Naslov
Crystallization kinetics of mullite formation in diphasic gels containing different alumina components

Autori
Tkalčec, Emilija ; Ivanković, Hrvoje ; Nass, Ruediger ; Schmidt, Helmut

Izvornik
Journal of the European Ceramic Society (0955-2219) 23 (2003); 1465-1475

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Grain size; Kinetics; Mullite; Phase development; Sol-gel process

Sažetak
The crystallization kinetics of mullite formation in diphasic gels containing TEOS-derived amorphous silica and alumina component in different crystalline form and particle size has been studied using quantitative X-ray diffraction (QXRD) with 3:2 mullite as a standard and transmission electron microscopy (TEM). As the source of alumina component, aluminum nitrate nonahydrate, commercial gamma-Al2O3 and boehmite (gamma-AlOOH)were used. The results were consistent with previous studies which indicated that mullite forms initially by nucleation and growth. During the second slow stage of transformation, mullite with approximate 2:1 composition subsequently converts further into 3:2. This process is the fastest in the precursor with the smallest particle size of alumina, and the slowest in the sample with boehmite-derived alumina. In very fine scale of morphology the conversion of 2:1 mullite started even in the first stage of transformation.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemijsko inženjerstvo

POVEZANOST RADA