纤维玻璃耐碱性的研究

本文采用碱液浸泡法对无碱、中碱和耐碱玻璃耐碱性进行测试和研究,通过玻璃在不同碱性介质、不同温度和时间作用后受碱侵蚀的失重和浸出的SiO2含量表征纤维玻璃在的耐碱性.测试结果显示三种纤维玻璃的耐碱性排列为:耐碱玻璃》中碱玻璃》无碱玻璃.     

Na2O—Al2O3—SiO2系统霞石微晶玻璃化学稳定性的研究

Ｎａ２Ｏ－Ａｌ２Ｏ３－ＳｉＯ２系统霞石微晶玻璃的化学稳定性是该材料的重要性能之一。采用酸碱溶液侵蚀的方法,在比较霞石微晶玻璃试样与基玻璃试样侵蚀失重的基础上,分析了霞石微晶玻璃在酸,碱溶液中的侵蚀机理,同时,研究了侵蚀时间和酸,碱溶液浓度对霞石微晶玻璃试样侵蚀失重的影响。     

MgO-ZnO-Al_2O_3-ZrO_2-SiO_2玻璃碱侵蚀过程的X射线能谱和扫描电镜研究

用扫描电镜(SEM)和X射线能谱(EDAX)研究了MgO-ZnO-Al_2O_3-ZrO_2-SiO_2玻璃在5%NaOH溶液中的侵蚀过程。分析了表面侵蚀层的成分,观察了不同阶段的侵蚀层形貌,并测量了侵蚀层厚度的变化。结果表明,玻璃的碱侵蚀以各组分(SiO_2、ZnO、MgO)选择性地溶解交替的方式进行,ZrO_2在表面富集的现象只在某一定阶段发生。在7h以内的碱侵蚀过程中并没有观察到含锆的抗碱层形成,但表面层结构变得较为致密。侵蚀层厚度的变化与成分变化相对应。讨论了玻璃表面侵蚀凹坑形成的原因,认为它是分布不均匀的组分结构选择性溶解的结果而不是表面机械擦伤或微裂纹所致。     

SiO2-TiO2-Al2O3-R2O系统逆性玻璃中TiO2耐碱二重性的探讨

通过测定SiO2-TiO2-Al2O3-R2O系统逆性玻璃的耐碱性及由玻璃转入碱侵蚀液中的SiO2及TiO2的量,分析了TiO2在玻璃耐碱性上的二重性,得出氧化物自身的耐碱性与氧化物对玻璃耐碱性的影响是2个不同的概念.     

提高Na_2O-TiO_2-SiO_2系玻璃化学稳定性的研究

在探讨Na_2O-TiO_2-SiO_2 系玻璃组成对其性质、结构影响的基础上,研究了提高该系玻璃的化学稳定性问题,通过X射线微电子探针测定水侵蚀该系玻璃的表面成分变化;离子选择电极法和分光光度法测定水侵蚀物中微量K~+、Na~+、Ti~(4+)离子的量,阐明了水侵蚀该系玻璃的机理,认为主要是由R~+离子扩散及与H~+离子交换作用控制其侵蚀过程。研究和讨论了混合碱效应对该系玻璃化学稳定性的影响及应用,以及二氧化钛在该系玻璃中及玻璃表面层的结构状态。发现在较多量碱金属氧化物情况下(含21％),当R_2O/TiO_2?1、K_2O/Na_2O?2.5、TiO_2/SiO_2?0.4时,可以得到具有实用价值的高化学稳定性的15K_2O·6Na_2O·26TiO_2·53SiO_2稳定玻璃。     

微硅粉中SiO2在稀碱液中的溶解行为及动力学

研究了微硅粉中SiO2在稀碱溶液中的溶解行为及溶解动力学,考察了反应时间、NaOH初始浓度及反应温度对SiO2浸出率的影响,并分析了原料和浸出渣的物相. 结果表明,SiO2的浸出率随碱初始浓度和反应温度增加而增加. 微硅粉中无定型SiO2在NaOH稀碱液中的溶解表观活化能为18 kJ/mol,说明该溶解反应由扩散控制.     

N31型磷酸盐激光钕玻璃的耐水性

通过测试N31型掺钕磷酸盐激光玻璃在水浴中质量损失随时间的变化情况,讨论了该玻璃在水溶液介质中的化学稳定性和微观侵蚀机理.结果表明:N31型玻璃化学稳定性良好,在水溶液介质中各离子都有自身的溶解规律;经过一段线性溶解过程后,各离子的溶解速率明显下降,这是由于在钕玻璃局部表面生成了保护膜.     

含稀土ZnO-B2O3-SiO2玻璃的化学稳定性

为了探索稀土氧化物掺杂对硼硅酸盐玻璃化学稳定性的影响,利用熔融冷却法制备了掺杂Nd2O3、Gd2O3和Y2O3的ZnO-B2O3-SiO2系玻璃.在一定的条件下,对玻璃在去离子水、酸、碱液态侵蚀介质中的腐蚀行为进行了研究.利用扫描电镜和能谱分析对腐蚀后的玻璃样品表面形貌和成分变化进行了表征,对酸性侵蚀介质中出现的白色沉淀进行了X射线物性分析,同时利用电感耦合等离子光谱仪测定了去离子水中浸出离子的浓度.结果表明:该系统玻璃的化学稳定性顺序为:耐酸性＜耐碱性＜耐水性.稀土氧化物的添加降低了玻璃侵蚀过程中的质量损失,减轻了玻璃的腐蚀程度和抑制了各组分的浸出量.Y2O3、Gd2O3和Nd2O3的添加使得该玻璃在去离子水中钠离子的浸出量从148.703 μg/cm2分别降低到43.751,63.984和138.828 μg/cm2.Nd2O3、Gd2O3和Y2O3掺杂对硼硅酸盐玻璃化学稳定性的改善作用顺序为Y2O3＞ Gd2O3＞ Nd2O3.     

环保高效光学玻璃清洗剂的研制及应用研究

本文成功研制出一种环保高效的光学玻璃清洗剂。该清洗剂配方组成为油酸皂3 wt%，异构醇聚氧乙烯醚1 wt%，三乙醇胺5 wt%，二乙二醇单丁醚2 wt%，烷基糖苷5 wt%，葡萄糖酸钠3 wt%，五水偏硅酸钠2 wt%，氢氧化钠5 wt%,EDTA-4Na 1 wt%，去离子水73 wt%。研究了表面活性剂种类、温度、浓度、时间对玻璃清洗剂清洗效率的影响。在5 wt%稀释浓度，40-55℃条件下清洗2 min可充分发挥玻璃清洗剂的清洗效果，清洗效率高达95%以上，且无白点、毛边、烧蚀现象。解决了行业中在较低碱浓度下清洗效果不足、较高碱浓度下易造成玻璃碱蚀的问题。由此可见，所得清洗剂在光学玻璃清洗领域具有广阔的应用前景。     

ZrO_2在硅酸盐玻璃中抗碱性能的研究

为了研究ZrO_2在硅酸盐玻功中的抗碱性能,须测定SiO_2玻璃,SiO_2—ZrO_2—Na_2O系玻璃及SiO_2—TiO_2—Na_2O系玻璃碱侵蚀时的表观活化能,并对侵蚀后的玻功表面进行分析。测定在碱溶液中加入ZrOCl_2,Ti(SO_4)_2,Na_2SiO_3时玻璃的侵蚀量,从而研究关于玻璃组成和侵蚀机理的关系。SiO_2玻璃,SiO_2—ZrO_25—Na_2O系玻璃及SiO_2—TiO_2—Na_2O系玻璃在碱溶     

Reaction of Dehydrated Surface of Partially Leached Glass with Water

Glasses containing sodium and potassium were leached with water and the alkali was extracted by a linear relation with square root of time. The leached surfaces were then dried by different techniques, heat-treated at various temperatures, and again attacked by water. For glasses containing Na₂O, the heat-treated preleached grains showed neither extraction behavior having a linear relation with time nor extraction by a square root-time relation. For glasses containing K₂O, the heat-treated preleached glass grains showed a linear relation of extraction. The results were explained by a structural transformation for the sodium glasses, in which an S-shaped sodium ion distribution at the surface layer was greatly affected by the heat treatment. For the potassium glasses no such transformation could occur since the alkali ion distribution was exponential and unaffected by temperature.     

La2 O3对SiO2-Al2 O3-CaO-MgO系统玻璃结构与性能的影响

采用高温熔融法制备了SiO2-Al2 O3-CaO-MgO系统玻璃,研究添加La2 O3对SiO2-Al2 O3-CaO-MgO系统玻璃密度、耐碱性、弹性模量以及析晶上限温度的影响,并借助红外光谱对玻璃的结构进行研究。结果表明：随着La2 O3含量从0升高至5wt%,玻璃的网络结构发生改变;玻璃的密度和摩尔体积均增大;玻璃的耐碱性能降低;弹性模量从90.5 GPa增加至93.6 GPa后降低,最大值对应的La2 O3含量为3wt%;析晶上限温度从1224℃降低至1209℃后增加至1212℃,最后趋于不变,在La2 O3添加含量为2wt%时达到最低温度。     

新型SiO2-TiO2-BaO-CaO耐碱涂层

采用Sol-gel方法制备出新型SiO2-TiO2-BaO-CaO耐碱涂层.合成了适合于浸涂工艺的稳定溶胶涂液.红外光谱表明:醋酸与钛离子形成稳定的配位体,从而延长了凝胶时间;500℃处理后,凝胶中已形成氧化物网络.通过测定侵蚀后涂膜玻璃的失重量和原子吸收光谱,分析组成和热处理温度对涂层耐碱性的影响.XRD图谱和SEM照片表明:涂膜玻片经NaOH侵蚀后,表面形成富钛保护层,提高耐碱性,而侵蚀后生成的复杂晶体使侵蚀加剧.     

Chemical and electrical properties of the surface layers of some glass electrodes

Some sodium— and lithium—silicate pH responsive glasses exhibited a stepwise alkali ion profile with distance inwards towards the glass as a result of attack by aqueous solutions, ie, the average alkali ion concentration of the gel layer was low but increased rapidly within a transition region between the gel layer and the glass bulk. The electrical resistivity of the gel layer was a factor at least five times lower than that of the original glass. An extremely high electrical resistance in the transition region was found to be proportional to the chemical durability of the glass independent of hydration time. The smaller size of the lithium ion which favours stronger binding, compared with the sodium ion, as well as the action of the calcium ion in the sodium silicate network to block the sodium ion/hydrogen ion exchange were among the factors that increased the chemical durability by orders of magnitude. Equilibrium conditions were not reached for the deeper parts of the gel layers. The chemical durability of the glass increased in the same order as found for the ideal function of the glass electrode. The size of the electrical resistance of the transition region was thus useful for deducing glass compositions suitable for electrode purposes.     

碱法提高铝硅矿物的铝硅比

采用NaOH溶液时铝硅矿物进行预脱硅处理,测出溶渣中SiO2和Al1O3的含量,计算得出渣中的铝硅比.考察液固比、溶出温度、溶出时间、碱浓度等因素对铝硅矿物溶出后渣中铝硅比的影响.实验表明,在液固比为40∶1、温度95℃、溶出时间3 h、40%碱浓度条件下,矿物的脱硅率可达55%以上.预脱硅后渣中铝硅比由0.89提高到...     

CHEMICAL DURABILITY OF PORCELAIN ENAMELS *

The resistance of representative porcelain enamel surfaces to the chemical attack of different concentrations of various solutions was investigated in considerable detail. Cylindrical cup-shaped samples were coated with (1) a ground coat, (2) a white fluoride cover enamel, (3) a white antimony cover enamel, (4) a white zirconium cover enamel, (5) an acid-resistant white cover enamel, (6) a sign blue cover enamel, (7) a blue zirconium enamel, and (8) a chemical acidproof blue cover enamel. The loss in weight of these enamel surfaces, after exposure to chemical attack, was determined at definite time intervals. The solutions studied consisted of different concentrations of the inorganic acids, alkalis, several organic acids, as well as selected salt solutions at both room and boiling temperatures. Numerous curves are presented showing the comparative chemical durability of the various porcelain enamel surfaces in which the cumulative loss in weight is plotted against time. Several photomicrographs show the nature and type of chemical attack on the different surfaces. The porcelain enamel surfaces showed considerable variation in their resistance to the chemical attack of the various solutions. All of the porcelain enamels were, in general, resistant to attack at room temperature by the alkali and salt solutions. The acid-resistant and acidproof enamels were resistant to the action of both inorganic and organic acids at room and at boiling temperatures; a wide variance, however, was shown in the comparative acid resistance of the non-acid-resisting enamel to the attack of either organic acids or inorganic acids at room temperature. AU porcelain enamels showed equally low resistance to boiling alkali solutions, but some of the enamel surfaces were attacked markedly by the boiling salt solutions.     

Electron Micrographs of Some Borosilicate Glasses and Their Internal Structure

Many electron micrographs were obtained for borosilicate glass which had been subjected to chemical attack after heat-treatment at various temperatures and durations in order to study changes in internal structure, the so-called "phase separation." Both replica and direct-transmission methods were applied to Vycor-type glass. The two kinds of picture showed good agreement with each other. The conclusions obtained are as follows: (1) So-called quenched-state glass contains a glassy microphase of alkali borate, with dimensions less than 100 a.u., which corresponds to the so-called low-melting component; (2) the longer the heat-treatment time under constant temperature the larger the size of this glassy microphase becomes; (3) another kind of glassy microphase (SiO₂-rich) which corresponds to the so-called high-melting component is also enlarged with increasing heat-treatment time; (4) the size of both glassy microphases shows different values with different heat-treatment temperatures. Based on the experimental results described, a discussion of the relation between the internal structure and some physical properties of the glass is presented.     

Characterization of Insoluble Layers Formed by NaOH Attack on the Surface of a ZrO2-Containing Silicate Glass

The durability of an alkali-resistant glass containing ZrO₂ in NaOH solution was studied by scanning electron microscopy. Insoluble Zrrich reaction-product layers ∼1 to 3 μm thick were observed on the surface of glass which had been soaked for 25 d in 2N NaOH at 95°C. In some cases the layer seems to be an adherent film, but in others it adheres loosely to the glass surface and does not seem to effectively block alkali attack .     

Internal Friction of Ion-Exchanged Li2O.Al2O3.2SiO2 Glass

Fibers of Li₂O.Al₂O₃.2SiO₂ glass were ion-exchanged for 1 to 300 min in an NaNO₃ bath at 366°C. The internal friction and the Li and Na concentration profiles were measured. As Na progressively replaced Li, the alkali internal friction peak became smaller while a new peak (mixed-alkali peak) appeared and increased in magnitude. These changes in internal friction are similar to those that occur when a second alkali is added to glasses prepared by conventional melting. The magnitudes of both internal friction peaks in the ion-exchanged glass depended on the overall composition of the glass; that of the alkali peak depended on the composition of the unexchanged glass core, whereas that of the mixed-alkali peak depended on the composition of the exchanged layer on the glass surface. When the exchanged surface layer was dissolved, the original alkali peak was restored, and the mixed-alkali peak disappeared. Changing the alkali distribution did not affect the mixed-alkali peak much; however, it caused the alkali peak to shift to higher temperatures and become smaller. The height of the alkali peak can be used to determine the maximum depth of penetration of the second alkali.