Solubility of Sr2+ in the Gd2Zr2O7 ceramics via appropriate occupation designs

Free occupying mechanism of simulated tetravalent waste ions in Gd2Zr2O7 and performance evaluation of the waste forms

“…With the addition of CeO 2 , the vibration mode of A 1g (∼540 cm −1 ) disappeared, which was a typical pyrochlore Raman peak 31 . Among the samples with doping content of 10 and 20 wt.%, only three Raman scattering peaks, E g (∼310 cm −1 ), F 2g (∼400 cm −1 ), and F 2g (∼610 cm −1 ), were observed.…”

Preparation and Density Functional Theory Studies of Aluminosilicate-Based Ceramic Solidified Products for Sr Immobilization

“…At the atomic scale, radioactive elements can enter the lattice structure of ceramic matrix materials, thereby forming a safer immobilization barrier than in glass [18]. At present, various ceramic materials, such as phosphates, aluminosilicates, titanates, zirconates, and vanadates [7,[17][18][19][20], have been extensively studied as matrices for immobilizing radioactive wastes through methods, such as cold pressing/sintering, microwave sintering, and spark plasma sintering [21][22][23][24].…”

Experimentally and Theoretically Revealing the Co-Doping Effects of Ce–Sr in Gd2Zr2O7

“…Gd 2 Zr 2 O 7 pyrochlore is such a material that meets the requirements for deep geological disposal. Gd 2 Zr 2 O 7 pyrochlore exhibits an A 2 B 2 O 7 stoichiometry, where A is a trivalent rare earth ion at eight-coordinated sites located within a distorted cubic polyhedron and can be substituted by significant amounts of divalent, trivalent, and tetravalent actinides with 0.086–0.15 nm. − Generally, the phase stability is mainly governed by the ionic radius ratio of the cations ( r A / r B ) . Under normal pressure, the ordered pyrochlore structure with the Fd 3̅ m space group can form in the range of 1.46 ≤ r A / r B ≤ 1.78; otherwise, a disordered defect fluorite is formed …”