GB/T 21546-2008 in English

《GB/T 21546-2008铌钛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。
本标准是首次发布。本标准是根据国际电工委员会制定的国际标准IEC 61788-1：2006《铌钛复合超导体的直流临界电流测量》制定的，在技术内容上与该国际标准等同。为了使用者了解本标准中的术误和GB/T 13811-2003《电工术语超导电性》的对应关系，本标准中各术语的条目中都注明有GB/T 13811-2003的条目编号。GB/T 13811-2003与国际电工委员会制定的国际标准IEC 60050（815）在技术内容上等同。本标准规定了铌钛复合超导体的直流临界电流测量的原理、要求、测量装置、样品、测试步骤、结果计算等

Scope

This standard test method is applicable to the determination of the DC critical current of a copper/niobium-titanium (Cu/Nb-Ti) composite superconductor with a copper-to-super ratio greater than 1, and is also applicable to the determination of a niobium-titanium core wire with a diameter greater than 1 μm and a copper-to-titanium ratio greater than 1. 0.9. DC critical current of copper/copper nickel/niobium titanium (Cu/Cu-Ni/Nb-Ti) superconducting wire with copper-nickel alloy (Cu-Ni)-superconductor ratio greater than 0.2. Since the critical current test methods of copper/niobium-titanium (Cu/Nb-Ti) composite superconductors and copper/copper-nickel/niobium-titanium (Cu/Cu-Ni/Nb-Ti) superconductors are slightly different, Appendix C of this standard (Normative) The special regulations to be followed when measuring copper/copper nickel/niobium titanium (Cu/Cu-Ni/Nb-Ti) superconductors will be introduced. This standard test method is applicable to superconductors whose magnetic field is less than or equal to 0.7 times the critical magnetic field above it, whose critical current is less than 1000A, and whose n value is greater than 12 under standard test conditions. During measurement, the sample to be tested should be immersed in liquid helium at a known temperature. The conductor to be tested should be an integrated superconducting wire with a circular or rectangular cross-section, and its cross-sectional area is less than 2mm². The sample to be tested should have a helical coil geometry. This standard also gives the allowable deviation and other specific limits for this test method in routine testing. Conductors with a critical current greater than 1000A or a cross-sectional area greater than 2mm² can also be measured by this method, but the measurement uncertainty will increase and the self-field effect will be more obvious (see Appendix B). Furthermore, for simplicity and to keep measurement uncertainties relatively low, this standard does not address special sample shapes that may be more suitable for conductors with large cross-sections. The measurement method given in this standard can be applied to determine the critical current of other types of composite superconducting wires with proper modification.