GB/T 28871-2012 in English

《GB/T 28871-2012铌三锡（Nb3Sn）复合超导体的直流临界电流测量》由TC265（全国超导标准化技术委员会）归口，主管部门为中国科学院。

Scope

This standard also gives the allowable deviation and other specific limitations of this test method in common tests. Niobium-three-tin (Nb₃Sn) superconductors with a critical current greater than 1000A or a total cross-sectional area greater than 2mm² can also be measured by this method, but the expected precision will be reduced and the self-field effect will be more obvious (see Appendix C). This standard test method is applicable to the determination of the DC critical current of the niobium-three-tin (Nb₃Sn) composite superconductor produced by the bronze method or the internal tin method with a copper/non-copper ratio greater than 0.2. This standard test method is applicable to superconductors whose critical current is less than 1000A and whose n-value is greater than 12 under standard test conditions, and the magnetic field of the superconductor is less than or equal to 0.7 times the upper critical magnetic field. During the measurement, the measured sample is immersed in liquid helium at a known temperature. The tested niobium-three-tin composite conductor has an integrated structure with a circular cross-section, and its cross-sectional area is less than 2mm². The sample to be tested shall be of induction coil geometry. In addition, for simplicity and to maintain measurement precision, this standard does not address special sample shapes that may be more suitable for conductors with large cross-sections. The measurement methods given in this standard should also be applicable in principle to niobium-three-tin (Nb₃Sn) composite superconducting wires produced by any other process. After appropriate modification, the method is also expected to be applicable to other types of composite superconducting wires.