Influence of pelletization pressure on magnetic susceptibility samples of ceramics Bi (Pb)-Sr-Ca-Cu-O

The influence of pelletization pressing 100-500 MPa on the quality of the s amples from Bi1.7Pb0.3Sr2Ca2.5Cu3.5O10+delta superconducting transition was investigated. Samples which were pelletized at 100, 200, 300 MPa increased weight by an uncontrollable diffusion of elements from a filling. Obviousl y, these elements form additive phases on borders of grains, what is possib le to conclude from the dependence chi'-T The weight of samples pressed at pressure 400 and 500 MPa practically does not change at sintering. These sa mples after sintering within 250 h have a rather precise superconducting tr ansition from a magnetic susceptibility. XRD shows that the phase structure of samples differs insignificantly - after sintering time 250 h samples co nsist basically of a phase 2223. The powder of the same composition anneale d also within 250 h without a filling by results of XRD consists of approxi mately equal amounts of phases 2223 and 2212. (C) 1999 Published by Elsevie r Science B.V. All rights reserved.