Highly porous yttrium aluminium garnet (YAG) particles synthesised by a gel supported precipitation (GSP) process

Abstract

Yttrium aluminium garnet (YAG) has been successfully manufactured by a liquid to particle conversion process, usually known as the gel supported precipitation (GSP) method. The conversion involves a localised ammonia precipitation, which was successfully achieved without loss of stoichiometry, with respect to yttrium and aluminium, in the precipitation step. The resulting particles are in the form of near spherical beads, whose compaction behaviour exhibits a marked dependence on the Yttrium and Aluminium concentration in the feed solution. The pellet densities of ca. 90% of the theoretical density are ideal for minor actinide transmutation targets, where release of He produced by their irradiation in a nuclear reactor is necessary. Furthermore, the YAG particles produced by the GSP route are sufficiently porous, to enable their infiltration by an actinide nitrate solution. Tests using cerium nitrate solutions to simulate the minor actinide solutions have shown that up to 65 wt% of CeO2 can be incorporated in YAG using this novel fabrication route.