Annealed Glass Samples Research Articles

Johnson–Holmquist-II model of annealed glass and its verification in dynamic compression test

The main purpose of this work is to build a JH-Ⅱ constitutive model of annealed glass under different strain rates and verify its accuracy. Therefore, in this paper, experiments which were carried out on annealed glass samples with the size of 15 mm × 15 mm and numerical simulations are used to investigate the parameters of this brittle material. The tensile strength of the material obtained by split test is 53.688 MPa, because the failure of annealed glass material is controlled by its tensile strength. The compressive strength of 373.074 MPa and elastic modulus E = 77.89 GPa were obtained by quasi-static compression test. Dynamic compression tests of annealed glass at different loading rates were carried out to study the influence of strain rate effect. At the same time, scanning electron microscopy (SEM) technology is used to scan the experimental results and reveal the failure mechanism of annealed glass from the microscopic level. Finally, the model parameters were derived by combining with the literature data.The material model is applied to the numerical simulation of dynamic compression tests of annealed glass. In the dynamic loading of annealed glass, the results of the numerical simulation using the material parameters are basically consistent with the experimental results, including the dynamic damage process and stress–strain relation. In the experiment and numerical simulation, the error of the ultimate strength of the material under different loading strain rates is within 20%. Based on the clear evidence above, it can be concluded that the dynamic failure simulation process of annealed glass using the JH-Ⅱ model in this paper is effective and accurate. It is worth noting that although this experiment was only conducted on small-scale samples suitable for this study, the parameters still have great applicability. And it can provide reference for parameter derivation method.

Structural analysis of mixed transition metal ion doped barium-boro-bismuthate glass system

Transition Metal Ion (TMI) doped barium-boro-bismuthate glasses with composition(10-x)V2O5-xMoO3-25BaO-20B2O3-45Bi2O3 (with x = 0, 1, 3, 5, and 8 mol%) were synthesized using melt quench technique. As synthesized and annealed (at 450°C for 5 hours) compositions were studied by analysing their physical and structural behaviour. The broad XRD profiles of as synthesized glasses confirmed the formation of glassy phase whereas the ordered profiles of annealed compositions depicted the formation of nano-crystalline Bi45BO69 phase (with crystallite size <50 nm) inside the glass matrix. Density of as prepared glass samples increase with increase in concentration of MoO3 at cost of V2O5. The presence of [BiO6], [BiO3], [BO3], and [BO4] structural units inside the glass matrix is depicted by FTIR and confirmed by Raman spectroscopy. The increase in calculated values of N4 indicating decrease in concentration of Non-Bridging Oxygen (NBO), on addition of MoO3. Increase in density and decrease in concentration of NBO, indicated contraction of size which agrees with compositional variation N4. The microstructure and elemental analysis for annealed glass samples typical (MVBBB(x = 0, 2 and 5)) were investigated using FESEM/ EDX technique. The recorded FESEM micrographs of annealed samples, shows crystalline growth at annealed temperature and agrees with XRD analysis.

Reevaluating the efficacy of moderate annealing in nuclear waste vitrification for sustainable high-level waste management

The reliable immobilization of nuclear waste, particularly high-level waste (HLW), is a key issue for sustainable utilization of nuclear energy. Annealing process is adopted in nuclear waste vitrification to improve mechanical properties of products; however, its efficacy on chemical stability of treated HLW glass remain uncertain. This study aims to reevaluate the effects of moderate annealing on chemical durability of sodium borosilicate glass matrix incorporated with simulated HLW. Two types of leaching tests, i.e. acid leaching and the modified Product Consistency Test (PCT), were performed to examine the leaching behavior of HLW glassy products controlled by corrosion mechanisms of ion exchange and hydrolysis, respectively. The acid leaching results showed that annealed glass samples released lanthanum (La) species at a faster rate than that of quenched samples, but the effects of annealing on the release behavior of alkaline and alkaline-earth elements were limited. In contrast, the PCT results showed minor difference between quenched and annealed samples, which suggests that the small structure modification caused by moderate annealing was not comparable with the dominant hydrolysis reaction occurred in the PCT process. According to the free-volume theory, as well as evidences derived from Raman characterization and thermodynamic measurements, La was inferred to exist in the free-volume region in the HLW glass, and the annihilation of free volume during annealing could mobilize La from its stable surrounding environment, and thus reducing the chemical stability of nuclear waste glass.

An optical investigation of silver nanoclusters composite soda-lime glass formed by electric field assisted diffusion

Silver nanoclusters (NCs) embedded in soda-lime glass was synthesized by the electric fieldassisted diffusion (EFAD) and successive annealing. The samples were characterized by UV-Vis absorption spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy (XPS), and lifetime measurements. The experimental results show that the growth of silver clusters is favored by the annealing temperature and dwell time. The as-diffused and annealed glass samples show photoluminescence around 550 nm under UV excitation, which can be associated with the presence of L-center and Ag3 + cluster. And the increasing of the annealing temperature and dwell time results in an appearance of the SPR peak and the decreasing of the luminescence intensities because the Ag3 + clusters grow up into the Ag nanoparticles.

Fracture Origins and Maximum Principal Stresses in Rectangular Glass Lites

AbstractData were studied from tests of new and weathered rectangular annealed glass samples, each consisting of numerous specimens, loaded to fracture. The maximum principal tensile stress at the fracture origin was compared with the single largest maximum principal tensile stress (SLMPTS) within each specimen. The findings indicated that maximum principal tensile stresses at the fracture origins were always less, often significantly so, than SLMPTS in the specimens. In addition, fracture origins rarely, if ever, coincided with the location of SLMPTS in a rectangular glass lite specimen. These results support the notion that glass thickness selection should not be based on a maximum principal stress method.

SERS-applicable silver nanoisland film grown under protective coating

We have used recently developed out-diffusion technique of growing silver nanoisland films on glass surface to grow silver nanoislands under TiO2 layer deposited on the glass. After covering the surface of silver ion-exchanged glasses with TiO2 film using atomic layer deposition technique and subsequent thermal processing of the samples in hydrogen their optical absorption spectra demonstrate the absorption peak corresponding to surface plasmon resonance in grown silver nanoislands. The spectral position of the peak is shifted relatively to the peak observed in the spectra of the nanoisland film grown on the surface of ion exchanged and annealed glass samples without dielectric cover. The applicability of the silver nanoislands grown under several nm thick protective TiO2 coating in surface-enhanced Raman scattering spectroscopy is demonstrated.

An Overview of the Scratch Resistance of Automotive Coatings: Exterior Clearcoats and Polycarbonate Hardcoats

The scratch resistance of coatings used on two highly visible automotive applications (automotive bodies and window glazings) were examined and reviewed. Types of damage (scratch vs. mar), the impact on customers, and the causes of scratch events were investigated. Different exterior clearcoat technologies, including UV curable and self-healing formulations were reviewed, including results from nano- and macro-scratch tests. Polycarbonate hardcoat glazings were tested vs. annealed glass samples using a Taber abraser, with the resulting damage analyzed using transmitted haze measurements and optical profilometry. A correlation between the damage seen in glass samples (many smooth, shallow mars) and the best hardcoat samples (fewer, deeper scratches) and the haze measurements was discussed. Nano-scratch results showed similar fracture forces, but measurably improved mar resistance for the hardcoats/glass system compared to exterior clearcoats.

Thermal properties and crystallization of PbO–MoO3–P2O5 glasses

Thermal properties and crystallization of glasses from PbO–MoO3–P2O5 ternary system were studied in three compositional series (100 − x)[0.5PbO–0.5P2O5]–xMoO3 (A), 50PbO–yMoO3–(50 − y)P2O5 (B), and (50 − z)PbO–zMoO3–50P2O5 (C). Glass transition temperature, crystallization temperature, coefficient of thermal expansion, and dilatation softening temperature of the studied glasses were determined by differential thermal analysis and dilatometry. Crystallization products of annealed glass samples were investigated by X-ray diffraction and Raman spectroscopy. X-ray diffraction analysis of crystallized glasses revealed the formation of PbP2O6, Pb3P4O13, and PbMoO4 in the samples of the B series. In the series A and C in the samples with a high MoO3 content, crystalline compounds of Pb(MoO2)2(PO4)2 and (MoO2)(PO3)2, respectively, were identified. Raman spectra of crystalline samples confirmed the results of X-ray diffraction measurements and provided also information on thermal stability of glasses and formation of glass-crystalline phases in the studied glass series.

Investigations of the non-isothermal crystallization of CaF 2 nanoparticles in Sm-doped oxy-fluoride glasses

Oxyfluoride glass samples in the system SiO 2–Al 2O 3–CaF 2–SmF 3 were produced by using the melt-quenched technique and the kinetics of non-isothermal crystallization of CaF 2 nano-crystals has been investigated. Differential thermal analysis (DTA) has shown an exothermic peak at about 700 °C which was assigned to the CaF 2 nano-crystals precipitation within the glass matrix as was identified by X-ray diffraction (XRD) analysis of the annealed glass samples. It was shown the Ozawa model is most suitable for describing the behaviour of non-isothermal crystallization of CaF 2 nano-crystals within the glass matrix. The mean value of the Avrami exponent was found 1.16 which indicates the diffusion-controlled growth process of nano-particles in the glass system with zero nucleation rate as the single operative mechanism; the activation energy of the crystallization is E d = 379 ± 25 kJ/mol (3.93 ± 0.26 eV). The activation energy of the nano-crystals growth was computed within the same model and agrees very well with the activation energy of the crystallization.

Effects of rehydration on Tb 3+ spectroscopy in sol–gel glasses

Spectroscopy of sol–gel silicate glasses containing Tb 3+ is used to investigate the diffusion of water from the atmosphere into annealed glass samples. In materials that are annealed to 900 °C the blue–violet 5D 3 → 7F J fluorescence is comparable in intensity to green emission from the 5D 4 level. However, the 5D 3 emission is reduced to ∼5% of its original strength in several hours if glasses are exposed to ambient conditions. Re-annealing restores the original intensity of the 5D 3 fluorescence. The degree of fluorescence quenching is shown to depend strongly on initial preparation of the sol–gel materials and on annealing conditions.

Kinetic model for the relationship between mean diameter shortening and age reduction in glass samples

Fission tracks in glass samples are shortened when they experience thermal treatment. Consequently, the observable dimensions associated with track length also diminish. The dimension normally used to characterize track size is the mean diameter of the etched track at the surface, D. Another consequence of length shortening is the reduction of surface density, ρ , implying a reduction of the fission-track age. In this work, a kinetic model is developed to describe the relationship between fission-track mean diameter shortening and surface fission-track density reduction in glass samples, based on geometrical and etching hypotheses. The result is a two-parameter equation given by (1) ρ ρ 0 = D D 0 2 ( 1 + 1 / n ) 4 h 2 + D 0 2 4 h 2 + D 0 2 ( D / D 0 ) 2 2 4 h 2 - D 0 2 4 h 2 - D 0 2 ( D / D 0 ) 2 1 / n in which h is the thickness of the layer removed during etching and n is a parameter related to the latent track geometry and etching reaction rate. The equation was compared with experimental data on Australite glass found in the literature and with fresh data on Macusanite glass presented in this work. The model fits the experimental curves quite well, showing that it describes the etching effects correctly (within its limitations). In addition, the model equation derived in this work can be very useful in age correction of partially annealed glass samples.

Photoluminescent properties of nanocrystallized zinc borosilicate glasses

Zinc borosilicate glass is studied as a scintillating material. Glass samples with zinc oxide concentrations as high as 60mol% were prepared successfully without deteriorating the glass-forming ability. Different post-preparation thermal treatments were carried out on the samples in the temperature range of 300–700°C and for 3–8h duration. A dominant emission band was observed near 400nm in the luminescence spectra with the excitation peak near 260nm. Photoluminescence decay kinetics shows dominant decay times of about 7–10 and 170–200ns with a weak tail down to several tens of microseconds. Thermal treatment was found to enhance the 400nm emission intensity several times with respect to an as-prepared sample and X-ray diffraction analysis confirmed the presence of ZnO crystallized phase in heavily annealed glass samples.