SUN Xi 1, MA Jingtao 2, DENG Changsheng 2, ZHAO Xingyu 2, HAO Shaochang 2, LIU Bing 2
(1. Nuclear fuel and material research department, Central research institute of state power investment corporation, Beijing 102209, China; 2. State Key Laboratory of New Ceramics and Fine Processing, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China)
Abstract: UO2-UC composite ceramic microspheres were prepared by using the combination of internal gelation and carbothermal reduction process. The effects of the type of carbon black on dispersion stability, viscosity of the broth and microstructure of the UO2-UC sintered microspheres were studied. It was observed that the UO2-UC ceramic microspheres prepared with carbon black having particle size of less than 1 μm possessed obviously small pores. The conversion from UO2 to UC during the heat treatment process was studied by using DSC-TG and XRD analytic techniques, revealing that UC could be formed through carbothermal reduction reaction at temperatures of ≥1600 ℃. UO2-UC ceramic microspheres with high sphericity and high crushing strength were obtained by using the optimized carbon black at 1680 ℃ in flowing Ar.
Key words: UO2-UC ceramic microspheres, carbon black, sintering temperature, carbothermic reduction