A Cao-Mgo-Al2O3-SiO2 quaternary system was established with the main crystal phase design based on Diopside, and the effect of once-through sintering heat treatment on microstructure of iron railings glass ceramics wa...A Cao-Mgo-Al2O3-SiO2 quaternary system was established with the main crystal phase design based on Diopside, and the effect of once-through sintering heat treatment on microstructure of iron railings glass ceramics was studied by using DTA, SEM along with measurement of microhardness and volume density. The experimental results show that, when the total amount of FeO and Fe2O3 exceeds 10wt%, a large number of fine nuclei are produced in the annealing process, and the phenomenon of nucleus resorption happens during the process of nucleation heat treatment, which is unfavorable for preparing iron tailings glass ceramics through once-through sintering method. When the annealing temperature from 1250 ℃ to 830 ℃, setting crystallization time for 4h, without heat treatment, crystals are well grown with arrangement and interlocking in glass phase. At 830 ℃ the crystals are well developed, well distributed and of good size; with crystallization time of 4 h the crystals with radial shape have high content and regular arrangement.展开更多
The basic glass of Li2O-Al2O3-SiO2 system using P2O5 as nucleator was prepared by means of conventional melt quenching technology, and the heat-treatment process was determined by using differential thermal analysis. ...The basic glass of Li2O-Al2O3-SiO2 system using P2O5 as nucleator was prepared by means of conventional melt quenching technology, and the heat-treatment process was determined by using differential thermal analysis. The crystalline phases and the microstructure of the glass-ceramics were investigated by using X-ray diffraction and scanning electron microscopy. The results show that the glass based on Li2O-Al2O3-SiO2 oxides using P2O5 as nucleator can be prepared at lower melt temperature of 1 450 ℃ and the glass-ceramics with lower thermal expansion coefficient of 21.6×10-7 ℃-1 can also be obtained at 750 ℃. The glass-ceramics contain a few crystal phases in which the main crystal phase is β-quartz solid solution and the second crystal phase is β-spodumene solid solution. When the heat treatment temperature is not higher than 650 ℃, the transparent glass-ceramics containing β-quartz solid solution can be prepared. β-quartz solid solution changes into β-spodumene solid solution at about 750 ℃. And the appearance of the glass-ceramics changes from translucent, part opaque to complete opaque with increasing （temperature.）展开更多
The influence that the holding time exerts on the microwave dielectric property of the glass-ceramic of SiO2-Al2O3-SrO-ZnO-La2O3under 750℃ is studied.The dielectric property is measured by perturbation method and the...The influence that the holding time exerts on the microwave dielectric property of the glass-ceramic of SiO2-Al2O3-SrO-ZnO-La2O3under 750℃ is studied.The dielectric property is measured by perturbation method and the microcrystalline phase has been analyzed by XRD and SEM.The new glass phase La2ZrTiO7 produced by the reaction(Q=1800,τε=+500ppm/℃) is of great signality to the development of new microwave dielectric materials.The sample which was insulated at 750℃ for 35h with superior dielectric properties: εr=12.82,Q=1150,τε=-19.5ppm/℃.展开更多
Electrolytic manganese residue （EMR） is a waste from electrolytic manganese industry that contains high concentration of toxic substances. Since the EMR disposal in landfill sites has a serious environmental impact,...Electrolytic manganese residue （EMR） is a waste from electrolytic manganese industry that contains high concentration of toxic substances. Since the EMR disposal in landfill sites has a serious environmental impact, new ways of EMR utilization are being sought. Considering the melting of EMR to a glass at high temperature was a relatively less energy-intensive process, EMR was first made into a base glass and then the ground base glass was heat-treated in a certain procedure to make a glass-ceramic and the crystallization process was studied. It was determined by X-ray diffraction （XRD） that the primary crystalline phases of the EMR glass-ceramic were diopside and anorthite, which formed the surface crystallization mechanism with a crystallization activation energy of 429 kJ/mol. Scanning electron microscopy （SEM） observation showed that a layer of small spherical particles with an average size of about 0.5 ~tm were covered on the glass matrix surface, and among them there were some big particles. The low melting temperature and crystallization activation energy make it promising to reuse EMR for glass-ceramic production.展开更多
Three kinds of glass-ceramics, i.e., Mn 2+ doped zinc borosilicate, Eu 2+, Dy 3+ co-doped strontium aluminoborate and Eu 2+, Nd 3+ co-doped calcium aluminoborate were prepared, whose phosphorescence emission band...Three kinds of glass-ceramics, i.e., Mn 2+ doped zinc borosilicate, Eu 2+, Dy 3+ co-doped strontium aluminoborate and Eu 2+, Nd 3+ co-doped calcium aluminoborate were prepared, whose phosphorescence emission band peaks at 525, 516 and 464 nm, respectively. In preparation of these glass-ceramics the base glasses were gained by heating the mixed starting materials at high temperature to get the transparent glasses; then those glasses were heat-treated and turned to opaque glass-ceramics. X-ray diffraction (XRD) shows that the crystallites are ZnSiO 4, SrAl 2O 4 and α-CaAl 2B 2O 7, respectively. It is a useful way to get new LLP materials by the method reported in this work that may be considered as “from glass to crystal”.展开更多
基金Funded by State Administration of Foreign Experts Affairs and the Younger Natural Science Foundation of Liaoning(wzj-2002, 2005229001)
文摘A Cao-Mgo-Al2O3-SiO2 quaternary system was established with the main crystal phase design based on Diopside, and the effect of once-through sintering heat treatment on microstructure of iron railings glass ceramics was studied by using DTA, SEM along with measurement of microhardness and volume density. The experimental results show that, when the total amount of FeO and Fe2O3 exceeds 10wt%, a large number of fine nuclei are produced in the annealing process, and the phenomenon of nucleus resorption happens during the process of nucleation heat treatment, which is unfavorable for preparing iron tailings glass ceramics through once-through sintering method. When the annealing temperature from 1250 ℃ to 830 ℃, setting crystallization time for 4h, without heat treatment, crystals are well grown with arrangement and interlocking in glass phase. At 830 ℃ the crystals are well developed, well distributed and of good size; with crystallization time of 4 h the crystals with radial shape have high content and regular arrangement.
文摘The basic glass of Li2O-Al2O3-SiO2 system using P2O5 as nucleator was prepared by means of conventional melt quenching technology, and the heat-treatment process was determined by using differential thermal analysis. The crystalline phases and the microstructure of the glass-ceramics were investigated by using X-ray diffraction and scanning electron microscopy. The results show that the glass based on Li2O-Al2O3-SiO2 oxides using P2O5 as nucleator can be prepared at lower melt temperature of 1 450 ℃ and the glass-ceramics with lower thermal expansion coefficient of 21.6×10-7 ℃-1 can also be obtained at 750 ℃. The glass-ceramics contain a few crystal phases in which the main crystal phase is β-quartz solid solution and the second crystal phase is β-spodumene solid solution. When the heat treatment temperature is not higher than 650 ℃, the transparent glass-ceramics containing β-quartz solid solution can be prepared. β-quartz solid solution changes into β-spodumene solid solution at about 750 ℃. And the appearance of the glass-ceramics changes from translucent, part opaque to complete opaque with increasing （temperature.）
文摘The influence that the holding time exerts on the microwave dielectric property of the glass-ceramic of SiO2-Al2O3-SrO-ZnO-La2O3under 750℃ is studied.The dielectric property is measured by perturbation method and the microcrystalline phase has been analyzed by XRD and SEM.The new glass phase La2ZrTiO7 produced by the reaction(Q=1800,τε=+500ppm/℃) is of great signality to the development of new microwave dielectric materials.The sample which was insulated at 750℃ for 35h with superior dielectric properties: εr=12.82,Q=1150,τε=-19.5ppm/℃.
基金the National High Technology Research and Development Program (‘863’ Program) of China (No. 2008AA031206)Key Scientific and Technological Projects of Chongqing (No. CSTC2007AB4019)
文摘Electrolytic manganese residue （EMR） is a waste from electrolytic manganese industry that contains high concentration of toxic substances. Since the EMR disposal in landfill sites has a serious environmental impact, new ways of EMR utilization are being sought. Considering the melting of EMR to a glass at high temperature was a relatively less energy-intensive process, EMR was first made into a base glass and then the ground base glass was heat-treated in a certain procedure to make a glass-ceramic and the crystallization process was studied. It was determined by X-ray diffraction （XRD） that the primary crystalline phases of the EMR glass-ceramic were diopside and anorthite, which formed the surface crystallization mechanism with a crystallization activation energy of 429 kJ/mol. Scanning electron microscopy （SEM） observation showed that a layer of small spherical particles with an average size of about 0.5 ~tm were covered on the glass matrix surface, and among them there were some big particles. The low melting temperature and crystallization activation energy make it promising to reuse EMR for glass-ceramic production.
文摘Three kinds of glass-ceramics, i.e., Mn 2+ doped zinc borosilicate, Eu 2+, Dy 3+ co-doped strontium aluminoborate and Eu 2+, Nd 3+ co-doped calcium aluminoborate were prepared, whose phosphorescence emission band peaks at 525, 516 and 464 nm, respectively. In preparation of these glass-ceramics the base glasses were gained by heating the mixed starting materials at high temperature to get the transparent glasses; then those glasses were heat-treated and turned to opaque glass-ceramics. X-ray diffraction (XRD) shows that the crystallites are ZnSiO 4, SrAl 2O 4 and α-CaAl 2B 2O 7, respectively. It is a useful way to get new LLP materials by the method reported in this work that may be considered as “from glass to crystal”.
