GeS2-Ga2S3-PbCl2硫系玻璃光学及析晶特征的研究

采用熔融-淬冷法制备了GeS2-Ga2S3-PbCl2系列样品玻璃,测试了样品从可见到中远红外的透过光谱和不同升温速率下的DTA曲线,用Kissinger法计算了析晶活化能E和晶体生长指数n.结果表明:该系列玻璃具有较宽光谱,引入PbCl2使玻璃的短波截止波长蓝移,长波截止基本不变.玻璃具有较好的热稳定性,以体积晶化一维生长方式.其中,90 (0.85GeS2-0.15Ga2S3) -10 PbCl2玻璃具有最大的析晶活化能E=134.44 kJ·mol-1,可作为研究硫系玻璃基质与微晶玻璃非线性效应的理想材料.     

Enhanced Up‐Conversion Luminescence in Er3+‐Doped 25GeS2·35Ga2S3·40CsCl Chalcogenide Glass–Ceramics

Enhanced luminescence in rare‐earth‐doped chalcogenide glass–ceramics is of great interest for the potential integrated optoelectronic devices. However, fundamental mechanism on the enhancement of luminescence upon crystallization remains largely unknown. We report the fabrication and characterization of wide transmission chalcogenide glass and glass–ceramics based on the 25GeS₂·35Ga₂S₃·40CsCl:0.3Er glass composition, and discuss the mechanism of enhanced luminescence. By monitoring the ⁴I_9/2–⁴I_15/2 of Er³⁺ transition, up‐conversion luminescence of 12 times higher was observed in glass–ceramics compared with that in base glass. Electron paramagnetic resonance (EPR) and Raman scattering spectroscopies were employed to obtain the information of selective environment of Er³⁺ ions and microstructural evolution with the crystallization progress. Both of them evidenced that the enhanced up‐conversion luminescence was mainly related to the local environmental evolution from a mixed chlorine‐sulfur coordination to a low phonon energy chlorine coordination in the residual glassy matrix of glass–ceramics.     

Correlation Between Crystallization Behavior and Network Structure in GeS2–Ga2S3–CsI Chalcogenide Glasses

Diagram of the phase transformation behavior of GeS₂–Ga₂S₃–CsI glasses is realized in this article and the structure‐property dependence of the chalcogenide glasses is elucidated using differential scanning calorimetry and Raman spectroscopy. We observe the compositional threshold of crystallization behavior locates at x = 6–7 mol% in (100?x)(0.8GeS₂–0.2Ga₂S₃)–xCsI glasses, which is confirmed by the thermodynamic studies. Structural motifs are derived from the Raman result that [Ge(Ga)S₄], [S₂GeI₂], [S₃GaI], and [S₃Ga–GaS₃] were identified to exist in this glass network. Combined with the information of structural threshold, local arrangement of these structural motifs is proposed to explain all the experimental observations, which provides a new way to understand the correlation between crystallization behavior and network structure in chalcogenide glasses.     

The Effect of PbS on Crystallization Behavior of GeS2‐Ga2S3‐Based Chalcogenide Glasses

Glass‐ceramics of PbS‐doped 80GeS₂·20Ga₂S₃ were fabricated by heat treatments of base glasses at T_g+30°C for different durations. They exhibited improved mechanical properties such as hardness and resistance to crack propagation, and meanwhile retained their excellent infrared transmission. X‐ray diffraction and Raman results indicated that Ga₂S₃ and GeS₂ crystals were precipitated inside glassy matrix. The crystallization kinetics of base glass was investigated using differential scanning calorimetry under nonisothermal conditions. Compared with the previous work concerning on 80GeS₂·20Ga₂S₃ glass, there exists some different features of crystallization behavior. Such variation is discussed and correlated with the network structure and crystallization kinetics in this glass system.     

GeS2-Sb2S3玻璃的三阶非线性研究

采用熔融-急冷法制备了(100-x)GeS2-xSb2S3(x=10%、15%和20%)系列硫系玻璃,测试了样品的折射率、从可见到近红外的透过特性.采用Z-扫描方法测试了样品的三阶非线性特性,分析了Sb2S3的含量对玻璃的线性折射率,透过率和三阶非线性性能的影响.结果表明样品的线性折射率、非线性折射率n2、非线性吸收系数β以及三阶非线性光学极化率χ(3)随着Sb2S3的含量增加而增大,Sb2S3物质的量含量为20%的样品在800 nm处的三阶非线性折射率n2和非线性吸收系数β分别为:n2=3.27×10-10 esu和β= 31.5 cm/Gw.     

Phase Separation in Nonstoichiometry Ge–Sb–S Chalcogenide Glasses

A series of (1 ? x)GeS_2.5 – xSb chalcogenide glasses were prepared using the conventional melt‐quenching method. Their microstructure and thermal response were systematically studied. We observe a compositional threshold of x = 0.25 which corresponds to chemical stoichiometric composition in the calorimetric experiments. It is in good accordance with the Raman scattering results and laser‐induced phase transformation behavior. They also indicate that phase separation of Sb‐rich phase exists in the S‐poor samples. Moreover, we got a structural modeling of this phase separation: (1) at x = 0.25, which is chemical stoichiometric composition, the structural motifs are only SbS₃ pyramid and GeS₄ tetrahedra, and the three‐coordinated SbS₃ pyramid is isolated by GeS₄ tetrahedra; (2) at x < 0.25, the S–S bonds exist in the glass network due to the excess of S; and (3) at x > 0.25, the excess of Sb break the Ge–S and Sb–S bonds to form Sb(Ge)–Sb Bonds, and the Sb atoms segregate from the backbone to nucleate a separate Sb‐rich phase. This work provides a new way to investigate the phase separation of glass networks and helps us to better understand their related physical properties.     

Na2O-B2O3-SiO2-TiO2玻璃分相与析晶的研究

熔融分相法是制备负载型纳米TiO2光催化材料的新方法。该方法是以Na2O-B2O3-SiO2-TiO2系为研究对象,通过制备不同组成的样品,并进行X射线分析及显微分析,进一步研究了熔融分相法中玻璃分相与TiO2析晶的关系。结果表明:组成在玻璃分相区域的样品,有玻璃分相现象产生,TiO2晶体能够析出,而在未分相区域的组成,样品中没有产生玻璃分相,TiO2晶体不能析出;玻璃分相的结构影响了TiO2晶体的生长,相同热处理条件下,组成中硅含量越少,其玻璃分相程度越大,TiO2析晶越容易,TiO2的析晶尺寸越大。     

An unprecedented 2D isopolymolybdate with (3·4)(3·5·8)(3·4·5·6·8)(3·4·5·6) topology

A novel two-dimensional molybdenum oxide polymer, [Mo₄O₁₃]_n · 2nH₃O, has been prepared under specific hydrothermal conditions and characterized by IR spectroscopy and TG analysis. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a (3, 4, 5, 6)-connected 2D layer structure with (3²·4)(3²·5³·8)(3·4²·5⁴·6·8²)(3⁴·4³·5⁴·6⁴) topology, which is constructed by two parallel molybdenum oxide dimeric chains (Mo₂O₁₀)_n bound together by the dimer of Mo₂O₉ subunits via the sharing of corners. Additionally, the electrochemistry activity of compound 1 is also reported.     

GeS2-Ga2S3-PbCl2玻璃的三阶非线性光学特性

采用熔融-淬冷法制备了(100-x)(0.8GeS2-0.2Ga2S3)-xPbCl2(x=0,5,10,15,摩尔分数)系列硫卤玻璃,测试了样品的密度、可见-中远红外的透过性以及样品的折射率,并且根据Z扫描测试原理测试了飞秒脉冲下,样品在800 nm波长下的三阶非线性光学特性.结果表明:非线性折射率n2和非线性吸收系数β均随着PbCl2含量的增加而增大,特别是x=15的样品的非线性折射率n2=2.812×10-17m2/W,非线性吸收系数β=4.298×10-11m/W,较传统无重金属参杂硫系玻璃的三阶非线性性能明显提高.     

The hydration of 11CaO · 7Al2O3 · CaF2 AT 20°C

Hydration at 20°C of C₁₁A₇ · CaF₂ which exists in regulated set cement was investigated by means of conduction calorimetry, differential thermal analysis, scanning electromicroscopic observation, X-ray diffraction and chemical analysis. The process of hydration and rate of hydration were determined and influence of the various calcium sulfates, calcium hydroxide and carboxylic acid upon the hydration of C₁₁A₇ · CaF₂ was discussed. Mechanism of the strength development was also deduced in relation to the structure of hardened paste.     

ZnO对Na2O-CaO-SiO2-P2O5玻璃分相析晶的影响

本文通过熔融法制备了Na2O-CaO-SiO2-P2O5系乳浊玻璃,采用SEM、EDS、X射线衍射、同步热分析仪等对样品进行表征.研究结果表明:该玻璃的乳浊是由分相和析晶共同作用造成的,ZnO对玻璃结构有着显著的影响.随着ZnO质量分数的增加,富磷相的数量先增加后减少;少量氧化锌的加入促进了Na3Ca6(PO4)5的结晶,过多则有Zn2P2O7晶体的生成;随着氧化锌量的增加,白度先升高后降低,在氧化锌质量分数为3％时,白度值最高为86.84％.     

K2O—CaO—Al2O3—SiO2系统玻璃的分相

本文研究了Ｋ２Ｏ－Ａｌ２Ｏ３－ＳｉＯ２玻璃的分相行为，从中发现该系统在液相线下的亚稳不混溶区能一直扩展到含ＳｉＯ２量为５３－６０ｍｏｌ％的截面，Ｋ２Ｏ的引入能使该系统的不混溶温度升高，其分相的结构形貌的液滴状，滴状相是富硅相，含有ＳｉＯ２，Ａｌ２Ｏ３和Ｋ２Ｏ，其尺寸大小服从对数正态分布。     

CaO－Al_2O_3－SiO_2玻璃表面上晶体生长动力学和分相影响

ＣａＯ－Ａｌ＿２Ｏ＿３－ＳｉＯ＿２玻璃表面上晶体生长动力学和分相影响杨晓晶，李家治（中国科学院上海硅酸盐研究所２０００５０）许淑惠（西北轻工业学院７１２０８１）ＳｕｒｆａｃｅＣｒｙｓｔａｌＧｒｏｗｔｈＫｉｎｅｔｉｃｓｉｎＣａＯ－Ａｌ＿２Ｏ＿３－ＳｉＯ...     

含氟CaO-Al_2O_3-SiO_2玻璃分相的研究

在含硫化物的CaO-Al_2O_3-SiO_2(CAS)微晶玻璃系统中,氟作为有效的辅助晶核剂已得到了证明。虽然人们对含氟CAS微晶玻璃的晶化过程进行了较为详细的研究,但其分相以及分相与析晶的关系仍存在着许多值得探讨的问题。搞清楚氟对CAS玻璃分相的影响,无疑对进一步认识分相机理或开发CAS微晶玻璃新产品,都有着不可低估的意义。本     

Glass Formation and Crystallization Behavior of a Novel GeS2–Sb2S3–PbS Chalcogenide Glass System

In the present work, a large glass-forming region was found in the novel GeS₂–Sb₂S₃–PbS system, in which up to 58 at.% PbS could be incorporated without deteriorating the thermal and physical properties of glasses. Infrared (IR) transmitting glass ceramics with a large amount of small-sized crystals (<100 nm) were then produced by choosing sub-stable compositions and annealing at fairly low temperatures (15°–30°C above T _g) for long durations (up to 100 h). Crystals were identified by X-ray diffraction as Pb₂GeS₄, PbGeS₃, PbS, PbSb₂S₄, etc., depending on base glass compositions. Compared with base glasses, glass ceramics showed much improved thermal shock resistance and fracture toughness, making them good candidate materials for IR optics.     

Controllable Formation of the Crystalline Phases in Ge–Ga–S Chalcogenide Glass‐Ceramics

We prepared chemically stoichiometric, S‐poor and S‐rich Ge–Ga–S glasses and annealed them at a temperature that was 20°C higher than its respective glass transition temperature. We aimed at tuning the formation of the different crystals in chalcogenide glass‐ceramics. Through systematic characterization of the structure using X‐ray diffraction and Raman scattering spectra, we found that, GeS₂ and GeS crystals only can be created in S‐rich and S‐poor glass‐ceramics, respectively, while all GeS, Ga₂S₃, and GeS₂ crystals exist in chemically stoichiometric glass‐ceramics. Moreover, we demonstrated the homogeneous distribution of the crystals can be formed in the S‐rich glass‐ceramics from the surface to the interior via composition designing. The present approach blazes a new path to control the growth of the different crystals in chalcogenide glass‐ceramics.     

Glass Formation and Ionic Conduction Behavior in GeSe2–Ga2Se3–NaI Chalcogenide System

Series of glassy and glass‐ceramic samples in the GeSe₂–Ga₂Se₃–NaI system is prepared by melt‐quenching technique and the glass‐forming region is well‐defined by XRD investigations. Na‐ion conduction behavior is systemically studied by impedance measurements. For the glasses in the series (100?2x)GeSe₂–xGa₂Se₃–xNaI, ionic conductivities increased with increasing x, whereas the attributed activation energy of ion conduction decreases. The enhanced mechanism is discussed by employing Raman spectra. In addition, the effect of the crystal phases NaI and Ga₂Se₃ on the ionic conduction behavior in the (70?x)GeSe₂–xGa₂Se₃–30NaI samples is discussed. Although it shows that the poorly conducting crystallites of NaI and Ga₂Se₃ have a negative effect on the ionic conductivities in this series, the highest ionic conductivity of 1.65 × 10^?6 S/cm is obtained in the 45GeSe₂–25Ga₂Se₃–30NaI glass. Finally, this study also demonstrates a possible way to search appropriate Na‐ion solid electrolytes for all‐solid‐state batteries.     

Structural phase transition and high temperature phase structure of Friedels salt, 3CaO · Al2O3 · CaCl2 · 10H2O

Friedels salt, the chlorinated compound 3CaO · Al₂O₃ · CaCl₂ · 10H₂O (AFm phase), presents a structural phase transition at about 30°C from a monoclinic to a rhombohedral phase. It has been studied by X-ray powder diffraction and optical microscopy in transmitted light with crossed polarisers on single crystals prepared by hydrothermal synthesis. The high temperature phase was determined at 37°C from X-ray single crystal diffraction data. The compound crystallises in the space group R c with lattice parameters of a = 5.7358(6)Å and c = 46.849(9)Å (Z = 3 and D_x = 2.111 g/cm³). The refinement of 498 independent reflections with I > 2σ(I) led to a residual factor of 7.1%. The Friedels salt can be described as a layered structure with positively charged main layers of composition [Ca₂Al(OH)₆]⁺ and negatively charged layers of composition [Cl⁻,2H₂O]. The chloride anions are surrounded by 10 hydrogen atoms, of which six belong to hydroxyl groups and four to water molecules. The structural phase transition may be related to the size of the chloride anions, which are not adapted to the octahedral cavity formed by bonded water molecules.