  The thermal conductivity study on the pyrochlore structured ceramics is
important for utilization of these materials as an inert matrix fuel,
electrolytes for oxide fuel cell and thermal barrier coating. The impact of
porosity, structural defects and boundary scattering on thermal properties of
the nanocrystalline Gd2Ti2O7 fabricated by spark plasma sintering followed by
high energy ball milling has been investigated. The thermal conductivity has
been measured in the temperature range from room temperature to 900 C using
laser flash apparatus (LFA), and results were discussed by including several
phenomena contributing to the thermal transmission in nc-pyrochlore in support
of the scattering mechanism. A systematic decrease in thermal conductivity with
reducing grain size can be understood by the phonon-pore scattering phenomenon.
Furthermore, dominate of the boundary scattering on the thermal transmission
with the increasing temperature is also observed. The experimentally determined
values of thermal conductivity are compatible with the thermal insulation
requirements for thermal barrier coating (TBC) applications
