6533b7cefe1ef96bd1257933

RESEARCH PRODUCT

Low-temperature Ti-containing 3:2 and 2:1 mullite nanocrystals from single-phase gels

Javier AlarcónFrancisco EstevanEsther Ruiz De Sola

subject

Materials scienceMineralogychemistry.chemical_elementMulliteAluminium nitratelaw.inventionchemistry.chemical_compoundchemistryChemical engineeringlawAluminiumDifferential thermal analysisMaterials ChemistryCeramics and CompositesMagic angle spinningCrystallizationTitanium isopropoxidePowder diffraction

description

Abstract TiO 2 -containig single-phase gels with (Al 2 O 3  + TiO 2 )/(SiO 2 ) molar ratios 3/2 and 2/1 were prepared by gelling mixtures of aluminium nitrate, tetraethylorthosilicate and titanium isopropoxide. Gels were fast heated at several temperatures up to 1100 °C. Dried and heated gels were characterized by differential thermal analysis (DTA), magic angle spinning nuclear magnetic resonance (MAS-NMR), X-ray powder diffraction (XRD), and scanning and transmission electron microscopies (SEM and TEM). Coupled DTA and XRD results of gels fast heated at 900 °C showed the crystallisation of two mullites as well as a small amount of alumina-silica spinel. 27 Al NMR spectra showed the formation of pentacoordinated aluminium before mullite crystallization. The increase of lattice parameters of single-phase mullites heated at 1100 °C indicated that the amount of TiO 2 incorporated into the mullite structure increased on raising the amount of nominal TiO 2 in both series. SEM and TEM images of heated gels at 1100 °C displayed the formation of well-shaped parallelepiped of titanium-doped mullite nanocrystals with crystalline anisotropy.

yearjournalcountryeditionlanguage
2007-01-01Journal of the European Ceramic Society
https://doi.org/10.1016/j.jeurceramsoc.2006.09.014