Characterization and phase stability of pyrochlore (Nd1−xCex)2Zr2O7+y (x = 0–1)

Powders of (Nd 1− x Ce x ) 2 Zr 2 O 7+ y ( x   =   0–1) with pyrochlore structure were prepared by sol-spray pyrolysis and subsequent graphite reduction at 1200   °C. The effects of cerium content on crystal structure, phase stability and microstructure of the (Nd 1− x Ce x ) 2 Zr 2 O 7+ y ( x   =   0–1) inert matrix materials were studied. XRD and Raman results presented that all samples were in a single pyrochlore phase. XPS results indicated the cerium was in a single oxidation state of +4. After sintering at 1500   °C for 24   h in air, the sample of x   =   1 underwent a phase segregation to Zr 1− x Ce x O 2 solid solutions of tetragonal, metastable tetragonal and cubic phases, the sample of x   =   0.9 contained a few tetragonal phase in addition to fluorite phase, the samples of x   =   0.5–0.8 had a single phase fluorite structure, the samples of x   =   0–0.4 maintained the pyrochlore structure.