Title :

Crystallization of amorphous silicates far from equilibrium part I: A versatile nitrate-based sol-gel synthesis of amorphous porous Ca,Mg-rich silicates

Author(s) :

Gillot, Jessy [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Roskosz, Mathieu [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Leroux, Hugues [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Depecker, Christophe [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]

Journal title :

Journal of Non-Crystalline Solids

Volume number :

357

Pages :

3461-3466

Publication date :

2011

HAL domain(s) :

Planète et Univers [physics]/Astrophysique [astro-ph]
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre
Chimie/Matériaux
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]

English abstract : [en]

An easy-to-use, comprehensive sol–gel method is developed to produce amorphous calcium and magnesium silicates from nitrate precursors and TetraEthOxySilane (TEOS). Final products were designed to suit basic prerequisites ...
Show more >An easy-to-use, comprehensive sol–gel method is developed to produce amorphous calcium and magnesium silicates from nitrate precursors and TetraEthOxySilane (TEOS). Final products were designed to suit basic prerequisites of starting materials for experimental investigation of crystallization around the glass transition temperature range. After gelification, thermo-gravimetric methods and infrared-spectroscopy were used to follow dehydration, decarbonation and denitrification of the xerogel. A temperature of 500 °C is found to successfully remove volatiles without causing crystallization. The microstructure revealed by transmission electron microscopy (TEM) consists of 10–20 nm individual mesoparticles of 10–20 nm. Samples annealed at 500 °C were found entirely amorphous at the TEM scale. The porosity observed by TEM and characterized by nitrogen adsorption–desorption is homogeneous and varies from 4.6 to 8.5 nm as a function of the composition. Bulk analyses by ICPMS and local analyses by EDS-TEM demonstrate that the stoichiometry can be achieved and the homogeneity is confirmed at least down to 100 × 100 nm. At lower scale, irradiation by the electron beam produces a significant volatilization of Ca and Mg, which makes chemical analyses unreliable. Pros and cons of the method and special cares for specific applications are discussed. The method was also successfully used to produce a wider range of amorphous analogs having complex compositions or containing trace elements for applications in the field of mineral physics and chemistry.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
ENSCL
CNRS
INRA

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires

Submission date :

2019-05-16T15:15:09Z
2021-02-16T08:49:11Z