کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1478461 991219 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Low-temperature Ti-containing 3:2 and 2:1 mullite nanocrystals from single-phase gels
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Low-temperature Ti-containing 3:2 and 2:1 mullite nanocrystals from single-phase gels
چکیده انگلیسی

TiO2-containig single-phase gels with (Al2O3 + TiO2)/(SiO2) 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. 27Al 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 TiO2 incorporated into the mullite structure increased on raising the amount of nominal TiO2 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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the European Ceramic Society - Volume 27, Issue 7, 2007, Pages 2655–2663
نویسندگان
, , ,