High-T-c superconducting membrane: (II) nanosized superconducting particles into alpha-alumina support

Porous superconducting membranes were realized by the electrophoretic depos ition of bismuth cuprate colloid precursors. In order to prepare supercondu cting colloidal suspension, the high Tc bismuth cuprate superconductor, Bi2 Sr2CaCu2O8+y or Bi2Sr2Ca2Cu3O10+y, should first be intercalated with mercur y iodide molecules and subsequently with organic compounds such as pyridine and alkylpyridinium to induce interlayer complexes like bis(alkylpyridiniu m)tetraiodomercury and bis(Py)diiodomercury. Finally, the resulting organic complex intercalates were dispersed in an organic solvent to form supercon ducting colloids with an average particle size of similar to 200 nm. Gas se paration membranes were prepared by the filtration of superconducting nano particles through an a-alumina support. Their physical properties such as s uperconductance, porosity and pore size were measured by SQUID and mercury porosimetry, respectively, and their morphology and thickness were checked by SEM. The gas permeation experiments for nitrogen and oxygen mixture were performed at liquid nitrogen temperature.