Effect of particle size and particle size distribution on physical characteristics, morphology and crystal structure of explosively compacted high-Tc superconductors

A superconductor, of composition Y(Ba,K,Na)2Cu3Ox/Fy and a composite, of composition Y(Ba,K,Na)2Cu3Ox/Fy+Ag, with changing K, Na and F content, but a constant silver content (Ag=10 mass per cent) was prepared using a single heat treatment. The resulting material was ground in a corundum lined mill, separated to particle size fractions of 0-40 μm, 0-63 μm and 63-900 μm and explosively compacted, using an explosive pressure of 104 MPa and a subsequent heat treatment. Best results were obtained with the 63-900 μm fraction of composition Y(Ba1,95K0,01)Cu3OxF0,05/Ag: porosity <0.01 cm3/g and current density 2800 A/cm2 at 77 K