Characterization of baria-alumina-silica glasses and YBa2Cu3O7-x superconducting films prepared by the sol-gel process

Abstract

The preparation of eutectics in the system BaO-Al2O3-SiO2 by the conventional technique is carried out by fusions with intermittent crushing and grinding. Hydrolysis and polycondensation of alkoxides in a suitable solvent provide a simple way to obtain the homogeneous baria-alumina-silica glasses. The physical and chemical changes which occur during the gel-to-glass conversion were investigated on gel powders by thermal gravimetric analyses, differential thermal analyses, mass spectroscopy, nitrogen sorption analyses, and dilatometry. By means of the sol-gel route it is also possible to prepare coating solutions in the Y-Ba-Cu-system. Coatings of composition YBa2Cu3O(-7x) were deposited on substrates using dip coating and characterized by scanning electron microscopy and measurements of superconducting temperature.