New Synthesis Route for Complex Borides; Rapid Synthesis of Thermoelectric Yttrium Aluminoboride via Liquid-Phase Assisted Reactive Spark Plasma Sintering

摘要: YxAlyB14 ceramics are of high interest as temperature thermoelectric materials with excellent p, n control. In this study, direct synthesis dense polycrystalline (x ~0.64, 0.52 ≤ y ≤ 0.67) was successfully carried out by spark plasma sintering using commercially available precursors. YB4, AlB2 and B powders were reactively sintered an additive AlF3 at 1773 K for 5–60 min in reduced Ar atmosphere. The sinterability remarkably enhanced liquid phase comparing to conventional techniques. Phase composition analysis X-ray diffraction showed that main peaks belong the MgAlB14 structure type no detected. behavior changed from p-type n-type increasing Al occupancy. Power factor ZT values measured study found be same range best previously reported. This original process is less precursor-consuming compared previous processes, strikingly, time-consuming, time, shortened 8 h 5 min 1 h n-type. total time ≥3 days ~4–5 h. discovery opens door more accessible complex borides.