Amorphous and nanocrystalline ZrO2 center dot Y2O3 (15%) studied by extended X-ray absorption fine structure

Chemical coprecipitated amorphous and nanocrystalline ZrO2.Y2O3 (15%) was S tudied by Powder X-ray diffraction(XRD) and extended X-ray absorption fine structure(EXAFS). XRD result shows that the sample is an amorphous phase an nealed below 300 degreesC; and it crystallizes into cubic nanocrystalline z irconia at 500 degreesC. EXAFS analysis indicates that the coordination num ber and bond length of Zr-O shell has not changed when transforming from am orphous into nanocrystalline. This suggests that at 300 degreesC,it has for med the same nearest-neighbor local structure as at 900 degreesC. For Zr-Zr (Y) shell, with the reducing of grain size, the coordination number decreas es obviously: the bond length is shorter and the disorder becomes larger. T his result suggests that the grain size effect is much stronger for more di stant coordination shell (Zr-Zr) than for the first nearest-neighbor shell( Zr-O).