Intermediate phases in superconducting niobium-tin alloys

Journal Article · Sun Jul 01 04:00:00 EDT 1962 · Journal of Research of the National Bureau of Standards, Section A: Physics and Chemistry

DOI:https://doi.org/10.6028/jres.066A.037· OSTI ID:4826890

Wyman, L. L.; Cuthill, J. R.; Moore, G. A.; Park, J. J.; Yakowitz, H.

In attempting to produce superconducting wire of the niobium sheath Nb/ sub 3/Sn core type, metallogmaphic examination showed that such material are heterogeneous and contain a number of intermediate phases. Detailed metallographic studies were made on diffusion zones in which tin was allowed to react with porous niobium blocks, with fused niobinm rod, and with niobium wires, and on a number of reacted powder mixtures. The phases produced were identified by anodizing to characteristic colors and by microspot analysis, supplemented by some hot-stage microscope and thermal analysis tests. A tentative revised diagram is offered to illustrate the types of reactions which occur in the system. The presumably desired phase, Nb/sub 3/Sn, is found to lie between the more easily formed phases Nb/sub 4/Sn and Nb/sub 2/Sn/sub 3/, which are stable to temperatures well above the peritectoid decomposition of the Nb/sub 3/Sn. At lower temperatures the compound Nb/sub 2/Sn is formed. It is indicated that the high-temperature treatment to react niobium and tin should be followed either by very slow cooling or by an anneal in the 600 to 700 deg C range to form Nb/sub 3/ Sn,

• Research Organization: Originating Research Org. not identified
• Sponsoring Organization: USDOE
• NSA Number: NSA-16-025791
• OSTI ID: 4826890
• Journal Information: Journal of Research of the National Bureau of Standards, Section A: Physics and Chemistry, Journal Name: Journal of Research of the National Bureau of Standards, Section A: Physics and Chemistry Journal Issue: 4 Vol. 66A; ISSN 0022-4332
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

DIFFUSION
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
MIXING
NIOBIUM
NIOBIUM ALLOYS
PHASE DIAGRAMS
POROSITY
POWDERS
PRODUCTION
RODS
SUPERCONDUCTIVITY
TIN ALLOYS
WIRES
ZONES