Synthesis of Pyrochlore in the System of Ca-Ce-Hf-Ti-O

Pyrochlore was known as one of the most promising materials for the immobilization of radioactive actinide. This study includes the synthesis, phase relation and characteristics of pyrochlores (CaCeH=0.2, 0.6, 1.0, 1.4, 1.8, 2.0) in the system of Ca-Ce-Hf-Ti-O. The samples were prepared from high purity of starting materials under the pressure of 400kg/cm at room temperature, and were sintered at 1200∼1 The synthesized samples were analyzed and identified with XRD. The optimal formation conditions of pyrochlores were at 1300∼150 under atmosphere with batch compositions. During synthesis, pyrochlore, perovskite and oxide were formed. The characteristics of this system is that parameter of pyrochlore was increased with the content of hafnium. This phenomenon was due to the difference of ionic size between hafnium and titanium in six coordinated site.