Self-propagating chemical furnace synthesis of nanograin Gd₂Zr₂O₇ ceramic and its aqueous durability

Highlights: • Gd₂Zr₂O₇ nanograin ceramic was rapidly synthesized by SCF/QP process. • The SCF technique exhibits very high heating rate (>1600 °C). • The normalized leaching rates of Gd and Zr are as low as 5.4 × 10⁻⁶ and 8.2 × 10⁻⁷ g m⁻² d⁻¹. - Abstract: Gd₂Zr₂O₇ ceramic is recognized as an ideal matrice for the immobilization of high-level radioactive waste. In this report, the single Gd₂Zr₂O₇ nanograin ceramic was rapidly synthesized by self-propagating chemical furnace synthesis plus quick pressing (SCF/QP) using Gd₂O₃ and ZrO₂ with nano-scale particle size as the raw materials. The results demonstrate Gd₂Zr₂O₇ nanograin ceramic with an average grain size of 84 nm was successfully obtained under the ultra-high heating rate. The Gd₂Zr₂O₇ ceramic shows reasonable high Vickers hardness of 11.4 GPa and bulk density of 6.54 g/cm³. The aqueous durability was also evaluated. The LR_Gd and LR_Zr values of Gd₂Zr₂O₇ sample were as low as 5.4 × 10⁻⁶ and 8.2 × 10⁻⁷ g m⁻² d⁻¹ after 42 days leaching.