Tetragonal zirconia nanocrystals

Joo J et al (2003) Multigram scale synthesis and characterization of monodisperse tetragonal zirconia nanocrystals. J Am Chem Soc 125 6553-6557... 

As above-mentioned, the oxidation of ZrC is diffusion controlled. The oxygen diffusion should be prompted in presence of carbon vacancies, especially ordered carbon vacancies. It has been reported that the starting temperature of oxidation should be at 300 °C for stoichiometric or nearly stoichiometric ZrC, independent of oxygen pressures (Shimada Ishii, 1990). At the initial stage of oxidation, a thin layer of oxycarbide can be observed to form. At an elevated temperature, the oxycarbide layer can be transformed to an amorphous one, from which the cubic/tetragonal zirconia nanocrystals can be developed. To date this process is still not clear. Though the formation of the oxycarbide layer can be proposed by the composition analysis, the structure is not completely identified. Many authors proposed that the structure of the formed oxycarbide should be similar to rocksalt structured ZrC with a small... 

Another noteworthy effort at nanocomposite fabrication applied ceramic nanoparticles to a ceramic material to enhance osteoconductivity and mechanical performance. Nawa et al. [49] developed a ceria-stabiHzed tetragonal zirconia polycrystal (Ce-TZP) ceramic and incorporated alumina (AI2O3) nanocrystals into it via wet chemistry methods for load-bearing bone applications. Further studies of this material investigated its ability to induce apatite formation [50], in vivo biocompatibility, and resistance to wear [10] with favorable results. 

Figure C2.17.4. Transmission electron micrograph of a field of Zr02 (tetragonal) nanocrystals. Lower-resolution electron microscopy is useful for characterizing tire size distribution of a collection of nanocrystals. This image is an example of a typical particle field used for sizing puriDoses. Here, tire nanocrystalline zirconia has an average diameter of 3.6 nm witli a polydispersity of only 5% 1801.

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