Lithium aluminosilicate （LAS） glasses are generally difficult to prepare because of their high melting temperature. In this study, the preparation of LAS glasses was achieved at a relatively low melting temperature....Lithium aluminosilicate （LAS） glasses are generally difficult to prepare because of their high melting temperature. In this study, the preparation of LAS glasses was achieved at a relatively low melting temperature. The batch containing MgO-ZnO-LiEO- Al2O3-SiO2 was melted in a platinum crucible at 1550℃ for 2 h and was then followed by two- or three-step heat treatment processes for nucleation and crystal growth. The characterizations were carried out by differential thermal analysis, X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and UV-Vis-NIR scanning spectrophotometry. The hexagonal stuffed β-eucryptite solid solution crystallized at 840-960℃. Most of the hexagonal β-eucryptite solid solution transformed into the tetragonal β-spodumene solid solution at 1100℃. Almost all the aluminum atoms entered into the tetrahedral sites in the aluminosilicate network of the 6- eucryptite/β-quartz solid solution. All of the Al atoms did not belong to the aluminosilicate network of the β-spodumene solid solution. The glass ceramic with a mean grain size of 10-20 nm is transparent, the transmittance reaches -85% in the visible light wavelength.展开更多
The microstructure of CaO-P_2O_5-SiO_2-MgO-F^- glass-ceramics duringcrystallization were investigated and the crystallized phases were identified with DTA (DifferentialThermal Analysis), SEM (Scanning Electron Microsc...The microstructure of CaO-P_2O_5-SiO_2-MgO-F^- glass-ceramics duringcrystallization were investigated and the crystallized phases were identified with DTA (DifferentialThermal Analysis), SEM (Scanning Electron Microscope) and XRD (X- ray Diffraction) techniques. Themechanical properties such as bending strength and fracture toughness, as well as their changes withadvancing crystallization were determined. The results show that the changes of the mechanicalproperties are correlated with the microstructures. The sample heated up to 810 deg C and soaked for4 h has smaller crystalline size and less volum fraction of fluorophlogopite, so it has higherbending strength (about 190 MPa), and higher crack toughness (about 2.63 MPa centre dot m^1/2).展开更多
The effects of Co2O3 on the crystallization and colorization of lithium aluminosilicate glass ceramic were investigated by using differential thermal analysis (DTA), X-ray diffractometry (XRD) and scanning electron mi...The effects of Co2O3 on the crystallization and colorization of lithium aluminosilicate glass ceramic were investigated by using differential thermal analysis (DTA), X-ray diffractometry (XRD) and scanning electron microscope (SEM). The results showed that the introduction of Co2O3 not only changed the color of lithium aluminosilicate glass but also affected its crystallization by increasing the crystallizing maximum peak temperature (Tp) and weakening the crystallization ability. In addition, the color of LAS glass ceramics could be achieved by controlling the suitable Co2O3 and appropriate crystallization temperature.展开更多
基金This work was financially supported by the Ministry of Education of China (No.KB20026)
文摘Lithium aluminosilicate （LAS） glasses are generally difficult to prepare because of their high melting temperature. In this study, the preparation of LAS glasses was achieved at a relatively low melting temperature. The batch containing MgO-ZnO-LiEO- Al2O3-SiO2 was melted in a platinum crucible at 1550℃ for 2 h and was then followed by two- or three-step heat treatment processes for nucleation and crystal growth. The characterizations were carried out by differential thermal analysis, X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and UV-Vis-NIR scanning spectrophotometry. The hexagonal stuffed β-eucryptite solid solution crystallized at 840-960℃. Most of the hexagonal β-eucryptite solid solution transformed into the tetragonal β-spodumene solid solution at 1100℃. Almost all the aluminum atoms entered into the tetrahedral sites in the aluminosilicate network of the 6- eucryptite/β-quartz solid solution. All of the Al atoms did not belong to the aluminosilicate network of the β-spodumene solid solution. The glass ceramic with a mean grain size of 10-20 nm is transparent, the transmittance reaches -85% in the visible light wavelength.
文摘The microstructure of CaO-P_2O_5-SiO_2-MgO-F^- glass-ceramics duringcrystallization were investigated and the crystallized phases were identified with DTA (DifferentialThermal Analysis), SEM (Scanning Electron Microscope) and XRD (X- ray Diffraction) techniques. Themechanical properties such as bending strength and fracture toughness, as well as their changes withadvancing crystallization were determined. The results show that the changes of the mechanicalproperties are correlated with the microstructures. The sample heated up to 810 deg C and soaked for4 h has smaller crystalline size and less volum fraction of fluorophlogopite, so it has higherbending strength (about 190 MPa), and higher crack toughness (about 2.63 MPa centre dot m^1/2).
文摘The effects of Co2O3 on the crystallization and colorization of lithium aluminosilicate glass ceramic were investigated by using differential thermal analysis (DTA), X-ray diffractometry (XRD) and scanning electron microscope (SEM). The results showed that the introduction of Co2O3 not only changed the color of lithium aluminosilicate glass but also affected its crystallization by increasing the crystallizing maximum peak temperature (Tp) and weakening the crystallization ability. In addition, the color of LAS glass ceramics could be achieved by controlling the suitable Co2O3 and appropriate crystallization temperature.
