Synthesis, Phase and Structural Analysis of Compounds in the System Gd_(2-x)Nd_xZr2O7 (0.0 ≤ x ≤ 2.0)

摘要

A series of compounds with the general formula Gd_(2-x)Nd_xZr2O7 (0.0 ≤ x ≤ 2.0) was synthesized by high-temperature solid state method and characterized by powder X-ray diffraction. Trivalent neodymium was used as the surrogate for americium with three valences, an actinide found in radioactive nuclear wastes. The X-ray diffraction patterns show that the whole system of Gd_(2-x)Nd_xZr2O7 (0.0 ≤ x ≤ 2.0) consistently possesses the pyrochlore structure. In order to get the accurate data of structural changes of zirconate pyrochlores incorporating Am~(3+), the Rietveld structural refinement method was employed to calculate the crystal cell parameters of zirconate pyrochlores. The calculated results indicated that the value of x in the system Gd_(2-x)Nd_xZr2O7 (0.0 ≤ x ≤ 2.0) and the crystal cell parameter a accord with a = 10.52696 + 0.07036 x, x and the volume of crystal cell V follow the relation of V= 1166.45459 + 23.72163 x.