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

The disposal of strontium (Sr) from nuclear reactions has been a great challenge in the nuclear industry. Based on four kinds of occupation methods, a series of SrO-doped Gd2Zr2O7 compositions with the general formula Gd2-2x/3SrxZr2O7, Gd(2)Zr(2-x/2)SrxO(7), Gd2-xSrxZr2O7-x/2 and Gd2Zr2-xSrxO7-x (0.0 <= x <= 2.0) were prepared by a high temperature sintering method solid state route. The influences of Sr substitution on the structure modifications, solid nuclear mobility, microstructure, and element distribution were studied. Our results show that the four sets of samples reach the maximum solid solubility within the range of x > 2.0, 1.5 < x <= 2.0, 1.0 < x <= 1.5, 1.0 < x <= 1.5, respectively. It was found out that the compound phase of SrZrO3 and pyrochlore appeared in all the samples. In addition, the amount of the SrZrO3 increases while the amount of the pyrochlore decrease and that of Sr2+ increases. (C) 2019 Elsevier B.V. All rights reserved.