Effect of Sn Concentration in Bronze Matrix on the Pre-Reaction Formation of Nb3Sn Layers in Bronze-Processed Superconducting Strands of Different Design
| Autor: | Anastasiia Tsapleva, Elena Popova, I. M. Abdyukhanov, E.G. Valova-Zaharevskaya, Maxim Alexeev, I. L. Deryagina, E. I. Patrakov |
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| Rok vydání: | 2018 |
| Předmět: |
Superconductivity
Materials science Scanning electron microscope Reaction formation Annealing (metallurgy) 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology Condensed Matter Physics Tin bronze Electronic Optical and Magnetic Materials chemistry.chemical_compound 020303 mechanical engineering & transports 0203 mechanical engineering chemistry engineering High field Electrical and Electronic Engineering Niobium-tin Bronze Composite material 0210 nano-technology |
| Zdroj: | IEEE Transactions on Applied Superconductivity. 28:1-5 |
| ISSN: | 1558-2515 1051-8223 |
| Popis: | The goal of this paper is to study and analyze the effect of Sn concentration (14% or 16%), the mode of Ti-doping and the shape of Nb filaments on the thickness of the “parasitic” layers of prereacted Nb 3Sn grains (formed before the diffusion annealing) in the ITER-type strands and strands for high field applications processed by bronze technology. The use of short (of total duration not more than 1 h) intermediate heat treatments at 500 °С does not allow avoiding the prereaction formation of Nb3Sn in all the samples under study. Sn concentration in bronze decreases by 1.5–2.0% after heat treatments compared to the initial state in all samples. In the samples with Ti-doped bronze matrix and coupled Nb filaments, the average thickness of “parasitic” layers is 112 nm in the case of 14% Sn in bronze and 140 nm for a bronze matrix with 16% Sn. In the sample with 16% Sn in matrix and extended Nb filaments of intricate shape the average thickness of prereacted layers reaches 200 nm. It is concluded that to minimize the parasitic layers formation the strands with high tin bronze matrix should be subjected to short intermediate heat treatments at temperatures lower than 500 °C. |
| Databáze: | OpenAIRE |
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