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M.S.A. Hossain , C. Senatore, R. Flükiger, M. Tomsic, S. X. Dou

Effect of Starting Materials and Present State of Cold Densified MgB 2 wires for Industrial Scale-up. M.S.A. Hossain , C. Senatore, R. Flükiger, M. Tomsic, S. X. Dou. Superconductivity Symposium, Izmir– 05/07/2011. Outline. Part: 1 Effect of starting materials on MgB2 superconductor Part: 2

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M.S.A. Hossain , C. Senatore, R. Flükiger, M. Tomsic, S. X. Dou

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  1. Effect of Starting Materials and Present State of Cold Densified MgB2 wires for Industrial Scale-up M.S.A. Hossain, C. Senatore, R. Flükiger, M. Tomsic, S. X. Dou Superconductivity Symposium, Izmir– 05/07/2011

  2. Outline • Part: 1 • Effect of starting materials on MgB2 superconductor • Part: 2 • Cold High Pressure Densification: Higher mass density • Binary MgB2 Wires • MgB2 Wires with additives • Towards Longer wire lengths of densified MgB2 wires Superconductivity Symposium, Izmir– 05/07/2011

  3. Part: 1 Effect of starting materials on MgB2 superconductor Superconductivity Symposium, Izmir– 05/07/2011

  4. Supercond. Sci. Technol. 23 (2010) 075014 Superconductivity Symposium, Izmir– 05/07/2011

  5. 99% nano size amorphous with excess Mg 99% nano size amorphous stoichiometric 97% crystalline Supercond. Sci. Technol. 23 (2010) 075014

  6. 99% nano size amorphous 97% crystalline with high annealing temp 97% crystalline with low annealing temp Supercond. Sci. Technol. 23 (2010) 075014

  7. JOURNAL OF APPLIED PHYSICS 105, 103913 (2009)

  8. JOURNAL OF APPLIED PHYSICS 105, 103913 (2009)

  9. Part: 2 Cold High Pressure Densification: Present State Superconductivity Symposium, Izmir– 05/07/2011

  10. 2 ways to improve the properties of MgB2 superconductors : • Intrinsic (homogeneous dopant induced Hc2 enhancement) • Extrinsic (reduced porosity i.e better connectivity between grains) • Collingset al. Sust 21 (2008) 103001] Superconductivity Symposium, Izmir– 05/07/2011

  11. Application of High Pressures on in situ MgB2 Hot Pressing (during reaction) HIP 0.2 GPa Tapes Serquis et al., 2003 Metallicanvils > 0.2 GPaBulksamplesPrikhna et al., 2008 Hot pressing 0.1 GPa Tapes Kumakura et al., 2008 Hot Pressing 0.1 GPa Tapes Yamada et al., 2006 Cold Pressing (before reaction) P = 0.1 GpaBulksamples Matsushita (2008): littleeffect P > 1 GPaWires and Tapes Presentwork: Higher mass density (Connectivity) Higher Jc Reduced electrical resistivity

  12. Binary MgB2 : Applying Pressures from 4 sides on square wires. 1.0 mm 1.0 mm Drawn to a square cross section After cold densification at 2 GPa The directional elongated morphology of the Mg is always visible in cold deformed Mg+B powder mixtures

  13. Binary MgB2 : Higher mass density due to volume contraction

  14. Binary MgB2 : CHPD improves grain connectivity Hossain MSA, Supercond. Sci. Technol. 22 (2009) 085002 (7pp)

  15. Binary 18-filament MgB2 wire: CHPD applied A. B. 0 GPa 1.5 GPa

  16. Jcvs. B at 4.2, 20 and 25 K for 18-filament binary MgB2 wires densified at 1.5 Gpa on short and15cm long samples Hossain MSA, Supercond. Sci. Technol. 26(2011) 085002 (7pp) 2nd International Forum, ISEM, UOW – 28/03/2011

  17. MgB2 wires, doped with 10 wt.% C4H6O5 NbTi: Jc = 1 x 105 A/cm2 at 8T/4.2K compression Almost isotropic behavior Hossain MSA, Supercond. Sci. Technol. 22 (2009) 095004 (8pp)

  18. OSU measurement: MgB2 wires, after 1.8 Gpa, Alloyed with 10 wt.% C4H6O5 At 20K, Jc = 10^4 A/cm2 at >7T!!!

  19. Comparison of various additives used in MgB2 wires after CHPD

  20. … as a consequence, also the n value of I-V curve is increased CHPD improves the homogeneity of Jc in the s/c layer MgB2 - 650C/1h MgB2 - 650C/1h Accepted by IEEE transactions on Applied Superconductivity

  21. n-factor improves in both binary and alloyed MgB2 sample after CHPD: Accepted by IEEE transactions on Applied Superconductivity

  22. First test on densification of longer wire lengths (1 meter) by means of an automatic press/release/advance mechanism Accepted by IEEE transactions on Applied Superconductivity

  23. Industrially Potential Isotropic wires

  24. Still lot to do……. The further improvement of MgB2 conductors involves the following main factors, i) the availability of amorphous, high purity Boron powder with sizes in the 100 nm range, ii) the optimization of mass density in MgB2 filaments, by improved densification methods, iii) the enhancement of the filling factor, which is at present higher for in situ wires than for IMD processed wires, and iv) further studies on cold deformation are needed in order to obtain wires with smaller filament diameters for reducing the losses in AC applications.

  25. Summary Cold High Pressure Densification determines a strong enhancement of Jc in binary and alloyed MgB2 wires due to higher mass density inside the filament. Resistivity decreases, resulting in an increased current-carrying cross section Homogeneity is improved and thus the n value of I-V curve is increased Square MgB2 wires with practically isotropic properties exhibited the highest value of Jc reported so far: B(104) = 13.4// / 12.95┴ T at 4.2K. B(104) = 7.1///6.7┴ T at 20K CHPD has the potential for the production of long length MgB2 wires

  26. Applied Superconductivity Energy Storage Group Terahertz Science, Solid State Physics Group Thin Film Technology Group Nano Structured Materials Spintronic and Electronic Materials Group Advanced Photovoltaic Materials

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