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Microstructural Analysis of Sintered High‐Conductivity Zirconia with Al 2 0 3 Additions
Author(s) -
BUTLER E.P.,
DRENNAN J.
Publication year - 1982
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1982.tb10336.x
Subject(s) - grain boundary , materials science , cubic zirconia , transmission electron microscopy , sintering , ceramic , scanning electron microscope , ionic conductivity , amorphous solid , phase (matter) , conductivity , scanning transmission electron microscopy , diffusion , mineralogy , analytical chemistry (journal) , grain boundary diffusion coefficient , microstructure , crystallography , metallurgy , composite material , nanotechnology , chemistry , electrolyte , thermodynamics , physics , electrode , chromatography , organic chemistry
Transmission electron microscopy (at 100 and 1000 kV potential) and analytical scanning transmission electron microscopy were used to study α‐Al 2 0 3 second‐phase particles and their interactions with grain boundaries in two high‐conductivity Y 2 0 3 /Yb 2 0 3 stabilized zirconia ceramics containing deliberate additions of the alumina as a sintering aid. Most of the Al 2 0 3 particles were intragranular and microanalysis showed that they contained inclusions rich in Zr or Si plus Zr. Al 2 O 3 particles at grain boundaries were frequently associated with amorphous cusp areas rich in Si and Al. The results suggest that the Al 2 0 3 acts as a scavenger for SiO 2 , removing it from grain‐boundary localities. A model is proposed whereby this process occurs as the boundaries meet the second‐phase particles, assisted by rapid grain‐boundary diffusion. Such an ZrO 2 ‐Al 2 O 3 ‐SiO 2 interaction and partitioning is predicted thermodynamically and offers a possible explanation for the improvements in ionic conductivity brought about by Al 2 O 3 additions, as reported in the literature.