Ex Situ Spark Plasma Sintering of Short Powder-in-Tube MgB{sub 2} Tapes with Open and Closed Ends
Short powder-in-tube tapes of MgB{sub 2} in the Fe sheath were fabricated by ex situ route from a commercial powder containing some free Mg and MgO impurity phases. The final heat treatment was performed by spark plasma sintering (SPS). Tapes were with open (OT) or closed (CT) endings. Closed endings were made by folding and pressing. The MgB{sub 2} core of the OT sample has shown a higher low-field critical current density, a higher maximum pinning force, a slightly higher disorder, smaller average MgB{sub 2} crystallite size, a weak contact between Fe and MgB{sub 2} core, and more macro-flux jumps. The upper and irreversibility fields were similar for OT and CT samples. In the center of the MgB{sub 2} cores, the detected impurity phase is MgO, while at the interface with Fe, MgB{sub 4} also occurs. Impurity phases found at interface, MgO and MgB{sub 4}, are present in the center of the bulk SPSed samples. Reactions and pinning-force-related parameters are discussed with respect to Mg behavior influenced by condition of endings. It is inferred that the presence of free Mg in the raw MgB{sub 2} powder has an important contribution to observed differences, and its removal or control is recommended.
- OSTI ID:
- 22773660
- Journal Information:
- Journal of Superconductivity and Novel Magnetism, Vol. 31, Issue 11; Other Information: Copyright (c) 2018 Springer Science+Business Media, LLC, part of Springer Nature; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); ISSN 1557-1939
- Country of Publication:
- United States
- Language:
- English
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