CRITICAL CURRENT-DENSITY AND MECHANICAL STRENGTH OF YBA2CU3O7-DELTA SUPERCONDUCTING COMPOSITES CONTAINING ZR, AG AND Y2BACUO5 DISPERSIONS BY MELT-PROCESSING

The high-T(c) YBa2Cu3O7-delta composite superconductors containing Zr, Ag and Y2BaCuO5 have been fabricated by melt processing. Both the critical current density J(c)M and the flexural strength sigma(max) of these samples were measured. The value of J(c)M increased initially for all inclusions added. The microstructure analyses revealed that Y2BaCuO5, Ag and BaZrO3 were finely dispersed in the matrix. We believe that the fine dispersion of these inclusions is most likely responsible for an increase in J(c)M. The largest value of J(c)M we obtained is 64 800 A/cm2 on the sample containing 50 mol.% Y2BaCuO5. In contrast, the value of sigma(max) was limited below 60 MPa due to the presence of mechanically weak grain boundaries. The addition of Ag to YBa2Cu3O7-delta was effective in increasing both sigma(max) and J(c)M.