Critical Properties of Bi Superconducting Wire with Cooling Condition in the Sintering Process.

후열처리 과정에서 냉각조건에 따른 Bi계 초전도선재의 임계특성

To study on the superconducting properties with cooling conditions, silver-sheathed Bi-Pb-Sr-Ca-Cu-O wires fabricated by the powder-in-tube method. The wires cooled down in the furnace, air and liquid NS12T after sintering at 840$^{\circ}C$ Critical current density of sample cooled in the furnace is 5.1${\times}$10S03TA/cmS02T and sample cooled in the air is 40A/cmS02T at 77K, zero magnetic field. The latter is very low critical current density of Bi system. 2223 high-Tc superconducting phase of sample cooled in the air was distroyed. Properties of sample cooled down in the liquid nitrogen is the same as cooled in the furnace.