Please use this identifier to cite or link to this item: doi:10.22028/D291-24536
Title: Microstructure and high temperature 4-point bending creep of sol-gel derived mullite ceramics
Author(s): Ivankovic, Hrvoje
Tkalcec, Emilija
Rein, Rüdiger
Schmidt, Helmut K.
Language: English
Year of Publication: 2006
OPUS Source: Journal of the European Ceramic Society. - 26. 2006, 9, S. 1637-1646
SWD key words: Mikrostruktur
DDC notations: 620 Engineering and machine engineering
Publikation type: Journal Article
Abstract: Four-point bending creep behavior of mullite ceramics with monomodal and bimodal distribution of grain sizes was studied in the temperature range of 1320-1400 °C under the stresses between 40 and 160 MPa. Mullite ceramic with bimodal grain size distribution was prepared using aluminum nitrate nonahydrate as alumina precursor. When ã-Al2 O3 or boehmite were used as alumina precursors, mullite grains are equiaxial with mean particle size of 0.6 ìm for the former and 1.3 ìm for the latter alumina precursor. The highest creep rate exhibited the sample with monomodal morphology and grains in size of 0.6 ìm, which is about one order of magnitude greater than that for the monomodal morphology but with grains in size of 1.3 ìm. The highest activation energy for creep (Q = 742 ± 33 kJ/mol) exhibits mullite with equiaxial grains of 1.3 ìm, whereas for sample with smaller equiaxial grains the activation energy is much smaller and similar to mullite ceramics with bimodal grain morphology. Intergranular fracture is predominant near the tension surface, while transgranular more planar fracture is predominant near the compression surface zone.
Link to this record: urn:nbn:de:bsz:291-scidok-31108
Date of registration: 3-May-2010
Faculty: SE - Sonstige Einrichtungen
Department: SE - INM Leibniz-Institut für Neue Materialien
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