Sinter forging process was studied for production of sintered Bi-(Pb)-Sr-Ca-Cu-O superconductor having high Jc.
The effect of applied uniaxial stress, temperature, and sinter forging time on the sintering behavior, microstructural variation, and Jc were studied also.
Codecomposition of mixed nitrates of Bi,Sr,Ca,and Cu around 850℃ under low oxygen pressure led to the nearly single high-Tc phase. It was observed that the shear deformation and density of sintered body increased with temperature and pressure.
For example, the relative density of sinter forged body which was applied of relatively small uniaxial stress, $25Kg/cm^{2}$ at 850℃ for 5h was increased nearly 90%. This value is much higher than normal sintered specimen which is 60%. and enhancement of grain alignment is accompanied, too.
The transport critical current density (Jc) of sinter forged Bi-(Pb)-Sr-Ca-Cu-O superconductor at 850℃, 5h under uniaxial pressure of $25Kg/cm^{2}$ was $A/cm^2$. This Jc value is much larger than that of normal sintered specimen which is 45 $A/cm^{2}$. It is due to the densification and grain alignment by uniaxial pressing.
