INFLUENCE OF COLD PROCESSING AND HEAT TREATING TECHNOLOGY ON MICROSTRUCTURE AND CRITICAL CURRENT DENSITY OF BiPbSrCaCuO/Ag COMPOSITE SUPER-CONDUCTING STRIP MATERIALS

BiPbSrCaCuO/Ag(2223) composite high temperature super-conducting strip materials have been prepared by powder-in-tube technique. The influence of cold processing and heat treating(sintering) technology on the microstructure and critical current density of strip materials have been studied. The microstructure and critical current density Jc value of strip materials are closely related with cold processing deformation and sintering condition. Jc value of drawn and roiled strips as obviously increased after single action pressing. Reasonable sintering condition is at 840~850℃ for 100~200h with a cooling rate of 50~100℃/h. Maximum critical currentdensity Jc under zero magnetic field at 77.3K is 1.33×10⁸A/m².