Estudo das estruturas cristalinas e micrografias de vitrocerâmicas produzidas a partir de vidro com adição de Nb2O5

Abstract

Glass-ceramic materials, from the glass powder of windshield, were produced and characterized. Two compositions were studied, the composition of the windshield glass powder itself, Si2O-Na2O-CaO-MgO-Al2O3, and another with 10% niobium pentoxide, Nb2O5, in this system. The powders were characterized by X-ray fluorescence spectrometry and laser scattering particle size distribution to determine the powder particle size of the samples. The parts were sintered at 650 ° C, 700 ° C, 750 ° C and 800 ° C. Each batch of parts was evaluated linear retraction, apparent porosity and scanning electron microscopy, SEM. We also performed X-ray diffraction, X-ray excited photoelectron spectroscopy, XPS; spectroscopy in the infrared region and Raman scattering vibration spectroscopy. The difference in crystalline structures and glass ceramic micrographs were observed with and without addition of 10% Nb2O5. The densification of the pieces remains constant until the temperature of 750 ºC, beginning to decrease after 800 ºC. The addition of niobium oxide favored the formation of the crystalline structures of Isolueshita and Zeolite at 700 ºC. It also showed a higher amount of crystals, with higher sodium content and lower calcium content. This indicates a higher incorporation of the hydroxides of the primary elements (Nb / Si) and (Na / Si), during the heat treatment, allowing the development of crystalline structures inside the glass matrix and consequently typical spectra of more crystalline structures. The Nb2O5 also favored the control of the dimensions in the samples, resulting in a lower variation of values in the linear retraction of the glass-ceramic materials.