Neutron irradiation-induced structural evolution and defect-related phase stability in ZrO 2 –Fe ceramics

In this study, neutron-irradiation-induced structural changes in ZrO 2 –Fe samples containing 4[Formula: see text]wt.% Fe were investigated by neutron diffraction. Rietveld refinement showed that the initial sample consisted mainly of monoclinic ZrO 2 with space group P 1 [Formula: see text] 1 (No. 14), together with a minor [Formula: see text]-Zr 4 Fe 2 O phase with space group [Formula: see text]-3m (No. 227). After neutron irradiation in the fluence range from [Formula: see text] [Formula: see text]n/cm 2 to [Formula: see text] [Formula: see text]n/cm 2 , the reflections of the secondary phase became strongly weakened, while the monoclinic ZrO 2 matrix remained structurally stable. The irradiation-induced structural evolution was reflected in the non-monotonic changes of the lattice parameters and unit-cell volume of monoclinic ZrO 2 . In addition, the ZrO 7 polyhedral distortion increased from 3.8% in the initial sample to 6.7% at the highest fluence, indicating an average long-range oxygen-sublattice response to neutron irradiation. The initial lattice expansion and subsequent contraction at higher fluences are consistent with irradiation-induced defect redistribution.