Microstructure and Phase Equilibria along the Bi_(1.8)Pb_(0.4)Sr_(1.9)Ca_(n-1)Cu_nO_x Line between 820°C and 880°C

摘要

Microstructures and phase equilibria of the film samples and bulk samples along the line of Bi_(1.8)Pb_(0.4)Sr_(1.9)Ca_(n-1)Cu_nO_x (1 ≤ n ≤ 10) in the temperature range 820-880°C were studied. For compositions 1 ≤ n ≤ 1.2, all samples consist of the 2201 phase. For compositions 2 ≤ n, the samples air-cooled from a temperature above 865°C mainly consist of the 2201 phase, whereas the samples furnace-cooled from above 865°C mainly consist of the 2212 phase. For compositions 2.5 ≤ n, the 2223 phase appears in the samples annealed in the temperature range 820-855°C for more than 18 hours.