Ce 0.8 Sm 0.2 O 1.9 (SDC)-xMgO (x = 0, 5, 10, 15, and 20 mol%) composite powders were synthesized by a sol-gel method and then densified by spark plasma sintering (SPS) to investigate the effects of MgO additions on the electrical conduction behavior of CeO 2 -based ceramics. The microstructure and electrical performances of the SDC-MgO composite ceramics were characterized and measured by XRD , SEM, TEM, EDS and EIS . Results show that the second phase of MgO segregates at the grain boundaries of SDC when its content is higher than 5 mol% in the ceramics. The SPS process accelerates the formation of MgO lamellar grains with incomplete crystallization. As the MgO content rises from 0 to 20 mol%, the grain boundary and total electrical conductivities first increase and then decrease, and the SDC-5%MgO sample exhibits the highest total conductivity, i.e., 2.76 × 10 −2 S/cm at 650 ° C, which is 9.65% higher than that of pure SDC.
Jinhui Tan,Rongxia Huang,Hua-Tay Lin,Malin Liu,Bing Liu,Rongzheng Liu
A novel gel-casting process for fabrication of the fully ceramic microencapsulated (FCM) fuel with high TRISO particles loading capacity was proposed. In the gel-casting process, silicon carbide (SiC) ceramic was used as matrix, and low toxic N-methylol acrylamide was used as organic monomer with appropriate proportion of cross-linking agent, dispersant , and initiator to achieve the strength of green bodies. FCM fuel pellets with high TRISO particles loading capacity were successfully prepared by SPS process. By using the gel-casting method, the volume fraction of TRISO particles could reach 57%, and the average distance between TRISO particles in a plane was 52.4 μm, which could avoid TRISO particles damage introduced by direct contact between the particles. The structure of SiC matrix was dense and complete, and there was a coherent contact between the matrix and TRISO particles, which ensured the performance and reliability of FCM fuel.
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