Determining europium compositional fluctuations in partially stabilized zirconia nanopowders: a non-line-broadening-based method

Acta Crystallogr B Struct Sci Cryst Eng Mater. 2016 Feb;72(Pt 1):29-38. doi: 10.1107/S2052520615021083. Epub 2016 Jan 23.

Abstract

A method is reported for assessing the compositional fluctuations in a ceramic sample, based only on the determination of the crystalline lattice parameters. Pure tetragonal phase partially stabilized zirconia powders are synthesized through the co-precipitation method by incorporating 4% Eu(3+). The powder is subjected to compression cycles to promote the tetragonal-to-monoclinic transformation. The Rietveld analysis of the X-ray powder diffraction patterns, recorded after each compression cycle, gives information about the lattice parameters and monoclinic phase content. The determination of europium content in the residual tetragonal phase is accomplished considering the unit cell volume of t-ZrO2 using Vegard's law. Using this information the compositional fluctuations over the sample were determined by considering two possible distributions of lanthanide ion content in the powders: a Gaussian and a Log-normal one. It was found that the Gaussian distribution better fits the experimental data. It was eventually demonstrated that these results are physically meaningful.

Keywords: X-ray diffraction; compositional fluctuations; europium; tetragonal zirconia; zirconia.