PROCESSING CONSIDERATIONS FOR ADDING NANOMETER-SCALE OXIDES TO ENHANCE FLUX PINNING IN HIGH-TEMPERATURE SUPERCONDUCTORS

摘要

Several nanometer-scale oxide inclusions were added to Bi_2Sr_2CaCu_2O_x high-temperature superconductors to determine their effectiveness in creating intragranular flux-pinning sites. Powder pellets were fabricated and heat treated by partial-melt processing. Effects of the additives on melting response, superconducting properties, and microstructural development were examined. Al_2O_3 additions exhibited the most promise for forming stable pinning centers, ZrO_2 and SnO_2 additions were moderately promising, TiO_2, Fe_2O_3, and ZnO additions were less promising, and Y2O3 additions destroyed superconductivity.