Optical Characteristics of Porous Glasses Matrix and Its Light-conducted Mechanism

The optical properties of matrix of porous glasses and phase-separated glasses were investigated by visible spectroscopy and infrared spectroscopy. The experimental results show that, both the porous glasses and phase-separated glasses have very good light transmission in visible light region that wavelenth is longer than 560nm. The micropores of porous glasses and the boron-rich phase of phase-separated glasses have strong Rayleigh scatter effects on the visible light, the largest scatter occurrs at 360-370nm; the thicker the glasses, the larger the light scattering. Thus, the pore size distribution and the size of heterogeneous micro zone in boron-rich phase of phase-separated glasses can be measured. After coupled into porours glasses, the most intense absorption of hydrated ions of 〔Co(H 2O) 6〕 2+ shifts from 508nm to 515nm. The production of the most intense absorption and the red shift were owed to Jahn-Teller effect of octahedral field formed by six H 2O molecular and perturbation effect resulted by microporous of porous glasses for its physics-chemical circumstance. As a result, the porous glasses are perfect optical function materials in visible region, which can be assembled by chemical method.

Effect of Thermal Treatment and Acid Leaching Process on Pore Characteristics of Nanometer Porous Glass

Porous glass was prepared by thermally treating sodium borosilicate glass for different time, the effect of thermal treatment on pore size distribution was discussed and the pore size of the prepared porous glass was measured by scanning electron microscopy （SEM） and differential thermal analysis （DTA）. The results show that the optimum porous glass with an average diameter of 80 nm can be prepared by thermal treatment at 600℃ for 12 h and then acid treatment for 12 h in 2 mol·L^-1 hydrochloric acid solution.

FABRICATION OF POROUS GLASS FIBRES AND ITS CHARGING CHARACTERISTICS

Glass fibers, cc diameter of 350 mum to 500 mum, were made of glasses with an initial composition of 66. 55iO(2) - 25B(2)O(2) - 8. 5 Na2O. Being heated at 580 C for 24 hours and leached in HCl solution at 90 C: for 12 hours, the glass fibers were made into porous glass fibers, pore size in the range 25nm to 35nm. The influence of the glass composition cold condition on glass phase separation Is discussed. The transparence of the porous glass fibers before and after being charged with sensitive reagents and the anti-resolve characteristics of sensitized reagent charged were also studied. The results have shown that the transparence of porous glass fibers after being charged with sensitive reagents and the anti-resolve characteristics of sensitive reagents charged in the materials were very well. By combining with special sensitive reagents, the porous glass fibers could be made into a series of fiber optic chemical sensors with different characteristics.

The Dynamics of Acid Treatment in the Preparation of Porous Glass

The phase-separation glasses with composition of Na 2O(9.0)B 2O 3(25.0)-SiO 2(66.0)(in mole ratio)were leached with hydrochloric acid,and porous glasses were prepared.The dynamics of the acid treatment was investigated.The effects of treatment time,temperature and acid concentration on the acid treatment process were studied using HCl as treatment solution.The dynamics equation and apparent activation energy obtained in acid treatment process were dw/dt=a/2t and E=57.74 kJ·mol -1,respectively.The constants of the reaction rate at different temperatures were calculated.On the basis of experimental data the mechanism of acid treatment process and the source of swollen stress,which was the main stress during treatment process,were discussed.

COMPUTER SIMULATION OF PHASE SEPARATION IN CaO-MgO-Fe_2O_3-Al_2O_3-SiO_2 GLASS

The fractal and spinodal decomposition models combined Monte Carlo method were used in computer simulation of phase separation from CaO MgO Fe 2O 3 Al 2O 3 SiO 2 glass. The fractal dimension was applied to quantitative analysis. The mechanism of phase separation was investigated. The results showed that the fractal dimensions and simulated micrographs of phase separation were in good agreement with the experimental results. And the mechanism of phase separation was spinodal decomposition.

STUDY ON PHASE-SEPARATION OF PMMA/SAN BLENDS INDUCED BY GLASS BEADS THROUGH DYNAMIC RHEOLOGICAL MEASUREMENTS

Based on the premise that the addition of glass beads （GB） could hardly influence the linear viscoelasticity in low frequency （ω） region for homogeneous polymer systems, the dynamic rheological behaviors of unfilled and filled poly（methyl methyacrylate） （PMMA）/poly（styrene-co-acrylonitrile） （SAN） blends were studied in order to explore the effect of GB on the phase-separation of binary polymer matrix. Results show that GB has an induced effect on the phase-separation, which embodies that the phase-separation temperature （Ts） of PMMA/SAN blend filled with GB is lower than that of the unfilled system. The higher content of GB, the higher is the ＂secondary plateau＂ of ω in the terminal region of storage modulus （G＇） versus ω plot. The ＂secondary plateau＂ appearing in the terminal region is attributed to the phase-separation of PMMA/SAN blends and it becomes more fiat for filled polymer blends under the same conditions. However, it is suggested that this kind of ＂induced effect＂ is related to the GB content; the higher content of GB particles might enhance the interaction between the particles and polymer matrix. Moreover, it is found that the addition of GB also has an influence more or less on the morphology and domain size of polymer matrix. It is believed that the plot of dynamic viscosity （η＇） versus the loss viscosity （η＂） is sensitive to examine the effect induced by GB on the phase-separation of binary polymer matrix.

PHASE SEPARATION AND CRYSTALLIZATION OF CHALCOGENIDE GLASSES

In this paper the experimental results associated until the phase separation and nucleation and crystallization of chalcogenidc glasses are described. Experi-ments demonstrate that the phas separation may be affected by small amount of additives. It has been found that some chalcogenide glasses could be converted into glass-ceramics without phase separation. The different mechanisms of nucleated crystallization of chalcogenide glasses are discussed and propossed.

Anderson Localization Light Guiding in a Two-Phase Glass

Anderson localization has been realized in several different systems over the years. In this paper we describe a rather unique manifestation of the phenomenon occurring in a two-phase glass composition that guides light. The glasses are a borate or alkali borosilicate composition that when heated separates into two distinct phases of different compositions, a high index phase and a low index phase. When the glass is heated with a specific thermal schedule to develop the phase separation it is then drawn into a rod or fiber, the particulate phase forms elongated strands resulting in a random cross-sectional refractive index pattern. This pattern of refractive index is maintained along the length producing a light guiding behavior over a significant distance that we propose is a manifestation of an Anderson localization phenomenon.

Effect of minor-addition of Fe on structural and mechanical properties of CuZrAl bulk metallic glass

The CuZrAl bulk metallic glass with minor-addition of Fe was prepared by rapid quenching method. The structures were examined by X-ray diffraction （XRD）. The effect of Fe on the glass-forming ability was studied by differential scanning calorimetry （DSC）. The minor-addition of Fe obviously extends the supercooled liquid region ΔTx. The plastic strain of the Cu44Zr48Al7Fe bulk metallic glass is about 1.5%. The microstructures were examined by transmission electron microscopy （TEM）. It is found that when 1%-2% Fe （mole fraction） were introduced into the CuZrAl alloy matrix, nanoscale phase separation occurs in the as-prepared Cu44Zr48Al7Fe bulk metallic glass.

Crystal Growth and Nucleation in Glasses in the Lithium Silicate System

The crystal growth and nucleation in glasses in the lithium silicate system have been investigated. Phase separation in ultimately homogenized glasses of the lithium silicate system xLi2O·(100 ﹣ x)SiO2 (where x = 23.4, 26.0, 29.1, and 33.5 mol% Li2O) has been studied. The glasses of these compositions have been homogenized using the previously established special temperature-time conditions, which make it possible to provide a maximum dehydration and removal of bubbles from the glass melt. The parameters of nucleation and growth of phase separated in homogeneities and homogeneous crystal nucleation have been determined. The absolute values of the stationary nucleation rates Ist of lithium disilicate crystals in the 23.4Li2O·76.6SiO2, 26Li2O·74SiO2 and 29.1Li2O·70.9SiO2 glasses with the compositions lying in the metastable phase separation region have been compared with the corresponding rates Ist for the glass of the stoichiometric lithium disilicate composition 33.51Li2O·66.5SiO2. It has been found that the crystal growth rate has a tendency toward a monotonic increase with an increase in the temperature, whereas the dependences of the crystal growth rate on the time of low temperature heat treatment exhibit an oscillatory behavior with a monotonic decrease in the absolute value of oscillations. The character of crystallization in glasses with the compositions lying in the phase separation region of the Li2O-SiO2 system is compared with that in the glass of the stoichiometric lithium disilicate composition. The conclusion has been made that the phase separation weakly affects the nucleation parameters of the lithium disilicate and has a strong effect on the crystal growth.

STUDY ON THE HYDROLIZATION OF THE Na_2O-CaO-P_2O_5-SiO_2 BIOLOGICAL GLASSES

The bio-glass in the Na2O-Ca2O-P2O5-SiO2 system involved in tins paper is highly bio-active. The hydrolization of this glass with calcium phosphate and low silica is studied. The structure-composition-property relation of the glass is discussed by means of IR spectrum, DTA and SEM. This study shows that: (a)the structure of the glass is mainly chain-like or layer-like; (b) the glass is separated into a calcium phosphate-rich phase and a silica-rich phase; (c)the chuin- or layer-like structure and the separation hare advantages with hydrolization.

Phase separation and crystallization of La2O3 doped ZnO-B2O3-SiO2 glass

In order to investigate the effect of the La2O3 on the phase separation and crystallization of ZnO-B2O3-SiO2 glass, after the occurence of the phase separation and crystallization of glasses by heat treatment, the microstructure morphology and distribution of elements in different sample areas were characterized by the scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS);the non-isothermal crystallization kinetics of the glass samples was studied by using a differential scanning calorimeter(DSC) and the precipitated crystals of crystallized glass were determined by the X-ray diffraction(XRD). The results suggest that the phase separation and crystallization of 60ZnO-30 B2O3-10SiO2 glass occur at glass surface, and the incorporation of small amount(<4 mol%) of La2O3 significantly inhibits the glass phase separation and consequently improves the thermal stability of glass.Doping of La2O3 accelerates the glass crystallization at the elevated temperature(660 ℃), making the depth of crystal layer thicker and diffraction intensity in XRD patterns stronger. However, due to the precipitation of several crystals that occur simultaneously when La2O3 doping amount is 4 mol%, crystallization of the 60ZnO-30B2O3-10SiO2 glass is obviously depressed, the crystallization activation energy Ec and the relative crystallinity Xc of the glass reach the maximum and the minimum values, respectively.Although transition from one-dimensional growth of crystals to two-dimensional growth of crystals results from La2O3 addition, the one-dimensional growth of crystals remains dominant in crystallization process. This work can provide some useful information for preparing glass ceramics with nano-crystals precipitated in the glass surface.

Mechanism of phase separation in BFS (blast furnace slag) glass phase

XRD,TEM,ED,and NMR analyzed four types of blast furnace slags (BFS) with different structures in this paper. The composition requirement for phase separation in BFS glass phase was then put forward,that is the composition of slag locates in the coexisting phase region of melilite and any silicate mineral with Q0 units. The special structure of melilite units,a 5-membered ring with high degree of polymerization (DOP),plays a key role in the formation of phase separation. In BFS system,one with chemical composition of larger ratio of (CaO + MgO/(SiO2 + Al2O3) would be more promising to meet the requirement for phase separation.

Complex Processing of Pulverized Fly Ash by Dry Separation Methods

Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a rule near big cities with well developed infrastructure and high cost of land. Moreover, the pollution of environmental by fine solid wastes is inevitable and takes place in area of residing of a basic part of the population. The only solution is a complex processing of fine wastes with a production of value added materials. New conception of complex processing of PFA is proposed on the base of facilities of Electro-mass-classifier (EMC) and other techniques. The characterization of separated fractions was carried out by SEM and optic microscopy, XRD, laser diffraction, M?ssbauer spectroscopy and other methods. A fine fraction of glass microspheres presents the main interest as filler in various materials.

Phase Separation and Crystallization Induced by Electron Irradiation in Nanoscale Fe_(56.5)Mn_(11)Cr_(8.5)Ni_4Si_(10)C_(10) Metallic Glass

A nanoscale Fe56.5Mn11Cr8.5Ni4Si10C10 metallic glass was irradiated by electron beam in a 200 kV trans- mission electron microscope. Structure evolution in the metallic glass was investigated in situ during continuous irradi- ation, where phase separation was observed after irradiation for 5 min and crystallization was observed after 33.5 min. Based on the analysis of irradiation effect, atomic displacement is believed to be the main reason for the structure rearrangement. Accumulation of atomic displacement increases the energy of the sample and promotes atomic diffusion during transformation. On the other hand, the large specific surface area of the sample also contributes to increasing free energy and atomic diffusion.

Direct TEM Observation of Phase Separation and Crystallization in Cu_(45)Zr_(45)Ag_(10)Metallic Glass

The structural evolution of Cu_（45）Zr_（45）Ag_（10） metallic glass was investigated by in situ transmission electron microscopy heating experiments. The relationship between phase separation and crystallization was elucidated. Nucleation and growth-controlled nanoscale phase separation at early stage were seen to impede nanocrystallization, while a coarser phase separation via aggregation of Ag-rich nanospheres was found to promote the precipitation of Cu-rich nanocrystals.Coupling of composition and dynamics heterogeneities was supposed to play a key role during phase separation preceding crystallization.

玻璃分相联用机械化学法脱除废旧含铅玻璃中重金属铅

传统分相法采用热酸浸提工艺脱除CRT锥玻璃分相产物中重金属铅,酸浸过程强酸消耗量大,废酸无法回用,易引发酸污染。目的 为了绿色、高效回收CRT锥玻璃分相产物中重金属铅,方法 采用乙二胺四乙酸(EDTA)作为浸提剂,通过机械化学法研究锥玻璃中重金属在快速分相和机械活化浸出过程中的迁移转化规律,揭示影响重金属脱除率的主要因素和作用机制。结果 结果表明:在分相处理过程中锥玻璃所含Pb,K,Ca等元素主要富集在呈连通结构的富B_(2)O_(3)相中。在随后湿法球磨浸提过程中,分相产物中富B_(2)O_(3)相在机械活化作用下快速溶解到水中,同时富B_(2)O_(3)相中所含金属离子与EDTA形成可溶络合物,且可从分相产物中脱除。锥玻璃所含Pb,K,Ca等金属脱除率随EDTA添加量增大、球磨转速提高、球磨时间延长等不断提升,但随液固比增大呈先升高后降低趋势。当EDTA添加量(质量分数,下同)为80%,球磨转速500 rpm,液固比0.8时,球磨处理30 min,分相产物中Pb,K,Ca,Al脱除率分别达到98.79%,94.92%,95.17%,65.71%,获得SiO_(2)质量分数超过92%的高硅氧玻璃粉末。结论 研究结果可为含重金属玻璃绿色、高附加值利用提供借鉴与参考。

不同K值含Ag碱硼硅酸盐玻璃的析晶行为研究

基于K_(2)O-B_(2)O_(3)-SiO_(2)三元体系玻璃,在固定玻璃组成参数R值的基础上,设计了不同玻璃组成参数K值含Ag碱硼硅酸盐玻璃。采用熔融法制备了基础玻璃,在析晶温度范围内经过一步法热处理,所有样品内部都析出了球形的AgCl晶粒。研究表明,玻璃组成参数K值对含Ag碱硼硅酸盐玻璃体内AgCl晶粒的析出产生了明显影响。对于设计制备的弱分相体系玻璃,玻璃组成参数K值的改变可以影响玻璃网络的聚合度,但玻璃的分相并不是影响玻璃析晶的主要因素。通过玻璃结构分析,玻璃组成参数K值的改变能够对ZrO_(2)在玻璃网络中的存在状态产生影响,进而降低ZrO_(2)在玻璃网络中的溶解度,增加了基础玻璃中的成核位点,从而对含Ag碱硼硅酸盐玻璃的AgCl析晶行为产生重要影响。

硫分离对模拟高放玻璃固化体黄相形成的影响

为抑制高放废液玻璃固化过程中黄相的形成,采用Ba(NO_(3))_(2)将高放废液中的SO_(4)^(2-)以BaSO_(4)沉淀形式分离后,再采用熔融法制备硼硅酸盐玻璃固化体,探究硫分离对玻璃体熔制过程中黄相形成的影响。结果表明,对于模拟废液掺量为20%的样品,硫分离前在800~1 000℃范围内黄相的量随温度升高逐渐增多,硫分离后则未观察到黄相。硫分离前的黄相主要成分为Na_(2)SO_(4)、BaSO_(4)、Na_(2)MoO_(4)、BaCrO_(4)和Na_(2)CrO_(4),硫分离后的玻璃表面存在少量BaCrO_(4);硫分离后废物包容量28%时仍未观察到黄相,显著高于硫分离前的废物包容量(<16%)。

PVME/PS共混体系相分离行为的液态簧振动力学谱的研究

本研究利用自制的液态簧振动力学谱(RMS-L)技术研究了聚甲基乙烯基醚/聚苯乙烯(PVME/PS)二元共混物的玻璃化转变及相分离动力学过程,并选取了不同质量比样品,对每个样品从低温至高温的升降温循环测量。结果表明:(1)RMS-L方法可以灵敏地对不同混合比例的高分子共混体系玻璃化转变和相分离过程进行实时检测;(2)以纯PVME和纯PS玻璃化转变温度为基础,从11组待测样品中挑选组分比为5∶5的样品进行了分析,发现样品的玻璃化转变温度随着组分的变化而变化。而当温度达到某一点时样品会发生相分离。(3)当样品经过第二次升温时发现共混体系的玻璃化转变温度及相分离温度点均有变化,这说明在经过一次升温后样品已经被分为新的相;(4)结合不同比例样品的力学谱结果,发现共混体系相分离行为对时间和温度具有一定的依赖性,并且通过这种规律分析了高分子共混物相分离的动力学行为。