Mass transport and chemical demixing of Y-Ba-Cu-O compounds during sintering in temperature gradients

A thin cylindrical powder compact (3-mm diameter by 20-mm) with a nominal composition of YBa/sub 2/Cu/sub 3/O/sub x/ was sintered in a static temperature gradient of 250C/mm in air for 12 h. The temperature at the hot end of the sample was maintained at 9400+-50C. Considerable mass transport and chemical demixing occurred along the length of the sample. The results are consistent with the formation of a liquid phase at the hot end of the sample, transport of the liquid down the temperature gradient, and the formation of different eutectic compositions along the length of the sample. The implications for processing high-T/sub c/ superconductors in the system Y-Ba-Cu-O are discussed