Texture and Formation of (Bi,Pb)-2223 Phase in the Partial-Melting, Air-Cooling and Sintering Process

The texture and formation of (Bi,Pb)-2223 phase in the partial-melting, air-cooling and sintering process have been studied by means of XRD, SEM,EDS and AC susceptibility measurements. The 2223 phase with grain alignment of the c-axis in the region near surfaces of bulk samples of Bil.8Pb0.4Sr1.9Ca2.lCu3.5Oy has been achieved in the sintering process at 840 °C after the partial-melting at 875 °C for 1 hour and then air-cooling to room temperature. The 2201 phase with the c-axis alignment coexists with (Sr,Ca)2CuO3 and (Sr,Ca)CuO2 in surface layers of the sample just after the partial-melting and air-cooling. With increasing the sintering time after the partial-melting and air-cooling, the 2201 phase firstly transforms to the 2212 phase, and then to the 2223 phase. In such a 2201→ 2212→2223 transformation,if the 2201 phase is aligned, the 2212 and 2223 phases will still be aglined and their thicknesses of c-axis aligned layers increase.