Er/sub 2/O/sub 3/-ZrO/sub 2/ insulation coatings on Ag/AgMg sheathed Bi-2212 superconducting tapes by sol-gel process

We have fabricated high temperature insulation coatings on long-length superconducting tapes and wires using a reel-to-reel solgel dip coating system for HTS/LTS coils at NHMFL. In this work, 8 mol% Er/sub 2/O/sub 3/-ZrO/sub 2/ coatings were deposited on Ag or AgMg sheathed Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub x/ (Bi-2212) superconducting tapes. The insulation solution was prepared with Zr and Er based organometallic compounds. The gel layers were transformed to amorphous layers at about 300(degree)C for 30 sec. in air. The ceramic oxide coatings were subsequently formed at 600 (degree)C for 60 sec. in air. The coatings on Ag/AgMg sheathed Bi-2212 tapes were finally densified by annealing at 862 (degree)C for 12 h under oxygen gas flow. These coatings were characterized by means of ESEM, DTA, and XRD. Dielectric constant, breakdown voltage and resistance values of the coatings were measured using a standard multimeter and power supply. ESEM revealed that surface morphology of the coatings is mosaic structure. XRD and DTA studies show that cubic phases formed at between 450(degree)C and 600(degree)C. Dielectric constant, high voltage breakdown and resistance values of the insulations were found to be 20, 1096 V at 1.5 mA and 14 M-Ohms, respectively.