Study of microstructure as a function of the processing of
doped MgB2
A. H. Yonamine1, F. L. Zabotto2, J. A. Eiras2, S. Zhou3, S. X. Dou3, M. J. Saeki4, D. I. dos
Santos5
1
POSMAT/UNESP – Univ Estadual Paulista, SP, Brazil
Ufscar, DF, Grupo de Cerâmicas Ferroeléticas, SP, Brazil
3
Institute for Superconducting and Electronic Materials, Australia
4
UNESP – Univ Estadual Paulista Botucatu, IBB, MAv, SP,Brazil
UNESP – Univ Estadual Paulista Bauru, DF, MAv – LMSCN, SP,Brazil
2
5
Nowadays, the superconducting MgB2 is not any more considered a promising
material but already an industrial product [1]. Its great potential is due to its relatively high
transition temperature and reasonable upper critical field values [2], besides low material cost
and simple fabrication process in comparison with conventional superconductors like Nb3Sn,
Nb-Ti alloys and HTSC [3].
More recently, the low mass density of MgB2 became one of the most focused
problems to be solved aiming a conventional and low cost processing. In this way, MgB2 has
been studied to improve its microstructure properties.
In this work the microstructure characteristics of several carbon compounds doped
MgB2 are studied by various techniques like XRD, thermal analysis, dilatometry, nitrogen
adsorption and scanning electron microscopy. A new carbon doping (hydrocarbon, C8H18), as
well as two of the most successful used doping (SiC and silicon oil) were sintered to high
mass density and compared for their microstructure properties. Magnetization measurements
were also performed in order to evaluate the new doping.
The XRD and the thermal analysis recorded the temperature and the phase formation
of MgB2 during the heat treatment. The dilatometer curves showed the best annealing
temperature to have the highest contraction. By the nitrogen adsorption measurements and by
SEM was possible to compare their BET surfaces, textures and microstructures. The
used
processing of these materials did not improve Jc of these samples, but the new micro structural
data showed to be important for further works.
Acknowledgement: The authors which to thank CNPq for the scholarship.
[1] A. Malagoli; V. Braccini; C. Bernini; G. Romano; M. Vignolo; M. Putti; C. Ferdeghini;
Supercond. Sci. Technol. 23, 025032 (2010).
[2] B. B. Sinha; M. B. Kadam; M. Mudgel; V. P. S. Awana; H. Kishan; S.H. Pawar; Physica
C. 470, 25–30 (2010).
[3] X. Zhang; D. Wang; Z. Gao; L. Wang; Y. Qi; Z. Zhang; Y. Ma; S. Awaji; G. Nishijima;
K. Watanabe; E. Mossang; X. Chaud; Supercond. Sci. Technol. 23, 025024 (2010).
e-mail: [email protected]