Ultrabroadband mid-infrared emission from Cr~(2+):ZnSe-doped chalcogenide glasses prepared via hot uniaxial pressing and melt-quenching

We reported an ultrabroadband mid-infrared(MIR) emission in the range of 1800 nm–3100 nm at room temperature(RT) from a Cr~(2+):Zn Se-doped chalcogenide glasses(Ch Gs) and studied the emission-dependent properties on the doping methods. A series of Cr~(2+):Zn Se/As40 S57 Se3(in unit wt.%) glass-ceramics were prepared by hot uniaxial pressing(HUP)and melt-quenching methods, respectively. The glass-ceramics with MIR emission bands greater than 1000 nm were successfully prepared by both methods. The effects of matrix glass composition and grain doping concentration on the optical properties of the samples were studied. The occurrence state, morphology of the grains, and the microscopic elemental distributions were characterized using x-ray diffraction(XRD), scanning electron microscope(SEM), and energy dispersive spectrometer(EDS) analyses.     

P2O5对CaO-MgO-Al2O3-SiO2系微晶玻璃析晶的影响

采用熔融法制备了不同P2O5含量的CaO-MgO-Al2O3-SiO2玻璃样品,研究了P2O5对该系微晶玻璃析晶的影响规律.结果表明:在所研究的CaO-MgO-Al2O3-SiO2玻璃中,P2O5的最大溶解量在10.0;质量分数左右,超过其饱和溶解度后将析出α-磷酸钙相.玻璃中添加4.0;质量分数P2O5时以表面析晶为主,析出晶体为钙长石和少量硅灰石.随着P2O5含量的提高, α-磷酸钙逐渐析出,同时钙长石和硅灰石的析出逐渐降低.进一步提高P2O5含量抑制了玻璃的表面析晶,促进了玻璃的分相和整体析晶.当P2O5的含量达到10;时,玻璃以整体析晶为主,在分相区内外区域析出晶体的形态非常相似,均呈现为细小粒状.     

Preparation and Crystallization of Magnetic Glass-Ceramics from the Residues after Sulfur Release and Iron Recovery from Copper Ore Tailings with Varied CaO Content

To comprehensively reuse copper ore tailings (COT), the fabrication of glass-ceramics by the direct sintering method was investigated, where the residues after sulfur release and iron recovery from copper ore tailings were used as raw materials. The effect of the CaO added on the fabrication of glass-ceramics was emphasized. After analysis of chemical composition and thermodynamics, crystallization kinetics were analyzed by Differential Scanning Calorimetry (DSC) and fitted to the Kissinger equation. The crystal phase and microstructure of sintered glass-ceramics heated between 1080 °C and 1100 °C were estimated by X-Ray diffraction analysis (XRD) and Scanning Electron Microscopy (SEM), respectively. Furthermore, the effects of the addition of CaO on the properties of the sintered glass-ceramics have been discussed. The results showed that the magnetic glass-ceramics were sintered by the residues successfully, the color of which was lighter than that of glass-ceramics sintered by raw materials before iron recovery. According to the XRD analysis, hedenbergite, wollastonite and sekaninaite were formed with traces of maghemite and quartz. In terms of crystallization kinetics and sintering results, a decrease in the activation energies of crystallization and in sintering temperature were observed for an increase in the addition of CaO of up to 10 wt.%. Moreover, the properties of the sintered glass-ceramics, including bulk density, linear shrinkage and flexural strength, were enhanced, while water absorption and true density were reduced with the increase of the amount of CaO added.     

铝硅酸盐微晶玻璃摩擦磨损性能研究

在MRH-5A型环-块摩擦磨损试验机上考察了不同载荷下耐磨微晶玻璃与45#钢对摩时的摩擦磨损性能，用扫描电子显微镜和定点探针观察和分析磨损表面形貌和成分，并探讨了材料的磨损机理。结果表明：磨损率随着载荷的增加出现波动，当载荷低于40N时，磨损率随载荷增加而明显增大；而当载荷超过40N时，磨损率随载荷增加而明显降低；在较低载荷下，耐磨微晶玻璃的磨损失效主要源于轻微点蚀和疲劳剥落；在较高载荷下，其磨损失效主要源于表层晶粒塑性变形及疲劳脆性断裂。     

The effect of viscosity on nanocrystallization of strontium fluoride from a silicate glass

This paper describes the importance of the viscosity development in the glass-ceramics process with respect to the mechanism of nano crystallization in oxyfluoride glasses. In the glass system under investigation nano crystalline SrF₂ is formed from a silicate glass Na₂O/K₂O/SrF₂/Al₂O₃/SiO₂. The occurring crystallization mechanism is clarified by the variation of the SrF₂ concentration and the resulting structures. As expected, the mechanism shows similarities to other recently described oxyfluoride systems. The feature of the present system is that during cooling of the melt a liquid/liquid phase separation occurs which is not the case in similar systems containing BaF₂. A droplet phase enriched in strontium and fluoride is formed which is embedded in a silicate rich matrix phase. During thermal annealing, nano crystalline cubic SrF₂ is precipitated inside the droplet phase. As a result, the viscosity of the residual glassy phase increases during the course of the crystallization. The crystal sizes do not exceed 8 nm, neither if the annealing time nor if the temperature is increased.     

Radiation defects in Ce-activated fluorobromozirconate glass-ceramic X-ray storage phosphors

We report on a photostimulated luminescence (PSL) effect in Ce-doped fluorobromozirconate glasses. Small hexagonal or orthorhombic BaBr₂ crystallites are formed in the glass upon annealing. The PSL shows a (381,415) nm doublet which is due to the 5d–4f luminescence of Ce³⁺ in the orthorhombic BaBr₂ crystallites embedded in the glass matrix. The stimulation band of the PSL peaking at 580 nm is probably due to perturbed F centres in the crystallites. After X-irradiation the magnetic circular dichroism of the optical absorption showed a broad band in the spectral range between 440 and 800 nm, having a derivative-like line shape centred at about 600 nm. The spectrum consists of two overlapping bands: one, derivative-like, belongs probably to F-centres, whereas the second band, superimposed on the low-energy region of the F-centre band, is due to a hole centre.     

Li2O-Al2O3-GeO2-P2O5微晶玻璃的微观结构和离子电导率

采用传统熔体冷却法制备了Li3-xAl2-xGex(PO4)3(x=1.1~1.9)体系玻璃,并通过热处理工艺获得了高电导率的微晶玻璃。通过XRD、TEM和交流阻抗等测试方法,研究了该系微晶玻璃的物相组成、微观形貌和锂离子电导率。结果表明:该系统微晶玻璃析出导电主晶相为LiGe2(PO4)3,杂质相为AlPO4和GeO2。当x=1.5时,由于导电主晶相LiGe2(PO4)3晶粒充分长大、分布均匀,所制备微晶玻璃的室温锂离子电导率最高(5.72×10-4 S.cm-1),可以满足全固态锂离子电池对电解质高室温电导率的要求。     

Influence of CoO addition on phase separation and crystallization of glasses of the ZnO–Al2O3–SiO2–TiO2 system

The evolution of structure, phase composition and spectroscopic properties of CoO-doped (up to 5 mol%) titania-containing zinc aluminosilicate glasses with their heat-treatment has been studied using Raman scattering, small angle X-ray scattering, X-ray diffraction analysis and optical absorption spectra. Addition of cobalt oxide was observed to facilitate amorphous phase separation of the parent glass and gahnite, ZnAl₂O₄, crystallization. Cobalt oxide entered phases formed during low-temperature heat-treatments (720 °C), i.e., amorphous phase, enriched in ZnO, Al₂O₃ and TiO₂ and crystalline phase of gahnite. The absorption of these glass-ceramics was defined mainly by tetrahedral Co²⁺ ions located in gahnite nanocrystals. As the temperature was increased further, traces of anosovite solid solution appeared and then decomposed. Even after high-temperature heat-treatments, a certain portion of Co²⁺ ions remained in amorphous zinc aluminotitanate phase and in octahedral sites of inversed gahnite spinel. In glass-ceramics, the residual high silica amorphous phase contained a small quantity of [TiO₄] centers, which content was smaller in Co:ZAS samples as compared with non-doped glass-ceramics.     

斜波发生器的设计准则

 导出了斜波发生器的设计准则，它可表示为γ<-[(2/3)+(g/2)]，或者为α<-[(2/3)+(g/2)](c_V/c²)（γ为Grüneisen系数，α热膨胀稀疏，c_V定容比热容，c流体力学声速，g材料系数）。对一种微晶玻璃的实验测量结果表明，它可用做斜波发生器，在其厚度为20.39 mm时，可以把冲击波改造成上升时间约800 ns的加速度波。     

Er,Yb:YAG微晶玻璃发光特性的研究

高温熔制Er³⁺，Yb³⁺离子掺杂CaO-Y₂O₃-Al₂O₃-SiO₂系统玻璃，并进行微晶化处理，研究了微晶玻璃中Er³⁺离子的发光及上转换发光特性，分析了微晶玻璃上转换发光机理.结果表明：原始玻璃经热处理得到了Er,Yb:YAG微晶玻璃，微晶玻璃中Er³⁺离子在室温下⁴I_13/2→⁴I_15/2跃迁产生横盖1450—1650nm区间的超宽带荧光，荧光半高宽达180nm，这可能由于YAG微晶相中Er³⁺离子与玻璃相中残留Er³⁺离子的共同发光；Er³⁺与Yb³⁺离子局域基质声子能量的降低使微晶玻璃Er³⁺离子上转换发光强度与原始玻璃相比显著提高，绿光、红光上转换荧光强度比玻璃样品分别增强约7和3倍；微晶化后Er³⁺，Yb³⁺离子局域环境发生变化也导致微晶玻璃中Er³⁺离子绿光、红光上转换发光相对强度发生变化. 关键词： 铒 镱:钇铝石榴石 微晶玻璃 荧光光谱