Jl. Sobolik et al., EFFECT OF PARTICLE-SIZE ON BINARY REACTIONS COMMON TO THE Y-BA-CU-O SYSTEM, Journal of the American Ceramic Society, 77(10), 1994, pp. 2738-2746
A systematic study has been conducted to determine the effects of part
icle size on the reaction paths leading to binary phases in the Y-Ba-C
u-O system. Using dynamic X-ray diffraction (DXRD), three binary react
ion sets with stoichiometries equal to that present in the Y-Ba-Cu hig
h-T(c) superconductor and having two different particle sizes (nanomet
ers and micrometers) were reacted in both air and helium environments.
Results indicate that the absence of oxygen and carbon dioxide leads
to lower reaction temperatures and to different products in the Y-Cu a
nd Ba-Cu binaries. Particle size comparisons show not only a higher re
activity in the nanometer system, but also different products due to t
he diffusion limitations in the micrometer system. Comparisons between
the binary and ternary reactivities point to the Ba-Cu binary as the
most critical reaction system for assuring high-quality HTSC.