Application of Copper Thermal Spraying for Electrical Joints between Superconducting Nb3Sn Cables
| Autor: | Vincenzo D’Auria, Pierluigi Bruzzone, Mickael Sebastian Meyer, Enrique Rodriguez Castro, Stefano Sgobba |
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| Předmět: |
Technology
Microscopy QC120-168.85 QH201-278.5 microstructure superconducting magnets electrical joints electric arc spraying Engineering (General). Civil engineering (General) Accelerators and Storage Rings Article TK1-9971 Descriptive and experimental mechanics General Materials Science Electrical engineering. Electronics. Nuclear engineering TA1-2040 |
| Zdroj: | Materials, Vol 15, Iss 125, p 125 (2022) Materials; Volume 15; Issue 1; Pages: 125 Materials |
| Popis: | This manuscript reports on the application of copper thermal spraying in the manufacturing process of an electrical connection between Nb3Sn cables for superconducting magnets of fusion reactors. The joint is realized through diffusion bonding of the sprayed coating of the two cables. The main requirement for such a connection is its electrical resistance, which must be below 1 nΩ at B = 8 T, I = 63.3 kA and T = 4.5 K. Micrographs of the joint prototype were taken to relate the joint resistance with its microstructure and to provide feedback on the manufacturing process. Optical microscopy (OM) was used to evaluate the grain size of the coating, presence of oxide phases and to analyze the jointed surfaces. Scanning electron microscopy (SEM) and, in particular, energy-dispersive X-ray spectroscopy (EDX) were used to confirm the elemental composition of specimens extracted from the prototype. It is shown that the copper coating has an oxide concentration of 40%. Despite this, the resistance of the prototype is 0.48 nΩ in operating conditions, as the oxides are in globular form. The contact ratio between the jointed surfaces is about 95%. In addition, residual resistivity ratio (RRR) measurements were carried out to quantify the electrical quality of the Cu coating. |
| Databáze: | OpenAIRE |
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