Peculiarities of High-Pressure Oxygenation of MT-YBCO

The oxygenation under the high 16 MPa oxygen pressure allows reducing the duration of oxygenation and in the case of thin-walled MT-YBCO ceramics (with drilled holes) leads to a decrease of the amount of macrocracks in the structure and to an increase in critical current density in the ab-planes. An increase in the twin density enhances the critical current density in the ab-planes of the Y123 textured structure of MT-YBCO. After oxygenation under different conditions the MT-YBCO ceramics produced from a mixture of Y123 with Y211 demonstrated a critical current density in magnetic fields above 2 T at 77 K higher in the ab-planes and lower in the perpendicular c-direction than the MT-YBCO produced from Y123 and Y₂O₃. Mechanical properties (hardness, fracture toughness, Young modulus) have been estimated for various types of MT-YBCO oxygenated under different conditions. Both traditional and thin-walled ceramics have a higher microhardness after oxygenation under high 16 MPa oxygen pressure.