EFFECT OF HOT-PRESSING ON THE WEAK-LINK BEHAVIOR OF AG CLAD BI BASED SUPERCONDUCTING TAPES

The effect of hot pressing on the critical current density of Ag clad Bi based superconducting multifilamentary tapes was investigated. The critical current density for the hot-pressed tapes was significantly i mproved in comparison with the cold-pressed tapes. The enhancement of J(c) is essentially attributable to the improvement of strong links be tween grains. The hot pressing has also resulted in a very smooth inte rface between Ag and oxide core, reducing the random growth of grains into silver sheath. The ratio of I-c through strong links to the total I-c increases from 21% for cold-pressed tapes to 33% for the hot-pres sed ones. The SEM images show that the hot-pressed multifilamentary ta pe has higher density and better grain alignment than those without ho t pressing.