Progress in Superconductivity and Cryogenics (한국초전도ㆍ저온공학회논문지)

The Korean Society of Superconductivity and Cryogenics (한국초전도저온학회)
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Reaction temperature dependence of MgB2 superconducting bulks using the different sizes of Mg raw powders

  • K.C., Chung (Korea Institute of Materials Science)
  • Received : 2022.12.05
  • Accepted : 2022.12.20
  • Published : 2022.12.31
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Abstract

Since the MgB2 superconductor is simply composed of two constituents of Mg and B, its performance can be monitored easily with the change of one ingredient compared to the other. With the powder size of B less than 100 nm, two different sizes of Mg powders are used to investigate the reaction temperature dependence of MgB2 bulk samples. In the range of 630-700℃ for the duration of 30 min., the un-reacted Mg is seen only at 630℃ with Mg powder size of <5 ㎛, whereas Mg traces are detected at all the temperature range with Mg powder size of <45 ㎛. The reaction temperature dependence of MgB2 superconducting transition temperature, Tc, shows little difference whether Mg powder size is large or small in this range except for the 630℃. It is worthy of notice that the critical current densities of MgB2 show higher performance with the small size of Mg compared to the large one at all field ranges. With the Mg powder size of <45 ㎛, flux pinning is enhanced with decreasing the reaction temperature, whereas flux pinning properties is quite similar in the Mg powder size of <5 ㎛ except for the 630℃, where Mg is left behind after the reaction.

Keywords

Acknowledgement

This work was supported by Industrial Technology Innovation Program (Grant No. 10053590) funded by the Ministry of Trade, Industry and Energy (MOTIE), Korea.

References

  1. Rene Flukiger, et al., "MgB2 Superconducting Wires; Basics and Applications," World Scientific Publishing, 2016. 
  2. J. H. Kim, et al., "Tailed materials for high-performance MgB2 wire," Adv. Mater., vol. 23, pp. 4942-4946, 2011.  https://doi.org/10.1002/adma.201101243
  3. HITACHI news & events, "Development of 8-km-long Magnesium Diboride Superconducting Wire," https://www.hitachi.com/rd/news/topics/2019/1016.html, Oct. 16, 2019. 
  4. J. H. Kim, et al., "Microscopic role of carbon on MgB2 wire for critical current density comparable to NbTi," NPG Asia Materials, vol. 4, pp. e3, 2012. 
  5. S. Ye, et al., "Fabrication of MgB2 superconducting wires with a hybrid method combining internal Mg diffusion and powder in tube processes," Supercond. Sci. Technol., vol. 27, pp. 055017, 2014. 
  6. X. Xu, et al., "Effect of boron powder purity on superconducting properties of MgB2," Supercond. Sci. Technol., vol. 19, pp. 466, 2006. 
  7. A. Bateni, et al., "High-quality MgB2 nanocrystals synthesize by using modified amorphous nano-boron powders: Study of defect structures and superconductivity properties," AIP Advances, vol. 9, pp. 045018, 2019. 
  8. Y. Hishinuma, et al., "Effect of boron particle size on microstructure and superconducting properties of in-situ Cu addition MgB2 multifilamentary wire," Journal of Physics: Conference Series, vol. 507, pp. 022009, 2014. 
  9. D. N. Kim, et al., "Effects of the size of Mg powder on the formation of MgB2 and the superconducting properties," Progress in Superconductivity and Cryogenics, vol. 18, no. 4, pp. 9-14, 2016.  https://doi.org/10.9714/psac.2016.18.4.009
  10. B. B. Sinha, et al., "Evaluation of Mg size dependence on supercondivtity of MgB2," Progress in Superconductivity and Cryogenics, vol. 15, no. 2, pp. 39-43, 2013. https://doi.org/10.9714/PSAC.2013.15.2.039