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Preparation of YBa2Cu3O7-x  Superconducting Films: Influence of the Chemical Composition on the Sintering.

E. Benavidez and N. Quaranta (*)
Desarrollo y Tecnología de Materiales, FRSN, UTN, San Nicolás, Argentina 

C. J. R. González Oliver (**)
Centro Atómico Bariloche, CNEA, Bariloche, Argentina 

R. Caruso (**) and O. De Sanctis
Laboratorio de Materiales Cerámicos, FCEIyA, UNR-IFIR, Rosario, Argentina

 and A. Frattini
Departamento de Física y Química, FCByF, UNR, Rosario, Argentina

 

(*) CICPBA researcher and Member of the Executive Committee of the International Ceramic Federation.

(**) CONICET

 


ABSTRACT:

The influence of the cationic ratio Y:Ba:Cu on the kinetics of densification of the YBa2Cu3O7-x (YBCO) superconductor ceramic was studied. The powders were prepared from organic precursors and the nominal compositions were: (A) stoichiometric composition YBa2Cu3O7-x , (B) composition on the tie line that joining YBa2Cu3O7-x - BaCuO2 phases, and (C) composition in the triangle YBa2Cu3O7-x - Y2BaCuO5 - CuO. The phases present in these powders heated to 890°C were detected by XRD, while the ratio Y:Ba:Cu was measured by Neutronic Activation Analysis (NAA). The reactions between 900°C and 1070°C, under O2 atmosphere, were determinated by DTA at a heating rate of 10°C/min. Compacts of different powders were obtained by uniaxial pressing and then were studied by dilatometric runnings under similar conditions that established in DTA measurements. On the dilatometric curves were applied different sintering models, obtaining the validity range and activation energies corresponding to the different densification mechanisms that operating in the initial and the intermediate stage of sintering.