Improvement of sintering and microstructural homogeneity of a diphasic mullite

Kara, Ferhat; Şener, Olcay

doi:10.1016/s0955-2219(00)00280-6

Cited by 13 publications

(6 citation statements)

References 16 publications

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“…When sintering temperature is above 1250 • C, the viscosity of amorphous phase decreases sharply with the increase of sintering temperature. 18,19 So the main sintering mechanism was still the viscous flow of the amorphous phase. Only in the stage of holding at final temperature, when all of amorphous phase almost transform into mullite, solid-state diffusion play a main role in the densification process.…”

Section: Methods Of Characterizationmentioning

confidence: 99%

Transparent mullite ceramic from single-phase gel by Spark Plasma Sintering

Zhang

Wang

et al. 2009

Journal of the European Ceramic Society

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Section: Methods Of Characterizationmentioning

confidence: 99%

Transparent mullite ceramic from single-phase gel by Spark Plasma Sintering

Zhang

Wang

et al. 2009

Journal of the European Ceramic Society

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“…17 The finer the alumina particle, the smaller the mullite grain size. The presence of equiaxial grains has generally been associated with the absence of glassy phase and with high alumina compositions, 8,16,18,19 whereas stiff skeleton of interlinked elongated mullite crystals are associated with presence of liquid phase, and stoichiometric or low-alumina compositions. 16 The gels C and D exhibited stoichiometric 3:2 mullite composition, but the densification of powders was almost complete prior to mullite crystallization as shown in Fig.…”

Section: Microstructure Of Sintered Compactsmentioning

confidence: 99%

Correlation of the precursor type with densification behavior and microstructure of sintered mullite ceramics

Ivanković

Tkalčeć

Naß

et al. 2003

Journal of the European Ceramic Society

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The effect of alumina component in diphasic mullite precursors containing alkoxy derived silica on the crystallization and sin tering behavior of compacts was studied. The phenomena observed were characterized using differential thermal analysis (DTA), powder X ray diffraction (XRD), dilatometry and transmission and scanning electron microscopy (TEM, SEM). In order to change the characteristics of as prepared gels, the alumina source was varied while keeping the silica source constant. Al(NO 3) 3. 9H 2 O, g Al 2 O 3 and boehmite (g AlOOH) were used as the alumina source and TEOS as the silica source. Clear differences were found in the microstructure of sintered samples derived from the precursors with aluminum nitrate nonahydrate in comparison to the sam ples containing g Al 2 O 3 or boehmite (g AlOOH). The former exhibited elongated mullite grains embedded into the ''equiaxial mullite matrix''. This morphology is due to the overlapping of mullite crystallization and viscous flow sintering temperatures. Transient alumina, either added as g Al 2 O 3 or formed in situ by decomposition of boehmite, shifts the mullite formation above the sintering temperature, and enables formation of equiaxial mullite. The smaller are the transient alumina particles, the smaller are mullite grains of sintered bodies.

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“…[20][21][22] The formation of the ␣-alumina phase during the mullite synthesis is considered to be an indicator of precursor heterogeneity. 23 When the samples were annealed at 1000 • C, the XRD profile of sample G0 did not show a change in crystal composition, i.e. both the spinel and ␣-alumina phase were still observed.…”

Section: Sample Characterizationmentioning

confidence: 93%