committee 90: Superconductivity. This second edition cancels and replaces the first edition published in 2000. Mo
25、difications made to the second version mostly involve wording and essentially include no technical changes. Examples of technical changes introduced include the voltage lead diameter being smaller than 0,21 mm and the mode of expression for magnetic field accuracy being 1 % and 0,02 T instead of 1 %
26、 The expression for magnetic field precision has been changed in the same way. The text of this standard is based on the following documents: FDIS Report on voting 90/184/FDIS 90/190/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated
27、in the above table. 4 61788-3 IEC:2006(E) This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. IEC 61788 consists of the following parts, under the general title Superconductivity: Part 1: Critical current measurement DC critical current of Cu/Nb-Ti composite super- c
28、onductors Part 2: Critical current measurement DC critical current of Nb 3 Sn composite super- conductors Part 3: Critical current measurement DC critical current of Ag- and/or Ag alloy-sheathed Bi-2212 and Bi-2223 oxide superconductors Part 4: Residual resistance ratio measurement Residual resistan
29、ce ratio of Nb-Ti composite superconductors Part 5: Matrix to superconductor volume ratio measurement Copper to superconductor volume ratio of Cu/Nb-Ti composite superconductors Part 6: Mechanical properties measurement Room temperature tensile test of Cu/Nb-Ti composite superconductors Part 7: Elec
30、tronic characteristic measurements Surface resistance of superconductors at microwave frequencies Part 8: AC loss measurements Total AC loss measurement of Cu/Nb-Ti composite superconducting wires exposed to a transverse alternating magnetic field by a pickup coil method Part 9: Measurements for bul
31、k high temperature superconductors Trapped flux density of large grain oxide superconductors Part 10: Critical temperature measurement Critical temperature of Nb-Ti, Nb 3 Sn, and Bi-system oxide composite superconductors by a resistance method Part 11: Residual resistance ratio measurement Residual
32、resistance ratio of Nb 3 Sn composite superconductors Part 12: Matrix to superconductor volume ratio measurement Copper to non-copper volume ratio of Nb 3 Sn composite superconducting wires Part 13: AC loss measurements Magnetometer methods for hysteresis loss in Cu/Nb-Ti multifilamentary composites
33、 The committee has decided that the contents of this publication will remain unchanged until the maintenance result 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
34、 by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. 61788-3 IEC:2006(E) 5 INTRODUCTION In 1986 J.G. Bednorz and K.A. Mueller discovered that some Perovskite type Cu-containing oxides show superconductivity at temperatures far above those which me
35、tallic superconductors have shown. Since then, extensive R & D work on high-temperature oxide superconductors has been and is being made worldwide, and its application to high-field magnet machines, low-loss power transmission, electronics and many other technologies is in progress 1. 1)Fabrication
36、technology is essential to the application of high-temperature oxide super- conductors. Among high-temperature oxide superconductors developed so far, BiSrCaCu oxide (Bi-2212 and Bi-2223) superconductors have been the most successful at being fabricated into wires and tapes of practical length and s
37、uperconducting properties. These conductors can be wound into a magnet to generate a magnetic field of several tesla 2. It has also been shown that Bi-2212 and Bi-2223 conductors can substantially raise the limit of magnetic field generation by a superconducting magnet 3. In summer 1993, VAMAS-TWA16
38、 started working on the test methods of critical currents in Bi-oxide superconductors. In September 1997, the TWA16 worked out a guideline (VAMAS guideline) on the critical current measurement method for Ag-sheathed Bi-2212 and Bi-2223 oxide superconductors. This pre-standardization work of VAMAS wa
39、s taken as the base for the IEC standard, described in the present document, on the dc critical current test method of Ag-sheathed Bi-2212 and Bi-2223 oxide superconductors. The test method covered in this International Standard is intended to give an appropriate and agreeable technical base to thos
40、e engineers working in the field of superconductivity technology. The critical current of composite superconductors like Ag-sheathed Bi-oxide superconductors depends on many variables. These variables need to be considered in both the testing and the application of these materials. Test conditions s
41、uch as magnetic field, temperature and relative orientation of the specimen and magnetic field are determined by the particular application. The test configuration may be determined by the particular conductor through certain tolerances. The specific critical current criterion may be determined by t
42、he particular application. It may be appropriate to measure a number of test specimens if there are irregularities in testing. 1)The numbers in brackets refer to the bibliography. 6 61788-3 IEC:2006(E) SUPERCONDUCTIVITY Part 3: Critical current measurement DC critical current of Ag- and/or Ag alloy-
43、sheathed Bi-2212 and Bi-2223 oxide superconductors 1 Scope This part of IEC 61788 covers a test method for the determination of the dc critical current of short and straight Ag- and/or Ag alloy-sheathed Bi-2212 and Bi-2223 oxide superconductors that have a monolithic structure and a shape of round w
44、ire or flat or square tape containing mono- or multicores of oxides. This method is intended for use with superconductors that have critical currents less than 500 A and n-values larger than 5. The test is carried out with and without an applying external magnetic field. For all tests in a magnetic
45、field, the magnetic field is perpendicular to the length of the specimen. In the test of a tape specimen in a magnetic field, the magnetic field is parallel or perpendicular to the wider tape surface (or one surface if square). The test specimen is immersed either in a liquid helium bath or a liquid
46、 nitrogen bath during testing. Deviations from this test method that are allowed for routine tests and other specific restrictions are given in this standard. 2 Normative reference The following referenced document is indispensable for the application of this document. For dated references, only the
47、 edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60050-815:2000, International Electrotechnical Vocabulary (IEV) Part 815: Super- conductivity 3 Terms and definitions For the purposes of this document, the terms and
48、 definitions given in IEC 60050-815, several of which have been repeated her for convenience, and the following apply. 3.1 critical current I cmaximum direct current that can be regarded as flowing without resistance NOTE I cis a function of magnetic field strength and temperature. IEV 815-03-01 3.2
49、 critical current criterion I ccriterion criterion to determine the critical current, I c , based on the electric field strength, E or the resistivity, NOTE 1 E = 10 V/m or E = 100 V/m is often used as the electric field strength criterion, and = 10 -13 m or = 10 -14 m is often used as the resistivity criterion. 61788-3 IEC:2006(E) 7 NOTE 2 For short high temperature oxide supercondu
