GB/T 25897-2020Residual resistance ratio measurement. Residual resistance ratio of Nb-Ti and Nb[3]Sn composite superconductors (English PDF)

1 Scope

This standard specifies the copper (Cu), copper-nickel (Cu-Ni), copper/copper-nickel (Cu/Cu-Ni) matrix and aluminum under the condition of no strain and no applied magnetic field:

(Al) Test method for residual resistance ratio (RRR) of niobium-titanium (Nb-Ti) and niobium-three-tin (Nb3Sn) composite superconductors in the matrix: This standard applies to

The residual resistance ratio is less than 350, the cross section is less than 3mm2, and the residual resistance ratio of the integrated superconductor with rectangular or circular cross section is measured:

the amount: For the Nb3Sn composite superconductor, the sample undergoes reaction heat treatment:

2 Normative references

The following documents are indispensable for the application of this document: For dated reference documents, only the dated version applies to this article

Pieces: For undated references, the latest version (including all amendments) applies to this document:

IEC 60050-815 International Electrotechnical Term (IEV) Part 815: Superconductivity (InternationalElectrotechnicalVo- cabulary-Part 815:Superconductivity)

3 Terms and definitions

The following terms and definitions defined by IEC 60050-815 apply to this document:

ISO and IEC maintain a terminology database for standardization at the following address:

- IEC Electropedia: http://www:electropedia:org

- ISO online browsing platform: http://www:iso:org/obp

3:1

Residual resistance ratio residualresistanceratio;RRR The ratio of the resistance value at room temperature to the resistance value just above the superconducting transition temperature:

Note: This standard stipulates that the resistance of Nb-Ti and Nb3Sn composite superconductors at 293K (20°C) is room temperature resistance: The residual resistance ratio of the composite superconductor is

Formula (1) is calculated:

rRRR =

R1

R2 (1)

Where:

rRRR---the residual resistance ratio of the composite superconductor;

R1 --- the resistance of the composite superconductor at 293K (20°C);

R2 ---The resistance of the composite superconductor measured under the condition of no strain and no applied magnetic field just above the superconducting transition temperature:

Figure 1 shows a schematic diagram of the measurement curve of sample resistance versus temperature at low temperature:

GB/T 20831 | GB/T 23365 | GB/T 24488 | GB/T 43894.2 | GB/T 13221 | […]