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Preparation of Fe-Co-B-Si-Nb bulk metallic glasses by laser powder bed fusion: Microstructure and properties
摘要： In this work, laser powder bed fusion (LPBF) was employed for the preparation of {(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 bulk metallic glasses (BMGs). Microstructural evolution, thermal stability and mechanical properties of LPBF-processed samples using different laser power and scanning speed were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microscopy analysis (EPMA), electron backscatter diffraction (EBSD), differential scanning calorimetry (DSC) and nanoindentation. The results show that low area energy input facilitates the formation of Fe-Co-B-Si-Nb BMGs with a large amorphous fraction. LPBF-processed sample with an area energy density of 1.25 J/mm2 (at a laser power of 60 W and a scanning speed of 600 mm/s) exhibits a nearly fully glassy microstructure with an amorphous fraction of approximately 99%, meanwhile identical characteristic properties of LPBF-processed samples are correlated with the processing parameters during LPBF. This work demonstrates that LPBF is a promising method to prepare fully amorphous Fe-Co-B-Si-Nb BMGs. The results provide key insights for the fabrication of BMGs and BMGs composites with the desired microstructure possessing almost and properties by additive manufacturing.
关键词： Bulk metallic glasses,Laser powder bed fusion,Amorphous fraction,Crystallization,Microstructure,Nanoindentation
更新于2025-09-23 15:19:57
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Temperature Dependent Spectroscopic Properties of Cu <sup>+</sup> and Dy <sup>3+</sup> Co-Doped Phosphate Glass: Band Gap Analysis and Cu Nanocluster-Enhanced Dy <sup>3+</sup> Luminescence
摘要： This paper reports on the effects of temperature on light absorption and emission in Cu + and Dy3 + co-doped phosphate glass, which is of interest for photonic applications. First, the temperature dependence of the absorption edge of the glass in connection with Cu + ions absorption was assessed. A thermally-induced red shift attributed to Cu + ion-lattice interactions was observed and analyzed through optical band gap determinations in the context of indirect-allowed transitions. Application of the Varshni model for the dependence of the energy gaps with temperature allowed to estimate the 0 K energy gap at 2.87 (? 0.01) eV. Furthermore, Dy3 + photoluminescence (PL) along with Cu nanoparticles (NPs) absorption was monitored in real-time during an isothermal treatment by the in situ concurrent PL and absorption microspectroscopy technique. Periods of enhancement and quenching of Dy3 + emission linked to bidirectional energy transfer processes involving non-plasmonic Cu clusters and plasmonic Cu NPs were revealed. The formation of Cu NPs was promoted by tin(II) used as reductant. It is the first time to the author’s knowledge that the 0 K energy gap is estimated for a highly Cu +-doped glass and that the enhancement of Dy3 + PL by Cu clusters is exposed.
关键词： rare earths,glasses,luminescence,copper,nanoparticles
更新于2025-09-23 15:19:57
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Characteristics of the Structural State of Bismuth Ions in Bismuth-Borate Glasses
摘要： The properties and graphical plots of the properties of bismuth-borate glasses in a wide range of compositions — 20 to 80 mol.% Bi2O3 — are presented. In multi-bismuth glasses both the boron and bismuth ions are found in two coordination states: B3+, B4+ and Bi3+, Bi6+. The [BiO3] groups play the role of a conventional glass former but manifest weakly in the IR spectra.
关键词： structure of bismuth-borate glasses,properties of bismuth-borate glasses,lead-free low-melting glasses,structural role of Bi ions
更新于2025-09-19 17:15:36
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Near-infrared and upconversion luminescence of Tm3+ and Tm3+/Yb3+-doped oxyfluorosilicate glasses
摘要： Oxyfluorosilicate glasses-doped with different concentrations of Tm3+ and Tm3+/Yb3+ ions have been synthesized and characterized their absorption, photoluminescence, luminescence decay and upconversion properties. The Judd-Ofelt intensity parameters have been obtained from the absorption spectrum of Tm3+ single-doped glass and are in turn used to calculate radiative properties such as transition probabilities, branching ratios and lifetimes for the fluorescent levels of Tm3+ ions. Visible and near-infrared emission spectra of Tm3+ and Tm3+/Yb3+-doped glasses have been measured under 473 nm laser excitation. The quenching of emission intensities at higher concentrations of Tm3+ ions has been found to be due to cross-relaxation mechanisms. The Tm3+/Yb3+ co-doped glasses show upconverted emissions under 975 nm laser excitation. The mechanism of upconversion has been explained based on the pump power dependence of upconversion luminescence. The results reveal that the co-doped glasses are promising for optical fiber amplifiers operating at the relatively low-loss wavelength regions.
关键词： Glasses,Optical properties,1.2 μm emission,Upconversion,Judd-Ofelt theory,Tm3+ and Tm3+/Yb3+
更新于2025-09-19 17:15:36
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Luminescence Properties of Dy3+ and Sm3+: Potassium Lithium Borate Glass
摘要： The present paper describes the spectral properties of Sm3+ (0.4 mol%) and Dy3+ (0.4 mol%) ions-doped 20Li2O–10K2O–70B2O3 glasses. X-ray diffraction method was use to confirm the amorphous phase of samples. The physical properties have been determined based on UV absorption spectra. The hypersensitive transition of Dy3+ and Sm3+ is found due to transition of (6F11/2,6H9/2) and (6F7/2), respectively. The emission bands of Dy3+: glass has shown around 572 nm, 612 nm and 646 nm; these emissions are attributed to the transitions of 4F9/2 →6H15/2 (yellow), 4F9/2 - 6H13/2 (red) and 4F9/2 -6H11/2 (red). With regard to Sm3+: glass has three emission bands those have been generated from 4G5/2 → 6H5/2 (616 nm), 4G5/2 → 6H 7/2 (660 nm) and 4G5/2 → 6H9/2 (719 nm) transitions. The current results promise several applications in optical fields such as UV-sensor, developing new color light sources and tunable visible lasers.
关键词： physical properties,rare-earth ions,luminescence,Glasses
更新于2025-09-19 17:15:36
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Thermal properties of high purity zinc-tellurite glasses for fiber-optics
摘要： The thermal properties of the series glasses (TeO2)(0.86-x)(ZnO)x(La2O3)0.04(Na2O)0.1 were studied. The heat capacity and characteristics of transitions between aggregative states were determined by the method of differential scanning calorimetry (DSC) in the temperature range 320-950 K. The experimentally obtained values of thermal conductivity, density and coefficient of thermal expansion at room temperature are as follows: 1.14 ± 0.06 W/(m?K), 5.20 ± 0.02 g/cm3 and (54.6 ± 1.2)?10-6 K-1, respectively. The model-statistical processing of calorimetric data was used to determine the complete set of standard thermodynamic functions together with their approximation to the unexplored low-temperature region by means of parametric similarity. The approach allows predicting the functions for unexplored intermediate glasses compositions.
关键词： heat capacity,thermal conductivity,thermodynamic functions,coefficient of thermal expansion,density,Zinc-tellurite glasses
更新于2025-09-19 17:15:36
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Rich reddish-orange emitting PBTNAPr glasses for laser applications
摘要： Lead borate oxyfluoride glasses containing different amounts of PrF3 with composition PbO–B2O3–TeO2–NaF–AlF3-PrF3 were prepared and characterized for visible and fiber lasers. The amorphous phase and compositional analysis were carried out through powder X-ray diffraction and Fourier transform infrared spectra, respectively. Using the room temperature optical absorption spectra, the spectroscopic properties were determined applying the modified Judd-Ofelt theory. The photoluminescence excitation spectral studies obtained by controlling the emission through Pr3+: 1D2 → 3H4 (604 nm) transition shows prominent excitation band positioned at ~448 nm (3H4 → 3P2). Upon 448 nm excitation, the studied glasses exhibit an intense emission through 1D2 → 3H4 (604 nm) transition along with feeble emissions from 3P1 and 3P0 metastable levels to the inner energy levels. The emission spectra show a shift towards longer wavelengths (called the red-shift) with increase of PrF3 content. The luminescence decay time of 1D2 emission level was found decreased with increase of PrF3 content. The quenching of decay time was assigned to the transfer of energy among the excited Pr3+ ions at relatively higher PrF3 contents. The experimental results show that the studied glasses with 0.1 mol% of PrF3 could be the suitable candidate to design rich reddish-orange emitting lasers.
关键词： Solid state lasers,Photoluminescence,Judd-Ofelt analysis,Lead borate glasses
更新于2025-09-19 17:13:59
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Comparative impact of Nd3+ ion doping concentration on near-infrared laser emission in lead borate glassy materials
摘要： Different concentrations (0.2-1.0 mol%) of Nd3+ doped lead borate glass (LB) systems were prepared by melt quenching technique and have been studied using XRD and optical studies. Based on the calculations of Judd-Ofelt (J-O) theory derived from the optical absorption spectra, three J-O parameters have been obtained. Various radiative parameters (such as radiative transition probability (Arad), branching ratio (βcal), absorption cross-sections (Σ), radiative lifetime (τR) and etc., have been predicted through J-O parameters. Luminescence spectra were measured for all the samples. It has been observed that luminesce intensity gradually increased up to 0.8 mol % of Nd3+ and further increase in concentrations causes that the luminescence spectral intensity falls. This is proposed due to the concentration quenching of neodymium ions in the LB glass system. LB glass system with 0.8 mol % is found to be most intensive one in emission at 1.06 μm related to 4F3/2→4I11/2 in near infrared (NIR) transition.
关键词： Absorption,emission cross-section,Photoluminescence,Judd-Ofelt,Lead borate glasses
更新于2025-09-19 17:13:59
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Laser-stimulated birefringence of Ga2O3-La2S2.95Se0.05 glasses for optical recording of information
摘要： We show an opportunity to change the birefringence of Ga2O3 – La2S2.95Se0.05 glasses doped by Er3+ and La3+ ions at λ = 1150 nm wavelength of cw He-Ne laser under illumination of the femtosecond laser. The variation of the refractive indices was found during illumination by 180 fs laser with frequency about 65 MHz (at wavelength λ = 1045 nm). The laser-stimulated birefringence has been explored versus temperature. The observed laser induced and temperature dependences of the birefringence con?rm a huge contribution of anharmonic phonon subsystems which is typical for chalcogenide glasses. Due to an occurrence of local space charge density asymmetry, the e?ciency of birefringence is enhanced. The anisotropy e?ect exists only during the illumination and is diminished during 10…12 s after switching o? of the photo-inducing laser treatment. There is observed also a correlation between the occurred grating patterns and the values of the birefringence.
关键词： Chalcogenide glasses,Optoelectronic materials,Laser-induced e?ects,Birefringence,Electronic and electrical engineering
更新于2025-09-19 17:13:59
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Energy Transfer and Spectroscopic Investigation of Dy2O3 Doped Li2O–BaO–GdF3–SiO2 for White Light LED
摘要： LGFDy glasses doped with Dy2O3 (0.1, 0.5, 1.0, 1.5 and 2.0 mol %) were synthesised by conventional melt quenching method and various properties are studied by absorption, Judd–Ofelt analysis, photoluminescence, X-ray excited luminescence, decay curve and CIE color chromaticity measurement. Judd-Ofelt parameters (?2, ?4 and ?6) are valuated form JO theory in order to estimate the radiative parameters of the Dy3+ ion excited states. For white light emission, Yellow/Blue (Y/B) ratio and CIE color coordinates for glasses under study are measured from the emission spectra. The energy transfer from Gd3+ to Dy3+ ions has been studied by exciting the glass with 275 nm photon. The higher value of σ (λp) and βR for 4F9/2 → 6H13/2 transition indicates its more potential use in laser application in yellow region. The correlated color temperature for LGFDy glasses is found to be 4264 K. The decay profile of fluorescent level 4F9/2 for different concentration of Dy3+ ions in the present glasses changes to non-exponential from single-exponential for higher concentration (≥0.5 mol %) of Dy3+ ions. Thus the chemical composition of glass and dopant (Dy3+ ions) concentration strongly influence the energy transfer mechanism. The lifetime non-exponential behavior is well fitted to IH-model for S = 6. The quantum efficiency for LBGFDy05 glass is found to be 86%. The systematic investigation signifies the potential of the studied LGFDy glasses for the laser and white light generation application.
关键词： silicate glasses,dysprosium,decay time,energy transfer,resonance energy transfer
更新于2025-09-19 17:13:59