Dense alumina-mullite composite ceramics from alumina and spodumene-albite feldspar binary mixtures: Processing and properties
A processing strategy for obtaining alumina-spodumene ceramics from fine commercial powders is presented. In this work, a spodumene addition to calcined alumina powder was performed and their proportion was explored between 15 and 45 wt%. The industrial spodumene presented secondary phases, mainly a...
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Veröffentlicht in: | Science of sintering 2019, Vol.51 (4), p.445-458 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | A processing strategy for obtaining alumina-spodumene ceramics from fine
commercial powders is presented. In this work, a spodumene addition to
calcined alumina powder was performed and their proportion was explored
between 15 and 45 wt%. The industrial spodumene presented secondary phases,
mainly albite and quartz. Mechanical properties were evaluated. Although
they were lower than those of sintered alumina, based on the achieved values
an adequate behavior in structural applications can be assumed, especially
taking into account that the better mechanical behavior was coupled with the
lower thermal expansion. Relatively low thermal expansion( ? 5 x 10-1?C-1)
behaviors were observed in one of the developed materials. Noncrystalline
phases containing lithium were detected. We assume that all the lithium
oxide incorporated through the spodumene is in the glassy phase after the
sintering of the materials. This difference in lithium concentration in the
composition of the resulting glass affected the thermal expansion of the
developed materials. Particularly with low lithium content (30 wt% of
additive) the material performance was enhanced. This, together with the
mechanical behavior, encourages structural applications with high
thermomechanical solicitations. With the information gathered, a wide range
of materials with specific properties can be obtained by modulating the
spodumene-alumina proportion only.
nema |
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ISSN: | 0350-820X 1820-7413 |
DOI: | 10.2298/SOS1904445H |