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1.
Silicon - MnO2, NiO, CoO and CuO doped in soda lime phosphate host glass were prepared. Combined optical and FTIR spectra were measured for the studied glasses before and after gamma irradiation.... 相似文献
2.
In a bid to expand the amount of information available on glass systems and their potential applications for radiation shielding design, glass samples with the compositions (30-x)SrO-xAl 2O 3–68B 2O 3–2V 2O 5(x = 5, 7.5, 10, 12.5&15 mol %) coded as SABV0 - 4 were prepared by the melt-quenching technique and analyzed for their optical, structural, physical, and radiation shielding features. The glassy (amorphous) nature of the SABV glass samples was affirmed by broad peaks of X-ray diffraction spectra. Calculated values of density and molar volume shown opposite behavior and the variation of these values were discussed as structural modifications in the glass matrix. From recorded optical absorption spectra optical band gap energy (Eg)-indirect transition, Urbach energy and optical basicity were estimated. FTIR spectra were recorded for all the samples in the range 400 cm ?1 to 4000 cm ?1. The FTIR absorbance spectra unveiled the SABV network structure mainly incorporating of BO 3 and BO 4 units. Raman spectroscopy is achieved to detect the structural changes and at higher wavenumber, B–O stretching modes in [BO 3] observed with one or two NBO's. The results of ESR spectra of glasses have indicated the highly covalent environment of vanadium ions. Analysis of the photon shielding parameters of the glasses which were obtained primarily from FLUKA Monte Carlo simulations and XCOM computations revealed photon energy and glass chemical composition dependence. The mass attenuation coefficient and effective atomic number ranged from 0.2668 to 0.3385 cm 2g -1 and 12.98–15.93 accordingly as the weight fraction of Sr increased from 16.06 to 26.72% in the glasses. Generally, photon shielding ability of the SABV glasses follows the trend: SABV0 > SABV1 > SABV2 > SABV3 > SABV4. The thermal neutron total cross section follows the same trend with values fluctuating between 71.9553 and 80.6268 cm ?1. However, SABV1 showed superior fast neutron moderating capacity among the glasses. The present SABV glasses showed outstanding photon shielding ability compared to common shields. The prepared glasses are thus suitable candidates for radiation protection applications. 相似文献
3.
The optical absorption spectra of undoped soda lime silicate glass together with two glasses doped with either (1 % nano Fe 2O 3 ) or with both (1 % Nano Fe 2O 3 + 5 % cement dust) have been measured from 200 to 2400 nm before and after gamma irradiation with a dose of 8 Mrad. The undoped glass reveals strong UV absorption with two distinct peaks which are attributed trace ferric iron ions present as impurity. Upon gamma irradiation , this base glass exhibits three peaks at 240,310 and 340 nm and the resolution of an induced broad visible band centered at 530 nm. The two doped glasses show an additional small visible band at about 440 nm and followed by a very broad band centered at 1050 nm. Upon gamma irradiation, the two doped samples reveal the decrease of the intensities of the spectrum. The two additional bands are related to ferric (Fe +3) ions to the band at (440 nm) while and the broad band at 1050 nm is due to ferrous iron (Fe +2) ions. The decrease of the intensities of the UV-visible spectrum upon irradiation can be related to of capturing freed electrons during irradiation . Infrared spectra of the glasses reveal repetitive characteristic absorption bands of silicate groups including bending modes of Si–O–Si or O–Si–O, symmetric stretching , antisymmetric stretching and some other peaks due to carbonate , molecular water , SiOH vibrations . Upon gamma irradiation, the IR spectra reveal a small change in the base spectrum while the IR spectra of the two doped glasses remain unchanged. The change of the IR spectrum of the base glass is related to suggested changes in the bond angles or bond lengths of the mid band structural units. The doped glasses show resistance to gamma irradiation because the nano Fe 2O 3 can capture released electrons and positive holes. 相似文献
4.
Heavy metal oxide glasses (composition 60 PbO, 20 Bi 2O 3 mol%) and containing 20 mol% conventional glass formers SiO 2, B 2O 3, and P 2O 5 were prepared. Combined optical and Fourier transform infrared absorption spectra were measured for the prepared glasses to justify the role of glass formers in the optical spectra together with the network structural groups in such glasses. Also, the density and molar volume values were calculated to obtain some insight on the compactness and arrangement in the network. Optical measurements have been used to determine the optical band gap (E g), Urbach energy (ΔE) and the refractive index (n). Optical spectra of all the samples reveal strong UV absorption which is related to the presence of unavoidable trace iron impurities (Fe 3+ ions) contaminated within the raw materials which were used for the preparation of the studied glasses. Additional near visible bands are observed in all prepared glasses due to characteristic absorption of Pb 2+ and Bi 3+ ions. Furthermore, The variations of the luminescence intensity, values of the optical band gap, band tail, and refractive index can be understood and related in terms of the structural changes that take place in the glass samples. The infrared absorption spectra of the prepared glasses show characteristic absorption bands related to the borate or silicate or phosphate network (BO 3, BO 4, SiO 4, PO 4 groups) together with vibrational modes due to Bi-O and Pb-O groups. 相似文献
5.
Alkaline earth oxynitride glasses of (Ca, Mg)–Si–Al–O–N with different CaO/(CaO + MgO) molar ratios (0, 0.25, 0.5, 0.75, and 1) were successfully prepared using the sol-gel method, and their structural compositions were characterised by Raman and FT-IR techniques. The glass dynamic properties of thermal expansion coefficient, glass transition temperature (T g), and static properties of density, molar volume, Vickers hardness and compressive strength were systematically measured and analysed. The results showed that the static properties exhibited an overall regular change as the CaO/(CaO + MgO) ratio gradually increased, while the dynamic properties had an obvious mixed alkaline earth effect, which represented the appearance of an extreme value point in CaO/(CaO + MgO) mole ratios of 0.25 and 0.75, respectively. The typical thermal expansion coefficient and T g of mixed alkaline earth oxynitride glasses deviated far from the linear connection between single alkaline earth oxynitride glasses. Raman spectra and infrared spectra revealed that the ratio value of the Q 3/(Q 2+Q 4) decreased (Q n: n = no. of bridging anions joining SiO 4 tetrahedra) in the mixed alkaline earth oxynitride glasses with increasing the amount of Ca, confirming that Ca decreased the crosslinking between individual tetrahedra via the transformation of Q 3 species into Q 2 and Q 4 species. 相似文献
6.
Bismuth phosphate glasses of the basic composition (Bi2O3 30 mol%-P2O5 70 mol%) with additional dopants 3d TM oxides (0.2 wt%) were prepared by the melting and annealing technique. Combined optical (UV/vis.) and FT infrared absorption spectra were measured for the prepared samples before and after gamma irradiation with a dose of 8 Mrad (8×104 Gy). Optical spectra reveal strong UV absorption bands due to trace iron impurity together with an additional absorption band due to Bi3+ beside characteristic absorption related to specific 3d TM ions with preference for the lower valences due to the reducing effect of phosphate host glass. FTIR spectra show vibrational bands due to phosphate chains with the sharing of absorption bands due to Bi-O vibrations. Gamma irradiation causes limited changes due to the presence of heavy metal Bi3+ ions which show some shielding behavior towards gamma irradiation as revealed by optical and FT infrared absorption measurements. Some suggested photochemical reactions are forward to interpret the changes in the UV spectra beside the formation of an induced phosphorus oxygen hole center (POHC) in the visible region. 相似文献
7.
Novel glass-ceramics of the nominal molar compositions 20Fe 2O 3·20B 2O 3·(60-x)V 2O 5· (xNa 2O or xSrO) (where x?=?0 or 10) were prepared by traditional melt technique. Differential thermal analysis (DTA) was implemented to study the thermal behavior of the prepared glasses. Vanadium pentoxide (V 2O 5), iron vanadate (FeVO 4), sodium vanadate (Na 3VO 4) and strontium vanadate (with different formulae) were crystallized and identified by X-ray diffraction (XRD) analysis under certain conditions of heat-treatment. Further characterization of glass and glass ceramics samples were performed using scanning electron microscope (SEM), density, electrical and dielectric measurements. In conclusion, our study elucidated that the substitution of vanadium by Na + and Sr 2+ ions enhanced the conductivity at 180?°C from 5.11?×?10 ?4 for unmodified glass to 2.93?×?10 ?3 and 1.03?×?10 ?2?S?cm ?1 for Na- and Sr-modified glasses. 相似文献
8.
Some glasses based on Hench’s patented bioglass have been prepared with ZnO replacing Na 2O or CaO in order to investigate their bioactivity in the glassy state or after conversion to their glass-ceramic derivatives.
In-vitro investigations of bioactivity of the prepared glass and their glass-ceramics derivatives were carried out by Infrared
absorption spectra (IR) of the samples before and after immersion in simulated body fluid (SBF) for different time periods
at 37 °C. An X-ray Diffraction (XRD) analysis technique was performed on the glass-ceramic samples to identify the crystalline
phases formed during the controlled thermal treatment. Chemical corrosion experiments were also performed to evaluate the
chemical behaviour of both glassy and the glass-ceramic derivatives towards SBF. The IR results showed that the amount of
the apatite layer formed on the surface of the sample containing ZnO depends on the wt% of ZnO content. The X-ray results
indicate that there are two phases formed: sodium calcium silicate and kilchoanite. Weight loss data were observed to change
depending on the percent of ZnO and the role of housing of Zn 2+ in the glass structure. Corrosion behaviour of glass-ceramic derivatives indicates higher durability than in the corresponding
parent glasses as expected. 相似文献
9.
The effect of introduction of aluminum oxide into the composition of sodium silicate glasses has been studied by IR absorption
and reflection spectroscopy. The change in the spectroscopic characteristics of glasses after their treatment with HNO 3 and AgNO 3 aqueous solutions is analyzed. The concentration profiles of Na + and Ag + ions in the surface layers of these glasses are determined by the HF-sectioning technique. It is found that silver ions predominantly
interact with the [AlO 4/2] - groups in the glass. The leaching of sodium ions, formation of amorphous silica in the surface layers of the treated glass
samples, and exchange of sodium ions by hydrogen ions are revealed from changes in the spectra. 相似文献
10.
The effect of introduction of aluminum oxide into the composition of sodium silicate glasses has been studied by IR absorption
and reflection spectroscopy. The change in the spectroscopic characteristics of glasses after their treatment with HNO 3 and AgNO 3 aqueous solutions is analyzed. The concentration profiles of Na + and Ag + ions in the surface layers of these glasses are determined by the HF-sectioning technique. It is found that silver ions predominantly
interact with the [AlO 4/2] - groups in the glass. The leaching of sodium ions, formation of amorphous silica in the surface layers of the treated glass
samples, and exchange of sodium ions by hydrogen ions are revealed from changes in the spectra. 相似文献
11.
Ternary amorphous samples of 50TeO 2-(50 ? x)V 2O 5- xK 2O compositions with 0 ≤ x ≤ 20 (in mol %) have been prepared using the press-melt quenching method. The optical absorption spectra of glass have been recorded in the wavelength range 300–900 nm by UV-visible spectrophotometer. According to The Tauc and Urbach theories, the optical band gap and width of the tail of localized states have been evaluated. In addition the temperature glass transition ( T g ) of glasses have been determined by differential scanning calorimetry, confirming the amorphous nature of samples. The density and molar volume have been studied, indicating act of K 2O as network modifier. 相似文献
12.
Ternary borate glasses containing LiF, ZnF 2, NaF or CaF 2 were prepared by full replacement of silica by borate in patented Hench′s bioglass. Prepared samples were examined for their corrosion behavior with the expected final formation of fluoroapatite after immersion in SBF (simulated body fluid). Characterization of the glasses was carried by FTIR (Fourier transform infrared) absorption spectra before and after immersion. DAT (deconvolution analysis technique) was used to identify the formation of fluoroxyapatite from FTIR data after immersion in SBF. X-ray diffraction analyses were done for all samples to identify the crystalline phases that were formed after immersion in SBF and also to determine the degree of crystallinity for each sample. Also, scanning electron microscopic (SEM) investigations were carried out to examine the morphological changes of the surfaces upon immersion and the effects of different individual fluoride additives. The solubility testing for glassy samples was performed and the changes in the pH of the leaching solution were measured and evaluated. 相似文献
13.
The quaternary glasses of mixed divalent oxides including ZnO, MgO, CdO within a phosphate network former were prepared. Vanadium pentoxide was introduced as a dopant in the range from 0.5 to 3%. Optical and infrared absorption studies for all glass samples were carried out. The optical spectra reveal the presence of both V 3+ and V 4+ ions in the studied host mixed divalent oxides phosphate glass. Fourier transform infrared absorption spectral analysis indicates the appearance of distinct vibrational bands due to the presence of characteristic phosphate groups depending on the glass composition and the ratio of V 2O 5 content. The optical band gap and Urbach energy were calculated and discussed in relation to the effect of V 2O 5 content. Finally, the glasses were optically and structurally examined affter gamma irradiation with a dose of 80 KGy. 相似文献
14.
Four soda lime silicate glass samples of composition (70 % SiO 2+ 20 % Na 2O+ 10 % CaO mol %) were prepared after adding 5 wt% cement dust to each sample mixture besides 0.1 wt% of one transition metal (TM) oxide of Fe, Co or Cu. The four samples were melted by a conventional melt-annealing technique at 1400 °C for 2.5 h. Density, UV/VIS, FTIR and DC conductivity measurements were performed for each glass. Experimental results indicate that there are only slight differences in the density values. The optical spectra reveal that the TM free sample and the sample containing iron ions have the same spectral features while the samples containing copper or cobalt exhibit distinct characteristic absorption bands due to each TM ion. FTIR spectra reveal characteristic vibrational bands due to stretching and bending modes of the silicate network. DC conductivity data show variations in the values of the studied samples according to the type of TM ions added. All the experimental results were correlated with each other in accordance with the current views on the constitution of the studied glasses. 相似文献
15.
Lead silicate (LS) glasses of the basic composition PbO 75%, SiO 2 25% together with samples containing (∼0.1%) of transition 3d metal oxides (Ti→Cu) were prepared. UV/VIS optical analysis
for as prepared and after successive gamma irradiated samples were used to shed more light on the structural modifications
that occur due to different dopants and different irradiation doses. The UV-Vis. spectral analysis for undoped glass shows
induced absorption bands at 205–400 nm which are assumed to be correlated with the base host glass and dopant transition metal
ion doped glasses and dose of irradiation. The positions of the bands are observed to change slightly by gamma irradiation
due to the combined effect of induced defects from the host base glass or the transition metal added. Gamma irradiation is
observed to cause a decrease in the intensities of the IR absorption bands of the prepared samples accompanied by losing sharpness.
These features are related to more amorphicity or disorder by irradiation or to the possible changes in bond angle or bond
length in the building groups arrangement. 相似文献
16.
The structural, physical, and optical properties of prepared glass samples of the composition formula 30SiO 2-(40-x)B 2O 3-20Na 2O-10Al 2O 3-xY 2O 3, where x = 0, 1, 5, 7 (wt%) were studied before and after gamma irradiation using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-visible spectroscopy. The optical absorption spectra of study glasses were recorded in the UV/visible range of 200–900 nm. The optical band gap energies were calculated from absorption data. These results show that E opt decreases with increasing concentration of Y 2O 3. The changes occurring in the optical parameters obtained from absorption spectra before and after irradiation have been referred to irradiation induced structural defects and compositional changes. 相似文献
17.
A series of Ce 3+/Dy 3+‐doped oxyfluoride borosilicate glasses prepared by melt‐quenching method are investigated for light‐emitting diodes applications. These glasses are studied via X‐ray diffraction (XRD), optical absorption, photoluminescence (PL), color coordinate, and Fourier transform infrared (FT‐IR) spectra. We find that the absorption and emission bands of Ce 3+ ions move to the longer wavelengths with increasing Ce 3+ concentrations and decreasing B 2O 3 and Al 2O 3 contents in the glass compositions. We also discover the emission behavior of Ce 3+ ions is dependent on the excitation wavelengths. The glass structure variations with changing glass compositions are examined using the FT‐IR spectra. The influence of glass network structure on the luminescence of Ce 3+/Dy 3+ codoped glasses is studied. Furthermore, the near‐ideal white light emission (color coordinate x = 0.32, y = 0.32) from the Ce 3+/Dy 3+ codoped glasses excited at 350 nm UV light is realized. 相似文献
18.
Soda lime silicate glasses containing different amounts of iron slag 0–30 % were prepared. The chemical durability of the prepared glasses was examined by immersion in HCl or HNO 3 solutions at room temperature. The results show that the glass durability increases with increasing the amount of slag in the glass composition to a certain amount, then followed by a decrease in the glass durability. Various mechanisms of corrosion and the role of the mobility of cations and their leaching into solution, also the effect of time of leaching are discussed. The densities of all glass compositions were measured. The quantitative analysis obtained from infrared absorption spectra in the range of (400–4000) cm ?1 in relation to the effect of corrosion on the absorption spectra has been studied in terms of structural concepts. The topography of the glass surfaces was observed by scanning electron microscopy (SEM). The concentration percentage of the ions present on the glass surface was determined by Energy Dispersive X-ray analysis (EDX). 相似文献
19.
In the TeO 2-WO 3-GdF 3 glass system, 42 different proportions of glass have been prepared, showing the ideal forming area. The influence of proportions on the density was measured and several devitrified samples were analyzed by XRD. Discussed the internal structure changes and the variation of component concentration by Raman and Fourier transform infrared spectra. The properties and structural features of glasses were analyzed in terms of molar volume. TeO 2 and WO 3 act as glasses former while GdF 3 act as a modifier which forms mixed linkages Te–O–W, Te–F–W, etc. UV–Vis spectra were recorded to determine optical absorption/transmission and energy gap values. These results suggest that the TeO 2-WO 3-GdF 3 glass system could be potentially used as photonic devices and basic materials. 相似文献
20.
Photochromic glasses having composition (SiO 2) 45(B 2 O 3) 35(Al 2O 3) 7.5(Na 2O) 12.5(AgBr), (Cu 2O) doped with (CoO) x , in which, x = 0, 0.006, 0.02 and 0.07 g were prepared using the conventional melt technique. The amorphous nature of these glass samples was confirmed using X-ray diffraction analysis at room temperature. The absorption measurements in the infrared region of the spectrum were recorded in the wave number range (4000–400) cm ?1. Spectral reflectance and transmittance at normal incidence of the prepared glass samples were recorded with a spectrophotometer in the spectral range 200–2500 nm. Experimental and theoretical densities of the prepared glass samples were measured, calculated and compared. Analytical expressions were used to calculate the real and imaginary parts of the refractive indices. Dispersion parameters such as: single oscillator energy, dispersion energy, average oscillator wavelength, and Abbe’s number were deduced and compared. Absorption dispersion parameters such as: optical energy gap for direct and indirect transitions, Urbach energy and steepness parameter were calculated. Effects of doping with cobalt oxide CoO as a transition metal on linear and predicted nonlinear optical parameters were investigated and interpreted. Experimental results indicate that there is an optimum concentration of cobalt doping around 0.006 g. The optical band gap decreases with increasing doping and causes an increase in nonlinear optical parameters. Doping with cobalt oxide improves the linear and nonlinear optical properties of the prepared glasses. 相似文献
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