Positron Annihilation Study of Zirconia Nanopowders and Nanoceramics Stabilized by Magnesia and Ceria

Positron Annihilation Study of Zirconia Nanopowders and Nanoceramics Stabilized by Magnesia and Ceria

Positron lifetime (LT) and coincidence Doppler broadening (CDB) measurements on nanopowders and ceramics of ceria‐ and magnesia‐stabilized zirconia (CeSZ and MgSZ, respectively) are presented. The nanopowders were prepared by the coprecipitation technique. Effects of nanopowder calcination and sinte...

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Bibliographic Details
Published in:Journal of the American Ceramic Society Vol. 97; no. 3; pp. 982 - 989
Main Authors: Prochazka, Ivan, Cizek, Jakub, Melikhova, Oksana, Konstantinova, Tetyana E., Danilenko, Igor A., Yashchishyn, Igor A.
Format: Journal Article
Language:English
Published: Columbus Blackwell Publishing Ltd 01-03-2014
Wiley Subscription Services, Inc
Subjects:
Ceramic sintering
Grain boundaries
Ions
Nanostructured ceramics
Temperature effects
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Summary:Positron lifetime (LT) and coincidence Doppler broadening (CDB) measurements on nanopowders and ceramics of ceria‐ and magnesia‐stabilized zirconia (CeSZ and MgSZ, respectively) are presented. The nanopowders were prepared by the coprecipitation technique. Effects of nanopowder calcination and sintering at various temperatures were investigated. In the nanopowders, the two kinds of open‐volume defects associated with grain boundaries (GBs) could be identified via positron trapping: (i) vacancy‐like misfit defects situated along GBs and (ii) larger defects at the intersections of at least three GBs (triple points). CDB measurements on CeSZ compacted nanopowders indicated a segregation of Ce ions along GBs. A few percent fractions of positrons were found to form positronium localized in pores of ≈1.8 nm diameter in compacted nanopowders. Sintering of nanopowders at 1500°C appeared to be sufficient for disappearance of pores and triple point defects. In sintered ceramics, contrary to compacted nanopowders, positrons were trapped in zirconium vacancies in grain interiors.
Bibliography:The Czech Science Foundation - No. P108/11/1396
The Ministry of Education
ArticleID:JACE12716
Sports of the Czech Republic - No. LH12173
istex:462D546D2A6584DDA8BB2CBD21D6E94F569A588B
ark:/67375/WNG-HPNT7PF8-Z
NAS - No. 89/12-H
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.12716