Preparation and thermophysical properties of Sm₂(Ce _0.3Zr_0.7)₂O₇ ceramic

A ceramic Sm₂(Zr_0.7Ce_0.7) ₂O₇ was synthesized by solid reaction and the microstructure and thermophysical properties of this ceramic were examined. The linear thermal expansion coefficient (CTE) of the sample was determined with a high temperature dilaometry operating in a temperature range between 100°C and 1200°C at a heating rate of 5°C /min in argon atmosphere. The vacancies constituting groups or pairs have no effect on phonon scattering, and the effect of increasing of atomic weight and crystal lattice aberrance on phonon scattering is far from that of vacancies. The higher thermal conductivity of the ceramic can be attributed to the crystal structure transformation from pyrochlore to fluorite.