Papers by Keyword: Oriented Crystallization

Abstract: The polar glass-ceramics of 2.0SrO-1.0TiO2-2.9SiO2 system were prepared by the process of recrystallization with additional applied isothermal and electric field. The results showed that the glass-ceramics piezoelectric constant d33 was 12×10-12 C/N. The study of its oriented crystallization by SEM and XRD indicated that Sr2TiSi2O8 crystal performed oriented growth, which was perpendicular to the glass surface and made it be orientally crystallized with the assisted the isothermal and electric field. The further experimental results showed that the additional electric field reduced the crystallization activation energy, which provided a force for the isothermal orientating crystallization process.

Abstract: The electrochemically induced nucleation and crystallization in a glass with the basic composition (mol%) 52.6 SiO2 · 18.7 Al2O3 · 14.3 MgO · 7.8 TiO2 · 4.7 B2O3 · 2.0 CaO leads to the formation of oriented mullite crystals. Electron microscopy techniques (energydispersive X-ray microanalysis and electron backscatter diffraction) were used to analyze the composition and the orientation of the crystals in the glassy matrix. The mean composition of the mullite crystals matches the formula Al4,65Ti0,11Si1,24O9,675. The electron backscatter diffraction pattern is consistent with data from the literature that needle-like mullite crystals are fast-growing parallel to the crystallographic c-axis [001]. The composition of the melt grown mullite crystals does not depend on the melting temperature in the range between 1230 °C and 1350 °C.