Microstructural Probing of （1-x） GeS2- x Ga2S3 System Glasses By Raman Scattering

Roman scattering measurement of （ 1 - x ） GeS2-x Ga2S3 system glasses was conducted in order to understand the microstructural change caused by the addition of Ga2S3 . According to the change of Raman spectra with the addition of Ga2S3, two main structural transformations were deduced ： the gradual enhancement of ethane- like structural units S3 Ge- GeS3 （ 250 cm ^- 1） and S3 Ga- GaS3 （270 cm ^- 1 ） and the appearance of charge imbalanced units [ Ga2 S2 （ S1/2 ）4 ]^2- and [Ga（ S1/2 ）4 ]^- . And this change of structural aspect seems to give as a clue to understanding the cause of the increased rare-earth solubility.     

Synthesis and electrochemical characteristics of xLi2MnO3·（1-x）Li- （Ni1/3Co1/3Mn1/3）O2 compounds

xLi2MnO3·(1-x)Li(Ni1/3Co1/3Mn1/3)O2 (x=0.25, 0.40, 0.55) compounds were prepared by low-heating solid state reaction. In the voltage range of 2.70-4.35 V, the discharge capacity of the electrode decreased with the increase of x, with a better cyclability. However, when cycled between 2.7 and 4.6 V, the cathodes delivered much larger capacities and their capacities increased with the introduction of Li2MnO3. Moreover, it was found that the discharge capacity gradually increased with the cycle number. The rea...     

Forming regularity and relation between composition and property of B2O3-BaO-ZnO glass

B2O3-BaO-ZnO glass was prepared by using conventional melt quenching technology. The forming regularity and the relationship between the composition and the property of B2O3-BaO-ZnO glass were investigated. The results show that the composition range for forming B2O3-BaO-ZnO glass is very wide, but the content of B2O3 has a limit within mole fraction of 25%-75%. When the content of B2O3 is over the limit, the melt will be divided into two phases with different compositions and structures, whereas too low content of B2O3 will result in the crystallization of the melt during the cooling process. The thermal expansion coefficient, the transition temperature and the resistivity of the glass at room temperature are (5-10)×10-6 ℃-1, 480-620 ℃ and (1.5-3.0)×1010 Ω·m, respectively.     

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

The bio-glass in the Na_2O-Ca_2O-P_2O_5-SiO_2 system involved in this paper is highly bio-active.The hydrolization of this glass with calcium phosphateand low silica is studied.The structure-compositicon-property relation of the glass is discussed by means ofIR spectrum,DTA and SEM.This study shows that:(a)the structure of the glass is mainly chain-like orlayer-like;(b)the glass is separated into a calciumphosphate-rich phase and a silica-rich phase;(c)thechain-or layer-like structure and the separation hareadvantages with hydrolization.     

The Mixed-Alkali Effect on The Resistance of Glass to Water

Based on the composition of float glass, the resistance of glass to water, in which a small amount of K2O (0-1.0 wt% ) was substituted for equivalent amount of Na2O, was investigated by means of glass grains testing. The components extracted from the glass and total alkalinities in extraction solution were determined by atomic absorption spectroscopy and neutralizing method, respectively. The composition of the glass was 14.4 K2O Na2O, 4.0MgO, 8.2CaO, 1.4Al2 O3, 72.0 SiO2, and the minimum extraction ratio of oxides (maximum durability) occurred at a K2 O/Na2O ratio of 0.051( by weight) due to the presence of the mixed-alkali effect. The relative extraction ratio of alkali oxides (R2O) was greater than that of alkaline earth oxides (RO) . By means of mixed-alkali effect and lowing relative contents of R2O in the glass, the resistance of float glass to water was improved and its mildew-proof ability was therefore increased.     

Effect of Network Modifiers on Spectroscopic Properties of Erbium-doped Phosphate Glasses

The integrated absorption cross section ∑abs, peak emission cross section σemi , Judd-Ofeld intensity parametersΩ1 ( t = 2,4,6), and spontaneous emission probability AR of Er3 ions wre determined for Erbium doped alkali and alkaline earth phosphate glasses. It is found the compositional dependenee of σemi is almost similar to that of ∑abs , which is determined by the sum of Ω1 (3Ω2 10Ω4 21Ω6 ). In addition, the compositional dependence of Ω1, was studied in these glass systems. As a result, compared with Ω4 and Ω6 , the Ω2 has a stronger compositional dependence on the ionic radius and content of modifiers. The covalency of Er-O bonds in phosphate glass is weaker than that in silicate glass, germanate glass, aluminate glass, and tellurate glass,since Ω6 of phosphate glass is relatively large. AR is affected by the covalency of the Er3 ion sites and correspands to the Ω6 value.     

INFRARED AND RAMAN SPECTRA STUDIES OF THE GLASS IN THE SYSTEM OF LiCl-Li_2OP_2O_5

Infrared and Roman Spectra of two kinds of glass systems of Li_2 O-P_2 O_5 and LiCl-Li_2O-P_2O_5 were studied and the influence of LiCl on the glass structure was discussed. The results show that in the system of Li_2O-P_2O_5, Licl can not only play a dresser part, but also exist in network gaps in a free state. When x(x=Li_2O/P_2O_5 mole fraction) is smaller and the content of LiCl is lower, LiCl causes the structare of phosphatic glass to break as Li_2O and (PO_2Cl) groaps. With the increase of x and the content of LiCl, the number of LiCl existing in dissociation state increases, too. When x is larger than some value (about 1.4), LiCl exists in a dissociation state entirely.     

Crystal Structure Stability of Simulated Sr_(1-1.5x)Y_xTiO_3(x=0-0.12) Waste Forms

A series of Sr_(1-1.5x)Y_xTiO_3(x = 0-12) solid solutions were synthesized by a solid state reaction process.The effects of reaction temperature and dopant on the crystallinity,microstructure and morphology of Sr_(1-1.5x)Y_xTiO_3(x=0-0.12) were investigated.Pure and single-phase perovskite-type Sr_(1-1.5x)Y_xTiO_3(x0.08) solid solutions were obtained at 1 400 ℃ for 6 h.The perovskite-type SrTiO_3 and pyrochlore-phase Y_2Ti_2O_7 coexisted for x = 0.08-0.12,leading to an unstable and unfavourable solid solution structure for long-term immobilization of the ~(90)Sr.The X-ray diffraction patterns for Rietveld refinement analysis confirmed the formation of a Sr_(1-1.5x)Y_xTiO_3(x = 0-0.12) continuous solid solution.Stretching and bending vibrations were assigned in the infrared region.The SrTiO_3 grain size increased with Y content.The leaching behavior of Y~(3+) from the waste forms of Sr_(1-1.5x)Y_xTiO_3 was controlled by its structural change.     

Low temperature sintering and dielectric properties of Ca-Ba-Al-B-Si-O glass/Al2O3 composites for LTCC applications

The effects of various SiO2 contents on both the microstructures and properties of Ca-Ba- A1-B-Si-O glass/Al2O3 cotrtposites were investigated by FTIR, DSC, XRD and SEM. The experimental results show that increasing SiO2 content in the glass leads to the increase of [SIO4] units, increases the continuity of glass network, and decreases the trend to crystallization of composites. The shrinkage of samples rises rapid around the glass softening temperature and the final shrinkage of samples decreases with increasing SiO2 content in the glass. Borosilicate glass/Al2O3 composites with 60wt% SiO2 sintered at 875 ℃ for 15 min show better properties： a bulk density of 3.10 g,cm-3, a porosity of 0.23 %, a er value of 7.55 and a tan 8 value of 0.00053 （measured at 10 MHz） and a well matching with Ag electrodes.     

RESEARCH ON CHEMICAL AND PHYSICAL ACTIVATION OF γ-C_2S

This paper reports the experiments of chemi-cal and physical activation of γ-C_2S and their results.Chemi-cal activation is that the addition of active substances to γ-C_2Scan promote its 3 days hydrated ratio to 20% and 7 days to26-31%.Physical activation,on the other hand,by irradiat-ing γ-C_2S with energetic ray,can promote its 3 dsays hydrat-ed ratio to 29%.Our experiments illustrate the mechanisms ofγ-C_2S chemical activation and physical activation.The for-mer is the formation of the insoluble by combination of theadded active substances with Ca(OH)_2,which is dissolvedfrom γ-C_2S,breaks the γ-C_2S dissolving-precipitating equilib-rium and promotes its hydration process.As a result,CSHhydrate is formed more rapidly.The latter is that the elasticcollision between the enegetic particles,which eater the γ-C_2S,and cause some atoms in lattice to deviate from their normalpositions and become interstitial atoms,and forms vacancy de-fects simultaneously.As crystal defect density increases,freeenerg     

Crystallization Mechanism of Na2O-CaO-Al2O3-SiO2-F Glass Containing Cr2O3

The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1 .5 % (mass fraction) Cr2O3 can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr2O4] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO3 grew epitaxially.     

The oxidation state of sulfur detected in Na2O-CaO-SiO2 float glass by X-ray absorption near edge structure spectra

The oxidation state of sulfur is detected in Na2O-CaO-SiO2 float glass by synchrotron radiation X-ray absorption near edge structure (XANES) spectra at the sulfur K edge. The measured spectra show the only presence of S6+ in the Na2O-CaO-SiO2 float glass and the oxidation state of sulfur do not change with the increase of glass depth. It is also found that, after the melt has gone through the molten tin bath, the S6+ is the dominant species, but S2- is also present on both surfaces. It is not certain whether cation bonds to S2- or not, because there are many cations dissolved in the melted tin which makes the spectrum complicated.     

Self-cleaning glass coated with Fe^3＋ -TiO2 thin film

The self-cleaning glass coated with Fe^3 -TiO2 photocatalytic thin film was prepared by sol-gel process from the system Ti(OC4H9),-NH(C2H4OH)2-C2H5OH-H2O containing FeCl3. The microstructure and properties of the film were studied using differential thermal analysis-thermogravimetry(DTA-TG), X-ray diffration (XRD) and scanning electron microscope(SEM). The transmittance of the self-cleaning glass was measured by using UV-Vis spectrometer. The effects of content of Fe^3 and the thickness of Fe^3 -TiO2 thin film on the photocatalytic ac-tivity were examined. The results show that the photocatalytic thin films are mainly composed of Fe3O4 and TiO2 particles within 10-100 nm. The appropriate amount of Fe^3 is effective for improving the photocatalytic activities of TiO2. The best photocatalytic activity is obtained when the molar ratio of Fe^3 to TiO2 is 0. 005 and the glass is coated with 9 layers.     

Electrochemical properties and structure of MlNi_(5-x)Sn_x system

The electrochemical properties and structure of M1Ni5-xSnx(x=0-0.5) hydrogen storage alloys were investigated by pressure-composition isotherms, electrochemical measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic parameters. With a small amount of tin substitution, the cycle life increases by 52% (0.5C) and 42% (1.0C), but maximum discharge capacity decreases only by 3.0% and 3.5%, respectively. The cycle life is obviously improved by the low volume expansion and the formed SnO2 surface layers upon electrochemical cycling. The substitution of Ni by Sn leads to an increase of the unit cell volume and charge-discharge cycle life and decrease of the plateau pressure, hysteresis and the hydrogen storage capacity. The standard enthalpy of hydride formation decreases with increasing tin substitution. The main factor that influences the standard enthalpy of the hydriding reaction is the number of the outer orbit electrons and not the atomic size factor.     

Thermal behavior and lithium ion conductivity of L2O-Al2O3-TiO2-SiO2-P2O5 glass-ceramics

A lithium ion conductive solid electrolyte, L2O-Al2O3-TiO2-SiO2-P2O5 glass with NASICON-type structure have been synthesized and transformed into glass-ceramic through thermal-treatment at various temperatures from 700 to 1 000 ℃ for 12 h. The differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance techniques were employed to characterize the samples. The experimental results indicated that the capability of glass forming in this system is superior to that of L2O-Al2O3-TiO2-P2O5. The glass has an amorphous structure and resultant glass-ceramic mainly consisting of LiTi2(PO4)3 phases. Impurity phases AlPO4, TiO2, TiP2O7 and unidentified phase were observed. With the enhanced heat-treatment temperature, grain grew gradually and lithium ion conductivity of glass-ceramics increased accordingly, the related impedance semicircles were depressed gradually and even disappeared, which could be analytically explained by the coordinate action of the ’Constant phase element’ (CPE) model and the ’Concept of Mismatch and Relaxation’ model (CMR). When the sample is devitrified at 1 000 ℃, the maximum room temperature lithium ion conductivity comes up to 4.1×10-4 S/cm, which is suitable for the application as an electrolyte of all-solid-state lithium batteries.     

COLOUR-CHANGING MECHANISM IN P_2O_5-Nb_2O_5-Li_2O NONCRYSTALLINE SYSTEM

Raman, IR spectra, RDF and visible spectrum were used to study the glass structure and the valence states of niobium ions in P_2O_5-Nb_2O_5-Li_2O noncrystalling system. The colour-changing mechanism was studied. For 10Nb_2O_5xP_2O_5(90-x)Li_2O (x=40,45,50,55) system glasses, it was known that the glass colout changing from light gold-yellow to blue with increasing is aroused by the Nb~(3 ) ion increasing, not by the change of niobium ion coordination.     

Transmission properties of a new glass ceramic and doped with Co2+ as saturable absorber for 1.54 µm Er glass short pulse laser

The preparation and characteristics of a new transparent glass ceramic were described. Crystal phase particles with nanometer size were successfully precipitated in glass matrix, which was confirmed to be one of indium aluminum zinc oxide compounds (InxAlyZnzO). The presence of aluminum (Al) and indium (In) impurities in the zinc oxides (ZnO) crystal lattice leads to some changes of the carrier concentration in the material and then promote the sharply changes of transmission spectra in IR range wavelength. And subsequently, the IR cut-off edge blue shifted from 5.5 μm in base glass to 3 μm in transparent glass ceramic sample. Furthermore, passive Q switched 1.54 μm Er glass laser pulses with pulse energy of 10 mJ and pulse width of 800 ns were successfully obtained by using the cobalt doped transparent glass ceramic as a saturable absorber.     

Preparation and bioactivity of sol-gel macroporous bioactive glass

Bioactive glass is well known for its ability of bone regeneration,and sol-gel hioactive glass has many advantages com- pared with melt-derived bioactive glass.3-D scaffold prepared by the sol-gel method is a promising substrate material for bone tissue engineering and large-scale bone repair.Porous sol-gel glass in the CaO-SiO_2-P_2O_5 system with macropores larger than 100μm was prepared by the addition of stearic acid as a pore former.The diameter of the pore created by the pore former varied from 100 to 300μm.The formation of a hydroxyapatite layer on the glass was analyzed by studying the surface of the porous glass by scanning elec- tron microscopy,energy dispersive spectroscopy,X-ray diffraction,and Raman spectra after they had been immersed in simulated body fluid(SBF)for some time,and the porous glass shows good bioactivity.     

Preparation of BN／SiO2 ceramics by PIP method

The precursor infiltration and pyrolysis(PIP) method for preparation of BN/SiO2 composites was used to improve mechanical properties, dielectric properties and feasibility of high temperature dielectric parts with large dimensions and complex shapes. In the processing procedure, the porous BN ceramic matrix was first successfully prepared by compacting the mixed powders of B and BN and then sintering them at a certain temperature under normal pressure of N2. The polycarbosilane(PCS) solution was vacuum infiltrated into porous BN ceramics at the room temperature and then at 800℃ in the air to depolimerize out amorphous SiO2, and sintered further at 1 300℃ in N2 to get BN/SiO2 composites. The microstructure of materials was studied by means of X-ray diffraction and electron probe micro analysis. The thermo-decomposition mechanism of PCS was investigated by a TG-DTA and infrared (IR) spectrum analysis. The flexural strengths were measured by the three-point bending method. The dielectric constant and the loss tangent were measured by the wave-guide method. The results show BN/SiO2 composites were fabricated. The obtained composites posses a flexural strength of 61.96 - 93.31 MPa, the dielectric constant in the range of 3.50 - 3.78 and the order of magnitude of the loss tangent at 10^-3 , which are good for the high tempera turedielectric parts with large size and complex shapes.     

Effect of SiO2/B2O3 Ratio on the Property of Borosilicate Glass Applied in Parabolic Trough Solar Power Plant

This work aimed to analyze the glass material used for sealing the end of a thermal collector in a parabolic trough solar power plant. Based on matched sealing requirements and application performance of glass and Kovar alloy 4J29, one borosilicate glass material(GD480S), whose expansion coefficient was similar to that of Kovar alloy 4J29, was studied. Moreover, the effect of the ratio of Si O2 to B2O3 on the glass properties was explored in detail by Fourier transform infrared spectroscopy. As the Si O2 to B2O3 ratio in the glass increased from 4.18 to 5.77, the expansion coefficient showed a decreasing trend from 4.95×10-6/ ℃ to 4.55×10-6/ ℃. In addition, the water resistance performance improved, enabling the glass material to seal well with the alloy for application in a trough solar power plant. Thus, the increase in the Si O2 to B2O3 ratio made the glass structure more compact and improved the glass performance to meet the requirements of an industrial tubular receiver.