STUDY OF THERMAL-EXPANSION OF BI-2212 AG TAPE CONDUCTORS USING ESEM/

Thermal expansion of Bi-2212 tapes dip coated on silver substrate was studied between room temperature and similar to 1000 K using an Electr oscan ESEM, equipped with a hot stage. We showed that this can be a si mple alternative technique when other conventional techniques have exp erimental difficulties because of the sample geometry and size. Extens ive shrinkage (more than 5%) was observed upon first heating of the gr een Bi-2212 which was removed from the silver substrate. The green com posite tape more or less followed the thermal expansion of silver tape on which it was coated. Thermal expansion of fully heat-treated Bi-22 12/Ag superconducting composite tape is similar to that of sliver tape up to about 650 K. Between similar to 650 K and similar to 1000 K the composite exhibits less expansion.