GB/T 45982.1-2025Micro joining of 2nd generation high temperature superconductors - Part 1: General requirements for the procedure (English PDF)

Foreword

This document is in accordance with the rules of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

This document is Part 1 of GB/T 45982 "Micro-connections of the second generation of high temperature superconductors".

MicroConnect has published the following sections.

--- Part 1: Process requirements;

--- Part 2: Qualification of welding and testing personnel;

--- Part 3: Test methods for joints.

This document is modified to adopt ISO 17279-1:2018 "Welding of second-generation high-temperature superconductors — Microjoints — Part 1: General process requirements".

This document has the following structural adjustments compared to ISO 17279-1:2018.

a) 3.2 corresponds to 3.3 in ISO 17279-1:2018;

b) 3.3 corresponds to 3.5 in ISO 17279-1:2018;

c) 3.5 corresponds to 3.7 in ISO 17279-1:2018;

d) 5.5.4.9 corresponds to 5.5.4.10 in ISO 17279-1:2018;

e) 5.5.4.10 corresponds to 5.5.4.11 in ISO 17279-1:2018.

The technical differences between this document and ISO 17279-1:2018 and their reasons are as follows.

a) deleted the contents that are not within the scope of this document (see Chapter 1 of ISO 17279-1:2018);

b) Added the definition documents GB/T 2900.100 and GB/T 3375 (see Chapter 3) to facilitate the use of this document.

application;

c) Added the normative reference document GB/T 19866 (see Chapter 3), deleted ISO/T R25901 (all parts) (see Chapter 3 of ISO 17279-1:2018) replaces ISO 17279-2 (see 5.5.1, 5.5.3.1 and 5.5.4.1), the normative reference document GB/T 45982.3 replaces ISO 17279-3 (see 5.4.1, 5.5.4.1 and 5.7) to suit my country's technical conditions;

d) The terms and definitions "low-temperature superconductor", "pressurized partial micro-melting diffusion" and "pressurized solid-state diffusion" have been deleted (see ISO 17279-1:2018 3.2, 3.4, and 3.6);

e) Added the term and definition of "lap joint" (see 3.4), deleted the normative reference ISO 15607:2003 (see 2 of ISO 17279-1:2018) and Table 1 of ISO 15607:2003 (see ISO 17279-1:2018, Clause 2) and the symbols and abbreviations in Table 1 of ISO 15607:2003

2018), to facilitate the application of this document;

f) Added explanations of 6 symbols (see Chapter 4) to facilitate the application of this document;

g) Added some parameters that need to be set in the micro-connection and oxidation annealing processes [see 5.5.3.2c) and 5.5.3.4c)], which are implemented Essential test parameters in the process to improve the operability of the process;

h) A sampling step after the oxidation annealing process is added [see 5.5.3.3i)] to improve the operability of the process and eliminate ambiguity;

i) Deleted the verification and acceptance criteria for the joint Jc in the four-lead method test (see 5.5.4.2, 5.5.4.4 and 5.5.5.6 of ISO 17279-1:2018)

Table 5 in 5.9) to apply my country's technical conditions;

j) Deleted the critical magnetic field test requirements and the acceptance criteria for joints using the critical magnetic field test (see ISO 17279-1:2018

Table 10 in 5.5.4.2, 5.5.4.9 and 5.9);

k) Scanning electron microscopy, transmission electron microscopy and X-ray diffraction tests (see ISO 17279-1:2018) have been deleted.

5.5.4.2 and 5.5.4.11) to apply my country's technical conditions;

l) Deleted the acceptance criteria for the four-lead method test in the manufacture of nuclear magnetic resonance or magnetic resonance imaging magnets (see ISO 17279.1.

(Table 5 in 5.9 of 2018).

m) The acceptance criteria for joint resistance in the magnetic field attenuation test (see Table 6 in 5.9) have been changed to suit my country's technical requirements;

n) The acceptance criteria for the bending test (see Table 9 in 5.9) have been changed to suit my country's technical requirements.

The following editorial changes have been made to this document.

a) To coordinate with the existing standard, the name of the standard is changed to "Second Generation High-Temperature Superconductor Microconnection Part 1: Process Requirements";

b) Added some figure legends (see Figure 4, Figure 5, Figure 8, Figure B.1, Figure B.2, Figure C.1, Figure C.2, Figure D.1, Figure D.2);

c) Changed the index numbers of the micro-joining and oxidation annealing process curves (see 5.4.1, Appendix B, Appendix C, Appendix D);

d) Changed the oxidation annealing process step sequence number (see 5.5.3.3);

e) Added introductory words and titles to the tables (see Tables A.1 to A.3 in Appendix A and Tables E.1 to E.3 in Appendix E);

f) Added some parameters required in the process checklist (see Table A.1 and Table A.3 in Appendix A);

g) Added the sampling step in the oxidation annealing process checklist (see Table A.2 in Appendix A);

h) Deleted the sampling steps in the micro-joining and oxidation annealing process checklist (see Table A.3 in Appendix A), and changed some inspection steps.

Steps (see Table A.3 in Appendix A);

i) Deleted some notes (see 5.2, 5.5.3.3, 5.5.3.4, Annex B, Annex C and Annex D of ISO 17279-1:2018);

j) Deleted the redundant statements in this section (see 5.2 and 5.3 of ISO 17279-1:2018);

k) Deleted some explanatory descriptive content (see 5.4.1, 5.5.2, 5.5.3.2, 5.5.3.4, 5.5.4.4,

Table A.1 and Table A.3 in Appendix A);

l) The test results of the critical magnetic field test and X-ray diffraction test have been deleted (see Annex C of ISO 17279-1:2018).

Introduction

With the widespread application of the second generation of high temperature superconductors (2GHTS) and the invention of 2GHTS resistance-free connection technology, it is necessary to formulate this document ensures that 2GHTS are connected in the most efficient way and that all implementation processes are properly controlled.

In order to ensure the quality of 2GHTS joints, it is necessary to formulate national standards for micro-joining process and joint evaluation specifications.

"Conductor Microconnection" is a universal management standard for microconnections of second-generation high-temperature superconductors, and is intended to consist of three parts.

--- Part 1: Process requirements;

--- Part 2: Qualification of welding and testing personnel;

--- Part 3: Test methods for joints.

Superconducting materials have zero resistance conduction and complete anti-magnetism below the critical temperature T, critical magnetic field strength Bc and critical current density Jc.

Once activated, current will flow forever in the diamagnetic closed loop of the superconducting material.

2GHTS consists of multiple layers with a total thickness of about 60µm~100µm, with or without copper stabilization layer coating.

The thickness of the superconducting layer prepared by (REBCO) is only 1µm~3µm, depending on the specifications of 2GHTS. Re represents rare earth materials, including

Figure 1 is a schematic diagram of the multilayer structure of a typical 2GHTS, and indicates the composition of each layer including the copper stabilization layer.

The two copper stabilization layers numbered 1 in FIG1 do not exist in the 2GHTS without stabilization layer.

Index number description.

1---20µm thick copper stabilization layer;

2---2µm thick silver protective layer;

3---1µm~3µm thick REBCO superconducting layer;

4-5 buffer layers (total thickness 160nm);

5-50µm thick Hastelloy alloy substrate.

Note. Not drawn to scale.

Figure 1 Schematic diagram of the multilayer structure of a typical 2GHTS

At present, the superconducting industry uses soft soldering (see Figure 2), brazing or other filling materials to connect joints.

High resistance at the head can create fatal defects in the superconductor.

a) Lap joint b) Bridge joint Index number description.

1---superconducting layer;

2---Soft solder.

Figure 2 Schematic diagram of 2GHTS soldering connection joint

This paper focuses on the direct self-bonding of 1 µm to 3 µm thick 2GHTS superconducting layers without the use of filler materials (see

3), and the superconducting properties were restored through oxidation annealing process, and the resistance at the joint was almost zero.

a) Lap joint b) Bridge joint Index number description.

1---Superconducting layer.

Figure 3 Schematic diagram of the direct self-connection joint between two superconducting layers of 2GHTS

It is necessary to develop a welding procedure specification (WPS) to provide a basis for quality control of micro-joining operations and micro-joining processes.

In the quality system terminology standards, micro joining is considered a special process. Usually, the quality system standards require special processes.

Therefore, before actual production, a set of rules for micro-joining process evaluation should be established to ensure that the published WPS meets the requirements.

This document, as a universal standard for micro-connections of second-generation high-temperature superconductors, specifies general requirements for related processes, third-party inspections, and welding procedures.

The content of the welding process specification (WPS) and its assessment is conducive to the national standardization of the second generation high temperature superconductor micro-joining process requirements.

The relevant regulations and guidance for the specific implementation of the second generation high temperature superconductor micro-connection work will also provide a reference for the second generation high temperature superconductor micro-connection technology in China.

Provide standard support for the promotion and application in China.

Second generation high temperature superconductor microconnection Part 1: Process requirements

1 Scope

This document specifies the process requirements and third-party inspection for micro-connections of second-generation high-temperature superconductors.

This document applies to micro-connections of second-generation high-temperature superconductors, but does not include soldering, brazing or filler material connections.

The connection between bismuth-substituted strontium calcium copper oxide (1GB SCCO) type high-temperature superconductors and low-temperature superconductors (LTS).

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 2900.100 Electrical terminology - Superconductivity GB/T 3375 Welding terminology GB/T 19866 Welding procedure specifications and general principles for their qualification (GB/T 19866-2005, ISO 15607:2003, IDT) GB/T 45982.2 Microjoining of second generation high temperature superconductors Part 2: Qualification of welding and testing personnel (GB/T 45982.2-2025, ISO 17279-2:2018, MOD)

3 Terms and Definitions

The terms and definitions defined in GB/T 2900.100, GB/T 3375, GB/T 19866 and the following apply to this document.

Usually refers to a superconductor with a critical temperature above 25K.

[Source. GB/T 2900.100-2017, 815-11-11] 3.2 A tape superconductor with a critical temperature above 25K, made of rare earth and other elements such as barium, copper and their oxides.

Note. First generation high temperature superconductors (1GHTS) are superconductors with a critical temperature above 25K and are made of bismuth strontium calcium copper oxide.

Oxidation annealing

Process to re-establish oxygen stoichiometry and restore superconducting properties in an oxygen-rich environment.

Note. Because the structure and superconducting properties of 2GHTS are deeply affected by the oxygen stoichiometry, the 2GHTS joint induces oxygen to diffuse outward at high temperature, resulting in its Phase transition from superconducting orthorhombic phase to non-superconducting tetragonal phase.

lap joint

A joint formed by micro-connecting the upper and lower parts of two 2GHTS superconductors.

Note. See Figure 3a) and Figure 4.