A New Method on High Temperature Superconductor Material Synthesis by Combination of MCA and SHS

摘要

The combination of mechano-chemical activation and self-propagating high-temperature synthesis (SHS) has been widened the possibilities for both methods. For YBCO systems the investigation showed that a short-term mechano-chemical activation of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparing ultra fine high-temperature superconductor of YBCO composed with a grain size of d < 1 μm was developed. The specific feature of the technique was formed with the YBa_2Cu_3O_(7-δ) crystalline lattice directly from the X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray analysis and magnetic studies of ultra-fine high temperature superconductor (HTS) were carried out. Dimension effects associated with the microstructure peculiarities were revealed. A considerable enhancement of inter-grain critical currents was found to take place in the ultra-fine samples investigated.