High-temperature Glass Research Articles

Mathematical modeling and flow thermodynamics study of borosilicate glass melt after external addition of Cr2O3

This article uses a high-temperature sintering imaging instrument to test the flowability of borosilicate glass melt doped with Cr2O3, and establishes a mathematical model for high-temperature glass melt spreading. Discuss the glass melt from a thermodynamic perspective by combining model interpretation with experimental characterization. The results indicate that the thermodynamic judgment formula for high-temperature flow spreading of borosilicate glass is: Q≥ρ[A0exp(−T/k0)+S0]−M·δ[A0exp(−T/k0)+S0]1/2. To improve the high-temperature flow ability of borosilicate glass, it is necessary to increase the spreading activation energy Q. On the other hand, it is necessary to reduce the spreading coefficients A0、 k0 and S0. As a refractory metal oxide and active oxide, Cr2O3 plays a role in reducing the spreading coefficient of glass systems.

Degradation characteristics of 3D printed continuous fibre-reinforced PA6/chopped fibre composites in simulated saltwater

AbstractThis paper investigates the performance of continuous fibre-reinforced 3D printed components in salt water medium at room temperature. Markforged® Mark Two 3D printer was employed to fabricate standard specimens made of Onyx and reinforced Onyx specimens with continuous carbon, high-strength high-temperature glass, and Kevlar fibres. Aging process was conducted to characterize the long-term effect of salt water on the mechanical behaviour of fibre-reinforced 3D printed samples. Several mechanical tests including tensile, 3-point bending test and indentation testing have been carried out on the dry and aged standard samples to evaluate tensile strength, flexural strength, micro-hardness, and modulus of elasticity in micro-scale. The mechanical tests revealed the degradation and loss in mechanical properties of the printed samples after aging in salt water. The data highlighted that Onyx samples without continuous fibres experienced the most significant reduction in both tensile (33.54%) and flexural (63.47%) strengths after 1 year, while continuous carbon fibre-reinforced Onyx samples showed comparatively lower strength reductions (28.46% in tensile strength and 18.73% in flexural strength). Optical and scanning electron microscopy were performed to investigate the fracture behaviour of the tested specimens. In addition, the DSC assessment showed a slight change in the thermal properties of aged specimens.

High-temperature Mo-based metallic glass thin films with tunable microstructure and mechanical behaviors

Developing high-temperature metallic glass thin films (MGTFs) with excellent combination properties is crucial for extending the practical applications of metallic glasses. A high-temperature multicomponent Mo-based MGTF with tunable microstructure prepared by single-target magnetron sputtering was presented in this study. Corresponding mechanical behaviors and thermal stability of MGTFs related to microstructure are systemically explored. By adjusting deposition parameters (pressure and power), the microstructure of as-deposited MGTFs can be altered from the dense homogeneous type to the loose nanoglass type. Such structure evolution can be explained by the competition between the surface diffusion and geometric shadowing effect. MGTFs with dense microstructure possess smaller surface roughness, higher hardness, higher Young’s modulus, and better wear resistance. Moreover, they also possess higher thermal stability where the fully amorphous structure and smooth surface can be well maintained after vacuum annealing at 1123 K for 30 min. By contrast, the MGTF with nanoglass microstructure shows inferior mechanical properties and thermal stability due to plentiful loose interface regions, providing abundant free volumes during deformation and acting as favorable crystal nucleation sites during annealing. The correlation between the microstructure and properties of as-deposited MGTFs is clarified with the universal scaling law of glasses. The annealing treatment distinctly increases the hardness and Young’s modulus of MGTFs. Meanwhile, after annealing, pop-in behaviors occur in the as-annealed MGTFs with dense microstructure but not in the as-annealed MGTF with nanoglass microstructure during the nanoindentation. These phenomena can be rationalized by the annihilation of free volumes during annealing and the evolution of the dynamical variable, shear transition zone, for the plastic deformation in MGTFs.

Enabling simultaneous reprocessability and fire protection via incorporation of phosphine oxide monomer in epoxy vitrimer

The conception of epoxy thermosets with both reprocessability and flame retardancy delineates a new horizon in polymer science, offering a material solution that is not only superior in fire safety but is also environment friendly. Herein, a flame-retardant epoxy vitrimer (EV) was prepared using partially bio-based IADPPO (diphenylphosphine oxide itaconic anhydride) and citric acid as curing reagents via a solvent-free process. Their incorporation created covalent adaptable networks (CANs) in the matrix which promote reprocessability and recyclability. The EV exhibits excellent thermal stability with high initial decomposition temperature (T-5wt% ∼308 °C) and high glass transition temperature (Tg ∼107 °C), similar to the blank EV (115 °C). The flame retardancy, mechanical properties, transesterification-based reprocessability, and flame-retardant mechanism were investigated. The EV containing 3 wt% phosphorus (EV IADPPO 3P) achieved UL-94 V0 classification with a limiting oxygen index (LOI) of 27%, while the virgin sample Blank EV (without phosphorus) burned completely. Additionally, increased flexural strength of 79% was observed for EV IADPPO 3P compared to Blank EV. Furthermore, the flame-retardant EV showed high malleability and reparability that could be thermomechanically reprocessed without sacrificing the thermal, mechanical, and flame-retardant properties. Thus, the newly developed epoxy vitrimer is not only fire-safe but fulfills the sustainability goals of today’s society.

Analysing the glaze of a medieval ceramic fragment from the Durres Amphitheater in Albania

The paper analyses the glaze of a ceramic sherd found in the southern sector of the Durres amphitheatre. Specifically, the sherd was found in a layer datable to the late 12th to early 13th century, which can be interpreted as a dismissal layer of a pottery kiln in use between the early and second half of the 12th century. The glaze was analysed using SEM–EDS and Total XRF techniques. The green-ocean glaze with a blue-sky decoration of the fragment has As-Co and Pb–Sn-Si compounds as pigments and phosphorous as a modifying agent and a flux. The glaze composition is SiO2 47.6 wt.%, TiO2 0.22 wt.%, Al2O3 4.08 wt.%, FeOtotal 0.22 wt.%, MnO 0.08 wt.%, MgO 0.23 wt.%, CaO 2.51 wt.%, Na2O 1.55 wt.%, K2O 5.16 wt.%, P2O5 3.01 wt.%, SnO2 4.13 wt.%, As2O5 4.13 wt.%, PbO 25.4 wt%. Fe is expressed as FeOtotal. The trace elements composition (ppm) is Co 3684, Ni 1023, Cu 819, Zn 3070, Bi 3172, and Sr 205. We introduced a robust glaze classification scheme based on chemistry. This scheme categories the glaze as alkaline-lead SnO2-opacified. We examined uncommon compounds formed in various textural contexts to establish the production origin and technique peculiarity. The glaze glasses form three different compositional domains: one represents the parental high-temperature initial glass composition, and two are related to immiscible segregations forming at lower temperatures. Five phases of the apatite supergroup were identified, along with other phases distributed throughout the glaze. The compounds present, such as Pb and Sn silicates, leucite, and k-feldspar and their balances, constrain the firing temperature to 720 ℃ and 900 ℃, respectively.

Raman Spectroscopy Study of Ternary Glass Structure of CaO-SiO2-B2O3

CaO-SiO2-B2O3 terpolymer system is used as the basic raw material to synthesize other glass and melt. Doping Pr, Eu and other rare earth elements can get special performance glass materials with good luminous performance, CaO-SiO2-B2O3 terpolymer system is widely used in packaging substrate and dielectric materials. As an ideal substitute for fluorine, boron in borosilicate has become a new research hotspot of fluorine-free protective slag technology due to its advantages of economic cost and fluxing effect. Raman spectroscopy can be used for real-time observation and microsturcture analysis of materials, which provides a powerful means for the study of high-temperature melt and glass. In this work, CaO-SiO2-B2O3 ternary glass was prepared and Raman spectrum of glass was measured, which provided the necessary basis for the subsequent analysis of its properties, structure and the relationship between its components.

Temperature measurement of molten glass under batch feeding process by means of electrical resistance tomography

Electrical Resistance Tomography stands out as a powerful tool applicable to opaque environments, particularly in scenarios involving highly contaminated flows, gas–liquid two-phase flows with elevated void fractions, and electrically-conductive fields. The semi-conductive nature of high-temperature molten glass renders resistance tomography suitable for determining temperature distributions within such optically opaque mediums. This study aims to extend the application of the tomography technique to the spatial measurement of temperature in high-temperature molten glass. In order to verify the effectiveness of the developed system, a preliminary test was conducted by using an electrolyte solution in water to explore the overall system capabilities. Following the confirmation of the effective resolution of the proposed system, the measurement apparatus was employed for the actual temperature measurement of molten glass. The developed equipment featured sixteen independent electrodes, a low-impedance multiplexer, amplifier, rectifier, and a oscillating signal generator. Electrical potentials of the electrodes were recorded using a high-impedance amplifier as well as a data logging system. Upon collecting the electrical potential dataset, reconstruction computations were executed using the software. The measurement results show that the developed measurement system facilitates the acquisition of quantitative temperature distributions, as evidenced by the injection of a batch of low-temperature glass beads.

Coupled fluid-thermal-structural analysis during the air cooling for glass tempering

The tempering process of plate glass involves rapidly cooling the high-temperature glass using an array of impinging air jets, inducing desired stress during cooling. Consequently, the formation of tempering stress results from the coupled interaction among flow, heat transfer, and stress. However, most previous studies have commonly neglected the influence of the flow field by assuming a uniform and constant distribution of heat transfer coefficients at different positions on the glass plate, which deviates from actual situations. This study employed a fluid-thermal-structural coupled simulation approach to predict the non-uniform residual stress distribution in tempered glass and investigate the interaction mechanisms among flow, heat transfer, and stress. Simultaneously, to validate the reliability of the method and model, this study experimentally investigated the single-nozzle jet impingement cooling for glass tempering. The study concluded that the simulation results were consistent with the experiment. Subsequently, a comparative analysis was performed between the fluid-thermal-structural coupled simulation results based on real boundary conditions and the thermal-structural coupled simulation results based on ideal uniform heat transfer coefficient boundary conditions. The results revealed non-uniform distributions of both heat transfer coefficient and temperature due to varying localized flow characteristics. Consequently, the ratio of surface compressive stress to internal tensile stress along the width direction of the glass was not a fixed value but ranged from 1.63 to 2.38. Furthermore, significant differences were observed in the stress distribution under the simulations of fluid-thermal-structural coupling and thermal-structural coupling. Therefore, it is recommended to employ the fluid-thermal-structural coupling method when predicting localized stress distribution.

Chemically recyclable polyolefin-like multiblock polymers.

Polyolefins are the most important and largest volume plastics produced. Unfortunately, the enormous use of plastics and lack of effective disposal or recycling options have created a plastic waste catastrophe. In this work, we report an approach to create chemically recyclable polyolefin-like materials with diverse mechanical properties through the construction of multiblock polymers from hard and soft oligomeric building blocks synthesized with ruthenium-mediated ring-opening metathesis polymerization of cyclooctenes. The multiblock polymers exhibit broad mechanical properties, spanning elastomers to plastomers to thermoplastics, while integrating a high melting transition temperature (Tm) and low glass transition temperature (Tg), making them suitable for use across diverse applications (Tm as high as 128°C and Tg as low as -60°C). After use, the different plastics can be combined and efficiently deconstructed back to the fundamental hard and soft building blocks for separation and repolymerization to realize a closed-loop recycling process.

Structural evolution and mechanical properties of SiO2-Al2O3-MgO-B2O3 glasses with partial substitution of MgO by MgF2

SiO2-Al2O3-MgO-B2O3-MgF2 glasses were prepared using a high-temperature melting method, and their amorphous nature was confirmed through X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) and magic angle spinning nuclear magnetic resonance (MAS-NMR) were used to investigated structural changes in the glass. It is found that substituting MgO with MgF2 disrupted the Si-O and Al-O networks in the high-temperature glass melt structure, reducing the degree of glass network polymerisation and viscosity. During cooling and annealing, moderate amounts of fluoride ions (F−) promoted the linkage of a partially fragmented glass network by converting [BO3] and [AlO5] into [BO4] and [AlO4]. An increased F− content improved the mechanical properties of the glass, including flexural strength, Young's modulus, and hardness, which peaked at 157.50 MPa, 95.21 GPa, and 838.57 HV with 2 mol% MgF2 substitution. These findings advance our understanding of the behavior of MgF2-substituted glass.

Development of A High-temperature Piezoelectric Ultrasonic Transducer Based on a Glass Substrate

The piezoelectric ultrasonic transducer is a key device in ultrasonic applications. In oil logging, the bottom-hole temperature increases with the drilling depth. With the rapid increase of deep and ultra-deep well exploration, the bottom-hole temperature can reach 175°C or even higher, so new requirements are made for the stability of piezoelectric ultrasonic transducers for logging to work in such high-temperature environments. In this paper, a high-temperature piezoelectric ultrasonic transducer (HT-PUT) based on the high-temperature glass substrate has been developed and characterized in detail. After HT-PUT device fabrication and electromechanical experimental tests, it is shown that both the resonant frequency curve and the effective electromechanical coupling coefficient can be regulated and optimized by changing the size of the through-hole cavity in the glass substrate. After designing an appropriate through-hole cavity, the effective electromechanical coupling coefficient of the HT-PUT in the thickness-extensional mode can be significantly improved by 64.9%. The HT-PUT was tested in the temperature range of 25 °C to 250 °C, and its resonant frequency was only shifted down by 3.2%. This work demonstrates a high-temperature glass-based piezoelectric ultrasonic transducer that can operate in harsh conditions above 250°C, such as oil and gas exploration applications.

Identification of heat transfer coefficient including radiative effects at the glass/mold interface

This paper is devoted to the identification of the heat transfer coefficient between a high temperature glass and a cast iron punch taking radiative effect into account. A 1D numerical thermal model taking the radiative effects into account has been developed to simulate the contact between a punch and a glass cylinder. It was coupled with an inverse identification methodology to determine the heat transfer coefficient using experimental data carried out in the LAMIH. First, the sensitivity of the identification of the heat transfer coefficient with respect to different parameters (initial glass temperature, thermocouple position, radiation) will be introduced. A second part will show the identification of heat transfer coefficient using experimental data taking into account radiative effects.

Dynamic process of single water, water with additives and ethanol droplet impinging on high-temperature quartz glass surface

Dynamic during liquid droplet impacting on the high-temperature solid surface was a fundamental phenomenon during water mist fire extinguishing process. In the present study, water, water with different extinguishing agent including 5 % NaCl solution and 3 % AFFF solution, and ethanol are selected as the droplet liquid. The dynamic of liquid droplets with fall heights from 0.2 m to 1.2 m impacting on the heated quartz glass with temperatures varying from 25 °C to 500 °C is investigated. The impacting phenomena and the spreading diameter are analyzed. The results show that the phenomena can be divided into deposition, gentle bubble boiling, transition and atomization for water, 5 % NaCl solution and 3 % AFFF solution, while deposition, receding breakup, atomization and film boiling for ethanol. The non-dimensional maximum spreading factor for water, 5 % NaCl solution and ethanol shows a power function with the Weber number. For 3 % AFFF solution, however, the non-dimensional maximum spreading factor firstly increases and then decreases with the increase of Weber number. The surface temperature has minor effect on the maximum spreading of water and 5 % NaCl solution droplet compared to that of 3 % AFFF solution and ethanol droplets.

High-temperature malleable Ta-Co metallic glass developed by combinatorial method

Development of metallic thin films with comprehensive properties fulfilling the needs of modern Micro/Nano Electro Mechanical Systems (M/NEMS) devices remains challenging. Here, a fully amorphous Ta90Co10 is screened out by combinatorial sputtering and atomic manufacturing technique, and the Ta90Co10 thin film metallic glass exhibits simultaneously a super-high crystallization temperature of 1325 K, a high hardness of 16.3 GPa, a high strength of 5000 MPa, and a large plastic strain exceeding 50%, outperforming all existing thin film materials. The excellent properties can be attributed to the atomic-scale structural heterogeneity induced by formation of different configurations in amorphous structure. The present work provides an approach to develop new M/NEMS-based thin film materials with outstanding comprehensive properties.

Economic thickness and life cycle cost analysis of insulating layer for the urban district steam heating pipe

The direct buried steam pipeline with effective insulation has great potential application in the district heating systems. In this study, a life cycle cost model for the direct buried steam pipeline was established, and an optimization method was proposed to improve the insulation performance. The influences of insulation material and pipe diameter on the total life cycle cost, economic thickness, energy efficiency, and payback period were analyzed. Under the low-temperature working conditions, the composite insulation scheme composed of high-temperature resistant glass wool (HTRGW) and SiO2 aerogel blanket (SAB) exhibited excellent economic efficiency. Moreover, the life cycle cost and economic thickness show a significant decrease with the increase of pipe diameter, and the economic benefit increased appropriately. When the pipe diameter increased from DN100 to DN700, the life cycle cost was decreased by 351 RMB/m, the economic thickness was decreased by 71 mm, and the economic benefit was increased by 30 RMB/m. Under the high-temperature working conditions, aluminium silicate wool (ASW) was involved in the insulation scheme. When the HTRGW/SAB was adopted instead of HTRGW/ASW, the total life cycle cost was reduced by 133–224 RMB/m, the economic thickness was reduced by 52–55 mm, and the economic efficiency was increased by 17–22 RMB/(m·a).

Assembly and interconnection technology for high-temperature bulk acoustic wave resonators

Abstract. A sensor based on a piezoelectric single crystal enables operation even under harsh environmental conditions. In addition to the sensor element, the packaging technology is crucial for sensor performance. In this paper, a suitable assembly and interconnection technology concept of Ca3TaGa3Si2O14 (CTGS) resonators for high-temperature applications is presented as a platform for future sensor assemblies. The concept described here has already been functionally tested as a temperature sensor (Schulz et al., 2021). The concept includes a sapphire base plate, a housing lid, and a spacer made from aluminium oxide (Al2O3). The substrate is metallised with platinum manufactured into thin film and thick film technology. The ceramic components are fused with glass solder. The connection of the resonator to the conductive tracks is realised by thermosonic bonding with 25 µm platinum wire. Initially, the stability of the metallisation must be investigated before subsequent electrical testing under high temperature. Diffusion processes play a major role in this temperature range, and the stability of the layer is a necessary condition for subsequent investigations. A suitable set of bonding parameters and the strength of the platinum bonds prior to and after thermal load is analysed. Shear tests are used to evaluate the quality of the ceramic materials fused with glass solder after thermal ageing. The dielectrical properties of sapphire and glass solder such as the isolation resistance, the relative permittivity, and the loss factor at high temperatures are evaluated using interdigital structures. The loss factor is measured on both bare interdigital structures and the samples coated with glass solder to make an estimation about the conductive behaviour up to 1000 ∘C. A ceramic lid for the sensor housing is attached by a high-temperature stable glass solder. Since platinum conductors are fed through this glass solder connection, the electrical conductivity of the glass solder is characterised at high temperature. Furthermore, the hermeticity of the assemblies is verified by means of helium leakage tests. These investigations are the basis for the implementation of an assembly and interconnection technology that is suitable for reliable operation under extreme temperature conditions. The packaging technology also offers further possibilities for pressure or chemical sensors that can withstand high-temperature loads.

Parsimonious viscosity–composition relationships for high-temperature multicomponent glass melts

ABSTRACT The activation energy of glass melt viscosity, η, is nearly constant at temperatures at which η < 100 Pa s. Provided that the preexponential factor is a composition-independent constant, only the activation energy is a function of composition, and viscosity–composition relationships of utmost simplicity can be formulated to provide a welcome advantage in computational fluid dynamics modeling of glass melting furnaces processing multicomponent glasses. Using a dataset with over 3000 viscosity values acquired experimentally for a temperature and composition region of low-activity nuclear waste glasses, we have generated three linear models for viscosity as a function of temperature and composition. Model A quantifies the effects of 20 viscosity-influencing components. Model B achieves a similar prediction accuracy after setting aside volatile components, whose concentrations may vary during glass processing. A parsimonious Model C reduces the number of viscosity-influencing components to a mere seven: Al2O3, B2O3, CaO, Li2O, Na2O, SiO2, and Others. In each model, the “Others” component summarizes the fractions of the remaining components. For all three models, the component coefficients are determined with a high confidence (low standard error) and a high coefficient of determination: 0.972 for Model A, 0.970 for Model B, and 0.949 for Model C.

High-Temperature Malleable TaCo Metallic Glass Developed by Combinatorial Method

High-Temperature Malleable TaCo Metallic Glass Developed by Combinatorial Method

Mechanical properties of natural ultra-high-pressure high-temperature impact glasses at the nanoscale by PeakForce QNM

Ultra-high-pressure high-temperature (UHPHT) glass from astroblems is a very promising natural material from the point of view of the fundamental problem of the structure and properties of a substance formed under extreme PT-conditions. Such glasses consist of disordered aluminosilicate and silicate micro-sized phases with a heterogeneous structure with domain from units to tens of nanometers in size. We used AFM to evaluation the mechanical properties distribution at nanoscale in UHPHT glasses from the Kara astrobleme. The results of AFM were supplemented with optical and electron microscopy data. It is shown in the work that the nanomechanical properties of glasses measured using by PeakForce QNM generally correspond to the macroscopic properties of a bulk sample. We measured the Young's modulus for the first time for aluminosilicate and silicate phases of UHPHT glasses. AFM can be an effective tool for studying at the micro- and nanoscale mechanical properties of such rigid materials.

Thermochemistry of the binary system nitrocellulose + dimethyl 4,4´-dinitroheptanedioate

The DSC measurements of the binary mixtures of nitrocellulose (NC) and dimethyl 4,4´-dinitroheptanedioate (DNHD), of expected fine plasticizing properties, were carried out. It was concluded that depending on the time interval between measurements, in cases of specifically low DNHD content in NC mixtures DNHD did not crystallize. The course of the melting process during the second and subsequent measurements performed on the same sample indicates that the process was taking place in confined spaces, i.e. pores as well as in unconfined space. The occurrence of two i.e. high-temperature and low-temperature glass transitions as well as β-relaxation was observed, depending on the composition of the samples and time interval between the measurements. The thermochemical properties of the investigated DNHD/NC binary system are complex and allow to conclude that thermal behavior of the samples across a variety of concentration and temperature ranges, reflects limited miscibility of the components used.