反应析晶烧结法制备透辉石-钠长石玻璃陶瓷

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。     

氟化钙对钠钙玻璃反应析晶制备玻璃陶瓷性能的影响

用X射线衍射、Fourier变换红外光谱、扫描电子显微镜研究了不同氟化钙加入量的钠钙玻璃粉末在烧结过程中的反应析晶。结果表明:未加入氟化钙时,以钙铝黄长石作为析晶促进剂,在850℃反应析晶生成硅灰石玻璃陶瓷;当析晶促进剂含量低于15%(质量分数,下同)时,添加6%氟化钙在850℃反应析晶生成枪晶石玻璃陶瓷。随氟化钙添加量增加,制备的枪晶石玻璃陶瓷气孔率逐渐增大,体积密度减小,抗弯强度降低。当氟化钙添加量为6%时,制得的枪晶石玻璃陶瓷抗弯强度达到68MPa。     

废玻璃粉反应析晶制备枪晶石玻璃陶瓷性能研究

将废玻璃粉与钙铝黄长石、氟化钙混合,使用反应析晶烧结法制备出主晶相为枪晶石的玻璃陶瓷.研究了钙铝黄长石和氟化钙含量、烧结温度对玻璃陶瓷晶相、相对密度、烧结率、吸水率及力学性能的影响.结果表明,加入15％(质量分数,下同)钙铝黄长石和6％氟化钙时,玻璃陶瓷中析出的主晶相为枪晶石.提高钙铝黄长石或氟化钙含量有硅灰石析出.在850℃和900℃烧结后,玻璃陶瓷的相对密度和烧结率都随钙铝黄长石或氟化钙含量的升高而降低,其中,提高氟化钙含量比提高钙铝黄长石含量对烧结阻碍作用更大;吸水率随钙铝黄长石或氟化钙含量的升高而升高;玻璃陶瓷的强度随钙铝黄长石或氟化钙含量提高而降低,随温度升高而变大.和850℃相比,900℃烧结后,枪晶石玻璃陶瓷的强度最大可提高51％.     

生物玻璃的烧结与析晶

利用玻璃的烧结收缩,结合差热分析和X射线衍射分析,研究了CaO-SjO_2-P_2O_5系统生物玻璃的烧结和析晶动力学。确定它的烧结机制主要是粘性流动烧结。A玻璃和Ⅰ-2玻璃的烧结活化能分别为540kJ/mol和476kJ/mol。析晶相是磷灰石和硅灰石。A玻璃和Ⅰ-2玻璃的析晶表观活化能分别约为480kJ/mol和390kJ/mol。通过分析烧结温度、Na_2O含量对烧结和析晶的影响,选择了合适的烧结条件,控制烧结和析晶程度,获得了既有足够的自身强度,又有一定的结合强度的多孔玻璃陶瓷。     

烧成温度对反应析晶法制备可加工氟闪石玻璃陶瓷的影响

将氟云母晶体粉末与普通窗玻璃粉末直接混合后烧结制备出可加工氟闪石玻璃陶瓷,与传统的玻璃陶瓷制备工艺不同的是:氟闪石晶体不是从母相玻璃中直接析出,而是通过氟云母和玻璃间的反应析出.用X射线衍射、扫描电镜分析了氟闪石的反应析晶和玻璃陶瓷的组织,研究了烧成温度对玻璃陶瓷密度、可加工性和抗压强度的影响.结果表明:随着烧成温度的提高,氟闪石反应析晶速度加快,玻璃陶瓷加工性得到改善,但密度和强度下降.900℃烧结2h制备的玻璃陶瓷具有良好的可加工性和较高的强度.     

添加氟化物对硅灰石玻璃陶瓷性能的影响

以钙铝黄长石、废玻璃粉为主要原料,分别添加MgF2、BaF2及复合氟化物,用反应析晶烧结法制备硅灰石玻璃陶瓷.使用X射线衍射(XRD)、扫描电子显微镜(SEM)对样品的物相和形貌进行表征.对添加不同氟化物制备的硅灰石玻璃陶瓷进行了密度、收缩率、气孔率、吸水率、抗弯强度、抗压强度等性能测试.结果表明,添加MgF2、BaF2或复合氟化物制备的玻璃陶瓷主晶相均为硅灰石.添加MgF2可促使硅灰石玻璃陶瓷大量析晶,密度较低,吸水率和气孔率均较高,抗压强度大大降低.添加BaF2或复合氟化物具有较低的吸水率和气孔率,较高的密度,以及较高的抗弯强度和抗压强度.添加复合氟化物后可通过玻璃陶瓷的自收缩作用实现其烧结致密化,当添加5％MgF2与5％BaF2后,制得的硅灰石玻璃陶瓷体积密度2.4322 g/cm3,相对密度90.93％,气孔率0.27％,吸水率0.06％,抗弯强度54 MPa,抗压强度239 MPa.     

废玻璃降低日用陶瓷烧成温度的研究

研究废玻璃降低日用陶瓷烧成温度的可能性.以普通陶瓷坯料为基体,外加不同粒度的废玻璃并调整废玻璃的掺加量,经干燥成型制备坯体,干燥后在1100℃～1250℃烧结.通过测定吸水率、电子扫描电镜观察断面形貌确定其烧结程度及致密度,测试其强度进行比较.实验结果表明,陶瓷坯体掺入废玻璃不仅能降低烧成温度还能增加强度,添加9%、120目废玻璃粉的坯体强度增加16.73%.     

SiO_2-Al_2O_3-MgO-F系玻璃陶瓷的烧结析晶──烧结工艺对组织和性能的影响

系统探讨了ＳｉＯ２－ＭｇＯ－Ａｌ２Ｏ３－Ｆ系玻璃粉体的烧结析晶行为。结果表明：烧结温度和时间对玻璃陶瓷的显微组织、烧结密度和硬度都有显著的影响。烧结温度的提高和烧结时间的延长有利于烧结和析晶过程的进行,但温度过高将导致析出的晶体发生重熔。由于析晶和烧结同时进行,密度和硬度呈现不一致的变化趋势。     

生物玻璃的烧结与折晶

利用玻璃的烧结收缩，结合差热分析和Ｘ射线衍射分析，研究了ＣａＯ－ＳｉＯ２－Ｐ２Ｏ５系统生物玻璃的烧结和折晶动力学。确定它的烧结机制主要是粘性流动烧结。Ａ玻璃和Ⅰ－２玻璃的烧结活化能分别为５４０ｋＪ／ｍｏｌ和４７６ｋＪ／ｍｏｌ。析晶相是磷灰石和和硅灰石。Ａ玻璃和Ⅰ－２玻璃的析晶表观活化能分别约为４８０ｋＪ／ｍｏｌ和３９０ｋＪ／ｍｏｌ。通过分析烧结温度、Ｎａ２Ｏ含量对烧结和析晶的影响，选择了合适的烧结     

利用废岩棉制备高性能泡沫玻璃陶瓷的实验研究

以工业垃圾废岩棉和废玻璃为原料，以CaCO₃为发泡剂制备出高强度泡沫玻璃陶瓷。研究了废岩棉和废玻璃的添加量及烧结温度对泡沫玻璃陶瓷材料性能的影响。结果表明：随着废岩棉添加量的增加和烧结温度的提高，熔体黏度会降低，不利于气泡结构的稳定；在废岩棉添加量为40%、750℃烧结温度下得到的样品容重为0.54 g/cm³、孔隙率为62.5%、抗压强度为4.76 MPa；样品主晶相为亚硅酸钙和石英晶相，加入TiO₂作为晶核剂后主晶相改变为榍石；TiO₂掺量为10%时，在750℃烧结20 min更经济，所得样品容重为0.82 g/cm³、孔隙率为50%、抗压强度为7.76 MPa。     

Sintering and reactive crystal growth of diopside-albite glass-ceramics from waste glass

Diopside-albite glass-ceramics were fabricated by sintering the powder mixtures of crystallization promoters and waste glass. Two kinds of promoters were synthesized using kaolin clay, talc and chemical reagents. The crystalline phases were formed by a reactive crystallization between promoters and glass during sintering. The effect of promoter components, additions and sintering temperatures on the crystallizing and densifying behavior, microstructures and mechanical properties of glass-ceramics was investigated. The results showed that the higher densities and better mechanical properties were obtained for the glass-ceramics with 12-15% crystallization promoters sintered at 950 °C for 2 h.     

Micro- and macro-cellular sintered glass-ceramics from wastes

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.     

Sinterability,microstructure and compressive strength of porous glass-ceramics from metallurgical silicon slag and waste glass

Porous glass-ceramics have been prepared by the direct sintering of powder mixtures of metallurgical silicon slag and waste glass. The thermal behavior of silicon slag was examined by differential thermal analysis and thermogravimetry to clarify the foaming mechanism of porous glass-ceramics. The mass loss of silicon slag below 700 °C was attributed to the oxidation of amorphous carbon from residual metallurgical coke in the silicon slag, and the mass gain above 800 °C to the passive oxidation of silicon carbide. The porosity of sintered glass-ceramics was characterized in terms of the apparent density and pore size. By simply adjusting the content of waste glass and sintering parameters (i.e. temperature, time and heating rate), the apparent density changed from 0.4 g/cm³ to 0.5 g/cm³, and the pore size from 0.7 mm to 1.4 mm. In addition to the existing crystalline phases in the silicon slag, the gehlenite phase appeared in the sintered glass-ceramics. The compressive strength of porous glass-ceramics firstly increased and then decreased with the sintering temperature, reaching a maximal value of 1.8 MPa at 750 °C. The mechanical strength was primarily influenced by the crystallinity of glass-ceramics and the interfaces between the crystalline phases and the glassy matrix. These sintered porous glass-ceramics exhibit superior properties such as light-weight, heat-insulation and sound-absorption, and could found their potential applications in the construction decoration.     

Sintering Behavior and Properties of Iron-Rich Glass-Ceramics

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.     

珍珠岩制备单一α-堇青石微晶玻璃及其性能

以珍珠岩为主要原料制备了单相α-堇青石微晶玻璃.采用DSC、XRD及FESEM分别研究了微晶玻璃的烧结和晶化行为、晶相组成及显微结构.探讨了烧结温度和SiO2含量对微晶玻璃晶相、显微结构及性能的影响.结果表明,随着烧结温度升高,微晶玻璃中μ-堇青石逐渐减少并转变成α-堇青石,微晶玻璃的孔隙率减少.随着SiO2含量升高,α-堇青石晶相析出温度先降低后增高,微晶玻璃的密度及抗折强度先增大后减小,介电性能变差.当Mg∶Al∶Si=2∶2∶5.95时经900 ℃烧结6 h制得单一α-堇青石微晶玻璃,并具有高抗折强度(116 MPa),低介电常数(5.72,10 MHz),低介电损耗(0.0059,10 MHz),与Si相匹配的热膨胀系数(2.91×10-6 K-1),可以用作低温共烧陶瓷材料.     

热处理温度对磷渣-煤矸石微晶玻璃结构和性能的影响

以磷渣和煤矸石为原料,采用一步烧结法制备了性能优良的CaO?Al2O3?SiO2(CAS)系微晶玻璃,用差示扫描量热法(DSC),X射线衍射(XRD)和扫描电子显微镜(SEM)等对其进行分析和表征,研究了热处理温度对微晶玻璃晶相组成、微观结构和宏观性能的影响规律。结果表明,固废利用率达100%,微晶玻璃性能良好;以磷渣和煤矸石为原料在1250℃下熔融2 h、于850℃热处理保温2 h可制备主晶相为假硅灰石Ca3(Si3O9)的微晶玻璃,其抗折强度、显微硬度和体积密度分别为74.4 MPa,566.9 HV和2.75 g/cm3。随热处理温度升高,微晶玻璃主晶相由Ca3(Si3O9)相转变为硅灰石CaSiO3相,晶体形态由球状向针状、短柱状改变,对提高微晶玻璃抗折性能有利,而显微硬度和体积密度均先增加后降低。     

Preparation and properties of porous ceramic aggregates using electrical insulators waste

In this paper, porous ceramic aggregates were prepared by electrical insulators waste (EIW). Effects of sintering temperature and content of EIW on the aggregates’ properties such as bulk density, and apparent porosity, total porosity, and cold crushing strength were investigated. With increasing sintering temperature and content of EIW, bulk density and cold crushing strength of the aggregates increased, apparent porosity and total porosity decreased. Based on these results, total porosity of specimens in group B sintered at 1200 °C is 62.0%, cold crushing strength is 35.3 N, and thermal conductivity is 0.165 W/(m K) at 300 °C. Comprehensive properties of specimens can be optimized by adjusting sintering temperature. Meanwhile, strength variation resulted from the combined effects of phase transformation and matrix densification under different sintering temperatures.     

电解锰渣－废玻璃低温烧结制备陶瓷砖的研究

以电解锰渣和废玻璃为主要原料,采用低温烧结法制备陶瓷砖,探讨了烧结温度、电解锰渣及废玻璃的含量对陶瓷砖基本性能的影响。结果表明,随着烧结温度的升高,陶瓷砖吸水率先减小后增大,体积密度先增大后减小;随着锰渣含量的增加,陶瓷砖的吸水率逐渐增大,体积密度逐渐减小;随着玻璃含量的增加,陶瓷砖的吸水率逐渐减小,体积密度逐渐增大。40 g陶 瓷原料,当锰渣的添加量为32%（质量分数）、玻璃的添加量为10 g、烧结温度为900 ℃时,得到的陶瓷砖的吸水率最低、体积密度最大。     

Preparation and properties of the glass-ceramics from low Ti-bearing blast furnace slag and waste glass

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.