A comparison of the extended x-ray absorption fine structure of nanocrystalline ZrO2 prepared by high-energy ball milling and other methods

We report the results of an extended x-ray absorption fine structure (EXAFS) study of a sample of ZrO2 prepared by high-energy ball milling. X-ray diffraction showed that the sample contained nanocrystals that were predominantly monoclinic with a particle size of 15 nm. The EXAFS for the sample was strongly attenuated in comparison to that for bulk monoclinic ZrO2. This has been interpreted as the ball-milled sample containing a large level of disorder whose possible origins are discussed. In contrast, our previous EXAFS studies of nanocrystalline oxides prepared by sol-gel methods have shown that these samples contain well-ordered crystallites with grain boundaries similar to those in bulk materials. It is concluded that ball-milled samples are very different from oxide nanocrystals produced by other techniques.