Fabrication and Superconducting Properties of Highly Dense ${\rm MgB}_{2}$ Bulk Using a Two-Step Sintering Method

Optimization of sintering conditions in bulk MgB2 material for improvement of critical current density

“…Further, one can improve the bulk MgB 2 material performance by optimizing the sintering time at 805 C. It has been demonstrated that sintering process specially optimum sintering time and sintering temperatures are both very important to improve the critical current density of bulk MgB 2 material without any doping. Note that the present critical current values especially in low fields at 20 K are high as compared to the recently reported sinter bulk MgB 2 materials, or MgB 2 superconducting bulk fabricated by capsule method or bulk MgB 2 materials produced by using SiC particles or double step sintering process [24]. Hence, the optimum low temperature sintering and time is a promising and potentially effective to improve the performance of sintered bulk MgB 2 material, which is quite beneficial for the batch production of the sintered bulk MgB 2 for several real industrial applications.…”

“…In bulk materials, the further enhancement of J c was reported for samples sintered with a two step temperature process and it was found that a lower second-step annealing temperature results in higher J c . It is noticeable that the J c value of the samples heat-treated for 0.1 h at 1100 C and 6 h at 770 C approached the value of 14 A/cm 2 at 3.5 T, 20 K [24]. Pyrene lumps as carbon source were also used to improve critical current density of MgB 2 material and it was found that oxygen free pyrene gas diffusion into the bulk resulted in a self field J c at 20 K being dramatically improved to around 10 6 A/cm 2 [25].…”

In-field Jc improvement by oxygen-free pyrene gas diffusion into highly dense MgB2 superconductor

“…In our earlier study, 10,11 two-step processing via magne-sium diffusion was suggested to be the easiest way to make a highly dense sample with enhanced low field J c . In the present work, lumps of pyrene ͑C 16 H 10 ͒, an oxygen-free hydrocarbon, were selected as a C source in combination to the Mg diffusion process.…”