This work investigates a new processing method developed to improve the connectivity of ex-situ MgB₂ bulks at low sintering temperatures. Mg additions (1–10 wt.%) were mixed to pre-synthesised MgB₂ to make composite powders that were sintered at 900 ^∘C by the field assisted sintering technique. Addition of 10 wt.% Mg resulted in a substantial increase in density from 68% to 79% and a dramatic reduction in MgB₄ from 11 to ∼0 wt.%. Pressure and dilatometry data recorded in-situ during the sintering process revealed that Mg additions led to different sintering mechanisms depending on the Mg fraction. For large Mg fractions (6 and 10 wt.%) a Mg liquid phase was formed and led to significant density improvements, and all pre-existing MgB₄ was transformed into MgB₂. A small amount of residual Mg remained in the bulks after the sintering process. Connectivity was improved with Mg additions, increasing four fold in the 10 wt.% Mg-MgB₂ sample compared to unmodified MgB₂. J _c values at low field were also significantly improved by Mg additions, in particular the 6 and 10 wt.% Mg-MgB₂ specimens showed J _c (20 K, 0 T) values 4–5 times higher than for unmodified MgB₂.

中文翻译：

---

通过新型液相烧结工艺改善 MgB2 体超导体的连通性

这项工作研究了一种新的处理方法，旨在提高迁地低烧结温度下的MgB _2块体。将 Mg 添加物（1-10 wt.%）混合到预合成的 MgB ₂中，制成复合粉末，然后通过现场辅助烧结技术在 900 ^{° C 下烧结。}_{添加 10 wt.% Mg 导致密度从 68% 显着增加到 79% 并且 MgB 4}从 11显着减少到 ~0 wt.%。记录压力和膨胀测量数据就地在烧结过程中，Mg 添加导致不同的烧结机制，具体取决于 Mg 分数。对于大的 Mg 分数（6 和 10 wt.%），形成 Mg 液相并导致密度显着提高，并且所有预先存在的 MgB ₄都转化为 MgB ₂。烧结过程后，少量残留的 Mg 残留在块体中。_{添加 Mg 后连接性得到改善，与未改性的 MgB 2}相比， 10 wt.% Mg-MgB ₂样品增加了四倍。杰 _C 添加 Mg 也显着改善了低场的值，特别是 6 和 10 wt.% Mg-MgB ₂样本显示杰 _C (20 K, 0 T) 值比未改性的 MgB ₂高 4-5 倍。