氧氮化物玻璃

氧氮化物玻璃是一种特种玻璃。与氧化物玻璃相比，其性能和结构上都存在较大差异。本文分析了几种与氮化硅有关的氧氮化物玻璃的形成范围及其网络结构特征。同时，对氧氮化物玻璃的密度、显微硬度、杨氏模量、断裂韧性、粘度及转变温度和析晶性与含N量之间的关系进行了探讨。     

碱金属氧化物引入量对MgO-Al2O3-SiO2微晶玻璃结构及其化学增强效果的影响

采用K2 O、Li2 O取代玻璃中的Na2 O,通过"熔融-整体析晶"法制备了MgO-Al2 O3-SiO2系统微晶玻璃,并于450℃的KNO3熔盐中强化6 h.运用DSC、XRD、表面应力测试仪、显微硬度仪等测试方法和仪器,研究碱金属氧化物引入量对微晶玻璃微观结构和离子交换工艺的影响.研究结果表明:750℃晶化处理之后,含4wt％K2 O的微晶玻璃样品与不含K2 O样品相比,离子交换后表面应力深度由19.78μm提高至42.21μm,但表面应力却由786.34 MPa降低至580.57 MPa,玻璃硬度由762.10 Hv降至694.12 Hv;含有1wt％K2 O及1wt％Li2 O的微晶玻璃样品,离子交换后应力深度为19.56μm,应力大小为779.71 MPa,与不含K2 O样品相近,但硬度较低,为745.80 Hv.     

CaO、ZnO对MgO—Al2O3-SiO2玻璃性能及析晶的影响

在含碱金属氧化物的MgO-Al2O3-SiO2系玻璃中进一步引入CaO、ZnO,测定了玻璃的密度、硬度,采用DTA、XRD、SEM分析了玻璃的析晶情况。结果表明：CaO、ZnO使玻璃密度呈增大趋势,但二者加入后,玻璃硬度减小,其中同时含CaO、Zn0的玻璃较只含CaO玻璃硬度大。差热分析显示,CaO、ZnO可减小玻璃的粘度,降低Tg点温度,促进玻璃的析晶;含CaO、ZnO的玻璃热处理后主要析出硅酸锂铝、钠钙长石,镁钛氧化物晶相;随ZnO的引入,热处理玻璃中还出现锌尖晶石晶相;此外,含CaO、Zn0玻璃随热处理时间延长,还有少量霞石析出。析出晶体均以棒状晶体为主,颗粒状晶体弥散分布在棒状晶体之间。     

铅镧氟锆酸盐系统玻璃的形成与性质

本文研究了一系列加入不同量AlF_3后PbF_2-LaF_3-ZrF_4系统玻璃形成区。当AlF_3引入量小于5mol％时,PbF_2-LaF_3-ZrF_4系统有较大的形成区,形成稳定的玻璃。PbF_2与BaF_2相比,可以在LaF_3-ZrF_4系统中引入量较大。应用电镜研究铅镧氟锆酸盐系统玻璃的结果表明,玻璃中存在分相现象,而且在一些氟锆酸盐系统玻璃的差热分析曲线上可以明显地观察到二个转变温度T_8。液-液分相导致玻璃的整体析晶。本研究工作中,系统地测定了玻璃的折射率、红外透射性质、显微硬度、密度、导电率、化学稳定性等性质。对玻璃热处理后所产生的析晶晶相用X射线衍射相进行了系统的研究。在不同热处理条件下,可以形成PbF_2·ZrF_4与LaF_3·2ZrF_4等晶相。在红外与Raman光谱研究的基础上,提出了一个铅镧氟锆酸盐玻璃结构的示意图。     

晶化制度对矿渣微晶玻璃析晶行为的影响作用研究

以铁尾矿、硼泥和粉煤灰为原料,采用熔融法工艺制备微晶玻璃,借助XRD、SEM和显微硬度等测试方法,研究了晶化制度对微晶玻璃结构和性能的影响。试验结果表明:随着晶化温度的升高和晶化时间的延长,微晶玻璃中主晶相均为辉石相,且随着晶化温度的升高和晶化时间的延长,晶体尺寸逐渐增大,而微晶玻璃的表观体积密度和显微硬度呈升高后降低的趋势。     

Bi2O3–B2O3二元系统玻璃的网络结构形成与光学性能研究

采用高温熔融–退火法制备了一系列Bi2O3–B2O3二元系统玻璃,系统研究了不同Bi/B摩尔比下B2O3和Bi2O3在玻璃网络结构中的竞争机制,重点探讨了组成对铋酸盐玻璃光学和结构性能的影响。通过吸收光谱和Raman光谱分析了Bi2O3–B2O3二元系统玻璃的网络形成机理,测试了玻璃的密度和线性折射率。结果表明:Bi3+和B3+均为玻璃网络形成体,Raman光谱以600cm–1为中心,其附近的Raman信号强度发生的有规律性变化:低能量区的Raman峰与玻璃中引入的铋离子有关,而高能区的Raman峰与玻璃中的硼氧结构体有关。     

纳米SiO2掺入的硼铝酸盐微晶玻璃的结构与性能研究

硼铝酸盐玻璃具有超强的抗裂纹形成能力，但其硬度偏低限制了其在盖板玻璃领域的进一步应用。通过微晶化可有效提升其硬度，采用二次熔融浇铸法获得不同SiO₂含量的Li₂O-B₂O₃-Al₂O₃(LBA)基础玻璃，研究了不同SiO₂含量对基础玻璃以及微晶玻璃的显微结构及可见光透过率、硬度和耐划伤性能的影响规律。研究表明，SiO₂掺入的LBA基础玻璃经575℃保温2h晶化处理后，析出颗粒状的Li(Al₇B₄O₁₇)晶相，SiO₂的掺入能够抑制晶相析出，有利于提高玻璃的硬度和耐划伤性能。当SiO₂掺入量为0.5%时，微晶玻璃显微硬度高达6.85GPa的同时仍然保持较高的透过率(88.18%)，这分别得益于其内部析出的大量致密纳米级晶粒对裂纹的形成与扩展的有效阻止以及对可见光的散射与吸收较弱，使其在手机盖板玻璃方面具有较...     

含镝玻璃的制备及性能研究

以Dy2O3、Li2CO3和H3BO3为原料,制得满足医学使用要求的DyLB系统玻璃微球.通过测定该系统的密度、显微硬度、结构以及生物特性,结果显示:DyLB玻璃的密度随Dy2O3替代B2O3而逐渐增大;当Li2O质量分数为10%,显微硬度随Dy2O3含量的增加先升高后降低;DyLB玻璃微球具有良好的生物相容性.     

若干硫卤化物系统玻璃的形成及其性能

系统地研究了若干三元硫卤化物系统玻璃的形成情况,发现若干玻璃形成能力良好的新玻璃系统,通过地这些玻璃的特征温度,密度,显微硬度,红外透过性能,导电性和化学稳定性等物理化学性质的研究表明,一些玻璃系统具有良好的应用前景。     

SiO2—PbO—ZnO系统微晶玻璃的制备和性能

利用传统熔体冷却方法而制得ＳｉＯ２—ＰｂＯ—ＺｎＯ系统玻璃并探索了该系统微晶玻璃的制备工艺。研究表明：以ＣｅＯ２或ＣｅＯ２／ＴｉＯ２作为成核剂，可通过一步法热处理而获得该系统微晶玻璃，微晶玻璃中含Ｌｉ２ＺｎＳｉＯ４和Ｌｉ８Ｚｎ１０Ｓｉ７Ｏ２８两种晶体；该系统玻璃微晶化后，密度、显微硬度、抗压强度都有较大幅度的增加并有较高的热膨胀系统，但微晶化后材料的抗弯强度比相应玻璃低。     

粉煤灰制备微晶玻璃组织与性能的研究

本文利用粉煤灰与石英砂为主要原料制备不同成分的微晶玻璃,并进行核化、晶化。利用扫描电镜对核化、晶化的微晶玻璃进行组织观察,利用硬度计对其硬度测定并对其密度进行测量。研究表明,通过核化、晶化后的微晶玻璃的硬度、密度均升高。当粉煤灰含量较高时,析出网状的晶体组织,并且其在晶化后的硬度增加较少。但当有晶核剂二氧化钛大于5%时,无网状组织析出,且其在晶化后硬度明显提高。     

KOH对离子交换增强硼硅酸盐玻璃性能的影响

采用低温型离子交换法对硼硅酸盐玻璃进行增强。以掺有添加剂KOH的KNO3混合熔盐作为离子交换源,研究KOH掺入量对硼硅酸盐玻璃抗折强度、显微硬度和透过率的影响。采用扫描电子显微镜(SEM)观察离子交换后试样的表面形貌和结构。研究结果表明:KNO3熔盐中的WKOH/WKNO3为0.5时,硼硅酸盐玻璃的抗折强度和显微硬度都取得了最大值。     

Slow sintering in garnet-containing Y and Gd zirconate–aluminate mixtures for thermal barrier coatings

Mixtures of rare-earth zirconates and aluminates containing Y or Y + Gd that form a two-phase garnet–fluorite mixture exhibit much slower sintering than pure fluorite at 1400°C. An equivalent Y-free, Gd-containing composition that forms a perovskite aluminate instead of garnet showed faster densification after the metastable garnet decomposes. At 1500°C, the Y-free sample also showed the fastest initial sintering rate, whereas there was more divergence in the sintering rate for the samples containing Y + Gd. The zirconate–aluminate with equimolar Y + Gd shows the slowest densification at 1500°C and retains ∼25% porosity after 250 h. The results highlight possibilities for designing compliant thermal barrier coatings that can retain significant porosity at 1400°C or higher.     

含钆漆酚基聚合物的合成及表征

由漆酚和漆酚苯胺醛缩聚物分别与三氯化钆反应合成含钆漆酚基聚合物〔漆酚钆聚合物 (PUG)和漆酚苯胺钆聚合物 (PUAG)〕。用IR、XPS、DMTA和DSC -TG对产物进行表征。结果表明 ,与Gd(Ⅲ )发生配位反应的是漆酚基聚合物中酚羟基氧原子 ;漆酚基聚合物与Gd(Ⅲ )反应后 ,其侧链进一步交联聚合形成具有较高模量和良好热稳定性的含钆漆酚基聚合物 ,PUAG的耐热性比PUG的好。     

Influence of Point Defects in a Surface Layer on the Strength Characteristics of Glasses

The influence of the nature and the concentration of defects in a surface layer on the radiation resistance and the microhardness of silicate glasses is studied by photoemission spectroscopy. The investigation is performed with two types of silicate glasses: the K8 optical glass irradiated with fast electrons and an industrial sheet glass with a thermally polished surface. It is established that the radiation resistance and microhardness of glasses are determined by the content of structural defects of a particular nature. The radiation resistance of the surface of K8 optical glass decreases with an increase in the concentration of radiation E ^– ₄-centers, which are representative of the density of band-tail localized electron states recharged by irradiation. The microhardness of the studied glasses with different treatment of their surface depends linearly on the number of defect centers at the nonbridging and radiation-damaged bridging bonds of the silicon–oxygen network.     

Hyperbranched‐modified epoxy thermosets: Enhancement of thermomechanical and shape‐memory performances

In this study a complete characterization of the thermomechanical and shape‐memory properties of epoxy shape‐memory polymers modified with hyperbranched polymer and aliphatic diamine was performed. Focusing on the mechanical properties that are highly desirable for shape‐memory polymers, tensile behavior until break was analyzed at different temperatures and microhardness and impact strength were determined at room temperature. As regards shape memory performance, the materials were fully characterized at different programming temperatures to study how this influenced the recovery ratio, fixity ratio, shape‐recovery velocity, and switching temperature. Tensile testing revealed a peak in deformability and in the stored energy density at the onset of the glass transition temperature, demonstrating that this is the best programming temperature for obtaining the best shape‐memory performances. The Young's moduli revealed more rigid structures in formulations with higher hyperbranched polymer content, while microhardness showed higher values with increasing hyperbranched polymer content due to the increased crosslinking density. Impact strength was greatly improved as the aliphatic diamine content increases due to the energy dissipation capability of its flexible structure. As regards the shape‐memory properties, increasing the programming temperature has a minor effect on formulations with a lower hyperbranched polymer content and worsens these properties when the hyperbranched polymer content is increased. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44623.     

Cordierite glass‐ceramic used for transparent tile glazes

This study aimed at producing a high transparent and colorless cordierite glass‐ceramic that is used for a tile glaze with a single firing. Crystallization path of glaze, microstructure development, abrasion performance, microhardness, and the transparency of cordierite glass‐ceramic were tested. The results suggested that the high transparency was significantly affected by the number of internal air holes and the crystal scattering loss. The maximum crystalline content of cordierite was nearly 50 wt% at 1200°C. Due to the high crystallization content of cordierite and the bulk crystallization mechanism, the cordierite crystalline glaze has a higher microhardness and abrasion resistance than noncrystalline glaze.     

Glass Properties in the Yttria-Alumina-Silica System

The glass formation region in the yttria-alumina-silica system was investigated. Properties of glasses containing 25 to 55 wt% yttria were measured and the effect of the composition was determined. The density, refractive index, thermal-expansion coefficient, and microhardness increased with increasing yttria content. The dissolution rate in IN HCl increased with increasing yttria content and temperature. These glasses were also found to have high electrical resistivity.     

Comparison of the Properties of Oxycarbide and Oxynitride Glasses

Oxycarbide glasses in the Mg-Al-Si-O-C system and oxynitride glasses in the Mg-Al-Si-O-N system were synthesized by conventional melting techniques, chemically analyzed, and evaluated for selected mechanical properties as a function of carbon or nitrogen content. Both glass systems exhibited increases in density, Young's elastic modulus, microhardness, and fracture toughness with increasing anionic substitutions. Carbon substitutions were found to be more effective than nitrogen additions for improving glass properties.     

Glass‐transition temperature determination by microhardness in norbornene‐ethylene copolymers

Vickers microhardness as a function of temperature was determined in a series of norbornene‐ethylene copolymers synthesized with a metallocene catalyst. The norbornene content in the samples ranges from 31 to 62 mol %, and all of them were found to be amorphous. The possibility of studying the glass‐transition temperature by plotting the microhardness‐temperature dependencies is discussed in addition to the limits and the reliability of the suggested method. Moreover, a linear dependency between microhardness at different temperatures and glass‐transition temperature was established. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3666–3671, 2003