The problems and achievements in the determination of the phase composition of solid multielement multiphase inorganic compounds are considered. The problems of theory, methodology and practical use of two chemical methods of phase analysis, selective dissolution and standard-free stoichiographic dissolution are discussed. The unique potential of stoichiography and differentiating dissolution method, which allows one to overcome many limitations and difficulties typical of modern phase analysis techniques, are demonstrated. Examples of using differentiating dissolution for the phase analysis of diverse compounds and functional materials are given.

Stoichiography and chemical methods of phase analysis of multielement multiphase compounds and materials

The influence of additions of gold (5 and 10 at. %) on the lattice parameters, the superconducting transition temperature, and the diamagnetic susceptibility of the high-temperature superconducting ceramic YBa2Cu3O7−δ is investigated. The influence of gold on the kinetics of the release of weakly bound oxygen during heating of the ceramic in a vacuum is also studied. It is shown that doping the ceramic with gold causes uniaxial expansion of the lattice of the material, a significant decrease in the diamagnetic susceptibility, and nonmonotonic variation of the kinetic parameters of the oxygen release, while the superconducting transition temperature remains nearly unchanged.

N.F. Zakharchuk

Papers

The effect of the substitution of Cu(1) by dopants on oxygen content and superconductivity in Y(123)