METHOD OF PREPARING BISMUTH-LEAD-STRONTIUM-CALCIUM CUPRATE MONOCRYSTALS Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: method involves heating of charge of the following composition, mol. m.: Bi₂O₃ 19,85-20,62; PbO 4.41-4.58; SrCO₃ 31,75-32,24; Ca-CO₃ 13,56-13,82; and CuO - the rest. Then melt is homogenized and crystallized at cooling at the range 880-892 C on the platinum crystalloholder. Crystallization is finished 3-4 C after of its onset, cooling rate at this range is 0.03-0.06 degree/h. Then crystals were separated from melt by stretching following by centrifugation at the rate 130-160 rev/min. Prepared crystals have phases 2:2:1:2 with transient width ΔT_c up to 2K and critical current density up to 1·10⁴А/cm² Product is used in high-temperature superconductors. EFFECT: improved method of monocrystals preparing.