Defects and sintering-induced diffusion processes in yttria-stabilised zirconia nanomaterials studied by positron annihilation spectroscopy
Defects and sintering-induced diffusion processes in yttria-stabilised zirconia nanomaterials studied by positron annihilation spectroscopy
Prochazka, I.; Cizek, J.; Melikhova, O.; Anwand, W.; Konstantinova, T. E.; Danilenko, I. A.
In the present work, zirconia (ZrO2) nanopowders doped with yttria (Y2O3) and chromia (Cr2O3) were prepared by a co-precipitation technique. The nanopowders were then subjected to a calcination and a successive sintering at elevated temperatures up to 1500 °C. The nanostructures in these nanomaterials were characterized by positron annihilation spectroscopy (positron lifetimes and Doppler broadening measurements) which is a non-destructive technique with a high sensitivity to atomic-scale open-volume defects. It was found that the zirconia-based nanomaterials studied contain vacancy-like defects and nano-scale pores. Diffusion processes induced in these nanomaterials by sintering were investigated also by depth sensitive positron annihilation studies using a variable energy slow positron beam. Sintering was found to cause intensive grain growth and a removal of porosity by a migration of pores from the sample interior toward its surface.
Keywords: Zirconia; Nanopowders; Sintering; Porosity; Positron annihilation
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Diffusion Foundations 1(2014), 155-172
Online First (2014) DOI: 10.4028/www.scientific.net/DF.1.155
Permalink: https://www.hzdr.de/publications/Publ-20273