Phase and microstructure evolution of 0.2SiO2/Zr1-xNdxSiO4-x/2 (0 ≤ x ≤ 0.1) ceramics

Zircon (ZrSiO 4 ) ceramics were widely used in the field of nuclear waste immobilization because of their excellent properties. However, the SiO 2 /ZrSiO 4 ceramics were usually obtained in the preparation of ZrSiO 4 . The actinides immobilization behavior of SiO 2 /ZrSiO 4 ceramics is unclear. Herein, Nd-doped 0.2SiO 2 /Zr 1- x Nd x SiO 4- x /2 (0≤ x  ​≤ ​0.1) ceramics were fabricated and the effects of Nd-doping and sintering temperature on their phase and microstructure evolution were investigated. The obtained ceramics were characterized by XRD , SEM, BSE and EDS . Results show that 0.2SiO 2 /Zr 1- x Nd x SiO 4- x /2 ceramics with 0≤ x  ​< ​0.04 are ZrSiO 4 phase; while with 0.04≤ x  ​≤ ​0.1 are coexistence of ZrSiO 4 and Nd 2 Si 2 O 7 phases. The solubility limit of Nd 3+ in 0.2SiO 2 /ZrSiO 4 is about 4 ​at%. The lattice volume of ZrSiO 4 increased with increasing Nd-doped content and sintering temperature. Furthermore, higher Nd-doped content and sintering temperature are beneficial to the densification of the obtained ceramics. The results demonstrate that the 0.2SiO 2 /ZrSiO 4 ceramics can be employed as waste form materials to immobilize trivalent actinides.