We have investigated the homogeneity of sol‐gel derived YBa2Cu307‐s from the
solution phase to the final product using transmission electron microscopy
(TEM), x‐ray diffraction (XRD), and Energy Dispersive X‐ray (EDX) lateral
mapping techniques. The starting solutions contain stoichiometric amounts of
the metal 2‐(2‐methoxyethoxy)ethoxide components in
2‐(2‐methoxyethoxy)ethanol and appear to be homogeneous by TEM with a
uniform distribution of particles having an average size of less than 40 â.
Through elemental mapping we see elemental segregation in the high
temperature (950 °C) products, which are orthorhombic by XRD. In elemental
maps of gel samples fired to 700 °C, which are tetragonal by XRD, we also
see elemental inhomogeneity within particles and phase zoning in maps of
products from finely ground gels. A comparison of elemental maps and x‐ray
diffraction patterns of the products from gel processing and conventional
solid state processing is made.