Influence of residual phases on the properties of YBa/sub 2/Cu/sub 2/O/sub 7-x/

The partial melting in YBaCuO incompletely synthesised powders occurring at temperatures below the peritectic decomposition of the 123 (i.e. YBa/sub 2/Cu/sub 3/O/sub 7-x/) compounds is related to the presence of residual phases. Our results showed that the final ceramic has a high porosity, which is independent of the temperature of sintering, the double grain size distribution and two transition temperatures up to the sintering temperature (940/spl deg/C) as a consequence of a higher content of the residual carbonate. Sintering at a higher temperature improved the superconducting properties of our ceramics. This progress is connected with the cracking of large grain ceramics and with the decomposition of carbonate BaCO/sub 3/.<
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