Premium
Zirconia‐Alumina Nanoparticles Prepared by Laser Evaporation: Powder Characterisation by TEM and 27 Al MAS NMR
Author(s) -
Müller Eberhard,
Oestreich Christiane,
Klemm Volker,
Brendler Erica,
Ferkel Hans,
Riehemann Werner
Publication year - 2002
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/1521-4117(200207)19:3<169::aid-ppsc169>3.0.co;2-0
Subject(s) - crystallite , materials science , microstructure , cubic zirconia , amorphous solid , magic angle spinning , transmission electron microscopy , nanoparticle , evaporation , chemical engineering , ceramic , ion , analytical chemistry (journal) , mineralogy , crystallography , composite material , nanotechnology , nuclear magnetic resonance spectroscopy , chemistry , metallurgy , organic chemistry , physics , engineering , thermodynamics
Contrary to predictions of the ZrO 2 ‐Al 2 O 3 phase diagram powders of solid solutions of alumina in zirconia with up to 40 mol% Al 2 O 3 are described in the recent literature. Up to now the interpretations of the microstructure of these materials are still inconsistent. Therefore we reinvestigated nanopowders prepared by laser evaporation starting from a mixture of 55 mol% ZrO 2 and 45 mol% Al 2 O 3 by analytical high resolution transmission electron microscopy (TEM) and 27 Al magic angle spinning nuclear magnetic resonance (MAS NMR). The results reveal that in case of this preparation route a heterogeneous powder system is formed consisting dominantly of nanocrystallites of zirconia with an incorporation of, obviously, only a very small amount of alumina, and that the crystallites are surrounded by an amorphous layer of predominantly alumina. No indication was found that Al 3+ ions occupy seven‐ or eight‐fold co‐ordinated sites of Zr 4+ ions. A simple kinetic model for the formation of the nanoparticles' microstructure is given.