Influence of on-off pulsed current pattern on processes during spark plasma sintering of MgB2 superconductor
G. Aldica,
V. Sandu,
S. Popa,
I. Pasuk,
M. Enculescu,
A.M. Ionescu,
P. Badica
Affiliations
G. Aldica
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
V. Sandu
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
S. Popa
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
I. Pasuk
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
M. Enculescu
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
A.M. Ionescu
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
P. Badica
Corresponding author. National Institute of Materials Physics, Atomistilor Street 405A, 077125, Magurele, Romania.; National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Romania
High density samples (92–94.5 %) of MgB2 were prepared by Spark Plasma Sintering (SPS). The on-off pulsed current patterns of SPS processing were 8–4, 12–2, 24–2, 99–1. Patterns with more on pulses favor formation of a higher amount of the secondary MgB4 phase through the decomposition of MgB2. They also promote enhancement of larger MgO crystallites without a strong increase in the amount of this phase. Densification rate and pressure in the SPS chamber show a similar behavior, but their amplitude varies and the temperatures defining different stages present some shifts. As-revealed differences induced by pulsed patterns impact superconducting properties in a complex manner. An attempt to assess correlations between the pattern and different superconducting parameters is presented.
