AN INVESTIGATION INTO THE SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS (SHS) OF SUPERCONDUCTING CERAMICS BY THERMAL METHODS

The SHS route is based on the well-known thermite reaction, in which a strongly exothermic reaction can sustain itself and propagate in the form of a combustion wave until the reactants have been completely consumed. The successful application of the method to the synthesis of superconducting ceramics of stoichiometry RBa2Cu3Oy (R = Y, Er, Yb) is reported. The 123 phase was obtained when pellets of R2O3, BaO2 and Cu metal in the correct proportions were dropped into a heater held at 800-degrees-C in an oxygen atmosphere and left there for only 10 minutes. Thermal methods (DSC and DTA) are excellent techniques with which to investigate the dependence of the reaction on heating rate, atmosphere and starting composition.