Publications Scientifiques

Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/10

Browse

Author: search.filters.author.Aboutaleb, DjamilaSubject: search.filters.subject.Phase separation

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Ostwald ripening phenomena in B 2O 3-PbO glass system
    (2010) Aboutaleb, Djamila; Iratni, A.; Safi, Brahim
  • No Thumbnail Available
    Item
    Phase separation and chemical durability in the SiO2-B2O3-Na2O (SBN) glass system
    (2012) Aboutaleb, Djamila; Safi, Brahim; Jbara, O.; Iratni, A.; Douglad, J.
    Sodium borosilicates glasses were treated isothermically several times. In present work, the effect of phase separation on chemical durability and the electric resistivity was investigated. In addition, the effect of chemical composition and addition of calcium on the kinetics and rate of leaching of these glass materials in hydrochloric acid (3M HCl) was also investigated. The system studied exhibited phase separation starting from 550 ºC. Present results showed that the chemical durability was weakened upon phase separation. On the other hand, chemical durability increased with increasing SiO2 content and reducing the alkaline oxides (Na2O) content. Results also showed a drastic decrease in the ionic electric conductivity (increase in resistivity) with decreasing C = (Na2O + B2O3)/SiO2 (reduction of Na2O). The effect of chemical composition on the rate of leaching showed that boron and sodium are dissolved much more quickly than silicon. The greater the content of Na2O and B2O3 in glass, the more soluble the glass becomes. However, addition of silica results a decrease in glass solubility. These results indicate that substitution of sodium by calcium induces an acceleration of the kinetics of deterioration
  • No Thumbnail Available
    Item
    Effect of isothermal heat treatment time on structural transformation and crystallization of B2O3-PbO glass
    (2008) Aboutaleb, Djamila; Iratni, A.; Safi, Brahim
    Lead borate glass was prepared by the quench method, followed by treatment at its isothermal temperature at different time periods. When the sample was rapidly cooled from the melt, it showed two distinguished opalescent layers. The SEM analysis and XRD pattern provide characteristics of glass without XRD peaks and their morphology show the aggregated spherical particles in the phase separated glass. This data show that phase separation occurred even when the melts were rapidly cooled, however, the sample shows a Ostwald ripen with increasing time of heat treatment, which implies that the size of particles increases and their number decreases. When changing the sample's composition by adding lead oxide (PbO), the sample crystallizes directly upon heat treatment. The infrared absorption spectra show shift edge for sample glass with heat treatment, which indicates a change of structural configuration, i.e. conversion of tetrahedral boron on triangular boron coordination