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

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). Li4SiO4 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 Li4SiO4 synthesized by gel-casting is about 100 °C lower than for the solid-state reaction method. Li4SiO4 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.