ON THE INFLUENCE OF K2CO3 ADDITIVES IN OBTAINING HTSC MATERIALS OF THE YBCO SYSTEM

The concentration dependence of the transition temperature T-c and mic rostructure has been studied in the high-T-c compounds Y1-0-2xBa2-0.2x KxCu3O7-y,Y1Ba2Cu3.5-xKxO7-y, Y1Ba2-xCu3KxO7-y, where x = 0-1.50. Only traces of K (1 x 10(-2) wt%) were observed in all samples after the f inal baking and no proof could be found for alkali metal cations parti cipating in the Perovskite crystal cell. Between x = 0.40-0.75 a homog eneous grain-size ceramic structure was observed. This behaviour permi ts the obtaining of monophase Y1Ba2Cu3Oy with values of T-c = 93.6 K a nd Delta T = 1.5 K using simplified technological process and baking i n air atmosphere.