Crystallization of Glasses Containing K2O, PbO, BaO, Al2O3, B2O3, and TiO2

The objective of this work was to obtain glass-ceramics from stable glasses, with a composition of barium, lead, and potassium titanate phases, for use as semiconductors. For this purpose, the glass-ceramic technique was used to control crystal growth and obtain a fine-grained microstructure. Various glasses containing K2O, PbO, BaO, Al2O3, B2O3, and TiO2 were prepared using a melt-quenching method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed a single amorphous phase of all samples. Infrared spectra confirmed the presence of B-O bonds stretching vibrations of (B3O6)(3-) boroxol rings and BO3 triangles, as well as Ti-O stretching vibrations of (TiO6/2) and (AlO6/2) octahedral units. Thermal analyses confirmed the presence of one or more crystallization peaks in the range of 700 to 744 degrees C. On this base, they were heat-treated to promote crystal growth. XRD and SEM detected Ba4Ti12O27, Ti7O13, and BaTiO3 phases, homogeneously distributed throughout the material with fine crystallite size. In addition, crystallized glasses' (glass-ceramics) properties were determined; the density values were 2.8-3.55 g/cm(3); the chemical resistance to acidic and basic media was low; and the band-gap values were in the range of 2.88 to 3.05 eV. These results suggest that crystallized glasses may have application in photocatalysis.

Automated summary

The objective of this study was to obtain glass-ceramics with a composition of barium, lead, and potassium titanate phases for use as semiconductors. The glass-ceramic technique was used to control crystal growth and obtain a fine-grained microstructure. The results suggest that crystallized glasses may have application in photocatalysis.