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％.     

Crystallization of Anorthite-Seeded Albite Glass by Solid-State Epitaxy

Stoichiometric albite glass (NaAlSi₃O₈) was seeded with 5 wt% crystalline anorthite (CaAl₂Si₂O₈) to make albite glass-ceramics. The epitaxial crystallization of the albite glass to the glass-ceramics was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). High albite was observed as the major crystallization product over the temperature range of 800–1200°C. No crystalline albite could be crystallized from pure albite glass without seeds. Small amounts of nepheline (NaAlSiO₄), however, crystallized along with albite after heat treatments at temperatures lower than 1000°C. The platelike microstructure of albite crystals was revealed in the seeded glasses. The albite blades grew epitaxially from the anorthite seeds, and the Ca content decreased in the direction away from the seeds. The degree of crystallization and the grain size were dependent upon the heat treatment conditions. By increasing the particle size of the seed, the crystallization process was retarded and the resultant microstructure was degraded. The seeding efficiency was also lowered by adding nonisostructural hexagonal anorthite seeds which produced less albite but more nepheline crystals. Crystallization of albite glass by seeding with 5 wt% anorthite is much greater than with the surface nucleation which takes place in a homogeneous 95 wt% albite + 5 wt% anorthite glass.     

添加V2O5对SiO2-Al2O3-MgO系微晶玻璃析晶的影响

为了探讨V2O5对SiO2-Al2O3-MgO系微晶玻璃的析晶的影响,制备了添加质量分数为8%V2O5的玻璃.用扫描电子显微镜(SEM)和X射线衍射(XRD)与电子探针(EPMA)等技术研究了玻璃的析晶特征.结果表明:与未添加V2O5的试样相比,V2O5加入促进了玻璃在较低的温度下析晶.在630℃保温3h后,在玻璃中已开始析出莫来石晶体.随着析晶温度的提高和保温时间的延长,在试样中同时析出莫来石和云母晶体,云母晶体的尺寸和数量逐渐提高,晶体所占体积百分数逐渐增大,而莫来石晶体的尺寸变化不明显,最终形成均匀分布的云母/莫来石复合体.当析晶温度达到1050℃时,玻璃中晶体的析出反而减少,晶体的相互交错度与所占的体积百分数均有所降低.EPMA结果显示试样析晶后,V2O5留在残余玻璃中,表明V2O5没有参与晶体的直接形核,而是以网络外体的形式存在于玻璃体系中,削弱了玻璃的结构,导致晶体析出温度降低.     

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。     

Studies of the Crystallization of Antimony-Containing Slag Glass-Ceramic

The paper explains the necessity and basic principles of fabricating slag glass-ceramic based on special local antimony-containing slag. A CaO-Al₂O₃-SiO₂ three-component phase diagram was used to plan a base glass composition, to which four selected nucleating agents, Cr₂O₃, ZrO₂, P₂O₅, and TiO₂, were added separately. Studies focused on their roles in the crystallization of the present slag glass system with the aid of differential thermal analysis, X-ray diffractometery, and scanning electron microscopy. Comparisons showed that the four nucleating agents behaved differently and therefore exerted different influences on crystallization. TiO₂ proved to be the best one, and its optimal concentration was 10 wt%.     

反应析晶烧结法制备硅灰石玻璃陶瓷

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。     

Application of Seeded Membrane Distillation Crystallization for Zero Liquid Discharge

Zero liquid discharge (ZLD) is a crucial requirement in industrial operations concerned with water scarcity and environmental protection. This study investigates the feasibility of using membrane distillation combined with crystallization (MDC) as a potential solution for ZLD. High-saline NaCl solutions were used to evaluate the performance of a seeded MDC system, which demonstrated excellent recovery rates for both water (over 95 %) and salt (over 95.5 %). The presence of seeding crystals in the MDC system was found to inhibit membrane wetting. The MDC system achieved an average thermal efficiency of 61.5 %, showcasing its potential for long-term processes. These results indicate that introducing seed crystals to the membrane's feed side enhances the MDC system's viability as a promising solution for ZLD. Additionally, the MDC system offers the prospect of high water and salt recovery, making it a sustainable approach to wastewater treatment and water reclamation.     

钙钛锆石玻璃陶瓷体的晶化和抗浸出性能

以SiO2、A12O3、B2O3、CaO、TiO2和ZrO2为原料,加入3％CeO2（质量分数,下同）作为模拟核素,利用熔融法制备钙钛锆石基玻璃陶瓷体,对含锕系元素的放射性废物进行固化处置。通过X射线衍射仪和场发射扫描电子显微镜等对热处理后玻璃陶瓷体进行表征。以电感耦合等离子体质谱测试玻璃陶瓷体抗浸出性能。结果表明：在晶化温度为1050℃,B203掺量为12．5％时,玻璃陶瓷体中低质量分数的TiO2和ZrO2更易参与生成钙钛锆石晶体,但固化体中仍有其他晶相存在;在同样晶化温度下,B203掺量为8．33％时对玻璃陶瓷体形成钙钛锆石单一晶相较为有利,且具有较好的抗浸出性能,其中Ce在产品一致性测试法下元素标准化浸出率7d后维持在10^-6数量级,固化效果明显。     

以Fe2O3作晶核剂的尾矿玻璃陶瓷晶化研究

运用差热分析（ＤＴＡ）、扫描电镜（ＳＥＭ）、Ｘ射线衍射（ＸＲＤ）、能谱分析（ＥＤＡＸ）等测试手段,研究了以 Ｆｅ２Ｏ３作晶核剂时ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２系统尾矿玻璃陶瓷析晶特征。结果表明,Ｆｅ２Ｏ３降低了玻璃整体析晶温度,并在热处理时诱导玻璃分组,从而促进成核和晶相生长。合理控制热处理条件可获得性能良好的尾矿玻璃陶瓷材料。     

Crystallization Measurements Using DTA Methods: Applications to Zerodur®

Differential thermal analysis (DTA) experiments described herein apply two methodologies by which to estimate absolute nucleation rates and/or temperature dependencies using a low-expansion, commercially relevant, multicomponent glass-ceramic as a test material. In particular, the Marotta and the Ray et al. methods were applied to Zerodur® and both provided valuable insight into a relatively complicated crystallization process. Previous nucleation and crystal growth rate data were used in a comparative manner. Although the Marotta method accurately predicted the maximum nucleation temperature, the nature of the technique precluded an estimation of absolute nucleation rates. The Ray et al. technique provided reasonable nucleation rates, but failed to provide useful estimates of the number of quenched-in nuclei, in part because of a substantial "blank" contribution coming from additional, unwanted nucleation during heating and cooling stages of the DTA technique.     

CaF2含量对CaO-SiO2-R2O-F系微晶玻璃晶化行为的影响

采用烧结法制备了CaO-SiO_2-R_2O-F(R=Na, K)系微晶玻璃,并结合XRD、DTA、SEM等测试方法,探讨了CaF_2含量对CaO-SiO_2-R_2O-F系微晶玻璃晶化行为的影响.结果表明:添加适量的CaF_2能有效地促进微晶玻璃的析晶.在一定热处理制度下,制备出的微晶玻璃内含大量互锁的板条状晶体和针状晶体,主晶相为硅碱钙石和Frankamenite(一种富含氟的硅碱钙石).随着CaF_2含量的增加,晶体的含量逐渐提高,晶体数量逐渐增大,尺寸逐渐减小.     

SiO2-Al2O3-CaO-MgO-Fe2O3-ZrO2-F系玻璃陶瓷的析晶

应用扫描电子显微镜、X射线衍射及示差扫描量热法等技术研究了一种SiO2-Al2O3-CaO-MgO-Fe2O3-ZrO-F玻璃陶瓷析晶特征和组织形貌.结果表明:玻璃转变温度为725 ℃左右,在730 ℃后形成了分布均匀的孔状非晶态分相现象.在第一放热峰温度(820 ℃)析晶时,玻璃样品为表面析晶,析出晶体为钙长石(CaAl2Si2O8)和硅灰石(CaSiO3).从表面向内部分别形成枝状晶体、枝状晶体和粒状晶体、粒状晶体三层不同的表面析晶形态.在1040 ℃保温后,玻璃样品中表面析晶和整体析晶共存,析出晶相均以钙长石为主.     

Al2O3对R2O-CaO-SiO2-F系统微晶玻璃结构及析晶的影响

R2O-CaO-SiO2-F系统微晶玻璃析晶过程较为复杂,能析出多种晶相,导致性能发生改变。为获得预期的性能,必须对母体玻璃结构和析晶过程进行控制。而Al2O3质量分数的改变对母体玻璃结构和析晶会产生深远的影响,因此本文采用XRD、SEM、IR等测试分析方法,研究Al2O3对微晶玻璃结构和析晶过程的影响。结果表明:铝离子以四配位参与到玻璃的硅氧网络结构中,随着Al2O3引入量的增大,母体玻璃的网络结构得到加强。当氧化铝质量分数为2.5%时,微晶玻璃晶化后析出氟化钙和a-硅碱钙石晶相,当氧化铝质量分数增大至3.5%和4%时,微晶玻璃析出的晶相转变为氟化钙和硬硅钙石,氧化铝质量分数继续升高至4.5%时,微晶玻璃析出的晶相转变为氟化钙、硬硅钙石和a-硅碱钙石晶相。     

聚合物在取向聚合物薄膜上的附生结晶研究进展

总结了近年来以取向聚合物为基底的聚合物附生结晶的部分研究成果,重点综述了聚合物附生结晶的机理及晶格匹配、链段规整度、结晶动力学、二次成核等因素对聚合物附生结晶的影响,并对其今后的发展进行了展望。     

Seeded Crystallization of Leucite

The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano-crystalline leucite was investigated by X-ray diffraction and non-isothermal differential thermal analysis. The nano-crystalline leucite was prepared by high-energy milling of high-purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.     

Effect of Heat-Treatment Temperature on the Properties of a Lithium Aluminosilicate Glass

The effects of isochronal heat treatments on the properties of a lithium aluminosilicate glass have been measured. Heat treatment of the base glass at temperatures between 700° and 1100°C initially results in phase separation of the glass, followed by the formation of β-quartz solid solution ( ss ) at about 850°C. The β-quartz( ss ) converts to β-spodumene in the temperature range between 950°C and 1000°C. The dependence of the properties of the material on the heat-treatment temperature is controlled by phase separation below 850°C, by the rapid crystallization of β-quartz( ss ) between 850°C and 900°C, and by the lack of change in morphology with heat treatment above 900°C. The effects of heat treatment on the properties of this material are explained on the basis of the changes in the composition and morphology of the residual amorphous and crystalline phases.     

阳极键合用微晶玻璃的热处理温度研究

阳极键合技术在几十年来得到了很大的发展。随着其使用范围的扩大和对键合强度要求的提高,对基片材料提出了新的要求。微晶玻璃是一种性能优异的材料,如果能与不锈钢进行键合,将在微机电系统得到广泛的应用。论文在前期工作的基础上分别对微晶玻璃的核化和晶化温度进行了系统研究,通过XRD,SEM及相关的测试手段,分析讨论了热处理温度对主晶相、晶粒尺寸大小、析晶程度及其相关性能的影响。实验结果表明,样品的主晶相为Li2SiO3,合适的核化温度范围为450~630℃,晶化温度范围为670~760℃,样品的最大抗折强度为95.38MPa。     

Effect of Crystallization on Thermal Conductivity and Specific Heat of Two Corning Glass-Ceramics

A magnesium aluminosilicate glass-ceramic (Corning Code 9606) has been heat-treated at 900°, 1010°, 1200°, and 1260°C for up to 90 min., and the effect on the thermal conductivity between 30 and 300 K has been studied. It has been shown that the large increase of the thermal conductivity which results from the ceramming occurs predominantly when crystalline cordierite forms. At 1260°C, heat treatment for only 20 min leads to a thermal conductivity identical to that measured for commercial 9606, which has been cerammed for 8 h at the same temperature. This observation provides further evidence for the usefulness of commercial 9606 as a thermal conductivity standard. Measurements of the specific heats of Code 9606 before and after ceramming have been reviewed and have been found to be close to that of crystalline SiO₂ above ∼ 30 K, regardless of the state of ceramming. A review has also been made of thermal conductivity and specific heat of several ZrTiO₄ nucleated lithium aluminosilicate glass-ceramics at various states of ceramming. The thermal conductivity of these glass-ceramics seems to be sufficiently independent of chemical composition as well as of the degree of crystallization to warrant a recommended curve for this class of glass-ceramics.     

Crystallization of Lead Niobate Glass by Mechanical Activation

Mechanical activation-triggered crystallization in PbNb₂O₆-based glass was dependent on the initial presence of nuclei. The crystallization cannot be initiated by mechanical activation in a highly amorphous glass composition quenched from 1350°C where PbNb₂O₆ nuclei did not exist. The steady growth of nanocrystallites of PbNb₂O₆ was observed with an increasing degree of mechanical activation in the glass quenched from 1300°C, where a density of PbNb₂O₆ nuclei existed before mechanical activation. The inability to nucleate in the highly amorphous oxide glass by mechanical activation is consistent with the much higher structural stability as compared with that of metallic glasses, such as Fe-Si-B. The mechanical activation-grown PbNb₂O₆ nanocrystals were 10–15 nm in size as observed using HRTEM and their crystallinities were further improved by thermal aging at an elevated temperature in the range of 550° to 650°C.