Rapid synthesis of Nd-doped Y3Fe5O12 garnet waste forms by microwave sintering

The garnet structure is a promising solid material for nuclear waste because it can contain all kinds of actinides. Yttrium iron garnet Y 3 Fe 5 O 12 (YIG) is the model component of this kind of substitute. In this study, Nd-doped YIG ceramic samples were prepared by microwave sintering at different sintering temperatures (1100 °C, 1200 °C, and 1300 °C) for different sintering time (0.5 h, 2 h, 4 h, and 6 h). The effects of synthesis temperature and sintering time on the solubility and microstructure of Y 3-x Nd x Fe 5 O 12 (0 ≤ x ≤ 3.0) were evaluated. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and backscattering scanning electron microscopy (EBSD) results show that single phase garnet structure can be synthesized and enhanced solubility of Nd in YIG was found at higher temperatures. The solubility of Nd in garnet is 50 mol% (x = 1.5) and 60 mol% (x = 1.8) at 1200 °C and 1300 °C, respectively. There is no significant dependence of the solubility on sintering time. The SEM analysis and Archimedes drainage test show that the relative density of Y 1.2 Nd 1.8 Fe 5 O 12 ceramics is 88.15% and 99.94% at 0.5 h and 6 h, respectively, indicating dense YIG could be obtained with a relatively long sintering time. The results show that microwave sintering can rapidly and efficiently synthesize the YIG ceramic samples.