Compositions and Particle Sizes of (RE)Ba2Cu3O7-X Superconductor Powders Synthesized by the Solution Combustion Technique

Abstract

Superconducting compounds (RE) Ba2Cu3O7-x (RE = rare earth such as Y, Er, Sm and Nd) can be exploited in various industrial applications such as cables, electric motors and energy storage systems. The project aimed at synthesizing fine-particle YBa2Cu3O7-x, ErBa2Cu3O7-x, SmBa2Cu3O7-x and NdBa2Cu3O7-x, powders with compositions suitable for the applications. Solution combustion technique was employed in the synthesis, using urea as fuel. Compositional analysis obtained from x-ray diffraction indicated that the as-synthesized powders contained the desired (RE)Ba2Cu3O7-x (RE123) superconducting phase and impurities, including (RE)2BaCuO5 (RE211), BaCO3 and Ba(NO3)2. However, majority of the impurities were eliminated when the powders were calcined at 900°C. Only (RE)Ba2Cu3O7-x (RE123) and (RE)2BaCuO5 (RE211) phases remained after calcination. Results from scanning electron microscope showed that the as-synthesized powders obtained from the solution combustion technique had relatively small particles with average particle size of 0.67 micrometers, while the calcined powders exhibited coarsening effects with average particle size of 4.4 micrometers.