SiO2-Al2O3-MgO系高强玻璃纤维耐酸性能研究

采用高温熔融法制备了SiO2-Al2O3-MgO系统的S级高强玻璃纤维,研究了不同玻璃组分对玻璃耐酸性能的影响,利用扫描电镜(SEM)、红外光谱(IR)和核磁共振(NMR)等手段分析了酸侵蚀前后纤维的表面形貌和微观结构,进而分析了S级高强玻璃纤维在酸腐蚀环境下的破坏机理.结果表明:S高强玻璃的结构主要由硅氧四面体[SiO4]和铝氧四面体[AlO4]等构成,随着酸蚀的进行,玻璃网络结构被破坏,Si-O-Si断裂形成Si-OH键并形成凝胶附着在纤维表面;而铝氧多面体中Al-O键断裂,Al3+逐渐从玻璃结构中被置换出来,导致玻璃网络中Al3+浓度大大降低;高强系列玻璃的耐酸性能与玻璃表面的化学组成以及玻璃内部的微观结构关系密切.致密的玻璃网络结构有利于抑制H+对玻璃结构破坏,抑制阳离子与H+的置换作用;此外引入离子场强高的Ti4+,由于"积聚"作用而使玻璃结构致密,提高玻璃纤维的耐酸性.     

B2O3对SiO2-Al2O3-MgO系统高强玻璃纤维性能的影响

高强玻璃纤维具有质轻、高强、耐高温及性价比高等优异特性,广泛应用于复合材料领域.本文通过对不同B2O3含量的高强玻纤试样进行拉伸、侵蚀、粘度、红外等性能的测试,研究了B2O3含量对高强玻璃纤维各种性能的影响.结果表明在高强玻璃纤维中引入一定含量B2O3,提高了玻璃纤维的拉伸强度,降低了高温粘度,一定程度上改善了高强玻璃纤维的工艺性能和提高了力学性能.     

Y_2O_3掺杂对SiO_2-Al_2O_3-MgO系玻璃结构与机械性能的影响

采用传统熔体冷却法制备Y_2O_3掺杂质量分数为0~1.8%的SiO_2-Al2O_3-MgO系玻璃,探讨了Y_2O_3含量对玻璃弯曲强度、压缩强度、压缩模量和结构稳定性的影响规律。结果表明:当Y_2O_3掺杂量小于1.2%时,玻璃的光学带隙随着Y_2O_3含量的增加而减小、玻璃结构更加稳定,其弯曲强度、压缩强度以及压缩模量均随着Y_2O_3含量的增加而上升;当Y_2O_3含量超过1.2%后,该玻璃体系的结构稳定性和机械性能均随着Y_2O_3含量的增加而出现下降;当Y_2O_3的含量为1.2%时,玻璃的光学带隙最小,为3.11 e V,机械性能达到最优,其弯曲强、压缩度强度和压缩模量分别107.48 MPa、221.24 MPa和117.87 GPa。适量Y_2O_3的掺杂,减少了玻璃网络结构中非桥氧数量,使孤立的岛状网络单元重新聚合,增强了Si—O—Si反对称伸缩振动,增加了玻璃结构的稳定性,从而显著提高了玻璃的机械性能;但过量的Y_2O_3迫使玻璃结构中的桥氧键断裂,生成非桥氧,显著降低了玻璃的结构稳定性和机械性能。     

Al/Si比对SiO2-Al2O3-MgO系玻璃结构和性能的影响

SiO2-Al2O3-MgO系玻璃因具备强度大、弹性模量高等优异性能而用作高模量玻璃纤维的制备.采用熔融冷却法制备了不同Al/Si比的SiO2-Al2O3-MgO系基础玻璃,并研究了玻璃的结构和性能.红外光谱分析表明,玻璃网络结构由铝氧四面体[AlO4]和硅氧四面体[SiO4]相互连接而成.随着Al/Si比的增加,[AlO4]含量保持不变,[AlO6]含量逐渐增加.DSC分析表明,本系统玻璃的玻璃转变点Tg、成核温度Tx均随Al/Si比的增大而提高,玻璃的析晶倾向变强烈.热膨胀分析表明玻璃的热膨胀系数随Al/Si比的增大呈现先增大后减小的趋势.物理及机械性能测试结果如下:随Al/Si比的增大,密度、弹性模量均随之不断增大;而弯曲强度和维氏硬度则是持续降低.     

矿物原料对SiO_2-Al_2O_3-MgO玻璃熔制的影响研究

目前SiO_2-Al_2O_3-MgO系统的S级高强玻璃纤维生产主要以石英砂、氧化铝、重质氧化镁等化工级原料分别引入玻璃组分中的各氧化物实现。这些化工原料纯度高,有助于提高产品成分和性能的稳定性,但这些原料在熔制过程中需要更高的熔制温度,具有能耗大、玻璃液的澄清及均化困难等缺点。为改善SiO_2-Al_2O_3-MgO系统S级高强玻璃的熔制工艺性能,开展了在玻璃原料中引入高岭土、滑石粉的熔制实验,研究矿物原料对高强玻璃熔制的影响规律。通过DSC分析了玻璃的特征温度点,利用XRD表征了熔制过程中配合料的物相变化情况,并在快速升温炉中进行了配合料的熔制实验观测,同时进行了新生态玻璃纤维的强度测试。研究表明:采用矿物原料能显著降低配合料的熔制温度,降低熔制能耗,改善特种玻璃熔制的工艺性能,形成玻璃的温度降低50℃以上;同时也发现矿物原料中的Fe~(2+)含量较大,增加了玻璃液的温度梯度,玻璃液表面温度低,不利于玻璃液的澄清,因此需要采取措施降低矿物原料中Fe~(2+)的含量,以改善玻璃液的澄清效果,避免玻璃纤维的性能受到影响。     

高强玻璃中某些氧化物对其析晶性能的影响

高强玻璃成份是属于SiO_2—Al_2O_3—MgO系统的,为了试制高强玻璃,设计了料方,配制和熔化了一系列SiO_2—Al_2O_3—MgO玻璃.然后化验分析其化学成份,测试其析晶上限温度,最后选取最理想的玻璃成份进行拉丝,要求拉制成的玻璃纤维强度高,玻璃的析晶上限温度较低,析晶速度较慢,有合适的成型粘度等等.一般其化学成份波动范围为:     

S2高强玻璃纤维在轻型飞机及水上运动器材上的应用

我院经过二十多年的系统研究,目前已建立起一条年产30吨的高强玻璃纤维中间试验线,并于1990年6月通过国家建材局部级鉴定.S_2高强玻璃纤维的玻璃成份,是以SiO_2-Al_2O_3-MgO系统为基础,并引入少量B_2O_3、CeO_2、LiO、Fe_3O_3改性氧化物     

CaO-Al2O3-P2O5-MgO富玻璃相水泥合成及水化活性的研究

研究了CaO-Al2O3-P2O5-MgO系统富玻璃相水泥相组成、结构基团及水化性能.研究表明,在CaO-Al2O3-P2O5三元系统中引入碱土金属氧化物MgO,可在1450℃合成主矿相为玻璃相的富玻璃相水泥,其水化产物相结构稳定,浆体具有早强、高强且长期强度持续增长的特点.     

添加Li2O对ZnO-BaO-B2O3-SiO2系统玻璃结构与性能的研究

采用熔融冷却法制备了添加Li_2O的ZnO-BaO-B_2O_3-SiO_2体系玻璃。采用FT-IR、DTA对添加了Li_2O的ZnO-BaO-B_2O_3-SiO_2系统玻璃的结构和析晶性能进行了研究,并测试了玻璃的转变温度和热膨胀系数、显微硬度和化学稳定性等性能。结果表明,少量的Li_2O对该系统玻璃结构和析晶性能没有显著影响;当Li_2O质量分数为1.5%,玻璃的均化程度高、玻璃性能好、化学稳定性达到最好。随着Li_2O含量的增加,热膨胀系数呈先减小后增大的趋势,在Li_2O质量分数为1.0%时出现最小值。     

SiO_2-Al_2O_3-CaO-MgO高强度玻璃纤维掺杂TiO_2的结构性能研究

采用高温熔融的方法制备了不同TiO_2掺杂量的Si O_2-Al_2O_3-Ca O-Mg O高强玻璃纤维,借助FT-IR、XRD和SEM等研究了玻璃的结构和性能。结果表明:随着TiO_2掺杂量的增加,玻璃的密度先快速上升后变缓,玻璃的摩尔体积则先快速下降后变缓;玻璃的介电常数出现极大值,介电损耗出现极小值;玻璃纤维的拉伸强度和断裂伸长率均呈现先增大后减小的趋势。XRD和SEM表明掺杂TiO_2不会使玻璃析晶倾向增加,不影响玻璃纤维的拉丝工艺。     

钕-铝系稀土色料的研制

通过钕-铝系列色料合成实验,分析不同配比及不同矿化剂等对色料呈色效果的影响,确定最佳工艺方法。对实验结果进行XRD及色度分析,确定其主晶相为钕酸铝,试样的明度均在70以上,色彩鲜艳亮丽。     

Polycrystalline In2O3 and In2O3/Y2O3 photoanodes

Single crystal In₂O₃ shows promise as a photoanode for the decomposition of water. Because of various difficulties in the preparation of the single crystal material, two simple techniques were developed for the preparation of polycrystalline In₂O₃ anodes. One method involves the thermal decomposition of the nitrate while the other utilizes the chemical vapour deposition technique. Voltammograms and photoresponse spectra of these anodes are compared to the single crystal material. Among other observations, it is noted that the quantum efficiencies of the thermally decomposed films are comparable to the single crystal material. It is also shown that the on-set potential can be shifted to more negative values by forming the mixed oxide In₂O₃/Y₂O₃.     

Na2O-Al2O3-Fe2O3系烧结过程中铝、铁的反应行为

以Al2O3, Fe2O3和Na2CO3为原料,对Na2O-Al2O3-Fe2O3系烧结过程中的反应行为进行了详细研究. 基于溶出率与时间、温度的关系,证明Na2O×Al2O3和Na2O×Fe2O3的生成反应动力学都服从Zhuralev-Lesokin-Tempelman模型,表观活化能分别为186.59和80.92 kJ/mol,表明Na2O×Fe2O3比Na2O×Al2O3在动力学上更易形成;Al2O3易与Na2O×Fe2O3反应形成Na2O×Al2O3和Fe2O3,在1273 K烧结30 min,所得熟料Al2O3溶出率达98.51%;Fe2O3对Na2O×Al2O3的形成有双重作用,在1273 K下可加速Na2O×Al2O3的形成,超过1323 K,促使Na2O×Al2O3分解成Na2O和b-Al2O3,且随着温度升高或时间延长,分解程度增高,从而导致熟料中Al2O3溶出率显著降低.     

Phase equilibrium in binary La2O3-Dy2O3 and ternary CeO2-La2O3-Dy2O3 systems

Cerium oxide doped with oxides of rare earth elements is a multifunctional material, a wide range of uses which is associated with its unique physicochemical properties. Phase diagrams of multicomponent systems are the physicochemical basis for the creation of new materials with improved characteristics.In this work, phase equilibria in ternary CeO₂–La₂O₃–Dy₂O₃ and binary La₂O₃–Dy₂O₃ systems in the whole concentration range were studied. No new phases have been identified in these systems. An isothermal section of the phase diagram of the CeO₂–La₂O₃–Dy₂O₃ system at a temperature of 1500 °С is constructed. No new phases have been detected in the system. It was found that in the studied ternary system solid solutions are formed on the basis of (F) modification of CeO₂ with structure of fluorite type, monoclinic (B), cubic (C) and hexagonal (A) modifications of Ln₂O₃.In the La₂O₃–Dy₂O₃ binary system (1500–1100 °С) three types of solid solutions are formed: based on hexagonal modification A-La₂O₃, monoclinic modification B-Dy₂O₃ and cubic modification C-Dy₂O₃ separated by two-phase fields (A+B) and (B+C), respectively. The boundaries of the regions of homogeneity of solid solutions based on A-La₂O₃ are determined by compositions containing 35–40, 20–25, 15–20 mol% Dy₂O₃ at 1500, 1250, 1100 °C, respectively. From the obtained data it follows that the solubility of Dy₂O₃ in the hexagonal modification of lanthanum oxide is 39 mol% at 1500 °C, 23 mol. % at 1250 °C and 16 mol% at 1100 °C. The limits of existence of solid solutions based on monoclinic B-modification are determined by compositions containing 30–35, 65–60 (1250 °С), 35–40, 55–60 (1100 °С) 40–45, 70–75 (1500 °C) mol% Dy₂O₃.In the studied system, with a decrease in temperature from 1500° to 1100°C, there is a decrease in the solubility of La₂O₃ in the crystal lattice of cubic solid solutions of C-type from 16 to 10 mol%.     

Fe2O3-MnO-Cr2O3-La2O3系统紫色颜料的制备及表征

采用溶胶均匀共沉淀法于低温下合成了含少量稀土氧化物La2O3的紫色颜料，并采用颜色测定、SEM、XRD等手段对颜料的颜色、检度及结晶构造等进行了表征。     

Separation of Phases by Spinodal Decomposition in the Systems Al2O3−Cr2O3 and Al2O3−Cr2O3−Fe2O3

Separation of phases was investigated in the hexagonal (rhombohedral) systems Al₂O₃−Cr₂O₃ and Al₂O₃−Cr₂O₃−Fe₂O₃. The binary system shows a miscibility gap with a T_c of 950°C; the miscibility gap for the ternary system was determined for a constant Cr₂O₃ content of 16.6 mol%. Dark field transmission electron microscopy of solid solutions annealed within the miscibility gap showed dark and light lamellas ∼50 to 200 Å thick. X-ray diffraction results for the solid solutions in the ternary system indicated that, in the early stages of annealing, broadening occurred only on (hkl) reflections where l≠0. There was no major change in the X-ray diffraction patterns of the annealed solid solutions in the binary system. Electron diffraction results indicated, however, that phase separation in both systems proceeded in the [001] direction. Solid solutions in the binary system separated very slowly; the separation could be enhanced hydrothermally. The mechanism of the separation of phases in both systems is spinodal and proceeds as follows: solid solution→intermediate modulated phase→equilibrium phases.     

Properties of RO-Y2O3-Al2O3-SiO2 glasses

The coefficient of linear expansion, glass-transition temperature, temperature at the orset of deformation (strain point), density. Young modulus, microhardness, crystallizability, and contact angle are studied as a function of the composition in RO–Y₂O₃–Al₂O₃–SiO₂ (R=Ca and/or Mg) glass systems. The composition ranges for glasses (with strain point >900°C and coefficient of linear expansion of (32–45)×10^–7°C^–1) that can be used for soldering silicon-nitride ceramics were established.Translated from Steklo i Keramika, No. 12, pp. 5–7, December, 1996     

Bactericidal Effectiveness of O3, O3/H2O2 and O3/TiO2 on Clostridium perfringens

The purpose of this research is to evaluate the bactericidal capacity of different Advanced Oxidation Treatments (AOTs) based on ozone: ozone, ozone/hydrogen peroxide and ozone/titanium dioxide on a wild strain of Clostridium perfringens, a fecal bacterial indicator in drinking water. The dose of ozone consumed ranges from 0.6 mg L^?1 min^?1 to 5.13 mg L^?1 min^?1 depending on the process and on the sample. In the treatments combined with O₃, H₂O₂ dose utilized is 0.04 mM and TiO₂ dose, 1 g L^?1. In order to evaluate the influence of natural organic matter and suspension solids over the disinfection rate, treatments are performed with two types of water – natural water from Ebro River (Zaragoza, Spain) and NaCl solution 0.9%. To achieve 4 log units of inactivation, 3.6 mg O₃ L^?1 is necessary in O₃ treatment, 4.25 mg O₃ L^?1 in O₃/TiO₂ system and 2.7 mg O₃ L^?1 in O₃/H₂O₂ after processing the natural water. In NaCl solution, to get the same inactivation, 0.42 mg O₃ L^?1 is necessary in O₃ treatment, 1.15 mg O₃ L^?1 in O₃/TiO₂ system and 0.06 mg O₃ L^?1 in O₃/H₂O₂ process. Even though the three treatments studied have a high bactericidal activity due to the number of surviving bacteria decreases to non-detectable levels, O₃/H₂O₂ is the most effective system for eliminating C. perfringens cells in a lower contact time, followed by O₃ and finally O₃/TiO₂ system.     

Cr_2O_3-Al_2O_3砖中不同组成Cr_2O_3-Al_2O_3电熔颗粒料的抗侵蚀研究

首先以不同比例的铬绿和氧化铝粉电熔制得Cr2O3质量分数分别为15%、40%、50%、60%、85%、99%的6种Cr2O3-Al2O3电熔颗粒料(其编号依次为CR15、CR40、CR50、CR60、CR85和CR99),然后采用回转渣蚀法研究了此电熔颗粒料(4~1 mm)的抗侵蚀性。结果显示:电熔颗粒料的抗侵蚀性随Cr2O3含量的增加及颗粒尺寸的增大而增强;高Cr2O3含量的CR99、CR85颗粒料在渣面层被侵蚀,主要是渣中的FeO和Al2O3对颗粒料的侵蚀,FeO与骨料中的Cr2O3反应,首先形成(Fe,Cr)3O4尖晶石,再与其他物相反应形成了复合尖晶石,当FeO耗尽后,渗入到颗粒内的Al2O3开始和Cr2O3反应,在颗粒表面形成铝铬固溶体;CR60颗粒料在渣面层和渗透层都存在侵蚀,渗透层的侵蚀主要是CaO、SiO2对颗粒料中铝铬固溶体中Al2O3的熔蚀,形成钙长石、钙黄长石以及玻璃相;Cr2O3含量较低的CR50、CR40、CR15颗粒料在渗透层内的侵蚀机制和CR60颗粒料的相同。