晶核剂Cr2O3、Fe2O3对玻璃熔化性能的影响

高炉渣的主要成分与玻璃相似,采用熔融法以高炉渣为主要原料制备微晶玻璃(高炉渣配比为70%),以少量纯化学试剂调整基础玻璃成分,通过实验研究了晶核剂Cr2O3、Fe2O3对玻璃熔化性能的影响规律.结果表明:基础玻璃中加入0.5%~2.5%的Cr2O3作晶核剂时,随着Cr2O3加入量的增多,熔化温度呈现逐渐升高趋势,当向基础玻璃中加入1.0%~3.0%Fe2O3作晶核剂时,随着Fe2O3加入量的增多,熔化温度逐渐降低.将0.5%~2.5%Cr2O3、1.0%~3.0%Fe2O3按一定比例配合作为复合晶核剂,总量控制在3.5%,Cr2O3与Fe2O3对玻璃熔化性能的影响可以互相抵消.晶核剂Cr2O3、Fe2O3的引入,可明显降低玻璃的熔化性温度,为了保证玻璃液的顺利浇注成型,至少应将温度控制在1360 ℃以上.     

Cr2 O3、TiO2对高炉渣制备微晶玻璃晶化方式的影响

以包钢高炉渣为主要原料,采用熔融法制备CaO-SiO2-MgO-Al2O3系微晶玻璃,主要通过差热分析方法,并借助于Augis-Bennett方程和Ozawa方程研究了分别添加2%Cr2O3和8%TiO2作晶核剂时基础玻璃的晶化方式.研究结果表明:添加2%Cr2O3作晶核剂时,晶体生长指数均可实现大于3,晶化方式为整体晶化;而添加8%TiO2作晶核剂时,晶体生长指数均不可能大于3,晶化方式为表面晶化.因此,Cr2O3是高炉渣制备透辉石类微晶玻璃适宜的晶核剂成分,可单独用作晶核剂,而TiO2无法使基础玻璃整体晶化,不能单独用作晶核剂.研究结果为利用高炉渣成功研制开发透辉石类微晶玻璃在晶核剂种类选择确定方面提供了理论指导.     

包钢高炉渣制备微晶玻璃的析晶方式研究

以包钢高炉渣为主要原料,采用熔融法制备CaO-MgO-Al2O3-SiO2系微晶玻璃,通过差热分析(DTA)、X射线衍射(XRD)、扫描电子显微镜(SEM)分析方法,并借助Ozawa方程研究了添加不同数量晶核剂时的析晶方式.研究结果表明:分别加入8％ CaF2、8％ TiO2和4％ P2 O5作晶核剂时,晶化指数n均小于3,析晶方式为表面析晶;当加入晶核剂为8％ P2O5时,晶化指数n大于3,析晶方式为整体析晶.     

CaO-Al2O3-SiO2系球晶结构微晶玻璃装饰板材的研制

以水淬磷矿渣为主要原料，加入适当的化工原料，采用熔融法制备了F-CaO-Al2O3-SiO2系球晶结构微晶玻璃。借助XRD、偏光显微镜对其晶相组成、微观结构进行了表征，并探讨了晶核剂对晶化的影响及玻璃化学的稳定性能。     

炉渣组分对CaO-Al2O3-SiO2-TiO2-MgO-Na2O渣系粘度的影响

针对高碱度高氧化铝含氧化钠的CaO-Al2O3-SiO2-TiO2-MgO-Na2O六元渣系,采用有限制的混料均匀设计方法设计实验,在1773 K温度熔融还原条件下测定了该渣系的粘度. 利用偏最小二乘法回归分析,建立了炉渣组分与粘度的回归方程,利用回归方程分析了炉渣碱度[w(CaO)/w(SiO2)], MgO, TiO2, Al2O3及Na2O对炉渣粘度的影响. 结果表明,回归方程拟合的关联系数RC2为0.9945,方程可很好地预测该渣系的粘度. 在实验范围内,炉渣粘度随碱度的增加而增加. 碱度一定时,炉渣粘度随MgO, Al2O3, Na2O含量的增加而逐渐降低,随着TiO2的增加先降低后增加. 当炉渣碱度小于3.1、MgO质量含量大于4%、Al2O3大于20%、TiO2在3.1%~6.1%、Na2O大于0.75%时,1773 K温度下炉渣粘度均小于2 Pa×s,此时渣系粘度完全满足实际冶炼要求.     

煤灰渣在Cr2O3-Al2O3-ZrO2砖表面润湿与渗入行为的研究

将灰分(w)为6.81%,挥发分(w)为32.68%的煤制成煤灰后,压成圆柱形的煤灰柱放在Cr2O3(w)含量约为90%的Cr2O3-Al2O3-ZrO2砖上,再推入管式加热炉中,在Ar气氛下,通过升温试验(升温至1200℃)和保温试验(升温至1165℃保温20min),考察了煤灰渣在Cr2O3-Al2O3-ZrO2砖表面的润湿与渗入行为。结果表明无论是升温试验还是保温试验,煤灰柱的变化过程完全一致,都经历了变形、熔融和润湿等一系列的变化。对升温试验过程中煤灰柱变化的观察和照片的处理结果均表明煤灰柱在1100℃时局部凹进去形成不规则形状;在1165℃时煤灰完全熔化,煤灰柱变成半球形;在1180℃时接触角<90°,煤灰渣开始在Cr2O3-Al2O3-ZrO2砖表面发生润湿。对升温试验后的Cr2O3-Al2O3-ZrO2砖表面和渣表面的化学组成分析表明有大量Fe堆积在煤灰渣与Cr2O3-Al2O3-ZrO2砖表面接触处,而邻近处几乎没有发现Fe,可能是由于Fe与Cr2O3-Al2O3-ZrO2砖中的一些组分形成了某种晶相,使得Fe很难进入Cr2O3-Al2O3-ZrO2砖;接近煤灰渣的Cr2O3-Al2O3-ZrO2砖表面组成中出现了Ca,说明熔融灰渣中的Ca渗入Cr2O3-Al2O3-ZrO2砖;同时,煤灰渣中出现了Cr,表明在熔融灰渣渗入Cr2O3-Al2O3-ZrO2砖的同时,砖中的Cr也熔入了熔渣中。     

ZnO,ZnO-Fe2O3晶核剂对微晶玻璃显微结构的影响

分析了在K2O-MgO-CaO-SiO2-P2O5-F系统可切削微晶玻璃中,ZnO,ZnO与Fe2O3复合晶核剂对可切削微晶玻璃显微结构的影响.制备的3种试样组分是:一份基础组分,另两份分别添加了ZnO和ZnO-Fe2O3晶核剂.试样均在1400℃下保温1h熔制.根据差热结果制定了晶化温度制度.采用XRD和SEM分析了晶化样品相组成及显微结构.同时测定了试样的性能.结果表明:ZnO可促进玻璃晶化后形成具有晶粒长径比大,相互交织的框架状显微结构,有利于提高样品的强度和韧性.在ZnO与Fe2O3复合晶核剂共同作用下,晶核形成量增多,晶粒变小,抗拉强度及硬度增加,但切削性能降低.     

Cr2O3及TiO2对CaO-MgO-Al2O3-SiO2微晶玻璃着色及析晶的影响

通过X射线衍射、扫描电子显微镜、综合热分析仪和色差计研究了不同含量的Cr2O3和TiO2对以整体析晶法制备的CaO-MgO-Al2O3-SiO2系微晶玻璃的显色和析晶性能的影响.结果表明:在所研究的组成范围内,Cr2O3和TiO2都不改变微晶玻璃的主晶相,生成颗粒状透辉石晶体.Cr2O3会促进晶体尺寸的增长,但是对晶体含量影响不大.TiO2作为晶核剂效果比较明显,能促进晶体长大.随着Cr2O3含量的增加,微晶玻璃的绿色加深,但亮度降低.随着TiO2含量的增加,微晶玻璃的绿色变浅,但亮度增加.     

Fe2O3对铜尾矿基CaO-MgO-Al2O3-SiO2微晶玻璃析晶行为的影响

以铜尾矿为主要原料,通过熔融法制备CaO-MgO-Al₂O₃-SiO₂(CMAS)微晶玻璃,并外掺Fe₂O₃晶核剂对细粒级铜尾矿基CMAS微晶玻璃析晶行为进行优化。利用DSC、XRD和SEM等手段研究了晶核剂用量对细粒级铜尾矿基CMAS微晶玻璃析晶行为和物理性能的影响,借助Ozawa-Chen法拟合计算了析晶动力学参数。结果表明,外掺Fe₂O₃晶核剂用量大于3.72%(质量分数)时,细粒级铜尾矿制备的微晶玻璃可以实现整体析晶。辉石相的析出是玻璃相中的Fe、Mg元素进入[Si(Al)O₄] 四面体晶格配位的结果,Fe³⁺的增加有利于辉石相的析出并降低了析晶活化能,外掺Fe₂O₃晶核剂能够较好地优化细粒级铜尾矿基微晶玻璃的析晶行为和力学性能。     

锑炉渣玻璃陶瓷的研究

本文研究了锑炉渣玻璃陶瓷的组成、热处理工艺对其微晶化过程、结构与性能的影响，论述了Cr2O3、ZrO2、P2O5及TiO2四种氧化物晶核剂的微晶化作用机理，并测定了所研制的锑炉渣玻璃陶瓷的主要性能。研究表明，TiO2为该玻璃陶瓷的最有效的晶核剂。当添加10％时，按本研究确定的原始玻璃配方及热处理工艺获得了一种熔制温度为1360～1380℃、易实现微晶化且材料性能好的锑炉渣玻璃陶瓷。该材料以硅灰石、榍石及钙斜长石为主晶相，配料中锑炉渣的用量高於50％。     

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.     

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。     

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%.     

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.     

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.     

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。     

Effect of temperature and heating rate on the sintering performance of SiC-Al2O3-Dy2O3 and SiC-Al2O3-Yb2O3 systems

Samples of SiC+10 vol%(Al₂O₃+Dy₂O₃) and SiC+10 vol%(Al₂O₃+Yb₂O₃) mixtures were obtained by cold isostatic pressing and sintered for one hour in a dilatometer at 1800 °C and 1900 °C, applying heating rates of 10, 20 and 30 °C/min. The results of the complete sintering cycle indicated that the heating rates do not significantly influence the shrinkage, but that temperature and total sintering time may be relevant factors. The compacts sintered at 1900 °C shrank on average 9% more than those sintered at 1800 °C, and it was found that the sintering time can be reduced by 40–50% at faster heating rates. The maximum shrinkage rates occurred at temperatures lower than those of the sintering thresholds for the two mixtures, two temperatures and three heating rates. It was also found that after formation of the liquid, the mechanisms of particle rearrangement and solution-precipitation were not as fast as reported in the literature, even at high heating rates, for example 30 °C/min, but they are responsible for much of the shrinkage occurring throughout the sintering cycle.     

含Y2O3的ZnO-Bi2O3-B2O3系统玻璃热学与电学性能研究

用红外光谱仪、拉曼光谱仪和差热分析仪研究了用“熔化-急冷”制得的用于SOFC封装的含Y2O3的ZnO-Bi2O3-B2O3系统玻璃的结构和转变温度(Tg);用X射线衍射仪、热膨胀系数仪和高阻计研究了由“模压成型-热处理”制得的该玻璃制品的微晶化、热膨胀系数(α)和体积电阻率(p)情况.结果表明:Y2O3≤0.5～1.0wt.％时,Y2O3能促进[BO3]向[BO4]转变,使α降低;Y2O3≥0.5～1.0wt.％时,玻璃中Bi-O键增多,又使α降低趋势趋缓;随Y2O3增加,其作用可能由破坏网络结构逐渐向增强网络结构转变,致T8先降后升;添加Y2O3延缓了玻璃的析晶;微晶化能提高α和ρ;添加Y2O3虽致α和ρ下降,但其值仍在SOFC封接玻璃的要求范围内.     

Absorption and Emission Spectral Analysis of Sm3 : Bi2O3-B2O3-Li2O Glasses

In order to enhance UV-transmission ability of B₂O₃ based glass, a suitable quantity of Bi₂O₃ and Li₂O salts have been added and hence the UV cut-off wavelength of Bi₂O-B₂O₃-Li₂O glass (abbreviated as BBL glass) has been found to be 268 nm. In this newly developed glass a luminescent rare earth ion namely Sm³⁺ (1 mol.%) has been incorporated to examine its absorption, excitation, emission and lifetimes of different measured emission bands. Under an UV-source, it has displayed a bright orange emission color. Apart from understanding its various optical properties, different physical properties of the un-doped reference glass have been investigated. The XRD profile of this glass has confirmed its amorphous nature. The measured excitation spectrum has shown a bright excitation band at 483 nm with which, the Sm³⁺ glass has been excited and thus obtained four emission bands at 563 nm, 598 nm, 648 nm and 709 nm respectively. An energy level diagram has been shown to explain the emission process involved in the glass system investigated in the present work.

Communicated by Prof. Jinzo Kobayashi