The Preparation And Properties Of Y-Al-Si-O-N Oxynitride Glasses And Glass-ceramics

Oxynitride glasses formed at grain boundaries in Si3N4and SiAlON ceramics are essentially alumino-silicate glasses in which nitrogen atoms substitute for oxygen atoms in the glass network. This substitution contributed to the formation of more cross-linked glass network and structure, which lead to the change of some mechanical properties (such as higher elastic moduli, hardness, strength and fracture toughness), thermal properties (higher glass transition temperature and lower thermal expansion coefficient) and chemical properties (lower leaching rate). Due to the advantage properties, oxynitride glasses are likely to be used in some potential areas, such as glass fibers, Si3N4ceramic seals and transparent armor.In the present work, some Y-Al-Si-O-N oxynitride glasses and glass-ceramics were studied. The obtained samples were characterized by differential scanning calorimeter (DSC), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV/visible spectroscopy, which were used to study the glass structure, thermal properties, mechanical properties, ballistic resistance and the relationship between them.The structure, properties and crystallization behavior of two series (N-9and N-18series) of zirconia-doped Y-Al-Si-O-N oxynitride glasses and glass-ceramics were studied. It was found that the addition of zirconia is effective in preparing Y-Al-Si-O-N oxynitride glasses with lower glass transition temperature and higher hardness, while increased the density. With the increasing N content, the density, hardness, glass transition temperature increase and the thermal expansion coefficient decrease. From the analysis of XRD and SEM, the Zr and N content have an effect on the types and size of the crystalline phases.The mechanical properties, optical transmittance, ballistic resistance mirostructure and crystalline behavior of some oxynitride glass and glass-ceramics with different modifier elements were studied. UV/visible wavelength region light transmission spectra of samples showed that the transmittance of the obtained glasses (1mm,2mm and3mm thickness) can reach up to80%in the visible region (above400nm). It was found that the Drel value of oxynitride glasses can reach up to2.56and is higher than that of sapphire, which is2.42. The results of XRD and SEM indicate that the difference of modifier elements has a effect on the crystalline behavior of oxynitride glasses, and the oxynitride glasses containing Y were more difficult to precipitate crystalline phase than oxynitride glasses containing Ca and Mg.