Search results for "Solubilité"
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Supercritical hydrothermal synthesis of ZnO nanopowders beyond the critical point : understanding of nucleation and growth steps
2014
The supercritical hydrothermal synthesis of nanopowders (especially metal oxide) has been widely studied. To the best of our knowledge, no nanoparticle formation mechanism has been published yet. In this prospect, this study is dedicated to the understanding of metal oxide nanoparticle nucleation and growth mechanisms. For this purpose, zinc oxide is used as a model material. First, the influence of synthesis operating conditions such as pressure, temperature, pH, precursor concentrations and solution flow rates on particle morphological properties (size, particle size distribution or morphologies) has been investigated. Hence, two approaches have simultaneously been carried out. The first …
Etude expérimentale et modélisation thermodynamique du système CaO-SiO2-(Al2O3)-H2O
2012
The aim of this work is to build a thermodynamic model at 25°C to describe the main hydrates of ordinary Portland cement with or without supplementary cementitious materials (SCM) : calcium hydrosilicates. With high aluminium content, SCM in blended cements modify the nature and the composition of the hydrates of cement paste.The simplified model system CaO-SiO2-H2O was studied by synthesising of C-S-H with identical protocol and analysis. We distinguished, hydration solutions undersaturated and supersaturated from Portlandite.This last system has been extended to CaO-Al2O3-SiO2-H2O system. Then, we determined the most suitable protocol to synthesize pure C-A-S-H.The nanoparticular nature a…