Electric Field-Assisted Sintering in Comparison with the Hot Pressing of Yttria-Stabilized Zirconia
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Autor:
Langer, J; Hoffmann, MJ; Guillon, O
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Quelle:
JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 2011, Band 94, Heft 1, S. 141-138
Abstract
This study aims at comparing hot pressing (HP) and the electric
field-assisted sintering technique (FAST) of 8 mol% yttria-stabilized
zirconia (8YSZ). Three different ionic conductive nano- and submicron
powders were investigated, with a median particle size of 20-30, 51-65,
and 150 nm, respectively. Processing parameters were kept identical for
both sintering methods: sample geometry, heating schedule, applied
pressure, and atmosphere. Investigations of densification and
microstructural characterization reveal that under the same conditions
FAST and HP sintered samples behave similarly. The analysis of the
sintering curves shows that the densification mechanism is the same for
both sintering methods (grain-boundary diffusion). An increase of the
heating rate up to 150 K/min does not modify the densification
mechanism. The sintering trajectory reveals that grain size depends only
on density and not on the sintering method and grains have no
preferential orientation. Secondary ion mass spectroscopy shows that
both types of specimens are contaminated with carbon only superficially.
Measurements of the electrical conductivity at high temperature show no
significant difference between HP and FAST samples.