  Literature and experimental data about practical determination of phase
composition and structure of BiHTSC ceramics from results of measurements of
temperature dependence of magnetic susceptibility are presented. It is shown
that Bi2223 to Bi2212 phases ratio, calculated by XRD-analysis results, does
not correlate precisely with magnetic susceptibility - temperature dependence.
Phase, which is present in smaller amount, especially Bi2212 phase with lower
critical temperature, appears less pronouncedly at the magnetic susceptibility
- temperature dependence. Besides, limiting parts of Meissner effect
manifestation are peculiarities of contacts of superconducting grains.
Different kinds of such contacts lead to lowering the critical temperature
together with conservation of narrow transition interval, to division of
transition into stages, and to increasing of transition interval. Among
negative consequences of this influence there are hindrances in realization of
grain oriented Bi ceramics synthesis scheme which imply powdering of samples
consisting of chaotically evolved grains of Bi2223 phase, ordered placement of
obtained plate grains of this phase - for example, through vibration
compacting, and sintering.
