The Low-temperature superconducting material has a low critical temperature (Tc<30K), superconducting materials are working at liquid helium temperature. It is divided into metals, alloys and compounds.
Nb (niobium) is low-temperature superconducting metal with the practical value, and has been made into thin film materials in the field of weak electricity. The alloy system low-temperature superconducting material especially superconducting niobium rods is a beta phase solid solution, and Tc is above 9K.
The first study was NbZr alloy, and on this basis, the NbTi alloy appeared. The superconductivity and processing properties of NbTi alloy are better than that of NbZr alloy, and their use accounts for about 95% of the low-temperature superconducting alloys. NbTi alloy can be used in general difficult machining method of metal processing into alloy, and multi-core composite machining method with copper (or aluminum) for multi-core composite superconductor matrix, finally using metallurgical method to make the final transition from beta to single-phase alloy has a strong tie nail two-phase Center (alpha + beta) alloy to meet the requirement.
The compounds are NbN (Tc=16K), Nb3Sn (Tc=18.1K) and V3Ga (Tc=16.8K). NbN is mostly used in the form of thin film. Because of its good stability, it has been made into practical weak electric components. Nb3Sn is a brittle compound, which is prepared by solid state diffusion by V3Ga and pure copper or bronze alloy as matrix material. In order to improve the superconductivity of Nb3Sn (V3Ga) and improve its technological performance, some alloy elements, such as Ti and Mg, are sometimes added.
Low-temperature superconducting materials have been widely used. In strong magnetic field, NbTi superconducting material is used in high-energy physics accelerators and detectors, magnetic confinement of plasma, superconducting, superconducting motor and magnetic resonance imaging of the body instrument; Nb3Sn superconducting materials except for the production of a large number of small high field magnets (710T), also used to make magnet controlled nuclear fusion device in a few meters diameter; the low-temperature instrument is made of Nb and NbN films, has been used for the detection of very weak electromagnetic signals in military and medical fields.
Due to low Tc, low-temperature superconducting material, it must be used in liquid helium temperature, the operation cost is expensive, so its application is limited. Superconducting technology is the main body of superconducting materials. In short, superconducting materials are conductive materials with no resistance or little resistance. The unique property of superconducting materials is that electric energy will hardly lose during transportation. In recent years, with the development of material science, the performance of superconducting materials is constantly optimized, and the critical temperature of superconducting materials is higher and higher.