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1.
Water quenching-induced cracked-glass was used as parent glass to prepare glass-ceramics in this work. The cracked-glass panel was first heat-treated through two-step method, i.e. sintering for 1 h at 860 °C and subsequent crystallization for 1.5 h at 1080 °C, and then naturally cooled down to room temperature to be transformed into glass-ceramics. XRD and SEM observations confirm that the cracked-glass can be used as parent glass to deposit β-wollastonite crystals depending on crack crystallization mechanism. The volume densities, porosities and bending strengths of the glass-ceramics are respectively around 2.7 g/cm3, 0.5% and 40 MPa. As compared with glass-ceramics prepared by conventional glass grain sintering process, the new type of glass-ceramics produced by CGC process shows pseudo-bioclastic texture and has less gas pore flaws, and may therefore become an alternative for materials of architectural decoration. 相似文献
2.
以滑石、高岭土和化学试剂合成了两种析晶促进剂,加入到废玻璃粉末中烧结制备成透辉石-钠长石玻璃陶瓷。研究了析晶促进剂的组成和加入量对玻璃陶瓷析晶和性能的影响。结果表明,在烧结过程中,析晶促进剂和玻璃发生反应,析出透辉石和钠长石。析晶促进剂的组成和加入量对反应析晶有一定影响,随析晶促进剂加入量的增加,玻璃陶瓷密度和强度先增后降,存在一最佳加入量,这时烧结的玻璃陶瓷有较高的密度和强度。 相似文献
3.
反应析晶烧结法制备硅灰石玻璃陶瓷 总被引:1,自引:1,他引:0
本文提出了一种直接利用废玻璃制备硅灰石玻璃陶瓷的新工艺:反应析晶烧结法。将高岭土和碳酸钙为主要原料合成的析晶促进剂加入到废玻璃粉末中烧结,通过两者间的反应析出硅灰石。研究了析晶促进剂含量和烧结温度对硅灰石玻璃陶瓷的组织、烧结和性能的影响,结果表明:随着析晶促进剂含量的增加,玻璃陶瓷的体密度和开孔隙率增加,强度先增后降。提高烧结温度促进反应析晶,并导致玻璃陶瓷的体密度、开孔隙率和强度降低。析晶促进剂含量为15%,烧结温度为850℃时,制得的硅灰石玻璃陶瓷的力学性能最佳。 相似文献
4.
《Journal of the European Ceramic Society》2007,27(6):2415-2422
Glass obtained from melting a mixture of industrial wastes (panel glass from dismantled cathode ray tubes, mining residues from feldspar excavation and lime from fume abatement systems of the glass industry) has been employed for manufacturing micro- and macro-cellular sintered glass-ceramics. Micro-cellular glass-ceramics, with a closed porosity, were prepared by the direct foaming of the glass mass, determined by viscous flow sintering of fine powders (<37 μm), due to addition of a SiC-based waste (from the polishing of glass articles). The surface crystallization of glass, upon sintering, limited the porosity (being about 50%), but imparted a remarkable crushing strength to the products (up to about 80 MPa), useful for construction applications. Micro- and macro-cellular glass-ceramics, with an open porosity and very low relative density (from 40 to less than 10%), were prepared by the sintering of fine glass powders mixed with sacrificial poly-methyl methacrylate microbeads or deposited on sacrificial poly-urethane sponges. The crystallization, besides imparting a good mechanical strength, allowed the maintenance of the open-celled morphology, useful for filtering applications. 相似文献
5.
Bioactive glass and glass-ceramics in the system CaO-MgO-SiO2-P2O5 have been prepared by the sol-gel and high temperature sintering techniques. The obtained samples were characterized by thermogravimetric and differential thermal analysis (TG/DTA), N2-adsorption measurement, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In vitro bioactivity tests were also conducted in simulated body fluid (SBF). The studies of crystallization kinetics under non-isothermal conditions showed the activation energy for crystallization to be 381 kJ/mol and the crystallization mechanism gradually changed from three-dimension growth to two-dimension crystallization with the increase of heating rate. Sintering temperature had great influence on the samples texture and structure. In addition, the apatite-formation on glass and glass-ceramics was confirmed by in vitro tests, and crystallization decreased the samples bioactivity. 相似文献
6.
《Journal of the European Ceramic Society》2006,26(15):3335-3341
Glass obtained from melting a mixture of industrial wastes (panel glass from dismantled cathode ray tubes, mining residues from feldspar excavation and lime from fume abatement systems of the glass industry) has been employed for the production of sanidine-based glass-ceramics. The glass-ceramics were developed by a sintering treatment with concurrent crystallization, from fine powders (<37 μm), at a relatively low temperature (880 °C). The enhanced nucleating activity of glass surfaces likely promoted the formation of sanidine, hardly found in glass-ceramics, as the main crystal phase. Due to the achieved mechanical properties (bending strength of about 120 MPa, Vickers’ microhardness exceeding 7 GPa) and aesthetic appearance, resulting from a compact and homogeneous microstructure, the obtained sanidine glass-ceramics may find applications as construction materials. 相似文献
7.
以高铝粉煤灰提铝硅钙尾渣为主要原料,采用烧结法制备了硅灰石微晶玻璃。利用DTA、XRD和SEM分析方法研究了热处理制度、硅钙渣用量对微晶玻璃的晶化过程、显微结构及物化性能的影响。结果表明:核化时间与晶化时间的延长有助于硅灰石晶体的定向生长与紧密排列,对微晶玻璃的力学性能影响显著,而晶化温度与核化温度的影响则相对较小;随着硅钙渣的用量增加,微晶玻璃中硅灰石的析出能力增强,当其用量为70.98%,在800℃下核化热处理90 min,920℃晶化处理90 min时,可制备出单一晶相的硅灰石微晶玻璃。 相似文献
8.
9.
《Ceramics International》2020,46(13):20633-20639
A reliable method for fabricating soda lime glass-ceramics by selective laser sintering was demonstrated. The effect of the ratio of glass powder to epoxy resin and sintering process on the properties and microstructure of glass-ceramics was investigated. Research shows that: with the improvement of glass powder proportion, sintering shrinkage rate declined and mechanical strength could be improved gradually. When the mass ratio of glass powder and epoxy resin powder was 18:1 and heat-holding at 740 °C for 3 h, the shrinkage rate of the sample was 21.11% and the bending strength reached 95.45 MPa. Therefore, this research laid a foundation for 3D printing to fabricate high performance and complex structure glass-ceramics. 相似文献
10.
《Ceramics International》1997,23(5):401-407
The α-cordierite and β-spodumene glass-ceramics containing B2O3, P2O5, and/or TiO2 were produced in a bar shape by hot pressing and crystallization heat treatments of glass powders. Various physical properties of the glass-ceramics were examined. The α-cordierite glass-ceramics showed intrinsic high mechanical property values, whereas the β-spodumene glass-ceramics showed rather low ones. The relatively low density in β-spodumene glass-ceramics would lead to the low mechanical property values. This low density in the β-spodumene glass-ceramics would result from a possible premature crystallization which might hinder a completion of sintering of the matrix. The glass-ceramics without TiO2 showed slightly higher mechanical properties than those with TiO2. This difference would result from slightly higher density in the glass-ceramics without TiO2. 相似文献
11.
Sintering Behavior and Properties of Iron-Rich Glass-Ceramics 总被引:1,自引:0,他引:1
Alexander Karamanov Giuliana Taglieri Mario Pelino 《Journal of the American Ceramic Society》2004,87(8):1571-1574
Iron-rich glass-ceramics were obtained by the sintering of two glass powders, labeled G1 and G2, at heating rates of 5° and 20°C/min followed by an isothermal step in the 850°–1050°C temperature interval. The sintering process was evaluated by the linear shrinkage; the closed porosity was estimated by density measurements; the structure and the morphology of the glass ceramics were observed by scanning electron microscopy. The bending strength, the Young modulus, and Vickers hardness of the glass-ceramics materials were evaluated. The results showed that the sintering process and morphology of the glass-ceramics depends on the amount of magnetite and pyroxene formed. With a low percentage of crystal phase formed (25%–30% typical of G1) the structure is characterized by closed porosity; at higher crystallization (45%–50% typical of G2) open porosity is mainly formed. The properties of the glass-ceramics were not influenced by the heating rate but improved with an increase in the degree of crystallization. 相似文献
12.
《Ceramics International》2023,49(5):7737-7745
Glass-ceramics without nucleating agents usually undergo surface crystallization, which deteriorates the overall performance of the products. In this paper, we evaluated the effects of the metastable MgAl2Si3O10 crystalline phase on the crystallization behavior of a MgO–Al2O3–SiO2 (MAS) glass without nucleating agents and mechanical properties of the glass-ceramics obtained. The results demonstrated that the precipitation of metastable MgAl2Si3O10 crystallites promotes the crystallization mechanism transformed from surface crystallization into volume crystallization with two-dimensional crystal growth. Furthermore, the grain size of MgAl2Si3O10 near the surface of the prepared glass-ceramics was larger than that of MgAl2Si3O10 inside, which helps to generate compressive stress and improves its mechanical properties. The glass-ceramics containing metastable MgAl2Si3O10 phase exhibited an enhanced hardness in the range of 7.6 GPa–9.5 GPa for indentation loads ranging from 2.94 N to 98 N, and indentation size effect behavior was observed in Vickers hardness tests of both MAS glass and glass-ceramics. The load-independent hardness values for MAS glass and glass-ceramics were reliably evaluated by the modified proportional specimen resistance (MPSR) model of 7.1 GPa and 7.6 GPa, respectively, with a high correlation coefficient of more than 0.9999. This work reveals the unexploited potential of the metastable phase in improving the crystallization ability and mechanical properties of glass-ceramics. 相似文献
13.
The densification and crystallization behaviors of MgO-B2O3-SiO2 (MBS) glass with various amounts of TiO2 additions (0-10 wt.%) were investigated by means of thermal analysis, X-ray powder diffraction and scanning electron microscopy. A microwave dielectric characterization was performed in order to evaluate the suitability of MBS glass-ceramics as a low-permittivity dielectric substrate. The densification of the MBS glass started below 700 °C. The main crystalline phases of Mg2B2O5 and MgSiO3 appeared at 800 and 950 °C, respectively. The Mg3TiB2O8 and TiB0.024O2 phases additionally crystallized in TiO2-added MBS glass-ceramics at 1000 °C. The permittivity increased from 6.1 in pure MBS glass to 6.9 in MBS glass with 10 wt.% of TiO2. The addition of TiO2 enhanced the crystallization and consequently increased the Qxf-values of the MBS glass (11 300 GHz) up to 16 500 GHz. The improvement of the Qxf-values became the most evident at 1050 °C. Dense MBS glass-ceramics sintered at 850 ≤ T ≤ 950 °C exhibited Qxf-values of 5000-8000 GHz (at ∼12 GHz), which are comparable with the values of CaO-B2O3-SiO2-based glass-ceramics. 相似文献
14.
Hangmi Wu Wenxin Teng Xin Feng Jiangling Li 《International Journal of Applied Ceramic Technology》2024,21(2):844-854
Ti-bearing blast furnace slag is a typical silicate material, which can be an important component for the preparation of silicate-based glass-ceramics. Quartz-based waste glass is commonly used as an additive to adjust the basicity of slag-based glass-ceramics. In this study, the quartz-based waste glasses were added to the Ti-bearing blast furnace slag to prepare the mixed solid waste glass-ceramics. The effects of waste glass content and heat treatment temperatures on the crystallization and performances of the prepared glass-ceramics were investigated. The results showed that as the waste glass content increased, the crystallization ability of the glass was weakened. Fassaite and nepheline were identified as the dominant crystalline phases in the prepared glass-ceramics and mainly featured a combination of both massive and dendritic forms. With increasing the heat treatment temperatures, the size of dendritic crystals first increased and then decreased. The optimal experimental conditions were identified as a waste glass content of 45%, a crystallization temperature of 900°C, and a nucleation temperature of 730°C. Under these conditions, the prepared glass-ceramics exhibited good crystalline phase distribution and excellent mechanical properties, including a Vickers hardness of 991.67 MPa and a flexural strength of 89.81 MPa. All the prepared solid waste-based glass-ceramics exhibited excellent chemical durabilities. 相似文献
15.
16.
《Ceramics International》2023,49(16):26934-26942
The bottom ash (OIBA) generated from the incineration of hazardous oil sludge is classified as a hazardous waste. In this work, the OIBA was applied as raw material to prepare SiO2-Al2O3-CaO system glass-ceramics by melt-sintering with the addition of waste glass wool (GW). The effects of basicity (CaO/SiO2 ratio, 0.52-1.05) and sintering temperature (900–1050 °C) on the crystallization kinetics, properties, microstructure, leaching concentrations of heavy metals and potential toxicity of glass-ceramics were investigated. The results showed that the crystallization pattern was two-dimensional crystallization, and with the decrease of basicity, the main crystalline phase evolved from gehlenite to diopside. And the glass-ceramics with basicity of 0.88 and sintering temperature of 950 °C exhibited the best comprehensive properties, including density (2.72 g/cm3), water absorption (0.06%), compressive strength (452.45 MPa) and chemical corrosion resistance. In addition, the reduction of heavy metal leaching concentration indicates that produced glass-ceramics showed excellent solidification effect on heavy metals, the low toxicity of glass-ceramics leaching solution to the wheat seeds and Artemia suggests the environmental protection characteristics of OIBA-based glass-ceramics. These findings proved that the glass-ceramics produced by OIBA and GW could be a promising method to dispose hazardous waste with preparing high value-added construction materials. 相似文献
17.
In order to obtain high-strength anorthite glass-ceramics, K2O–CaO–Al2O3–SiO2 quaternary glass and relevant glass-ceramics were prepared and investigated. The results show that anorthite along with kalsilite or leucite was precipitated from the parent glass. Kalsilite crystals were formed firstly and then converted into leucite through reacting with SiO2 in the glass phase. The morphology of the crystals was dependent on the heat-treatment temperature. Column crystals were transformed into fine granular grains when the sintering temperature changed from 900 °C to 1100 °C. The activation energy (Eα) and avrami constant (n) were also calculated as 463.81 KJ/mol and 3.74 respectively, indicating that bulk nucleation and three-dimensional crystal growth were the dominating mechanisms in the temperature range 1000–1100 °C. The maximum value of the flexural strength for the glass-ceramics containing leucite was 248 MPa and the coefficient of thermal expansion (CTE) was in the range 5.69~11.94×10−6 K−1. The leucite is the main reason for the high CTEs and high flexural strength of glass-ceramics. 相似文献
18.
The influence of barium oxide, heat treatment time and temperature on the crystallization, microstructure and mechanical behavior of the system Bax·K1−2x·Mg3·Al·Si3O10·F2 (where x = 0.0, 0.3 and 0.5) was investigated in order to develop novel, high strength and machinable glass-ceramics. Three glasses were prepared and characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscope (SEM) techniques and some mechanical testing methods.The crystallization kinetics of glass-ceramics was also studied. Activation energy and Avrami exponent calculated for the crystallization peak temperature (Tp) of three different glass batches. The Vickers hardness decreased slightly on formation of the potassium fluorophlogopite and barium fluorophlogopite phases, but decreased significantly on formation of an interconnected ‘house of cards’ microstructure. 相似文献
19.
The production of glass ceramics (GCs) with theoretical anorthite–diopside (An–Di) weight ratios of 60/40, 50/50 and 45/55 via sintering and crystallization of glass powder compacts was investigated at different temperatures between 800 and 950 °C. The investigated compositions are located in the cross-section of the ternary fluorapatite–An–Di system close to An–Di binary joint, with constant fluorapatite content of 4.8 wt.%. Two different groups of glass powders, with mean particle size of 2 and 10 μm, were used. The experimental results showed that sintering is almost complete at 800 °C, preceding crystallization, which takes place via surface crystallization mechanism. The properties values of the produced GCs, which are the best for the composition close to An–Di eutectic line, are discussed with respect to the evolution of crystalline phases and the microstructure over increasing firing temperature. Under the technology perspective, the investigated processing route is significantly superior in comparison to the attempts reported in earlier studies. 相似文献