Fabrication of Li4SiO4 ceramic pebbles with uniform grain size and high mechanical strength by gel-casting

Abstract Lithium orthosilicate pebbles are one of the ceramic tritium breeder materials destined for the Test Blanket Modules (TBM) of the International Thermonuclear Experimental Reactor (ITER). Li 4 SiO 4 ceramic pebbles with high phase purity and high mechanical strength were prepared by gel-casting hydrothermally synthesized precursor powders. Thermal and XRD analyses indicate that the phase formation temperature of Li 4 SiO 4 synthesized by gel-casting is about 100 °C lower than for the solid-state reaction method. Li 4 SiO 4 ceramic pebbles with good sphericity, high phase purity, high crush load (a.v 35.6 N), uniform microstructure and high porosity were obtained by gel-casting process at temperature as low as 700 °C with good potential as tritium breeding materials for blankets.