锂铝硅微晶玻璃的合成工艺、性能及其影响因素

锂铝硅微晶玻璃（LAS Glass-ceramics）与其他微晶玻璃相比具有极低的热膨胀性能,在光学领域、航空航天领域和微电子领域有巨大的应用潜力,引起了众多研究者的关注。本文通过对近年来国内外锂铝硅微晶玻璃的研究现状进行分析,从锂铝硅微晶玻璃的合成工艺、微结构、性能以及存在的问题等方面进行了总结与讨论,旨在为锂铝硅微晶玻璃新材料的开发和性能改进提供新的思路。     

MgO含量对微晶玻璃结构及性能的影响

锂铝硅系微晶玻璃是一种具有优异的光学、力学性能的微晶玻璃材料。本文制备了以透锂长石和二硅酸锂为主晶相的锂铝硅系透明微晶玻璃,并通过DSC、XRD与SEM研究了MgO含量对该微晶玻璃析晶行为及结构的影响,利用维氏硬度、抗弯强度等测试方法研究了MgO含量对该微晶玻璃力学性能的影响。结果表明,当MgO含量(质量分数)从0%增加至3%,基础玻璃的析晶温度从771 ℃降低至729 ℃,析晶能力增强,微晶玻璃的结晶度从62%增加至72%,晶粒尺寸从29 nm增大至33 nm。随着MgO含量的增加,微晶玻璃中会析出β-石英固溶体,抗弯强度增大。     

晶化温度对锂铝硅微晶玻璃热膨胀系数和热稳定性的影响

通过制备锂铝硅基础微晶玻璃,对其进行差热分析,在不同温度下进行晶化处理,对微晶玻璃的热膨胀系数和热稳定性进行测试分析,并讨论了晶化温度对这两种性能的影响。     

人工神经网络在锂铝硅超低膨胀透明微晶玻璃热处理研究中的应用

人工神经网络在锂铝硅超低膨胀透明微晶玻璃热处理研究中的应用陈建华，孙方明（盐城工业专科学校２２４００３）（华东理工大学２００２３７）ＡｒｔｉｆｉｃｉａｌＮｅｕｒａｌＮｅｔｗｏｒｋｓＡｐｐｌｉｅｄｔｏＳｔｕｄｙｏｆＨｅａｔＴｒｅａｔｍｅｎｔｏｆＬｉｔｈ...     

零膨胀锂铝硅透明微晶玻璃的研究与应用现状

外界温度的剧变,易在材料中产生热应力,导致材料失效.零膨胀锂铝硅透明微晶玻璃卓越的热学性能,优良的光学和机械性能使之成为不可或缺的综合材料.主要介绍零膨胀LAS系透明微晶玻璃的主要形态和结构特征,热学、光学性能以及应用现状,并提出了研究中存在的问题及今后发展的方向.     

锂铝硅玻璃的研究进展

与传统的钠钙硅玻璃和高铝玻璃相比,锂铝硅玻璃具有网络结构致密、弹性模量较高和适宜两步法化学钢化等特点,被视为第三代高强玻璃基板,可用作电子信息产品盖板、航空透明器件以及舰船、特种车辆的观察窗口等。目前,锂铝硅玻璃的研究主要涉及:(1)探究锂铝硅玻璃的“组成-结构-性能”本构关系,为设计优化高性能锂铝硅玻璃提供理论指导和性能预测;(2)改进现有溢流和浮法成型方法和装备,满足大尺寸、多厚度和高尺寸精度锂铝硅玻璃成型需要;(3)研究锂铝硅玻璃的两步法化学增强方法,解决表面压应力和应力层深度同步提升难题,显著提高玻璃强度、硬度和抗跌落性能。本文基于上述三个方面综述了锂铝硅玻璃的国内外研究进展。     

超低膨胀锂铝硅透明微晶玻璃的研究与应用现状

环境温度的变化,会引起材料的膨胀与收缩,在材料中产生热应力,会影响材料使用。零膨胀锂铝硅透明微晶玻璃卓越的热学性能,优良的光学和机械性能使之成为不可或缺的综合材料。本文主要介绍了零膨胀LAS系透明微晶玻璃的主要形态和结构特征,热学、光学性能以及应用现状,并提出了研究中存在的问题及今后发展的方向。     

锂铝硅玻璃

基于锂铝硅玻璃组成-性能-结构之间的构效关系，分析对比适合锂铝硅玻璃的成形方法。通过优化化学强化工艺，实现锂铝硅玻璃在航空航天、电子产品、消费品、光学领域的产业化应用，以推动我国高性能玻璃的安全与健康发展。     

锂铝硅透明微晶玻璃的发朦现象研究

锂铝硅透明微晶玻璃的发朦现象研究陈建华，孙方明（盐城工业专科学校２２４００３）（华东理工大学２００２３７）ＳｔｕｄｙｏｎＨａｚｅｄＳａｍｐｌｅｓｏｆＴｒａｎｓｐａｒｅｎｔＬｉｔｈｉｕｍＡｌｕｍｉｎｏｓｉｌｉｃａｔｅＧｌａｓｓ－Ｃｅｒａｍｉｃｓ￥Ｃｈｅ...     

锂铝硅透明微晶玻璃着色研究

引入Cr2O3、CoO、NiO、MnO2等过渡金属氧化物对低膨胀锂铝硅透明微晶玻璃进行着色研究,结果表明,微晶玻璃与其母体玻璃相比,颜色有明显的不同,主波长向长波方向移动。研究还发现,在从核化阶段到晶化阶段的过程中颜色变化最为明显,而在核化阶段和晶化阶段颜色没有发生明显的变化。同时运用配位场理论和光散射原理来解释这种颜色变化的原因。     

Mechanical Properties of a Lithium Disilicate Strengthened Lithium Aluminosilicate Glass‐Ceramic

A glass composition in the Li₂O–Al₂O₃–SiO₂ (LAS)‐ternary phase diagram is presented, which enables the crystallization of Li₂Si₂O₅ as well as LiAlSi₂O₆ upon a well‐defined heat treatment. Li₂Si₂O₅ is the minor crystalline phase in the glass‐ceramic and generates through the bulk strengthening of the LAS glass‐ceramic. A flexural strength as higher as 400 MPa is measured in the proposed glass‐ceramic formulation, thus outperforming conventional LAS‐glass‐ceramics. A combination of the presence of those two crystalline phases of very different mechanical properties and coefficient of thermal expansion as well as the microstructure are believed to contribute largely to the enhancement of the measured properties.     

高强度Li2O-Al2O3-SiO2体系微晶玻璃研究进展

Li₂O-Al₂O₃-SiO₂(LAS)体系微晶玻璃因具有优异的力学性能和光学性能,近年来得到了广泛应用。本文针对LAS微晶玻璃的析出晶相、制备工艺和应用进行了介绍。鉴于当前对高硬耐划玻璃材料的迫切需求,重点阐述了LAS微晶玻璃强韧化技术和表面增强方法的研究进展,对今后研发高强度LAS微晶玻璃具有重要指导作用。     

短切SiC纤维含量对SiC_(sf)/LAS复合材料性能的影响

用热压烧结法制备了不同纤维含量的SiCsf/LAS玻璃陶瓷复合材料,研究了该复合材料的微观结构、力学性能和微波介电性能。结果表明:随着SiC纤维含量的增加,SiCsf/LAS材料的抗弯强度先增加后降低,最大值为104MPa。由于碳界面层的形成,SiCsf/LAS比LAS具有更高的介电常数。当SiC短切纤维的质量分数为1.5%时,SiCsf/LAS复合材料介电常数具有最大值,其实部ε′和虚部ε″均值分别为48和66,并具有明显的频散效应。     

Erbium-doped LAS glass ceramics prepared by spark plasma sintering (SPS)

Dense nanocrystalline glass ceramics of the Li₂O–Al₂O₃–SiO₂ (LAS) system were obtained by spark plasma sintering (SPS) of powders prepared by sol–gel method. The low thermal expansion LAS glass ceramic was chosen as host matrix for erbium ions. ZrO₂ was added both as a nucleating agent and as a possible good environment for the rare earth. The developed crystalline phases were analysed by X-ray diffraction (XRD) and the amorphous phase was quantified. Scanning and transmission electron microscopy (SEM, TEM) was used to investigate the microstructure. A different behaviour during the crystallisation process was observed between the sample prepared through the sintering of powders and the glass produced by the melting technique. A photoluminescence characterisation was also performed.     

Crystallisation and characterisation of dielectric glass ceramics in Li2O–Al2O3–SiO2 system

Abstract

Glass ceramics in the Li₂O–Al₂O₃–SiO₂ system have been synthesised to produce bulk materials grown in a glass phase via quenching followed by controlled crystallisation. The crystallisation and microstructure of Li₂O–Al₂O₃–SiO₂ (LAS) glass–ceramic with nucleating agents (B₂O₃ and/or P₂O₅) are investigated by differential thermal analysis, X-ray diffraction and scanning electron microscopy and the effects of B₂O₃ and P₂O₅ on the crystallisation of LAS glass are also analysed. The introduction of both B₂O₃ and P₂O₅ promotes the crystallisation of LAS glass by decreasing the crystallisation temperature and adjusting the crystallisation kinetic parameters, allows a direct formation of β spodumene phase and as a result, increases the crystallinity of the LAS glass ceramic. Microstructural observations show that the randomly oriented, nanometre sized crystalline is found with residual glass concentrated at crystallite boundaries. Furthermore, it is interesting that codoping of B₂O₃ and P₂O₅ creates not much effect on the crystallisation temperature. The dielectric properties of the glass–ceramics formed through controlled crystallisation have a strong dependence on the phases that are developed during heat treatment. The dielectric constant is continuously increased and the dielectric loss is decreased with addition of additives where mobile alkali metal ions (e.g. Li⁺) are incorporated in a crystal phase and minimise the residual glass phase.     

The complexity of the matrix micro structure in SiC-fiber-reinforced glass ceramic composites

In this paper a critical examination of the diagrams of different silicate systems is presented: LAS, MAS YAS, MLAS and YMAS (A: alumina; L: lithia; M: magnesia; S: silica; Y: yttria). These systems have been developed to fabricate ceramic matrix composites based on a glass ceramic matrix, because of their low thermal expansion coefficient and good mechanical properties up to 1000 °C. The observations and microanalyses, by transmission electron microscopy, of different batches of MLAS and YMAS confirm the complexity of the systems investigated.     

WO3对零膨胀锂铝硅封接玻璃流动性的影响与作用机理

密封连接石英玻璃被广泛应用于航空航天、半导体加工以及微机电系统真空连接等领域。改进的低膨胀Li₂O-Al₂O₃-SiO₂(LAS)系微晶玻璃可以用于封接石英玻璃,但存在流动性不佳的难题。本文通过掺入WO₃对LAS系微晶玻璃进行改性,利用线膨胀系数分析仪、差示扫描量热仪、X射线衍射仪、高温烧结影像仪、扫描电镜,研究了掺入WO₃后LAS玻璃封接石英玻璃的机理。结果表明:WO₃对LAS玻璃的析晶产生先增强后削弱的影响; WO₃掺量越大,热膨胀系数越大,当掺量达到5.0%(质量分数)时,热膨胀系数提升至5.69×10^-7 ℃^-1;流动性与润湿性随着掺量增加而提升,铺展面积随掺量增加而增大,润湿角随掺量增加而减小,有效改善了LAS玻璃本身流动性不足的问题;LAS玻璃与石英玻璃之间主要是通过化学元素迁移实现封接。     

低熔封接微晶玻璃无铅化的最新研究进展及其发展趋势

低熔封接微晶玻璃是一种先进的焊接材料，由于其具有低的熔化温度和封接温度，优良的机械强度和化学稳定性，而在很多领域中得到广泛的应用，实现了玻璃、陶瓷、金属、半导体间的相互封接。综述了无铅低熔封接微晶玻璃的研究现状，展望了无铅低熔封接微晶玻璃今后的研究发展方向。     

Densification and Phase Development of Spodumene–Cordierite Glass Powder Mixtures

The sintering and crystallization of spodumene-cordierite glass-ceramics that are made from mixtures of Li₂O-Al₂O₃-SiO₂ (LAS) and MgO-Al₂O₃-SiO₂(MAS) glass powders were investigated. Pure LAS and MAS powders have good sinterability. However, the densification of LAS was drastically reduced when small amounts of MAS were added. When larger amounts of MAS were added, the amount of densification further increased. The decrease in the Li₂O content in the LAS glass promoted the densification of the mixed glass samples. The above-mentioned results can be explained by examining the crystallization temperature, which is influenced by the interactions between the LAS and MAS glass particles. The lower the temperature of crystallization, the less sintering occurred. For the sintered samples, the phase that crystallized from the MAS glass was alpha-cordierite, and that which crystallized from the LAS glass was ß-spodumene or high-quartz solid solution, depending on the Li₂O content in the LAS glass.     

TiC-TiB2复合陶瓷制备及性能研究

TiC-TiB2复合陶瓷因具有高硬度、高断裂韧性及优异的耐磨性,目前已成为工程陶瓷的研究热点。但是TiC-TiB2复合陶瓷的难以制备与难于致密,又使其应用受到极大限制。本文介绍了国内外TiC-TiB2复合陶瓷合成与制备方法、显微组织与力学性能等,特别提到了军械工程学院先进材料研究所采用超重力下燃烧合成技术,制备出大尺寸、高致密性的TiC-TiB2共晶复合陶瓷,从而为以后的更广泛应用提供了支持。