The superconducting material with a nominal composition Bi1.6Pb0.4Sr2Ca2Cu3Oy has been synthesised. The annealing time varied from 18 to 168 h for the different tests. It is established that the increase of annealing time leads to a reduction in Pb content and an increase in the volume of the 110 K 2223 phase, in relation to the 85 K 2212 phase. The results of the investigation indicate that the introduction of Pb in the crystal lattice hardly contributes to the increase in 2223 phase. A more probable explanation is that Pb causes the formation of a medium that helps the transformation of the 2212 phase into the 2223 phase. © 1990 IOP Publishing Ltd.