Published online by Cambridge University Press: 26 February 2011
Many processing parameters affect the critical current of silver-clad tapes of Bi2−xPbxSr2Ca2Cu3O10+y (2223) made by the powder in tube process. In this paper the effect of oxygen pressure during cooling from the final sintering step will be considered. It is shown that high oxygen pressures will destabilize the 2223 phase with formation of calcium plumbate and the lower Tc Bi2Sr2Ca1Cu2O8+y (2212) phase. This decomposition can drastically lower the critical current. It is shown that cooling in atmospheres containing about 5 % oxygen will avoid the calcium plumbate formation region.