Research on fabrication of ceramic breeding materials by different techniques

Full text of publication follows: Lithium based oxide ceramics, such as Li2TiO3, Li2ZrO3, γ-LiAlO2, and Li4SiO4 have been proposed as tritium breeding materials in the deuterium-tritium (D-T) fusion reactor. For different purposes, the breeding materials might be in different forms such as pebble, pellet, ring or even tubes. This presentation will summarize the research work on the preparation of lithium ceramics with different forms by various techniques in the Shanghai Institute of Ceramics, Chinese Academy of Sciences. High quality of ceramic powders has been considered as one of the most important factors influence the performance of the breeding materials. Li2TiO3, γ-LiAlO2, and Li4SiO4 powders with nano-scaled particle size were synthesized respectively by solid state reaction, sol-gel and combustion techniques. The obtained powders exhibited high reactivity at moderate temperatures. A newly developed sol-gel method using water as the reaction medium and LiNO3 and Ti(C6H607)2 as raw materials was applied to synthesize Li2TiO3 with 40 nm in diameter at the temperature as low as 500 deg. C. Li2TiO3 pebbles were successfully fabricated by different ways, e.g., sol-gel method, direct wet process and extrusion-spherunization- sintering method, the size of the pebbles could be easily controlled in the range of 0.5-2 mm, with relative density flexible and controllable. The Li4SiO4 pebbles were prepared by gel-precipitation technology and extrusion-spherunization- sintering method. The pebbles exhibited high sphericity, uniform distribution in size. γ-LiAlO2 pellets and tubes were prepared by isostatic pressing and extrusion processes, the tubes are perfect in form with specially designed microstructures. The mechanical strength and thermal expansion coefficient were favorable. (authors)