Growth characteristics of ZrO₂ insulation coatings on Ag/AgMg sheathed Bi-2212 superconducting tapes

We have investigated the growth behaviors of high temperature compatible ZrO₂ insulation coatings on Ag and AgMg sheathed Bi ₂Sr₂Ca₁Cu₂O_x superconducting tapes depending on number of dipping and thermal conditions. The coatings were fabricated on long-length superconducting tape substrates using a solution derived from Zr tetrabutoxide, solvent and chelating agent for high magnetic field magnets. The layer-on-layer growth behaviors were characterized by environmental scanning electron microscope (ESEM), energy dispersive spectroscopy (EDS), X-ray maps and X-ray diffraction (XRD). This research showed that the ZrO₂ coatings were regularly grown on Ag-based tape substrates and coating thickness increased with increasing number of dipping. It was found that ceramic oxides formed at temperature range 450 and 550°C. The final coating thickness changed between 6 and 8μm after annealing process. Resistance of insulation measured from surface and edge regions of the coatings were 14.06 and 13.95MΩ, respectively. Critical current (I _c) of ZrO₂/AgMg/Bi-2212 coils was found to be 110.9A at 4.2K using the 10^-4V/m criterion and in a background magnetic field of 19.2T.