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 °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 t^1/3 (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 t^1/3. The changes in the rate can be represented by the changes of the D_LΓ value (D_L, diffusivity in liquid and Γ, Gibbs—Thomson coefficient) using the Ostwald ripening theory; i.e., the value is made lower by platinum-doping and higher by alumina-doping.