Change of the Bi-2223 Phase by Repeat of Mechanical Grinding and Heat Treatment

Abstract

The change of the Bi-2223 phase Bi_1.8Pb_0.4Sr_2.0Ca_2.0Cu_3.2O_z with repeat of mechanical grinding and heating at 850°C in air has been studied mainly by XRD. The repeat of the process leads to the decrease of the 2223 phase and formation of the 2212 phase, (Ca, Sr)₂CuO₃ and (Sr, Ca)₃Cu₅O_x. This change depends upon two experimental factors : the accumulative heating period and the number, N, of repeat. The former bring more significant effects than the latter. The Pb concentration in the samples was found to decrease as N increased. The change of the 2223 phase mentioned above can be interpreted by the decrease in the Pb concentration in the samples.