Growth of Nb₃Sn coating in tin vapor-diffusion process

Journal Article · Wed Aug 28 00:00:00 EDT 2019 · Journal of Vacuum Science and Technology A

DOI:https://doi.org/10.1116/1.5113597· OSTI ID:1559033

Pudasaini, Uttar ^[1]; Eremeev, Grigory V. ^[2]; Angle, Jonathan W. ^[3]; Tuggle, Jay ^[3]; Reece, Charles E. ^[2]; Kelley, Michael J. ^[4]

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1. The College of William and Mary, Williamsburg, VA (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
3. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
4. The College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

The potential of Nb₃Sn for superconducting radio frequency (SRF) cavities is widely recognized and renewed R&D efforts continue to bring new insights about the material's structure and properties. Here, we have systematically coated niobium with Nb₃Sn for different durations, and several of them were coated over ("overcoat") multiple times, to elucidate the growth kinetics of Nb₃Sn during tin vapor diffusion process. Analysis of coated samples is consistent with the model in which tin diffuses via grain boundaries to the Nb₃Sn-Nb interface, where the growth of Nb₃Sn into the Nb bulk takes place. Similar scaling laws were found for Nb₃Sn grain growth and layer thickness. Non-parabolic layer growth is consistent with significant grain growth, which reduces the number of Sn transport channels. Examination of patchy region in Nb₃Sn coating, revealing large single crystalline grains, points to impeded Nb₃Sn layer growth due to low grain boundary density, resulting in a significantly thinner coating in those areas.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
• Grant/Contract Number: AC05-06OR23177; SC0014475; SC0018918
• OSTI ID: 1559033
• Alternate ID(s): OSTI ID: 1559067
• Report Number(s): DOE/OR/23177--4676; JLAB-ACC--19-2931
• Journal Information: Journal of Vacuum Science and Technology A, Journal Name: Journal of Vacuum Science and Technology A Journal Issue: 5 Vol. 37; ISSN 0734-2101
• Publisher: American Vacuum Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Nb3Sn
SRF cavity
grain boundary diffusion
grain growth
growth kinetics
vapor diffusion