Abstract
YBa 2 Cu 4 O 8 superconducting oxide can be synthesized through the reaction of Y 2 BaCuO 5 , BaCuO 2 , and CuO at 800°C in O 2 ambient. However, the reaction rate was much slower than that of the formation of YBa 2 Cu 4 O 8 from nitrides. Silver was found to be a reaction-rate enhancer to form YBa 2 Cu 4 O 8 through the reaction of Y 2 BaCuO 5 , BaCuO 2 , and CuO. A variety of silver-containing reactions were conducted to reveal the dependence of reaction rate on Ag content. Transmission electron microscopy observation was carried out to investigate the role which silver played in the reactions. The effect of the intermediate oxide, Ba 2 Cu 3 O 5+x , was also studied. © 1991.