DOPING EFFECTS ON COARSENING OF Y2BACUO5 PHASE IN LIQUID

The coarsening rate of Y2BaCuO5 (211) phase in liquid was investigated by observations of samples which were, held at 1070-degrees-C for different holding times. The 211 phase formed rod-like shapes, and the diameters increased with the increase in the holding time. The average diameter increased in proportion to t1/3 (t, holding time). This means that coarsening can be explained by the modified Ostwald ripening theory. Platinum-doping suppressed the coarsening rate and alumina-doping promoted it. However, both coarsening rates were also proportional to t1/3. The changes in the rate can be represented by the changes of the D(L)GAMMA value (D(L), diffusivity in liquid and GAMMA, Gibbs-Thomson coefficient) using the Ostwald ripening theory; i.e., the value is made lower by platinum-doping and higher by alumina-doping.