Self-propagating high-temperature synthesis of Y2Ti2O7 pyrochlore and its aqueous durability

Abstract

In this study, highly densified Y2Ti2O7 pyrochlore waste forms were readily prepared within 5 min by self-propagating high-temperature synthesis plus quick pressing (SHS/QP). Fe2O3 was employed as the oxidant with Ti as the reductant. The as-prepared sample exhibits an analogous self-encapsulated morphology with Y2Ti2O7 core and Fe cladding. The synthesized pyrochlore-based waste form possesses high density of 5.35 g/cm3 and Vickers hardness of 11.5 ± 0.2 GPa, as well as excellent aqueous durability. The 28 days normalized leaching rates of Y, Ti and Fe are as low as 1.07 × 10−6, 6.63 × 10−5 and 1.42 × 10−5 g m−2 d−1.