Vitrification, crystallization behavior and structure of zinc aluminosilicate glasses

The glass formation, crystallization behavior and structure were investigated in the ZnO-Al2O3-SiO2 system. The boundaries of the glass forming region are defined, indicating the absence of glasses along the ZnO-SiO2 binary and the role of Al to improve glass formation. The crystallization behavior has been clarified for representative glass compositions showing first crystallization of willemite near the ZnO-SiO2 binary and a metastable zinc aluminosilicate solid solution for higher Al2O3/SiO2 content. Gahnite appears as a second phase and is mainly present near the center of the tectosilicate join. Glass structure was studied using Al-27 NMR spectroscopy, neutron and X-ray diffraction and molecular dynamics simulation. Both Al and Zn are shown to be distributed between four-fold and five-fold sites. The proportion of Al-[(4]) is more important near the ZnAl2O4-SiO2 join. A remarkable similar behavior is revealed for the glass forming ability and structural properties between MgO and ZnO aluminosilicate systems.

Automated summary

The study investigates the glass formation, crystallization behavior, and structure in the ZnO-Al2O3-SiO2 system, showing the significant role of Al in enhancing glass formation.