Preparation of MgO-Nd2Zr2O7 composite ceramics used for inert matrix fuel by one-step sintering method

Abstract

MgO-Nd2Zr2O7 composite ceramic is a promising candidate as an inert matrix material for the transmutation of Pu and minor actinide. In this work, the MgO-Nd2Zr2O7 composite ceramics (hereafter M-NZO) with 30–70 wt% mass percent of MgO were successfully prepared at 1500 °C for 24 h via direct solid-state reaction one-step method. This method achieved the integration of Nd2Zr2O7 pyrochlore synthesis and M-NZO composites sintering, which shows a significant improvement in the simplification of the preparation process than the traditional two-step method. The structural properties and compactness of the as-prepared composite ceramics were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM). It was confirmed that the as-prepared M-NZO ceramics are composed of only crystalline MgO and Nd2Zr2O7 phases, and the mass fractions of two phase are almost the same as the designed nominal chemical composition. The composite ceramics showed remarkable densification and the relative density is higher than 98.2%.