Sol-gel synthesis of phosphate ceramic composites II

1998 ◽  
Vol 13 (6) ◽  
pp. 1553-1559 ◽  
Author(s):  
Zhicheng Cao ◽  
Burtrand I. Lee ◽  
William D. Samuels ◽  
Li-Qiong Wang ◽  
Gregory J. Exarhos
Keyword(s):  
Reaction Mechanism ◽  
Solid State ◽  
Solid State Nmr ◽  
Sol Gel ◽  
Ceramic Composites ◽  
Direct Reaction ◽  
Tetraethoxy Silane ◽  
Gel Technique ◽  
Sol Gel Synthesis ◽  
First Time

Phosphate ceramics were synthesized using sol-gel technique of direct reaction of P2O5 with tetraethoxy silane (TEOS) or titanium tetraethoxide (Ti(OEt)4). The reaction mechanism of P2O5 and TEOS was deduced using liquid and solid-state NMR. Hexacoordinated silicon in phosphosilicate gels was observed. A specially structured titanium phosphate-layered Ti(HPO4)2 · 2H2O was synthesized for the first time through the sol-gel method. The gelation process and phase transformations were investigated.

Sol–gel synthesis of alumina modified by phosphorus: a solid state NMR characterization study

1999 ◽  
Vol 9 (10) ◽  
pp. 2637-2646 ◽  
Author(s):  
Juliette Quartararo ◽  
Michel Guelton ◽  
Monique Rigole ◽  
Jean‐Paul Amoureux ◽  
Christian Fernandez ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Sol Gel ◽  
Characterization Study ◽  
Nmr Characterization ◽  
Sol Gel Synthesis

Sol–gel synthesis, phase composition, morphological and structural characterization of Ca10(PO4)6(OH)2: XRD, FTIR, SEM, 3D SEM and solid-state NMR studies

2016 ◽  
Vol 1119 ◽  
pp. 1-11 ◽  
Author(s):  
Simonas Kareiva ◽  
Vytautas Klimavicius ◽  
Aleksandr Momot ◽  
Jonas Kausteklis ◽  
Aleksandra Prichodko ◽  
...  
Keyword(s):  
Phase Composition ◽  
Solid State ◽  
Structural Characterization ◽  
Solid State Nmr ◽  
Sol Gel ◽  
Nmr Studies ◽  
Sol Gel Synthesis

Sol-gel synthesis of phosphate ceramic composites I

1996 ◽  
Vol 11 (1) ◽  
pp. 134-143 ◽  
Author(s):  
Burtrand I. Lee ◽  
William D. Samuels ◽  
Li-Qiong Wang ◽  
Gregory J. Exarhos
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Alkali Metals ◽  
Sol Gel ◽  
Ceramic Composites ◽  
Resonance Spectroscopy ◽  
Sol Gel Synthesis ◽  
Dialkyl Phosphate

Monolithic gels of phosphate ceramics were synthesized using PO(OH)3−x(OR)x and alkoxides of silicon and titanium. The PO(OH)3−x(OR)x species were synthesized from the reaction of P2O5 and ethanol or n-butanol, and the products consisted of approximately equal molar amounts of mono- and dialkyl phosphate. The phosphate gels containing titanium lost less phosphorus than from the gels of silicon/phosphorus upon firing of gels in air. At phosphorus contents above 60 mole %, the gels were completely crystallized upon firing at temperatures above 700 °C, while the gels containing zinc and alkali metals remained amorphous after firing at 850 °C. Solid state nuclear magnetic resonance spectroscopy showed that all of the silicon is hexacoordinated in the phosphate gels containing silicon and titanium upon firing at temperatures above 520 °C

Sol–gel synthesis of 2-dimensional TiO2: self-assembly of Ti–oxoalkoxy–acetate complexes by carboxylate ligand directed condensation

2021 ◽  
Author(s):  
Ruohong Sui ◽  
Connor E. Deering ◽  
Rohen Prinsloo ◽  
Christopher B. Lavery ◽  
Nancy Chou ◽  
...  
Keyword(s):  
Self Assembly ◽  
Sol Gel ◽  
Carboxylate Ligand ◽  
Sol Gel Synthesis ◽  
First Time

2-Dimensional TiO2 is synthesized for the first time by a sol–gel self-assembly of Ti–oxoalkoxy–acetate complexes.

Characterization of SrBi2Nb2O9 Thin Films Prepared by Sol Gel Technique

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Gel Technique ◽  
High Degree ◽  
First Time

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thicknesses of 0.1, 0.2, and 0.4 μ were grown by Sol-gel technique on silicon, and annealed at 650°C. The SBN films were investigated by Raman scatering for the first time. Raman spectra in some of the samples present bands around 60, 167, 196, 222, 302, 451, 560, 771, 837, and 863 cm−1, which correspond to the SBN formation. The study indicates that the films are inhomogeneous, and only in samples with thicknesses 0.4 μ the SBN material was found in some places. The prominent Raman band around 870 cm−1, which is the A1g mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift in different places in the same sample, as well as from sample to sample. The frequency shifts and the width of the Raman bands are discussed in term of ions in non-equilibrium positions. FT-IR spectra reveal a sharp peak at 1260 cm−1, and two broad bands around 995 and 772 cm−1. The bandwidths of the latter two bands are believed to be associated with the presence of a high degree of defects in the films. The experimental results of the SBN films are compared with those obtained in SBT (T=Ta) films. X-ray diffraction and SEM techniques are also used for the structural characterization.

Multi-Phasic Ceramic Composites made by Sol-Gel Technique

1984 ◽  
Vol 32 ◽  
Author(s):  
Rustum Roy ◽  
S. Komarneni ◽  
D.M. Roy
Keyword(s):  
Single Phase ◽  
Crystal Size ◽  
Sol Gel ◽  
Ceramic Composites ◽  
Silver Halides ◽  
Metal Atoms ◽  
Metallic Salts ◽  
Second Phases ◽  
Gel Technique ◽  
Work Done

ABSTRACTInstead of aiming to prepare homogeneous gels and xerogels, this paper reports on work done to prepare deliberately diphasic materials. This has been achieved by three different paths: (1) mixing 2 sols; (2) mixing 1 sol with 1 solution; and (3) post formation diffusion of either one or two solutions.By the last named process we have made SiO2, mullite and alumina based composites, with silver halides, BaSO4, CdS, etc., as the dispersed phase. The crystal size can be confined to the initial pores by rapid diffusion giving rise to extremely fine second phases in the submicron range. Subsequent reduction of appropriate metallic salts can be used to give finely dispersed metals (e.g. Cu, Ni) in essentially any xerogel matrix. The open porosity makes these metal atoms very accessible.By the first two processes we have made both single phase and di-phasic gels of the same composition (prototype: mullite) and shown that though they cannot be distinguished by XRD, SEM, and TEM, by DTA and thermal processing, they are radically different. Such di-phasic gels store more metastable energy than any other solids.

Sign in / Sign up

Export Citation Format

Share Document